Source code for phantom.predicates.collection

from typing import Container
from typing import Iterable
from typing import Sized
from typing import TypeVar

from . import Predicate
from ._utils import bind_name


def contains(value: object) -> Predicate[Container]:
    """Create a new predicate that succeeds when its argument contains ``value``."""

    @bind_name(contains, value)
    def compare(container: Container) -> bool:
        return value in container

    return compare


def contained(container: Container) -> Predicate[object]:
    """
    Create a new predicate that succeeds when its argument is contained by
    ``container``.
    """

    @bind_name(contained, container)
    def compare(value: object) -> bool:
        return value in container

    return compare


def count(predicate: Predicate[int]) -> Predicate[Sized]:
    """
    Create a predicate that succeeds when the size of its argument satisfies the given
    ``predicate``.
    """

    @bind_name(count, predicate)
    def compare(sized: Sized) -> bool:
        return predicate(len(sized))

    return compare


_O = TypeVar("_O", bound=object)


def exists(predicate: Predicate[_O]) -> Predicate[Iterable]:
    """
    Create a predicate that succeeds when one or more items in its argument satisfies
    ``predicate``.
    """

    @bind_name(exists, predicate)
    def compare(iterable: Iterable) -> bool:
        return any(predicate(item) for item in iterable)

    return compare


def every(predicate: Predicate[_O]) -> Predicate[Iterable]:
    """
    Create a predicate that succeeds when all items in its argument satisfy
    ``predicate``.
    """

    @bind_name(every, predicate)
    def compare(iterable: Iterable) -> bool:
        return all(predicate(item) for item in iterable)

    return compare