call-next-method復習

call-next-method.lisp

(defclass parent () ())
(defclass child (parent) ())
(defparameter p1 (make-instance 'parent))
(defparameter c1 (make-instance 'child))

(defgeneric say (self word))

(defmethod say ((self parent) word)
  (format t "~A says ~A~%" self word))

(defmethod say ((self child) word)
  (format t "In child. ")
  (call-next-method))

(say p1 "hoge") ; => #<PARENT {1006518C23}> says hoge
(say c1 "mage") ; => In child. #<CHILD {1006528C23}> says mage

(defmethod say ((self child) word)
  (format t "In child. ")
  (call-next-method self (string-upcase word)))

(say p1 "hoge") ; => #<PARENT {1006518C23}> says hoge
(say c1 "mage") ; => In child. #<CHILD {1006528C23}> says MAGE