public Parser linesAtTop() {
        if (linesAtTopParser == null) {
           FutureParser future = scoped("linesAtTop");
           linesAtTopParser = future;
           future.setParser(
               sequence(
                   optional(
                       token("LINES")
                   ),
                   optional(
                       token("AT")
                   ),
                   token("TOP"),
                   choice(
                       dataName(),
                       integer()
                   )
               )
           );
        }

        return linesAtTopParser;
    }