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Date: Mon, 03 Oct 2005 07:32:27 -0700
To: "Dmitry Stogov" <dmitry@zend.com>,"'Derick Rethans'" <derick@php.net>,
	"'PHP Developers Mailing List'" <internals@lists.php.net>
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	<002a01c5c823$97c04d20$e902a8c0@thinkpad>
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Subject: RE: [PHP-DEV] $ref =& $this;
From: andi@zend.com (Andi Gutmans)

Assigning to it will break "this" in the symbol table, or EG(This)? 
If it's the latter then it is a problem (and it's the reason I didn't 
support it to begin with).

Andi

At 07:05 AM 10/3/2005, Dmitry Stogov wrote:
>Hi,
>
>At first $ref =& $this; produced fatal error because of the bug (not by
>design).
>For example $ref->prop =& $this; worked and works without errors.
>
>So my patch shouldn't be reverted in any case.
>
>At second disallowing such assignments and passign $this by reference will
>breake a lot of PHP4 code (Mamaba CMS).
>In PHP4 passing $object by refernce and by value had completely different
>semantic.
>
>I don't see any reason to disallow 100% proper code (like the the
>following).
>
>class Child {
>   function Child($parent) {
>     $parent->children[] =& $this;
>   }
>}
>
>Of course using "=& $this" user can breake $this value, but other languages
>(C++) allows this too.
>I don't think we should be paranoiacs.
>
>Thanks. Dmitry.
>
>
> > -----Original Message-----
> > From: Derick Rethans [mailto:derick@php.net]
> > Sent: Monday, October 03, 2005 5:09 PM
> > To: PHP Developers Mailing List
> > Subject: [PHP-DEV] $ref =& $this;
> >
> >
> > Hello,
> >
> > Dmitry committed a fix earlier to ignore the & in the
> > statement above. I
> > think this is not a good thing to do as it's simply
> > conceptually wrong.
> > The first thing is that ignoring syntax without issuing a warning is
> > dubious because people might think it does actually work, and
> > secondly
> > because I think that the code above is wrong anyway - somewhat in the
> > same way that "$this = new foo();" is wrong.
> >
> > There is never any need to assign $this by reference, nor to
> > pass it by
> > reference to a function as it's an object anyway, making the
> > references
> > pointless - I would even go as far as disallowing passing $this by
> > references to a function - where the reference has to be
> > ignored again,
> > otherwise it allows you to chantge $this to a different object with:
> >
> > class Foo {
> >       function byRef(&$f) {
> >               $f = new Bar();
> >       }
> >
> >       function modifyThis() {
> >               $this->byRef($this);
> >       }
> > }
> >
> > I think we should prevent people from writing syntax like
> > this, as it is
> > not obvious what is going to happen. This means that we should revert
> > Dmitry's patch.
> >
> > regards,
> > Derick
> >
> > --
> > Derick Rethans
> > http://derickrethans.nl | http://ez.no | http://xdebug.org
> >
> > --
> > PHP Internals - PHP Runtime Development Mailing List
> > To unsubscribe, visit: http://www.php.net/unsub.php
> >
> >
>
>--
>PHP Internals - PHP Runtime Development Mailing List
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