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To: Nikita Popov <nikita.ppv@gmail.com>, Larry Garfield
	<larry@garfieldtech.com>
CC: php internals <internals@lists.php.net>
Thread-Topic: [PHP-DEV] [RFC] Enumerations
Thread-Index: AQHWypS0dp+yj+uVBEGwghKNxSJW26nrcReAgAB3+fI=
Date: Mon, 7 Dec 2020 17:48:59 +0000
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Subject: Re: [PHP-DEV] [RFC] Enumerations
From: tysonandre775@hotmail.com (tyson andre)

Hi Nikita,=0A=
=0A=
> > At present, no.=A0 They're "just" objects, and you can't assign an obje=
ct=0A=
> > to a constant.=A0 Unfortunately I'm not sure how to enable that without=
=0A=
> > making them not-objects, which introduces all sorts of other complexity=
.=0A=
>=0A=
> This should at the least be clarified in the RFC. Is this a limitation fo=
r=0A=
> constants specifically, or anything using constexpr initializers? For=0A=
> example, is writing "function foo(MyEnum $e =3D MyEnum::SomeDefaultCase)"=
=0A=
> possibly? It would be a significant limitation if it weren't.=0A=
> =0A=
> Generally, I think the limitation on objects in constants is mostly=0A=
> artificial and you should consider lifting it as part of this RFC.=0A=
> Previously you simply couldn't create an object in a constexpr initialize=
r,=0A=
> so supporting this wasn't really relevant. With enums, this becomes=0A=
> important.=0A=
=0A=
I agree it should be clarified (and have phpt tests).=0A=
=0A=
Another option would be to lift the limitation on objects in constant expre=
ssion,=0A=
but only on immutable objects.=0A=
(currently just enum values)=0A=
=0A=
There's a range of opinions on internals over what a constant would ideally=
 be.=0A=
(something that is actually constant and not dependent on environment to ma=
ke code as readable as possible,=0A=
or something that does not change at runtime, etc.)=0A=
So there may be objections if the change introduces the ability to write co=
de like this,=0A=
but maybe more developers would find supporting only enums acceptable (cont=
inue throwing for non-enums):=0A=
=0A=
=0A=
```=0A=
define(CONFIGURATION, new stdClass());=0A=
class X { const CONFIGURATION =3D CONFIGURATION; }=0A=
X::CONFIGURATION->endpoints =3D [$dynamicUrl];=0A=
// do stuff=0A=
X::CONFIGURATION->endpoints =3D [$otherDynamicUrl];=0A=
```=0A=
=0A=
Then again, this suggestion to only support enums may also be an unsatisfyi=
ng compromise.=0A=
=0A=
Regards,=0A=
- Tyson=