anchor.diff:            (move-mark point)
             (move-end-of-line buffer))
         (unwind-protect
  -           (delete-region buffer here point)
  +           (kill-region buffer here point)
           (point-to-mark buffer here))))
     (values))
   
  
positive.code:   "Insert STRING into BUFFER at point. STRING is a string-designator, so can be a character."
    (loop for ch across (string string)
       if (char= ch #\Newline)
       do (insert-line buffer)
       else do (insert-char buffer ch)))
  
  (defun order-marks (mark-1 mark-2)
    (let ((line-1 (mark-line mark-1))
  
negative.code:     ;; Link into the line list.
      (cond ((next-line current-line)
             (setf (previous-line (next-line current-line)) new-line))
            ((line-buffer current-line)
             (setf (last-line (line-buffer current-line)) new-line)))
      (setf (next-line current-line) new-line)
      ;; Ensure coherent numbering.
      (cond ((and (next-line new-line)
  