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Date: Fri, 24 Apr 2020 16:33:24 +0200
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Subject: Re: [PHP-DEV] [RFC] Mixed type
From: bobwei9@hotmail.com (Bob Weinand)

Actually,

I forgot that for proper generics implementations, collections etc. will ob=
viously need to specify "allowing any type". As such the introduction of mi=
xed is pretty much necessary.

As in class Foo<A, B> { =E2=80=A6 } $foo =3D new Foo<mixed, int>;

As such, I'm actually in favor of introducing it.

Bob

> Am 24.04.2020 um 14:11 schrieb Bob Weinand <bobwei9@hotmail.com>:
>=20
> Hey Dan,
>=20
> this, I consider one of the few concepts which should never make it into =
PHP.
>=20
> In particular, the main problem with mixed is that it is a very easy "I h=
ave no idea how to type that properly, so just let's use mixed".
>=20
> And really, in general, except for some debug functions, mixed is just an=
 excuse to not use proper generics. I cannot think of non-debug scenarios w=
here we are juggling truly unknown types where the type is unidirectional.
> (Uni-directional means: there is no corresponding getting/forwarding func=
tion for an input.)
>=20
> Mixed is in almost every case just patching the holes in PHPs type system=
. And as such, I'd rather promote RFCs trying to properly fix the gaps in t=
he type system than supporting mixed.
>=20
> Mixed is a hack, do not use mixed.
>=20
> Bob
>=20
> P.s.: If you want to migrate your types and have an overview of what's al=
ready migrated, maybe just add a comment // type-migrated before or similar=
? But that's seriously not the business of the language.
>=20
>> Am 20.04.2020 um 13:17 schrieb Dan Ackroyd <danack@basereality.com>:
>>=20
>> Hi Internals,
>>=20
>> Here is an RFC for adding a 'mixed' type to the language:
>> https://wiki.php.net/rfc/mixed_type_v2
>> The RFC builds on an earlier draft by Michael Moravec.
>>=20
>> Part of the motivation for pursuing this RFC was my recent experience
>> in upgrading an application to PHP 7.4.
>>=20
>> Being able to add types to the application made the code much easier
>> to reason about, but there were places where I couldn't add type info
>> due to the lack of mixed. That made it hard to see if that piece of
>> code had been upgraded (but type info couldn't be added), or if that
>> code still needed to be upgraded.
>>=20
>> cheers
>> Dan
>> Ack
>>=20
>> --=20
>> PHP Internals - PHP Runtime Development Mailing List
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>>=20
>=20
> --=20
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>=20