test3.lua

local n = require('newt')

n.Init()
n.Cls()

menu = {
	"Item 1",
	"Item 2",
	"Item 3",
	"Item 4",
	"Item 5",
	"Item 6",
	"Item 7",
	"Item 8",
	"Item 9",
	"Item 10",
	"Item 11",
	"Item 12",
}

local menuitem = {}
local width = 0
local hotkey = {}

for i, v in ipairs(menu) do
	if i < 10 then 
		v = string.format("[F%d] %s", i, v)
		table.insert(hotkey, n.KEY_F1 + i - 1)
	end
	if width < #v then width = #v end
	menuitem[i] = v
end	

--[[
for i, v in ipairs(menuitem) do
	menuitem[i] = string.format("%" .. width .. "s", v)
end
]]

local msg = "Newt Test 3"
local cols, rows = n.GetScreenSize()
local height = #menuitem 
if #menuitem > (rows - 12) then height = rows - 12 end

n.DrawRootText((cols - #msg) / 2, rows / 2, msg)

n.PushHelpLine(nil)

n.CenteredWindow(width + 4, height + 2, "Menu")
form = n.Form()

flags = n.FLAG_RETURNEXIT
if height < #menuitem then flags = flags + n.FLAG_SCROLL end

list = n.Listbox(1, 1, height, flags)
list:AppendEntry(menuitem)

form:AddComponents(list)
form:AddHotKey(hotkey)

r, v = form:Run()
if r == n.EXIT_COMPONENT and v and v:ID() == list:ID() then
	sel = list:GetCurrent()
elseif r == n.EXIT_HOTKEY then
	sel = v - n.KEY_F1 + 1
end

n.Finished()

print(menu[sel])