Add List.first.

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(int length) native "ObjectArray_allocate";
 
@@ skipping 120 matching lines @@
   void set length(int length) {
     throw new UnsupportedError(
         "Cannot change the length of a non-extendable array");
   }
 
   E removeLast() {
     throw new UnsupportedError(
         "Cannot remove in a non-extendable array");
   }
 
+  E get first {
+    return this[0];
+  }
+
   E get last {
     return this[length - 1];
   }
 }
 
 
 // This is essentially the same class as _ObjectArray, but it does not
 // permit any modification of array elements from Dart code. We use
 // this class for arrays constructed from Dart array literals.
 // TODO(hausner): We should consider the trade-offs between two
@@ skipping 127 matching lines @@
   void set length(int length) {
     throw new UnsupportedError(
         "Cannot change the length of an immutable array");
   }
 
   E removeLast() {
     throw new UnsupportedError(
         "Cannot remove in a non-extendable array");
   }
 
+  E get first {
+    return this[0];
+  }
+
   E get last {
     return this[length - 1];
   }
 }
 
 
 // Iterator for arrays with fixed size.
 class _FixedSizeArrayIterator<E> implements Iterator<E> {
   _FixedSizeArrayIterator(List array)
       : _array = array, _length = array.length, _pos = 0 {
     assert(array is _ObjectArray || array is _ImmutableArray);
   }
 
   bool get hasNext {
     return _length > _pos;
   }
 
   E next() {
     if (!hasNext) {
       throw new StateError("No more elements");
     }
     return _array[_pos++];
   }
 
   final List<E> _array;
   final int _length;  // Cache array length for faster access.
   int _pos;
 }