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Reply-To: Levi Morrison <levi.morrison@datadoghq.com>
Date: Mon, 7 Nov 2022 09:50:10 -0700
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To: Ilija Tovilo <tovilo.ilija@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] ARRAY_UNIQUE_IDENTICAL option
From: internals@lists.php.net ("Levi Morrison via internals")

A bit off topic, but not entirely:

In my opinion, adding another flag isn't the _real_ fix. Any function
which does comparisons should take a callable for users to provide any
comparison they wish. An iteratively better API would be:

    function array_unique<T>(list<T> $array, callable(T $a, T $b): int
$comparator);

Of course, there are other things like instead of using int for `0`,
`-1`, `1`, we could have used an enum but we don't have one today. I
just mean the core idea of taking callable is better than mucking
around with flags while also allowing for custom comparison. Note that
it doesn't necessarily prevent optimizations either. For instance, if
they had passed `php_compare` or some function which represents `$a
<=> $b`, we could identify that just as we identify a specific flag
and take an optimized pass.

Note that as enums aren't "comparable" directly, we could have
provided a custom comparator in this case, no "fix" necessary in core.

----

Of course, this complaining doesn't fix the situation we are in. My
first impression is that might be better to provide one or more
alternative functions and to deprecate `array_unique`.