pillars

args = {...}
nArgs = #args

version = "pillar: Rev 0.1"


materialSlot = 1
spacing = 8

function placePillar()
	local y = 0

	while turtle.down() do
		y = y-1
		if y < -20 then
			break
		end
	end

	turtle.select(1)
	while y < 0 do
		turtle.up()
		if ensureMaterial() then
			turtle.placeDown()
		end
		y = y+1
	end
end

function forward(nBlocks)
	local i = 0
	for i=1,nBlocks do
		turtle.forward()
	end
end

function ensureMaterial()
	if turtle.getItemCount(materialSlot) < 3 then
		organizeMaterial()
	end
	if turtle.getItemCount(materialSlot) < 3 then
		print("No more material")
		return false
	end
	return true
end

function organizeMaterial()
	local i
	materialCount = turtle.getItemCount(materialSlot)

	if materialCount < 3 then
		for i=2,16 do
			turtle.select(i)
			if turtle.compareTo(materialSlot) then
				turtle.transferTo(materialSlot)
			end
		end
	end
	turtle.select(materialSlot)
end

-- =================  Main Program  ===================

if nArgs == 0 or (nArgs == 1 and args[1]== "help") then
	print(version)
	print("Fill all slots with building material.")
	return
end

--[[
if nArgs < 2 or nArgs > 3 then
  print(usage)
  return
end
--]]

nPillars = tonumber(args[1])
if nPillars == nil then
  print("\"", args[1], "\" is not a valid number.")
  return
end
if nPillars < 1 then
  print("Number of pillars must be a positive integer.")
end

for i=1,nPillars do
	placePillar()
	if i < nPillars then
		forward(spacing)
	end
end