print("Mining stairs. Press any key to abort.")

getKey = function()
	local key = os.pullEvent("char")
	if key ~= nil then
		print("Aborted due to user keypress")
		return
	end
end

mineStairs = function()
	while true do
		if turtle.digDown() then
			turtle.dig()
			turtle.down()
			turtle.dig()
			turtle.forward()
		else
			break
		end
	end
	print("Cannot dig down; waiting for humans.")
end

parallel.waitForAny(mineStairs, getKey)
