Structs

Structs are quite simple.

A struct represents a fixed set of string keys and value datatypes.

Structs are not guaranteed to have exactly the field order you defined them with, but the order of their fields is identical on client and server.

You can define a valid struct Datatype using a simple table, just like luau:

local ty = light.datatypes

local some_struct = {--(1)!
    a = ty.u8,
    b = ty.i16,
    c = {
        some = ty.str(),
        thing = ty.u8
    }
}

1. Struct Merging

   Because of this design, merging structs together is as simple as writing a table merging utility:

   local function struct_merge<From, Into>(from: From, into: Into): Into & From
       local output = table.clone(into)
       for field_name, field_type in from do
           assert(not output[field_name], `Duplicate Field Name: {field_name}`)
           output[field_name] = field_type
       end
       return output
   end
   

Using the above table syntax will behave the same as passing the table into the API shown below.

function light.datatypes.struct

function struct<Fields>(--Sync--
    map: Fields, -- { [string]: Datatype }
): (Datatype<Fields>)