anchor.diff:                       (decf (buffer-undo-node buffer))
                        (buffer-undo-modified buffer))
                       (t
  +                     (assert (eq :separator (car (buffer-redo-stack buffer))))
  +                     (pop (buffer-redo-stack buffer))
                        (minibuf-print "Undo Error")))
                 pres))))
   
  
positive.code:                      (incf (buffer-undo-node buffer))
                       (buffer-undo-modified buffer))
                      (t
                       (minibuf-print "Redo Error")))
                pres))))
  
  
negative.code:           (funcall elt))))))
  
  (defun buffer-undo (buffer)
    (push :separator (buffer-redo-stack buffer))
    (prog1 (do ((res #1=(buffer-undo-1 buffer) #1#)
                (pres nil res))
  