Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:78483
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain fastmail.fm designates 66.111.4.27 as permitted sender)
Content-Type: text/plain;
	charset=us-ascii
Mime-Version: 1.0 (1.0)
In-Reply-To: <54528445.8080604@sugarcrm.com>
Date: Thu, 30 Oct 2014 14:51:49 -0500
Cc: Larry Garfield <larry@garfieldtech.com>,
 "internals@lists.php.net" <internals@lists.php.net>
Content-Transfer-Encoding: quoted-printable
Message-ID: <69356D8D-44FB-411F-907D-94B61D4A472A@fastmail.fm>
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> <54527E7E.2020505@garfieldtech.com> <54528445.8080604@sugarcrm.com>
To: Stas Malyshev <smalyshev@sugarcrm.com>
Subject: Re: [PHP-DEV] [RFC] Using objects as keys
From: willfitch@fastmail.fm (Will Fitch)



> On Oct 30, 2014, at 1:32 PM, Stas Malyshev <smalyshev@sugarcrm.com> wrote:=

>=20
> Hi!
>=20
>> Put another way, I think a key question here is:
>>=20
>> class Foo {
>>   public $bar;
>> }
>>=20
>> $a =3D new Foo;
>> $a->bar =3D 'baz';
>> $b =3D new Foo;
>> $b->bar =3D 'baz';
>>=20
>> $arr[$a] =3D true;
>> $arr[$b] =3D true;
>>=20
>>=20
>> Does $arr now contain one value or two?
>=20
> That depends on the semantics of class Foo. If Foo is something like
> UString, then it should contain one value, since UString is a value
> object (https://en.wikipedia.org/wiki/Value_object) - or at least it
> should be. However, if Foo represents something having separate identity
> - i.e. it's a Person class and 'bar' represents name - then of course it
> should contain two values, since the name is not the sole source of
> Person's identity. So the decision is on you as a programmer.
>=20
> And to give you the tool to make this decision and let PHP engine know
> about is exactly the point of this RFC.

My only concern at this point is the default value of the hash. If we were t=
o use spl _object_hash, we could be setting a precedence that a hash must be=
 unique to each object.=20

Any thoughts on that?

>=20
>> If the desire is for it to contain 2, then spl_object_hash($a) already=20=

>> has that covered, I think.
>>=20
>> If the desire is for it to contain 1, then the proposal sounds like a=20
>> way to normalize Foo::stringifiedValueObjectEquivalent().
>=20
> You can describe it as such, but in a proper standartized way and with
> syntax that allows you to use same syntax constructs on all keys and not
> have to check each time if it's a special value and call a special
> function on it (same purpose as for __toString).
> --=20
> Stanislav Malyshev, Software Architect
> SugarCRM: http://www.sugarcrm.com/
>=20
> --=20
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>=20