Allow functions "returning strings" (etc), redefine sort function.

[goals.git] / src / eval.ml

diff --git a/src/eval.ml b/src/eval.ml
index a0ed834..53c4dd0 100644 (file)
--- a/src/eval.ml
+++ b/src/eval.ml
@@ -142,6 +142,33 @@ and expr_to_shell_string env = function
      failwithf "%a: cannot use tactic in shell expansion"
        Ast.string_loc loc
 
+and run_code ?(quiet = false) env loc code =
+  let code = to_shell_script env loc code in
+  let code =
+    "source " ^ Filename.quote Cmdline.prelude_sh_file ^ "\n" ^
+    "set -e\n" ^
+    (if not quiet then "set -x\n" else "") ^
+    "\n" ^
+    code in
+
+  let chan = Unix.open_process_in code in
+  let b = Buffer.create 1024 in
+  (try
+     while true do
+       Buffer.add_string b (input_line chan);
+       Buffer.add_char b '\n'
+     done
+   with End_of_file -> ());
+  let st = Unix.close_process_in chan in
+  let i =
+    match st with
+    | Unix.WEXITED i -> i
+    | Unix.WSIGNALED i ->
+       failwithf "%a: killed by signal %d" Ast.string_loc loc i
+    | Unix.WSTOPPED i ->
+       failwithf "%a: stopped by signal %d" Ast.string_loc loc i in
+  i, Buffer.contents b
+
 and evaluate_goal_arg env = function
   | Ast.EVar (loc, name) ->
      let expr = Ast.getvar env loc name in
@@ -183,16 +210,17 @@ and evaluate_goal_arg env = function
 (* Functions are only called from goal args or when substituting
  * into a shell script or constant expression (this may change if we
  * implement ‘:=’ assignment for variables).  This evaluates a
- * function by running the associated shell script and substituting
- * the output into an EList.
- *
- * XXX In future allow functions to be annotated with a return type.
+ * function by running the associated shell script and parsing
+ * the output as an expression, string or list of strings.
  *)
-and call_function env loc name args (params, code) =
+and call_function env loc name args (params, returning, code) =
   (* This is used to print the function in debug and error messages only. *)
   let debug_func =
-    sprintf "%s (%s)" name
-      (String.concat ", " (List.map (Ast.string_expr ()) args)) in
+    sprintf "%s (%s) returning %s" name
+      (String.concat ", " (List.map (Ast.string_expr ()) args))
+      (match returning with RetExpr -> "expression"
+                          | RetString -> "string"
+                          | RetStrings -> "strings") in
   Cmdline.debug "%a: running function %s" Ast.string_loc loc debug_func;
 
   (* Evaluate function args.  Must be done before updating the environment. *)
@@ -210,27 +238,24 @@ and call_function env loc name args (params, code) =
           (List.length params) (List.length args) in
     List.fold_left (fun env (k, v) -> Ast.Env.add k v env) env params in
 
-  (* Run the code. *)
-  let code = to_shell_script env loc code in
-  let code = "set -e\n" (*^ "set -x\n"*) ^ "\n" ^ code in
-
-  let chan = Unix.open_process_in code in
-  let lines = ref [] in
-  (try while true do lines := input_line chan :: !lines done
-   with End_of_file -> ());
-  let lines = List.rev !lines in
-  let st = Unix.close_process_in chan in
-  (match st with
-  | Unix.WEXITED 0 -> ()
-  | Unix.WEXITED i ->
-     eprintf "*** function ‘%s’ failed with exit code %d\n" name i
-  | Unix.WSIGNALED i ->
-     eprintf "*** function ‘%s’ killed by signal %d\n" name i
-  | Unix.WSTOPPED i ->
-     eprintf "*** function ‘%s’ stopped by signal %d\n" name i
+  let r, b = run_code env loc code in
+  if r <> 0 then (
+    eprintf "*** function ‘%s’ failed with exit code %d\n" name r;
+    exit 1
   );
 
-  Ast.EList (Ast.noloc,
-             (List.map (fun line ->
-                  Ast.EConstant (Ast.noloc, Ast.CString line))
-                lines))
+  match returning with
+  | RetExpr -> Parse.parse_expr (sprintf "function:%s" name) b
+  | RetString -> Ast.EConstant (loc, Ast.CString b)
+  | RetStrings ->
+     (* run_code always adds \n after the final line, so when we
+      * read it back we will get a final empty string which we
+      * have to drop.  XXX Probably better to preserve the lines
+      * read from the external command.
+      *)
+     let strs = nsplit "\n" b in
+     let strs = List.rev strs in
+     let strs = match strs with "" :: xs -> xs | xs -> xs in
+     let strs = List.rev strs in
+     let strs = List.map (fun s -> Ast.EConstant (loc, Ast.CString s)) strs in
+     EList (loc, strs)