Turtle

local moves = 0
tArgs = { ... }
function move( dig )
	if dig == true then
		turtle.dig()
		while not turtle.forward() do
			turtle.dig()
		end
	end
end

function upAndDown()
	turtle.digUp()
	turtle.digDown()
end

function row()
	move( true )
	upAndDown()
end

function checkForFuel()
	for i = 1, 16 do
		result = turtle.getItemDetail()
		if result then
			if result.name == "minecraft:coal" then
				turtle.select( i )
				if result.count / 4 == math.floor( result.count / 4 ) then
					turtle.refuel( result.count / 4)
				else
					turtle.refuel( math.floor( result.count / 4 ) )
				end
			end
		end
	end
end

function work( t )
	for i = 1, t[ 1 ] do
		if turtle.getFuelLevel() < 100 then
			checkForFuel()
		end
		row()
		turtle.turnLeft()
		row()
		while not turtle.back() do
			turtle.dig()
		end
		turtle.turnRight()
		turtle.turnRight()
		row()
		while not turtle.back() do
			turtle.dig()
		end
		turtle.turnLeft()
		moves = moves + 1
	end
end

if #tArgs ~= 1 then
	print( "Usage: " .. shell.getRunningProgram() .. " <length>" )
else
	work( tArgs )
	for i = 1, moves do
		turtle.back()
	end
end
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