Automatically displaying function documentation (i.e. LspHover) while typing?

[fgimian]

Hey there, thanks so much for your amazing work on this plugin for vim 😄

When using LSP in Sublime Text, I can easily see function documentation in a little tooltip as I type:

When using vim-lsp and vim, I can see the suggestions as I type:

However, this popup disappears when I open my brackets to type the parameters. Is there a way to keep this displayed and highlight which parameter I'm currently entering like Sublime Text does above?

Further to this, it seems the only way to see documentation once I type the opening bracket is to use the :LspHover command, which gives me this:

Is there a way to display this information automatically as you are typing?
I also noticed that this documentation would disappear after I started typing my parameter names in the brackets too. Not sure if there's a way to avoid that happening.

I attempted to explicitly set completeopt to include preview but that didn't seem to help.

Any help is greatly appreciated
Fotis

[fgimian]

So I've managed to get one step closer. I had to do the following to see automatic previews of functions:

let asyncomplete_auto_completeopt = 0
set completeopt=menuone,noinsert,noselect,preview

It seems that set completeopt+=preview simply won't work because completeopt is completely overridden by asyncomplete.vim. I'm not sure if this is a bug?

So I guess the main questioning remaining is, is there a way to see the function signature or preview window while typing function arguments? vim-go seems to have attempted this 😄

Cheers
Fotis

[fgimian]

So unfortunately the solution I place above doesn't show full documentation that LspHover does.

e.g. here is the preview window

And here's LspHover:

Clearly I'm missing something here 😄

Any help is greatly appreciated
Fotis

[mikew]

Looks like textDocument/signatureHelp exists in LSP. There was even an issue created here for it, but the author closed it. #53

vim-lsc seems to have support for it: https://github.com/natebosch/vim-lsc/blob/c6d088d86cf485567cdafcf451c8b265b1620efe/autoload/lsc/signaturehelp.vim#L17-L54

[fgimian]

Looks like textDocument/signatureHelp exists in LSP. There was even an issue created here for it, but the author closed it. #53

vim-lsc seems to have support for it: https://github.com/natebosch/vim-lsc/blob/c6d088d86cf485567cdafcf451c8b265b1620efe/autoload/lsc/signaturehelp.vim#L17-L54

Thanks a lot for the reply. I also found deoplete does it well, so I may try that again too.

So far vim-lsp has been my favourite LSP plugin so would be lovely if it supported this functionality in future.

Kindest Regards
Fotis

[prabirshrestha]

MenuPopupChanged neovim/neovim#9616 and floating windows should allow this in the future. Will wait for it to stabilize first.

[mkwork]

@prabirshrestha, did you know that jedi-vim has this feature implementation? It's quite tricky and my vim coding skills are too low for this implementation generalization. But, may be you would like to have a look.

[prabirshrestha]

There is a discussion going on floating window. Will take time for vim to support it. Neovim support was merged this week. vim/vim#4063

I would rather wait for a proper floating window support and have something like this instead instead of hacks. I'm not a fan of the preview window as it flickers the buffer too much.

[mkwork]

It's implemented within conceal instead of preview windows or other echodoc style distractive workrarounds :) Yep it's dirty hack. But it works like a charm, just try it on any python helloworld.

[zorgick]

@prabirshrestha any news? Is it implemented already? Man, I am fascinated by your plugin and I don't want to move again to another autocompletion plugin, but I'm really in lack of this feature.

[paltom]

@prabirshrestha are you going to support this? Now that Vim has popup_create and CompleteChanged it should be possible to implement this. This feature works in coc.nvim but it lefts artifacts when changing completion items and I prefer your LSP plugin anyway.

[dezza]

I see that the popup triggers on the latter arguments as well

__________________popup_happens
function (arg1, <cursor>)

The only issue I see with this is the closing/reopening of the popup (slight distraction) and the lack of highlight on the "current" argument.

I guess the highlighting of current argument will take a little effort to implement.

If you want the signature always displayed you can do "echodoc.vim" similar behaviour by doing:

        echo get(l:contents, 0, '')

after line 80
https://github.com/prabirshrestha/vim-lsp/blob/master/autoload/lsp/ui/vim/signature_help.vim#L80