Fresnel.OptionalFold

Optional folds

type OptionalFold s a = forall p. IsOptionalFold p => Optic' p s a

class (IsOptional p, IsGetter p) => IsOptionalFold p

Instances

(Traversable f, Contravariant f) => IsOptionalFold (OptionalStar f)

Defined in Fresnel.OptionalFold.Internal

Monoid r => IsOptionalFold (Forget r :: Type -> Type -> Type)

Defined in Fresnel.OptionalFold.Internal

(Applicative f, Traversable f, Contravariant f) => IsOptionalFold (Star f)

Defined in Fresnel.OptionalFold.Internal

Construction

folding :: (s -> Maybe a) -> OptionalFold s a

filtered :: (a -> Bool) -> OptionalFold a a

Elimination

is :: OptionalFold s a -> s -> Bool

isn't :: OptionalFold s a -> s -> Bool

traverseOf_ :: Functor f => OptionalFold s a -> (forall x. x -> f x) -> (a -> f u) -> s -> f ()

newtype Failover s a

Constructors

Failover

Fields

• getFailover :: OptionalFold s a

Instances

Semigroup (Failover s a)

Defined in Fresnel.OptionalFold

Methods

(<>) :: Failover s a -> Failover s a -> Failover s a

sconcat :: NonEmpty (Failover s a) -> Failover s a

stimes :: Integral b => b -> Failover s a -> Failover s a