Execute input in the REPL.

Guesses whether the input is an expression or statement and handles it
appropriately. Finally, after over a year, the Wren REPL automatically
prints "3" if you type in "1 + 2". \o/

src/optional/wren_opt_meta.c

@@ -15,8 +15,12 @@ void metaCompile(WrenVM* vm)
   ObjClosure* caller = vm->fiber->frames[vm->fiber->numFrames - 2].closure;
   ObjModule* module = caller->fn->module;
 
+  const char* source = wrenGetSlotString(vm, 1);
+  bool isExpression = wrenGetSlotBool(vm, 2);
+  bool printErrors = wrenGetSlotBool(vm, 3);
+  
   // Compile it.
-  ObjFn* fn = wrenCompile(vm, module, wrenGetSlotString(vm, 1), false);
+  ObjFn* fn = wrenCompile(vm, module, source, isExpression, printErrors);
 
   // Return the result. We can't use the public API for this since we have a
   // bare ObjFn.
@@ -45,7 +49,7 @@ WrenForeignMethodFn wrenMetaBindForeignMethod(WrenVM* vm,
   // There is only one foreign method in the meta module.
   ASSERT(strcmp(className, "Meta") == 0, "Should be in Meta class.");
   ASSERT(isStatic, "Should be static.");
-  ASSERT(strcmp(signature, "compile_(_)") == 0, "Should be compile method.");
+  ASSERT(strcmp(signature, "compile_(_,_,_)") == 0, "Should be compile method.");
   
   return metaCompile;
 }

src/optional/wren_opt_meta.wren

@@ -2,12 +2,17 @@ class Meta {
   static eval(source) {
     if (!(source is String)) Fiber.abort("Source code must be a string.")
 
-    var fn = compile_(source)
+    var fn = compile_(source, false, false)
     // TODO: Include compile errors.
     if (fn == null) Fiber.abort("Could not compile source code.")
 
     Fiber.new(fn).call()
   }
 
-  foreign static compile_(source)
+  static compileExpression(source) {
+    if (!(source is String)) Fiber.abort("Source code must be a string.")
+    return compile_(source, true, true)
+  }
+
+  foreign static compile_(source, isExpression, printErrors)
 }

src/optional/wren_opt_meta.wren.inc

@@ -4,12 +4,17 @@ static const char* metaModuleSource =
 "  static eval(source) {\n"
 "    if (!(source is String)) Fiber.abort(\"Source code must be a string.\")\n"
 "\n"
-"    var fn = compile_(source)\n"
+"    var fn = compile_(source, false, false)\n"
 "    // TODO: Include compile errors.\n"
 "    if (fn == null) Fiber.abort(\"Could not compile source code.\")\n"
 "\n"
 "    Fiber.new(fn).call()\n"
 "  }\n"
 "\n"
-"  foreign static compile_(source)\n"
+"  static compileExpression(source) {\n"
+"    if (!(source is String)) Fiber.abort(\"Source code must be a string.\")\n"
+"    return compile_(source, true, true)\n"
+"  }\n"
+"\n"
+"  foreign static compile_(source, isExpression, printErrors)\n"
 "}\n";