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Date: Wed, 18 Nov 2009 09:53:06 +0000
Message-ID: <10845a340911180153g64333917p591dfff925f907fd@mail.gmail.com>
To: Christian Seiler <chris_se@gmx.net>
Cc: internals@lists.php.net
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Subject: Re: [PHP-DEV] Closures and $this
From: rquadling@googlemail.com (Richard Quadling)

2009/11/16 Christian Seiler <chris_se@gmx.net>:
> Hi,
>
> since a few months have passed since the last discussion on this topic
> and perhaps people had time to gather some experience with the current
> closure implementation in PHP 5.3 I'd like to restart the debate on
> $this in closures and object extension.
>
> Foreword: The discussion should center on the future behaviour of PHP 6
> ONLY. Whether or not a backport is even possible (binary compability
> etc.) or should even be done should be topic of a separate discussion
> and should *NOT* influence the decision. The ONLY goal of this
> discussion should be to agree on a SANE way of implementing $this for
> closures for PHP 6.
>
> I've updated the original RFC I wrote a tiny bit (I didn't change much):
>
> <http://wiki.php.net/rfc/closures/object-extension>
>
> The basic outline is the following:
>
> =C2=A0* In the first section I explain the general issue.
> =C2=A0* In the second section I show the proposals that were made on
> =C2=A0 internals@ before I wrote the RFC.
> =C2=A0* In the third section I compare the approaches and explain why
> =C2=A0 the approaches (B) and (D) are inconsistent.
> =C2=A0* In the fourth section I propose a new approach (bindTo) that
> =C2=A0 was only briefly discussed after the original RFC.
>
> Please read the complete RFC and try to understand the points I'm trying
> to make. If something is unclear, *please* ask first. In the past
> discussion I had the impression that a lot of people understood only
> partial aspects of the problem which made the discussion extremely
> noisy. I believe that is a disservice to the issue. However, now we have
> the huge advantage of NOT having an immanent deadline for a release. I
> hope this will enable a consensus on this issue.
>
> Discuss away!
>
> Regards,
> Christian
>
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>

I think the consistent mechanism is to have the binding done at
runtime and to be explicitly stated by the userland code.

$fn =3D function() use() bind($x) {
  // $this =3D whatever was bound, in this example $x
};

so, inside a class...

$fn =3D function() use() bind($this) {
  // $this would be the same as the $this of the class.
};

As for public/protected/private ...

$fn =3D function() use() bind() access(CLOSURE_PUBLIC |
CLOSURE_PROTECTED | CLOSURE_PRIVATE) {};

to control which properties/methods were available.

I'd be concerned about that this could be a shortcut to access
non-public properties/methods.

Richard.

-----
Richard Quadling
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