bug#53749: 29.0.50; [PATCH] Xref backend for TeX buffers

[Dmitry Gutov]

On 21.02.2022 11:48, David Fussner wrote:
> Sometimes using a search string
> that had been put through regexp-quote was wrong, as when a user
> provided their own regexp in the minibuffer, so in both those cases I
> provided fallbacks to a different search in case the default search
> came up empty.  I couldn't see how to do this without a new backend.

One way to deal with that is to treat all user inputs as regexps there. 
Perhaps some will have to be more verbose that ideal, but as long as the 
user is familiar with the regexp syntax, the behavior will be both 
powerful and predictable.

> 2.  A package like biblatex creates what amounts to a separate
> namespace using the \newbibmacro mechanism, so pretty much every
> biblatex style has both a \cite command and a cite bibmacro, and I
> wanted to allow emacs to differentiate between them when using
> xref-find-definitions.  Because users of the etoolbox package (like
> biblatex) may well mix commands with and without the escape char "\",
> I also provided a variable to allow users to find when a \command is
> called using \csuse{command} instead.  Again, this required a fallback
> search (see xref-backend-definitions) which I couldn't see how to
> provide without a new backend.

Could those be be disambiguated when the tags are scanned, instead? Then 
the user will tailor their input to find the one or the other.

Or if we want more fuzzier matching, perhaps creating mode-specific 
values of etags-xref-find-definitions-tag-order could help.