(defun gb-expand-slot-def ()
  (interactive "")
  (let* ((p1 (point))
         (p2 (progn (backward-sexp) (point)))
         (slot (buffer-substring p1 p2))
         (class nil))
    (delete-region p1 p2)
    (save-excursion
      (backward-up-list 2)
      (down-list)
      (forward-sexp)                    ;defclass
      (forward-sexp)                    ;end of class name
      (setf p2 (point))
      (backward-sexp)                   ;start of class name
      (setf p1 (point)))
    (setf class (buffer-substring p1 p2))
    (insert-string "(")
    (insert-string slot)
    (insert-string " :initarg :")
    (insert-string slot)
    (insert-string " :initform nil")
    (insert-string " :accessor ")
    (insert-string class)
    (insert-string "-")
    (insert-string slot)
    (insert-string ")")))