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Date: Sat, 25 Feb 2023 06:41:38 +1000
Message-ID: <CAKVXxD_1L6L5BJ-yqggpaB_4yAVwWXNs__0AOw3SScXU0Y1W2A@mail.gmail.com>
To: Robert Landers <landers.robert@gmail.com>
Cc: internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] RFC idea: array_*(Enum)
From: mickmackusa@gmail.com (mickmackusa)

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On Thursday, February 23, 2023, Robert Landers <landers.robert@gmail.com>
wrote:

> Hello, internals,
>
> Currently, this is an Error:
>
> $allowedRoles = [Role::Admin];
> $hasRoles = [Role::User, Role::Admin];
>
> if(!empty(array_intersect($allowedRoles, $hasRoles))) doSomething();
>
> This is an error because enums cannot be cast to a string (and trying
> to make them stringable is not allowed) and many array functions
> expect something stringable. To work around this limitation, the above
> example must be rewritten like this:
>
> array_uintersect($allowedRles, $hasRoles, fn($l, $r) => $l === $r ? 0 :
> 1));
>
> Robert Landers
> Software Engineer
> Utrecht NL
>

----

 ...I'd like to add as an aside that:

if(!empty(array_intersect($allowedRoles, $hasRoles)))

is more simply written as

if (array_intersect($allowedRoles, $hasRoles))

--

And for anyone unfamiliar with array_udiff_ and array_uintersect_ functions:

1. The two variables in their callback function signature do not relate by
position to the input arrays. This is why it is common to use $a and $b (as
is common when calling usort()). In other words, the first input array's
data may occur as the first parameter in the callback or the second
parameter (like wise with subsequent input arrays).

2. The return value from these functions is expected to be an integer from
the result of a three-way comparison -- not the int value of a binary
evaluation.  Most simply, make a habit of implementing the spaceship
operator (<=>). See "array_uintersect() gives unexpected results when
callback only returns 0 or 1" @ https://stackoverflow.com/q/8176881/2943403

Another example:
https://stackoverflow.com/a/71049380/2943403

The deep dive: https://stackoverflow.com/a/70817582/2943403

mickmackusa

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