Common Lisp lambda表达式错误

Question

我想制作一个程序，它将重写给定的行而不在输出行中有重复项。我使用这个网站，作为一个编译器： https://www.tutorialspoint.com/execute_lisp_online.php

这里是我的代码

(SETQ X (LIST 2 -3 (LIST 4 3 0 2) (LIST 4 -4) (LIST 2 (LIST 2 0 2))-3))' 
(DEFUN SEARCHDEEP (WHAT WHERE) ;Function will find out if atom `WHAT`is in a row `WHERE` => works fine 
(COND 
    ((NULL WHERE) NIL) 
    (T (OR 
      (COND 
       ((ATOM (CAR WHERE)) (EQUAL WHAT (CAR WHERE))) 
       (T (SEARCHDEEP WHAT (CAR WHERE))) 
      ) 
      (SEARCHDEEP WHAT (CDR WHERE)) 
     ) 
    ) 
) 
) 

(DEFUN REMDOUBLES (INPUT OUTPUT) 
(
(COND 
    ((NULL INPUT) NILL) ;recursion exit 
    (T     ; funstion 
     (OR    ; step into or go forward 
      (COND 
       ((ATOM (CAR INPUT)) (COND 
             ((NOT (SEARCHDEEP (CAR INPUT) OUTPUT)) (APPEND OUTPUT INPUT)) ;if this atom wasn't added => append 
            ) 
       ) 
       (T (REMDOUBLES (CAR INPUT) OUTPUT)) ; step into (car input => list 
      ) 
      (REMDOUBLES (CRD INPUT) OUTPUT) ; go forward, car input is anatom 
     ) 
    ) 
) 
) 
) 

(SETQ OUT (QUOTE)) ;Empty row 
(REMDOUBLES X OUT) 
(PRINT OUT) 

我花了2小时以来检查这些代码，并在这里其他的答案，堆栈，但我不知道是什么我在这里想念吗？

我收到此错误：

*** - SYSTEM::%EXPAND-FORM:
(COND ((NULL INPUT) NILL)(T(OR (COND ((ATOM (CAR INPUT)) (COND ((NOT (SEARCHDEEP (CAR INPUT) OUTPUT))(APPEND OUTPUT INPUT)))) (T (REMDOUBLES (CAR INPUT) OUTPUT))) (REMDOUBLES (CRD INPUT) OUTPUT)))) should be a lambda expression

很抱歉的格式，我在函数式编程和Lisp新手，我不知道应该如何正确地完成。

Answer 1

您的代码：

第一行：

(DEFUN REMDOUBLES (INPUT OUTPUT) 

下联：你能解释一下单括号应该做些什么？

(

你记住基本的Lisp表达式的语法Lisp的？

(operator argument0 argument1 ... argumentn) 

这不是

((operator argument0 argument1 ... argumentn)) 

Sorry for the formatting, i am novice in functional programming and LISP, and i have no idea how it should be done properly.

下载从Touretzky介绍Lisp的书：https://www.cs.cmu.edu/~dst/LispBook/

然后了解有代码的Lisp的样子。

您还可以使用Lisp的格式化代码为您提供：

这是您的格式化代码：

[4]> (pprint '(DEFUN SEARCHDEEP (WHAT WHERE) ;Function will find out if atom `WHAT`is in a row `WHERE` => works fine 
(COND 
    ((NULL WHERE) NIL) 
    (T (OR 
      (COND 
       ((ATOM (CAR WHERE)) (EQUAL WHAT (CAR WHERE))) 
       (T (SEARCHDEEP WHAT (CAR WHERE))) 
      ) 
      (SEARCHDEEP WHAT (CDR WHERE)) 
     ) 
    ) 
) 
)) 

这是格式化代码：

(DEFUN SEARCHDEEP (WHAT WHERE) 
(COND ((NULL WHERE) NIL) 
    (T 
    (OR 
    (COND ((ATOM (CAR WHERE)) (EQUAL WHAT (CAR WHERE))) 
    (T (SEARCHDEEP WHAT (CAR WHERE)))) 
    (SEARCHDEEP WHAT (CDR WHERE)))))) 

但它会更好写成：

(DEFUN SEARCHDEEP (WHAT WHERE) 
    (WHEN WHERE 
    (OR (IF (ATOM (CAR WHERE)) 
      (EQUAL WHAT (CAR WHERE)) 
      (SEARCHDEEP WHAT (CAR WHERE))) 
     (SEARCHDEEP WHAT (CDR WHERE)))))