Hilbert Turtle Miner

-- https://en.wikipedia.org/wiki/Hilbert_curve
-- The Hilbert Curve can be expressed by a rewrite system (L-system).
--     Alphabet : A, B
--     Constants : F + -
--     Axiom : A
--     Production rules:
--     A → - B F + A F A + F B -
--     B → + A F - B F B - F A +
-- Here, F means "draw forward", - means "turn left 90°", + means "turn right 90°" (see turtle graphics), and "A" and "B" are ignored during drawing.

currentSlot = 1
torchInterval = 13      -- Must correspond to lineLength
lineLength = 4
recursiveDepth = 4
repetition = 1
distance = 0

function A(depth)

   if depth < 1 then return end
   print("A" .. depth)
   turtle.turnLeft()
   B(depth - 1)
   F()
   turtle.turnRight()
   A(depth - 1)
   F()
   A(depth - 1)
   turtle.turnRight()
   F()
   B(depth - 1)
   turtle.turnLeft()

end

function B(depth)

   if depth < 1 then return end
   print("B" .. depth)
   turtle.turnRight()
   A(depth - 1)
   F()
   turtle.turnLeft()
   B(depth - 1)
   F()
   B(depth - 1)
   turtle.turnLeft()
   F()
   A(depth - 1)
   turtle.turnRight()

end

function F()

   for i = 1, lineLength do
      turtle.dig()
      turtle.forward()
      turtle.digDown()
      distance = distance + 1

      if distance % torchInterval == 0 then
         if turtle.getItemCount(currentSlot) > 1 then
            turtle.placeDown()
         else
            currentSlot = currentSlot + 1
            turtle.select(currentSlot)
            if currentSlot <= 16 and turtle.getItemCount(currentSlot) > 1 then
                  turtle.placeDown()
            end
         end
      end
   end
end

-- MAIN

-- Fuel completely before starting
-- Torches in all slots
-- Does not gather resources!
turtle.select(1)

for i=1, repetition do
   print("Repetition " .. repetition)
   A(recursiveDepth)
end