Identifiers ​

Identifiers are how Red manages events. They turn any string to a short string identifier that can be used efficiently over the network.

Identifier Generation ​

Identifiers are generated by incrementally increasing a value, and then turning that value into a string using utf8.char. We choose this specific function, as it will increase the length of the string as the value increases. It starts at a length of 1. At 2^7 it creates a length of 2. At 2^11 it creates a length of 3, and so on.

Serdes.NextId = 0

function Serdes.RegisterIdentifier(Name: string)
	local Id = utf8.char(Serdes.NextId)
	Serdes.NextId += 1

	return Id
end

Identifier Replication ​

Whenever an identifier is created, all clients need to be able to use it, so they can parse events sent using it. This is done by using attributes placed directly on RedEvent. As these attributes must be placed on the server to replicate, identifiers can therefor only be registered on the server.

Serdes.NextId = 0

function Serdes.RegisterIdentifier(Name: string)
	assert(RunService:IsServer())

	local Id = utf8.char(Serdes.NextId)
	Serdes.NextId += 1

	Event:SetAttribute(Name, Id)

	return Id
end

One Time Identifiers ​

To facilitate returning values from function-like calls, Red uses one time identifiers. These are identifiers that are only used once, and then discarded. They are generated the same way as normal identifiers, except if the value reaches 0xFFFF + 1 it is reset back to 0.

Serdes.NextOT = 0

function Serdes.OneTime()
	Serdes.NextOT += 1

	if Serdes.NextOT == 0xFFFF + 1 then
		Serdes.NextOT = 0
	end

	return utf8.char(Serdes.NextOT)
end