05/10/02 04:39:29
>>606
宿題だとすると labels の内部関数はつかっちゃだめかも？ということで
親切にも別解だっ．
;; 再帰関数一つ
(defun plus-minus (lst &optional plus minus &aux (x (car lst)) (xs (cdr lst)))
(cond ((null x)
(values plus minus))
((>= x 0)
(plus-minus xs (cons x plus) minus))
(t
(plus-minus xs plus (cons x minus)))))
;; メソッド一つ
(defmethod plus-minus-2 ((lst null) &optional plus minus)
(values plus minus))
(defmethod plus-minus-2 ((lst cons) &optional plus minus)
(if (>= (car lst) 0)
(plus-minus-2 (cdr lst) (cons (car lst) plus) minus)
(plus-minus-2 (cdr lst) plus (cons (car lst) minus))))