Packable

Packable()

Structural protocol for packable sample types.

This protocol allows classes decorated with @packable to be recognized as valid types for lens transformations and schema operations, even though the decorator doesn’t change the class’s nominal type at static analysis time.

Both PackableSample subclasses and @packable-decorated classes satisfy this protocol structurally.

The protocol captures the full interface needed for: - Lens type transformations (as_wds, from_data) - Schema publishing (class introspection via dataclass fields) - Serialization/deserialization (packed, from_bytes)

Examples

>>> @packable
... class MySample:
...     name: str
...     value: int
...
>>> def process(sample_type: Type[Packable]) -> None:
...     # Type checker knows sample_type has from_bytes, packed, etc.
...     instance = sample_type.from_bytes(data)
...     print(instance.packed)

Attributes

Name	Description
as_wds	WebDataset-compatible representation with key and msgpack.
packed	Pack this sample’s data into msgpack bytes.

Methods

Name	Description
from_bytes	Create instance from raw msgpack bytes.
from_data	Create instance from unpacked msgpack data dictionary.

from_bytes

Packable.from_bytes(bs)

Create instance from raw msgpack bytes.

from_data

Packable.from_data(data)

Create instance from unpacked msgpack data dictionary.