Re: undoing changes automatically

["Roland Winkler" <Roland.Winkler@physik.uni-erlangen.de>]

On Wed Jan 9 2008 Stefan Monnier wrote:
> > I looked at the code of cancel-change-group.  It's not clear to me
> > what "Undoing to some unrelated state" means.  I'd expect that
> > atomic-change-group should not produce any errors by itself.
> 
> I guess the message means that cancel-change-group couldn't find the
> path (through undo entries) going from the current state to the
> original state.  More specifically, it means that the current undo-log
> does not contains as one of its nthcdr the head of the original
> undo logs.  That might be the case if the changes to undo are too
> numerous and the undo-log has been truncated to the point where the
> undo-info needed to revert the change are not present any more.

I thought of something like this, though I couldn't phrase it as
nicely and accurately as you did it  :-)

Inside atomic-change-group, bibtex-format-entry does its job for one
BibTeX entry at a time. So typically it operates on 10 to 15 lines
of plain text (~ 300 characters), and it adds about 100 elements to
the undo list. I'd expect that these are still sufficiently small
numbers for atomic-change-group.

I checked in the new code of bibtex.el that uses atomic-change-group.
So we'll see if anybody else runs into similar problems when using
bibtex-mode.

Roland