anchor.diff:  (defmethod setup-default ((minibuffer minibuffer))
     (erase-document minibuffer)
     (setf (input-buffer minibuffer) "")
  -  (setf (input-buffer-cursor minibuffer) 0)
  +  (setf (input-cursor-position minibuffer) 0)
     (setf (content minibuffer)
           (cl-markup:markup
            (:head (:style (minibuffer-style minibuffer))
  
positive.code:    ;; TODO: Move input-* slots to a separate text class?
     (input-prompt :initarg :input-prompt :accessor input-prompt :initform "Input:")
     (input-buffer :accessor input-buffer :initform "")
     ;; cursor position ?
     (input-buffer-cursor :accessor input-buffer-cursor :initform 0)
     (invisible-input-p :initarg :invisible-input-p :accessor invisible-input-p
                        :initform nil
                        :documentation "If non-nil, input is replaced by
  
negative.code: 
  (define-command delete-backwards-word (&optional (minibuffer (current-minibuffer)))
    "Delete characters from cursor position until the beginning of the word at point."
    (with-accessors ((buffer input-buffer) (cursor input-cursor-position)) minibuffer
      (multiple-value-bind (new-string new-position) (%delete-backwards-word buffer cursor)
        (setf buffer new-string
              cursor new-position)))
  