Module Control.concurrent.STM

• Software Transactional Memory (STM)
• This STM implements an optimistic concurrency control for Frege.
• It is based on
• Harris, Tim, Simon Marlow, Simon Peyton-Jones, and Maurice Herlihy (2005).
• “Composable Memory Transactions”. In: Proceedings of the Tenth ACM SIG-
• PLAN Symposium on Principles and Practice of Parallel Programming. PPoPP
• ’05. 551050. Chicago, IL, USA: ACM, pp. 48–60. isbn: 1-59593-080-9.
• doi: http://dx.doi.org/10.2200/S00272ED1V01Y201006CAC011. url:
• http://doi.acm.org/10.1145/1065944.1065952
• An STM action is called transaction.

Imports

• import frege.Prelude as Prelude
• import Prelude.PreludeArrays as PreludeArrays
• import Prelude.PreludeBase as PreludeBase
• import Prelude.PreludeDecimal as PreludeDecimal
• import Prelude.PreludeIO as PreludeIO
• import Prelude.PreludeList as PreludeList
• import Prelude.PreludeMonad as PreludeMonad
• import Prelude.PreludeText as PreludeText
• import Java.util.Regex as Regexp

Table of Content

• Definitions

  type TMVar α = TVar (Maybe α)

  data STM α

  data STMResult α

  data STMWorld = pure native frege.runtime.Phantom.STM

  data TVar α

  newTVar ∷ α → STM (TVar α)

  readTVar ∷ TVar α → STM α

  writeTVar ∷ TVar α → α → STM ()

  retry ∷ STM α

  check ∷ Bool → STM ()

  atomically ∷ STM α → IO α

  newEmptyTMVar ∷ STM (TMVar α)

  newTMVar ∷ α → STM (TMVar α)

  takeTMVar ∷ TMVar α → STM α

  putTMVar ∷ TMVar α → α → STM ()

  pollTMVar ∷ TMVar α → STM (Maybe α)

• Instances

  instance MonadOr STM

  instance MonadPlus STM

  instance MonadZero STM

  instance Monad STM

• Functions and Values by Type

Definitions

data STMWorld = pure native frege.runtime.Phantom.STM

data STMResult α

Constructors

Result α

Retry

data STM α

Constructors

STM (ST STMWorld (STMResult α))

data TVar α

Container for shared mutable data.

Constructors

private TVar (Mutable STMWorld (NativeTVar α))

Member Functions

new ∷ α → STM (TVar α)

read ∷ TVar α → STM α

write ∷ TVar α → α → STM ()

newTVar ∷ α → STM (TVar α)

Alias for TVar.new

readTVar ∷ TVar α → STM α

Alias for TVar.read

writeTVar ∷ TVar α → α → STM ()

Alias for TVar.write

retry ∷ STM α

check ∷ Bool → STM ()

atomically ∷ STM α → IO α

Executes an STM action.

type TMVar α = TVar (Maybe α)

TMVars are MVars implemented using STM

newEmptyTMVar ∷ STM (TMVar α)

newTMVar ∷ α → STM (TMVar α)

takeTMVar ∷ TMVar α → STM α

putTMVar ∷ TMVar α → α → STM ()

pollTMVar ∷ TMVar α → STM (Maybe α)

Instances

instance MonadOr STM

Member Functions

orElse ∷ STM α → STM α → STM α

instance MonadPlus STM

Member Functions

mplus ∷ STM α → STM α → STM α
infixr  13

instance MonadZero STM

Member Functions

mzero ∷ STM α

instance Monad STM

Member Functions

*> ∷ STM α → STM β → STM β
infixl  4

inherited from Applicative.*>

<* ∷ STM α → STM β → STM α
infixl  4

inherited from Applicative.<*

<*> ∷ STM (α→β) → STM α → STM β
infixl  4

inherited from Monad.<*>

>> ∷ STM α → STM β → STM β
infixl  3

inherited from Monad.>>

>>= ∷ STM α → (α → STM β) → STM β
infixl  3

fmap ∷ (α → β) → STM α → STM β
infixl  4

inherited from Monad.fmap

join ∷ STM (STM α) → STM α

inherited from Monad.join

pure ∷ α → STM α

Functions and Values by Type

Bool → STM ()

check

ST STMWorld (STMResult α) → STM α

STM.STM

Mutable STMWorld (NativeTVar α) → TVar α

TVar.TVar

STM (STM α) → STM α

Monad_STM.join

STM α → STM α → STM α

MonadOr_STM.orElse, MonadPlus_STM.mplus

STM α → IO α

atomically

TMVar α → α → STM ()

putTMVar

TMVar α → STM (Maybe α)

pollTMVar

TMVar α → STM α

takeTMVar

TVar α → α → STM ()

TVar.write

TVar α → STM α

TVar.read

α → STM (TMVar α)

newTMVar

α → STM (TVar α)

TVar.new

α → STM α

Monad_STM.pure

α → STMResult α

STMResult.Result

STM (TMVar α)

newEmptyTMVar

STM α

retry, MonadZero_STM.mzero

STMResult α

STMResult.Retry

(α → β) → STM α → STM β

Monad_STM.fmap

STM (α→β) → STM α → STM β

Monad_STM.<*>

STM α → (α → STM β) → STM β

Monad_STM.>>=

STM α → STM β → STM α

Monad_STM.<*

STM α → STM β → STM β

Monad_STM.*>, Monad_STM.>>