I'm not real familiar with the mechanics of the undo list, but couldn't the previous file contents be stored only on disk, as a temporary file, and the value in the undo list be just a pointer to that file instead of the file contents?
It would be conceivable to store old undo-list contents in files. 15 years ago I wanted to implement that in Emacs. Nowadays it seems less important, because memory is big enough to hold more undo list data than in the past. It's only for something like this that one would think of wanting to do that. _______________________________________________ Emacs-devel mailing list Emacs-devel@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-devel