I have just finished refactoring this code. Please let me know if you still have issues. In the future when you encounter Parse Errors in PHP, it is also helpful if you post your PHP version with the bug report. I believe our development server uses PHP 5.5 currently, so sometimes a dev might use newer syntax that simply does not work on earlier PHP versions.
We try to keep a lookout for this, but sometimes it is not obvious. For example, according to my reading assigning class constants during instantiation should always cause an error, yet the code you reported was able to pass QA when running the upgrader on our dev site.