added SuperTab-like functionality to autocompletion

nvim/.config/nvim/after/plugin/nvim-cmp.lua

@@ -1,4 +1,12 @@
--- Set up nvim-cmp.
+-- Set up nvim-cmp with luasnip 
+
+local has_words_before = function()
+  unpack = unpack or table.unpack
+  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
+  return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
+end
+
+local luasnip = require("luasnip")
 local cmp = require'cmp'
 
 cmp.setup({
@@ -22,6 +30,29 @@ cmp.setup({
         ['<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.
+        ["<Tab>"] = cmp.mapping(function(fallback)
+            if cmp.visible() then
+                cmp.select_next_item()
+                -- You could replace the expand_or_jumpable() calls with expand_or_locally_jumpable() 
+                -- they way you will only jump inside the snippet region
+            elseif luasnip.expand_or_jumpable() then
+                luasnip.expand_or_jump()
+            elseif has_words_before() then
+                cmp.complete()
+            else
+                fallback()
+            end
+        end, { "i", "s" }),
+
+        ["<S-Tab>"] = cmp.mapping(function(fallback)
+            if cmp.visible() then
+                cmp.select_prev_item()
+            elseif luasnip.jumpable(-1) then
+                luasnip.jump(-1)
+            else
+                fallback()
+            end
+        end, { "i", "s" }),
     }),
     sources = cmp.config.sources({
         { name = 'nvim_lsp' },