xref and GNU Global?

xref and GNU Global?

[Nicolas Petton]

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Hi,

I find GNU Global to be far superior to etags or ctags.  Is there any
plan to have support for it in xref.el? (Or maybe there is and I missed
it).  Else I might start working on that.

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: xref and GNU Global?

[Stephen Leake]

Nicolas Petton <nicolas@petton.fr> writes:

> I find GNU Global to be far superior to etags or ctags.  Is there any
> plan to have support for it in xref.el? (Or maybe there is and I missed
> it).  Else I might start working on that.

Currently there is support for GNU Global in Semantic, and xref has some
hooks into Semantic.

So please post your specific use cases, and we can discuss gettting
those to work via xref/Semantic.

-- 
-- Stephe

Re: xref and GNU Global?

[Dmitry Gutov]

On 08/19/2015 12:02 PM, Nicolas Petton wrote:

> I find GNU Global to be far superior to etags or ctags.  Is there any
> plan to have support for it in xref.el? (Or maybe there is and I missed
> it).  Else I might start working on that.

I would approach it from a different direction: by adding xref support 
to ggtags (in GNU ELPA).

Re: xref and GNU Global?

[Stefan Monnier]

> I find GNU Global to be far superior to etags or ctags.  Is there any
> plan to have support for it in xref.el? (Or maybe there is and I missed
> it).

Yes.  IIRC the plan is to wait for Nicolas Petton to start working on it.


        Stefan

Re: xref and GNU Global?

[Nicolas Petton]

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Stephen Leake <stephen_leake@stephe-leake.org> writes:

> Nicolas Petton <nicolas@petton.fr> writes:
>
>> I find GNU Global to be far superior to etags or ctags.  Is there any
>> plan to have support for it in xref.el? (Or maybe there is and I missed
>> it).  Else I might start working on that.
>
> Currently there is support for GNU Global in Semantic, and xref has some
> hooks into Semantic.
>
> So please post your specific use cases, and we can discuss gettting
> those to work via xref/Semantic.

I haven't used xref.el at all yet, so I don't have any use case, but
I'll try it and tell you!

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: xref and GNU Global?

[Nicolas Petton]

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Dmitry Gutov <dgutov@yandex.ru> writes:

> On 08/19/2015 12:02 PM, Nicolas Petton wrote:
>
>> I find GNU Global to be far superior to etags or ctags.  Is there any
>> plan to have support for it in xref.el? (Or maybe there is and I missed
>> it).  Else I might start working on that.
>
> I would approach it from a different direction: by adding xref support 
> to ggtags (in GNU ELPA).

I meant in general, with ggtags or something else, but yes, I'd probably
do it this way too.

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: xref and GNU Global?

[Nicolas Petton]

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Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> I find GNU Global to be far superior to etags or ctags.  Is there any
>> plan to have support for it in xref.el? (Or maybe there is and I missed
>> it).
>
> Yes.  IIRC the plan is to wait for Nicolas Petton to start working on
> it.

Hmm, right.  First I'll have a look at what semantic & xref already have
to offer :)

Cheers,
Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

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Re: xref and GNU Global?

[Stephen Leake]

Nicolas Petton <nicolas@petton.fr> writes:

> Stephen Leake <stephen_leake@stephe-leake.org> writes:
>
>> Nicolas Petton <nicolas@petton.fr> writes:
>>
>>> I find GNU Global to be far superior to etags or ctags.  Is there any
>>> plan to have support for it in xref.el? (Or maybe there is and I missed
>>> it).  Else I might start working on that.
>>
>> Currently there is support for GNU Global in Semantic, and xref has some
>> hooks into Semantic.
>>
>> So please post your specific use cases, and we can discuss gettting
>> those to work via xref/Semantic.
>
> I haven't used xref.el at all yet, so I don't have any use case, but
> I'll try it and tell you!

The use case is for Gnu Global, not for xref.

Give an example of how you currently use Gnu Global, and we can see if
xref can (or even should) support that.

-- 
-- Stephe

Re: xref and GNU Global?

