public Parser dtAtPositioning() {
        if (dtAtPositioningParser == null) {
           FutureParser future = scoped("dtAtPositioning");
           dtAtPositioningParser = future;
           future.setParser(
               sequence(
                   token("AT"),
                   choice(
                       identifier(),
                       literal()
                   )
               )
           );
        }

        return dtAtPositioningParser;
    }