Control.Eff.Concurrent.Api.Observer

Observer Effects

This module supports the implementation of observers and observables. One use case is event propagation. The tools in this module are tailored towards Api servers/clients.

Observation API

class (Typeable p, Observable o) => Observer p o where

An Api index that support observation of the another Api that is Observable.

Minimal complete definition

observationMessage

Methods

observationMessage :: Server o -> Observation o -> Api p Asynchronous

Wrap the Observation and the ProcessId (i.e. the Server) that caused the observation into a Api value that the Observable understands.

Instances

Observable o => Observer (CallbackObserver o) o

Defined in Control.Eff.Concurrent.Api.Observer

Methods

observationMessage :: Server o -> Observation o -> Api (CallbackObserver o) Asynchronous

class (Typeable o, Typeable (Observation o)) => Observable o where

An Api index that supports registration and de-registration of Observers.

Minimal complete definition

registerObserverMessage, forgetObserverMessage

Associated Types

data Observation o

Type of observations visible on this observable

Methods

registerObserverMessage :: SomeObserver o -> Api o Asynchronous

Return the Api value for the cast_ that registeres an observer

forgetObserverMessage :: SomeObserver o -> Api o Asynchronous

Return the Api value for the cast_ that de-registeres an observer

notifyObserver :: (SetMember Process (Process q) r, Observable o, Observer p o, HasCallStack) => SchedulerProxy q -> Server p -> Server o -> Observation o -> Eff r ()

Send an Observation to an Observer

registerObserver :: (SetMember Process (Process q) r, Observable o, Observer p o, HasCallStack) => SchedulerProxy q -> Server p -> Server o -> Eff r ()

Send the registerObserverMessage

forgetObserver :: (SetMember Process (Process q) r, Observable o, Observer p o) => SchedulerProxy q -> Server p -> Server o -> Eff r ()

Send the forgetObserverMessage

Generalized observation

data SomeObserver o where

An existential wrapper around a Server of an Observer. Needed to support different types of observers to observe the same Observable in a general fashion.

Constructors

SomeObserver :: (Show (Server p), Typeable p, Observer p o) => Server p -> SomeObserver o

Instances

Eq (SomeObserver o)

Defined in Control.Eff.Concurrent.Api.Observer

Methods

(==) :: SomeObserver o -> SomeObserver o -> Bool

(/=) :: SomeObserver o -> SomeObserver o -> Bool

Ord (SomeObserver o)

Defined in Control.Eff.Concurrent.Api.Observer

Methods

compare :: SomeObserver o -> SomeObserver o -> Ordering

(<) :: SomeObserver o -> SomeObserver o -> Bool

(<=) :: SomeObserver o -> SomeObserver o -> Bool

(>) :: SomeObserver o -> SomeObserver o -> Bool

(>=) :: SomeObserver o -> SomeObserver o -> Bool

max :: SomeObserver o -> SomeObserver o -> SomeObserver o

min :: SomeObserver o -> SomeObserver o -> SomeObserver o

Show (SomeObserver o)

Defined in Control.Eff.Concurrent.Api.Observer

Methods

showsPrec :: Int -> SomeObserver o -> ShowS

show :: SomeObserver o -> String

showList :: [SomeObserver o] -> ShowS

notifySomeObserver :: (SetMember Process (Process q) r, Observable o, HasCallStack) => SchedulerProxy q -> Server o -> Observation o -> SomeObserver o -> Eff r ()

Send an Observation to SomeObserver.

data Observers o

Internal state for manageobservers

manageObservers :: Eff (State (Observers o) ': r) a -> Eff r a

Keep track of registered Observers Observers can be added and removed, and an Observation can be sent to all registerd observers at once.

addObserver :: (SetMember Process (Process q) r, Member (State (Observers o)) r, Observable o) => SomeObserver o -> Eff r ()

Add an Observer to the Observers managed by manageObservers.

removeObserver :: (SetMember Process (Process q) r, Member (State (Observers o)) r, Observable o) => SomeObserver o -> Eff r ()

Delete an Observer from the Observers managed by manageObservers.

notifyObservers :: forall o r q. (Observable o, SetMember Process (Process q) r, Member (State (Observers o)) r) => SchedulerProxy q -> Observation o -> Eff r ()

Send an Observation to all SomeObservers in the Observers state.

Callback Observer

data CallbackObserver o

An Observer that schedules the observations to an effectful callback.

Instances

Show (Observation o) => Show (Api (CallbackObserver o) r)

Defined in Control.Eff.Concurrent.Api.Observer

Methods

showsPrec :: Int -> Api (CallbackObserver o) r -> ShowS

show :: Api (CallbackObserver o) r -> String

showList :: [Api (CallbackObserver o) r] -> ShowS

Observable o => Observer (CallbackObserver o) o

Defined in Control.Eff.Concurrent.Api.Observer

Methods

observationMessage :: Server o -> Observation o -> Api (CallbackObserver o) Asynchronous

data Api (CallbackObserver o) r

Defined in Control.Eff.Concurrent.Api.Observer

data Api (CallbackObserver o) r where

• CbObserved :: Api (CallbackObserver o) Asynchronous

spawnCallbackObserver :: forall o r q. (SetMember Process (Process q) r, Typeable o, Show (Observation o), Observable o, Member (Logs String) q) => SchedulerProxy q -> (Server o -> Observation o -> Eff (Process q ': q) Bool) -> Eff r (Server (CallbackObserver o))

Start a new process for an Observer that schedules all observations to an effectful callback.

spawnLoggingObserver :: forall o r q. (SetMember Process (Process q) r, Typeable o, Show (Observation o), Observable o, Member (Logs String) q) => SchedulerProxy q -> Eff r (Server (CallbackObserver o))

Use spawnCallbackObserver to create a universal logging observer, using the Show instance of the Observation. | Start a new process for an Observer that schedules all observations to an effectful callback.

Since: extensible-effects-concurrent-0.3.0.0