(scheme file)

文件操作库。

导入

(import (scheme file))

端口操作

打开文件

函数	描述	示例
call-with-input-file	打开输入文件	(call-with-input-file "data.txt" read)
call-with-output-file	打开输出文件	(call-with-output-file "out.txt" write-fn)
with-input-from-file	重定向输入	(with-input-from-file "data.txt" thunk)
with-output-to-file	重定向输出	(with-output-to-file "out.txt" thunk)

打开二进制文件

函数	描述	示例
open-binary-input-file	打开二进制输入	(open-binary-input-file "data.bin")
open-binary-output-file	打开二进制输出	(open-binary-output-file "out.bin")

完整示例

(import (scheme file)
        (scheme base))

;; 读取整个文件
(define (read-file filename)
  (call-with-input-file filename
    (lambda (port)
      (let loop ((result '()))
        (let ((line (read-line port)))
          (if (eof-object? line)
              (reverse result)
              (loop (cons line result))))))))

;; 写入文件
(define (write-file filename lines)
  (call-with-output-file filename
    (lambda (port)
      (for-each (lambda (line)
                  (display line port)
                  (newline port))
                lines))))

;; 复制文件
(define (copy-file from to)
  (call-with-input-file from
    (lambda (in)
      (call-with-output-file to
        (lambda (out)
          (let loop ((char (read-char in)))
            (unless (eof-object? char)
              (write-char char out)
              (loop (read-char in)))))))))