Variable references in lisp

Question

Another newbie (Common) LISP question:

Basically in most programming languages there\'s a mean for functions to receive references to variables instead of just value

Answer 1

You can produce similar effect by using return values, this is a possible design pattern in Lisp, even though it is not passing a variable by reference.

Like this:

(defun increase (subject increment)
  (+ subject increment))

(let ((my-var 0))
  (message "Initial value: %s" my-var)
  (setq my-var (increase my-var 25))
  (message "Final value: %s" my-var))