anchor.diff:      try {
         var buffer = new StringBuffer();
         var rawSource = file.readAsStringSync();
  -      var formatted = _formatCU(rawSource);
  +      var formatted = _format(rawSource, CodeKind.COMPILATION_UNIT);
         if (overwriteFileContents) {
           file.writeAsStringSync(formatted);
         } else {
  
positive.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.addFlag('machine', abbr: 'm', negatable: false,
        help: 'Produce output in a format suitable for parsing.');
    parser.addOption('selection', abbr: 's',
  
negative.code:   _log(buffer.toString());
  }
  
  /// Format this [src], treating it as the given snippet [kind].
  String _format(src, kind) {
    var formatResult = new CodeFormatter(formatterSettings).format(
        kind, src, selection: selection);
    if (machineFormat) {
      if (formatResult.selection == null) {
        formatResult.selection = defaultSelection;
  