Polysemy.Async

Effect

data Async m a where

An effect for spawning asynchronous computations.

The Maybe returned by async is due to the fact that we can't be sure an Error effect didn't fail locally.

Since: 0.5.0.0

Constructors

Async :: m a -> Async m (Async (Maybe a))

Await :: Async a -> Async m a

Instances

type DefiningModule Async

Defined in Polysemy.Async

type DefiningModule Async = "Polysemy.Async"

Actions

async :: forall r a. MemberWithError Async r => Sem r a -> Sem r (Async (Maybe a))

await :: forall r a. MemberWithError Async r => Async a -> Sem r a

Interpretations

asyncToIO :: LastMember (Embed IO) r => Sem (Async ': r) a -> Sem r a

A more flexible --- though less performant --- version of lowerAsync.

This function is capable of running Async effects anywhere within an effect stack, without relying on an explicit function to lower it into IO. Notably, this means that State effects will be consistent in the presence of Async.

Since: 1.0.0.0

lowerAsync

Arguments

:: Member (Embed IO) r

=> (forall x. Sem r x -> IO x)

Strategy for lowering a Sem action down to IO. This is likely some combination of runM and other interpreters composed via .@.

-> Sem (Async ': r) a

-> Sem r a

Run an Async effect via in terms of async.

Since: 1.0.0.0