fixed Promise return in the REPL by using a wrapper object in async s…

…td.evalScript() (github issue #231)

Makefile

@@ -28,7 +28,7 @@ endif
 # Windows cross compilation from Linux
 #CONFIG_WIN32=y
 # use link time optimization (smaller and faster executables but slower build)
-CONFIG_LTO=y
+#CONFIG_LTO=y
 # consider warnings as errors (for development)
 #CONFIG_WERROR=y
 # force 32 bit build for some utilities

doc/quickjs.texi

@@ -379,7 +379,9 @@ optional properties:
   stack frames below the evalScript.
   @item async
   Boolean (default = false). If true, @code{await} is accepted in the
-  script and a promise is returned.
+  script and a promise is returned. The promise is resolved with an
+  object whose @code{value} property holds the value returned by the
+  script.
   @end table
 
 @item loadScript(filename)

quickjs.c

@@ -34182,9 +34182,21 @@ static __exception int js_parse_program(JSParseState *s)
 
     if (!s->is_module) {
         /* return the value of the hidden variable eval_ret_idx  */
-        emit_op(s, OP_get_loc);
-        emit_u16(s, fd->eval_ret_idx);
+        if (fd->func_kind == JS_FUNC_ASYNC) {
+            /* wrap the return value in an object so that promises can
+               be safely returned */
+            emit_op(s, OP_object);
+            emit_op(s, OP_dup);
 
+            emit_op(s, OP_get_loc);
+            emit_u16(s, fd->eval_ret_idx);
+
+            emit_op(s, OP_put_field);
+            emit_atom(s, JS_ATOM_value);
+        } else {
+            emit_op(s, OP_get_loc);
+            emit_u16(s, fd->eval_ret_idx);
+        }
         emit_return(s, TRUE);
     } else {
         emit_return(s, FALSE);

repl.js

@@ -1310,14 +1310,15 @@ import * as os from "os";
                 /* result is a promise */
                 result.then(print_eval_result, print_eval_error);
             } else {
-                print_eval_result(result);
+                print_eval_result({ value: result });
             }
         } catch (error) {
             print_eval_error(error);
         }
     }
 
     function print_eval_result(result) {
+        result = result.value;
         eval_time = os.now() - eval_start_time;
         std.puts(colors[styles.result]);
         print(result);