anchor.diff:                     :width width
                      :height height
                      :use-modeline-p nil
  -                   :completion-function (completion-function parameters)
  -                   :existing-test-function (existing-test-function parameters)
  -                   :called-window (called-window parameters))))
  +                   :completion-function (prompt-window-completion-function parameters)
  +                   :existing-test-function (completion-window-existing-test-function parameters)
  +                   :called-window (prompt-window-called-window parameters)
  +                   :history (prompt-window-history parameters))))
   
   (defmethod lem::update-prompt-window ((window prompt-window))
     (destructuring-bind (x y width height)
  
positive.code:                 :when-let))
  (in-package :lem.prompt-window)
  
  (define-condition execute ()
    ((input
      :initarg :input
  
negative.code:                                      (make-instance 'prompt-window-parameters
                                                      :completion-function completion-function
                                                      :existing-test-function existing-test-function
                                                      :called-window called-window
                                                      :history (get-history history-name)))))
      (handler-case
          (with-unwind-setf (((lem::frame-prompt-window (current-frame))
                              prompt-window))
  