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246 lines
9.1 KiB
EmacsLisp
246 lines
9.1 KiB
EmacsLisp
;;; saveplace.el --- automatically save place in files.
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;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
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;; Author: Karl Fogel <kfogel@cs.oberlin.edu>
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;; Maintainer: FSF
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;; Created: July, 1993
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;; Keywords: bookmarks, placeholders
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; Automatically save place in files, so that visiting them later
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;; (even during a different Emacs session) automatically moves point
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;; to the saved position, when the file is first found. Uses the
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;; value of buffer-local variable save-place to determine whether to
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;; save position or not.
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;;
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;; Thanks to Stefan Schoef, who sent a patch with the
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;; `save-place-version-control' stuff in it.
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;;; Code:
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;; this is what I was using during testing:
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;; (define-key ctl-x-map "p" 'toggle-save-place)
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(defgroup save-place nil
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"Automatically save place in files."
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:group 'data)
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(defvar save-place-alist nil
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"Alist of saved places to go back to when revisiting files.
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Each element looks like (FILENAME . POSITION);
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visiting file FILENAME goes automatically to position POSITION
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rather than the beginning of the buffer.
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This alist is saved between Emacs sessions.")
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(defcustom save-place nil
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"*Non-nil means automatically save place in each file.
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This means when you visit a file, point goes to the last place
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where it was when you previously visited the same file.
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This variable is automatically buffer-local.
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If you wish your place in any file to always be automatically saved,
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simply put this in your `~/.emacs' file:
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\(setq-default save-place t\)"
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:type 'boolean
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:group 'save-place)
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(make-variable-buffer-local 'save-place)
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(defcustom save-place-file (convert-standard-filename "~/.emacs-places")
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"*Name of the file that records `save-place-alist' value."
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:type 'file
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:group 'save-place)
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(defcustom save-place-version-control nil
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"*Controls whether to make numbered backups of master save-place file.
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It can have four values: t, nil, `never', and `nospecial'. The first
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three have the same meaning that they do for the variable
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`version-control', and the final value `nospecial' means just use the
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value of `version-control'."
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:type '(radio (const :tag "Unconditionally" t)
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(const :tag "For VC Files" nil)
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(const never)
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(const :tag "Use value of `version-control'" nospecial))
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:group 'save-place)
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(defvar save-place-loaded nil
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"Non-nil means that the `save-place-file' has been loaded.")
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(defcustom save-place-limit nil
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"Maximum number of entries to retain in the list; nil means no limit."
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:type '(choice (integer :tag "Entries" :value 1)
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(const :tag "No Limit" nil))
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:group 'save-place)
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(defun toggle-save-place (&optional parg)
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"Toggle whether to save your place in this file between sessions.
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If this mode is enabled, point is recorded when you kill the buffer
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or exit Emacs. Visiting this file again will go to that position,
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even in a later Emacs session.
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If called with a prefix arg, the mode is enabled if and only if
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the argument is positive.
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To save places automatically in all files, put this in your `.emacs' file:
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\(setq-default save-place t\)"
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(interactive "P")
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(if (not buffer-file-name)
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(message "Buffer `%s' not visiting a file" (buffer-name))
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(if (and save-place (or (not parg) (<= parg 0)))
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(progn
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(message "No place will be saved in this file")
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(setq save-place nil))
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(message "Place will be saved")
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(setq save-place t))))
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(defun save-place-to-alist ()
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;; put filename and point in a cons box and then cons that onto the
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;; front of the save-place-alist, if save-place is non-nil.
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;; Otherwise, just delete that file from the alist.
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;; first check to make sure alist has been loaded in from the master
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;; file. If not, do so, then feel free to modify the alist. It
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;; will be saved again when Emacs is killed.
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(or save-place-loaded (load-save-place-alist-from-file))
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(if buffer-file-name
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(progn
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(let ((cell (assoc buffer-file-name save-place-alist))
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(position (if (not (eq major-mode 'hexl-mode))
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(point)
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(1+ (hexl-current-address)))))
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(if cell
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(setq save-place-alist (delq cell save-place-alist)))
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(if (and save-place
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(not (= position 1))) ;; Optimize out the degenerate case.
