Set up Neovim native LSP for completion

neovim/init.lua

@@ -1,3 +1,4 @@
 require("basics")
 require("keymaps")
 require("plugins")
+require('lsp')

neovim/lua/lsp.lua

@@ -0,0 +1,5 @@
+vim.lsp.config('*', {
+  capabilities = require('cmp_nvim_lsp').default_capabilities(),
+})
+
+vim.lsp.enable("gopls")

neovim/lua/plugins.lua

@@ -9,6 +9,16 @@ vim.call('plug#begin')
 
 Plug("Shougo/vimproc.vim", { ["do"] = "make" })
 
+-- LSP & completion
+Plug("neovim/nvim-lspconfig")
+Plug 'hrsh7th/cmp-nvim-lsp'
+Plug 'hrsh7th/cmp-buffer'
+Plug 'hrsh7th/cmp-path'
+Plug 'hrsh7th/cmp-cmdline'
+Plug 'hrsh7th/nvim-cmp'
+Plug 'hrsh7th/cmp-vsnip'
+Plug 'hrsh7th/vim-vsnip'
+
 -- filer
 Plug("vifm/vifm.vim")
 Plug("scrooloose/nerdtree")
@@ -51,6 +61,55 @@ Plug("tyru/open-browser-github.vim")
 
 vim.call("plug#end")
 
+-- configs of nvim-cmp {{{
+local cmp = require'cmp'
+
+cmp.setup({
+  snippet = {
+    -- REQUIRED - you must specify a snippet engine
+    expand = function(args)
+      vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
+    end,
+  },
+  window = {
+    completion = cmp.config.window.bordered(),
+    documentation = cmp.config.window.bordered(),
+  },
+  mapping = cmp.mapping.preset.insert({
+    ['<C-b>'] = cmp.mapping.scroll_docs(-4),
+    ['<C-f>'] = cmp.mapping.scroll_docs(4),
+    ['<C-Space>'] = cmp.mapping.complete(),
+    -- ['<C-e>'] = cmp.mapping.abort(),
+    ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
+  }),
+  sources = cmp.config.sources({
+    { name = 'nvim_lsp' },
+    { name = 'vsnip' }, -- For vsnip users.
+  }, {
+    { name = 'buffer' },
+  })
+})
+
+-- Use buffer source for `/` and `?` (if you enabled `native_menu`, this won't work anymore).
+cmp.setup.cmdline({ '/', '?' }, {
+  mapping = cmp.mapping.preset.cmdline(),
+  sources = {
+    { name = 'buffer' }
+  }
+})
+
+-- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
+cmp.setup.cmdline(':', {
+  mapping = cmp.mapping.preset.cmdline(),
+  sources = cmp.config.sources({
+    { name = 'path' }
+  }, {
+    { name = 'cmdline' }
+  }),
+  matching = { disallow_symbol_nonprefix_matching = false }
+})
+-- }}}
+
 -- configs of nerdtree {{{
 map({ "n", "v", "o" }, "<C-e>", "<cmd>NERDTreeToggle<CR>", { noremap = true })
 map({ "n", "v", "o" }, "<C-t>", "<cmd>NERDTreeFind<CR>",   { noremap = true })