fxtv@geocub.UUCP (Vaillant) (04/15/88)
I would appreciate help about the undo mechanism of editors such as emacs. What are the basic tools used to implement this? Are they efficient? Francois-Xavier Testard-Vaillant UUCP: uunet!mcvax!inria!fxtv
bd@hpsemc.HP.COM (bob desinger) (04/22/88)
Francois-Xavier Testard-Vaillant (fxtv@litp.UUCP) writes: > I would appreciate help about the undo mechanism of editors such as > emacs. What are the basic tools used to implement this? Are they > efficient? For GNU Emacs, see dist-*/src/undo.c and dist-*/src/undo.h. The code there uses structs, so it's somewhat hairy. It copies data using the extremely fast bcopy() routine, so it's quite efficient. (Remember that premature optimization is the root of all evil---don't make it fast before you make it right.) -- bd
tmoody@sjuphil.uucp (T. Moody) (05/22/91)
Is there any PC-based version of emacs that has Undo? My own view is that an editor that supports regular expression search and replace needs to have undo, since reg. exps. make it possible to screw up files in ways that are not readily reversible manually. I know that Micro-emacs does not (yet) have undo, but I don't know about the latest version of Freemacs, and I've never seen Jove. -- Todd Moody * tmoody@sjuphil.sju.edu "In what furnace was thy brain?" -- William Blake