Hi Dmitry and Arash,

Here's my third attempt at a working xref backend for TeX. I'll try
quickly to summarize what's in it:

1. I've modified etags so that it creates findable tags for as many
different sorts of TeX construct as possible, including those written
in the new expl3 syntax. I've now removed the escape character from
the tag names, as this simplifies code all around.

2. 4 of the 6 xref backend functions just call the etags backend.

3. xref-backend-identifier-at-point is modified to provide new regexps
for delineating TeX symbols, and there's also code to cope with expl3
constructs slightly differently in M-? than in the other two main xref
commands.

4. xref-backend-references is a wrapper for the standard backend, the
wrapper doing two things: first, it tries to accumulate as many file
extensions for the current major-mode as emacs knows about, and second
it creates a bespoke syntax-propertize-function for strings that
aren't entirely composed of symbol or word characters. It applies this
function to file-visiting buffers and lets xref apply it in the
*xref-temp buffer, though I had to add a one-liner in xref.el to fix
what I believe is a minor bug there preventing syntax-propertize from
doing its work when the temp buffer holds text from a new file. (I can
provide a recipe for this if you want.)

5. Slightly unrelatedly, I've added new syntax-propertize-rules to
latex-mode so that expl3 constructs with the underscore aren't
fontified as subscripts, which makes such code unreadable. I'm happy
to split this off as another patch.

All comments gratefully received, and thanks,

David.

On Mon, 22 Apr 2024 at 14:06, Arash Esbati <arash@gnu.org> wrote:
>
> David Fussner <dfussner@googlemail.com> writes:
>
> > Thanks for the clarifications. If you look at the current patch to
> > tex-mode.el, there's one function call added to TeX-mode-hook, mainly
> > for my own testing purposes, but no matter what the final patch looks
> > like it should only similarly require a single function call in an
> > AUCTeX hook to activate the new xref code there, along with one in
> > tex-common-initialization for the in-tree modes. If and when all
> > parties are satisfied by the patch I'll certainly be in touch with you
> > to find out how you'd prefer to handle activating it (or not) in
> > AUCTeX. The current state of affairs is a convenience for me and for
> > anyone else who cares to test the code.
>
> Hi David,
>
> I justed wanted to come back on this report and ask if there is any
> progress?  It would be nice to get Xref working within TeX buffers.
>
> TIA.  Best, Arash