Effect.Aff
- Package
- purescript-aff
- Repository
- purescript-contrib/purescript-aff
#Aff Source
data Aff t0
An Aff a
is an asynchronous computation with effects. The
computation may either error with an exception, or produce a result of
type a
. Aff
effects are assembled from primitive Effect
effects using
makeAff
or liftEffect
.
Instances
#ParAff Source
data ParAff t0
Applicative for running parallel effects. Any Aff
can be coerced to a
ParAff
and back using the Parallel
class.
Instances
Functor ParAff
Apply ParAff
Runs effects in parallel, combining their results.
Applicative ParAff
(Semigroup a) => Semigroup (ParAff a)
(Monoid a) => Monoid (ParAff a)
Alt ParAff
Races effects in parallel. Returns the first successful result or the first error if all fail with an exception. Losing branches will be cancelled.
Plus ParAff
Alternative ParAff
Parallel ParAff Aff
#Canceler Source
newtype Canceler
A cancellation effect for actions run via makeAff
. If a Fiber
is
killed, and an async action is pending, the canceler will be called to
clean it up.
Constructors
Instances
#launchAff_ Source
launchAff_ :: Aff Unit -> Effect Unit
Forks an Aff
from an Effect
context, discarding the Fiber
.
#launchSuspendedAff Source
launchSuspendedAff :: forall a. Aff a -> Effect (Fiber a)
Suspends an Aff
from an Effect
context, returning the Fiber
.
#suspendAff Source
suspendAff :: forall a. Aff a -> Aff (Fiber a)
Suspends an Aff
from within a parent Aff
context, returning the Fiber
.
A suspended Aff
is not executed until a consumer observes the result
with joinFiber
.
#invincible Source
invincible :: forall a. Aff a -> Aff a
Runs an effect such that it cannot be killed.
#cancelWith Source
cancelWith :: forall a. Aff a -> Canceler -> Aff a
Attaches a custom Canceler
to an action. If the computation is canceled,
then the custom Canceler
will be run afterwards.
#bracket Source
bracket :: forall a b. Aff a -> (a -> Aff Unit) -> (a -> Aff b) -> Aff b
Guarantees resource acquisition and cleanup. The first effect may acquire some resource, while the second will dispose of it. The third effect makes use of the resource. Disposal is always run last, regardless. Neither acquisition nor disposal may be cancelled and are guaranteed to run until they complete.
#generalBracket Source
generalBracket :: forall a b. Aff a -> BracketConditions a b -> (a -> Aff b) -> Aff b
A general purpose bracket which lets you observe the status of the bracketed action. The bracketed action may have been killed with an exception, thrown an exception, or completed successfully.
#nonCanceler Source
nonCanceler :: Canceler
A canceler which does not cancel anything.
#fiberCanceler Source
fiberCanceler :: forall a. Fiber a -> Canceler
A canceler from a Fiber.
Re-exports from Control.Monad.Error.Class
#catchError Source
catchError :: forall e m a. MonadError e m => m a -> (e -> m a) -> m a
#throwError Source
throwError :: forall e m a. MonadThrow e m => e -> m a
#try Source
try :: forall e m a. MonadError e m => m a -> m (Either e a)
Return Right
if the given action succeeds, Left
if it throws.
Re-exports from Control.Parallel.Class
#sequential Source
sequential :: forall f m. Parallel f m => f ~> m
This instance is provided for compatibility.
Aff
is always stack-safe within a given fiber. This instance will just result in unnecessary bind overhead.