multirec-0.3: Generic programming for families 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 phi f where hmapA :: Applicative a => (forall ix. phi ix -> r ix -> a (r' ix)) -> f r ix -> a (f r' ix) hmap :: HFunctor phi f => (forall ix. phi ix -> r ix -> r' ix) -> f r ix -> f r' ix hmapM :: (HFunctor phi f, Monad m) => (forall ix. phi ix -> r ix -> m (r' ix)) -> f r ix -> m (f r' ix)

Generic map

class HFunctor phi f where Source

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

hmap :: HFunctor phi f => (forall ix. phi ix -> r ix -> r' ix) -> f r ix -> f 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 family phi, the argument to hmap is additionally parameterized by a witness of type phi ix.

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

Monadic version of hmap.

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