config: nvim: rewrite config in lua and use packer as plugin manager

config/nvim/lua/utils.lua

@@ -0,0 +1,30 @@
+local M = {}
+
+-- keybinding mapper
+function M.map(mode, lhs, rhs, opts)
+	local options = { noremap = true, silent = true }
+	if opts then
+		options = vim.tbl_extend('force', options, opts)
+	end
+	vim.api.nvim_set_keymap(mode, lhs, rhs, options)
+end
+
+-- simple prompt
+function M.prompt(msg, accept_msg, deny_msg)
+	local answer = vim.fn.input(msg .. ' (YES/no) ')
+	while(true) do
+		-- clear vim cmdline before printing anything
+		vim.cmd('mode')
+		if answer == 'YES' then
+			print(accept_msg)
+			return true
+		elseif string.lower(answer) == 'no' then
+			print(deny_msg)
+			return false
+		end
+		-- re-request user input
+		answer = vim.fn.input('Please retry: ' .. msg .. ' (YES/no) ')
+	end
+end
+
+return M