Road

dbug=true

local function roadLength(rs)
  if dbug then
    print("roadLength")
  end
  items=0
  for i=1,15 do
    print(i)
    print(rs)
    turtle.select(i)
    if turtle.compareTo(rs) then
        items=turtle.getItemCount(i)+items
    end
  end
  print(items)
  return items/2
end

local function moveForward()
  if dbug then
    print("moveForward")
  end
  while not turtle.forward() do
    turtle.attack()
  end
end

local function getItem()
  if dbug then
    print("getItem")
  end
  while currentSlot ~= referenceSlot do
    turtle.select(currentSlot)
    while turtle.compareTo(referenceSlot) do
        return true
    end
    currentSlot=currentSlot+1
  end
  quit=true
  return false
 end

local function dig()
  if dbug then
    print("dig")
  end
  turtle.dig()
  turtle.digUp()
  turtle.digDown()
  turtle.up()
  turtle.digUp()
  turtle.down()
end

local function clearArea()
  if dbug then
    print("clearArea")
  end
  dig()
  if getItem() then
    turtle.placeDown()
    turtle.turnLeft()
    turtle.dig()
    moveForward()
    turtle.turnRight()
    dig()
  end
  if getItem() then
    turtle.placeDown()
    turtle.turnRight()
    moveForward()
    turtle.turnLeft()
  end
end

--Start
xPos,zPos=0,0
xDir,zDir=0,1
height=0
referenceSlot=16
currentSlot=1
quit=false

zMax=roadLength(referenceSlot)

if dbug then
  print(xPos .. "," .. zPos)
  print(xDir .. "," .. zDir)
  print(height)
  print(zMax)
end

print("Starting...")
turtle.dig()
while zPos < zMax  and not quit do
  moveForward()
  zPos=zPos+1
  print("zPos: " .. zPos)
  clearArea()
end

print("zPos: " .. zPos)