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
Language	Haskell98

Control.Monad.Ref

Description

Synopsis

Documentation

class Monad m => MonadRef r m | m -> r where #

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.

Minimal complete definition

newRef, readRef, writeRef

Methods

newRef :: a -> m (r a) #

Create a new reference

readRef :: r a -> m a #

Read the value of a reference

writeRef :: r a -> a -> m () #

Write a new value to a reference

modifyRef :: r a -> (a -> a) -> m () #

Mutate the contents of a reference

modifyRef' :: r a -> (a -> a) -> m () #

Strict version of modifyRef

Instances

MonadRef TVar STM #
Methods newRef :: a -> STM (TVar a) # readRef :: TVar a -> STM a # writeRef :: TVar a -> a -> STM () # modifyRef :: TVar a -> (a -> a) -> STM () # modifyRef' :: TVar a -> (a -> a) -> STM () #
MonadRef IORef IO #
Methods newRef :: a -> IO (IORef a) # readRef :: IORef a -> IO a # writeRef :: IORef a -> a -> IO () # modifyRef :: IORef a -> (a -> a) -> IO () # modifyRef' :: IORef a -> (a -> a) -> IO () #
MonadRef r m => MonadRef r (MaybeT m) #
Methods newRef :: a -> MaybeT m (r a) # readRef :: r a -> MaybeT m a # writeRef :: r a -> a -> MaybeT m () # modifyRef :: r a -> (a -> a) -> MaybeT m () # modifyRef' :: r a -> (a -> a) -> MaybeT m () #
MonadRef r m => MonadRef r (ListT m) #
Methods newRef :: a -> ListT m (r a) # readRef :: r a -> ListT m a # writeRef :: r a -> a -> ListT m () # modifyRef :: r a -> (a -> a) -> ListT m () # modifyRef' :: r a -> (a -> a) -> ListT m () #
(Monoid w, MonadRef r m) => MonadRef r (WriterT w m) #
Methods newRef :: a -> WriterT w m (r a) # readRef :: r a -> WriterT w m a # writeRef :: r a -> a -> WriterT w m () # modifyRef :: r a -> (a -> a) -> WriterT w m () # modifyRef' :: r a -> (a -> a) -> WriterT w m () #
(Monoid w, MonadRef r m) => MonadRef r (WriterT w m) #
Methods newRef :: a -> WriterT w m (r a) # readRef :: r a -> WriterT w m a # writeRef :: r a -> a -> WriterT w m () # modifyRef :: r a -> (a -> a) -> WriterT w m () # modifyRef' :: r a -> (a -> a) -> WriterT w m () #
MonadRef r m => MonadRef r (StateT s m) #
Methods newRef :: a -> StateT s m (r a) # readRef :: r a -> StateT s m a # writeRef :: r a -> a -> StateT s m () # modifyRef :: r a -> (a -> a) -> StateT s m () # modifyRef' :: r a -> (a -> a) -> StateT s m () #
MonadRef r m => MonadRef r (StateT s m) #
Methods newRef :: a -> StateT s m (r a) # readRef :: r a -> StateT s m a # writeRef :: r a -> a -> StateT s m () # modifyRef :: r a -> (a -> a) -> StateT s m () # modifyRef' :: r a -> (a -> a) -> StateT s m () #
MonadRef r m => MonadRef r (IdentityT * m) #
Methods newRef :: a -> IdentityT * m (r a) # readRef :: r a -> IdentityT * m a # writeRef :: r a -> a -> IdentityT * m () # modifyRef :: r a -> (a -> a) -> IdentityT * m () # modifyRef' :: r a -> (a -> a) -> IdentityT * m () #
MonadRef r m => MonadRef r (ExceptT e m) #
Methods newRef :: a -> ExceptT e m (r a) # readRef :: r a -> ExceptT e m a # writeRef :: r a -> a -> ExceptT e m () # modifyRef :: r a -> (a -> a) -> ExceptT e m () # modifyRef' :: r a -> (a -> a) -> ExceptT e m () #
(Error e, MonadRef r m) => MonadRef r (ErrorT e m) #
Methods newRef :: a -> ErrorT e m (r a) # readRef :: r a -> ErrorT e m a # writeRef :: r a -> a -> ErrorT e m () # modifyRef :: r a -> (a -> a) -> ErrorT e m () # modifyRef' :: r a -> (a -> a) -> ErrorT e m () #
MonadRef r m => MonadRef r (ReaderT * r' m) #
Methods newRef :: a -> ReaderT * r' m (r a) # readRef :: r a -> ReaderT * r' m a # writeRef :: r a -> a -> ReaderT * r' m () # modifyRef :: r a -> (a -> a) -> ReaderT * r' m () # modifyRef' :: r a -> (a -> a) -> ReaderT * r' m () #
MonadRef r m => MonadRef r (ContT * r' m) #
Methods newRef :: a -> ContT * r' m (r a) # readRef :: r a -> ContT * r' m a # writeRef :: r a -> a -> ContT * r' m () # modifyRef :: r a -> (a -> a) -> ContT * r' m () # modifyRef' :: r a -> (a -> a) -> ContT * r' m () #
MonadRef (STRef s) (ST s) #
Methods newRef :: a -> ST s (STRef s a) # readRef :: STRef s a -> ST s a # writeRef :: STRef s a -> a -> ST s () # modifyRef :: STRef s a -> (a -> a) -> ST s () # modifyRef' :: STRef s a -> (a -> a) -> ST s () #

