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Date: Thu, 9 Jun 2022 21:39:20 +0200
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To: Nikita Popov <nikita.ppv@gmail.com>
Cc: Arnaud Le Blanc <arnaud.lb@gmail.com>, Larry Garfield <larry@garfieldtech.com>, 
	PHP Internals List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="000000000000167ded05e108fbd5"
Subject: Re: [PHP-DEV] [RFC] Short Closures 2, aka auto-capture take 3
From: ocramius@gmail.com (Marco Pivetta)

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Hey Nikita,

On Thu, 9 Jun 2022 at 21:35, Nikita Popov <nikita.ppv@gmail.com> wrote:

> On Thu, Jun 9, 2022 at 9:29 PM Marco Pivetta <ocramius@gmail.com> wrote:
>
>>
>> On Thu, 9 Jun 2022 at 21:27, Nikita Popov <nikita.ppv@gmail.com> wrote:
>>
>>> On Thu, Jun 9, 2022 at 8:15 PM Arnaud Le Blanc <arnaud.lb@gmail.com>
>>> wrote:
>>>
>>>> > Would that allow us to get rid of `static fn () {` declarations, when
>>>> > creating one of these closures in an instance method context?
>>>>
>>>> It would be great to get rid of this, but ideally this would apply to
>>>> Arrow
>>>> Functions and Anonymous Functions as well. This could be a separate RFC.
>>>>
>>>
>>> I've tried this in the past, and this is not possible due to implicit
>>> $this uses. See
>>> https://wiki.php.net/rfc/arrow_functions_v2#this_binding_and_static_arrow_functions
>>> for a brief note on this. The tl;dr is that if your closure does "fn() =>
>>> Foo::bar()" and Foo happens to be a parent of your current scope and bar()
>>> a non-static method, then this performs a scoped instance call that
>>> inherits $this. Not binding $this here would result in an Error exception,
>>> but the compiler doesn't have any way to know that $this needs to be bound.
>>>
>>> Regards,
>>> Nikita
>>>
>>
>> Hey Nikita,
>>
>> Do you have another example? Calling instance methods statically is...
>> well... deserving a hard crash :|
>>
>
> Maybe easier to understand if you replace Foo::bar() with parent::bar()?
> That's the most common spelling for this type of call.
>
> I agree that the syntax we use for this is unfortunate (because it is
> syntactically indistinguishable from a static method call, which it is
> *not*), but that's what we have right now, and we can hardly just stop
> supporting it.
>

Dunno, it's a new construct, so perhaps we could do something about it.
I'm not suggesting we change the existing `fn` or `function` declarations,
but in this case, we're introducing a new construct, and some work already
went in to do the eager discovery of by-val variables.

Heck, variable variables already wouldn't work here, according to this RFC
:D

Marco Pivetta

https://twitter.com/Ocramius

https://ocramius.github.io/

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