Map/Set: Implement constructor parameter handling

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index 0d8dd77f7bd3be944ffcd25b51544d8ebe740c00..375fdf50190e04e25ef3d47f2bebd3682476481b 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -12,15 +12,64 @@ var $Set = global.Set;
 var $Map = global.Map;
 
 
+// TODO(arv): Move these general functions to v8natives.js when Map and Set are
+// no longer experimental.
+
+
+// 7.4.1 CheckIterable ( obj )
+function ToIterable(obj) {
+  if (!IS_SPEC_OBJECT(obj)) {
+    return UNDEFINED;
+  }
+  return obj[symbolIterator];
+}
+
+
+// 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;
+}
+
+
 // -------------------------------------------------------------------
 // Harmony Set
 
-function SetConstructor() {
-  if (%_IsConstructCall()) {
-    %SetInitialize(this);
-  } else {
+function SetConstructor(iterable) {
+  if (!%_IsConstructCall()) {
     throw MakeTypeError('constructor_not_function', ['Set']);
   }
+
+  var iter, adder;
+
+  if (!IS_NULL_OR_UNDEFINED(iterable)) {
+    iter = GetIterator(iterable);
+    adder = this.add;
+    if (!IS_SPEC_FUNCTION(adder)) {
+      throw MakeTypeError('property_not_function', ['add', this]);
+    }
+  }
+
+  %SetInitialize(this);
+
+  if (IS_UNDEFINED(iter)) return;
+
+  var next, done;
+  while (!(next = iter.next()).done) {
+    if (!IS_SPEC_OBJECT(next)) {
+      throw MakeTypeError('iterator_result_not_an_object', [next]);
+    }
+    %_CallFunction(this, next.value, adder);
+  }
 }
 
 
@@ -117,12 +166,36 @@ SetUpSet();
 // -------------------------------------------------------------------
 // Harmony Map
 
-function MapConstructor() {
-  if (%_IsConstructCall()) {
-    %MapInitialize(this);
-  } else {
+function MapConstructor(iterable) {
+  if (!%_IsConstructCall()) {
     throw MakeTypeError('constructor_not_function', ['Map']);
   }
+
+  var iter, adder;
+
+  if (!IS_NULL_OR_UNDEFINED(iterable)) {
+    iter = GetIterator(iterable);
+    adder = this.set;
+    if (!IS_SPEC_FUNCTION(adder)) {
+      throw MakeTypeError('property_not_function', ['set', this]);
+    }
+  }
+
+  %MapInitialize(this);
+
+  if (IS_UNDEFINED(iter)) return;
+
+  var next, done, nextItem;
+  while (!(next = iter.next()).done) {
+    if (!IS_SPEC_OBJECT(next)) {
+      throw MakeTypeError('iterator_result_not_an_object', [next]);
+    }
+    nextItem = next.value;
+    if (!IS_SPEC_OBJECT(nextItem)) {
+      throw MakeTypeError('iterator_value_not_an_object', [nextItem]);
+    }
+    %_CallFunction(this, nextItem[0], nextItem[1], adder);
+  }
 }