[tkz1312]

I had understood that the delimited continuations stuff was more like performance optimisation for the (slow) free monadic effect systems than a fundamentally different theoretical foundation for modelling effects in a pure language?

fwiw we also have fast effect systems in Haskell these days that are more like fancy type sugar on top of the ReaderT over IO style of things (effectful seems to be the most popular).

[ReleaseCandidat]

I've thought that all "native" (in the compiler instead of a library) implementations use (more or less) delimited continuations (some kind of temporary stack moving/copying). OCaml : https://github.com/ocaml-multicore/ocaml-effects-tutorial#3-... And Koka: I haven't found the paper/docs right now.

I know about effectful, but that doesn't use Reader (but provides one) but more or less directly IO (Ref) and "evidence passing", that's why it is faster than the other ones, the drawback is not being able to use non-deterministic effects and noo such thing as coroutines. But I talked about eff ("native" delimited continuations) should be more or less the same, maybe a bit faster, than effectful, but enable non-determinism and coroutines.