-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | Kan extensions, the Yoneda lemma, and (co)density (co)monads -- -- Kan extensions, the Yoneda lemma, and (co)density (co)monads @package kan-extensions @version 0.2 module Data.Functor.Yoneda.Contravariant type Yoneda = YonedaT Identity yoneda :: (b -> a) -> b -> Yoneda a liftYoneda :: a -> Yoneda a lowerYoneda :: Yoneda a -> a liftYonedaT :: f a -> YonedaT f a lowerYonedaT :: Functor f => YonedaT f a -> f a lowerM :: Monad f => YonedaT f a -> f a -- | The contravariant Yoneda lemma applied to a covariant functor data YonedaT f a YonedaT :: (b -> a) -> f b -> YonedaT f a instance Adjunction f g => Adjunction (YonedaT f) (YonedaT g) instance (Functor f, Ord (f a)) => Ord (YonedaT f a) instance (Functor f, Eq (f a)) => Eq (YonedaT f a) instance (Functor f, Read (f a)) => Read (YonedaT f a) instance (Functor f, Show (f a)) => Show (YonedaT f a) instance Distributive f => Distributive (YonedaT f) instance TraversableWithKey1 f => TraversableWithKey1 (YonedaT f) instance TraversableWithKey f => TraversableWithKey (YonedaT f) instance Traversable1 f => Traversable1 (YonedaT f) instance Traversable f => Traversable (YonedaT f) instance FoldableWithKey1 f => FoldableWithKey1 (YonedaT f) instance Foldable1 f => Foldable1 (YonedaT f) instance FoldableWithKey f => FoldableWithKey (YonedaT f) instance Foldable f => Foldable (YonedaT f) instance ComonadTrans YonedaT instance Comonad w => Comonad (YonedaT w) instance Extend w => Extend (YonedaT w) instance Representable f => Representable (YonedaT f) instance (Functor f, Indexable f) => Indexable (YonedaT f) instance MonadPlus f => MonadPlus (YonedaT f) instance MonadFix f => MonadFix (YonedaT f) instance MonadTrans YonedaT instance Monad m => Monad (YonedaT m) instance Bind m => Bind (YonedaT m) instance Plus f => Plus (YonedaT f) instance Alt f => Alt (YonedaT f) instance Alternative f => Alternative (YonedaT f) instance Applicative f => Applicative (YonedaT f) instance Apply f => Apply (YonedaT f) instance Keyed f => Keyed (YonedaT f) instance Functor (YonedaT f) module Data.Functor.Yoneda type Yoneda = YonedaT Identity yoneda :: (forall b. (a -> b) -> b) -> Yoneda a runYoneda :: Yoneda a -> (a -> b) -> b liftYoneda :: a -> Yoneda a lowerYoneda :: Yoneda a -> a newtype YonedaT f a YonedaT :: (forall b. (a -> b) -> f b) -> YonedaT f a runYonedaT :: YonedaT f a -> forall b. (a -> b) -> f b liftYonedaT :: Functor f => f a -> YonedaT f a lowerYonedaT :: YonedaT f a -> f a maxF :: (Functor f, Ord (f a)) => YonedaT f a -> YonedaT f a -> YonedaT f a minF :: (Functor f, Ord (f a)) => YonedaT f a -> YonedaT f a -> YonedaT f a maxM :: (Monad m, Ord (m a)) => YonedaT m a -> YonedaT m a -> YonedaT m a minM :: (Monad m, Ord (m a)) => YonedaT m a -> YonedaT m a -> YonedaT m a instance ComonadTrans YonedaT instance Comonad w => Comonad (YonedaT w) instance Extend w => Extend (YonedaT w) instance MonadTrans YonedaT instance MonadPlus m => MonadPlus (YonedaT m) instance MonadFix m => MonadFix (YonedaT m) instance Monad m => Monad (YonedaT m) instance Bind m => Bind (YonedaT m) instance Alternative f => Alternative (YonedaT f) instance Plus f => Plus (YonedaT f) instance Alt f => Alt (YonedaT f) instance Ord (f a) => Ord (YonedaT f a) instance Eq (f a) => Eq (YonedaT f a) instance (Functor f, Read (f a)) => Read (YonedaT f a) instance Show (f a) => Show (YonedaT f a) instance Adjunction f g => Adjunction (YonedaT f) (YonedaT g) instance Representable g => Representable (YonedaT g) instance Lookup f => Lookup (YonedaT f) instance Indexable f => Indexable (YonedaT f) instance Distributive f => Distributive (YonedaT f) instance TraversableWithKey1 f => TraversableWithKey1 (YonedaT f) instance Traversable1 f => Traversable1 (YonedaT f) instance TraversableWithKey f => TraversableWithKey (YonedaT f) instance Traversable f => Traversable (YonedaT f) instance FoldableWithKey1 f => FoldableWithKey1 (YonedaT f) instance FoldableWithKey f => FoldableWithKey (YonedaT f) instance Foldable1 f => Foldable1 (YonedaT f) instance Foldable f => Foldable (YonedaT f) instance Applicative f => Applicative (YonedaT f) instance Apply f => Apply (YonedaT f) instance Keyed f => Keyed (YonedaT f) instance Functor (YonedaT f) module Data.Functor.KanExtension newtype Ran g h a Ran :: (forall b. (a -> g b) -> h b) -> Ran g h a runRan :: Ran g h a -> forall b. (a -> g b) -> h b -- | toRan and fromRan witness a higher kinded adjunction. -- from (`'Compose'` g) to Ran g toRan :: (Composition compose, Functor k) => (forall a. compose k g a -> h a) -> k b -> Ran g h b fromRan :: Composition compose => (forall a. k a -> Ran g h a) -> compose k g b -> h b composeRan :: Composition compose => Ran f (Ran g h) a -> Ran (compose f g) h a decomposeRan :: (Composition compose, Functor f) => Ran (compose f g) h a -> Ran f (Ran g h) a adjointToRan :: Adjunction f g => f a -> Ran g Identity a ranToAdjoint :: Adjunction f g => Ran g Identity a -> f a ranToComposedAdjoint :: (Composition compose, Adjunction f g) => Ran g h a -> compose h f a composedAdjointToRan :: (Composition compose, Adjunction f g, Functor h) => compose h f a -> Ran g h a data Lan g h a Lan :: (g b -> a) -> h b -> Lan g h a toLan :: (Composition compose, Functor f) => (forall a. h a -> compose f g a) -> Lan g h b -> f b fromLan :: Composition compose => (forall a. Lan g h a -> f a) -> h b -> compose f g b adjointToLan :: Adjunction f g => g a -> Lan f Identity a lanToAdjoint :: Adjunction f g => Lan f Identity a -> g a -- | lanToComposedAdjoint and composedAdjointToLan witness -- the natural isomorphism between Lan f h and Compose h -- g given f -| g lanToComposedAdjoint :: (Composition compose, Functor h, Adjunction f g) => Lan f h a -> compose h g a composedAdjointToLan :: Composition compose => Adjunction f g => compose h g a -> Lan f h a -- | composeLan and decomposeLan witness the natural -- isomorphism from Lan f (Lan g h) and Lan (f o g) -- h composeLan :: (Composition compose, Functor f) => Lan f (Lan g h) a -> Lan (compose f g) h a decomposeLan :: Composition compose => Lan (compose f g) h a -> Lan f (Lan g h) a instance Functor (Lan f g) instance Functor (Ran g h) module Control.Monad.Codensity newtype CodensityT m a CodensityT :: (forall b. (a -> m b) -> m b) -> CodensityT m a runCodensityT :: CodensityT m a -> forall b. (a -> m b) -> m b lowerCodensityT :: Monad m => CodensityT m a -> m a codensityTToAdjunction :: Adjunction f g => CodensityT g a -> g (f a) adjunctionToCodensityT :: Adjunction f g => g (f a) -> CodensityT g a instance MonadTrans CodensityT instance MonadIO m => MonadIO (CodensityT m) instance Monad (CodensityT f) instance Applicative (CodensityT f) instance Apply (CodensityT f) instance Functor (CodensityT k) -- | The density comonad for a functor. aka the comonad generated by a -- functor The ''density'' term dates back to Dubuc''s 1974 thesis. The -- term ''monad genererated by a functor'' dates back to 1972 in -- Street''s ''Formal Theory of Monads''. module Control.Comonad.Density data DensityT k a DensityT :: (k b -> a) -> k b -> DensityT k a -- | The natural isomorphism between a comonad w and the comonad generated -- by w (forwards). liftDensityT :: Comonad w => w a -> DensityT w a densityTToAdjunction :: Adjunction f g => DensityT f a -> f (g a) adjunctionToDensityT :: Adjunction f g => f (g a) -> DensityT f a instance ComonadTrans DensityT instance Comonad (DensityT f) instance Extend (DensityT f) instance Functor (DensityT f)