Quickstart

1. Provide source data

Use with_data for values that already exist.

from dataclasses import dataclass

from dataioc import DataDescriptor, DataIoC, IndexedData


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


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


container = DataIoC().with_data(Sensor((1, 2, 3)))

2. Define a derived value

Implement __build__ and request the descriptor.

assert container[Total] == 6
assert container[Total] == 6  # The second access uses the cache.

The container builds Total only on its first access. Its dependency, Sensor, is requested inside the builder.

3. Provide a computed source

Use a provider when a value should be calculated or replaced at runtime.

alternative = DataIoC().add_provider(Sensor, lambda _: Sensor((10, 20, 30)))
assert alternative[Total] == 60

For objects with dependencies, define __build__ instead of using a lambda.

class EstimatedSensor:
    def __build__(self, container: DataIoC) -> Sensor:
        return Sensor((10, 20, 30))


alternative = DataIoC().add_provider(Sensor, EstimatedSensor())

Continue with Core concepts or Providers.