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

[Dmitry Gutov <dgutov@yandex.ru>]

On 9/11/17 5:43 PM, Eli Zaretskii wrote:

>>>> that would require support from backends, then.
>>
>> To make "fuzzy" work.
> 
> It would be good to have other back-ends support that, but I don't
> think it's a must.  First, no one said all the back-ends must
> distinguish between the two modes; it could even be that only one
> makes sense for some language.

How will we define that it "makes sense"?

There are two ways it could work:

- Like etags, try to match all words on the same line as the legitimate 
definitions. For most backends, this will simply be impossible (for 
those that use a concise index instead of a flat list of strings). E.g., 
the elisp backend can't implement that.

- Allow substring matching for definition names? But xref-find-apropos 
already lets you do that.

> And second, I'm guess that this new
> method will only be useful to those who are accustomed to etags.
> 
> So I think we could add this with only the etags back-end support for
> now, and extend it later to other back-ends if needed.

Should it be a defcustom in etags.el, then? That's not far from what I 
suggested in the first place.

I hesitate to add a defcustom to xref.el that will only affect etags.