Copyright	Copyright 2024 Shea Levy.
License	Apache-2.0
Maintainer	shea@shealevy.com
Safe Haskell	Safe-Inferred
Language	GHC2021

Observe.Event.Backend.Data

Description

This module provides the DataEventBackend EventBackend for consuming events by representing them as ordinary Haskell data.

Synopsis

newDataEventBackend :: forall m selector. (PrimMonad m, ParametricFunctor m) => m (DataEventBackend m selector)
getEvents :: PrimMonad m => DataEventBackend m selector -> m (Seq (Maybe (DataEvent selector)))
data DataEvent selector = forall f.DataEvent {
- idx :: !Int
- selectors :: !(Selectors selector f)
- parent :: !(Maybe (Either Int (DataEvent selector)))
- causes :: ![Either Int (DataEvent selector)]
- err :: !(Maybe SomeException)
- fields :: !(Seq f)
- instant :: !Bool
}
data Selectors selector field where
- Leaf :: selector field -> Selectors selector field
- (:/) :: selector field -> Selectors (SubSelector field) field' -> Selectors selector field'
data DataEventBackend m selector

Documentation

newDataEventBackend :: forall m selector. (PrimMonad m, ParametricFunctor m) => m (DataEventBackend m selector) Source #

Allocate a new DataEventBackend

getEvents :: PrimMonad m => DataEventBackend m selector -> m (Seq (Maybe (DataEvent selector))) Source #

Read the events that have been emitted using the DataEventBackend

A Nothing indicates an event that hasn't been finalized.

data DataEvent selector Source #

A representation of an event.

Constructors

forall f. DataEvent

Fields

idx :: !Int
This event's index in the sequence of event creations.
selectors :: !(Selectors selector f)
The selector used to initialize the event
parent :: !(Maybe (Either Int (DataEvent selector)))
The parent of this DataEvent, if any.
Left n means the parent was the n'th event but wasn't finalized.
causes :: ![Either Int (DataEvent selector)]
The causes of this DataEvent.
Left n means the cause was the n'th event but wasn't finalized.
err :: !(Maybe SomeException)
The error which ended the event, if any
fields :: !(Seq f)
The fields which were added to the event
instant :: !Bool
Whether the event was emitted instantly.

data Selectors selector field where Source #

A nested sequence of selectors, starting from a given root selector family and ending in a selector selecting a given field type.

For example, given:

data FooSelector :: Type -> Type where Foo :: FooSelector FooField
data FooField
type instance SubSelector FooField = BarSelector
data BarSelector :: Type -> Type where Bar :: BarSelector BarField
data BarField
type instance SubSelector BarField = NoEventsSelector

Then Leaf Foo is a sequence Selectors picking out an Event with field type FooField, and Foo :/ Leaf Bar is a sequence of Selectors picking out an Event with field type BarField underneath an Event with field type FooField.

See the selector and field documentation for more details.

Constructors

Leaf :: selector field -> Selectors selector field
(:/) :: selector field -> Selectors (SubSelector field) field' -> Selectors selector field' infixr 5

data DataEventBackend m selector Source #

An EventBackend for consuming events by representing them as ordinary Haskell data.

Create a new one with newDataEventBackend. Get the event data with getEvents.

Instances

Instances details

(PrimMonad m, ParametricFunctor m) => EventBackendIn m (DataEventBackend m selector) Source #	Consume events by representing them as ordinary Haskell data.
Instance details Defined in Observe.Event.Backend.Data Methods newEvent :: DataEventBackend m selector -> EventParams (RootSelector (DataEventBackend m selector)) field (EventReference (BackendEvent (DataEventBackend m selector))) -> m (BackendEvent (DataEventBackend m selector) field) Source # newInstantEvent :: DataEventBackend m selector -> EventParams (RootSelector (DataEventBackend m selector)) field (EventReference (BackendEvent (DataEventBackend m selector))) -> m (EventReference (BackendEvent (DataEventBackend m selector))) Source #
EventBackend (DataEventBackend m selector) Source #	Consume events by representing them as ordinary Haskell data.
Instance details Defined in Observe.Event.Backend.Data Associated Types type BackendEvent (DataEventBackend m selector) :: Type -> Type Source # type RootSelector (DataEventBackend m selector) :: Type -> Type Source #
type BackendEvent (DataEventBackend m selector) Source #
Instance details Defined in Observe.Event.Backend.Data type BackendEvent (DataEventBackend m selector)
type RootSelector (DataEventBackend m selector) Source #
Instance details Defined in Observe.Event.Backend.Data type RootSelector (DataEventBackend m selector) = selector