Control.Alternative.Free

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

Documentation

data Alt f a where

The free Alternative for a Functor f.

Constructors

Pure :: a -> Alt f a

Ap :: f a -> Alt f (a -> b) -> Alt f b

Alt :: [Alt f a] -> Alt f a

Instances

Functor (Alt f)

Typeable1 f => Typeable1 (Alt f)

Applicative (Alt f)

Alternative (Alt f)

Apply (Alt f)

Monoid (Alt f a)

Semigroup (Alt f a)

runAlt :: 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 :: 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.