Implement getRange (returning an Iterable).

sdk/lib/collection/list.dart

 // Copyright (c) 2013, 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.collection;
 
 /**
  * Abstract implementation of a list.
  *
  * All operations are defined in terms of `length`, `operator[]`,
@@ skipping 346 matching lines @@
       throw new RangeError.range(end, start, this.length);
     }
     int length = end - start;
     List<E> result = new List<E>()..length = length;
     for (int i = 0; i < length; i++) {
       result[i] = this[start + i];
     }
     return result;
   }
 
-  List<E> getRange(int start, int length) => sublist(start, start + length);
+  Iterable<E> getRange(int start, int end) {
+    if (start < 0 || start > this.length) {
+      throw new RangeError.range(start, 0, this.length);
+    }
+    if (end < start || end > this.length) {
+      throw new RangeError.range(end, start, this.length);
+    }
+    return new SubListIterable(this, start, end);
+  }
 
   void insertRange(int start, int length, [E initialValue]) {
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
     }
     int oldLength = this.length;
     int moveLength = oldLength - start;
     this.length += length;
     if (moveLength > 0) {
       this.setRange(start + length, moveLength, this, start);
@@ skipping 80 matching lines @@
     for (int i = startIndex; i >= 0; i--) {
       if (this[i] == element) {
         return i;
       }
     }
     return -1;
   }
 
   Iterable<E> get reversed => new ReversedListIterable(this);
 }