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Date: Tue, 19 Mar 2013 21:43:03 +0100
To: =?UTF-8?Q?Mat=C4=ABss_Roberts_Treinis?= <mrtreinis@gmail.com>,PHP Development <internals@lists.php.net>
Message-ID: <5f39c9e5-14c7-4403-ab95-bd898b748e6a@email.android.com>
Subject: Re: [PHP-DEV] Proposal: new magic methods for Object references.
From: johannes@schlueters.de (=?ISO-8859-1?Q?Johannes_Schl=FCter?=)



"Matīss Roberts Treinis" <mrtreinis@gmail.com> wrote:

>Proposal:
>
>Two additional magic methods for PHP objects -
>
>__refer(void):
>
>Refer method is called whenever object's identifier is assigned to
>variable, if such method is present.
>Example:
>
>$foo = new Bar;
>$bar = $foo; //__refer invoked

This assignment is handled using PHP's copy on write mechanism for any variable. A change here has massive impact on any variable assignment, function parameter passing, ... and tons of internal places.

What we have is a hook for the objects own reference counting which is affected when an object refering to an object is used in write-context by the engine, that might easily be exteded but is rather useless. (It's trivial to create an interface or abstract base class providing this addref/delref info)

Unless you can provide a robust good patch without performance penalty in cases where this isn't used this will lead nowhere, and I doubt there is a way to come up with that. (rewriting the engine might be the closest approach)

johannes