bug#22947: 25.0.92; xref-find-definitions fails for Perl & etags

[Dmitry Gutov <dgutov@yandex.ru>]

On 03/11/2016 10:04 AM, Eli Zaretskii wrote:

> Etags never had these features, so you are asking for enhancements.  I
> suggest to file a separate wishlist bug report with these requests,
> and maybe Someone will implement them at some point.

There's nothing to implement in Emacs, both of these scenarios should 
work already. They just need the presence of qualified names in the tags 
table.

And allowing the output of qualified+unqualified, in etags, doesn't seem 
like a huge job to me.

> Note that adding such a feature would mean extending the generation of
> class-qualified names to all the languages which have a notion of a
> class or a package, so it's not a small job, and requires to have a
> good understanding of many languages.

We can perfectly well choose to support this feature only for a few 
languages. It's better than nothing.

Here's the relevant excerpt from ctags's manpage:

"""
q

Include an extra class-qualified tag entry for each tag which is a 
member of a class (for languages for which this information is 
extracted; currently C++, Eiffel, and Java). The actual form of the 
qualified tag depends upon the language from which the tag was derived 
(using a form that is most natural for how qualified calls are specified 
in the language). For C++, it is in the form "class::member"; for Eiffel 
and Java, it is in the form "class.member". This may allow easier 
location of a specific tags when multiple occurrences of a tag name 
occur in the tag file. Note, however, that this could potentially more 
than double the size of the tag file.
"""

> Personally, I'd like first to see if the current implementation of
> etags + xref gives good results, before considering enhancements.
> Without seeing user responses, we will never know how important these
> features are.

Ultimately, it's your choice, of course.