mirror of
https://github.com/correl/typesafe-monads.git
synced 2024-11-14 19:19:32 +00:00
34 lines
1 KiB
Python
34 lines
1 KiB
Python
from __future__ import annotations
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from functools import reduce
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from numbers import Number
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from typing import Any, Callable, Generic, Iterator, List, Type, TypeVar, Union
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T = TypeVar("T")
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class Monoid(Generic[T]):
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def __init__(self, value: T) -> None:
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self.value = value
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# FIXME: Other type set to Any, as the proper value (Monoid[T]) is
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# reported as incompatible with subclass implementations due to a
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# flaw in mypy: https://github.com/python/mypy/issues/1317
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def mappend(self, other: Any) -> Monoid[T]: # pragma: no cover
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raise NotImplementedError
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@classmethod
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def mzero(cls) -> Monoid[T]: # pragma: no cover
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raise NotImplementedError
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@classmethod
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def mconcat(cls, xs: Iterator[Monoid[T]]) -> Monoid[T]:
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return reduce(cls.mappend, xs, cls.mzero())
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def __eq__(self, other: object) -> bool:
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return (
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isinstance(other, Monoid)
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and type(self) == type(other)
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and self.value == other.value
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)
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__add__ = mappend
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