Implement 'as' operator.

lib/compiler/implementation/scanner/listener.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.
 
 final bool VERBOSE = false;
 
 /**
  * A parser event listener that does nothing except throw exceptions
  * on parser errors.
  */
@@ skipping 287 matching lines @@
 
   void endVariablesDeclaration(int count, Token endToken) {
   }
 
   void beginWhileStatement(Token token) {
   }
 
   void endWhileStatement(Token whileKeyword, Token endToken) {
   }
 
+  void handleAsOperator(Token operathor, Token endToken) {
+    // TODO(ahe): Rename [operathor] to "operator" when VM bug is fixed.
+  }
+
   void handleAssignmentExpression(Token token) {
   }
 
   void handleBinaryExpression(Token token) {
   }
 
   void handleConditionalExpression(Token question, Token colon) {
   }
 
   void handleConstExpression(Token token, bool named) {
@@ skipping 730 matching lines @@
   }
 
   void beginCascade(Token token) {
     pushNode(new CascadeReceiver(popNode(), token));
   }
 
   void endCascade() {
     pushNode(new Cascade(popNode()));
   }
 
+  void handleAsOperator(Token operathor, Token endToken) {
+    TypeAnnotation type = popNode();
+    Expression expression = popNode();
+    NodeList arguments = new NodeList.singleton(type);
+    pushNode(new Send(expression, new Operator(operathor), arguments));
+  }
+
   void handleAssignmentExpression(Token token) {
     Node arg = popNode();
     Node node = popNode();
     Send send = node.asSend();
     if (send === null) internalError(node: node);
     if (!(send.isPropertyAccess || send.isIndex)) internalError(node: send);
     if (send.asSendSet() !== null) internalError(node: send);
     NodeList arguments;
     if (send.isIndex) {
       Link<Node> link = new Link<Node>(arg);
@@ skipping 461 matching lines @@
 
 Node parse(DiagnosticListener diagnosticListener,
            CompilationUnitElement element,
            doParse(Parser parser)) {
   NodeListener listener = new NodeListener(diagnosticListener, element);
   doParse(new Parser(listener));
   Node node = listener.popNode();
   assert(listener.nodes.isEmpty());
   return node;
 }