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

While Common Lisp supports a functional programming style, that is not its general focus (Scheme, while not purely functional, is much closer). Common Lisp supports a completely imperative style of programming very well.

If you find you need to write code like that, the usual solution is a macro:

(defmacro increase-by-one (var)
  `(setf ,var (+ ,var 1)))

This allows you to write code like:

(increase-by-one foo)

which will be expanded into:

(setf foo (+ foo 1))

before it is compiled.