public Parser onOverflow() {
        if (onOverflowParser == null) {
           FutureParser future = scoped("onOverflow");
           onOverflowParser = future;
           future.setParser(
               sequence(
                   optional(
                       token("ON")
                   ),
                   token("OVERFLOW"),
                   nestedStatements()
               )
           );
        }

        return onOverflowParser;
    }