ES6: Implement WeakMap and WeakSet constructor logic

src/v8natives.js

Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index 8484150248a13a2ef01467da31603fab1db88b0c..c1fed948d3a8f61037867b8a3fc5cb3f944ba134 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -1875,3 +1875,33 @@ function SetUpFunction() {
 }
 
 SetUpFunction();
+
+
+// ----------------------------------------------------------------------------
+// Iterator related spec functions.
+
+// ES6 rev 26, 2014-07-18
+// 7.4.1 CheckIterable ( obj )
+function ToIterable(obj) {
+  if (!IS_SPEC_OBJECT(obj)) {
+    return UNDEFINED;
+  }
+  return obj[symbolIterator];
+}
+
+
+// ES6 rev 26, 2014-07-18
+// 7.4.2 GetIterator ( obj, method )
+function GetIterator(obj, method) {
+  if (IS_UNDEFINED(method)) {
+    method = ToIterable(obj);
+  }
+  if (!IS_SPEC_FUNCTION(method)) {
+    throw MakeTypeError('not_iterable', [obj]);
+  }
+  var iterator = %_CallFunction(obj, method);
+  if (!IS_SPEC_OBJECT(iterator)) {
+    throw MakeTypeError('not_an_iterator', [iterator]);
+  }
+  return iterator;
+}