Computercraft (Mining Turtle) - stairs building Turtle

-- Program name : stairs building Turtle
-- description  : with this program you can with a turtle digging stairs
-- developer    : JohnnyNordx
-- updated on   : 20-03-2015

function up()
    turtle.up()
    for ux=2, lay do
        while turtle.detect() do
            turtle.dig()
        end
        sleep(0.5)
        if turtle.detect() then
            while turtle.detect() do
                turtle.dig()
                sleep(0.5)
            end
        end
        turtle.forward()
        turtle.digUp()
        turtle.digDown()
        turtle.up()
        turtle.digUp()
    end
end

function down()
    -- 0 lay
    turtle.digDown()
    -- 1 lay
    turtle.down()
    while turtle.detect() do
        turtle.dig()
    end
    sleep(0.5)
    if turtle.detect() then
        while turtle.detect() do
            turtle.dig()
            sleep(0.5)
        end
    end
    turtle.forward()
    turtle.digDown()
    -- 2 lay
    turtle.down()
    while turtle.detect() do
        turtle.dig()
    end
    sleep(0.5)
    if turtle.detect() then
        while turtle.detect() do
            turtle.dig()
            sleep(0.5)
        end
    end
    turtle.forward()
    turtle.digUp()
    turtle.digDown()
    while turtle.detect() do
        turtle.dig()
    end
    sleep(0.5)
    if turtle.detect() then
        while turtle.detect() do
            turtle.dig()
            sleep(0.5)
        end
    end
    -- 2-3 lay
    turtle.forward()
    turtle.digUp()
    while turtle.detect() do
        turtle.dig()
    end
    sleep(0.5)
    if turtle.detect() then
        while turtle.detect() do
            turtle.dig()
            sleep(0.5)
        end
    end
    turtle.digDown()
    -- 3 lay
    turtle.down()
    turtle.digDown()
    lay = lay-3

for dx=2,lay do
    while turtle.detect() do
        turtle.dig()
    end
    sleep(0.5)
    if turtle.detect() then
        while turtle.detect() do
            turtle.dig()
            sleep(0.5)
        end
    end
    turtle.forward()
    turtle.digUp()
    turtle.digDown()
    turtle.dig()
    turtle.down()
    turtle.digDown()
    end
end

function fuel()
    term.write("put fuel in slot 1 (if is more then 64 put it in next slot)")
    line()
    term.write("Press S to start")
    while true do
        local sEvent, param = os.pullEvent("key")
        if sEvent == "key" then
            if param == 31 then
                cl()
                print("Turtle Running")
                break
            end
        end
    end
    for slot=1,16 do
        turtle.select(slot)
        turtle.refuel()
    end
end

function cl()
term.clear()
lx = "0"
line()
end

function line()
lx = lx+1
term.setCursorPos(1,lx)
end

lx = "0"

-- terminal menu
cl()
term.write("Stairs Building Turtle")
line()
term.write("Up = from below and if selected,")
line()
term.write("     right up to the sky")
line()
term.write("Down = from top and if selected,")
line()
term.write("       right down to the bedrock")
line()
line()
term.write("Up/Down : ")
term.setCursorBlink(true)
ud = read()

if ud == "Up" or ud == "up" then
    line()
    term.write("how many layers ? : ")
    lay = read()
    fuel()
    up()
elseif ud == "Down" or ud == "down" then
    line()
    term.write("how many layers ? : ")
    lay = read()
    fuel()
    down()
else
    os.reboot()
end
cl()
write("completed")
line()