add standard library / initial environment

bin/main.ml

@@ -5,7 +5,7 @@ let () =
   Logs.set_level (Some Logs.Debug);
 
   try
-    let ast = parse "obj pos { val x = 3 val y = 4 } val result = pos.x" in
+    let ast = parse "val output = min(4, min(2, 7))" in
     let prog = compile ast in
     let ret = run prog in
     Fmt.pr "{\"program\":%a,\"output\":%a}" Code.pp_program prog Value.pp ret

lib/compile/bcc.ml

@@ -1,6 +1,7 @@
 module Ast = Spice_syntax.Ast
 module Code = Spice_runtime.Code
 module Value = Spice_runtime.Value
+module Interp = Spice_runtime.Interp
 module Env = Map.Make (String)
 
 type binding = {
@@ -142,7 +143,11 @@ let compile modl =
     | Some ret -> ret
   in
 
-  let env = Env.empty in
-  emit_mov 0 (compile_obj env 0 modl.Ast.items);
+  let stdlib_env =
+    List.to_seq Interp.stdlib
+    |> Seq.mapi (fun i (name, _) -> name, { self = 0; elem = Value.Method i })
+    |> Env.of_seq
+  in
+  emit_mov 0 (compile_obj stdlib_env 1 modl.Ast.items);
   emit RET;
   Code.make_program ep

lib/runtime/interp.ml

@@ -75,14 +75,6 @@ type frame = {
   mutable pc : Code.ins list;
 }
 
-let make_frame prog =
-  {
-    regs = Array.make (Code.frame_size prog) Value.Nil;
-    pc = Code.instructions Code.(prog.entrypoint);
-  }
-
-let return_value fr = fr.regs.(0)
-
 let eval fr = function
   | Code.Cst_nil -> Value.Nil
   | Code.Cst_true -> Value.True
@@ -116,15 +108,63 @@ and call mthd self args =
   match mthd with
   | Code.Method pr ->
       if args <> [] then failwith "Interp.call: TODO: method arguments";
-      run_program pr
+      run pr self
   | _ -> Value.call mthd self args
 
-and run fr =
-  match fr.pc with
-  | [] -> return_value fr
-  | is :: rest ->
-      fr.pc <- rest;
-      exec fr is;
-      run fr
+and run prog self =
+  let frame_size = 1 in
+  let frame_size = max frame_size (Code.frame_size prog) in
+  let fr =
+    let regs = Array.make frame_size Value.Nil in
+    let pc = Code.instructions prog.entrypoint in
+    { regs; pc }
+  in
+  let rec run_loop () =
+    match fr.pc with
+    | [] -> ()
+    | ins :: rest ->
+        fr.pc <- rest;
+        exec fr ins;
+        run_loop ()
+  in
+  fr.regs.(0) <- self;
+  run_loop ();
+  fr.regs.(0)
 
-and run_program pr = run (make_frame pr)
+let stdlib =
+  let println vs =
+    let pp ppf vs =
+      List.iteri
+        (fun i v ->
+          if i > 0 then Fmt.pf ppf " ";
+          Value.pp ppf v)
+        vs
+    in
+    Fmt.pr "%a\n" pp vs;
+    Value.Nil
+  in
+  let min = function
+    | [] -> runtime_error "zero arguments to min()"
+    | [ v ] -> v
+    | v :: vs ->
+        List.fold_left
+          (fun v1 v2 ->
+            match Op.lst v1 v2 with
+            | Value.True -> v1
+            | _ -> v2)
+          v
+          vs
+  in
+  let max = function
+    | [] -> runtime_error "zero arguments to max()"
+    | [ v ] -> v
+    | v :: vs ->
+        List.fold_left
+          (fun v1 v2 ->
+            match Op.grt v1 v2 with
+            | Value.True -> v1
+            | _ -> v2)
+          v
+          vs
+  in
+  [ "println", println; "min", min; "max", max ]

lib/runtime/value.ml

@@ -63,9 +63,17 @@ and pp_obj ppf vtable slots =
     vtable.elems;
   Fmt.pf ppf "}"
 
-type mthd += Native_function of (t -> t list -> t)
+type mthd += Native_function of (t list -> t)
 
-let call mthd self args =
+let call mthd _self args =
   match mthd with
-  | Native_function f -> f self args
+  | Native_function f -> f args
   | _ -> raise Not_found
+
+let native_lib fns =
+  let elems = Hashtbl.create (List.length fns * 4) in
+  List.iteri (fun i (name, _) -> Hashtbl.add elems name (Method i)) fns;
+  let mthds = List.map (fun (_, f) -> Native_function f) fns in
+  let mthds = Array.of_list mthds in
+  let vtable = { n_slots = 0; elems; mthds } in
+  Obj (vtable, [||])

lib/spice.ml

@@ -15,5 +15,8 @@ let parse input =
 let compile ast = Spice_compile.Bcc.compile ast
 
 let run prog =
-  try Spice_runtime.Interp.run_program prog
+  try
+    let open Spice_runtime in
+    let stdlib = Value.native_lib Interp.stdlib in
+    Interp.run prog stdlib
   with Spice_runtime.Interp.Runtime_error msg -> failf "runtime error: %s" msg