Use popup window for hover preview

[mattn]

[prabirshrestha]

Seems like there is a similar PR but for neovim at #395. Would be good if we could get it working for vim8 and neovim.

1. Is it possible to focus on the popup window so that I can copy doc samples?
2. Should we add a flag so that users can decide the preference let g:lsp_hover_ui = ['floating_window', 'preview']
3. Allow to add custom keybindings to close the preview window.

//cc @jerdna-regeiz

[prabirshrestha]

Seems like doesn't correctly handle when the popup window is very large. This is also another scenario where I would need to focus on the popup window and scroll.

This is using https://github.com/theia-ide/typescript-language-server in cli.ts

[jerdna-regeiz]

I'll check it out tomorrow and see if I can easily integrate it with #395 keeping all features.

[mattn]

Is it possible to focus on the popup window so that I can copy doc samples?

No, current implementation of popup on vim8 does not provide way to give focus.

Should we add a flag so that users can decide the preference let g:lsp_hover_ui = ['floating_window', 'preview']

Okay, will do in later.

Allow to add custom keybindings to close the preview window.

This too. Thank you.

[jerdna-regeiz]

I have integrated it into #395, thanks to @mattn. Feel free to join me on a combined approach!
But sadly mattn is right... there will be no focus at all. I guess the feature is pushed by other GUI development and relies on mouse to copy =(

[prabirshrestha]

Let us use the PR by @jerdna-regeiz in #395 for discussions as it works for both vim8 and neovim.

[prabirshrestha]

Merged #395 in favor of this PR. Thanks.