anchor.diff:     * Returns a result indicating a parse success.
      */
     Result success(dynamic result, [int position]) {
  -    return new Success(_buffer, position == null ? _position : position, result);
  +    return new Success(buffer, position == null ? this.position : position, result);
     }
   
     /**
      * Returns a result indicating a parse failure.
      */
     Result failure(String message, [int position]) {
  -    return new Failure(_buffer, position == null ? _position : position, message);
  +    return new Failure(buffer, position == null ? this.position : position, message);
     }
   
     /**
  
positive.code:   /**
     * Returns the line:column if the input is a string, otherwise the position.
     */
    String toPositionString() => Token.positionString(_buffer, _position);
  
  }
  
  
negative.code:   dynamic get value => throw new ParserError(this);
  
    @override
    final String message;
  
    @override
    String toString() => 'Failure[${toPositionString()}]: $message';
  
  }
  
  