public Parser classSpecifier() {
        if (classSpecifierParser == null) {
           FutureParser future = scoped("classSpecifier");
           classSpecifierParser = future;
           future.setParser(
               sequence(
                   token("CLASS"),
                   className(),
                   optional(
                       sequence(
                           token("AS"),
                           literal()
                       )
                   ),
                   optional(
                       sequence(
                           token("EXPANDS"),
                           className(),
                           token("USING"),
                           choice(
                               className(),
                               interfaceName()
                           )
                       )
                   )
               )
           );
        }

        return classSpecifierParser;
    }