TypeCompose-0.3: Type composition classes & instances Source code Contents Index

Data.RefMonad Portability MPTC Stability experimental Maintainer conal@conal.net

Description

Monads with references, taken from John Hughes's Global Variables in Haskell (http://citeseer.ist.psu.edu/473734.html).

Synopsis

class Monad m => RefMonad m r | m -> r, r -> m where newRef :: a -> m (r a) readRef :: r a -> m a writeRef :: r a -> a -> m () modifyRef :: RefMonad m r => r a -> (a -> a) -> m ()

Documentation

class Monad m => RefMonad m r | m -> r, r -> m where Source

Class of monads with references. Methods newRef :: a -> m (r a) Source readRef :: r a -> m a Source writeRef :: r a -> a -> m () Source Instances RefMonad IO IORef RefMonad IO IORef RefMonad (ST s) (STRef s) RefMonad (ST s) (STRef s)

modifyRef :: RefMonad m r => r a -> (a -> a) -> m () Source

Change the contents of a ref

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