[Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

[Sylvain MARIE]

The numbers module provides very useful ABC for the 'numeric tower', able to abstract away the differences between python primitives and for example numpy primitives.
I could not find any equivalent for Booleans.
However numpy defines np.bool too, so being able to have an abstract Boolean class for both python bool and numpy bool would be great.

Here is a version that I included in valid8 in the meantime

-----------------------
class Boolean(metaclass=ABCMeta):
    """
    An abstract base class for booleans, similar to what is available in numbers
    see https://docs.python.org/3.5/library/numbers.html
    """
    __slots__ = ()

    @abstractmethod
    def __bool__(self):
        """Return a builtin bool instance. Called for bool(self)."""

    @abstractmethod
    def __and__(self, other):
        """self & other"""

    @abstractmethod
    def __rand__(self, other):
        """other & self"""

    @abstractmethod
    def __xor__(self, other):
        """self ^ other"""

    @abstractmethod
    def __rxor__(self, other):
        """other ^ self"""

    @abstractmethod
    def __or__(self, other):
        """self | other"""

    @abstractmethod
    def __ror__(self, other):
        """other | self"""

    @abstractmethod
    def __invert__(self):
        """~self"""


# register bool and numpy bool_ as virtual subclasses
# so that issubclass(bool, Boolean) = issubclass(np.bool_, Boolean) = True
Boolean.register(bool)

try:
    import numpy as np
    Boolean.register(np.bool_)
except ImportError:
    # silently escape
    pass

---------------------------

If that topic was already discussed and settled in the past, please ignore this thread - apologies for not being able to find it.
Best regards

Sylvain

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