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Date: Fri, 29 Jan 2021 11:16:20 +0100
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Subject: Re: [PHP-DEV] [DISCUSSION] ReflectionType::accepts
From: brendt@stitcher.io (Brent Roose)

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Hi Nikita

I was indeed thinking about the former: acceptsValue; but I would =
excpect that if the concrete value is a subtype of the current type, the =
fuction would also return true. What I'm basically interested in: will =
this method throw a type error when I pass this value? In other words: =
"will this method accept this value?"

Is that in line with your view on `acceptsValue`?=20

Kind regards
Brent

> On 29 Jan 2021, at 10:33, Nikita Popov <nikita.ppv@gmail.com> wrote:
>=20
> On Fri, Jan 29, 2021 at 9:15 AM Brent Roose <brendt@stitcher.io =
<mailto:brendt@stitcher.io>> wrote:
> Hi Internals
>=20
> Since the addition of union types, it has become a little more =
cumbersome to determine whether a given parameter type accepts specific =
input. Personally I've been reusing this code blob in several places =
because of it:
>=20
> ```
> /** @var \ReflectionNamedType[] $types */
> $types =3D match ($type::class) {
>     ReflectionUnionType::class =3D> $type->getTypes(),
>     ReflectionNamedType::class =3D> [$type],
> };
>=20
> foreach ($types as $type) {
>     if (! is_subclass_of($type->getName(), ShouldBeStored::class)) {
>         continue;
>     }
>=20
>     // =E2=80=A6
> }
> ```
>=20
> I wonder whether we would discuss adding a method on ReflectionType =
that accepts any given input, and tells you whether that input is valid =
for that type or not. I was thinking about =
`ReflectionType::accepts(string|object $input): bool` but we could =
discuss another name. With it, the above example could be refactored =
like so:
>=20
> ```
> if (! $type->accepts(ShouldBeStored::class)) {
>     return;
> }
>=20
> // =E2=80=A6
> ```
>=20
> I believe this method should accept both class names and objects to be =
consistent with the existing reflection API. It would also work with =
intersection types, if they are to be added some day.
>=20
> What do you think?
>=20
> Kind regards
> Brent
>=20
> There's two possible notions of what "accepts" does:
>=20
> * acceptsValue(), whether a given value satisfies the type. Probably =
needs a flag to determine whether strict_types semantics should be used =
or not.
>=20
> * isSubTypeOf(), whether a given type satisfies the type in a =
subtyping relationship.
>=20
> You seem to be mixing these two up into one concept, even though they =
are quite different. Which is the one you actually need? (I am much more =
open to providing the former than the latter.)
>=20
> Nikita


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