Languageclient-neovim: Support for alternative completion plugins.

[jordwalke]

It's unfortunate that LanguageClient-neovim requires python3 to achieve autocompletion in Vim (non-NeoVim). Would you consider adding support for other lighter weight completion plugins such as mucomplete?

[chenglou]

Is this the only part of this project that requires python3? Unfortunately some folks are still on 2, either because it's the macOS default or because of corporate constraints. Would be nice to see this happen =)

Otherwise, we're started recommending this project as the official Reason plugin for vim! https://github.com/reasonml-editor/vim-reason-plus

[autozimu]

Thanks for the suggestion.

I've used neovim for so long such that forgot the pain of using python3 plugin with vim.

[jordwalke]

For something as (imho) important as a LSP bridge from Vim, it would be great if Vim (at least Vim8) had a great experience. I have had good experiences with mucomplete (it's not async though - does that matter?)

[autozimu]

Being sync is not an blocker for supporting mucomplete.

In fact, the completion API can be used with vim omnifunc, which is a sync call, https://github.com/autozimu/LanguageClient-neovim/blob/master/doc/LanguageClient.txt#L40

[jordwalke]

So how much work is it to allow LanguageClient-neovim to work with mucomplete?

[autozimu]

Support mucomplete could be easily done.

Support vim + python2 will require some amount of work, especially since the dependency https://github.com/roxma/vim-hug-neovim-rpc is still not stable enough.

[jordwalke]

Sorry, could you catch me up - how is vim-hug-neovim relevant?

[jordwalke]

are there parts of LanguageClient-neovim that depend on python3 specifically?

[autozimu]

vim-hug-neovim is needed for support of vim, as this plugin makes use of neovim remote plugin feature, which is not supported by vim. vim-hug-neovim will fill that gap. If you are already using neovim, then it is not relevant.

I made a mistake taking this issue as request for support of vim + python2 specially. So my last few comments might not make sense at all. Sorry about that.

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For the support of mucomplete, as previously mentioned, work needed is minimal.

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As for the request of support python2 when using neovim, there will be quite some work, as this plugin does make assumption of python3 at the very first beginning,

1. neovim python-client might not need support authoring remote plugin for both python2 and python3 at the same time (needs verification)
2. type hints not understand by python2
3. encoding differences between python2 and python3. This is critical in communicate with language servers

The work is substantial. Not sure whether it worth the efforts or not.

[jordwalke]

I made a mistake taking this issue as request for support of vim + python2 specially

That is the case actually - I merely thought that the autocomplete plugin was the only issue blocking that.
(Though it might be good to support mucomplete just because it's a nice autocomplete plugin anyways)

[autozimu]

I'm not even sure if it is feasible of authoring plugin for both neovim and vim, and for both python2 and python3. If it is possible to support both neovim and vim, it probably requires a rehaul of this plugin, which might be better to reconsider the choice of python.

[autozimu]

Closing. See https://github.com/autozimu/LanguageClient-neovim/issues/35#issuecomment-350525383