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Date: Wed, 24 Sep 2014 21:01:09 +0100
Cc: =?windows-1252?Q?Johannes_Schl=FCter?= <johannes@schlueters.de>,
 Nicolai Scheer <nicolai.scheer@gmail.com>,
 PHP Internals <internals@lists.php.net>
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To: Stas Malyshev <smalyshev@sugarcrm.com>
Subject: Re: [PHP-DEV] Invokation on __toString() for object used as array key
From: ajf@ajf.me (Andrea Faulds)


On 24 Sep 2014, at 20:56, Stas Malyshev <smalyshev@sugarcrm.com> wrote:

>> There the assumption would be that this leads to an array $a with two
>> elements, where in fact there is only one if __toString() is being
>> called. The only thing "making sense" would be using using the =
objects
>> identity (i.e. via spl_object_hash()) everything else leads to =
issues.
>=20
> This is a valid concern. For this, Java, for example, has separate
> methods hashCode() and toString(). Python has __str__, __repr__ and
> __hash__. Ruby has object.hash. So maybe we should have another magic,
> something like __hash(), that would produce a value for key? Then
> objects that implement __hash would be hashable and those that don't
> won't be, while still having usable __toString.

I=92m not sure that=92d make much sense. The object isn=92t the key, the =
value the magic method returns is. It would be quite odd to do this:

    $someArray =3D [$my__hashImplementingObject =3D> 1];
    var_dump($someArray);

And see something like this, because we=92ve called a hash function:

    array(1) {
        ["ec10e5a66e281d105f302cacfb1aaca8"]=3D>
        int(0)
    }

I don=92t really see what advantage this has over the normal __toString. =
Furthermore, having a special method we use to cast here that=92s used =
nowhere else seems weird.

Now, if we were to add actual object key support, that I might like. But =
if we=92re going to keep with just integers and strings, I=92d much =
prefer to just support __toString here. I think users are smart enough =
to understand that PHP arrays only have string or int keys, so it casts =
to a string.

--
Andrea Faulds
http://ajf.me/