Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:78363
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.192.174 as permitted sender)
Message-ID: <544DB15E.7090704@php.net>
Date: Sun, 26 Oct 2014 19:43:42 -0700
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:31.0) Gecko/20100101 Thunderbird/31.2.0
MIME-Version: 1.0
To: Will Fitch <will@fitch.so>
CC: PHP Internals <internals@lists.php.net>
References: <544DA1CD.9070109@php.net> <A7DB3F27-0306-4401-919A-006000A5C164@fitch.so>
In-Reply-To: <A7DB3F27-0306-4401-919A-006000A5C164@fitch.so>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] [RFC] Using objects as keys
From: smalyshev@gmail.com (Stas Malyshev)

Hi!

> I’m trying to wrap my head around a real-world use-case with this.
> We have spl_object_hash, which effectively provides a unique hash for

This hash has nothing to do with object's contents. But imagine number
GMP("42") and imagine you actually want two GMP objects expressing "42"
actually represent the same hash key. Or imagine you want to generate
the key somehow in a way related to object's content and not just a
random number. As I said in the RFC, evidence that so many languages
implement it shows that this use case is quite real. Of course, you can
always default to spl_object_hash, but now you have control over it.

> an object. If the intent is to provide an opportunity of individual
> classes to decide what their hash is, couldn’t they provide that via
> __toString? I know many frameworks use __toString to build out some
> implementation of an object (Zend form for example), but the point of
> __toString is to provide a string representation of an object.

This is covered in the RFC, right in the introduction.
-- 
Stanislav Malyshev, Software Architect
SugarCRM: http://www.sugarcrm.com/