[Eli Zaretskii]

> From: Nicolas Petton <nicolas@petton.fr>
> Date: Wed, 19 Aug 2015 23:28:55 +0200
> 
> Dmitry Gutov <dgutov@yandex.ru> writes:
> 
> > On 08/19/2015 12:02 PM, Nicolas Petton wrote:
> >
> >> I find GNU Global to be far superior to etags or ctags.  Is there any
> >> plan to have support for it in xref.el? (Or maybe there is and I missed
> >> it).  Else I might start working on that.
> >
> > I would approach it from a different direction: by adding xref support 
> > to ggtags (in GNU ELPA).
> 
> I meant in general, with ggtags or something else, but yes, I'd probably
> do it this way too.

If we want GNU Global support be part of the core functionality, and
consider it as replacement for etags, then its support should be in
core Emacs, not on ELPA.

Re: xref and GNU Global?

[Nicolas Petton]

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Stephen Leake <stephen_leake@stephe-leake.org> writes:

> Give an example of how you currently use Gnu Global, and we can see if
> xref can (or even should) support that.

I use GNU Global (with ggtags.el) to find references or definitions of
functions/methods within a project, using M-. and M-, to jump back.

Nico

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Re: xref and GNU Global?

[Stephen Leake]

Nicolas Petton <nicolas@petton.fr> writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>>> I find GNU Global to be far superior to etags or ctags.  Is there any
>>> plan to have support for it in xref.el? (Or maybe there is and I missed
>>> it).
>>
>> Yes.  IIRC the plan is to wait for Nicolas Petton to start working on
>> it.
>
> Hmm, right.  First I'll have a look at what semantic & xref already have
> to offer :)

One approach is to use what semantic currently has for gnu global;
that's in emacs/lisp/cedet/semantic/db-global.el. I'm not clear if all
of that is accessible via the xref interface yet.

I suspect semantic/db-global.el provides the same functionality as
ggtags, possibly without as much UI; the current design goal is for xref
to be the UI for semantic cross-reference features.


Another approach is to try to integrate ggtags with xref.

There are two major differences between ggtags and xref:

xref provides a way to dispatch, in order to choose the right tool.
ggtags apparently has another way.

In addition, ggtags uses compilation mode to display the results; xref
has a different display by default (the display function can be changed
by a hook).

The first step is to decouple the gnu global code into "UI", "accumulate
reference" and "display references" sections (that may be done already;
I didn't actually look).

Then set xref-find-function and a few other things, to have the xref UI
dispatch to the Gnu Global "accumulate references" code.

Then you can either add new code that produces xref-locations, or set
the hook that changes the display function for xref.

-- 
-- Stephe

Re: xref and GNU Global?

[Eric Ludlam]

On 08/21/2015 08:37 AM, Stephen Leake wrote:
> Nicolas Petton <nicolas@petton.fr> writes:
>
>> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>
>>>> I find GNU Global to be far superior to etags or ctags.  Is there any
>>>> plan to have support for it in xref.el? (Or maybe there is and I missed
>>>> it).
>>>
>>> Yes.  IIRC the plan is to wait for Nicolas Petton to start working on
>>> it.
>>
>> Hmm, right.  First I'll have a look at what semantic & xref already have
>> to offer :)
>
> One approach is to use what semantic currently has for gnu global;
> that's in emacs/lisp/cedet/semantic/db-global.el. I'm not clear if all
> of that is accessible via the xref interface yet.
>
> I suspect semantic/db-global.el provides the same functionality as
> ggtags, possibly without as much UI; the current design goal is for xref
> to be the UI for semantic cross-reference features.

Global support from cedet/semantic comes from a few different places. 
The core interface is a few calls in cedet-global.el.  Helpful for 
getting some raw data.

The semantic/db-global.el is for using GNU Global as a database backend. 
  Stand-alone, it is not useful.  With Semantic and it's generic 
database system, it provides a way to find symbol declarations across a 
project.  You would use this if you wanted to write or use an existing 
tool using semantic's tag finding APIs to find declarations. 
semantic-complete-jump is an example that uses that.  The nice thing 
about semantic's database system is it can mix multiple tools together, 
for example global for project wide, and Semantic's parser system for 
buffers you are editing that global doesn't know about yet.

semantic/symref/global.el is another place with global support.  This 
one is pretty simple as far as running and parsing output for use with 
the semantic symref searching system.   This tool is useful for finding 
references, and also providing other tag information along with the 
different hits.


Eric