I've got a conduit thing that yields infinitely many values and never exits, which I've given the type ConduitM () o m Void - a bit like Source m o = ConduitM () o m () except that it can't exit due to the Void.

(One side-question: why is Source m o not ConduitM Void o m ()?)

I would now like to get the first item it yields; I'm currently using Data.Conduit.List.head but of course this returns a Maybe o in case the upstream thing exits. Is there a way to do this without that Maybe? I can't see anything obvious, but nor can I think of a terribly good reason why not.

One thing that I was pondering was a kind of fuse operator with a type like ...

... which returns the result of whichever thing exits first. Does such a thing exist? Does it even make sense? If it existed, I think I could use it here as it'd specialise to

and of course (Either Void o) is isomorphic to o so I'd be home and dry.

Having written this, I'm now also struggling to work out what the thing of type ConduitM o Void m o would be. Maybe I'm going about this all the wrong way, or maybe I'm just confused?

Any help greatly appreciated!

Cheers,

David