In a new post to his site Joseph Silber looks at a new feature that will be coming with the next release in the PHP 7.x series - PHP 7.1 - the ability to convert a callable type into an actual Closure instance.

With PHP 5.5 going EOL earlier this week and the PHP 7.1 beta expected later this month, now sounds like a good time to look into a neat little feature coming in 7.1: easily converting any callable into a proper Closure using the new Closure::fromCallable() method.

He starts with a quick refresher on what closures/callables are in PHP (or an introduction for those not already familiar) including a simple example with the reject handling on a Laravel collection. He then modifies the example to try to pass in a base PHP function. This doesn't work directly (as it's not technically "callable" how it's expecting) so he wraps the is_float in a closure instead. This is a bit of a hassle and not as reusable so he updates it for PHP 7.1 and uses the Closure::fromCallable handling to make it automatically. He follows this with another example use case: calling a private method with the array of object/method name from inside the class.