bug#47455: 27.1; bibtex mode - citation key generation - non-ascii characters

["Roland Winkler" <winkler@gnu.org>]

On Tue May 18 2021 Lars Ingebrigtsen wrote:
> Brian Elmegaard <be@mek.dtu.dk> writes:
> 
> > Using C-c C-c in a bibtex cleans the entry and generates a citation key.
> > If the author name includes non-ascii characters these are included in
> > the key, even though BibTeX does not accept this.
> 
> Is this the case for all versions of BibTeX?

I believe the problem lies here already in BibTeX itself, that is,
BibTeX [like conventional (La)TeX] does not like non-ascii
characters anywhere, not in the key nor anywhere else.

Of course, there is biblatex and also new versions of (La)TeX that
can handle non-ascii characters.  But that's a separate story.

> > For example:
> >
> > @Article{äöü21,
> >   author =          {æøå äöü},
> 
> I guess Emacs could an asciification of some sort here, but I'm
> not sure there's any that's universally accepted?

The default of the user variable bibtex-autokey-transcriptions
handles "LaTeX non-ascii" characters like \"a.  You can customize
these rules to your liking.

I vaguely remember an old thread that started from the very question
raised here and expanding on how asciification can be encapsulated
in some generic piece of elisp code.  But I cannot find it anymore
and I do not know either whether this would be possible at all.  I
believe, everyone agrees on asciification of German umlaute like

  ä -> ae

But beyond that, I do not know how to do this satisfactorily.