;  File:    shapes.l
;  date:    09/22/99
;  type:    pcl (clos)
;  author:  kathi dutton

;  eloboration:  
;     A progam which creates an object, specifically a rectangle.  The
;     rectangle can then be displayed.  As well as calculating its area
;     and perimeter.

;--------------------------------------------------------------------
;  enter clos

  ( in-package "pcl" )

;--------------------------------------------------------------------
;  Define a shapes class

  ( defclass shapes ()
    ( 
      ( base :accessor shapes-base :initarg :base )
      ( height :accessor shapes-height :initarg :height )
    )
  )

;--------------------------------------------------------------------
;   Define a display method

  ( defmethod display ( ( r shapes ) )
    ( princ "(" )
    ( princ ( shapes-base r ) )
    ( princ "," )
    ( princ ( shapes-height r ) ) 
    ( princ ")" )
    ( terpri )
  )

;-------------------------------------------------------------------
;  make an instance of a rectangle

  ( defmethod rect ( base height )
    ( setf *shaprect*
        ( make-instance 'shapes :base base :height height )
    )
  )

;------------------------------------------------------------------
;  Define method to calculate rectangle's area

  ( defmethod area ()
    ( setf base ( shapes-base *shaprect* ) )
    ( setf height ( shapes-height *shaprect* ) )
      ( setf result (* base height)) 
      ( princ "area " ) ( prin1 result ) ( terpri )
    )
  )

;-------------------------------------------------------------------
;  Define method to calculate rectangle's perimeter

  ( defmethod perimeter ()
      ( setf base ( shapes-base *shaprect* ) )
      ( setf height ( shapes-height *shaprect* ) )
        ( setf result ( + ( * 2 base ) ( * 2 height ) ) )
        ( princ "perimeter " ) ( prin1 result ) ( terpri )
    ) 
  )