Computercraft ClearArea Progam

function drop()

    for slot=1,9 do
        turtle.select(slot)
        turtle.drop()
    end

end

function ClearUp()

    count=0

    while turtle.detectUp() do
        turtle.digUp()
        turtle.up()
        count = count+1
    end

    for k=1,count do
        turtle.down()
    end

end

function ClearLine(depth)

    for i=1,depth do
        turtle.dig()
        turtle.forward()
        ClearUp()
    end
end

function ClearArea()

    for j=1,length/2 do
        ClearLine(depth)
        turtle.turnRight()
        turtle.dig()
        turtle.forward()
        ClearUp()
        turtle.turnRight()
        ClearLine(depth)
        turtle.turnLeft()
        turtle.dig()
        turtle.forward()
        ClearUp()
        turtle.turnLeft()
        drop()
    end
end

function Return()

    turtle.turnLeft()

    for l=1,length do
        turtle.forward()
    end

    turtle.turnRight()

end

print("How deep should I clear?")
depth = read()
print("How wide (right of here) should I clear?")
length = read()
slot = 1
turtle.select(1)

ClearArea()
Return()
turtle.select(1)