anchor.diff:                           default-attribute)
       (charms/ll:wnoutrefresh scrwin)))
   
  -(define-interface redraw-display-window (window force)
  +(define-implementation redraw-display-window (window force)
     (when (eq window (current-window)) (window-see window))
     (lem::window-prompt-display window)
     (progn
  
positive.code: (defun display-finalize ()
    (term-finalize))
  
  (define-interface display-width () charms/ll:*cols*)
  (define-interface display-height () charms/ll:*lines*)
  
  (define-interface call-with-screen (function)
    (unwind-protect (progn
                      (display-init)
                      (funcall function))
  
negative.code:                 :lines (make-array (max 0 height) :initial-element nil)
                  :old-lines (make-array (max 0 height) :initial-element nil)))
  
  (define-implementation screen-delete (screen)
    (charms/ll:delwin (screen-%scrwin screen))
    (when (screen-%modeline-scrwin screen)
      (charms/ll:delwin (screen-%modeline-scrwin screen))))
  
  (define-implementation screen-clear (screen)
    (screen-modify screen)
    (charms/ll:clearok (screen-%scrwin screen) 1)
    (when (screen-%modeline-scrwin screen)
      (charms/ll:clearok (screen-%modeline-scrwin screen) 1)))
  
  (define-implementation screen-erase (screen)
    (charms/ll:werase (screen-%scrwin screen)))
  
  (defun screen-height (screen)
    (length (screen-lines screen)))
  
  (define-implementation screen-modify (screen)
    (setf (screen-modified-p screen) t))
  
  (define-implementation screen-set-size (screen width height)
    (screen-modify screen)
    (when (screen-%modeline-scrwin screen)
      (decf height))
  