One of the characteristic of PHP is that it doesn’t do strong typing.

PHP 5.1 introduced Type Hinting. Functions were able to force parameters to be objects (by specifying the name of the class in the function prototype) or arrays.

I recently read one RFC (Request For Comments) - on PHP.net wiki - from Felipe Peruna about Return value and parameter type hint. Basically, the idea is to allow to specify what will be the type of the result of a function or method. Here is an example.

<?php 

class test {
    public function (int) foo(){
        // ...
    }
}

In that previous example, the method foo must return an integer, if that’s not the case, then the following error will be triggered : “Catchable fatal error: The returned value must be of the type integer”.

I personally think this could come handy in some cases.