def traverse(gap: Applicative[G], fa: Kind1[Option, A],\
f: Func1[A, Kind1[G, B]]) -> Kind2[G, Option, B]:
if dekind(fa).is_empty():
return cast(Kind2[G, Option, B], gap.pure(Nothing()))
else:
ff: Func1[B, Option[B]] = Some
return gap.map(f(dekind(fa).get), ff)
def reduce_left_to_option(
cls, fa: Kind1[F, A], f: Func1[A, B], g: Func2[B, A, B]) -> "Option.Option[B]":
from tats.data.Option import Option, Nothing, Some
conv: Func2[
Option[B], A,
Option[B]] = lambda acc, el: Some(f(el)) if acc.is_empty() else Some(g(acc.get, el))
return cls.fold_left(fa, Nothing(), conv)
def test_foreach(self):
def _raise(_):
raise Exception
with raises(Exception):
Some(1).foreach(_raise)
Nothing().foreach(_raise)
def test_with_filter(self):
assert Some(1).with_filter(lambda x: x == 1).map(lambda x: x * 2) == Some(2)
assert Nothing()\
.with_filter(lambda x: x == 1)\
.map(lambda x: x * 2) == Nothing()
assert Some(1)\
.with_filter(lambda x: x == 2)\
.map(lambda x: x * 2) == Nothing()
assert Some(1)\
.with_filter(lambda x: x == 1)\
.flat_map(lambda x: Some(x * 2)) == Some(2)
assert Nothing()\
.with_filter(lambda x: x == 1)\
.flat_map(lambda x: Some(x * 2)) == Nothing()
assert Some(1) \
.with_filter(lambda x: x == 2) \
.flat_map(lambda x: Some(x * 2)) == Nothing()
def _raise(_):
raise Exception
with raises(Exception):
Some(1) \
.with_filter(lambda x: x == 1) \
.foreach(_raise)
Nothing() \
.with_filter(lambda x: x == 1) \
.foreach(_raise)
Some(1) \
.with_filter(lambda x: x == 2) \
.foreach(_raise)
assert Some(1)\
.with_filter(lambda x: x == 1)\
.with_filter(lambda x: x % 2 == 1)\
.map(lambda x: x * 2) == Some(2)
assert Nothing() \
.with_filter(lambda x: x == 1) \
.with_filter(lambda x: x % 2 == 1) \
.map(lambda x: x * 2) == Nothing()
assert Some(1) \
.with_filter(lambda x: x == 2) \
.with_filter(lambda x: x % 2 == 1) \
.map(lambda x: x * 2) == Nothing()
def test_syntax(self):
assert TList([1, 2, 3]).eqv(TList([1, 2, 3]))
assert TList([1, 2, 3]).neqv(TList([1, 2]))
assert TList([1, 2]).map(lambda x: x * 2) == TList([2, 4])
assert TList([1, 2]).product_r(TList([3, 4])) == TList([3, 4, 3, 4])
assert TList([1, 2]).product_l(TList([3, 4])) == TList([1, 1, 2, 2])
assert TList([1, 2]).flat_map(lambda x: TList([x, x * 2])) == TList([1, 2, 2, 4])
assert TList([1, 2]).combine(TList([3, 4])) == TList([1, 2, 3, 4])
assert TList([1, 2]) + TList([3, 4]) == TList([1, 2, 3, 4])
assert TList([1, 2]) + TList([3, 4]) == TList([1, 2, 3, 4])
assert TList([]).is_empty
assert not TList([1, 2]).is_empty
assert TList([1, 2, 3]).fold_left(0, lambda a, b: a + b) == 6
assert TList([1, 2, 3]).reduce_left_to_option(str, lambda a, b: a + str(b)) == Some("123")
assert TList([]).reduce_left_to_option(str, lambda a, b: a + str(b)) == Nothing()
assert TList([1, 2, 3]).reduce_left_option(lambda a, b: a + b) == Some(6)
assert TList([]).reduce_left_option(lambda a, b: a + b) == Nothing()
assert TList([1, 2, 3]).to_tlist() == TList([1, 2, 3])
