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 = Input::get('itemsPerPage');
// If '<empty>' then $itemsPerPage = string '<empty>'
// If '123' then $itemsPerPage = string '123'
$paginator->setItemsPerPage($itemsPerPage); // Error: expected int, got
string.
Current solution:
$itemsPerPage = Input::get('itemsPerPage') ?: null;
$itemsPerPage = $itemsPerPage !== 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:
$itemsPerPage = Input::get('itemsPerPage');
if ($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 às 23:54, Dan Ackroyd <dan...@basereality.com>
escreveu:
> On Sat, 6 Apr 2019 at 08:53, Guilliam Xavier <guilliam.xav...@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 === null) {
> return null;
> }
>
> return (int)$int;
> }
>
> register_cast_function('?int', 'castToIntOrNull');
>
> $x = (?int)getIntOrNull();
>
>
> > Additionally, it was requested on the mailing list to consider adding
> > support of nullable types to the settype() function,
> > e.g. settype($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
>
--
David Rodrigues
