s5bug/cxxeffect

An "experiment" to create functional streams in C++

cxxeffect

api goals

type	explanation
⊥	bottom/empty/never type. cannot be created lawfully
⊤	top/unit/void type. all instances are equal to eff::top()
α + β	either α or β
α × β	both α and β
callback<α>	(exception + α) → ⊤, a callback that accepts a failure or success
outcome<α>	⊤ + exception + α, either cancelled (⊤), errored, or completed
poll	a polymorphic (A : Type) → task<A> → task<A>

task

Represents a program with a specific result type.

function	type
async	(callback<α> → task<option<task<⊤>>>) → task<α>
async_	(callback<α> → ⊤) → task<α>
blocking	(⊤ → α) → task<α>
bracket	task<α> → (α → task<β>) → (α → outcome<β> → task<⊤>) → task<β>
canceled	task<⊤>
delay	(⊤ → α) → task<α>
never	task<⊥>
pure	α → task<α>
race	task<α> → task<β> → task<(α × fiber<β>) + (fiber<α> × β)>
uncancelable	(poll → task<α>) → task<α>
as	task<α> → β → task<β>
flatMap	task<α> → (α → task<β>) → task<β>
map	task<α> → (α → β) → task<β>
start	task<α> → task<fiber<α>>

fiber

Represents an in-progress computation.

function	type
cancel	task<⊤>
join	task<outcome<α>>

resource

Represents a resource that can be acquired and released.

function	type
flatMap	resource<α> → (α → resource<β>) → resource<β>
map	resource<α> → (α → β) → resource<β>
use	resource<α> → (α → task<β>) → task<β>

dispatcher

A way to run pure code / tasks in impure / synchronous environments.

function	type
make_dispatcher	resource<dispatcher>
unsafeToFutureCancellable	dispatcher → task<α> → (future<α> × (⊤ → future<α>))
unsafeToFuture	dispatcher → task<α> → future<α>
unsafeRunAndForget	dispatcher → task<α> → ⊤