anchor.diff:        }
         ++i;
       }
  -    return i - 1;
     }
   }
   
  
positive.code: library rewriter;
  
  class Rewriter {
    List _tokens;
  
    const EXPRESSION_START = const ['{', 'indent'],
      EXPRESSION_END = const ['}', 'outdent'],
  
negative.code:       }
        if (token[0] == 'ident' && (tokens[i + 1][0] == 'space' && tokens[i + 2][0] == 'selector')) {
          token[0] = 'selector';
          token[1] = token[1].concat(' ${tokens[i + 2][1]}');
          tokens.removeRange(i + 1, 2);
        }
        return 1;
      });
    }
  
    void _detectEnd(num i, Condition condition, Action action) {
      var levels = 0;
      while (i < _tokens.length) {
        var token = _tokens[i];
        if (levels == 0 && condition(token, i)) {
          return action(token, i);
        }
        if (levels < 0) {
          return action(token, i);
        }
        if (EXPRESSION_START.indexOf(token[0]) != -1) {
          ++levels;
  