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Date: Mon, 2 Feb 2015 09:06:59 -0700
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To: Andrea Faulds <ajf@ajf.me>
Cc: Nikita Popov <nikita.ppv@gmail.com>, PHP Internals List <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [VOTE] Combined Comparison (Spaceship) Operator
From: levim@php.net (Levi Morrison)

On Mon, Feb 2, 2015 at 8:27 AM, Andrea Faulds <ajf@ajf.me> wrote:
> Hey Nikita,
>
>> On 2 Feb 2015, at 13:49, Nikita Popov <nikita.ppv@gmail.com> wrote:
>>
>> I've voted -1 because I think this should be a function and not an opera=
tor. compare($a, $b) is more obvious than $a <=3D> $b and it's not like wri=
ting comparison functions is such a super common use case that it needs the=
 extra brevity of an operator. A function can furthermore be used as a call=
back, while an operator requires a wrapping closure.
>
> There=E2=80=99s no actual use for the bare comparison operation as a call=
back, though: usort($foo, =E2=80=98compare=E2=80=99); would just be a slow =
version of sort($foo);

For this particular use-case you are correct, but usually I use custom
callbacks for something more interesting, such as comparing one value
and then comparing another based on the result. Perhaps the callback
is higher-level:

function (callable $comparator) {
  return function ($selector) use ($comparator) {
    return function ($a, $b) use($selector, $comparator) {
      return $comparator($selector($a), $selector($b));
    };
  };
}

Maybe I'm the only one doing stuff like this, but it's not uncommon for me =
^^