- Represent strings internally in UTF-16 format, this makes it

lib/compiler/implementation/js_backend/constant_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.
 
 part of js_backend;
 
 class ConstantEmitter implements ConstantVisitor {
   final Compiler compiler;
   final Namer namer;
 
@@ skipping 92 matching lines @@
         buffer.add(r'\r');
       } else if (identical(code, $LS)) {
         // This Unicode line terminator and $PS are invalid in JS string
         // literals.
         buffer.add(r'\u2028');
       } else if (identical(code, $PS)) {
         buffer.add(r'\u2029');
       } else if (identical(code, $BACKSLASH)) {
         buffer.add(r'\\');
       } else {
-        if (code > 0xffff) {
+        if (code >= 0xD800 && code <= 0xDFFF) {

[ahe, 2012/10/28 12:07:02]

I think you should just remove this check. If the invariant now is that
string.iterator returns a sequence UTF-16 code units, then this should just pass
unmodified through to JavaScript.

[siva, 2012/10/31 01:21:26]

I have decided to drop the change and instead created bug
6418 reflecting the issue with two tests that fail when dart2js tests are run
with a VM that represents strings in UTF-16 format.

On 2012/10/28 12:07:02, ahe wrote:

           compiler.reportError(
               diagnosticNode,
               'Unhandled non-BMP character: U+${code.toRadixString(16)}');
         }
         // TODO(lrn): Consider whether all codes above 0x7f really need to
         // be escaped. We build a Dart string here, so it should be a literal
         // stage that converts it to, e.g., UTF-8 for a JS interpreter.
         if (code < 0x20) {
           buffer.add(r'\x');
           if (code < 0x10) buffer.add('0');
@@ skipping 121 matching lines @@
       buffer.add(getJsConstructor(constant.type.element));
       buffer.add("(");
       for (int i = 0; i < constant.fields.length; i++) {
         if (i != 0) buffer.add(", ");
         _visit(constant.fields[i]);
       }
       buffer.add(")");
     }
   }
 }