ES6: Implement WeakSet

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index c5604ab30f359b1287a664ed22d3656d8843b075..2ea7af1135a4d4eea633e185ec703111747d5a91 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -325,3 +325,94 @@ function SetUpWeakMap() {
 }
 
 SetUpWeakMap();
+
+
+// -------------------------------------------------------------------
+// Harmony WeakSet
+
+var weaksetDataSymbol = %CreateSymbol(void 0);
+
+
+function WeakSet() {
+  if (%_IsConstructCall()) {
+    this[weaksetDataSymbol] = new $WeakMap();
+  } else {
+    return new $WeakSet();
+  }
+}
+
+
+var $WeakSet = WeakSet;
+
+
+function WeakSetAdd(value) {
+  var weaksetData = this[weaksetDataSymbol];
+  if (!weaksetData) {
+    throw %MakeTypeError('incompatible_method_receiver',
+                         ['WeakSet.prototype.add', this]);
+  }
+  if (!(IS_SPEC_OBJECT(value) || IS_SYMBOL(value))) {
+    throw %MakeTypeError('invalid_weakset_value', [this, value]);
+  }
+  return %WeakMapSet(weaksetData, value, true);
+}
+
+
+function WeakSetHas(value) {
+  var weaksetData = this[weaksetDataSymbol];
+  if (!weaksetData) {
+    throw %MakeTypeError('incompatible_method_receiver',
+                         ['WeakSet.prototype.has', this]);
+  }
+  if (!(IS_SPEC_OBJECT(value) || IS_SYMBOL(value))) {
+    throw %MakeTypeError('invalid_weakset_value', [this, value]);
+  }
+  return %WeakMapHas(weaksetData, value);
+}
+
+
+function WeakSetDelete(value) {
+  var weaksetData = this[weaksetDataSymbol];
+  if (!weaksetData) {
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['WeakSet.prototype.delete', this]);
+  }
+  if (!(IS_SPEC_OBJECT(value) || IS_SYMBOL(value))) {
+    throw %MakeTypeError('invalid_weakset_value', [this, value]);
+  }
+  return %WeakMapDelete(weaksetData, value);
+}
+
+
+function WeakSetClear() {
+  if (!this[weaksetDataSymbol]) {
+    throw %MakeTypeError('incompatible_method_receiver',
+                         ['WeakSet.prototype.clear', this]);
+  }
+
+  this[weaksetDataSymbol] = new $WeakMap();
+}
+
+
+// -------------------------------------------------------------------
+
+function SetUpWeakSet() {
+  %CheckIsBootstrapping();
+
+  %SetProperty(global, 'WeakSet', $WeakSet, DONT_ENUM);
+
+  %FunctionSetInstanceClassName($WeakSet, 'WeakSet');
+
+  %FunctionSetPrototype($WeakSet, new $Object());
+  %SetProperty($WeakSet.prototype, 'constructor', $WeakSet, DONT_ENUM);
+
+  // Set up the non-enumerable functions on the WeakSet prototype object.
+  InstallFunctions($WeakSet.prototype, DONT_ENUM, $Array(
+    'add', WeakSetAdd,
+    'has', WeakSetHas,
+    'delete', WeakSetDelete,
+    'clear', WeakSetClear
+  ));
+}
+
+SetUpWeakSet();