Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:78472
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain lsces.co.uk from 217.147.176.214 cause and error)
Message-ID: <54526AE0.7060702@lsces.co.uk>
Date: Thu, 30 Oct 2014 16:44:16 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.0
MIME-Version: 1.0
To: internals@lists.php.net
References: <544DA1CD.9070109@php.net> <CAEbg-4YmUzuAEJZOqqCC=vJ=XY5b7HCZnj25B_JYxu1XJof_YQ@mail.gmail.com> <4ED7146272E04A47B986ED49E771E347BD7E35E061@Ikarus.ameusgmbh.intern> <51CF9ADE-2E04-4BC0-9E5C-B93498251F59@php.net> <5452158A.6070003@lsces.co.uk> <2BB0BBCF-87D2-4E13-9B59-B18A17572B37@gmail.com>
In-Reply-To: <2BB0BBCF-87D2-4E13-9B59-B18A17572B37@gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] [RFC] Using objects as keys
From: lester@lsces.co.uk (Lester Caine)

On 30/10/14 15:06, Rowan Collins wrote:
> On 30 October 2014 10:40:10 GMT, Lester Caine <lester@lsces.co.uk> wrote:
>> On 30/10/14 07:19, Will Fitch wrote:
>>> The magic method is more of a PHP approach while an interface would
>> be more appropriate.  That said, this RFC is a true representation of a
>> hash vs something like spl_object_hash.  That’s what causes user
>> confusion.  spl_object_hash would’ve been better served as a name like
>> spl_object_id or spl_object_hash_id.  Something that indicates
>> uniqueness regardless of the values of a particular object.
>>
>> The bit of the jigsaw I'm still missing here is just what the object of
>> the exercise is?
> 
> 
> There are many different use cases for hash keys, and PHP's "array" type is particularly flexible.
> 
> For instance, de-duplicating a list of items ($foo[$x] = $x), or counting occurrences of each ($foo[$x]++)
> 
> In the case of a simple DB model, the primary key value is the obvious choice for the hash key, but not all objects are as simple as that.
> 
> Being able to store the object itself would save having to recreate it from the key, e.g. looking the ID back up for a DB model, or re-parsing UTF8 for a UString.

But that statement makes no sense!

Accessing the object is via a handle, so you will always have a pointer
to it. Adding some abstract identifier to describe the pointer is always
going to be secondary to the pointer itself? You need a name to create
an object and creating an array of objects needs keys which can either
just be the PHP default location in the array, or you add a name to that
key in some way. The content of the location in the array is the handle
to the object. It will never be 'the object'?

To look up an object you need to know something about the object and
that is either some subset of the object or an abstract reference which
one looks up in order to access the pointer.

-- 
Lester Caine - G8HFL
-----------------------------
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk