public Parser returningPhrase() {
        if (returningPhraseParser == null) {
           FutureParser future = scoped("returningPhrase");
           returningPhraseParser = future;
           future.setParser(
               sequence(
                   choice(
                       token("GIVING"),
                       token("RETURNING")
                   ),
                   choice(
                       integer(),
                       sequence(
                           token("ADDRESS"),
                           token("OF"),
                           identifier()
                       )
                   )
               )
           );
        }

        return returningPhraseParser;
    }