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To: Levi Morrison <levim@php.net>
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Cc: Niklas Keller <me@kelunik.com>, Andrea Faulds <ajf@ajf.me>,
 PHP internals <internals@lists.php.net>
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Date: Sat, 4 Feb 2017 00:57:07 +0100
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Subject: Re: [PHP-DEV] Re: [RFC][Discuss] Arrow Functions
From: bjorn.x.larsson@telia.com (=?UTF-8?Q?Bj=c3=b6rn_Larsson?=)

Den 2017-02-03 kl. 21:46, skrev Levi Morrison:
> On Fri, Feb 3, 2017 at 1:37 PM, Niklas Keller <me@kelunik.com> wrote:
>> 2017-02-03 21:23 GMT+01:00 Levi Morrison <levim@php.net>:
>>> On Fri, Feb 3, 2017 at 12:18 PM, Andrea Faulds <ajf@ajf.me> wrote:
>>>> Hi David,
>>>>
>>>> David Rodrigues wrote:
>>>>> Hello folks!
>>>>> I just not understand why "function" should be abbreviated. It's about
>>>>> "how
>>>>> less character better"? I don't see it too much on PHP. I guess that is
>>>>> more simple keep what exists current "function", that all knows about
>>>>> (that
>>>>> should be better than the next example):
>>>>>
>>>>> $mapped = array_map(function($x) => $x + $y); // vs current:
>>>>> $mapped = array_map(function($x) use($y) { return $x + $y });
>>>>
>>>> I feel the same way. It would be nice to have shorter syntax, but it
>>>> sacrifices readability and familiarity here, and adds yet another new
>>>> keyword.
>>>>
>>>> It also feels inconsistent… isn't "fn" just short for "function"? Why is
>>>> it
>>>> exclusive to the => syntax?
>>> This is not exactly on topic... unless you are implying you'd prefer
>>> the `|$x| => $x + $y`? Maybe you missed [this][1] message?
>>
>> Why is using "function" instead of "fn" not on topic?
> I did not ask for general syntax suggestions. What I am asking about
> is specifically what the preference people might have between these
> two options:
>
>      fn(params) => expr
>      |params| => expr
>
> As well as potential issues (thanks, Ilija, for pointing out a
> theoretical issue with union types).
>
> ----
>
> As a disclaimer I'm trying to guide the discussion to these two
> options, not suppress suggestions I don't like.
>
I can live with both, maybe with a preference for the
last one. Using function with another semantic I don't
like at all. Imagine for example if different kind of loops
had the same starting keyword (for for everything ;-).

Also using fn or || helps when searching in a codebase
for all ordinary functions and no arrow ones, e.g. grep
'function(\$' files would give everything with fucntion
keyword.

Anothe angle I came to think of is if PHP in the future
would have async / await functionality. How does that
play together with arrow functions? HHVM has some
example: https://docs.hhvm.com/hack/async/blocks

Anyway, I do appreciate that finally arrow functions in
PHP are on the horizon :-)

Regards //Björn Larsson