Safe Haskell	None
Language	GHC2021

Effects.Concurrent.STM

Contents

Effect
TVar
- Strict
  - Atomic
- Lazy
  - Atomic
TBQueue
- Strict
  - Atomic
- Lazy
  - Atomic
Reexports

Description

Provides classes for STM.

Since: 0.1

Synopsis

data STM a
class Monad m => MonadAtomic (m :: Type -> Type) where
- atomically :: HasCallStack => STM a -> m a
data TVar a
newTVar' :: a -> STM (TVar a)
readTVar' :: TVar a -> STM a
writeTVar' :: TVar a -> a -> STM ()
modifyTVar' :: TVar a -> (a -> a) -> STM ()
newTVarA' :: (HasCallStack, MonadAtomic m) => a -> m (TVar a)
readTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> m a
writeTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> a -> m ()
modifyTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> (a -> a) -> m ()
newTVar :: a -> STM (TVar a)
readTVar :: TVar a -> STM a
writeTVar :: TVar a -> a -> STM ()
modifyTVar :: TVar a -> (a -> a) -> STM ()
newTVarA :: (HasCallStack, MonadAtomic m) => a -> m (TVar a)
readTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> m a
writeTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> a -> m ()
modifyTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> (a -> a) -> m ()
data TBQueue a
readTBQueue' :: TBQueue a -> STM a
tryReadTBQueue' :: TBQueue a -> STM (Maybe a)
writeTBQueue' :: TBQueue a -> a -> STM ()
flushTBQueue' :: TBQueue a -> STM [a]
readTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m a
tryReadTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m (Maybe a)
writeTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> a -> m ()
flushTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m [a]
newTBQueue :: Natural -> STM (TBQueue a)
readTBQueue :: TBQueue a -> STM a
tryReadTBQueue :: TBQueue a -> STM (Maybe a)
writeTBQueue :: TBQueue a -> a -> STM ()
flushTBQueue :: TBQueue a -> STM [a]
newTBQueueA :: (HasCallStack, MonadAtomic m) => Natural -> m (TBQueue a)
readTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m a
tryReadTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m (Maybe a)
writeTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> a -> m ()
flushTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m [a]
data Natural

Effect

data STM a #

A monad supporting atomic memory transactions.

Instances

Instances details

Alternative STM #	Takes the first non-`retry`ing `STM` action. Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods empty :: STM a # (<\|>) :: STM a -> STM a -> STM a # some :: STM a -> STM [a] # many :: STM a -> STM [a] #
Applicative STM #	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods pure :: a -> STM a # (<>) :: STM (a -> b) -> STM a -> STM b # liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c # (>) :: STM a -> STM b -> STM b # (<*) :: STM a -> STM b -> STM a #
Functor STM #	Since: base-4.3.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods fmap :: (a -> b) -> STM a -> STM b # (<$) :: a -> STM b -> STM a #
Monad STM #	Since: base-4.3.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods (>>=) :: STM a -> (a -> STM b) -> STM b # (>>) :: STM a -> STM b -> STM b # return :: a -> STM a #
MonadPlus STM #	Takes the first non-`retry`ing `STM` action. Since: base-4.3.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods mzero :: STM a # mplus :: STM a -> STM a -> STM a #
MArray TArray e STM #
Instance details Defined in Control.Concurrent.STM.TArray Methods getBounds :: Ix i => TArray i e -> STM (i, i) # getNumElements :: Ix i => TArray i e -> STM Int # newArray :: Ix i => (i, i) -> e -> STM (TArray i e) # newArray_ :: Ix i => (i, i) -> STM (TArray i e) # unsafeNewArray_ :: Ix i => (i, i) -> STM (TArray i e) # unsafeRead :: Ix i => TArray i e -> Int -> STM e # unsafeWrite :: Ix i => TArray i e -> Int -> e -> STM () #
Monoid a => Monoid (STM a) #	Since: base-4.17.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods mempty :: STM a # mappend :: STM a -> STM a -> STM a # mconcat :: [STM a] -> STM a #
Semigroup a => Semigroup (STM a) #	Since: base-4.17.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods (<>) :: STM a -> STM a -> STM a # sconcat :: NonEmpty (STM a) -> STM a # stimes :: Integral b => b -> STM a -> STM a #

class Monad m => MonadAtomic (m :: Type -> Type) where Source #

Effect for atomically lifting STM actions. Note that this classes is intended for "IO-like" monads not "STM-like" monads -- hence has no STM instance -- as the semantics for "STM-like" and "can lift STM atomically" are different.

