initialising interdependent variables inside the defsketch macro about sketch HOT 9 CLOSED

(b (print (change-state a)))

(PROGN
 (DEFCLASS NIER (SKETCH)
           ((A :INITARG :A :ACCESSOR NIER-A) (B :INITARG :B :ACCESSOR NIER-B)))
 (DEFMETHOD PREPARE PROGN
            ((INSTANCE NIER) &REST INITARGS &KEY &ALLOW-OTHER-KEYS)
   (DECLARE (IGNORABLE INITARGS))
   (LET* ((FULLSCREEN (SLOT-VALUE INSTANCE 'FULLSCREEN))
          (COPY-PIXELS (SLOT-VALUE INSTANCE 'COPY-PIXELS))
          (Y-AXIS (SLOT-VALUE INSTANCE 'Y-AXIS))
          (TITLE
           (IF (GETF INITARGS :TITLE)
               (SLOT-VALUE INSTANCE 'TITLE)
               "weir"))
          (WIDTH
           (IF (GETF INITARGS :WIDTH)
               (SLOT-VALUE INSTANCE 'WIDTH)
               1000))
          (A (OR (GETF INITARGS :A) (MAKE-HASH-TABLE :TEST #'EQUAL)))
          (B (OR (GETF INITARGS :B) (CHANGE-STATE A)))
          (HEIGHT
           (IF (GETF INITARGS :HEIGHT)
               (SLOT-VALUE INSTANCE 'HEIGHT)
               1000)))
     (DECLARE
      (IGNORABLE TITLE WIDTH HEIGHT FULLSCREEN COPY-PIXELS Y-AXIS TITLE WIDTH A
       B HEIGHT))
     (SETF (SKETCH-TITLE INSTANCE) TITLE
           (SKETCH-WIDTH INSTANCE) WIDTH
           (SKETCH-HEIGHT INSTANCE) HEIGHT
           (SKETCH-FULLSCREEN INSTANCE) FULLSCREEN
           (SKETCH-COPY-PIXELS INSTANCE) COPY-PIXELS
           (SKETCH-Y-AXIS INSTANCE) Y-AXIS)
     ; replace this ------------------------------------
     ;(SETF (SLOT-VALUE INSTANCE 'A) (MAKE-HASH-TABLE :TEST #'EQUAL)
     ;      (SLOT-VALUE INSTANCE 'B) (CHANGE-STATE A))
     ; with this? ----------------------------------------
     (SETF (SLOT-VALUE INSTANCE 'A) A
           (SLOT-VALUE INSTANCE 'B) B))
   (SETF (ENV-Y-AXIS-SGN (SLOT-VALUE INSTANCE '%ENV))
           (IF (EQ (SLOT-VALUE INSTANCE 'Y-AXIS) :DOWN)
               1
               -1)))
 (DEFMETHOD DRAW ((INSTANCE NIER) &KEY &ALLOW-OTHER-KEYS)
   (WITH-ACCESSORS ((TITLE SKETCH-TITLE) (WIDTH SKETCH-WIDTH)
                    (HEIGHT SKETCH-HEIGHT) (FULLSCREEN SKETCH-FULLSCREEN)
                    (COPY-PIXELS SKETCH-COPY-PIXELS) (Y-AXIS SKETCH-Y-AXIS))
       INSTANCE
     (WITH-SLOTS (TITLE WIDTH A B HEIGHT)
         INSTANCE
       (PRINT (LIST :A (GETHASH 'V A) :B (GETHASH 'V B)))
       (BACKGROUND (GRAY 0.1)))))
 (MAKE-INSTANCES-OBSOLETE 'NIER)
 (FIND-CLASS 'NIER))

(SETF (SLOT-VALUE SKETCH::INSTANCE 'CELL-SIZE) (10)
           (SLOT-VALUE SKETCH::INSTANCE 'POS-VEC)
             ((MAKE-VEC2 :X (/ WIDTH 2) :Y (/ HEIGHT 2)))
           (SLOT-VALUE SKETCH::INSTANCE 'RUNNING) (T))