Add config for vim-lsp

dev/vim-lsp.nix

@@ -0,0 +1,45 @@
+{ pkgs ? import <nixpkgs> { } }:
+pkgs.vim_configurable.customize {
+  name = "vim-lsp";
+
+  vimrcConfig = {
+    packages.myVimPackage.start = with pkgs.vimPlugins; [
+      vim-nix # File type and syntax highlighting.
+      vim-lsp
+    ];
+
+    # vim
+    customRC = ''
+      source ${./vimrc.vim}
+
+      au BufRead,BufNewFile *.nix setf nix
+
+      autocmd User lsp_setup call lsp#register_server({
+        \ 'name': 'nil',
+        \ 'cmd': {server_info->[$NIL_PATH]},
+        \ 'whitelist': ['nix'],
+        \ })
+      autocmd User lsp_buffer_enabled call s:on_lsp_buffer_enabled()
+
+      function! s:on_lsp_buffer_enabled()
+        setlocal omnifunc=lsp#complete
+        setlocal tagfunc=lsp#tagfunc
+
+        nmap <buffer> gd <Plug>(lsp-definition)
+        nmap <buffer> gr <Plug>(lsp-references)
+        nmap <buffer> gs <Plug>(lsp-document-symbol-search)
+        nmap <buffer> gS <Plug>(lsp-workspace-symbol-search)
+        nmap <buffer> gy <Plug>(lsp-type-definition)
+        nmap <buffer> <Space>r <Plug>(lsp-rename)
+        nmap <buffer> [g <Plug>(lsp-previous-diagnostic)
+        nmap <buffer> ]g <Plug>(lsp-next-diagnostic)
+        nmap <buffer> <Space><Space> <Plug>(lsp-hover)
+        nnoremap <buffer> <expr><C-f> lsp#scroll(+4)
+        nnoremap <buffer> <expr><C-d> lsp#scroll(-4)
+
+        let g:lsp_format_sync_timeout = 1000
+        autocmd BufWritePre *.nix call execute('LspDocumentFormatSync')
+      endfunction
+    '';
+  };
+}