Rework Unparser/unparse StringBuffer management.

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 visitCaseMatch(CaseMatch node);
@@ skipping 81 matching lines @@
 
   hashCode() => _hashCode;
 
   abstract accept(Visitor visitor);
 
   abstract visitChildren(Visitor visitor);
 
   /**
    * Returns this node unparsed to Dart source string.
    */
-  toString() => unparse();
+  toString() => unparse(this);
 
   /**
    * Returns Xml-like tree representation of this node.
    */
   toDebugString() {
     return PrettyPrinter.prettyPrint(this);
   }
 
   String getObjectDescription() => super.toString();
 
-  String unparse() {
-    Unparser unparser = new Unparser();
-    try {
-      return unparser.unparse(this);
-    } catch (e, trace) {
-      print(trace);
-      return '<<unparse error: ${getObjectDescription()}: ${unparser.sb}>>';
-    }
-  }
-
   abstract Token getBeginToken();
 
   abstract Token getEndToken();
 
   Block asBlock() => null;
   BreakStatement asBreakStatement() => null;
   Cascade asCascade() => null;
   CascadeReceiver asCascadeReceiver() => null;
   CaseMatch asCaseMatch() => null;
   CatchBlock asCatchBlock() => null;
@@ skipping 1628 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);
 }