Copyright	(c) Adam C. Foltzer 2013
License	BSD3
Maintainer	acfoltzer@gmail.com
Stability	experimental
Portability	non-portable (requires rank-2 types for runST)
Safe Haskell	None
Language	Haskell98

Data.STRef.Persistent

Contents

STRefs
MonadRef Operations
Orphan instances

Description

Mutable references in the persistent ST monad.

Synopsis

data STRef s a
asInt :: STRef s a -> Int
class Monad m => MonadRef (r :: * -> *) (m :: * -> *) | m -> r where

`STRef`s

data STRef s a #

Instances

Monad m => MonadRef (STRef s) (STT s m) #
Instance details Defined in Data.STRef.Persistent Methods newRef :: a -> STT s m (STRef s a) # readRef :: STRef s a -> STT s m a # writeRef :: STRef s a -> a -> STT s m () # modifyRef :: STRef s a -> (a -> a) -> STT s m () # modifyRef' :: STRef s a -> (a -> a) -> STT s m () #
Eq (STRef s a) #
Instance details Defined in Data.STRef.Persistent Methods (==) :: STRef s a -> STRef s a -> Bool # (/=) :: STRef s a -> STRef s a -> Bool #
Show (STRef s a) #
Instance details Defined in Data.STRef.Persistent Methods showsPrec :: Int -> STRef s a -> ShowS # show :: STRef s a -> String # showList :: [STRef s a] -> ShowS #

asInt :: STRef s a -> Int #

Get the underlying Int from an STRef. Useful for debugging.

`MonadRef` Operations

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
Instance details Defined in Control.Monad.Ref 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
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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)
Instance details Defined in Control.Monad.Ref 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 () #
Monad m => MonadRef (STRef s) (STT s m) #
Instance details Defined in Data.STRef.Persistent Methods newRef :: a -> STT s m (STRef s a) # readRef :: STRef s a -> STT s m a # writeRef :: STRef s a -> a -> STT s m () # modifyRef :: STRef s a -> (a -> a) -> STT s m () # modifyRef' :: STRef s a -> (a -> a) -> STT s m () #

Orphan instances

Monad m => MonadRef (STRef s) (STT s m) #
Instance details Methods newRef :: a -> STT s m (STRef s a) # readRef :: STRef s a -> STT s m a # writeRef :: STRef s a -> a -> STT s m () # modifyRef :: STRef s a -> (a -> a) -> STT s m () # modifyRef' :: STRef s a -> (a -> a) -> STT s m () #

STRefs

MonadRef Operations

Orphan instances

`STRef`s

`MonadRef` Operations