can anyone look at this?

xCoord = -164
zCoord = 195
yCoord = 72
xQuarry = 999
zQuarry = 999
yQuarry = 150
xProgress = 999
zProgress = 999
yProgress = 150
oProgress = 1
xHome = xCoord
zHome = zCoord
yHome = yCoord
yTravel = 85
orientation = 4
orientations = {"north", "east", "south", "west"}
zDiff = {-1, 0, 1, 0}
xDiff = {0, 1, 0, -1}
lineLength = 2
lines = 3
yMin = 999
function inventoryFull()
  turtle.select(9)
  full = turtle.getItemCount(9) > 0
  turtle.select(1)
  return full
end
function left()
  orientation = orientation - 1
  orientation = (orientation - 1) % 4
  orientation = orientation + 1
  turtle.turnLeft()
end
function right()
  orientation = orientation - 1
  orientation = (orientation + 1) % 4
  orientation = orientation + 1
  turtle.turnRight()
end
function moveForward()
  xCoord = xCoord + xDiff[orientation]
  zCoord = zCoord + zDiff[orientation]
  turtle.dig()

  moved = false
  while not(moved) do

	moved = turtle.forward()
  end
end
function moveUp()
  yCoord = yCoord + 1

  turtle.digUp()
  moved = false
  while not(moved) do

	moved = turtle.up()
  end
end
function moveDown()
  yCoord = yCoord - 1
  turtle.digDown()

  moved = false
  while not(moved) do

	moved = turtle.down()
  end

  if yMin > yCoord then

	yMin = yCoord
  end
end
function look(direction)
  while direction ~= orientations[orientation] do

	right()
  end
end
function goto(xTarget, zTarget, yTarget)
  while yTarget < yCoord do

	moveDown()
  end

  while yTarget > yCoord do

	moveUp()
  end

  if xTarget < xCoord then

	look("west")

	while xTarget < xCoord do
  
	  moveForward()

	end
  end
  if xTarget > xCoord then

	look("east")

	while xTarget > xCoord do
  
	  moveForward()

	end
  end

  if zTarget < zCoord then

	look("north")

	while zTarget < zCoord do
  
	  moveForward()

	end
  end
  if zTarget > zCoord then

	look("south")

	while zTarget > zCoord do
  
	  moveForward()

	end
  end
end
function returnItems()
  xProgress = xCoord
  zProgress = zCoord
  yProgress = yCoord
  oProgress = orientation

  goto(xHome, zHome, yTravel)
  goto(xHome, zHome, yHome)

  for i = 1,9 do

	turtle.select(i)

	turtle.drop()
  end
  turtle.select(1)

  goto(xProgress, zProgress, yTravel)
  goto(xProgress, zProgress, yProgress)
  look(orientations[oProgress])
end
function digLine()
  for i = 1,lineLength do

	if inventoryFull() then
  
	  returnItems()

	end

	moveForward()
  end
end
function digLayer()
  for i = 1,lines do

	digLine()

	if (i%2) == 1 and i < lines then
  
	  left()
  
	  moveForward()
  
	  left()

	elseif i < lines then
  
	  right()
  
	  moveForward()
  
	  right()

	end
  end
  goto(xQuarry, zQuarry, yCoord)
  look("north")
  moveDown()
end
function digQuarry(xTarget, zTarget, yTarget)
  xQuarry = xTarget
  zQuarry = zTarget
  yQuarry = yTarget

  goto(xQuarry, zQuarry, yTravel)
  goto(xQuarry, zQuarry, yQuarry)
  look("north")
  while yMin > 7 do

	digLayer()
  end
  goto(xQuarry, zQuarry, yQuarry)
  yMin = 999
end
digQuarry(-170, 210, 70)