wip: feat: add support for z3 bit rotate exts

z3 > 4.8.8 will return sign_extend and zero_extend operators in the
model, which were not handled by the smt-lib2 decoder, despite being
handled in the encoder. support for these operators has been added

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/docker.yml

@@ -0,0 +1,50 @@
+name: Docker
+
+on:
+  push:
+    tags:
+      - '*'
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Clone Repository
+        uses: actions/checkout@v4
+
+      - name: Configure Docker Metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=ref,event=tag
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+
+      - name: Authenticate to Package Registry
+        uses: docker/login-action@v3
+        if: ${{ github.event_name != 'pull_request' }}
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and Publish Rosette Image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max

.github/workflows/tests.yml

@@ -0,0 +1,102 @@
+name: Tests
+
+on: [push, pull_request]
+
+env:
+  CVC4_URL: "http://cvc4.cs.stanford.edu/downloads/builds/x86_64-linux-opt/cvc4-1.8-x86_64-linux-opt"
+  BOOLECTOR_URL: "https://github.com/Boolector/boolector/archive/3.2.1.tar.gz"
+  CVC5_URL: "https://github.com/cvc5/cvc5/releases/download/cvc5-1.0.7/cvc5-Linux"
+  BITWUZLA_URL: "https://github.com/bitwuzla/bitwuzla/archive/93a3d930f622b4cef0063215e63b7c3bd10bd663.tar.gz"
+  STP_URL: "https://github.com/stp/stp/archive/d70085462f07c8a5a2f1225f727cda3ef505b141.tar.gz"
+  YICES2_URL: "https://github.com/SRI-CSL/yices2/archive/e27cf308cffb0ecc6cc7165c10e81ca65bc303b3.tar.gz"
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        racket-version: ['8.1', 'current']
+        racket-variant: ['CS']
+        allow-failure: [false]
+    name: Racket ${{ matrix.racket-version }} (${{ matrix.racket-variant }})
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.allow-failure }}
+    steps:
+      - uses: actions/checkout@master
+      - name: Setup Racket
+        uses: Bogdanp/setup-racket@v1.14
+        with:
+          architecture: x64
+          version: ${{ matrix.racket-version }}
+          variant: ${{ matrix.racket-variant }}
+      - name: Install solvers
+        # Note that setting LD_LIBRARY_PATH can be removed once this bug is
+        # fixed: https://github.com/stp/stp/issues/485
+        run: |
+          mkdir bin &&
+          wget $CVC4_URL -nv -O bin/cvc4 &&
+          chmod +x bin/cvc4 &&
+          wget $BOOLECTOR_URL -nv -O boolector.tar.gz &&
+          mkdir boolector &&
+          tar xzf boolector.tar.gz -C boolector --strip-components=1 &&
+          pushd boolector &&
+          ./contrib/setup-cadical.sh &&
+          ./contrib/setup-btor2tools.sh &&
+          ./configure.sh &&
+          cd build &&
+          make &&
+          popd &&
+          cp boolector/build/bin/boolector bin/ &&
+          rm -rf boolector* &&
+          wget $CVC5_URL -nv -O bin/cvc5 &&
+          chmod +x bin/cvc5 &&
+          sudo apt-get update &&
+          sudo apt-get install -y ninja-build &&
+          pip3 install meson &&
+          wget $BITWUZLA_URL -nv -O bitwuzla.tar.gz &&
+          mkdir bitwuzla &&
+          tar xzf bitwuzla.tar.gz -C bitwuzla --strip-components=1 &&
+          pushd bitwuzla &&
+          ./configure.py &&
+          pushd build &&
+          ninja &&
+          popd &&
+          popd &&
+          cp bitwuzla/build/src/main/bitwuzla bin/ &&
+          sudo apt-get install -y build-essential git cmake bison flex libboost-all-dev libtinfo-dev python3 perl &&
+          wget $STP_URL -nv -O stp.tar.gz &&
+          mkdir stp &&
+          tar xzf stp.tar.gz -C stp --strip-components=1 &&
+          pushd stp &&
+          echo "LD_LIBRARY_PATH=$PWD/deps/cadical/build:$PWD/deps/cadiback/:$LD_LIBRARY_PATH" >> $GITHUB_ENV &&
+          ./scripts/deps/setup-gtest.sh &&
+          ./scripts/deps/setup-outputcheck.sh &&
+          ./scripts/deps/setup-cms.sh &&
+          ./scripts/deps/setup-minisat.sh &&
+          mkdir build &&
+          pushd build &&
+          cmake .. &&
+          cmake --build . &&
+          popd &&
+          popd &&
+          ln -s stp/build/stp bin/stp &&
+          sudo apt-get install -y gperf &&
+          wget $YICES2_URL -nv -O yices2.tar.gz &&
+          mkdir yices2 &&
+          tar xvf yices2.tar.gz -C yices2 --strip-components=1 &&
+          pushd yices2 &&
+          autoconf &&
+          ./configure --prefix=$PWD/out/ &&
+          make &&
+          make install &&
+          popd &&
+          cp yices2/out/bin/yices-smt2 bin/yices-smt2
+      - name: Install Rosette
+        run: raco pkg install --auto --name rosette
+      - name: Compile Rosette tests
+        run: raco make test/all-rosette-tests.rkt
+      - name: Run Rosette tests
+        run: raco test test/all-rosette-tests.rkt
+      - name: Compile SDSL tests
+        run: raco make test/all-sdsl-tests.rkt
+      - name: Run SDSL tests
+        run: raco test test/all-sdsl-tests.rkt

.travis.yml

@@ -1,52 +0,0 @@
-language: c
-sudo: false
-dist: bionic
-
-env:
-  global:
-    - RACKET_DIR=~/racket
-    - CVC4_URL="http://cvc4.cs.stanford.edu/downloads/builds/x86_64-linux-opt/cvc4-1.5-x86_64-linux-opt"
-    - BOOLECTOR_URL="https://github.com/Boolector/boolector/archive/3.2.1.tar.gz"
-  matrix:
-    - RACKET_VERSION=7.0  # Our minimum supported version
-    - RACKET_VERSION=RELEASE
-    - RACKET_VERSION=RELEASECS
-    - RACKET_VERSION=HEAD
-
-matrix:
-  allow_failures:
-    - env: RACKET_VERSION=HEAD
-    - env: RACKET_VERSION=RELEASECS
-  fast_finish: true
-
-before_install:
-  - git clone https://github.com/greghendershott/travis-racket.git
-  - cat travis-racket/install-racket.sh | bash # pipe to bash not sh!
-  - export PATH="${RACKET_DIR}/bin:${PATH}"
-  - if [ true ]; then
-      mkdir bin &&
-      wget $CVC4_URL -nv -O bin/cvc4 &&
-      chmod +x bin/cvc4 &&
-      wget $BOOLECTOR_URL -nv -O boolector.tar.gz &&
-      mkdir boolector &&
-      tar xzf boolector.tar.gz -C boolector --strip-components=1 &&
-      pushd boolector &&
-      ./contrib/setup-cadical.sh &&
-      ./contrib/setup-btor2tools.sh &&
-      ./configure.sh &&
-      cd build &&
-      make &&
-      popd &&
-      cp boolector/build/bin/boolector bin/ &&
-      rm -rf boolector*;
-    fi
-
-
-install:
-  - raco pkg install --auto
-
-script:
-  - time raco make test/all-rosette-tests.rkt
-  - raco test test/all-rosette-tests.rkt
-  - time raco make test/all-sdsl-tests.rkt
-  - raco test test/all-sdsl-tests.rkt

Dockerfile

@@ -0,0 +1,97 @@
+FROM alpine:3.15
+
+## ==========================  [ Install Racket ] =========================== ##
+
+## Define default Racket version and variant. The Racket version is of the form
+## <major>.<minor>. The variant can be "cs" (Chez Scheme), "bc" (Before Chez) or
+## "natipkg" (where external libraries are included in the Racket packages).
+##
+ARG RACKET_VERSION=8.4
+ARG RACKET_VARIANT=cs
+
+## Install Racket. We first install system dependencies: [gcompat] is needed for
+## Racket and [ncurses] is needed for the [xrepl] and [expeditor] packages,
+## providing the REPL. We then download the installer, run it with the right
+## parameters, then remove it. After that, all that remains is to set-up the
+## Racket packages and install [expeditor]. See later for a description of the
+## arguments to [raco pkg install].
+##
+RUN apk add --no-cache gcompat ncurses
+RUN wget "https://download.racket-lang.org/installers/${RACKET_VERSION}/racket-minimal-${RACKET_VERSION}-x86_64-linux-${RACKET_VARIANT}.sh"
+RUN echo 'yes\n1\n' | sh racket-minimal-${RACKET_VERSION}-x86_64-linux-${RACKET_VARIANT}.sh --create-dir --unix-style --dest /usr/
+RUN rm racket-minimal-${RACKET_VERSION}-x86_64-linux-${RACKET_VARIANT}.sh
+RUN raco setup --no-docs
+RUN raco pkg install -i --batch --auto --no-docs expeditor-lib
+
+## =================== [ Install Rosette's Dependencies ] =================== ##
+
+## Work on Rosette's installation within /usr/local. This directory will be
+## cleaned up later on so it could be anything.
+##
+WORKDIR /usr/local/rosette
+
+## Get all the info.rkt files. Trying to install Rosette based only on these
+## files would fail, but we can use them to only install dependencies.
+##
+COPY info.rkt         .
+COPY rosette/info.rkt rosette/
+
+## Install only Rosette's dependencies. We have to install the external
+## dependencies [libstdc++] and [libgcc] because Z3 needs them at runtime. As
+## for the Racket dependencies only, we achieve that in three steps:
+##
+##   1. We use [raco pkg install --no-setup] to download and register Rosette
+##      and all its dependencies without setting them up, that is without
+##      compiling them. At this point, the system is in an inconsistent state,
+##      where packages are registered but not actually present. The other flags
+##      are the following:
+##
+##        -i         install packages for all users
+##        --batch    disable interactive mode and suppress prompts
+##        --auto     download missing packages automatically
+##
+##   2. We use [raco pkg remove --no-setup] to unregister Rosette. This keeps
+##      the dependencies as registered. The system is still in an inconsistent
+##      state. See above for the flags.
+##
+##   3. We use [raco setup] to set up all the registered package. This brings
+##      the system back in a consistent state. Since Rosette's dependencies were
+##      registered but not Rosette itself, this achieves our goal. The flags are
+##      the following:
+##
+##        --fail-fast    fail on the first error encountered
+##        --no-docs      do not compile the documentations
+##
+RUN apk add --no-cache libstdc++ libgcc
+RUN raco pkg install -i --batch --auto --no-setup ../rosette
+RUN raco pkg remove  -i                --no-setup    rosette
+RUN raco setup       --fail-fast --no-docs
+
+## ========================== [ Install Rosette ] =========================== ##
+
+## Get all of Rosette; build and install it. The dependencies should all be
+## installed, so we can remove the --auto flag which will lead us to failure if
+## a dependency cannot be found. The additional flags are the following:
+##
+##   --copy    copy content to install path (instead of linking)
+##
+COPY . .
+RUN raco pkg install -i --batch --copy --no-docs ./rosette
+RUN rm -R /usr/local/rosette
+
+## ===================== [ Prepare Clean Entry Point ] ====================== ##
+
+## For further use of the image, we can start with user `rosette`, group
+## `rosette` in `/rosette` by default.
+##
+RUN addgroup rosette
+RUN adduser --system --shell /bin/false --disabled-password \
+    --home /rosette --ingroup rosette rosette
+RUN chown -R rosette:rosette /rosette
+USER rosette
+WORKDIR /rosette
+
+## Rosette files are simply Racket files using the Rosette library: the default
+## entry point of this image is therefore the Racket executable.
+##
+ENTRYPOINT ["/usr/bin/racket", "-I", "rosette"]

NOTES.md

@@ -1,5 +1,36 @@
 # Release Notes
 
+## Version 4.1
+
+This is a minor bug-fixing release.
+
+## Version 4.0
+
+This is a major release with significant changes to the language and the runtime.  Rosette 4.0 is *not backward compatible* with Rosette 3.x. But porting Rosette 3.x code to Rosette 4.0 should be straightforward for most applications.
+
+This release includes the following features:
+
+- Support for assumptions (see `assume`).
+- New symbolic evaluation core that tracks verification conditions (VCs) rather than path conditions and assertions.
+- New symbolic reflection constructs for working with VCs, including `vc`, `with-vc`, and `clear-vc!`.
+- New symbolic reflection facilities for managing symbolic `terms`, including the option of using a garbage-collected data structure.
+- Updated `verify`, `synthesize`, `solve`, and `optimize` queries.
+- New synthesis library with efficient support for grammar holes (see `define-grammar`).
+- New list and vector operators that use bitvectors instead of integers.
+- Updates to The Rosette Guide to document the new language in detail.
+
+The following features have been removed:
+
+- The `debug` query.
+- Reflection facilities for working with path conditions and assertions: `pc`, `with-asserts`, `with-asserts-only`, `clear-asserts!`, and `asserts`.
+- Support for CPLEX.
+
+## Version 3.2
+
+This release includes minor updates and a new [value destructuring library].
+
+[value destructuring library]: https://docs.racket-lang.org/rosette-guide/sec_utility-libs.html#%28part._.Value_.Destructuring_.Library%29
+
 ## Version 3.1
 
 This release includes bug fixes and updates Rosette to use the latest version of Z3 as its default SMT solver.

README.md

@@ -1,7 +1,7 @@
 The Rosette Language
 ====================
 
-[![Build Status](https://travis-ci.org/emina/rosette.svg?branch=master)](https://travis-ci.org/emina/rosette)
+[![Tests](https://github.com/emina/rosette/workflows/Tests/badge.svg)](https://github.com/emina/rosette/actions?query=workflow%3ATests)
 
 [Rosette](http://emina.github.io/rosette/) is a solver-aided programming language that extends [Racket](http://racket-lang.org) with language constructs for program synthesis, verification, and more. This repository includes the source code for Rosette, as well as several example solver-aided DSLs.
 
@@ -9,7 +9,7 @@ The Rosette Language
 
 The easiest way to install Rosette is from Racket's package manager:
 
-* Download and install Racket 7.0 or later from http://racket-lang.org
+* Download and install Racket 8.1 or later from http://racket-lang.org
 
 * Use Racket's `raco` tool to install Rosette:
 
@@ -19,7 +19,7 @@ The easiest way to install Rosette is from Racket's package manager:
 
 Alternatively, you can install Rosette from source:
 
-* Download and install Racket 7.0 or later from http://racket-lang.org
+* Download and install Racket 8.1 or later from http://racket-lang.org
 
 * Clone the rosette repository:
 
@@ -63,7 +63,7 @@ Alternatively, you can install Rosette from source:
 
 * The `rosette` language includes all of Racket.  This places the burden
   on the programmer to decide whether a given Racket construct (which
-  is not overriden by Rosette) is safe to use in a given context.
+  is not overridden by Rosette) is safe to use in a given context.
   Rosette provides no guarantees or checks for programs that use
   unsafe constructs.  In the best case, such a program will fail with
   an exception if a symbolic value flows to a construct that does not

info.rkt

@@ -5,7 +5,7 @@
 (define deps '("custom-load"
                "sandbox-lib"
                "scribble-lib"
-               ("racket" #:version "7.0")
+               ("racket" #:version "8.1")
                "r6rs-lib"
                "rfc6455"
                "net-lib"
@@ -28,4 +28,4 @@
 (define test-omit-paths (if (getenv "PLT_PKG_BUILD_SERVICE") 'all '()))
 
 (define pkg-desc "Rosette solver-aided host language")
-(define version "3.0")
+(define version "4.0")

rosette/base/adt/box.rkt

@@ -2,7 +2,7 @@
 
 (require (for-syntax racket/syntax "../core/lift.rkt") racket/provide 
          "../core/safe.rkt" "generic.rkt"
-         (only-in "../core/effects.rkt" apply!) 
+         (only-in "../core/store.rkt" store!)
          (only-in "../core/type.rkt" define-lifted-type type-cast)
          (only-in "../core/equality.rkt" @eq? @equal?)
          (only-in "../core/bool.rkt" instance-of? && ||)
@@ -40,12 +40,15 @@
     [(box v) v]
     [(union vs) (apply merge* (for/list ([gv vs]) (cons (car gv) (unbox (cdr gv)))))]))
 
+(define (box-ref x idx) (unbox x))          ; For the purpose of tracking mutations to the store, 
+(define (box-set! x idx v) (set-box! x v))  ; boxes are treated as 1-element vectors that ignore the index argument.
+
 (define (@set-box! b v)
   (match (type-cast @box? b 'set-box!)
     [(? box? x)                        
-     (apply! set-box! unbox x v)]
+     (store! x 0 v box-ref box-set!)]
     [(union vs)
      (for ([gv vs])
        (let ([x (cdr gv)])
-         (apply! set-box! unbox x (merge (car gv) v (unbox x)))))]))
+         (store! x 0 (merge (car gv) v (unbox x)) box-ref box-set!)))]))
      

rosette/base/adt/bvseq.rkt

@@ -0,0 +1,161 @@
+#lang racket
+
+(require
+  (only-in "list.rkt" @list?)
+  (only-in "vector.rkt" @vector? @vector-set!)
+  (only-in "../core/lift.rkt" lift-id)
+  (only-in "../core/forall.rkt" for/all for*/all)
+  (only-in "../core/term.rkt" get-type type-cast term?)
+   "../core/union.rkt"
+  "../core/bitvector.rkt"
+  "../core/merge.rkt"
+  "../core/safe.rkt")
+
+(provide @list-ref-bv @list-set-bv
+         @take-bv @take-right-bv
+         @drop-bv @drop-right-bv @list-tail-bv
+         @split-at-bv @split-at-right-bv
+         @length-bv
+         @vector-ref-bv @vector-set!-bv @vector-length-bv)
+
+(define (bv-lit-or-term? v)
+  (or (bv? v) (and (term? v) (bitvector? (get-type v)))))
+
+(define-syntax-rule (lift-body #:with (id xs idx seq-length) #:type t #:max n #:body body ...)
+  (let* ([t   (get-type idx)]
+         [2^k (expt 2 (bitvector-size t))]
+         [sz  (seq-length xs)]
+         [n   (min sz 2^k)])
+    (when (>= (- 2^k 1) sz)
+      (assert (@bvult idx  (@integer->bitvector sz t))
+              (index-too-large-error 'id xs idx)))
+    body ...))
+
+(define-syntax (define-lift-bv stx)
+  (syntax-case stx ()
+    [(_ (proc-bv xs idx arg ...) @seq? seq?)
+     #`(define-lift-bv #,(lift-id #'proc-bv) (proc-bv xs idx arg ...) @seq? seq?)]
+    [(_ @proc-bv (proc-bv xs idx arg ...) @seq? seq?)
+     #'(define (@proc-bv xs idx arg ...)
+         (if (and (seq? xs) (bv-lit-or-term? idx))
+             (proc-bv xs idx arg ...)
+             (match* ((type-cast @seq? xs 'proc-bv)
+                      (bvcoerce idx 'proc-bv))
+               [((? seq? xs) (? bv-lit-or-term? idx))
+                (proc-bv xs idx arg ...)]
+               [(xs idx)
+                (for*/all ([xs xs][idx idx])
+                  (proc-bv xs idx arg ...))])))]))
+
+(define-syntax (define-length-bv stx)
+  (syntax-case stx ()
+    [(_ length-bv @seq? seq?  seq-length)
+     #`(begin
+         (define (length-bv xs t) ; (-> seq bitvector? @bv?)
+           (@integer->bitvector (seq-length xs) t))
+         (define (#,(lift-id #'length-bv) xs t)
+           (match (type-cast @seq? xs 'length-bv)
+             [(? seq? xs) (length-bv xs t)]
+             [xs (for/all ([xs xs]) (length-bv xs t))])))]))
+
+(define-syntax-rule (define-ref-bv ref-bv @seq? seq? seq-ref seq-length)
+  (begin
+    (define (ref-bv xs idx) ; (-> type? bv-lit-or-term? any/c)
+      (if (bv? idx)
+          (seq-ref xs (@bitvector->natural idx))
+          (lift-body
+           #:with (ref-bv xs idx seq-length)
+           #:type t
+           #:max  n
+           #:body 
+            (apply
+             merge*
+             (for/list ([x xs] [i n])
+               (cons (@bveq (bv i t) idx) x))))))
+
+    (define-lift-bv (ref-bv xs idx) @seq? seq?)))
+
+; ---- list bv procedures ---- ;
+
+(define-length-bv length-bv @list? list? length)
+(define-ref-bv list-ref-bv @list? list? list-ref length)
+
+(define (list-set-bv xs idx v)
+  (if (bv? idx)
+      (list-set xs (@bitvector->natural idx) v)
+      (lift-body
+       #:with (list-set-bv xs idx length)
+       #:type t
+       #:max  n
+       #:body (for/list ([(x i) (in-indexed xs)])
+                (if (< i n)
+                    (merge (@bveq (bv i t) idx) v x)
+                    x)))))
+
+(define-lift-bv (list-set-bv xs idx v) @list? list?)
+
+(define (pair-length ps bound)
+  (if (list? ps)
+      (min (length ps) bound)
+      (let loop ([ps ps] [acc 0])
+        (if (and (pair? ps) (< acc bound))
+            (loop (cdr ps) (add1 acc))
+            acc))))
+                     
+(define-syntax (define-get-bv stx)
+  (syntax-case stx ()
+    [(_ get-bv seq-get)
+     #`(begin
+         (define (get-bv xs idx) 
+           (if (bv? idx)
+               (seq-get xs (@bitvector->natural idx))
+               (let* ([t   (get-type idx)]
+                      [2^k (expt 2 (bitvector-size t))]
+                      [sz  (pair-length xs (sub1 2^k))])
+                 (when (> (- 2^k 1) sz)
+                   (assert (@bvule idx  (@integer->bitvector sz t))
+                           (index-too-large-error 'id xs idx)))
+                 (apply
+                  merge*
+                  (for/list ([i (add1 sz)])
+                    (cons (@bveq (bv i t) idx)
+                          
+                          (seq-get xs i)))))))
+         (define (#,(lift-id #'get-bv) xs idx)
+           (if (and (not (union? xs)) (bv-lit-or-term? idx))
+               (get-bv xs idx)
+               (match* (xs (bvcoerce idx 'get-bv))
+                 [((not (? union? xs)) (? bv-lit-or-term? idx))
+                  (get-bv xs idx)]
+                 [(xs idx)
+                  (for*/all ([xs xs][idx idx])
+                    (get-bv xs idx))]))))]))
+
+(define-get-bv take-bv take)
+(define-get-bv take-right-bv take-right)
+(define-get-bv drop-bv drop)      
+(define-get-bv drop-right-bv drop-right)
+(define-get-bv list-tail-bv list-tail)
+
+(define (@split-at-bv xs idx)
+  (values (@take-bv xs idx) (@drop-bv xs idx)))
+
+(define (@split-at-right-bv xs idx)
+  (values (@drop-right-bv xs idx) (@take-right-bv xs idx)))
+
+; ---- vector bv procedures ---- ;
+
+(define (vector-set!-bv xs idx v)
+  (if (bv? idx)
+      (@vector-set! xs (@bitvector->natural idx) v)
+      (lift-body
+       #:with (vector-set!-bv xs idx vector-length)
+       #:type t
+       #:max  n
+       #:body 
+       (for ([x xs] [i n])
+         (@vector-set! xs i (merge (@bveq (bv i t) idx) v x))))))
+
+(define-length-bv vector-length-bv @vector? vector? vector-length)
+(define-ref-bv vector-ref-bv @vector? vector? vector-ref vector-length)
+(define-lift-bv (vector-set!-bv xs idx v) @vector? vector?)

rosette/base/adt/list.rkt

@@ -99,7 +99,7 @@
 
 ;; List Iteration
 (define (bad-lengths-error name . args)
-  (thunk (error name "all lists must have same size\n  given: ~a" (map ~.a args))))
+  (argument-error name "lists of equal length" (map ~.a args)))
 
 (define (lengths xs)
   (match xs
@@ -282,20 +282,6 @@
                                 (@+ rank (@if (ranked>? (key-of x) i (key-of y) j) 1 0))))])
                 (for/list ([i len])
                   (for/fold ([v 0]) ([x xs] [r ranks]) (merge (@= i r) x v))))]))
-              #|(define vars (for/list ([i (in-range len)]) (define-symbolic* rank @integer?) rank))
-              (for ([v vars])
-                (assert (@<= 0 v))
-                (assert (@< v len)))
-              (let loop ([vars vars] [xs l])
-                (match* (vars xs)
-                  [((or (list) (list _)) _) (void)]
-                  [((list v v-rest ...) (list x x-rest ...)) 
-                   (let ([key (key-of x)])
-                     (for ([v1 v-rest] [x1 x-rest])
-                       (assert (@if (less? key (key-of x1)) (@< v v1) (@< v1 v)))))
-                   (loop v-rest x-rest)]))
-              (for/list ([i (in-range (length l))])
-                (apply merge* (for/list ([x l] [v vars]) (cons (@= v i) x))))]))|#
      (define (fast-sort less? getkey cache-keys? xs)
        (sort xs less? #:key getkey #:cache-keys? cache-keys?))
      (define/lift/applicator fast-sort less? getkey cache-keys? xs)
@@ -443,8 +429,8 @@
 
 
 (define @apply 
-  (case-lambda [() (error 'apply "arity mismatch;\n  expected: at least 2\n  given: 0")]
-               [(proc) (error 'apply "arity mismatch;\n  expected: at least 2\n  given: 1")]
+  (case-lambda [() (assert #f (argument-error 'apply "at least 2 arguments" 0))]
+               [(proc) (assert #f (argument-error 'apply "at least 2 arguments" 1))]
                [(proc xs) (lift/apply/higher-order apply proc xs : list? -> @list?)]
                [(proc x0 xs) (lift/apply/higher-order apply proc x0 xs : list? -> @list?)]
                [(proc x0 x1 xs) (lift/apply/higher-order apply proc x0 x1 xs : list? -> @list?)]
@@ -524,29 +510,26 @@
            (merge** ys (insert* _ i v))]))))
            
 (splicing-local
-    [(define (replace xs i v)
-       (let-values ([(left right) (split-at xs i)])
-         (append left (cons v (cdr right)))))
-     (define (replace* xs i v)
-       (apply merge* (for/list ([(x idx) (in-indexed xs)])
-                     (cons (@= i idx) (replace xs idx v)))))]
-  (define (@replace xs i v)
-    (or (and (list? xs) (number? i) (replace xs i v))
-        (match* ((type-cast @list? xs 'replace) (type-cast @integer? i 'replace))
-          [((? list? xs) (? number? i)) (replace xs i v)]
+    [(define ($list-set xs i v)
+       (for/list ([(x idx) (in-indexed xs)])
+         (merge (@= i idx) v x)))]
+  (define (@list-set xs i v)
+    (or (and (list? xs) (number? i) (list-set xs i v))
+        (match* ((type-cast @list? xs 'list-set) (type-cast @integer? i 'list-set))
+          [((? list? xs) (? number? i)) (list-set xs i v)]
           [((? list? xs) i) 
-           (assert-bound [0 @<= i @< (length xs)] 'replace)
-           (replace* xs i v)]
+           (assert-bound [0 @<= i @< (length xs)] 'list-set)
+           ($list-set xs i v)]
           [((union ys) (? number? i))
-           (assert-bound [0 <= i] 'replace)
+           (assert-bound [0 <= i] 'list-set)
            (apply merge* (assert-some 
                         (for/list ([y ys] #:when (< i (length (cdr y))))
-                          (cons (car y) (replace (cdr y) i v)))
+                          (cons (car y) (list-set (cdr y) i v)))
                         #:unless (length ys)
-                        (index-too-large-error 'replace xs i)))]
+                        (index-too-large-error 'list-set xs i)))]
           [((union ys) i)
-           (assert-bound [0 @<= i @< (@length xs)] 'replace)
-           (merge** ys (replace* _ i v))]))))
+           (assert-bound [0 @<= i @< (@length xs)] 'list-set)
+           (merge** ys ($list-set _ i v))]))))
            
 
 #|

rosette/base/adt/vector.rkt

@@ -6,7 +6,7 @@
          "../core/safe.rkt" "../core/lift.rkt" "seq.rkt" "../core/forall.rkt" "generic.rkt"
          (only-in "list.rkt" @list?)
          (only-in "../form/control.rkt" @when)
-         (only-in "../core/effects.rkt" apply!) 
+         (only-in "../core/store.rkt" store!)
          (only-in "../core/term.rkt" define-lifted-type @any/c type-cast)
          (only-in "../core/equality.rkt" @eq? @equal?)
          (only-in "../core/bool.rkt" instance-of? && ||)
@@ -58,16 +58,15 @@
 
 (define (merge-set! vec idx val guard)
   (for ([i (in-range (vector-length vec))])
-    (apply! vector-set! vector-ref 
-            vec i (merge (&& guard (@= i idx)) val (vector-ref vec i)))))
+    (store! vec i (merge (&& guard (@= i idx)) val (vector-ref vec i)) vector-ref vector-set!)))
 
 (define (@vector-set! vec idx val)
   ;(printf "vector-set! ~a ~a ~a\n" (eq-hash-code vec) idx val)
   (if (and (vector? vec) (number? idx))
-      (apply! vector-set! vector-ref vec idx val)
+      (store! vec idx val vector-ref vector-set!)
       (match* ((type-cast @vector? vec 'vector-set!) (type-cast @integer? idx 'vector-set!))
         [((? vector? vs) (? number? idx))
-         (apply! vector-set! vector-ref vs idx val)]
+         (store! vs idx val vector-ref vector-set!)]
         [((? vector? vs) idx)
          (assert-bound [0 @<= idx @< (vector-length vs)] 'vector-set!)
          (merge-set! vs idx val #t)]
@@ -76,8 +75,7 @@
          (assert-|| (for/list ([v vs] #:when (< idx (vector-length (cdr v))))
                       (let ([guard (car v)]
                             [vec (cdr v)])
-                        (apply! vector-set! vector-ref 
-                                vec idx (merge guard val (vector-ref vec idx)))
+                        (store! vec idx (merge guard val (vector-ref vec idx)) vector-ref vector-set!)
                         guard))
                     #:unless (length vs)
                     (index-too-large-error 'vector-set! vec idx))]
@@ -90,14 +88,13 @@
   (match (type-cast @vector? vec 'vector-fill!)
     [(? vector? vs)
      (for ([i (in-range (vector-length vs))])
-       (apply! vector-set! vector-ref vs i val))]
+       (store! vs i val vector-ref vector-set!))]
     [(union vs)
      (for ([v vs])
        (let ([guard (car v)]
              [vec (cdr v)])
          (for ([i (in-range (vector-length vec))])
-           (apply! vector-set! vector-ref 
-                   vec i (merge guard val (vector-ref vec i))))))]))
+           (store! vec i (merge guard val (vector-ref vec i)) vector-ref vector-set!))))]))
 
 ; Vector copy helper procedure.  Requires dest and src to be 
 ; vectors (rather than unions of vectors), and dest-start, src-start

rosette/base/base.rkt

@@ -7,17 +7,18 @@
   "core/bool.rkt" "core/real.rkt" "core/numerics.rkt" "core/bitvector.rkt" "core/bvlib.rkt"
   "core/function.rkt"
   "core/procedure.rkt" "core/equality.rkt" "core/distinct.rkt" "core/reflect.rkt"  
-  "adt/box.rkt" "adt/list.rkt" "adt/vector.rkt" 
+  "adt/box.rkt" "adt/list.rkt" "adt/vector.rkt" "adt/bvseq.rkt"
   "struct/struct.rkt" "struct/generics.rkt"
-  "form/state.rkt" "form/define.rkt" "form/control.rkt" "form/module.rkt" "form/app.rkt") 
+  "form/define.rkt" "form/control.rkt" "form/module.rkt" "form/app.rkt") 
 
 (provide
   (rename-out [@|| ||]) ; The character sequence || does not play nicely with the filtered-out form.
   (filtered-out drop@ 
     (combine-out
      ; core/bool.rkt
-     pc with-asserts with-asserts-only asserts clear-asserts!
-     @assert @boolean? @false? @! @&& @=> @<=> @forall @exists
+     vc with-vc clear-vc! vc? vc-true? vc-true vc-assumes vc-asserts
+     @assert @assume
+     @boolean? @false? @! @&& @=> @<=> @forall @exists
      ; core/real.rkt
      @integer? @real? @= @< @<= @>= @> 
      @+ @* @- @/ @quotient @remainder @modulo @abs
@@ -32,6 +33,7 @@
      @bvnot @bvor @bvand @bvxor @bvshl @bvlshr @bvashr
      @bvneg @bvadd @bvsub @bvmul @bvudiv @bvsdiv @bvurem @bvsrem @bvsmod
      @concat @extract @sign-extend @zero-extend 
+     @z3_ext_rotate_left @z3_ext_rotate_right
      @integer->bitvector @bitvector->integer @bitvector->natural
      ; core/bvlib.rkt
      bit lsb msb bvzero? bvadd1 bvsub1
@@ -46,11 +48,14 @@
      @eq? @equal?
      ; core/reflect.rkt
      symbolics type? solvable? @any/c type-of type-cast for/all for*/all
+     symbolic? concrete?
      term? constant? expression? 
      term expression constant term-type
-     term=? term->datum clear-terms! term-cache
+     term=? term->datum
+     terms terms-count terms-ref with-terms clear-terms! gc-terms!
      union? union union-contents union-guards union-values
      union-filter in-union in-union* in-union-guards in-union-values
+     result? result-value result-state normal normal? failed failed?
      ; adt/box.rkt
      @box @box-immutable @box? @unbox @set-box!
      ; adt/list.rkt : Pair Constructors and Selectors
@@ -74,9 +79,9 @@
      @take @drop @split-at @take-right @drop-right @split-at-right
      @add-between @append* @flatten @remove-duplicates 
      @filter-map @count @partition @append-map @filter-not @shuffle 
-     @argmin @argmax 
+     @argmin @argmax @list-set
      ; adt/list.rkt : Non-Standard Functions
-     @insert @replace
+     @insert 
      ; adt/vector.rkt : Basic Functions
      @vector? @vector @vector-immutable 
      @vector-length @vector-ref @vector-set! @vector->list @list->vector @vector->immutable-vector 
@@ -85,12 +90,16 @@
      @vector-append
      ; adt/procedure.rkt
      @procedure? @apply @procedure-rename @negate @void?
+     ; adt/bvseq.rkt
+     @list-ref-bv @list-set-bv @length-bv
+     @take-bv @take-right-bv
+     @drop-bv @drop-right-bv @list-tail-bv
+     @split-at-bv @split-at-right-bv
+     @vector-ref-bv @vector-set!-bv @vector-length-bv
      ; struct/struct.rkt
      struct struct-field-index define/generic define-struct
      ; struct/generics.rkt
      @define-generics @make-struct-type-property
-     ; form/state.rkt
-     current-oracle oracle oracle? 
      ; form/define.rkt
      define-symbolic define-symbolic*
      ; form/control.rkt
@@ -164,7 +173,7 @@
  expand-syntax-to-top-form
  ; input and output
  read read-syntax
- write display print displayln fprintf printf eprintf format newline
+ write display print writeln displayln println fprintf printf eprintf format newline
  pretty-print pretty-write pretty-display pretty-format 
  call-with-input-file
  current-input-port current-output-port current-error-port eof

rosette/base/core/bitvector.rkt

@@ -14,21 +14,19 @@
  @bvnot @bvor @bvand @bvxor @bvshl @bvlshr @bvashr
  @bvneg @bvadd @bvsub @bvmul @bvudiv @bvsdiv @bvurem @bvsrem @bvsmod
  @concat @extract @sign-extend @zero-extend
+ @z3_ext_rotate_left @z3_ext_rotate_right
  @integer->bitvector @bitvector->integer @bitvector->natural)
 
 ;; ----------------- Bitvector Types ----------------- ;; 
 
 ; Cache of all bitvector types constructed so far, mapping sizes to types.
-(define bitvector-types (make-hash))
+(define bitvector-types (make-hasheq))
 
 ; Returns the bitvector type of the given size.
 (define (bitvector-type size)
-  (unless (exact-positive-integer? size)
-    (raise-argument-error 'bitvector "exact-positive-integer?" size))
-  (or (hash-ref bitvector-types size #f)
-      (let ([t (bitvector size)]) 
-        (hash-set! bitvector-types size t)
-        t)))
+  (assert (and (exact-positive-integer? size) (fixnum? size))
+          (argument-error 'bitvector "(and/c exact-positive-integer? fixnum?)" size))
+  (hash-ref! bitvector-types size (λ () (bitvector size))))
 
 ; Represents a bitvector type.
 (struct bitvector (size)
@@ -53,9 +51,9 @@
        [(bv _ (== self)) v]
        [(term _ (== self)) v]
        [(union (list _ ... (cons gt (and (? typed? vt) (app get-type (== self)))) _ ...) _) 
-        (assert gt (thunk (error caller "expected ~a, given ~.a" self v)))
+        (assert gt (type-error caller self v))
         vt]
-       [_ (assert #f (thunk (error caller "expected ~a, given ~.a" self v)))]))
+       [_ (assert #f (type-error caller self v))]))
    (define (type-eq? self u v)        (@bveq u v))
    (define (type-equal? self u v)     (@bveq u v))
    (define (type-compress self f? ps) (generic-merge* ps))
@@ -88,6 +86,7 @@
   #:transparent
   #:methods gen:typed
   [(define (get-type self) (bv-type self))]
+  #:property prop:custom-print-quotable 'never
   #:methods gen:custom-write
   [(define (write-proc self port mode)
      (match self
@@ -120,14 +119,14 @@
 ; be either an exact-positive-integer? or a bitvector type. 
 ; The number may be a real, non-infinite, non-NaN concrete value.  
 (define (make-bv val precision)
-  (unless (and (real? val) (not (infinite? val)) (not (nan? val)))
-    (raise-arguments-error 'bv "expected a real, non-infinite, non-NaN number" "value" val))
+  (assert (and (real? val) (not (infinite? val)) (not (nan? val)))
+          (arguments-error 'bv "expected a real, non-infinite, non-NaN number" "value" val))
   (cond [(exact-positive-integer? precision) 
          (bv (sfinitize val precision) (bitvector-type precision))]
         [(bitvector? precision) 
          (bv (sfinitize val (bitvector-size precision)) precision)]
         [else 
-         (raise-arguments-error 'bv "exact-positive-integer? or bitvector? type" "precision" precision)]))
+         (assert #f (arguments-error 'bv "exact-positive-integer? or bitvector? type" "precision" precision))]))
 
 ; Pattern matching for bitvector literals.
 (define-match-expander @bv
@@ -340,6 +339,13 @@
      (ite (bveq (bv 0 t) (bvand x (bv (bvsmin t) t))) (bv 0 t) (bv -1 t))]
     [(_ _) (expression @bvashr x y)]))
 
+
+(define (z3_ext_rotate_left x y)
+  (expression @z3_ext_rotate_left x y))
+
+(define (z3_ext_rotate_right x y)
+  (expression @z3_ext_rotate_right x y))
+
 (define-lifted-operator @bvnot bvnot T*->T)
 (define-lifted-operator @bvand bvand T*->T)
 (define-lifted-operator @bvor bvor T*->T)
@@ -347,6 +353,8 @@
 (define-lifted-operator @bvshl bvshl T*->T)
 (define-lifted-operator @bvlshr bvlshr T*->T)
 (define-lifted-operator @bvashr bvashr T*->T)
+(define-lifted-operator @z3_ext_rotate_left z3_ext_rotate_left T*->T)
+(define-lifted-operator @z3_ext_rotate_right z3_ext_rotate_right T*->T)
 
 ;; ----------------- Simplification ruules for bitwise operators ----------------- ;;
 
@@ -595,7 +603,7 @@
                       _))
      (if (< i size)
          (extract i j a)
-         (expression @bvop a (bitvector (add1 i))))]
+         (expression @bvop a (bitvector-type (add1 i))))]
     [(_ _ _) (expression @extract i j x)]))
         
 (define-operator @extract

rosette/base/core/bool.rkt

@@ -1,13 +1,17 @@
 #lang racket
 
-(require "term.rkt" "union.rkt" "exn.rkt")
+(require "term.rkt" "union.rkt" "exn.rkt" "result.rkt" "reporter.rkt")
 
-(provide @boolean? @false? 
+(provide
+ ;; ---- lifted boolean? operations ---- ;;
+ @boolean? @false? @true?
  ! && || => <=> @! @&& @|| @=> @<=> @exists @forall
-         and-&& or-|| instance-of?
-         @assert pc with-asserts with-asserts-only 
-         (rename-out [export-asserts asserts]) clear-asserts!
-         T*->boolean?)
+ and-&& or-|| instance-of? T*->boolean?
+ ;; ---- VC generation ---- ;;       
+ @assert @assume $assert $assume
+ (rename-out [get-vc vc]) clear-vc! merge-vc! with-vc 
+ vc? vc-assumes vc-asserts
+ vc-true vc-true?)
 
 ;; ----------------- Boolean type ----------------- ;; 
 (define-lifted-type @boolean? 
@@ -22,9 +26,9 @@
        [(? boolean?) v]
        [(term _ (== self)) v]
        [(union : [g (and (or (? boolean?) (term _ (== self))) u)] _ ...)
-        (@assert g (thunk (raise-argument-error caller "expected a boolean?" v)))
+        ($assert g (argument-error caller "boolean?" v))
         u]
-       [_  (@assert #f (thunk (raise-argument-error caller "expected a boolean?" v)))]))
+       [_  ($assert #f (argument-error caller "boolean?" v))]))
    (define (type-compress self force? ps)
      (match ps
        [(list _) ps]
@@ -68,12 +72,9 @@
           [((list (constant _ (? primitive-solvable?)) (... ...)) body)
            ($op @vars body)]
           [(_ _)
-           (@assert
+           ($assert
             #f
-            (thunk
-             (raise-argument-error
-              '$op
-              "expected a list of symbolic constants of primitive solvable types" @vars)))])))))
+            (argument-error '$op "list of symbolic constants of primitive solvable types" @vars))])))))
 
 ;; ----------------- Basic boolean operators ----------------- ;; 
 (define (! x)
@@ -85,9 +86,26 @@
 (define && (logical-connective @&& @|| #t #f))
 (define || (logical-connective @|| @&& #f #t))
 
-(define (=> x y) (|| (! x) y))
+(define (=> x y) ; (|| (! x) y))
+  (cond
+    [(equal? x y) #t]
+    [(eq? x #f) #t]
+    [(eq? y #t) #t]
+    [(eq? x #t) y]
+    [(eq? y #f) (! x)]
+    [(cancel? x y) y]
+    [else
+     (match y
+       [(expression (== @||) _ ... (== x) _ ...) #t]
+       [(expression (== @&&) (== x) b) (=> x b)]
+       [(expression (== @&&) b (== x)) (=> x b)]
+       [(expression (== @&&) (expression (== @||) _ ... (== x) _ ...) b) (=> x b)]
+       [(expression (== @&&) b (expression (== @||) _ ... (== x) _ ...)) (=> x b)]
+       [(expression (== @<=>) (== x) b) (=> x b)]
+       [(expression (== @<=>) b (== x)) (=> x b)]
+       [_ (|| (! x) y)])]))
        
-(define (<=> x y) ;(|| (&& x y) (&& (! x) (! y))))))
+(define (<=> x y) 
   (cond [(equal? x y) #t]
         [(boolean? x) (if x y (! y))]
         [(boolean? y) (if y x (! x))]
@@ -114,12 +132,15 @@
          [_ (loop (cdr xs))]))]
     [_ #f]))
 
+(define (@true? v)
+  (or (eq? #t v) (! (@false? v))))
+
 (define-quantifier exists @exists)
 (define-quantifier forall @forall)
 
 
        
-;; ----------------- Additional operators ----------------- ;; 
+;; ----------------- Additional operators and utilities ----------------- ;;
 (define-syntax and-&&
   (syntax-rules ()
     [(_) #t]
@@ -143,6 +164,15 @@
                      (and (union? v) (apply || (for/list ([g (in-union-guards v symbolic-type)]) g))))]
                 [_ #f]))
 
+(define ⊥ (void))
+
+(define-syntax first-term-or-bool
+  (syntax-rules ()
+    [(_ e) e]
+    [(_ e0 e ...) (let ([v e0])
+                    (if (void? v)
+                        (first-term-or-bool e ...)
+                        v))]))
 
 ;; ----------------- Partial evaluation rules for ∀ and ∃ ----------------- ;;
 
@@ -165,7 +195,7 @@
        [((== !iden) _) !iden]
        [(_ (== !iden)) !iden]
        [(_ _)
-        (first-value 
+        (first-term-or-bool 
          (simplify-connective op co !iden x y)
          (if (term<? x y)  (expression op x y) (expression op y x)))])]
     [xs 
@@ -176,27 +206,19 @@
               [(list x) x]
               [ys (apply expression op (sort ys term<?))])])]))
        
-(define ⊥ (void))
-(define-syntax first-value
-  (syntax-rules ()
-    [(_ e) e]
-    [(_ e0 e ...) (let ([v e0])
-                    (if (void? v)
-                        (first-value e ...)
-                        v))]))
-
 (define (simplify-connective op co !iden x y)
   (match* (x y)
     [(_ (== x)) x]
     [((? expression?) (? expression?))
-     (first-value
+     (first-term-or-bool
+      (if (term<? y x)
           (simplify-connective:expr/any op co !iden x y)
-      (simplify-connective:expr/any op co !iden y x)
+          (simplify-connective:expr/any op co !iden y x))
       (simplify-connective:expr/expr op co !iden x y))]
     [((? expression?) _)
-     (simplify-connective:expr/any op co !iden x y)]
+     (if (term<? y x) (simplify-connective:expr/any op co !iden x y) ⊥)]
     [(_ (? expression?))
-     (simplify-connective:expr/any op co !iden y x)]
+     (if (term<? x y) (simplify-connective:expr/any op co !iden y x) ⊥)]
     [(_ _) ⊥]))
       
 (define (simplify-connective:expr/any op co !iden x y)
@@ -206,21 +228,13 @@
     [(expression (== op) _ ... (== y) _ ...) x]
     [(expression (== op) _ ... (expression (== @!) (== y)) _ ...) !iden]
     [(expression (== @!) (expression (== co) _ ... (== y) _ ...)) !iden]
-    [(expression (== @!) (expression (== co) _ ... (expression (== @!) (== y)) _ ...)) x]
-    [(expression (== @!) (expression (== op) _ ... (expression (== @!) (== y)) _ ...)) y]
-    [(expression (== @!) a) 
-     (match y 
-       [(expression (== op) _ ... (== a) _ ...) !iden]
-       [_ ⊥])]
     [_  ⊥]))
 
-; Applies the following simplification rules symmetrically:
-; (1) (op (op a1 ... an) (op ai ... aj)) ==> (op a1 ... an)
-; (2) (op (op a1 ... ai ... an) (op b1 ... (neg ai) ... bn) ==> !iden
-; (3) (op (co a1 ... an) (co ai ... aj)) ==> (co ai ... aj)
-; Returns ⊥ if none of the rules applicable; otherwise returns the simplified result.
+
 (define (simplify-connective:expr/expr op co !iden a b)       
   (match* (a b)
+    [((expression (== op) _ ... x _ ...) (expression (== @!) x)) !iden]
+    [((expression (== @!) x) (expression (== op) _ ... x _ ...)) !iden]
     [((expression (== op) xs ...) (expression (== op) ys ...))
      (cond [(sublist? xs ys) b]
            [(sublist? ys xs) a]
@@ -230,6 +244,12 @@
      (cond [(sublist? xs ys) a]
            [(sublist? ys xs) b]
            [else ⊥])]
+    [((expression (== op) xs ...) (expression (== co) ys ...))
+     (cond [(for*/or ([x xs][y ys]) (equal? x y)) a]
+           [else ⊥])]
+    [((expression (== co) xs ...) (expression (== op) ys ...))
+     (cond [(for*/or ([y ys][x xs]) (equal? x y)) b]
+           [else ⊥])]
     [(_ _) ⊥]))
     
 (define (simplify-fp op co !iden xs)
@@ -262,54 +282,196 @@
     [(_ _) #f]))
 
 
-;; ----------------- Assertions and path condition ----------------- ;; 
-(define (export-asserts) (remove-duplicates (asserts)))
+;; ----------------- VC generation ----------------- ;;
 
-(define (clear-asserts!)  (asserts '()))
+; A verification condition (VC) consists of two @boolean?
+; values representing assumptions and assertions issued
+; during execution. A VC is legal if at least one of its
+; constituent fields is true under all models.
 
-(define asserts 
+(struct vc (assumes asserts) #:transparent)
+
+; The true verification condition.
+(define vc-true (vc #t #t))
+
+(define (vc-true? s) (equal? s vc-true))
+
+; Returns (vc (s.assumes && (s.asserts => g)) s.asserts). 
+(define (assuming s g)  ; g must be a symbolic or concrete boolean
+  (vc (&& (vc-assumes s) (=> (vc-asserts s) g)) (vc-asserts s)))
+
+; Returns (vc s.assumes (s.asserts && (s.assumes => g))). 
+(define (asserting s g) ; g must be a symbolic or concrete boolean 
+  (vc (vc-assumes s) (&& (vc-asserts s) (=> (vc-assumes s) g))))
+
+; The current-vc parameter keeps track of the current verification condition,
+; which is an instance of vc?. The default value for this parameter is vc-true.
+(define current-vc
   (make-parameter
-   '()
-   (match-lambda [(? list? xs) xs]
-                 [x (if (eq? x #t) (asserts) (cons x (asserts)))])))
+   vc-true
+   (lambda (v) (unless (vc? v) (raise-argument-error 'vc "vc?" v)) v)))
 
-(define pc 
-  (make-parameter 
-   #t
-   (lambda (new-pc) 
-     (or (boolean? new-pc) 
-         (and (term? new-pc) (equal? @boolean? (term-type new-pc)))
-         (error 'pc "expected a boolean path condition, given a ~s" (type-of new-pc)))
-     (or (&& (pc) new-pc)
-         (raise-exn:fail:rosette:infeasible)))))
+; Returns the current vc, without exposing the parameter outside the module. 
+(define (get-vc) (current-vc))
 
+; Clears the current vc by setting it to the true spec.
+(define (clear-vc!) (current-vc vc-true))
+
+; Returns #t if x && (g => y) is equivalent to x according to the embedded
+; rewrite rules. Otherwise returns #f.
+(define (merge-absorbs? x g y)
+  (match y
+    [(== x) #t]                                                                ; x && (g => x)  
+    [(expression (== @&&) (== x) (== g)) #t]                                   ; x && (g => (x && g)) 
+    [(expression (== @&&) (== g) (== x)) #t]                                   ; x && (g => (x && g))  
+    [(expression (== @&&) (== x) (expression (== @||) _ ... (== g) _ ...)) #t] ; x && (g => (x && (_ => g))) 
+    [(expression (== @&&) (expression (== @||) _ ... (== g) _ ...) (== x)) #t] ; x && (g => ((_ => g) && x))  
+    [_ #f]))
+  
+; Returns (field x) && (gs[0] => (field ys[0])) ... && (gs[n-1] => (field gs[n-1])).
+(define (merge-field field x gs ys)
+  (define xf (field x))
+  (apply && xf
+    (for*/list ([(g y) (in-parallel gs ys)]
+                [yf    (in-value (field y))]
+                #:unless (merge-absorbs? xf g yf))
+      (=> g yf))))
+
+;; Returns (field x) && (gs[0] => (field ys[0])) ... && (gs[n-1] => (field gs[n-1])).
+;; Assumes that ys[i] => x for all i, and at most one gs evaluates to true in any model.
+;(define (merge-field field x gs ys)
+;  (define xf (field x))
+;  (define gs=>ys
+;    (for*/list ([(g y) (in-parallel gs ys)]
+;                [yf    (in-value (field y))]
+;                #:unless (merge-absorbs? xf g yf))
+;      (=> g yf)))
+;  (match gs=>ys
+;    [(list) xf]
+;    [(list gy) (&& xf gy)]
+;    [(or (list (expression (== @||) _ ... g _ ...) (expression (== @||) _ ... (expression (== @!) g) _ ...))
+;         (list (expression (== @||) _ ... (expression (== @!) g) _ ...) (expression (== @||) _ ... g _ ...)))
+;     (apply && gs=>ys)]
+;    [_ (apply && xf gs=>ys)]))
+
+; Takes as input a list of n guards and n vcs and sets the current vc
+; to (current-vc) && (vc-guard guard1 vc1) && ... && (vc-guard guardn vcn).
+; Then, it checks if either the assumes or the asserts of the resulting vc
+; are false? and if so, throws either an exn:fail:svm:assume? or
+; exn:fail:svm:assert? exception. This procedure makes the following assumptions:
+; * at most one of the given guards is true in any model,
+; * (vc-assumes vcs[i]) => (vc-assumes (current-vc)) for all i, and 
+; * (vc-asserts vcs[i]) => (vc-asserts (current-vc)) for all i.
+(define (merge-vc! guards vcs)
+  (unless (null? vcs)
+    (define vc*
+      (vc (merge-field vc-assumes (current-vc) guards vcs)
+          (merge-field vc-asserts (current-vc) guards vcs)))
+    (current-vc vc*)
+    (when (false? (vc-assumes vc*))
+      (raise-exn:fail:svm:assume:core "contradiction"))
+    (when (false? (vc-asserts vc*))
+      (raise-exn:fail:svm:assert:core "contradiction"))))
+
+; Sets the current vc to (vc-proc (current-vc) g) where g is (@true? val).
+; If g is #f or the resulting vc's vc-field value is #f,
+; uses raise-exn throws an exn:fail:svm exception. 
+(define-syntax-rule (vc-set! val msg vc-proc vc-field raise-exn)
+  (let* ([guard (@true? val)]
+         [vc* (vc-proc (current-vc) guard)])
+    (current-vc vc*)
+    (when (false? guard)
+      (raise-exn msg))
+    (when (false? (vc-field vc*))
+      (raise-exn "contradiction"))))
+
+; Sets the current vc to (asserting (current-vc) g) where g is (@true? val).
+; If g is #f or the resulting vc's asserts field is #f, throws an
+; exn:fail:svm:assert exception of the given kind.  
+(define-syntax-rule (vc-assert! val msg raise-kind)
+  (vc-set! val msg asserting vc-asserts raise-kind))
+
+; Sets the current vc to (assuming (current-vc) g) where g is (@true? val).
+; If g is #f or the resulting vc's assumes field is #f, throws an
+; exn:fail:svm:assume exception of the given kind. 
+(define-syntax-rule (vc-assume! val msg raise-kind)
+  (vc-set! val msg assuming vc-assumes raise-kind))
+
+; The $assert form has three variants: ($assert val), ($assert val msg),
+; and ($assert val msg kind), where val is the value being asserted, msg
+; is the failure message, and kind is a procedure that returns a subtype of
+; exn:fail:svm:assert. Default values for msg and kind are #f and
+; raise-exn:fail:svm:assert:core, respectively.
+; The first two variants of this form are used for issuing assertions from
+; within the Rosette core. The third variant is used to implement the @assert
+; form that is exposed to user code. An $assert call modifies the current vc to
+; reflect the issued assertion. If the issued assertion or the vc-assert of the
+; current vc reduce to #f, the call throws an exception of the given kind after
+; updating the vc.
+(define-syntax ($assert stx)
+  (syntax-case stx ()
+    [(_ val)          (syntax/loc stx ($assert val #f  raise-exn:fail:svm:assert:core))]
+    [(_ val msg)      (syntax/loc stx ($assert val msg raise-exn:fail:svm:assert:core))]
+    [(_ val msg kind) (syntax/loc stx (vc-assert! val msg kind))]))
+
+; Analogous to the $assert form, except that it modifies the current vc to
+; reflect the issued assumption.
+(define-syntax ($assume stx)
+  (syntax-case stx ()
+    [(_ val)          (syntax/loc stx ($assume val #f   raise-exn:fail:svm:assume:core))]
+    [(_ val msg)      (syntax/loc stx ($assume val msg  raise-exn:fail:svm:assume:core))]
+    [(_ val msg kind) (syntax/loc stx (vc-assume! val msg kind))]))
+
+; The @assert form modifies the current vc to reflect the issued assertion.
+; The form has two variants (@assert val) and (@assert val msg), where val
+; is the value being asserted and msg is the optional error message in case
+; val is #f. This form is exposed to user code.
 (define-syntax (@assert stx)
   (syntax-case stx ()
-    [(_ val) (syntax/loc stx (@assert val #f))]
-    [(_ val msg) 
+    [(_ val)     (syntax/loc stx ($assert val #f  raise-exn:fail:svm:assert:user))]
+    [(_ val msg) (syntax/loc stx ($assert val msg raise-exn:fail:svm:assert:user))]))
+
+; The @assume form modifies the current vc to reflect the issued assumption.
+; The form has two variants (@assume val) and (@assume val msg), where val
+; is the value being assume and msg is the optional error message in case
+; val is #f. This form is exposed to user code.
+(define-syntax (@assume stx)
+  (syntax-case stx ()
+    [(_ val)     (syntax/loc stx ($assume val #f  raise-exn:fail:svm:assume:user))]
+    [(_ val msg) (syntax/loc stx ($assume val msg raise-exn:fail:svm:assume:user))]))
+
+(define (halt-svm ex)
+  (define result (failed ex (current-vc)))
+  ((current-reporter) 'exception result)
+  result)
+
+(define (halt-err ex) ; Treat an exn:fail? error as an assertion failure.
+  (define result
+    (failed (make-exn:fail:svm:assert:err (exn-message ex) (exn-continuation-marks ex))
+          (asserting (current-vc) #f)))
+  ((current-reporter) 'exception result)
+  result)
+
+; The with-vc form has two variants, (with-vc body) and (with-vc vc0 body).
+; The former expands into (with-vc (current-vc) body). The latter sets the current
+; vc to vc0, evaluates the given body, returns the result, and reverts current-vc
+; to the value it held before the call to with-vc.
+;
+; If the evaluation of the body terminates normally, (with-vc vc0 body)
+; outputs (normal v vc*) where v is the value computed by the body, and vc* is 
+; the vc (i.e., assumes and asserts) generated during the evaluation,
+; with vc0 as the initial vc. 
+;
+; If the evaluation of the body terminates abnormally with an exn:fail? exception,
+; (with-vc vc0 body) outputs (failed v vc*) where v is an exn:fail:svm? exception
+; that represents the cause of the abnormal termination, and vc* is the vc
+; generated during the evaluation, with vc0 as the initial vc.
+(define-syntax (with-vc stx)
+  (syntax-case stx ()
+    [(_ body) (syntax/loc stx (with-vc (current-vc) body))]
+    [(_ vc0 body)
      (syntax/loc stx
-       (let ([guard (not-false? val)])
-         (asserts (=> (pc) guard)) 
-         (when (false? guard)
-           (raise-assertion-error msg))))]))
-
-(define (not-false? v)
-  (or (eq? v #t) (! (@false? v))))
-
-(define (raise-assertion-error msg)
-  (if (procedure? msg)
-      (msg)
-      (raise-exn:fail:rosette:assertion (if msg (format "~a" msg) "failed"))))
-
-(define (evaluate-with-asserts closure)
-  (parameterize ([asserts '()])
-    (let* ([val (closure)]
-           [bools (remove-duplicates (asserts))])
-      (values val bools))))
-
-(define-syntax-rule (with-asserts form)
-  (evaluate-with-asserts (thunk form)))
-
-(define-syntax-rule (with-asserts-only form)
-  (let-values ([(out asserts) (with-asserts form)])
-    asserts))
+       (parameterize ([current-vc vc0])
+         (with-handlers ([exn:fail:svm? halt-svm]
+                         [exn:fail?     halt-err])
+           (normal (let () body) (current-vc)))))]))

rosette/base/core/effects.rkt

@@ -1,177 +0,0 @@
-#lang racket
-
-(require 
- (for-syntax racket)
- "../util/ord-dict.rkt" "bool.rkt" "reporter.rkt")
-
-(provide speculate speculate* apply! location=? (rename-out [state-val location-final-value]))
-
-; The env parameter stores an eq? based hash-map which we use to keep
-; track of boxes, vectors and structs that are mutated.  
-(define env (make-parameter #f))
-
-(define-syntax-rule (speculate-core guard body rollback-proc)
-  ; using an eq? rather than equal? hash map to manage the environment bindings
-  ; is critical for mutable objects whose hash code may change upon mutation.  note
-  ; that variables are keyed by the symbol representing their name, so eq? comparisons
-  ; for them are equivalent to equal? comparisons.
-  (parameterize ([env (odict null eq?)])
-    ; roll-back state updates, encapsulate
-    ; updates to set! variables as specified above,
-    ; and return the value of the body together with the
-    ; encapsulation of the state changes according to rollback-proc
-    (with-handlers ([exn:fail? (rollback/suppress guard)])
-      (values body (rollback-proc)))))
-
-; The speculate expression takes the form (speculate body), where body is
-; an expression.  A speculate call produces two values:  the value that the
-; body would produce if executed in the current environment, and a closure 
-; that stores a representation of all state updates that the execution of 
-; body would make.  The closure accepts a two argument function f, and 
-; applies encapsulated state updates so that each updated location is set  
-; to (f v body-v), where body-v is the final value the body would assign to v.  
-;
-; Any exceptions thrown by body are caught, all updates are rolled-back without 
-; encapsulating the final states, and the result of speculate is (values #f #f).
-(define-syntax-rule (speculate guard body)
-  (let ([guard-v guard])
-    (speculate-core guard-v
-                    (parameterize ([pc guard-v]) body)
-                    rollback/encapsulate)))
-
-; The speculate* expression takes the form (speculate* body), where body is
-; an expression.  A speculate* call produces two values:  the value that the
-; body would produce if executed in the current environment, and a list of 
-; locations, each of which encapsulates the pre and post state of a location 
-; mutated during the execution of the body.  The returned locations can be 
-; compared with location=?.  
-;
-; Each encapsulated update acts as a procedure that accepts a two-argument 
-; function f.  The location for the encapsulated updated is then set to 
-; (f v body-v), where body-v is the final value the body would assign to the 
-; location and v is the current value in that location. The procedure 
-; (location-final-value loc) can be used to obtain the final value that the 
-; body would assign to a given location.
-;
-; Any exceptions thrown by body are caught, all updates are rolled-back without 
-; encapsulating the final states, and the result of speculate is (values #f #f).
-(define-syntax-rule (speculate* guard body)
-  (let ([guard-v guard])
-    (speculate-core guard-v
-                    (parameterize ([pc guard-v]) body)
-                    rollback/collect)))
-
-; A function that handles calls to structure mutators.  
-(define apply! 
-  (case-lambda 
-    [(setter getter receiver key val)
-     (record! receiver key getter setter)
-     (setter receiver key val)]
-    [(setter getter receiver val) 
-     (record! receiver setter getter setter)
-     (setter receiver val)]))
-
-; Stores the state of a mutation to the location in a given receiver, 
-; together with getters and setters that can be used to read/write 
-; the mutated location. The val field stores the value that was read 
-; from the location at some point in time (e.g., beginning/end of 
-; speculation).  The attached procedure accepts a two argument function f 
-; and sets the encapsulated location to (f (getter) val).
-(struct state (receiver location val getter setter) 
-  #:transparent
-  #:property prop:procedure 
-  (lambda (self proc) 
-    (let ([receiver (state-receiver self)]
-          [location (state-location self)]
-          [getter (state-getter self)]
-          [setter (state-setter self)])
-      (record! receiver location getter setter) 
-      (cond [(dict? receiver) 
-             (setter receiver location (proc (getter receiver location) (state-val self)))]
-            [else ; struct or box
-             (setter receiver (proc (getter receiver) (state-val self)))]))))
-
-(define (get getter receiver location)
-  (cond [(dict? receiver) (getter receiver location)]
-        [else (getter receiver)]))
-
-(define (state-rollback! s)
-  (let ([receiver (state-receiver s)]
-        [location (state-location s)]
-        [getter (state-getter s)]
-        [setter (state-setter s)])
-    (cond [(dict? receiver) 
-           (setter receiver location (state-val s))]
-          [else ; struct or box
-           (setter receiver (state-val s))])))
-
-; Returns true iff both objects encapsulate updates to the same location.
-(define (location=? s0 s1)
-  (match* (s0 s1)
-    [((state rec0 loc0 _ _ _) (state rec1 loc1 _ _ _))
-     (and (eq? rec0 rec1) (equal? loc0 loc1))]
-    [(_ _) #f]))
-
- 
-; Adds a record of the given variable's or object's current state 
-; to the environment, if the environment is valid and does not 
-; already have a mapping for the record!-ed variable or object.
-(define-syntax-rule (record! obj location getter setter)
-  (when (and (env)
-             (not (env-has-state? obj location))) ; we do this check separately so that the getter/setter  
-    (env-set! obj location getter setter)))       ; lambdas don't get created unless they are needed
-
-; Returns a true value if the current environment (assumed not be #f)
-; has a state record for the given mutation receiver and location of 
-; mutation. For structs, the location is the field-setter function for 
-; the mutated field.  For dictionary objects, the location is the key within the 
-; dictionary to which the dict-set! operation is being applied. For boxes, 
-; the location is the set-box! procedure.
-(define (env-has-state? receiver location)
-  (let ([env (env)])
-    (and (dict-has-key? env receiver)                     ; compound object 
-         (dict-has-key? (dict-ref env receiver) location))))
-
-; Augments env with a mapping from the given receiver to a state record reflecting 
-; the current state at the given location, as obtained by the given getter 
-; procedure. This function assumes that (env-has-state? receiver location) is false.
-(define (env-set! receiver location getter setter)
-  (let ([env (env)]
-        [new-state  (state receiver location (get getter receiver location) getter setter)])
-    (let ([locations (dict-ref! env receiver make-hash)]) ; compound object
-      (dict-set! locations location new-state))))
-
-; Reverts the state of set! variables and struct fields to
-; their initial values, without encapsulating the final state updates.
-; Returns (values #f #f).  The error argument is ignored.
-(define ((rollback/suppress guard) err)
-  ;(printf "\n\nERROR: ~a\n\n" err)
-  ((current-reporter) 'exception guard err)
-  (unless (zero? (dict-count (env)))
-    (for* ([states (in-dict-values (env))]
-           [s (if (list? states) (in-list states) (in-dict-values states))])
-      (state-rollback! s)))    ; roll-back
-  (values #f #f))
-       
-; Reverts the state of set! variables and struct fields to
-; their initial values, and returns an encapsulation of 
-; the final state updates.
-(define (rollback/encapsulate)
-  (if (zero? (dict-count (env)))
-      void
-      (let ([updates (rollback/collect)])
-        (lambda (proc)
-          (for ([s (in-list updates)])
-            (s proc))))))
-
-; Reverts the state of set! variables and struct fields to
-; their initial values, and returns a list that contains a 
-; copy of the final state of each location bound in the current 
-; environment.  
-(define (rollback/collect)
-  (for*/list ([states (in-dict-values (env))]
-              [s (if (list? states) (in-list states) (in-dict-values states))])
-    (let ([final (get (state-getter s) (state-receiver s) (state-location s))])
-      (state-rollback! s)                  ; roll-back
-      (struct-copy state s [val final])))) ; collect final states
-

rosette/base/core/eval.rkt

@@ -0,0 +1,61 @@
+#lang racket
+
+(require
+  (only-in "bool.rkt" with-vc $assume merge-vc!)
+   "exn.rkt" "result.rkt" "store.rkt" "merge.rkt")
+
+(provide eval-assuming eval-guarded!)
+
+; Takes as input a concrete or symbolic boolean and a thunk, 
+; evaluates thunk under the assumption that the guard holds,
+; and returns the result. This result takes one of two forms.
+;
+; If the evaluation of the thunk terminates normally, the result
+; is (normal (normal v st) vc*) where v is the value computed by the
+; thunk, st captures all stores mutations performed during evaluation,
+; and vc* captures the verification condition generated during the
+; evaluation, starting from the current vc.
+;
+; If the thunk terminates abnormally, the result is (failed ex vc*),
+; where ex is an exn:fail:svm? exception that represents the cause
+; of the abnormal termination, and vc* captures the verification
+; condition generated during the evaluation, starting from the current vc.
+;
+; Neither the current store nor the current vc are modified after
+; eval-assuming returns.
+(define (eval-assuming guard thunk)
+  (with-vc
+      (begin 
+        ($assume guard)
+        (with-store (thunk)))))
+
+; Takes as input a list of n guards and n thunks, evaluates each thunk
+; under its guard using eval-assuming, merges the resulting vcs into
+; the current vc, merges the resulting stores (if any) into the current
+; store, and merges the resulting values (if any) before returning them
+; as output. If all of the thunks fail under their guards, eval-guarded
+; raises an exn:fail:svm:merge exception after the specs are merged into
+; the current vc.
+; This procedure makes the following assumptions, based on the Lean
+; formalization:
+; (1) At most one guard evaluates to true under any model.
+; (2) For all models m under which (vc) evaluates to vc-true, there is
+; exactly one guard in guards that evaluates to #t under m.
+; (3) For all models m under which (vc) doesn't evaluate to vc-true,
+; every vc produced by evaluating the given thunks evaluates to
+; the same spec as (vc) under m.
+(define (eval-guarded! guards thunks)
+  (define results (map eval-assuming guards thunks))
+  (merge-vc! guards (map result-state results))
+  (define-values (gs rs)
+    (for/lists (gs rs) ([g guards][r results] #:when (normal? r))
+      (values g (result-value r))))
+  (if (null? rs)
+      (raise-exn:fail:svm:merge)
+      (begin
+        (merge-stores! gs (map result-state rs))
+        (apply merge* (for/list ([g gs][r rs])
+                        (cons g (result-value r)))))))
+
+
+    

rosette/base/core/exn.rkt

@@ -1,21 +1,107 @@
-#lang racket/base
+#lang racket
 
-(provide raise-exn:fail:rosette:infeasible
-         raise-exn:fail:rosette:assertion
-         exn:fail:rosette?
-         exn:fail:rosette:infeasible?
-         exn:fail:rosette:assertion?)
+(require (only-in racket/string string-split)
+         (for-syntax racket/syntax racket/string)
+         racket/provide)
 
