Use vim-vsnip for LSP snippet completion.

tmux.conf

@@ -47,7 +47,7 @@ bind c new-window -c "#{pane_current_path}"
 #  mouse mode
 set -g mouse on
 
-bind -n C-F run "tmux new-window 'zsh -ci fs'"
+bind -n C-g run "tmux new-window 'zsh -ci fs'"
 
 # Plugins installed via TPM.
 # None currently.

vim/lua/lsp.lua

@@ -5,25 +5,39 @@ local onAttach = function(client)
   require'diagnostic'.on_attach(client)
 end
 
+-- Completion settings
+vim.o.completeopt='menuone,noinsert,noselect'
+vim.g.completion_enable_snippet = 'vim-vsnip'
+vim.g.completion_matching_strategy_list = {'exact', 'substring', 'fuzzy'}
+vim.g.completion_confirm_key = '<CR>'
+vim.g.completion_matching_ignore_case = true
+
+local capabilities = vim.lsp.protocol.make_client_capabilities()
+capabilities.textDocument.completion.completionItem.snippetSupport = true
+
 -- TS/JS
 nvimLsp.tsserver.setup{
-  on_attach = onAttach;
-  root_dir = nvimLsp.util.root_pattern(".git", "package.json")
+  on_attach = onAttach,
+  root_dir = nvimLsp.util.root_pattern(".git", "package.json"),
+  capabilities = capabilities
 }
 
 -- JSON
 nvimLsp.jsonls.setup{
-  on_attach = onAttach;
+  on_attach = onAttach,
+  capabilities = capabilities
 }
 
 -- Lua
 nvimLsp.sumneko_lua.setup{
-  on_attach = onAttach;
+  on_attach = onAttach,
+  capabilities = capabilities
 }
 
 -- Viml
 nvimLsp.vimls.setup{
-  on_attach = onAttach;
+  on_attach = onAttach,
+  capabilities = capabilities
 }
 
 -- Dart
@@ -38,6 +52,8 @@ nvimLsp.vimls.setup{
 --
 
 -- cpp
+-- Use vim-lsc for cpp until https://github.com/neovim/neovim/issues/12972 is resolved.
 nvimLsp.clangd.setup{
-  on_attach = onAttach;
+  on_attach = onAttach,
+  capabilities = capabilities
 }

vim/plugin/vim-vsnip.vim

@@ -0,0 +1,15 @@
+" NOTE: You can use other key to expand snippet.
+
+" Expand
+imap <expr> <C-j>   vsnip#expandable()  ? '<Plug>(vsnip-expand)'         : '<C-j>'
+smap <expr> <C-j>   vsnip#expandable()  ? '<Plug>(vsnip-expand)'         : '<C-j>'
+
+" Expand or jump
+imap <expr> <Tab>   vsnip#available(1)  ? '<Plug>(vsnip-expand-or-jump)' : '<Tab>'
+smap <expr> <Tab>   vsnip#available(1)  ? '<Plug>(vsnip-expand-or-jump)' : '<Tab>'
+
+" Jump forward or backward
+imap <expr> <C-f>   vsnip#jumpable(1)   ? '<Plug>(vsnip-jump-next)'      : '<C-f>'
+imap <expr> <C-b> vsnip#jumpable(-1)  ? '<Plug>(vsnip-jump-prev)'      : '<C-b>'
+smap <expr> <C-f>   vsnip#jumpable(1)   ? '<Plug>(vsnip-jump-next)'      : '<C-f>'
+smap <expr> <C-b> vsnip#jumpable(-1)  ? '<Plug>(vsnip-jump-prev)'      : '<C-b>'