def _min_max(self, fa: F[A], f: Callable[[A], int], pred: Callable[[int, int], int]) -> Maybe[int]:
def folder(z: Maybe[A], a: A) -> Maybe[int]:
return (
z.map(lambda b: b if pred(f(b), f(a)) else a)
.or_else(Just(a))
)
return self.fold_left(fa, Empty())(folder)
def _drain_find(self, abort: Callable[[A], bool]) -> Maybe[A]:
culprit = Empty()
def gen() -> Generator:
nonlocal culprit
while True:
try:
el = next(self.source)
yield el
if abort(el):
culprit = Just(el)
break
except StopIteration:
break
drained = List.wrap(list(gen()))
self.strict = self.strict + drained
return culprit
def to_maybe(self, fa: Either[A, B]) -> Maybe[A]:
return Just(fa.value) if fa.is_right else Empty()