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References: <CALZWoqU_qQQiQ5O6Pa8Upxo2FYZ2hpMA0dy9=CZndeEFsijgxA@mail.gmail.com>
In-Reply-To: <CALZWoqU_qQQiQ5O6Pa8Upxo2FYZ2hpMA0dy9=CZndeEFsijgxA@mail.gmail.com>
Date: Sat, 3 Oct 2020 23:39:32 +0200
Message-ID: <CADyq6sJdLuEscRBoxZKgQGOA=1PQo98ZF1L76-ffEKzbvV6nHg@mail.gmail.com>
To: Nuno Maduro <enunomaduro@gmail.com>
Cc: PHP Internals List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000062593505b0cb1629"
Subject: Re: [PHP-DEV] RFC: Support for multi-line arrow functions
From: ocramius@gmail.com (Marco Pivetta)

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Hey Nuno,
<http://ocramius.github.com/>


On Sat, Oct 3, 2020 at 11:09 PM Nuno Maduro <enunomaduro@gmail.com> wrote:

> Hey internals,
>
>
> A few days ago I opened a pull request that adds support for multi-line
> arrow functions in PHP: https://github.com/php/php-src/pull/6246.
>
>
> As you may already know, PHP 7.4 has introduced one-liner arrow functions
> (aka short closures). Now, this pull request adds the possibility of those
> arrow functions to be multi-line. Just like in Javascript, or Hack. Let's
> see an example:
>
>
> ```php
>
> $users = [/** */];
>
> $guestsIds = [/** */];
>
> $repository = /** */;
>
>
> $guests = array_filter($users, fn ($user) => {
>
>   $guest = $repository->findByUserId($user->id);
>
>
>   return $guest !== null && in_array($guest->id, $guestsIds);
>
> });
>
> ```
>
>
> In short, the advantages are:
>
> ```
>
> $values = array_filter($values, function ($value) use ($first, $second,
> $third) {
>
> // vs
>
> $values = array_filter($values, fn ($value) => {
>
> ```
>
>
> - Multi-line arrow functions don't require the `use` keyword to be able to
> access data from the outer scope.
>
> - Also, in some cases, `fn (/** */) => {` is just shorter and simpler than
> `function (/** */) use (/** */) {`.
>
>
> This pull request has been very well received by the community on Github,
> and also on Twitter:
> https://twitter.com/enunomaduro/status/1311572174256340992.
>
>
> So, I am writing this email to get your feedback about having this feature
> in the core of PHP. Note that, if eventually, you think it is a good idea
> to create an RFC on this, I will need to get some RFC karma - my wiki
> account is nunomaduro.
>

Overall, seems like unnecessary added syntax for something that already
works just fine.

Pros:

 * unclear

Cons:

 * more scope leak
 * +1 way to do what we already do just fine
 * more lexer/ast complexity for downstream projects

If you want to make an RFC about it, it really needs a compelling "pros"
section, because there aren't any, so far :-\

Greets,

Marco Pivetta

http://twitter.com/Ocramius

http://ocramius.github.com/

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