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Date: Wed, 21 Jun 2023 22:08:00 -0500
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [Proposal] Introduce is operator
From: larry@garfieldtech.com ("Larry Garfield")

On Wed, Jun 21, 2023, at 5:44 PM, =D0=A3=D0=B4=D0=B0=D0=BB=D1=8C=D1=86=D0=
=BE=D0=B2 =D0=92=D0=B0=D0=BB=D0=B5=D0=BD=D1=82=D0=B8=D0=BD wrote:
> Hi internals,
>
> Today PHP is more typed than ever, however, one feature is still missi=
ng:
> ability to check complex variable types using standard type declaratio=
ns.
>
> For example, to check that $var is a nullable string one has to do
> `assert($var =3D=3D=3D null || is_string($var))`. To check that $var i=
s false or
> a countable iterator, one has to write `assert($var =3D=3D=3D false ||=
 ($var
> instanceof Countable && $var instanceof Iterator))`.
>
> I propose to add a new "is" operator that allows to have `assert($var =
is
> ?string)` and `assert($var is false|(Countable&Iterator))`. So it is
> similar to instanceof, but accepts any valid PHP type declaration on t=
he
> right side.
>
> WDYT?
>
> Regards,
> Valentin

There's already an RFC for that in the works, from Ilija and I: https://=
wiki.php.net/rfc/pattern-matching

"In the works" in this case means it's been designed and some preliminar=
y code written a while ago, but nothing submittable yet.  We're hoping t=
o get back to it in 8.4, as it's going to be a prerequisite for ADTs bei=
ng usable.  (cf: https://wiki.php.net/rfc/tagged_unions, though the desi=
gn there is out of date.)

So... hopefully stay tuned.

--Larry Garfield