assert TList([1, 2, 3]).map2(TList([4, 5]), lambda a, b: a * b) == TList([4, 5, 8, 10, 12, 15])
assert TList([1, 2, 3]).product(TList([4, 5 ])) ==\
TList([(1, 4), (1, 5), (2, 4), (2, 5), (3, 4), (3, 5)])
assert TList([1, 2, 3]).traverse(OptionInstance(), Some) == Some(TList([1, 2, 3]))
assert TList([1, 2, 3])\
.traverse(OptionInstance(), lambda x: Nothing() if x > 2 else Some(x)) == Nothing()
assert TList([Some(1), Some(2), Some(3)]).sequence(OptionInstance()) == Some(TList([1, 2, 3]))
assert TList([Some(1), Nothing(), Some(3)]).sequence(OptionInstance()) == Nothing()
assert TList([1, 2, 3]).flat_traverse(OptionInstance(), lambda x: Some(TList([x, x + 1]))) == \
Some(TList([1, 2, 2, 3, 3, 4]))
assert TList([1, 2, 3]).flat_traverse(
OptionInstance(), lambda x: Some(TList([x, x + 1])) if x < 2 else Nothing()) == Nothing()
assert TList.var(1, 2, 3).map_filter(lambda a: Some(a) if a < 3 else Nothing()) == \
TList.var(1, 2)
assert TList.var(1, 2, 3).collect(PartialFunc.cs(Case.v(1, "a"), Case.v(2, "b"))) == \
TList.var("a", "b")
assert TList.var(1, 2, 3).filter(lambda a: a < 3) == TList.var(1, 2)
assert TList.var(1, 2, 3).filter_not(lambda a: a < 3) == TList.var(3)
def test_fold(self):
assert Some(1).fold("a", str) == "1"
assert Nothing().fold("a", str) == "a"
def test_filter_not(self): assert Some(1).filter_not(lambda x: x == 1) == Nothing() assert Some(1).filter_not(lambda x: x == 2) == Some(1) assert Nothing().filter_not(lambda x: x == 2) == Nothing()
def test_get(self):
assert Some(1).get == 1
with raises(ValueError):
Nothing().get
def test_get_or_else(self): assert Some(1).get_or_else(2) == 1 assert Nothing().get_or_else(2) == 2
def test_to_left(self):
assert Some(1).to_left("a") == Left(1)
assert Nothing().to_left("a") == Right("a")
def lift(self) -> "Func1[T, Option.Option[S]]":
"""lift this PartialFunc to a plain function returning an Option result"""
from tats.data.Option import Nothing, Some
return lambda a: Some(self.run(a)) if self.is_defined_at(
a) else Nothing()
def to_option(self) -> "Option.Option[R]":
from tats.data.Option import Nothing, Some
return self.fold(Func1F.const(Nothing()), Some)
def test_from_nullable(self): assert Option.from_nullable(1) == Some(1) assert Option.from_nullable(None) == Nothing()
def test_when(self): assert Option.when(True, 1) == Some(1) assert Option.when(False, 1) == Nothing()
def test_syntax(self):
assert Some(1).map(lambda x: x * 2) == Some(2)
assert Nothing().map(lambda x: x * 2) == Nothing()
assert Some(1).product_r(Some(2)) == Some(2)
assert Nothing().product_r(Some(2)) == Nothing()
assert Some(1).product_r(Nothing()) == Nothing()
assert Nothing().product_r(Nothing()) == Nothing()
assert Some(1).product_l(Some(2)) == Some(1)
assert Nothing().product_l(Some(2)) == Nothing()
assert Some(1).product_l(Nothing()) == Nothing()
assert Nothing().product_l(Nothing()) == Nothing()
assert Some(1).flat_map(lambda x: Some(x * 2)) == Some(2)
assert Some(1).flat_map(lambda x: Nothing()) == Nothing()
