anchor.diff:  ArgParser _initArgParser() {
     // NOTE: these flags are placeholders only!
     var parser = new ArgParser();
  -  parser.addFlag('write', abbr: 'w', negatable: false,
  +  parser.addFlag(WRITE_FLAG, 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',
  +  parser.addFlag(TRANSFORM_FLAG, abbr: 't', negatable: false,
  +      help: 'Perform code transformations.');
  +  parser.addOption(MAX_LINE_FLAG, abbr: 'l', defaultsTo: '80',
  +      help: 'Wrap lines longer than this length.');
  +  parser.addOption(KIND_FLAG, abbr: 'k', defaultsTo: 'cu',
         help: 'Specify source snippet kind ("stmt" or "cu")'
               ' --- [PROVISIONAL API].', hide: true);
  -  parser.addFlag('machine', abbr: 'm', negatable: false,
  -      help: 'Produce output in a format suitable for parsing.');
  -  parser.addOption('selection', abbr: 's',
  +  parser.addOption(SELECTION_FLAG, abbr: 's',
         help: 'Specify selection information as an offset,length pair '
               '(e.g., -s "0,4").', hide: true);
  -  parser.addFlag('transform', abbr: 't', negatable: true,
  -      help: 'Perform code transformations.');
  -  parser.addFlag('help', abbr: 'h', negatable: false,
  +  parser.addFlag(MACHINE_FLAG, abbr: 'm', negatable: false,
  +      help: 'Produce output in a format suitable for parsing.');
  +  parser.addFlag(HELP_FLAG, abbr: 'h', negatable: false,
         help: 'Print this usage information.');
     return parser;
   }
  
positive.code: }
  
  _readOptions(options) {
    kind = _parseKind(options['kind']);
    machineFormat = options['machine'];
    overwriteFileContents = options['write'];
    selection = _parseSelection(options['selection']);
    formatterSettings =
        new FormatterOptions(codeTransforms: options['transform']);
  }
  
  CodeKind _parseKind(kindOption) {
  
negative.code: Selection selection;
  final List<String> paths = [];
  
  
  const HELP_FLAG = 'help';
  const KIND_FLAG = 'kind';
  const MACHINE_FLAG = 'machine';
  const WRITE_FLAG = 'write';
  const SELECTION_FLAG = 'selection';
  const TRANSFORM_FLAG = 'transform';
  const MAX_LINE_FLAG = 'max_line_length';
  
  
  const FOLLOW_LINKS = false;
  
  
  