| Portability | MPTCs, fundeps |
|---|---|
| Stability | provisional |
| Maintainer | Edward Kmett <ekmett@gmail.com> |
| Safe Haskell | None |
Control.Comonad.Trans.Cofree
Description
The cofree comonad transformer
- newtype CofreeT f w a = CofreeT {
- runCofreeT :: w (CofreeF f a (CofreeT f w a))
- type Cofree f = CofreeT f Identity
- cofree :: CofreeF f a (Cofree f a) -> Cofree f a
- runCofree :: Cofree f a -> CofreeF f a (Cofree f a)
- data CofreeF f a b = a :< (f b)
- class (Functor f, Comonad w) => ComonadCofree f w | w -> f where
- unwrap :: w a -> f (w a)
- headF :: CofreeF f a b -> a
- tailF :: CofreeF f a b -> f b
- coiterT :: (Functor f, Comonad w) => (w a -> f (w a)) -> w a -> CofreeT f w a
Documentation
This is a cofree comonad of some functor f, with a comonad w threaded through it at each level.
Constructors
| CofreeT | |
Fields
| |
Instances
| (Functor f, Comonad w) => ComonadCofree f (CofreeT f w) | |
| Functor f => ComonadTrans (CofreeT f) | |
| Alternative f => MonadTrans (CofreeT f) | |
| (Alternative f, Monad w) => Monad (CofreeT f w) | |
| (Functor f, Functor w) => Functor (CofreeT f w) | |
| (Typeable1 f, Typeable1 w) => Typeable1 (CofreeT f w) | |
| (Alternative f, Applicative w) => Applicative (CofreeT f w) | |
| (Foldable f, Foldable w) => Foldable (CofreeT f w) | |
| (Traversable f, Traversable w) => Traversable (CofreeT f w) | |
| (Alternative f, MonadZip f, MonadZip m) => MonadZip (CofreeT f m) | |
| (Functor f, Comonad w) => Comonad (CofreeT f w) | |
| Eq (w (CofreeF f a (CofreeT f w a))) => Eq (CofreeT f w a) | |
| (Typeable1 f, Typeable1 w, Typeable a, Data (w (CofreeF f a (CofreeT f w a))), Data a) => Data (CofreeT f w a) | |
| Ord (w (CofreeF f a (CofreeT f w a))) => Ord (CofreeT f w a) | |
| Read (w (CofreeF f a (CofreeT f w a))) => Read (CofreeT f w a) | |
| Show (w (CofreeF f a (CofreeT f w a))) => Show (CofreeT f w a) |
cofree :: CofreeF f a (Cofree f a) -> Cofree f aSource
Wrap another layer around a cofree comonad value.
cofree is a right inverse of runCofree.
runCofree . cofree == id
runCofree :: Cofree f a -> CofreeF f a (Cofree f a)Source
Unpeel the first layer off a cofree comonad value.
runCofree is a right inverse of cofree.
cofree . runCofree == id
This is the base functor of the cofree comonad transformer.
Constructors
| a :< (f b) |
Instances
| Typeable1 f => Typeable2 (CofreeF f) | |
| Traversable f => Bitraversable (CofreeF f) | |
| Functor f => Bifunctor (CofreeF f) | |
| Foldable f => Bifoldable (CofreeF f) | |
| Functor f => Functor (CofreeF f a) | |
| Foldable f => Foldable (CofreeF f a) | |
| Traversable f => Traversable (CofreeF f a) | |
| (Eq a, Eq (f b)) => Eq (CofreeF f a b) | |
| (Typeable1 f, Typeable a, Typeable b, Data a, Data (f b), Data b) => Data (CofreeF f a b) | |
| (Ord a, Ord (f b)) => Ord (CofreeF f a b) | |
| (Read a, Read (f b)) => Read (CofreeF f a b) | |
| (Show a, Show (f b)) => Show (CofreeF f a b) |
class (Functor f, Comonad w) => ComonadCofree f w | w -> f whereSource
Allows you to peel a layer off a cofree comonad.
Instances
| ComonadCofree Maybe NonEmpty | |
| ComonadCofree f w => ComonadCofree f (IdentityT w) | |
| Functor f => ComonadCofree f (Cofree f) | |
| Comonad w => ComonadCofree Identity (CoiterT w) | |
| (ComonadCofree f w, Semigroup m, Monoid m) => ComonadCofree f (TracedT m w) | |
| ComonadCofree f w => ComonadCofree f (StoreT s w) | |
| ComonadCofree f w => ComonadCofree f (EnvT e w) | |
| (Functor f, Comonad w) => ComonadCofree f (CofreeT f w) | |
| ComonadCofree (Const b) ((,) b) |