Spawning a fiber will disable effect handlers installed after main loop

Learning
,
4

Eio.Fiber.both f g runs f and g concurrently in the context of the Eio scheduler (I think?). What you want is some both_inplace f g that runs f and g in the context where both_inplace was called.

I don’t think anything fundamentally prevents this, I think a simple local overriding of Yield would work:

let finish f =
  ignore @@
  deep_handle f () with
  | Yield (), k -> k ()

let rec both_inplace f g =
  ignore @@
  shallow_handle f () with
  | Yield (), k -> both_inplace g k
  | return v -> finish g

Of course that is the most basic local scheduler possible, Eio would probably want something more involved that adds the two threads into the thread’s pool, it’s just not implemented.

1 Like