Re: eglot's interface for major modes

[Sebastian Poeplau]

>> I may be mistaken, but my understanding of ff-other-file-alist is that
>> it needs to be set to a mapping between file extensions of specification
>> and implementation files; whatever the value, ff-find-other-file will
>> use the algorithm in find-file.el.
>
> Even the algorithm can be redefined.  The latest version of the
> documentation of variable ff-other-file-alist explains the details.

Interesting! I checked the doc string in Emacs 28 before writing my
earlier message; it seems that a lot has changed since then :)

> Eglot-x contains a possibly overly complicated example that also
> delegates the ff-other-file functionality to LSP servers.
> <https://github.com/nemethf/eglot-x>
>
> But it's basically
>
>   (setq-local ff-other-file-alist '(("*.ext ext-mode--ff-other-file)))

That would indeed be a good fit! I'll have a look.