From 57f8ac4437ba275b9e0da129c287881793752231 Mon Sep 17 00:00:00 2001
From: Jeremie Dimino <jdimino@janestreet.com>
Date: Mon, 25 Apr 2016 10:50:26 +0100
Subject: [PATCH] make ppx_tools dependency optional

---
 _oasis                    |  4 ++++
 _tags                     |  2 +-
 myocamlbuild.ml           | 10 +++++++++-
 opam                      |  1 +
 src/lib/uTop_main.cppo.ml |  9 +++++++++
 5 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/_oasis b/_oasis
index 17efb91..aa12795 100644
--- a/_oasis
+++ b/_oasis
@@ -33,6 +33,10 @@ Flag camlp4
   Description: camlp4 support
   Default: false
 
+Flag interact
+  Description: enable UTop_main.interact (requires ppx_tools)
+  Default: false
+
 Library utop
   Path: src/lib
   Modules:
diff --git a/_tags b/_tags
index f9c97b0..69721d0 100644
--- a/_tags
+++ b/_tags
@@ -1,6 +1,6 @@
 # -*- conf -*-
 
-<src/**/*.ml{,i}>: cppo_V_OCAML, package(compiler-libs)
+<src/**/*.ml{,i}>: cppo_V_OCAML, cppo_interact, package(compiler-libs)
 <src/camlp5/**/*.ml{,i}>: use_camlp5
 
 <**/*.ml>: warn(-3-40)
diff --git a/myocamlbuild.ml b/myocamlbuild.ml
index b07b545..48063c5 100644
--- a/myocamlbuild.ml
+++ b/myocamlbuild.ml
@@ -89,6 +89,14 @@ let () =
                ~prod:"src/top/uTop_top_full.byte"
                (fun _ _ -> cp "src/top/uTop_top.top" "src/top/uTop_top_full.byte");
 
+
+             let interact_enabled = BaseEnvLight.var_get "interact" env = "true" in
+             flag ["cppo"; "cppo_interact"] (
+               if interact_enabled then
+                 S [A "-D"; A "ENABLE_INTERACT"]
+               else
+                 N);
+
              rule "format lifter"
                ~prod:"src/lib/uTop_cmt_lifter.ml"
                (fun _ _ ->
@@ -96,7 +104,7 @@ let () =
                     Scanf.sscanf (BaseEnvLight.var_get "ocaml_version" env)
                       "%u.%u" (fun a b -> (a, b))
                   in
-                  if ocaml_version < (4, 02) then
+                  if ocaml_version < (4, 02) || not interact_enabled then
                     Echo ([], "src/lib/uTop_cmt_lifter.ml")
                   else
                     Cmd (S [ P "ocamlfind"
diff --git a/opam b/opam
index d57f4f4..c4e8423 100644
--- a/opam
+++ b/opam
@@ -30,5 +30,6 @@ depends: [
 ]
 depopts: [
   "camlp4"
+  "ppx_tools"
 ]
 available: [ ocaml-version >= "4.01" ]
diff --git a/src/lib/uTop_main.cppo.ml b/src/lib/uTop_main.cppo.ml
index 3ea3070..bf134e4 100644
--- a/src/lib/uTop_main.cppo.ml
+++ b/src/lib/uTop_main.cppo.ml
@@ -1373,6 +1373,15 @@ type value = V : string * _ -> value
 let interact ~search_path ~unit ~loc:(fname, lnum, cnum, _) ~values =
   failwith "UTop_main.interact is not supported on OCaml 4.01"
 
+#elif not defined ENABLE_INTERACT
+
+let interact ~search_path ~unit ~loc:(fname, lnum, cnum, _) ~values =
+  failwith "\
+UTop_main.interact wasn't enabled at compile time.
+If you installed utop through opam, just do this to enable this feature:
+
+  $ opam install ppx_tools"
+
 #else
 
 exception Found of Env.t