Modulerelude-1.2.0.0Haskell2010

Relude.Extra.Bifunctor

SPDX-License-Identifier : MIT Maintainer : Kowainik xrom.xkov@gmail.com Stability : Stable Portability : Portable

Useful combinators for bifunctors inside functors. This set of functions is useful when you want to work with types like these ones:

foo :: IO (Either a b)
bar :: IO (a, b)

baz :: Maybe (Either a b)
qux :: Maybe (a, b)

doo :: (a, a)
dee :: Either a a

valuebimapBoth :: Bifunctor f => (a -> b) -> f a a -> f b b

Maps a function over both elements of a bifunctor.

Example2 expressions

>>> bimapBoth length ([True], [False, True])(1,2)>>> map (bimapBoth not) [Left True, Right False][Left False,Right True]

valuebimapF

Fmaps functions for nested bifunctor. Short for fmap (bimap f g).

Example1 expression

>>> bimapF not length $ Just (False, ['a', 'b'])Just (True,2)

valuefirstF :: (Functor f, Bifunctor p) => (a -> c) -> f (p a b) -> f (p c b)

Short for fmap . first.

Example1 expression

>>> firstF not $ Just (False, ['a', 'b'])Just (True,"ab")

valuesecondF :: (Functor f, Bifunctor p) => (b -> d) -> f (p a b) -> f (p a d)

Short for fmap . second.

Example1 expression

>>> secondF length  $ Just (False, ['a', 'b'])Just (False,2)