Question

我一直致力于一个学校项目，它从类文件中获取函数并将它们转换为对象/类。该任务都是关于方案中的面向对象编程。

然而我的问题是我的代码格式不正确。

每当我给它传递一个文件时，它给我的输出将类的方法包装在一个列表中，使得类永远不会真正被声明。我不能为我的生活弄清楚如何让括号包装方法列表去除。

我真的很感激任何帮助。

下面是输出，类文件和代码。

(define pointInstance  
  (let ((myx 1) (myy 2))  
    (lambda msg  
      (cond  
       (((eq? (car msg) getx) myx)  
        ((eq? (car msg) gety) myy)  
        ((eq? (car msg) setx) (set! myx x))  
        ((eq? (car msg) show) (begin (display "[") (display myx) (display ",") (display  myy) (display "]"))))))))

如果您在cond之后看一下，您将看到所有这些eq语句如何包含在列表中。我不能让这个工作正常，除非他们没有被顶级名单包裹。

;;;; PART1 ---  A super-easy set of classes. Just models points and lines. Tests all of >the 
;; basics of class behavior without touching on anything particularly complex.

(class pointInstance (parent:) (constructor_args:)
  (ivars: (myx 1) (myy 2))
  (methods: 
   (getx () myx)
   (gety () myy)
   (setx (x) (set! myx x))
   (show () (begin (display "[") (display myx) (display ",") (display myy) (display "]")))
   ))



(require (lib "trace.ss"))

;; Continue reading until you hit the end of the file, all the while
;; building a list with the contents 
(define load-file
 (lambda (port)
 (let ((rec (read port)))
 (if (eof-object? rec)
 '()
 (cons rec (load-file port))))))

;; Open a port based on a file name using open-input-file
(define (load fname)
 (let ((fport (open-input-file fname)))
 (load-file fport)))



;(define lis (load "C:\\Users\\Logan\\Desktop\\simpletest.txt"))
;(define lis (load "C:\\Users\\Logan\\Desktop\\complextest.txt"))
(define lis (load "C:\\Users\\Logan\\Desktop\\pointinstance.txt"))

;(display  (cdaddr (cdddar lis)))

(define makeMethodList
  (lambda (listToMake retList)
    ;(display listToMake)
    (cond
      [(null? listToMake)
       retList
       ;(display "The list passed in to parse was null")
      ]
      [else
      (makeMethodList (cdr listToMake) (append retList (list (getMethodLine         listToMake))))
      ]
        )
    ))
;(trace makeMethodList)

;this works provided you just pass in the function line
(define getMethodLine 
  (lambda (functionList)
    `((eq? (car msg) ,(caar functionList)) ,(caddar functionList))))

(define load-classes
  (lambda paramList
    (cond 
    [(null? paramList) (display "Your parameters are null, man.")]
[(null? (car paramList))(display "Done creating class definitions.")]
[(not (null? (car paramList)))

     (begin 
     (let* ((className (cadaar paramList))
            (classInstanceVars (cdaddr (cddaar paramList)))
            (classMethodList (cdr (cadddr (cddaar paramList))))
            (desiredMethodList (makeMethodList classMethodList  '()))

            )
       ;(display "Classname: ")
       ;(display className)
       ;(newline)(newline)

       ;(display "Class Instance Vars: ")
       ;(display classInstanceVars)
       ;(newline)(newline)

       ;(display "Class Method List: ")
       ;(display classMethodList)
       ;(newline)

       ;(display "Desired Method List: ")
       ;(display desiredMethodList))
       ;(newline)(newline)

;---------------------------------------------------- 
;do not delete the below code!`
      `(define ,className 
         (let  ,classInstanceVars 
           (lambda msg 
             ;return the function list here
             (cond ,(makeMethodList classMethodList  '())))
             ))
;---------------------------------------------------
))]
)
))

(load-classes lis)
;(load-classes lis)
;(load-classes-helper lis)
;(load-classes "simpletest.txt")
;(load-classes "complextest.txt")

;method list
;(display (cdr (cadddr (cddaar <class>))))

Answer 1

cond的第1个子句中有太多左括号。

IE：

(((eq? (car msg) getx) myx)
^

<强>更新

你在找这个吗？

(cond ,@(makeMethodList classMethodList  '())
      ^^

或者你可以这样做：

(cond . ,(makeMethodList classMethodList  '())

方案格式帮助

1 个答案: