Change getRange to sublist. Make getRange deprecated.

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(length) native "ObjectArray_allocate";
 
@@ skipping 64 matching lines @@
   void removeRange(int start, int length) {
     throw new UnsupportedError(
         "Cannot remove range of a non-extendable array");
   }
 
   void insertRange(int start, int length, [E initialValue = null]) {
     throw new UnsupportedError(
         "Cannot insert range in a non-extendable array");
   }
 
-  List<E> getRange(int start, int length) {
-    if (length == 0) return [];
-    Arrays.rangeCheck(this, start, length);
+
+  List<E> sublist(int start, [int end]) {
+    Arrays.indicesCheck(this, start, end);

[srdjan, 2013/03/18 16:24:41]

It seems that this version of sublist is considerably slower than deleted
getRange for small ranges (7 vs 4 tests). Also remember that using optional
arguments is slow and should not be used in high performance code.

+    if (end == null) end = this.length;
+    int length = end - start;
+    if (start == end) return [];
     List list = new _GrowableObjectArray<E>.withCapacity(length);
     list.length = length;
     Arrays.copy(this, start, list, 0, length);
     return list;
   }
 
+  List<E> getRange(int start, int length) => sublist(start, start + length);
+
   // Iterable interface.
 
   bool contains(E element) {
     return IterableMixinWorkaround.contains(this, element);
   }
 
   void forEach(f(E element)) {
     IterableMixinWorkaround.forEach(this, f);
   }
 
@@ skipping 214 matching lines @@
   void removeRange(int start, int length) {
     throw new UnsupportedError(
         "Cannot remove range of an immutable array");
   }
 
   void insertRange(int start, int length, [E initialValue = null]) {
     throw new UnsupportedError(
         "Cannot insert range in an immutable array");
   }
 
-  List<E> getRange(int start, int length) {
-    if (length == 0) return [];
-    Arrays.rangeCheck(this, start, length);
+  List<E> sublist(int start, [int end]) {
+    Arrays.indicesCheck(this, start, end);
+    if (end == null) end = this.length;
+    int length = end - start;
+    if (start == end) return [];
     List list = new List<E>();
     list.length = length;
     Arrays.copy(this, start, list, 0, length);
     return list;
   }
 
+  List<E> getRange(int start, int length) => sublist(start, start + length);
+
   // Collection interface.
 
   bool contains(E element) {
     return IterableMixinWorkaround.contains(this, element);
   }
 
   void forEach(f(E element)) {
     IterableMixinWorkaround.forEach(this, f);
   }
 
@@ skipping 169 matching lines @@
     }
     _position = _length;
     _current = null;
     return false;
   }
 
   E get current {
     return _current;
   }
 }