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Date: Fri, 15 Nov 2013 11:30:41 +0000
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To: Chris London <me@chrislondon.co>
Cc: "internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=20cf30223b13397e1504eb358759
Subject: Re: [PHP-DEV] Proposal: Type Casting User Classes
From: phoenix@jonstirling.co.uk (Jonny Stirling)

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As a thought. Would it not be possible to, instead of implementing a new
__cast method, make use of the existing __clone functionality? Effectively
aren't you trying to clone one object into another just of another type?

While I can't think of many use cases off the top of my head, I certainly
see the benefit of this proposal and it doesn't seem to have any BC that I
can see.

(First post so please excuse me if I'm missing things / making a daft
point.)

Cheers.
Jonny.


On Thu, Nov 14, 2013 at 6:39 PM, Chris London <me@chrislondon.co> wrote:

> Hey everyone,
>
> I want to get a feel for something I would like to implement into PHP core.
>  I would like to be able to cast objects to my own class types.  Similar to
> already available PHP syntax:
>
> $foo = (string) $bar;
>
> The syntax would look like this:
>
> $foo = (\My\FooObject) $bar;
>
> It would also support:
>
> $foo = ( (\My\FooObject) $bar )->myFooObjectFunction();
>
> I'm still trying to decide what would happen internally and I would like
> some feedback.  I'm thinking of 3 different things it could do:
>
> 1) Directly change the class type, functionally equivalent to:
>
>     function castType($object, $type) {
>         return unserialize(preg_replace("/^O:[0-9]+:\"[^\"]+\":/i",
>     "O:".strlen($type).":\"$type\":", serialize($object)));
>     }
>
> 2) Throw a fatal error if the object doesn't match the type trying to be
> cast.
>
> 3) Add a new static magic method called __cast() that would allow the
> developer to decide what happens. Like this:
>
> namespace \My;
>
> class FooObject {
>     public static function __cast($foo) {
>         // Do stuff here
>         return new FooObject;
>     }
> }
>
> I'm willing to implement this myself if everybody else likes this idea.
>  Thanks!
>
> Chris London
>

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