-(struct exn:fail:rosette exn:fail ())
-(struct exn:fail:rosette:infeasible exn:fail:rosette ())
-(struct exn:fail:rosette:assertion exn:fail:rosette ())
+(provide (matching-identifiers-out #px"^exn:fail:svm.*\\?$" (all-defined-out))
+         (matching-identifiers-out #px"^make\\-exn:fail:svm.*$" (all-defined-out))
+         (matching-identifiers-out #px"^raise\\-exn:fail:svm.*$" (all-defined-out))
+         exn:fatal? fatal
+         argument-error arguments-error type-error contract-error index-too-large-error)
+
+;; --------------- Exceptions --------------- ;;
+
+; Four kinds of failures can happen during symbolic evaluation:
+; (1) the execution reaches (assert e) where e evaluates to #f, or asserting e reduces vc's asserts to #f; 
+; (2) the execution reaches (assume e) where e evaluates to #f, or assuming e reduces vc's assumes to #f; 
+; (3) the execution reaches e where e raises an exn:fail? exception; and 
+; (4) all paths at a given merge point led to a failure.
+; Within the first two types of failures, we distinguish between
+; assertions and assumptions issued by user code and core (Rosette) code.
+; The third type of failure is treated as an assertion failure for the
+; purposes of verification condition generation. Finally,
+; the fourth type of failure is tracked via exn:fail:svm:merge.
+
+; The top of the exception hierarchy for failures raised
+; during symbolic evaluation.
+(struct exn:fail:svm exn:fail ())
+
+; An assert exception can be one of the following kinds:
+; * :core represents an assertion failure raised in Rosette code,
+; * :user represents an assertion failure raised in user code, and 
+; * :err  indicates that an exn:fail? exception was raised during evaluation. 
+(struct exn:fail:svm:assert exn:fail:svm ())
+(struct exn:fail:svm:assert:core exn:fail:svm:assert ())
+(struct exn:fail:svm:assert:user exn:fail:svm:assert ())
+(struct exn:fail:svm:assert:err exn:fail:svm:assert ())
+
+; An assume exception can be one of the following kinds:
+; * :core represents an assumption failure raised in Rosette code, and 
+; * :user represents an assumption failure raised in user code.
+(struct exn:fail:svm:assume exn:fail:svm ())
+(struct exn:fail:svm:assume:core exn:fail:svm:assume ())
+(struct exn:fail:svm:assume:user exn:fail:svm:assume ())
+
+; An merge exception is raised when all paths at a branching point lead to a failure.
+(struct exn:fail:svm:merge exn:fail:svm ())
+
+(define-syntax (define-make-and-raise stx)
+  (syntax-case stx ()
+    [(_ id)
+     (with-syntax ([make-id (format-id #'id "make-~a" (syntax-e #'id))]
+                   [raise-id (format-id #'id "raise-~a" (syntax-e #'id))]
+                   [prefix (list-ref (string-split (symbol->string (syntax-e #'id)) ":") 3)])
+       #'(begin
+           (define (make-id [msg #f] [cont-marks #f])
+             (id  (format "[~a] ~a" prefix (or msg "failed"))
+                  (or cont-marks (current-continuation-marks))))
+           (define (raise-id [msg #f] [cont-marks #f])
+             (raise (make-id msg cont-marks)))))]
+    [(_ id ...)
+     #'(begin (define-make-and-raise id) ...)]))
+
+; Creates two procedures make-* and raise-* for each exception type that
+; creates and raises an exception of the given type, respectively.
+(define-make-and-raise
+  exn:fail:svm:assert:core
+  exn:fail:svm:assert:user
+  exn:fail:svm:assert:err
+  exn:fail:svm:assume:core
+  exn:fail:svm:assume:user
+  exn:fail:svm:merge)
+  
+;; --------------- Messages --------------- ;;
+
+; Fatal errors indicate bugs in the Rosette implementation.
+; Since Rosette only catches and handles errors of subtype exn:fail?,
+; exn:fatal is a subtype of exn and hence will not be caught as part
+; of symbolic evaluation. 
+(struct exn:fatal exn ())  
+(define (fatal msg) (raise (exn:fatal msg (current-continuation-marks))))
+
+(define (argument-error name expected given)
+  (format "~a: contract violation\n  expected: ~a\n  given: ~a"
+          name expected given))
+
+(define (arguments-error name message . field-value)
+  (define o (open-output-string))
+  (fprintf o "~a: ~a" name message)
+  (let loop ([fvs field-value])
+    (match fvs
+      [(list) (get-output-string o)]
+      [(list f) (fatal (format "arguments-error: missing value after field string ~a" f))]
+      [(list f v rest ...)
+       (fprintf o "\n  ~a: ~a" f v)
+       (loop rest)])))
+
+(define (type-error name expected given)
+  (argument-error name (format "~a" expected) given))  
+  
+(define (contract-error name contract given)
+  (argument-error name (format "~a" (contract-name contract)) given)) 
+  
+(define (index-too-large-error who xs idx)
+  (arguments-error who "index is too large" "index" idx "in" xs))
 
-(define-syntax-rule (raise-exn:fail:rosette:infeasible)
-  (raise (exn:fail:rosette:infeasible
-          "pc: infeasible path condition"
-          (current-continuation-marks))))
 
-(define-syntax-rule (raise-exn:fail:rosette:assertion msg)
-  (raise (exn:fail:rosette:assertion
-          (string-append "assert: " msg)
-          (current-continuation-marks))))

rosette/base/core/forall.rkt

@@ -4,13 +4,12 @@
          syntax/parse/define
          (only-in racket/unsafe/ops [unsafe-car car] [unsafe-cdr cdr])
          (only-in "merge.rkt" merge merge* merge-same)
-         (only-in "bool.rkt" ! || && pc)
+         (only-in "bool.rkt" ! || &&)
          (only-in "union.rkt" union union?)
          (only-in "term.rkt" expression)
          (only-in "polymorphic.rkt" guarded guarded-test guarded-value ite ite*)
          (only-in "equality.rkt" @equal?)
-         (only-in "effects.rkt" speculate* location=? location-final-value)
-         "safe.rkt")
+         "safe.rkt"  "../core/eval.rkt" "../core/store.rkt" "../core/result.rkt")
 
 (provide for/all for*/all guard-apply)
 
@@ -81,9 +80,6 @@
                        (cdr gv))))]
        [_ (list (cons (apply && guards) val))]))))
 
-(define (all-paths-infeasible)
-  (error 'for/all "all paths infeasible"))
-
 ; Applies the given procedure to each of the guarded values,
 ; given as guard/value structures.  The application of the procedure 
 ; to each value is done under the value's guard, and so are all 
@@ -92,64 +88,17 @@
 ; The guard-apply procedure also merges any state updates resulting 
 ; from successful guarded evaluations of proc on the given values.  
 ;
-; All given guards are required to be pairwise mutually exclusive, 
-; and at least one of the guards must always evaluate to true.
+; At most one of the given guards may be true under any model.
 (define (guard-apply proc guarded-values [guard-of car] [value-of cdr])
-  (cond
-    [(andmap (compose1 boolean? guard-of) guarded-values)
-     ;; Either (1) concrete is empty or (2) the value is also concrete.
-     ;; This case doesn't require speculation which is expensive.
-     ;; Simply search for a value in gv pairs whose guard is true
-     ;; and apply proc to it if there's one, error otherwise.
-     (define gv (findf guard-of guarded-values))
+  ; If any of the guarded-values has #t as its guard, it's executed
+  ; directly, since all the guards must be #f under all models.
+  (define gv (findf (lambda (gv) (eq? (guard-of gv) #t)) guarded-values))
   (cond
     [gv   (proc (value-of gv))]
-       [else (assert #f all-paths-infeasible)])]
-    [else
-     (define-values (guards outputs states)
-       (guard-speculate* proc guarded-values guard-of value-of))
-     (when (null? guards) (assert #f all-paths-infeasible))
-     (when (ormap pair? states)
-       (merge-states guards states))
-     (apply merge* (map cons guards outputs))]))
-  
-; Speculatively executes the given procedure on the provided 
-; guarded values and returns three lists---guards, outputs, 
-; and states---of equal length.  For each g/v input value  
-; in guarded-values for which (proc v) terminates without an 
-; error, there is an index i such that the ith element of the 
-; guards list is g, the ith element of the outputs list is 
-; (proc v), and the ith element of the states list is the list 
-; of all states updates that were performed when executing (proc v).
-; Note that all state update objects for the ith execution are  
-; are unique according to location=?, but two state updates in 
-; different executions may be location=?.  (That is, proc would 
-; update the same location if it were called with two different 
-; values.)
-(define (guard-speculate* proc guarded-values [guard-of car] [value-of cdr])
-  (for/fold ([guards '()] [outputs '()] [states '()]) ([gv guarded-values])
-    (define guard (guard-of gv))
-    (define val (value-of gv))
-    (define-values (output state) (speculate* guard (proc val)))
-    (cond [state (values (cons guard guards) (cons output outputs) (cons state states))]
-          [else  (assert (! guard) all-paths-infeasible)
-                 (values guards outputs states)])))
+    [else (eval-guarded! (map guard-of guarded-values)
+                         (map (lambda (gv) (thunk (proc (value-of gv)))) guarded-values))]))
+  
+
   
 
-; Given a list of n guards and their corresponding lists of 
-; state-update objects, performs an n-way merge of all updates 
-; to memory locations that are encapsulated in those states.
-(define (merge-states guards states)
-  (define locations (remove-duplicates (apply append states) location=?))
-  (define guarded-states (append-map (lambda (g sts) (map (curry cons g) sts)) guards states))
-  (define max-guards-per-location (length guards))
-  (define (merge-procedure gss)
-    (if (= (length gss) max-guards-per-location)
-        (lambda (pre post) (apply merge* gss))
-        (lambda (pre post) (apply merge* (cons (! (apply || (map car gss))) pre) gss))))
-  (for ([loc locations]) 
-    (loc (merge-procedure 
-          (for/list ([gs guarded-states] 
-                     #:when (location=? loc (cdr gs))) 
-            (cons (car gs) (location-final-value (cdr gs))))))))
            

rosette/base/core/merge.rkt

@@ -1,7 +1,6 @@
 #lang racket
 
-(require (only-in rnrs/base-6 assert)
-         (only-in racket/unsafe/ops [unsafe-car car] [unsafe-cdr cdr])
+(require (only-in racket/unsafe/ops [unsafe-car car] [unsafe-cdr cdr])
          "term.rkt" "union.rkt" "bool.rkt" "reporter.rkt")
 
 (provide merge merge* unsafe-merge* merge-same)
@@ -35,70 +34,56 @@
   (let ([simp (simplify ps)])
     ((current-reporter) 'merge (length simp))
     (match (compress force? simp)
-      [(list (cons g v)) (assert (not (false? g))) v]
+      [(list (cons g v)) v]
       [(list _ (... ...) (cons #t v) _ (... ...)) v]
       [vs (apply union vs)])))
 
-(define (guard-&& a b)
-  (match b  
-    [(expression (== @&&) c ...) (apply && a c)]
-    [_ (&& a b)])) 
-
-(define (guard g vs)
-  (filter-map (lambda (v) 
-                (let ([gv (guard-&& g (car v))])
-                  (and gv (cons gv (cdr v)))))
-              vs))
+(define (guard g gvs)
+  (for*/list ([gv gvs]
+              [gg (in-value (&& g (car gv)))]
+              #:when gg)
+    (cons gg (cdr gv))))
 
 (define (simplify ps)
-  (let loop ([ps ps] [out '()])
   (match ps
-      [(list) out]
-      [(list (and (cons #t v) p) _ ...) 
+    [(list _ ... (and (cons #t _) p) _ ...)
      (list p)]
-      [(list (cons #f _) rest ...) 
-       (loop rest out)]
-      [(list (cons g (union (and (not (? null?)) vs))) rest ...) 
-       (loop rest (append (guard g vs) out))]
-      [(list p rest ...) 
-       (loop rest (cons p out))])))
+    [_ (for/fold ([out '()]) ([p ps])
+         (match p
+           [(cons #f _) out]
+           [(cons g (union (and (not (? null?)) gvs)))
+            (append (guard g gvs) out)] 
+           [_ (cons p out)]))]))
 
-(define (group ps)
-  (let ([types (remove-duplicates (for/list ([p ps]) (type-of (cdr p))))])
-    (for*/list ([t types] [p ps] #:when (equal? t (type-of (cdr p)))) p)))
+(define (type-of-value gv) (type-of (cdr gv)))
 
 (define (compress force? ps)
   (match ps
     [(list _) ps] 
-    [(list (cons g (app type-of t)) (cons h (app type-of t))) 
+    [(list (cons _ (app type-of t)) (cons _ (app type-of t))) 
      (type-compress t force? (merge-same ps))]
     [(list _ _) ps]
-    [_ (let loop ([ps (group ps)] [type #f] [acc '()])
-         ;(printf "compress ~a ~a ~a\n" ps type acc)
-         (match ps
-           [(list) 
-            (append-map (lambda (group) 
-                          (type-compress (type-of (cdar group)) 
+    [_ (append-map
+        (lambda (group)
+          (type-compress
+           (type-of (cdar group)) 
            force? 
            (merge-same group)))
-                        acc)]
-           [(list (and (cons _ (app type-of (== type))) p) rest ...)
-            (loop rest type (cons (cons p (car acc)) (cdr acc)))]
-           [(list p rest ...)
-            (loop rest (type-of (cdr p)) (cons (list p) acc))]))]))
+        (group-by type-of-value ps))]))
 
 (define (merge-same ps)
-  ;(printf "merge ~a\n" ps)
   (match ps
     [(or (list) (list _)) ps]
-    [(list (cons g v) (cons h u)) (if (eq? v u) (list (cons (|| g h) v)) ps)]
-    [_ (let loop ([ps ps] [out '()])
-         (if (null? ps)
-             out
-             (match-let*-values 
-              ([((cons g v)) (car ps)]
-               [((list (cons h _) ...) rest) (partition (compose (curry eq? v) cdr) (cdr ps))]
-               [(g) (apply || g h)])
-              (if (equal? g #t)
+    [(list (cons g v) (cons h u))
+     (if (eq? v u) (list (cons (|| g h) v)) ps)]
+    [_ (let loop ([ps (group-by cdr ps eq?)] [out '()])
+         (match ps
+           [(list) out]
+           [(list (list gv) rest ...)
+            (loop rest (cons gv out))]
+           [(list group rest ...)
+            (let ([g (apply || (map car group))]
+                  [v (cdar group)])
+              (if (eq? g #t)
                   (list (cons g v))
-                  (loop rest (cons (cons g v) out))))))]))
+                  (loop rest (cons (cons g v) out))))]))]))

rosette/base/core/numerics.rkt

@@ -7,10 +7,7 @@
 (provide @number? @positive? @negative? @zero? @even? @odd?
          @add1 @sub1 @sgn @truncate @floor @ceiling @min @max
          @exact->inexact @inexact->exact @expt
-         extreme
-         ;@sqrt @bitwise-not @bitwise-and @bitwise-ior @bitwise-xor
-         ;@<< @>> @>>> @bitwise-bit-set? @bitwise-bit-field
-         )
+         extreme)
 
 (define (@number? v)   (or (number? v) (@real? v)))
 (define (@positive? x) (@> x 0))

rosette/base/core/polymorphic.rkt

@@ -152,7 +152,7 @@
   (match* ((car p) (cdr p))
     [(a (expression (== ite) a x _)) (cons a x)]
     [(a (expression (== ite) (expression (== @!) a) _ x)) (cons a x)]
-    [((expression (== @!) a) (expression (== ite) a _ x)) (cons a x)]
+    [((and (expression (== @!) a) !a) (expression (== ite) a _ x)) (cons !a x)]
     [(_ _) p]))
 
 

rosette/base/core/procedure.rkt

@@ -3,7 +3,7 @@
 (require 
   racket/provide 
   (for-syntax racket/syntax (only-in "lift.rkt" with@)) 
-  (only-in "type.rkt" define-lifted-type typed? get-type subtype? type-applicable? @any/c)
+  (only-in "type.rkt" define-lifted-type type-cast typed? get-type subtype? type-applicable? @any/c)
   (only-in "bool.rkt" || @false?)
   (only-in "union.rkt" union union? in-union-guards union-filter union-guards)
   (only-in "safe.rkt" assert argument-error)
@@ -75,8 +75,8 @@
     [(union gvs)    (guard-apply (curryr procedure-rename name) gvs)]
     [(? procedure?) (procedure-rename proc name)]))
 
-(define (@negate f)
-  (unless (@procedure? f) (raise-argument-error 'negate "procedure?" f))
+(define (@negate p)
+  (define f (type-cast @procedure? p 'negate))
   (let-values ([(arity) (procedure-arity f)] [(_ kwds) (procedure-keywords f)])
     (case (and (null? kwds) arity) ; optimize some simple cases
       [(0) (lambda () (@false? (f)))]

rosette/base/core/real.rkt

@@ -295,7 +295,7 @@
 (define T*->integer? (const @integer?))
 
 (define (undefined-for-zero-error name)
-  (thunk (raise-arguments-error name "undefined for 0")))
+  (arguments-error name "undefined for 0"))
   
 (define-syntax-rule (define-lifted-int-operator @op $op op)
   (define-operator @op

rosette/base/core/reflect.rkt

@@ -1,16 +1,17 @@
 #lang racket
 
 (require (only-in "forall.rkt" for/all for*/all) 
-         "term.rkt" "union.rkt")
+         "term.rkt" "union.rkt" "result.rkt")
 
 (provide type? solvable? @any/c type-of type-cast for/all for*/all
          term? constant? expression? 
          term expression constant
-         term-type term=? 
-         term->datum clear-terms! term-cache
+         term-type term=? term->datum
+         terms terms-count terms-ref with-terms clear-terms! gc-terms!
          union? union union-contents union-guards union-values
          union-filter in-union in-union* in-union-guards in-union-values
-         symbolics)
+         (struct-out normal) (struct-out failed) result? result-value result-state
+         symbolics concrete? symbolic?)
 
 (define (term=? s0 s1)
   (and (term? s0) (term? s1) (equal? s0 s1)))
@@ -18,27 +19,57 @@
 (define (symbolics vs)
   (match vs
     [(list (? constant?) ...) (remove-duplicates vs)]
-    [_ (let ([cache (mutable-set)]
+    [(? constant?) (list vs)]
+    [_ (let ([terms (mutable-set)]
+             [objs  (mutable-set)]
              [result '()])
-         (let loop ([vs vs])
-           (unless (set-member? cache vs)
-             (set-add! cache vs)
-             (match vs
+         (let loop ([datum vs])
+           (if (term? datum)
+               (let ([id (term-id datum)])
+                 (unless (set-member? terms id)
+                   (set-add! terms id)
+                   (match datum
+                     [(expression _ x ...) (for-each loop x)]
+                     [(? constant?) (set! result (cons datum result))]))) 
+               (unless (set-member? objs datum)
+                 (set-add! objs datum)
+                 (match datum
                    [(union (list (cons guard value) ...))
                     (for-each loop guard) (for-each loop value)]
-               [(expression _ x ...) (for-each loop x)]
-               [(? constant? v) (set! result (cons v result))]
                    [(box v) (loop v)]
-               [(? list?) (for-each loop vs)]
+                   [(? list?) (for-each loop datum)]
                    [(cons x y) (loop x) (loop y)]
                    [(vector v ...) (for-each loop v)]
                    [(and (? typed?) (app get-type t))
-                (match (type-deconstruct t vs)
-                  [(list (== vs)) (void)]
+                    (match (type-deconstruct t datum)
+                      [(list (== datum)) (void)]
                       [components (for-each loop components)])]
-               [_ (void)])))
+                   [_ (void)]))))
          (reverse result))]))
 
+(define (concrete? val)
+  (define objs (mutable-set))
+  (let all-concrete? ([val val])
+    (and (not (term? val))
+         (not (union? val))
+         (or
+          (set-member? objs val)
+          (begin
+            (set-add! objs val)
+            (match val
+              [(box v) (all-concrete? v)]
+              [(? list?) (for/and ([v val]) (all-concrete? v))]
+              [(cons x y) (and (all-concrete? x) (all-concrete? y))]
+              [(? vector?) (for/and ([v val]) (all-concrete? v))]
+              [(and (? typed?) (app get-type t))
+               (match (type-deconstruct t val)
+                 [(list (== val)) #t]
+                 [components (for/and ([v components]) (all-concrete? v))])]
+              [_ #t]))))))
+
+(define (symbolic? val) (not (concrete? val)))
+    
+
 (define (term->datum val)
   (let convert ([val val] [cache (make-hash)])
     (if (hash-has-key? cache val) 

rosette/base/core/result.rkt

@@ -0,0 +1,17 @@
+#lang racket
+
+(provide (struct-out normal) (struct-out failed)
+         result? result-value result-state)
+
+; Represents the result of symbolic evaluation,
+; which includes an output value and a representation
+; of some aspect of the symbolic state.
+(struct result (value state) #:transparent)
+
+; Represents the result of a normally terminated evaluation.
+(struct normal result () #:transparent)
+
+; Represents the result of an evaluation that resulted in
+; an exn:fail? exception being raised. In this case,
+; the result-value field stores the exception that was raised.
+(struct failed result () #:transparent)

rosette/base/core/safe.rkt

@@ -1,57 +1,38 @@
 #lang racket
 
-(require (only-in "type.rkt" type-cast)
-         "bool.rkt"
-         racket/performance-hint)
+(require "bool.rkt" "exn.rkt")
 
 (provide argument-error arguments-error type-error contract-error index-too-large-error
          assert assert-some assert-|| assert-bound assert-arity-includes)
 
-(begin-encourage-inline
-  
-  (define (arguments-error name message . field-value)
-    (thunk (apply raise-arguments-error name message field-value)))
-  
-  (define (argument-error name expected given)
-    (thunk (raise-argument-error name expected given)))
-  
-  (define (type-error name expected given)
-    (argument-error name (format "~a" expected) given))  
-  
-  (define (contract-error name contract given)
-    (argument-error name (format "~a" (contract-name contract)) given)) 
-  
-  (define (index-too-large-error who xs idx)
-    (arguments-error who "index is too large" "index" idx "in" xs))
-  )
   
 (define-syntax (assert stx)
   (syntax-case stx ()
-    [(_ expr err-thunk)        (syntax/loc stx (@assert expr err-thunk))]
-    [(_ expr)                  (syntax/loc stx (@assert expr #f))]))
+    [(_ expr)      (syntax/loc stx ($assert expr #f))]
+    [(_ expr msg)  (syntax/loc stx ($assert expr msg))]))
 
 (define-syntax assert-some 
   (syntax-rules ()
-    [(_ expr #:unless size err-thunk) 
+    [(_ expr #:unless size msg) 
      (let* ([val expr])
        (unless (= size (length val))
-         (assert (apply || (map car val)) err-thunk))
+         (assert (apply || (map car val)) msg))
        val)]
     [(_ expr #:unless size)
      (assert-some expr #:unless size #f)]
-    [(_ expr err-thunk)
+    [(_ expr msg)
      (let* ([val expr])
-       (assert (apply || (map car val)) err-thunk)
+       (assert (apply || (map car val)) msg)
        val)]
     [(_ expr)
      (assert-some expr #f)]))
 
 (define-syntax assert-|| 
   (syntax-rules ()
-    [(_ expr #:unless size err-thunk) 
+    [(_ expr #:unless size msg) 
      (let ([val expr])
        (unless (= size (length val))
-         (assert (apply || val) err-thunk)))]
+         (assert (apply || val) msg)))]
     [(_ expr #:unless size) (assert-|| expr #:unless size #f)]))
 
 

rosette/base/core/store.rkt

@@ -0,0 +1,181 @@
+#lang racket
+
+(require "result.rkt" "merge.rkt")
+
+(provide with-store store! merge-stores!
+         location? location-base location-offset
+         location-ref location-set!)
+
+; The current-store parameter contains a store that 
+; maps (abstract) memory locations to values.  Each mapped
+; location identifies a storage cell that has been the mutated
+; via a store! call in the dynamic extent of a call to
+; with-store. The store maps each such location to the value
+; that was stored at that location before the current call 
+; to with-store.
+(define current-store (make-parameter #f))
+
+; A store maps abstract memory locations to their initial values.
+; An abstract memory location identifies a storage cell that holds
+; a single value; locations consist of a base object (e.g., a vector)
+; and an offset value (e.g., the index 0) that identifies a
+; storage cell within that object.
+;
+; A store uses a refs set, as returned by make-refs, to keep track
+; of the locations that have been mutated via store! calls.
+; The initial value of each mutated location is held in the store's
+; vals list. This list maps locations to the values they held prior
+; to the current call to with-store.
+(struct store (refs [vals #:mutable]) #:transparent)
+
+; Returns an empty store.
+(define (make-store) (store (make-refs) (list)))
+
+; Returns an empty set of base/offset pairs.
+(define (make-refs) (make-hasheq))
+
+; Adds the given base/offset pair to rs if not
+; already present. Returns #t if rs changed as
+; a result of this operation; otherwise returns #f.
+(define (refs-add! rs base offset)
+  (define bits (hash-ref rs base 0))
+  (and (not (bitwise-bit-set? bits offset))
+       (hash-set! rs base (bitwise-ior bits (arithmetic-shift 1 offset)))
+       #t))
+
+; Extends the store s with a mapping from the location
+; (loc base offset getter setter) to its current value,
+; unless s already contains a mapping for this location.
+(define (store-add! s base offset getter setter)
+  (when (refs-add! (store-refs s) base offset)
+    (let ([l (location base offset getter setter)]
+          [vals (store-vals s)])
+        (set-store-vals! s (cons (cons l (location-ref l)) vals)))))
+
+; Performs the mutation to the storage
+; cell at the location (loc base offset getter setter),
+; and if this cell has not been mutated before, its
+; initial value is added to current-store.
+; The getter and setter procedures should read / write
+; the cell's value when applied to its base and offset.
+(define (store! base offset val getter setter)
+  (let ([s (current-store)])
+    (when s
+      (store-add! s base offset getter setter)))
+  ;(printf "store! ~a ~a ~a ~a ~a, ~a\n" base offset val getter setter (current-store))
+  (setter base offset val))
+
+; Returns true if the store s is empty.
+(define (store-empty? s)
+  (zero? (length (store-vals s))))
+
+; Represents the location of a single mutable storage cell.
+; A cell location consists of a base object (e.g., a vector)
+; and an offset value (e.g., 0) that identifies a
+; storage cell within that object. Locations 
+; also include getter and setter procedures that can be
+; used to read from and write to the referenced cell.
+; Two locations are equal? iff their base and offset
+; are both eq? to one another.
+(struct location (base offset accessor mutator)
+  #:transparent
+  #:methods gen:equal+hash
+  [(define (equal-proc l1 l2 rec-equal?)
+     (and (eq? (location-base l1) (location-base l2))
+       (eq? (location-offset l1) (location-offset l2))))
+   (define (hash-proc l rec-equal-hash)
+     (equal-hash-code (cons (eq-hash-code (location-base l)) (eq-hash-code (location-offset l)))))
+   (define (hash2-proc l rec-equal-hash2)
+     (equal-secondary-hash-code (cons (eq-hash-code (location-base l)) (eq-hash-code (location-offset l)))))])
+
+; Returns the current value stored at the location l.
+(define (location-ref l)
+  ((location-accessor l) (location-base l) (location-offset l)))
+
+; Stores the value v at the location l.
+(define (location-set! l v)
+  (store! (location-base l) (location-offset l) v (location-accessor l) (location-mutator l)))
+
+; Rollbacks the contents of all mutated storage cells to their initial 
+; values, as given in (current-store), and raises the exception e.
+; The current-store is assumed to contain the values that  
+; mutated cells held before the current call to with-store.
+; This procedure can be called only in the dynamic extent of a
+; with-store call.
+(define (rollback-exn! e)
+  ;(printf "exn: ~a\n" e)
+  (for ([lv (store-vals (current-store))])
+    (match-define (cons (location base offset _ setter) init) lv)
+    (setter base offset init))
+  (raise e))
+
+; Rollbacks the contents of all mutated storage cells to their initial 
+; values, as given in (current-store), and returns a list of pairs
+; that maps a reference to each mutated cell to its current value.
+; The current-store is assumed to contain the values that  
+; mutated cells held before the current call to with-store.
+; This procedure can be called only in the dynamic extent of a
+; with-store call.
+(define (rollback-capture!)
+  ;(printf "capture: ~a\n"  (store-vals (current-store)))
+  (for/list ([lv (store-vals (current-store))])
+    (match-define (cons (location base offset getter setter) init) lv)
+    (define fin (getter base offset))
+    (setter base offset init)
+    (cons (car lv) fin)))
+
+; The with-store form takes as input an expression, evaluates it,
+; and reverts each mutated memory location to its pre-state 
+; (i.e., the value it held before the call to with-store).
+; 
+; If the evaluation of the body terminates normally, (with-store body)
+; outputs a result (normal v s) where v is the value computed by the body,
+; and s is an association list that maps each mutated location? to its
+; post-state (i.e., the value it held after the evaluation of the body).
+; In essence, evaluating the body in the current environment has the
+; same effect on memory as evaluating (with-store body) and then setting
+; the returned memory locations to their post-state value.
+; 
+; If the evaluation of the body terminates abnormally with an exn:fail?
+; exception, with-store reverts all mutated locations to their pre-state
+; and re-raises the same exception. 
+(define-syntax-rule (with-store body)
+  (parameterize ([current-store (make-store)])
+    (with-handlers ([exn:fail? rollback-exn!])
+      (let ([out body])  
+        (normal out (rollback-capture!))))))
+
+; Takes as input a list of n guards and a list of n stores, where
+; each store is a list of location/value pairs. For each location l
+; occurring in the stores, merge-store mutates l to contain the value
+; m = (merge* ... (cons gi vi) ...), where gi = guards[i] and
+; vi = stores[i][l] if stores[i] has a binding for l; otherwise, 
+; vi = (location-ref l). The procedure assumes that no store contains a
+; duplicate binding for any location.
+; 
+; This store merging procedure is correct under the assumption that 
+; (1) the guards are disjoint under all models (i.e., at most one 
+; is ever true), and (2) the verification conditions force at least 
+; one guard to be true under all models that satisfy both the
+; asserts and the assumes. 
+(define (merge-stores! guards stores)
+  (match stores
+    [(list (list) ...)   (void)]                    ; Nothing to merge.
+    [(list s) (for ([lv s])                         ; If given only one store, just apply its effects 
+                (location-set! (car lv) (cdr lv)))] ; since its guard must be true under the current spec.
+    [_ (define hash-stores (map make-hash stores))
+       (for ([lv (remove-duplicates (apply append stores) equal? #:key car)])
+         (define loc (car lv))
+         (define val (location-ref loc))
+         (location-set! loc
+            (apply merge*
+                   (for/list ([g guards] [hs hash-stores])
+                     (cons g (if (hash-has-key? hs loc)
+                                 (hash-ref hs loc)
+                                 val))))))]))  
+  
+
+
+
+
+

rosette/base/core/term.rkt

@@ -1,32 +1,38 @@
 #lang racket
 
-(require racket/syntax (for-syntax racket racket/syntax) racket/generic
+(require racket/syntax (for-syntax racket racket/syntax syntax/parse)
+         racket/generic syntax/parse 
          "type.rkt" "reporter.rkt")
 
 (provide
- term-cache clear-terms!
+ terms terms-count terms-ref with-terms clear-terms! gc-terms!
  term? constant? expression? 
- (rename-out [a-term term] [an-expression expression] [a-constant constant]) 
+ (rename-out [a-term term] [an-expression expression] [a-constant constant] [term-ord term-id]) 
  term-type term<? sublist? @app
  define-operator operator? operator-unsafe
  (all-from-out "type.rkt"))
 
 #|-----------------------------------------------------------------------------------|#
-; Term cache stores terms for the purposes of partial cannonicalization.
+; The current-terms cache stores terms for the purposes of partial cannonicalization.
 ; That is, it ensures that no syntactically identical terms are created.
-; It also assigns unique IDs (creation timestamps) to terms.  These IDs
-; are never reused, and they are used to impose an ordering on the children
+; The current-index parameter is used to assign unique IDs (creation timestamps) to terms.
+; These IDs are never reused, and they are used to impose an ordering on the children
 ; of expressions with commutative operators.
 #|-----------------------------------------------------------------------------------|#
-(define term-cache (make-parameter (make-hash)))
-(define term-count (make-parameter 0))
 
-; Clears the entire term-cache if invoked with #f (default), or 
+;; Initialize with #f so that the hash table cooperates with garbage collector.
+;; See #247
+(define current-terms (make-parameter #f))
+(current-terms (make-hash))
+
+(define current-index (make-parameter 0))
+
+; Clears the entire term cache if invoked with #f (default), or 
 ; it clears all terms reachable from the given set of leaf terms.
 (define (clear-terms! [terms #f])
   (if (false? terms)
-      (hash-clear! (term-cache))
-      (let ([cache (term-cache)]
+      (hash-clear! (current-terms))
+      (let ([cache (current-terms)]
             [evicted (list->mutable-set terms)])
         (for ([t terms])
           (hash-remove! cache (term-val t)))
@@ -40,12 +46,70 @@
               (set-add! evicted t))
             (loop))))))
 
+; Sets the current term cache to a garbage-collected (weak) hash.
+; The setting preserves all reachable terms from (current-terms).
+(define (gc-terms!)
+  (unless (hash-weak? (current-terms)) ; Already a weak hash.
+    (define cache
+      (impersonate-hash
+       (make-weak-hash)
+       (lambda (h k)
+         (values k (lambda (h k e) (ephemeron-value e #f))))
+       (lambda (h k v)
+         (values k (make-ephemeron k v)))
+       (lambda (h k) k)
+       (lambda (h k) k)
+       hash-clear!))
+    (for ([(k v) (current-terms)])
+      (hash-set! cache k v))
+    (current-terms cache)))
+
+; Returns the term from current-terms that has the given contents. If
+; no such term exists, failure-result is returned, unless it is a procedure.
+; If failure-result is a procedure, it is called and its result is returned instead.
+(define (terms-ref contents [failure-result (lambda () (error 'terms-ref "no term for ~a" contents))])
+  (hash-ref (current-terms) contents failure-result))
+
+; Returns a list of all terms in the current-term scache, in an unspecified order.
+(define (terms)
+  (hash-values (current-terms)))
+
+; Returns the size of the current-terms cache.
+(define (terms-count)
+  (hash-count (current-terms)))
+
+; Evaluates expr with (terms) set to terms-expr, returns the result, and
+; restores (terms) to its old value. If terms-expr is not given, it defaults to
+; (terms), so (with-terms expr) is equivalent to (with-terms (terms) expr).
+(define-syntax (with-terms stx)
+  ;; Parameterize with #f so that the hash table cooperates with garbage collector.
+  ;; See #247
+  (syntax-parse stx
+    [(_ expr)
+     #'(let ([orig-terms (current-terms)])
+         (parameterize ([current-terms #f])
+           (current-terms (hash-copy orig-terms))
+           expr))]
+    [(_ terms-expr expr)
+     #'(let ([orig-terms (current-terms)])
+         (parameterize ([current-terms #f])
+           (current-terms (hash-copy-clear orig-terms))
+           (let ([ts terms-expr]
+                 [cache (current-terms)])
+             (for ([t ts])
+               (hash-set! cache (term-val t) t))
+             expr)))]))
+           
+         
+    
+
 #|-----------------------------------------------------------------------------------|#
 ; The term structure defines a symbolic value, which can be a variable or an expression.
 ; The val field of a constant is its unique identifier, and it can be anything.  The val
 ; field of an expression is a list, in which the first argument is always a function.
 ; That function can be interpreted (that is, an operator), or uninterpreted (that is,
-; its interpretation is determined by the solver).
+; its interpretation is determined by the solver). Terms are totally ordered and a 
+; subterm is guaranteed to be term<? than its parent.
 #|-----------------------------------------------------------------------------------|#
 (struct term 
   (val                 ; (or/c any/c (cons/c function? (non-empty-listof any/c)))
@@ -68,14 +132,21 @@
 (define (term<? s1 s2) (< (term-ord s1) (term-ord s2)))
 
 (define-syntax-rule (make-term term-constructor args type rest ...) 
-  (let ([val args])
-    (or (hash-ref (term-cache) val #f)
-        (let* ([ord (term-count)]
-               [out (term-constructor val type ord rest ...)])
-          (term-count (add1 ord))
+  (let ([val args]
+        [ty type])
+    (define cached (hash-ref (current-terms) val #f))
+    (cond
+      [cached
+       (unless (equal? (term-type cached) ty)
+         (error 'define-symbolic "type should remain unchanged"))
+       cached]
+      [else
+       (define ord (current-index))
+       (define out (term-constructor val ty ord rest ...))
+       (current-index (add1 ord))
        ((current-reporter) 'new-term out)
-          (hash-set! (term-cache) val out)
-          out))))
+       (hash-set! (current-terms) val out)
+       out])))
            
 (define (make-const id t) 
   (unless (and (type? t) (solvable? t))

rosette/base/core/type.rkt

@@ -43,8 +43,8 @@
   [type-cast type val [caller]]       ; (-> type? any/c symbol? any/c)
   [type-name type]                    ; (-> type? symbol?)
   [type-applicable? type]             ; (-> type? boolean?)
-  [type-eq? type u v]                 ; (-> type? (-> any/c any/c @boolean?)))
-  [type-equal? type u v]              ; (-> type? (-> any/c any/c @boolean?)))
+  [type-eq? type u v]                 ; (-> type? any/c any/c @boolean?)
+  [type-equal? type u v]              ; (-> type? any/c any/c @boolean?)
   [type-compress type force? ps]      ; (-> type? (listof (cons @boolean? any/c)) (listof (cons @boolean? any/c)))
   [type-construct type vals]          ; (-> type? (listof any/c) any/c)
   [type-deconstruct type val])        ; (-> type? any/c (listof any/c))

rosette/base/core/union.rkt

@@ -20,19 +20,18 @@
   [(define (get-type self) (union-type self))]
   #:methods gen:custom-write
   [(define (write-proc self port mode) 
-     (fprintf port "{")
+     (fprintf port "(union")
      (case mode
        [(#t #f) 
-        (fprintf port "~a:~a" (equal-hash-code self) (length (union-contents self)))]
+        (fprintf port " #:size ~a #:hash ~a" (length (union-contents self)) (equal-hash-code self))]
        [else
         (let ([vs (union-contents self)])
           (unless (null? vs)
             (parameterize ([error-print-width (max 4 (quotient (error-print-width) (* 2 (length vs))))])
-              (fprintf-entry port (car vs) mode)
-              (for ([v (cdr vs)])
+              (for ([v vs])
                 (fprintf port " ")
                 (fprintf-entry port v mode)))))])
-     (fprintf port "}"))])
+     (fprintf port ")"))])
 
 (define (fprintf-entry port p mode)
   (fprintf port "[")

rosette/base/form/control.rkt

@@ -1,27 +1,12 @@
 #lang racket
 
-(require "../core/effects.rkt"  
+(require "../core/eval.rkt" "../core/store.rkt" "../core/result.rkt"
          "../core/term.rkt" "../core/equality.rkt" 
          "../core/merge.rkt" "../core/bool.rkt")
 
 (provide @if @and @or @not @nand @nor @xor @implies
          @unless @when @cond @case else)
   
-; Symbolic conditions are handled by speculatively executing both branches,
-; and then merging their results and updates to state (if any). When a branch is 
-; executed speculatively, its state mutations are captured and then undone. 
-; The result of the capture is a closure that can be used with a merging 
-; procedure to selectively re-apply the updates.  If an error is thrown 
-; during speculation, all updates are undone, but they are not captured 
-; (since the branch is infeasible).  After both branches have been speculatively 
-; executed, their results and updates to state are merged using the merge function.
-;
-; Speculative execution of either branch is guarded by the path condition, stored 
-; in the pc parameter.  Parameterizing pc with a new value coinjoins that 
-; value with the current path condition. If the result of the conjunction is false, 
-; indicating that the branch is infeasible, an error is thrown, and the branch is 
-; not executed.  The error is captured by the speculate form and later handled by 
-; the merge function.
 (define-syntax (@if stx)
   (syntax-case stx ()
     [(_ test-expr then-expr else-expr)
@@ -31,28 +16,10 @@
                          (thunk else-expr)))]))
 
 (define (branch-and-merge test-expr then-branch else-branch)
-  (define test (! (@false? test-expr)))
+  (define test (@true? test-expr))
   (cond [(eq? test #t) (then-branch)]
         [(eq? test #f) (else-branch)]
-        [else 
-         (let-values ([(then-val then-state) (speculate test (then-branch))]
-                      [(else-val else-state) (speculate (! test) (else-branch))])
-           (cond [(and then-state else-state) ; both branches feasible
-                  (then-state (lambda (pre post-then) (merge test post-then pre)))
-                  (else-state (lambda (post-then post-else) (merge test post-then post-else)))
-                  (merge test then-val else-val)]
-                 [then-state                  ; only then branch feasible
-                  (@assert test "both branches infeasible")
-                  (then-state select-post)
-                  then-val]
-                 [else-state                  ; only else branch feasible
-                  (@assert (! test) "both branches infeasible")
-                  (else-state select-post)
-                  else-val]
-                 [else                        ; neither branch feasible
-                  (@assert #f "both branches infeasible")]))]))
-
-(define (select-post pre post) post) 
+        [else (eval-guarded! (list test (! test)) (list then-branch else-branch))]))
 
 (define-syntax (@and stx)
   (syntax-case stx ()

rosette/base/form/define.rkt

@@ -1,85 +1,48 @@
 #lang racket
  
-(require (for-syntax racket)
-         "../util/array.rkt" "../core/term.rkt" "state.rkt")
+(require syntax/parse (for-syntax syntax/parse racket)
+         "../core/term.rkt")
 
 (provide define-symbolic define-symbolic*)
 
-#|--------------define forms--------------|#
+(define-for-syntax (module-or-top? . args)
+  (case (syntax-local-context)
+    [(module top-level) #t]
+    [else #f]))
+
+(define-for-syntax (static? k)
+  (with-handlers ([exn:fail? module-or-top?])
+    (natural? (eval k)))) 
 
 (define-syntax (define-symbolic stx)
-  (syntax-case stx ()
-    [(_ var type)
-     (identifier? #'var)
-     (syntax/loc stx (define var (constant #'var type)))]
-    [(_ var type [ k ... ])
-     (and (identifier? #'var) (implies (identifier? #'type) (identifier-binding #'type)))
-     (define-array stx #'var #'type #'(k ...))]
-    [(_ v ... type)
-     (andmap identifier? (syntax->list #'(v ...)))
-     (syntax/loc stx (define-values (v ...) (values (constant #'v type) ...)))]))
+  (syntax-parse stx
+    [(_ var:id type)
+     #'(define var (constant #'var type))]
+    [(_ var:id type #:length k)
+     #:declare k (expr/c #'natural? #:name "length argument")
+     #:fail-unless (static? #'k) "expected a natural? for #:length"
+     #'(define var
+         (for/list ([i k.c])
+           (constant (list #'var i) type)))]
+    [(_ var:id ...+ type)
+     #'(begin (define-symbolic var type) ...)]))
+
+(define current-index (make-parameter 0))
+
+(define (index!)
+  (define idx (current-index))
+  (current-index (add1 idx))
+  idx)
 
 (define-syntax (define-symbolic* stx)
-  (syntax-case stx ()
-    [(_ [var oracle] type)
-     (identifier? #'var)
-     (syntax/loc stx (define var (constant (list #'var (oracle #'var)) type)))]
-    [(_ var type)
-     (identifier? #'var)
-     (syntax/loc stx (define-symbolic* [var (current-oracle)] type))]
-    [(_ var type [ k ... ])
-     (and (identifier? #'var) (implies (identifier? #'type) (identifier-binding #'type)))
-     (syntax/loc stx (define var (reshape (list k ...) (for/list ([i (in-range (* k ...))])
+  (syntax-parse stx
+    [(_ var:id type)
+     #'(define var (constant (list #'var (index!)) type))]
+    [(_ var:id type #:length k)
+     #:declare k (expr/c #'natural? #:name "length argument")
+     #'(define var
+         (for/list ([i k.c])
            (define-symbolic* var type)
-                                                         var))))]
-    [(_ v0 v ... type)
-     (and (identifier? #'v0) (andmap identifier? (syntax->list #'(v ...))))
-     (syntax/loc stx (begin (define-symbolic* v0 type) (define-symbolic* v type) ...))]
-    ))
-
-#|--------------helper functions--------------|#
-
-(module util racket
-  (require racket/syntax)
-  (provide var-ids indices)
-  
-  (define (var-ids id-stx dim-spec [separator '@])
-    (for/list ([idx (apply indices (dims dim-spec))]) 
-      (format-id id-stx "~a~a~a" id-stx separator idx #:source id-stx)))
-  
-  (define (dims spec)
-    (begin0 spec
-            (for ([dim spec])
-              (unless (and (integer? dim) (>= dim 0))
-                (error 'define-symbolic "expected a non-negative integer, given ~a" dim)))))
-  
-  (define (indices . k) 
-    (cond [(null? k) k]
-          [(null? (cdr k)) (build-list (car k) (lambda (i) (format-symbol "~a" i)))]
-          [else (let ([car-idx (indices (car k))]
-                      [cdr-idx (apply indices (cdr k))])
-                  (append-map (lambda (i) 
-                                (map (lambda (j) 
-                                       (format-symbol "~a:~a" i j)) 
-                                     cdr-idx)) 
-                              car-idx))])))
-
-(require (for-syntax 'util) 'util)
-
-(define-for-syntax (define-array stx var type dims)
-  (with-syntax ([var var]
-                [type type]
-                [(k ...) dims])
-    (with-handlers ([exn:fail? 
-                     (lambda (e) 
-                       (case (syntax-local-context)
-                         [(module top-level) 
-                          (quasisyntax/loc stx 
-                            (define var (reshape (list k ...) 
-                                                 (map (lambda (id) (constant id type)) 
-                                                      (var-ids #'var (list k ...))))))]
-                         [else (raise e)]))])
-      (with-syntax ([(v ...) (var-ids #'var (eval #'(list k ...)))]) 
-        (quasisyntax/loc stx 
-          (define var (reshape (list k ...) (list (constant #'v type) ...))))))))
-  
+           var))]
+    [(_ var:id ...+ type)
+     #'(begin (define-symbolic* var type) ...)]))

rosette/base/form/module.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require (for-syntax racket/dict syntax/parse syntax/id-table (only-in racket pretty-print) 
+(require (for-syntax racket/dict syntax/parse syntax/parse/define syntax/id-table (only-in racket pretty-print)
                      (only-in "../core/lift.rkt" drop@))
          racket/require racket/undefined
          (filtered-in drop@ "../adt/box.rkt")
@@ -99,7 +99,14 @@
    [(var:id ...) (syntax->list stx)]
    [(var:id ... . rest:id) (syntax->list #'(var ... rest))]))
 
+(begin-for-syntax
+  (define-simple-macro (quasisyntax* orig-stx new-stx)
+    (let ([orig-stx* orig-stx]
+          [new-stx* (quasisyntax new-stx)])
+      (datum->syntax new-stx* (syntax-e new-stx*) orig-stx* orig-stx*))))
+
 (define-for-syntax (box-mutated-vars form tbl)
+  (define varref-tbl (make-free-id-table))
   (define (mutated? id) (free-id-table-ref tbl id #f))
   (define (any-mutated? ids) (for/or ([id ids]) (mutated? id)))
   (define (bmv/list lstx)
@@ -109,7 +116,7 @@
   
   (define (bmv/rest stx lit lstx)
     (let-values ([(pure? forms) (bmv/list lstx)])
-      (if pure? stx (quasisyntax/loc stx (#,lit #,@forms))))) 
+      (if pure? stx (quasisyntax* stx (#,lit #,@forms)))))
   
   (define (bmv/proc-body formals rest)
     (let-values ([(pure? fs) (bmv/list rest)]
@@ -126,33 +133,40 @@
      (syntax-disarm stx orig-insp) 
      #:literal-sets (kernel-literals)
      [var:id
-      (cond [(and (mutated? #'var) (lexical? #'var)) (syntax/loc stx (unbox var))]
+      (cond [(and (mutated? #'var) (lexical? #'var)) (quasisyntax* stx (unbox var))]
             [else #'var])]
      [(set! var expr) 
       (let ([e (bmv #'expr)])
-        (cond [(lexical? #'var) (quasisyntax/loc stx (set-box! var #,e))]
+        (cond [(lexical? #'var) (quasisyntax* stx (set-box! var #,e))]
               [(eq? e #'expr) stx]
-              [else (quasisyntax/loc stx (set! var #,e))]))]
+              [else (quasisyntax* stx (set! var #,e))]))]
      [(define-values (var) expr)
       (let ([e (bmv #'expr)])
         (cond [(mutated? #'var) 
                (with-syntax ([(loc) (generate-temporaries #'(var))])
-                 (quasisyntax/loc stx 
-                   (splicing-let ([loc (box #,e)])
+                 (dict-set! varref-tbl #'var #'loc)
+                 (quasisyntax* stx
+                   (begin
+                     (define loc (box #,e))
                      (define-syntax var
                        (syntax-id-rules (set!)
                          [(set! var val) (set-box! loc val)]
                          [(var . arg) ((unbox loc) . arg)]
                          [var (unbox loc)])))))]
               [(eq? e #'expr) stx]
-              [else (quasisyntax/loc stx (define-values (var) #,e))]))]
+              [else (quasisyntax* stx (define-values (var) #,e))]))]
      [(define-values (var ...) expr)
       (let ([e (bmv #'expr)]
             [vs (syntax->list #'(var ...))])
         (cond [(any-mutated? vs)
                (let ([locs (generate-temporaries vs)])
-                 (quasisyntax/loc stx 
-                   (splicing-let-values ([#,locs #,e])
+                 (for ([v (in-list vs)]
+                       [loc (in-list locs)]
+                       #:when (mutated? v))
+                   (dict-set! varref-tbl v loc))
+                 (quasisyntax* stx
+                   (begin
+                     (define-values #,locs #,e)
                      #,@(for/list ([v vs][loc locs] #:when (mutated? v))
                           #`(set! #,loc (box #,loc)))
                      #,@(for/list ([v vs][loc locs])
@@ -164,14 +178,14 @@
                                     [#,v (unbox #,loc)]))
                               #`(define-values (#,v) #,loc))))))]
               [(eq? e #'expr) stx]
-              [else (quasisyntax/loc stx (define-values (var ...) #,e))]))]
+              [else (quasisyntax* stx (define-values (var ...) #,e))]))]
      [(let-values ([(var ...) expr] ...) body ...)
       (let-values ([(pure-es? es) (bmv/list #'(expr ...))]
                    [(pure-fs? fs) (bmv/list #'(body ...))]
                    [(vs) (syntax->list #'(var ... ...))])
         (cond [(any-mutated? vs)
                (with-syntax ([(e ...) es])
-                 (quasisyntax/loc stx
+                 (quasisyntax* stx
                    (let-values ([(var ...) e] ...)
                      #,@(for/list ([v vs] #:when (mutated? v))
                           #`(set! #,v (box #,v))) 
@@ -179,7 +193,7 @@
               [(and pure-es? pure-fs?) stx]
               [else 
                (with-syntax ([(e ...) es])
-                 (quasisyntax/loc stx
+                 (quasisyntax* stx
                    (let-values ([(var ...) e] ...)
                      #,@fs)))]))]
      [(letrec-values ([(var ...) expr] ...) body ...) 
@@ -188,7 +202,7 @@
                    [(vs) (syntax->list #'(var ... ...))])
         (cond [(any-mutated? vs)
                (let ([ves (syntax->list #'((var ...) ...))])
-                 (quasisyntax/loc stx
+                 (quasisyntax* stx
                    (letrec-values ([#,vs (apply values (make-list #,(length vs) undefined))])
                      #,@(for/list ([v vs] #:when (mutated? v))
                           #`(set! #,v (box #,v)))
@@ -201,7 +215,7 @@
               [(and pure-es? pure-fs?) stx]
               [else 
                (with-syntax ([(e ...) es])
-                 (quasisyntax/loc stx
+                 (quasisyntax* stx
                    (letrec-values ([(var ...) e] ...)
                      #,@fs)))]))]
      [(letrec-syntaxes+values stx-decls ([(var ...) expr] ...) body ...) 
@@ -210,7 +224,7 @@
                     [(vs) (syntax->list #'(var ... ...))])
         (cond [(any-mutated? vs)
                (let ([ves (syntax->list #'((var ...) ...))])
-                 (quasisyntax/loc stx  
+                 (quasisyntax* stx
                    (letrec-syntaxes+values stx-decls ([#,vs (apply values (make-list #,(length vs) undefined))])
                      #,@(for/list ([v vs] #:when (mutated? v))
                           #`(set! #,v (box #,v)))
@@ -223,13 +237,13 @@
               [(and pure-es? pure-fs?) stx]
               [else 
                (with-syntax ([(e ...) es])
-                 (quasisyntax/loc stx
+                 (quasisyntax* stx
                    (letrec-syntaxes+values stx-decls ([(var ...) e] ...)
                      #,@fs)))]))]
      [(#%plain-lambda formals . rest)
       (let ([body (bmv/proc-body #'formals #'rest)])
         (cond [(eq? body #'rest) stx]
-              [else (quasisyntax/loc stx (#%plain-lambda formals #,@body))]))]
+              [else (quasisyntax* stx (#%plain-lambda formals #,@body))]))]
      [(case-lambda . rest)
       (let* ([r (syntax->list #'rest)]
              [fs (for/list ([fb r])
@@ -237,16 +251,19 @@
                     (let ([body (bmv/proc-body #'f #'b)])
                       (if (eq? body #'b)
                           fb 
-                          (quasisyntax/loc fb (f #,@body))))))])
+                          (quasisyntax* fb (f #,@body))))))])
         (cond [(equal? r fs) stx]
-              [else (quasisyntax/loc stx (case-lambda #,@fs))]))]      
+              [else (quasisyntax* stx (case-lambda #,@fs))]))]
      [(if . rest) (bmv/rest stx #'if #'rest)]
      [(#%expression . rest) (bmv/rest stx #'#%expression #'rest)]
      [(#%plain-app . rest)  (bmv/rest stx #'#%plain-app #'rest)]
      [(begin . rest)  (bmv/rest stx #'begin #'rest)]
      [(begin0 . rest) (bmv/rest stx #'begin0 #'rest)]
      [(with-continuation-mark . rest) (bmv/rest stx #'with-continuation-mark #'rest)]
-     [(#%plain-module-begin . rest) (quasisyntax/loc stx (#%module-begin #,@(map bmv (syntax->list #'rest))))]
+     [(#%plain-module-begin . rest) (quasisyntax* stx (#%module-begin #,@(map bmv (syntax->list #'rest))))]
+     [(#%variable-reference x)
+      #`(#%variable-reference
+         #,(free-id-table-ref varref-tbl #'x (λ () #'x)))]
      [_ stx]))
   
     (bmv form))

rosette/base/form/state.rkt

@@ -1,29 +0,0 @@
-#lang racket
-
-(provide current-oracle oracle? (rename-out [make-oracle oracle]))
-
-#|--------------current state parameters--------------|#
-
-(struct oracle ([tbl])
-  #:property prop:procedure
-  (lambda (self var)
-    (let* ([vars (oracle-tbl self)]
-           [choice-idx (hash-ref vars var 0)])
-      (hash-set! vars var (+ choice-idx 1))
-      choice-idx))
-  #:methods gen:custom-write
-  [(define (write-proc self port mode) 
-     (fprintf port "oracle~a" (oracle-tbl self)))])
-
-(define make-oracle
-  (case-lambda 
-    [() (oracle (make-hash))]
-    [(other) (oracle (hash-copy (oracle-tbl other)))]))
-
-(define current-oracle
-  (make-parameter (make-oracle)
-                  (lambda (oracle)
-                    (unless (oracle? oracle)
-                      (error 'current-oracle "expected an oracle procedure, given ~s" oracle))
-                    oracle)))
-

rosette/base/struct/struct-type.rkt

@@ -3,7 +3,7 @@
 
 (require (for-syntax "../core/lift.rkt" racket/syntax)
          (only-in racket/private/generic-methods generic-property)
-         (only-in "../core/effects.rkt" apply!)
+         (only-in "../core/store.rkt" store!)
          "../core/term.rkt"  "../core/lift.rkt" "../core/safe.rkt"
          (only-in "../core/bool.rkt" || && and-&&)
          (only-in "../core/type.rkt" @any/c type-cast gen:typed get-type)
@@ -80,33 +80,43 @@
   
   (values struct:t make-t @struct:t t-ref t-set!))
 
