anchor.diff:      (values dest source dest)))
   
   (defgeneric file-write-date-using-host (host path))
  +(defmethod file-write-date-using-host (host path)
  +  nil)
   
   (defun file-write-date (pathspec)
     (let ((path (translate-logical-pathname (merge-pathnames pathspec))))
  
positive.code:            #:ensure-directories-exist-using-host
             #:rename-file-using-host
             #:file-write-date-using-host
             #:delete-file-using-host
             #:expunge-directory-using-host
             #:file-stream-pathname
  
negative.code:     (file-write-date-using-host (pathname-host path) path)))
  
  (defgeneric file-author-using-host (host path))
  (defmethod file-author-using-host (host path)
    nil)
  
  (defun file-author (pathspec)
    (let ((path (translate-logical-pathname (merge-pathnames pathspec))))
  