方案：顺序执行
我需要做的事情基本上是这样的：
(define test
(λ (ls1 ls2)
(cond
((empty? ls2) null)
(else
(append ls1 (car ls2)) (test ls1 (cdr ls2))) (displayln ls1))))
问题是 else 子句及其后面的函数。我需要执行 else 子句的两个子句，然后需要执行最后一个函数，但我无法获得正确的语法。
我需要 (test '(1 2 3) '(4 5 6)) 来显示 '(1 2 3 4 5 6) 并且它必须使用递归调用。
任何建议表示赞赏。
谢谢。
I need to do something basically like this:
(define test
(λ (ls1 ls2)
(cond
((empty? ls2) null)
(else
(append ls1 (car ls2)) (test ls1 (cdr ls2))) (displayln ls1))))
The issue is the else-clause and the function that follows it. I need both clauses of the else-clause to execute and then I need the last function to execute but I can't get the syntax right.
I need (test '(1 2 3) '(4 5 6)) to result in displaying '(1 2 3 4 5 6) and it has to use the recursive call.
Any advice is appreciated.
Thanks.
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那里有几个问题。首先，您在列表和原子（不是列表）上进行追加...至少如果
(car l2)不是列表。其次，您可能认为(append l1 (list (car l2))修改了l1。但事实并非如此。结果是一个新列表。要对您的操作进行排序你可以像拉斯曼所说的那样，但你也可以编写以下内容，
这具有完全相同的行为。
There is several problem there. First you make an append on a list and an atom (not a list)... at least if
(car l2)is not a list. Second you probably think that(append l1 (list (car l2))modifiesl1. But this is not the case. The result is a new list.To sequence your operation you can do as larsmans have said. But you can also write the following
This has exactly the same behavior.
如果您非常想递归地解决这个问题，并且不关心返回值，请使用
（顺便说一句，这是非常低效的：O(n × m)内存分配.)
If you desperately want to solve this recursively, and you don't care about the return value, use
(This is very inefficient btw: O(n × m) memory allocations.)