Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Concurrent.Class.MonadSTM.TVar

Contents

MonadSTM
MonadLabelSTM
MonadTraceSTM

Description

This module corresponds to TVar in "stm" package

Synopsis

type family TVar m :: Type -> Type
newTVar :: MonadSTM m => a -> STM m (TVar m a)
newTVarIO :: MonadSTM m => a -> m (TVar m a)
readTVar :: MonadSTM m => TVar m a -> STM m a
readTVarIO :: MonadSTM m => TVar m a -> m a
writeTVar :: MonadSTM m => TVar m a -> a -> STM m ()
modifyTVar :: MonadSTM m => TVar m a -> (a -> a) -> STM m ()
modifyTVar' :: MonadSTM m => TVar m a -> (a -> a) -> STM m ()
stateTVar :: MonadSTM m => TVar m s -> (s -> (a, s)) -> STM m a
swapTVar :: MonadSTM m => TVar m a -> a -> STM m a
check :: MonadSTM m => Bool -> STM m ()
labelTVar :: MonadLabelledSTM m => TVar m a -> String -> STM m ()
labelTVarIO :: MonadLabelledSTM m => TVar m a -> String -> m ()
traceTVar :: MonadTraceSTM m => proxy m -> TVar m a -> (Maybe a -> a -> InspectMonad m TraceValue) -> STM m ()
traceTVarIO :: MonadTraceSTM m => TVar m a -> (Maybe a -> a -> InspectMonad m TraceValue) -> m ()

MonadSTM

type family TVar m :: Type -> Type Source #

A type of a TVar.

See TVar.

Instances

Instances details

type TVar IO Source #
Instance details Defined in Control.Monad.Class.MonadSTM.Internal type TVar IO = TVar
type TVar (ReaderT r m) Source #
Instance details Defined in Control.Monad.Class.MonadSTM.Internal type TVar (ReaderT r m) = TVar m

newTVar :: MonadSTM m => a -> STM m (TVar m a) Source #

newTVarIO :: MonadSTM m => a -> m (TVar m a) Source #

readTVar :: MonadSTM m => TVar m a -> STM m a Source #

readTVarIO :: MonadSTM m => TVar m a -> m a Source #

writeTVar :: MonadSTM m => TVar m a -> a -> STM m () Source #

modifyTVar :: MonadSTM m => TVar m a -> (a -> a) -> STM m () Source #

modifyTVar' :: MonadSTM m => TVar m a -> (a -> a) -> STM m () Source #

stateTVar :: MonadSTM m => TVar m s -> (s -> (a, s)) -> STM m a Source #

@since io-classes-0.2.0.0

swapTVar :: MonadSTM m => TVar m a -> a -> STM m a Source #

check :: MonadSTM m => Bool -> STM m () Source #

See check.

MonadLabelSTM

labelTVar :: MonadLabelledSTM m => TVar m a -> String -> STM m () Source #

Name a TVar.

labelTVarIO :: MonadLabelledSTM m => TVar m a -> String -> m () Source #

MonadTraceSTM

traceTVar Source #

Arguments

:: MonadTraceSTM m
=> proxy m
-> TVar m a
-> (Maybe a -> a -> InspectMonad m TraceValue)	callback which receives initial value or `Nothing` (if it is a newly created `TVar`), and the committed value.
-> STM m ()

Construct a trace output out of previous & new value of a TVar. The callback is called whenever an stm transaction which modifies the TVar is committed.

This is supported by IOSim (and IOSimPOR); IO has a trivial instance.

The simplest example is:

traceTVar (Proxy @m) tvar (\_ -> TraceString . show)

Note that the interpretation of TraceValue depends on the monad m itself (see TraceValue).

traceTVarIO :: MonadTraceSTM m => TVar m a -> (Maybe a -> a -> InspectMonad m TraceValue) -> m () Source #