XahTV 2021-07-14 emacs lisp, slash backslash, what should be the filepath separator

XahTV 2021-07-14 emacs lisp, slash backslash, what should be the filepath separator
(defun xah-slash-to-backslash (&optional pos1 pos2)
  "Replace slash by backslash on current line or region.
Version 2021-07-14"
  (interactive)
  (let (p1 p2)
    (if pos1
        (setq p1 pos1 p2 pos2)
      (if (region-active-p)
          (setq p1 (region-beginning) p2 (region-end))
        (setq p1 (line-beginning-position) p2 (line-end-position))))
    (save-restriction
      (narrow-to-region p1 p2)
      (let ((case-fold-search nil))
        (goto-char (point-min))
        (while (search-forward "/" nil t)
          (replace-match "\\\\"))))))

(defun xah-slash-to-double-backslash (&optional pos1 pos2)
  "Replace slash by double backslash on current line or region.
Version 2021-07-14"
  (interactive)
  (let (p1 p2)
    (if pos1
        (setq p1 pos1 p2 pos2)
      (if (region-active-p)
          (setq p1 (region-beginning) p2 (region-end))
        (setq p1 (line-beginning-position) p2 (line-end-position))))
    (save-restriction
      (narrow-to-region p1 p2)
      (let ((case-fold-search nil))
        (goto-char (point-min))
        (while (search-forward "/" nil t)
          (replace-match "\\\\\\\\"))))))

(defun xah-double-backslash-to-slash (&optional pos1 pos2)
  "Replace double backslash by slash on current line or region.
Version 2021-07-14"
  (interactive)
  (let (p1 p2)
    (if pos1
        (setq p1 pos1 p2 pos2)
      (if (region-active-p)
          (setq p1 (region-beginning) p2 (region-end))
        (setq p1 (line-beginning-position) p2 (line-end-position))))
    (save-restriction
      (narrow-to-region p1 p2)
      (let ((case-fold-search nil))
        (goto-char (point-min))
        (while (search-forward "\\\\" nil t)
          (replace-match "/"))))))

xah_talk_show_2021-07-14.txt