Few tweaks to the generated code to avoid eg parenthesis.

lib/compiler/implementation/js/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.
 
 class Printer implements NodeVisitor {
   final bool shouldCompressOutput = false;
   leg.Compiler compiler;
   var positionElement;
   leg.CodeBuffer outBuffer;
   int indentLevel = 0;
@@ skipping 260 matching lines @@
   visitThrow(Throw node) {
     outIndent("throw ");
     visitNestedExpression(node.expression, EXPRESSION,
                           newInForInit: false, newAtStatementBegin: false);
     outLn(";");
   }
 
   visitTry(Try node) {
     outIndent("try");
     blockBody(node.body, needsSeparation: true, needsNewline: false);
-    spaceOut();
     if (node.catchPart !== null) {
       visit(node.catchPart);
     }
     if (node.finallyPart !== null) {
       spaceOut();
       out("finally");
       blockBody(node.finallyPart, needsSeparation: true, needsNewline: true);
     } else {
       lineOut();
     }
@@ skipping 343 matching lines @@
 
   visitAccess(PropertyAccess access) {
     visitNestedExpression(access.receiver, CALL,
                           newInForInit: inForInit,
                           newAtStatementBegin: atStatementBegin);
     Node selector = access.selector;
     if (selector is LiteralString) {
       LiteralString selectorString = selector;
       String fieldWithQuotes = selectorString.value;
       if (isValidJavaScriptId(fieldWithQuotes)) {
-        if (isDigit(lastCharCode)) out(" ");
+        if (access.receiver is LiteralNumber) out(" ");
         out(".");
         out(fieldWithQuotes.substring(1, fieldWithQuotes.length - 1));
         return;
       }
     }
     out("[");
     visitNestedExpression(selector, EXPRESSION,
                           newInForInit: false, newAtStatementBegin: false);
     out("]");
   }
@@ skipping 91 matching lines @@
   }
 
   visitLiteralExpression(LiteralExpression node) {
     String template = node.template;
     List<Expression> inputs = node.inputs;
 
     List<String> parts = template.split('#');
     if (parts.length != inputs.length + 1) {
       compiler.internalError('Wrong number of arguments for JS: $template');
     }
-    // Save [atStatementBegin] because visiting the parts might change it.
-    bool beginStatement = atStatementBegin;
-    if (!beginStatement) out("(");
+    // Code that uses JS must take care of operator precedences, and
+    // put parenthesis if needed.
     out(parts[0]);
     for (int i = 0; i < inputs.length; i++) {
       visit(inputs[i]);
       out(parts[i + 1]);
     }
-    if (!beginStatement) out(")");
   }
 
   visitLiteralStatement(LiteralStatement node) {
     outLn(node.code);
   }
 }
 
 /**
  * Returns true, if the given node must be wrapped into braces when used
  * as then-statement in an [If] that has an else branch.
@@ skipping 44 matching lines @@
 }
 
 
 leg.CodeBuffer prettyPrint(Node node,
                            leg.Compiler compiler,
                            Dynamic positionElement) {
   Printer printer = new Printer(compiler, positionElement);
   printer.visit(node);
   return printer.outBuffer;
 }