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Date: Wed, 5 Oct 2022 20:01:19 +0200
Message-ID: <CADyq6sLd-U8cWvQNe3PzdoYwxuGaHOz0tsCRc6fZnowDDq19tQ@mail.gmail.com>
To: Eugene Sidelnyk <zsidelnik@gmail.com>
Cc: juan carlos morales <dev.juan.morales@gmail.com>, Claude Pache <claude.pache@gmail.com>, 
	PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Union type casts
From: ocramius@gmail.com (Marco Pivetta)

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On Wed, 5 Oct 2022 at 19:53, Eugene Sidelnyk <zsidelnik@gmail.com> wrote:

> I used to have an awkward feeling when it was necessary to convert the
> nullable integer into a nullable string. It would be kind of ternary
> operator anyway. Either `$b = (null !== $a) ? (string)$a : null;` or `$b =
> (string)$a ?: null;`.
>
> A lot easier to read would it be if written this way: `$b = (?string)$a;`.
> The intentions are clear when doing explicit type-cast.
>
> Currently, I don't see any other situations when this feature may be useful
>

I don't think that this tiny edge case warrants a new language feature.

I can endorse using [`azjezz/psl`](
https://github.com/azjezz/psl/blob/34391b78f097e7d489bd618d2cb15ef474937896/src/Psl/Type/TypeInterface.php#L21-L26)
for this though:

```php
use Psl\Type;

$myValue = Type\union(Type\int(), Type\null())
    ->coerce($input);
```

This will also throw an exception (**GOOD**) if the cast is not safe to
perform.

Marco Pivetta

https://twitter.com/Ocramius

https://ocramius.github.io/

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