有没有办法让 Emacs 在会话之间保存您的撤消历史? [英] Is there any way to have Emacs save your undo history between sessions?

问题描述

有没有办法让 EMACS 在会话之间保存您的撤消历史?

Is there any way to have EMACS save your undo history between sessions?

我知道 savehist lib、saveplace lib、desktop lib 和 windows lib，这些都提供了一些会话控制，但似乎都没有保存撤消历史.

I'm aware of the savehist lib, the saveplace lib, the desktop lib, and the windows lib, these all provide some session control but none seem to save the undo history.

推荐答案

这是我写的一些代码，似乎可以解决问题.它不是防弹的，因为它不能处理 Emacs 所做的所有文件处理复杂问题(例如，覆盖自动保存文件的放置位置、符号链接处理等).但是，它似乎对我操作的一些简单文本文件有效.

Here's some code I wrote which seems to do the trick. It isn't bullet-proof, as in, it doesn't handle all the file handling intricacies that Emacs does (e.g. overriding where auto-save files are put, symlink handling, etc.). But, it seemed to do the trick for some simple text files I manipulated.

(defun save-undo-filename (orig-name)
  "given a filename return the file name in which to save the undo list"
  (concat (file-name-directory orig-name)
          "."
          (file-name-nondirectory orig-name)
          ".undo"))

(defun save-undo-list ()
  "Save the undo list to a file"
  (save-excursion
    (ignore-errors
      (let ((undo-to-save `(setq buffer-undo-list ',buffer-undo-list))
            (undo-file-name (save-undo-filename (buffer-file-name))))
        (find-file undo-file-name)
        (erase-buffer)
        (let (print-level
              print-length)
          (print undo-to-save (current-buffer)))
        (let ((write-file-hooks (remove 'save-undo-list write-file-hooks)))
          (save-buffer))
        (kill-buffer))))
  nil)

(defvar handling-undo-saving nil)

(defun load-undo-list ()
  "load the undo list if appropriate"
  (ignore-errors
    (when (and
           (not handling-undo-saving)
           (null buffer-undo-list)
           (file-exists-p (save-undo-filename (buffer-file-name))))
      (let* ((handling-undo-saving t)
             (undo-buffer-to-eval (find-file-noselect (save-undo-filename (buffer-file-name)))))
        (eval (read undo-buffer-to-eval))))))

(add-hook 'write-file-hooks 'save-undo-list)
(add-hook 'find-file-hook 'load-undo-list)

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