+(define (struct-field-accessor-name @struct:t i field-id)
+  (if field-id
+      (format "~a-~a" (object-name (struct-type-make @struct:t)) field-id)
+      (format "~a-field~a" (object-name (struct-type-make @struct:t)) i)))
+
+(define (struct-field-mutator-name @struct:t i field-id)
+  (format "set-~a!" (struct-field-accessor-name @struct:t i field-id)))
+  
 (define (@make-struct-field-mutator struct:t i field-id)
   (let* ([@struct:t (get-type struct:t)]
          [native? (struct-type-native? @struct:t)]
-         [setter (make-struct-field-mutator (struct-type-set! @struct:t) i field-id)]
-         [getter (make-struct-field-accessor (struct-type-ref @struct:t) i field-id)])
+         [name (string->symbol (struct-field-mutator-name @struct:t i field-id))]
+         [setter (struct-type-set! @struct:t)]
+         [getter (struct-type-ref @struct:t)])
     (procedure-rename 
      (lambda (receiver value)  
        (if (native? receiver)
-           (apply! setter getter receiver value) 
-           (match (type-cast @struct:t receiver (object-name setter))
-             [(? native? r) (apply! setter getter r value)]
+           (store! receiver i value getter setter) 
+           (match (type-cast @struct:t receiver name)
+             [(? native? r) (store! r i value getter setter)]
              [(union rs) (for ([r rs])
-                           (apply! setter getter (cdr r) (merge (car r) value (getter (cdr r)))))])))
-     (object-name setter))))
+                           (store! (cdr r) i (merge (car r) value (getter (cdr r) i)) getter setter))])))
+     name)))
 
 (define (@make-struct-field-accessor struct:t i field-id)
   (let* ([@struct:t (get-type struct:t)]
          [native? (struct-type-native? @struct:t)]
-         [getter (make-struct-field-accessor (struct-type-ref @struct:t) i field-id)])
+         [name (string->symbol (struct-field-accessor-name @struct:t i field-id))]
+         [getter (struct-type-ref @struct:t)])
     (procedure-rename 
      (lambda (receiver) 
        (if (native? receiver)
-           (getter receiver)
-           (match (type-cast @struct:t receiver (object-name getter))
-             [(? native? r) (getter r)]
-             [(union r) (merge** r getter)])))
-     (object-name getter))))
+           (getter receiver i)
+           (match (type-cast @struct:t receiver name)
+             [(? native? r) (getter r i)]
+             [(union r) (merge** r (getter _ i))])))
+     name)))
 
 (struct struct-type (pred super native? make ref set! fields immutable? transparent? procedure? equal+hash)
   #:property prop:procedure

rosette/base/util/array.rkt

@@ -1,76 +0,0 @@
-#lang racket
-
-(require racket/syntax racket/splicing )
-(provide define-array array-procedure reshape split-at* list-ref*)
-
-; Provides a macro for defining multidimensional arrays.  The 
-; form (define-array var dims vals) defines a multidimensional 
-; array from a dimension specification and a flat list of values.  The macro 
-; introduces a name transformer var.  When used as an identifer
-; the var transformer returns the array in the form of a list of 
-; lists.  When used as a function, it takes a sequence of indices
-; and returns the element (or a subarray) at the specified position. 
-; 
-; The dimension specification should be list of positive natural 
-; numbers.  For example, '(3 2 3) specifies a 3x2x3 array.  The 
-; vals list should contain exactly (apply * dims) values.
-;
-; The form (define-array var vals) assumes that vals is already a 
-; list of lists.  It simply introduces a name transformer for var, 
-; as described above.
-(define-syntax (define-array stx)
-  (syntax-case stx ()
-    [(_ id dims vals) 
-      #`(define-array id (reshape dims vals))]
-    [(_ id vals) 
-     #`(splicing-let ([array (array-procedure vals)])
-         (define-syntax id
-           (syntax-id-rules (set!)
-             [(set! id e) 
-              (error 'set! "cannot modify an immutable reference: ~s" (syntax->datum #'id))]
-             [(id idx (... ...)) (array idx (... ...))]
-             [id (array)])))]))
-
-; This macro expands to a procedure wrapper that allows
-; the elements in the given nested list representation of 
-; an array to be accessed using a call of the form (vals idx ...).
-; Applying the resulting procedure to no arguments yields the 
-; entire array (that is, list of lists).
-(define-syntax-rule (array-procedure vals)
-  (let ([array vals])
-    (procedure-rename
-     (lambda pos
-       (apply list-ref* array pos))
-     (string->symbol (format "array~aD" (length array))))))
-
-; This function returns a nested list representation 
-; of the given flat list using the given shape specification.
-; The shape specification is a flat list of positive natural 
-; numbers.  For example, '(3 2) specifies a nested list that 
-; corresponds to a 3x2 array in row major order, i.e., 
-; (reshape '(3 2) '(0 1 2 3 4 5)) yields  '((0 1 2) (3 4 5)).  
-; The behavior of this function is unspecified if the length of 
-; the vals list is not exactly (apply * dims).   
-(define (reshape dims vals)
-  (cond [(null? dims) null]
-        [(null? (cdr dims)) vals] 
-        [else (let ([rest (cdr dims)])
-                (map (curry reshape (cdr dims)) (split-at* vals (apply * rest))))]))
-
-; Splits a list of size k*n into k sublists of size n.  The 
-; sublists are returned in a list.  The behavior of this function 
-; is unspecified if the length of the list is not a multiple of n.  
-(define (split-at* vals n)
-  (if (null? vals) 
-      null
-      (let-values ([(left right) (split-at vals n)])
-        (cons left (split-at* right n)))))
-
-; Returns the value in the given nested list representation of a 
-; mulitdimensional array that is at the specified position.  The 
-; value itself may be a list; for example, (list-ref* '((0 1) (2 3)) 0)
-; produces '(0 1) while (list-ref* '((0 1) (2 3)) 1 0) produces 2.
-(define (list-ref* vals . pos)
-  (if (null? pos)
-      vals
-      (apply list-ref* (list-ref vals (car pos)) (cdr pos))))

rosette/base/util/ord-dict.rkt

@@ -1,51 +0,0 @@
-#lang racket
-
-(provide odict? (rename-out [make-odict odict]))
-
-(struct odict (tbl [ord #:mutable] eq)
-  #:methods gen:dict
-    [(define (dict-ref dict key [default (lambda () (error "key not found" key))])
-       (hash-ref (odict-tbl dict) key default))
-
-     (define (dict-set! dict key val)
-       (match-define (odict tbl ord _) dict)
-       (unless (hash-has-key? tbl key)
-         (set-odict-ord! dict (cons key ord)))
-       (hash-set! tbl key val))
-
-     (define (dict-remove! dict key)
-       (match-define (odict tbl ord eq) dict)
-       (when (hash-has-key? tbl key)
-         (hash-remove! tbl key)
-         (set-odict-ord! dict (remove key ord eq))))
-
-     (define (dict-iterate-first dict)
-       (match-define (odict _ ord _) dict)
-       (and (not (null? ord)) ord))
-
-     (define (dict-iterate-next dict pos)
-       (and (> (length pos) 1) (cdr pos)))
-
-     (define (dict-iterate-key dict pos)
-       (car pos))
-
-     (define (dict-iterate-value dict pos)
-       (hash-ref (odict-tbl dict) (car pos)))
-
-     (define (dict-count dict)
-       (hash-count (odict-tbl dict)))
-
-     (define (dict-has-key dict key)
-       (hash-has-key? (odict-tbl dict) key))
-     ])
-
-(define (make-odict [assocs null] [is-equal? equal?])
-  (define make-table
-    (match is-equal?
-      [(== equal?) make-hash]
-      [(== eq?) make-hasheq]
-      [(== eqv?) make-hasheqv]
-      [_ (error 'odict "expected equal?, eq?, or eqv? equivalence predicate, given ~a" is-equal?)]))
-  (odict (make-table assocs) (map car assocs) is-equal?))
-
-   

rosette/guide/scribble/datatypes/bitvectors.scrbl

@@ -1,7 +1,7 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/query/form rosette/query/eval rosette/solver/solution
+           rosette/base/form/define  
            rosette/base/core/term 
            (only-in rosette/base/core/union union?)
            (only-in rosette/base/base bv bv? bitvector bitvector? bitvector-size
@@ -13,11 +13,10 @@
                     bit lsb msb bvzero? bvadd1 bvsub1
                     bvsmin bvsmax bvumin bvumax
                     rotate-left rotate-right bvrol bvror
-                    bool->bitvector bitvector->bool bitvector->bits)
-           (only-in rosette/base/core/safe assert) 
-           (only-in rosette/base/core/bool asserts))
+                    bool->bitvector bitvector->bool bitvector->bits
+                    assert vc))
           (for-label racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+          scribble/core scribble/html-properties scribble/examples racket/sandbox
           "../util/lifted.rkt")
 
 
@@ -37,19 +36,21 @@ Technically, Rosette's bitvector datatype embeds the
 into a programming language.
 
 @examples[#:eval rosette-eval
-(code:line (bv 4 (bitvector 7))        (code:comment "a bitvector literal of size 7"))
-(code:line (bv 4 7)                    (code:comment "a shorthand for the same literal"))
-(code:line (define-symbolic x y (bitvector 7)) (code:comment "symbolic bitvector constants"))
-(code:line (bvslt (bv 4 7) (bv -1 7))  (code:comment "signed 7-bit < comparison of 4 and -1"))
-(code:line (bvult (bv 4 7) (bv -1 7))  (code:comment "unsigned 7-bit < comparison of 4 and -1"))
+(code:line (bv 4 (bitvector 7))        (code:comment "A bitvector literal of size 7."))
+(code:line (bv 4 7)                    (code:comment "A shorthand for the same literal."))
+(code:line (define-symbolic x y (bitvector 7)) (code:comment "Symbolic bitvector constants."))
+(code:line (bvslt (bv 4 7) (bv -1 7))  (code:comment "Signed 7-bit < comparison of 4 and -1."))
+(code:line (bvult (bv 4 7) (bv -1 7))  (code:comment "Unsigned 7-bit < comparison of 4 and -1."))
 (define-symbolic b boolean?)
-(code:line (bvadd x (if b y (bv 3 4))) (code:comment "this typechecks only when b is true"))
-(code:line (asserts)                   (code:comment "so Rosette emits a corresponding assertion"))]
+(code:line (bvadd x (if b y (bv 3 4))) (code:comment "This typechecks only when b is true,"))
+(code:line (vc)                        (code:comment "so Rosette emits a corresponding assertion."))]
 
 @defproc[(bitvector [size (and/c integer? positive? (not/c term?) (not/c union?))]) bitvector?]{
+                                                                                                
   Returns a type predicate that recognizes bitvectors of the given @racket[size].
   Note that @racket[size] must be a concrete positive integer.                                                        
   The type predicate itself is recognized by the @racket[bitvector?] predicate.
+  
   @examples[#:eval rosette-eval
    (define bv6? (bitvector 6))
    (bv6? 1)
@@ -60,15 +61,17 @@ into a programming language.
 }
 
 @defproc[(bitvector? [v any/c]) boolean?]{
+                                          
   Returns true if @racket[v] is a concrete type predicate that recognizes bitvector values.
+                  
    @examples[#:eval rosette-eval
    (define bv6? (bitvector 6))
    (define bv7? (bitvector 7))
    (define-symbolic b boolean?)
-   (code:line (bitvector? bv6?) (code:comment "a concrete bitvector type"))
-   (code:line (bitvector? (if b bv6? bv7?)) (code:comment "not a concrete type"))
-   (code:line (bitvector? integer?) (code:comment "not a bitvector type"))
-   (code:line (bitvector? 3) (code:comment "not a type"))]}
+   (code:line (bitvector? bv6?)             (code:comment "A concrete bitvector type."))
+   (code:line (bitvector? (if b bv6? bv7?)) (code:comment "Not a concrete type."))
+   (code:line (bitvector? integer?)         (code:comment "Not a bitvector type."))
+   (code:line (bitvector? 3)                (code:comment "Not a type."))]}
 
 @defproc[(bv [val (and/c integer? (not/c term?) (not/c union?))]
              [size (and/c (or/c bitvector? (and/c integer? positive?))
@@ -86,7 +89,7 @@ into a programming language.
    (bv? (if b (bv 3 6) #t))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @section{Comparison Operators}
 
@@ -99,71 +102,83 @@ into a programming language.
            [(bvugt [x (bitvector n)] [y (bitvector n)]) boolean?]
            [(bvsge [x (bitvector n)] [y (bitvector n)]) boolean?]
            [(bvuge [x (bitvector n)] [y (bitvector n)]) boolean?])]{
+                                                                    
 Compares two bitvector values of the same bitvector type. 
 Comparison relations include 
 equality (@racket[bveq]) and signed / unsigned versions of
 <, <=, >, and >= (@racket[bvslt], @racket[bvult], @racket[bvsle], @racket[bvule],
 @racket[bvsgt], and @racket[bvugt]).
+
 @examples[#:eval rosette-eval
-(code:line (define-symbolic u v (bitvector 7)) (code:comment "symbolic bitvector constants"))
-(code:line (bvslt (bv 4 7) (bv -1 7))  (code:comment "signed 7-bit < comparison of 4 and -1"))
-(code:line (bvult (bv 4 7) (bv -1 7))  (code:comment "unsigned 7-bit < comparison of 4 and -1"))
+(code:line (define-symbolic u v (bitvector 7)) (code:comment "Symbolic bitvector constants."))
+(code:line (bvslt (bv 4 7) (bv -1 7))  (code:comment "Signed 7-bit < comparison of 4 and -1."))
+(code:line (bvult (bv 4 7) (bv -1 7))  (code:comment "Unsigned 7-bit < comparison of 4 and -1."))
 (define-symbolic b boolean?)
-(code:line (bvsge u (if b v (bv 3 4))) (code:comment "this typechecks only when b is true"))
-(code:line (asserts)                   (code:comment "so Rosette emits a corresponding assertion"))]
+(code:line (bvsge u (if b v (bv 3 4))) (code:comment "This typechecks only when b is true,"))
+(code:line (vc)                        (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @section{Bitwise Operators}
 
 @defproc[(bvnot [x (bitvector n)]) (bitvector n)]{
+                                                  
  Returns the bitwise negation of the given bitvector value.
+ 
  @examples[#:eval rosette-eval
  (bvnot (bv -1 4))
  (bvnot (bv 0 4))
  (define-symbolic b boolean?)
- (code:line (bvnot (if b 0 (bv 0 4))) (code:comment "this typechecks only when b is false"))
- (code:line (asserts)                 (code:comment "so Rosette emits a corresponding assertion"))]
+ (code:line (bvnot (if b 0 (bv 0 4))) (code:comment "This typechecks only when b is false,"))
+ (code:line (vc)                      (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bvand [x (bitvector n)] ...+) (bitvector n)]
            [(bvor  [x (bitvector n)] ...+) (bitvector n)]
            [(bvxor [x (bitvector n)] ...+) (bitvector n)])]{
-Returns the bitwise "and", "or", "xor" of one or more bitvector values of the same type.
+                                                            
+Returns the bitwise ``and'', ``or'', ``xor'' of one or more bitvector values of the same type.
+
  @examples[#:eval rosette-eval
  (bvand (bv -1 4) (bv 2 4))
  (bvor  (bv 0 3)  (bv 1 3))
  (bvxor (bv -1 5) (bv 1 5))
  (define-symbolic b boolean?)
- (code:line (bvand (bv -1 4)
-                   (if b 0 (bv 2 4))) (code:comment "this typechecks only when b is false"))
- (code:line (asserts)                 (code:comment "so Rosette emits a corresponding assertion"))]
+ (code:line
+  (bvand (bv -1 4)
+         (if b 0 (bv 2 4))) (code:comment "This typechecks only when b is false,"))
+ (code:line
+  (vc)                      (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
   
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @defproc*[([(bvshl  [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvlshr [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvashr [x (bitvector n)] [y (bitvector n)]) (bitvector n)])]{
+                                                                          
 Returns the left, logical right, or arithmetic right shift of @racket[x]  by
 @racket[y] bits, where @racket[x] and @racket[y] are bitvector values of the same type.
+
  @examples[#:eval rosette-eval
  (bvshl  (bv 1 4) (bv 2 4))
  (bvlshr (bv -1 3) (bv 1 3))
  (bvashr (bv -1 5) (bv 1 5))
  (define-symbolic b boolean?)
  (code:line (bvshl (bv -1 4)
-                   (if b 0 (bv 2 4))) (code:comment "this typechecks only when b is false"))
- (code:line (asserts)                 (code:comment "so Rosette emits a corresponding assertion"))]
+                   (if b 0 (bv 2 4))) (code:comment "This typechecks only when b is false,"))
+ (code:line (vc)                      (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
 @section{Arithmetic Operators}
 
 @defproc[(bvneg [x (bitvector n)]) (bitvector n)]{
+                                                  
  Returns the arithmetic negation of the given bitvector value.
+ 
  @examples[#:eval rosette-eval
  (bvneg (bv -1 4))
  (bvneg (bv 0 4))
@@ -171,46 +186,52 @@ Returns the left, logical right, or arithmetic right shift of @racket[x]  by
  (bvneg z)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @(rosette-eval '(clear-terms!))
 
 @defproc*[([(bvadd [x (bitvector n)] ...+) (bitvector n)]
            [(bvsub [x (bitvector n)] ...+) (bitvector n)]
            [(bvmul [x (bitvector n)] ...+) (bitvector n)])]{
+                                                            
 Returns the sum, difference, or product of one or more bitvector values of the same type.
+
  @examples[#:eval rosette-eval
  (bvadd (bv -1 4) (bv 2 4))
  (bvsub (bv 0 3)  (bv 1 3))
  (bvmul (bv -1 5) (bv 1 5))
  (define-symbolic b boolean?)
  (bvadd (bv -1 4) (bv 2 4) (if b (bv 1 4) "bad"))
- (asserts)]
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bvsdiv [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvudiv [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvsrem [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvurem [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvsmod [x (bitvector n)] [y (bitvector n)]) (bitvector n)])]{
+                                                                          
 Returns (un)signed quotient, remainder, or modulo of two bitvector values of the same type.
 All five operations are defined even when the second argument is zero.
+
  @examples[#:eval rosette-eval
  (bvsdiv (bv -3 4) (bv 2 4))
  (bvudiv (bv -3 3) (bv 2 3))
  (bvsmod (bv 1 5) (bv 0 5))
  (define-symbolic b boolean?)
  (bvsrem (bv -3 4) (if b (bv 2 4) "bad"))
- (asserts)]
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @section{Conversion Operators}
 
 @defproc[(concat [x bv?] ...+) bv?]{
+                                    
  Returns the bitwise concatenation of the given bitvector values.
+ 
  @examples[#:eval rosette-eval
  (concat (bv -1 4) (bv 0 1) (bv -1 3))
  (define-symbolic b boolean?)
@@ -218,89 +239,96 @@ All five operations are defined even when the second argument is zero.
 }
 
 @defproc[(extract [i integer?] [j integer?] [x (bitvector n)]) (bitvector (+ 1 (- i j)))]{
+                                                                                          
  Extracts bits @racket[i] down to @racket[j] from a bitvector of size @racket[n], yielding a
  bitvector of size i - j + 1.  This procedure assumes that @racket[n] > @racket[i] >= @racket[j] >= 0.
+ 
  @examples[#:eval rosette-eval
  (extract 2 1 (bv -1 4))
  (extract 3 3 (bv 1 4))
  (define-symbolic i j integer?)
- (eval:alts (extract i j (bv 1 2)) (begin (extract i j (bv 1 2)) "{[(&& (= 0 j) (= 1 i)) (bv 1 2)] ...}"))
- (asserts)]
+ (extract i j (bv 1 2)) 
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(sign-extend [x bv?] [t (or/c bitvector? union?)]) bv?]
            [(zero-extend [x bv?] [t (or/c bitvector? union?)]) bv?])]{
+                                                                      
 Returns a bitvector of type @racket[t] that represents the (un)signed
 extension of the bitvector @racket[x].
 Note that both @racket[x] and @racket[t] may be symbolic. The size of @racket[t]
 must not be smaller than the size of @racket[x]'s type.
+
  @examples[#:eval rosette-eval
  (sign-extend (bv -3 4) (bitvector 6))
  (zero-extend (bv -3 4) (bitvector 6))
  (define-symbolic b c boolean?)
  (zero-extend (bv -3 4) (if b (bitvector 5) (bitvector 6)))
  (zero-extend (bv -3 4) (if b (bitvector 5) "bad"))
- (asserts)
+ (vc)
  (zero-extend (bv -3 4) (if c (bitvector 5) (bitvector 1)))
- (asserts)]
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bitvector->integer [x bv?]) integer?]
            [(bitvector->natural [x bv?]) integer?])]{
+                                                     
 Returns the (un)signed integer value of the given bitvector.
+
  @examples[#:eval rosette-eval
  (bitvector->integer (bv -1 4))
  (bitvector->natural (bv -1 4))
  (define-symbolic b boolean?)
  (bitvector->integer (if b (bv -1 3) (bv -3 4)))
  (bitvector->integer (if b (bv -1 3) "bad"))
- (asserts)]
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(integer->bitvector [i integer?] [t (or/c bitvector? union?)]) bv?])]{
+                                                                                  
 Returns a bitvector of type @racket[t] that represents the @var[k] lowest order bits
 of the integer @racket[i], where @var[k] is the size of @racket[t].              
 Note that both @racket[i] and @racket[t] may be symbolic.
+
  @examples[#:eval rosette-eval
  (integer->bitvector 4 (bitvector 2))
  (integer->bitvector 15 (bitvector 4))
  (define-symbolic b c boolean?)
  (integer->bitvector (if b pi 3) (if c (bitvector 5) (bitvector 6)))
- (asserts)]
+ (vc)]
 }
 
 @section{Additional Operators}
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(bit [i integer?] [x (bitvector n)]) (bitvector 1)]{
+                                                             
  Extracts the @racket[i]th bit from the bitvector @racket[x] of size @racket[n], yielding a
  bitvector of size 1.  This procedure assumes that @racket[n] > @racket[i] >= 0.
+ 
  @examples[#:eval rosette-eval
  (bit 1 (bv 3 4))
  (bit 2 (bv 1 4))
  (define-symbolic i integer?)
  (define-symbolic x (bitvector 4))
- (eval:alts (bit i x)
-            (begin (bit i x)
-"(ite* (⊢ (= 0 i) (extract 0 0 x))
-      (⊢ (= 1 i) (extract 1 1 x))
-      (⊢ (= 2 i) (extract 2 2 x))
-      (⊢ (= 3 i) (extract 3 3 x))))"))
- (asserts)]
+ (bit i x) 
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(lsb [x (bitvector n)]) (bitvector 1)]
            [(msb [x (bitvector n)]) (bitvector 1)])]{
+                                                     
  Returns the least or most significant bit of @racket[x].
+                                              
  @examples[#:eval rosette-eval
   (lsb (bv 3 4))
   (msb (bv 3 4))
@@ -311,10 +339,12 @@ Note that both @racket[i] and @racket[t] may be symbolic.
   ]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(bvzero? [x (bitvector n)]) boolean?]{
+                                               
 Returns @racket[(bveq x (bv 0 n))].
+        
  @examples[#:eval rosette-eval
   (define-symbolic x (bitvector 4))
   (bvzero? x)
@@ -325,11 +355,13 @@ Returns @racket[(bveq x (bv 0 n))].
  ]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bvadd1 [x (bitvector n)]) (bitvector n)]
            [(bvsub1 [x (bitvector n)]) (bitvector n)])]{
+                                                        
  Returns @racket[(bvadd x (bv 1 n))] or @racket[(bvsub x (bv 1 n))].
+         
  @examples[#:eval rosette-eval
   (define-symbolic x (bitvector 4))
   (bvadd1 x)
@@ -342,13 +374,15 @@ Returns @racket[(bveq x (bv 0 n))].
 }
 
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bvsmin [x (bitvector n)] ...+) (bitvector n)]
            [(bvumin [x (bitvector n)] ...+) (bitvector n)]
            [(bvsmax [x (bitvector n)] ...+) (bitvector n)]
            [(bvumax [x (bitvector n)] ...+) (bitvector n)])]{
+                                                             
 Returns the (un)signed minimum or maximum of one or more bitvector values of the same type.
+
  @examples[#:eval rosette-eval
  (bvsmin (bv -1 4) (bv 2 4))
  (bvumin (bv -1 4) (bv 2 4))
@@ -356,72 +390,74 @@ Returns the (un)signed minimum or maximum of one or more bitvector values of the
  (bvumax (bv -1 4) (bv 2 4))
  (define-symbolic b boolean?)
  (bvsmin (bv -1 4) (bv 2 4) (if b (bv 1 4) (bv 3 8)))
- (asserts)]
+ (vc)]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(bvrol [x (bitvector n)] [y (bitvector n)]) (bitvector n)]
            [(bvror [x (bitvector n)] [y (bitvector n)]) (bitvector n)])]{
+                                                                         
 Returns the left or right rotation of @racket[x] by @racket[(bvurem y n)] bits, where
 @racket[x] and @racket[y] are bitvector values of the same type.
+
  @examples[#:eval rosette-eval
  (bvrol (bv 3 4) (bv 2 4))
  (bvrol (bv 3 4) (bv -2 4))
  (define-symbolic b boolean?)
- (code:line (bvror (bv 3 4)
-                   (if b 0 (bv 2 4))) (code:comment "this typechecks only when b is false"))
- (code:line (asserts)                 (code:comment "so Rosette emits a corresponding assertion"))]
+ (code:line
+  (bvror (bv 3 4)
+         (if b 0 (bv 2 4))) (code:comment "This typechecks only when b is false,"))
+ (code:line
+  (vc)                      (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(rotate-left  [i integer?] [x (bitvector n)]) (bitvector n)]
            [(rotate-right [i integer?] [x (bitvector n)]) (bitvector n)])]{
+                                                                           
 Returns the left or right rotation of @racket[x] by @racket[i] bits.
 These procedures assume that @racket[n] > @racket[i] >= 0. See @racket[bvrol]
 and @racket[bvror] for an alternative way to perform rotations that usually
 leads to faster solving times.
+
  @examples[#:eval rosette-eval
  (rotate-left 3 (bv 3 4))
  (rotate-right 1 (bv 3 4))
  (define-symbolic i integer?)
  (define-symbolic b boolean?)
- (eval:alts (rotate-left i (if b (bv 3 4) (bv 7 8)))
-           (begin
  (rotate-left i (if b (bv 3 4) (bv 7 8))) 
-"{[b (ite* (⊢ (= 0 i) (bv #x3 4)) (⊢ (= 1 i) (bv #x6 4)) (⊢ (= 2 ...) ...) ...)]
- [(! b) (ite* (⊢ (= 0 i) (bv #x07 8)) (⊢ (= 1 i) (bv #x0e 8)) (⊢ (= ...) ...) ...)]}"))
- (asserts)
+ (vc)
  ]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
+
+@defproc[(bitvector->bits [x (bitvector n)]) (listof (bitvector 1))]{
                                                                      
-@defproc[(bitvector->bits [x (bitvector n)]) (listof (bitvector n))]{
 Returns the bits of @racket[x] as a list, i.e., @racket[(list (bit 0 x) ... (bit (- n 1) x))].
+                    
  @examples[#:eval rosette-eval
   (bitvector->bits (bv 3 4))
   (define-symbolic y (bitvector 2))
   (bitvector->bits y)
   (define-symbolic b boolean?)
-  (eval:alts (bitvector->bits (if b (bv 3 4) y))
-"{[b ((bv #b1 1) (bv #b1 1) (bv #b0 1) (bv #b0 1))]
- [(! b) ((extract 0 0 y) (extract 1 1 y))]}")
-
- ]
+  (bitvector->bits (if b (bv 3 4) y)) ]
 }
 
 @defproc[(bitvector->bool [x (bitvector n)]) boolean?]{
 Returns @racket[(not (bvzero? x))].
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(bool->bitvector [b any/c] [t (or/c positive-integer? (bitvector n)) (bitvector 1)]) bv?]{
+                                                                                                   
 Returns @racket[(bv 0 t)] if @racket[(false? b)] and otherwise returns @racket[(bv 1 t)], where
 @racket[t] is @racket[(bitvector 1)] by default. If provided, @racket[t] must be a concrete positive
 integer or a concrete bitvector type value.
+
  @examples[#:eval rosette-eval
   (bool->bitvector #f 3)
   (bool->bitvector "non-false-value")

rosette/guide/scribble/datatypes/bools+ints+reals.scrbl

@@ -1,13 +1,12 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/query/form rosette/query/eval rosette/solver/solution
+           rosette/base/form/define rosette/query/form rosette/query/query rosette/solver/solution
            rosette/base/core/term (only-in rosette/query/finitize current-bitwidth)
-           (only-in rosette/base/base ! && || => <=> exists forall function?)
-           (only-in rosette/base/core/safe assert) 
-           (only-in rosette/base/core/bool asserts with-asserts))
+           (only-in rosette/base/base ! && || => <=> exists forall function? assert vc with-vc
+                                      result-state result-value))
           (except-in (for-label racket) =>)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 
@@ -16,7 +15,7 @@
 
 @(define bools (select '(boolean? false? true false boolean=? not nand nor implies xor)))
 
-@(define nums (select '(number? complex? real? rational? integer? exact-integer? exact-nonnegative-integer? exact-positive-integer? inexact-real? fixnum? flonum? double-flonum? single-flonum? zero? positive? negative? even? odd? exact? inexact? inexact->exact exact->inexact real->single-flonum real->double-flonum + - * / quotient remainder quotient/ modulo add1 sub1 abs max min gcd lcm round floor ceiling truncate numerator denominator rationalize = < <= > >= sqrt integer-sqrt integer-sqrt/ expt exp log sin cos tan asin acos atan make-rectangular make-polar real-part imag-part magnitude angle bitwise-ior bitwise-and bitwise-xor bitwise-not bitwise-bit-set? bitwise-bit-field arithmetic-shift integer-length random random-seed make-pseudo-random-generator pseudo-random-generator? current-pseudo-random-generator pseudo-random-generator->vector vector->pseudo-random-generator vector->pseudo-random-generator! pseudo-random-generator-vector? number->string string->number real->decimal-string integer-bytes->integer integer->integer-bytes floating-point-bytes->real real->floating-point-bytes system-big-endian? pi pi.f degrees->radians radians->degrees sqr sgn conjugate sinh cosh tanh exact-round exact-floor exact-ceiling exact-truncate order-of-magnitude nan? infinite?)))
+@(define nums (select (remove* '(expt) '(number? complex? real? rational? integer? exact-integer? exact-nonnegative-integer? exact-positive-integer? inexact-real? fixnum? flonum? double-flonum? single-flonum? zero? positive? negative? even? odd? exact? inexact? inexact->exact exact->inexact real->single-flonum real->double-flonum + - * / quotient remainder quotient/ modulo add1 sub1 abs max min gcd lcm round floor ceiling truncate numerator denominator rationalize = < <= > >= sqrt integer-sqrt integer-sqrt/ expt exp log sin cos tan asin acos atan make-rectangular make-polar real-part imag-part magnitude angle bitwise-ior bitwise-and bitwise-xor bitwise-not bitwise-bit-set? bitwise-bit-field arithmetic-shift integer-length random random-seed make-pseudo-random-generator pseudo-random-generator? current-pseudo-random-generator pseudo-random-generator->vector vector->pseudo-random-generator vector->pseudo-random-generator! pseudo-random-generator-vector? number->string string->number real->decimal-string integer-bytes->integer integer->integer-bytes floating-point-bytes->real real->floating-point-bytes system-big-endian? pi pi.f degrees->radians radians->degrees sqr sgn conjugate sinh cosh tanh exact-round exact-floor exact-ceiling exact-truncate order-of-magnitude nan? infinite?))))
 
 
 @title[#:tag "sec:bools+ints+reals"]{Booleans, Integers, and Reals}
@@ -28,7 +27,6 @@ Rosette lifts the following operations on booleans, integers, and reals:
 (list (list @elem{Booleans} @bools)
       (list @elem{Integers and Reals} @nums))]
 
-
 Lifted boolean operations retain their Racket semantics on both concrete and symbolic values. 
 In particular, Rosette extends the intepretation of these operations to work on symbolic values in (logically) the 
 same way that they work on concrete values.
@@ -39,7 +37,7 @@ same way that they work on concrete values.
 (boolean? #t)
 (boolean? #f)
 (boolean? 1)
-(code:line (not b) (code:comment "produces a logical negation of b"))]
+(code:line (not b) (code:comment "Produces a logical negation of b."))]
 
 Lifted numeric operations, in contrast, match their Racket semantics
 only when applied to concrete values.  Their symbolic semantics depends on the
@@ -63,7 +61,7 @@ logical meaning; e.g., unlike Racket's shortcircuiting
 evaluates all of its arguments before taking their
 conjunction.
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(! [v boolean?]) boolean?]{
   Returns the negation of the given boolean value.
@@ -71,11 +69,11 @@ conjunction.
    (! #f)
    (! #t)
    (define-symbolic b boolean?)
-   (code:line (! (if b #f 3)) (code:comment "this typechecks only when b is true"))
-   (code:line (asserts)       (code:comment "so Rosette emits a corresponding assertion"))]
+   (code:line (! (if b #f 3)) (code:comment "This typechecks only when b is true,"))
+   (code:line (vc)            (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(&& [v boolean?] ...) boolean?]
            [(|| [v boolean?] ...) boolean?])]{
@@ -83,22 +81,22 @@ Returns the logical conjunction or disjunction of zero or more boolean values.
  @examples[#:eval rosette-eval
  (&&)
  (||)
- (code:line (&& #f (begin (displayln "hello") #t)) (code:comment "no shortcircuiting"))
+ (code:line (&& #f (begin (displayln "hello") #t)) (code:comment "No shortcircuiting."))
  (define-symbolic a b boolean?)
- (code:line (&& a (if b #t 1)) (code:comment "this typechecks only when b is true"))
- (code:line (asserts)          (code:comment "so Rosette emits a corresponding assertion"))]
+ (code:line (&& a (if b #t 1)) (code:comment "This typechecks only when b is true,"))
+ (code:line (vc)               (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc*[([(=>  [x boolean?] [y boolean?]) boolean?]
            [(<=> [x boolean?] [y boolean?]) boolean?])]{
 Returns the logical implication or bi-implication of two boolean values.
  @examples[#:eval rosette-eval
- (code:line (=> #f (begin (displayln "hello") #f)) (code:comment "no shortcircuiting"))
+ (code:line (=> #f (begin (displayln "hello") #f)) (code:comment "No shortcircuiting."))
  (define-symbolic a b boolean?)
- (code:line (<=> a (if b #t 1)) (code:comment "this typechecks only when b is true"))
- (code:line (asserts)           (code:comment "so Rosette emits a corresponding assertion"))]
+ (code:line (<=> a (if b #t 1)) (code:comment "This typechecks only when b is true,"))
+ (code:line (vc)                (code:comment "so Rosette emits a corresponding assertion."))]
 }
 
 @section[#:tag "sec:quantifiers"]{Quantifiers}
@@ -111,7 +109,7 @@ body may have side effects (e.g., generate assertions). When
 there are no side effects, however, these constructs have
 their usual logical meaning.
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @(rosette-eval '(current-bitwidth #f))
 @defproc*[([(forall [vs (listof constant?)] [body boolean?]) boolean?]
            [(exists [vs (listof constant?)] [body boolean?]) boolean?])]{
@@ -121,27 +119,32 @@ symbolic constants @racket[vs] are treated as quantified variables.
 Each constant in @racket[vs] must have a non-@racket[function?] @racket[solvable?] type.
 The @racket[body] argument is a boolean value, which is usually a symbolic 
 boolean expression over the quantified variables @racket[vs] and,
-optionally, over free symbolic (Skolem) constants. Any assertions emitted during
-the evaluation of @racket[body] are @emph{added to the assertion store}. This
-may be the desired behavior in some circumstances but not in others, so to avoid
-surprises, it is best to handle these assertions separately and call quantifiers
+optionally, over free symbolic (Skolem) constants. Any assertions and assumptions emitted during
+the evaluation of @racket[body] are added to the current verification condition @racket[(vc)].
+This may be the desired behavior in some circumstances but not in others, so to avoid
+surprises, it is best to handle side effects separately and call quantifiers
 with pure bodies, as shown below.
 
 @examples[#:eval rosette-eval
  (current-bitwidth #f)
  (define-symbolic x y integer?)
- (code:line (exists (list x y) (= x y)) (code:comment "pure body expression"))
- (define-symbolic t boolean?)
- (code:line (forall (list t x y) (= (+ (if t x 'x) 1) y)) (code:comment "body emits a type assertion"))
- (asserts)
- (clear-asserts!)
- (code:comment "To avoid surprises, capture assertions using with-asserts,")
+ (code:line
+  (exists (list x y) (= x y))   (code:comment "Pure body expression."))
+ (define-symbolic b boolean?)
+ (code:line
+  (forall (list b x y)
+    (= (+ (if b x 'x) 1) y))    (code:comment "Body emits a type assertion."))
+ (vc)
+ (clear-vc!)
+ (code:comment "To avoid surprises, capture assertions and assumptions using with-vc,")
  (code:comment "and handle as desired, e.g.:")
- (define-values (q-body q-asserts) (with-asserts (= (+ (if t x 'x) 1) y)))
- q-body
- q-asserts
- (forall (list t x y) (=> (apply && q-asserts) q-body))
- (asserts)
+ (define out (with-vc (= (+ (if b x 'x) 1) y)))
+ out
+ (define out-val (result-value out))
+ (define out-vc  (result-state out))
+ (forall (list b x y)
+   (=> (&& (vc-assumes out-vc) (vc-asserts out-vc)) out-val))
+ (vc)
 ] 
 
 The usual lexical scoping rules apply to quantified symbolics; if @racket[body] is
@@ -151,19 +154,33 @@ Quantified symbolics are not bound in a @racket[model], unless they also appear
 freely in some formulas. 
 
 @examples[#:eval rosette-eval
- (define-symbolic a b integer?)
- (code:line (define f (forall (list a) (exists (list b) (= a (+ a b))))) (code:comment "a and b are not free in f,"))
- (code:line (solve (assert f))                                           (code:comment "so not bound in the model."))
- (code:line (define g (forall (list a) (= a (+ a b))))                   (code:comment "b is free in g,")) 
- (code:line (solve (assert g))                                           (code:comment "so it is bound in the model."))
- (code:line (define h (exists (list a) (forall (list a) (= a (+ a a))))) (code:comment "body refers to the innermost a,"))
- (code:line (solve (assert h))                                           (code:comment "so h is unsatisfiable."))
+ (define-symbolic x y integer?)
+ (code:line
+  (define f                    
+   (forall (list x)
+     (exists (list y)
+       (= x (+ x y)))))        (code:comment "x and y are not free in f,"))
+ (code:line
+  (solve (assert f))           (code:comment "so they are not bound in the model."))
+ (code:line
+  (define g
+    (forall (list x)
+     (= x (+ x y))))           (code:comment "y is free in g,")) 
+ (code:line
+  (solve (assert g))           (code:comment "so it is bound in the model."))
+ (code:line
+  (define h
+    (exists (list x)
+      (forall (list x)
+        (= x (+ x x)))))       (code:comment "The body of h refers to the innermost x,"))
+ (code:line
+  (solve (assert h))           (code:comment "so h is unsatisfiable."))
 ]
 
 When executing queries over assertions that contain quantified formulas,
 the @racket[current-bitwidth] parameter must be set to @racket[#f].
-Quantified formulas may not appear in any assertion that is passed to a @racket[synthesize] query,
-either via an (implicit or explicit) assumption or a guarantee expression.
+Quantified formulas may not appear in any assertion or assumption that is passed
+to a @racket[synthesize] query.
 }
 
 

rosette/guide/scribble/datatypes/bools-log.txt

@@ -13,15 +13,15 @@
   0
   ()
   ()
-  (c values c (0 (u . "(! b)"))))
+  (c values c (0 (u . "(! b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((! #f) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((! #t) ((3) 0 () 0 () () (q values #f)) #"" #"")
 ((define-symbolic b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((! (if b #f 3)) ((3) 0 () 0 () () (q values #t)) #"" #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -30,15 +30,15 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "b")))))
+  (c values c (0 (u . "(vc #t b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((&&) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((||) ((3) 0 () 0 () () (q values #f)) #"" #"")
 ((&& #f (begin (displayln "hello") #t))
  ((3) 0 () 0 () () (q values #f))
- #""
+ #"hello\n"
  #"")
 ((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((&& a (if b #t 1))
@@ -50,10 +50,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "a"))))
+  (c values c (0 (u . "a\n"))))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -62,13 +62,13 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "b")))))
+  (c values c (0 (u . "(vc #t b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((=> #f (begin (displayln "hello") #f))
  ((3) 0 () 0 () () (q values #t))
- #""
+ #"hello\n"
  #"")
 ((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((<=> a (if b #t 1))
@@ -80,10 +80,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "a"))))
+  (c values c (0 (u . "a\n"))))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -92,10 +92,10 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "b")))))
+  (c values c (0 (u . "(vc #t b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((current-bitwidth #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((current-bitwidth #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -108,11 +108,11 @@
   0
   ()
   ()
-  (c values c (0 (u . "(exists (x y) (= x y))"))))
+  (c values c (0 (u . "(exists (x y) (= x y))\n"))))
  #""
  #"")
-((define-symbolic t boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((forall (list t x y) (= (+ (if t x 'x) 1) y))
+((define-symbolic b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((forall (list b x y) (= (+ (if b x 'x) 1) y))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -121,10 +121,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "(forall (t x y) (= y (+ 1 x)))"))))
+  (c values c (0 (u . "(forall (b x y) (= y (+ 1 x)))\n"))))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -133,15 +133,15 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "t")))))
+  (c values c (0 (u . "(vc #t b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-values (q-body q-asserts) (with-asserts (= (+ (if t x 'x) 1) y)))
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define out (with-vc (= (+ (if b x 'x) 1) y)))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-(q-body
+(out
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -150,10 +150,20 @@
   0
   ()
   ()
-  (c values c (0 (u . "(= y (+ 1 x))"))))
+  (c values c (0 (u . "(normal (= y (+ 1 x)) (vc #t b))\n"))))
  #""
  #"")
-(q-asserts
+((define out-val (result-value out))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define out-vc (result-state out))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((forall
+  (list b x y)
+  (=> (&& (vc-assumes out-vc) (vc-asserts out-vc)) out-val))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -162,10 +172,10 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "t")))))
+  (c values c (0 (u . "(forall (b x y) (|| (! b) (= y (+ 1 x))))\n"))))
  #""
  #"")
-((forall (list t x y) (=> (apply && q-asserts) q-body))
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -174,12 +184,11 @@
   0
   ()
   ()
-  (c values c (0 (u . "(forall (t x y) (|| (! t) (= y (+ 1 x))))"))))
+  (c values c (0 (u . "(vc #t #t)\n"))))
  #""
  #"")
-((asserts) ((3) 0 () 0 () () (q values ())) #"" #"")
-((define-symbolic a b integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define f (forall (list a) (exists (list b) (= a (+ a b)))))
+((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define f (forall (list x) (exists (list y) (= x (+ x y)))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
@@ -192,10 +201,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model)"))))
+  (c values c (0 (u . "(model)\n"))))
  #""
  #"")
-((define g (forall (list a) (= a (+ a b))))
+((define g (forall (list x) (= x (+ x y))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
@@ -208,10 +217,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [b 0])"))))
+  (c values c (0 (u . "(model\n [y 0])\n"))))
  #""
  #"")
-((define h (exists (list a) (forall (list a) (= a (+ a a)))))
+((define h (exists (list x) (forall (list x) (= x (+ x x)))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
@@ -224,6 +233,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")

rosette/guide/scribble/datatypes/boxes-log.txt

@@ -15,6 +15,40 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate v1 sol) ((3) 0 () 0 () () (c values c (b! . 4))) #"" #"")
-((evaluate v2 sol) ((3) 0 () 0 () () (c values c (b! . 4))) #"" #"")
+(sol
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [x 4]\n [b #t])\n"))))
+ #""
+ #"")
+((evaluate v1 sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#&4\n"))))
+ #""
+ #"")
+((evaluate v2 sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#&4\n"))))
+ #""
+ #"")
 ((evaluate (eq? v1 v2) sol) ((3) 0 () 0 () () (q values #t)) #"" #"")

rosette/guide/scribble/datatypes/boxes.scrbl

@@ -1,7 +1,8 @@
 #lang scribble/manual
 
-@(require (for-label rosette/base/form/define racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+@(require (for-label rosette/base/form/define rosette/query/query racket
+                     (only-in rosette/base/base assert))
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 @(define box-ops (select '(box? box box-immutable unbox set-box! box-cas!)))
@@ -30,9 +31,10 @@ they point to the same box object.  Boxes can be concrete or symbolic, and they
 @examples[#:eval rosette-eval
 (define-symbolic x integer?)
 (define-symbolic b boolean?)
-(code:line (define v1 (box x))           (code:comment "v1 is a box with symbolic contents"))
-(code:line (define v2 (if b v1 (box 3))) (code:comment "v2 is a symbolic box"))
+(code:line (define v1 (box x))           (code:comment "v1 is a box with symbolic contents."))
+(code:line (define v2 (if b v1 (box 3))) (code:comment "v2 is a symbolic box."))
 (define sol (solve (assert (= 4 (unbox v2)))))
+sol
 (evaluate v1 sol)
 (evaluate v2 sol)
 (evaluate (eq? v1 v2) sol)]

rosette/guide/scribble/datatypes/defined-datatypes-log.txt

@@ -25,7 +25,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(ite b 1 3)"))))
+  (c values c (0 (u . "(ite b 1 3)\n"))))
  #""
  #"")
 ((point-y p)
@@ -37,7 +37,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(ite b 2 4)"))))
+  (c values c (0 (u . "(ite b 2 4)\n"))))
  #""
  #"")
 ((define sol (solve (assert (= (point-x p) 3))))
@@ -53,7 +53,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "#(struct:point 3 4)"))))
+  (c values c (0 (u . "(point 3 4)\n"))))
  #""
  #"")
 ((define-generics viewable (view viewable))
@@ -93,7 +93,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(ite b 2 3)"))))
+  (c values c (0 (u . "(ite b 2 3)\n"))))
  #""
  #"")
 ((define sol (solve (assert (= (view p) 3))))
@@ -109,6 +109,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "#(struct:circle 3)"))))
+  (c values c (0 (u . "(circle 3)\n"))))
  #""
  #"")

rosette/guide/scribble/datatypes/defined-datatypes.scrbl

@@ -1,10 +1,10 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/query/query rosette/query/eval  
-           rosette/base/core/term (only-in rosette/base/core/safe assert) 
+           rosette/base/form/define rosette/query/query  
+           rosette/base/core/term (only-in rosette/base/base assert) 
            racket racket/generic)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 @(define-runtime-path root ".")
@@ -27,10 +27,10 @@ Structure types are defined  using the @racket[struct] syntax. Defining a
 structure type in this way also defines the necessary procedures for
 creating instances of that type and for accessing their fields. 
 
-@interaction[#:eval rosette-eval
-(struct point (x y) #:transparent)         (code:comment "immutable transparent type")
-(struct pt (x y))                          (code:comment "opaque immutable type")
-(struct pnt (x y) #:mutable #:transparent) (code:comment "mutable transparent type")]
+@examples[#:eval rosette-eval #:label #f
+(struct point (x y) #:transparent)         (code:comment "Immutable transparent type.")
+(struct pt (x y))                          (code:comment "Opaque immutable type.")
+(struct pnt (x y) #:mutable #:transparent) (code:comment "Mutable transparent type.")]
 
 Rosette structures can be concrete or symbolic.  Their semantics matches that of Racket, 
 with one important exception:  immutable transparent structures are treated as values 
@@ -39,10 +39,10 @@ rather than references.  This @seclink["sec:equality"]{means} that two such stru
 Structures of opaque or mutable types are treated as references.  Two such structures are
 @racket[eq?] only if the point to the same instance of the same type.
 
-@interaction[#:eval rosette-eval
-(code:line (eq? (point 1 2) (point 1 2))  (code:comment "point structures are values"))
-(code:line (eq? (pt 1 2) (pt 1 2))        (code:comment "pt structures are references"))
-(code:line (eq? (pnt 1 2) (pnt 1 2))      (code:comment "pnt structures are references"))]
+@examples[#:eval rosette-eval #:label #f
+(code:line (eq? (point 1 2) (point 1 2))  (code:comment "point structures are values."))
+(code:line (eq? (pt 1 2) (pt 1 2))        (code:comment "pt structures are references."))
+(code:line (eq? (pnt 1 2) (pnt 1 2))      (code:comment "pnt structures are references."))]
 
 Like @tech[#:key "unsolvable type"]{unsolvable built-in datatypes}, 
 symbolic structures cannot be created using @racket[define-symbolic].  Instead, 
@@ -50,9 +50,9 @@ they are created implicitly, by, for example, using an @racket[if] expression
 together with a symbolic value.
 
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define-symbolic b boolean?)
-(code:line (define p (if b (point 1 2) (point 3 4))) (code:comment "p holds a symbolic structure"))
+(code:line (define p (if b (point 1 2) (point 3 4))) (code:comment "p holds a symbolic structure."))
 (point-x p)
 (point-y p)
 (define sol (solve (assert (= (point-x p) 3))))
@@ -67,7 +67,8 @@ properties, generic interfaces, and facilities for defining new properties and i
       (list @elem{Lifted Generics} @elem{@generics} ))]
 
 Lifted generics work as expected with symbolic values:
-@interaction[#:eval rosette-eval
+
+@examples[#:eval rosette-eval #:label #f
 (define-generics viewable (view viewable))
 
 (struct square (side) 
@@ -80,7 +81,7 @@ Lifted generics work as expected with symbolic values:
   [(define (view self) (circle-radius self))])
 
 (define-symbolic b boolean?)
-(code:line (define p (if b (square 2) (circle 3))) (code:comment "p holds a symbolic structure"))
+(code:line (define p (if b (square 2) (circle 3))) (code:comment "p holds a symbolic structure."))
 (view p)
 (define sol (solve (assert (= (view p) 3))))
 (evaluate p sol)]

rosette/guide/scribble/datatypes/equality.scrbl

@@ -2,7 +2,7 @@
 
 @(require (for-label rosette/base/form/define racket)
           (for-label (only-in rosette/base/base function? distinct? ~> bv))
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+          scribble/core scribble/html-properties scribble/examples racket/sandbox
           "../util/lifted.rkt")
 
 
@@ -27,7 +27,7 @@ notion of @racket[equal?] is specified for a particular datatype.
 (equal? n 1)
 (equal? (box n) (box 1))
 (define-symbolic f g (~> integer? integer?))
-(code:line (equal? f g)             (code:comment "f and g are different procedures"))]
+(code:line (equal? f g)             (code:comment "f and g are different procedures."))]
 @(kill-evaluator rosette-eval)
 @(set! rosette-eval (rosette-evaluator))
 
@@ -43,25 +43,25 @@ or two transparent immutable values with @racket[eq?] contents.
 
 @examples[#:eval rosette-eval
 (eq? 1 #t)
-(code:line (eq? 1 1.0)                (code:comment "equal? transparent solvable values"))
-(code:line (eq? (list 1) (list 1.0))  (code:comment "transparent immutable values with eq? contents"))
-(code:line (eq? (box 1) (box 1))      (code:comment "but boxes are mutable, so eq? follows Racket"))
+(code:line (eq? 1 1.0)                (code:comment "equal? transparent solvable values."))
+(code:line (eq? (list 1) (list 1.0))  (code:comment "Transparent immutable values with eq? contents."))
+(code:line (eq? (box 1) (box 1))      (code:comment "But boxes are mutable, so eq? follows Racket,"))
 (eq? (list (box 1)) (list (box 1)))
 (define-symbolic n integer?)
 (eq? n 1)
 (eq? (box n) (box 1))
 (define-symbolic f g (~> integer? integer?))
-(code:line (eq? f g)                  (code:comment "and procedures are opaque, so eq? follows Racket"))
+(code:line (eq? f g)                  (code:comment "and procedures are opaque, so eq? follows Racket."))
 (eq? f f)]
 
 In addition to lifting Racket's equality predicates, Rosette also provides a @racket[distinct?] predicate
 that returns true iff all of its arguments are distinct from each other.  Invoking this predicate
-on arbitrary values has the effect of performing O(@var[N]@superscript{2}) @racket[not] @racket[equal?]
+on arbitrary values has the effect of performing O(@var[N]@superscript{2}) equality 
 comparisons.  But when applied to symbolic values of a primitive 
 @tech[#:key "solvable type"]{solvable} type, @racket[distinct?] will produce a compact
 symbolic value that can be directly solved by the underlying solver.
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @defproc[(distinct? [v any/c] ...) boolean?]{
   Returns true iff all of the given values @racket[v] are distinct---i.e., pairwise un-@racket[equal?]
   to each other.  If all values @racket[v] are of the same primitive (non-@racket[function?])

rosette/guide/scribble/datatypes/pairs-log.txt

@@ -11,7 +11,18 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate xs sol) ((3) 0 () 0 () () (q values ())) #"" #"")
+((evaluate xs sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'()\n"))))
+ #""
+ #"")
 ((define sol
    (solve
     (begin
@@ -21,7 +32,18 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate xs sol) ((3) 0 () 0 () () (q values (-1 0))) #"" #"")
+((evaluate xs sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(-1 0)\n"))))
+ #""
+ #"")
 ((define-symbolic b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define p (if b (cons 1 2) (cons 4 #f)))
  ((3) 0 () 0 () () (c values c (void)))
@@ -31,9 +53,31 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate p sol) ((3) 0 () 0 () () (q values (4 . #f))) #"" #"")
+((evaluate p sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(4 . #f)\n"))))
+ #""
+ #"")
 ((define sol (solve (assert (odd? (car p)))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate p sol) ((3) 0 () 0 () () (q values (1 . 2))) #"" #"")
+((evaluate p sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(1 . 2)\n"))))
+ #""
+ #"")

rosette/guide/scribble/datatypes/pairs.scrbl

@@ -3,9 +3,15 @@
 @(require (for-label 
            rosette/base/form/define rosette/query/query  
            rosette/base/core/term  
-           (only-in rosette/base/core/safe assert) 
+           (only-in rosette/base/base assert vc clear-vc! define-symbolic
+                    length-bv list-ref-bv list-set-bv
+                    take-bv take-right-bv
+                    drop-bv drop-right-bv
+                    list-tail-bv split-at-bv split-at-right-bv
+                    union? bitvector bitvector? bv?
+                    bitvector->natural integer->bitvector) 
            racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 
@@ -18,7 +24,7 @@
 @(define list-filtering (select '(filter remove remq remv remove* remq* remv* sort)))
 @(define list-searching (select '(member memv memq memf findf assoc assv assq assf)))
 @(define more-pair-ops (select '(caar cadr cdar cddr caaar caadr cadar caddr cdaar cdadr cddar cdddr caaaar caaadr caadar caaddr cadaar cadadr caddar cadddr cdaaar cdaadr cdadar cdaddr cddaar cddadr cdddar cddddr)))
-@(define more-list-ops (select '(empty cons? empty? first rest second third fourth fifth sixth seventh eighth ninth tenth last last-pair make-list take drop split-at takef dropf splitf-at take-right drop-right split-at-right takef-right dropf-right splitf-at-right add-between append* flatten remove-duplicates filter-map count partition range append-map filter-not shuffle permutations in-permutations argmin argmax )))
+@(define more-list-ops (select '(empty cons? empty? first rest second third fourth fifth sixth seventh eighth ninth tenth last last-pair make-list take drop split-at takef dropf splitf-at take-right drop-right split-at-right takef-right dropf-right splitf-at-right add-between append* flatten remove-duplicates filter-map count partition range append-map filter-not shuffle permutations in-permutations argmin argmax list-set)))
 
 @title[#:tag "sec:pair"]{Pairs and Lists}
 
@@ -34,10 +40,11 @@ and lists cannot be created
 via @seclink["sec:symbolic-constants"]{@code{define-symbolic[*]}}. 
 Instead, they are created by applying pair- or list-producing procedures to symbolic inputs, 
 or by controlling the application of such procedures with symbolic values.  This   
- pattern for creating non-primitive symbolic values generalizes to all unsolvable datatypes.
+pattern for creating non-primitive symbolic values generalizes to all unsolvable datatypes.
+
 @examples[#:eval rosette-eval
 (define-symbolic x y z n integer?)
-(code:line (define xs (take (list x y z) n))        (code:comment "(1) xs is a symbolic list"))
+(code:line (define xs (take (list x y z) n))        (code:comment "(1) xs is a symbolic list."))
 (define sol (solve (assert (null? xs))))
 (evaluate xs sol)
 (define sol 
@@ -49,13 +56,15 @@ or by controlling the application of such procedures with symbolic values.  This
 
 @examples[#:eval rosette-eval
 (define-symbolic b boolean?)
-(code:line (define p (if b (cons 1 2) (cons 4 #f))) (code:comment "(2) p is a symbolic pair"))
+(code:line (define p (if b (cons 1 2) (cons 4 #f))) (code:comment "(2) p is a symbolic pair."))
 (define sol (solve (assert (boolean? (cdr p)))))
 (evaluate p sol)
 (define sol (solve (assert (odd? (car p)))))
 (evaluate p sol)
 ]
 
+@section{Lifted Operations on Pairs and Lists}
+
 Rosette lifts the following operations on pairs and lists:
 @tabular[#:style (style #f (list (attributes '((id . "lifted")(class . "boxed")))))
 (list (list @elem{Pair Operations} @pairs:constructors+selectors)
@@ -67,3 +76,118 @@ Rosette lifts the following operations on pairs and lists:
       (list @elem{Additional List Operations} @more-list-ops))]
 
 @(kill-evaluator rosette-eval)
+@(set! rosette-eval (rosette-evaluator))
+
+@section{Additional Operations on Pairs and Lists}
+
+Rosette provides the following procedures for operating on lists using @seclink["sec:bitvectors"]{bitvector} indices and lengths. These procedures produce symbolic values that avoid @racketlink[bitvector->natural]{casting} their bitvector arguments to integers, leading to @seclink["sec:notes"]{more efficiently solvable queries}. 
+
+@declare-exporting[rosette/base/base #:use-sources (rosette/base/base)]
+
+@defproc[(length-bv [lst list?] [t (or/c bitvector? union?)]) bv?]{
+Equivalent to @racket[(integer->bitvector (length lst) t)] but avoids the @racket[integer->bitvector] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic b boolean?)
+(define xs (if b '(1 2) '(3 4 5 6)))
+xs
+(integer->bitvector (length xs) (bitvector 4))
+(length-bv xs (bitvector 4))]
+}
+
+@defproc[(list-ref-bv [lst list?] [pos bv?]) any/c]{
+Equivalent to @racket[(list-ref lst (bitvector->natural pos))] but avoids the @racket[bitvector->natural] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs '(1 2 3 4))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(list-ref xs (bitvector->natural p))
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(list-ref-bv xs p)
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(list-ref-bv xs q)
+(vc)]
+              
+}
+
+@(rosette-eval '(clear-vc!))
+@defproc[(list-set-bv [lst list?] [pos bv?] [val any/c]) list?]{
+Equivalent to @racket[(list-set lst (bitvector->natural pos) val)] but avoids the @racket[bitvector->natural] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs '(1 2 3 4))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(list-set xs (bitvector->natural p) 5)
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(list-set-bv xs p 5)
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(list-set-bv xs q 5)
+(vc)]              
+}
+
+@(rosette-eval '(clear-vc!))
+@defproc*[([(take-bv [lst any/c] [pos bv?]) list?]
+           [(take-right-bv [lst any/c] [pos bv?]) any/c]
+           [(drop-bv [lst any/c] [pos bv?]) any/c]
+           [(drop-right-bv [lst any/c] [pos bv?]) list?]
+           [(list-tail-bv [lst any/c] [pos bv?]) any/c])]{
+                                                          
+ Equivalent to @racket[take], @racket[take-right],
+ @racket[drop], @racket[drop-right], or @racket[list-tail]
+ applied to @racket[lst] and
+ @racket[(bitvector->natural pos)], but avoids the
+ @racket[bitvector->natural] cast for better solving
+ performance.
+
+ @examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs (cons 1 (cons 2 (cons 3 4))))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(take xs (bitvector->natural p))
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(take-bv xs p)
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(take-bv xs q)
+(vc)]              
+}
+
+@(rosette-eval '(clear-vc!))
+@defproc*[([(split-at-bv [lst any/c] [pos bv?]) (list? any/c)]
+           [(split-at-right-bv [lst any/c] [pos bv?]) (list? any/c)])]{
+
+ Equivalent to
+ @racket[(split-at lst (bitvector->natural pos))] or
+ @racket[(split-at-right lst (bitvector->natural pos))], but
+ avoids the @racket[bitvector->natural] cast for better
+ solving performance.
+
+ @examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs (cons 1 2))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(split-at xs (bitvector->natural p))
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(split-at-bv xs p)
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(split-at-bv xs q)
+(vc)]}
+
+@(kill-evaluator rosette-eval)

rosette/guide/scribble/datatypes/procedures-log.txt

@@ -19,7 +19,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "*"))))
+  (c values c (0 (u . "*\n"))))
  #""
  #"")
 ((define sol (synthesize #:forall (list x) #:guarantee (assert (= x (p x 0)))))
@@ -35,6 +35,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "-"))))
+  (c values c (0 (u . "-\n"))))
  #""
  #"")

rosette/guide/scribble/datatypes/procedures.scrbl

@@ -1,11 +1,11 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/query/query rosette/query/eval  
+           rosette/base/form/define rosette/query/query 
            rosette/base/core/term  
-           (only-in rosette/base/core/safe assert) 
+           (only-in rosette/base/base assert) 
            racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 
@@ -27,7 +27,7 @@ which any symbolic procedure could @racket[evaluate] under any @racket[solution?
 @examples[#:eval rosette-eval
 (define-symbolic b boolean?)
 (define-symbolic x integer?)
-(code:line (define p (if b * -)) (code:comment "p is a symbolic procedure"))
+(code:line (define p (if b * -)) (code:comment "p is a symbolic procedure."))
 (define sol (synthesize #:forall (list x)
                         #:guarantee (assert (= x (p x 1)))))
 (evaluate p sol)

rosette/guide/scribble/datatypes/solvers+solutions.scrbl

@@ -2,13 +2,17 @@
 
 @(require (for-label 
            rosette/solver/solver rosette/solver/solution 
-           (only-in rosette/query/debug debug)
-           rosette/solver/smt/z3 rosette/solver/smt/cvc4 rosette/solver/smt/boolector rosette/solver/smt/yices rosette/solver/mip/cplex
-           rosette/base/form/define rosette/query/query rosette/query/core
+           rosette/solver/smt/z3 rosette/solver/smt/cvc4
+           rosette/solver/smt/boolector 
+           rosette/solver/smt/bitwuzla
+           rosette/solver/smt/cvc5
+           rosette/solver/smt/stp
+           rosette/solver/smt/yices
+           rosette/base/form/define rosette/query/query 
            rosette/base/core/term (only-in rosette/base/base bv?)
-           (only-in rosette/base/core/safe assert) 
+           (only-in rosette/base/base assert) 
            racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 @(define-runtime-path root ".")
@@ -16,31 +20,34 @@
 
 @title[#:tag "sec:solvers-and-solutions"]{Solvers and Solutions}
 
-@declare-exporting[rosette/query/core
-                   rosette/query/eval
+@declare-exporting[rosette/query/query
                    rosette/solver/solver
                    rosette/solver/solution
                    rosette/solver/smt/z3
-                   rosette/solver/mip/cplex
                    rosette/solver/smt/cvc4
-                   rosette/solver/smt/yices
                    rosette/solver/smt/boolector
+                   rosette/solver/smt/bitwuzla
+                   rosette/solver/smt/cvc5
+                   rosette/solver/smt/stp
+                   rosette/solver/smt/yices
                    #:use-sources 
                    (rosette/query/finitize
-                    rosette/query/eval
+                    rosette/query/query
                     rosette/solver/solver
                     rosette/solver/solution
                     rosette/solver/smt/z3
-                    rosette/solver/mip/cplex
                     rosette/solver/smt/cvc4
-                    rosette/solver/smt/yices
-                    rosette/solver/smt/boolector)]
+                    rosette/solver/smt/boolector
+                    rosette/solver/smt/bitwuzla
+                    rosette/solver/smt/cvc5
+                    rosette/solver/smt/stp
+                    rosette/solver/smt/yices)]
 
 A @deftech{solver} is an automatic reasoning engine, used to answer 
 @seclink["sec:queries"]{queries} about Rosette programs.  The result of
 a solver invocation is a @deftech{solution}, containing either 
 a @tech{binding} of symbolic constants to concrete values, or 
-an @tech[#:key "MUC"]{unsatisfiable core}. 
+an @link["https://en.wikipedia.org/wiki/Unsatisfiable_core"]{unsatisfiable core}. 
 Solvers and solutions may not be symbolic.  Two solvers (resp. solutions) are @racket[eq?]/@racket[equal?] 
 if they refer to the same object.
 
@@ -189,7 +196,7 @@ Returns the options the given solver is configured with
 
 @section{Supported Solvers}
 
-Rosette supports several SMT solvers as well as the CPLEX mixed-integer programming solver.
+Rosette supports several SMT solvers.
 The @racket[current-solver] parameter controls the solver used for answering solver-aided queries.
 Each supported solver is contained in a separate module
 (e.g., @racketmodname[rosette/solver/smt/z3]),
@@ -204,6 +211,7 @@ to create a new solver instance.
                 [#:logic logic (or/c symbol? #f) #f]
                 [#:options options (hash/c symbol? any/c) (hash)]) solver?]
            [(z3? [v any/c]) boolean?])]{
+                                        
 Returns a @racket[solver?] wrapper for the @hyperlink["https://github.com/Z3Prover/z3/"]{Z3} solver from Microsoft Research.
 Rosette automatically installs a version of Z3;
 the optional @racket[path] argument overrides this version with a path to a new Z3 binary.
@@ -228,9 +236,10 @@ will send the command @tt{(set-option :smt.relevancy 0)} to Z3 prior to solving.
                   [#:logic logic (or/c symbol? #f) #f]
                   [#:options options (hash/c symbol? any/c) (hash)]) solver?]
            [(cvc4? [v any/c]) boolean?])]{
+                                          
 Returns a @racket[solver?] wrapper for the @hyperlink["http://cvc4.cs.stanford.edu/web/"]{CVC4} solver from NYU and UIowa.
 
-To use this solver, download and install CVC4,
+To use this solver, download and install CVC4 (version 1.8 or later),
 and either add the @tt{cvc4} executable to your @tt{PATH}
 or pass the path to the executable as the optional @racket[path] argument.
 
@@ -259,6 +268,7 @@ without its optional @racket[path] argument.}
                        [#:logic logic (or/c symbol? #f) #f]
                        [#:options options (hash/c symbol? any/c) (hash)]) solver?]
            [(boolector? [v any/c]) boolean?])]{
+                                               
 Returns a @racket[solver?] wrapper for the @hyperlink["http://fmv.jku.at/boolector/"]{Boolector} solver from JKU.
 
