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

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

Thanks Karthik,

I made that change too and pushed onto the branch.

Eric


On 1/17/21 11:53 PM, Karthik Chikmagalur wrote:
> Hi Eric,
>
> The `matlab-local-xref` backend is quite useful, thank you for taking
> the time to go through it. I did notice something in this function:
>
> (defun matlab-shell-xref-activate ()
>    "Function to activate xref backend.
> Add this function to `xref-backend-functions' for matlab shell to
> use xref to find function and variable definitions."
>    (and (member major-mode '(matlab-mode matlab-shell-mode org-mode))
>         (matlab-shell-active-p)
>         'matlab-shell))
>
> The test for major-mode is unnecessary since the xref backend is only
> loaded when matlab-mode is activated. Even if you decide to leave it in
> the reference to `org-mode' is completely superfluous. This is some
> debug code that I forgot to take out before I submitted the patch. (The
> same applies to the function `matlab-local-xref-activate'.) So we just
> need
>
> (defun matlab-shell-xref-activate ()
>    "Function to activate xref backend.
> Add this function to `xref-backend-functions' for matlab shell to
> use xref to find function and variable definitions."
>    (and (matlab-shell-active-p)
>         'matlab-shell))
>
> Karthik
>
> Eric Ludlam <eri...@gm...> writes:
>
>> 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
>>>
> .