It is worth noting that you can use functions as function arguments
<?php
function run($op, $a, $b) {
return $op($a, $b);
}
$add = function($a, $b) {
return $a + $b;
};
$mul = function($a, $b) {
return $a * $b;
};
echo run($add, 1, 2), "\n";
echo run($mul, 1, 2);
?>
Output:
3
2