| Copyright | (c) Harvard University 2006-2011 (c) Geoffrey Mainland 2011-2014 |
|---|---|
| License | BSD-style |
| Maintainer | Geoffrey Mainland <mainland@cs.drexel.edu> |
| Stability | experimental |
| Portability | non-portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Control.Monad.Ref
Description
Synopsis
- class Monad m => MonadRef r m | m -> r where
- newRef :: a -> m (r a)
- readRef :: r a -> m a
- writeRef :: r a -> a -> m ()
- modifyRef :: r a -> (a -> a) -> m ()
- modifyRef' :: r a -> (a -> a) -> m ()
- class MonadRef r m => MonadAtomicRef r m | m -> r where
- atomicModifyRef :: r a -> (a -> (a, b)) -> m b
- atomicModifyRef' :: r a -> (a -> (a, b)) -> m b
Documentation
class Monad m => MonadRef r m | m -> r where Source #
The MonadRef type class abstracts over the details of manipulating
references, allowing one to write code that uses references and can operate
in any monad that supports reference operations.
Methods
newRef :: a -> m (r a) Source #
Create a new reference
readRef :: r a -> m a Source #
Read the value of a reference
writeRef :: r a -> a -> m () Source #
Write a new value to a reference
modifyRef :: r a -> (a -> a) -> m () Source #
Mutate the contents of a reference
modifyRef' :: r a -> (a -> a) -> m () Source #
Strict version of modifyRef
Instances
| MonadRef TVar STM Source # | |
| MonadRef IORef IO Source # | |
| MonadRef r m => MonadRef r (MaybeT m) Source # | |
| MonadRef r m => MonadRef r (ListT m) Source # | |
| (Monoid w, MonadRef r m) => MonadRef r (WriterT w m) Source # | |
| (Monoid w, MonadRef r m) => MonadRef r (WriterT w m) Source # | |
| MonadRef r m => MonadRef r (StateT s m) Source # | |
| MonadRef r m => MonadRef r (StateT s m) Source # | |
| MonadRef r m => MonadRef r (ReaderT r' m) Source # | |
| MonadRef r m => MonadRef r (IdentityT m) Source # | |
| MonadRef r m => MonadRef r (ExceptT e m) Source # | |
| (Error e, MonadRef r m) => MonadRef r (ErrorT e m) Source # | |
| MonadRef r m => MonadRef r (ContT r' m) Source # | |
| MonadRef (STRef s) (ST s) Source # | |
class MonadRef r m => MonadAtomicRef r m | m -> r where Source #
Minimal complete definition
Methods
atomicModifyRef :: r a -> (a -> (a, b)) -> m b Source #
Atomically mutate the contents of a reference
atomicModifyRef' :: r a -> (a -> (a, b)) -> m b Source #
Strict version of atomicModifyRef. This forces both the value stored in the reference as well as the value returned.