public Parser sizePhrase() {
        if (sizePhraseParser == null) {
           FutureParser future = scoped("sizePhrase");
           sizePhraseParser = future;
           future.setParser(
               sequence(
                   token("SIZE"),
                   optional(
                       token("IS")
                   ),
                   choice(
                       identifier(),
                       literal()
                   )
               )
           );
        }

        return sizePhraseParser;
    }