 To use this solver, download and install Boolector (version 2.4.1 or later),
@@ -281,81 +291,146 @@ Returns true if the Boolector solver is available for use (i.e., Rosette can loc
 If this returns @racket[#f], @racket[(boolector)] will not succeed
 without its optional @racket[path] argument.}
 
+@subsection{Bitwuzla}
 
-@subsection{Yices}
+@defmodule[rosette/solver/smt/bitwuzla #:no-declare]
+
+@defproc*[([(bitwuzla [#:path path (or/c path-string? #f) #f]
+                      [#:logic logic (or/c symbol? #f) #f]
+                      [#:options options (hash/c symbol? any/c) (hash)]) solver?]
+           [(bitwuzla? [v any/c]) boolean?])]{
+                                               
+Returns a @racket[solver?] wrapper for the @hyperlink["https://bitwuzla.github.io/"]{Bitwuzla} solver.
+
+To use this solver, download prebuilt Bitwuzla or build it yourself,
+and ensure the executable is on your @tt{PATH} or pass the path to the 
+executable as the optional @racket[path] argument.
+Rosette currently tests Bitwuzla at commit 
+@tt{93a3d930f622b4cef0063215e63b7c3bd10bd663}.
+
+The optional @racket[logic] argument specifies an SMT logic for the solver to use (e.g., @racket['QF_BV]).
+Specifying a logic can improve solving performance, but Rosette makes no effort to check that
+emitted constraints fall within the chosen logic. The default is @racket[#f],
+which uses Bitwuzla's default logic.
+
+The @racket[options] argument provides additional options that are sent to Bitwuzla
+via the @tt{set-option} SMT command.
+For example, setting @racket[options] to @racket[(hash ':seed 5)]
+will send the command @tt{(set-option :seed 5)} to Bitwuzla prior to solving.
+}
+
+@defproc[(bitwuzla-available?) boolean?]{
+Returns true if the Bitwuzla solver is available for use (i.e., Rosette can locate a @tt{bitwuzla} binary).
+If this returns @racket[#f], @racket[(bitwuzla)] will not succeed
+without its optional @racket[path] argument.}
+
+@subsection{CVC5}
+
+@defmodule[rosette/solver/smt/cvc5 #:no-declare]
+
+@defproc*[([(cvc5 [#:path path (or/c path-string? #f) #f]
+                  [#:logic logic (or/c symbol? #f) #f]
+                  [#:options options (hash/c symbol? any/c) (hash)]) solver?]
+           [(cvc5? [v any/c]) boolean?])]{
+                                               
+Returns a @racket[solver?] wrapper for the @hyperlink["https://cvc5.github.io/"]{CVC5} solver.
+
+To use this solver, download prebuilt CVC5 or build it yourself,
+and ensure the executable is on your @tt{PATH} or pass the path to the 
+executable as the optional @racket[path] argument.
+Rosette currently tests CVC5 at version 1.0.7.
+
+The optional @racket[logic] argument specifies an SMT logic for the solver to use (e.g., @racket['QF_BV]).
+Specifying a logic can improve solving performance, but Rosette makes no effort to check that
+emitted constraints fall within the chosen logic. The default is @racket[#f],
+which uses CVC5's default logic.
+
+The @racket[options] argument provides additional options that are sent to CVC5
+via the @tt{set-option} SMT command.
+For example, setting @racket[options] to @racket[(hash ':seed 5)]
+will send the command @tt{(set-option :seed 5)} to CVC5 prior to solving.
+}
+
+@defproc[(cvc5-available?) boolean?]{
+Returns true if the CVC5 solver is available for use (i.e., Rosette can locate a @tt{cvc5} binary).
+If this returns @racket[#f], @racket[(cvc5)] will not succeed
+without its optional @racket[path] argument.}
+
+@subsection{STP}
+
+@defmodule[rosette/solver/smt/stp #:no-declare]
+
+@defproc*[([(stp [#:path path (or/c path-string? #f) #f]
+                 [#:logic logic (or/c symbol? #f) #f]
+                 [#:options options (hash/c symbol? any/c) (hash)]) solver?]
+           [(stp? [v any/c]) boolean?])]{
+                                               
+Returns a @racket[solver?] wrapper for the @hyperlink["https://stp.github.io/"]{STP} solver.
+
+To use this solver, download prebuilt STP or build it yourself,
+and ensure the executable is on your @tt{PATH} or pass the path to the 
+executable as the optional @racket[path] argument.
+Rosette currently tests STP at commit 
+@tt{0510509a85b6823278211891cbb274022340fa5c}.
+Note that as of December 2023, the STP version on Mac Homebrew is too old to be
+supported by Rosette.
+
+The optional @racket[logic] argument specifies an SMT logic for the solver to use (e.g., @racket['QF_BV]).
+Specifying a logic can improve solving performance, but Rosette makes no effort to check that
+emitted constraints fall within the chosen logic. The default is @racket[#f],
+which uses STP's default logic.
+
+The @racket[options] argument provides additional options that are sent to STP
+via the @tt{set-option} SMT command.
+For example, setting @racket[options] to @racket[(hash ':seed 5)]
+will send the command @tt{(set-option :seed 5)} to STP prior to solving.
+}
+
+@defproc[(stp-available?) boolean?]{
+Returns true if the STP solver is available for use (i.e., Rosette can locate a @tt{stp} binary).
+If this returns @racket[#f], @racket[(stp)] will not succeed
+without its optional @racket[path] argument.}
+
+@subsection{Yices2}
 
 @defmodule[rosette/solver/smt/yices #:no-declare]
 
 @defproc*[([(yices [#:path path (or/c path-string? #f) #f]
-                   [#:logic logic symbol? 'ALL]
+                   [#:logic logic (or/c symbol? #f) 'QF_BV]
                    [#:options options (hash/c symbol? any/c) (hash)]) solver?]
            [(yices? [v any/c]) boolean?])]{
-Returns a @racket[solver?] wrapper for the @hyperlink["http://yices.csl.sri.com/"]{Yices} solver from SRI.
                                                
-To use this solver, download and install Yices (version 2.6.0 or later),
-and either add the @tt{yices-smt2} executable to your @tt{PATH}
-or pass the path to the executable as the optional @racket[path] argument.
+Returns a @racket[solver?] wrapper for the @hyperlink["https://yices.csl.sri.com/"]{Yices2} solver.
+
+To use this solver, download prebuilt Yices2 or build it yourself,
+and ensure the executable is on your @tt{PATH} or pass the path to the 
+executable as the optional @racket[path] argument.
+Rosette specifically uses the @tt{yices-smt2} executable, which is the Yices2
+solver with its SMTLIB2 frontend enabled.
+Note that just building (without installing) Yices2 will produce an executable
+named @tt{yices_smt2}. Running the installation step produces an executable
+with the correct name. However, it is safe to skip the installation step and
+simply rename or symlink the @tt{yices_smt2} executable to @tt{yices-smt2}.
+Rosette currently tests Yices2 at commit 
+@tt{e27cf308cffb0ecc6cc7165c10e81ca65bc303b3}.
 
 The optional @racket[logic] argument specifies an SMT logic for the solver to use (e.g., @racket['QF_BV]).
 Specifying a logic can improve solving performance, but Rosette makes no effort to check that
-emitted constraints fall within the chosen logic. The default is @racket['ALL].
+emitted constraints fall within the chosen logic. Yices2 expects a logic to be
+set; Rosette defaults to @racket['QF_BV].
 
-The @racket[options] argument provides additional options that are sent to Yices
+The @racket[options] argument provides additional options that are sent to Yices2
 via the @tt{set-option} SMT command.
-For example, setting @racket[options] to @racket[(hash ':random-seed 5)]
-will send the command @tt{(set-option :random-seed 5)} to Yices prior to solving.
+For example, setting @racket[options] to @racket[(hash ':seed 5)]
+will send the command @tt{(set-option :seed 5)} to Yices2 prior to solving.
 }
 
 @defproc[(yices-available?) boolean?]{
-Returns true if the Yices solver is available for use (i.e., Rosette can locate a @tt{yices-smt2} binary).
+Returns true if the Yices2 solver is available for use (i.e., Rosette can locate a @tt{yices-smt2} binary).
 If this returns @racket[#f], @racket[(yices)] will not succeed
 without its optional @racket[path] argument.}
 
 
-@subsection{CPLEX}
-
-@defmodule[rosette/solver/mip/cplex #:no-declare]
-
-@defproc*[([(cplex [#:path path (or/c path-string? #f) #f]
-                   [#:options options (hash/c symbol? any/c) (hash)]) solver?]
-           [(cplex? [v any/c]) boolean?])]{
-Returns a @racket[solver?] wrapper for the
-@hyperlink["https://www.ibm.com/developerworks/community/blogs/jfp/entry/CPLEX_Is_Free_For_Students?lang=en"]{CPLEX} solver from IBM.
-
-To use this solver, download and install CPLEX,
-and locate the CPLEX interactive executable,
-which is likely to be at @tt{CPLEX_Studio*/cplex/bin/x86-64*/cplex}.
-Either add this directory to your @tt{PATH},
-or pass the path to the executable as the @racket[path] argument.
-
-The @racket[options] argument provides additional options for configuring CPLEX.
-Setting the key @racket['timeout] in @racket[options] to an integer controls the solving timeout in seconds.
-Setting the key @racket['verbose] in @racket[options] to @racket[#t] displays detailed output from the CPLEX solver.
-
-The assertions given to @racket[solver-assert] must be linear in order to use the CPLEX solver. Otherwise, an @racket[exn:fail] exception is raised. 
-}
-
-@defproc[(cplex-available?) boolean?]{
-Returns true if the CPLEX solver is available for use (i.e., Rosette can locate a @tt{cplex} binary).
-If this returns @racket[#f], @racket[(cplex)] will not succeed
-without its optional @racket[path] argument.}
-
-@defproc[(solver-check-with-init 
-          [solver cplex?]
-          [#:mip-sol final-solution-file (or/c path-string? #f) #f]
-          [#:mip-start initial-solution-file (or/c path-string? #f) #f])
-         solution?]{
-Like @racket[solver-check], but accepts only a CPLEX solver,
-and takes optional arguments @racket[final-solution-file] and/or @racket[initial-solution-file].
-When @racket[final-solution-file] is a @racket[path-string?],
-the solver will save the solution to the given file in
-@hyperlink["https://www.ibm.com/support/knowledgecenter/bs/SSSA5P_12.6.2/ilog.odms.cplex.help/CPLEX/FileFormats/topics/MST.html"]{MST format}
-if a solution exists.
-This file can be used as the @racket[initial-solution-file] in a later call to @racket[solver-check-with-init]
-to provide starting values for variables.
-Note that @racket[initial-solution-file] does not have to be a satisfiable solution, but it must be in MST format.
-}
-
 @section{Solutions}
 
 A solution to a set of formulas may be satisfiable (@racket[sat?]), unsatisfiable  (@racket[unsat?]),
@@ -368,17 +443,17 @@ the given constraints are satisfiable or not.
 
 A solution supports the following operations:
 
-@defproc[(solution? [value any/c]) boolean?]{
-Returns true if the given @racket[value] is a solution.}
+@defproc[(solution? [v any/c]) boolean?]{
+Returns true if @racket[v] is a solution.}
 
-@defproc[(sat? [value any/c]) boolean?]{
-Returns true if the given @racket[value] is a satisfiable solution.}
+@defproc[(sat? [v any/c]) boolean?]{
+Returns true if @racket[v] is a satisfiable solution.}
 
-@defproc[(unsat? [value any/c]) boolean?]{
-Returns true if the given @racket[value] is an unsatisfiable solution.}
+@defproc[(unsat? [v any/c]) boolean?]{
+Returns true if @racket[v] is an unsatisfiable solution.}
 
-@defproc[(unknown? [value any/c]) boolean?]{
-Returns true if the given @racket[value] is an unknown solution.}
+@defproc[(unknown? [v any/c]) boolean?]{
+Returns true if @racket[v] is an unknown solution.}
 
 @defproc*[([(sat) sat?]
            [(sat [binding (hash/c constant? any/c #:immutable #t)]) sat?])]{
@@ -395,26 +470,27 @@ are provided, applying @racket[core] to the resulting solution produces @racket[
 indicating that there is no satisfying solution but
 core extraction was not performed.  (Core extraction is an expensive 
 operation that is not supported by all solvers; those that do support it 
-usually don't compute a core unless explicitly asked for one via @racket[solver-debug].)}
+do not compute a core unless explicitly asked for one via @racket[solver-debug].)}
 
 @defproc[(unknown) unknown?]{
 Returns an unknown solution.}
 
-@defproc[(model [solution sat?]) (hash/c constant? any/c #:immutable #t)]{
+@defproc[(model [sol sat?]) (hash/c constant? any/c #:immutable #t)]{
 Returns the binding stored in the given satisfiable solution.  The binding is an immutable
 hashmap from symbolic constants to values.  
 }
 
-@defproc[(core [solution unsat?]) (or/c (listof (and/c constant? boolean?)) #f)]{
+@defproc[(core [sol unsat?]) (or/c (listof (and/c constant? boolean?)) #f)]{
 Returns the unsatisfiable core stored in the given satisfiable solution.  If the solution is 
 @racket[unsat?] and a core was computed, the result is a list of boolean values that 
 are collectively unsatisfiable.  Otherwise, the result is @racket[#f]. 
 }
 
-@defproc[(evaluate [v any/c] [solution sat?]) any/c]{
+@defproc[(evaluate [v any/c] [sol sat?]) any/c]{
 Given a Rosette value and a satisfiable solution, @racket[evaluate] produces a 
 new value obtained by replacing every symbolic constant @var[c] in @racket[v] 
-with @racket[(solution #, @var[c])] and simplifying the result.
+with @racket[(sol #, @var[c])] and simplifying the result.
+
 @examples[#:eval rosette-eval                
 (define-symbolic a b boolean?)
 (define-symbolic x y integer?)
@@ -426,22 +502,27 @@ with @racket[(solution #, @var[c])] and simplifying the result.
 (evaluate (list 4 5 x) sol)
 (define vec (vector a))
 (evaluate vec sol)
-(code:line (eq? vec (evaluate vec sol)) (code:comment "evaluation produces a new vector"))
+(code:line (eq? vec (evaluate vec sol)) (code:comment "Evaluation produces a new vector."))
 (evaluate (+ x y) sol)
 (evaluate (and a b) sol) 
 ]}
 
 @defproc[(complete-solution [sol solution?] [consts (listof constant?)]) solution?]{
-Given a solution @racket[sol] and a list of symbolic constants @racket[consts],
-returns a solution that is complete with respect to the given list.
-In particular, if @racket[sol] is satisfiable, the returned solution is also satisfiable, and
-it extends the @racket[sol] model with default bindings for all constants in @racket[consts]
-that are not bound by @racket[sol]. Otherwise, @racket[sol] itself is returned.
+                                                                                    
+ Given a solution @racket[sol] and a list of symbolic
+ constants @racket[consts], returns a solution that is
+ complete with respect to the given list. In particular, if
+ @racket[sol] is satisfiable, the returned solution is also
+ satisfiable, and it extends the @racket[sol] model with
+ default bindings for all constants in @racket[consts] that
+ are not bound by @racket[sol]. Otherwise, @racket[sol]
+ itself is returned.
+
 @examples[#:eval rosette-eval                
 (define-symbolic a boolean?)
 (define-symbolic x integer?)
 (define sol (solve (assert a)))
-(code:line sol (code:comment "no binding for x"))
+(code:line sol (code:comment "No binding for x."))
 (complete-solution sol (list a x))
 (complete-solution (solve (assert #f)) (list a x))
 ]}

rosette/guide/scribble/datatypes/solvers-log.txt

@@ -8,7 +8,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "#<z3>"))))
+  (c values c (0 (u . "#<z3>\n"))))
  #""
  #"")
 ((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -18,9 +18,31 @@
  #""
  #"")
 ((sat? sol) ((3) 0 () 0 () () (q values #t)) #"" #"")
-((evaluate (list 4 5 x) sol) ((3) 0 () 0 () () (q values (4 5 1))) #"" #"")
+((evaluate (list 4 5 x) sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(4 5 1)\n"))))
+ #""
+ #"")
 ((define vec (vector a)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((evaluate vec sol) ((3) 0 () 0 () () (c values c (v! #t))) #"" #"")
+((evaluate vec sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#(#t)\n"))))
+ #""
+ #"")
 ((eq? vec (evaluate vec sol)) ((3) 0 () 0 () () (q values #f)) #"" #"")
 ((evaluate (+ x y) sol) ((3) 0 () 0 () () (q values 3)) #"" #"")
 ((evaluate (and a b) sol)
@@ -32,7 +54,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "b"))))
+  (c values c (0 (u . "b\n"))))
  #""
  #"")
 ((define-symbolic a boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -50,7 +72,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [a #t])"))))
+  (c values c (0 (u . "(model\n [a #t])\n"))))
  #""
  #"")
 ((complete-solution sol (list a x))
@@ -62,7 +84,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [a #t]\n [x 0])"))))
+  (c values c (0 (u . "(model\n [a #t]\n [x 0])\n"))))
  #""
  #"")
 ((complete-solution (solve (assert #f)) (list a x))
@@ -74,6 +96,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")

rosette/guide/scribble/datatypes/uninterpreted-log.txt

@@ -13,7 +13,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(app f 1)"))))
+  (c values c (0 (u . "(app f 1)\n"))))
  #""
  #"")
 ((define-symbolic x real?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -26,10 +26,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "(app f (real->integer x))"))))
+  (c values c (0 (u . "(app f (real->integer x))\n"))))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -38,7 +38,7 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "(int? x)")))))
+  (c values c (0 (u . "(vc #t (int? x))\n"))))
  #""
  #"")
 ((define sol (solve (assert (not (equal? (f x) (f 1))))))
@@ -55,7 +55,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(fv integer?~>boolean?)"))))
+  (c values c (0 (u . "(fv integer?~>boolean?)\n"))))
  #""
  #"")
 ((evaluate x sol) ((3) 0 () 0 () () (q values 0)) #"" #"")
@@ -71,13 +71,7 @@
   0
   ()
   ()
-  (c
-   values
-   c
-   (0
-    (u
-     .
-     "(ite (= 1 (real->integer x)) #t (ite (= 0 (real->integer x)) #f #t))"))))
+  (c values c (0 (u . "(ite (= 1 (real->integer x)) #f #t)\n"))))
  #""
  #"")
 ((define t (~> integer? real? boolean? (bitvector 4)))
@@ -93,7 +87,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "integer?~>real?~>boolean?~>(bitvector 4)"))))
+  (c values c (0 (u . "integer?~>real?~>boolean?~>(bitvector 4)\n"))))
  #""
  #"")
 ((~> t integer?)
@@ -118,7 +112,7 @@
   ()
   (q
    exn
-   "function: expected a primitive solvable type\n  range: {[b boolean?] [(! b) real?]}"))
+   "function: expected a primitive solvable type\n  range: (union [b boolean?] [(! b) real?])"))
  #""
  #"")
 ((~> real?)
@@ -130,7 +124,7 @@
   ()
   (q
    exn
-   "~>: arity mismatch;\n the expected number of arguments does not match the given number\n  expected: at least 2\n  given: 1\n  arguments...:\n   real?"))
+   "~>: arity mismatch;\n the expected number of arguments does not match the given number\n  expected: at least 2\n  given: 1"))
  #""
  #"")
 ((define t0? (~> integer? real? boolean? (bitvector 4)))
@@ -147,7 +141,7 @@
 ((function? (if b t0? t1?)) ((3) 0 () 0 () () (q values #f)) #"" #"")
 ((function? integer?) ((3) 0 () 0 () () (q values #f)) #"" #"")
 ((function? 3) ((3) 0 () 0 () () (q values #f)) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic f (~> boolean? boolean?))
  ((3) 0 () 0 () () (c values c (void)))
  #""
@@ -164,7 +158,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "b"))))
+  (c values c (0 (u . "b\n"))))
  #""
  #"")
 ((define sol (solve (begin (assert (not (f #t))) (assert (f #f)))))
@@ -181,7 +175,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(fv boolean?~>boolean?)"))))
+  (c values c (0 (u . "(fv boolean?~>boolean?)\n"))))
  #""
  #"")
 ((fv? g) ((3) 0 () 0 () () (q values #t)) #"" #"")
@@ -194,6 +188,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")

rosette/guide/scribble/datatypes/uninterpreted.scrbl

@@ -1,15 +1,13 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/query/form rosette/query/eval rosette/solver/solution
+           rosette/base/form/define rosette/query/query rosette/solver/solution
            rosette/base/core/term (only-in rosette/query/finitize current-bitwidth)
            (only-in rosette/base/core/union union?)
            (only-in rosette/base/core/function ~> function? fv?)
-           (only-in rosette/base/base bv bitvector)
-           (only-in rosette/base/core/safe assert) 
-           (only-in rosette/base/core/bool asserts))
+           (only-in rosette/base/base bv bitvector assert vc clear-vc!))
           (for-label racket) racket/runtime-path
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+          scribble/core scribble/html-properties scribble/examples racket/sandbox
           "../util/lifted.rkt")
 
 @(define-runtime-path root ".")
@@ -19,7 +17,7 @@
 
 @declare-exporting[rosette/base/base #:use-sources (rosette/base/core/function
                                                     rosette/query/finitize
-                                                    rosette/base/core/safe)]
+                                                    rosette/base/base)]
 
 In Rosette, functions are special kinds of @seclink["sec:proc"]{procedures} that are pure
 (have no side effects) and total (defined on every input value).
@@ -35,54 +33,60 @@ as the result of a @seclink["sec:queries"]{solver-aided query}.
 
 @examples[#:eval rosette-eval
 (current-bitwidth #f)
-(code:comment "an uninterpreted function from integers to booleans:")
+(code:comment "An uninterpreted function from integers to booleans:")
 (define-symbolic f (~> integer? boolean?))
-(code:line (f 1)     (code:comment "no built-in interpretation for 1"))
+(code:line (f 1)     (code:comment "No built-in interpretation for 1."))
 (define-symbolic x real?)
-(code:line (f x)     (code:comment "this typechecks when x is an integer"))
-(code:line (asserts) (code:comment "so Rosette emits the corresponding assertion"))
+(code:line (f x)     (code:comment "This typechecks when x is an integer,"))
+(code:line (vc)      (code:comment "so Rosette emits the corresponding assertion."))
 (define sol (solve (assert (not (equal? (f x) (f 1))))))
-(code:line (define g (evaluate f sol)) (code:comment "an interpretation of f"))
+(code:line (define g (evaluate f sol)) (code:comment "An interpretation of f."))
 g
 (evaluate x sol)
-(code:line (fv? f)   (code:comment "f is a function value"))
-(code:line (fv? g)   (code:comment "and so is g"))
-(code:line (g 2)     (code:comment "we can apply g to concrete values"))
-(code:line (g x)     (code:comment "and to symbolic values"))] 
+(code:line (fv? f)   (code:comment "f is a function value,"))
+(code:line (fv? g)   (code:comment "and so is g."))
+(code:line (g 2)     (code:comment "We can apply g to concrete values"))
+(code:line (g x)     (code:comment "and to symbolic values."))] 
 
 @defproc[(~> [d (and/c solvable? (not/c function?))] ...+
              [r (and/c solvable? (not/c function?))]) function?]{
+                                                                 
   Returns a type predicate for recognizing functions that take as input
   values of types @racket[d...+] and produce values of type @racket[r].
   The domain and range arguments must be concrete @racket[solvable?] types that are
   not themselves functions. Note that @racket[~>] expects at least one domain
   type to be given, disallowing zero-argument functions.
+  
   @examples[#:eval rosette-eval
   (define t (~> integer? real? boolean? (bitvector 4)))
   t
-  (~> t integer?)
+  (eval:error (~> t integer?))
   (define-symbolic b boolean?)
-  (~> integer? (if b boolean? real?))
-  (~> real?)]
+  (eval:error (~> integer? (if b boolean? real?)))
+  (eval:error (~> real?))]
 }
 
 @defproc[(function? [v any/c]) boolean?]{
+                                         
   Returns true if @racket[v] is a concrete type predicate that recognizes function values.
+                  
   @examples[#:eval rosette-eval
   (define t0? (~> integer? real? boolean? (bitvector 4)))
   (define t1? (~> integer? real?))
   (function? t0?)
   (function? t1?)
   (define-symbolic b boolean?)
-  (code:line (function? (if b t0? t1?)) (code:comment "not a concrete type"))
-  (code:line (function? integer?)       (code:comment "not a function type"))
-  (code:line (function? 3)              (code:comment "not a type"))]
+  (code:line (function? (if b t0? t1?)) (code:comment "Not a concrete type."))
+  (code:line (function? integer?)       (code:comment "Not a function type."))
+  (code:line (function? 3)              (code:comment "Not a type."))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(fv? [v any/c]) boolean?]{
+                                   
   Returns true if @racket[v] is a concrete or symbolic function value.
+                  
   @examples[#:eval rosette-eval
   (define-symbolic f (~> boolean? boolean?))
   (fv? f)
@@ -95,9 +99,9 @@ g
        (assert (not (f #t)))
        (assert (f #f)))))
   (define g (evaluate f sol))
-  (code:line g (code:comment "g implements logical negation"))
+  (code:line g (code:comment "g implements logical negation."))
   (fv? g)
-  (code:comment "verify that g implements logical negation:")
+  (code:comment "Verify that g implements logical negation:")
   (verify (assert (equal? (g b) (not b))))]
 }
 

rosette/guide/scribble/datatypes/vectors-log.txt

@@ -28,6 +28,300 @@
  #""
  #"")
 ((evaluate n sol) ((3) 0 () 0 () () (q values 1)) #"" #"")
-((evaluate (list x y z) sol) ((3) 0 () 0 () () (q values (4 0 0))) #"" #"")
-((evaluate vs sol) ((3) 0 () 0 () () (c values c (v! 4))) #"" #"")
-((evaluate xs sol) ((3) 0 () 0 () () (q values (4))) #"" #"")
+((evaluate (list x y z) sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(4 0 0)\n"))))
+ #""
+ #"")
+((evaluate vs sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#(4)\n"))))
+ #""
+ #"")
+((evaluate xs sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(4)\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define xs (if b (vector 1 2) (vector 3 4 5 6)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(xs
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(union [b #(1 2)] [(! b) #(3 4 5 6)])\n"))))
+ #""
+ #"")
+((integer->bitvector (vector-length xs) (bitvector 4))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(integer->bitvector (ite b 2 4) (bitvector 4))\n"))))
+ #""
+ #"")
+((vector-length-bv xs (bitvector 4))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(ite b (bv #x2 4) (bv #x4 4))\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic p (bitvector 1))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define xs (vector 1 2 3 4)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vector-ref xs (bitvector->natural p))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(ite*\n (⊢ (= 0 (bitvector->natural p)) 1)\n (⊢ (= 1 (bitvector->natural p)) 2)\n (⊢ (= 2 (bitvector->natural p)) 3)\n (⊢ (= 3 (bitvector->natural p)) 4))\n\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vc #t (&& (<= 0 (bitvector->natural p)) (< (bitvector->natural p) 4)))\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vector-ref-bv xs p)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(ite* (⊢ (bveq (bv #b0 1) p) 1) (⊢ (bveq (bv #b1 1) p) 2))\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic q (bitvector 4))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((vector-ref-bv xs q)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(ite*\n (⊢ (bveq (bv #x0 4) q) 1)\n (⊢ (bveq (bv #x1 4) q) 2)\n (⊢ (bveq (bv #x2 4) q) 3)\n (⊢ (bveq (bv #x3 4) q) 4))\n\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t (bvult q (bv #x4 4)))\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic p (bitvector 1))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define xs (vector 1 2 3 4)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vector-set! xs (bitvector->natural p) 5)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(xs
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vector\n (ite (= 0 (bitvector->natural p)) 5 1)\n (ite (= 1 (bitvector->natural p)) 5 2)\n (ite (= 2 (bitvector->natural p)) 5 3)\n (ite (= 3 (bitvector->natural p)) 5 4))\n\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vc #t (&& (<= 0 (bitvector->natural p)) (< (bitvector->natural p) 4)))\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define xs (vector 1 2 3 4)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vector-set!-bv xs p 5) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(xs
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vector (ite (bveq (bv #b0 1) p) 5 1) (ite (bveq (bv #b1 1) p) 5 2) 3 4)\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic q (bitvector 4))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define xs (vector 1 2 3 4)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vector-set!-bv xs q 5) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(xs
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vector\n (ite (bveq (bv #x0 4) q) 5 1)\n (ite (bveq (bv #x1 4) q) 5 2)\n (ite (bveq (bv #x2 4) q) 5 3)\n (ite (bveq (bv #x3 4) q) 5 4))\n\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t (bvult q (bv #x4 4)))\n"))))
+ #""
+ #"")

rosette/guide/scribble/datatypes/vectors.scrbl

@@ -3,9 +3,13 @@
 @(require (for-label 
            rosette/base/form/define rosette/query/query 
            rosette/base/core/term
-           (only-in rosette/base/core/safe assert) 
+           rosette/solver/solution
+           (only-in rosette/base/base assert define-symbolic union?
+                    vc clear-vc! bitvector bitvector? bv?
+                    bitvector->natural integer->bitvector
+                    vector-length-bv vector-ref-bv vector-set!-bv) 
            racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox racket/runtime-path
+          scribble/core scribble/html-properties scribble/examples racket/sandbox racket/runtime-path
           "../util/lifted.rkt")
 
 
@@ -46,8 +50,8 @@ if they have the same length and @racket[equal?] contents.
 
 @examples[#:eval rosette-eval
 (define-symbolic x y z n integer?)
-(code:line (define xs (take (list x y z) n))        (code:comment "xs is a symbolic list"))
-(code:line (define vs (list->vector xs))            (code:comment "vs is a symbolic vector"))
+(code:line (define xs (take (list x y z) n))        (code:comment "xs is a symbolic list."))
+(code:line (define vs (list->vector xs))            (code:comment "vs is a symbolic vector."))
 (define sol
   (solve
    (begin
@@ -58,8 +62,74 @@ if they have the same length and @racket[equal?] contents.
 (evaluate vs sol)
 (evaluate xs sol)]
 
+@section{Lifted Operations on Vectors}
+
 The following vector operations are lifted to work on both concrete and symbolic values:
 @tabular[#:style (style #f (list (attributes '((id . "lifted")(class . "boxed")))))
-(list (list @elem{@vector-ops,  @more-vector-ops}))]
+(list (list @elem{Vector Operations} @elem{@vector-ops,  @more-vector-ops}))]
+
+@(rosette-eval '(clear-vc!))
+
+@section{Additional Operations on Vectors}
+
+Rosette provides the following procedures for operating on vectors using @seclink["sec:bitvectors"]{bitvector} indices and lengths. These procedures produce symbolic values that avoid @racketlink[bitvector->natural]{casting} their bitvector arguments to integers, leading to @seclink["sec:notes"]{more efficiently solvable queries}.
+
+@declare-exporting[rosette/base/base #:use-sources (rosette/base/base)]
+
+
+@defproc[(vector-length-bv [vec vector?] [t (or/c bitvector? union?)]) bv?]{
+Equivalent to @racket[(integer->bitvector (vector-length vec) t)] but avoids the @racket[integer->bitvector] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic b boolean?)
+(define xs (if b (vector 1 2) (vector 3 4 5 6)))
+xs
+(integer->bitvector (vector-length xs) (bitvector 4))
+(vector-length-bv xs (bitvector 4))]
+}
+
+@(rosette-eval '(clear-vc!))
+@defproc[(vector-ref-bv [vec vector?] [pos bv?]) any/c]{
+Equivalent to @racket[(vector-ref vec (bitvector->natural pos))] but avoids the @racket[bitvector->natural] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs (vector 1 2 3 4))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(vector-ref xs (bitvector->natural p))
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(vector-ref-bv xs p)
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(vector-ref-bv xs q)
+(vc)]
+}
+
+@(rosette-eval '(clear-vc!))
+@defproc[(vector-set!-bv [vec vector?] [pos bv?] [val any/c]) void?]{
+Equivalent to @racket[(vector-set! vec (bitvector->natural pos) val)] but avoids the @racket[bitvector->natural] cast for better solving performance.
+
+@examples[#:eval rosette-eval
+(define-symbolic p (bitvector 1))
+(define xs (vector 1 2 3 4))
+(code:comment "Uses a cast and generates a redundant assertion on the range of p:")
+(vector-set! xs (bitvector->natural p) 5)
+xs
+(vc)
+(clear-vc!)
+(code:comment "No cast and no redundant range assertion:")
+(define xs (vector 1 2 3 4))
+(vector-set!-bv xs p 5)
+xs
+(vc)
+(code:comment "But the range assertion is generated when needed:")
+(define-symbolic q (bitvector 4))
+(define xs (vector 1 2 3 4))
+(vector-set!-bv xs q 5)
+xs
+(vc)]              
+}
 
-@(kill-evaluator rosette-eval)

rosette/guide/scribble/error-tracing/error-tracer-log.txt

@@ -1,5 +1,9 @@
 ;; This file was created by make-log-based-eval
-((define-symbolic xs integer? (4))
+((require (only-in rosette/guide/scribble/util/lifted format-opaque))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic xs integer? #:length 4)
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
@@ -13,7 +17,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model)"))))
+  (c values c (0 (u . "(model)\n"))))
  #""
  #"")
 ((define-symbolic opt boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -30,14 +34,41 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
-((verify
-  #:assume
-  (assert (positive? (sum xs)))
-  #:guarantee
-  (assert (ormap positive? xs)))
+((require rackunit) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (post xs) (assert (= (sum xs) (sum (filter-not zero? xs)))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (query xs) (verify (post xs)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define example-tests
+   (test-suite
+    "An example suite for a sum query."
+    #:before
+    clear-vc!
+    #:after
+    clear-vc!
+    (test-case
+     "Test sum with concrete values."
+     (check = (sum '()) 0)
+     (check = (sum '(-1)) -1)
+     (check = (sum '(-2 2)) 0)
+     (check = (sum '(-1 0 3)) 2))
+    (test-case
+     "Test query post for exceptions."
+     (before (clear-vc!) (check-not-exn (thunk (post xs)))))
+    (test-case
+     "Test query outcome."
+     (before (clear-vc!) (check-pred unsat? (query xs))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((format-opaque "~a" (run-test example-tests))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -46,51 +77,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
- #""
- #"")
-((require rackunit) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (assumed xs) (assert (positive? (sum xs))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (guaranteed xs) (assert (ormap positive? xs)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (query xs) (verify #:assume (assumed xs) #:guarantee (guaranteed xs)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define example-tests
-   (test-suite
-    "An example suite for a sum query."
-    #:before
-    clear-asserts!
-    #:after
-    clear-asserts!
-    (test-case
-     "Test sum with concrete values."
-     (check = (sum '()) 0)
-     (check = (sum '(-1)) -1)
-     (check = (sum '(-2 2)) 0)
-     (check = (sum '(-1 0 3)) 2))
-    (test-case
-     "Test query parts for exceptions."
-     (check-not-exn (thunk (assumed xs)))
-     (check-not-exn (thunk (guaranteed xs))))
-    (test-case "Test query outcome." (check-pred unsat? (query xs)))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-('(|#<test-error>| |#<test-failure>| |#<test-success>|)
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q values (|#<test-error>| |#<test-failure>| |#<test-success>|)))
+  (c values c (0 (u . "(#<test-error> #<test-failure> #<test-failure>)\n"))))
  #""
  #"")
 ((define (sum xs)
@@ -102,25 +89,8 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-('(|#<test-success>| |#<test-success>| |#<test-success>|)
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q values (|#<test-success>| |#<test-success>| |#<test-success>|)))
- #""
- #"")
-((test-case "Test sum for any failures." (check-pred unsat? (verify (sum xs))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((verify
-  #:assume
-  (assert (positive? (sum xs)))
-  #:guarantee
-  (assert (ormap positive? xs)))
+((assume (positive? (sum xs))) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((verify (assert (ormap positive? xs)))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -129,7 +99,94 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((define (pre xs) (assume (positive? (sum xs))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (post xs) (assert (ormap positive? xs)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (query xs) (pre xs) (verify (post xs)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define example-tests
+   (test-suite
+    "An example suite for a sum query."
+    #:before
+    clear-vc!
+    #:after
+    clear-vc!
+    (test-case
+     "Test sum with concrete values."
+     (check = (sum '()) 0)
+     (check = (sum '(-1)) -1)
+     (check = (sum '(-2 2)) 0)
+     (check = (sum '(-1 0 3)) 2))
+    (test-case
+     "Test query post for exceptions."
+     (before (clear-vc!) (check-not-exn (thunk (pre xs)))))
+    (test-case
+     "Test query post for exceptions."
+     (before (clear-vc!) (check-not-exn (thunk (post xs)))))
+    (test-case
+     "Test query outcome."
+     (before (clear-vc!) (check-pred unsat? (query xs))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((format-opaque "~a" (run-test example-tests))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(#<test-success> #<test-success> #<test-success> #<test-success>)\n"))))
+ #""
+ #"")
+((test-case "Test sum for any failures." (check-pred unsat? (verify (sum xs))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"--------------------\nTest sum for any failures.\nFAILURE\nname:       check-pred\nlocation:   eval:20:0\nparams:\n  '(#<procedure:unsat?> (model\n   [xs$0 0]\n   [xs$1 0]\n   [xs$2 0]\n   [xs$3 0]))\n--------------------\n")
+((verify (begin (assume (positive? (sum xs))) (assert (ormap positive? xs))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [xs$0 1]\n [xs$1 1]\n [xs$2 1]\n [xs$3 1])\n"))))
+ #""
+ #"")
+((assume (positive? (sum xs))) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((verify (assert (ormap positive? xs)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
 ((define (select xs n)
@@ -148,11 +205,12 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((verify
-  #:assume
-  (assert (and (<= 0 n (sub1 (length xs))) (= k (select xs n))))
-  #:guarantee
-  (assert (= k (list-ref (sort xs <) n))))
+((define-symbolic n k integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume (and (<= 0 n (sub1 (length xs))) (= k (select xs n))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((verify (assert (= k (list-ref (sort xs <) n))))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -161,6 +219,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")

rosette/guide/scribble/error-tracing/error-tracing.scrbl

@@ -1,18 +1,14 @@
 #lang scribble/manual
 
 @(require scribble/core scribble/html-properties
-          scribble/bnf scribble/example scriblib/footnote
+          scribble/bnf scribble/example 
           (for-label (except-in racket list-set) errortrace
                      rosette/base/core/term
                      rosette/base/form/define
                      rosette/query/form
-                     (only-in rosette/query/debug debug)
                      rosette/base/core/union
-                     (only-in rosette unsat model evaluate sat? unsat? clear-asserts!)
-                     (only-in rosette/query/finitize current-bitwidth)
-                     (only-in rosette/base/base bitvector)
-                     (only-in rosette/base/core/safe assert)
-                     (only-in rosette/base/core/forall for/all)
+                     (only-in rosette unsat model evaluate sat? unsat? clear-vc! current-bitwidth)
+                     (only-in rosette/base/base assume assert vc clear-vc!)
                      rackunit)
           racket/runtime-path
           "../util/lifted.rkt")
@@ -23,6 +19,8 @@
 @(define-runtime-path interface.png "interface.png")
 @(define-runtime-path quickselect.png "quickselect.png")
 
+@(rosette-eval '(require (only-in rosette/guide/scribble/util/lifted format-opaque)))
+
 @title[#:tag "ch:error-tracing"]{Debugging}
 
 Bugs in Rosette programs often manifest as runtime
@@ -30,15 +28,14 @@ exceptions. For example, calling a procedure with too few
 arguments will cause a runtime exception in Rosette, just as
 it would in Racket. But unlike Racket, Rosette treats
 exceptions as assertion failures: it catches the exception,
-adds the (path) condition under which the exception is
-thrown to the @tech{assertion store}, and proceeds with
-symbolic evaluation. This treatment of exceptions
-ensures that the program's
-@seclink["ch:syntactic-forms:rosette"]{solver-aided queries}
-correctly return a @racket[sat?] or @racket[unsat?]
+updates the @tech{verification condition} to reflect the
+failure, and proceeds with symbolic evaluation. This
+treatment of exceptions ensures that the program's
+@seclink["ch:syntactic-forms:rosette"]{ solver-aided
+ queries} correctly return a @racket[sat?] or @racket[unsat?]
 solution, but it can also make solver-aided code tricky to
-debug. This chapter describes common problems that are due to
-intercepted exceptions, how to test for them, and how to
+debug. This chapter describes common problems that are due
+to intercepted exceptions, how to test for them, and how to
 find them with the @code{symtrace} tool for error tracing.
 
 
@@ -62,8 +59,8 @@ As an example, consider the following verification query,
 which tries to prove that the sum of a list of integers
 remains the same when all zeros are removed from the list:
 
-@examples[#:label #f #:eval rosette-eval
-(define-symbolic xs integer? [4])
+@examples[#:eval rosette-eval #:label #f 
+(define-symbolic xs integer? #:length 4)
 (code:line (define (sum xs) (foldl + xs)) (code:comment "bug: missing 0 after +"))
 (verify (assert (= (sum xs) (sum (filter-not zero? xs)))))
 ]
@@ -78,7 +75,7 @@ arguments. This omission will cause every call to
 @racket[sum] to raise an exception, including 
 @racket[(sum xs)] in the body of our query. Rosette
 intercepts this exception and adds @racket[#f] to the
-query's @tech{assertion store} because the exception
+query's @tech{verification condition} because the exception
 happens unconditionally (on all paths).
 This false assertion then causes the query to return a
 trivial counterexample, @racket[(model)], indicating that
@@ -88,7 +85,7 @@ to an error.
 As another example, consider the following synthesis query
 involving @racket[sum]:
 
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f 
 (define-symbolic opt boolean?)
 (synthesize
  #:forall xs
@@ -99,62 +96,33 @@ Here, the expected result is a model that binds @racket[opt]
 to the value @racket[#t], and this is the outcome we see
 once we fix the bug in @racket[sum]. The bug, however,
 causes the @racket[#:guarantee] expression to fail
-unconditionally. The query then intercepts the exception and
+unconditionally. Rosette then intercepts the exception and
 returns @racket[(unsat)] to indicate that no choice of
 @racket[opt] can satisfy the specification.
 
-In addition to unexpected results, exceptions intercepted in
-queries can also lead to more subtle errors, with no obvious
-manifestation. For example, consider the following query
-that verifies another simple property of @racket[sum]---if
-@racket[sum] returns a positive integer, then at least one
-of its arguments must have been positive.
+Bugs of this kind can be found through testing. A good test
+suite should check that queries produce expected results on
+small inputs, and that query parts do not throw exceptions.
+When possible, it is also good practice to test all
+solver-aided code against concrete inputs and outputs. Here
+is an example test suite for our first query that includes
+all of these checks:
 
-@examples[#:label #f #:eval rosette-eval
-(verify
- #:assume (assert (positive? (sum xs)))
- #:guarantee (assert (ormap positive? xs)))
-]
-
-This query returns @racket[(unsat)], as expected, despite the
-bug in @racket[sum]. To see why, recall that the verifier
-returns a counterexample when it can find an input that
-satisfies the @racket[#:assume]d assertions and violates the
-@racket[#:guarantee]d assertions. But there is no input that
-satisfies the assumptions in our query: as before, the call
-to @racket[(sum xs)] throws an unconditional exception that
-is intercepted and treated as @racket[(assert #f)]. This
-false assumption leads to a vacuous proof of correctness,
-and the verifier returns @racket[(unsat)].
-
-The bugs due to query exceptions can generally be found
-through testing. To guard against such bugs, a test suite
-should check that queries produce expected results on small
-inputs, and it should also check for unexpected exceptions
-in all parts of the query's body. When possible, it is also
-good practice to test all solver-aided code against concrete
-inputs and outputs. Here is an example test suite for our
-last query that includes all of these checks:
-
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f 
 (eval:no-prompt
 (require rackunit)
 
-(define (assumed xs)
-  (assert (positive? (sum xs))))
-
-(define (guaranteed xs)
-  (assert (ormap positive? xs)))
+(define (post xs)
+  (assert (= (sum xs) (sum (filter-not zero? xs)))))
 
 (define (query xs)
-  (verify #:assume (assumed xs)
-          #:guarantee (guaranteed xs)))
+  (verify (post xs)))
    
 (define example-tests 
   (test-suite
    "An example suite for a sum query."
-   #:before clear-asserts!
-   #:after  clear-asserts!
+   #:before clear-vc!
+   #:after  clear-vc!
 
    (test-case
     "Test sum with concrete values."
@@ -164,19 +132,23 @@ last query that includes all of these checks:
     (check = (sum '(-1 0 3)) 2))
      
    (test-case
-    "Test query parts for exceptions."
-    (check-not-exn (thunk (assumed xs)))
-    (check-not-exn (thunk (guaranteed xs))))
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (post xs)))))
   
    (test-case
     "Test query outcome."
-    (check-pred unsat? (query xs))
-    ))))
+    (before
+     (clear-vc!)
+     (check-pred unsat? (query xs)))))))
 
-(eval:alts (run-test example-tests) '(\#<test-error> \#<test-failure> \#<test-success>))
+(eval:alts
+ (run-test example-tests)
+ (format-opaque "~a" (run-test example-tests)))
 ]
 
-All but the last test in this suite fail when invoked on the
+All tests in this suite fail when invoked on the
 buggy @racket[sum], and they all pass once the bug is fixed.
 
 
@@ -192,45 +164,115 @@ trickier, in both concrete and solver-aided code, as our next
 example shows.
 
 Consider the following buggy version of @racket[sum]:
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f 
 (define (sum xs)
   (cond
     [(null? xs) 0]
     [(null? (cdr xs)) (car xs)] 
     [(andmap (curry = (car xs)) (cdr xs))  
-     (* (length xs) (cdr xs))] (code:comment "bug: cdr should be car")
+     (* (length xs) (cdr xs))] (code:comment "Bug: cdr should be car.")
     [else (apply + xs)]))
 ]
 
 This version of @racket[sum] implements three simple
-optimizations. It returns 0 when given an empty list; @code{
- xs[0]} when given a list of length 1; and @code{|xs| * xs[0]}
-when given a list of identical elements. This last
-optimization is buggy (it uses @racket[cdr] when it should
-have used @racket[car]), and any execution path that goes
-through it will end with an exception.
+optimizations. It returns 0 when given an empty list;
+@code{xs[0]} when given a list of length 1; and
+@code{|xs| * xs[0]} when given a list of identical elements.
+This last optimization is buggy (it uses @racket[cdr] when
+it should have used @racket[car]), and any execution path
+that goes through it will end with an exception.
 
-Our test suite from the
-@seclink["sec:errors-under-queries"]{previous section} will
+Suppose that we want to verify another simple property of
+@racket[sum]: if it returns a positive integer, then at least
+one element in the argument list must have been positive.
+
+@examples[#:eval rosette-eval #:label #f 
+(assume (positive? (sum xs)))
+(verify
+ (assert (ormap positive? xs)))]
+
+This query returns @racket[(unsat)], as expected, despite
+the bug in @racket[sum]. To see why, recall that
+@racket[(verify #, @var{expr})] searches for an input that
+violates an assertion in @var{expr}, while satisfying all
+the assumptions and assertions accumulated in the
+verification condition @racket[(vc)] before the call to
+@racket[verify]. So, our query is @racket[unsat?] because
+@racket[(ormap positive? xs)] holds whenever
+@racket[(sum xs)] successfully computes a positive value.
+
+A basic test suite, adapted from the
+@seclink["sec:errors-under-queries"]{previous section}, will
 not uncover this bug. If we run the tests against the new
 @racket[sum], all the checks pass:
 
-@examples[#:label #f #:eval rosette-eval
-(eval:alts (run-test example-tests)
-           '(\#<test-success> \#<test-success> \#<test-success>))
+@examples[#:eval rosette-eval #:label #f 
+(eval:no-prompt
+(define (pre xs)
+  (assume (positive? (sum xs))))
+  
+(define (post xs)
+  (assert (ormap positive? xs)))
+
+(define (query xs)
+  (pre xs)
+  (verify (post xs)))
+
+(define example-tests 
+  (test-suite
+   "An example suite for a sum query."
+   #:before clear-vc!
+   #:after  clear-vc!
+
+   (test-case
+    "Test sum with concrete values."
+    (check = (sum '()) 0)
+    (check = (sum '(-1)) -1)
+    (check = (sum '(-2 2)) 0)
+    (check = (sum '(-1 0 3)) 2))
+
+   (test-case
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (pre xs)))))
+      
+   (test-case
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (post xs)))))
+  
+   (test-case
+    "Test query outcome."
+    (before
+     (clear-vc!)
+     (check-pred unsat? (query xs)))))))
+
+(eval:alts
+ (run-test example-tests)
+ (format-opaque "~a" (run-test example-tests)))
 ] 
 
 One way to detect bugs of this kind is to run a "unit
 verification query" for each key procedure in the program,
 searching for assertion failures where none are expected:
 
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f 
 (test-case
  "Test sum for any failures."
  (check-pred unsat? (verify (sum xs))))
 ]
 
-But writing such queries is not always possible, or
+Another strategy is to avoid issuing any assumptions or
+assertions outside of queries:
+@examples[#:eval rosette-eval #:label #f 
+(verify
+ (begin
+   (assume (positive? (sum xs)))
+   (assert (ormap positive? xs))))]
+
+But neither strategy is always possible, or
 foolproof, for large programs. So, in addition to testing,
 we recommend debugging all important queries with 
 @tech[#:key "error tracer"]{error tracing}. 
@@ -256,15 +298,12 @@ The error tracer will open a web browser and stream
 all exceptions that Rosette intercepted. For instance,
 here is the output from the error tracer when running our
 last query on the buggy @racket[sum] example from the
-@seclink["sec:errors-under-symbolic-eval"]{previous
- section}:
+@seclink["sec:errors-under-symbolic-eval"]{previous section}:
 
-
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(assume (positive? (sum xs)))
 (verify
- #:assume (assert (positive? (sum xs)))
- #:guarantee (assert (ormap positive? xs)))
-]
+ (assert (ormap positive? xs)))]
 
 @(image interface.png #:scale 0.5)
 
@@ -301,9 +340,9 @@ The @exec{raco symtrace @nonterm{prog}} command accepts the following command-li
  @item{@DFlag{racket} --- instrument code in any language, not
   just those derived from Rosette.}
 
- @item{@DFlag{solver} --- do not show exceptions raised on
+ @;{@item{@DFlag{solver} --- do not show exceptions raised on
   infeasible paths, using the solver to decide if paths are
-  feasible. This option can cause significant performance degradation.}
+  feasible. This option can cause significant performance degradation.}}
 
  @item{@DFlag{assert} --- do not show exceptions due to
   assertion errors, which are usually expected exceptions.}
@@ -332,7 +371,7 @@ verifying the following buggy implementation of the
 @link["https://en.wikipedia.org/wiki/Quickselect"]{
  quickselect algorithm}.
 
-@examples[#:label #f #:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (define (select xs n)
   (cond
     [(empty? xs) (assert #f "unexpected empty list")]
@@ -343,62 +382,39 @@ verifying the following buggy implementation of the
           (define len< (length <pivot))
           (cond
             [(= n len<) pivot]
-            [(< n len<) (select <pivot)] (code:comment "bug: should be (select <pivot n)")
+            [(< n len<) (select <pivot)] (code:comment "Bug: should be (select <pivot n).")
             [else (select >=pivot (- n len< 1))])]))
 
-(verify
- #:assume (assert (and (<= 0 n (sub1 (length xs)))
+(define-symbolic n k integer?)
+
+(assume
+ (and (<= 0 n (sub1 (length xs)))
       (= k (select xs n))))
- #:guarantee (assert (= k (list-ref (sort xs <) n))))
+
+(verify
+ (assert (= k (list-ref (sort xs <) n))))
 ]
 
 As before, the verification query succeeds despite the bug.
-But unlike before, the bug is much harder to detect. So we
+But unlike before, the bug is harder to detect. So we
 run the error tracer on it and obtain the following output:
 
 @(image quickselect.png #:scale 0.5)
 
-The output from the error tracer includes 9 exceptions. Four
+The output from the error tracer includes 8 exceptions. Four
 are arity mismatch exceptions that are due to the bug, and
 the rest are benign assertion failures that cannot happen in
-any concrete execution.
+our example.
 
 Because benign assertion failures are so common, the error
-tracer provides an option to suppress them from the output
-via the @seclink["sec:symtrace:opts"]{@DFlag{assert}}
-flag. With the flag enabled, the output contains only the
-four arity mismatch exceptions.
+tracer provides an option to heuristically suppress them
+from the output via the
+@seclink["sec:symtrace:opts"]{@DFlag{assert}} flag. With the
+flag enabled, the output contains only the four arity
+mismatch exceptions.
 
-@define-footnote[pc-note make-pc-note]
+Some assertion failures are bugs, however, so filtering with
+@DFlag{assert} can end up hiding true positives and should
+be used with this caveat in mind.
 
-Some assertion failures are bugs, however, so aggressive
-filtering with @DFlag{assert} can end up hiding true
-positives. For this reason, the error tracer also includes a
-more conservative filtering option, @DFlag{solver}, that
-will never miss true positives, at the cost of showing more
-false alarms. The @DFlag{solver} option suppresses
-exceptions that are raised on paths with
-@seclink["sec:state-reflection"]{infeasible path
- conditions}, which involves calling the solver to check the
-feasibility of the path condition for each
-exception.@pc-note{Exceptions with infeasible path
- conditions are guaranteed to be unreachable, so no true
- positive are missed. But exceptions with feasible path
- conditions may still be unreachable due to the way that
- Rosette represents symbolic state, so some false positives
- may be included in the output.} Solver calls are expensive,
-however, so enabling this flag can cause significant
-performance degradation. In our example, using the @DFlag{solver}
-flag is both fast and effective at pruning false
-positives: it suppresses all the assertion failures as well
-as one of the arity mismatch errors.
 
-Lastly, it is possible to use both of these filtering flags,
-@DFlag{solver} and @DFlag{assert}, together. In our case,
-the result is the same as using the @DFlag{solver} flag
-alone. But in general, using both flags can lead to better
-performance compared to using @DFlag{solver} alone, with the
-caveat that the inclusion of @DFlag{assert} may filter out
-true positives.
-
-@make-pc-note[]

rosette/guide/scribble/error-tracing/select.rkt

@@ -0,0 +1,24 @@
+#lang rosette
+
+(define-symbolic xs integer? #:length 4)
+(define-symbolic k integer?)
+(define-symbolic n integer?)
+
+(define (select xs n)
+  (cond
+    [(empty? xs) (assert #f "unexpected empty list")]
+    [else (define pivot (first xs))
+          (define non-pivot (rest xs))
+          (define <pivot (filter (λ (x) (< x pivot)) non-pivot))
+          (define >=pivot (filter (λ (x) (>= x pivot)) non-pivot))
+          (define len< (length <pivot))
+          (cond
+            [(= n len<) pivot]
+            [(< n len<) (select <pivot)]
+            [else (select >=pivot (- n len< 1))])]))
+
+(assume (and (<= 0 n (sub1 (length xs)))
+             (= k (select xs n))))
+
+(verify (assert (= k (list-ref (sort xs <) n))))
+

rosette/guide/scribble/error-tracing/sum.rkt

@@ -0,0 +1,15 @@
+#lang rosette
+
+(define (sum xs)
+  (cond
+    [(null? xs) 0]
+    [(null? (cdr xs)) (car xs)] 
+    [(andmap (curry = (car xs)) (cdr xs))  
+     (* (length xs) (cdr xs))] 
+    [else (apply + xs)]))
+
+(define-symbolic xs integer? #:length 4)
+
+(assume (positive? (sum xs)))
+
+(verify (assert (ormap positive? xs)))

rosette/guide/scribble/error-tracing/test.rkt

@@ -0,0 +1,96 @@
+#lang rosette
+
+(define (sum0 xs) (foldl + xs))
+(define (sum1 xs) (foldl + 0 xs))
+
+(define (sum2 xs)
+  (cond
+    [(null? xs) 0]
+    [(null? (cdr xs)) (car xs)] 
+    [(andmap (curry = (car xs)) (cdr xs))  
+     (* (length xs) (cdr xs))] 
+    [else (apply + xs)]))
+
+(define-symbolic xs integer? #:length 4)
+
+(require rackunit)
+
+(define (tests0 sum)
+  
+  (define (post xs)
+    (assert (= (sum xs) (sum (filter-not zero? xs)))))
+
+  (define (query xs)
+    (verify (post xs)))
+   
+  (test-suite
+   "An example suite for a sum query."
+   #:before clear-vc!
+   #:after  clear-vc!
+
+   (test-case
+    "Test sum with concrete values."
+    (check = (sum '()) 0)
+    (check = (sum '(-1)) -1)
+    (check = (sum '(-2 2)) 0)
+    (check = (sum '(-1 0 3)) 2))
+     
+   (test-case
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (post xs)))))
+  
+   (test-case
+    "Test query outcome."
+    (before
+     (clear-vc!)
+     (check-pred unsat? (query xs))))))
+
+
+(define (tests1 sum)
+
+  (define (pre xs)
+    (assume (positive? (sum xs))))
+  
+  (define (post xs)
+    (assert (ormap positive? xs)))
+
+  (define (query xs)
+    (pre xs)
+    (verify (post xs)))
+   
+  (test-suite
+   "An example suite for a sum query."
+   #:before clear-vc!
+   #:after  clear-vc!
+
+   (test-case
+    "Test sum with concrete values."
+    (check = (sum '()) 0)
+    (check = (sum '(-1)) -1)
+    (check = (sum '(-2 2)) 0)
+    (check = (sum '(-1 0 3)) 2))
+
+   (test-case
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (pre xs)))))
+      
+   (test-case
+    "Test query post for exceptions."
+    (before
+     (clear-vc!)
+     (check-not-exn (thunk (post xs)))))
+  
+   (test-case
+    "Test query outcome."
+    (before
+     (clear-vc!)
+     (check-pred unsat? (query xs))))))
+
+(run-test (tests0 sum0))
+(run-test (tests0 sum1))
+(run-test (tests0 sum2))
+(run-test (tests1 sum2))

rosette/guide/scribble/essentials/bvmid.rkt

@@ -0,0 +1,202 @@
+#lang rosette
+
+(require (only-in racket/sandbox with-deep-time-limit))
+(require rosette/solver/smt/z3)
+(require rosette/guide/scribble/util/demo)
+(require rosette/lib/synthax)
+
+
+(provide (all-defined-out))
+  
+(define int32? (bitvector 32))
+
+(define (int32 i)
+  (bv i int32?))
+
+(define (bvmid lo hi)
+  (bvsdiv (bvadd lo hi) (int32 2)))
+
+(define (bvmid-no-overflow lo hi)
+  (bvadd lo (bvsdiv (bvsub hi lo) (int32 2))))
+
+(define (check-mid impl lo hi)        
+  (assume (bvsle (int32 0) lo))                  
+  (assume (bvsle lo hi))              
+  (define mi (impl lo hi))           
+  (define diff                        
+    (bvsub (bvsub hi mi)             
+           (bvsub mi lo)))
+  (assert (bvsle lo mi))
+  (assert (bvsle mi hi))
+  (assert (bvsle (int32 0) diff))     
+  (assert (bvsle diff (int32 1))))
+
+(define-symbolic l h int32?)
+
+(define-grammar (fast-int32 x y)
+  [expr (choose
+         x y (?? int32?) 
+         ((bop) (expr) (expr))
+         ((uop) (expr)))]
+  [bop (choose bvadd bvsub bvand bvor bvxor bvshl bvlshr bvashr)]
+  [uop (choose bvneg bvnot)])
+
+(define (bvmid-fast lo hi)
+  (fast-int32 lo hi #:depth 2))
+
+(define (bvmid-and? lo hi)
+  (equal? (fast-int32 l h #:depth 1) (fast-int32 l h #:depth 1)))
+
+(define (check-sqrt impl n)
+  (assume (bvsle (int32 0) n))
+  (define √n (impl l)) 
+  (define √n+1 (bvadd √n (int32 1)))
+  (assert (bvule (bvmul √n √n) n))
+  (assert (bvult n (bvmul √n+1 √n+1))))
+
+(define (check-mid-slow impl lo hi)        
+  (assume (bvsle (int32 0) lo))                  
+  (assume (bvsle lo hi))
+  (assert
+   (equal?
+    (bitvector->integer (impl lo hi))
+    (quotient (+ (bitvector->integer lo) (bitvector->integer hi)) 2))))
+
+(define-demo check-mid-demo
+  (demo (check-mid bvmid (int32 0) (int32 0)))
+  (demo (check-mid bvmid (int32 0) (int32 1)))
+  (demo (check-mid bvmid (int32 0) (int32 2)))
+  (demo (check-mid bvmid (int32 10) (int32 10000))))
+
+(define-demo verify-demo  
+  (define cex (time (verify (check-mid bvmid l h))))
+  (demo cex)
+  (define cl (evaluate l cex))
+  (define ch (evaluate h cex))
+  (demo cl)
+  (demo ch)
+  (demo (bvmid cl ch))
+  (demo (check-mid bvmid cl ch))
+  (demo (verify (check-mid bvmid-no-overflow l h))))
+
+(define-demo synthesize-demo
+  (define sol
+    (time
+     (synthesize
+      #:forall (list l h)
+      #:guarantee (check-mid bvmid-fast l h))))
+  (demo (dict-count (model sol)))
+  (demo sol)
+  (demo (print-forms sol)))
+
+(define-demo solve-demo
+  (define (bvmid-fast lo hi)
+    (bvlshr (bvadd hi lo) (bv #x00000001 32)))
+  (demo
+   (print-forms 
+    (time
+     (synthesize
+      #:forall (list l h)
+      #:guarantee
+      (begin
+        (assume (not (equal? l h)))
+        (assume (bvsle (int32 0) l))
+        (assume (bvsle l h))
+        (assert
+         (<=> (bvmid-and? l h)
+              (equal? (bvand l h) (bvmid-fast l h))))))))))
+
+(define-demo slowdown-demo
+  (demo (time (verify (check-mid bvmid l h))))
+  (demo (time (verify (check-mid-slow bvmid l h))))
+  (demo (time (verify (check-mid bvmid-no-overflow l h))))
+  (demo (with-deep-time-limit 10 (verify (check-mid-slow bvmid-no-overflow l h)))))
+
+(define-demo current-bitwidth-64-demo
+  (parameterize ([current-bitwidth 64])
+    (demo (time (verify (check-mid-slow bvmid l h))))
+    (demo (time (verify (check-mid-slow bvmid-no-overflow l h))))))
+
+(define-demo current-bitwidth-32-demo
+  (parameterize ([current-bitwidth 32])
+    (demo (time (verify (check-mid-slow bvmid l h))))
+    (demo (time (verify (check-mid-slow bvmid-no-overflow l h))))))
+
+(define-demo solver-options-demo
+  (demo (current-solver (z3 #:logic 'QF_BV)))
+  (demo (time (verify (check-mid bvmid l h))))
+  (demo (time (verify (check-mid-slow bvmid l h))))
+  (current-solver (z3)))
+
+(define-demo infinite-loop-demo
+  (define (bvsqrt n)
+    (cond
+      [(bvult n (int32 2)) n]
+      [else
+       (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+       (define s1 (bvadd s0 (int32 1)))
+       (if (bvugt (bvmul s1 s1) n) s0 s1)]))
+
+  (demo (bvsqrt (int32 3)))
+  (demo (bvsqrt (int32 4)))
+  (demo (bvsqrt (int32 15)))
+  (demo (bvsqrt (int32 16)))
+  (demo (with-terms
+          (with-deep-time-limit 10 (bvsqrt l)))))
+
+(define-demo sound-finitization-demo
+  (define fuel (make-parameter 5))
+  
+  (define-syntax-rule
+    (define-bounded (id param ...) body ...)
+    (define (id param ...)
+      (assert (> (fuel) 0) "Out of fuel") ; <--- no false negatives
+      (parameterize ([fuel (sub1 (fuel))])
+        body ...)))
+
+  (define-bounded (bvsqrt n)
+    (cond
+      [(bvult n (int32 2)) n]
+      [else
+       (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+       (define s1 (bvadd s0 (int32 1)))
+       (if (bvugt (bvmul s1 s1) n) s0 s1)]))
+
+  (demo (time (verify (check-sqrt bvsqrt l))))
+  (demo (fuel 16))
+  (demo (time (verify (check-sqrt bvsqrt l)))))
+
+(define-demo complete-finitization-demo
+  (define fuel (make-parameter 5))
+  
+  (define-syntax-rule
+    (define-bounded (id param ...) body ...)
+    (define (id param ...)
+      (assume (> (fuel) 0) "Out of fuel") ; <--- no false positives
+      (parameterize ([fuel (sub1 (fuel))])
+        body ...)))
+
+  (define-bounded (bvsqrt n)
+    (cond
+      [(bvult n (int32 2)) n]
+      [else
+       (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+       (define s1 (bvadd s0 (int32 1)))
+       (if (bvugt (bvmul s1 s1) n) s0 s1)]))
+
+  (demo (time (verify (check-sqrt bvsqrt l))))
+  (demo (fuel 16))
+  (demo (time (verify (check-sqrt bvsqrt l)))))
+
+(module+ main
+  (check-mid-demo)
+  (verify-demo)
+  (synthesize-demo)
+  (solve-demo)
+  (slowdown-demo)
+  (current-bitwidth-64-demo)
+  (current-bitwidth-32-demo)
+  (solver-options-demo)
+  (infinite-loop-demo)
+  (sound-finitization-demo)
+  (complete-finitization-demo))

