Re: How to define xref-find-definitions for a new mode?

[Eli Zaretskii]

> From: Marcin Borkowski <mbork@mbork.pl>
> Cc: help-gnu-emacs@gnu.org
> Date: Mon, 11 Jun 2018 05:22:26 +0200
> 
> >> > (Btw, doesn't it already work?  Etags is an existing back-end for
> >> > Xref, and 'etags' the program already supports TeX and its
> >> > derivatives, so it is able to create TAGS tables for LaTeX files.)
> >>
> >> Well, possibly, but I'd like it to work like for Elisp or JavaScript,
> >> without a TAGS table.
> >
> > Is this likely to happen?  Lisp and JavaScript know where to find
> > functions and variables because they keep that information as part of
> > defining them.  I don't think TeX does anything similar, does it?
> 
> Why couldn't it (at least in theory)?  If etags can do it, why not
> Emacs?

You said "no TAGS", so do you mean you want to rewrite the TeX part of
etags in Lisp, and make that run in real-time, when the user types
"M-."?  Won't this be too slow.

> Also, I'm not sure JS does that.

Me neither, but it was you who mentioned JS, not me ;-)

> >> Also, I want it to go to \label when on \ref, to \bib / \bibitem
> >> when on \cite etc.
> >
> > Are you sure it doesn't work already?  E.g., if \label is tagged, then
> > "M-." on the tag's name at \ref should go to the label's definition.
> 
> Well, apparently it doesn't without the TAGS file.  And even with it,
> I couldn't make it to work.  Also, amsrefs is not suppported.

Then my suggestion would be to extend etags to support that.  That way
you won't be starting from scratch.