Make 'where' lazy.

runtime/lib/array.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.
 
 
 // TODO(srdjan): Use shared array implementation.
 class _ObjectArray<E> implements List<E> {
 
   factory _ObjectArray(int length) native "ObjectArray_allocate";
 
@@ skipping 55 matching lines @@
   void forEach(f(E element)) {
     Collections.forEach(this, f);
   }
 
   Iterable mappedBy(f(E element)) => new MappedIterable(this, f);
 
   reduce(initialValue, combine(previousValue, E element)) {
     return Collections.reduce(this, initialValue, combine);
   }
 
-  Collection<E> where(bool f(E element)) {
-    return Collections.where(this, new _GrowableObjectArray<E>(), f);

[Anders Johnsen, 2012/11/20 06:32:21]

You could clean up Collections as you go on with this, to make sure we remove
the functions.

[floitsch, 2012/11/28 13:49:38]

I usually remove the functions there.

-  }
+  Iterable<E> where(bool f(E element)) => new FilteredIterable<E>(this, f);

[Lasse Reichstein Nielsen, 2012/11/20 11:44:57]

FilteredIterable => WhereIterable

[floitsch, 2012/11/28 13:49:38]

Done.

 
   bool every(bool f(E element)) {
     return Collections.every(this, f);
   }
 
   bool some(bool f(E element)) {
     return Collections.some(this, f);
   }
 
   bool get isEmpty {
@@ skipping 122 matching lines @@
   void forEach(f(E element)) {
     Collections.forEach(this, f);
   }
 
   Iterable mappedBy(f(E element)) => new MappedIterable(this, f);
 
   reduce(initialValue, combine(previousValue, E element)) {
     return Collections.reduce(this, initialValue, combine);
   }
 
-  Collection<E> where(bool f(E element)) {
-    return Collections.where(this, new _GrowableObjectArray<E>(), f);
-  }
+  Iterable<E> where(bool f(E element)) => new FilteredIterable<E>(this, f);
 
   bool every(bool f(E element)) {
     return Collections.every(this, f);
   }
 
   bool some(bool f(E element)) {
     return Collections.some(this, f);
   }
 
   bool get isEmpty {
@@ skipping 85 matching lines @@
       return _array[_pos];
     }
     // TODO(floitsch): bad error message.
     throw new StateError("No more elements");
   }
 
   final List<E> _array;
   final int _length;  // Cache array length for faster access.
   int _pos;
 }