Dig Tunnel

--Dig Tunnel

function digIt()
    while turtle.detect() do
      turtle.dig()
      os.sleep(0.5)
    end
    turtle.forward()
    while turtle.detectDown() or turtle.detectUp() do
      turtle.digUp()
      turtle.digDown()
    end
  end

  function placeTorch()
    turtle.select(16)
    turtle.placeFront()
  end

  local run = 0
  term.write("Tunnel length: ")
  run = read()

  for x = 1, run do
    y = x - 1
    z = y % 4
    digIt()
    turtle.turnLeft()
    digIt()
    turtle.turnRight()
    turtle.turnRight()
    turtle.forward()
    digIt()
    turtle.back()
    turtle.turnLeft()

    if x == 2 or z == 1 then
      turtle.back()
      turtle.turnRight()
      turtle.forward()
      placeTorch()
      turtle.back()
      turtle.back()
      turtle.turnRight()
      turtle.turnRight()
      placeTorch()
      turtle.turnRight()
      turtle.turnRight()
      turtle.forward()
      turtle.turnLeft()
      turtle.forward()
    end
   -- Place final torch mid wall
   turtle.down()
   turtle.turnRight()
   turtle.turnRight()
   turtle.select(16)
   turtle.placeUp()

   --Return to start
   for x = 1, run do
     turtle.forward()
   end