We’re delighted to announce that the Ocsigen project has just launched one of its most ambitious changes: moving from Lwt to effects-based concurrency. If this experiment goes well, it will be another step towards simplifying Web development in OCaml, by eliminating the need for monads. Of course …

If I remember correctly, I read somewhere that the development of eio was paused (and indeed it seems there’s not much activity on the repo these days), are you going to use it as announced or are you considering using something actively maintained (miou for instance) ?

We will try to remain as neutral as possible with regard to the choice of the library, in order to be able to switch to another one or even let the choice to the app developer in the future. For our first experiments, we are looking towards Eio and Picos. Eio is probably the most advanced concurren…

Indeed, eio is in a relaxing stable period and we’re spending the time using it to get real work done and getting used to direct style IO. Your fibre library shouldn’t be ever-shifting under your feet.

Are there plans to make Eio compatible with/closer to Picos? It’d be nice to have a unified interface, at least a unified notion of future and trigger and fiber-local storage…

Relaying a question of @Yaron_Minsky on Bluesky because it seems easier to discuss it on the forum, and I’m also curious I wonder what the plan is for dealing with data races. As I understand it, eio doesn’t have any typeful discipline for determining where interleavings might happen, unlike both …

I too am not entirely convinced about direct-style programming for concurrent systems. It’s useful to simplify signatures and avoid some functors with type 'a io := 'a Lwt.t, but signatures become less informative overall. That being said, Lwt is not great in that respect: type information only va…

For what it’s worth, I ported (in a hacky way) eio.core to picos a week or two ago, as proof of concept. open Eio__core let () = Picos_mux_random.run @@ fun () -> let p, r = Promise.create () in Fiber.both (fun () -> Printf.printf "Hello Fiber 1\n%!" Promise.await p; Printf.pri…

[ANN] Ocsigen migrating to effect-based concurrency

Ecosystem

dbuenzli Split this topic March 20, 2025, 11:14am 9

A post was split to a new topic: Direct style for concurrent systems

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[ANN] Ocsigen migrating to effect-based concurrency

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