The code pre-dates Pascal Costanza's closer-mop package. If you're looking for a compatability layer you should probably look there instead.
(define-method-combination wrapping-standard (&key (around-order :most-specific-first) (before-order :most-specific-first) (primary-order :most-specific-first) (after-order :most-specific-last) (wrapping-order :most-specific-last) (wrap-around-order :most-specific-last)) ((wrap-around (:wrap-around)) (around (:around)) (before (:before)) (wrapping (:wrapping)) (primary () :required t) (after (:after))) "Same semantics as standard method combination but allows \"wrapping\" methods. Ordering of methods: (wrap-around (around (before) (wrapping (primary)) (after))) :warp-around, :around, :wrapping and :primary methods call the next least/most specific method via call-next-method (as in standard method combination). The various WHATEVER-order keyword arguments set the order in which the methods are called and be set to either :most-specific-last or :most-specific-first." (labels ((effective-order (methods order) (ecase order (:most-specific-first methods) (:most-specific-last (reverse methods)))) (call-methods (methods) (mapcar (lambda (meth) `(call-method ,meth)) methods))) (let* (;; reorder the methods based on the -order arguments (wrap-around (effective-order wrap-around wrap-around-order)) (around (effective-order around around-order)) (wrapping (effective-order wrapping wrapping-order)) (before (effective-order before before-order)) (primary (effective-order primary primary-order)) (after (effective-order after after-order)) ;; inital value of the effective call is a call its primary ;; method(s) (form (case (length primary) (1 `(call-method ,(first primary))) (t `(call-method ,(first primary) ,(rest primary)))))) (when wrapping ;; wrap form in call to the wrapping methods (setf form `(call-method ,(first wrapping) (,@(rest wrapping) (make-method ,form))))) (when before ;; wrap FORM in calls to its before methods (setf form `(progn ,@(call-methods before) ,form))) (when after ;; wrap FORM in calls to its after methods (setf form `(multiple-value-prog1 ,form ,@(call-methods after)))) (when around ;; wrap FORM in calls to its around methods (setf form `(call-method ,(first around) (,@(rest around) (make-method ,form))))) (when wrap-around (setf form `(call-method ,(first wrap-around) (,@(rest wrap-around) (make-method ,form))))) form)))