Add Object.isExtensible & Object.preventExtensions...

...and fix the deep implementation of defineOwnProperty
so that they can work (more or less) properly

builtin_object.go

@@ -126,3 +126,21 @@ func builtinObject_create(call FunctionCall) Value {
 
 	return toValue(object)
 }
+
+func builtinObject_isExtensible(call FunctionCall) Value {
+	object := call.Argument(0)
+	if object := object._object(); object != nil {
+		return toValue(object.stash.extensible())
+	}
+	panic(newTypeError())
+}
+
+func builtinObject_preventExtensions(call FunctionCall) Value {
+	object := call.Argument(0)
+	if object := object._object(); object != nil {
+		object.stash.lock()
+	} else {
+		panic(newTypeError())
+	}
+	return object
+}

global.go

@@ -175,6 +175,8 @@ func newContext() *_runtime {
 		"defineProperty", 3, builtinObject_defineProperty,
 		"defineProperties", 2, builtinObject_defineProperties,
 		"create", 2, builtinObject_create,
+		"isExtensible", -1, builtinObject_isExtensible,
+		"preventExtensions", -1, builtinObject_preventExtensions,
 	)
 
 	self.Global.Function = self.newGlobalFunction(
@@ -669,7 +671,7 @@ func newContext() *_runtime {
 		"RegExp", builtinRegExp,
 		builtinNewRegExp,
 		self.Global.RegExpPrototype,
-		"toString", -0xff, builtinRegExp_toString,
+		"toString", -255, builtinRegExp_toString,
 		"exec", -1, builtinRegExp_exec,
 		"test", -1, builtinRegExp_test,
 	)
@@ -832,7 +834,7 @@ func (runtime *_runtime) newNativeFunction(_nativeFunction _nativeFunction, leng
 	if 0 > length {
 		length *= -1
 		// TODO Achk... hack
-		if length == 0xff {
+		if length == 255 {
 			length = 0
 		}
 		prototype = false

object.go

@@ -196,7 +196,7 @@ func (self *_object) defineOwnProperty(name string, descriptor _property, throw
 	{
 		if !exists {
 			if !self.extensible() {
-				return false
+				goto Reject
 			}
 			self.stash.defineProperty(name, descriptor.value, descriptor.mode)
 			return true
@@ -213,7 +213,7 @@ func (self *_object) defineOwnProperty(name string, descriptor _property, throw
 		configurable := property.configurable()
 		if !configurable {
 			if descriptor.configurable() {
-				return false
+				goto Reject
 			}
 			// Test that, if enumerable is set on the property descriptor, then it should
 			// be the same as the existing property
@@ -237,22 +237,27 @@ func (self *_object) defineOwnProperty(name string, descriptor _property, throw
 		} else if isDataDescriptor && descriptor.isDataDescriptor() {
 			if !configurable {
 				if property.writable() != descriptor.writable() {
-					return false
+					goto Reject
 				} else if !sameValue(value, descriptor.value.(Value)) {
-					return false
+					goto Reject
 				}
 			}
 		} else {
 			if !configurable {
 				defineGetSet, _ := descriptor.value.(_propertyGetSet)
 				if getSet[0] != defineGetSet[0] || getSet[1] != defineGetSet[1] {
-					return false
+					goto Reject
 				}
 			}
 		}
 		self.stash.defineProperty(name, descriptor.value, descriptor.mode)
 		return true
 	}
+Reject:
+	if throw {
+		panic(newTypeError())
+	}
+	return false
 }
 
 func (self *_object) hasOwnProperty(name string) bool {

object_test.go

@@ -62,3 +62,49 @@ func TestObject_toLocaleString(t *testing.T) {
         object.toLocaleString();
     `, "Nothing happens.")
 }
+
+func TestObject_isExtensible(t *testing.T) {
+	Terst(t)
+
+	test := runTest()
+	test(`raise:
+        Object.isExtensible();
+    `, "TypeError")
+	test(`raise:
+        Object.isExtensible({});
+    `, "true")
+
+	test(`Object.isExtensible.length`, "1")
+	test(`Object.isExtensible.prototype`, "undefined")
+}
+
+func TestObject_preventExtensions(t *testing.T) {
+	Terst(t)
+
+	test := runTest()
+	test(`raise:
+        Object.preventExtensions()
+    `, "TypeError")
+
+	test(`raise:
+        var abc = { def: true };
+        var ghi = Object.preventExtensions(abc);
+        [ ghi.def === true, Object.isExtensible(abc), Object.isExtensible(ghi) ];
+    `, "true,false,false")
+
+	test(`
+        var abc = new String();
+        var def = Object.isExtensible(abc);
+        Object.preventExtensions(abc);
+        var ghi = false;
+        try {
+            Object.defineProperty(abc, "0", { value: "~" });
+        } catch (err) {
+            ghi = err instanceof TypeError;
+        }
+        [ def, ghi, abc.hasOwnProperty("0"), typeof abc[0] ];
+    `, "true,true,false,undefined")
+
+	test(`Object.preventExtensions.length`, "1")
+	test(`Object.preventExtensions.prototype`, "undefined")
+}