;;; with default optimizations
(defun factorial (n)
  (cond ((= n 0) 1)
    (t (* n (factorial (- n 1))))))


;;; poor, c conversion, :)
#+:clisp
(format t "~S~&" (factorial 6000))

;;; better, :)
#+:ecl
(format t "~S~&" (factorial 12000))

;;; this is already optimized by default
#+:cmu
(format t "~S~&" (factorial 100000))

;;; the numbers are random, that means i didn't try to find a limit,
;;; just stop before 'stack overflow' for clisp and ecl, first hit
;;; from cmucl
;;;
;;; usage, just (load "fact.lisp") in the interpretor.
;;;