anchor.diff:  
   _isDartFile(file) => dartFileRegExp.hasMatch(path.basename(file.path));
   
  -_formatStdin(options) {
  +_formatStdin(kind) {
     var input = new StringBuffer();
     stdin.transform(new Utf8Decoder())
         .listen((data) => input.write(data),
           onError: (error) => _log('Error reading from stdin'),
  -        onDone: () => print(_formatCU(input.toString())));
  +        onDone: () => print(_format(input.toString(), kind)));
   }
   
   /// Initialize the arg parser instance.
  
positive.code:     try {
        var buffer = new StringBuffer();
        var rawSource = file.readAsStringSync();
        var formatted = _formatCU(rawSource);
        if (overwriteFileContents) {
          file.writeAsStringSync(formatted);
        } else {
  
negative.code:   parser.addFlag('write', abbr: 'w', negatable: false,
        help: 'Write reformatted sources to files (overwriting contents).  '
              'Do not print reformatted sources to standard output.');
    parser.addOption('kind', abbr: 'k', defaultsTo: 'cu',
        help: 'Specify source snippet kind ("stmt" or "cu")'
              ' --- [PROVISIONAL API].');
    parser.addFlag('machine', abbr: 'm', negatable: false,
        help: 'Produce output in a format suitable for parsing.');
    parser.addOption('selection', abbr: 's',
  