anchor.diff:              ((eql e :timeout)
                (assert timeout)
                (return nil))
  -            ((and (consp e) (eq +resize-screen+ (car e)))
  -             (destructuring-bind (width height) (cdr e)
  -               (update-display-size width height)))
               (t
                (return e))))))
   
  
positive.code: 
  (defun empty-queue-p (queue)
    (null (car queue)))
  
  (defparameter +resize-screen+ (make-symbol "RESIZE-SCREEN"))
  
  (let ((wait (bt:make-condition-variable))
        (lock (bt:make-lock))
  
negative.code:   (defun send-event (obj)
      (bt:with-lock-held (lock)
        (enqueue queue obj)
        (bt:condition-notify wait))))
  
  (defun send-abort-event (editor-thread)
    (bt:interrupt-thread editor-thread
                         (lambda ()
                           (error 'editor-interrupt))))
  
  (defun receive-event (timeout)
    (loop
  