Separate Dart backend specific logic from basic Unparser.

lib/compiler/implementation/dart_backend/emitter.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.
 
+class EmitterUnparser extends Unparser {
+  final Map<Node, String> renames;
+
+  EmitterUnparser(this.renames);
+
+  visit(Node node) {
+    if (node !== null && renames.containsKey(node)) {
+      sb.add(renames[node]);
+    } else {
+      super.visit(node);
+    }
+  }
+
+  unparseSendReceiver(Send node, [bool spacesNeeded=false]) {
+    // TODO(smok): Remove ugly hack for library preferences.

[Roman, 2012/10/01 14:10:34]

library prefixes?

+    // Check that renamer does not want to omit receiver at all,
+    // in that case we don't need spaces or dot.
+    if (node.receiver !== null && renames[node.receiver] == '') return;
+    super.unparseSendReceiver(node, spacesNeeded);
+  }
+}
+
 String emitCode(
       Compiler compiler,
-      Unparser unparser,
+      Map<Node, String> renames,
       Map<LibraryElement, String> imports,
       Collection<Element> topLevelElements,
       Map<ClassElement, Collection<Element>> classMembers) {
   final sb = new StringBuffer();
+  final unparser = new EmitterUnparser(renames);
   final processedVariableLists = new Set<VariableListElement>();
 
   void outputElement(Element element) {
     if (element is SynthesizedConstructorElement) return;
     if (element.isField()) {
       assert(element is VariableElement);
       // Different VariableElement's may refer to the same VariableListElement.
       // Output this list only once.
       // TODO: only emit used variables.
       VariableElement variableElement = element;
@@ skipping 57 matching lines @@
   for (final element in topLevelElements) {
     if (element is ClassElement) {
       outputClass(element, classMembers[element]);
     } else {
       outputElement(element);
     }
   }
 
   return sb.toString();
 }