Reflex.FunctorMaybe

This module defines the FunctorMaybe class, which extends Functors with the ability to delete values.

Documentation

class FunctorMaybe f where

A class for values that combines filtering and mapping using Maybe. Morally, FunctorMaybe ~ KleisliFunctor Maybe. Also similar is the Witherable typeclass, but it requires Foldable f and Traverable f, and e.g. Event is instance of neither.

A definition of fmapMaybe must satisfy the following laws:

identity

fmapMaybe Just ≡ id

composition

fmapMaybe (f <=< g) ≡ fmapMaybe f . fmapMaybe g

Methods

fmapMaybe :: (a -> Maybe b) -> f a -> f b

Combined mapping and filtering function.

Instances

FunctorMaybe []

fmapMaybe = mapMaybe

Defined in Reflex.FunctorMaybe

Methods

fmapMaybe :: (a -> Maybe b) -> [a] -> [b]

FunctorMaybe Maybe

@fmapMaybe = (=<<)

Defined in Reflex.FunctorMaybe

Methods

fmapMaybe :: (a -> Maybe b) -> Maybe a -> Maybe b

FunctorMaybe IntMap

Defined in Reflex.FunctorMaybe

Methods

fmapMaybe :: (a -> Maybe b) -> IntMap a -> IntMap b

FunctorMaybe (Map k)

Defined in Reflex.FunctorMaybe

Methods

fmapMaybe :: (a -> Maybe b) -> Map k a -> Map k b

FunctorMaybe (MonoidalMap k)

Defined in Data.AppendMap

Methods

fmapMaybe :: (a -> Maybe b) -> MonoidalMap k a -> MonoidalMap k b

HasSpiderTimeline x => FunctorMaybe (Event x)

Defined in Reflex.Spider.Internal

Methods

fmapMaybe :: (a -> Maybe b) -> Event x a -> Event x b

Reflex t => FunctorMaybe (Event t)

Defined in Reflex.Class

Methods

fmapMaybe :: (a -> Maybe b) -> Event t a -> Event t b