public Parser promptPhrase() {
        if (promptPhraseParser == null) {
           FutureParser future = scoped("promptPhrase");
           promptPhraseParser = future;
           future.setParser(
               sequence(
                   token("PROMPT"),
                   optional(
                       choice(
                           sequence(
                               token("CHARACTER"),
                               optional(
                                   token("IS")
                               ),
                               identifier()
                           ),
                           sequence(
                               optional(
                                   token("CHARACTER")
                               ),
                               optional(
                                   token("IS")
                               ),
                               literal()
                           )
                       )
                   )
               )
           );
        }

        return promptPhraseParser;
    }