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Date: Thu, 24 Jul 2025 13:52:14 +0200
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
Subject: Re: [PHP-DEV] [RFC] Partial Function Application v2
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From: tim@bastelstu.be (=?UTF-8?Q?Tim_D=C3=BCsterhus?=)

Hi

Am 2025-07-24 12:03, schrieb Tim Düsterhus:
> I don't think they should. Specifically the (1) and (3) should not. My 
> expectation is that:
> 
>     $f = foo(a: ?, b: 2, c: ?);
>     $f(1, 3); // calls foo(1, 2, 3);
> 
> and
> 
>     $f = foo(c: ?, b: 2, a: ?);
>     $f(1, 3); // calls foo(3, 2, 1);
> 
> The order of the question marks should match the order of the 
> parameters in the resulting Closure, which is not necessarily the order 
> of the order parameters of the original function.

To add to that: By respecting the order of question marks as written, it 
would also make PFA easier to understand and also more powerful. After 
sending the email earlier, I came across this doctrine/collections PR, 
while reviewing some dependency upgrades: 
https://github.com/doctrine/collections/pull/424

When migrating the `findFirst()` method from a custom foreach loop to 
`array_find()`, they couldn't pass along the given callable directly, 
since Doctrine opted for a different parameter order. Thus they needed 
an intermediate Closure to swap the arguments. If the argument names for 
the function are known (which they are not in the Doctrine example, as 
it's an arbitrary Closure that is given), this would allow to swap 
arguments as necessary:

     function cb($key, $val) { … }

     array_find($array, cb(val: ?, key: ?)); // array_find expects 
$value, $key.

Best regards
Tim Düsterhus