;;;两表做左对齐加法运算
(defun add (lst1 lst2)
(if (< (length lst1) (length lst2))
(add lst2 lst1)
(progn
(setq i 0 lst nil)
(while (< i (length lst1) )
(setq a (nth i lst1))
(setq b (nth i lst2))
(if (vl-catch-all-error-p (vl-catch-all-apply '+ (list a b))) (setq c a) (setq c (+ a b)))
(setq lst (cons c lst))
(setq i (+ 1 i))
)
)
)
(reverse lst)
)
(add '(1 2 3 4 5 6 7 8 9) '(0 2 4 6 8 10 12 14 16 18 20))