rosette/guide/scribble/essentials/essentials-log.txt

@@ -9,7 +9,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "b"))))
+  (c values c (0 (u . "b\n"))))
  #""
  #"")
 ((boolean? b) ((3) 0 () 0 () () (q values #t)) #"" #"")
@@ -23,7 +23,7 @@
   0
   ()
   ()
-  (c values c (v! (0 (u . "b")) 1)))
+  (c values c (0 (u . "(vector b 1)\n"))))
  #""
  #"")
 ((not b)
@@ -35,7 +35,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(! b)"))))
+  (c values c (0 (u . "(! b)\n"))))
  #""
  #"")
 ((boolean? (not b)) ((3) 0 () 0 () () (q values #t)) #"" #"")
@@ -58,7 +58,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(= y$0 y$1)"))))
+  (c values c (0 (u . "(= y$1 y$2)\n"))))
  #""
  #"")
 ((define (yet-another-x) (define-symbolic x boolean?) x)
@@ -74,13 +74,16 @@
   0
   ()
   ()
-  (c values c (0 (u . "(<=> x x)"))))
+  (c values c (0 (u . "(<=> x x)\n"))))
  #""
  #"")
 ((assert #t) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert #f) ((3) 0 () 0 () () (q exn "assert: failed")) #"" #"")
+((assert #f) ((3) 0 () 0 () () (q exn "[assert] failed")) #"" #"")
+((vc-asserts (vc)) ((3) 0 () 0 () () (q values #f)) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc-asserts (vc)) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((assert (not b)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
+((vc-asserts (vc))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -89,107 +92,18 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "(! b)")) q #f)))
+  (c values c (0 (u . "(! b)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts) ((3) 0 () 0 () () (q values ())) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (poly x) (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (factored x) (* x (+ x 1) (+ x 2) (+ x 2)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (same p f x) (assert (= (p x) (f x))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((same poly factored 0) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((same poly factored -1) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((same poly factored -2) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-symbolic i integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define cex (verify (same poly factored i)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((evaluate i cex) ((3) 0 () 0 () () (q values -6)) #"" #"")
-((poly -6) ((3) 0 () 0 () () (q values 360)) #"" #"")
-((factored -6) ((3) 0 () 0 () () (q values 480)) #"" #"")
-((same poly factored -6) ((3) 0 () 0 () () (q exn "assert: failed")) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((require (only-in racket/draw read-bitmap))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((require rosette/query/debug) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (poly x) (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define/debug (factored x) (* x (+ x 1) (+ x 2) (+ x 2)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (same p f x) (assert (= (p x) (f x))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define ucore (debug (integer?) (same poly factored -6)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((require rosette/lib/synthax) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (poly x) (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (factored x) (* (+ x (??)) (+ x 1) (+ x (??)) (+ x (??))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (same p f x) (assert (= (p x) (f x))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define-symbolic i integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define binding
-   (synthesize #:forall (list i) #:guarantee (same poly factored i)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-('(define (factored x) (* (+ x 0) (+ x 1) (+ x 2) (+ x 3)))
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q values (define (factored x) (* (+ x 0) (+ x 1) (+ x 2) (+ x 3)))))
- #""
- #"")
-((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define sol
-   (solve
-    (begin
-      (assert (not (= x y)))
-      (assert (< (abs x) 10))
-      (assert (< (abs y) 10))
-      (assert (not (= (poly x) 0)))
-      (assert (= (poly x) (poly y))))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((evaluate x sol) ((3) 0 () 0 () () (q values 1)) #"" #"")
-((evaluate y sol) ((3) 0 () 0 () () (q values -4)) #"" #"")
-((evaluate (poly x) sol) ((3) 0 () 0 () () (q values 24)) #"" #"")
-((evaluate (poly y) sol) ((3) 0 () 0 () () (q values 24)) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-symbolic x integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((current-bitwidth 5) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((solve (begin (assert (= x 64)) (assert (= x 0))))
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume #t) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc-assumes (vc)) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((assume #f) ((3) 0 () 0 () () (q exn "[assume] failed")) #"" #"")
+((vc-assumes (vc)) ((3) 0 () 0 () () (q values #f)) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic i j integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume (> j 0)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc-assumes (vc))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -198,10 +112,11 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0])"))))
+  (c values c (0 (u . "(< 0 j)\n"))))
  #""
  #"")
-((verify (assert (not (and (= x 64) (= x 0)))))
+((assert (< (- i j) i)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc-asserts (vc))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -210,11 +125,10 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0])"))))
+  (c values c (0 (u . "(|| (! (< 0 j)) (< (+ i (- j)) i))\n"))))
  #""
  #"")
-((current-bitwidth #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((solve (begin (assert (= x 64)) (assert (= x 0))))
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -223,10 +137,18 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(vc (< 0 j) (|| (! (< 0 j)) (< (+ i (- j)) i)))\n"))))
  #""
  #"")
-((verify (assert (not (and (= x 64) (= x 0)))))
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define int32? (bitvector 32)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (int32 i) (bv i int32?))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((int32? 1) ((3) 0 () 0 () () (q values #f)) #"" #"")
+((int32? (int32 1)) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((int32 1)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -235,14 +157,47 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(bv #x00000001 32)\n"))))
  #""
  #"")
-((define-symbolic x integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((letrec ((adder
-           (lambda (vs n)
-             (if (null? vs) (list) (cons (+ (car vs) n) (adder (cdr vs) n))))))
-   (adder '(1 2 3) x))
+((define (bvmid lo hi) (bvsdiv (bvadd lo hi) (int32 2)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (check-mid impl lo hi)
+   (assume (bvsle (int32 0) lo))
+   (assume (bvsle lo hi))
+   (define mi (impl lo hi))
+   (define diff (bvsub (bvsub hi mi) (bvsub mi lo)))
+   (assert (bvsle lo mi))
+   (assert (bvsle mi hi))
+   (assert (bvsle (int32 0) diff))
+   (assert (bvsle diff (int32 1))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((check-mid bvmid (int32 0) (int32 0))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((check-mid bvmid (int32 0) (int32 1))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((check-mid bvmid (int32 0) (int32 2))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((check-mid bvmid (int32 10) (int32 10000))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic l h int32?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define cex (verify (check-mid bvmid l h)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(cex
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -254,6 +209,579 @@
   (c
    values
    c
-   (c (0 (u . "(+ 1 x)")) c (0 (u . "(+ 2 x)")) c (0 (u . "(+ 3 x)")))))
+   (0 (u . "(model\n [l (bv #x394f0402 32)]\n [h (bv #x529e7c00 32)])\n"))))
  #""
  #"")
+((define cl (evaluate l cex)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define ch (evaluate h cex)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((list cl ch)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list (bv #x394f0402 32) (bv #x529e7c00 32))\n"))))
+ #""
+ #"")
+((define il (bitvector->integer cl))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define ih (bitvector->integer ch))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((list il ih)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'(961479682 1386118144)\n"))))
+ #""
+ #"")
+((define m (bvmid cl ch)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(m
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #xc5f6c001 32)\n"))))
+ #""
+ #"")
+((bitvector->integer m) ((3) 0 () 0 () () (q values -973684735)) #"" #"")
+((quotient (+ il ih) 2) ((3) 0 () 0 () () (q values 1173798913)) #"" #"")
+((int32 (quotient (+ il ih) 2))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x45f6c001 32)\n"))))
+ #""
+ #"")
+((check-mid bvmid cl ch) ((3) 0 () 0 () () (q exn "[assert] failed")) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((bvadd cl ch)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x8bed8002 32)\n"))))
+ #""
+ #"")
+((bitvector->integer (bvadd cl ch))
+ ((3) 0 () 0 () () (q values -1947369470))
+ #""
+ #"")
+((+ il ih) ((3) 0 () 0 () () (q values 2347597826)) #"" #"")
+((- (expt 2 31) 1) ((3) 0 () 0 () () (q values 2147483647)) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (bvmid-no-overflow lo hi) (bvadd lo (bvsdiv (bvsub hi lo) (int32 2))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((verify (check-mid bvmid-no-overflow l h))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((require rosette/lib/synthax) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-grammar
+  (fast-int32 x y)
+  (expr (choose x y (?? int32?) ((bop) (expr) (expr)) ((uop) (expr))))
+  (bop (choose bvadd bvsub bvand bvor bvxor bvshl bvlshr bvashr))
+  (uop (choose bvneg bvnot)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/essentials/bvmid bvmid-fast))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/util/demo print-forms-alt))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define sol
+   (synthesize #:forall (list l h) #:guarantee (check-mid bvmid-fast l h)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(sol
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(model\n [0$choose:bvmid:37:9$expr:bvmid:37:3$fast-int32:bvmid:45:3 #f]\n [1$choose:bvmid:37:9$expr:bvmid:37:3$fast-int32:bvmid:45:3 #f]\n [2$choose:bvmid:37:9$expr:bvmid:37:3$fast-int32:bvmid:45:3 #f]\n [3$choose:bvmid:37:9$expr:bvmid:37:3$fast-int32:bvmid:45:3 #t]\n ...)\n\n"))))
+ #""
+ #"")
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvmid-fast lo hi) (bvlshr (bvadd hi lo) (bv #x00000001 32)))\n"
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (bvmid-fast lo hi) (bvlshr (bvadd hi lo) (bv 1 32)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define sol
+   (solve
+    (begin
+      (assume (not (equal? l h)))
+      (assume (bvsle (int32 0) l))
+      (assume (bvsle l h))
+      (assert (equal? (bvand l h) (bvmid-fast l h))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(sol
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x3f761e94 32)]\n [h (bv #x3f761e95 32)])\n"))))
+ #""
+ #"")
+((evaluate (bvand l h) sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x3f761e94 32)\n"))))
+ #""
+ #"")
+((evaluate (bvmid-fast l h) sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x3f761e94 32)\n"))))
+ #""
+ #"")
+((define (bvmid-and? lo hi) #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((void) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (check-mid-slow impl lo hi)
+   (assume (bvsle (int32 0) lo))
+   (assume (bvsle lo hi))
+   (assert
+    (equal?
+     (bitvector->integer (impl lo hi))
+     (quotient (+ (bitvector->integer lo) (bitvector->integer hi)) 2))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in racket error))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((time (verify (check-mid bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x394f0402 32)]\n [h (bv #x529e7c00 32)])\n"))))
+ #"cpu time: 0 real time: 38 gc time: 0\n"
+ #"")
+((time (verify (check-mid-slow bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x2faef9a1 32)]\n [h (bv #x5eefb8dd 32)])\n"))))
+ #"cpu time: 1 real time: 172 gc time: 0\n"
+ #"")
+((time (verify (check-mid bvmid-no-overflow l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #"cpu time: 0 real time: 160 gc time: 0\n"
+ #"")
+((error 'call-with-deep-time-limit "out of time")
+ ((3) 0 () 0 () () (q exn "call-with-deep-time-limit: out of time"))
+ #""
+ #"")
+((current-bitwidth) ((3) 0 () 0 () () (q values #f)) #"" #"")
+((current-bitwidth 64) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((time (verify (check-mid-slow bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x00000001 32)]\n [h (bv #x7fffffff 32)])\n"))))
+ #"cpu time: 0 real time: 23 gc time: 0\n"
+ #"")
+((time (verify (check-mid-slow bvmid-no-overflow l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #"cpu time: 0 real time: 159 gc time: 0\n"
+ #"")
+((current-bitwidth 32) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((time (verify (check-mid-slow bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #"cpu time: 0 real time: 0 gc time: 0\n"
+ #"")
+((time (verify (check-mid-slow bvmid-no-overflow l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x71979fa3 32)]\n [h (bv #x76b91b88 32)])\n"))))
+ #"cpu time: 1 real time: 152 gc time: 0\n"
+ #"")
+((current-bitwidth 512) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((time (verify (check-mid-slow bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x70000006 32)]\n [h (bv #x73fffffa 32)])\n"))))
+ #"cpu time: 1 real time: 385 gc time: 0\n"
+ #"")
+((time (verify (check-mid-slow bvmid-no-overflow l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #"cpu time: 0 real time: 430 gc time: 0\n"
+ #"")
+((current-bitwidth #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((require rosette/solver/smt/z3)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((current-solver (z3 #:logic 'QF_BV))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((time (verify (check-mid bvmid l h)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(model\n [l (bv #x394f0402 32)]\n [h (bv #x529e7c00 32)])\n"))))
+ #"cpu time: 3 real time: 33 gc time: 0\n"
+ #"")
+((time (verify (check-mid-slow bvmid l h)))
+ ((3)
+  0
+  ()
+  0
+  ()
+  ()
+  (q
+   exn
+   "read-solution: unrecognized solver output: (error line 68 column 19: Invalid function definition: unknown sort 'Int')"))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((current-solver (z3)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (bvsqrt n)
+   (cond
+    ((bvult n (int32 2)) n)
+    (else
+     (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+     (define s1 (bvadd s0 (int32 1)))
+     (if (bvugt (bvmul s1 s1) n) s0 s1))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((bvsqrt (int32 3))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x00000001 32)\n"))))
+ #""
+ #"")
+((bvsqrt (int32 4))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x00000002 32)\n"))))
+ #""
+ #"")
+((bvsqrt (int32 15))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x00000003 32)\n"))))
+ #""
+ #"")
+((bvsqrt (int32 16))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bv #x00000004 32)\n"))))
+ #""
+ #"")
+((error 'call-with-deep-time-limit "out of time")
+ ((3) 0 () 0 () () (q exn "call-with-deep-time-limit: out of time"))
+ #""
+ #"")
+((define n0 l) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(n0
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "l\n"))))
+ #""
+ #"")
+((define n1 (bvlshr n0 (int32 2)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(n1
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(bvlshr l (bv #x00000002 32))\n"))))
+ #""
+ #"")
+((define n2 (bvlshr n1 (int32 2)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(n2
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(bvlshr (bvlshr l (bv #x00000002 32)) (bv #x00000002 32))\n"))))
+ #""
+ #"")
+((define n3 (bvlshr n2 (int32 2)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(n3
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(bvlshr\n (bvlshr (bvlshr l (bv #x00000002 32)) (bv #x00000002 32))\n (bv #x00000002 32))\n\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((require (only-in racket make-parameter parameterize))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define fuel (make-parameter 5))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-syntax-rule
+  (define-bounded (id param ...) body ...)
+  (define (id param ...)
+    (assert (> (fuel) 0) "Out of fuel.")
+    (parameterize ((fuel (sub1 (fuel)))) body ...)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-bounded
+  (bvsqrt n)
+  (cond
+   ((bvult n (int32 2)) n)
+   (else
+    (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+    (define s1 (bvadd s0 (int32 1)))
+    (if (bvugt (bvmul s1 s1) n) s0 s1))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (check-sqrt impl n)
+   (assume (bvsle (int32 0) n))
+   (define √n (impl l))
+   (define √n+1 (bvadd √n (int32 1)))
+   (assert (bvule (bvmul √n √n) n))
+   (assert (bvult n (bvmul √n+1 √n+1))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define cex (time (verify (check-sqrt bvsqrt l))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #"cpu time: 4 real time: 1143 gc time: 0\n"
+ #"")
+((bvsqrt (evaluate l cex))
+ ((3) 0 () 0 () () (q exn "[assert] Out of fuel."))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((fuel 16) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((time (verify (check-sqrt bvsqrt l)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #"cpu time: 4 real time: 67938 gc time: 0\n"
+ #"")

rosette/guide/scribble/essentials/essentials.scrbl

@@ -1,17 +1,21 @@
 #lang scribble/manual
 
-@(require (for-label racket)
-          (for-label  
-           rosette/base/form/define (only-in rosette/base/core/safe assert)
-           rosette/query/query (only-in rosette asserts clear-asserts!)
-           (only-in rosette/base/base bv?)
-           (except-in rosette/query/debug assert) rosette/query/eval
-           (only-in rosette/lib/synthax ?? print-forms) rosette/lib/render))
+@(require (for-label
+           racket
+           (only-in racket/sandbox with-deep-time-limit)
+           rosette/base/form/define
+           rosette/query/query
+           rosette/solver/solution
+           (only-in rosette/base/base
+                    assert assume vc vc-asserts vc-assumes clear-vc!
+                    bv? bitvector
+                    bvsdiv bvadd bvsle bvsub bvand
+                    bvor bvxor bvshl bvlshr bvashr
+                    bvnot bvneg)
+           rosette/lib/synthax))
 
-@(require racket/sandbox  racket/runtime-path  scribble/core
-          scribble/eval scribble/html-properties ;scriblib/footnote 
-          (only-in racket [unsyntax racket/unsyntax])
-          (only-in racket/draw read-bitmap))
+@(require racket/sandbox racket/runtime-path scribble/core scribble/racket
+          scribble/example scribble/html-properties scriblib/footnote)
 
 @(require (only-in "../refs.scrbl" ~cite rosette:onward13 rosette:pldi14)
           "../util/lifted.rkt")
@@ -21,37 +25,22 @@
 
 @(define (symbolic s) @racketresultfont[s]) 
 
-@(define seen '())
-@(define (footnote . xs)
-   (define ord (add1 (length seen)))
-   (define mark (superscript (format "~a" ord)))
-   (define t (format "footnote~a" ord))
-   (set! seen (cons (apply elemtag t mark xs) seen))
-   (elemref t mark))
-@(define (footnote-part)
-   (let ([ts (reverse seen)])
-     (if (null? ts)
-         null
-         (cons (para #:style (style #f (list (attributes '((class . "footnoteblock")))))
-                     (car ts))
-               (map para (cdr ts))))))
-   
-@;(define-footnote footnote footnote-part)
+@(define-footnote footnote footnote-part)
 
 @title[#:tag "ch:essentials"]{Rosette Essentials}
 
 Rosette adds to Racket a collection of solver-aided facilities.
 These facilities enable programmers to conveniently access a constraint solver 
-that can answer interesting questions about program behaviors.  They are based on three 
-key concepts: @emph{symbolic values}, @emph{assertions} and @emph{queries}. 
-We use assertions to express desired program behaviors and symbolic values to 
+that can answer interesting questions about program behaviors.  They are based on four 
+key concepts: @emph{symbolic values}, @emph{assertions}, @emph{assumptions}, and @emph{queries}. 
+We use assertions and assumptions to express desired program behaviors and symbolic values to 
 formulate queries about these behaviors.
 
-This chapter illustrates the basics of solver-aided programming with a 
-few simple examples. More advanced tutorials, featuring extended examples, can be found 
+This chapter illustrates the basics of solver-aided programming.
+More advanced tutorials, featuring extended examples, can be found 
 in Section 2 of @~cite[rosette:onward13 rosette:pldi14].@footnote{Code examples in  
-these references are written in Rosette 1.0.
-While Rosette 2.0 is not backward compatible with Rosette 1.0,
+these references are written in earlier versions of Rosette.
+While Rosette 4 is not backward compatible with these versions,
 they share the same conceptual core.} 
 
 The following chapters describe the subset 
@@ -62,10 +51,10 @@ and @seclink["ch:programmer-defined-datatypes"]{programmer-defined}),
 
 @section[#:tag "sec:symbolic-values"]{Symbolic Values}
 
-The Rosette language includes two kinds of values: concrete and symbolic.  Concrete values are plain Racket values (@racket[#t], @racket[#f], @racket[0], @racket[1], etc.), and Rosette programs that operate only on concrete values behave just like Racket programs.  Accessing the solver-aided features of Rosette---such as code synthesis or verification---requires the use of symbolic values.
+The Rosette language includes two kinds of values: concrete and symbolic.  Concrete values are plain Racket values (@racket[#t], @racket[#f], @racket[0], @racket[1], etc.), and Rosette programs that operate only on concrete values behave like Racket programs.  Accessing the solver-aided features of Rosette---such as code synthesis or verification---requires the use of symbolic values.
 
 @deftech[#:key "symbolic constant"]{Symbolic constants} are the simplest kind of symbolic value.  They can be created using the @racket[define-symbolic] form:
-@def+int[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define-symbolic b boolean?)
 b]
 This generates a fresh symbolic constant of type boolean and binds it to the variable @racket[b].
@@ -73,7 +62,7 @@ This generates a fresh symbolic constant of type boolean and binds it to the var
 You can think of a symbolic constant as a placeholder for a concrete constant of the same type. As we will see shortly, the solver, once called, determines which concrete value a given symbolic constant represents:  it will tell us whether the constant @symbolic{b} is @racket[#t] or @racket[#f], depending on what question we ask about the behavior of a program (or a procedure) applied to @symbolic{b}.
 
 Symbolic values, including constants, can be used just like concrete values of the same type.  They can be stored in data structures or passed to procedures to obtain other values, either concrete or symbolic:
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (boolean? b)     
 (integer? b)
 (vector b 1)
@@ -83,17 +72,19 @@ In our example, all but the fourth expression produce concrete values.  The four
 
 
 Rosette provides one more construct for creating symbolic constants besides @racket[define-symbolic]:
-@def+int[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (define-symbolic* n integer?)]
 The two constructs differ in how they bind variables to constants when evaluated more than once.
 The @racket[define-symbolic] form binds the variable to the same (unique) constant every time it is evaluated. The @racket[define-symbolic*] form, in contrast, creates a stream of (unique) constants, binding the variable to the next constant from its stream whenever the form is evaluated. The following example illustrates the difference:
-@defs+int[#:eval rosette-eval
-((define (static) 
-  (define-symbolic x boolean?) (code:comment "creates the same constant when evaluated")
-  x)
+@examples[#:eval rosette-eval #:label #f
+(eval:no-prompt
+ (define (static) 
+  (define-symbolic x boolean?)  (code:comment "Creates the same constant when evaluated.")
+  x))
 
-(define (dynamic) 
-  (define-symbolic* y integer?) (code:comment "creates a different constant when evaluated")
+(eval:no-prompt
+ (define (dynamic) 
+  (define-symbolic* y integer?) (code:comment "Creates a fresh constant when evaluated.")
   y))
 
 (eq? (static) (static))
@@ -101,221 +92,444 @@ The @racket[define-symbolic] form binds the variable to the same (unique) consta
 
 Printed constant names, such as @symbolic{x} or @symbolic{b}, are just comments.  Two constants created by evaluating two distinct @racket[define-symbolic] (or, @racket[define-symbolic*]) forms are distinct, even if they have the same printed name.  They may still represent the same concrete value, but that is determined by the solver:
 
-@def+int[#:eval rosette-eval
-(define (yet-another-x) 
+@examples[#:eval rosette-eval #:label #f
+(eval:no-prompt
+ (define (yet-another-x) 
   (define-symbolic x boolean?) 
-  x)
+  x))
 
-; Produces a boolean expression whose meaning is 'true' if and only if the 
-; constant returned by (static) and the constant returned by (yet-another-x)
-; have the same concrete interpretation.
 (eq? (static) (yet-another-x))]
 
 
-@section[#:tag "sec:asserts"]{Assertions}
 
-Like many other languages, Rosette provides a construct for expressing @emph{assertions}---important properties of programs that are checked in every execution.  Rosette assertions work just like Java or Racket assertions when given a concrete value:  if the value is false, the execution terminates with a runtime error.  Otherwise, the execution proceeds normally.  
-@interaction[#:eval rosette-eval
+@section[#:tag "sec:asserts"]{Assertions and Assumptions}
+
+Like many languages, Rosette provides a construct for expressing @emph{assertions}---important properties of programs that are checked in every execution.  Rosette assertions work just like Java or Racket assertions when given a concrete value:  if the value is false, the execution terminates with a runtime exception.  Otherwise, the execution proceeds normally.  
+@examples[#:eval rosette-eval #:label #f
 (assert #t) 
-(assert #f)]
+(eval:error (assert #f))]
 
-When given a symbolic boolean value, however, a Rosette assertion has no immediate effect.  Instead, its effect (whether it passes or fails) is eventually determined by the solver.
-@interaction[#:eval rosette-eval
-(code:comment "add (not b) to the stack of assertions to be solved")
-(assert (not b))
-(code:comment "retrieve the assertion store")
-(asserts)
-(code:comment "clear the assertion store")
-(clear-asserts!)
-(asserts)]
+When given a symbolic boolean value, however, a Rosette assertion has no immediate effect.  Instead, the value is accumulated in the current @tech{verification condition} (VC), and the assertion's effect (whether it passes or fails) is eventually determined by the solver.
 
-@(rosette-eval '(clear-asserts!))
+@examples[#:eval rosette-eval #:label #f
+(code:line (vc-asserts (vc)) (code:comment "We asserted #f above, so the current VC reflects that."))
+(code:line (clear-vc!)       (code:comment "Clear the current VC."))
+(vc-asserts (vc))
+(code:line (assert (not b))  (code:comment "Add the assertion (not b) to the VC."))
+(vc-asserts (vc))
+(clear-vc!)]
+
+Assertions express properties that a program must satisfy on all @emph{legal} inputs. In Rosette, as in other solver-aided frameworks, we use @emph{assumptions} to describe which inputs are legal. If a program violates an assertion on a legal input, we blame the program. But if it violates an assertion on an illegal input, we blame the caller. In other words, a program is considered incorrect only when it violates an assertion on a legal input.
+
+Assumptions behave analogously to assertions on both concrete and symbolic values. In the concrete case, assuming @racket[#f] aborts the execution with a runtime exception, and assuming a true value is equivalent to calling @racket[(void)]. In the symbolic case, the assumed value is accumulated in the current VC.
+
+@examples[#:eval rosette-eval #:label #f
+(assume #t)
+(vc-assumes (vc))
+(eval:alts
+ (code:line (assume #f)         (code:comment "Assuming #f aborts the execution with an exception."))
+ (eval:error (assume #f)))
+(vc-assumes (vc))
+(clear-vc!)
+(define-symbolic i j integer?)
+(code:line (assume (> j 0))     (code:comment "Add the assumption (> j 0) to the VC."))
+(vc-assumes (vc))
+(assert (< (- i j) i))
+(code:line (vc-asserts (vc))    (code:comment "The assertions must hold when the assumptions hold."))
+(code:line (vc)                 (code:comment "VC tracks the assumptions and the assertions."))]
+
+@(rosette-eval '(clear-vc!))
 
 @section[#:tag "sec:queries"]{Solver-Aided Queries}
 
-The solver reasons about asserted properties only when we ask a question about them---for example, "Does my program have an execution that violates an assertion?"  We pose such @emph{solver-aided queries} with the help of constructs explained in the remainder of this chapter.
+The solver reasons about assumed and asserted properties only when we ask a question about them---for example, ``Does my program have an execution that violates an assertion while satisfying all the assumptions?''  We pose such @emph{solver-aided queries} with the help of constructs explained in the remainder of this chapter.
 
-We will illustrate the queries on the following toy example, where the @racket[factored] polynomial is intended to behave just like @racket[poly] on all inputs:
-@defs+int[#:eval rosette-eval
-((define (poly x)
-  (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
+We will illustrate the queries on the following toy example. Suppose that we want to implement a
+procedure @racket[bvmid] that takes as input two non-negative 32-bit integers, @racket[lo] ≤ @racket[hi],
+and returns the midpoint of the interval [@racket[lo], @racket[hi]]. In C or Java, we would declare
+the inputs and output of @racket[bvmid] to be of type ``int''. In Rosette, we model finite precision
+(i.e., machine) integers as @seclink["sec:bitvectors"]{bitvectors} of length 32.
 
- (define (factored x)
-  (* x (+ x 1) (+ x 2) (+ x 2)))
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:comment "int32? is a shorthand for the type (bitvector 32).")
+(define int32? (bitvector 32))]
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:comment "int32 takes as input an integer literal and returns")
+(code:comment "the corresponding 32-bit bitvector value.")
+(define (int32 i)
+  (bv i int32?))]
+@examples[#:eval rosette-eval #:label #f 
+(code:line (int32? 1)         (code:comment "1 is not a 32-bit integer"))
+(code:line (int32? (int32 1)) (code:comment "but (int32 1) is."))
+(int32 1)]
 
- (define (same p f x)
-  (assert (= (p x) (f x)))))
+Bitvectors support the usual operations on machine integers, and we can use them to implement @racket[bvmid] as follows: 
 
-(code:comment "check zeros; all seems well ...")
-(same poly factored 0)
-(same poly factored -1)
-(same poly factored -2)]
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:comment "Returns the midpoint of the interval [lo, hi].") 
+(define (bvmid lo hi)  (code:comment "(lo + hi) / 2")            
+  (bvsdiv (bvadd lo hi) (int32 2)))]
+
+As the above implementation suggests, we intend the midpoint to be the mathematical
+integer @tt{mi = (lo + hi) / 2}, where @tt{/} stands for integer division. Assuming
+that @tt{0 ≤ lo ≤ hi}, the midpoint @tt{mi} is fully characterized by two properties:
+(1) @tt{lo ≤ mi ≤ hi} and (2) @tt{0 ≤ (hi - mi) - (mi - lo) ≤ 1}. We can use these
+properties to define a generic correctness specification for any implementation of
+@racket[bvmid] as follows: 
+
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:line
+(define (check-mid impl lo hi)     (code:comment "Assuming that")
+  (assume (bvsle (int32 0) lo))    (code:comment "0 ≤ lo and")             
+  (assume (bvsle lo hi))           (code:comment "lo ≤ hi,") 
+  (define mi (impl lo hi))         (code:comment "and letting mi = impl(lo, hi) and") 
+  (define diff                     (code:comment "diff = (hi - mi) - (mi - lo),")
+    (bvsub (bvsub hi mi)             
+           (bvsub mi lo)))         (code:comment "we require that")
+  (assert (bvsle lo mi))           (code:comment "lo ≤ mi,")
+  (assert (bvsle mi hi))           (code:comment "mi ≤ hi,")
+  (assert (bvsle (int32 0) diff))  (code:comment "0 ≤ diff, and")
+  (assert (bvsle diff (int32 1)))) (code:comment "diff ≤ 1."))]
+
+This is not the only way to specify the behavior of @racket[bvmid], and we will see an
+alternative specification later on. In general, there are many ways to describe what it
+means for a program to be correct, and often, these descriptions are partial: 
+they constrain some aspects of the implementation (e.g., the output is positive)
+without fully defining its behavior. In our example, @racket[check-mid] is a
+@emph{full functional correctness specification} in that it admits exactly one output value for @racket[(impl lo hi)], namely, @tt{(lo + hi) / 2}.
+
+Testing @racket[bvmid] against its specification on a few concrete legal inputs, we find
+that it triggers no assertion failures, as expected:
+
+@examples[#:eval rosette-eval #:label #f  
+ (check-mid bvmid (int32 0) (int32 0))
+ (check-mid bvmid (int32 0) (int32 1))
+ (check-mid bvmid (int32 0) (int32 2))
+ (check-mid bvmid (int32 10) (int32 10000)) ]
+
+But does it work correctly on @emph{all} legal inputs?  The answer, as we will see below, is ``no''.
+In fact, @racket[bvmid] reproduces  @hyperlink["https://en.wikipedia.org/wiki/Binary_search_algorithm#Implementation_issues"]{a famous bug}
+that lurked for years in widely used C and Java implementations of binary search.
        
 
 @subsection[#:tag "sec:verify"]{Verification}
 
-To verify that @racket[poly] and @racket[factored] behave identically, we could simply enumerate all k-bit integers and apply the @racket[same] check to each.  This naive approach to verification would, of course, be very slow for a large k---and impossible for infinite precision integers. A better approach is to delegate such checks to a constraint solver, which can search large input spaces more effectively.  In Rosette, this is done with the help of the @racket[verify] query:
-@interaction[#:eval rosette-eval
-(define-symbolic i integer?)
-(define cex (verify (same poly factored i)))] 
+How can we check if @racket[bvmid] satisfies its specification on all legal inputs? One approach is to enumerate all pairs of 32-bit integers with @racket[0 ≤ lo ≤ hi] and apply @racket[(check-mid bvmid hi lo)] to each. This approach is sound (it is guaranteed to find a bug if one exists), but a quick calculation shows that it is impractical even for our toy example: @racket[bvmid] has roughly 2.3 × 10@superscript{18} legal inputs. A better approach is to delegate such checks to a constraint solver, which can search  large input spaces much more effectively than naive enumeration.  In Rosette, this is done with the help of the @racket[verify] query:
 
-The @racket[(verify #, @var[expr])] form queries the solver for a @deftech{binding} from symbolic constants to concrete values that causes the evaluation of @var[expr] to fail when the bound symbolic constants are replaced with the corresponding concrete values. If such a binding exists, as it does in our case, it is called a @emph{counterexample}. 
+@examples[#:eval rosette-eval #:label #f  
+(eval:no-prompt (define-symbolic l h int32?))
+(define cex (verify (check-mid bvmid l h)))
+cex] 
+
+The @racket[(verify #, @var[expr])] form queries the solver for a @deftech{binding} from symbolic constants to concrete values that causes the evaluation of @var[expr] to violate an assertion, while satisfying all the assumptions, when the bound symbolic constants are replaced with the corresponding concrete values. If such a binding exists, as it does in our case, it is called a @emph{counterexample}. 
 
 Bindings are first-class values in Rosette, and they can be freely manipulated by programs.  We can also interpret any Rosette value with respect to a binding using the built-in @racket[evaluate] procedure:
-@interaction[#:eval rosette-eval
-(evaluate i cex)
-(poly -6)
-(factored -6)
-(same poly factored -6)]
-In our example, evaluating @racket[i] with respect to @racket[cex] reveals that @racket[poly] and @racket[factored] produce different results on the input -6 thus causing the assertion in the @racket[same] procedure to fail.
+@examples[#:eval rosette-eval #:label #f 
+(define cl (evaluate l cex))
+(define ch (evaluate h cex))
+(list cl ch)
+(code:comment "We can convert these values to integer? constants for debugging:")
+(define il (bitvector->integer cl))
+(define ih (bitvector->integer ch))
+(list il ih)
+(code:comment "Here is the computed midpoint:")
+(define m (bvmid cl ch))
+m
+(bitvector->integer m) 
+(code:comment "This is clearly wrong. We expect (il + ih) / 2 instead:")
+(quotient (+ il ih) 2)
+(code:comment "Expressed as a 32-bit integer, the correct answer is:")
+(int32 (quotient (+ il ih) 2))
+(code:comment "So, check-mid fails on (bvmid cl ch):")
+(eval:error (check-mid bvmid cl ch))]
+@(rosette-eval '(clear-vc!))
 
-@(rosette-eval '(clear-asserts!))
-@(rosette-eval '(require (only-in racket/draw read-bitmap)))
+In our example, evaluating @racket[l] and @racket[h] with respect to @racket[cex] reveals that @racket[bvmid] fails to return the correct midpoint value, thus causing the first assertion in the @racket[check-mid] procedure to fail. The bug is due to overflow:  
+the expression @racket[(bvadd lo hi)] in @racket[bvmid] produces a negative value in
+the 32-bit representation when the sum of
+@racket[lo] and @racket[hi] exceeds 2@\superscript{31}-1.
 
-@subsection[#:tag "sec:debug"]{Debugging}
+@examples[#:eval rosette-eval #:label #f 
+(bvadd cl ch)
+(bitvector->integer (bvadd cl ch))
+(+ il ih)
+(- (expt 2 31) 1)]
              
-Now that we have an input on which @racket[factored] differs from @racket[poly], the next step is to debug it, by figuring out which of its subexpressions are responsible for the fault.  Rosette provides a query for this as well.  To access it, we import the debugging facilities, mark @racket[factored] as a candidate for debugging, and issue a @racket[debug] query. 
+@(rosette-eval '(clear-vc!))
 
-First, save these definitions to a file:
-@racketblock[
-#, @elem{#}lang rosette
+A common  @hyperlink["https://en.wikipedia.org/wiki/Binary_search_algorithm#Implementation_issues"]{solution}
+to this problem is to calculate the midpoint as @tt{lo + ((hi - lo) / 2)}. It is easy to see that all intermediate values in this calculation are at most @racket[hi] when @racket[lo] and @racket[hi] are both non-negative, so no overflow can happen. We can also verify this with Rosette:
 
-(require rosette/query/debug rosette/lib/render)
+@examples[#:eval rosette-eval #:label #f 
+(eval:no-prompt
+ (define (bvmid-no-overflow lo hi)
+  (bvadd lo (bvsdiv (bvsub hi lo) (int32 2)))))
 
-(define (poly x)
-  (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
-
-(define/debug (factored x)       (code:comment "define/debug marks a procedure as part of")
-  (* x (+ x 1) (+ x 2) (+ x 2))) (code:comment "the code to be debugged")
- 
-(define (same p f x)
-  (assert (= (p x) (f x))))]
-
-Then call the debugger after loading the above definitions:
-@racketblock[
-#, @elem{>} (define ucore (debug [integer?] (same poly factored -6)))
-#, @elem{>} (render ucore) 
-#,(call-with-input-file (build-path root "pict.png") (lambda (in) (read-bitmap in 'png)))]
-
-@(rosette-eval '(require rosette/query/debug))
-@(rosette-eval '(define (poly x)
-       (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x))))
-@(rosette-eval '(define/debug (factored x)        
-       (* x (+ x 1) (+ x 2) (+ x 2))))
-@(rosette-eval '(define (same p f x)
-       (assert (= (p x) (f x)))))
-@(rosette-eval '(define ucore (debug [integer?] (same poly factored -6))))
-
-The @racket[(debug [#, @var[predicate]] #, @var[expr])] query takes as input an expression whose execution leads to an assertion failure, and one or more dynamic type predicates specifying which executed expressions should be treated as potentially faulty by the solver. That is, the predicates express the hypothesis that the failure is caused by an expression with one of the given types. Expressions that produce values of a different type are assumed to be correct.@footnote{For now, only primitive (@racket[boolean?], @racket[integer?], @racket[real?], and @racket[bv?]) types can be used in @racket[debug] forms.}
-
-The output of a @racket[debug] query is a minimal set of program expressions, called a @deftech[#:key "MUC"]{minimal unsatisfiable core}, that form an irreducible cause of the failure. Expressions outside of the core are irrelevant to the failure---there is no way to replace them with constants so that the resulting program satisfies the failing assertion. The failing assertion can only be satisfied if we are allowed to also replace one of the core expressions with a carefully chosen constant.  In general, a failing expression may have many different cores, but since every core highlights a buggy subexpression, examining one or two cores often leads to the root cause of the error.
-
-Like bindings, cores are first-class values. In our example, we simply visualize the core using the utility procedure @racket[render].@footnote{@racket[render] can only visualize cores for code that has been saved to a file.} The visualization reveals that the grayed-out subexpression @racket[(+ x 1)] is irrelevant to the failure of @racket[factored] on the input -6.  To repair this failure, we have to modify at least one of the remaining expressions, which are highlighted in red.  
+(verify (check-mid bvmid-no-overflow l h))]
 
 @subsection[#:tag "sec:synthesize"]{Synthesis}
 
-The solver can not only find failure-inducing inputs and localize faults, it can also synthesize repairs for buggy expressions.  To repair a program, we first replace each buggy expression with a syntactic "@deftech{hole}."  A program with holes is called a @deftech{sketch}.  The solver completes a sketch by filling its holes with expressions, in such a way that all assertions in the resulting program pass on all inputs.  
-
-The following code snippet shows the sketch for our buggy @racket[factored] procedure.  We obtained it by replacing the constants in the @seclink["sec:debug"]{minimal core} with @racket[(??)] holes, which are filled with numerical constants.@footnote{This simple replacement strategy is sufficient since we know that a factorization of an @var{n}-degree polynomial takes the form @tt{(* (+ x @var[c]@subscript{0}) ... (+ x @var[c]@subscript{@var{n}}))}, where @var[c]@subscript{@var{i}} is a constant.}
-@defs+int[#:eval rosette-eval
-((require rosette/lib/synthax) 
- 
- (define (poly x)
-  (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
-
- (define (factored x)        
-  (* (+ x (??)) (+ x 1) (+ x (??)) (+ x (??))))  
- 
- (define (same p f x)
-  (assert (= (p x) (f x)))))]
-
-The @racket[(??)] construct is imported from the @racket[rosette/lib/synthax] library, which also provides constructs for specifying more complex holes.  For example, you can specify a hole that is filled with an expression, drawn from a grammar you define.   
+The solution given in @racket[bvmid-no-overflow] avoids the overflow problem in @racket[bvmid] at the cost of performing an additional arithmetic operation. Both implementations also rely on signed division, which is slow and expensive compared to addition, subtraction, and bitwise operations. So our ideal implementation would be correct, small, and composed of only cheap arithmetic and bitwise operations. Does such an implementation exist?  To find out, we turn to Rosette's @racket[synthesize] query.
 
 
-We query the solver for a correct completion of our sketch as follows:
-@interaction[#:eval rosette-eval
-(code:comment "Call after saving the above definitions to a file:")                    
-(define-symbolic i integer?)
-(define binding 
-  (synthesize #:forall (list i)
-              #:guarantee (same poly factored i)))
-(eval:alts (print-forms binding) '(define (factored x) (* (+ x 0) (+ x 1) (+ x 2) (+ x 3))))]
-The @racket[(synthesize #:forall #, @var[input] #:guarantee #, @var[expr])] query uses the @var[input] form to specify a set of distinguished symbolic values, which are treated as inputs to the expression @var[expr]. The result, if any, is a binding for the remaining symbolic values, created by evaluating holes.  This binding guarantees successful evaluation of @var[expr] for @emph{all} possible bindings of the @var[input] values. Passing it to the @racket[print-forms] procedure yields a syntactic representation of the completed sketch.@footnote{@racket[print-forms] can only print the completion of a sketch that has been saved to a file.}
+The synthesis query uses the solver to search for a correct program in a space of candidate implementations defined by a syntactic @deftech{sketch}. A sketch is a program with @deftech[#:key "hole"]{holes}, which the solver fills with expressions drawn from a specified set of options. For example, @racket[(?? int32?)] stands for a hole that can be filled with any 32-bit integer constant, so the sketch @racket[(bvadd x (?? int32?))] represents all 2@superscript{32} programs that add a 32-bit constant to the variable @racket[x]. Rosette also lets you define richer holes that can be filled with expressions from a given grammar. For example, here is a grammar of all @racket[int32?] expressions that consist of cheap arithmetic and bitwise operations:
+
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:line
+ (require rosette/lib/synthax)     (code:comment "Require the sketching library."))
+(code:line
+ (define-grammar (fast-int32 x y)  (code:comment "Grammar of int32 expressions over two inputs:")
+   [expr
+    (choose x y (?? int32?)        (code:comment "<expr> := x | y | <32-bit integer constant> |")
+            ((bop) (expr) (expr))  (code:comment "          (<bop> <expr> <expr>) |")
+            ((uop) (expr)))]       (code:comment "          (<uop> <expr>)")
+   [bop
+    (choose bvadd bvsub bvand      (code:comment "<bop>  := bvadd  | bvsub | bvand |")
+            bvor bvxor bvshl       (code:comment "          bvor   | bvxor | bvshl |")
+            bvlshr bvashr)]        (code:comment "          bvlshr | bvashr")
+   [uop
+    (choose bvneg bvnot)])         (code:comment "<uop>  := bvneg | bvnot"))]
+
+Using this grammar, we can sketch a fast implementation of the midpoint calculation as follows:
+
+@examples[#:eval rosette-eval #:label #f #:no-prompt 
+(eval:alts
+  (define (bvmid-fast lo hi)
+    (fast-int32 lo hi #:depth 2))
+  (require (only-in rosette/guide/scribble/essentials/bvmid bvmid-fast)))]
+
+The above sketch describes the space of all expressions from the @racket[fast-int32] grammar that have parse trees of depth at most 2. The depth argument is optional. If ommitted, Rosette will use the value of the @racket[(current-grammar-depth)] parameter to bound the depth of the expressions drawn from the grammar.
+
+At this point, it is worth noting that holes and sketches are not fundamental concepts in Rosette. Instead, they are macros defined in terms of the core constructs we have already seen, symbolic constants and assertions. For example,  @racket[(?? int32?)] is syntactic sugar for @racket[(let () (define-symbolic #, @var[id] int32?) #, @var[id])], where @var[id] is an internally generated name. Similarly, @racket[(choose bvneg bvnot)] expands to @racket[(if (?? boolean?) bvneg bvnot)]. Finally, a grammar hole such as @racket[(fast-int32 lo hi #:depth 2)] inlines its productions @racket[#:depth] times to create a nested expression of the form @racket[(choose lo hi (?? int32?) ((choose bvadd ...) (choose ...) (choose ...)) ((choose bvneg bvnot) (choose ...)))]. Assigning concrete values to the symbolic constants generated by this expression has the effect of selecting a parse tree (of depth 2 in our example) from the hole's grammar. So, completing a sketch is a matter of finding a suitable binding for the symbolic constants generated by the holes.
+
+With this in mind, we can query the solver for a completion of the @racket[bvmid-fast] sketch (if any) that satisfies our correctness specification:
+@(rosette-eval '(require (only-in rosette/guide/scribble/util/demo print-forms-alt)))
+@examples[#:eval rosette-eval #:label #f
+(code:comment "Save the above definitions to a file before calling print-forms.")
+(define sol
+  (synthesize
+   #:forall    (list l h)
+   #:guarantee (check-mid bvmid-fast l h)))
+sol
+(eval:alts 
+(print-forms sol)
+(print-forms-alt sol))]
+
+The synthesis query takes the form @racket[(synthesize #:forall #, @var[input] #:guarantee #, @var[expr])], where @var[input] lists the symbolic constants that represent inputs to a sketched program, and @var[expr] gives the correctness specification for the sketch. The solver searches for a binding from the hole (i.e., non-@var[input]) constants to values such that @var[expr] satisfies its assertions on all legal @var[input]s. Passing this binding to @racket[print-forms] converts it to a syntactic representation of the completed sketch.@footnote{@racket[print-forms] works only on sketches that have been saved to disk.} In our example, the synthesized program implements the midpoint calculation using the logical shift operation, i.e., the midpoint between @racket[lo] and @racket[hi] is calculated as @tt{(lo + hi) >>@subscript{u} 1}.
+
+@(rosette-eval '(clear-vc!))
 
 @subsection[#:tag "sec:solve"]{Angelic Execution}
 
-Rosette supports one more solver-aided query, which we call "angelic execution." This query is the opposite of verification.  Given a program with symbolic values, it instructs the solver to find a binding for them that will cause the program to execute successfully---that is, without any assertion failures. 
+Rosette supports one more solver-aided query, which we call angelic execution. This query is the dual of verification.  Given a program with symbolic values, it instructs the solver to find a binding for them that will cause the program to execute normally---that is, without any assumption or assertion failures. 
+
+Angelic execution can be used to solve puzzles, to run incomplete code, or to ``invert'' a program, by searching for inputs that produce a desired output.  For example, we can ask the solver to search for two distinct legal inputs, @racket[l] and @racket[h], whose midpoint is the bitwise-and of their bits:
+@examples[#:eval rosette-eval #:label #f 
+(define (bvmid-fast lo hi)
+  (bvlshr (bvadd hi lo) (bv #x00000001 32)))
 
-Angelic execution can be used to solve puzzles, to run incomplete code, or to "invert" a program, by searching for inputs that produce a desired output.  For example, we can ask the solver to find two distinct input values, which are not zeros of the @racket[poly] function, but which @racket[poly] still maps to the same output: 
-@interaction[#:eval rosette-eval
-(define-symbolic x y integer?)
 (define sol 
-  (solve (begin (assert (not (= x y)))
-                (assert (< (abs x) 10))
-                (assert (< (abs y) 10))
-                (assert (not (= (poly x) 0)))
-                (assert (= (poly x) (poly y))))))
-(evaluate x sol)
-(evaluate y sol)
-(evaluate (poly x) sol)
-(evaluate (poly y) sol)]
+  (solve
+   (begin
+     (assume (not (equal? l h)))
+     (assume (bvsle (int32 0) l))
+     (assume (bvsle l h))
+     (assert (equal? (bvand l h) (bvmid-fast l h))))))
 
-You can find more examples of angelic execution and other solver-aided queries in the @hyperlink["https://github.com/emina/rosette/blob/master/sdsl/"]{@racket[sdsl]} folder of your Rosette distribution.
+sol
 
-@(rosette-eval '(clear-asserts!))
+(evaluate (bvand l h) sol)
+(evaluate (bvmid-fast l h) sol)]
+As a fun exercise that builds on this result, try using program synthesis to discover the condition, @racket[(bvmid-and? l h)], that is both necessary and sufficient to ensure that @racket[bvand] and @racket[bvmid-fast] produce the same value on all distinct legal inputs @racket[l] and @racket[r]. (Hint: you can reuse the @racket[fast-int32] grammar from the previous section.)
+
+@examples[#:eval rosette-eval #:label #f 
+(eval:no-prompt
+ (define (bvmid-and? lo hi)
+  #f (code:comment "<--- replace with your sketch\n")
+  ))
+
+(eval:alts
+(print-forms 
+ (synthesize
+  #:forall (list l h)
+  #:guarantee
+  (begin
+    (assume (not (equal? l h)))
+    (assume (bvsle (int32 0) l))
+    (assume (bvsle l h))
+    (assert
+     (<=> (bvmid-and? l h)
+          (equal? (bvand l h) (bvmid-fast l h)))))))
+  (void))]
+
+@(rosette-eval '(clear-vc!))
 
 @section[#:tag "sec:notes"]{Symbolic Reasoning}
 
-Rosette implements solver-aided queries by translating them to the input language of an SMT solver.
-This translation is performed using a given @tech["reasoning precision"], as specified
-by the @racket[current-bitwidth] parameter.  Setting @racket[current-bitwidth]
-to a positive integer @var{k} instructs Rosette to approximate both reals and integers with @var{k}-bit words.
-Setting it to @racket[#f] instructs Rosette to use infinite precision for real and integer operations.
+We conclude this chapter with a quick overview of common patterns and anti-patterns for programming in Rosette. For more details, see Chapters @seclink["ch:unsafe"]{8}--@seclink["ch:error-tracing"]{10}.
 
-The following snippet shows the effect of different @racket[current-bitwidth] settings on query behavior:
-@interaction[#:eval rosette-eval
-(define-symbolic x integer?)
-(current-bitwidth 5)  (code:comment "64 = 0 in the 5-bit representation")
-(solve (begin (assert (= x 64))
-              (assert (= x 0))))
-(verify (assert (not (and (= x 64) (= x 0))))) 
-(current-bitwidth #f) (code:comment "but no solutions exist under infinite-precision semantics")
-(solve (begin (assert (= x 64))
-              (assert (= x 0))))
-(verify (assert (not (and (= x 64) (= x 0)))))]
+@subsection{Mixing Theories}
 
-By default, @racket[current-bitwidth] is set to @racket[#f] to be consistent with Racket's
-infinite-precision semantics for integers and reals. Beware, however, that using @racket[#f] or a large @var{k}
-for @racket[current-bitwidth] may have a negative effect on solver performance.  In the worst case, using @racket[#f] can cause the underlying solver to run forever.@footnote{Technically, Rosette translates solver-aided queries to the theory of bitvectors when @racket[current-bitwidth] is set to an integer @var{k}. In particular, it uses @var{k}-bit bitvectors to represent integers and reals, with smaller bitvectors leading to better performance.  When @racket[current-bitwidth] is @racket[#f], Rosette uses the theories of integers and reals instead.  These theories work well for linear constraints, but reasoning about non-linear integer arithmetic is undecidable.}
+Rosette implements solver-aided queries by translating them to the input language of an SMT solver. By default, this translation respects types: a symbolic constant of type @racket[integer?] will be translated to an SMT constant of the same type, i.e., an infinite precision mathematical integer. These types determine which @emph{theories} the solver will need to use to solve a query. As a rule of thumb, the theory of bitvectors tends to elicit fastest solving times, and mixing theories can lead to severe performance degradation. For that reason, it is best to use the types from the same theory throughout your program (e.g., bitvectors).
 
-Non-termination can also be caused by passing symbolic values to recursive procedures.  In particular, the expression that determines whether a recursion (or a loop) terminates must be executed on concrete values.   
+To illustrate the impact of mixing theories, consider the following mixed-theory specification for our midpoint example:
 
-@interaction[
-(code:comment "while sandboxed evaluation of (ones x) times out,")
-(code:comment "normal evaluation would not terminate")
-(eval:alts (define-symbolic x integer?) (void))
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:line
+(define (check-mid-slow impl lo hi)      (code:comment "Assuming that")        
+  (assume (bvsle (int32 0) lo))          (code:comment "0 ≤ lo and")                  
+  (assume (bvsle lo hi))                 (code:comment "lo ≤ hi,")
+  (assert                                (code:comment "we require that")
+   (equal?                               
+    (bitvector->integer (impl lo hi))    (code:comment "⌈impl(lo, hi)⌉ = ")
+    (quotient                            (code:comment "(⌈lo⌉ + ⌈hi⌉) / 2, where")
+     (+ (bitvector->integer lo)          (code:comment "⌈e⌉ stands for the mathematical")
+        (bitvector->integer hi))         (code:comment "integer corresponding to the")
+     2))))                               (code:comment "32-bit integer e."))]
+
+This new specification uses both bitvectors and integers. Compared to @racket[check-mid], which uses only bitvectors, @racket[check-mid-slow] causes one of our verification queries to become an order of magnitude slower and the other to time out:
+
+@(rosette-eval '(require (only-in racket error)))
+
+@examples[#:eval rosette-eval #:label #f 
+(time (verify (check-mid bvmid l h)))
+(time (verify (check-mid-slow bvmid l h)))
+(time (verify (check-mid bvmid-no-overflow l h)))
 (eval:alts
-(letrec ([ones (lambda (n)
-                  (if (<= n 0)
-                      (list)
-                      (cons 1 (ones (- n 1)))))])
-  (printf "~a" (ones 3))
-  (printf "~a" (ones x)))
-(begin (printf "(1 1 1)")
-       (fprintf (current-error-port) "with-limit: out of time")))]
+(with-deep-time-limit 600 (code:comment "Timeout after 10 minutes ...")
+  (verify (check-mid-slow bvmid-no-overflow l h)))
+(eval:error (error 'call-with-deep-time-limit "out of time")))]
 
 
-It is, however, safe to apply recursive procedures to symbolic values if they are not used in termination checks.  
-@interaction[#:eval rosette-eval
-(define-symbolic x integer?)
-(letrec ([adder (lambda (vs n)
-                  (if (null? vs)
-                      (list)
-                      (cons (+ (car vs) n) (adder (cdr vs) n))))])
-  (adder '(1 2 3) x))]
+@subsection{Reasoning Precision}
+
+While slower than bitvectors, integers are more convenient to use for demos, prototyping, and interfacing with Racket. To bridge this gap, Rosette provides the option of approximating symbolic integers (and reals) as bitvectors of length @var{k}, by setting the @racket[current-bitwidth] parameter to @var{k}. With this setting, integers (and reals) are treated as infinite precision values during evaluation, but when solving queries, they are translated to bitvectors of length @var{k} for better performance. 
+
+For example, our slow midpoint queries become orders-of-magnitude faster when allowed to approximate integers with bitvectors:
+@examples[#:eval rosette-eval #:label #f 
+(code:comment "By default, current-bitwidth is set to #f, so Rosette translates")
+(code:comment "integer? values precisely, using the SMT theory of integers.")
+(current-bitwidth)
+(code:comment "After we set current-bitwidth to 64, integer? values in")
+(code:comment "check-mid-slow are translated to SMT bitvectors of length 64.")
+(current-bitwidth 64)
+(time (verify (check-mid-slow bvmid l h)))
+(time (verify (check-mid-slow bvmid-no-overflow l h)))]
+
+In this example, we have chosen @racket[current-bitwidth] carefully to ensure that the resulting approximation is both performant and sound---i.e., the approximate query returns a counterexample exactly when one would be returned by the corresponding integer query. But choosing the right bitwidth is difficult to do in general. If we underapproximate the number of bits that are needed to represent every integer value in a query, we lose soundness, and if we overapproximate it, we lose performance.
+
+For instance, when we re-run the slow midpoint queries with @racket[current-bitwidth] set to 32, the buggy query fails to produce a counterexample and the correct query returns a bogus counterexample.  Both results are correct for 32-bit machine integers but incorrect for (infinite-precision) mathematical integers:
+@examples[#:eval rosette-eval #:label #f 
+(code:comment "The bitwidth is too low, so we get ...")
+(current-bitwidth 32) 
+(code:comment "no counterexample to a buggy query, and")
+(time (verify (check-mid-slow bvmid l h)))
+(code:comment "a bogus counterexample to a correct query.")
+(time (verify (check-mid-slow bvmid-no-overflow l h)))]
+We can restore soundness by sacrificing performance and setting @racket[current-bitwidth] conservatively to a large value (e.g., 512). In our case, the queries are small so an order-of-magnitude slowdown is acceptable. For large queries, this would lead to timeouts:
+@examples[#:eval rosette-eval #:label #f 
+(code:comment "The bitwidth is too high, so we get a 3-10X slowdown.")
+(current-bitwidth 512) 
+(time (verify (check-mid-slow bvmid l h)))
+(time (verify (check-mid-slow bvmid-no-overflow l h)))]
+
+In practice, it is usually best to leave @racket[current-bitwidth] at its default setting (@racket[#f]), and limit the use of integers to code that will be evaluated concretely. This approach works especially well when the solver is configured to accept only bitvectors, so if any integers have made it into a query, the solver fails fast:
+@examples[#:eval rosette-eval #:label #f 
+(current-bitwidth #f)
+(require rosette/solver/smt/z3)
+(code:line (current-solver (z3 #:logic 'QF_BV))       (code:comment "Allow only bitvectors."))
+(code:line (time (verify (check-mid bvmid l h)))      (code:comment "Accepted."))
+(eval:alts
+(code:line (time (verify (check-mid-slow bvmid l h))) (code:comment "Rejected."))
+(eval:error (time (verify (check-mid-slow bvmid l h)))))]
+
+@(rosette-eval '(clear-vc!))
+@(rosette-eval '(current-solver (z3)))
+
+@subsection{Symbolic Evaluation}
+
+The process by which Rosette turns a query into an SMT constraint is called @deftech{symbolic evaluation}. At a high level, Rosette's symbolic evaluation works by executing @emph{all} paths through a program, and collecting all the assumptions and assertions on these paths into the current verification condition @racket[(vc)]. The resulting @racket[(vc)] is then translated to the SMT language and passed to the solver.  This evaluation model has two practical implications on writing performant and terminating Rosette code.
+
+First, if a program is slow or runs forever under standard (concrete) evaluation, it will perform at least as poorly under all-path (symbolic) evaluation. Second, if a program terminates quickly on all concrete inputs, it can still perform poorly or fail to terminate on symbolic inputs. So, extra care must be taken to ensure good performance and termination in the presence of symbolic values. 
+
+To illustrate, consider the procedure @racket[bvsqrt] for computing the @hyperlink["https://en.wikipedia.org/wiki/Integer_square_root#Using_bitwise_operations"]{integer square root} of non-negative 32-bit integers. This procedure terminates on all concrete values of @racket[n] but runs forever when given a symbolic input:
+@examples[#:eval rosette-eval #:label #f
+(eval:no-prompt
+ (define (bvsqrt n)
+  (cond
+    [(bvult n (int32 2)) n]
+    [else
+     (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+     (define s1 (bvadd s0 (int32 1)))
+     (if (bvugt (bvmul s1 s1) n) s0 s1)])))
+(bvsqrt (int32 3))
+(bvsqrt (int32 4))
+(bvsqrt (int32 15))
+(bvsqrt (int32 16))
+(eval:alts
+(with-deep-time-limit 10 (code:comment "Timeout after 10 seconds ...")
+  (bvsqrt l))
+(eval:error (error 'call-with-deep-time-limit "out of time")))]
+The reason is simple: a call to @racket[bvsqrt] terminates when @racket[n] becomes less than 2. But if we start with a symbolic @racket[n], this never happens because Rosette right-shifts @racket[n] by 2 in each recursive call to generate a new symbolic value:
+@examples[#:eval rosette-eval #:label #f
+(define n0 l)
+n0
+(define n1 (bvlshr n0 (int32 2)))      
+n1
+(define n2 (bvlshr n1 (int32 2))) 
+n2
+(define n3 (bvlshr n2 (int32 2))) 
+n3]
+In general, recursion terminates under symbolic evaluation only when the stopping condition is reached with concrete values.
+
+We can force termination by placing a concrete bound @var{k} on the number of times @racket[bvsqrt] can call itself recursively. This approach is called @deftech{finitization}, and it is the standard way to handle unbounded loops and recursion under symbolic evaluation. The following code shows how to implement a @emph{sound} finitization policy. If a @racket[verify] query returns @racket[(unsat)] under a sound policy, we know that (1) the unrolling bound @var{k} is sufficient to execute all possible inputs to  @racket[bvsqrt], and (2) all of these executions satisfy the query. If we pick a bound that is too small, the query will generate a counterexample input that needs a larger bound to compute the result. In our example, the bound of 16 is sufficient to verify the correctness of @racket[bvsqrt] on all inputs:
+@(rosette-eval '(clear-vc!))
+@(rosette-eval '(require (only-in racket make-parameter parameterize)))
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(code:comment "Parameter that controls the number of unrollings (5 by default).")  
+(define fuel (make-parameter 5)) 
+
+(eval:no-prompt)
+(code:comment "A simple macro for defining bounded procedures")
+(code:comment "that use (fuel) to limit recursion.")
+(define-syntax-rule
+  (define-bounded (id param ...) body ...)
+  (define (id param ...)
+    (assert (> (fuel) 0) "Out of fuel.")
+    (parameterize ([fuel (sub1 (fuel))])
+      body ...)))
+
+(eval:no-prompt)
+(code:comment "Computes bvsqrt taking at most (fuel) steps.")
+(define-bounded (bvsqrt n) 
+  (cond
+    [(bvult n (int32 2)) n]
+    [else
+     (define s0 (bvshl (bvsqrt (bvlshr n (int32 2))) (int32 1)))
+     (define s1 (bvadd s0 (int32 1)))
+     (if (bvugt (bvmul s1 s1) n) s0 s1)]))
+
+(eval:no-prompt)
+(code:comment "Correctness specification for bvsqrt:")
+(code:line
+(define (check-sqrt impl n)
+  (assume (bvsle (int32 0) n))          (code:comment "Assuming n ≥ 0,")
+  (define √n (impl l))                 
+  (define √n+1 (bvadd √n (int32 1)))    (code:comment "we require that")
+  (assert (bvule (bvmul √n √n) n))      (code:comment "(√n)^2 ≤ n and")
+  (assert (bvult n (bvmul √n+1 √n+1)))) (code:comment "n < (√n + 1)^2."))]
+
+@examples[#:eval rosette-eval #:label #f
+(code:comment "Verification fails due to insufficient fuel.")
+(define cex (time (verify (check-sqrt bvsqrt l))))
+(eval:error (bvsqrt (evaluate l cex)))
+(clear-vc!)
+(code:comment "Verification succeeds with enough fuel.")
+(fuel 16)
+(time (verify (check-sqrt bvsqrt l)))]
+
+Many other finitization policies can be defined in a similar way. For example, if we change @racket[define-bounded] to use @racket[assume] instead of @racket[assert], we obtain a finitization policy that ensures @emph{completeness}. If a @racket[verify] query returns a counterexample under a complete policy, we know that the program is buggy, and it violates a query assertion within @var{k} recursive calls. But if the query returns @racket[(unsat)], we know only that there are no bugs within @var[k] or fewer unrollings---we cannot conclude anything about longer executions. So a complete policy prevents false positives, while a sound one prevents false negatives. What kind of policy to use depends on the application, and Rosette leaves that choice to the programmer.
 
-See Chapters @seclink["ch:symbolic-reflection"]{7} and @seclink["ch:unsafe"]{8} to
-learn more about common patterns and anti-patterns for effective symbolic reasoning.
 
 @(kill-evaluator rosette-eval)
 

rosette/guide/scribble/essentials/poly.rkt

@@ -1,41 +0,0 @@
-#lang rosette/safe
-
-(require rosette/query/debug rosette/lib/render) 
- 
-(define (poly x)
- (+ (* x x x x) (* 6 x x x) (* 11 x x) (* 6 x)))
- 
-(define/debug (factored x)
- (* x (+ x 1) (+ x 2) (+ x 2)))
- 
-(define (same p f x)
- (assert (= (p x) (f x))))
-
-(define-symbolic i integer?)
-
-(define cex (verify (same poly factored i)))
-
-(evaluate i cex)
-
-(define c (debug [integer?] (same poly factored -6)))
-(render c)
-
-(require rosette/lib/synthax)
-
-(define (factored* x)        
-  (* (+ x (??)) (+ x 1) (+ x (??)) (+ x (??))))  
-
-(define binding 
-  (synthesize #:forall (list i)
-              #:guarantee (same poly factored* i)))
-
-(print-forms binding)
-
-(define-symbolic x y integer?)
-(define env 
-  (solve (begin (assert (not (= x y)))
-                (assert (< (abs x) 10))
-                (assert (< (abs y) 10))
-                (assert (not (= (poly x) 0)))
-                (assert (= (poly x) (poly y))))))
-env

rosette/guide/scribble/forms/forms.scrbl

@@ -5,7 +5,7 @@
 
 @title[#:tag "ch:syntactic-forms" #:style 'toc]{Syntactic Forms}
 
-The core of the Rosette language (@racket[rosette/safe]) consists of two kinds of syntax forms: a set of basic  forms @deftech[#:key "lifted constructs"]{lifted} from Racket, and a set of forms for @seclink["ch:essentials"]{solver-aided programming}.  We use the term "lifted" to refer to parts of the Racket language that can be used with symbolic values and other solver-aided constructs.
+The core of the Rosette language (@racketmodname[rosette/safe]) consists of two kinds of syntax forms: a set of basic  forms @deftech[#:key "lifted constructs"]{lifted} from Racket, and a set of forms for @seclink["ch:essentials"]{solver-aided programming}.  We use the term ``lifted'' to refer to parts of the Racket language that can be used with symbolic values and other solver-aided constructs.
 
