Implement getRange (returning an Iterable).

sdk/lib/collection/collections.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.
 
 part of dart.collection;
 
 /**
  * This class provides default implementations for Iterables (including Lists).
  *
  * Once Dart receives Mixins it will be replaced with mixin classes.
@@ skipping 309 matching lines @@
   static Iterable mapList(List list, f(var element)) {
     return new MappedListIterable(list, f);
   }
 
   static Iterable expand(Iterable iterable, Iterable f(var element)) {
     return new ExpandIterable(iterable, f);
   }
 
   static Iterable takeList(List list, int n) {
     // The generic type is currently lost. It will be fixed with mixins.
-    // This is currently a List as well as an Iterable.
     return new SubListIterable(list, 0, n);
   }
 
   static Iterable takeWhile(Iterable iterable, bool test(var value)) {
     // The generic type is currently lost. It will be fixed with mixins.
     return new TakeWhileIterable(iterable, test);
   }
 
   static Iterable skipList(List list, int n) {
     // The generic type is currently lost. It will be fixed with mixins.
-    // This is currently a List as well as an Iterable.
     return new SubListIterable(list, n, null);
   }
 
   static Iterable skipWhile(Iterable iterable, bool test(var value)) {
     // The generic type is currently lost. It will be fixed with mixins.
     return new SkipWhileIterable(iterable, test);
   }
 
   static Iterable reversedList(List list) {
     return new ReversedListIterable(list);
   }
 
   static void sortList(List list, int compare(a, b)) {
     if (compare == null) compare = Comparable.compare;
     Sort.sort(list, compare);
   }
 
   static int indexOfList(List list, var element, int start) {
     return Arrays.indexOf(list, element, start, list.length);
   }
 
   static int lastIndexOfList(List list, var element, int start) {
     if (start == null) start = list.length - 1;
     return Arrays.lastIndexOf(list, element, start);
   }
 
+  static Iterable getRangeList(List list, int start, int end) {
+    if (start < 0 || start > list.length) {
+      throw new RangeError.range(start, 0, list.length);
+    }
+    if (end < start || end > list.length) {
+      throw new RangeError.range(end, start, list.length);
+    }
+    // The generic type is currently lost. It will be fixed with mixins.
+    return new SubListIterable(list, start, end);
+  }
+
   static void setRangeList(List list, int start, int length,
                            List from, int startFrom) {
     if (length == 0) return;
 
     if (length < 0) throw new ArgumentError(length);
     if (start < 0) throw new RangeError.value(start);
     if (start + length > list.length) {
       throw new RangeError.value(start + length);
     }
 
@@ skipping 56 matching lines @@
  * The source of the elements may be a [List] or any [Iterable] with
  * efficient [Iterable.length] and [Iterable.elementAt].
  */
 class UnmodifiableListView<E> extends UnmodifiableListBase<E> {
   Iterable<E> _source;
   /** Create an unmodifiable list backed by [source]. */
   UnmodifiableListView(Iterable<E> source) : _source = source;
   int get length => _source.length;
   E operator[](int index) => _source.elementAt(index);
 }