public Parser when() {
        if (whenParser == null) {
           FutureParser future = scoped("when");
           whenParser = future;
           future.setParser(
               sequence(
                   plus(
                       sequence(
                           token("WHEN"),
                           object(),
                           star(
                               sequence(
                                   token("ALSO"),
                                   object()
                               )
                           )
                       )
                   ),
                   nestedStatements()
               )
           );
        }

        return whenParser;
    }