calling-a-private-method-using-a-closure.php

<?php

class AnswerAdder
{
    private function addTheAnswer($x)
    {
        return 42 + $x;
    }
}

$callPrivateMethod = function ($object, $method, ...$args) {
    $call = function ($method, ...$args) {
        return $this->$method(...$args);
    };
    $newCall = $call->bindTo($object, get_class($object));
    return $newCall($method, ...$args);
};

echo $callPrivateMethod(new AnswerAdder(), 'addTheAnswer', 1);