IOSpec-0.1.1: A pure specification of the IO monad. Source code Contents Index

Test.IOSpec.Concurrent

Contents The IOConc monad Supported functions Schedulers

Description

A pure specification of basic concurrency operations.

Synopsis

data IOConc a runIOConc :: IOConc a -> Scheduler -> Maybe a data ThreadId data MVar a newEmptyMVar :: IOConc (MVar a) takeMVar :: Typeable a => MVar a -> IOConc a putMVar :: Typeable a => MVar a -> a -> IOConc () forkIO :: IOConc a -> IOConc ThreadId newtype Scheduler = Scheduler (Int -> (ThreadId, Scheduler)) streamSched :: Stream Int -> Scheduler roundRobin :: Scheduler

The IOConc monad

data IOConc a Source

Instances Monad IOConc Functor IOConc

runIOConc :: IOConc a -> Scheduler -> Maybe a Source

The runIOConc function runs a concurrent computation with a given scheduler. If a deadlock occurs, Nothing is returned.

Supported functions

data ThreadId Source

Instances Eq ThreadId Show ThreadId

data MVar a Source

An MVar is a shared, mutable variable. Instances Typeable1 MVar

newEmptyMVar :: IOConc (MVar a) Source

The newEmptyMVar function creates a new MVar that is initially empty.

takeMVar :: Typeable a => MVar a -> IOConc a Source

The takeMVar function removes the value stored in an MVar. If the MVar is empty, the thread is blocked.

putMVar :: Typeable a => MVar a -> a -> IOConc () Source

The putMVar function fills an MVar with a new value. If the MVar is not empty, the thread is blocked.

forkIO :: IOConc a -> IOConc ThreadId Source

The forkIO function forks off a new thread.

Schedulers

newtype Scheduler Source

A scheduler consists of a function that, given the number of threads, returns the ThreadId of the next scheduled thread, together with a new scheduler. Constructors Scheduler (Int -> (ThreadId, Scheduler))

streamSched :: Stream Int -> Scheduler Source

Given a stream of integers, streamSched builds a scheduler. This is especially useful if you use QuickCheck and generate a random stream; the resulting random scheduler will hopefully cover a large number of interleavings.

roundRobin :: Scheduler Source

A simple round-robin scheduler.

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