Serialization

Ferlium serializes typed values through a dynamic data model named DataValue. The Serialize trait converts a typed value to DataValue, and Deserialize converts a DataValue back to an expected typed value.

let data = serialize({ host: "localhost", port: 8080 });
let config: { host: string, port: int } = deserialize(data);

Data Values

DataValue is an interchange tree used by serialization codecs:

DataValue::Null
DataValue::Unit
DataValue::Bool(true)
DataValue::Int(1)
DataValue::Float(1.5)
DataValue::String("hello")
DataValue::Array([DataValue::Int(1), DataValue::Int(2)])
DataValue::Tuple([DataValue::Int(1), DataValue::String("x")])
DataValue::Record([("host", DataValue::String("localhost"))])
DataValue::Set([DataValue::String("a"), DataValue::String("b")])
DataValue::Map([(DataValue::String("a"), DataValue::Int(1))])
DataValue::Variant { name: "Some", payload: DataValue::Tuple([DataValue::Int(1)]) }

Null represents external null data, such as JSON null. Unit represents the Ferlium value ().

Arrays, tuples, records, sets, maps, and variants keep distinct shapes in DataValue. JSON may still encode several of these as arrays or objects because JSON has fewer data shapes.

JSON

JSON is a codec over DataValue.

let text = json_encode({ host: "localhost", port: 8080 });
let config: { host: string, port: int } = json_decode(text);

JSON input maps to DataValue as follows:

• null becomes Null
• booleans, numbers, and strings become Bool, Int or Float, and String
• arrays become Array
• objects become Record

Maps are encoded to JSON as arrays of key-value pairs. This keeps the representation valid even when keys are not strings.

Ferlium Data Text

Ferlium data text is a human-readable codec over DataValue. It accepts inert value syntax only; it does not evaluate Ferlium expressions.

let text = data_text_encode({
    host: "localhost",
    port: 8080,
    retry: Some(3),
});

let config: { host: string, port: int, retry: Option<int> } = data_text_decode(text);

Data text supports:

• null, (), booleans, numbers, and strings
• arrays: [1, 2, 3]
• tuples: (1, "x")
• records: { host: "localhost", port: 8080 }
• variants: None, Some(1)
• sets: set { 1, 2, 3 }
• maps: map { "a" => 1, "b" => 2 }
• comments and trailing commas

It does not support operators, function calls, bindings, control flow, imports, or string interpolation. The expected target type guides deserialization.

What comes next

The next chapter introduces effects, showing how Ferlium tracks reading, writing, and failure alongside ordinary values.