wallup

local tArgs = { ... }

if #tArgs == 0 then
        print( "Usage: wallup <length> [depth] " )
        return
end

local length = tonumber( tArgs[1] )
if length < 2 then
        print( "wall length must be > 2" )
        return
end

local depth = 256
if #tArgs >= 2 then
  depth = tonumber( tArgs[2] )
  if depth < 1 then
        print( "wall depth must be positive" )
        return
  end
end

local function digForward()
  while (turtle.detect()) do
    turtle.dig()
    sleep(0.2)
  end
end

local function digUp()
  while (turtle.detectUp()) do
    turtle.digUp()
    sleep(0.2)
  end
end


local relY = 0

local function tryDown()
  if (turtle.detectDown()) then
     turtle.digDown()
  end

  if (turtle.detectDown()) then
    return false
  end
  if (turtle.down()) then
    relY = relY-1
    return true
  else
    return false
  end
end


local function tryUp()
  while (turtle.detectUp()) do
     turtle.digUp()
  end
  if (turtle.up()) then
    relY = relY + 1
    return true
  else
    return false
  end
end

local function suckAll()
  while turtle.suck() do
  end
end

local function wallLayer()
  for side=1,4 do
    for i=1,(length) do
      turtle.turnLeft()
      suckAll()
      if not turtle.compare() then
        digForward()
        suckAll()
        turtle.place()
      end
      turtle.turnRight()
      if i< length then
        digForward()
        turtle.forward()
      end
    end
    turtle.turnRight()
  end
end

local function returnToTop()
  while relY < 0 do
    local canUp = tryUp()
    if not canUp then
      break
    end
  end
end

turtle.select(1)
for curDepth=1,depth do
  wallLayer()
  if curDepth < depth then
    local canDown = tryDown()
    if not canDown then
      break
    end
  end
end
returnToTop()