[nvim] add a language server for Vimscript

nvim/coc-languages/c.vim

@@ -6,9 +6,7 @@ let g:coc_user_config['languageserver.ccls'] = {
 \ 'command': 'ccls',
 \ 'rootPatterns': ['.ccls', 'compile_commands.json', '.vim/', '.git/', '.hg/'],
 \ 'initializationOptions': {
-\   'cache': {
+\   'cache.directory': tempname(),
-\     'directory': '/tmp/ccls',
-\     },
 \   },
 \ }
 

nvim/coc-languages/vim.vim

@@ -0,0 +1,52 @@
+let s:filetypes = ['vim']
+let g:coc_filetypes += s:filetypes
+
+let g:coc_global_extensions += ['coc-vimlsp']
+let g:coc_user_config['vimlsp'] = {
+\ 'suggest.fromRuntimepath': v:true,
+\ }
+
+" The coc-vimlsp plugin is basically reimplemented here because it doesn't do
+" much beyond just wrapping the language server and passing some init options,
+" but having two processes (plugin+LSP) almost doubles the memory usage.
+"
+" On a second thought... Apparently that's just how this extension works...
+" Either way it spawns two processes (with the controller process having
+" roughly the same memory usage regardless of being in a coc extension). And
+" having updates through :CocUpdate is nice, so I'm gonna use the coc-vimlsp
+" plugin itself. The janky reimplementation is left in this file for better
+" times and bragging purposes.
+finish
+
+" <https://github.com/iamcco/coc-vimlsp/blob/38beb0033c24a50e306343282acb071ffae6eed4/src/index.ts#L47-L82>
+" workspace.isNvim: <https://github.com/neoclide/coc.nvim/blob/1c25102840e1d6d36bca9db8114e8a56f480afc4/autoload/coc/util.vim#L539>
+let g:coc_user_config['languageserver.vimls'] = {
+\ 'filetypes': s:filetypes,
+\ 'command': 'vim-language-server',
+\ 'args': ['--stdio'],
+\ 'initializationOptions': {
+\   'isNeovim': has('nvim'),
+\   'iskeyword': &iskeyword,
+\   'vimruntime': $VIMRUNTIME,
+\   'runtimepath': &runtimepath,
+\   'suggest.fromRuntimepath': v:true,
+\   },
+\ }
+
+augroup dotfiles-coc-vimls
+  autocmd!
+
+  " NOTE: Apparently delaying runtimepath initialization even until VimEnter
+  " is not enough, as coc-snippets adds its plugin to rtp during coc
+  " intialization phase which happens sometime after VimEnter[1]. Although,
+  " judging by the coc source code, custom language servers are initialized
+  " just before activation of extensions[2], and coc-snippets adds its plugin
+  " to rtp in the activation phase[3], so this might be reasonable for us.
+  " [1]: <https://github.com/neoclide/coc.nvim/blob/1c25102840e1d6d36bca9db8114e8a56f480afc4/src/attach.ts#L111-L115>
+  " [2]: <https://github.com/neoclide/coc.nvim/blob/1c25102840e1d6d36bca9db8114e8a56f480afc4/src/plugin.ts#L445-L446>
+  " [3]: <https://github.com/neoclide/coc-snippets/blob/053311a0d9edcc88b9dc0a8e8375dd82b7705f61/src/index.ts#L102>
+  autocmd VimEnter * let g:coc_user_config['languageserver.vimls.initializationOptions.runtimepath'] = &runtimepath
+
+  autocmd User CocNvimInit call CocNotify('vimls', '$/change/iskeyword', &iskeyword)
+  autocmd OptionSet iskeyword call CocNotify('vimls', '$/change/iskeyword', v:option_new)
+augroup END