monad-par-0.3.4: A library for parallel programming based on a monad

Safe HaskellNone



This module exposes the internals of the Par monad so that you can build your own scheduler or other extensions. Do not use this module for purposes other than extending the Par monad with new functionality.



data Trace Source


forall a . Get (IVar a) (a -> Trace) 
forall a . Put (IVar a) a Trace 
forall a . New (IVarContents a) (IVar a -> Trace) 
Fork Trace Trace 
Yield Trace 

data Sched Source




no :: !Int
workpool :: IORef [Trace]
idle :: IORef [MVar Bool]
scheds :: [Sched]

newtype Par a Source




runCont :: (a -> Trace) -> Trace

newtype IVar a Source


IVar (IORef (IVarContents a)) 

data IVarContents a Source


Full a 
Blocked [a -> Trace] 

sched :: Bool -> Sched -> Trace -> IO ()Source

The main scheduler loop.

runPar :: Par a -> aSource

runParIO :: Par a -> IO aSource

A version that avoids an internal unsafePerformIO for calling contexts that are already in the IO monad.

runParAsync :: Par a -> aSource

An asynchronous version in which the main thread of control in a Par computation can return while forked computations still run in the background.

new :: Par (IVar a)Source

creates a new IVar

newFull :: NFData a => a -> Par (IVar a)Source

creates a new IVar that contains a value

newFull_ :: a -> Par (IVar a)Source

creates a new IVar that contains a value (head-strict only)

get :: IVar a -> Par aSource

read the value in a IVar. The get can only return when the value has been written by a prior or parallel put to the same IVar.

put_ :: IVar a -> a -> Par ()Source

like put, but only head-strict rather than fully-strict.

put :: NFData a => IVar a -> a -> Par ()Source

put a value into a IVar. Multiple puts to the same IVar are not allowed, and result in a runtime error.

put fully evaluates its argument, which therefore must be an instance of NFData. The idea is that this forces the work to happen when we expect it, rather than being passed to the consumer of the IVar and performed later, which often results in less parallelism than expected.

Sometimes partial strictness is more appropriate: see put_.

yield :: Par ()Source

Allows other parallel computations to progress. (should not be necessary in most cases).