Hi Leslie, On Tuesday, July 14, 2015 at 1:38:02 PM UTC+2, leslie...@googlemail.com wrote: > > When programming with functions this kind of issue is solved quite > elegantly by using a for comprehension: > > Not a solution but a comment. In a for comprehension with usual types (Future/Option/Either/Try) the calculation is also cut short on the first error. So, it may not differ so much in that regard.
However, streams are different in another way: a Flow[T, U] is more than just a function T => U, it's more like a T => Seq[U] that can create any number of results for any input element. This makes it hard to create something like an `eitherFlow(leftFlow: Flow[L, U], rightFlow: Flow[R, U]): Flow[Either[L, R], U]` that would bypass errors around some components because in general you somehow need to constrain the argument flows to produce exactly one output element for each input element. Even then you need to prevent two subsequent elements `Right(r)`, `Left(l)` to start a race between the left and right branch (if you are interested in keeping the order). I think that's the main problem, that it's hard to come with an exact specification for a general element that would solve the problem in all cases. akka-http has lots of places where we do pass "control information" around actual processing. However, in the end we had to hand-tune the bypass in most places because more general solutions didn't work out because of some pecularities of the needed semantics. Johannes -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
