Big merge from experimental to bleeding edge.

sdk/lib/core/queue.dart

 // Copyright (c) 2011, 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.
 
 part of dart.core;
 
 /**
  * A [Queue] is a collection that can be manipulated at both ends. One
  * can iterate over the elements of a queue through [forEach] or with
  * an [Iterator].
@@ skipping 32 matching lines @@
    * Adds [value] at the end of the queue.
    */
   void addLast(E value);
 
   /**
    * Adds [value] at the end of the queue.
    */
   void add(E value);
 
   /**
-   * Adds all elements of [collection] at the end of the queue. The
-   * length of the queue is extended by the length of [collection].
+   * Adds all elements of [iterable] at the end of the queue. The
+   * length of the queue is extended by the length of [iterable].
    */
-  void addAll(Collection<E> collection);
-
-  /**
-   * Returns the first element of the queue. Throws an
-   * [StateError] exception if this queue is empty.
-   */
-  E get first;
-
-  /**
-   * Returns the last element of the queue. Throws an
-   * [StateError] exception if this queue is empty.
-   */
-  E get last;
+  void addAll(Iterable<E> iterable);
 
   /**
    * Removes all elements in the queue. The size of the queue becomes zero.
    */
   void clear();
 }
 
 
 /**
  * An entry in a doubly linked list. It contains a pointer to the next
@@ skipping 86 matching lines @@
   }
 }
 
 /**
  * Implementation of a double linked list that box list elements into
  * DoubleLinkedQueueEntry objects.
  *
  * WARNING: This class is temporary located in dart:core. It'll be removed
  * at some point in the near future.
  */
-class DoubleLinkedQueue<E> implements Queue<E> {
+class DoubleLinkedQueue<E> extends Iterable<E> implements Queue<E> {
   _DoubleLinkedQueueEntrySentinel<E> _sentinel;
 
   DoubleLinkedQueue() {
     _sentinel = new _DoubleLinkedQueueEntrySentinel<E>();
   }
 
   factory DoubleLinkedQueue.from(Iterable<E> other) {
     Queue<E> list = new DoubleLinkedQueue();
     for (final e in other) {
       list.addLast(e);
     }
     return list;
   }
 
   void addLast(E value) {
     _sentinel.prepend(value);
   }
 
   void addFirst(E value) {
     _sentinel.append(value);
   }
 
   void add(E value) {
     addLast(value);
   }
 
-  void addAll(Collection<E> collection) {
-    for (final e in collection) {
+  void addAll(Iterable<E> iterable) {
+    for (final e in iterable) {
       add(e);
     }
   }
 
   E removeLast() {
     return _sentinel._previous.remove();
   }
 
   E removeFirst() {
     return _sentinel._next.remove();
   }
 
   E get first {
     return _sentinel._next.element;
   }
 
   E get last {
     return _sentinel._previous.element;
   }
 
+  E get single {
+    // Note that this also covers the case where the queue is empty.
+    if (identical(_sentinel._next, _sentinel._previous)) {
+      return _sentinel._next.element;
+    }
+    throw new StateError("More than one element");
+  }
+
   DoubleLinkedQueueEntry<E> lastEntry() {
     return _sentinel.previousEntry();
   }
 
   DoubleLinkedQueueEntry<E> firstEntry() {
     return _sentinel.nextEntry();
   }
 
-  int get length {
-    int counter = 0;
-    forEach((E element) { counter++; });
-    return counter;
-  }
-
   bool get isEmpty {
     return (identical(_sentinel._next, _sentinel));
   }
 
   void clear() {
     _sentinel._next = _sentinel;
     _sentinel._previous = _sentinel;
   }
 
-  void forEach(void f(E element)) {
-    DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (!identical(entry, _sentinel)) {
-      DoubleLinkedQueueEntry<E> nextEntry = entry._next;
-      f(entry._element);
-      entry = nextEntry;
-    }
-  }
-
   void forEachEntry(void f(DoubleLinkedQueueEntry<E> element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
     while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       f(entry);
       entry = nextEntry;
     }
   }
 
-  bool every(bool f(E element)) {
-    DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (!identical(entry, _sentinel)) {
-      DoubleLinkedQueueEntry<E> nextEntry = entry._next;
-      if (!f(entry._element)) return false;
-      entry = nextEntry;
-    }
-    return true;
-  }
-
-  bool some(bool f(E element)) {
-    DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (!identical(entry, _sentinel)) {
-      DoubleLinkedQueueEntry<E> nextEntry = entry._next;
-      if (f(entry._element)) return true;
-      entry = nextEntry;
-    }
-    return false;
-  }
-
-  Queue map(f(E element)) {
-    Queue other = new Queue();
-    DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (!identical(entry, _sentinel)) {
-      DoubleLinkedQueueEntry<E> nextEntry = entry._next;
-      other.addLast(f(entry._element));
-      entry = nextEntry;
-    }
-    return other;
-  }
-
-  dynamic reduce(dynamic initialValue,
-                 dynamic combine(dynamic previousValue, E element)) {
-    return Collections.reduce(this, initialValue, combine);
-  }
-
-  Queue<E> filter(bool f(E element)) {
-    Queue<E> other = new Queue<E>();
-    DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (!identical(entry, _sentinel)) {
-      DoubleLinkedQueueEntry<E> nextEntry = entry._next;
-      if (f(entry._element)) other.addLast(entry._element);
-      entry = nextEntry;
-    }
-    return other;
-  }
-
-  _DoubleLinkedQueueIterator<E> iterator() {
+  _DoubleLinkedQueueIterator<E> get iterator {
     return new _DoubleLinkedQueueIterator<E>(_sentinel);
   }
 
   String toString() {
     return Collections.collectionToString(this);
   }
 }
 
 class _DoubleLinkedQueueIterator<E> implements Iterator<E> {
-  final _DoubleLinkedQueueEntrySentinel<E> _sentinel;
-  DoubleLinkedQueueEntry<E> _currentEntry;
+  _DoubleLinkedQueueEntrySentinel<E> _sentinel;
+  DoubleLinkedQueueEntry<E> _currentEntry = null;
+  E _current;
 
-  _DoubleLinkedQueueIterator(_DoubleLinkedQueueEntrySentinel this._sentinel) {
-    _currentEntry = _sentinel;
+  _DoubleLinkedQueueIterator(_DoubleLinkedQueueEntrySentinel<E> sentinel)
+      : _sentinel = sentinel, _currentEntry = sentinel;
+
+  bool moveNext() {
+    // When [_currentEntry] it is set to [:null:] then it is at the end.
+    if (_currentEntry == null) {
+      assert(_current == null);
+      return false;
+    }
+    _currentEntry = _currentEntry._next;
+    if (identical(_currentEntry, _sentinel)) {
+      _currentEntry = null;
+      _current = null;
+      _sentinel = null;
+      return false;
+    }
+    _current = _currentEntry.element;
+    return true;
   }
 
-  bool get hasNext {
-    return !identical(_currentEntry._next, _sentinel);
-  }
-
-  E next() {
-    if (!hasNext) {
-      throw new StateError("No more elements");
-    }
-    _currentEntry = _currentEntry._next;
-    return _currentEntry.element;
-  }
+  E get current => _current;
 }