[cr33pyguy]

Well, $this is referring to the parent class, -> is used for referencing variables and functions within the class.

For example, in the code above, I have the variable/array called $cart, I'm giving the variable $potato the value stored in the $cart variable.

PHP Code:

$potato = $this->cart;

For some better explanations, I suggest checking out their documentation.

Okay, so it's practically saying $potato is it's value in the array $cart?