Computercraft Turtle Quarry Program

local args = {...}

if #args ~= 3 then
  print("Usage: quarry <row length> <number of rows> <current y>")
  error()
end

rowLength = args[1]
rows = args[2]
startingY = args[3]
curRow = 1

y = startingY

function full()
  fullSlots = 0
  for i=2,15 do
    if turtle.getItemCount(i) > 0 then
      fullSlots = fullSlots + 1
    end
  end
  print(fullSlots .. " slots are full")
  return(fullSlots == 14)
end

function checkFuel()
  if turtle.getFuelLevel() < 10 then
    turtle.select(1)
    turtle.refuel(1)
    end
end

function digMove()
  checkFuel()
  while turtle.detect() do
    turtle.dig()
    os.sleep(0.5)
  end
  turtle.forward()
  turtle.digUp()
  turtle.digDown()
end

function turn()
  if curRow % 2 == 0 then
    turtle.turnRight()
  else
    turtle.turnLeft()
  end
end

function dig()
  turtle.digDown()
  turtle.down()
  y = y - 1
end

function back()
  turtle.turnLeft()
  for i=1,rows do
    checkFuel()
    turtle.forward()
  end
  turtle.turnLeft()
end

function up()
  for i=1,(startingY - y) do
    checkFuel()
    turtle.up()
    y = y + 1
  end
end


function down(x)
  for i=1,x do
    checkFuel()
    dig(x)
  end
end

function chest()
  turtle.turnLeft()
  turtle.turnLeft()
  for i=2,16 do
    turtle.select(i)
    turtle.drop()
  end
  if turtle.getItemCount(1) < 3 then
    turtle.up()
    turtle.select(1)
    turtle.suck()
    turtle.down()
  end
  turtle.turnRight()
  turtle.turnRight()
end

function level()
  curRow = 1
  for i=1,rows do
    for i=1,rowLength-1 do
      digMove()
    end
    if curRow == tonumber(rows) then

    else
      turn()
      digMove()
      turn()
      curRow = curRow + 1
    end
  end
  back()
  tempY = y
  if full() then
    up()
    chest()
    down(startingY - tempY + 3)
  else
    down(3)
  end
  turtle.digDown()
end

function quarry()
  down(2)
  turtle.digDown()
  while y > 5 do
    level()
  end
  up()
end

quarry()