Method: (P-NREVERSE PERSISTENT-CONS)

Source

(defmethod p-nreverse ((object persistent-cons))
  (let* ((previous object)
         (current (p-cdr previous)))
    (setf (p-cdr previous) '())
    (loop until (p-endp current)
          do (let ((next (p-cdr current)))
               (setf (p-cdr current) previous
                     previous current
                     current next)))
    previous))