Common Lisp lambda表达式错误
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.phpCommon Lisp lambda表达式错误
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。
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)))))
'(DEFUN REMDOUBLES(输入输出)'和'(COND')之间有一个额外的左括号。正确缩进代码!任何半像素的编辑都会为你缩进。 – Gilles
在第('(NULL INPUT)NILL)行中还有一个错误,应该是'((NULL INPUT)NIL)' –