ES6: Adding support for size to Set and Map

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index d36fe18fa00dcd5fdae1210e5f9470c53cbc41f3..f8e3594bb67a8623d8ce63a97f04412710f43a8d 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -88,6 +88,15 @@ function SetDelete(key) {
 }
 
 
+function SetSize() {

[Michael Starzinger, 2012/11/06 09:32:40]

I think "SetGetSize" or "SetSizeGetter" would be a better naming convention for
getters.

[arv (Not doing code reviews), 2012/11/06 16:02:33]

Done.

+  if (!IS_SET(this)) {
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['Set.prototype.size', this]);
+  }
+  return %SetSize(this);
+}
+
+
 function MapConstructor() {
   if (%_IsConstructCall()) {
     %MapInitialize(this);
@@ -145,6 +154,15 @@ function MapDelete(key) {
 }
 
 
+function MapSize() {

[Michael Starzinger, 2012/11/06 09:32:40]

Likewise for "MapGetSize" or "MapSizeGetter".

+  if (!IS_MAP(this)) {
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['Map.prototype.size', this]);
+  }
+  return %MapSize(this);
+}
+
+
 function WeakMapConstructor() {
   if (%_IsConstructCall()) {
     %WeakMapInitialize(this);
@@ -214,7 +232,16 @@ function WeakMapDelete(key) {
   %SetProperty($Set.prototype, "constructor", $Set, DONT_ENUM);
   %SetProperty($Map.prototype, "constructor", $Map, DONT_ENUM);
 
+  function DefineGetter(object, name, fun) {

[Michael Starzinger, 2012/11/06 09:32:40]

Can we move this into v8natives.js near the implementation of InstallFunctions,
so that it can become the bottle-neck for all builtin getters that we install?

[arv (Not doing code reviews), 2012/11/06 16:02:33]

Done.

I also used a lower level abstraction.

+    %FunctionSetName(fun, name);
+    var desc = new PropertyDescriptor();
+    desc.setGet(fun);
+    desc.setConfigurable(true);
+    DefineObjectProperty(object, name, desc, false);
+  }
+
   // Set up the non-enumerable functions on the Set prototype object.
+  DefineGetter($Set.prototype, "size", SetSize);
   InstallFunctions($Set.prototype, DONT_ENUM, $Array(
     "add", SetAdd,
     "has", SetHas,
@@ -222,6 +249,7 @@ function WeakMapDelete(key) {
   ));
 
   // Set up the non-enumerable functions on the Map prototype object.
+  DefineGetter($Map.prototype, "size", MapSize);
   InstallFunctions($Map.prototype, DONT_ENUM, $Array(
     "get", MapGet,
     "set", MapSet,