Tagging Fortran variables

Tagging Fortran variables

[Christopher Howard]

Hi, part of my work is researches/troubleshooting in a big collection of old Fortran code files. I want to be able to use the xref tools to help me. However, it seems that etags does not tag Fortran variables, which 99% of the time is what I am interested in. It looks like there is a way to tag anything you want using regexps, so I was looking at the fortran.el code to see if maybe I could find the magic regexp for this. But there is a lot going on here in fortran.el that I don't understand yet and I am wondering if somebody might be able to help me figure this out.

-- 
📛 Christopher Howard
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Re: Tagging Fortran variables

[Marcus Harnisch]

On 06/08/2024 00.25, Christopher Howard wrote:
> Hi, part of my work is researches/troubleshooting in a big collection of old Fortran code files. I want to be able to use the xref tools to help me. However, it seems that etags does not tag Fortran variables, which 99% of the time is what I am interested in. It looks like there is a way to tag anything you want using regexps, so I was looking at the fortran.el code to see if maybe I could find the magic regexp for this. But there is a lot going on here in fortran.el that I don't understand yet and I am wondering if somebody might be able to help me figure this out.

You may want to try Global (https://www.gnu.org/software/global/)
This in turn depends on Universal Ctags (https://ctags.io/),
and Pygments (https://pygments.org/)

On the Emacs side, I am using ggtags 
(http://elpa.gnu.org/packages/ggtags.html)

This combination served me well in many projects.

Re: Tagging Fortran variables

[Joel Reicher]

Christopher Howard <christopher@librehacker.com> writes:

> Hi, part of my work is researches/troubleshooting in a big 
> collection of old Fortran code files. I want to be able to use 
> the xref tools to help me. However, it seems that etags does not 
> tag Fortran variables, which 99% of the time is what I am 
> interested in. It looks like there is a way to tag anything you 
> want using regexps, so I was looking at the fortran.el code to 
> see if maybe I could find the magic regexp for this. But there 
> is a lot going on here in fortran.el that I don't understand yet 
> and I am wondering if somebody might be able to help me figure 
> this out.

Have you tried using xref in eglot? It will attempt to use the 
fortls fortran language server.

(I haven't tried this myself, but I've had good experiences with 
eglot and language servers in general.)

Cheers,

        - Joel

Re: Tagging Fortran variables

[Christopher Howard]

Do you know if Gnu Global tags variables as well? In the online documentation I'm only seeing functions, macros, structs, and classes mentioned, though I suppose it varies from language to language.

-- 
Christopher Howard

Re: Tagging Fortran variables

[Marcus Harnisch]

On 06/08/2024 18.31, Christopher Howard wrote:
> Do you know if Gnu Global tags variables as well? In the online documentation I'm only seeing functions, macros, structs, and classes mentioned, though I suppose it varies from language to language.
> 

Global comes with a few built-in parsers (no Fortran it seems). In any 
case I'd recommend to take advantage of delegating to ctags/Pygments, 
whose parsers are most likely more up-to-date. It looks like ctags' 
Fortran parser defines a tag type for variables. Give it a try.

Re: Tagging Fortran variables

[Christopher Howard]

> Have you tried using xref in eglot? It will attempt to use the fortls
> fortran language server.

I'm not familiar with eglot, but I see there is a package for it in Guix, so I could look into that. It does not appear that there is yet a package for fortls, but presumably I can get it installed through pip, which I see is already installed on my system.

-- 
Christopher Howard

Re: Tagging Fortran variables

[Christopher Howard]

Eglot already part of Emacs, it appears...? I see an info manual already installed so I will read through that.

-- 
Christopher Howard

Re: Tagging Fortran variables

[Joel Reicher]

Christopher Howard <christopher@librehacker.com> writes:

> Eglot already part of Emacs, it appears...? I see an info manual 
> already installed so I will read through that.

I strongly recommend it. If fortls is good, the results in Emacs 
will be outstanding, because eglot - roughly speaking - provides a 
new backend to existing Emacs frontends, and so it's a switch with 
a seamlessness I haven't seen very often in any software.

One gotcha though (in my opinion!) is the 
":documentOnTypeFormattingProvider" server capability; you may 
want to disable that (by adding it to 
"eglot-ignored-server-capabilities") if you have a non-LSP based 
solution you prefer (such as treesitter).

Cheers,

        - Joel