I am working with bulk sources and sinks, that is with a type like: Source m [a] Sink [a] m () The problem is that I would like to work on individual values in my conduit. I can have this: concat :: (Monad m) => Conduit [a] m a concat = awaitForever (mapM_ yield) But how can I do it the other way around ? I suppose it involves pattern matching on the different states my conduit might me in. But is that even possible to do it in a "non blocking" way, that is catenate data while there is something to read (up to a certain threshold), and send it as soon as there is nothing left to read ? Or doesn't that make any sense in the context of Conduits (in the sense that this conduit will be recheck for input before the upstream conduits will have a chance to operate) ? Another approach would be to have a map equivalent: conduitMap :: Conduit i m o -> Conduit [i] m [o] But I am not sure how to do this either ...