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(setq save-place-alist
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(cons (cons buffer-file-name position)
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save-place-alist)))))))
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(defun save-place-alist-to-file ()
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(let ((file (expand-file-name save-place-file)))
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(save-excursion
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(message "Saving places to %s..." file)
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(set-buffer (get-buffer-create " *Saved Places*"))
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(delete-region (point-min) (point-max))
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(if (file-readable-p file)
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(insert-file-contents file))
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(delete-region (point-min) (point-max))
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(goto-char (point-min))
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(print save-place-alist (current-buffer))
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(let ((version-control
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(cond
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((null save-place-version-control) nil)
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((eq 'never save-place-version-control) 'never)
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((eq 'nospecial save-place-version-control) version-control)
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(t
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t))))
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(write-file file)
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(kill-buffer (current-buffer))
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(message "Saving places to %s...done" file)))))
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(defun load-save-place-alist-from-file ()
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(if (not save-place-loaded)
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(progn
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(setq save-place-loaded t)
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(let ((file (expand-file-name save-place-file)))
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;; make sure that the alist does not get overwritten, and then
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;; load it if it exists:
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(if (file-readable-p file)
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(save-excursion
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(message "Loading places from %s..." save-place-file)
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;; don't want to use find-file because we have been
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;; adding hooks to it.
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(set-buffer (get-buffer-create " *Saved Places*"))
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(delete-region (point-min) (point-max))
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(insert-file-contents file)
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(goto-char (point-min))
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(setq save-place-alist
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(car (read-from-string
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(buffer-substring (point-min) (point-max)))))
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;; If there is a limit, and we're over it, then we'll
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;; have to truncate the end of the list:
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(if save-place-limit
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(if (<= save-place-limit 0)
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;; Zero gets special cased. I'm not thrilled
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;; with this, but the loop for >= 1 is tight.
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(setq save-place-alist nil)
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;; Else the limit is >= 1, so enforce it by
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;; counting and then `setcdr'ing.
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(let ((s save-place-alist)
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(count 1))
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(while s
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(if (>= count save-place-limit)
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(setcdr s nil)
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(setq count (1+ count)))
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(setq s (cdr s))))))
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(kill-buffer (current-buffer))
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(message "Loading places from %s...done" file)))
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nil))))
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(defun save-places-to-alist ()
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;; go through buffer-list, saving places to alist if save-place is
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;; non-nil, deleting them from alist if it is nil.
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(let ((buf-list (buffer-list)))
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(while buf-list
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;; put this into a save-excursion in case someone is counting on
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;; another function in kill-emacs-hook to act on the last buffer
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;; they were in:
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(save-excursion
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(set-buffer (car buf-list))
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;; save-place checks buffer-file-name too, but we can avoid
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;; overhead of function call by checking here too.
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(and buffer-file-name (save-place-to-alist))
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(setq buf-list (cdr buf-list))))))
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(defun save-place-find-file-hook ()
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(or save-place-loaded (load-save-place-alist-from-file))
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(let ((cell (assoc buffer-file-name save-place-alist)))
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(if cell
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(progn
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(or after-find-file-from-revert-buffer
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(goto-char (cdr cell)))
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;; and make sure it will be saved again for later
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(setq save-place t)))))
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(defun save-place-kill-emacs-hook ()
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;; First update the alist. This loads the old save-place-file if nec.
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(save-places-to-alist)
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;; Now save the alist in the file, if we have ever loaded the file
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;; (including just now).
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(if save-place-loaded
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(save-place-alist-to-file)))
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(add-hook 'find-file-hooks 'save-place-find-file-hook t)
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(add-hook 'kill-emacs-hook 'save-place-kill-emacs-hook)
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(add-hook 'kill-buffer-hook 'save-place-to-alist)
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(provide 'saveplace) ; why not...
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;;; saveplace.el ends here
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