Copyright | (C) 2008-2013 Edward Kmett |
---|---|
License | BSD-style (see the file LICENSE) |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Stability | provisional |
Portability | MPTCs, fundeps |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
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.
CofreeT | |
|
(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) | |
(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) | |
Typeable ((* -> *) -> (* -> *) -> * -> *) CofreeT | |
Eq (w (CofreeF f a (CofreeT f w a))) => Eq (CofreeT f w a) | |
(Typeable (* -> *) f, Typeable (* -> *) 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 a Source
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.
a :< (f b) infixr 5 |
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) | |
Typeable ((* -> *) -> * -> * -> *) CofreeF | |
(Eq a, Eq (f b)) => Eq (CofreeF f a b) | |
(Typeable (* -> *) 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 where Source
Allows you to peel a layer off a cofree comonad.
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) |