public Parser identifier_format6() {
        if (identifier_format6Parser == null) {
           FutureParser future = scoped("identifier_format6");
           identifier_format6Parser = future;
           future.setParser(
               choice(
                   token("EXCEPTION-OBJECT"),
                   token("NULL"),
                   token("SELF"),
                   sequence(
                       optional(
                           sequence(
                               className(),
                               token("OF")
                           )
                       ),
                       token("SUPER")
                   )
               )
           );
        }

        return identifier_format6Parser;
    }