Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:105137
MIME-Version: 1.0
References: <CAC5V6gh79y-i1cQ-XhDBiZTq5BNLDbpcHxNX22mXtYKYrCC94g@mail.gmail.com>
 <CA+kxMuSugdWVPC7Kg-aZb_+24tG-FQ76zbe=psoDC6VfFwcZhA@mail.gmail.com>
In-Reply-To: <CA+kxMuSugdWVPC7Kg-aZb_+24tG-FQ76zbe=psoDC6VfFwcZhA@mail.gmail.com>
Date: Mon, 8 Apr 2019 02:05:07 -0300
Message-ID: <CAEsg9X2ne8w8TKHA-LNb-d3=GTt1tJAEvqiURKbynb4OAmKnew@mail.gmail.com>
To: Dan Ackroyd <Danack@basereality.com>
Cc: Guilliam Xavier <guilliam.xavier@gmail.com>, PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000060b0be0585fdc878"
Subject: Re: [PHP-DEV] [RFC] Nullable Casting
From: david.proweb@gmail.com (David Rodrigues)

--00000000000060b0be0585fdc878
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Real world example:

class Paginator {
    // If null, will use the default value (eg. 15), else, it will requires
an int.
    public function setItemsPerPage(?int $itemsPerPage) { ... }
}

// Info that came from user input.
// It will be a string, and not a integer, like we need.
$itemsPerPage =3D Input::get('itemsPerPage');

// If '<empty>' then $itemsPerPage =3D string '<empty>'
// If '123' then $itemsPerPage =3D string '123'

$paginator->setItemsPerPage($itemsPerPage); // Error: expected int, got
string.

Current solution:

$itemsPerPage =3D Input::get('itemsPerPage') ?: null;
$itemsPerPage =3D $itemsPerPage !=3D=3D null ? (int) $itemsPerPage : null;

$paginator->setItemsPerPage($itemsPerPage); // OK

With this new feature: just...

$paginator->setItemsPerPage((?int) Input::get('itemsPerPage')); // OK

Question: why just not check if $itemsPerPage is set like:

$itemsPerPage =3D Input::get('itemsPerPage');

if ($itemsPerPage) {
    $paginator->setItemsPerPage((int) $itemsPerPage); // OK
}

Answer: because in this example we could do that (although the new solution
is much more practical). In another case, I have a static factory method
that depends of an ?int to be created, and I can't just skip it with an
if() if user input is empty.

And about "settype($variable, "?int")" it was requested on original mailing
by Claude Pache.


Em dom, 7 de abr de 2019 =C3=A0s 23:54, Dan Ackroyd <Danack@basereality.com=
>
escreveu:

> On Sat, 6 Apr 2019 at 08:53, Guilliam Xavier <guilliam.xavier@gmail.com>
> wrote:
> >
> > Hello internals,
> >
> > David and I would like to open the discussion on our joint RFC:
> >
> > https://wiki.php.net/rfc/nullable-casting
> >
> > Mainly, it would enable to use e.g. `(?int)$x` besides `(int)$x`.
> >
>
> I'm guessing you don't actually have ths function getIntOrNull() in
> your code-base? To help me understand where this would be useful,
> could you provide some 'real-world' code where this would be useful?
>
> By the way, this RFC is a special case of something that could be far
> more generic. If it was possible to register callbacks to be used when
> casting, people could do something like this:
>
> function castToIntOrNull($value)
> {
>     if ($value =3D=3D=3D null) {
>         return null;
>     }
>
>     return (int)$int;
> }
>
> register_cast_function('?int', 'castToIntOrNull');
>
> $x =3D (?int)getIntOrNull();
>
>
> > Additionally, it was requested on the mailing list to consider adding
> > support of nullable types to the settype() function,
> > e.g. settype($variable, "?int")
>
> Someone probably needs to make an argument for it to be in core,
> rather than just saying that it's something that could be done.
>
> cheers
> Dan
> Ack
>


--=20
David Rodrigues

--00000000000060b0be0585fdc878--