Breadcrumb for Emacs

This is a fork of the Breadcrumb 1.1.4 package that is hosted at http://breadcrumbemacs.sourceforge.net/. The original package is written by William W. Wong.

The remainder of this document is copied and pasted from the commentary written by William W. Wong in breadcrumb.el, with a few additions by myself (Philip Weaver).

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GNU Emacs; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

Overview

• Set bookmarks quickly with minimal hassle.
• Jump to and cycle through bookmarks quickly.
• Bookmarks are global across buffers.
• Support cycling through the bookmarks in the local buffer as well.
• Bookmarks are persistent across Emacs editing sessions.
• Different types of buffer can be bookmarked: file, dired, info, and system.
• Integrated with find-tag and tags-search to set bookmark automatically.
• Bookmark menu allows interactively listing and managing of bookmarks.
• Interactively visit bookmarks in the other window in the bookmark menu.

Commentary

The Breadcrumb package allows you to set a series of breadcrumb bookmarks in Emacs and later jump to them quickly. They can be set with a key-stroke and jumped to with a key-stroke. The bookmarks are global across different Emacs buffers and thus leaving a trail of breadcrumb among them that you can jump back to easily. If a file is not loaded when jumping to its bookmark, it is loaded as a result.

Different types of buffer can be bookmarked. The supported types are: file, DIRED, Info, and system buffers.

The breadcrumb bookmarks are not the same as the Emacs built-in bookmark, which requires a name. The breadcrumb bookmarks have no names so that they can be set and jumped to quickly. When one is set, it is added to a circular queue. The bookmarks in the queue are cycled through when jumping. The command bc-previous jumps back in the reverse order of the bookmarks added. The command bc-next jumps forth in the order they are added. Basically bc-previous goes back in the list and bc-next goes forth in the list.

The bookmark queue’s max size is controlled by the ‘bc-bookmark-limit’ variable. The oldest bookmark is dropped when adding a new one exceeds the limit. The default queue limit is 16. Feel free to increase it to the number of bookmarks you want to have.

Emacs’ find-tag and tags-search have been hooked so that a breadcrumb bookmark is set when they are invoked. This allows tag search navigation to leave a trail of breadcrumbs to go back on. Add more defadvice hooks on other functions that you want to intercept.

When I started using Emacs, one feature I missed sorely from my old editor Epsilon is the ability to set a series of marks across different buffers and jump to them quickly. Emacs has the feature of set-mark-command and C-U C-SPC to jump back to the marks but that only works in the same buffer. Often time I needed to visit several files before jumping back to where I was, especially during tag-find navigation. Another option is to use the Emacs’ bookmark feature, but that requires giving a name in setting and jumping, which is cumbersome to use.

Since none of the options are satisfactory, I ended up writing this package to address the need. Hope you find it helpful as well.

Installation:

Put breadcrumb.el in your load-path. The load-path is usually ~/elisp/. It’s set in your .emacs, like this:

(setq load-path (append (list (expand-file-name "~/elisp")) load-path))

Add the following to your .emacs startup file.

(require 'breadcrumb)

or add the autoloads for the public command functions.

(autoload 'bc-set               "breadcrumb" "Set bookmark in current point."   t)
(autoload 'bc-previous          "breadcrumb" "Go to previous bookmark."         t)
(autoload 'bc-next              "breadcrumb" "Go to next bookmark."             t)
(autoload 'bc-local-previous    "breadcrumb" "Go to previous local bookmark."   t)
(autoload 'bc-local-next        "breadcrumb" "Go to next local bookmark."       t)
(autoload 'bc-goto-current      "breadcrumb" "Go to the current bookmark."      t)
(autoload 'bc-list              "breadcrumb" "List all bookmarks in menu mode." t)
(autoload 'bc-clear             "breadcrumb" "Clear all bookmarks."             t)

Configuration:

Assign the commands to some keys in your .emacs file.

Examples below assign a set of keys to the breadcrumb bookmark functions.

(global-set-key [(shift space)]         'bc-set)            ;; Shift-SPACE for set bookmark
(global-set-key [(meta j)]              'bc-previous)       ;; M-j for jump to previous
(global-set-key [(shift meta j)]        'bc-next)           ;; Shift-M-j for jump to next
(global-set-key [(meta up)]             'bc-local-previous) ;; M-up-arrow for local previous
(global-set-key [(meta down)]           'bc-local-next)     ;; M-down-arrow for local next
(global-set-key [(control c)(j)]        'bc-goto-current)   ;; C-c j for jump to current bookmark
(global-set-key [(control x)(meta j)]   'bc-list)           ;; C-x M-j for the bookmark menu list

Another set of bindings similar to MS Visual Studio bookmark setting.

(global-set-key [(control f2)]          'bc-set)
(global-set-key [(f2)]                  'bc-previous)
(global-set-key [(shift f2)]            'bc-next)
(global-set-key [(meta f2)]             'bc-list)

Acknowledgements

Thanks to Karl Fogel for his bookmark.el package where I learned about bookmarking in Emacs.

History:

• 2010/09 Philip Weaver
  • Add argument other-window-p to bc-list function
  • Define bc-revert-buffer and bind ‘g’ to revert-buffer
  • Add bc-switch-buffer-func
  • Other minor changes and cleanup (dos2unix, delete-trailing-whitespace, eliminate compile errors and warnings)
• 2008/02/29 William Wong
  • Minor bug fixes and cleanup
  • Version 1.1.4 release
• 2008/02/10 William Wong
  • Add hook to query-replace to set breadcrumb bookmark before replacing.
  • Version 1.1.3 release
• 2008/02/07 William Wong
  • Add compatibility funciton for quit-window to support both Emacs and XEmacs.
  • Change the sample key bindings to be compatible with both Emacs and XEmacs.
  • Add cycling-back the cursor when deleting, un-deleting, or visiting bookmarks in the Breadcrumb Bookmarks mode menu.
  • Thanks to Thorsten Bonow for making it work on XEmacs.
  • Version 1.1.2 release
• 2008/02/01 William Wong
  • Add a CR at the end of the saved bookmark file to stop the Emacs’ warning at exit.
  • Version 1.1.1 release
• 2008/01/26 William Wong
  • Enhancement, refactoring, bug fixes.
  • Add Breadcrumb Bookmarks mode menu.
  • Add visiting bookmark buffers in the other window.
  • Add saving and restoration of bookmarks across sessions.
  • Add local buffer jump
  • Add going to the last jumped bookmark (current bookmark).
  • Version 1.1 release
• 2004/10/18 William Wong
  • Initial version.
  • Version 1.0 release