bug#28403: 25.2; find-tag works, but xref-find-definitions

[Eli Zaretskii]

> Cc: 28403@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Mon, 11 Sep 2017 00:43:51 +0300
> 
> > Dmitry, how about providing a more user-friendly customization to that
> > effect?  As a "fire escape"?
> 
> We can turn etags-xref-find-definitions-tag-order into a defcustom, with 
> descriptions of what every possible element means.

I rather had in mind a variable with a few simple values, and a :set
function which would put what's needed into
etags-xref-find-definitions-tag-order.  IOW, hide the complexity from
the UI.

> 1) I have hard time imagining how we're going to have descriptions for 
> both tag-exact-match-p and tag-implicit-name-match-p that are different 
> and make sense to the user.

Simple values with solve that. For starters, we could use just 2:
'exact' and 'fuzzy'.

> 2) The user will have to find out about 
> etags-xref-find-definitions-tag-order first anyway.

Will be solved by having the defcustom under a more descriptive name.

And since this is a "fire escape", it will be needed relatively
rarely.  The point is to have it, so we could point users to it.

> Or we could add a custom variable to xref with a higher-level meaning... 

Yes.

> that would require support from backends, then.

Why?