Data.Monoid.Endo

Utilities for Endo data type from Data.Monoid module.

Endo

type E a = a -> a

Type synonym for endomorphsm; it can be used to simplify type signatures.

newtype Endo a :: * -> *

The monoid of endomorphisms under composition.

Constructors

Endo

Fields

• appEndo :: a -> a

Instances

Generic (Endo a)

Associated Types

type Rep (Endo a) :: * -> *

Methods

from :: Endo a -> Rep (Endo a) x

to :: Rep (Endo a) x -> Endo a

Semigroup (Endo a)

Methods

(<>) :: Endo a -> Endo a -> Endo a

sconcat :: NonEmpty (Endo a) -> Endo a

stimes :: Integral b => b -> Endo a -> Endo a

Monoid (Endo a)

Methods

mempty :: Endo a

mappend :: Endo a -> Endo a -> Endo a

mconcat :: [Endo a] -> Endo a

Default (Endo a)

Methods

def :: Endo a

FromEndo (Endo a)

Associated Types

type EndoOperatedOn (Endo a) :: *

Methods

fromEndo :: Endo (EndoOperatedOn (Endo a)) -> Endo a

fromDualEndo :: Dual (Endo (EndoOperatedOn (Endo a))) -> Endo a

AnEndo (Endo a)

Associated Types

type EndoOperatesOn (Endo a) :: *

Methods

anEndo :: Endo a -> Endo (EndoOperatesOn (Endo a))

aDualEndo :: Endo a -> Dual (Endo (EndoOperatesOn (Endo a)))

FoldEndoArgs (Endo a)

Associated Types

type ResultOperatesOn (Endo a) :: *

type Result (Endo a) :: *

Methods

foldEndoArgs :: Endo (ResultOperatesOn (Endo a)) -> Endo a

dualFoldEndoArgs :: Dual (Endo (ResultOperatesOn (Endo a))) -> Endo a

type Rep (Endo a)

type Rep (Endo a) = D1 (MetaData "Endo" "Data.Monoid" "base" True) (C1 (MetaCons "Endo" PrefixI True) (S1 (MetaSel (Just Symbol "appEndo") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (a -> a))))

type EndoOperatedOn (Endo a)

type EndoOperatedOn (Endo a) = a

type EndoOperatesOn (Endo a)

type EndoOperatesOn (Endo a) = a

type ResultOperatesOn (Endo a)

type ResultOperatesOn (Endo a) = a

type Result (Endo a)

type Result (Endo a) = Endo a

runEndo :: a -> Endo a -> a

Flipped version of appEndo.

mapEndo :: (E a -> E b) -> Endo a -> Endo b

Transform function wrapped in Endo.

mapEndo2 :: (E a -> E b -> E c) -> Endo a -> Endo b -> Endo c

Variation of mapEndo for functions with arity two.

liftEndo :: Functor f => Endo a -> Endo (f a)

Apply fmap to function wrapped in Endo. It's a short hand for mapEndo fmap.

Lens

endo :: Functor f => (E a -> f (E b)) -> Endo a -> f (Endo b)

Lens for Endo. In terms of lens package it would have type:

endo :: Lens (Endo a) (Endo b) (E a) (E b)

For details see lens package.