How to get "into the depths" of an object?

Question

PHP

Hi, next question.
There is an object A
There is B that inherits A
, A has a $var variable
and has an add() method
(which, logically, B also has)
When adding() is called, the B object must be written to the very end of the chain in the $var variable I
explain on my fingers: call add () Press again I beg you: 1. do not throw slippers, but I'm a noob 2. Do not spoil the answer. but push towards a solution. I've tried different iteration methods. I can climb into the depths, but I don’t know how to “climb out” or something else Thank you!
А([var]=>)
A([var]=>B([var]=>))
A([var]=>B([var]=>B([var]=>)))

Answer 1

Well, $var is an array, so work with it like an array. All elements match the order in which add is called.

Answer 2

Looks like what you need
php.net/manual/kr/keyword.parent.php