Question

I would like to create a nil function that takes any number of symbols and sets them all to nil.

(defun clean (as many args as given by user)
  (setq each-arg nil)
)

(clean x y z)

How to do this ‘cleanly’?

Answer 1

Since you’re not quoting the arguments, it has to be a macro:

(defmacro clean (&rest symbols)
  `(progn
     ,@(mapcar (lambda (sym) (list 'setq sym 'nil))
               symbols)))