bug#61072: How to change the length of the separation lines in eldoc, used by eglot?

[João Távora]

On Tue, Feb 21, 2023 at 5:11 PM Felician Nemeth
<felician.nemeth@gmail.com> wrote:

> So the LSP server sends "---\n".  gfm-view-mode turns these three dashes
> into a long separation line, which is then displayed by eldoc-box.
> Neither gfm-view-mode nor eldoc-box is a part of Emacs or available from
> GNU ELPA.  I'm therefore tempted to say that debbugs is not the right
> place for this bug report.
>
> However, when Eglot calls gfm-view-mode in eglot--format-markup the
> window-width probably equals to the width of the window containing the
> user's source code and eldoc-box seems to display the documentation in a
> narrower window.  So maybe it would help if Eglot allowed the users to
> run a custom function instead of calling gfm-view-mode in
> eglot--format-markup.

Yes, I see the problem.  Thanks for describing Felicián.

But I don't think your suggestion is the correct way to tackle it.

Rather,  Eglot should add a markdown-capable element to
eldoc-display-functions and hint in the documentation item
produced by Eglot's eldoc-documentation-functions that that item
has a markdown version (it may also have a plaintext version
alongside),  taken directly from the LSP source. The new function
would then render the item appropriately.

Then users and other modes such as eldoc-box can also add things to
eldoc-display functions, read the hints (if they support them)
and do whatever they think is more suitable with the rich/poor
documentation item.

This is in principle already fully supported by the ElDoc
infrastructure, but needs someone to experiment with it (and
potentially find limitations in ElDoc, which I can help plug).

João