Mining tunnel

local args = {...}
length = args[1]

function dig()
        while turtle.detect() do
            turtle.dig()
            os.sleep(0.5)
        end
end
function digUp()
        while turtle.detectUp() do
            turtle.digUp()
            os.sleep(0.5)
        end
end
function forward()
    while turtle.forward()==false do
        os.sleep(1)
        dig()
    end
end

function row()
    digUp()
    turtle.digDown()
    for m=1,4,1 do
        dig()
        forward()
        digUp()
        turtle.digDown()
    end
end

----------------------------
for i=1,length,1 do
    dig()
    forward()
    turtle.turnRight()
    row()
    turtle.down()
    turtle.digDown()
    turtle.turnRight()
    turtle.turnRight()
    for u=1,4,1 do
        forward()
        turtle.digDown()
    end
    turtle.up()
    turtle.turnRight()
end