Method: (RUCKSACK-MAP-CLASS STANDARD-RUCKSACK T T)

Source

(defmethod rucksack-map-class ((rucksack standard-rucksack) class function
                               &key (id-only nil) (include-subclasses t))
  ;; EFFICIENCY: Follow Sean Ross' suggestion and implement ID-ONLY
  ;; by defining a function MAP-INDEX-KEYS and then calling
  ;; that function here (so that we don't need to load any objects
  ;; that we don't want to load yet).
  (let ((visited-p (make-hash-table)))
    (labels ((map-instances (class)
               (let ((index (rucksack-class-index rucksack class :errorp nil)))
                 (when index
                   (map-index index
                              (lambda (id object)
                                (if id-only
                                    (funcall function id)
                                  (funcall function object))))
                   (setf (gethash class visited-p) t))
                 (when include-subclasses
                   (loop for class in (class-direct-subclasses
                                       (if (symbolp class)
                                           (find-class class)
                                         class))
                         unless (gethash class visited-p)
                         do (map-instances class))))))
      (map-instances class))))