Safe Haskell	None
Language	Haskell2010

Optics.Internal.Fold

Description

Internal implementation details of folds.

This module is intended for internal use only, and may change without warning in subsequent releases.

Synopsis

foldVL__ :: (Bicontravariant p, Traversing p) => (forall f. Applicative f => (a -> f u) -> s -> f v) -> Optic__ p i i s t a b
folded__ :: (Bicontravariant p, Traversing p, Foldable f) => Optic__ p i i (f a) (f b) a b
foldring__ :: (Bicontravariant p, Traversing p) => (forall f. Applicative f => (a -> f u -> f u) -> f v -> s -> f w) -> Optic__ p i i s t a b
data Leftmost a
- = LPure
- | LLeaf a
- | LStep (Leftmost a)
getLeftmost :: Leftmost a -> Maybe a
data Rightmost a
- = RPure
- | RLeaf a
- | RStep (Rightmost a)
getRightmost :: Rightmost a -> Maybe a

Documentation

foldVL__ :: (Bicontravariant p, Traversing p) => (forall f. Applicative f => (a -> f u) -> s -> f v) -> Optic__ p i i s t a b Source #

Internal implementation of foldVL.

Internal implementation of folded.

foldring__ :: (Bicontravariant p, Traversing p) => (forall f. Applicative f => (a -> f u -> f u) -> f v -> s -> f w) -> Optic__ p i i s t a b Source #

Internal implementation of foldring.

Used for headOf and iheadOf.

Constructors

Instances

Semigroup (Leftmost a) Source #
Instance details Defined in Optics.Internal.Fold Methods (<>) :: Leftmost a -> Leftmost a -> Leftmost a # sconcat :: NonEmpty (Leftmost a) -> Leftmost a # stimes :: Integral b => b -> Leftmost a -> Leftmost a #
Monoid (Leftmost a) Source #
Instance details Defined in Optics.Internal.Fold Methods mempty :: Leftmost a # mappend :: Leftmost a -> Leftmost a -> Leftmost a # mconcat :: [Leftmost a] -> Leftmost a #

Extract the Leftmost element. This will fairly eagerly determine that it can return Just the moment it sees any element at all.

Used for lastOf and ilastOf.

Constructors

Instances

Semigroup (Rightmost a) Source #
Instance details Defined in Optics.Internal.Fold Methods (<>) :: Rightmost a -> Rightmost a -> Rightmost a # sconcat :: NonEmpty (Rightmost a) -> Rightmost a # stimes :: Integral b => b -> Rightmost a -> Rightmost a #
Monoid (Rightmost a) Source #
Instance details Defined in Optics.Internal.Fold Methods mempty :: Rightmost a # mappend :: Rightmost a -> Rightmost a -> Rightmost a # mconcat :: [Rightmost a] -> Rightmost a #

Extract the Rightmost element. This will fairly eagerly determine that it can return Just the moment it sees any element at all.