Change getRange to sublist. Make getRange deprecated.

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index e4ee5601a9421aa92a44ddd294930c37ddcd321e..1a8977eb6c4c48161109bebc02ae5100a77173b7 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -82,15 +82,20 @@ class _ObjectArray<E> implements List<E> {
         "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) {
@@ -325,15 +330,19 @@ class _ImmutableArray<E> implements List<E> {
         "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) {