Safe Haskell	Safe
Language	Haskell98

Reflex.FunctorMaybe

Description

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

Synopsis

class FunctorMaybe f where
- fmapMaybe :: (a -> Maybe b) -> f a -> f b

Documentation

class FunctorMaybe f where Source #

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 Source #

Combined mapping and filtering function.

Instances

FunctorMaybe [] Source #	fmapMaybe = mapMaybe
Instance details Defined in Reflex.FunctorMaybe Methods fmapMaybe :: (a -> Maybe b) -> [a] -> [b] Source #
FunctorMaybe Maybe Source #	@fmapMaybe = (=<<)
Instance details Defined in Reflex.FunctorMaybe Methods fmapMaybe :: (a -> Maybe b) -> Maybe a -> Maybe b Source #
FunctorMaybe IntMap Source #
Instance details Defined in Reflex.FunctorMaybe Methods fmapMaybe :: (a -> Maybe b) -> IntMap a -> IntMap b Source #
FunctorMaybe (Map k) Source #
Instance details Defined in Reflex.FunctorMaybe Methods fmapMaybe :: (a -> Maybe b) -> Map k a -> Map k b Source #
FunctorMaybe (MonoidalMap k) Source #
Instance details Defined in Data.AppendMap Methods fmapMaybe :: (a -> Maybe b) -> MonoidalMap k a -> MonoidalMap k b Source #
HasSpiderTimeline x => FunctorMaybe (Event x) Source #
Instance details Defined in Reflex.Spider.Internal Methods fmapMaybe :: (a -> Maybe b) -> Event x a -> Event x b Source #
Reflex t => FunctorMaybe (Event t) Source #
Instance details Defined in Reflex.Class Methods fmapMaybe :: (a -> Maybe b) -> Event t a -> Event t b Source #