Control.Alternative.Free

Left distributive Alternative functors for free, based on a design by Stijn van Drongelen.

Documentation

newtype Alt f a

Constructors

Alt

Fields

alternatives :: [AltF f a]

Instances

Functor f => Alternative (Alt f)

Functor f => Functor (Alt f)

Functor f => Applicative (Alt f)

Functor f => Apply (Alt f)

Functor f => Monoid (Alt f a)

Functor f => Semigroup (Alt f a)

Typeable ((* -> *) -> * -> *) Alt

data AltF f a where

Constructors

Ap :: f a -> Alt f (a -> b) -> AltF f b infixl 3

Pure :: a -> AltF f a

Instances

Functor f => Functor (AltF f)

Functor f => Applicative (AltF f)

Typeable ((* -> *) -> * -> *) AltF

runAlt :: forall f g a. Alternative g => (forall x. f x -> g x) -> Alt f a -> g a

Given a natural transformation from f to g, this gives a canonical monoidal natural transformation from Alt f to g.

liftAlt :: Functor f => f a -> Alt f a

A version of lift that can be used with just a Functor for f.

hoistAlt :: (forall a. f a -> g a) -> Alt f b -> Alt g b

Given a natural transformation from f to g this gives a monoidal natural transformation from Alt f to Alt g.