anchor.diff:      } catch (FormatException) {
         return element;
       }
  -  }).toList(growable:false);
  +  }).toList(growable: false);
   }
   
   int _compareStrings(String a, String b) {
  
positive.code:   }
    var sorted = [a, b]..sort();
    return identical(sorted[0], a) ? -1 : 1;
  }
negative.code: 
      if (this._index < (this._source.length - 1)) {
        if (this.current == '+') {
          this.consume();
          this.tokenizeBuild();
        } else {
          throw new Exception('bad tag');
        }
      }
  
  