multirec-0.2: Generic programming with systems of recursive datatypes Source code Contents Index

Generics.MultiRec.HFunctor Portability non-portable Stability experimental Maintainer generics@haskell.org

Contents Generic map

Description

The definition of functorial map.

Synopsis

class HFunctor f where hmapA :: Applicative a => (forall ix. Ix s ix => s ix -> r ix -> a (r' ix)) -> f s r ix -> a (f s r' ix) hmap :: HFunctor f => (forall ix. Ix s ix => s ix -> r ix -> r' ix) -> f s r ix -> f s r' ix hmapM :: (HFunctor f, Monad m) => (forall ix. Ix s ix => s ix -> r ix -> m (r' ix)) -> f s r ix -> m (f s r' ix)

Generic map

class HFunctor f where Source

Methods hmapA :: Applicative a => (forall ix. Ix s ix => s ix -> r ix -> a (r' ix)) -> f s r ix -> a (f s r' ix) Source Instances HFunctor U HFunctor (K x) HFunctor (I xi) HFunctor f => HFunctor (C c f) HFunctor f => HFunctor (f :>: ix) (HFunctor f, HFunctor g) => HFunctor (f :*: g) (HFunctor f, HFunctor g) => HFunctor (f :+: g)

hmap :: HFunctor f => (forall ix. Ix s ix => s ix -> r ix -> r' ix) -> f s r ix -> f s r' ix Source

The function hmap takes a functor f. All the recursive instances in that functor are wrapped by an application of r. The argument to hmap takes a function that transformes r occurrences into r' occurrences, for every ix. In order to associate the index ix with the correct system s, the argument to hmap is additionally parameterized by a witness of type s ix.

hmapM :: (HFunctor f, Monad m) => (forall ix. Ix s ix => s ix -> r ix -> m (r' ix)) -> f s r ix -> m (f s r' ix) Source

Monadic version of hmap.

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