Type Aliases

SerializableProperty uses several type aliases to improve code readability and provide clear type hints for callback functions.

Type Variable

jangada.serialization.T = TypeVar('T')

Type variable representing the type of the property value.

Type variable representing the type of the property value.

Callable Type Aliases

jangada.serialization.DefaultCallable

Callable that produces a default value for a property.

Parameters:

instanceobject

The instance for which to generate the default value.

Returns:

T

The default value.

Callable that produces a default value for a property.

Signature: (instance: object) -> T

Parameters:

• instance (object) – The instance for which to generate the default value

Returns:

The default value of type T

Example:

def make_default_list(instance: object) -> list:
    return []

class MyClass:
    items = SerializableProperty(default=make_default_list)

alias of Callable[[object], T]

jangada.serialization.Observer

Callable that observes property value changes.

Parameters:

instanceobject

The instance whose property changed.

old_valueT

The previous value of the property.

new_valueT

The new value of the property.

Returns:

None

Callable that observes property value changes.

Signature: (instance: object, old_value: T, new_value: T) -> None

Parameters:

• instance (object) – The instance whose property changed

• old_value (T) – The previous value of the property

• new_value (T) – The new value of the property

Returns:

None

Example:

def log_changes(instance: object, old: Any, new: Any) -> None:
    print(f"Value changed from {old} to {new}")

class MyClass:
    value = SerializableProperty(observers={log_changes})

alias of Callable[[object, T, T], None]

jangada.serialization.Parser

Callable that parses and validates property values.

Parameters:

instanceobject

The instance for which to parse the value.

valueAny

The raw value to parse.

Returns:

T

The parsed and validated value.

Callable that parses and validates property values.

Signature: (instance: object, value: Any) -> T

Parameters:

• instance (object) – The instance for which to parse the value

• value (Any) – The raw value to parse

Returns:

The parsed and validated value of type T

Raises:

Any exception raised during parsing propagates to the caller

Example:

def parse_positive(instance: object, value: Any) -> float:
    result = float(value)
    if result <= 0:
        raise ValueError("Value must be positive")
    return result

class MyClass:
    temperature = SerializableProperty(parser=parse_positive)

alias of Callable[[object, Any], T]

jangada.serialization.Postinitializer

Callable that performs post-initialization setup.

Parameters:

instanceobject

The instance to initialize.

Returns:

None

Callable that performs post-initialization setup.

Signature: (instance: object) -> None

Parameters:

• instance (object) – The instance to initialize

Returns:

None

Notes:

The Postinitializer is called once after the property is first set or accessed. It runs after the value has been stored and observers have been called.

Example:

def setup_data(instance: object) -> None:
    print("Loading expensive data...")
    if instance.data is None:
        instance.data = load_from_disk()

class MyClass:
    data = SerializableProperty(postPostinitializer=setup_data)

alias of Callable[[object], T]