3
如何接受以下输入?方案中的模式匹配
(list of 0 or more charcters and ends with 3) or
(list of 1 or more characters 4 and 0 or more characters after 4)
像
(match (list 3)) -> #t
(match (list 1 2 3)) -> #t
(match (list 1 2 3 4)) -> #t
(match (list 1 2 3 4 5)) -> #t
(match (list 4)) -> #f
编辑:这不是我的功课。我试图从PAIP写ELIZA之类的东西,但我只知道如何编写一个以单词开始的模式。