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Date: Mon, 5 Oct 2020 12:08:26 +0200
Message-ID: <CANS-=pf0J3kmybt69a6uhPO8QmCJtBGoHat+x4ngp0AqJpX9+w@mail.gmail.com>
To: =?UTF-8?B?TWljaGFlbCBWb8WZw63FoWVrIC0gxIxWVVQgRkVM?= <vorismi3@fel.cvut.cz>
Cc: Andreas Leathley <a.leathley@gmx.net>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] RFC: Support for multi-line arrow functions
From: kjarli@gmail.com (Lynn)

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On Mon, Oct 5, 2020 at 12:00 PM Michael Vo=C5=99=C3=AD=C5=A1ek - =C4=8CVUT =
FEL <
vorismi3@fel.cvut.cz> wrote:

> Yes, "use (*)" is perfect!
>
> With kind regards / Mit freundlichen Gr=C3=BC=C3=9Fen / S p=C5=99=C3=A1te=
lsk=C3=BDm pozdravem,
>
> Michael Vo=C5=99=C3=AD=C5=A1ek
>
> On 5 Oct 2020 11:57, Andreas Leathley wrote:
>
> > On 04.10.20 22:08, Rowan Tommins wrote:
> >
> >> If we added an opt-in syntax for "capture everything", we might
> >> instead write this:
> >>
> >> $f =3D function() use (*) {
> >> $x =3D $y =3D $z =3D null;
> >> }
> >>
> >> Without re-initialising all local variables, we would no longer be
> >> able to know if they were actually local without looking at the
> >> surrounding scope for a value that might be captured. I am unconvinced
> >> by this trade-off of opt-out instead of opt-in.
> >>
> >> One use case I've seen proposed is closures which capture a large
> >> number of variables; I would be interested to see an example where
> >> this is the case and is not a "code smell" in the same way as
> >> requiring a large number of parameters.
> >
> > Something like "use (*)" seems like a great enhancement to me. I often
> > use a wrapper function for SQL transactions, something like:
> >
> > ```php
> > public function update(int $numberId, int $addressId, bool $isMainNumbe=
r
> > =3D false): void
> > {
> > $this->transaction->run(function () use ($numberId, $addressId,
> > $isMainNumber): void {
> > // Do all SQL queries for the update
> > });
> > }
> >
> > ```
> >
> > In these cases there is a lot of redundancy because of having to import
> > the variables, and if a variable is added, it has to be added in two
> > places in a slightly different way. The following would be much nicer:
> >
> > ```php
> > public function update(int $numberId, int $addressId, bool $isMainNumbe=
r
> > =3D false): void
> > {
> > $this->transaction->run(function () use (*): void {
> > // Do all SQL queries for the update
> > });
> > }
> >
> > ```
> >
> > This would also increase code readability.
> >
> > --
> > PHP Internals - PHP Runtime Development Mailing List
> > To unsubscribe, visit: https://www.php.net/unsub.php


How should php deal with the scenario where you want to `use` everything
and have one variable by reference?

```
function () use (*, &$butNotThisOne) {};
```

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