dart2js: Use an abstract Name class for names in the generated JavaScript ast.

pkg/js_ast/lib/src/printer.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;
 
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
@@ skipping 909 matching lines @@
     Node selector = access.selector;
     if (selector is LiteralString) {
       LiteralString selectorString = selector;
       String fieldWithQuotes = selectorString.value;
       if (isValidJavaScriptId(fieldWithQuotes)) {
         if (access.receiver is LiteralNumber) out(" ", isWhitespace: true);
         out(".");
         out(fieldWithQuotes.substring(1, fieldWithQuotes.length - 1));
         return;
       }
+    } else if (selector is Name) {
+      if (access.receiver is LiteralNumber) out(" ", isWhitespace: true);
+      out(".");
+      out(selector.name);
+      return;
     }
     out("[");
     visitNestedExpression(selector, EXPRESSION,
                           newInForInit: false, newAtStatementBegin: false);
     out("]");
   }
 
   @override
   void visitNamedFunction(NamedFunction namedFunction) {
     VarCollector vars = new VarCollector();
@@ skipping 45 matching lines @@
   void visitLiteralString(LiteralString node) {
     out(node.value);
   }
 
   @override
   visitStringConcatenation(StringConcatenation node) {
     node.visitChildren(this);
   }
 
   @override
+  visitName(Name node) {
+    out(node.name);
+  }
+
+  @override
   visitLiteralNumber(LiteralNumber node) {
     outputNumberWithRequiredWhitespace(node.value);
   }
 
   @override
   void visitLiteralNull(LiteralNull node) {
     out("null");
   }
 
   @override
@@ skipping 55 matching lines @@
   @override
   void visitProperty(Property node) {
     if (node.name is LiteralString) {
       LiteralString nameString = node.name;
       String name = nameString.value;
       if (isValidJavaScriptId(name)) {
         out(name.substring(1, name.length - 1));
       } else {
         out(name);
       }
+    } else if (node.name is Name) {
+      node.name.accept(this);
     } else {
       assert(node.name is LiteralNumber);
       LiteralNumber nameNumber = node.name;
       out(nameNumber.value);
     }
     out(":");
     spaceOut();
     visitNestedExpression(node.value, ASSIGNMENT,
                           newInForInit: false, newAtStatementBegin: false);
   }
@@ skipping 370 matching lines @@
     }
   }
 
   EnterExitNode exitNode(JavaScriptPrintingContext context, int position) {
     // Enter must happen before exit.
     addToNode(context, position);
     context.exitNode(node, startPosition, position, closingPosition);
     return parent;
   }
 }