assert Nothing().flat_map(lambda x: Some(x * 2)) == Nothing()
assert Nothing().flat_map(lambda x: Nothing()) == Nothing()
assert Some(1).combine(IntInstance(), Some(1)) == Some(2)
assert Nothing().combine(IntInstance(), Some(1)) == Nothing()
assert Some(1).combine(IntInstance(), Nothing()) == Nothing()
assert Nothing().combine(IntInstance(), Nothing()) == Nothing()
assert Some(1).traverse(TListInstance(), lambda a: TList([a, a * 2])) == \
TList([Some(1), Some(2)])
assert Nothing().traverse(TListInstance(), lambda a: TList([a, a * 2])) == TList([Nothing()])
assert Some(1).flat_traverse(TListInstance(), lambda a: TList([Some(a), Some(a * 2)])) == \
TList([Some(1), Some(2)])
assert Some(TList([1, 2])).sequence(TListInstance()) == TList([Some(1), Some(2)])
assert Some(1).show() == "Some(a=1)"
assert Nothing().show() == "Nothing()"
def test_apply(self): assert OptionInstance.ap(Some(lambda x: x * 2), Some(1)) == Some(2) assert OptionInstance.ap(Nothing(), Some(1)) == Nothing() assert OptionInstance.ap(Some(lambda x: x * 2), Nothing()) == Nothing() assert OptionInstance.ap(Nothing(), Nothing()) == Nothing()
def test_functor(self): OptionInstance.map(Some(1), lambda x: x * 2) == Some(2) OptionInstance.map(Nothing(), lambda x: x * 2) == Nothing()
def test_eq(self): assert Some(1).eqv(Some(1)) assert not Some(1).eqv(Some(2)) assert Some(1).neqv(Nothing()) assert Nothing().neqv(Some(1)) assert Nothing().eqv(Nothing())
def test_exists(self): assert Some(1).exists(lambda x: x == 1) assert not Some(1).exists(lambda x: x == 2) assert not Nothing().exists(lambda x: x == 1)
def flat_map(fa: Kind1["Option", A],
f: Func1[A, Kind1["Option", B]]) -> Kind1["Option", B]:
return Nothing() if fa.is_empty() else f(cast(Some[A], fa).a)
def test_contains(self): assert Some(1).contains(1) assert not Nothing().contains(1)
def combine(tsemi: Semigroup[A], a: "Option[A]",
b: "Option[A]") -> "Option[A]":
if a.non_empty() and b.non_empty():
return Some(tsemi.combine(a.get, b.get))
else:
return Nothing()
def test_unless(self): assert Option.unless(True, 1) == Nothing() assert Option.unless(False, 1) == Some(1)
def test_forall(self): assert Some(1).forall(lambda x: x == 1) assert not Some(1).forall(lambda x: x == 2) assert Nothing().forall(lambda x: x == 1)
def filter_not(cls, fa: Kind1[F, A], f: Func1[A, bool]) -> Kind1[F, A]: from tats.data.Option import Some, Nothing return cls.map_filter(fa, lambda a: Nothing() if f(a) else Some(a))
def test_is_empty(self):
assert not Some("").is_empty()
assert Nothing().is_empty()
def test_non_empty(self):
assert Some("").non_empty()
assert not Nothing().non_empty()
def test_or_else(self): assert Some(1).or_else(Some(2)) == Some(1) assert Nothing().or_else(Some(2)) == Some(2) assert Some(1).or_else(Nothing()) == Some(1) assert Nothing().or_else(Nothing()) == Nothing()
def empty() -> "Option[A]":
return Nothing()
def test_lift(self):
f = PartialFunc.cs(EndoCase(str, lambda s: s + "b")).lift
assert f("a") == Some("ab")
assert f(0) == Nothing()
