Parse parenthesized expressions.

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 visitDoWhile(DoWhile node);
   R visitExpressionStatement(ExpressionStatement node);
   R visitFor(For node);
   R visitFunctionExpression(FunctionExpression node);
   R visitIdentifier(Identifier node);
   R visitIf(If node);
   R visitLiteralBool(LiteralBool node);
   R visitLiteralDouble(LiteralDouble node);
   R visitLiteralInt(LiteralInt node);
   R visitLiteralNull(LiteralNull node);
   R visitLiteralString(LiteralString node);
   R visitNodeList(NodeList node);
   R visitOperator(Operator node);
+  R visitParenthesizedExpression(ParenthesizedExpression node);
   R visitReturn(Return node);
   R visitSend(Send node);
   R visitSendSet(SendSet node);
   R visitThrow(Throw node);
   R visitTypeAnnotation(TypeAnnotation node);
   R visitVariableDefinitions(VariableDefinitions node);
   R visitWhile(While node);
 }
 
 Token firstBeginToken(Node first, Node second) {
@@ skipping 47 matching lines @@
   FunctionExpression asFunctionExpression() => this;
   Identifier asIdentifier() => this;
   If asIf() => this;
   LiteralBool asLiteralBool() => this;
   LiteralDouble asLiteralDouble() => this;
   LiteralInt asLiteralInt() => this;
   LiteralNull asLiteralNull() => this;
   LiteralString asLiteralString() => this;
   NodeList asNodeList() => this;
   Operator asOperator() => this;
+  ParenthesizedExpression asParenthesizedExpression() => this;
   Return asReturn() => this;
   Send asSend() => this;
   SendSet asSendSet() => this;
   Throw asThrow() => this;
   TypeAnnotation asTypeAnnotation() => this;
   VariableDefinitions asVariableDefinitions() => this;
   While asWhile() => this;
 }
 
 class ClassNode extends Node {
@@ skipping 161 matching lines @@
   Block(this.statements);
 
   accept(Visitor visitor) => visitor.visitBlock(this);
 
   Token getBeginToken() => statements.getBeginToken();
 
   Token getEndToken() => statements.getEndToken();
 }
 
 class If extends Statement {
-  final NodeList condition;
+  final ParenthesizedExpression condition;
   final Statement thenPart;
   final Statement elsePart;
 
   final Token ifToken;
   final Token elseToken;
 
   If(this.condition, this.thenPart, this.elsePart,
      this.ifToken, this.elseToken);
 
   bool get hasElsePart() => elsePart !== null;
@@ skipping 252 matching lines @@
   While(Expression this.condition, Statement body,
         Token this.whileKeyword) : super(body);
 
   accept(Visitor visitor) => visitor.visitWhile(this);
 
   Token getBeginToken() => whileKeyword;
 
   Token getEndToken() => body.getEndToken();
 }
 
+class ParenthesizedExpression extends Expression {
+  final Expression expression;
+  final BeginGroupToken beginToken;
+
+  ParenthesizedExpression(Expression this.expression,
+                          BeginGroupToken this.beginToken);
+
+  accept(Visitor visitor) => visitor.visitParenthesizedExpression(this);
+
+  Token getBeginToken() => beginToken;
+
+  Token getEndToken() => beginToken.endGroup;
+}
+
 /** 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]);
 }