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Date: Mon, 21 Oct 2024 13:20:51 +0000
To: PHP internals <internals@lists.php.net>
Subject: Re: [PHP-DEV] [RFC] Change behaviour of array sort functions to return a copy of the sorted array
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From: internals@gpb.moe ("Gina P. Banyard")


On Sunday, 20 October 2024 at 18:42, Gina P. Banyard <internals@gpb.moe> wr=
ote:

> Hello internals,
>=20
> I would like to propose a short RFC to make the return value of the sort(=
) and similar functions more useful:
> https://wiki.php.net/rfc/array-sort-return-array

I am going to respond out of threads.

This RFC does *NOT* change the by-ref parameter passing *NOR* the in-place =
sorting of these functions.
I don't see why people are thinking this would be changed, as I only ever t=
alk about the return value.
But I added a sentence in the Unaffected PHP Functionality section.

I really struggle to see the benefit of introducing new functions that woul=
d do the exact same thing as this RFC,
except the in-place modification, as seen by the already existing bikesheed=
ing on function naming.

For an example, I'm going to pull out my solution to day 1 of the 2022 adve=
nts of code:

https://github.com/Girgias/advent-of-code/blob/19283e1f5ef503c8a4478e58aaa5=
7ff2fb7164c7/2022/01/puzzle.php#L25

If we had a pipe operator, or if decided to write this less legible with ne=
sted calls, it would like this:

$elves =3D array_map(
    'array_sum',
    array_map(
        fn($v) =3D> explode("\n", $v),
        explode(
            "\n\n",
            $input
        )
    )
);
rsort($elves);
$top3 =3D array_slice($elves, 0, length: 3);

However, if the sort functions would return a useful value instead of `true=
` I could chain it together completely as follows:

$top3 =3D array_slice(
    rsort(
        array_map(
            'array_sum',
            array_map(
                fn($v) =3D> explode("\n", $v),
                explode(
                    "\n\n",
                    $input
                )
            )
        )
    ),
    0,
    length: 3
);

In either case, the fact the array is sorted in place is something I don't =
care, as it is just a temporary step.
However, in the current state, I need to stop chaining function calls just =
to be able to get the sorted array that I am going to process and discard a=
t the next function call.

This type of data processing pattern can be generalized to any collection o=
f data that needs to be sorted/filtered and processed upon.

This RFC is "just" making the return value of these functions *useful*.

Would a "proper" functional variant of these functions which do not take th=
e input argument by reference be useful? Yes.
Is this completely orthogonal to the point of this RFC? Also yes.

Best regards,

Gina P. Banyard