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Date: Tue, 24 Mar 2020 14:32:35 +0100
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Subject: Type casting while array destructuring
From: enno.woortmann@web.de (Enno Woortmann)

Hi,

currently when using array destructuring the variables are assigned as
they are. For example we split a string with explode all variables will
contain strings:

$data =3D "foo:*:1023:1000::/home/foo:/bin/sh";
[$user, $pass, $uid, $gid, $gecos, $home, $shell] =3D explode(":", $data);

If we want to write functions consuming $uid and $gid as integer values
with strict types enabled we need to cast the values afterwards:

$uid =3D (int) $uid;
$gid =3D (int) $gid;
// or during the function call
$myConsumingObject->myConsumingFunction((int) $uid, (int) $gid);

I think you get my point. How about adding some syntactic sugar and
allow type casting inside the detructuring expression?

$data =3D "foo:*:1023:1000::/home/foo:/bin/sh";
[$user, $pass, (int) $uid, (int) $gid, $gecos, $home, $shell] =3D
explode(":", $data);
// $uid and $gid are integer values now. All other variables remain as
they are and contain strings

An example with associative arrays in loops:

$array =3D [
 =C2=A0=C2=A0=C2=A0 [
 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 'name' =3D> 'a',
 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 'id' =3D> '1'
 =C2=A0=C2=A0=C2=A0 ],
 =C2=A0=C2=A0=C2=A0 [
 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 'name' =3D> 'b',
 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 'id' =3D> '2'
 =C2=A0=C2=A0=C2=A0 ],
];

foreach ($array as ['id' =3D> (int) $id, 'name' =3D> $name]) {
 =C2=A0=C2=A0=C2=A0 // $id contains integer values
}

Further thoughts: when using the list() reference assignment implemented
in PHP7.3 the referenced value could be casted (something to discuss
about, maybe as future scope as casting a reference assignment currently
isn't supported):

$array =3D [1, 2];
[(string) $a, (string) &$b] =3D $array;
// $a would be a string: '1'
// $b would be a string: '2'
// $array would contain one integer and one string element: [1, '2']

Thoughts?