 @[table-of-contents]
 @include-section["racket-forms.scrbl"]

rosette/guide/scribble/forms/racket-forms.scrbl

@@ -2,7 +2,7 @@
 
 @(require (for-label rosette/base/form/define)
           (for-label racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+          scribble/core scribble/html-properties scribble/examples racket/sandbox
           "../util/lifted.rkt")
 
 
@@ -58,7 +58,7 @@ Rosette lifts the following @seclink["syntax" #:doc '(lib "scribblings/reference
       (list @elem{Syntax Quoting} @syntax-quoting))]
 
 Lifted forms have the same meaning in Rosette programs as they do in Racket programs. For example, the Racket expression @racket[(if #, @var[test-expr] #, @var[then-expr] #, @var[else-expr])] evaluates @var[test-expr] first and then, depending on the outcome, it returns the result of evaluating either @var[then-expr] or @var[else-expr]. Rosette preserves this interpretation of @racket[if] for concrete values, and also extends it to work with symbolic values:
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
  (let ([y 0])
    (if #t (void) (set! y 3))
    (printf "y unchanged: ~a\n" y)

rosette/guide/scribble/forms/rosette-forms-log.txt

@@ -12,7 +12,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "x"))))
+  (c values c (0 (u . "x\n"))))
  #""
  #"")
 ((always-same)
@@ -24,10 +24,54 @@
   0
   ()
   ()
-  (c values c (0 (u . "x"))))
+  (c values c (0 (u . "x\n"))))
+ #""
+ #"")
+((equal? (always-same) (always-same)) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((define (always-same-3) (define-symbolic y integer? #:length (+ 1 2)) y)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((always-same-3)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list y$0 y$1 y$2)\n"))))
+ #""
+ #"")
+((always-same-3)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list y$0 y$1 y$2)\n"))))
+ #""
+ #"")
+((equal? (always-same-3) (always-same-3))
+ ((3) 0 () 0 () () (q values #t))
+ #""
+ #"")
+((lambda (n) (define-symbolic y integer? #:length n) y)
+ ((3)
+  0
+  ()
+  0
+  ()
+  ()
+  (q
+   exn
+   "eval:9.0: define-symbolic: expected a natural? for #:length\n  at: (define-symbolic y integer? #:length n)\n  in: (define-symbolic y integer? #:length n)"))
  #""
  #"")
-((eq? (always-same) (always-same)) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((define (always-different) (define-symbolic* x integer?) x)
  ((3) 0 () 0 () () (c values c (void)))
  #""
@@ -41,7 +85,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "x$0"))))
+  (c values c (0 (u . "x$0\n"))))
  #""
  #"")
 ((always-different)
@@ -53,7 +97,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "x$1"))))
+  (c values c (0 (u . "x$1\n"))))
  #""
  #"")
 ((eq? (always-different) (always-different))
@@ -65,15 +109,55 @@
   0
   ()
   ()
-  (c values c (0 (u . "(= x$2 x$3)"))))
+  (c values c (0 (u . "(= x$2 x$3)\n"))))
+ #""
+ #"")
+((define (always-different-n n) (define-symbolic* y integer? #:length n) y)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((always-different-n 2)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list y$4 y$5)\n"))))
+ #""
+ #"")
+((always-different-n 3)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list y$6 y$7 y$8)\n"))))
+ #""
+ #"")
+((equal? (always-different-n 4) (always-different-n 4))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0 (u . "(&& (= y$9 y$13) (= y$10 y$14) (= y$11 y$15) (= y$12 y$16))\n"))))
  #""
  #"")
 ((assert #t) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((assert 1) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts) ((3) 0 () 0 () () (q values ())) #"" #"")
-((define-symbolic x boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -82,14 +166,28 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "x")))))
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic x boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assert x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t x)\n"))))
  #""
  #"")
 ((assert #f "bad value")
- ((3) 0 () 0 () () (q exn "assert: bad value"))
+ ((3) 0 () 0 () () (q exn "[assert] bad value"))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -98,14 +196,11 @@
   0
   ()
   ()
-  (c values c (c #f c (0 (u . "x")))))
+  (c values c (0 (u . "(vc #t #f)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts) ((3) 0 () 0 () () (q values ())) #"" #"")
-((define-symbolic x y boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -114,14 +209,83 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "x")))))
+  (c values c (0 (u . "(vc #t #t)\n"))))
  #""
  #"")
-((define sol (solve (assert y)))
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((assume #t) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume 1) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic x boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc x #t)\n"))))
+ #""
+ #"")
+((assume #f "bad value")
+ ((3) 0 () 0 () () (q exn "[assume] bad value"))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #f #t)\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic a b c d boolean?)
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((asserts)
+((vc)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -130,11 +294,271 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "x")))))
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((verify (assert a))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [a #f])\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((assume a) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assert b) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a (|| b (! a)))\n"))))
+ #""
+ #"")
+((verify (begin (assume c) (assert d)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [a #t]\n [b #t]\n [c #t]\n [d #f])\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a (|| b (! a)))\n"))))
+ #""
+ #"")
+((verify (assert a))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((verify (assert a))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [a #f])\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic x c integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((synthesize
+  #:forall
+  (list x)
+  #:guarantee
+  (begin (assume (even? x)) (assert (odd? (+ x c)))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [c 1])\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((assume (odd? x)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc (! (= 0 (remainder x 2))) #t)\n"))))
+ #""
+ #"")
+((synthesize #:forall (list x) #:guarantee (assert (odd? (+ x c))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [c 0])\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc (! (= 0 (remainder x 2))) #t)\n"))))
+ #""
+ #"")
+((synthesize
+  #:forall
+  (list x)
+  #:guarantee
+  (begin (assume (even? x)) (assert (odd? (+ x c)))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((synthesize
+  #:forall
+  (list x)
+  #:guarantee
+  (begin (assume (even? x)) (assert (odd? (+ x c)))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [c 1])\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic x y boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc x #t)\n"))))
+ #""
+ #"")
+((solve (assert y))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [x #t]\n [y #t])\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc x #t)\n"))))
  #""
  #"")
-((evaluate x sol) ((3) 0 () 0 () () (q values #t)) #"" #"")
-((evaluate y sol) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((solve (assert (not x)))
  ((3)
   1
@@ -144,10 +568,35 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((solve (assert (not x)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [x #f])\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define inc (solve+)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((inc (< x y))
@@ -159,7 +608,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0]\n [y 1])"))))
+  (c values c (0 (u . "(model\n [x 0]\n [y 1])\n"))))
  #""
  #"")
 ((inc (> x 5))
@@ -171,7 +620,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 6]\n [y 7])"))))
+  (c values c (0 (u . "(model\n [x 6]\n [y 7])\n"))))
  #""
  #"")
 ((inc (< y 4))
@@ -183,7 +632,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
 ((inc 1)
@@ -195,7 +644,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 6]\n [y 7])"))))
+  (c values c (0 (u . "(model\n [x 6]\n [y 7])\n"))))
  #""
  #"")
 ((inc (< y 9))
@@ -207,7 +656,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 6]\n [y 7])"))))
+  (c values c (0 (u . "(model\n [x 6]\n [y 7])\n"))))
  #""
  #"")
 ((inc 'shutdown) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -220,103 +669,16 @@
   ()
   (q
    exn
-   "solver-push: contract violation:\nexpected: solver?\ngiven: #f\nargument position: 1st"))
+   "solver-push: contract violation:\n  expected: solver?\n  given: #f\n  argument position: 1st"))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-symbolic x y boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert x) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (c (0 (u . "x")))))
- #""
- #"")
-((define sol (verify (assert y)))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((asserts)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (c (0 (u . "x")))))
- #""
- #"")
-((evaluate x sol) ((3) 0 () 0 () () (q values #t)) #"" #"")
-((evaluate y sol) ((3) 0 () 0 () () (q values #f)) #"" #"")
-((verify #:assume (assert y) #:guarantee (assert (and x y)))
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (0 (u . "(unsat)"))))
- #""
- #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-symbolic x c integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert (even? x)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (c (0 (u . "(= 0 (remainder x 2))")))))
- #""
- #"")
-((define sol (synthesize #:forall x #:guarantee (assert (odd? (+ x c)))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((asserts)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (c (0 (u . "(= 0 (remainder x 2))")))))
- #""
- #"")
-((evaluate x sol)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (0 (u . "x"))))
- #""
- #"")
-((evaluate c sol) ((3) 0 () 0 () () (q values 77)) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((current-bitwidth #f) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((assert (< x 2)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((asserts)
+((optimize
+  #:maximize
+  (list (+ x y))
+  #:guarantee
+  (begin (assume (< x 2)) (assert (< (- y x) 1))))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -325,29 +687,10 @@
   0
   ()
   ()
-  (c values c (c (0 (u . "(< x 2)")))))
+  (c values c (0 (u . "(model\n [x 1]\n [y 1])\n"))))
  #""
  #"")
-((define sol
-   (optimize #:maximize (list (+ x y)) #:guarantee (assert (< (- y x) 1))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((asserts)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (c (0 (u . "(< x 2)")))))
- #""
- #"")
-((evaluate x sol) ((3) 0 () 0 () () (q values 1)) #"" #"")
-((evaluate y sol) ((3) 0 () 0 () () (q values 1)) #"" #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((current-bitwidth 5) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic x y real?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic f (~> real? real?))
@@ -364,7 +707,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 3])"))))
+  (c values c (0 (u . "(model\n [x 3])\n"))))
  #""
  #"")
 ((solve (assert (= x 64)))
@@ -376,7 +719,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0])"))))
+  (c values c (0 (u . "(model\n [x 0])\n"))))
  #""
  #"")
 ((solve (assert (and (= x 64) (= x 0))))
@@ -388,7 +731,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0])"))))
+  (c values c (0 (u . "(model\n [x 0])\n"))))
  #""
  #"")
 ((solve (assert (forall (list x) (= x (+ x y)))))
@@ -425,7 +768,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 7/2])"))))
+  (c values c (0 (u . "(model\n [x 7/2])\n"))))
  #""
  #"")
 ((solve (assert (= x 64)))
@@ -437,7 +780,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 64])"))))
+  (c values c (0 (u . "(model\n [x 64])\n"))))
  #""
  #"")
 ((solve (assert (and (= x 64) (= x 0))))
@@ -449,7 +792,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
 ((solve (assert (forall (list x) (= x (+ x y)))))
@@ -461,7 +804,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [y 0])"))))
+  (c values c (0 (u . "(model\n [y 0])\n"))))
  #""
  #"")
 ((solve (assert (= x (f x))))
@@ -473,7 +816,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(model\n [x 0]\n [f (fv real?~>real?)])"))))
+  (c values c (0 (u . "(model\n [x 0]\n [f (fv real?~>real?)])\n"))))
  #""
  #"")
 ((define-symbolic i j integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
@@ -490,6 +833,6 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unknown)"))))
+  (c values c (0 (u . "(unknown)\n"))))
  #""
  #"")

rosette/guide/scribble/forms/rosette-forms.scrbl

@@ -1,17 +1,17 @@
 #lang scribble/manual
 
 @(require (for-label  
-           rosette/base/form/define rosette/query/form rosette/query/eval rosette/solver/solution
+           rosette/base/form/define rosette/query/query rosette/solver/solution
            (only-in rosette/solver/solver solver?)
-           rosette/base/core/term (only-in rosette/query/debug define/debug debug)
+           rosette/base/core/term 
            (only-in rosette/query/finitize current-bitwidth)
-           (only-in rosette/base/core/safe assert) 
-           (only-in rosette/base/core/bool asserts clear-asserts!)
-           (only-in rosette/base/base bv?)
-           (only-in rosette/base/core/function function?)
+           (only-in rosette/base/base
+                    assert assume vc vc-asserts vc-assumes clear-vc!
+                    bv? forall)
+           (only-in rosette/base/core/function function? ~>)
            (only-in rosette/base/core/reflect symbolics))
           (for-label racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox  racket/runtime-path 
+          scribble/core scribble/html-properties scribble/examples racket/sandbox  racket/runtime-path 
           "../util/lifted.rkt")
 
 @(define-runtime-path root ".")
@@ -19,42 +19,75 @@
 
 @title[#:tag "ch:syntactic-forms:rosette"]{Solver-Aided Forms}
 
-The @seclink["ch:essentials"]{Essentials} chapter introduced the key concepts of solver-aided programming.  This section defines the corresponding syntactic constructs more precisely.
+The @seclink["ch:essentials"]{Essentials} chapter introduced
+the key concepts of solver-aided programming. This section
+describes the corresponding syntactic constructs in detail.
 
 @declare-exporting[rosette/base/form/define 
                    rosette/query/form 
-                   rosette/base/core/safe
+                   rosette/base/base
                    rosette/base/core/bool
                    rosette/query/finitize
                    #:use-sources 
                    (rosette/base/form/define 
                    rosette/query/form
-                   rosette/base/core/safe
+                   rosette/base/base
                    rosette/base/core/bool
                    rosette/query/finitize)]
 
 @section[#:tag "sec:symbolic-constants"]{Symbolic Constants}
 
-@defform[(define-symbolic id ...+ type)
+@defform*[((define-symbolic id ...+ type)
+           (define-symbolic id type #:length k))
          #:contracts
-         [(type (and/c solvable? type?))]]{
-  Binds each provided identifier to a distinct @tech["symbolic constant"] of the given 
-  @tech["solvable type"].  The identifiers are bound to the same constants every time the form is 
-  evaluated.  
+         [(type (and/c solvable? type?))
+          (k natural?)]]{
+                         
+ The first form binds each provided identifier to a distinct
+ @tech["symbolic constant"] of the given
+ @tech["solvable type"]. The identifiers are bound to the
+ same constants every time the form is evaluated.
+  
   @examples[#:eval rosette-eval
   (define (always-same)
     (define-symbolic x integer?)
     x)
   (always-same)
   (always-same) 
-  (eq? (always-same) (always-same))]
+  (equal? (always-same) (always-same)) ]
+
+ The second form creates a list of @racket[k] distinct
+ constants and binds it to @racket[id]. The same constants
+ are bound to @racket[id] every time the form is evaluated.
+ The form requires @racket[k] to evaluate to a natural number
+ statically---i.e., at macro expansion time.
+
+  @examples[#:eval rosette-eval
+  (define (always-same-3)
+    (define-symbolic y integer? #:length (+ 1 2))
+    y)
+  (always-same-3)
+  (always-same-3) 
+  (equal? (always-same-3) (always-same-3))
+  (eval:alts
+   (define (always-same-n n)
+     (define-symbolic y integer? #:length n)
+    y)
+   (eval:error (lambda (n) (define-symbolic y integer? #:length n) y)))]
 }
-@defform[(define-symbolic* id ...+ type)
+
+@defform*[((define-symbolic* id ...+ type)
+           (define-symbolic* id type #:length k))
          #:contracts
-         [(type (and/c solvable? type?))]]{
-  Creates a stream of distinct @tech["symbolic constant"]s of the given 
-  @tech["solvable type"] for each identifier, binding the identifier to the 
-  next element from its stream every time the form is evaluated.  
+         [(type (and/c solvable? type?))
+          (k natural?)]]{
+                         
+ The first form creates a stream of distinct
+ @tech["symbolic constant"]s of the given
+ @tech["solvable type"] for each identifier, binding the
+ identifier to the next element from its stream every time
+ the form is evaluated.
+  
   @examples[#:eval rosette-eval
   (define (always-different)
     (define-symbolic* x integer?)
@@ -62,65 +95,266 @@ The @seclink["ch:essentials"]{Essentials} chapter introduced the key concepts of
   (always-different) 
   (always-different) 
   (eq? (always-different) (always-different))]
-}
 
-@section[#:tag "sec:assertions"]{Assertions}
+ The second form binds @racket[id] to a list of the next
+ @racket[k] elements from its stream every time the form is
+ evaluated. The expression @racket[k] may produce different
+ natural numbers depending on the calling context.
 
-@defform[(assert expr maybe-message)
-         #:grammar
-         [(maybe-message (code:line) msg)]
-         #:contracts
-         [(msg (or/c string? procedure?))]]{
-  Provides a mechanism for communicating desired
-  program properties to the underlying solver.  Rosette keeps track of all
-  assertions evaluated during an execution in an @tech{assertion store}. 
-  If @racket[expr] evaluates to @racket[#f], an error is thrown using the 
-  optional failure message, and @racket[#f] is added to the assertion store.  The error message
-  can be either a string or a no-argument procedure that throws an error when called.
-  If @racket[expr] evaluates to a symbolic boolean value, that value is added to the assertion store.
-  If @racket[expr] evaluates to any other value, @racket[assert] has no effect.  The contents
-  of the assertion store can be examined using the @racket[asserts] procedure, and they can be
-  cleared using the @racket[clear-asserts!] procedure. 
   @examples[#:eval rosette-eval
-  (code:line (assert #t) (code:comment "no effect"))
-  (code:line (assert 1)  (code:comment "no effect"))
-  (code:line (asserts)   (code:comment "retrieve the assertion store"))  
+  (define (always-different-n n)
+    (define-symbolic* y integer? #:length n)
+    y)
+  (always-different-n 2)
+  (always-different-n 3) 
+  (equal? (always-different-n 4) (always-different-n 4))]}
+
+@section[#:tag "sec:assertions"]{Assertions and Assumptions}
+
+@defform*[((assert expr)
+           (assert expr msg))
+         #:contracts
+         [(msg string?)]]{
+                          
+ Checks that @racket[expr] produces a true value. Rosette
+ keeps track of all assertions and assumptions encountered
+ during symbolic evaluation in the current @tech{verification condition} (VC).
+ If @racket[expr] evaluates to @racket[#f],
+ the assertion adds @racket[#f] to the VC and throws an error
+ with the optional failure message @racket[msg]. If
+ @racket[expr] evaluates to a symbolic boolean value, this
+ value is added to the VC and execution continues. If
+ @racket[expr] evaluates to any other value, @racket[assert]
+ has no effect. The contents of the VC can be examined using
+ the @racket[(vc)] procedure, and they can be cleared using
+ the @racket[clear-vc!] procedure.
+
+  @examples[#:eval rosette-eval
+  (code:line (assert #t) (code:comment "No effect."))
+  (code:line (assert 1)  (code:comment "No effect."))
+  (code:line (vc)        (code:comment "The VC tracks assumptions and assertions."))  
   (define-symbolic x boolean?)
   (assert x)
-  (code:line (asserts)   (code:comment "x added to the assertion store"))  
-  (assert #f "bad value")
-  (asserts) 
-  (code:line (clear-asserts!)   (code:comment "clear the assertion store"))
-  (asserts)]
+  (code:line (vc)        (code:comment "x is added to the VC's asserts."))  
+  (eval:error (assert #f "bad value"))
+  (vc) 
+  (code:line (clear-vc!) (code:comment "Clear the VC."))
+  (vc)]
 }
 
+@defform*[((assume expr)
+           (assume expr msg))
+         #:contracts
+         [(msg string?)]]{
+                          
+ Behaves like @racket[assert] except that it updates the
+ assumption component of the current verification condition
+ when @racket[expr] evaluates to @racket[#f] or to a
+ symbolic boolean.
+
+ @examples[#:eval rosette-eval
+  (vc)
+  (code:line (assume #t) (code:comment "No effect."))
+  (code:line (assume 1)  (code:comment "No effect."))
+  (code:line (vc)        (code:comment "The VC tracks assumptions and assertions."))  
+  (define-symbolic x boolean?)
+  (assume x)
+  (code:line (vc)        (code:comment "x is added to the VC's assumes."))  
+  (eval:error (assume #f "bad value"))
+  (vc) 
+  (code:line (clear-vc!) (code:comment "Clear the VC."))
+  (vc)]
+}
+
+
+
+@section{Verification}
+
+@defform[(verify expr)]{
+
+ Searches for a binding of symbolic constants to concrete
+ values that satisfies all the assumptions and violates at
+ least one of the assertions encountered during the
+ evaluation of @racket[expr]. The binding must also satisfy
+ all the assumptions and assertions accumulated in the
+ verification condition @racket[(vc)] before the call to
+ @racket[verify]. If such a binding exists, the query returns
+ one as part of a satisfiable @racket[solution?]; otherwise,
+ the query returns @racket[(unsat)].
+
+ Formally,
+ @racket[(verify expr)] searches for a model of the formula
+ @racket[(vc-assumes #, @var{P})] ∧ @racket[(vc-asserts #, @var{P})] ∧
+ @racket[(vc-assumes #, @var{Q})] ∧ ¬ @racket[(vc-asserts #, @var{Q})],
+ where @var{P} is the verification condition before the
+ call to @racket[verify] and @var{Q} is the verification condition
+ generated by evaluating @racket[expr].
+
+ The @racket[verify]
+ query does not retain the assumptions and assertions generated
+ by @racket[expr], leaving the current verification condition
+ @racket[(vc)] unchanged after the query returns.
+
+  @examples[#:eval rosette-eval
+  (define-symbolic a b c d boolean?)
+  (vc)
+  (code:comment "This query forces a to be false:")
+  (verify (assert a)) 
+  (code:line (vc) (code:comment "VC is unchanged."))
+  (assume a)           
+  (assert b)           
+  (vc)
+  (code:comment "This query forces a, b, c to be true, and d to be false:")
+  (verify 
+   (begin
+     (assume c)  
+     (assert d)))
+  (vc)
+  (code:comment "This query has no solution because we assumed a above:")
+  (verify (assert a))
+  (code:comment "Clearing the VC gives the expected solution:")
+  (clear-vc!)
+  (vc)
+  (verify (assert a))] 
+}
+
+@(rosette-eval '(clear-vc!))
+
+@section{Synthesis}
+
+
+@defform*[((synthesize input expr)
+           (synthesize #:forall input #:guarantee expr))]{
+
+ Taking @var{I} to be the set of symbolic constants @racket[(symbolics input)] 
+ and @var{H} to be the complement of @var{I}, 
+ searches for a binding @var{B}@subscript{@var{H}}
+ from @var{H} to concrete values that 
+ satisfies @racket[expr] as follows.
+ If @var{B}@subscript{@var{H}} is extended with any binding
+ @var{B}@subscript{@var{I}} from @var{I}
+ to concrete values, then the extended binding
+ @var{B}@subscript{@var{H}} ∪ @var{B}@subscript{@var{I}}
+ satisfies all the assertions generated by evaluating @racket[expr] whenever
+ it satisfies the assumptions generated by @racket[expr], as
+ well as the assumptions and assertions accumulated in the verification condition
+ @racket[(vc)] before @racket[expr] is evaluated. If such a binding
+ @var{B}@subscript{@var{H}} exists, the query returns one as part of a
+ satisfiable @racket[solution?]; otherwise, the query returns
+ @racket[(unsat)].
+
+ Formally, @racket[(synthesize input expr)] searches for a model of 
+ the formula
+ ∃ @var{H}. (∃ @var{I}. @var{pre}(@var{H}, @var{I})) ∧
+ (∀ @var{I}. @var{pre}(@var{H}, @var{I}) ⇒ @var{post}(@var{H}, @var{I})),
+ where @var{pre}(@var{H}, @var{I}) is @racket[(vc-assumes #, @var{P})] ∧
+ @racket[(vc-asserts #, @var{P})] ∧ @racket[(vc-assumes #, @var{Q})],
+ @var{post}(@var{H}, @var{I}) is @racket[(vc-asserts #, @var{Q})],
+ @var{P} is the verification condition accumulated before the evaluation of 
+ @racket[expr], and @var{Q} is the verification condition
+ generated by evaluating @racket[expr]. This formula is stronger than the
+ classic synthesis formula
+ ∃ @var{H}. ∀ @var{I}. @var{pre}(@var{H}, @var{I}) ⇒ @var{post}(@var{H}, @var{I}).
+ The additional constraint, ∃ @var{I}. @var{pre}(@var{H}, @var{I}), rules out
+ trivial solutions that allow @var{pre}(@var{H}, @var{I}) to 
+ be false on all inputs @var{I}. 
+ The formulas @var{pre}(@var{H}, @var{I}) and
+ @var{post}(@var{H}, @var{I}) are required to be free of quantifiers, so
+ no @tech[#:key "quantified formula"]{quantified formulas} can be part of 
+ the assumptions or assertions that make up a synthesis query.
+ 
+ The @racket[synthesize] query does not retain the
+ assumptions and assertions generated by @racket[expr],
+ but it does retain the updates to @racket[(vc)], if any,
+ produced by evaluating @racket[input]. In other words,
+ @racket[(synthesize input expr)] is equivalent to
+ @racket[(let ([v input]) (synthesize v expr))], where @racket[v]
+ is a fresh variable. 
+  
+  @examples[#:eval rosette-eval
+  (define-symbolic x c integer?)
+  (vc)
+  (code:comment "This query finds a binding for c that works for all even x:")
+  (synthesize
+     #:forall (list x) 
+     #:guarantee
+     (begin
+       (assume (even? x))
+       (assert (odd? (+ x c)))))
+  (code:line (vc)   (code:comment "VC is unchanged."))
+  (assume (odd? x))
+  (vc)
+  (code:comment "This query finds a binding for c that works for all odd x:")
+  (synthesize
+   #:forall    (list x)
+   #:guarantee (assert (odd? (+ x c))))
+  (vc)
+  (code:comment "This query has no solution because we assumed (odd? x) above:")
+  (synthesize
+   #:forall (list x)
+   #:guarantee
+   (begin
+     (assume (even? x))
+     (assert (odd? (+ x c)))))
+  (code:comment "Clearing the VC gives the expected solution:")
+  (clear-vc!)
+  (vc)
+  (synthesize
+   #:forall (list x)
+   #:guarantee
+   (begin
+     (assume (even? x))
+     (assert (odd? (+ x c)))))]
+}
+
+@(rosette-eval '(clear-vc!))
+
 @section{Angelic Execution}
 
 @defform[(solve expr)]{
-  Searches for a binding of symbolic constants to concrete values that satisfies all assertions encountered
-  before the invocation of @racket[solve] and during the evaluation of @racket[expr]. 
-  If such a binding exists, it is returned in the form of a satisfiable @racket[solution?]; otherwise, 
-  the result is an unsatisfiable solution.  The assertions encountered while 
-  evaluating @racket[expr] are removed from the global @tech["assertion store"] once @racket[solve] returns.  As a result, 
-  @racket[solve] has no observable effect on the @tech["assertion store"]. 
-  The solver's ability to find solutions depends on the current @tech["reasoning precision"], as
-  determined by the @racket[current-bitwidth] parameter.
+                       
+ Searches for a binding of symbolic constants to concrete
+ values that satisfies all the assumptions and assertions
+ encountered during the evaluation of @racket[expr], as well
+ as all the assumptions and assertions accumulated in the
+ verification condition @racket[(vc)] before the call to
+ @racket[solve]. If such a binding exists, the query returns
+ one as part of a satisfiable @racket[solution?]; otherwise,
+ the result is an unsatisfiable solution.
+ 
+ Formally,
+ @racket[(solve expr)] searches for a model of the formula
+ @racket[(vc-assumes #, @var{P})] ∧ @racket[(vc-asserts #, @var{P})] ∧
+ @racket[(vc-assumes #, @var{Q})] ∧ @racket[(vc-asserts #, @var{Q})],
+ where @var{P} is the verification condition before the
+ call to @racket[solve] and @var{Q} is the verification condition
+ generated by evaluating @racket[expr].
+
+ The @racket[solve]
+ query does not retain the assumptions and assertions generated
+ by @racket[expr], leaving the current verification condition
+ @racket[(vc)] unchanged after the query returns.
+ 
  @examples[#:eval rosette-eval
  (define-symbolic x y boolean?)
-  (assert x)
-  (code:line (asserts)   (code:comment "x added to the assertion store"))  
-  (define sol (solve (assert y)))
-  (code:line (asserts)   (code:comment "assertion store same as before")) 
-  (code:line (evaluate x sol) (code:comment "x must be true"))
-  (code:line (evaluate y sol) (code:comment "y must be true"))
+ (assume x)
+ (code:line (vc)   (code:comment "x is added to the VC's assumes."))
+ (code:comment "This query forces both x and y to be true.")
+ (solve (assert y))
+ (code:line (vc)   (code:comment "VC is unchanged."))
+ (code:comment "This query has solution because we assumed (not x) above:")
+ (solve (assert (not x)))
+ (code:comment "Clearing the VC gives the expected solution:")
+ (clear-vc!)
+ (vc)
  (solve (assert (not x)))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @defproc[(solve+) procedure?]{
 Returns a stateful procedure that uses a fresh @racket[solver?] instance
-to incrementally solve a sequence of constraints (with respect to @racket[current-bitwidth]).
+to incrementally solve a sequence of constraints.
 
 The returned procedure consumes a constraint (i.e., a boolean value or @tech["symbolic term"]),
 a positive integer, or the symbol @racket['shutdown].
@@ -136,153 +370,78 @@ subsequent calls to the procedure throw an exception.
  @examples[#:eval rosette-eval
   (define-symbolic x y integer?)
   (define inc (solve+))
-  (code:line (inc (< x y))   (code:comment "push (< x y) and solve"))
-  (code:line (inc (> x 5))   (code:comment "push (> x 5) and solve"))
-  (code:line (inc (< y 4))   (code:comment "push (< y 4) and solve"))
-  (code:line (inc 1)         (code:comment "pop  (< y 4) and solve"))
-  (code:line (inc (< y 9))   (code:comment "push (< y 9) and solve"))
-  (code:line (inc 'shutdown) (code:comment "release resources"))
-  (code:line (inc (> y 4))   (code:comment "unusable"))
- ]
+  (code:line (inc (< x y))   (code:comment "Push (< x y) and solve."))
+  (code:line (inc (> x 5))   (code:comment "Push (> x 5) and solve."))
+  (code:line (inc (< y 4))   (code:comment "Push (< y 4) and solve."))
+  (code:line (inc 1)         (code:comment "Pop  (< y 4) and solve."))
+  (code:line (inc (< y 9))   (code:comment "Push (< y 9) and solve."))
+  (code:line (inc 'shutdown) (code:comment "Release resources."))
+  (eval:alts
+   (code:line (inc (> y 4))   (code:comment "Unusable after shutdown."))
+   (eval:error (inc (> y 4))))]
 }
 
 
-@(rosette-eval '(clear-asserts!))
-
-@section{Verification}
-
-@defform*[((verify guarantee-expr)
-           (verify #:assume assume-expr #:guarantee guarantee-expr))]{
-  Searches for a binding of symbolic constants to concrete values that violates at least one of the 
-  assertions encountered during the evaluation of @racket[guarantee-expr], but that satisfies all 
-  assertions encountered before the invocation of @racket[verify] and during the evaluation of 
-  @racket[assume-expr]. If such a binding exists, it is returned in the form of a
-  satisfiable @racket[solution?]; otherwise, the result is an unsatisfiable solution.  The assertions encountered while 
-  evaluating @racket[assume-expr] and @racket[guarantee-expr] are removed from the global @tech["assertion store"] once 
-  @racket[verify] returns.   
-  The solver's ability to find solutions depends on the current @tech["reasoning precision"], as
-  determined by the @racket[current-bitwidth] parameter.
-  @examples[#:eval rosette-eval
-  (define-symbolic x y boolean?)
-  (assert x)
-  (code:line (asserts)   (code:comment "x added to the assertion store")) 
-  (define sol (verify (assert y)))
-  (code:line (asserts)   (code:comment "assertion store same as before")) 
-  (code:line (evaluate x sol) (code:comment "x must be true"))
-  (code:line (evaluate y sol) (code:comment "y must be false"))
-  (verify #:assume (assert y) #:guarantee (assert (and x y)))]
-}
-
-@(rosette-eval '(clear-asserts!))
-
-@section{Synthesis}
-
-@defform*[((synthesize input-expr expr)
-           (synthesize
-            #:forall input-expr
-            maybe-assume
-            #:guarantee guarantee-expr))
-          #:grammar ([maybe-assume (code:line) (code:line #:assume assume-expr)])]{
-  Searches for a binding of symbolic constants 
-  to concrete values that has the following properties: 
-  @itemlist[#:style 'ordered
-  @item{it does not map the constants in @racket[(symbolics input-expr)]; and,} 
-  @item{it satisfies all assertions encountered during the evaluation of 
-  @racket[guarantee-expr], for every binding of @racket[input-expr] constants to values that satisfies 
-  the assertions encountered before the invocation of @racket[synthesize] and during the evaluation of 
-  @racket[assume-expr].}] 
-  If no such binding exists, the result is an unsatisfiable @racket[solution?].  The assertions encountered while 
-  evaluating @racket[assume-expr] and @racket[guarantee-expr] are removed from the global @tech["assertion store"] once 
-  @racket[synthesize] returns.  These assertions @bold{may not include} @tech[#:key "quantified formula"]{quantified formulas}.
-  The solver's ability to find solutions depends on the current @tech["reasoning precision"],
-  as determined by the @racket[current-bitwidth] parameter. 
-  @examples[#:eval rosette-eval
-  (define-symbolic x c integer?)
-  (assert (even? x))
-  (code:line (asserts)   (code:comment "assertion pushed on the store")) 
-  (define sol 
-    (synthesize #:forall x 
-                #:guarantee (assert (odd? (+ x c)))))
-  (code:line (asserts)   (code:comment "assertion store same as before")) 
-  (code:line (evaluate x sol) (code:comment "x is unbound")) 
-  (code:line (evaluate c sol) (code:comment "c must an odd integer"))]
-}
-
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 
 @section{Optimization}
 
 @defform[(optimize
             maybe-minimize
             maybe-maximize
-            #:guarantee guarantee-expr)
-          #:grammar ([maybe-minimize (code:line) (code:line #:minimize minimize-expr)]
-                     [maybe-maximize (code:line) (code:line #:maximize maximize-expr)])
-          #:contracts [(minimize-expr (listof (or/c integer? real? bv?)))
-                       (maximize-expr (listof (or/c integer? real? bv?)))]]{
-  Searches for a binding of symbolic constants to concrete values that satisfies all assertions encountered
-  before the invocation of @racket[optimize] and during the evaluation of @racket[minimize-expr],
-  @racket[maximize-expr], and @racket[guarantee-expr].  
-  If such a binding exists, it is returned in the form of a satisfiable @racket[solution?]; otherwise, 
-  the result is an unsatisfiable solution.  Any satisfiable solution returned by @racket[optimize] is optimal with respect
-  to the cost terms provided in the @racket[minimize-expr] and @racket[maximize-expr] lists.  Specifically, these
-  terms take on the minimum or maximum values when evaluated with respect to a satisfiable solution.  For more details on
+            #:guarantee expr)
+          #:grammar ([maybe-minimize (code:line) (code:line #:minimize min-expr)]
+                     [maybe-maximize (code:line) (code:line #:maximize max-expr)])
+          #:contracts [(min-expr (listof (or/c integer? real? bv?)))
+                       (max-expr (listof (or/c integer? real? bv?)))]]{
+
+ Searches for an optimal binding of symbolic constants to
+ concrete values that satisfies all the assumptions and
+ assertions encountered during the evaluation of
+ @racket[expr], as well as all the assumptions and assertions
+ accumulated in the verification condition @racket[(vc)]
+ before the evaluation of @racket[expr]. The binding is
+ optimal in that it minimizes the cost terms in
+ the @racket[min-expr] list and maximizes those in the
+ @racket[max-expr] list.  If such a binding exists, the query
+ returns one as part of a satisfiable @racket[solution?]; otherwise,
+ the query returns @racket[(unsat)]. For more details on
  solving optimization problems, see the
  @hyperlink["https://rise4fun.com/Z3/tutorial/optimization"]{Z3 optimization tutorial}.
 
-  As is the case for other solver-aided queries, the assertions encountered while 
-  evaluating @racket[minimize-expr],
-  @racket[maximize-expr], and @racket[guarantee-expr] are removed from the global @tech["assertion store"] once
-  the query returns.  As a result, 
-  @racket[optimize] has no observable effect on the @tech["assertion store"]. 
-  The solver's ability to find solutions (as well as their optimality) depends on the current @tech["reasoning precision"],
-  as determined by the @racket[current-bitwidth] parameter.
+ 
+ Formally,
+ @racket[(solve expr)] searches for an optimal model of the formula
+ @racket[(vc-assumes #, @var{P})] ∧ @racket[(vc-asserts #, @var{P})] ∧
+ @racket[(vc-assumes #, @var{Q})] ∧ @racket[(vc-asserts #, @var{Q})],
+ where @var{P} is the verification condition before the
+ evaluation of @racket[expr], @var{Q} is the verification condition
+ generated by evaluating @racket[expr], the cost terms @racket[min-expr] are
+ minimized, and the cost terms @racket[max-expr] are maximized.
+
+ The @racket[optimize] query does not retain the
+ assumptions and assertions generated by @racket[expr],
+ but it does retain the updates to @racket[(vc)], if any,
+ produced by evaluating @racket[min-expr] and @racket[max-expr]. In other words,
+ @racket[(optimize #:minimize min-expr #:maximize max-expr #:guarantee expr)] is
+ equivalent to
+ @racket[(let ([v min-expr] [w max-expr]) (optimize #:minimize v #:maximize w #:guarantee expr))],
+ where @racket[v] and @racket[w] are fresh variables.
   
   @examples[#:eval rosette-eval
-  (code:line (current-bitwidth #f) (code:comment "use infinite-precision arithmetic"))
   (define-symbolic x y integer?)
-  (assert (< x 2))
-  (code:line (asserts)   (code:comment "assertion added to the store")) 
-  (define sol
-    (optimize #:maximize (list (+ x y))
-              #:guarantee (assert (< (- y x) 1))))
-  (code:line (asserts)   (code:comment "assertion store same as before"))
-  (code:line (evaluate x sol) (code:comment "x + y is maximal at x = 1"))
-  (code:line (evaluate y sol) (code:comment "and y = 1"))]
+  (code:comment "This query maximizes x + y while ensuring that y - x < 1 whenever x < 2:")
+  (optimize
+   #:maximize (list (+ x y))
+   #:guarantee
+   (begin
+     (assume (< x 2))
+     (assert (< (- y x) 1))))]
 }
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @(rosette-eval '(current-bitwidth 5))
 
-@section{Debugging}
-
-@defmodule[rosette/query/debug #:use-sources (rosette/query/debug)]
-
-@defform[(define/debug head body ...)
-         #:grammar
-         ([head id (id ...)])]{
-  Defines a procedure or an expression, and marks it as a candidate for debugging.  
-  When a @racket[debug] query is applied to a failing execution, 
-  forms that are not marked in this way are considered 
-  correct.  The solver will apply the debugging algorithm only to 
-  expressions and procedures marked as potentially faulty using 
-  @racket[define/debug].
-}
-
-@defform[(debug [type ...+] expr)
-         #:contracts
-         ([type (and/c solvable? type? (not/c function?))])]{
-Searches for a minimal set of @racket[define/debug] expressions of 
-the given @tech["solvable type"](s) that are collectively responsible for the observed failure of @racket[expr]. 
-If no expressions of the specified types are relevent to the failure, an error is thrown.  The 
-returned expressions, if any, are called a minimal unsatisfiable core. The core expressions 
-are relevant to the observed failure in that preventing the failure requries modifying at least one 
-core expression. In particular, if all of the non-core expressions were replaced with 
-fresh constants created using @racket[define-symbolic*], @racket[(solve expr)] would still fail.  It 
-can only execute successfully if at least one of the core expressions is also
-replaced with a fresh constant. See the @seclink["ch:essentials"]{Essentials} chapter for example uses of
-the @racket[debug] form.}
-
 @section[#:tag "sec:reasoning-precision"]{Reasoning Precision}
 
 @defparam[current-bitwidth k (or/c #f positive-integer?)
@@ -320,21 +479,28 @@ the @racket[debug] form.}
  #:eval rosette-eval
  (define-symbolic x y real?)
  (define-symbolic f (~> real? real?))
- (current-bitwidth 5)  
- (code:line (solve (assert (= x 3.5)))              (code:comment "3.5 = 3 under 5-bit semantics"))
- (code:line (solve (assert (= x 64)))               (code:comment "0 = 64 under 5-bit semantics"))
+ (code:line (current-bitwidth 5)                    (code:comment "Use 5 bits for integers and reals."))
+ (code:line (solve (assert (= x 3.5)))              (code:comment "3.5 = 3 under 5-bit semantics."))
+ (code:line (solve (assert (= x 64)))               (code:comment "0 = 64 under 5-bit semantics,"))
  (code:line (solve (assert (and (= x 64) (= x 0)))) (code:comment "leading to counterintuitive results."))
- (code:line (solve (assert (forall (list x) (= x (+ x y)))))  (code:comment "Quantifiers are not supported,"))
- (code:line (solve (assert (= x (f x))))  (code:comment "and neither are uninterpreted functions."))
- (current-bitwidth #f)
- (code:line (solve (assert (= x 3.5))) (code:comment "Infinite-precision semantics produces expected results."))
+ (eval:alts
+  (solve                                  (code:comment "Quantifiers are not supported,")
+   (assert (forall (list x) (= x (+ x y)))))
+  (eval:error (solve (assert (forall (list x) (= x (+ x y)))))))
+ (eval:alts
+  (solve                                  (code:comment "and neither are uninterpreted functions.")
+   (assert (= x (f x))))  
+  (eval:error (solve (assert (= x (f x))))))
+ (code:line (current-bitwidth #f)                   (code:comment "Use infinite-precision semantics ..."))
+ (code:line (solve (assert (= x 3.5)))              (code:comment "to obtain the expected results."))
  (solve (assert (= x 64)))
  (solve (assert (and (= x 64) (= x 0))))
- (code:line (solve (assert (forall (list x) (= x (+ x y)))))  (code:comment "Quantifiers work, and"))
+ (solve                                  (code:comment "Quantifiers work, and")
+  (assert (forall (list x) (= x (+ x y)))))
  (code:line (solve (assert (= x (f x))))            (code:comment "so do uninterpreted functions."))
- (code:line (define-symbolic i j integer?) (code:comment "But nonlinear integer arithmetic is undecidable."))
- (solve
-  (begin
+ (define-symbolic i j integer?)
+ (solve                                  (code:comment "But nonlinear integer arithmetic")
+  (begin                                 (code:comment "is undecidable.")
     (assert (> i 0))
     (assert (> j 0))
     (assert (or (= (/ i j) 2) (= (/ j i) 2)))))]

rosette/guide/scribble/libs/bvmul2.rkt

@@ -0,0 +1,197 @@
+#lang rosette
+
+(require rosette/lib/synthax rosette/guide/scribble/util/demo)
+
+(provide bvmul2_?? bvmul2_choose bvmul2_bitfast
+         bvsdiv2_bitcmp bvsdiv2_bvcmp bvsdiv2_bvcmp*)
+
+(define (bvmul2_?? x) 
+  (bvshl x (?? (bitvector 8))))
+
+(define (bvmul2_choose x)
+  ((choose bvshl bvashr bvlshr) x (?? (bitvector 8))))
+
+(define-grammar (bitfast y)
+  [expr
+   (choose y (?? (bitvector 8))
+           ((bop) (expr) (expr)))]
+  [bop
+   (choose bvshl bvashr bvlshr
+           bvand bvor bvxor
+           bvadd bvsub)])
+
+(define (bvmul2_bitfast x)
+  (bitfast x #:depth 2))
+
+(define-grammar (bitcmp y)
+  [cmp
+   (choose
+    ((op) (bitfast y) (bitfast y))
+    (and (cmp) (cmp)))]
+  [op
+   (choose
+    bvult bvule
+    bvslt bvsle)])
+
+(define (bvsdiv2_bitcmp x)
+  (if (bitcmp x)
+      (bitfast x)
+      (bitfast x)))
+
+(define (bvsdiv2 x)
+  (if (bvsge x (bv 0 8))
+      (bvlshr x (bv 1 8))
+      (bvadd (bvand x (bv 1 8))
+             (bvashr x (bv 1 8)))))
+
+(define-grammar (bvcmp xs)
+  [cmp
+   (choose
+    ((op) xs xs)
+    (and (cmp) (cmp)))]
+  [op
+   (choose
+    bvult bvule
+    bvslt bvsle)])
+
+(define (bvsdiv2_bvcmp x)
+  (if (bvcmp (bitfast x))
+      (bitfast x)
+      (bitfast x)))
+   
+
+(define (bveq_sketch x y)
+  (bvcmp (choose x y) #:depth 2))
+
+
+(define-grammar (bvcmp* xs)
+  [cmp
+   (choose
+    ((op) (arg) (arg))
+    (and (cmp) (cmp)))]
+  [op
+   (choose
+    bvult bvule
+    bvslt bvsle)]
+  [arg xs])
+
+(define (bveq_sketch* x y)
+  (bvcmp* (choose x y) #:depth 2))
+
+(define (bvsdiv2_bvcmp* x)
+  (if (bvcmp* (bitfast x))
+      (bitfast x)
+      (bitfast x)))
+
+(define-symbolic x (bitvector 8))
+
+
+(define-demo ??-demo
+  (demo (bvmul2_?? (bv 1 8)))
+  (demo (bvmul2_?? (bv 3 8)))
+
+  (demo (bvmul2_?? x))
+  (demo (equal? (bvmul2_?? x) (bvmul2_?? x)))
+
+  (define sol
+    (synthesize
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvmul2_?? x) (bvmul x (bv 2 8))))))
+
+  (demo sol)
+
+  (demo (print-forms sol)))
+
+(define-demo choose-demo
+  (demo (bvmul2_choose (bv 1 8)))
+  (demo (bvmul2_choose (bv 3 8)))
+
+  (demo (bvmul2_choose x))
+  (demo (equal? (bvmul2_choose x) (bvmul2_choose x)))
+  (clear-vc!)
+
+  (define sol
+    (synthesize
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvmul2_choose x) (bvmul x (bv 2 8))))))
+
+  (demo sol)
+
+  (demo (print-forms sol)))
+
+(define-demo grammar-demo
+  
+  (demo (bvmul2_bitfast x))
+  (demo (equal? (bvmul2_bitfast x) (bvmul2_bitfast x)))
+  (clear-vc!)
+  
+  (define sol
+    (synthesize
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvmul2_bitfast x) (bvmul x (bv 2 8))))))
+
+  (demo sol)
+
+  (demo (print-forms sol)))
+
+(define-demo grammar-with-grammar-hole-demo
+  
+  (clear-vc!)
+
+  (current-grammar-depth 2)
+  (define sol
+    (synthesize
+     #:forall (list x)
+     #:guarantee
+     (assert (equal? (bvsdiv2_bitcmp x) (bvsdiv x (bv 2 8))))))
+
+  (demo (print-forms sol)))
+
+(define-demo grammar-with-argument-choose-hole-demo
+  
+  (clear-vc!)
+
+  (define-symbolic x y (bitvector 8))
+
+  (current-grammar-depth 2)
+  
+  (demo
+   (synthesize
+    #:forall (list x y)
+    #:guarantee
+    (assert (equal? (bveq_sketch x y) (bveq x y)))))
+
+  (demo
+   (print-forms
+    (synthesize
+     #:forall (list x y)
+     #:guarantee
+     (assert (equal? (bveq_sketch* x y) (bveq x y)))))))
+
+(define-demo grammar-with-argument-bitfast-hole-demo
+  
+  (clear-vc!)
+
+  (current-grammar-depth 2)
+  
+  (demo
+   (synthesize
+    #:forall (list x)
+    #:guarantee
+    (assert (equal? (bvsdiv2_bvcmp x) (bvsdiv x (bv 2 8))))))
+
+  (demo
+   (print-forms
+    (synthesize
+     #:forall (list x)
+     #:guarantee
+     (assert (equal? (bvsdiv2_bvcmp* x) (bvsdiv x (bv 2 8))))))))
+
+(module+ main
+  (??-demo)
+  (choose-demo)
+  (grammar-demo)
+  (grammar-with-grammar-hole-demo)
+  (grammar-with-argument-choose-hole-demo)
+  (grammar-with-argument-bitfast-hole-demo))
+

rosette/guide/scribble/libs/calc-lang.rkt

@@ -0,0 +1,48 @@
+#lang rosette
+
+(require rosette/lib/angelic rosette/lib/destruct)
+
+
+(define BV (bitvector 8))
+
+(struct Add (arg) #:transparent)
+(struct Mul (arg) #:transparent)
+(struct Sqr ()    #:transparent)
+
+(define (interpret prog [acc (bv 0 BV)])
+  (if (null? prog)
+      acc
+      (interpret
+       (cdr prog)
+       (destruct (car prog)
+         [(Add v) (bvadd acc v)]
+         [(Mul v) (bvmul acc v)]
+         [(Sqr)   (bvmul acc acc)]
+         [_       acc]))))
+
+(define (inst*)
+  (define-symbolic* arg BV)
+  (choose* (Add arg) (Mul arg) (Sqr)))
+
+(define (prog* n)
+  (if (<= n 0)
+      (list)
+      (cons (inst*) (prog* (- n 1)))))
+
+(define-symbolic acc BV)
+
+(define prog (prog* 3))
+
+(define sol
+  (synthesize
+   #:forall (list acc)
+   #:guarantee
+   (assert
+    (equal? (interpret prog acc)
+            (bvsub (bvmul (bv 3 BV) acc acc) (bv 1 BV))))))
+
+(evaluate prog sol)
+  
+   
+ 
+      

rosette/guide/scribble/libs/libraries.scrbl

@@ -4,7 +4,7 @@
 
 @title[#:tag "ch:libraries" #:style 'toc]{Libraries}
 
-Chapters @seclink["ch:getting-started"]{1}-@seclink["ch:programmer-defined-datatypes"]{5} introduce the basic constructs and datatypes for programming in Rosette. This chapter describes the parts of the core Racket libraries (e.g., I/O procedures) that are exported by @racket[rosette/safe], as well as Rosette libraries that provide additional facilities for solver-aided development.
+Chapters @seclink["ch:getting-started"]{1}-@seclink["ch:programmer-defined-datatypes"]{5} introduce the basic constructs and datatypes for programming in Rosette. This chapter describes the parts of the core Racket libraries (e.g., I/O procedures) that are exported by @racketmodname[rosette/safe], as well as Rosette libraries that provide additional facilities for solver-aided development.
 
 @[table-of-contents]
 

rosette/guide/scribble/libs/libs-log.txt

@@ -1,86 +1,14 @@
 ;; This file was created by make-log-based-eval
 ((require rosette/lib/synthax) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (div2 x)
-   ((choose bvshl bvashr bvlshr bvadd bvsub bvmul) x (?? (bitvector 8))))
+((require (only-in rosette/guide/scribble/util/demo print-forms-alt))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((define-symbolic i (bitvector 8))
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_??))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-('(define (div2 x) (bvlshr x (bv 1 8)))
- ((3) 0 () 0 () () (q values (define (div2 x) (bvlshr x (bv 1 8)))))
- #""
- #"")
-((code:comment "Defines a grammar for boolean expressions")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((code:comment "in negation normal form (NNF).")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((define-synthax
-  (nnf x y depth)
-  #:base
-  (choose x (! x) y (! y))
-  #:else
-  (choose
-   x
-   (! x)
-   y
-   (! y)
-   ((choose && ||) (nnf x y (- depth 1)) (nnf x y (- depth 1)))))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((code:comment "The body of nnf=> is a hole to be filled with an")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((code:comment "expression of depth (up to) 1 from the NNF grammar.")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((define (nnf=> x y) (nnf x y 1))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-(`(define (nnf=> x y) (,|| (! x) y))
+((bvmul2_?? (bv 1 8))
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -89,71 +17,44 @@
   0
   ()
   ()
-  (c values c (c define c (q nnf=> x y) c (c (0 (u . "||")) q (! x) y))))
+  (c values c (0 (u . "(bvshl (bv #x01 8) ??:bvmul2:9:12)\n"))))
  #""
  #"")
-((code:comment "A grammar for linear arithmetic.")
+((bvmul2_?? (bv 3 8))
  ((3)
-  0
-  ()
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
   0
   ()
   ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
+  (c values c (0 (u . "(bvshl (bv #x03 8) ??:bvmul2:9:12)\n"))))
  #""
  #"")
-((define-synthax LA (((_ e ...) (+ (* e (??)) ...))))
+((define-symbolic x (bitvector 8))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((code:comment "The following query has no solution because (??) in")
+((bvmul2_?? x)
  ((3)
-  0
-  ()
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
   0
   ()
   ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((code:comment "(LA e ...) generates a single integer hole that is")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((code:comment "shared by all e passed to LA, in this case x and y.")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((define-symbolic* x y integer?)
- ((3) 0 () 0 () () (c values c (void)))
+  (c values c (0 (u . "(bvshl x ??:bvmul2:9:12)\n"))))
  #""
  #"")
+((equal? (bvmul2_?? x) (bvmul2_?? x)) ((3) 0 () 0 () () (q values #t)) #"" #"")
 ((define sol
    (synthesize
     #:forall
-    (list x y)
+    (list x)
     #:guarantee
-    (assert (= (LA x y) (+ (* 2 x) y)))))
+    (assert (equal? (bvmul2_?? x) (bvmul x (bv 2 8))))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
@@ -166,135 +67,22 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(model\n [??:bvmul2:9:12 (bv #x01 8)])\n"))))
  #""
  #"")
-((code:comment "The following query has a solution because the second")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvmul2_?? x) (bvshl x (bv #x01 8)))\n"
  #"")
-((code:comment "clause of LA2 creates two independent (??) holes.")
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   exn
-   "code:comment: undefined;\n cannot reference an identifier before its definition\n  in module: 'program"))
- #""
- #"")
-((define-synthax
-  LA2
-  (((_ e) (* e (??))) ((_ e1 e2) (+ (* e1 (??)) (* e2 (??))))))
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_choose))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((define sol2
-   (synthesize
-    #:forall
-    (list x y)
-    #:guarantee
-    (assert (= (LA2 x y) (+ (* 2 x) y)))))
+((define-symbolic x (bitvector 8))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-('(define sol
-    (synthesize
-     #:forall
-     (list x y)
-     #:guarantee
-     (assert (= (+ (* x 2) (* y 1)) (+ (* 2 x) y)))))
- ((3)
-  0
-  ()
-  0
-  ()
-  ()
-  (q
-   values
-   (define sol
-     (synthesize
-      #:forall
-      (list x y)
-      #:guarantee
-      (assert (= (+ (* x 2) (* y 1)) (+ (* 2 x) y)))))))
- #""
- #"")
-((require rosette/lib/angelic) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define (static) (choose 1 2 3))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define (dynamic) (choose* 1 2 3))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((static)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c
-   values
-   c
-   (0 (u . "(ite 0$choose:eval:27:0 1 (ite 1$choose:eval:27:0 2 3))"))))
- #""
- #"")
-((static)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c
-   values
-   c
-   (0 (u . "(ite 0$choose:eval:27:0 1 (ite 1$choose:eval:27:0 2 3))"))))
- #""
- #"")
-((dynamic)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (0 (u . "(ite xi?$0 1 (ite xi?$1 2 3))"))))
- #""
- #"")
-((dynamic)
- ((3)
-  1
-  (((lib "rosette/guide/scribble/util/lifted.rkt")
-    .
-    deserialize-info:opaque-v0))
-  0
-  ()
-  ()
-  (c values c (0 (u . "(ite xi?$2 1 (ite xi?$3 2 3))"))))
- #""
- #"")
-((equal? (static) (static)) ((3) 0 () 0 () () (q values #t)) #"" #"")
-((equal? (dynamic) (dynamic))
+((bvmul2_choose x)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -307,6 +95,250 @@
    values
    c
    (0
-    (u . "(= (ite xi?$4 1 (ite xi?$5 2 3)) (ite xi?$6 1 (ite xi?$7 2 3)))"))))
+    (u
+     .
+     "(ite*\n (⊢ 0$choose:bvmul2:12:4 (bvshl x ??:bvmul2:12:35))\n (⊢\n  (&& 1$choose:bvmul2:12:4 (! 0$choose:bvmul2:12:4))\n  (bvashr x ??:bvmul2:12:35))\n (⊢\n  (&& (! 0$choose:bvmul2:12:4) (! 1$choose:bvmul2:12:4))\n  (bvlshr x ??:bvmul2:12:35)))\n\n"))))
+ #""
+ #"")
+((equal? (bvmul2_choose x) (bvmul2_choose x))
+ ((3) 0 () 0 () () (q values #t))
+ #""
+ #"")
+((define sol
+   (synthesize
+    #:forall
+    (list x)
+    #:guarantee
+    (assert (equal? (bvmul2_choose x) (bvmul x (bv 2 8))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+(sol
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(model\n [0$choose:bvmul2:12:4 #t]\n [1$choose:bvmul2:12:4 #f]\n [??:bvmul2:12:35 (bv #x01 8)])\n\n"))))
+ #""
+ #"")
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvmul2_choose x) (bvshl x (bv #x01 8)))\n"
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-grammar
+  (bitfast y)
+  (expr (choose y (?? (bitvector 8)) ((bop) (expr) (expr))))
+  (bop (choose bvshl bvashr bvlshr bvand bvor bvxor bvadd bvsub)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_bitfast))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic x (bitvector 8))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((begin0 (equal? (bvmul2_bitfast x) (bvmul2_bitfast x)) (clear-vc!))
+ ((3) 0 () 0 () () (q values #t))
+ #""
+ #"")
+((define sol
+   (synthesize
+    #:forall
+    (list x)
+    #:guarantee
+    (assert (equal? (bvmul2_bitfast x) (bvmul x (bv 2 8))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvmul2_bitfast x) (bvshl x (bv #x01 8)))\n"
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-grammar
+  (bitcmp y)
+  (cmp (choose ((op) (bitfast y) (bitfast y)) (and (cmp) (cmp))))
+  (op (choose bvult bvule bvslt bvsle)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bitcmp))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic x (bitvector 8))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((current-grammar-depth 2) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define sol
+   (synthesize
+    #:forall
+    (list x)
+    #:guarantee
+    (assert (equal? (bvsdiv2_bitcmp x) (bvsdiv x (bv 2 8))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvsdiv2_bitcmp x)\n  (if (and (bvult x (bv #x81 8)) (bvsle (bv #x23 8) (bv #x72 8)))\n    (bvashr x (bv #x01 8))\n    (bvadd (bvashr x (bv #x01 8)) (bvand (bv #x01 8) x))))\n"
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-grammar
+  (bvcmp xs)
+  (cmp (choose ((op) xs xs) (and (cmp) (cmp))))
+  (op (choose bvult bvule bvslt bvsle)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bvcmp))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic x (bitvector 8))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((current-grammar-depth 2) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((synthesize
+  #:forall
+  (list x)
+  #:guarantee
+  (assert (equal? (bvsdiv2_bvcmp x) (bvsdiv x (bv 2 8)))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((define-grammar
+  (bvcmp* xs)
+  (cmp (choose ((op) (arg) (arg)) (and (cmp) (cmp))))
+  (op (choose bvult bvule bvslt bvsle))
+  (arg xs))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bvcmp*))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define-symbolic x (bitvector 8))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((current-grammar-depth 2) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define sol
+   (synthesize
+    #:forall
+    (list x)
+    #:guarantee
+    (assert (equal? (bvsdiv2_bvcmp* x) (bvsdiv x (bv 2 8))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((print-forms-alt sol)
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(define (bvsdiv2_bvcmp* x)\n  (if (bvult x (bv #x81 8))\n    (bvashr (bvashr x (bv #x01 8)) (bv #x00 8))\n    (bvashr (bvadd x (bv #x01 8)) (bvsub (bv #x49 8) (bv #x48 8)))))\n"
+ #"")
+((require rosette/lib/angelic rosette/lib/destruct)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define BV (bitvector 8)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((struct Add (arg) #:transparent)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((struct Mul (arg) #:transparent)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((struct Sqr () #:transparent) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define (interpret prog (acc (bv 0 BV)))
+   (if (null? prog)
+     acc
+     (interpret
+      (cdr prog)
+      (destruct
+       (car prog)
+       ((Add v) (bvadd acc v))
+       ((Mul v) (bvmul acc v))
+       ((Sqr) (bvmul acc acc))
+       (_ acc)))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (inst*) (define-symbolic* arg BV) (choose* (Add arg) (Mul arg) (Sqr)))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (prog* n) (if (<= n 0) (list) (cons (inst*) (prog* (- n 1)))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic acc BV) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((define prog (prog* 3)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(prog
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "'((union\n   [xi?$1 #(struct:Add arg$0)]\n   [(&& xi?$2 (! xi?$1)) #(struct:Mul arg$0)]\n   [(&& (! xi?$1) (! xi?$2)) #(struct:Sqr)])\n  (union\n   [xi?$4 #(struct:Add arg$3)]\n   [(&& xi?$5 (! xi?$4)) #(struct:Mul arg$3)]\n   [(&& (! xi?$4) (! xi?$5)) #(struct:Sqr)])\n  (union\n   [xi?$7 #(struct:Add arg$6)]\n   [(&& xi?$8 (! xi?$7)) #(struct:Mul arg$6)]\n   [(&& (! xi?$7) (! xi?$8)) #(struct:Sqr)]))\n\n"))))
+ #""
+ #"")
+((define sol
+   (synthesize
+    #:forall
+    (list acc)
+    #:guarantee
+    (assert
+     (equal?
+      (interpret prog acc)
+      (bvsub (bvmul (bv 3 BV) acc acc) (bv 1 BV))))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((evaluate prog sol)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list (Sqr) (Add (bv #x55 8)) (Mul (bv #x03 8)))\n"))))
  #""
  #"")

rosette/guide/scribble/libs/racket-libs.scrbl

@@ -17,5 +17,4 @@ Rosette exports the following facilities from the core Racket libraries:
 
 These facilities are safe to use in Rosette programs, even in the presence of symbolic values, assertions, and solver-aided queries. They are not, however, @tech[#:key "lifted constructs"]{lifted}:  if their Racket implementation expects a concrete value of a given type, they will fail when given a symbolic value.  These constructs are safe to use in the sense that they will fail in a predictable fashion, according to their concrete Racket specification, instead of causing the enclosing Rosette program to exhibit unexpected behavior.
 
-The @racket[rosette/safe] language allows programs to import arbitrary Racket code using the standard @racket[require] mechanism.  This is strongly discouraged, however, unless the use of such code obeys the restrictions outlined in the @seclink["ch:unsafe"]{Chapter 8}.  Violating these restrictions may lead to incorrect program behavior, crashes, and loss of data (for programs that perform external side-effects, such as writing to files).  In other words, arbitrary Racket code is, by default, unsafe to use.
-
+The @racketmodname[rosette/safe] language allows programs to import arbitrary Racket code using the standard @racket[require] mechanism.  This is strongly discouraged, however, unless the use of such code obeys the restrictions outlined in the @seclink["ch:unsafe"]{Chapter 8}.  Violating these restrictions may lead to incorrect program behavior, crashes, and loss of data (for programs that perform external side-effects, such as writing to files).  In other words, arbitrary Racket code is, by default, unsafe to use.

rosette/guide/scribble/libs/rosette-lib-test.rkt

@@ -1,72 +0,0 @@
-#lang rosette
-
-(require rosette/lib/synthax)
-
-(define (div2 x) ([choose bvshl bvashr bvlshr bvadd bvsub bvmul] x (?? (bitvector 8))))
-(define-symbolic i (bitvector 8))
-(define m1
- (synthesize #:forall (list i)
-             #:guarantee (assert (equal? (div2 i) (bvudiv i (bv 2 8))))))
-(print-forms m1)
-(generate-forms m1)
-
-(define-synthax (nnf x y depth)
-  #:base (choose x (! x) y (! y))
-  #:else (choose
-          x (! x) y (! y)
-          ((choose && ||) (nnf x y (- depth 1))
-                          (nnf x y (- depth 1)))))
-
-(define (nnf=> x y) (nnf x y 1))
-
-(define-symbolic a b boolean?)
-
-(print-forms
-  (synthesize
-   #:forall (list a b)
-   #:guarantee (assert (equal? (=> a b) (nnf=> a b)))))
-
-; A grammar for linear arithmetic.
-(define-synthax LA
- ([(_ e ...) (+ (* e (??)) ...)]))
- 
-; The following query has no solution because (??) in
-; (LA e ...) generates a single integer hole that is
-; shared by all e passed to LA, in this case x and y.
-(define-symbolic* x y integer?)
-
-(define sol
-  (synthesize
-   #:forall (list x y)
-   #:guarantee (assert (= (LA x y) (+ (* 2 x) y)))))
-
-sol
-
-; The following query has a solution because the second
-; clause of LA2 creates two independent (??) holes.
-(define-synthax LA2
-  ([(_ e) (* e (??))]
-   [(_ e1 e2) (+ (* e1 (??)) (* e2 (??)))]))
- 
-(define sol2
-  (synthesize
-   #:forall (list x y)
-   #:guarantee (assert (= (LA2 x y) (+ (* 2 x) y)))))
-
-(print-forms sol2)
-
-#|
-(define-synthax [shift terminal ... k]
-  #:assert (>= k 0)
-  [choose
-   terminal ... (??)
-   ([choose >> << >>>] (shift terminal ... (- k 1))
-                       (shift terminal ... (- k 1)))])
-
-(define (div2mul4 x) (shift x 2))
-
-(define m2
- (synthesize #:forall (list i)
-             #:assume (assert (>= i 0))
-             #:guarantee (assert (= (div2mul4 i) (* 4 (quotient i 2))))))
-(print-forms m2)|#

rosette/guide/scribble/libs/rosette-libs.scrbl

@@ -1,159 +1,387 @@
 #lang scribble/manual
 
 @(require (for-label 
-           rosette/base/form/define rosette/solver/solution rosette/query/query rosette/query/eval 
+           rosette/base/form/define rosette/solver/solution rosette/query/query 
            rosette/base/core/term rosette/lib/angelic
-           (except-in rosette/query/debug assert )
-           (only-in rosette/lib/synthax ?? choose define-synthax generate-forms print-forms)
-           (only-in rosette/base/core/safe assert)
-           (only-in rosette/base/base function? bitvector bvshl bvashr bvlshr bvadd bvsub bvmul)
-           rosette/lib/render
-           racket (only-in pict pict?))
-          scribble/core scribble/html-properties scribble/eval racket/sandbox  racket/runtime-path
+           rosette/lib/synthax 
+           (only-in rosette/base/base assert function? bitvector
+                    bvshl bvashr bvlshr bvadd bvsub bvmul bvsdiv
+                    bvand bvor bvxor bvult bvule bvslt bvsle)
+           (only-in rosette/lib/destruct destruct)
+           racket)
+          scribble/core scribble/html-properties scribble/examples racket/sandbox  racket/runtime-path
           "../util/lifted.rkt")
 
 
 @(define-runtime-path root ".")
 @(define rosette-eval (rosette-log-evaluator (logfile root "libs-log")))
 
+
 @title[#:tag "sec:rosette-libs"]{Solver-Aided Libraries}
 
-In principle, solver-aided programming requires only symbolic values and the basic constructs described in Chapter @seclink["ch:syntactic-forms:rosette"]{3}.  In practice, however, it is often convenient to work with richer constructs, which are built on top of these primitives.  Rosette ships with three libraries that provide such constructs, as well as utility procedures for turning the results of synthesis and debugging queries into code.
+In principle, solver-aided programming requires only
+symbolic values and the basic constructs described in
+Chapter @seclink["ch:syntactic-forms:rosette"]{3}. In
+practice, however, it is often convenient to work with
+richer constructs, which are built on top of these
+primitives. Rosette ships with two libraries that provide
+such constructs, as well as utility procedures for turning
+the results of synthesis queries into code.
 
