I was reading through some of the Zend framework's hydration source code and came across something I haven't encountered before:
public function hydrate(string $name, ?array $data = null) : string
I've never seen something type hinted like the $data parameter - ?array
I don't know what to search for, so finding documentation on the syntax used there is really difficult. Does anyone know what it is called when you type hint with a question mark like that, and possibly what it does?
Even if you only point me at the right documentation I'd really appreciate any help.
