PHP class declaration

Question

Is there any way to set explicit type to object field in php? Something like this

class House{
       private Roof $roof
}

Answer 1

Nope, there isn't. PHP variables can always be of any type. But you can enforce a type in the setter:

public function setRoof(Roof $roof) {
  $this->roof = $roof;
}

Answer 2

You can't use PHP code to declare the type of an object field.

But you can put type hints in docblock comments:

class House{
       /**
        * @var Roof
        */
       private $roof
}

This still doesn't make the code enforce types, but some IDE tools understand the docblocks and may warn you if you use this variable without conforming to the type hint.