Map/Set: Implement constructor parameter handling

src/collection.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
 var $Set = global.Set;
 var $Map = global.Map;
 
 
+// 7.4.1 CheckIterable ( obj )

[arv (Not doing code reviews), 2014/06/18 21:02:05]

This should probably go in v8natives.js once this file is no longer
experimental.

[rossberg, 2014/06/23 14:16:00]

Agreed. Maybe add a TODO to that end?

We could also consider calling it ToIterable or something -- the spec name is
really poorly chosen, and inconsistent with all other conversions. (I already
filed that with one of my chapter bugs.)

[arv (Not doing code reviews), 2014/06/23 15:43:56]

Done.

+function CheckIterable(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 = CheckIterable(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('not_an_object', [next]);
+    }
+    %_CallFunction(this, next.value, adder);
+  }
 }
 
 
 function SetAddJS(key) {
   if (!IS_SET(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Set.prototype.add', this]);
   }
   return %SetAdd(this, key);
 }
@@ skipping 76 matching lines @@
     "forEach", SetForEach
   ));
 }
 
 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('not_an_object', [next]);

[rossberg, 2014/06/23 14:15:59]

We typically give more specific error messages in cases like these, where the
type error is internal to some library function. Perhaps e.g. 'iterator result
... is not an object', or (below) 'iterator value ... is not an entry'.

[arv (Not doing code reviews), 2014/06/23 15:43:56]

Great idea.

Done.

+    }
+    nextItem = next.value;
+    if (!IS_SPEC_OBJECT(nextItem)) {
+      throw MakeTypeError('not_an_object', [nextItem]);
+    }
+    %_CallFunction(this, nextItem[0], nextItem[1], adder);
+  }
 }
 
 
 function MapGetJS(key) {
   if (!IS_MAP(this)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Map.prototype.get', this]);
   }
   return %MapGet(this, key);
 }
@@ skipping 81 matching lines @@
     "get", MapGetJS,
     "set", MapSetJS,
     "has", MapHasJS,
     "delete", MapDeleteJS,
     "clear", MapClearJS,
     "forEach", MapForEach
   ));
 }
 
 SetUpMap();