Create a branch mine using a ComputerCraft Mining Turtle

branch.lua

--[[
    By: skylarsch
    Usage: branch <number of tunnels (8)> <length of each tunnel (10)> <space between tunnels (2)>

    Each of the arguments are optional, but if you must specify all the values before the one you want to change.
--]]

-- MARK: Helper Functions
function fwd() -- Move forward
  while not turtle.forward() do
    turtle.dig()
  end
end
function move(ammount) -- Move forward by the number of blocks
  for i = 0, ammount, 1 do
    fwd()
  end
end
function digUp() -- Dig up
  while turtle.detectUp() do
    turtle.digUp()
  end
end
function refuel() -- Refuel the turtle if it needs it
  local slot = 1
  while turtle.getFuelLevel() < 50 do
    if slot > 16 then
      print("Failed to refuel turtle")
      turtle.select(1)
      return false
    end
    turtle.select(slot)
    if not turtle.refuel(1) then
      slot = slot + 1
    end
  end
  turtle.select(1)
  return true
end
function makeTunnel(length)
  for i = 0, length, 1 do
    digUp()
    fwd()
  end
  digUp()
end
function aboutFace()
  turtle.turnRight()
  turtle.turnRight()
end

-- MARK: Main App Start
local argv = {...}
local brCount  = (argv[1] or 8) - 1
local brLength = (argv[2] or 10) - 1
local brSpace  = argv[3] or 2

print("Creating Branch Mine")

if not refuel() then
  print("Aborting...")
  return
end

for tunnel = 0, brCount, 1 do
  makeTunnel(brLength)

  aboutFace()
  move(brLength)

  if tunnel == brCount then
    break
  end

  turtle.turnLeft()

  move(brSpace)

  turtle.turnLeft()

  if not refuel() then
    print("Aborting...")
    return
  end
end

local back = brCount * (brSpace + 1) - 1
turtle.turnRight()
move(back)
turtle.turnRight()

refuel()