implement exports, fixes #141

lib/src/js/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.
 
 part of js_ast;
 
 abstract class NodeVisitor<T> {
   T visitProgram(Program node);
 
   T visitBlock(Block node);
@@ skipping 227 matching lines @@
     var context = new SimpleJavaScriptPrintingContext();
     var opts = new JavaScriptPrintingOptions(allowKeywordsInProperties: true);
     context.buffer.write('js_ast `');
     accept(new Printer(opts, context));
     context.buffer.write('`');
     return context.getText();
   }
 }
 
 class Program extends Node {
+  /// Script tag hash-bang, e.g. `#!/usr/bin/env node`
+  final String scriptTag;
+
+  /// Top-level statements in the program.
   final List<Statement> body;
-  Program(this.body);
+
+  Program(this.body, {this.scriptTag});
 
   accept(NodeVisitor visitor) => visitor.visitProgram(this);
   void visitChildren(NodeVisitor visitor) {
     for (Statement statement in body) statement.accept(visitor);
   }
   Program _clone() => new Program(body);
 }
 
 abstract class Statement extends Node {
   Statement toStatement() => this;
@@ skipping 1269 matching lines @@
   final Expression expression;
 
   CommentExpression(this.comment, this.expression);
 
   int get precedenceLevel => PRIMARY;
   accept(NodeVisitor visitor) => visitor.visitCommentExpression(this);
   CommentExpression _clone() => new CommentExpression(comment, expression);
 
   void visitChildren(NodeVisitor visitor) => expression.accept(visitor);
 }