Copying the Reselect API in ~40 lines of code. Does not allocate on call. Untested.

selector-example.lua

local function applySelector(selector, ...)
	if typeof(selector) == "string" then
		return (...)[selector]
	else
		return selector(...)
	end
end

local function listShallowEqual(a, b, len)
	for i = 1, len do
		if a[i] ~= b[i] then
			return false
		end
	end

	return true
end

local function createSelector(inputSelectors, fn)
	local lastValues = {}
	local values = {}
	local result = nil
	local numInputSelectors = #inputSelectors

	return function(...)
		for i = 1, numInputSelectors do
			values[i] = applySelector(inputSelectors[i], ...)
		end

		if listShallowEqual(values, lastValues, numInputSelectors) then
			return result
		end

		result = fn(unpack(values))

		values, lastValues = lastValues, values

		return result
	end
end