anchor.diff:     (x :initform 0 :initarg :x-position)
      (y :initform 0 :initarg :y-position)
      (width :initform 8)
  -   (appearance :type (member :solid :hollow) 
  +   (appearance :type (member :solid :hollow)
                  :initarg :appearance :initform :hollow
                  :accessor cursor-appearance)
      ;; XXX what does "cursor is active" mean?
  
positive.code: 			  (+ x width) (+ y height)
  			  :filled (ecase (cursor-appearance cursor)
  				    (:solid t) (:hollow nil))
  			  :ink +foreground-ink+))       
          (:erase
  	 ;; This is how I'd like this to work, as painting over with
  	 ;; the background ink is repugnant. I leave this disabled
  
negative.code:                  ;; Let's prevent infinite recursion if there isn't
                   ;; room for even a single character.
  		 (setq split (max (find-split (- margin cx))
                                    (1+ start))))
  		(:scroll
  		 (scroll-horizontal stream width))
  		(:allow)))
  