Add YamlMap.addAll.

pkg/yaml/lib/src/yaml_map.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library yaml_map;
 
 import 'deep_equals.dart';
 import 'utils.dart';
 
 /// This class wraps behaves almost identically to the normal Dart Map
 /// implementation, with the following differences:
 ///
 ///  *  It allows null, NaN, boolean, list, and map keys.
 ///  *  It defines `==` structurally. That is, `yamlMap1 == yamlMap2` if they
 ///     have the same contents.
 ///  *  It has a compatible [hashCode] method.
 class YamlMap implements Map {
   final Map _map;
 
   YamlMap() : _map = new Map();
 
   YamlMap.from(Map map) : _map = new Map.from(map);
 
   YamlMap._wrap(this._map);
 
+  void addAll(Map other) {
+    other.forEach((key, value) {
+      this[key] = value;
+    });
+  }
+
   bool containsValue(value) => _map.containsValue(value);
   bool containsKey(key) => _map.containsKey(_wrapKey(key));
   operator [](key) => _map[_wrapKey(key)];
   operator []=(key, value) { _map[_wrapKey(key)] = value; }
   putIfAbsent(key, ifAbsent()) => _map.putIfAbsent(_wrapKey(key), ifAbsent);
   remove(key) => _map.remove(_wrapKey(key));
   void clear() => _map.clear();
   void forEach(void f(key, value)) =>
     _map.forEach((k, v) => f(_unwrapKey(k), v));
   Iterable get keys => _map.keys.map(_unwrapKey);
@@ skipping 36 matching lines @@
   int get hashCode => hashCodeFor(value);
 
   String toString() => value.toString();
 
   /// This is defined as both values being structurally equal.
   bool operator ==(other) {
     if (other is! _WrappedHashKey) return false;
     return deepEquals(this.value, other.value);
   }
 }