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To: Nikita Popov <nikita.ppv@gmail.com>
References: <CAF+90c9YZcrquGfS4h3x1a+codkCFLarAThsOXcN69RCTvbAFA@mail.gmail.com>
Cc: PHP internals <internals@lists.php.net>
Message-ID: <955a8f0c-b2b3-854f-7360-dfa60bd6d292@telia.com>
Date: Thu, 14 Mar 2019 00:01:02 +0100
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Subject: Re: [PHP-DEV] [RFC] Arrow functions / short closures
From: bjorn.x.larsson@telia.com (=?UTF-8?Q?Bj=c3=b6rn_Larsson?=)

Den 2019-03-13 kl. 16:56, skrev Nikita Popov:
> Hi internals,
>
> Motivated by the recent list comprehensions RFC, I think it's time we took
> another look at short closures:
>
> https://wiki.php.net/rfc/arrow_functions_v2
>
> This is based on a previous (withdrawn) proposal by Levi & Bob. It uses the
> syntax
>
>      fn($x) => $x * $multiplier
>
> and implicit by-value variable binding. This example is roughly equivalent
> to:
>
>      function($x) use($multiplier) { return $x * $multiplier; }
>
> The RFC contains a detailed discussion of syntax choices and binding modes.
>
> Regards,
> Nikita

Thanks for bringing this forward Nikita!

I recall from the earlier discussions 2017 that also the
lambda as a keyword was considered. I would like to
bring that forward as one option, maybe less impact
on existing code as a reserved keyword.

An advantage of not having a keyword /prefix could be
that for simple arrow functions no parenthesis is needed
and readability is improved:
$someDict->map(fn($v) => $v * 2)->filter(fn($v) => $v % 3);
$someDict->map(\($v) => $v * 2)->filter(\($v) => $v % 3);
$someDict->map(^($v) => $v * 2)->filter(^($v) => $v % 3);
vs
$someDict->map($v ==> $v * 2)->filter($v ==> $v % 3);
$someDict->map($v ~> $v * 2)->filter($v ~> $v % 3);

r//Björn L