Create class AST nodes.

dart/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 visitClassNode(ClassNode node);
   R visitExpressionStatement(ExpressionStatement node);
   R visitFor(For node);
   R visitFunctionExpression(FunctionExpression node);
@@ skipping 51 matching lines @@
     }
   }
 
   abstract Token getBeginToken();
 
   abstract Token getEndToken();
 }
 
 class ClassNode extends Node {
   final Identifier name;
+  final TypeAnnotation superclass;
+  final NodeList interfaces;
 
   final Token beginToken;
+  final Token extendsKeyword;
   final Token endToken;
 
-  const ClassNode(this.name, this.beginToken, this.endToken);
+  const ClassNode(this.name, this.superclass, this.interfaces,
+                  this.beginToken, this.extendsKeyword, this.endToken);
 
   accept(Visitor visitor) => visitor.visitClassNode(this);
 
+  bool get isInterface() => beginToken.stringValue === 'interface';
+
+  bool get isClass() => !isInterface;
+
   Token getBeginToken() => beginToken;
 
   Token getEndToken() => endToken;
 }
 
 class Expression extends Node {
   const Expression();
 }
 
 class Statement extends Node {
@@ skipping 338 matching lines @@
 }
 
 /** Representation of modifiers such as static, abstract, final, etc. */
 class Modifiers {
   final Link<Token> modifiers;
   /** Bit pattern to easy check what modifiers are present. */
   final int flags;
 
   const Modifiers([this.modifiers, this.flags = 0]);
 }