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Date: Sun, 17 Nov 2019 18:28:34 -0500
In-Reply-To: <461958fe-182e-59bf-9fdb-b110fd09e2b2@aimeos.com>
Cc: Aimeos | Norbert Sendetzky <norbert@aimeos.com>
To: PHP internals <internals@lists.php.net>
References: <461958fe-182e-59bf-9fdb-b110fd09e2b2@aimeos.com>
Subject: Re: [PHP-DEV] Concept: "arrayable" pseudo type and \Arrayable
 interface
From: mike@newclarity.net (Mike Schinkel)

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> On Nov 17, 2019, at 9:41 AM, Aimeos | Norbert Sendetzky =
<norbert@aimeos.com> wrote:
>=20
> Since PHP 7.1 there's the "iterable" pseudo type hint that matches
> "array" and "Traversable".
>=20
> PHP frameworks would profit from support of an "arrayable" pseudo type
> hint that matches "array" and all objects that implements =
"Traversable",
> "ArrayAccess" and "Countable".

If we are going to open up arrays for enhancement in PHP 8 I would ask =
that we seriously consider addressing the various differences between a =
built-in array and an instance of ArrayObject and/or the related =
associated interfaces such that the objects can be used interchangeably =
with a built-in array, i.e. that ArrayObject and the related associated =
interfaces can fully replace the use of arrays when refactoring.

Specifically I would propose that we provide some type of mechanism that =
would allow the developer to cause is_array() to return true on an =
ArrayObject/interfaces.  Maybe something like this (I have not =
considered all the special cases, I am just spitballing in concept =
here):

class MyArray extends ArrayObject {
   function __AsArray() {
      return true;
   }
   function hello() {
      echo 'Hi!';
   }
}  =20
echo is_array(new MyArray())  // outputs: true
   ? 'true'=20
   : 'false'; =20

Also, when the object is used by any of the internal PHP functions that =
expect an array, such as sort() the internal function would treat the =
object as an array inside the function.  This also means returning the =
object from methods like array_filter() when an ArrayObject with =
__AsArray()=3D=3D=3Dtrue is passed.

Even though these objects would be treated as arrays when in an array =
context they should still be able to call their own methods, e.g.

$array =3D new MyArray()
$array->hello()  // outputs: Hi!
   ? 'true'=20
   : 'false'; =20

This would go a long way to allowing PHP developers to incrementally =
clean up the gobs of legacy code in the wild, and move to objects where =
appropriate.

-Mike=

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