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Date: Mon, 05 Oct 2020 12:00:26 +0200
To: Andreas Leathley <a.leathley@gmx.net>
Cc: internals@lists.php.net
In-Reply-To: <881e2335-5f81-0d79-6a17-06bc20f14223@gmx.net>
References: <CALZWoqU_qQQiQ5O6Pa8Upxo2FYZ2hpMA0dy9=CZndeEFsijgxA@mail.gmail.com> <446c9894-191f-e53b-4534-31c4e7b91d7b@gmail.com>
 <881e2335-5f81-0d79-6a17-06bc20f14223@gmx.net>
Message-ID: <7e50dba8b8749b9e32c803d7ded20fab84e21dc74ec9a55d8127e961bb036cd8@mahalux.com>
Subject: Re: [PHP-DEV] RFC: Support for multi-line arrow functions
From: vorismi3@fel.cvut.cz (=?UTF-8?Q?Michael_Vo=C5=99=C3=AD=C5=A1ek_-_=C4=8CVUT_FEL?=)

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Yes, "use (*)" is perfect!

With kind regards / Mit freundlichen Grüßen / S přátelským pozdravem,

Michael Voříšek

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 = function() use (*) {
>> $x = $y = $z = 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 $isMainNumber
> = 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 $isMainNumber
> = false): void
> {
> $this->transaction->run(function () use (*): void {
> // Do all SQL queries for the update
> });
> }
> 
> ```
> 
> This would also increase code readability.
> 
> --
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