递归模板 2 多条件
(defun fn (x)
(cond (test-condition1 the-value1)
(test-condition2 the-value2)
...
...
...
(t (fn reduced-argument-x))))
CL-USER 2788 > (defun my-fib (n)
(cond ((= n 1) 1)
((= n 2) 1)
(t (+
(my-fib (- n 1))
(my-fib (- n 2))))))
MY-FIB
CL-USER 2789 > (my-fib 1)
1
CL-USER 2790 > (my-fib 2)
1
CL-USER 2791 > (my-fib 3)
2
CL-USER 2792 > (my-fib 4)
3
CL-USER 2793 > (my-fib 5)
5
CL-USER 2794 > (my-fib 6)
8
CL-USER 2795 > (my-fib 7)
13