方案中的变量让表达式莫名其妙地不受约束

Question

我得到一个错误，说 dataInput 没有绑定。我不知道为什么。这似乎是一个有效的 let 表达式。请解释。非常感谢！

 (define imageList "/home/perry/dir_image_search_list") ;text file of image exif data in a proper list
 (if (file-exists? imageList)
     (let ((dataInput (open-input-file imageList)) (raw-data (read dataInput))) ;dataInput is not bound for some reason
         (if (eof-object? raw-data)
             (begin
                 (display "file is empty")
                 (close-port dataInput)
                 '()
             )
         (begin
             (car raw-data) ;placeholder for future code to process the list
             (close-port dataInput)
         ))
     )
     (begin
         (display "file not found")
         '()
     )
 )