通過EOF的Guile Scheme讀線讀取

Question

使用guile 1.8或guile 2，下面的代碼讀取過去的EOF，看起來是多餘的一行，然後停止。這是一個提取的大型程序所產生的效果是看似腐敗了以前讀取的數據。我是否正確使用read-line或測試eof-object？

(use-modules (ice-9 rdelim)) 

(define f 
    (lambda (p) 
    (let loop ((line (read-line p))) 
     (format #t "line: ~a\n" line) 
     (if (not (eof-object? (peek-char p))) 
     (begin 
     (let ((m (string-match "^[ \t]*#" line))) 
      (if m 
      (begin 
       (format #t "comment: ~a\n" (match:string m)) 
       (loop (read-line p)) 
      ))) 
     (format #t "read next line\n") 
     (loop (read-line p))))))) 

(define main 
    (lambda() 
    (let ((h (open-input-file "test"))) 
     (f h)))) 

下面是一個最小的樣品虛擬輸入文件：

1 
2 
3 
# comment line 
4 
5 
1 
2 
3 
# comment line 
4 
5 
1 
2 
3 
# comment line 
4 
5 

它需要比渴望體現該問題的幾行。對代碼示例的長度抱歉，但只有在代碼達到這種複雜程度（儘管很小）時纔會出現問題。

Answer 1

我建議重寫過程，它似乎不是正確的方式來讀取文件並循環播放它的行。請試試這個：

(define (f) 
    (let loop ((line (read-line))) 
    (if (not (eof-object? line)) 
     (begin 
      (format #t "line: ~a\n" line) 
      (let ((m (string-match "^[ \t]*#" line))) 
      (if m (format #t "comment: ~a\n" line))) 
      (format #t "read next line\n") 
      (loop (read-line)))))) 

(define (main) 
    (with-input-from-file "test" f)) 

與樣品輸入，調用控制檯上(main)輸出以下，這希望是你所期望的：

line: 1 
read next line 
line: 2 
read next line 
line: 3 
read next line 
line: # comment line 
comment: # comment line 
read next line 
line: 4 
read next line 
line: 5 
read next line 
line: 1 
read next line 
line: 2 
read next line 
line: 3 
read next line 
line: # comment line 
comment: # comment line 
read next line 
line: 4 
read next line 
line: 5 
read next line 
line: 1 
read next line 
line: 2 
read next line 
line: 3 
read next line 
line: # comment line 
comment: # comment line 
read next line 
line: 4 
read next line 
line: 5 
read next line