class MonadRef r m => MonadAtomicRef r m | m -> r where #

Minimal complete definition

atomicModifyRef

Methods

atomicModifyRef :: r a -> (a -> (a, b)) -> m b #

Atomically mutate the contents of a reference

atomicModifyRef' :: r a -> (a -> (a, b)) -> m b #

Strict version of atomicModifyRef. This forces both the value stored in the reference as well as the value returned.

Instances

MonadAtomicRef TVar STM #
Methods atomicModifyRef :: TVar a -> (a -> (a, b)) -> STM b # atomicModifyRef' :: TVar a -> (a -> (a, b)) -> STM b #
MonadAtomicRef IORef IO #
Methods atomicModifyRef :: IORef a -> (a -> (a, b)) -> IO b # atomicModifyRef' :: IORef a -> (a -> (a, b)) -> IO b #
MonadAtomicRef r m => MonadAtomicRef r (MaybeT m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> MaybeT m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> MaybeT m b #
MonadAtomicRef r m => MonadAtomicRef r (ListT m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> ListT m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> ListT m b #
(Monoid w, MonadAtomicRef r m) => MonadAtomicRef r (WriterT w m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> WriterT w m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> WriterT w m b #
(Monoid w, MonadAtomicRef r m) => MonadAtomicRef r (WriterT w m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> WriterT w m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> WriterT w m b #
MonadAtomicRef r m => MonadAtomicRef r (StateT s m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> StateT s m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> StateT s m b #
MonadAtomicRef r m => MonadAtomicRef r (StateT s m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> StateT s m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> StateT s m b #
MonadAtomicRef r m => MonadAtomicRef r (IdentityT * m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> IdentityT * m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> IdentityT * m b #
(Error e, MonadAtomicRef r m) => MonadAtomicRef r (ErrorT e m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> ErrorT e m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> ErrorT e m b #
MonadAtomicRef r m => MonadAtomicRef r (ReaderT * r' m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> ReaderT * r' m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> ReaderT * r' m b #
MonadAtomicRef r m => MonadAtomicRef r (ContT * r' m) #
Methods atomicModifyRef :: r a -> (a -> (a, b)) -> ContT * r' m b # atomicModifyRef' :: r a -> (a -> (a, b)) -> ContT * r' m b #