Source code for lector.types.abc

from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass, field

import rich.repr
from pyarrow import Array


@dataclass

[docs]
class Conversion:
    """Return type of a conversion/cast."""


[docs]
    result: Array


[docs]
    meta: dict = field(default_factory=dict)




@dataclass
@rich.repr.auto

[docs]
class Converter(ABC):
    """Simple base class for dependency injection of new custom data types.

    If a proportion of values smaller than `threshold` can be successfully
    converted, the converter should return None.
    """


[docs]
    threshold: float = 1.0


    @abstractmethod

[docs]
    def convert(self, arr: Array) -> Conversion | None:
        """To be implemented in subclasses."""




@dataclass

[docs]
class ConverterRegistry:
    """Registry to manage converters."""


[docs]
    convs: dict[str, Converter] = field(default_factory=dict)



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    def register(self, registered: type) -> type:
        self.convs[registered.__name__.lower()] = registered
        return registered



[docs]
    def __getitem__(self, item: str) -> Converter:
        return self.convs[item.lower()]





[docs]
Registry = ConverterRegistry()

"""'Singleton' conversion registry."""