chp-1.8.0: An implementation of concurrency ideas from Communicating Sequential Processes

Control.Concurrent.CHP.Utils

Description

A collection of useful functions to use with the library.

The most useful operation is pipeline which you can use to wire up a list of processes into a line, and run them. The corresponding |->| operator is a simple binary version that can be a little more concise. When the pipeline has channels going in both directions rather than just one, dualPipeline and/or |<->| can be used. Several other variants on these functions are also provided, including operators to use at the beginning and ends of pipelines.

Most of the functions in this module are superseded or generalised by those in the Control.Concurrent.CHP.Connect module since version 1.7.0, so you should look to use those connectors rather than these, as the connects in this module may be removed at some point in the future.

Synopsis

Documentation

wireCycle :: Channel r w => [r a -> w a -> proc] -> CHP [proc]Source

Wires given processes up in a forward cycle. That is, the first process writes to the second, and receives from the last. It returns the list of wired-up processes, which you will almost certainly want to run in parallel.

wireDualCycle :: (Channel r w, Channel r' w') => [(r a, w' b) -> (r' b, w a) -> proc] -> CHP [proc]Source

Like wireCycle, but works with processes that connect with a channel in both directions.

This function was added in version 1.4.0.

wirePipeline :: forall a r w proc. Channel r w => [r a -> w a -> proc] -> r a -> w a -> CHP [proc]Source

Wires the given processes up in a forward pipeline. The first process in the list is connected to the given reading channel-end (the first parameter) and the writing end of a new channel, A. The second process is wired up to the reading end of A, and the writing end of the next new channel, B. This proceeds all the way to the end of the list, until the final process is wired to the reading end of Z (if you have 27 processes in the list, and therefore 26 channels in the middle of them) and the second parameter. The list of wired-up processes is returned, which you can then run in parallel.

wireDualPipeline :: forall a b r w r' w' proc. (Channel r w, Channel r' w') => [(r a, w' b) -> (r' b, w a) -> proc] -> (r a, w' b) -> (r' b, w a) -> CHP [proc]Source

Like wirePipeline, but works with processes that connect with a channel in both directions.

This function was added in version 1.4.0.

pipeline :: [Chanin a -> Chanout a -> CHP b] -> Chanin a -> Chanout a -> CHP [b]Source

A specialised version of wirePipeline. Given a list of processes, composes them into an ordered pipeline, that takes the channel-ends for the sticking out ends of the pipeline and gives a process that returns a list of their results. This is equivalent to wirePipeline, with the return value fed to runParallel.

Added in version 1.0.2.

dualPipeline :: [(Chanin a, Chanout b) -> (Chanin b, Chanout a) -> CHP c] -> (Chanin a, Chanout b) -> (Chanin b, Chanout a) -> CHP [c]Source

Like pipeline, but works with processes that connect with a channel in both directions.

This function was added in version 1.4.0.

cycle :: [Chanin a -> Chanout a -> CHP b] -> CHP [b]Source

A specialised version of wireCycle. Given a list of processes, composes them into a cycle and runs them all in parallel. This is equivalent to wireCycle with the return value fed into runParallel.

Added in version 1.0.2.

dualCycle :: [(Chanin a, Chanout b) -> (Chanin b, Chanout a) -> CHP c] -> CHP [c]Source

Like cycle, but works with processes that connect with a channel in both directions.

This function was added in version 1.4.0.

(|->|) :: (a -> Chanout b -> CHP ()) -> (Chanin b -> c -> CHP ()) -> a -> c -> CHP ()Source

Process composition. Given two processes, composes them into a pipeline, like function composition (but with an opposite ordering). The function is associative. Using wirePipeline will be more efficient than foldl1 (|->|) for more than two processes.

The type for this process became more specific in version 1.2.0.

(|->|^) :: Show b => (a -> Chanout b -> CHP ()) -> (String, Chanin b -> c -> CHP ()) -> a -> c -> CHP ()Source

Like (|->|), but labels the channel and uses show for the traces.

Added in version 1.5.0.

(|<->|) :: (a -> (Chanin b, Chanout c) -> CHP ()) -> ((Chanin c, Chanout b) -> d -> CHP ()) -> a -> d -> CHP ()Source

Process composition that works with processes that connect with a channel in both directions. Like (|->|), but connects a channel in each direction.

This function was added in version 1.4.0.

(|<-|) :: (Chanin b -> c -> CHP ()) -> (a -> Chanout b -> CHP ()) -> a -> c -> CHP ()Source

The reversed version of the other operator.

The type for this process became more specific in version 1.2.0.

(->|) :: (Chanout b -> CHP ()) -> (Chanin b -> c -> CHP ()) -> c -> CHP ()Source

A function to use at the start of a pipeline you are chaining together with the |->| operator. Added in version 1.2.0.

(|->) :: (a -> Chanout b -> CHP ()) -> (Chanin b -> CHP ()) -> a -> CHP ()Source

A function to use at the end of a pipeline you are chaining together with the |->| operator. Added in version 1.2.0.

(|<->) :: (a -> (Chanin b, Chanout c) -> CHP ()) -> ((Chanin c, Chanout b) -> CHP ()) -> a -> CHP ()Source

A function to use at the start of a pipeline you are chaining together with the |<->| operator. Added in version 1.4.0.

(<->|) :: ((Chanin b, Chanout c) -> CHP ()) -> ((Chanin c, Chanout b) -> a -> CHP ()) -> a -> CHP ()Source

A function to use at the end of a pipeline you are chaining together with the |<->| operator. Added in version 1.4.0.