Newsgroups: php.internals
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Xref: news.php.net php.internals:109835
Date: Fri, 24 Apr 2020 16:10:14 +0000
To: Dan Ackroyd <Danack@basereality.com>
Cc: "internals@lists.php.net" <internals@lists.php.net>
Reply-To: moliata <moliata@protonmail.com>
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Subject: Re: [PHP-DEV] Typed callable properties
From: moliata@protonmail.com (moliata)

Hello,

I would like to correct myself (credits to Marco Pivetta for informing me)
regarding union types. While we still wouldn't be able to declare a type al=
ias
as `callable` and then use it in properties, technically speaking
`string|array|object` would allow to pass callables. As such, my point abou=
t
union types is invalid.


Best regards,
Benas Seliuginas

=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original Me=
ssage =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90
On Wednesday, April 22, 2020 7:56 PM, moliata <moliata@protonmail.com> wrot=
e:

> Hello,
>
> thank you for your opinion. In response to you mentioning that fixing thi=
s
> problem would be a huge amount of work, I would like to reiterate the ide=
a of
> simply ignoring context-dependent problems for the time being. In fact, w=
e can
> observe this behavior in parameter/return type hints already. As such, it
> doesn't make sense to make just property type hints a special case/except=
ion.
>
> Moreover, I oversaw Sara Golemon's comment in the `mixed pseudo type` RFC=
 that
> she would like to use type aliasing and union types instead, at least in =
the
> long run. The problem that comes up with this approach is that even if we=
 did
> something like this:
> `use mixed as string|int|...|callable;`
> ...we couldn't apply this `mixed` type alias to properties as callable ty=
pe is
> not allowed to be used with them.
>
> Best regards,
> Benas Seliuginas
>
> =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original =
Message =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90
> On Wednesday, April 22, 2020 5:29 PM, Dan Ackroyd Danack@basereality.com =
wrote:
>
> > On Tue, 21 Apr 2020 at 14:08, moliata moliata@protonmail.com wrote:
> >
> > >
> >
> > > I wanted to ignite a friendly discussion whether
> > > PHP should allow typed callable properties.
> >
> > IMO no.
> > Trying to fix the problems with callables would be a huge amount of
> > work, and not actually give that much benefit. Even just documenting
> > the problems with callables* is a non-trivial amount of work, and I
> > suspect there are many horrors lurking with the SPL code related to
> > them.
> >
> > > I believe we should look into...
> >
> > I'm pretty sure that choosing a different problem to solve that:
> >
> > -   would be easier to solve.
> >
> > -   provide more benefit in the long term.
> >
> > -   not require breaking a lot of userland + internal code immediately,
> >     but instead allow for migration over a longer period.
> >     My thoughts on adding 'function types' are here:
> >     https://github.com/Danack/FunctionTypes/blob/master/function_type_r=
fc.md
> >     There's still more than a couple of known problems that need to be
> >     worked through, as well as probably unknown problems lurking. As em=
ail
> >     is not a good format for carrying out discussions, if people want t=
o
> >     take part in that discussion, doing it in that repo would be better
> >     imo.
> >     Assuming the problems remaining can be addressed, that would give u=
s a
> >     more useful feature, and the existing 'callables' can be slowly
> >     deprecated and maybe removed from PHP in the distant future.
> >     cheers
> >     Dan
> >     Ack
> >     *[problems with callables] - https://wiki.php.net/rfc/consistent_ca=
llables
> >