anchor.diff:    (move-mark-to-mark mark (buffer-point buffer)))
   
   (defun mark-at-point-p (buffer mark)
  -  (mark-equal-p mark (buffer-point buffer)))
  +  (mark= mark (buffer-point buffer)))
   
   (defun start-of-line-p (mark)
     (eql (mark-charpos mark) 0))
  
positive.code:           ;; and the new position.
            ;; FIXME: This will cause a bunch of lines to be redrawn when the point & mark are exchanged.
            (when (and (buffer-mark-active buffer)
                       (not (mark-equal-p point previous-point-position)))
              (flush-display-lines-in-region point previous-point-position))
            ;; If the mark is or was active and moves, flush lines between the old mark position
            ;; and the new position.
            ;; FIXME: This will cause a bunch of lines to be redrawn when the point & mark are exchanged.
            (when (and (or (buffer-mark-active buffer)
                           (buffer-property buffer 'pane-mark-was-active))
                       (not (mark-equal-p mark previous-mark-position)))
              (flush-display-lines-in-region mark previous-mark-position))
            ;; Finally, flush any stale lines.
            (flush-stale-lines)
  
negative.code: (defvar *this-command*)
  (defvar *last-character*)
  (defvar *this-character*)
  (defvar *minibuffer*)
  (defvar *minibuffer-key-map*)
  
  (defvar *editor*)
  
  (defgeneric dispatch-event (editor event)
  