Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:108397
User-Agent: Cyrus-JMAP/3.1.7-802-g7a41c81-fmstable-20200203v1
Mime-Version: 1.0
Message-ID: <5f5a4ab3-e609-4324-b056-53f782f1a63b@www.fastmail.com>
In-Reply-To: <f0c665ca-02c3-da16-bb78-30d68f6e505e@aimeos.com>
References: <861afae0-4568-745f-6615-a252067cc506@aimeos.com>
 <f0c665ca-02c3-da16-bb78-30d68f6e505e@aimeos.com>
Date: Tue, 04 Feb 2020 11:18:22 -0600
To: "php internals" <internals@lists.php.net>
Content-Type: text/plain
Subject: Re: [PHP-DEV] Re: [RFC] "arrayable" pseudo type hint
From: larry@garfieldtech.com ("Larry Garfield")

On Tue, Feb 4, 2020, at 6:48 AM, Aimeos | Norbert Sendetzky wrote:
> I would like to modify my initial concept of an "arrayable" type because
> PHP core developers seems to be in favor of the upcoming union data
> types instead of adding a new "arrayable" pseudo type similar to "iterable".
> 
> So, I would like to propose an "Arrayable" interface that combines
> ArrayAccess, Countable and Traversable interfaces and adds a toArray()
> method:
> 
> interface Arrayable extends ArrayAccess, Countable, Traversable
> {
>     public function toArray() : array;
> }
> 
> Then, methods signatures can support array and Array-like objects:
> 
> function useArrayable( array|Arrayable $arg ) : array|Arrayable {
>     $cnt = count( $arg );
>     $value = $arg['key'];
>     foreach( $arg as $key => $entry );
>     is_object( $arg ) { $nativeArray = $arg->toArray(); }
>     return $arg;
> }
> 
> Adding a toArray() method also avoids controversy around using a magic
> __toArray() method, even if this would be easier for developers in this
> case.
> 
> If union data types are available and "iterable" is implemented as
> alias, an alias "arrayable" for "array|Arrayable" may be added as well.

The more I think on it, the less I like `arrayable`.  PHP arrays are a terrible data structure from a type system point of view, with too much functionality crammed into one variable type.

If you want an object that shoves all the various bits of arrayness into one object, there's already ArrayObject, which you can extend if desired.

Especially with union types, amalgam built in types like this are even less needed.

Aside from iterable, the only other built-in alias I would see is one for array|ArrayAccess.  But... it's now possible to do exactly like that, so I don't know how useful it would be.

--Larry Garfield