Re: Changing of line format and undo

[Lennart Borgman]

David Kastrup wrote:
> Lennart Borgman <address@hidden> writes:
>
>   
> > David Kastrup wrote:
> >     
> > > Lennart Borgman <address@hidden> writes:
> > >
> > >   
> > >       
> > > > Eli Zaretskii wrote:
> > > >     
> > > >         
> > > > > > Date: Wed, 21 Jun 2006 00:15:17 +0200
> > > > > > From: Lennart Borgman <address@hidden>
> > > > > >
> > > > > > If you change line endings this change is not saved to undo. Is
> > > > > > this the expected behaviour?
> > > > > >             
> > > > > >             
> > > > > If you mean "C-x RET f", then it doesn't really change anything.  It
> > > > > just sets a buffer-local variable to some value.  So there's nothing
> > > > > to undo.
> > > > >         
> > > > >           
> > > > That is an internal Emacs perpective. From a users point of view there
> > > > is truly a change. If you for example change the line endings the file
> > > > will be saved with this new line endings.
> > > >
> > > > BTW should not changes of this kind also set the buffer to modified?
> > > >     
> > > >         
> > > What makes you think they don't?
> > >
> > >   
> > >       
> > Test this for example:
> >
> >    (defun test-set-eol()
> >      (interactive)
> >      (let* ((coding buffer-file-coding-system)
> >             (new-coding (coding-system-change-eol-conversion coding 2)))
> >        (setq buffer-file-coding-system new-coding)))
> >     
>
> Very funny.  setq most certainly does not trigger effects like a
> changed buffer modification flag.  But setq is not a user-level
> command.  Here is one that is:
>   
Thanks, you are right ;-) Now I see what Eli meant. I still believe that 
everything that can result in changing an external file should go into 
the undo history but this is really a corner case of course.