defmethod without classes

defmethod.lisp

#!/usr/bin/sbcl --script

;;
;; You don't really need to supply a class literal to use methods,
;; this way you can exploid the :before, :after, :around auxiliary 
;; methods!
;;

(defmethod myfunc (lst)
  (format t "~A~%" lst))

(defmethod myfunc :before (lst)
  (format t "Y HALLO THERE~%"))

(defmethod myfunc :after (lst)
  (format t "Interesting thing you saw~%"))

(defmethod i-never-run (lst)
  (format t "and i feel terrible about it. I need to become fit again~%"))

(defmethod i-never-run :around (lst)
  (format t "~A~A~%" "i run everyday every week every month every year. "
            "Check out my massive legs!"))

(myfunc '(1 2 3 4 5))

(i-never-run '(1 2 3))

;; Output
;;
;; Y HALLO THERE
;; (1 2 3 4 5)
;; Interesting thing you saw
;; i run everyday every week every month every year. Check out my massive legs!