> Is it `returnType as $thing` ? That doesn't read well, but I don't see
us making return type movable. as/use should be placable in either order,
but maybe we give them required order anyway?
I don't know if that would be a problem, because today we can have it
"function(): Type use($x)", so "Type use($x)"? I have to agree that it may
sound strange at first, but I also can't imagine many ways of doing things
differently without creating more complexities.
(1) function as $lambda (... $args): returnType use ($captures...) {}
(2) function (... $args) as $lambda: returnType use ($captures...) {}
(3) function (... $args): returnType as $lambda use ($captures...) {} //
original suggestion
(4) function (... $args): returnType use ($captures...) as $lambda {}
(4.b) function (... $args): returnType as $lambda {} // without use() will
be same as (3)
Or, define a "inline function" with its own name, visible only within the
scope itself. Similar to how JS works.
(5) function $lambda(... $args): returnType use ($captures...) {}
To be honest, as I typed what came to mind, I ended up preferring this last
option.
JS way:
function fb(n) {
if (n === 0) return 0;
if (n === 1) return 1;
return fb(n - 1) + fb(n - 2);
}
PHP (self-referenced) way:
function $fb($n): int {
if ($n === 0) return 0;
if ($n === 1) return 1;
return $fb($n - 1) + $fb($n - 2);
}
Currently PHP will accepts the same JS solution, but it will exposes fb()
to global scope and could causes errors:
function test() {
function fb($n): int
{
if ($n === 0) return 0;
if ($n === 1) return 1;
return fb($n - 1) + fb($n - 2);
}
var_dump(fb(10));
}
test();
test(); // Fatal error: Cannot redeclare fb()
Atenciosamente,
David Rodrigues
Em sex., 20 de nov. de 2020 às 12:14, Sara Golemon <poll...@php.net>
escreveu:
> On Wed, Nov 11, 2020 at 12:37 PM David Rodrigues <david.pro...@gmail.com>
> wrote:
>
>> My suggestion is to reuse the keyword `as` to set a variable that will
>> represent its own closure. It is more flexible once that we could choose
>> any name and reuse in nested closures. It is pretty similar to how SQL
>> works too.
>>
>> function fn1() as $lambda1 {
>> return function() as $lambda2 use ($lambda1) {
>> return [ gettype($lambda1), gettype($lambda2) ];
>> };
>> }
>>
>>
> My initial reaction to this is: Technically doable (easy even), but looks
> a bit... ugly? weird? surprising?
>
> I think my main objection to it is how much is now stacked after the
> parameter list:
>
> function($args...) : returnType as $local use ($captures...) {
> ...
> };
>
> That's a lot of... stuff (granted, we have most of it already) and how it
> looks when stacked together gets funky.
>
> Is it `returnType as $thing` ? That doesn't read well, but I don't see us
> making return type movable. as/use should be placable in either order, but
> maybe we give them required order anyway?
>
> TLDR; Long winded way to say I'm not inherently against this, and I like
> the idea of a lambda being able to recurse (not that I can ever recall
> having use for it, but maybe I fell back on named functions for that), I
> just think it's getting a bit wordy.
>
> -Sara
>
