Indexed data

Use IndexedData when one type represents several related data groups.

from dataclasses import dataclass

from dataioc import DataDescriptor, DataIoC, IndexedData, UniqueData


@dataclass
class Sensor(IndexedData):
    values: tuple[int, ...]


container = DataIoC().with_data(
    Sensor((1, 1, 1)),
    Sensor[1]((2, 2, 2)),
)

An unindexed reference is weak inside a build. It inherits the ID of the descriptor currently being built:

class Total(DataDescriptor[int]):
    def __build__(self, container: DataIoC) -> int:
        return sum(container[Sensor].values)


assert container[Total[0]] == 3
assert container[Total[1]] == 6
assert container[Sensor] is container[Sensor[0]]

Use an indexed reference when the dependency must stay fixed:

class Offset(DataDescriptor[tuple[int, ...]]):
    def __build__(self, container: DataIoC) -> tuple[int, ...]:
        base = sum(container[Sensor[0]].values)
        return tuple(base + value for value in container[Sensor].values)


assert container[Offset[0]] == (4, 4, 4)
assert container[Offset[1]] == (5, 5, 5)

Sensor[0] is a strong reference to ID 0. Sensor[1] is a strong reference to ID 1. Outside a build, an unindexed Sensor refers to ID 0. Indexed values are wrapped with their descriptors when created as Sensor[1](...); with_data registers the underlying values under those keys.

Rebind a descriptor

index_implicit(id) preserves an existing strong ID. Subscription explicitly rebinds the descriptor and leaves the original unchanged:

original = Total[1]
assert original.index_implicit(2) is original
assert original[2].id == 2
assert original.id == 1

Share data across IDs

Ordinary Python types are shared across build IDs. Mix UniqueData into an indexed class when it should also have one shared value:

@dataclass
class Calibration(IndexedData, UniqueData):
    offset: int


container.with_data(Calibration(10))
assert container[Calibration[1]] is container[Calibration[2]]

Successfully built values are cached per key. Provider changes do not invalidate cached dependents; see Cache.

See API for IndexedData, UniqueData, and the indexed container.