Since: 0.1

Methods

atomically :: HasCallStack => STM a -> m a Source #

Lifted atomically.

Since: 0.1

Instances

Instances details

MonadAtomic IO Source #	Since: 0.1
Instance details Defined in Effects.Concurrent.STM Methods atomically :: HasCallStack => STM a -> IO a Source #
MonadAtomic m => MonadAtomic (ReaderT e m) Source #	Since: 0.1
Instance details Defined in Effects.Concurrent.STM Methods atomically :: HasCallStack => STM a -> ReaderT e m a Source #

TVar

data TVar a #

Shared memory locations that support atomic memory transactions.

Instances

Instances details

Eq (TVar a) #	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods (==) :: TVar a -> TVar a -> Bool # (/=) :: TVar a -> TVar a -> Bool #

Strict

newTVar' :: a -> STM (TVar a) Source #

Evaluates the input to newTVar to WHNF.

Since: 0.1

readTVar' :: TVar a -> STM a Source #

Evaluates the output from readTVar to WHNF.

Since: 0.1

writeTVar' :: TVar a -> a -> STM () Source #

Evaluates the input to writeTVar to WHNF.

Since: 0.1

modifyTVar' :: TVar a -> (a -> a) -> STM () #

Strict version of modifyTVar.

Since: stm-2.3

Atomic

newTVarA' :: (HasCallStack, MonadAtomic m) => a -> m (TVar a) Source #

Atomic newTVar'.

Since: 0.1

readTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> m a Source #

Atomic readTVarA'.

Since: 0.1

writeTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> a -> m () Source #

Atomic writeTVarA'.

Since: 0.1

modifyTVarA' :: (HasCallStack, MonadAtomic m) => TVar a -> (a -> a) -> m () Source #

Atomic modifyTVar'.

Since: 0.1

Lazy

newTVar :: a -> STM (TVar a) #

Create a new TVar holding a value supplied

readTVar :: TVar a -> STM a #

Return the current value stored in a TVar.

writeTVar :: TVar a -> a -> STM () #

Write the supplied value into a TVar.

modifyTVar :: TVar a -> (a -> a) -> STM () #

Mutate the contents of a TVar. N.B., this version is non-strict.

Since: stm-2.3

Atomic

newTVarA :: (HasCallStack, MonadAtomic m) => a -> m (TVar a) Source #

Create a new TVar holding a value supplied and lifts the result via atomically.

Since: 0.1

readTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> m a Source #

Return the current value stored in a TVar and lifts the result via atomically.

Since: 0.1

writeTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> a -> m () Source #

Write the supplied value into a TVar and lifts the action via atomically.

Since: 0.1

modifyTVarA :: (HasCallStack, MonadAtomic m) => TVar a -> (a -> a) -> m () Source #

Atomic modifyTVar.

Since: 0.1

TBQueue

data TBQueue a #

TBQueue is an abstract type representing a bounded FIFO channel.

Since: stm-2.4

Instances

Instances details

Eq (TBQueue a) #
Instance details Defined in Control.Concurrent.STM.TBQueue Methods (==) :: TBQueue a -> TBQueue a -> Bool # (/=) :: TBQueue a -> TBQueue a -> Bool #

Strict

readTBQueue' :: TBQueue a -> STM a Source #

Evaluates the output from readTBQueue to WHNF.

Since: 0.1

tryReadTBQueue' :: TBQueue a -> STM (Maybe a) Source #

Evaluates the output from tryReadTBQueue to Nothing or Just a, where a is in WHNF.

