ComputerCraft - Clear Space

function turnAround()
    turtle.turnLeft()
    turtle.turnLeft()
end

function sandDig()
    while turtle.detect() do
        turtle.dig()
    end
end

function forward(n) -- Forwad and dig
    for i=1,n do
        sandDig()
        turtle.forward()
    end
end

function down(n) -- Down n times
    for i = 1,n do
        turtle.down()
    end
end

function digL() -- Dig length
    if l > 0 then
        for i = 1,l-1 do
            sandDig()
            turtle.forward()
        end
    end
end

function nextRow()
    if count % 2 == 0 then -- Right for even number rows
        turtle.turnRight()
        sandDig()
        turtle.forward()
        turtle.turnRight()
    else -- Left for odd number rows
        turtle.turnLeft()
        sandDig()
        turtle.forward()
        turtle.turnLeft()
    end
    count = count + 1
end

function section()
    for i = 1,w do
        digL() -- Dig out length and move to next rows
        if i < w then -- Won't start extra row at end
            nextRow() -- Digs one whole section
        end
    end
end

function nextSection()
    turtle.digUp() -- Moves to next section (up)
    turtle.up()
    turnAround()
end

function goingUp() -- Digs base section, moves up
    for i = 1,h do -- Drives whole program
        if w % 2 == 0 then -- Even number widths need alternating nextRow
            if i % 2 == 0 then -- ^ orientations.
                count = 0
            else
                count = 1
            end
        else
            count = 1
        end
        section()
        if i < h then -- Won't go up extra block at end
            nextSection()
        end
    end
end

function goingDown() -- Go to lowest level first
    for i = 1,d do
        turtle.digDown()
        turtle.down()
    end
end

count = 1 -- For nextRow function

print("How far forward? (length)")
l = tonumber(read()) -- Length
print("How far left? (width)")
w = tonumber(read()) -- Width
print("How tall? (at least 1)")
h = tonumber(read()) -- Height
print("How deep? (0 for this level)")
d = tonumber(read()) -- Depth

if d > 0 then
    print("Going down!")
    goingDown()
end
if h > 0 then
    print("Here I go!")
    goingUp()
end
if h > 0 then
    print("Complete.")
    down(h) -- Parks turtle in bottom corner
end