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Date: Fri, 17 Jan 2020 09:16:39 +0100
Cc: Levi Morrison via internals <internals@lists.php.net>
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Message-ID: <D9CF8C30-2599-49F7-8DB5-3F23E05E9E6A@stitcher.io>
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To: Aran Reeks <cdtreeks@gmail.com>
Subject: Re: [PHP-DEV] Typed array properties V2
From: brendt@stitcher.io (Brent Roose)

Hello all

It's a much-requested feature for years and years. My first thought was =
"we need generics, not this" but than I took 5 minutes to actually think =
about it. While the same, and much more, can be achieved with generics, =
it's a difficult feature to implement. There have been several RFCs for =
generics in the past, which failed. I know Levi Morisson was, at one =
point, looking at adding support for generics only in traits, because =
it's difficult to add them in other places.

While I still think generics would be a great feature, I now also =
believe it's worth looking at an "array of" type as something =
standalone. I've got no clue about the technical implications, but maybe =
suprting "array of" syntax is a lot more easy than full blown generics? =
Looking at my day to day work with PHP, I'dsay "array of" types would =
solve ~80% of my problems with PHP's current type system, and I figure =
there are lots of developers in a similar situation. If I remember =
correct from my college days, Java also supports both styles: Int[] and =
ArrayList<Int>.

All that to say that maybe it's worth the effort looking at "array of" =
types as something different than generics?

Kind regards
Brent

> On 17 Jan 2020, at 08:50, Aran Reeks <cdtreeks@gmail.com> wrote:
>=20
> Hi Internals,
>=20
> I'd like to kick off a conversation to capture everyone else's =
thoughts on
> tweaking / improving typed properties for arrays (for a PHP 8.x =
release).
>=20
> With all the work done lately to greatly improve the type support in =
PHP
> (which is amazing by the way), I'm finding for the most part, I'm no =
longer
> needing to Docblock as much of my code which is lovely.
>=20
> That said, there's a common use case that keeps me going back to them =
which
> I think would be a good thing for PHP to try and solve as a language
> feature - better typing of arrays to type their properties.
>=20
> IDEs like PHPStorm handle this structure already hence sticking to =
that as
> a starting point...
>=20
> @returns []int
>=20
> This would designate the return of an array where all its keys are =
that of
> the int type, but it works for any type.
>=20
> With that in mind, it might also make sense to allow a shorthand array
> alias for array types anyway - array -> [].
>=20
> To use actual PHP examples, this would mean the following would be
> supported:
>=20
> // Typed array properties ...values would follow any existing PHO type
> function returnsIntArray(): []int;
> function returnsClassArray(): []Class;
>=20
> // The same outcome
> function returnsArray(): array;
> function returnsArray(): [];
>=20
> I welcome all your thoughts on this proposal.
>=20
> Many thanks,
> Aran