;; the following illustrates the definition of CLOS classes for use in
;;      the system.  Note that the classes are subordinates of the
;;      previously defined RBR-object class.
;   note new function defRBRclass should be used here when written

(defclass train (RBR-object)
        ((place :accessor place :initarg :place :initform 'unknown)
         (in-motion     :accessor in-motion :initarg :in-motion
                        :initform 'unknown)))

(defclass signal (RBR-object)
        ((place :initform 'unknown :initarg :place :accessor place )
         (color :initform 'unknown :initarg :color :accessor color )))


;; one can have a file of such calls and simple load it or evaluate
;;      a set of selected instances directly.  Alternatively, one
;;      can setf a list of such calls to a name, then mapcar #'eval
;;      over that list.  It would be useful to write a top level function
;;      to do that.  The following illustrates a temporary function that
;;      is useful for developing the system.


(defun test-setup (OB)
  (clear-RBR)
  (mapcar #'eval OB))


(setf testOB '(
(make-RBR-instance 'train
        :place 4
        :in-motion 'yes
        :name 1 )               ;note slot and accessor inherited from RBR-object

(make-RBR-instance 'train
        :place 5
        :in-motion 'no
        :name 2)

(make-RBR-instance 'train
        :place 2
        :in-motion 'yes
        :name 3)

(make-RBR-instance 'signal
        :place 5
        :color 'green
        :name 1 )               ;no confusion re name conflict,
                                ;this is an object of different type

(make-RBR-instance 'signal
        :place 8
        :color 'red
        :name 2 )

(make-RBR-instance 'signal
        :place 3
        :color 'green
        :name 3 )

))

;; Note the distinction between this and *RB*.  Each expression here is
;;      a function call to make-RBR-instance, where as each rule in
;;      *RB* is just a list structure.  The calls to make-RBR-instance
;;      push the created CLOS instances onto a list which is the
;;      value of *OB*.  The rules could be handled in a similar way,
;;      with the various parts of each rule placed on slots of a CLOS
;;      class defined for that purpose.

;; the following sets *OB* using the temporary setup function defined
;;      above.

(test-setup testOB)