redo.el provides a linear undo/redo system which is easy to understand for many people. However, redo.el is out-of-date and often destroys the contents of buffer because the behavior of
‘primitive-undo’ has been slightly different from old one since Emacs 22. redo+.el is a fork of redo.el and correctly works in newer version of Emacs. This program also adds items to menubar/toolbar.
To use redo+.el, save this file in a directory listed in load-path and add the following to your ~/.emacs:
(require 'redo+) (global-set-key (kbd "C-?") 'redo)
If you’d like to discard the old undo branch immediately, put an additional line as:
(setq undo-no-redo t)
Hi, thank you for providing redo+. Because I could not find any contact information I try this way to contact you (I don’t speak Japanese, so I’m totally lost on your web-pages ;)
When loading redo+ (the version on EmacsWiki) in my Emacs 22.3.1 I get the following error message:
Debugger entered--Lisp error: (wrong-type-argument consp nil) setcar(nil (and (not buffer-read-only) (consp buffer-undo-list) (or (not ...) (listp pending-undo-list)))) (lambda (map) (setcar (cdr ...) (quote ...)))((keymap))
It seems as when building the menu-items, some list may contain a nil. The following patch worked for me:
--- redo+.el 2011-01-07 08:51:07.000000000 +0100 +++ my-redo+.el 2011-01-07 08:44:24.000000000 +0100 @@ -262,14 +262,16 @@ (unless (featurep 'xemacs) ;; condition to undo (mapc (lambda (map) - (setcar (cdr (memq :enable (assq 'undo (cdr map)))) - '(and (not buffer-read-only) - (consp buffer-undo-list) - (or (not (or (eq last-buffer-undo-list - buffer-undo-list) - (eq last-buffer-undo-list - (cdr buffer-undo-list)))) - (listp pending-undo-list))))) + (let ((p (cdr (memq :enable (assq 'undo (cdr map)))))) + (if p + (setcar p + '(and (not buffer-read-only) + (consp buffer-undo-list) + (or (not (or (eq last-buffer-undo-list + buffer-undo-list) + (eq last-buffer-undo-list + (cdr buffer-undo-list)))) + (listp pending-undo-list))))))) (append (list menu-bar-edit-menu) (if window-system (list tool-bar-map)))) ;; redo's menu-bar entry
Another comment: the version number in the comment is 1.15, but the variable “redo-version” is still set to 1.14.