public Parser bitwiseOperator() {
        if (bitwiseOperatorParser == null) {
           FutureParser future = scoped("bitwiseOperator");
           bitwiseOperatorParser = future;
           future.setParser(
               choice(
                   token("B-AND"),
                   token("B-OR"),
                   token("B-XOR"),
                   token("B-EXOR")
               )
           );
        }

        return bitwiseOperatorParser;
    }