universum-1.5.0: Custom prelude used in Serokell

Universum.Functor.Fmap

Description

This module contains useful functions to work with Functor type class.

Functor

map :: Functor f => (a -> b) -> f a -> f b Source #

map generalized to Functor.

map

>>> map not (Just True) Just False >>> map not [True,False,True,True] [False,True,False,False]

>>>

map not (Just True)

map not [True,False,True,True]

(<<$>>) :: (Functor f, Functor g) => (a -> b) -> f (g a) -> f (g b) infixl 4 Source #

Alias for fmap . fmap. Convenient to work with two nested Functors.

fmap . fmap

>>> negate <<$>> Just [1,2,3] Just [-1,-2,-3]

negate <<$>> Just [1,2,3]