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

[Lars Ingebrigtsen <larsi@gnus.org>]

"Roland Winkler" <winkler@gnu.org> writes:

> One can also instruct font-lock to use for non-ascii characters
> something like font-lock-warning-face (based on a user option for
> enabling this behavior).

Sounds like a good idea.

> However this fails with something like the unicode character
> 'ZERO WIDTH SPACE' (which has fooled me occassionally in the very
> context we are discussing here).  Is it possible to instruct emacs
> to make such "hidden characters" more easily visible, say by using
> some display property?

I vaguely remember a discussion about this not too long ago, but I can't
find it now.

All the other space "special" space characters, like NON-BREAKING SPACE
and the like, are fontified specially by default in Emacs 28.  But the
point of ZERO WIDTH SPACE is that it takes no room, which makes it
difficult to fontify.  :-)

But bibtex could apply a special display property here, or fontify the
surrounding characters in a special way.

> The fontification could also be encapsulated in a minor mode that
> one could use for \(Bib\|La\)?TeX files.
>
> Maybe such a minor mode exists already and I am right now
> reinventing the wheel?

I can't recall any such minor mode.  Anybody else?

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