anchor.diff:  (defmethod provided-systems ((system system))
     (list system))
   
  -(defmethod initialize-indexes ((dist dist))
  +(defmethod initialize-release-index ((dist dist))
  +  (let ((releases (ensure-release-index-file dist))
  +        (index (release-index dist)))
  +    (call-for-each-index-entry
  +     releases
  +     (lambda (line)
  +       (let ((instance (make-line-instance line 'release
  +                                           :project-name
  +                                           :archive-url
  +                                           :archive-size
  +                                           :archive-md5
  +                                           :archive-content-sha1
  +                                           :prefix
  +                                           :system-files)))
  +         ;; Don't clobber anything previously loaded via CDB
  +         (unless (gethash (project-name instance) index)
  +           (setf (dist instance) dist)
  +           (setf (archive-size instance)
  +                 (parse-integer (archive-size instance)))
  +           (setf (gethash (project-name instance) index) instance)))))
  +    (setf (release-index dist) index)))
  +
  +(defmethod initialize-system-index ((dist dist))
  +  (initialize-release-index dist)
     (let ((systems (ensure-system-index-file dist))
  -        (index (make-hash-table :test 'equal)))
  +        (index (system-index dist)))
       (call-for-each-index-entry
        systems
        (lambda (line)
  
positive.code:    if necessary."))
  
  
  (defgeneric initialize-indexes (dist)
    (:documentation
     "Initialize the system and release indexes of DIST."))
  
  
  (defgeneric local-archive-file (release)
  
negative.code: 
  (defmethod slot-unbound (class (dist dist) (slot (eql 'provided-systems)))
    (declare (ignore class))
    (initialize-system-index dist)
    (setf (slot-value dist 'provided-systems)
          (loop for system being each hash-value of (system-index dist)
                collect system)))
  
  (defmethod slot-unbound (class (dist dist) (slot (eql 'provided-releases)))
    (declare (ignore class))
    (initialize-release-index dist)
    (setf (slot-value dist 'provided-releases)
          (loop for system being each hash-value of (release-index dist)
                collect system)))
  