第拾陸章學習 Lisp 3rd Edition, Winston & Horn

SPECIAL VARIABLES
--------------------------------------------------

Bindings Could Be Kept on a Record of Calls

(defun first-of-first1 (l)
    (first (auxiliary1 l)))
(defun auxiliary1 (l)
    (first l))

(defun first-of-first2 (l)
    (first (auxiliary2)))
(defun auxiliary2 ()
    (first l))