anchor.diff:      }
       return LINEFEED_PARSER;
     }
  -}
  -
  -/** Non local return. */
  -class NonLocalReturn<T> implements Exception {
  -  final T _value;
  -  NonLocalReturn(this._value);
  -  T get value() => _value;
   }
positive.code:   final int _start;
    final int _stop;
  
    Token(this._buffer, this._start, this._stop);
  
    bool operator == (Token other) => other is Token
        && _buffer === other._buffer
  
negative.code:  */
  class ActionParser extends DelegateParser {
  
    final Action _function;
  
    ActionParser(parser, this._function) : super(parser);
  
  