Construir linea recta

-- programa que construye un muro en linea recta hasta que choca con algo

turtle.select(1)

while turtle.forward() do
    while (turtle.getItemCount() == 0) and (turtle.getSelectedSlot() < 16) do
        turtle.select(turtle.getSelectedSlot() + 1)
    end

    if (turtle.getItemCount() == 0) and (turtle.getSelectedSlot() == 16) then
        return
    end

    turtle.digDown()
    turtle.placeDown()
end