Rewriting an anonymous function in php 7.4

Question

There is the following anonymous recursive function:

$f = function($n) use (&$f) {
    return ($n == 1) ? 1 : $n * $f($n - 1);
};

echo $f(5); // 120
         


        

Answer 1

I think I just found one of the legitimate (no?) uses of $GLOBALS

$f = fn ($n) =>($n == 1) ? 1 : $n * $GLOBALS['f']($n - 1);
echo $f(5); // 120

Sidenote: what if $n < 1 ?