public Parser linePhrase() {
        if (linePhraseParser == null) {
           FutureParser future = scoped("linePhrase");
           linePhraseParser = future;
           future.setParser(
               choice(
                   token("LEFTLINE"),
                   token("OVERLINE"),
                   token("UNDERLINE")
               )
           );
        }

        return linePhraseParser;
    }