Add List.shuffle().

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 283 matching lines @@
   }
 
   void sort([int compare(E a, E b)]) {
     if (compare == null) {
       var defaultCompare = Comparable.compare;
       compare = defaultCompare;
     }
     Sort.sort(this, compare);
   }
 
+  void shuffle() {
+    Random random = new Random();

[rakudrama, 2013/09/26 13:33:25]

This needs to be an optional parameter to assist in the generation of
deterministic but arbitrary state, e.g. you should not use shuffle in the
generation of a benchmark input unless you can arrange all platforms do the same
shuffle.

[floitsch, 2013/09/26 14:25:22]

I don't think that the additional parameter is worth it. If you can pass in your
own Random source, you are advanced enough to simply shuffle the list yourself.
This makes the benchmark robust against changes in the shuffle function itself.

+    int length = this.length;
+    while (--length > 0) {
+      int pos = random.nextInt(length);
+      var tmp = this[length]
+      this[length] = this[pos];
+      list[pos] = tmp;
+    }
+  }
+
   Map<int, E> asMap() {
     return new ListMapView(this);
   }
 
   void _rangeCheck(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);
@@ skipping 172 matching lines @@
       result.writeAll(this, ', ');
       result.write(']');
      } finally {
        assert(identical(_toStringList.last, this));
        _toStringList.removeLast();
      }
 
     return result.toString();
   }
 }