Lisp Methods CLOS

methods.lisp

(defclass book ()
  ((name :accessor book-name
	 :initarg :book-name)))

(defclass door ()
  ((colour :accessor door-colour
	   :initarg :door-colour)))

(defclass window ()
  ((name :accessor window-name
	 :initarg :window-name)))

;; Creating Instances of Classes
(defparameter *book* (make-instance 'book :book-name "The Art of the Metaobject Protocol"))
(defparameter *door* (make-instance 'door :door-colour "white"))
(defparameter *window* (make-instance 'window :window-name "magic window"))

;;; Defining the method open-this of the book class
(defmethod open-this ((object book))
  (format t "Open ... ~a book~%" (book-name object)))

;;; Defining the method close-this of the book class
(defmethod close-this ((object book))
  (format t "~a book was closed ~%" (book-name object)))

;;; Defining the method open-this of the door class
(defmethod open-this ((object door))
  (format t "Open ... the ~a door ~%" (door-colour object)))

;;; Defining the method close-this of the door class
(defmethod close-this ((object door))
  (format t "The ~a door was closed~%" (door-colour object)))

;;; Defining the method open-this of the window class
(defmethod open-this ((object window))
  (format t "Open ... the ~a ~%" (window-name object)))

;;; Defining the method close-this of the window class
(defmethod close-this ((object window))
  (format t "The ~a was closed ~%" (window-name object)))