[gentoo-dev] [RFC] NeoVim and vim-syntax

["Vadim A. Misbakh-Soloviov" <gentoo@mva.name>]

Currently, we have a situation, that there are two Vim's: "old" one (vim8) and 
NeoVim (for those who do not know: a fork of Vim with much and much more clean 
code, many neat features and so on).

Unfortunately, both of them have different runtimedirs: XDG ones for NeoVim 
and the ones you know for Vim8, while NeoVim is fully compatible with Vim's 
plugins, and epecially with vimscripts (like syntax definitions and ftdetect 
scripts).

On the other side, we have a bunch of packages in the portage tree, that have 
"vim syntax" support (use-flags, or direct vim-syntax packages), or even vim-
plugins.
All of them goes to `/usr/share/vim/vimfiles`, while correct path for NeoVim 
would be `/usr/share/nvim/site` (does not exist at the moment, but nvim checks 
for it).

So, that situation leads to impossibility to get all of that syntax definitions 
and plugins when user uses NeoVim.

As I said above, NeoVim supports Vim's plugins/scripts very well (although I 
didn't find any evidence of the opposite), so it is possible to fix that 
situation by many of "kludge" ways, including:

- implementing "nvim-syntax" (and `app-nvim/*`?) and duplicate all the 
installed files

- patching NeoVim source to include Vim's runtimedirs (incl. "after" dir),
// NeoVim upstream highly disagree with such way, if any

- patching VIMRUNTIME environment variable,

- making a wrapper,

- rewrite all the existing ebuilds to take nvim into account and force all 
newcomers to also take it,

- symlinking a directory,
// mostly bad way, since opposite plugin compatibility is not garanteed and 
users can install nvim-only plugins in the future

- making postinst hook to regenerate content of NeoVim's site-directory 
(maybe, by symlinking installed vim modules there)

or even:

- making eselect module for user to rule that.

Although, talking on eselect module, I've two visions of the situation:
a) it can be something like bashcomp module, where users can select which of 
installed vim modules they want to "enable" in NeoVim
or (better, imo) way:
b) it can be something like php module, where portage installs all the stuff 
in the location neither available to Vim nor NeoVim, and users selects which 
modules they enable for either implementation.

Module can be called something like "eselect-vim" or "eselect-vim-modules" 
(?), if any.


For now, I have preview of neither of eselect module variants, nor even 
patches for another "ways". I'd very like to discuss the situation and find a 
better of possible solution first.
Maybe, when (if?) we found such a solution, I'd contribute a PR with it on GH.

--
wbr,
mva