Copyright	(C) 2012-2016 Edward Kmett
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	non-portable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Lens.Internal.Fold

Contents

Monoids for folding
Semigroups for folding

Description

Synopsis

newtype Folding f a = Folding {
- getFolding :: f a
}
newtype Traversed a f = Traversed {
- getTraversed :: f a
}
newtype TraversedF a f = TraversedF {
- getTraversedF :: f a
}
newtype Sequenced a m = Sequenced {
- getSequenced :: m a
}
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
data ReifiedMonoid a = ReifiedMonoid {
- reifiedMappend :: a -> a -> a
- reifiedMempty :: a
}
newtype NonEmptyDList a = NonEmptyDList {
- getNonEmptyDList :: [a] -> NonEmpty a
}

Monoids for folding

newtype Folding f a Source #

A Monoid for a Contravariant Applicative .

Constructors

Folding
Fields getFolding :: f a

Instances

Instances details

( Contravariant f, Applicative f) => Semigroup ( Folding f a) Source #
Instance details Defined in Control.Lens.Internal.Fold Methods (<>) :: Folding f a -> Folding f a -> Folding f a Source # sconcat :: NonEmpty ( Folding f a) -> Folding f a Source # stimes :: Integral b => b -> Folding f a -> Folding f a Source #
( Contravariant f, Applicative f) => Monoid ( Folding f a) Source #
Instance details Defined in Control.Lens.Internal.Fold Methods mempty :: Folding f a Source # mappend :: Folding f a -> Folding f a -> Folding f a Source # mconcat :: [ Folding f a] -> Folding f a Source #

newtype Traversed a f Source #

Used internally by traverseOf_ and the like.

The argument a of the result should not be used!

Constructors

Traversed
Fields getTraversed :: f a

Instances

Instances details

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

newtype TraversedF a f Source #

Used internally by traverse1Of_ and the like.

Since: 4.16

Constructors

TraversedF
Fields getTraversedF :: f a

Instances

Instances details

Apply f => Semigroup ( TraversedF a f) Source #
Instance details Defined in Control.Lens.Internal.Fold Methods (<>) :: TraversedF a f -> TraversedF a f -> TraversedF a f Source # sconcat :: NonEmpty ( TraversedF a f) -> TraversedF a f Source # stimes :: Integral b => b -> TraversedF a f -> TraversedF a f Source #
( Apply f, Applicative f) => Monoid ( TraversedF a f) Source #
Instance details Defined in Control.Lens.Internal.Fold Methods mempty :: TraversedF a f Source # mappend :: TraversedF a f -> TraversedF a f -> TraversedF a f Source # mconcat :: [ TraversedF a f] -> TraversedF a f Source #

newtype Sequenced a m Source #

Used internally by mapM_ and the like.

The argument a of the result should not be used!

See 4.16 Changelog entry for the explanation of "why not Apply f =>"?

Constructors

Sequenced
Fields getSequenced :: m a

Instances

Instances details

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

data Leftmost a Source #

Used for firstOf .

Constructors

LPure
LLeaf a
LStep ( Leftmost a)

Instances

Instances details

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

getLeftmost :: Leftmost a -> Maybe a Source #

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

data Rightmost a Source #

Used for lastOf .

Constructors

RPure
RLeaf a
RStep ( Rightmost a)

Instances

Instances details

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

getRightmost :: Rightmost a -> Maybe a Source #

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

data ReifiedMonoid a Source #

Constructors

ReifiedMonoid
Fields reifiedMappend :: a -> a -> a reifiedMempty :: a

Semigroups for folding

newtype NonEmptyDList a Source #

Constructors

NonEmptyDList
Fields getNonEmptyDList :: [a] -> NonEmpty a

Instances

Instances details

Semigroup ( NonEmptyDList a) Source #
Instance details Defined in Control.Lens.Internal.Fold Methods (<>) :: NonEmptyDList a -> NonEmptyDList a -> NonEmptyDList a Source # sconcat :: NonEmpty ( NonEmptyDList a) -> NonEmptyDList a Source # stimes :: Integral b => b -> NonEmptyDList a -> NonEmptyDList a Source #