Data.StateRef.Types

Documentation

data Ref m a where

A simple reference type, hiding the complexity of all these type classes, since most of the time the only thing you care about is that you want a reference. The full complexity is still there, though, so FFI types or other reference-like things can still be made into Refs.

Constructors

Ref :: ModifyRef sr m a => !sr -> Ref m a

Instances

HasRef m => NewRef (Ref m a) m a

MonadIO m => NewRef (Ref STM a) m a

ModifyRef (Ref m a) m a

MonadIO m => ModifyRef (Ref STM a) m a

ReadRef (Ref m a) m a

MonadIO m => ReadRef (Ref STM a) m a

WriteRef (Ref m a) m a

MonadIO m => WriteRef (Ref STM a) m a

class WriteRef sr m a | sr -> a where

Methods

writeReference :: sr -> a -> m ()

Replace the existing value of the given reference with the provided value.

Instances

(Storable a, MonadIO m) => WriteRef (ForeignPtr a) m a

MonadIO m => WriteRef (TVar a) m a

WriteRef (TVar a) STM a

MonadIO m => WriteRef (IORef a) m a

WriteRef sr m a => WriteRef (UnsafeModifyRef sr) m a

WriteRef (STRef RealWorld a) IO a

WriteRef (Ref m a) m a

MonadIO m => WriteRef (Ref STM a) m a

Monad m => WriteRef (Accessor m a) m a

Monad m => WriteRef (Setter m a) m a

WriteRef (STRef s a) (ST s) a

WriteRef (STRef s a) (ST s) a

class ReadRef sr m a | sr -> a where

Methods

readReference :: sr -> m a

Get the current value referenced by the given state reference.

Instances

MonadIO m => ReadRef (IO a) m a

(Storable a, MonadIO m) => ReadRef (ForeignPtr a) m a

MonadIO m => ReadRef (STM a) m a

ReadRef (STM a) STM a

MonadIO m => ReadRef (TVar a) m a

ReadRef (TVar a) STM a

MonadIO m => ReadRef (IORef a) m a

ReadRef sr m a => ReadRef (UnsafeModifyRef sr) m a

MonadIO m => ReadRef (TMVar a) m (Maybe a)

ReadRef (TMVar a) STM (Maybe a)

MonadIO m => ReadRef (ST RealWorld a) m a

ReadRef (STRef RealWorld a) IO a

ReadRef (Ref m a) m a

MonadIO m => ReadRef (Ref STM a) m a

Monad m => ReadRef (Accessor m a) m a

Monad m => ReadRef (Getter m a) m a

ReadRef (ST s a) (ST s) a

ReadRef (STRef s a) (ST s) a

ReadRef (STRef s a) (ST s) a

class (ReadRef sr m a, WriteRef sr m a) => ModifyRef sr m a | sr -> a where

Methods

atomicModifyReference :: sr -> (a -> (a, b)) -> m b

Atomically modify the contents of a reference. This is implemented in a separate class (rather than a function with context (ReadRef sr m a, WriteRef sr m a)) because in most cases the default implementation cannot act atomically.

modifyReference :: sr -> (a -> a) -> m ()

Same thing, but don't thread out the extra return. Could perhaps be implemented slightly more efficiently than atomicModifyReference in many cases. Note that implementations are expected to be atomic, if at all possible, but not strictly required to be.

Instances

(Storable a, MonadIO m) => ModifyRef (ForeignPtr a) m a

MonadIO m => ModifyRef (TVar a) m a

ModifyRef (TVar a) STM a

MonadIO m => ModifyRef (IORef a) m a

(Monad m, ReadRef sr m a, WriteRef sr m a) => ModifyRef (UnsafeModifyRef sr) m a

ModifyRef (STRef RealWorld a) IO a

ModifyRef (Ref m a) m a

MonadIO m => ModifyRef (Ref STM a) m a

ModifyRef (STRef s a) (ST s) a

ModifyRef (STRef s a) (ST s) a

defaultAtomicModifyReference :: (Monad m, ReadRef sr m t, WriteRef sr m a) => sr -> (t -> (a, b)) -> m b

Default implementation of atomicModifyReference in terms of readReference and writeReference

defaultModifyReference :: (Monad m, ReadRef sr m t, WriteRef sr m a) => sr -> (t -> a) -> m ()

Default implementation of modifyReference in terms of readReference and writeReference

class NewRef sr m a | sr -> a where

Methods

newReference :: a -> m sr

Construct a new reference to the provided value.

Instances

Monad m => NewRef (IO a) m a

(Storable a, MonadIO m) => NewRef (ForeignPtr a) m a

MonadIO m => NewRef (TVar a) m a

NewRef (TVar a) STM a

MonadIO m => NewRef (IORef a) m a

MonadIO m => NewRef (MVar a) m (Maybe a)

MonadIO m => NewRef (TMVar a) m (Maybe a)

NewRef (TMVar a) STM (Maybe a)

Monad m => NewRef (ST s a) m a

NewRef (STRef RealWorld a) IO a

HasRef m => NewRef (Ref m a) m a

MonadIO m => NewRef (Ref STM a) m a

NewRef (STRef s a) (ST s) a

NewRef (STRef s a) (ST s) a

class HasRef m where

Methods

newRef :: a -> m (Ref m a)

Construct a new mutable reference (of an unspecified implementation type) containing the provided value.

Instances

HasRef IO

HasRef STM

HasRef (ST s)

HasRef (ST s)