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Subject: Re: [PHP-DEV] [RFC][VOTE] Objects as Keys
From: rowan.collins@gmail.com (Rowan Collins)

guilhermeblanco@gmail.com wrote on 17/12/2014 12:43:
> Answering the question of Christopher Becker. It is not possible to
> traverse and get your desired elements.
> How would you achieve a foreach by key (returning object) without having to
> store a separate list and track by hash or through an interface?

SplObjectStorage supports that mechanism, although it's not the most 
intuitive design. See this comment in the manual: 
http://php.net/manual/en/class.splobjectstorage.php#114059

As others have pointed out, this proposal does *not* support that usage, 
because the hash function is one-way, and you cannot get back the object 
based only on the calculated key. All it does is reduce the boilerplate 
needed for hashing an object to produce a suitable array key.