;;; -*- mode: emacs-lisp -*-
;;; $Id: ackermann.xemacs,v 1.2 2000/12/07 04:06:18 doug Exp $
;;; http://www.bagley.org/~doug/shootout/

(setq max-lisp-eval-depth 8000)
(setq max-specpdl-size 5000)

(defun Ack (M N)
  (cond ((= M 0) (+ N 1))
	((= N 0) (Ack (- M 1) 1))
	(t (Ack (- M 1) (Ack M (- N 1))))))

(defun main ()
  (let* ((arg (car command-line-args-left))
	 (num (if arg (string-to-number arg) 1)))
    (princ (format "Ack(3,%d): %d\n" num (Ack 3 num)))))