oop - Is it possible to write strictly typed PHP code?

Question

For example, is it possible to write code like this:

int $x = 6;
str $y = "hello world";
bool $z = false;
MyObject $foo = new MyObject();

And is it possible to define functions like this:

public int function getBalance()
{
   return 555; //Or any numeric value
}

Answer 1

In PHP 7 are implemented "Scalar Type Declarations", e.g.:

public function getBalance(): int {
    return 555;
}

You need to declare, that you will use strict types:

<?php
    declare(strict_types=1);

    function sum(int $a, int $b): int {
        return $a + $b;
    }

    sum(1, 2);
?>

More information: https://wiki.php.net/rfc/scalar_type_hints_v5