;; (when 1 (breakpoint))

;; (if (eval 1)
;;     (apply prog ((breakpoint)))
;;   nil))

;; (if (eval 1)
;;     (eval (pair prog ((breakpoint)))))
;;   nil))


(defun ! (n)
  (if (< n 2)
      1
    (* n (! (- 1 n)))))