Control.Concurrent.CHP.Enroll

A module with support for things that are enrollable (barriers and broadcast channels).

Documentation

data Enrolled b a

An enrolled wrapper for barriers that shows at the type-level whether you are enrolled on a barrier. Enrolled Barriers should never be passed to two (or more) processes running in parallel; if two processes synchronise based on a single enroll call, undefined behaviour will result.

Instances

ReadableChannel (Enrolled BroadcastChanin)

(Enum phase, Bounded phase, Eq phase) => Poisonable (Enrolled PhasedBarrier phase)

Poisonable (Enrolled BroadcastChanin a)

class Enrollable b z where

Methods

enroll :: b z -> (Enrolled b z -> CHP a) -> CHP a

Enrolls on the given barrier, then executes the given function (passing it in the enrolled barrier) and when that function body finishes, resigns from the barrier and returns the result. If a poison or IO exception is thrown in the inside block, the barrier will be correctly resigned from, and the exception rethrown.

Do not attempt to return the enrolled barrier out of the inner function and use it afterwards.

resign :: Enrolled b z -> CHP a -> CHP a

Resigns from a barrier, then executes the given action, and when the action finishes, re-enrolls on the barrier and continues. This function is designed for use from inside the body of the enroll function, to temporarily resign from a barrier, do some things, then re-enroll. Do not use the enrolled barrier inside the resign block. However, you may enroll on the barrier inside this, nesting enroll and resign blocks as much as you like

Instances

(Enum phase, Bounded phase, Eq phase) => Enrollable PhasedBarrier phase

Enrollable BroadcastChanin a

enrollPair :: (Enrollable b p, Enrollable b' p') => (b p, b' p') -> ((Enrolled b p, Enrolled b' p') -> CHP a) -> CHP a

Like enroll but enrolls on the given pair of barriers

enrollList :: Enrollable b p => [b p] -> ([Enrolled b p] -> CHP a) -> CHP a

Like enroll but enrolls on the given list of barriers