curses example drawing a menu

menu.rb

require "curses"
include Curses

init_screen
start_color
noecho

def draw_menu(menu, active_index=nil)
  4.times do |i|
    menu.setpos(i + 1, 1)
    menu.attrset(i == active_index ? A_STANDOUT : A_NORMAL)
    menu.addstr "item_#{i}"
  end
end

def draw_info(menu, text)
  menu.setpos(1, 10)
  menu.attrset(A_NORMAL)
  menu.addstr text
end

position = 0

menu = Window.new(7,40,7,2)
menu.box('|', '-')
draw_menu(menu, position)
while ch = menu.getch
  case ch
  when 'w'
    draw_info menu, 'move up'
    position -= 1
  when 's'
    draw_info menu, 'move down'
    position += 1
  when 'x'
    exit
  end
  position = 3 if position < 0
  position = 0 if position > 3
  draw_menu(menu, position)
end