anchor.diff:    last-modified
     creation-date
     date
  -  tags
     author
     title
     template
  
positive.code: 	       :date (if-let ((date (get-data :date)))
  		       (make-time date creation-date)
  		       creation-date)
  	       :tags (iter (for (lang tags) on (getf *environment* :tags) by #'cddr)
  			   (collect lang)
  			   (collect (split-comma-or-space-separated (first tags))))
  	       :author (getf *environment* :author)
  	       :title (getf *environment* :title)
  	       :template template
  
negative.code:   "String &keys (lang Keyword) (format (Keyword or String or (Keyword Integer &optional Character))) -> String"
    (format-timestring nil date :format format))
  
  (def-page-accessor page-title content-entry-title title (path lang)
    "String &keys (lang Keyword) -> String"
    title)
  