Copyright	(C) 2012 Edward Kmett
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	provisional
Portability	GADTs, Rank2Types
Safe Haskell	Safe
Language	Haskell2010

Control.Alternative.Free

Description

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

Synopsis

newtype Alt f a = Alt {
- alternatives :: [AltF f a]
}
data AltF f a where
- Ap :: f a -> Alt f (a -> b) -> AltF f b
- Pure :: a -> AltF f a
runAlt :: forall f g a. Alternative g => (forall x. f x -> g x) -> Alt f a -> g a
liftAlt :: f a -> Alt f a
hoistAlt :: (forall a. f a -> g a) -> Alt f b -> Alt g b

Documentation

newtype Alt f a #

Constructors

Alt
Fields alternatives :: [AltF f a]

Instances

Instances details

Functor (Alt f) #
Instance details Defined in Control.Alternative.Free Methods fmap :: (a -> b) -> Alt f a -> Alt f b # (<$) :: a -> Alt f b -> Alt f a #
Applicative (Alt f) #
Instance details Defined in Control.Alternative.Free Methods pure :: a -> Alt f a # (<>) :: Alt f (a -> b) -> Alt f a -> Alt f b # liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c # (>) :: Alt f a -> Alt f b -> Alt f b # (<*) :: Alt f a -> Alt f b -> Alt f a #
Alternative (Alt f) #
Instance details Defined in Control.Alternative.Free Methods empty :: Alt f a # (<\|>) :: Alt f a -> Alt f a -> Alt f a # some :: Alt f a -> Alt f [a] # many :: Alt f a -> Alt f [a] #
Alt (Alt f) #
Instance details Defined in Control.Alternative.Free Methods (<!>) :: Alt f a -> Alt f a -> Alt f a # some :: Applicative (Alt f) => Alt f a -> Alt f [a] # many :: Applicative (Alt f) => Alt f a -> Alt f [a] #
Apply (Alt f) #
Instance details Defined in Control.Alternative.Free Methods (<.>) :: Alt f (a -> b) -> Alt f a -> Alt f b # (.>) :: Alt f a -> Alt f b -> Alt f b # (<.) :: Alt f a -> Alt f b -> Alt f a # liftF2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c #
Semigroup (Alt f a) #
Instance details Defined in Control.Alternative.Free Methods (<>) :: Alt f a -> Alt f a -> Alt f a # sconcat :: NonEmpty (Alt f a) -> Alt f a # stimes :: Integral b => b -> Alt f a -> Alt f a #
Monoid (Alt f a) #
Instance details Defined in Control.Alternative.Free Methods mempty :: Alt f a # mappend :: Alt f a -> Alt f a -> Alt f a # mconcat :: [Alt f a] -> Alt f a #

data AltF f a where #

Constructors

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

Instances

Instances details

Functor (AltF f) #
Instance details Defined in Control.Alternative.Free Methods fmap :: (a -> b) -> AltF f a -> AltF f b # (<$) :: a -> AltF f b -> AltF f a #
Applicative (AltF f) #
Instance details Defined in Control.Alternative.Free Methods pure :: a -> AltF f a # (<>) :: AltF f (a -> b) -> AltF f a -> AltF f b # liftA2 :: (a -> b -> c) -> AltF f a -> AltF f b -> AltF f c # (>) :: AltF f a -> AltF f b -> AltF f b # (<*) :: AltF f a -> AltF f b -> AltF f a #

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 :: f a -> Alt f a #

A version of lift that can be used with any 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.