Implement cascaded calls.

lib/compiler/implementation/tree/nodes.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.
 
 interface Visitor<R> {
   R visitBlock(Block node);
   R visitBreakStatement(BreakStatement node);
+  R visitCascade(Cascade node);
+  R visitCascadeReceiver(CascadeReceiver node);
   R visitCatchBlock(CatchBlock node);
   R visitClassNode(ClassNode node);
   R visitConditional(Conditional node);
   R visitContinueStatement(ContinueStatement node);
   R visitDoWhile(DoWhile node);
   R visitEmptyStatement(EmptyStatement node);
   R visitExpressionStatement(ExpressionStatement node);
   R visitFor(For node);
   R visitForIn(ForIn node);
   R visitFunctionDeclaration(FunctionDeclaration node);
@@ skipping 83 matching lines @@
       return '<<unparse error: ${getObjectDescription()}: ${unparser.sb}>>';
     }
   }
 
   abstract Token getBeginToken();
 
   abstract Token getEndToken();
 
   Block asBlock() => null;
   BreakStatement asBreakStatement() => null;
+  Cascade asCascade() => null;
+  CascadeReceiver asCascadeReceiver() => null;
   CatchBlock asCatchBlock() => null;
   ClassNode asClassNode() => null;
   Conditional asConditional() => null;
   ContinueStatement asContinueStatement() => null;
   DoWhile asDoWhile() => null;
   EmptyStatement asEmptyStatement() => null;
   Expression asExpression() => null;
   ExpressionStatement asExpressionStatement() => null;
   For asFor() => null;
   ForIn asForIn() => null;
@@ skipping 1433 matching lines @@
 
   Token getBeginToken() => tryKeyword;
 
   Token getEndToken() {
     if (finallyBlock !== null) return finallyBlock.getEndToken();
     if (!catchBlocks.isEmpty()) return catchBlocks.getEndToken();
     return tryBlock.getEndToken();
   }
 }
 
+class Cascade extends Node {
+  final Node expression;
+  Cascade(this.expression);
+
+  Cascade asCascade() => this;
+  accept(Visitor visitor) => visitor.visitCascade(this);
+
+  void visitChildren(Visitor visitor) {
+    expression.accept(visitor);
+  }
+
+  Token getBeginToken() => expression.getBeginToken();
+
+  Token getEndToken() => expression.getEndToken();
+}
+
+class CascadeReceiver extends Node {
+  final Node expression;
+  final Token cascadeOperator;
+  CascadeReceiver(this.expression, this.cascadeOperator);
+
+  CascadeReceiver asCascadeReceiver() => this;
+  accept(Visitor visitor) => visitor.visitCascadeReceiver(this);
+
+  void visitChildren(Visitor visitor) {
+    expression.accept(visitor);
+  }
+
+  Token getBeginToken() => expression.getBeginToken();
+
+  Token getEndToken() => expression.getEndToken();
+}
+
 class CatchBlock extends Node {
   final NodeList formals;
   final Block block;
 
   final catchKeyword;
 
   CatchBlock(this.formals, this.block, this.catchKeyword);
 
   CatchBlock asCatchBlock() => this;
 
@@ skipping 66 matching lines @@
  * argument).
  *
  * TODO(ahe): This method is controversial, the team needs to discuss
  * if top-level methods are acceptable and what naming conventions to
  * use.
  */
 initializerDo(Node node, f(Node node)) {
   SendSet send = node.asSendSet();
   if (send !== null) return f(send.arguments.head);
 }