Clean up config a little

init.lua

@@ -1,37 +1,4 @@
 vim.cmd("runtime vimrc")
 
-if (vim.fn.has 'win32' == 1) then
-    require'lspconfig'.powershell_es.setup{
-        bundle_path = os.getenv("LOCALAPPDATA") .. '\\PowerShellEditorServices',
-        shell = 'powershell.exe',
-    }
-else
-    require'lspconfig'.powershell_es.setup{
-        bundle_path = os.getenv("HOME") .. '/opt/PowerShellEditorServices',
-    }
-end
-
-require'lspconfig'.gopls.setup{}
-
--- None of this should be needed from 0.11.0 (except maybe gd).
-do
-    vim.keymap.set('n', 'gd', function()
-        vim.lsp.buf.definition()
-    end, { desc = 'vim.lsp.buf.definition()' })
-
-    vim.keymap.set('n', 'grn', function()
-        vim.lsp.buf.rename()
-    end, { desc = 'vim.lsp.buf.rename()' })
-
-    vim.keymap.set({ 'n', 'x' }, 'gra', function()
-        vim.lsp.buf.code_action()
-    end, { desc = 'vim.lsp.buf.code_action()' })
-
-    vim.keymap.set('n', 'grr', function()
-        vim.lsp.buf.references()
-    end, { desc = 'vim.lsp.buf.references()' })
-
-    vim.keymap.set('i', '<C-S>', function()
-        vim.lsp.buf.signature_help()
-    end, { desc = 'vim.lsp.buf.signature_help()' })
-end
+require('ant_tabcomplete')
+require('ant_lsp')

lua/ant_lsp.lua

@@ -0,0 +1,35 @@
+if (vim.fn.has 'win32' == 1) then
+    require'lspconfig'.powershell_es.setup{
+        bundle_path = os.getenv("LOCALAPPDATA") .. '\\PowerShellEditorServices',
+        shell = 'powershell.exe',
+    }
+else
+    require'lspconfig'.powershell_es.setup{
+        bundle_path = os.getenv("HOME") .. '/opt/PowerShellEditorServices',
+    }
+end
+
+require'lspconfig'.gopls.setup{}
+
+-- None of this should be needed from 0.11.0 (except maybe gd).
+do
+    vim.keymap.set('n', 'gd', function()
+        vim.lsp.buf.definition()
+    end, { desc = 'vim.lsp.buf.definition()' })
+
+    vim.keymap.set('n', 'grn', function()
+        vim.lsp.buf.rename()
+    end, { desc = 'vim.lsp.buf.rename()' })
+
+    vim.keymap.set({ 'n', 'x' }, 'gra', function()
+        vim.lsp.buf.code_action()
+    end, { desc = 'vim.lsp.buf.code_action()' })
+
+    vim.keymap.set('n', 'grr', function()
+        vim.lsp.buf.references()
+    end, { desc = 'vim.lsp.buf.references()' })
+
+    vim.keymap.set('i', '<C-S>', function()
+        vim.lsp.buf.signature_help()
+    end, { desc = 'vim.lsp.buf.signature_help()' })
+end

lua/ant_tabcomplete.lua

@@ -0,0 +1,40 @@
+vim.opt.completeopt = {'menu', 'menuone', 'noselect', 'noinsert'}
+vim.opt.shortmess:append('c')
+
+local function tab_complete()
+    if vim.fn.pumvisible() == 1 then
+        -- navigate to next item in completion menu
+        return '<Down>'
+    end
+
+    local c = vim.fn.col('.') - 1
+    local is_whitespace = c == 0 or vim.fn.getline('.'):sub(c, c):match('%s')
+
+    if is_whitespace then
+        -- insert tab
+        return '<Tab>'
+    end
+
+    local lsp_completion = vim.bo.omnifunc == 'v:lua.vim.lsp.omnifunc'
+
+    if lsp_completion then
+        -- trigger lsp code completion
+        return '<C-x><C-o>'
+    end
+
+    -- suggest words in current buffer
+    return '<C-x><C-n>'
+end
+
+local function tab_prev()
+    if vim.fn.pumvisible() == 1 then
+        -- navigate to previous item in completion menu
+        return '<Up>'
+    end
+
+    -- insert tab
+    return '<Tab>'
+end
+
+vim.keymap.set('i', '<Tab>', tab_complete, {expr = true})
+vim.keymap.set('i', '<S-Tab>', tab_prev, {expr = true})