使用嵌套列表（未知程度）（球拍）

Question

这是我第一次发帖，所以如果我搞砸了请告诉我:)

这是一个我无法导入或使用的作业 "for functions"。所以我有一个嵌套列表，但我不知道它嵌套的程度，所以它可能是这样的：

'(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
or
'((#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>))
or
'(((#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>))
((#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>))
((#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>))
((#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)
(#<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt> #<procedure:curried:tt>)))
or
4 times bigger then that

注：虽然不一定是4倍

然后我必须对每个函数应用一个参数，没有改变列表中的位置，所以上面的函数可能是：

'(1 2 3 4)
and
'((1 2 3 4)
(1 2 3 4)
(2 3 4 5)
(9 8 2 1))
and
'(((1 2 3 4)
(1 2 3 4)
(2 3 4 5)
(9 8 2 1))
((1 2 3 4)
(1 2 3 4)
(2 3 4 5)
(9 8 2 1))
((1 2 3 4)
(1 2 3 4)
(2 3 4 5)
(9 8 2 1))
((1 2 3 4)
(1 2 3 4)
(2 3 4 5)
(9 8 2 1)))
and so on

对于未知度部分如何解决这个问题，我真的很困惑。用已知的度数来解决是非常简单的，你只需要一系列的函数与 car 和 cdr 循环。老实说，我不知道如何开始 未知学位 部分，所以非常感谢您的帮助！

Answer 1

这基本上就像遍历一个 s 表达式。您可以像 s 表达式一样对数据建模：

; NestedFuncs is one of
; - Func
; - [List-of Nested-Funcs]

一旦完成，遍历它就很容易了。一个函数处理数据，第二个函数遍历列表。

#lang racket

(define (apply-nfs nfs arg)
  (if (list? nfs)
      (apply-nf-list nfs arg)
      (nfs arg)))

(define (apply-nf-list nf arg)
  (if (empty? nf)
      '()
      (cons (apply-nfs (car nf) arg)
            (apply-nf-list (cdr nf) arg))))

这是一个示例和输出：


(define nf-ex
  `((,add1 ,sub1 ,sub1 ,add1)
    (,sub1 (,add1 ,add1) ,add1 ,sub1)
    (,add1 ,add1)
    (,add1 ,add1 (,sub1 (,add1)) ,add1)))

(apply-nfs nf-ex 3)
; => '((4 2 2 4) (2 (4 4) 4 2) (4 4) (4 4 (2 (4)) 4))

使用嵌套列表（未知程度）（球拍）

Working with nested-list (to unknown degree) (Racket)

scheme

list

nested-lists

racket