Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 11 Aug 2010 14:57:47 +0100, Johannes Schlüter
johan...@schlueters.de wrote:
On Wed, 2010-08-11 at 14:38 +0100, Gustavo Lopes wrote:
I've updated the wiki page for Closures with objects extension with
things that are in Proposal A with modifications but are not
implemented:
http://wiki.php.net/rfc/closures/object-extension#status_as_of_august_10_2010
I propose an implementation of closures stored in properties used as
methods, as in:
$this-prop = function () { ...}
$this-prop();
[...]
I don#t have an opinion on this feature, yet, I like the current
class-based object model as reading code is relatively simple, with this
addition (and the fact that you can create properties on the fly) we
create a powerful tool for really hard to read code.
It's important to understand this is not mere syntactic sugar over
$a = $this-prop;
$a();
or call_user_func($this-prop). It actually allows executing closures in a
way that fails if the staticness or bound instance of the closure is not
what was expected.
See the beautiful tree graphs on the wiki page.
--
Gustavo Lopes
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Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 2010-08-11 at 14:38 +0100, Gustavo Lopes wrote:
I've updated the wiki page for Closures with objects extension with
things that are in Proposal A with modifications but are not implemented:
http://wiki.php.net/rfc/closures/object-extension#status_as_of_august_10_2010
I propose an implementation of closures stored in properties used as
methods, as in:
$this-prop = function () { ...}
$this-prop();
A few issues that may merit discussion (copied from the wiki page):
A few more things coming to mind without much thought:
* What if both a method and a property with the name exist?
* What about allowing properties with function names as strings or
array($obj_or_class, 'method'), won't that be needed for being
consistent with local variables?
* In the array($object, 'method') case: What's the scope
for $this?
I don#t have an opinion on this feature, yet, I like the current
class-based object model as reading code is relatively simple, with this
addition (and the fact that you can create properties on the fly) we
create a powerful tool for really hard to read code.
johannes
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PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 11 Aug 2010 14:57:47 +0100, Johannes Schlüter
johan...@schlueters.de wrote:
On Wed, 2010-08-11 at 14:38 +0100, Gustavo Lopes wrote:
I've updated the wiki page for Closures with objects extension with
things that are in Proposal A with modifications but are not
implemented:
http://wiki.php.net/rfc/closures/object-extension#status_as_of_august_10_2010
I propose an implementation of closures stored in properties used as
methods, as in:
$this-prop = function () { ...}
$this-prop();
A few issues that may merit discussion (copied from the wiki page):
A few more things coming to mind without much thought:
* What if both a method and a property with the name exist?
An existing method has priority over closure-as-method, just like it has
priority over __call. I implemented what was in the modified proposal A.
Personally, I think __call should have priority over closure-as-method so
as to not to break BC.
* What about allowing properties with function names as strings or
array($obj_or_class, 'method'), won't that be needed for being
consistent with local variables?
Well, you cannot do $a = 'phpinfo'; $a(); as well, so it's consistent
with that. I think what you refer to would only make sense if that were
allowed.
* In the array($object, 'method') case: What's the scope
for $this?
call_user_func(array($object, 'method')) is the same as $object-method(),
the calling scope is that whatever scope is defined for the closure. The
value of $this is the object that's bound to the closure; an E_WARNING
notice is raised if $this !== $object (as mentioned in the proposal).
class A {
public $prop;
}
$a1 = new A;
$a2 = new A;
$a1-prop = Closure::bind(function () { var_dump($this); }, $a2);
call_user_func(array($a1, 'prop'));
gives:
Warning: Closure called as method but bound object differs from containing
object in ...
object(A)#2 (1) {
[prop]=
NULL
}
I don#t have an opinion on this feature, yet, I like the current
class-based object model as reading code is relatively simple, with this
addition (and the fact that you can create properties on the fly) we
create a powerful tool for really hard to read code.
We could forbid using dynamic properties for this functionality, though
I'd say it's arguably useful.
--
Gustavo Lopes
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Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 2010-08-11 at 15:29 +0100, Gustavo Lopes wrote: * What about allowing properties with function names as strings or array($obj_or_class, 'method'), won't that be needed for being consistent with local variables? Well, you cannot do $a = 'phpinfo'; $a(); as well, so it's consistent with that. I think what you refer to would only make sense if that were allowed. You can. This is valid. johannes -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 11 Aug 2010 15:37:01 +0100, Johannes Schlüter johan...@schlueters.de wrote: On Wed, 2010-08-11 at 15:29 +0100, Gustavo Lopes wrote: * What about allowing properties with function names as strings or array($obj_or_class, 'method'), won't that be needed for being consistent with local variables? Well, you cannot do $a = 'phpinfo'; $a(); as well, so it's consistent with that. I think what you refer to would only make sense if that were allowed. You can. This is valid. Oh. I'll change it then. -- Gustavo Lopes -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Closures as methods (and Closure::bind)
On Wed, 11 Aug 2010 15:37:01 +0100, Johannes Schlüter johan...@schlueters.de wrote: On Wed, 2010-08-11 at 15:29 +0100, Gustavo Lopes wrote: * What about allowing properties with function names as strings or array($obj_or_class, 'method'), won't that be needed for being consistent with local variables? Well, you cannot do $a = 'phpinfo'; $a(); as well, so it's consistent with that. I think what you refer to would only make sense if that were allowed. You can. This is valid. OK, I know where I got this idea. $a = 'phpinfo'; $a(); is actually the only valid case. array callbacks or 'Foo::bar' are forbidden. In order to be called as instance methods, the closure properties needs to have a bound instance -- preferably -- very preferably -- the instance where the closure is stored. In this case, it doesn't make sense to allow 'function' to be called, because then we wouldn't have anything with which to fill the $this pointer. I guess it could make some sense for static calls, though. -- Gustavo Lopes -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
