Implement Date.

dart/frog/leg/frog_leg.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.
 
 #library('frog_leg');
 
 #import('../../lib/uri/uri.dart');
 #import('../lang.dart', prefix: 'frog');
 #import('elements/elements.dart');
 #import('io/io.dart', prefix: 'io');
@@ skipping 99 matching lines @@
     } else if (element !== null) {
       if (element.position() === null) {
         // Sometimes, the backend fakes up elements that have no
         // position. So we use the enclosing element instead. It is
         // not a good error location, but cancel really is "internal
         // error" or "not implemented yet", so the vicinity is good
         // enough for now.
         element = element.enclosingElement;
         // TODO(ahe): I plan to overhaul this infrastructure anyways.
       }
-      withCurrentElement(element,
-          () => cancel(reason: reason, token: element.position()));
+      if (element !== null) {
+        withCurrentElement(element,
+            () => cancel(reason: reason, token: element.position()));
+      }
+    } else if (currentElement !== null) {
+      cancel(reason, element: currentElement);
+      return;

[kasperl, 2012/02/21 07:23:30]

We usually do not return after a cancel.

     }
     if (throwOnError) {
       throw new AbortLeg(reason);
     }
     super.cancel(reason, node, token, instruction);
   }
 }
 
 class AbortLeg {
   final message;
   AbortLeg(this.message);
   toString() => 'Aborted due to --throw-on-error: $message';
 }