第一篇LISP小程序

代码

(defparameter *small* 1)
(defparameter *big*   100)

(defun guess-my-number()
  (ash (+ *small* *big*) -1)
)

(defun smaller()
  (setf *big* (1- (guess-my-number)))
  (guess-my-number)
)

(defun biger()
  (setf *small* (1- (guess-my-number)))
  (guess-my-number)
)

(defun startover()
  (defparameter *small* 1)
  (defparameter *big*   100)
  (guess-my-number)
)

运行

CL-USER> (guess-my-number)
50
CL-USER> (biger)
74
CL-USER> (biger)
86
CL-USER> (biger)
92
CL-USER> (smaller)
88
CL-USER> (startover)
50
CL-USER> (smaller)
25
CL-USER> (smaller)
12
CL-USER> (smaller)
6
CL-USER> (biger)
8