anchor.diff:    (maphash (lambda (k v)
                (declare (ignore k))
                (teardown-frame v))
  -           *frame-display-map*))
  +           *display-frame-map*))
   
   (defun redraw-frame (frame)
     (redraw-display* frame))
  
positive.code: (in-package :lem)
  
  (defparameter *frame-display-map* (make-hash-table))
  
  (defstruct frame
    ;; window
  
negative.code:   (minibuffer-start-charpos nil))
  
  (defun map-frame (key frame)
    (setf (gethash key *display-frame-map*) frame))
  
  (defun get-frame (key)
    (gethash key *display-frame-map*))
  
  (defun current-frame ()
    (get-frame (implementation)))
  
  (defun unmap-frame (key)
    (let ((frame (gethash key *display-frame-map*)))
      (remhash key)
      frame))
  
  