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 <8310f3fd-0011-970e-5379-b2b6e03942b2@gmail.com> <2347345.PIDvDuAF1L@arnaud-t490>
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Date: Mon, 13 Jun 2022 18:21:23 +0100
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To: Arnaud Le Blanc <arnaud.lb@gmail.com>
Cc: internals@lists.php.net, Rowan Tommins <rowan.collins@gmail.com>
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Subject: Re: [PHP-DEV] [RFC] Short Closures 2, aka auto-capture take 3
From: Danack@basereality.com (Dan Ackroyd)

Hi Arnaud,

Arnaud Le Blanc <arnaud.lb@gmail.com> wrote:
>
> Following your comment, I have clarified a few things in the "Auto-capture
> semantics" section. This includes a list of way in which these effects can be
> observed. These are really marginal cases that are not relevant for most
> programs.

Cool, thanks.

> Unfortunately, Arrow Functions already auto-capture today, so requiring a
> `use(*)` to enable auto-capture would be a breaking change.

I think there are two things that making this conversation be more
adversial than it could be otherwise:

1. Some people really want implicit auto-capture, while others are
deeply fearful of it. That comes more from the experience people have
from writing/reading different types of code leading them to have
different aesthetic preferences. Trying to persuade people their lived
experience is wrong, is hard.

2. The current situation of having to list all variables is kind of
annoying when it doesn't provide much value e.g. for stuff like:

function getCallback($foo, $bar, $quux)
{
    return function($x) use ($foo, $bar, $quux)
    {
        return $quux($foo, $bar, $x);
    }
}

Where the code that returns the closure is trivial having to list out
the full of captured variables does feel tedious, and doesn't provide
any value.

I realise it's annoying when people suggest expanding the scope of an
RFC, however...how would you feel about adding support for use(*) to
the current 'long closures'?

That way, people could choose between:

* Explicit capture of individual variables: function($x) use ($foo,
$bar, $quux) {...}
* Explicit capture of all relevant variables: function($x) use (*) {...}
* Implicit capture of all relevant variables, and fewer letters: fn($x) {...}

People who don't want implicit capture would be able tell their code
quality analysis tools to warn on any use of short closures (or
possibly better, warn when a variable has been captured). People who
do want implicit capture can use the short closures which always have
implicit capture.

cheers
Dan
Ack