Control.Monad.Coroutine.Nested

A coroutine can choose to launch another coroutine. In this case, the nested coroutines always suspend to their invoker. If a function from this module, such as pogoStickNested, is used to run a nested coroutine, the parent coroutine can be automatically suspended as well. A single suspension can thus suspend an entire chain of nested coroutines.

Nestable coroutines of this kind should group their suspension functors into a Sum. A simple coroutine suspension can be converted to a nested one using functions mapSuspension and liftAncestor. To run nested coroutines, use pogoStickNested, or weave with a NestWeaveStepper.

Documentation

eitherFunctor :: (l x -> y) -> (r x -> y) -> Sum l r x -> y

Like either for the Sum data type.

mapNestedSuspension :: (Functor s0, Functor s, Monad m) => (forall y. s y -> s' y) -> Coroutine (Sum s0 s) m x -> Coroutine (Sum s0 s') m x

Change the suspension functor of a nested Coroutine.

pogoStickNested :: forall s1 s2 m x. (Functor s1, Functor s2, Monad m) => (s2 (Coroutine (Sum s1 s2) m x) -> Coroutine (Sum s1 s2) m x) -> Coroutine (Sum s1 s2) m x -> Coroutine s1 m x

Run a nested Coroutine that can suspend both itself and the current Coroutine.

type NestWeaveStepper s0 s1 s2 m x y z = WeaveStepper (Sum s0 s1) (Sum s0 s2) s0 m x y z

Type of functions capable of combining two child coroutines' CoroutineStepResult values into a parent coroutine. Use with the function weave.

class Functor c => ChildFunctor c where

Class of functors that can contain another functor.

Associated Types

type Parent c :: * -> *

Methods

wrap :: Parent c x -> c x

Instances

(Functor p, Functor s) => ChildFunctor (Sum p s)

class (Functor a, Functor d) => AncestorFunctor a d where

Class of functors that can be lifted.

Methods

liftFunctor :: a x -> d x

Convert the ancestor functor into its descendant. The descendant functor typically contains the ancestor.

Instances

(Functor a, ChildFunctor d, (~) (* -> *) d' (Parent d), AncestorFunctor a d') => AncestorFunctor a d

Functor a => AncestorFunctor a a

liftParent :: forall m p c x. (Monad m, Functor p, ChildFunctor c, p ~ Parent c) => Coroutine p m x -> Coroutine c m x

Converts a coroutine into a child nested coroutine.

liftAncestor :: forall m a d x. (Monad m, Functor a, AncestorFunctor a d) => Coroutine a m x -> Coroutine d m x

Converts a coroutine into a descendant nested coroutine.