 
 @section{Synthesis Library}
 
-@defmodule[rosette/lib/synthax #:use-sources (rosette/lib/synthax/core rosette/lib/synthax/form)]
+@defmodule[rosette/lib/synthax #:use-sources (rosette/lib/synthax)]
 
 @(rosette-eval '(require rosette/lib/synthax))
+@(rosette-eval '(require (only-in rosette/guide/scribble/util/demo print-forms-alt)))
+
 @defform[(?? maybe-type)
          #:grammar [(maybe-type (code:line)
                                 type-expr)]
          #:contracts ([type-expr (and/c solvable? type? (not/c function?))])                                  
          ]{
-Introduces a @tech{hole} into a program---a placeholder for a concrete constant of the given type.
-The default type for holes, if one is not provided, is @racket[integer?]. 
-Chapter @seclink["sec:synthesize"]{2.3.3} shows an example of using integer holes to @tech{sketch}
-a factored polynomial function, which is then completed with the help of a @racket[synthesize]  query.  
-The @racket[(??)] construct @seclink["sec:symbolic-constants"]{creates} 
-and returns a fresh symbolic constant of type @racket[type-expr] (or @racket[integer?]).
+           
+ Introduces a constant @tech{hole} into a program---a
+ placeholder for a concrete constant of the given type. The
+ default value for @racket[type-expr], if one is not
+ provided, is @racket[integer?]. The @racket[??] construct
+ @seclink["sec:symbolic-constants"]{creates} and returns a
+ distinct symbolic constant of type @racket[type-expr].
+
+ When used in a recursive @racketlink[define-grammar]{grammar definition},
+ a @racket[??] hole generates a fresh constant
+ every time it is evaluated, similarly to
+ @racket[define-symbolic*]. Otherwise, a @racket[??] hole
+ always generates the same constant, similarly to
+ @racket[define-symbolic].
+
+ See also @racket[define-grammar].
+
+@examples[#:eval rosette-eval #:no-prompt
+(code:comment "Uses a ?? hole to sketch a procedure for multiplying")
+(code:comment "an 8-bit number by 2 using a constant left shift.")
+(eval:alts
+(define (bvmul2_?? x) 
+  (bvshl x (?? (bitvector 8))))
+(require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_??)))]
+@examples[#:eval rosette-eval #:label #f
+(code:comment "bvmul2_?? hole always returns the same constant:")
+(bvmul2_?? (bv 1 8))
+(bvmul2_?? (bv 3 8))
+
+(define-symbolic x (bitvector 8))
+(bvmul2_?? x)
+(equal? (bvmul2_?? x) (bvmul2_?? x))
+
+(code:comment "Use synthesis to fill the hole with a constant:")
+(define sol
+  (synthesize
+   #:forall (list x)
+   #:guarantee (assert (equal? (bvmul2_?? x) (bvmul x (bv 2 8))))))
+sol
+(code:comment "Save bvmul2_?? to a file before calling print-forms.")
+(eval:alts (print-forms sol) (print-forms-alt sol))
+]
 }
 
+
 @defform[(choose expr ...+)]{
-Introduces a choice @tech{hole} into a program---a placeholder to be filled with one of the given expressions. 
-This construct defines @var[n]-1 fresh boolean constants and uses them to conditionally select one of the @var[n] 
-provided expressions.    
-@examples[#:eval rosette-eval
-(define (div2 x)
-  ([choose bvshl bvashr bvlshr bvadd bvsub bvmul] x (?? (bitvector 8))))
-(define-symbolic i (bitvector 8))
+                             
+ Introduces a choice @tech{hole} into a program---a
+ placeholder to be filled with one of the given expressions.
+ This construct defines @var[n]-1 distinct boolean constants
+ and uses them to conditionally select one of the @var[n]
+ provided expressions.
+
+ When used in a recursive @racketlink[define-grammar]{grammar definition},
+ a @racket[choose] hole generates fresh selector
+ constants and may select a different expression every time
+ it is evaluated. Otherwise, a @racket[choose] hole generates
+ the same constants and makes the same selection every time.
+
+ See also @racket[choose*] and @racket[define-grammar].
+
+@examples[#:eval rosette-eval  #:no-prompt
+(code:comment "Uses a chooose hole to sketch a procedure for multiplying")
+(code:comment "an 8-bit number by 2 using a constant shift.")
 (eval:alts
-(print-forms 
- (synthesize #:forall (list i)
-             #:guarantee (assert (equal? (div2 i) (bvudiv i (bv 2 8))))))
-'(define (div2 x) (bvlshr x (bv #x01 8))))] 
-}
+(define (bvmul2_choose x)
+  ((choose bvshl bvashr bvlshr) x (?? (bitvector 8))))
+(require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_choose)))]
+@examples[#:eval rosette-eval #:label #f
+(code:comment "bvmul2_choose holes always generate the same constants:")
+(define-symbolic x (bitvector 8))
+(bvmul2_choose x)
+(equal? (bvmul2_choose x) (bvmul2_choose x))
 
-@defform*[((define-synthax id
-             ([pattern expr] ...+))
-           (define-synthax (id terminal ... k)
-             #:base base-expr
-             #:else else-expr))]{
-Defines a grammar of expressions that can be used to 
-fill holes of the form @racket[(id e ...)].  That is, writing 
-@racket[(id e ...)] introduces a @tech{hole} that is to 
-be filled with an expression from the @racket[id] grammar.
-
-The first form, @racket[(define-synthax id ([pattern expr] ...+))], 
-works like Racket's @racket[syntax-rules] macro:  it fills   
-the hole @racket[(id e ...)] with the expression @racket[expr] that
-corresponds to the first @racket[pattern] matching the hole.
-The second form, @racket[(define-synthax (id terminal ... k) #:base base-expr #:else else-expr)],
-defines a recursive grammar that is inlined a finite number of times
-to fill a hole.  The @racket[base-expr] usually chooses among
-the provided terminals,
-while the @racket[else-expr] chooses among the terminals and a set of productions.
-The hole @racket[(id e ... k)] must specify the inlining bound
-@racket[k] as an integer literal.
-
-@examples[#:eval rosette-eval
-(eval:no-prompt
- (code:comment "Defines a grammar for boolean expressions")
- (code:comment "in negation normal form (NNF).")
- (define-synthax (nnf x y depth)
-  #:base (choose x (! x) y (! y))
-  #:else (choose
-          x (! x) y (! y)
-          ((choose && ||) (nnf x y (- depth 1))
-                          (nnf x y (- depth 1))))))
-(eval:no-prompt
- (code:comment "The body of nnf=> is a hole to be filled with an")
- (code:comment "expression of depth (up to) 1 from the NNF grammar.")
- (define (nnf=> x y)
-   (nnf x y 1)))
-(define-symbolic a b boolean?)
-(eval:alts
- (print-forms
+(code:comment "Use synthesis to fill the holes:")
+(define sol
   (synthesize
-   #:forall (list a b)
-   #:guarantee (assert (equal? (=> a b) (nnf=> a b)))))
- `(define (nnf=> x y) (,|| (! x) y)))
+   #:forall (list x)
+   #:guarantee (assert (equal? (bvmul2_choose x) (bvmul x (bv 2 8))))))
+sol
+(code:comment "Save bvmul2_choose to a file before calling print-forms.")
+(eval:alts (print-forms sol) (print-forms-alt sol))
 ]
 
-Since @racket[define-synthax] uses macros to implement recursive grammars, 
-instantiating a recursive grammar with a large limit (e.g., k > 3) can cause
-long compilation times, especially if @racket[else-expr] contains many
-recursive instantiations of the grammar.
+}
 
-Note also that the  @racket[...] transformer cannot be used to create multiple  
-@racket[??] or @racket[choose] holes within a @racket[define-synthax] form.
-In particular, a given syntactic occurrence of @racket[??] or @racket[choose]
-always refers to the same hole, as shown below.
 
-@examples[#:eval rosette-eval
-(eval:no-prompt
- (code:comment "A grammar for linear arithmetic.") 
- (define-synthax LA
-  ([(_ e ...) (+ (* e (??)) ...)]))
 
- (code:comment "The following query has no solution because (??) in")
- (code:comment "(LA e ...) generates a single integer hole that is")
- (code:comment "shared by all e passed to LA, in this case x and y.")
- (define-symbolic* x y integer?)
+@defform[(define-grammar (id arg-id ...)
+           [rule-id rule-expr] ...+)]{
+                                     
+ Defines a macro for creating and filling grammar
+ @tech[#:key "hole"]{holes}. The macro uses
+ @racket[(id arg-id ...)] as the pattern for creating holes
+ and @racket[[rule-id rule-expr] ...+] as the rules for
+ filling these holes with expressions. In particular, writing
+ @racket[(id #, @var[arg-expr] ...)] creates a hole for an
+ expression derived from the grammar
+ @racket[[rule-id rule-expr] ...+], where the pattern
+ variables @racket[arg-id] are instantianted with the hole
+ arguments @racket[#, @var[arg-expr]].
+
+ Each hole defines a local scope that binds the rule names
+ @racket[rule-id] to procedures of the form
+ @racket[(lambda () ... rule-expr)]. This scope behaves like
+ @racket[letrec], so rules can refer to themselves and each
+ other via @racket[(rule-id)] to specify a recursive grammar.
+
+ For example, the following definition specifies a
+ grammar of fast bitvector expressions over one input:
+
+ @(rosette-eval '(clear-vc!))
+ @examples[#:eval rosette-eval #:label #f #:no-prompt
+ (code:line
+  (define-grammar (bitfast y)         
+    [expr                            (code:comment "<expr> :=")
+     (choose y (?? (bitvector 8))    (code:comment " y | <8-bit constant> |")
+             ((bop) (expr) (expr)))] (code:comment " ((bop) <expr> <expr>)")
+    [bop                             (code:comment "<bop>  :=")
+     (choose bvshl bvashr bvlshr     (code:comment " bvshl | bvashr | bvlshr |")
+             bvand bvor bvxor        (code:comment " bvand | bvor | bvxor | ")
+             bvadd bvsub)])          (code:comment " bvadd | bvsub"))]
+
+ By default, a grammar hole is filled by evaluating the
+ first grammar rule @racket[(#, @elem{@var{rule-id}@subscript{0}})]
+ in the hole's local scope, and limiting the call stack to include at
+ most @racket[(current-grammar-depth)] applications of the grammar rules.
+ Holes can override these defaults by providing the optional arguments  
+ @racket[#:depth n] and @racket[#:start #, @elem{@var{rule-id}@subscript{k}}], 
+ which control the call stack depth and the starting rule, respectively.
+
+ @examples[#:eval rosette-eval #:label #f #:no-prompt
+ (code:comment "Uses a bitfast hole to sketch a procedure consisting")
+ (code:comment "of a fast bitvector expression over x, created by at")
+ (code:comment "most 2 applications of the bitfast grammar rules,")
+ (code:comment "following the initial application of the (expr) rule.")
+ (eval:alts
+  (define (bvmul2_bitfast x)
+    (bitfast x #:depth 2))
+  (require (only-in rosette/guide/scribble/libs/bvmul2 bvmul2_bitfast)))]
+ 
+ Whenever a grammar hole is evaluated, its constituent
+ @racket[choose] and @racket[??] holes generate the same set
+ of constants, with each rule application generating a
+ distinct subset of this set. This allows different
+ applications of the same rule to produce different
+ components of the unique expression that fills a grammar
+ hole. 
+ 
+@examples[#:eval rosette-eval #:label #f
+ (code:comment "The choose and ?? holes that are part of the same bitfast")
+ (code:comment "hole always generate the same set of constants:")
+ (define-symbolic x (bitvector 8))
+ (eval:alts
+  (equal? (bvmul2_bitfast x) (bvmul2_bitfast x))
+  (begin0
+    (equal? (bvmul2_bitfast x) (bvmul2_bitfast x))
+    (clear-vc!)))
+    
+
  (define sol
     (synthesize
-    #:forall (list x y)
-    #:guarantee (assert (= (LA x y) (+ (* 2 x) y))))))
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvmul2_bitfast x) (bvmul x (bv 2 8))))))
 
- sol
+ (code:comment "Save bvmul2_bitfast to a file before calling print-forms.")
+ (eval:alts (print-forms sol) (print-forms-alt sol))]
 
- (eval:no-prompt
-  (code:comment "The following query has a solution because the second")
-  (code:comment "clause of LA2 creates two independent (??) holes.")
-  (define-synthax LA2
-    ([(_ e) (* e (??))]
-     [(_ e1 e2) (+ (* e1 (??)) (* e2 (??)))]))
+ Grammar rules can include grammar holes as part of their
+ definition. An included grammar hole behaves just like an
+ included @racket[choose] or @racket[??] hole: it can be
+ filled with different expressions in different applications
+ of the enclosing rule.
 
-  (define sol2
-    (synthesize
-     #:forall (list x y)
-     #:guarantee (assert (= (LA2 x y) (+ (* 2 x) y))))))
+ @(rosette-eval '(clear-vc!))
+ @examples[#:eval rosette-eval #:label #f #:no-prompt
+ (code:comment "Specifies a grammar of signed and unsigned")
+ (code:comment "comparisons of bitfast expressions.")
+ (code:line
+  (define-grammar (bitcmp y)         
+    [cmp                            
+     (choose                         (code:comment "<cmp> :=")
+      ((op) (bitfast y) (bitfast y)) (code:comment " (<op> <bitfast y> <bitfast y>) |")
+      (and (cmp) (cmp)))]            (code:comment " (and <cmp> <cmp>)")
+    [op
+     (choose                         (code:comment "<op>  :=")
+      bvult bvule                    (code:comment " bvult | bvule |")
+      bvslt bvsle)])                 (code:comment " bvslt | bvsle"))
 
+  (code:comment "Uses bitcmp and bitfast holes to sketch")
+  (code:comment "a procedure with a conditional, intended")
+  (code:comment "to implement fast signed division by 2.")
   (eval:alts
-  (print-forms sol2)
-  '(define sol
+   (define (bvsdiv2_bitcmp x)
+     (if (bitcmp x)
+         (bitfast x)
+         (bitfast x)))
+   (require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bitcmp)))]
+ @examples[#:eval rosette-eval #:label #f
+  (define-symbolic x (bitvector 8))
+  (code:line (current-grammar-depth 2) (code:comment "Set the grammar depth."))
+  (define sol
     (synthesize
-      #:forall
-      (list x y)
-      #:guarantee
-      (assert (= (+ (* x 2) (* y 1)) (+ (* 2 x) y))))))]
-}
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvsdiv2_bitcmp x) (bvsdiv x (bv 2 8))))))
+  (code:comment "Save bvsdiv2_bitcmp to a file before calling print-forms.")
+  (code:comment "Note that the solver can return any correct solution.")
+  (code:comment "In this case, there is a shorter solution that omits the")
+  (code:comment "trivially true right child from the test expression.")
+  (eval:alts (print-forms sol) (print-forms-alt sol))]
+ 
+
+ Finally, grammar holes can accept other holes as arguments.
+ Unlike included holes, argument holes are @emph{shared}
+ within the same rule. If an argument @racket[arg-id] is
+ bound to a hole @var[arg-expr], then @emph{all} occurrences
+ of @racket[arg-id] in a given rule refer to @emph{one}
+ shared @var[arg-expr] hole, which can be filled with
+ different expressions in different applications of the rule.
+ In contrast, if a rule explicitly includes @var[arg-expr]
+ multiple times, then each occurrence of @var[arg-expr]
+ creates a distinct hole. The following examples illustrate
+ the difference and show how to structure grammars to avoid
+ unwanted sharing of argument holes.
+
+ @(rosette-eval '(clear-vc!))
+ @examples[#:eval rosette-eval #:label #f #:no-prompt
+ (code:comment "This grammar is intended to take a hole xs")
+ (code:comment "as an argument and use it to define the space")
+ (code:comment "of signed and unsigned comparisons over the xs")
+ (code:comment "expressions. The grammar is the same as bitcmp")
+ (code:comment "except that it uses xs instead of (bitfast y)")
+ (code:comment "in the cmp rule.")
+ (define-grammar (bvcmp xs)
+  [cmp
+   (choose              (code:comment "Both occurrences of xs")
+    ((op) xs xs)        (code:comment "refer to a single shared")
+    (and (cmp) (cmp)))] (code:comment "hole in this rule.")
+  [op
+   (choose
+    bvult bvule
+    bvslt bvsle)])
+ (code:comment "This sketch is the same as bvsdiv2_bitcmp except")
+ (code:comment "that it replaces bitcmp with (bvcmp (bitfast x)).")
+ (eval:alts
+   (define (bvsdiv2_bvcmp x)
+     (if (bvcmp (bitfast x))
+         (bitfast x)
+         (bitfast x)))
+   (require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bvcmp)))]
+ @examples[#:eval rosette-eval #:label #f
+  (define-symbolic x (bitvector 8))
+  (current-grammar-depth 2)
+  (code:comment "There is no solution because the two xs in the")
+  (code:comment "cmp rule of the bvcmp grammar refer to the same")
+  (code:comment "hole, so it is not possible for the rule to")
+  (code:comment "create a comparison expression with different left")
+  (code:comment "and right children (comparing x to a constant).")
+  (synthesize
+    #:forall (list x)
+    #:guarantee (assert (equal? (bvsdiv2_bvcmp x) (bvsdiv x (bv 2 8)))))]
+ @examples[#:eval rosette-eval #:label #f #:no-prompt
+ (code:comment "To avoid the sharing, we refactor bvcmp to place xs into")
+ (code:comment "its own rule, arg, which is then called by cmp. ")
+ (code:comment "This works because every application of the arg rule")
+ (code:comment "can fill its sole xs hole with a different expression.")
+ (define-grammar (bvcmp* xs)
+  [cmp
+   (choose
+    ((op) (arg) (arg))
+    (and (cmp) (cmp)))]
+  [op
+   (choose
+    bvult bvule
+    bvslt bvsle)]
+  [arg xs])
+ (code:comment "This sketch is the same as bvsdiv2_bitcmp except")
+ (code:comment "that it replaces bitcmp with (bvcmp* (bitfast x)).")
+ (eval:alts
+   (define (bvsdiv2_bvcmp* x)
+     (if (bvcmp* (bitfast x))
+         (bitfast x)
+         (bitfast x)))
+   (require (only-in rosette/guide/scribble/libs/bvmul2 bvsdiv2_bvcmp*)))]
+  @(rosette-eval '(clear-vc!))
+  @examples[#:eval rosette-eval #:label #f
+  (define-symbolic x (bitvector 8))
+  (current-grammar-depth 2)
+  (code:comment "A solution exists now because the arg rule produces")
+  (code:comment "different left and right children for the comparison")
+  (code:comment "operator used in the bvsdiv2_bvcmp* conditional test.")
+  (define sol
+    (synthesize
+     #:forall (list x)
+     #:guarantee (assert (equal? (bvsdiv2_bvcmp* x) (bvsdiv x (bv 2 8))))))
+  (code:comment "Save bvsdiv2_bvcmp* to a file before calling print-forms.")
+  (eval:alts (print-forms sol) (print-forms-alt sol))]}
+
+@defform[(define-simple-grammar (id arg-id ...) body)]{
+ Defines a grammar with a single (possibly recursive) rule. Equivalent to
+ @(racketblock
+   (define-grammar (id param ...)
+     [id body]))}
+
+@defparam[current-grammar-depth n natural?
+          #:value 0]{
+                     
+ A parameter that controls the evaluation of
+ @racketlink[define-grammar]{grammar} holes. Evaluating a
+ grammar hole involves evaluating the rules of its grammar.
+ The @racket[(current-grammar-depth)] parameter controls how
+ many of these rules can appear on the call stack after the
+ start rule is evaluated. The default value of 0 allows
+ only the start rule to be evaluated, and a value of
+ @racket[n > 0] allows at most @racket[n] additional rules to
+ be added to the call stack. For best performance, keep the
+ value of this parameter as low as possible.}                   
 
 @defproc[(generate-forms [solution solution?]) (listof syntax?)]{
-Given a satisfiable @racket[solution?] to a @racket[synthesize]  query,
-returns a list of @tech{sketch} completions for that query.  
-Sketch completions can only be generated for programs that have been saved to disk.  
-}
+                                                                 
+  Given a satisfiable @racket[solution?] to a
+  @racket[synthesize] query, returns a list of @tech{sketch}
+  completions for that query. Sketch completions can only be
+  generated for programs that have been saved to disk.
+
+  This procedure cooperates with the constructs in the
+  @racketmodname[rosette/lib/synthax] library to turn solutions into
+  code. It works by scanning program files for
+  @racketlink[??]{constant}, @racketlink[choose]{choice}, and
+  @racketlink[define-grammar]{grammar} holes, and replacing
+  all identified holes with code. The code for a hole is
+  computed from the @racket[solution] bindings for the
+  symbolic constants generated by the hole. Holes are
+  identified by their original names: @racket[??],
+  @racket[choose], and any @racket[id] introduced by
+  @racket[define-grammar] or @racket[define-simple-grammar].
+  If a program uses different names for these holes (e.g., by
+  renaming them in a @racket[require] clause),
+  @racket[generate-forms] will not recognize or replace them,
+  even if the given solution has bindings for their symbolic
+  constants.}
 
 @defproc[(print-forms [solution solution?]) void?]{
   Pretty-prints the result of applying @racket[generate-forms] to the given  
@@ -164,36 +392,83 @@ Sketch completions can only be generated for programs that have been saved to di
 @section{Angelic Execution Library}
 @defmodule[rosette/lib/angelic #:use-sources (rosette/lib/angelic)]
 
-@(rosette-eval '(require rosette/lib/angelic))
 @defproc[(choose* [v any/c] ...+) any/c]{
-Non-determinstically chooses between the provided values. The difference
-between @racket[choose*] and @racket[choose] is analogous to the difference
-between @racket[define-symbolic*] and @racket[define-symbolic]:  the former
-is dynamic and the latter is static.
 
-@examples[#:eval rosette-eval
-(define (static)  (choose 1 2 3))
-(define (dynamic) (choose* 1 2 3))
-(static)
-(static)
-(dynamic)
-(dynamic)
-(equal? (static) (static))
-(equal? (dynamic) (dynamic))]
+                                         
+ Symbolically chooses one of the provided values. The
+ procedure creates @var[n]-1 fresh symbolic boolean constants
+ every time it is evaluated, and uses these constants to
+ conditionally select one of the @var[n] provided
+ expressions.
+
+ The @racket[choose*] procedure is related to the
+ @racket[choose] construct from the synthesis library.
+ Semantically, the difference between @racket[choose*] and
+ @racket[choose] is analogous to the difference between
+ @racket[define-symbolic*] and @racket[define-symbolic].
+ 
+ They also differ in how they are typically used:
+ @racket[choose] is used primarily for synthesis, while
+ @racket[choose*] is suitable for both synthesis (via the
+ @racket[synthesize] query) and angelic execution (via the
+ @racket[solve] query).
+ 
+ In the context of synthesis, @racket[choose] is used to
+ sketch programs in (a subset of) the Rosette language, and
+ @racket[choose*] can be used to sketch programs in any
+ language that has a Rosette-based interpreter.
+ 
+
+ @examples[#:eval rosette-eval #:no-prompt
+ (require rosette/lib/angelic rosette/lib/destruct)
+
+ (define BV (bitvector 8))
+ 
+ (code:comment "A toy language for programs that manipulate a")
+ (code:comment "a single storage cell by adding a constant to")
+ (code:comment "it, multiplying it by constant, and squaring it.")
+ 
+ (struct Add (arg) #:transparent)
+ (struct Mul (arg) #:transparent)
+ (struct Sqr ()    #:transparent)
+
+ (define (interpret prog [acc (bv 0 BV)])
+   (if (null? prog)
+       acc
+       (interpret
+        (cdr prog)
+        (destruct (car prog)
+          [(Add v) (bvadd acc v)]
+          [(Mul v) (bvmul acc v)]
+          [(Sqr)   (bvmul acc acc)]
+          [_       acc]))))
+
+ (code:comment "Creates a symbolic instruction (a hole) in the toy language.")
+ (define (inst*)
+  (define-symbolic* arg BV)
+  (choose* (Add arg) (Mul arg) (Sqr)))
+
+ (code:comment "Creates a toy program consisting of n symbolic instructions.")
+ (define (prog* n)
+  (if (<= n 0)
+      (list)
+      (cons (inst*) (prog* (- n 1)))))]
+ 
+ @examples[#:eval rosette-eval #:label #f
+ (define-symbolic acc BV)
+ (define prog (prog* 3))
+ prog
+ (code:comment "Complete prog so that it implements 3 * acc^2 - 1 for all acc.")
+ (define sol
+  (synthesize
+   #:forall (list acc)
+   #:guarantee
+   (assert
+    (equal? (interpret prog acc)
+            (bvsub (bvmul (bv 3 BV) acc acc) (bv 1 BV))))))
+ (evaluate prog sol)]
+
 }
 
-@section{Debugging Library}
-@defmodule[rosette/lib/render #:use-sources (rosette/lib/render)]
-
-@defproc[(render [solution solution?] [font-size natural/c 16]) pict?]{
-Given an unsatisfiable @racket[solution?] to a @racket[debug]  query, returns a 
-@racket[pict?] visualization of that solution.  The visualization displays the 
-debugged code, highlighting the faulty expressions (i.e., those in the @racket[solution]'s core) in red. 
-The optional @racket[font-size] parameter controls the size of the font used to typeset the code. 
-Visualizations can only be constructed for programs that have been saved to disk.  
-See Chapter @seclink["sec:debug"]{2.3.2} for an example of using @racket[render].
-}
-
-
 
 @(kill-evaluator rosette-eval)

rosette/guide/scribble/libs/utility-libs.scrbl

@@ -1,22 +1,109 @@
 #lang scribble/manual
 
 @(require scribble/bnf
+          scribble/example
+          scribblings/reference/match-parse
           (only-in racket/draw read-bitmap)
           (for-label
            rosette/lib/value-browser
+           rosette/lib/destruct
            (only-in racket/gui snip%)
            rosette/base/form/define
            rosette/base/core/term
-           (only-in rosette/base/base bv bitvector ~>)
+           (only-in rosette/base/base bv bitvector ~> assert)
            racket)
           scribble/core scribble/html-properties racket/runtime-path)
 
 @(define-runtime-path root ".")
+@(define the-eval (make-base-eval))
+@(the-eval '(require rosette rosette/lib/destruct))
 
 @title[#:tag "sec:utility-libs"]{Utility Libraries}
 
 The following utility libraries facilitate the development of solver-aided programs.
 
+@section{Value Destructuring Library}
+
+@defmodule[rosette/lib/destruct]
+
+@defform[(destruct val-expr [pat body ...+] ...)]{
+  Finds the first @racket[pat] that matches the result of @racket[val-expr], and evaluates the
+  corresponding @racket[body]s with bindings introduced by @racket[pat] (if any).
+  In other words, it provides a @tech[#:key "lifted constructs"]{lifted} pattern matching similar to @racket[match] with limited capabilities:
+
+  @itemlist[
+    @item{A sub-pattern is restricted to an identifier, a wildcard (@litchar{_}),
+    or an ellipsis (e.g., @litchar{...}). That is, @racket[destruct] allows value destructuring only at
+    the outermost level (nested destructuring is disallowed).}
+    @item{All binding identifiers in a clause must be unique (no duplicate binding identifiers).}
+    @item{Only patterns with lifted semantics are supported. See the grammar below for full details.}
+    @item{Side-conditioning via @racket[#:when] and the failure procedure are not supported.}
+ ]
+
+  @examples[
+  #:eval the-eval
+  (struct add (x y))
+  (struct mul (x y))
+  (define (interp v)
+    (destruct v
+      [(add x y) (+ x y)]
+      [(mul x y) (* x y)]
+      [_ (assert #f "infeasible")]))
+
+  (interp (add 3 4))
+  (interp (mul 5 6))
+
+  (define-symbolic b boolean?)
+  (interp (if b (add 3 4) (mul 5 6)))]
+
+  The grammar of @racket[pat] is as follows, where non-italicized identifiers are
+  recognized literally (i.e., not by binding).
+
+  @(parse-match-grammar "
+pat     ::= _sp                               @match anything; see details below
+         |  (LIST lvp ...)                    @match a list
+         |  (LIST-REST lvp ... _sp)           @match a list with tail
+         |  (LIST* lvp ... _sp)               @match a list with tail
+         |  (VECTOR lvp ...)                  @match a vector
+         |  (CONS _sp _sp)                    @match a pair
+         |  (BOX _sp)                         @match a box
+         |  (struct-id _sp ...)               @match a struct-id instance
+sp      ::= id                                @match anything, bind identifier
+         |  _                                 @match anything, ignore the result
+lvp     ::= (code:line _sp ooo)               @greedily match anything
+         |  _sp                               @match anything
+ooo     ::= ***                               @zero or more; *** is literal
+         |  ___                               @zero or more
+         |  ..K                               @K or more
+         |  __K                               @K or more
+")
+
+  See @racket[match] for the semantics of each pattern.
+}
+
+@defform[(destruct* (val-expr ...) [(pat ...) body ...+] ...)]{
+  Similar to @racket[match*] but with the restrictions of @racket[destruct].
+
+  @examples[
+  #:eval the-eval
+  (define x (if b (list 1) (list 1 2)))
+  (define y (if b (list 10) (list 10 20)))
+  (destruct* (x y)
+    [((list p) (list q)) (+ p q)]
+    [((list p p*) (list q q*)) (+ p p* q q*)])]
+}
+
+@defform[(destruct-lambda [(pat ...) body ...+] ...)]{
+  Similar to @racket[match-lambda] but with the restrictions of @racket[destruct].
+
+  @examples[
+  #:eval the-eval
+  (map (destruct-lambda [(add x y) (+ x y)])
+       (list (if b (add 1 2) (add 3 4))
+             (add 5 6)
+             (if (not b) (add 7 8) (add 9 10))))]
+}
+
 @section{Value Browser Library}
 
 @defmodule[rosette/lib/value-browser]

rosette/guide/scribble/performance/performance-log.txt

@@ -1,4 +1,8 @@
 ;; This file was created by make-log-based-eval
+((require (only-in rosette/guide/scribble/util/lifted format-opaque))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
 ((current-bitwidth 5) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic x integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((solve (assert (> x 15)))
@@ -10,7 +14,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
 ((define (list-set lst idx val)
@@ -19,16 +23,7 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((list-set '(a b c) 1 'd) ((3) 0 () 0 () () (q values (a d c))) #"" #"")
-((define-symbolic* idx len integer?)
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((define lst (take '(a b c) len))
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
-((list-set lst idx 'd)
+((list-set '(a b c) 1 'd)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -37,7 +32,27 @@
   0
   ()
   ()
-  (c values c (0 (u . "{3340589848165897971:6}"))))
+  (c values c (0 (u . "'(a d c)\n"))))
+ #""
+ #"")
+((define-symbolic idx len integer?)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define lst (take '(a b c) len))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((format-opaque "~a" (list-set lst idx 'd))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(union #:size 6 #:hash -437123915298968900)\n"))))
  #""
  #"")
 ((define (list-set* lst idx val)
@@ -50,8 +65,7 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((list-set* '(a b c) 1 'd) ((3) 0 () 0 () () (q values (a d c))) #"" #"")
-((list-set* lst idx 'd)
+((list-set* '(a b c) 1 'd)
  ((3)
   1
   (((lib "rosette/guide/scribble/util/lifted.rkt")
@@ -60,17 +74,26 @@
   0
   ()
   ()
-  (c values c (0 (u . "{1844165362669051823:4}"))))
+  (c values c (0 (u . "'(a d c)\n"))))
+ #""
+ #"")
+((format-opaque "~a" (list-set* lst idx 'd))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(union #:size 4 #:hash -976833215883912073)\n"))))
  #""
  #"")
 ((define-values (width height) (values 5 5))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((define-symbolic* x y integer?)
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
+((define-symbolic x y integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define grid/2d (for/vector ((_ height)) (make-vector width #f)))
  ((3) 0 () 0 () () (c values c (void)))
  #""
@@ -91,10 +114,7 @@
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((define-symbolic* idx integer?)
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
+((define-symbolic idx integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((maybe-ref '(5 6 7) idx)
  ((3)
   1
@@ -110,7 +130,7 @@
    (0
     (u
      .
-     "(ite (&& (<= 0 idx$0) (<= idx$0 1)) (ite* (⊢ (= 0 idx$0) 5) (⊢ (= 1 idx$0) 6) (⊢ (= 2 idx$0) 7)) -1)"))))
+     "(ite\n (&& (<= 0 idx) (<= idx 1))\n (ite* (⊢ (= 0 idx) 5) (⊢ (= 1 idx) 6) (⊢ (= 2 idx) 7))\n -1)\n\n"))))
  #""
  #"")
 ((define (maybe-ref* lst idx)
@@ -127,7 +147,7 @@
   0
   ()
   ()
-  (c values c (0 (u . "(ite (= 0 idx$0) 5 (ite (= 1 idx$0) 6 -1))"))))
+  (c values c (0 (u . "(ite (= 0 idx) 5 (ite (= 1 idx) 6 -1))\n"))))
  #""
  #"")
 ((define-values (Add Sub Sqr Nop) (values (bv 0 2) (bv 1 2) (bv 2 2) (bv 3 2)))
@@ -190,15 +210,12 @@
   0
   ()
   ()
-  (c values c (0 (u . "(unsat)"))))
+  (c values c (0 (u . "(unsat)\n"))))
  #""
  #"")
-((clear-asserts!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((clear-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-((define-symbolic* idx integer?)
- ((3) 0 () 0 () () (c values c (void)))
- #""
- #"")
+((define-symbolic idx integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((list-set '(1 2 3) idx 4)
  ((3)
   1
@@ -211,15 +228,10 @@
   (c
    values
    c
-   (c
-    (0 (u . "(ite (= 0 idx$0) 4 1)"))
-    c
-    (0 (u . "(ite (= 0 idx$0) 2 (ite (= 0 (+ -1 idx$0)) 4 2))"))
-    c
    (0
     (u
      .
-      "(ite (= 0 idx$0) 3 (ite (= 0 (+ -1 idx$0)) 3 (ite (= 0 (+ -2 idx$0)) 4 3)))")))))
+     "(list\n (ite (= 0 idx) 4 1)\n (ite (= 0 idx) 2 (ite (= 0 (+ -1 idx)) 4 2))\n (ite (= 0 idx) 3 (ite (= 0 (+ -1 idx)) 3 (ite (= 0 (+ -2 idx)) 4 3))))\n\n"))))
  #""
  #"")
 ((define (list-set* lst idx val)
@@ -242,11 +254,9 @@
   (c
    values
    c
-   (c
-    (0 (u . "(ite (= 0 idx$0) 4 1)"))
-    c
-    (0 (u . "(ite (= 0 (+ -1 idx$0)) 4 2)"))
-    c
-    (0 (u . "(ite (= 0 (+ -2 idx$0)) 4 3)")))))
+   (0
+    (u
+     .
+     "(list\n (ite (= 0 idx) 4 1)\n (ite (= 0 (+ -1 idx)) 4 2)\n (ite (= 0 (+ -2 idx)) 4 3))\n\n"))))
  #""
  #"")

rosette/guide/scribble/performance/performance.scrbl

@@ -1,16 +1,13 @@
 #lang scribble/manual
 
 @(require scribble/core scribble/html-properties
-          scribble/bnf scribble/eval
+          scribble/bnf scribble/example
           (for-label (except-in racket list-set) errortrace
                      rosette/base/core/term
                      rosette/base/form/define
-                     rosette/query/form
-                     rosette/base/core/union
-                     (only-in rosette/query/finitize current-bitwidth)
-                     (only-in rosette/base/base bitvector)
-                     (only-in rosette/base/core/safe assert)
-                     (only-in rosette/base/core/forall for/all))
+                     rosette/query/query
+                     (only-in rosette/base/base bitvector assert for/all)
+                     (only-in rosette current-bitwidth))
           racket/runtime-path
           "../util/lifted.rkt"
           (only-in "../refs.scrbl" ~cite sympro:oopsla18))
@@ -21,15 +18,14 @@
 @(define-runtime-path profile.png "profile.png")
 @(define-runtime-path profile-xform.png "profile-xform.png")
 
+@(rosette-eval '(require (only-in rosette/guide/scribble/util/lifted format-opaque)))
+
 @title[#:tag "ch:performance"]{Performance}
 
-Rosette provides an efficient, general-purpose runtime for solver-aided programming.
-But as with any other form of programming, 
-scaling this runtime to challenging problems involves careful design,
-and sometimes requires changes to code to better suit Rosette's
-symbolic virtual machine (SVM) style of execution.
-This chapter describes common performance problems and solutions,
-as well as tools built into Rosette for diagnosing these problems.
+
+This chapter describes common performance problems in
+Rosette programs, how to solve them, and how to diagnose
+them with the built-in @tech{symbolic profiler}.
 
 @section[#:tag "sec:antipatterns"]{Common Performance Issues}
 
@@ -38,45 +34,51 @@ it is often due to one of four common issues, described next.
 
 @subsection{Integer and Real Theories}
 
-Rosette supports assertions containing symbolic values of integer or real type.
-But satisfiability solving with these types is expensive (or, in the worst case, undecidable),
-and even simple queries can be unacceptably slow.
+Rosette supports assertions and assumptions containing
+symbolic values of integer or real type. But solving queries
+with these types is expensive (or, in the worst case,
+undecidable), and even simple queries can be unacceptably
+slow.
 
-One solution to performance issues with assertions involving integers or reals
-is Rosette's @racket[current-bitwidth] parameter,
-which controls the @tech{reasoning precision} used for queries.
-When @racket[current-bitwidth] is set to a value @emph{k} other than @racket[#f],
-Rosette approximates @racket[integer?] and @racket[real?] values using signed @emph{k}-bit @racket[bitvector]s.
-This approximation can make assertions involving integers and reals
-more efficiently decidable.
+One solution is to change Rosette's
+@racket[current-bitwidth] parameter, which controls the
+@tech{reasoning precision} used for queries. When
+@racket[current-bitwidth] is set to a value @emph{k} other
+than @racket[#f], Rosette approximates @racket[integer?] and
+@racket[real?] values using signed @emph{k}-bit
+@racket[bitvector]s, which can make queries involving
+integers and reals faster to solve.
 
-But this approximation is unsound and may produce results that are 
-incorrect under the infinite-precision semantics of integers and reals
-(while being correct under the finite-precision semantics).
-For example, this program incorrectly says that no integer greater than 15 exists,
-because the setting of @racket[current-bitwidth] causes it to consider only values of @racket{x}
-that can be represented as a 5-bit bitvector.
+But this approximation is unsound and may produce results
+that are incorrect under the infinite-precision semantics of
+integers and reals (while being correct under the
+finite-precision semantics). For example, this program
+incorrectly says that no integer greater than 15 exists,
+because the setting of @racket[current-bitwidth] causes it
+to consider only values of @racket[x] that can be
+represented as a 5-bit bitvector.
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (current-bitwidth 5)
 (define-symbolic x integer?)
 (solve (assert (> x 15)))]
 
-So, choosing the right reasoning precision for an application involves navigating this tradeoff
-between performance and soundness. 
+So, choosing the right reasoning precision for an
+application involves navigating this tradeoff between
+performance and soundness.
 
 @subsection{Algorithmic Mismatch}
 
-Small algorithmic changes can have a large impact on the efficiency
-of the symbolic evaluation performed by the Rosette SVM.
-Often, the most efficient algorithm for symbolic inputs
-is different to the most efficient one for concrete inputs---an
-@deftech{algorithmic mismatch}.
+Small algorithmic changes can have a large impact on the
+efficiency of symbolic evaluation. Often, the most efficient
+algorithm for symbolic inputs is different to the most
+efficient one for concrete inputs---an @deftech{algorithmic
+ mismatch}.
 
-For example,
-consider this function to set the @tt{idx}th element of a list @tt{lst} to @tt{val}:
+For example, consider this function to set the @tt{idx}th
+element of a list @tt{lst} to @tt{val}:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define (list-set lst idx val)
   (let-values ([(front back) (split-at lst idx)])
     (append front (cons val (cdr back)))))
@@ -87,70 +89,76 @@ While appropriate for concrete inputs,
 this function exhibits poor performance when the
 inputs are symbolic:
 
-@interaction[#:eval rosette-eval
-(define-symbolic* idx len integer?)
+@examples[#:eval rosette-eval #:label #f
+(define-symbolic idx len integer?)
 (define lst (take '(a b c) len))
-(code:line (list-set lst idx 'd) (code:comment "symbolic union with 6 parts"))
+(eval:alts
+(code:line (list-set lst idx 'd) (code:comment "Symbolic union with 6 parts."))
+(format-opaque "~a" (list-set lst idx 'd)))
 ]
 
-The root cause is the @racket[split-at] operation,
-which separates the front and back of the list
-into different variables.
-Because the index @racket[idx] to split at is symbolic,
-the Rosette SVM creates two @tech{symbolic unions} to capture
-the possible front and back values
-as a function of @racket[idx].
-Even though the possible values of @racket[front] and @racket[back]
-are related, this separation loses the relationship.
+The root cause is the @racket[split-at] operation, which
+separates the front and back of the list into different
+variables. Because the index @racket[idx] to split at is
+symbolic, Rosette creates two @tech{symbolic unions} to
+capture the possible front and back values as a function of
+@racket[idx]. Even though the possible values of
+@racket[front] and @racket[back] are related, this
+separation loses the relationship.
 
-A better implementation for symbolic inputs
-avoids splitting the list by iterating over it,
-updating each position depending on whether its index is equal to @tt{idx}:
+A better implementation for symbolic inputs avoids splitting
+the list by iterating over it, updating each position
+depending on whether its index is equal to @tt{idx}:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define (list-set* lst idx val)
   (for/all ([lst lst])
     (map (lambda (i v) (if (= idx i) val v))
          (build-list (length lst) identity)
          lst)))
 (list-set* '(a b c) 1 'd)
-(code:line (list-set* lst idx 'd) (code:comment "smaller symbolic union with 4 parts"))
+(eval:alts
+(code:line (list-set* lst idx 'd) (code:comment "Smaller symbolic union with 4 parts."))
+(format-opaque "~a" (list-set* lst idx 'd)))
 ]
 
 @subsection{Irregular Representation}
 
 Just as the best algorithm for symbolic inputs can differ
-from that for concrete inputs (an @tech{algorithmic mismatch}),
-so can the best data structure.
-Programming with symbolic values is most efficient
-when data structures are regular;
-even though an @deftech{irregular representation} may be more space efficient for concrete data,
-it can have negative performance impacts when the data is symbolic.
+from that for concrete inputs (an @tech{algorithmic
+ mismatch}), so can the best data structure. Programming with
+symbolic values is most efficient when data structures are
+regular. Even though an @deftech{irregular representation}
+may be more space efficient for concrete data, it can have
+negative performance impacts when the data is symbolic.
 
-For example, consider representing a (mutable) 2D grid data structure
-using Rosette's lifted support for @tech[#:doc '(lib "scribblings/reference/reference.scrbl")]{vectors}.
-The obvious representation is to use nested vectors to represent the two dimensions:
+For example, consider representing a (mutable) 2D grid data
+structure using Rosette's lifted support for
+@tech[#:doc '(lib "scribblings/reference/reference.scrbl")]{vectors}.
+The obvious representation is to use nested
+vectors to represent the two dimensions:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define-values (width height) (values 5 5))
-(define-symbolic* x y integer?)
+(define-symbolic x y integer?)
 (define grid/2d
   (for/vector ([_ height])
     (make-vector width #f)))
 (vector-set! (vector-ref grid/2d y) x 'a)
 ]
 
-This representation is inefficient when indexed with symbolic values,
-because the dereferences are irregular:
-the dereference of the @racket[y]-coordinate returns a vector,
-whereas the dereference of the @racket[x]-coordinate returns a value.
-This irregularity requires Rosette to perform more symbolic evaluation work
-to faithfully track the usages of the nested vector.
+This representation is inefficient when indexed with
+symbolic values, because the dereferences are irregular: the
+dereference of the @racket[y]-coordinate returns a vector,
+whereas the dereference of the @racket[x]-coordinate returns
+a value. This irregularity requires Rosette to perform more
+symbolic evaluation work to faithfully track the usages of
+the nested vector.
 
 An alternative representation stores the entire grid in one vector,
 indexed using simple arithmetic:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define grid/flat
   (make-vector (* width height) #f))
 (vector-set! grid/flat (+ (* y width) x) 'a)
@@ -160,37 +168,38 @@ This variant improves performance by about 2×.
 
 @subsection{Missed Concretization}
 
-In addition to employing careful algorithmic and representational choices,
-fast solver-aided code provides as much information as possible
-about the feasible choices of symbolic values.
-Failure to make this information explicit
-results in @deftech{missed concretization} opportunities, and 
-these misses can cause significant performance degradation.
+In addition to employing careful algorithmic and
+representational choices, fast solver-aided code provides as
+much information as possible about the feasible choices of
+symbolic values. Failure to make this information explicit
+results in @deftech{missed concretization} opportunities,
+leading to performance degradation.
 
 For example, consider the following toy procedure,
 that returns the @racket[idx]th element of the list @racket[lst],
 but only if @racket[idx] is 0 or 1:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define (maybe-ref lst idx)
   (if (<= 0 idx 1)
       (list-ref lst idx)
       -1))
-(define-symbolic* idx integer?)
+(define-symbolic idx integer?)
 (maybe-ref '(5 6 7) idx)
 ]
 
-This procedure has poor performance when given a symbolic index @racket[idx],
-because the call to @racket[(list-ref lst idx)]
-passes a symbolic index,
-but the conditional establishes that the only possible values for that index are 0 or 1.
-When the Rosette SVM evaluates the first side of the conditional,
-it does not simplify the value of @racket[idx] to be only 0 or 1,
-and so the resulting encoding creates infeasible branches
-for cases where @racket[idx] is outside that range.
-An alternative version captures that concreteness:
+This procedure has poor performance when given a symbolic
+index @racket[idx], because the call to
+@racket[(list-ref lst idx)] passes a symbolic index, but the
+conditional establishes that the only possible values for
+that index are 0 or 1. When Rosette evaluates the
+first side of the conditional, it does not simplify the
+value of @racket[idx] to be only 0 or 1, and so the
+resulting encoding creates infeasible branches for cases
+where @racket[idx] is outside that range. An alternative
+version captures that concreteness:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (define (maybe-ref* lst idx)
   (cond [(= idx 0) (list-ref lst 0)]
         [(= idx 1) (list-ref lst 1)]
@@ -205,12 +214,13 @@ for the cases where @racket[idx] is greater than 1.
 
 Rosette includes a @deftech[#:key "symbolic profiler"]{symbolic profiler}
 for diagnosing performance issues in solver-aided programs.
-The symbolic profiler instruments key metrics in the Rosette SVM
-and relates them to the performance of a Rosette program,
-suggesting the locations of potential bottlenecks---that is, parts of
-the program that are difficult to evaluate symbolically.
-More details about symbolic profiling are available
-in the related technical paper @~cite[sympro:oopsla18].
+The symbolic profiler instruments key metrics in Rosette's
+symbolic evaluator and relates them to the performance of a
+Rosette program, suggesting the locations of potential
+bottlenecks---i.e., parts of the program that are
+difficult to evaluate symbolically. More details about
+symbolic profiling are available in the related technical
+paper @~cite[sympro:oopsla18].
 
 To run the symbolic profiler on a program file @nonterm{prog},
 use the @exec{raco} command:
@@ -221,7 +231,7 @@ After executing @nonterm{prog},
 the symbolic profiler produces a browser-based output summarizing the results,
 similar to this output:
 
-@(image profile.png #:scale 0.7)
+@(image profile.png #:scale 0.425)
 
 The top half of this output visualizes the evolution of the Racket call stack
 over time.
@@ -230,16 +240,17 @@ with its width corresponding to the total time taken by the call.
 Blue highlighted regions reflect @tech{solver} activity
 generated by Rosette @seclink["sec:queries"]{queries}.
 
-The bottom half summarizes important metrics about the SVM on a per-procedure basis.
-Each procedure invoked by the program has a row in the table,
-with columns that measure:
+The bottom half summarizes important metrics about the
+symbolic evaluation on a per-procedure basis. Each procedure
+invoked by the program has a row in the table, with columns
+that measure:
 
 @itemlist[
  @item{The total @bold{time} taken by all invocations of the procedure.}
- @item{The @bold{term count}, the total number of @tech[#:key "symbolic term"]{symbolic terms} created by the procedure.}
+ @item{The @bold{term count}, which is the total number of @tech[#:key "symbolic term"]{symbolic terms} created by the procedure.}
  @item{The number of @bold{unused terms}, which are terms created but never sent to a solver.}
- @item{The @bold{union size}, counting the total size of all @tech[#:key "symbolic unions"]{symbolic unions} created by the procedure.}
- @item{The @bold{merge count}, summing the number of execution paths merged by the SVM within the procedure.}
+ @item{The @bold{union size}, which is the total size of all @tech[#:key "symbolic unions"]{symbolic unions} created by the procedure.}
+ @item{The @bold{merge cases}, which is the total number of execution paths merged by Rosette within the procedure.}
  ]
 
 Procedures are ranked by a @bold{score}, which summarizes the other data in the table.
@@ -286,15 +297,14 @@ The @exec{raco symprofile @nonterm{prog}} command accepts the following command-
 
 @section{Walkthrough: Debugging Rosette Performance}
 
-To illustrate a typical Rosette performance debugging process,
-consider building a small solver-aided program
-for verifying optimizations in a toy calculator language.
-First, we define the calculator language,
-in which programs are lists of operations,
-and specify its semantics
-with a simple recursive interpreter:
+To illustrate a typical Rosette performance debugging
+process, consider building a small solver-aided program for
+verifying optimizations in a toy calculator language. First,
+we define the calculator language, in which programs are
+lists of operations, and specify its semantics with a simple
+recursive interpreter:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (code:comment "Calculator opcodes.")
 (define-values (Add Sub Sqr Nop)
   (values (bv 0 2) (bv 1 2) (bv 2 2) (bv 3 2)))
@@ -317,12 +327,12 @@ with a simple recursive interpreter:
         [(eq? op Sqr) (bvmul acc acc)]
         [else         acc]))]))]
 
-One potential optimization for programs in this language
-is to replace subtractions with additions.
-The @tt{sub->add} procedure performs this operation
-at a given index in a program:
+One potential optimization for programs in this language is
+to replace subtractions with additions. The @tt{sub->add}
+procedure performs this operation at a given index in a
+program:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (code:comment "Functionally sets lst[idx] to val.")
 (define (list-set lst idx val) ; Functionally sets
   (match lst                   ; lst[idx] to val.
@@ -339,14 +349,13 @@ at a given index in a program:
       (list-set prog idx (list Add (bvneg (cadr ins))))
       prog))]
 
-To check that this optimization is correct,
-we implement a tiny verification tool @tt{verify-xform}
-that constructs a symbolic calculator program of size @tt{N},
-applies the optimization,
-and checks that the original and optimized programs
-produce the same outputs:
+To check that this optimization is correct, we implement a
+tiny verification tool @tt{verify-xform} that constructs a
+symbolic calculator program of size @tt{N}, applies the
+optimization, and checks that the original and optimized
+programs produce the same outputs:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (code:comment "Verifies the given transform for all programs of length N.")
 (define (verify-xform xform N) ; Verifies the given
   (define P                    ; transform for all 
@@ -363,51 +372,50 @@ produce the same outputs:
 
 We can verify @tt{sub->add} for all calculator programs of size 5:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (verify-xform sub->add 5)
 ]
 
-which produces no counterexamples, as expected.
+This produces no counterexamples, as expected.
 
-@(rosette-eval '(clear-asserts!))
+@(rosette-eval '(clear-vc!))
 @(rosette-eval '(clear-terms!))
 @subsection{Performance Bottlenecks}
 
-Verifying @tt{sub->add} for larger values of @tt{N}
-causes the performance of @tt{verify-xform} to degrade,
-from less than a second when @tt{N} = 5 to
-a dozen seconds when @tt{N} = 20.
-To identify the source of this performance issue,
-we can invoke the @tech{symbolic profiler} on the verifier,
-producing the output below (after selecting the "Collapse solver time" checkbox):
+Verifying @tt{sub->add} for larger values of @tt{N} causes
+the performance of @tt{verify-xform} to degrade, from a
+couple of seconds when @tt{N} = 5 to over a minute when @tt{N}
+= 20. To identify the source of this performance issue, we
+can invoke the @tech{symbolic profiler} on the verifier,
+producing the output below (after selecting the ``Collapse
+solver time'' checkbox):
 
-@(image profile-xform.png #:scale 0.7)
+@(image profile-xform.png #:scale 0.425)
 
-The symbolic profiler identifies @tt{list-set} as the bottleneck in this program.
-The output shows that @tt{list-set} creates many symbolic terms,
-and performs many symbolic operations (the "Union Size" and "Merge Count" columns).
+The symbolic profiler identifies @tt{list-set} as the
+bottleneck in this program. The output shows that @tt{list-set}
+creates many symbolic terms, and performs many symbolic
+operations (the ``Union Size'' and ``Merge Cases'' columns).
 
-The core issue here is an @tech{algorithmic mismatch}:
-@tt{list-set} makes a recursive call guarded by a short-circuiting condition
-@racket[(= idx 0)] that is symbolic when @racket[idx] is unknown.
-When a condition's truth value is unknown,
-the Rosette SVM must execute both branches of the conditional,
-and then merge the two resulting values together
-under @tech{path conditions} that summarize the branching decisions
-required to reach each value.
-In this example, this @emph{symbolic execution}
-therefore always executes the recursive call,
-and each call creates a larger path condition,
-since it must summarize all the previous recursive calls.
-This behavior leads to a quadratic growth in the symbolic representation of the list
-returned by @tt{list-set}:
-@interaction[#:eval rosette-eval
-(define-symbolic* idx integer?)
+The core issue here is an @tech{algorithmic mismatch}: @tt{list-set}
+makes a recursive call guarded by a short-circuiting
+condition @racket[(= idx 0)] that is symbolic when
+@racket[idx] is unknown. When a condition's truth value is
+unknown, Rosette must execute both branches of the
+conditional, and then merge the resulting symbolic values.
+So, in our example, Rosette always executes the recursive
+call, and each call creates a larger symbolic value that
+encodes the results of all the previous recursive calls.
+This behavior leads to a quadratic growth in the symbolic
+representation of the list returned by @tt{list-set}:
+
+@examples[#:eval rosette-eval #:label #f 
+(define-symbolic idx integer?)
 (list-set '(1 2 3) idx 4)]
 
 The solution is to alter @tt{list-set} to recurse unconditionally:
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f #:no-prompt
 (define (list-set* lst idx val)
   (match lst
     [(cons x xs)
@@ -415,12 +423,12 @@ The solution is to alter @tt{list-set} to recurse unconditionally:
            (list-set* xs (- idx 1) val))]
     [_ lst]))]
 
-In this revision, the SVM still evaluates both branches
+In this revision, Rosette still evaluates both branches
 of the conditional, but neither side of the conditional recurses,
-and so the path conditions no longer grow quadratically.
+and so the verification conditions no longer grow quadratically.
 
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval #:label #f
 (list-set* '(1 2 3) idx 4)]
 
 The performance of @tt{verify-xform} after this change
-improves by 2× for @tt{N} = 20.
+improves by 3× for @tt{N} = 20.

rosette/guide/scribble/performance/xform.rkt

@@ -0,0 +1,62 @@
+#lang rosette
+
+
+(define-values (Add Sub Sqr Nop)
+  (values (bv 0 2) (bv 1 2) (bv 2 2) (bv 3 2)))
+
+(define (calculate prog [acc (bv 0 4)])
+  (cond                      ; An interpreter for 
+    [(null? prog) acc]       ; calculator programs.
+    [else                    ; A program is list of 
+     (define ins (car prog)) ; '(op) or '(op arg)
+     (define op (car ins))   ; instructions that up-
+     (calculate              ; date acc, where op is 
+      (cdr prog)             ; a 2-bit opcode and arg
+      (cond                  ; is a 4-bit constant.
+        [(eq? op Add) (bvadd acc (cadr ins))]
+        [(eq? op Sub) (bvsub acc (cadr ins))]
+        [(eq? op Sqr) (bvmul acc acc)]
+        [else         acc]))]))
+
+(define (list-set lst idx val) ; Functionally sets
+  (match lst                   ; lst[idx] to val.
+    [(cons x xs)
+     (if (= idx 0) 
+         (cons val xs)
+         (cons x (list-set xs (- idx 1) val)))]
+    [_ lst]))
+
+(define (list-set* lst idx val)
+  (match lst
+    [(cons x xs)
+     (cons (if (= idx 0) val x)
+           (list-set* xs (- idx 1) val))]
+    [_ lst]))
+
+(define (sub->add prog idx list-set)        
+  (define ins (list-ref prog idx))  
+  (if (eq? (car ins) Sub)          
+      (list-set prog idx (list Add (bvneg (cadr ins))))
+      prog))
+
+(define (verify-xform xform N list-set)  
+  (define P                     
+    (for/list ([i N])          
+      (define-symbolic* op (bitvector 2))   
+      (define-symbolic* arg (bitvector 4))
+      (if (eq? op Sqr) (list op) (list op arg))))
+  (define-symbolic* acc (bitvector 4))
+  (define-symbolic* idx integer?)
+  (define xP (xform P idx list-set))
+  (verify  
+   (assert (eq? (calculate P acc) (calculate xP acc)))))
+
+(module+ slow
+  (clear-terms!)
+  (clear-vc!)
+  (time (verify-xform sub->add 20 list-set)))
+
+(module+ fast
+  (clear-terms!)
+  (clear-vc!)
+  (time (verify-xform sub->add 20 list-set*)))

rosette/guide/scribble/reflection/state-log.txt

@@ -0,0 +1,436 @@
+;; This file was created by make-log-based-eval
+((require (only-in rosette/guide/scribble/util/lifted opaque))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define-symbolic a b c d boolean?)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list a c d b)\n"))))
+ #""
+ #"")
+((assume a) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a #t)\n"))))
+ #""
+ #"")
+((if b
+   (begin
+     (printf "Then branch:\n ~a\n" (vc))
+     (assert c)
+     (printf " ~a\n" (vc))
+     1)
+   (begin
+     (printf "Else branch:\n ~a\n" (vc))
+     (assert d)
+     (printf " ~a\n" (vc))
+     2))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(ite b 1 2)\n"))))
+ #"Then branch:\n #(struct:vc (&& a b) #t)\n #(struct:vc (&& a b) (|| c (! (&& a b))))\nElse branch:\n #(struct:vc (&& a (! b)) #t)\n #(struct:vc (&& a (! b)) (|| d (! (&& a (! b)))))\n"
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(vc a (&& (|| (! b) (|| c (! (&& a b)))) (|| b (|| d (! (&& a (! b)))))))\n"))))
+ #""
+ #"")
+((append (take (terms) 5) (list (opaque "...")))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(list\n a\n c\n d\n b\n (&& (|| (! b) (|| c (! (&& a b)))) (|| b (|| d (! (&& a (! b))))))\n ...)\n\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+(vc-true
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((vc? vc-true) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((vc-assumes vc-true) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((vc-asserts vc-true) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((vc-true? vc-true) ((3) 0 () 0 () () (q values #t)) #"" #"")
+((vc-true? 1) ((3) 0 () 0 () () (q values #f)) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((assume a) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a #t)\n"))))
+ #""
+ #"")
+((assert b) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a (|| b (! a)))\n"))))
+ #""
+ #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc #t #t)\n"))))
+ #""
+ #"")
+((define-symbolic a b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((assume a) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a #t)\n"))))
+ #""
+ #"")
+((with-vc (begin (when b (error 'b "No b allowed!")) 1))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(normal 1 (vc a (|| (! b) (! (&& a b)))))\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a #t)\n"))))
+ #""
+ #"")
+((with-vc vc-true (if b (assume #f) (assert #f)))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c
+   values
+   c
+   (0
+    (u
+     .
+     "(failed\n (exn:fail:svm:merge \"[merge] failed\" #<continuation-mark-set>)\n (vc (! b) b))\n\n"))))
+ #""
+ #"")
+((vc)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(vc a #t)\n"))))
+ #""
+ #"")
+((clear-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((clear-vc!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'()\n"))))
+ #""
+ #"")
+((define (get-a) (define-symbolic a integer?) a)
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define a0 (get-a)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((+ a0 3)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(+ 3 a)\n"))))
+ #""
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list a (+ 3 a))\n"))))
+ #""
+ #"")
+((define (query-a a) (verify (assert (= a (get-a)))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((query-a a0)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(unsat)\n"))))
+ #""
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list a (+ 3 a))\n"))))
+ #""
+ #"")
+((clear-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'()\n"))))
+ #""
+ #"")
+((query-a a0)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [a 1]\n [a 0])\n"))))
+ #""
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list a (! (= a a)) (= a a))\n"))))
+ #""
+ #"")
+((clear-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((require (only-in racket collect-garbage))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((define (unused-terms! n)
+   (define-symbolic* a integer?)
+   (let loop ((n n)) (if (<= n 1) a (+ a (loop (- n 1)))))
+   (void))
+ ((3) 0 () 0 () () (c values c (void)))
+ #""
+ #"")
+((length (terms)) ((3) 0 () 0 () () (q values 0)) #"" #"")
+((time (unused-terms! 50000))
+ ((3) 0 () 0 () () (c values c (void)))
+ #"cpu time: 357 real time: 365 gc time: 17\n"
+ #"")
+((length (terms)) ((3) 0 () 0 () () (q values 50000)) #"" #"")
+((collect-garbage) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((length (terms)) ((3) 0 () 0 () () (q values 50000)) #"" #"")
+((clear-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((collect-garbage) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((gc-terms!) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((length (terms)) ((3) 0 () 0 () () (q values 0)) #"" #"")
+((time (unused-terms! 50000))
+ ((3) 0 () 0 () () (c values c (void)))
+ #"cpu time: 410 real time: 416 gc time: 40\n"
+ #"")
+(50000 ((3) 0 () 0 () () (q values 50000)) #"" #"")
+((collect-garbage) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((length (terms)) ((3) 0 () 0 () () (q values 0)) #"" #"")
+((define-symbolic a b integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list b a)\n"))))
+ #""
+ #"")
+((with-terms (begin0 (verify (assert (= (+ a b) 0))) (println (terms))))
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(model\n [a 1]\n [b 0])\n"))))
+ #"(list (+ a b) b a (! (= 0 (+ a b))) (= 0 (+ a b)))\n"
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list b a)\n"))))
+ #""
+ #"")
+((with-terms
+  (list)
+  (begin (println (terms)) (define-symbolic c integer?) (println (terms))))
+ ((3) 0 () 0 () () (c values c (void)))
+ #"'()\n(list c)\n"
+ #"")
+((terms)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "(list b a)\n"))))
+ #""
+ #"")

rosette/guide/scribble/reflection/state-reflection.scrbl

@@ -2,130 +2,351 @@
 
 @(require (for-label 
            rosette/query/query rosette/base/form/define
-           rosette/base/core/term 
-           (only-in rosette/base/core/bool pc asserts clear-asserts! with-asserts with-asserts-only)
-           (only-in rosette/base/core/safe assert) 
+           (only-in rosette/base/base
+                    assert assume term?
+                    vc vc? vc-assumes vc-asserts
+                    clear-vc! with-vc vc-true vc-true?
+                    result? result-value result-state
+                    normal normal? failed failed?
+                    terms with-terms clear-terms! gc-terms!)
            racket)
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+          scribble/core scribble/html-properties scribble/example racket/sandbox
+          racket/runtime-path 
           "../util/lifted.rkt")
-@(require (only-in "../refs.scrbl" ~cite rosette:pldi14))
 
-@(define rosette-eval (rosette-evaluator))
+
+@(define-runtime-path root ".")
+@(define rosette-eval (rosette-log-evaluator (logfile root "state-log")))
 
 @title[#:tag "sec:state-reflection"]{Reflecting on Symbolic State}
 
-Like standard program execution, Rosette's symbolic evaluation @~cite[rosette:pldi14] can be
-understood as a sequence of transitions from one @deftech{program state} to the next. In
-addition to the memory and register values, the state of a Rosette program also includes
-the current @deftech{path condition} and the current @deftech{assertion store}. The path
-condition is a boolean value encoding the branch decisions taken to reach the present state,
-and the assertion store is the set of boolean values (i.e., constraints) that have been asserted
-so far. This section describes the built-in facilities for accessing and modifying various
-aspects of the symbolic state from within a Rosette program.  In general, these facilities should
-only be used by expert Rosette programmers to implement low-level solver-aided tools.  
 
