Toggle between backslashes and forward slashes

toggle-backslash.el

(defun toggle-backslash-line ()
  "Toggle all forward slashes to backslashes for the current line."
  (interactive)
  (save-excursion
    (if (use-region-p)
        (setq myBoundaries (cons (region-beginning) (region-end)))
        (setq myBoundaries (bounds-of-thing-at-point 'line)))
      
    (save-restriction
      (goto-char (car myBoundaries))
      (narrow-to-region (car myBoundaries) (cdr myBoundaries))
      (if (search-forward "/" nil t)
          (progn
            (goto-char (car myBoundaries))
            (while (search-forward "/" nil t) (replace-match "\\\\" 'literal)))
        (progn
          (goto-char (car myBoundaries))
          (while (search-forward "\\" nil t) (replace-match "/")))
        )
      ))
    (if (use-region-p)
        (progn
          (set-mark (car myBoundaries))
          (goto-char (cdr myBoundaries)))))

(global-set-key [(control x) (control ?\\)] 'toggle-backslash-line)