local Util = {}

function Util.indexOf(haystack, needle)
	for b,blade in pairs(haystack) do
		if blade == needle then return b end
	end
end

function Util.getNext(stack, item, d)
	local w = Util.indexOf(stack, item)
	if not w then return nil end
	local i = (((w-1) + d) % #stack) + 1
	return stack[i]
end

return Util