anchor.diff:  }
   
   /**
  - * A delegate parser continuation-passing-style (CPS).
  + * A delegate parser for continuation-passing-style (CPS).
    */
   class _ContinuationParser extends _DelegateParser {
     final Function _function;
  
positive.code:       _current = null;
        return false;
      }
      _current = _todo.removeLast();
      _done.add(_current);
      _todo.addAll(_current.children.where((each) => !_done.contains(each)));
      return true;
    }
  
negative.code:    * The implementation first creates a copy of each parser reachable in the
     * input grammar; then the resulting grammar is iteratively transfered and
     * all old parsers are replaced with the transformed ones until we end up
     * with a completely new grammar.
     */
    static Parser transform(Parser root, Parser function(Parser parser)) {
      var mapping = new Map();
  