category-extras-0.53.0: Various modules and constructs inspired by category theory Source code Contents Index

Control.Monad.Free Portability portable Stability experimental Maintainer Edward Kmett <ekmett@gmail.com>

Description

See http://wwwtcs.inf.tu-dresden.de/%7Evoigt/mpc08.pdf for the background on rep, abs and improve and their use. NB: the C type in that paper is just the right Kan extension of a monad along itself, also known as the monad generated by a functor: http://www.tac.mta.ca/tac/volumes/10/19/10-19.ps

Documentation

module Control.Monad.Parameterized

type PFree = PAp Either Source

type Free f = Fix (PFree f) Source

runFree :: Free f a -> Either a (f (Free f a)) Source

free :: Either a (f (Free f a)) -> Free f a Source

class (Functor f, Monad m) => MonadFree f m | m -> f where Source

Methods inFree :: f (m a) -> m a Source Instances Functor f => MonadFree f (Free f) MonadFree f m => MonadFree f (CoYoneda m) MonadFree f m => MonadFree f (Yoneda m) MonadFree f m => MonadFree f (Codensity m) MonadFree f m => MonadFree f (ReaderT e m)

class MonadFree f m => RunMonadFree f m | m -> f where Source

Methods cataFree :: (c -> a) -> Algebra f a -> m c -> a Source Instances Functor f => RunMonadFree f (Free f) RunMonadFree f m => RunMonadFree f (CoYoneda m) RunMonadFree f m => RunMonadFree f (Yoneda m) RunMonadFree f m => RunMonadFree f (Codensity m)

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