gistfile1.txt

(defclass checker ()
  ((x :accessor checker-x
      :initarg :x)
   (y :accessor checker-y
      :initarg :y)
   (color :accessor checker-color
          :initarg :color)
   (king :accessor checker-king
         :initarg :king
         :initform nil)))

(defmethod checker-info ((checker checker))
  (format t "x:~a, y:~a, color:~a, king:~a~%"
    (checker-x checker)
    (checker-y checker)
    (checker-color checker)
    (checker-king checker)))

(defvar *checker-0* (make-instance 'checker :x 0 :y 0 :color :red))
(defvar *checker-1* (make-instance 'checker :x 0 :y 0 :color :black))