LISP：如何从文件中读取内容并将其写入另一个文件？

Question

我想编写一个函数，该函数将两个文件的名称作为参数，并将内容从第一个文件复制到第二个文件。

到目前为止，我编写了一个从文件中读取的函数：

(defun readFile (name)
 (let ((in (open name)))
  (format t "~a~%" (read-line in))
   (close in)))

还有一个将字符串写入文件的函数：

(defun writeFile (name content)
(with-open-file (stream name
    :direction :output
    :if-exists :overwrite
    :if-does-not-exist :create)
(format stream content)))

按照 Savantes 的说明，我再次编写了该函数，它的外观如下：

(defun read-write-to-file (input-file output-file)
(WITH-OPEN-FILE (output-stream output-file
         :direction :output
         :if-exists :new-version
         :if-does-not-exist :create)
  (WITH-OPEN-FILE (input-stream input-file
                 :direction :input)
        (FORMAT output-stream "~a" (READ input-stream nil 'eof))
)))

现在唯一的问题是它没有读取整个文件。

Answer 1

Common Lisp 食谱实际上包含了您问题的答案：

http://cl-cookbook.sourceforge.net/io.html

请参阅该页面底部的“批量 I/O”部分。

稍加修正和修改后，代码将如下所示：

(defun my-copy-file (from-file to-file)
  (with-open-file (input-stream from-file
                :direction :input
                :element-type '(unsigned-byte 8))
    (with-open-file (output-stream to-file
                   :direction :output
                   :if-exists :supersede
                   :if-does-not-exist :create
                   :element-type '(unsigned-byte 8))
      (let ((buf (make-array 4096 :element-type (stream-element-type input-stream))))
    (loop for pos = (read-sequence buf input-stream)
       while (plusp pos)
       do (write-sequence buf output-stream :end pos))))))

这应该能够处理文本文件和二进制文件。