Method: (initialize-instance after url-method)

Source

(defmethod initialize-instance :after ((url-spec url-method) &key) 
  (with-slots (url url-regex wethod-urls wethod-url-regexes) url-spec
    (setf url-regex (create-url-scanner (strcat "^" url)))
    (setf wethod-url-regexes (mapcar #'make-url-handler-regex wethod-urls))))