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To: "'Aimeos | Norbert Sendetzky'" <norbert@aimeos.com>,
	<internals@lists.php.net>
References: <861afae0-4568-745f-6615-a252067cc506@aimeos.com>
In-Reply-To: <861afae0-4568-745f-6615-a252067cc506@aimeos.com>
Date: Sun, 24 Nov 2019 23:54:48 +0800
Message-ID: <003801d5a2df$801404e0$803c0ea0$@jhdxr.com>
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Subject: RE: [PHP-DEV] [RFC] "arrayable" pseudo type hint
From: me@jhdxr.com (=?utf-8?b?Q0hVIFpoYW93ZWk=?=)

> This proposal is not obsolete by the implementation of union types =
(i.e.
> array|Traversable) because union data types are types/interfaces
> combined by OR. "arrayable" is a combination of OR and AND:
>=20
> array|ArrayAccess&Countable&Traversable

True. But it's also easy to implement in userland. Just create a new =
interface that extends these three interfaces, then union types can =
work.

```php
interface Arrayable extends ArrayAccess, Countable, Traversable {}

function array_x (array|Arrayable $arr) {}
```

This is not something that userland cannot implement or very difficult =
to implement. IMO it will make php more complex if we include this in =
the core. Actually what you suggested has been totally covered by the =
future scopes of the union types RFC. If you really want to explore this =
idea, I think they are worth more attention, instead of this specific =
case.=20

Regards,
CHU Zhaowei

> -----Original Message-----
> From: Aimeos | Norbert Sendetzky <norbert@aimeos.com>
> Sent: Wednesday, November 20, 2019 6:21 AM
> To: internals@lists.php.net
> Subject: [PHP-DEV] [RFC] "arrayable" pseudo type hint
>=20
> Since PHP 7.1, there's the "iterable" pseudo type hint that matches =
"array" or
> "Traversable".
>=20
> PHP frameworks would profit from support of an "arrayable" pseudo type =
hint
> that matches "array" and all objects that can be used like arrays.
>=20
> For that, "arrayable" objects have to implement these interfaces:
> - ArrayAccess
> - Countable
> - Traversable (i.e. either Iterator or IteratorAggregate)
>=20
>=20
> Implementing "arrayable" pseudo type, we could pass arrays or all =
objects that
> can be used like arrays to methods and do:
>=20
> function useArrayable( arrayable $arg ) : arrayable {
>     $cnt =3D count( $arg );
>     $value =3D $arg['key'];
>     foreach( $arg as $key =3D> $entry );
>     return $arg;
> }
>=20
>=20
> Best use cases are:
>=20
> - Laravel Collection
> =
(https://github.com/laravel/framework/blob/6.x/src/Illuminate/Support/Col=
lect
> ion.php)
>=20
> - Aimeos Map (https://github.com/aimeos/map)
>=20
>=20
> No new interface is proposed because we can check if objects =
implement:
>=20
> ArrayAccess && Countable && Traversable
>=20
>=20
> Because "array" !=3D=3D "arrayable", "arrayable objects will not be =
accepted by
> array_* functions and all functions that only use "array" as type hint =
for
> parameters and return types.
>=20
>=20
> This proposal is not obsolete by the implementation of union types =
(i.e.
> array|Traversable) because union data types are types/interfaces
> combined by OR. "arrayable" is a combination of OR and AND:
>=20
> array|ArrayAccess&Countable&Traversable
>=20
>=20
> Also, "arrayable" won't supersede "iterable" because
>=20
> - "iterable" matches arrays, iterators and generators
>=20
> - "arrayable" matches arrays and objects that can be used like arrays
>=20
>=20
> "Can be used like arrays" doesn't include support for empty() because =
it works
> for empty arrays but not for "arrayable" objects without elements.
> If possible and requested, this may be addressed by another RFC.
>=20
>=20
> As Larry Garfield suggested, this pre-RFC proposes concentrates on the
> "arrayable" pseudo type only.
>=20
> It does NOT discusses that:
>=20
> - arrayable objects can be converted to arrays (Steven Wade works on =
an RFC
> for a __toArray() magic function)
>=20
> - ArrayObject or any other arrayable object makes the array_* =
functions less
> relevant in the future
>=20
> - arrayable objects can be passed to array_* functions in the future
>=20
> --
> PHP Internals - PHP Runtime Development Mailing List To unsubscribe, =
visit:
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>=20