effect-language

• explicit effect turns off orphan rules, global effects not.

• effect aliases make syntax nicer

• effects replace traits

• effects:

  • convert
  • allocator
  • async
  • const not, it's the lack of capabilities of a function
  • io (bundle of other effects)

• some effects can be "main effects" with which main is executed like the allocator main effect.

• Some effects can be implicit but which handler runs must never be a surprise

• Range of power: trait to async

• Tail resumptive --> Trait, effects can be non-tail resumptive

• Move types

effect Convertable<A, B> {
    fn convert(A) -> B;
}

struct X;
struct Y;

impl Convertable<X, Y> {
    fn convert(self: X) -> Y {
        Y
    }
}

fn convert() {

}

fn main() {
    let a = X;
    let b = a.convert();
}

weaker effect handlers with still async support: https://www.microsoft.com/en-us/research/publication/effect-handlers-evidently/