Help me please with my Programm

update = false
shouldRender = true
running = true
function clear()
  term.clear()
  term.setCursorPos(1,1)
end
function render()
  while running do
	if shouldRender then
	  clear()
	  print("+------------------+")
	  print("| PJOG Section Lua |")
	  print("| Redstone Furnace |")
	  print("+------------------+--------+")
	  print("| Druecke <g> um zu starten |")
	  print("| Druecke <s> um zu stoppen |")
	  print("+---------------+-----------+")
	  print("| Im Moment <"..(update and "R" or "S").."> |")
	  print("+---------------+")
	  shouldRender = false
	end
  end
end
function tick()
  while running do
  if update then
	rs.setOutput("bottom", true)
	sleep(1)
	rs.setOutput("bottom", false)
  end
  sleep(0)
  end
end
function waitFor()
  while running do
	e = {os.pullEvent()} --coroutine.yield
	if e[1] == "char" then
	  if e[2] == "g" then
		update = true
		shouldRender = true
	  elseif e[2] == "s" then
		update = false
		shouldRender = true
	  elseif e[2] == "q" then
		running = false
	  end
	end
  end
end
function time()
  while running do
  str = os.day.." "..textutils.formatTime(os.time(), true)
  w,h = term.getSize()
  term.setCursorPos(w-str:len(),h-1)
  term.write(str)
  end
end
local renderThread = coroutine.create(render)
local updateThread = coroutine.create(waitFor)
local actionThread = coroutine.create(tick)
local timer = coroutine.create(time)
function main()
  while running do
	e = {os.pullEvent()}
	resume = coroutine.resume(updateThread, unpack(e))
	coroutine.resume(renderThread)
	coroutine.resume(actionThread)
	coroutine.resume(timer)
  end
end
main()