public Parser assignToClause() {
        if (assignToClauseParser == null) {
           FutureParser future = scoped("assignToClause");
           assignToClauseParser = future;
           future.setParser(
               sequence(
                   optional(
                       token("TO")
                   ),
                   optional(
                       choice(
                           token("EXTERNAL"),
                           token("DYNAMIC")
                       )
                   ),
                   choice(
                       diskClause(),
                       dataName(),
                       assignmentName()
                   )
               )
           );
        }

        return assignToClauseParser;
    }