selection

local termWidth, termHeight = term.getSize()
local selectedItem = 10
local onMainMenu = true

function Choice1()
 term.clear()

 print("CHOICE 1")
 sleep(1)
end

function Choice2()
term.clear()

print("CHOICE 2")
sleep(1)
end

function Choice3()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice4()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice5()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice6()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice7()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice8()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice9()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice10()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice11()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice12()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice13()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice14()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice15()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice16()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice17()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice18()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice19()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Choice20()
term.clear()

print("CHOICE 2")
sleep(1)
end
function Exit()
 onMainMenu = false
end

mainMenu = {
[1] = { text = "Choice 1", handler = Choice1 },
[2] = { text = "Choice 2", handler = Choice2 },
[3] = { text = "Exit", handler = Exit },
[4] = { text = "Choice 3", handler = Choice3 },
[5] = { text = "Choice 4", handler = Choice4 },
[6] = { text = "Choice 5", handler = Choice5 },
[7] = { text = "Choice 6", handler = Choice6 },
[8] = { text = "Choice 7", handler = Choice7 },
[9] = { text = "Choice 8", handler = Choice8 },
[10] = { text = "Choice 9", handler = Choice9 },
[11] = { text = "Choice 10", handler = Choice10 },
[12] = { text = "Choice 11", handler = Choice11 },
[13] = { text = "Choice 12", handler = Choice12 },
[14] = { text = "Choice 13", handler = Choice13 },
[15] = { text = "Choice 14", handler = Choice14 },
[16] = { text = "Choice 15", handler = Choice15 },
[17] = { text = "Choice 16", handler = Choice16 },
[18] = { text = "Choice 17", handler = Choice17 },
[19] = { text = "Choice 18", handler = Choice18 },
[20] = { text = "Choice 19", handler = Choice19 },
[21] = { text = "Choice 20", handler = Choice20 },
}

function printMenu( menu )
 for i=1,#menu do
  if i == selectedItem then
   term.clear()
   term.setCursorPos(1,1)
   print(">> "..menu[i].text.."  ")
  else
   print("   "..menu[i].text.."  ")
  end
 end
end

function onKeyPressed( key, menu )
 if key == 28 then
  onItemSelected(menu)
 elseif key == 200 then
  if selectedItem > 1 then
   selectedItem = selectedItem - 1
  end
 elseif key == 208 then
  if selectedItem < #menu then
   selectedItem = selectedItem + 1
  end
 end
end

function onItemSelected( menu )
 menu[selectedItem].handler()
end

function main()
 while onMainMenu do
  term.clear()
  term.setCursorPos(1,1)
  printMenu(mainMenu)
  event, key = os.pullEvent("key")
  onKeyPressed(key,mainMenu)
 end
end

main()