anchor.diff:    int _parseTrue(int position) {
       assert(_source.codeUnitAt(position) == CHAR_t);
       if (_source.length < position + 4) _fail(position, "Unexpected identifier");
  -    if (_source.codeUnitAt(position + 1) != CHAR_r || _source.codeUnitAt(position + 2) != CHAR_u || _source.codeUnitAt(position + 3) != CHAR_e) {
  +    if (_source.codeUnitAt(position + 1) != CHAR_r ||
  +        _source.codeUnitAt(position + 2) != CHAR_u ||
  +        _source.codeUnitAt(position + 3) != CHAR_e) {
         _fail(position);
       }
       _listener.handleBool(new Span(position, position + 4), true);
  
positive.code:   int _parseFalse(int position) {
      assert(_source.codeUnitAt(position) == CHAR_f);
      if (_source.length < position + 5) _fail(position, "Unexpected identifier");
      if (_source.codeUnitAt(position + 1) != CHAR_a || _source.codeUnitAt(position + 2) != CHAR_l || _source.codeUnitAt(position + 3) != CHAR_s || _source.codeUnitAt(position + 4) != CHAR_e) {
        _fail(position);
      }
      _listener.handleBool(new Span(position, position + 4), false);
  
negative.code:       }
        char = _source.codeUnitAt(position);
        if (char == QUOTE) {
          _listener.handleString(
              new Span(start - 1, position + 1),
              _source.substring(start, position));
          return position + 1;
        }
        if (char < SPACE) {
  