anchor.diff:  
   (defvar *minibuf-window*)
   (defvar *minibuffer-calls-window*)
  -(defvar *minibuffer-start-point*)
  +(defvar *minibuffer-start-charpos*)
   (defvar *minibuffer-prompt-attribute* (make-attribute "blue" nil :bold-p t))
   
   (defun minibuffer-window () *minibuf-window*)
  
positive.code:                                 :read-only t
                                  :field t)
                   (character-offset (current-point) (length prompt)))
                 (with-point ((*minibuffer-start-point* (current-point) :right-inserting))
                   (when initial
                     (insert-string (current-point) initial))
                   (unwind-protect (call-with-save-windows
  
negative.code:       (minibuffer-window)
        nil))
  
  (defun minibuffer-start-point ()
    (character-offset
     (copy-point (buffers-start (minibuffer))
                 :temporary)
     *minibuffer-start-charpos*))
  
  (defun get-minibuffer-string ()
    (points-to-string (minibuffer-start-point)
                      (buffers-end (minibuffer))))
  
  (defun minibuffer-clear-input ()
    (delete-between-points (minibuffer-start-point)
                           (buffers-end (minibuffer))))
  
  (define-command minibuf-read-line-confirm () ()
  