(defun update-indexes (class)
;; Update class and slot indexes.
(when (fboundp 'current-rucksack)
;; This function is also called during compilation of Rucksack
;; (when the class definition of PERSISTENT-OBJECT is compiled).
;; At that stage the CURRENT-RUCKSACK function isn't even defined
;; yet, so we shouldn't call it.
(let ((rucksack (current-rucksack)))
(when rucksack
(rucksack-update-class-index rucksack class)
(rucksack-update-slot-indexes rucksack class)))))