Miscellaneous Datatypes

These datatypes do not fit into the category of primitive or structural.

Custom

The Custom datatype is used as a simple way to create a custom datatype that will be used once.
If performance is essential or the datatype needs to be reused, you can create an extension datatype using the exposed internal Pack types.

-- See the API reference for the Reader and Writer libraries.
-- In this example, the datatype just represents a float64
Pack:DefineSchema(
    Pack.Custom(
        function(reader)
            return Pack.Reader.f64(reader)
        end,
        function(writer, val: number)
            Pack.Writer.alloc(writer, 4)
            Pack.Writer.f64(writer, val)
        end
    )
)

Transformer

The Transformer datatype functions as a convenient wrapper for transforming raw data into a more efficient format for encoding, and reversing that process. The format (usually a Dictionary) is how the data will be encoded by Pack. The encode function should take some data not that would not directly be accepted by format and transform it such that it can be. The decode function would then bring data encoded in that format and turn it back into the original format

encode and decode are both optional, allowing you to use the transformer for data normalization, such as filling in defaults.

type standard = {
    color: string -- Hex string
    enabled: "True" | "False"
}

Pack:DefineSchema(
    Pack.Transformer(
        Pack.Dicitonary({
            color = Pack.Color3,
            enabled = Pack.Boolean,
        }),
        function(input: standard)
            local result = {}
            result.color = Color3.FromHex(input.color)
            result.enabled = input.enabled == "True"
            
            return result
        end,
        function(input) -- The type should be inferred as the same type as the dictionary
            local result = {}
            result.color = input.color:ToHex()
            result.enabled = input.enabled and "True" or "False
    
            return result
        end
    )
)