Add simple tunnel script

tunnel.lua

@@ -0,0 +1,69 @@
+local function dig(up)
+  while up and turtle.inspectUp() do
+    turtle.digUp()
+  end
+
+  while turtle.inspect() do
+    turtle.dig()
+  end
+end
+
+local function forward()
+  while not turtle.forward() do
+    dig(false)
+  end
+end
+
+local function line(length)
+  for _=2,length do
+    forward()
+  end
+end
+
+local function fuelCheck(lineWidth)
+  return turtle.getFuelLevel() >= (lineWidth * 4)
+end
+
+local function awaitRefuel(lineWidth)
+  repeat
+    for i=1,16 do
+      if turtle.getItemCount(i) > 0 then
+        turtle.select(i)
+        turtle.refuel()
+      end
+    end
+  until fuelCheck(lineWidth)
+end
+
+
+local args = {...}
+local width = #args > 0 and tonumber(args[1])
+local startLeft = #args > 1 and #args[2] > 0 and string.lower(args[2]):sub(1,1) == 'l'
+
+local turn, otherTurn = turtle.turnLeft, turtle.turnRight
+if not startLeft then
+    turn, otherTurn = otherTurn, turn
+end
+
+-- Width 1 means we're just digging a line
+if width == 1 then
+  turn = function() end
+  otherTurn = function() end
+end
+
+if width < 1 then
+  error("Width must be at least 1")
+end
+
+while true do
+  if not fuelCheck(width) then
+    print("I need more fuel")
+    awaitRefuel()
+  end
+  forward()
+  turn()
+  line(width)
+  otherTurn()
+  
+  turn, otherTurn = otherTurn, turn
+end