Since: 0.1

writeTBQueue' :: TBQueue a -> a -> STM () Source #

Evaluates the input to writeTBQueue to WHNF.

Since: 0.1

flushTBQueue' :: TBQueue a -> STM [a] Source #

Evaluates the output from flushTBQueue to WHNF.

Since: 0.1

Atomic

readTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m a Source #

Atomic readTBQueue'.

Since: 0.1

tryReadTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m (Maybe a) Source #

Atomic tryReadTBQueue'.

Since: 0.1

writeTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> a -> m () Source #

Atomic writeTBQueue'.

Since: 0.1

flushTBQueueA' :: (HasCallStack, MonadAtomic m) => TBQueue a -> m [a] Source #

Atomic flushTBQueue'.

Since: 0.1

Lazy

newTBQueue #

Arguments

:: Natural	maximum number of elements the queue can hold
-> STM (TBQueue a)

Builds and returns a new instance of TBQueue.

readTBQueue :: TBQueue a -> STM a #

Read the next value from the TBQueue.

tryReadTBQueue :: TBQueue a -> STM (Maybe a) #

A version of readTBQueue which does not retry. Instead it returns Nothing if no value is available.

writeTBQueue :: TBQueue a -> a -> STM () #

Write a value to a TBQueue; blocks if the queue is full.

flushTBQueue :: TBQueue a -> STM [a] #

Efficiently read the entire contents of a TBQueue into a list. This function never retries.

Since: stm-2.4.5

Atomic

newTBQueueA Source #

Arguments

:: (HasCallStack, MonadAtomic m)
=> Natural	maximum number of elements the queue can hold
-> m (TBQueue a)

Builds and returns a new instance of TBQueue, lifting via atomically.

Since: 0.1

readTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m a Source #

Read the next value from the TBQueue, lifting via atomically.

Since: 0.1

tryReadTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m (Maybe a) Source #

A version of readTBQueue which does not retry. Instead it returns Nothing if no value is available. Lifts via atomically.

Since: 0.1

writeTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> a -> m () Source #

Write a value to a TBQueue; blocks if the queue is full. Lifts via atomically.

Since: 0.1

flushTBQueueA :: (HasCallStack, MonadAtomic m) => TBQueue a -> m [a] Source #

Efficiently read the entire contents of a TBQueue into a list. This function never retries. Lifts via atomically.

Since: 0.1

Reexports

data Natural #

Natural number

Invariant: numbers <= 0xffffffffffffffff use the NS constructor

Instances

Instances details

PrintfArg Natural #	Since: base-4.8.0.0
Instance details Defined in Text.Printf Methods formatArg :: Natural -> FieldFormatter # parseFormat :: Natural -> ModifierParser #
Num Natural #	Note that `Natural`'s `Num` instance isn't a ring: no element but 0 has an additive inverse. It is a semiring though. Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Num Methods (+) :: Natural -> Natural -> Natural # (-) :: Natural -> Natural -> Natural # (*) :: Natural -> Natural -> Natural # negate :: Natural -> Natural # abs :: Natural -> Natural # signum :: Natural -> Natural # fromInteger :: Integer -> Natural #
Eq Natural #
Instance details Defined in GHC.Num.Natural Methods (==) :: Natural -> Natural -> Bool # (/=) :: Natural -> Natural -> Bool #
Ord Natural #
Instance details Defined in GHC.Num.Natural Methods compare :: Natural -> Natural -> Ordering # (<) :: Natural -> Natural -> Bool # (<=) :: Natural -> Natural -> Bool # (>) :: Natural -> Natural -> Bool # (>=) :: Natural -> Natural -> Bool # max :: Natural -> Natural -> Natural # min :: Natural -> Natural -> Natural #
KnownNat n => HasResolution (n :: Nat) #	For example, `Fixed 1000` will give you a `Fixed` with a resolution of 1000.
Instance details Defined in Data.Fixed Methods resolution :: p n -> Integer #