Newsgroups: php.internals
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Xref: news.php.net php.internals:120655
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Date: Thu, 22 Jun 2023 01:44:25 +0300
Message-ID: <CAPyeZ4OmR8CBfh5VSz6YOhzN6gdkYwBMGak89HyyNQinqDx8eA@mail.gmail.com>
To: internals@lists.php.net
Content-Type: multipart/alternative; boundary="00000000000019d7bf05feab83a0"
Subject: [Proposal] Introduce is operator
From: udaltsov.valentin@gmail.com (=?UTF-8?B?0KPQtNCw0LvRjNGG0L7QsiDQktCw0LvQtdC90YLQuNC9?=)

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Hi internals,

Today PHP is more typed than ever, however, one feature is still missing:
ability to check complex variable types using standard type declarations.

For example, to check that $var is a nullable string one has to do
`assert($var === null || is_string($var))`. To check that $var is false or
a countable iterator, one has to write `assert($var === false || ($var
instanceof Countable && $var instanceof Iterator))`.

I propose to add a new "is" operator that allows to have `assert($var is
?string)` and `assert($var is false|(Countable&Iterator))`. So it is
similar to instanceof, but accepts any valid PHP type declaration on the
right side.

WDYT?

Regards,
Valentin

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