-@declare-exporting[rosette/base/base #:use-sources (rosette/base/core/bool rosette/base/core/term)]
+Like standard program execution, Rosette's @tech{symbolic
+ evaluation} can be viewed as a function that operates on
+@deftech[#:key "program state"]{program states}. The state
+of a Rosette program includes its Racket state (memory,
+environment, and so on) and its symbolic state. The key
+parts of the symbolic state are the current @deftech{verification condition}
+(VC) and the current @deftech{symbolic heap}.
+The heap consists of all the @tech[#:key "symbolic term"]{symbolic terms}
+created so far. The verification condition tracks all the
+@racketlink[assume]{assumptions} and @racketlink[assert]{assertions}
+issued on @emph{any} path between the starting program state
+and the current state. Unlike concrete execution, which
+evaluates just one path through a program, Rosette evaluates
+all possible paths when the decision on which path to take
+depends on a symbolic value. The symbolic heap and the
+verification condition reflect the current state of this
+all-path evaluation.
+
+@(rosette-eval '(require (only-in rosette/guide/scribble/util/lifted opaque)))
+@examples[#:eval rosette-eval #:label #f #:no-prompt
+(define-symbolic a b c d boolean?)
+(code:line (terms) (code:comment "Symbolic heap."))
+(assume a)
+(code:line (vc)    (code:comment "Verification condition."))
+(if b
+    (begin
+      (printf "Then branch:\n ~a\n" (vc))
+      (assert c)
+      (printf " ~a\n" (vc))
+      1)
+    (begin
+      (printf "Else branch:\n ~a\n" (vc))
+      (assert d)
+      (printf " ~a\n" (vc))
+      2))
+(vc)
+(eval:alts
+ (terms)
+ (append (take (terms) 5) (list (opaque "..."))))]
+
+This section describes the built-in facilities for accessing
+and modifying various aspects of the symbolic state from
+within a Rosette program. These facilites are useful for
+low-level debugging and optimizations of Rosette-based
+tools. But they also make it possible to 
+violate the state invariants maintained by Rosette, so it is
+best to use them sparingly.
+
+@declare-exporting[rosette/base/base
+                   #:use-sources
+                   (rosette/base/base)]
+
+@(rosette-eval '(clear-vc!))
+@section[#:tag "sec:vc"]{Verification Conditions}
+
+@deftogether[(@defproc[(vc? [v any/c]) boolean?]
+              @defproc[(vc-assumes [v vc?]) boolean?]
+              @defproc[(vc-asserts [v vc?]) boolean?])]{
+                                                   
+ A verification condition (VC) is a structure of type
+ @racket[vc?]. It consists of two (concrete or symbolic)
+ boolean values that reflect the assumptions and assertions
+ issued during symbolic evaluation. Programs can access these
+ values using @racket[vc-assumes] and @racket[vc-asserts]. }
+
+@deftogether[(@defthing[vc-true vc?]
+              @defproc[(vc-true? [v any/c]) boolean?])]{
+                                                        
+ The true verification condition, @racket[vc-true], is a
+ value of type @racket[vc?] that consists of a true 
+ assumption and assertion. The true verification condition
+ is recognized by @racket[vc-true?].
+ 
+ @examples[#:eval rosette-eval
+ vc-true
+ (vc? vc-true)
+ (vc-assumes vc-true)
+ (vc-asserts vc-true)
+ (vc-true? vc-true)
+ (vc-true? 1)]        
  
-@defproc[(pc) boolean?]{
-Returns the current path condition. 
-@examples[#:eval rosette-eval
-(define-symbolic a b boolean?)
-(if a
-    (if b
-        #f
-        (pc))
-    #f)]
 }
 
-@defproc[(asserts) (listof boolean?)]{
-Returns the contents of the @tech["assertion store"] as a list of symbolic
-boolean values (or @racket[#f]) that have been asserted so far. 
+                                                   
+@defproc[(vc) vc?]{
+                                                   
+ The current @tech{verification condition}, @racket[(vc)],
+ is a value of type @racket[vc?]. At the start of evaluation,
+ @racket[(vc)] has the value @racket[vc-true]. As the
+ evaluation progresses along all paths, the current
+ @racket[(vc)] accumulates all the assertions and assumptions
+ issued on these paths.
+
+ The current @racket[(vc)] state can be cleared using
+ @racket[clear-vc!]. This resets @racket[(vc)] to its
+ starting value, @racket[vc-true]. 
+
+
 @examples[#:eval rosette-eval
+(vc)
 (define-symbolic a b boolean?)
-(assert a)
-(asserts)
+(vc)
+(assume a)
+(vc)
 (assert b)
-(asserts)]
+(vc)
+(clear-vc!)
+(vc)]
 }
-@(rosette-eval '(clear-asserts!))
 
-@defproc[(clear-asserts!) void?]{
- Clears the @tech["assertion store"] from all symbolic
- boolean values (or @racket[#f]) that have been asserted so far.
- Rosette programs @emph{should not clear} the assertion
- store unless they are implementing low-level tools.
+@defproc[(clear-vc!) void?]{
+Clears the current verification condition by setting it to @racket[vc-true].
+See @racket[vc] for details.               
+}
+
+@defform*[((with-vc expr)
+           (with-vc vc-expr expr))
+          #:contracts ([vc-expr vc?])]{
+
+ Evaluates @racket[expr] with @racket[(vc)] set to
+ @racket[vc-expr], returns the result, and restores
+ @racket[(vc)] to its old value. If @racket[vc-expr] is not
+ given, it defaults to @racket[(vc)], so
+ @racket[(with-vc expr)] is equivalent to
+ @racket[(with-vc (vc) expr)].
+
+ The result of a @racket[with-vc] expression is a value of
+ type @racket[result?]. If @racket[expr] terminates normally,
+ then the result is @racket[normal?], and its
+ @racket[result-value] contains the value computed by
+ @racket[expr]. If @racket[expr] fails, the result is
+ @racket[failed?], and its @racket[result-value] contains an
+ @racket[exn:fail?] exception that represents the cause of
+ the abnormal termination. In either case,
+ @racket[result-state] holds the final verification condition
+ generated during the evaluation of @racket[expr], starting
+ with @racket[vc-expr], or @racket[(vc)], as the initial
+ verification condition.
+
+ In the context of symbolic evaluation, @racket[expr]
+ terminates normally if it has at least one path of execution
+ that terminates normally. A path terminates normally if it
+ is free of any assumption or assertion violations---i.e., any 
+ @racket[(assume #, @var{e})] or @racket[(assert #, @var{e})]
+ expressions where @var{e} evaluates to @racket[#f]. Failures
+ due to exceptions are treated as assertion violations.
+
  @examples[#:eval rosette-eval
  (define-symbolic a b boolean?)
- (assert a)
- (assert b)
- (asserts)
- (clear-asserts!)
- (asserts)]
+ (assume a)
+ (vc)
+ (code:comment "Normal termination, starting with (vc).")
+ (code:comment "The error along the path where b is true")
+ (code:comment "is treated as an assertion violation.")
+ (with-vc
+   (begin
+     (when b      
+       (error 'b "No b allowed!"))
+     1))
+ (code:line (vc) (code:comment "(vc) is unchanged."))
+ (code:comment "Abnormal termination, starting with vc-true.")
+ (with-vc vc-true
+   (if b
+       (assume #f)
+       (assert #f)))
+ (code:line (vc) (code:comment "(vc) is unchanged."))]
 }
 
-@(rosette-eval '(clear-asserts!))
-@defform[(with-asserts expr)]{
-Returns two values: the result of evaluating @racket[expr] and the assertions 
-generated during the evaluation of @racket[expr]. These  
-assertions will not appear in the assertion store after 
-@racket[with-asserts] returns.
+@deftogether[(@defproc[(result? [v any/c]) boolean?]
+              @defproc[(result-value [v result?]) any/c]
+              @defproc[(result-state [v result?]) any/c] 
+              @defproc[(normal?  [v any/c]) boolean?]
+              @defproc[(failed? [v any/c]) boolean?])]{
+
+ A @racket[result?] value represents the result of symbolic
+ evaluation, which includes an output value,
+ @racket[(result-value v)], and a part of the output state,
+ @racket[(result-state v)]. Every result is either
+ @racket[normal?], if the evaluation terminated normally, or
+ @racket[failed?] otherwise.
+
+ See also @racket[with-vc].
  
-@examples[#:eval rosette-eval
-(define-symbolic a b boolean?)  
-(define-values (result asserted) 
-  (with-asserts 
-   (begin (assert a) 
-          (assert b) 
-          4)))
-(printf "result = ~a\n" result)
-(printf "asserted = ~a\n" asserted)
-(asserts)
-]
 }
 
-@defform[(with-asserts-only expr)]{
-Like @racket[with-asserts], but returns only the assertions generated
-during the evaluation of @racket[expr].
-@examples[#:eval rosette-eval
-(define-symbolic a b boolean?)  
-(with-asserts-only 
-   (begin (assert a) 
-          (assert b) 
-          4))
-]
-}
+@section[#:tag "sec:heap"]{Symbolic Heap}
+
 
 @(rosette-eval '(clear-terms!))
-@defparam[term-cache h hash?]{
-A parameter that holds the cache of all @seclink["sec:symbolic-terms"]{symbolic terms}
-constructed during symbolic evaluation. This cache stores terms for the purposes of
-partial cannonicalization.  In particular, Rosette uses the term cache to ensure that no
-syntactically identical terms are created. Rosette programs  
-@emph{should not modify} the term cache unless they are implementing low-level tools.
-@examples[#:eval rosette-eval
-(pretty-print (term-cache))         
-(define-symbolic a b c d integer?)
-(pretty-print (term-cache))
-(* d (- (+ a b) c))
-(pretty-print (term-cache))]
-}                              
+@(rosette-eval '(clear-vc!))
+
+
+@defproc[(terms) (listof term?)]{
+                              
+ Returns a list of all @seclink["sec:symbolic-terms"]{symbolic terms}
+ generated during symbolic evaluation. These
+ terms form the contents of the current @tech{symbolic heap}.
+ Rosette uses the symbolic heap to ensure that no
+ syntactically identical terms are created. 
+
+ The symbolic heap is not garbage collected, which means
+ that long running applications may experience memory
+ pressure. There are two ways to solve this issue, depending
+ on the application's behavior.
+
+ If the application is performing many independent queries
+ that do @emph{not} share @emph{any} symbolic constants, then
+ the application may safely clear the heap between
+ query invocations using @racket[clear-terms!]. This is the
+ most common scenario.
+  
+ If the application is solving a series of related queries,
+ using @racket[clear-terms!] can lead to incorrect behavior.
+ In this scenario, the safe solution is to use a
+ garbage-collected heap by invoking @racket[(gc-terms!)].
+ This has the effect of changing the internal representation
+ of the heap to use a more expensive data structure that
+ cooperates with Racket's garbage collector. Because of the
+ added runtime overhead, this setting is best saved for when
+ the default heap consumes too much memory.
 
-@(rosette-eval '(clear-terms!))
-@defproc[(clear-terms! [terms (or/c #f (listof term?)) #f]) void?]{
-Clears the entire term-cache if invoked with @racket[#f] (default), or 
-it evicts all of the given @racket[terms] as well as any expressions that transitively
-contain them. Rosette programs @emph{should not clear} the term cache unless they are
-implementing low-level tools.
 @examples[#:eval rosette-eval
-(term-cache)                 
-(define-symbolic a b c d integer?)
-(pretty-print (term-cache))
-(* d (- (+ a b) c))
-(pretty-print (term-cache))
-(clear-terms! (list c d))
-(pretty-print (term-cache))
+(terms)
+(define (get-a)
+  (define-symbolic a integer?)
+  a)
+(define a0 (get-a))
+(+ a0 3)
+(terms)
+(code:comment "In the following scenario, using clear-terms! leads to")
+(code:comment "incorrect behavior: (query-a a0) should always return")
+(code:comment "unsat? according to the semantics of define-symbolic.")
+(code:comment "But if the heap is cleared, it returns sat? because a0")
+(code:comment "is bound to a constant that no longer exists in the heap.")
+(define (query-a a)
+  (verify
+   (assert (= a (get-a)))))
+(query-a a0)
+(terms)
 (clear-terms!)
-(pretty-print (term-cache))]
+(terms)
+(code:line (query-a a0) (code:comment "Wrong result."))
+(terms)]
+}                              
+
+
+@defproc[(clear-terms! [ts (or/c #f (listof term?)) #f]) void?]{
+
+ Clears the symbolic heap of all terms if @racket[ts] is
+ false; otherwise, clears all the terms in @racket[ts] and
+ any expressions that transitively contain them. Clearing the
+ heap is @emph{not} safe in general; see @racket[terms] for
+ details and examples. }
+
+@(rosette-eval '(clear-terms!))
+@(rosette-eval '(require (only-in racket collect-garbage)))
+@defproc[(gc-terms!) void?]{
+
+ Changes the internal representation of the symbolic heap to
+ a data structure that cooperates with Racket's garbage
+ collector. The resulting heap is initialized with the
+ reachable terms from the current symbolic heap, as given by
+ @racket[(terms)]. This setting ensures that unused terms are
+ garbage-collected throughout symbolic evaluation.
+ 
+ @examples[#:eval rosette-eval
+ (code:comment "Creates n unreachable terms of the form (+ a (+ a ...)).")
+ (define (unused-terms! n)
+  (define-symbolic* a integer?)
+  (let loop ([n n])
+    (if (<= n 1)
+        a
+        (+ a (loop (- n 1)))))
+  (void))
+ (code:line (length (terms))   (code:comment "Empty heap."))
+ (time (unused-terms! 50000))
+ (length (terms))
+ (collect-garbage)
+ (code:line (length (terms))   (code:comment "GC has no effect on the default heap."))
+ (clear-terms!)
+ (collect-garbage)
+ (code:line (gc-terms!)        (code:comment "Use gc-terms! to change the representation."))
+ (length (terms))
+ (time (unused-terms! 50000))
+ (eval:alts (length (terms)) 50000)
+ (collect-garbage)
+ (code:line (length (terms))   (code:comment "The heap now cooperates with GC."))
+]
+                                  
+}
+
+
+@defform*[((with-terms expr)
+           (with-terms terms-expr expr))
+          #:contracts ([terms-expr (listof term?)])]{
+
+ Evaluates @racket[expr] with @racket[(terms)] set to
+ @racket[terms-expr], returns the result, and restores
+ @racket[(terms)] to the value it held before the evaluation
+ of @racket[expr]. If @racket[terms-expr] is not given, it
+ defaults to @racket[(terms)], so @racket[(with-terms expr)]
+ is equivalent to @racket[(with-terms (terms) expr)].
+
+ The result of a @racket[with-terms] expression is the output 
+ of @racket[expr].
+ 
+ Note that none of the terms created during the evaluation
+ of @racket[expr] are preserved in the heap, and having those
+ terms escape the dynamic extent of @racket[expr] is usually
+ a sign of a programming error. It can lead to incorrect
+ behavior, similarly to using @racket[clear-terms!].
+
+ @examples[#:eval rosette-eval
+ (define-symbolic a b integer?)
+ (terms)
+ (with-terms
+   (begin0
+     (verify (assert (= (+ a b) 0)))
+     (println (terms))))
+ (terms)
+ (with-terms (list) ; Empty heap
+   (begin
+     (println (terms))
+     (define-symbolic c integer?)
+     (println (terms))))
+ (terms)]
 }
 
 @(kill-evaluator rosette-eval)

rosette/guide/scribble/reflection/symbolic-reflection.scrbl

@@ -5,7 +5,7 @@
 
 @title[#:tag "ch:symbolic-reflection" #:style 'toc]{Symbolic Reflection}
 
-This chapter describes @deftech{symbolic reflection}, a convenient 
+This chapter describes @deftech{symbolic reflection}, a  
 mechanism for manipulating the representation of symbolic values 
 (Section @seclink["sec:value-reflection"]{7.1}) and 
 the state of the symbolic evaluation from within a Rosette program 

rosette/guide/scribble/reflection/test.rkt

@@ -1,23 +0,0 @@
-#lang rosette
-
-(define-symbolic b boolean?)
-(define v (vector 1))
-(define w (vector 2 3))
-(define s (if b v w))
-s
-(type-of s)
-(eq? s v)
-(eq? s w)
-(define u (if b '(1 2) 3))
-u
-(type-of u)
-
-(define (test)
-  (define-symbolic c boolean?)
-  (define v (if c #t 0))
-  (define u (if b (vector v) 4))
-  (list v u))
-
-(test)
-
-(union-contents u)

rosette/guide/scribble/reflection/value-reflection.scrbl

@@ -2,15 +2,12 @@
 
 @(require (for-label 
            rosette/solver/solver rosette/solver/solution rosette/query/query
-           rosette/base/form/define rosette/query/eval (only-in rosette/base/base bitvector ~>)
+           rosette/base/form/define  
            rosette/base/core/term rosette/base/core/type rosette/base/core/union
-           (only-in rosette/base/core/bool asserts)
-           (only-in rosette/base/core/reflect symbolics)
-           rosette/base/core/forall rosette/lib/lift ;rosette/lib/match 
-           (only-in rosette/base/core/safe assert) 
-           racket)
-           ;(except-in racket match match* match-lambda))
-          scribble/core scribble/html-properties scribble/eval racket/sandbox
+           (only-in rosette/base/base vc clear-vc! bitvector ~>)
+           (only-in rosette/base/core/reflect symbolics concrete? symbolic?)
+           rosette/base/core/forall racket)
+          scribble/core scribble/html-properties scribble/example racket/sandbox
           "../util/lifted.rkt")
 
 
@@ -18,30 +15,37 @@
 
 @title[#:tag "sec:value-reflection"]{Reflecting on Symbolic Values}
 
-There are two kinds of symbolic values in Rosette:  symbolic terms and 
-symbolic unions.  A Rosette program can inspect the representation of 
-both kinds of values.  This is useful for @tech[#:key "lifted constructs"]{lifting} additional 
-(unlifted) Racket procedures to work on symbolic values, and for 
-controlling the performance of Rosette's symbolic evaluator.
+There are two kinds of symbolic values in Rosette: symbolic
+terms and symbolic unions. A Rosette program can inspect the
+representation of both kinds of values. This is useful for
+@tech[#:key "lifted constructs"]{lifting} additional
+(unlifted) Racket procedures to work on symbolic values, and
+for controlling the performance of Rosette's symbolic
+evaluator.
 
 @section[#:tag "sec:symbolic-terms"]{Symbolic Terms}
 
-@declare-exporting[rosette/base/core/term rosette/base/core/reflect #:use-sources (rosette/base/core/type rosette/base/core/term rosette/base/core/reflect)]
+@declare-exporting[rosette/base/core/term rosette/base/core/reflect
+                   #:use-sources (rosette/base/core/type rosette/base/core/term rosette/base/core/reflect)]
 
-A @deftech{symbolic term} is either a symbolic constant, created via
-@seclink["sec:symbolic-constants"]{@code{define-symbolic[*]}}, 
+A @deftech{symbolic term} is either a symbolic constant,
+created via @seclink["sec:symbolic-constants"]{@code{define-symbolic[*]}},
 or a symbolic expression, produced by a lifted operator.
 Terms are strongly typed, and always belong to a @tech{solvable type}.
-Symbolic values of all other (@tech[#:key "unsolvable type"]{unsolvable}) types take the form of 
-@seclink["sec:symbolic-unions"]{symbolic unions}.
+Symbolic values of all other
+(@tech[#:key "unsolvable type"]{unsolvable}) types take the
+form of @seclink["sec:symbolic-unions"]{symbolic unions}.
 
 @deftogether[(@defproc[(term? [v any/c]) boolean?]
               @defproc[(expression? [v any/c]) boolean?]
               @defproc[(constant? [v any/c]) boolean?])]{
-Predicates for recognizing symbolic terms, expressions, and constants, respectively.
+                                                         
+ Predicates for recognizing symbolic terms, expressions, and
+ constants, respectively.
+
 @examples[#:eval rosette-eval
-(code:line (define-symbolic x integer?) (code:comment "constant"))
-(code:line (define e (+ x 1)) (code:comment "expression"))
+(code:line (define-symbolic x integer?) (code:comment "Constant."))
+(code:line (define e (+ x 1))           (code:comment "Expression."))
 (list (term? x) (term? e))
 (list (constant? x) (constant? e))
 (list (expression? x) (expression? e))
@@ -52,10 +56,13 @@ Predicates for recognizing symbolic terms, expressions, and constants, respectiv
 @deftogether[(@defform[(term content type)]
               @defform[(expression op child ...+)]
               @defform[(constant id type)])]{
-Pattern matching forms for symbolic terms, expressions, and constants, respectively.
+                                             
+ Pattern matching forms for symbolic terms, expressions, and
+ constants, respectively.
+
 @examples[#:eval rosette-eval
-(code:line (define-symbolic x integer?) (code:comment "constant"))
-(code:line (define e (+ x 1)) (code:comment "expression"))
+(code:line (define-symbolic x integer?) (code:comment "Constant."))
+(code:line (define e (+ x 1))           (code:comment "Expression."))
 (match x
   [(constant identifier type) (list identifier type)])
 (match x
@@ -66,19 +73,41 @@ Pattern matching forms for symbolic terms, expressions, and constants, respectiv
   [(term content type) (list content type)])]}
 
 @defproc[(symbolics [v any/c]) (listof constant?)]{
+                                                   
 Returns all symbolic constants that are
 transitively contained in the given value.
+
 @examples[#:eval rosette-eval
 (define-symbolic x y z integer?) 
 (symbolics x)
 (symbolics (if (= x y) 2 #f))
 (symbolics (list y z y))
 (struct cell (value) #:transparent)
+(symbolics (list (vector (box 1) 3) (cell (cons 4 5))))
 (symbolics (list 5 (cons (box y) z) (vector (cell x) z)))]
 }
 
+@defproc[(concrete? [v any/c]) boolean?]{
+Equivalent to @racket[(null? (symbolics v))] but more efficient.
+@examples[#:eval rosette-eval
+(define-symbolic x y z integer?) 
+(concrete? x)
+(concrete? (if (= x y) 2 #f))
+(concrete? (list y z y))
+(struct cell (value) #:transparent)
+(concrete? (list (vector (box 1) 3) (cell (cons 4 5))))
+(concrete? (list 5 (cons (box y) z) (vector (cell x) z)))]              
+}
+
+@defproc[(symbolic? [v any/c]) boolean?]{
+Equivalent to @racket[(not (concrete? v))].
+}
+
 @defproc*[([(type-of [v any/c] ...+) type?])]{
-Returns the most specific @racket[type?] predicate that accepts all of the given values.
+                                              
+ Returns the most specific @racket[type?] predicate that
+ accepts all of the given values.
+                          
 @examples[#:eval rosette-eval
 (define-symbolic x integer?)
 (type-of x) 
@@ -89,8 +118,12 @@ Returns the most specific @racket[type?] predicate that accepts all of the given
 }
 
 @defproc[(type? [v any/c]) boolean?]{
-Returns true when given a predicate that recognizes a @seclink["ch:built-in-datatypes"]{built-in} or
-a @seclink["ch:programmer-defined-datatypes"]{structure} type.  Otherwise returns false.
+                                     
+ Returns true when given a predicate that recognizes a
+ @seclink["ch:built-in-datatypes"]{built-in} or a
+ @seclink["ch:programmer-defined-datatypes"]{structure} type.
+ Otherwise returns false.
+
 @examples[#:eval rosette-eval
 (type? integer?)
 (type? boolean?)
@@ -102,12 +135,15 @@ a @seclink["ch:programmer-defined-datatypes"]{structure} type.  Otherwise return
 }
 
 @defproc[(solvable? [v any/c]) boolean?]{
-Returns true if @racket[v] is a type predicate for a @tech{solvable type}.                                        
+                                         
+ Returns true if @racket[v] is a type predicate for a @tech{solvable type}.
+                
 @examples[#:eval rosette-eval
 (solvable? boolean?)
 (solvable? integer?)
 (solvable? real?)
-(solvable? (~> (bitvector 3) (bitvector 4)))
+(solvable? (bitvector 8))
+(solvable? (~> (bitvector 32) (bitvector 64)))
 (solvable? list?)
 (struct circle (radius))
 (solvable? circle?)
@@ -118,14 +154,20 @@ Returns true if @racket[v] is a type predicate for a @tech{solvable type}.
 
 @declare-exporting[rosette/base/core/union #:use-sources (rosette/base/core/union)]
 
-Rosette represents symbolic values of an @tech[#:key "unsolvable type"]{unsolvable type}
-(e.g., @racket[list?]) as @deftech[#:key "symbolic union"]{symbolic unions}.
-A symbolic union is a set of two or more @deftech[#:key "guarded value"]{guarded values}.
-A guarded value, in turn, combines a guard, which is a symbolic @racket[boolean?] term,
-and a (non-union) value.  Rosette's symbolic evaluator guarantees that the guards in
-a symbolic union are disjoint:  only one of them can ever be true.   For example, the
-symbolic vector @racket[s] defined below is represented as a symbolic union of two guarded vectors:
-@interaction[#:eval rosette-eval
+Rosette represents symbolic values of an
+@tech[#:key "unsolvable type"]{unsolvable type} (e.g.,
+@racket[list?]) as @deftech[#:key "symbolic union"]{symbolic unions}.
+A symbolic union is a set of two or more
+@deftech[#:key "guarded value"]{guarded values}. A guarded
+value, in turn, combines a guard, which is a symbolic
+@racket[boolean?] term, and a (non-union) value. Rosette's
+symbolic evaluator guarantees that the guards in a symbolic
+union are disjoint: only one of them can ever be true. For
+example, the symbolic vector @racket[s] defined below is
+represented as a symbolic union of two guarded vectors:
+
+
+@examples[#:eval rosette-eval #:label #f
 (define-symbolic b boolean?)
 (define v (vector 1))
 (define w (vector 2 3))
@@ -135,27 +177,39 @@ s
 (eq? s v)
 (eq? s w)]
 
-The values that appear in a union are themselves never unions.  They may, however, contain unions.
-They may also belong to several different types.  In that case, the type of the union is the most
-specific @racket[type?] predicate that accepts all members of the union.
-This will always be an unsolvable type---possibly @racket[any/c], the most general unsolvable type.
-@interaction[#:eval rosette-eval
+The values that appear in a union are themselves never
+unions. They may, however, contain unions. They may also
+belong to several different types. In that case, the type of
+the union is the most specific @racket[type?] predicate that
+accepts all members of the union. This will always be an
+unsolvable type---possibly @racket[any/c], the most general
+unsolvable type.
+
+@examples[#:eval rosette-eval #:label #f
 (define-symbolic b boolean?)
 (define-symbolic c boolean?)
 (define v (if c "c" 0))
 (define u (if b (vector v) 4))
 u
-(type-of u)]
+(type-of u)
+(union-contents u)]
 
-Symbolic unions are recognized by the @racket[union?] predicate, and Rosette programs can inspect
-union contents using the @racket[union-contents] procedure. Applications may use @racket[union?] and  
-@racket[union-contents] directly to @tech[#:key "lifted constructs"]{lift} Racket code to work on
-symbolic unions, but Rosette also provides dedicated lifting constructs, described in
-the @seclink["sec:lifting-constructs"]{next section},
-to make this process easier and the resulting lifted code more efficient.
+Symbolic unions are recognized by the @racket[union?]
+predicate, and Rosette programs can inspect union contents
+using the @racket[union-contents] procedure. Applications
+may use @racket[union?] and @racket[union-contents] directly
+to @tech[#:key "lifted constructs"]{lift} Racket code to
+work on symbolic unions, but Rosette also provides dedicated
+lifting constructs, described in the
+@seclink["sec:lifting-constructs"]{next section}, to make
+this process easier and the resulting lifted code more
+efficient.
 
 @defproc[(union? [v any/c]) boolean?]{
-Returns true if the given value is a symbolic union.  Otherwise returns false.  
+                                      
+ Returns true if the given value is a symbolic union.
+ Otherwise returns false.
+
 @examples[#:eval rosette-eval
 (define-symbolic b boolean?)
 (define u (if b '(1 2) 3))
@@ -164,128 +218,192 @@ Returns true if the given value is a symbolic union.  Otherwise returns false.
 }
 
 @defproc[(union-contents [u union?]) (listof (cons/c (and/c boolean? term?) (not/c union?)))]{
-Returns a list of guard-value pairs contained in the given union.  
+                                                                                              
+ Returns a list of guard-value pairs contained in the given
+ union.
+
 @examples[#:eval rosette-eval
 (define-symbolic b boolean?)
 (define v (if b '(1 2) 3))
 (union-contents v)]
 }
 
+
 @section[#:tag "sec:lifting-constructs"]{Symbolic Lifting}
 
-Rosette provides two main constructs for @tech[#:key "lifted constructs"]{lifting}
-Racket code to work on symbolic unions: @racket[for/all] and @racket[define-lift].
-The @racket[for/all] construct is built into the language. It is used internally by Rosette 
-to lift operations on @tech[#:key "unsolvable type"]{unsolvable types}.  The
-@racket[define-lift] construct is syntactic sugar implemented on top of
-@racket[for/all]; it is exported by the @racket[rosette/lib/lift] library.
-
-@declare-exporting[rosette/base/core/forall rosette/lib/lift
-                   #:use-sources (rosette/base/core/forall rosette/lib/lift)]
-
-@defform[(for/all ([id val-expr]) body ...+)]{
-If @racket[val-expr] evaluates to a value that is not a @racket[union?], 
-@racket[for/all] behaves like a @racket[let] expression.  It binds 
-@racket[id] to the value and evaluates the @racket[body] with that binding.  
-
-If @racket[val-expr] evaluates to a symbolic union, then for each 
-guard-value pair @racket['(#, @var[g] . #, @var[v])] in that union, @racket[for/all]  
-binds @racket[id] to @var[v] and evaluates the @racket[body] 
-under the guard @var[g].  The results of the individual evaluations of 
-the @racket[body] are re-assembled into a single (concrete or symbolic) 
-output value, which is the result of the @racket[for/all] expression. 
-If the evaluation of @racket[body] executes any procedure @var[p] that is neither  
-implemented in nor provided by the @racket[rosette/safe] language, then @var[p] 
-@bold{must be pure}---it may not perform any observable side-effects, 
-such as writes to memory or disk.  There is no purity requirement for using procedures
-that are implemented in or exported by @racket[rosette/safe] (e.g., @racket[vector-set!]).
+Rosette provides a construct, @racket[for/all], for
+controlling how symbolic evaluation is performed. This
+construct is built into the language. It is used internally
+by Rosette to @tech[#:key "lifted constructs"]{lift}
+operations on @tech[#:key "unsolvable type"]{unsolvable
+ types}. Rosette programs can also use it for this purpose,
+as well as for tuning the performance of symbolic
+evaluation.
 
 
-The @racket[for/all] construct is useful both for lifting pure Racket procedures to work 
-on symbolic unions and for controling the performance of Rosette's symbolic evaluation. 
-The following examples show both use cases:
+@declare-exporting[rosette/base/core/forall
+                   #:use-sources (rosette/base/core/forall)]
 
-@itemlist[
-@item{@emph{Lifting a pure Racket procedure 
-to work on symbolic unions.}  
+@defform[(for/all ([id val-expr maybe-exhaustive]) body ...+)
+         #:grammar [(maybe-exhaustive (code:line) #:exhaustive)]]{
 
-@defs+int[#:eval rosette-eval
-[(require (only-in racket [string-length racket/string-length]))
+ Splits the evaluation of @racket[body ...+] into multiple
+ paths, based on the value of @racket[val-expr]. In
+ particular, @racket[for/all] evaluates @racket[val-expr],
+ decomposes the resulting value @var{V} into a list of
+ guard-value pairs @racket[(g v) ...+], and evaluates the equivalent of
+ the following expression:
+ @(racketblock
+   (cond [g (let ([id v]) body ...)] ...))
 
-(define (string-length value)
+ The keyword @racket[#:exhaustive] controls the
+ decomposition of @var{V}.
+ 
+ When @racket[#:exhaustive] is omitted, @var{V} is decomposed into
+ @racket[(union-contents #, @var{V})] if it is a symbolic
+ union. Otherwise, it is decomposed trivially into
+ @racket[(list (cons #t #, @var{V}))].
+ 
+ @examples[#:eval rosette-eval
+ (define-symbolic b boolean?)
+
+ (define u (if b (list 1 2) (list 3)))
+ (code:line
+ u                      (code:comment "u is a symbolic union,"))
+ (for/all ([v u])       (code:comment "so the body of for/all is evaluated")
+   (printf "~a, " (vc)) (code:comment "under each of its guards,")
+   (printf "~a\n" v)    (code:comment "with the corresponding value bound to v.")
+   (map add1 v))
+
+ (vc)
+ 
+ (define i (if b 5 10))
+ (code:line
+ i                      (code:comment "i is not a union,"))
+ (for/all ([v i])       (code:comment "so the body of for/all is evaluated")
+   (printf "~a, " (vc)) (code:comment "once under the trival #t guard,")
+   (printf "~a\n" v)    (code:comment "with i itself bound to v.")
+   (add1 v))
+
+ (vc)]
+
+ When @racket[#:exhaustive] is included, @var{V} is
+ decomposed into its constituent guard-value pairs
+ recursively if it is either a union or a conditional
+ symbolic term. Otherwise, it is decomposed trivally.
+          
+ @examples[#:eval rosette-eval
+ (code:comment "i is a conditional term, so with #:exhaustive, it is")
+ (code:comment "split into its constituent guard-value pairs.")
+ (for/all ([v i #:exhaustive]) 
+   (printf "~a, " (vc))     
+   (printf "~a\n" v)     
+   (add1 v))
+ (code:comment "The #:exhaustive decomposition is done recursively,")
+ (code:comment "until no more decomposable terms are left.")
+ (define-symbolic a c boolean?)
+ (define j (if c i 0))
+ j
+ (define u (if a (list 1 2) j))
+ u
+ (for/all ([v u #:exhaustive]) 
+   (printf "~a, " (vc))     
+   (printf "~a\n" v)     
+   (add1 v))
+ (code:comment "The path guarded by a leads to failure,")
+ (code:comment "as reflected in the resulting vc.")
+ (vc)
+ (clear-vc!)
+ (code:comment "The above for/all expression outputs a term")
+ (code:comment "that is syntactically different from but")
+ (code:comment "semantically equivalent to the output of (add1 u),")
+ (code:comment "with the same effect on the vc.")
+ (add1 u)
+ (vc)
+ (clear-vc!)]
+
+ Programs can use @racket[for/all] to lift pure Racket
+ procedures to work on symbolic values and to control the performance
+ of Rosette's symbolic evaluation.
+
+ For example, the following snippet shows how to use
+ @racket[for/all] to lift @racket[string-length]
+ to work on symbolic strings. This approach
+ generalizes to all unlifted datatypes, since their
+ symbolic representation is always a union of guarded
+ concrete values.
+
+ @examples[#:eval rosette-eval #:label #f
+
+ (eval:no-prompt
+  (require (only-in racket [string-length racket/string-length])))
+
+ (eval:no-prompt
+  (define (string-length value)
     (for/all ([str value]) 
-    (racket/string-length str)))]
+      (racket/string-length str))))
 
-(string-length "abababa")
-(string-length 3)
-(define-symbolic b boolean?)
-(string-length (if b "a" "abababa"))
-(string-length (if b "a" 3))
-(asserts)
-(string-length (if b 3 #f))]}
+  (string-length "abababa")
+  (eval:error (string-length 3))
+  (define-symbolic b boolean?)
+  (string-length (if b "a" "abababa"))
+  (vc)
+  (string-length (if b "a" 3))
+  (vc)
+  (clear-vc!)]
 
-@item{@emph{Making symbolic evaluation more efficient.}  @(rosette-eval '(clear-asserts!))
-@defs+int[#:eval rosette-eval
-[(require (only-in racket build-list))
+ Here is also an example of using @racket[for/all] for
+ performance tuning. Note that adding @racket[for/all]s in
+ too many places, or in the wrong places, will lead to worse
+ performance. @seclink["ch:performance"]{Profiling} is the
+ best way to determine whether and where to insert them.
 
-(define limit 1000) 
+ @examples[#:eval rosette-eval #:label #f
+ (eval:no-prompt
+  (require (only-in racket build-list)))
  
-(define (slow xs)
-  (and (= (length xs) limit) (car (map add1 xs))))
+ (eval:no-prompt
+  (define (vector-update! v idx proc)  (code:comment "v[idx] := proc(v[idx])")
+    (vector-set! v idx (proc (vector-ref v idx)))))
  
-(define (fast xs)
-  (for/all ([xs xs]) (slow xs)))
+ (eval:no-prompt
+  (define (vector-update!! v idx proc) 
+    (for/all ([idx idx #:exhaustive])  (code:comment "Split paths based on idx.")
+      (vector-update! v idx proc))))
 
-(define ys (build-list limit identity))
+ (define-symbolic a b boolean?)
+ (define idx (if a 0 (if b 5 10)))
+ (define limit 10000)
+ (code:line (define vals (build-list limit identity)) (code:comment "'(0 1 ... 9999)"))
 
-(define-symbolic a boolean?)
+ (code:comment "vector-update! is 2 orders of magnitude slower than")
+ (code:comment "vector-update!! on the following tests.")
+ (code:comment "By default, Rosette treats idx as an opaque symbolic")
+ (code:comment "integer when evaluating vector-update!, so it must")
+ (code:comment "account for the possibility of idx taking on any value")
+ (code:comment "between 0 and limit. The for/all in vector-update!!")
+ (code:comment "instructs Rosette to split the index and consider only")
+ (code:comment "the values that idx can in fact take on: 0, 5, 10.")
+ (define v0 (list->vector vals))
+ (time (vector-update! v0 idx add1))
+ (define v1 (list->vector vals))
+ (time (vector-update!! v1 idx add1))
+ (code:comment "But the default evaluation strategry is better for indices")
+ (code:comment "that are fully symbolic conditional terms.")
+ (define-symbolic i0 i1 i2 i3 integer?)
+ (define idx (if a (if b i0 i1) (if b i2 i3)))
+ (define v2 (list->vector vals))
+ (time (vector-update! v2 idx add1))
+ (define v3 (list->vector vals))
+ (time (vector-update!! v3 idx add1))]}
 
-(define xs (if a ys (cdr ys)))]
+@defform[(for*/all ([id val-expr maybe-exhaustive]) body ...+)
+         #:grammar [(maybe-exhaustive (code:line) #:exhaustive)]]{
                                                     
-(time (slow xs))
-(time (fast xs))]
+ Expands to a nested use of @racket[for/all], just like
+ @racket[let*] expands to a nested use of @racket[let].
 
-Note that the above transformation will not always lead to better performance.  
-Experimenting is the best way to determine whether and where to insert  
-performance-guiding @racket[for/all]s.
-}]}
-
-@defform[(for*/all ([id val-expr] ...+) body ...+)]{
-Expands to a nested use of @racket[for/all], 
-just like @racket[let*] expands to a nested use of @racket[let].}                                             
-                                    
-@defmodule[rosette/lib/lift #:no-declare]
-
-@defform*[((define-lift id [(arg-type ...) racket-procedure-id])
-           (define-lift id [arg-type racket-procedure-id]))]{
-Binds @racket[id] to a procedure that lifts @racket[racket-procedure-id]  to 
-work on symbolic unions.  In particular, the lifted procedure will work when given 
-either a concrete Racket value or a symbolic union contains a guarded value of 
-a suitable type, as given by @racket[arg-type].  Note that the lifted procedure 
-will not work on symbolic terms, only on symbolic unions or concrete values.  The 
-Racket procedure bound to @racket[racket-procedure-id] must be pure (see @racket[for/all]).
-
-When @racket[racket-procedure-id] takes a specific number of arguments, 
-the first form should be used, and the type of each argument should be given.
-When @racket[racket-procedure-id] takes a variable number of arguments, 
-the type of all arguments should be given.  Note that the second form omits 
-the parentheses around the argument type to indicate a variable number of 
-arguments, just like Racket's @racket[case-lambda] form.
-
-The following example shows how to lift Racket's @racket[string-length] procedure 
-to work on symbolic unions that contain strings.   
-
-@defs+int[#:eval rosette-eval
-[(require rosette/lib/lift)
-(require (only-in racket [string-length racket/string-length] string?))
-
-(define-lift string-length [(string?) racket/string-length])]
-
-(string-length "abababa")
-(define-symbolic b boolean?)
-(string-length (if b "a" "abababa"))
-(string-length (if b "a" 3))
-(asserts)]
 }                                             
                                                          
+
 @(kill-evaluator rosette-eval)

rosette/guide/scribble/refs.scrbl

@@ -9,21 +9,28 @@
 
 @(define rosette:onward13
    (make-bib
-     #:title @hyperlink["http://homes.cs.washington.edu/~emina/pubs/rosette.onward13.pdf"]{Growing Solver-Aided Languages with Rosette}
+     #:title @hyperlink["http://dl.acm.org/citation.cfm?id=2509586"]{Growing Solver-Aided Languages with Rosette}
      #:author (authors "Emina Torlak" "Rastislav Bodik")
      #:date 2013
      #:location "New Ideas, New Paradigms, and Reflections on Programming and Software (Onward!)"))
 
 @(define rosette:pldi14
    (make-bib
-    #:title @hyperlink["http://homes.cs.washington.edu/~emina/pubs/rosette.pldi14.pdf"]{A Lightweight Symbolic Virtual Machine for Solver-Aided Host Languages}
+    #:title @hyperlink["http://dl.acm.org/citation.cfm?id=2594340"]{A Lightweight Symbolic Virtual Machine for Solver-Aided Host Languages}
     #:author (authors "Emina Torlak" "Rastislav Bodik")
     #:date 2014
     #:location "Programming Language Design and Implementation (PLDI)"))
 
 @(define sympro:oopsla18
    (make-bib
-    #:title @hyperlink["https://unsat.cs.washington.edu/papers/bornholt-sympro.pdf"]{Finding Code That Explodes Under Symbolic Evaluation}
+    #:title @hyperlink["https://dl.acm.org/citation.cfm?id=3276519"]{Finding Code That Explodes Under Symbolic Evaluation}
     #:author (authors "James Bornholt" "Emina Torlak")
     #:date 2018
     #:location "Object Oriented Programming, Systems, Languages, and Applications (OOPSLA)"))
+
+@(define rosette:popl22
+   (make-bib
+    #:title @hyperlink["https://doi.org/10.1145/3498709"]{A Formal Foundation for Symbolic Evaluation with Merging}
+    #:author (authors "Sorawee Porncharoenwase" "Luke Nelson" "Xi Wang" "Emina Torlak")
+    #:date 2022
+    #:location "Principles of Programming Languages (POPL)"))

rosette/guide/scribble/unsafe/unsafe-log.txt

@@ -14,19 +14,41 @@
   0
   ()
   ()
-  (c values c (v! 0 (0 (u . "(ite b 3 1)")) (0 (u . "(ite b 2 4)")))))
+  (c values c (0 (u . "(vector 0 (ite b 3 1) (ite b 2 4))\n"))))
  #""
  #"")
-((define env1 (solve (assert b)))
+((define sol1 (solve (assert b)))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate y env1) ((3) 0 () 0 () () (c values c (v! 0 3 2))) #"" #"")
-((define env2 (solve (assert (not b))))
+((evaluate y sol1)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#(0 3 2)\n"))))
+ #""
+ #"")
+((define sol2 (solve (assert (not b))))
  ((3) 0 () 0 () () (c values c (void)))
  #""
  #"")
-((evaluate y env2) ((3) 0 () 0 () () (c values c (v! 0 1 4))) #"" #"")
+((evaluate y sol2)
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#(0 1 4)\n"))))
+ #""
+ #"")
 ((require (only-in racket make-hash hash-clear! hash-ref))
  ((3) 0 () 0 () () (c values c (void)))
  #""
@@ -38,5 +60,19 @@
 ((define-symbolic key integer?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((define-symbolic b boolean?) ((3) 0 () 0 () () (c values c (void))) #"" #"")
 ((hash-ref h key 0) ((3) 0 () 0 () () (q values 0)) #"" #"")
-((when b (hash-clear! h)) ((3) 0 () 0 () () (c values c (void))) #"" #"")
-(h ((3) 0 () 0 () () (c values c (h ! (equal)))) #"" #"")
+((when b (pretty-print (vc)) (hash-clear! h))
+ ((3) 0 () 0 () () (c values c (void)))
+ #"(vc b #t)\n"
+ #"")
+(h
+ ((3)
+  1
+  (((lib "rosette/guide/scribble/util/lifted.rkt")
+    .
+    deserialize-info:opaque-v0))
+  0
+  ()
+  ()
+  (c values c (0 (u . "'#hash()\n"))))
+ #""
+ #"")

rosette/guide/scribble/unsafe/unsafe.scrbl

@@ -1,11 +1,10 @@
 #lang scribble/manual
 
-@(require (for-label racket) scribble/core scribble/eval)
+@(require (for-label racket) scribble/core scribble/example)
 @(require (for-label rosette/base/form/define rosette/query/query rosette/solver/solution
-                     rosette/base/core/term (only-in rosette/query/debug define/debug debug)
-                     (only-in rosette/base/core/safe assert) )
-          racket/runtime-path)
-@(require (only-in "../refs.scrbl" ~cite rosette:pldi14))
+                     (only-in rosette/base/base assert vc-true? vc) )
+          racket/runtime-path racket/sandbox)
+@(require (only-in "../refs.scrbl" ~cite rosette:pldi14 rosette:popl22))
 @(require "../util/lifted.rkt")
 
 @(define-runtime-path root ".")
@@ -14,24 +13,24 @@
 @title[#:tag "ch:unsafe"]{Unsafe Operations}
 
 Throughout this guide, we have assumed that Rosette programs are 
-written in the @racket[rosette/safe] dialect of the full language.  
+written in the @racketmodname[rosette/safe] dialect of the full language.
 This dialect extends a core subset of Racket with @seclink["ch:essentials"]{solver-aided 
-functionality}.  In this chapter, we briefly discuss the @racket[rosette] 
+functionality}.  In this chapter, we briefly discuss the @racketmodname[rosette]
 dialect of the language, which exports all of Racket.  
 
-Safe use of the full @racket[rosette] language requires a basic understanding 
-of how Rosette's Symbolic Virtual Machine (SVM) works  @~cite[rosette:pldi14].  
+Safe use of the full @racketmodname[rosette] language requires a basic understanding
+of how Rosette's Symbolic Virtual Machine (SVM) works  @~cite[rosette:pldi14 rosette:popl22].  
 Briefly, the SVM hijacks the normal Racket execution for all procedures and 
-constructs that are exported by @racket[rosette/safe].  Any programs that are 
-implemented exclusively in the @racket[rosette/safe] language are therefore 
+constructs that are exported by @racketmodname[rosette/safe].  Any programs that are
+implemented exclusively in the @racketmodname[rosette/safe] language are therefore
 fully under the SVM's control.  This means that the SVM can correctly interpret 
 the application of a procedure or a macro to a symbolic value, and it 
 can correctly handle any side-effects (in particular, writes to memory) performed 
-by @racket[rosette/safe] code.
+by @racketmodname[rosette/safe] code.
 
 The following snippet demonstrates the non-standard execution that the SVM needs to 
 perform in order to assign the expected meaning to Rosette code:
-@interaction[#:eval rosette-eval
+@examples[#:eval rosette-eval
 (define y (vector 0 1 2))
  
 (define-symbolic b boolean?)
@@ -48,31 +47,31 @@ perform in order to assign the expected meaning to Rosette code:
 
 y
 
-(define env1 (solve (assert b)))
-(evaluate y env1)
+(define sol1 (solve (assert b)))
+(evaluate y sol1)
 
-(define env2 (solve (assert (not b))))
-(evaluate y env2)]
+(define sol2 (solve (assert (not b))))
+(evaluate y sol2)]
 
-Because the SVM controls only the execution of @racket[rosette/safe] code, 
-it cannot, in general, guarantee the safety or correctness of arbitrary @racket[rosette] programs. 
-As soon as a @racket[rosette] program calls an @tech[#:key "lifted construct"]{unlifted} Racket construct  
-(that is, a procedure or a macro not implemented in or provided by the @racket[rosette/safe] language), 
+Because the SVM controls only the execution of @racketmodname[rosette/safe] code,
+it cannot, in general, guarantee the safety or correctness of arbitrary @racketmodname[rosette] programs.
+As soon as a @racketmodname[rosette] program calls an @tech[#:key "lifted construct"]{unlifted} Racket construct
+(that is, a procedure or a macro not implemented in or provided by the @racketmodname[rosette/safe] language),
 the execution escapes back to the Racket interpreter.  The SVM has no control over the side-effects 
 performed by the Racket interpreter, or the meaning that it (perhaps incorrectly) assigns to programs 
 in the presence of symbolic values.  As a result, the programmer is responsible for ensuring that 
-a @racket[rosette] program continues to behave correctly after the execution returns from the Racket interpreter.
+a @racketmodname[rosette] program continues to behave correctly after the execution returns from the Racket interpreter.
 
-As an example of incorrect behavior, consider the following @racket[rosette] snippet.  
-The procedures @racket[make-hash], @racket[hash-ref], and @racket[hash-clear!] are not in @racket[rosette/safe].
+As an example of incorrect behavior, consider the following @racketmodname[rosette] snippet.
+The procedures @racket[make-hash], @racket[hash-ref], and @racket[hash-clear!] are not in @racketmodname[rosette/safe].
 Whenever they are invoked, the execution escapes to the Racket interpreter.
 
 @(rosette-eval '(require (only-in racket make-hash hash-clear! hash-ref)))
-@defs+int[#:eval rosette-eval
+@examples[#:eval rosette-eval
 
-[(define h (make-hash '((1 . 2))))
+(define h (make-hash '((1 . 2))))
 (define-symbolic key integer?)
-(define-symbolic b boolean?)]
+(define-symbolic b boolean?)
 
 
 (code:comment "The following call produces an incorrect value. Intuitively, we expect the")
@@ -84,6 +83,7 @@ Whenever they are invoked, the execution escapes to the Racket interpreter.
 (code:comment "The following call produces an incorrect state. Intuitively, we expect h")
 (code:comment "to be empty if b is true and unchanged otherwise.")
 (when b
+  (pretty-print (vc))
   (hash-clear! h))
 h]  
 
@@ -91,12 +91,12 @@ When is it safe to use a Racket procedure or macro?  The answer depends on their
 A conservative rule is to only use an unlifted construct @var[c] in an @deftech{effectively concrete} @tech{program state}. 
 The SVM is in such a state when 
 @itemlist[#:style 'ordered
-  @item{the current @tech{path condition} is @racket[#t];}
-  @item{the @tech{assertion store} is empty; and,}
+  @item{the current @tech{verification condition} is true, i.e., @racket[(vc-true? (vc))]; and,}
   @item{all local and global variables that may be read by @var[c] contain @deftech{fully concrete value}s. A  
 value (e.g., a list) is fully concrete if no symbolic values can be reached by recursively traversing its structure.}] 
-The two uses of @racket[hash-ref] and @racket[hash-clear!] in our buggy example violate the third and first 
-requirements, respectively.
+The above uses of @racket[hash-ref] and @racket[hash-clear!] violate these 
+requirements: @racket[hash-ref] is reading a symbolic value, and @racket[hash-clear!] is
+evaluated in a state with a symbolic verification condition.
 
 Being conservative, the above rule disallows many scenarios in which it is still safe to use 
 Racket constructs.  These, however, have to be considered on a case-by-case basis.  For example, 
@@ -104,3 +104,5 @@ it is safe to use Racket's iteration and comprehension constructs, such as @rack
 as long as they iterate over concrete sequences, and all guard expressions produce fully concrete values in 
 each iteration.  In practice, Rosette programs can safely use many common Racket constructs, and with a 
 bit of experience, it becomes easy to see when it is okay to break the effectively-concrete rule.
+
+@(kill-evaluator rosette-eval)

rosette/guide/scribble/util/demo.rkt

@@ -0,0 +1,29 @@
+#lang rosette
+
+(provide demo define-demo print-forms-alt)
+
+(define-syntax-rule (demo form)
+  (begin
+    (printf "> ~a\n" 'form)
+    (with-handlers ([exn:fail? (lambda (e)
+                                 (eprintf "~a\n" (exn-message e))
+                                 (clear-vc!)
+                                 (solver-shutdown (current-solver)))])
+      (let ([v form])
+        (unless (void? v)
+          (printf "~a\n" v))))))
+
+(define-syntax-rule (define-demo id form ...)
+  (define (id)
+    (printf "\n--------~a--------\n" 'id)
+    form ...))
+
+(require (only-in rosette/lib/synthax generate-forms))
+
+(define (print-forms-alt sol)
+  (define stxs (generate-forms sol))
+  (pretty-write (syntax->datum (car stxs)))
+  (for ([stx (cdr stxs)])
+    (newline)
+    (pretty-write (syntax->datum stx))))
+

rosette/guide/scribble/util/lifted.rkt

@@ -1,10 +1,10 @@
 #lang racket
 
-(provide select rosette-evaluator rosette-log-evaluator logfile opaque)
+(provide select rosette-evaluator rosette-log-evaluator logfile opaque format-opaque)
 
 (require 
   (for-label racket racket/generic)
-  (only-in rosette rosette union union-contents union?)
+  (only-in rosette rosette bv)
   racket/sandbox racket/serialize scribble/eval
   (only-in scribble/manual elem racket))
 
@@ -16,15 +16,6 @@
    (apply elem 
           (add-between (map (lambda (id) (racket #,#`#,id)) 
                             (filter lifted? racket-ids)) ", ")))
-(define (rosette-printer v)
-  (match v
-    [(? void?) (void)]
-    [(? custom-write?) 
-     ((custom-write-accessor v) v (current-output-port) 1)]
-    [(? pair?) (printf "'~a" v)]
-    [(? null?) (printf "'()")]
-    [(? symbol?) (printf "'~a" v)]
-    [_  (printf "~a" v)]))
 
 (define (rosette-evaluator [eval-limits #f] [lang 'rosette/safe])
    (parameterize ([sandbox-output 'string]
@@ -32,32 +23,35 @@
                   [sandbox-path-permissions `((execute ,(byte-regexp #".*")))]
                   [sandbox-memory-limit #f]
                   [sandbox-eval-limits eval-limits]
-                  [current-print rosette-printer])
+                  [current-print show])
      (make-evaluator lang)))
 
 (define (logfile root [filename "log"])
   (build-path root (format "~a.txt" filename)))
 
-(define (serialize-for-logging v)
-  (match v
-    [(or (? boolean?) (? number?) (? string?) (? void?)) v]
-    [(? box?) (box (serialize-for-logging (unbox v)))]
-    [(? pair?) (cons (serialize-for-logging (car v)) (serialize-for-logging (cdr v)))]
-    [(? list?) (map serialize-for-logging v)]
-    [(? vector?) (list->vector (map serialize-for-logging (vector->list v)))]
-    [(? struct?)
-     (let ([output-str (open-output-string)])
-       (display v output-str)
-       (opaque (get-output-string output-str)))]
-    [_ v]))
-
 (serializable-struct opaque (str)
   #:methods gen:custom-write
   [(define (write-proc self port mode)
      (fprintf port "~a" (opaque-str self)))])
 
+(define (format-opaque format-str . args)
+  (opaque (apply format format-str args)))
+
+(define (serialize-for-logging v)
+  (match v
+    [(or (? boolean?) (? number?) (? string?) (? symbol?) (? void?)) v]
+    [_
+     (define out (open-output-string))
+     (show v out)
+     (opaque (get-output-string out))]))
+
 (define (serializing-evaluator evaluator)
-  (lambda (expr) (serialize-for-logging (evaluator expr))))
+  (lambda (expr)
+    (define v (evaluator expr))
+    (printf "~a" (get-output evaluator))
+    (eprintf "~a" (get-error-output evaluator))
+    (serialize-for-logging v)))
+
 
 (define (rosette-log-evaluator logfile [eval-limits #f] [lang 'rosette/safe])  
   (if (file-exists? logfile)
@@ -65,3 +59,90 @@
       (parameterize ([current-eval (serializing-evaluator (rosette-evaluator eval-limits lang))])
         (make-log-based-eval logfile 'record))))
 
+
+(define (show v [port (current-output-port)])
+  (unless (void? v)
+    (define s (format "~v" v))
+    (cond
+      [(<= (string-length s) (pretty-print-columns))
+       (fprintf port "~a\n" s)]
+      [else 
+       (define out (open-output-string))
+       (parameterize ([read-square-bracket-with-tag #t]
+                      [read-curly-brace-with-tag #t]
+                      [current-readtable tuple-readtable-open])
+         (pretty-write (showable (read (open-input-string s))) out))
+       (let* ([str (get-output-string out)]
+              [str (regexp-replace* #px"\\(⟦\\s*" str "[")]
+              [str (regexp-replace* #px"\\s*⟧\\)" str "]")]
+              [str (regexp-replace* #px"\\(⦃\\s*" str "{")]
+              [str (regexp-replace* #px"\\s*⦄\\)" str "}")])
+         (fprintf port "~a\n" str))])))
+
+(define (showable v)
+  (match v
+    [(list '#%brackets rest ...)
+     `(⟦ ,@(map showable rest) ⟧)]
+    [(list '#%braces rest ...)
+     `(⦃ ,@(map showable rest) ⦄)]
+    [(list 'bv (? integer? x) (? integer? len))
+     (bv x len)]
+    [(? list?)
+     (map showable v)]
+    [_ v]))
+
+; Adapted from https://docs.racket-lang.org/reference/readtables.html
+
+(define (parse-nonempty port read-one src)
+    (let ([ch (peek-char port)])
+      (if (eof-object? ch)
+          null
+          (case ch
+            [(#\>) (read-char port)
+                   null]
+            [else
+             (cons (read-one)
+                   (parse-nonempty port read-one src))]))))
+
+(define (parse port read-one src)
+  (if (eq? #\> (peek-char port))
+      null
+      (cons (read-one)
+            (parse-nonempty port read-one src))))
+
+(define (wrap l)
+  (define out (open-output-string))
+  (fprintf out "#<")
+  (for ([v l])
+    (match v
+      [(list 'unquote w)
+       (fprintf out ", ~a" w)]
+      [_  (fprintf out "~a" v)]))
+  (fprintf out ">")
+  (opaque (get-output-string out)))
+
+
+(define parse-open-tuple
+    (case-lambda
+     [(ch port)
+      (parameterize ([current-readtable (tuple-readtable-close)])
+        (wrap (parse port
+                     (lambda ()
+                       (read/recursive port #f ))
+                     (object-name port))))]
+     [(ch port src line col pos)
+      (datum->syntax
+       #f
+       (parameterize ([current-readtable (tuple-readtable-close)])
+         (wrap (parse port
+                      (lambda ()
+                        (read-syntax/recursive src port #f))
+                      src)))
+       (let-values ([(l c p) (port-next-location port)])
+         (list src line col pos (and pos (- p pos)))))]))
+
+(define tuple-readtable-open
+  (make-readtable #f #\< 'dispatch-macro parse-open-tuple))
+
+(define (tuple-readtable-close)
+  (make-readtable (current-readtable) #\> 'terminating-macro (lambda _ null)))

rosette/guide/scribble/welcome/welcome.scrbl

@@ -16,13 +16,13 @@ Rosette is a @emph{solver-aided} programming system with two components:
                 compiles them to logical constraints.  The SVM enables Rosette 
                 to use the solver to automatically reason about program behaviors.}]
 
-The name "Rosette" refers both to the language and the whole system.
+The name ``Rosette'' refers both to the language and the whole system.
 
 @section[#:tag "sec:get"]{Installing Rosette}
 
 To install Rosette, you will need to
 
-@itemlist[@item{Download and install @hyperlink["http://racket-lang.org"]{Racket} (version 7.0 or later).}
+@itemlist[@item{Download and install @hyperlink["http://racket-lang.org"]{Racket} (version 8.1 or later).}
            @item{Use Racket's @tt{raco} tool to install Rosette:
                  @nested{
                          @verbatim|{> raco pkg install rosette}|}}]
@@ -37,8 +37,8 @@ Example Rosette programs can be found in the @tt{rosette/sdsl} folder.  Most of
 
 The Rosette system ships with two dialects of the Rosette language: 
 
-@itemlist[@item{a @emph{safe} dialect, which is used throughout this guide, and}
-          @item{an @emph{unsafe} dialect, which is briefly described in the @seclink["ch:unsafe"]{last chapter}.}]
+@itemlist[@item{a @emph{safe} dialect, which is used in most of this guide, and}
+          @item{an @emph{unsafe} dialect, which is briefly described in @seclink["ch:unsafe"]{Chapter 8}.}]
 
 
 
@@ -50,5 +50,9 @@ To use the unsafe dialect, type this line instead:
 
 @racketmod[rosette]
 
-We strongly recommend that you start with the safe dialect, which includes a core subset of Racket.  The unsafe dialect includes all of Racket, but unless you understand and observe the restrictions on using non-core features, your seemingly correct programs may crash or produce unexpected results.
-
+We strongly recommend that you start with the safe dialect,
+which includes a core subset of Racket. The unsafe dialect
+includes all of Racket, but unless you understand and
+observe the restrictions on using non-core features,
+seemingly correct programs may crash or produce unexpected
+results.

rosette/info.rkt

@@ -14,10 +14,7 @@
      (experimental))))
      ;; Documentation category. On Racket 6.3+ this can be any string.
 
-;; Runs the code in `private/install.rkt` before installing this collection.
-(define pre-install-collection "private/install.rkt")
-(define compile-omit-files '("private/install.rkt"
-                             "lib/trace/report/node_modules"))
+(define compile-omit-files '("lib/trace/report/node_modules"))
 
 (define raco-commands
   '(("symprofile"

rosette/lib/angelic.rkt

@@ -9,7 +9,7 @@
     [(x) x]
     [(x y) (define-symbolic* x? boolean?)
            (if x? x y)]
-    [xs    (define-symbolic* xi? boolean? [(sub1 (length xs))])
+    [xs    (define-symbolic* xi? boolean? #:length (sub1 (length xs)))
            (let loop ([xi? xi?][xs xs])
              (if (or (null? xi?) (car xi?)) 
                  (car xs)

rosette/lib/destruct.rkt

@@ -0,0 +1,66 @@
+#lang racket
+
+(require syntax/parse/define
+         (only-in rosette for/all for*/all)
+         (for-syntax racket/struct-info racket/list))
+
+(provide destruct-lambda destruct destruct*)
+
+(begin-for-syntax
+  (define-syntax-class sub-pattern
+    #:description "a sub-pattern"
+    (pattern {~or* {~datum _} {~datum ...} {~datum ___}}
+             #:attr id-set '())
+    (pattern x:id
+             #:when (regexp-match #px"^(\\.\\.|__)\\d+$" (symbol->string (syntax-e #'x)))
+             #:attr id-set '())
+    (pattern x:id
+             #:attr id-set (list #'x)))
+
+  (define-syntax-class head-pattern
+    #:description "a head pattern"
+    (pattern {~or* {~datum list}
+                   {~datum list-rest}
+                   {~datum list*}
+                   ;; list-no-order is generally buggy, so let's not include it.
+                   {~datum vector}
+                   {~datum cons}
+                   {~datum box}})
+    ;; structs
+    (pattern x:id #:when (struct-info? (syntax-local-value #'x (λ () #f)))))
+
+  (define-syntax-class clause-pattern
+    (pattern (head:head-pattern expr:sub-pattern ...)
+             #:attr id-set (append* (attribute expr.id-set)))
+    (pattern x:sub-pattern
+             #:attr id-set (attribute x.id-set)))
+
+  (define (check-duplicate-identifier! xs)
+    (define dup-result (check-duplicate-identifier xs))
+    (when dup-result
+      (raise-syntax-error #f "duplicate binding identifier" dup-result))))
+
+(define-simple-macro (destruct-lambda [pat expr ...+] ...)
+  (lambda (v) (destruct v [pat expr ...] ...)))
+
+;; NOTE: we need to wrap the RHS of a clause in `begin` to disallow
+;; the special meaning of => in [_ (=> fail) (fail)]
+
+(define-simple-macro (destruct val [pat:clause-pattern e:expr ...+] ...)
+  #:do [(for-each check-duplicate-identifier! (attribute pat.id-set))]
+  #:with match-expr (syntax/loc this-syntax (match var [pat (begin e ...)] ...))
+  #:with result
+  (syntax/loc this-syntax
+    (for/all ([var val]);(guarded-values val)])
+      match-expr))
+  result)
+
+(define-simple-macro (destruct* (val ...) [(pat:clause-pattern ...) e:expr ...+] ...)
+  #:do [(for-each (λ (xs) (check-duplicate-identifier! (append* xs)))
+                  (attribute pat.id-set))]
+  #:with (var ...) (generate-temporaries #'(val ...))
+  #:with result
+  (syntax/loc this-syntax
+    (for*/all ([var val] ...); (guarded-values val)] ...)
+      (match* (var ...) [(pat ...) (begin e ...)] ...)))
+  result)

rosette/lib/lift.rkt

@@ -1,53 +0,0 @@
-#lang rosette
-
-(require "match.rkt" (for-syntax (only-in racket/syntax generate-temporary))
-         (only-in racket/splicing splicing-let))
-
-(provide define-lift) 
-
-; The define-lift macro lifts a Racket procedure to 
-; work on symbolic union representations of ordinary Racket 
-; values.  This means the lifted procedure will work when given 
-; either a concrete Racket value or a symbolic union that 
-; could evaluate to such a value.  Note that the lifted procedure 
-; will not work on primitive symbolic values (boolean?, integer?, real? and 
-; bitvector?), only on symbolic unions or concrete values.
-;
-; The define-lift macro takes takes one of two forms:
-; * (define-lifted lifted-id [(arg-type ...) procedure-to-lift])
-; * (define-lifted lifted-id [args-type procedure-to-lift])
-;
-; When the procedure to be lifted takes a specific number of arguments, 
-; the first form should be used, and the type of each argument should be given.
-; When the procedure to be lifted takes a variable number of arguments, 
-; the type of all arguments should be given.  Note that the second form omits 
-; the parentheses around the argument type to indicate a variable number of 
-; arguments, just like Racket's case-lambda form.
-(define-syntax (define-lift stx)
-  (syntax-case stx ()
-    [(_ id [type impl])
-     (not (identifier? #'impl))
-     (with-syntax ([tmp (generate-temporary)])
-       (syntax/loc stx 
-         (splicing-let ([tmp impl])
-           (define-lift id [type tmp]))))]
-    [(_ id [(type? ...)  impl])
-     (with-syntax ([(arg ...) (generate-temporaries #'(type? ...))])
-       (syntax/loc stx
-         (define (id arg ...)
-           (match* (arg ...)
-             [((? type? arg) ...) (impl arg ...)]
-             [(arg ...) (error 'id "expected ~a, given ~a" (list type? ...) (list arg ...))]))))]
-    [(_ id [type?  impl])
-     (syntax/loc stx
-       (define id
-         (case-lambda 
-           [()    (impl)]
-           [(x)   (match x 
-                    [(? type? x) (impl x)])]
-           [(x y) (match* (x y)
-                    [((? type? x) (? type? y)) (impl x y)])]
-           [xs    (id (car xs) (apply id (cdr xs)))])))]))
-
-                  
-