(defclass request-meta (c2mop:standard-class)
  ())
(defclass dynamic-slot (c2mop:standard-direct-slot-definition)
  ())

(defmethod c2mop:validate-superclass ((class request-meta) (metaclass standard-class))
  t)

(defmethod c2mop:validate-superclass ((class dynamic-slot) (metaclass standard-class))
  t)

(defmethod c2mop:slot-definition-allocation ((slot dynamic-slot))
  (call-next-method))

(defmethod c2mop:compute-effective-slot-definition ((class dynamic-slot) name dslots)
  (declare (ignore name dslots))
  (let ((slot (call-next-method)))
    slot))

(defmethod make-instance ((class request-meta) &rest initargs &key &allow-other-keys)
  (let ((to-be-slots (second (member :sym initargs))))
    (let ((nslots
            (mapcar (lambda (direct)
                      (sb-mop:compute-effective-slot-definition class
                                                                (c2mop:slot-definition-name direct)
                                                                (list direct)))
                    (mapcar (lambda (sym)
                              (make-instance 'dynamic-slot :name sym))
                            to-be-slots))))
      
      (apply #'call-next-method class initargs))))