public Parser qualifier() {
        if (qualifierParser == null) {
           FutureParser future = scoped("qualifier");
           qualifierParser = future;
           future.setParser(
               star(
                   sequence(
                       choice(
                           token("IN"),
                           token("OF")
                       ),
                       dataName()
                   )
               )
           );
        }

        return qualifierParser;
    }