Implement super calls.

frog/leg/tree/nodes.dart

 // Copyright (c) 2011, 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.
 
 interface Visitor<R> {
   R visitBlock(Block node);
   R visitBreakStatement(BreakStatement node);
   R visitCatchBlock(CatchBlock node);
   R visitClassNode(ClassNode node);
   R visitConditional(Conditional node);
@@ skipping 202 matching lines @@
   accept(Visitor visitor) => visitor.visitSend(this);
 
   visitChildren(Visitor visitor) {
     if (receiver !== null) receiver.accept(visitor);
     if (selector !== null) selector.accept(visitor);
     if (argumentsNode !== null) argumentsNode.accept(visitor);
   }
 
   int argumentCount() => argumentsNode.length();
 
+  bool get isSuperCall() {
+    return receiver !== null &&
+           receiver.asIdentifier() !== null &&
+           receiver.asIdentifier().isSuper();
+  }
   bool get isOperator() => selector is Operator;
   bool get isPropertyAccess() => argumentsNode === null;
   bool get isFunctionObjectInvocation() => selector === null;
   bool get isPrefix() => argumentsNode is Prefix;
   bool get isPostfix() => argumentsNode is Postfix;
   bool get isIndex() =>
       isOperator && selector.asOperator().source.stringValue === '[]';
 
   Token getBeginToken() {
     return firstBeginToken(receiver, selector);
@@ skipping 416 matching lines @@
 class Identifier extends Expression {
   final Token token;
 
   SourceString get source() => token.value;
 
   Identifier(Token this.token);
   Identifier.synthetic(String name) : token = new StringToken(null, name, null);
 
   bool isThis() => source.stringValue == 'this';
 
+  bool isSuper() => source.stringValue == 'super';
+
   Identifier asIdentifier() => this;
 
   accept(Visitor visitor) => visitor.visitIdentifier(this);
 
   visitChildren(Visitor visitor) {}
 
   Token getBeginToken() => token;
 
   Token getEndToken() => token;
 }
@@ skipping 566 matching lines @@
 
   visitChildren(Visitor visitor) {
     formals.accept(visitor);
     block.accept(visitor);
   }
 
   Token getBeginToken() => catchKeyword;
 
   Token getEndToken() => block.getEndToken();
 }