[RFC] Using objects as keys

Hi! I would like to present to your attention an RFC about using object as keys: https://wiki.php.net/rfc/objkey It was discussed in the past on the list: http://marc.info/?t=141145969600001&r=1&w=2 and I think it makes sense to propose a formal RFC for it. Both the text and the code in the patch includes bits done by myself and Joe Watkins. The patch does not cover 100% of cases but should work for most reasonable scenarios, if something is wrong or you have ideas how to make it better please tell. The name __hash is not final, I am open to using __toKey instead or any reasonable alternative, we may also include a couple of options in the vote if that will be a point of disagreement. Thanks, Stas