Re: [Matlab-emacs-discuss] completion and goto-function in matlab-mode (Doom emacs)

[Eric L. <eri...@gm...>]

Hi Karthik,

Thanks for the update and explanation.

I finally had some time to sit with your code, try it out in a few 
situations, and teach myself how xref works.  I haven't had much 
opportunity to learn all the new stuff in eieio that it uses, so that 
was nice.

I created matlab-xref.el on the shellcomplete branch which includes a 
tweaked version of your code.
I included an xref engine that will do local symbol lookups for local 
functions and the like.  Combined, with the shell version, you can get 
to most places quickly.

I think this is a pretty good start. I've already found it changed the 
way I do navigation.  Very nice.

Eric


On 12/23/20 5:04 AM, Karthik Chikmagalur wrote:
> Hi Eric,
>
>> I did look at the elisp backend which it advertised as the prime
>> example.  That one is quite large compared to your patch.  Do you
>> think the below would expand out to be much larger?  I'm considering
>> if xref support would move into it's own file or not.
> The xref support for MATLAB in my patch is very short (relatively)
> because
>
> - I wrote it as a wrapper around `matlab-shell-which-fcn', which does
>    the heavy lifing of finding the function in question. Matlab-shell
>    already has support for jumping to definitions so I reused it. The
>    downside is that matlab-shell needs to be running for xref support to
>    work. This is not ideal, but the alternative is to write code to find
>    function definitions from scratch.
>
> - Only jump to definition is implemented. Two other xref functions:
>    `xref-backend-apropos' and `xref-find-references', are not implemented
>    at all. I want to look into adding these, but I'm not sure right now
>    how to go about it.
>
>> I also note that the elisp version doesn't use require for xref, and
>> your patch depends on the feature existing when the code loads.  I
>> think it does so via:
>>
>>      (declare-function xref-make "xref" (summary location))
>>
>> Will that work here too?
> I think `declare-function' keeps the byte-compiler from complaining and
> doesn't do much else. This should help here, though, and checking if
> xref is loaded should be unnecessary.
>
> In summary, a slightly modified version of this patch can be included as
> preliminary xref support for matlab-mode. It can be its own file if it's
> expected to be expanded in the future with `xref-find-references' and
> other functionality, and prehaps written in a way as to not require
> matlab-shell to be running.
>
> Attached is a patch (as a separate file) with some minor modifications
> from last time. For it to be integrated into matlab-mode, one other
> piece of configuration is needed:
>
>      (add-hook 'xref-backend-definitions #'matlab-shell-xref-activate)
>
> This needs to be added in the matlab-mode major mode definition in
> `define-derived-mode matlab-mode' in matlab.el.
>
> Karthik
>