ComputerCraft 1.5 Quarry Digger

local bedrockFound = false

local function goUp()
    local upFound = false

    while not upFound do
        if not turtle.moveUp() then
            upFound = true
        end
    end
end

local function checkInventorySpace()
    local isEmptySlot = false
    for i = 1, 16 do
        if turtle.getItemCount(i) <= 0 then
            isEmptySlot = true
            --break() TurtleOS 1.5 doesnt have?
        end
    end
    return isEmptySlot
end

local function emptyInventory()
    for i = 2, 16 do --empty every slot except first one (for fuel)
        turtle.select(i)
        turtle.dropUp()
    end
    turtle.select(1)
end

while not bedrockFound do
    turtle.select(1) --select slot 1 for fuel
    if turtle.getFuelLevel() <= 5 then
        turtle.refuel()
    end

    if checkInventorySpace() then --if has space in inventory do dig

        if turtle.detectDown() then
            local brokeBlock = turtle.digDown()

            if not brokeBlock then --block is unbreakable
                bedrockFound = true
            end
            turtle.moveDown()
        end
    else
        goUp()
        emptyInventory()
    end
end

if bedrockFound then
    goUp()
end