bug#50202: bibtex-mode: unescaped dollar sign in file field leads to wrong highlighting

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>>> - bibtex-mode enabled,
>>> - and a BibTeX entry which has as value for file field a path that
>>> has dollar sign ~
>>> /path/to/file $ name.ext~
>>>
>>> bibtex-mode doesn't recognizes that the dollar sign is verbatim for
>>> the file field, leading to wrong highlighting.
>>
>> This behaviour is still present in Emacs 29.  Perhaps Roland has some
>> comments; added to the CCs.
>
> A field "file" is, I believe, not part of standard BibTeX.  So the above
> is somewhat pushing the limits of BibTeX mode.

I think the report/problem would be the same if there was a $ in a URL, tho.

> From a more practical perspective, I need to say that the above problem
> reaches the limits of my knowledge of how font-lock works in general and
> how it deals with the (La)TeX delimiter "$" in particular.

It doesn't deal with $ very well, indeed.

But I wonder how important it is for `bibtex-mode` to try and recognize
the (La)TeX meaning of the $ character.
Maybe we should just give $ the punctuation syntax in the syntax-table.


        Stefan