Hi Andy, To give you some context on this, `put!` will return true if the thing directly downstream accepts the value (in this case, the stream). The fact that the callback in `consume` fails is between the stream and the callback, and is not propagated all the way back (though the exception will cancel the `consume`, which will cause the stream to close). The approach described by Atamert is a reasonable one to get the desired result.
Zach On Sunday, August 9, 2015 at 9:13:30 PM UTC-7, Andy Chambers wrote: > > Hey All, > > I'm trying to build a library that exposes manifold streams for data > producing applications. The intention > would be for these apps to s/put! to a sink stream returned by the > producer function. However, I need to > take the value that is put in and pipe it into some other function before > I know whether there is an error > and if there is an error, I'd like to propagate it back to the caller. > > I understand that the value returned by put! is a deferred, and how to set > the error state of a deferred but I > don't understand how I can arrange for the deferred to be manipulated > downstream of where it has been > taken off the stream. > > (defn producer [] > (let [in (s/stream)] > > (s/consume (fn [msg] > (d/future > (prn "oops, going to error now") > (throw (Exception. (str msg))))) in) > > in)) > > @(s/put! (producer) 42) > > As written, you get a success response even though an exception was > triggered by the function that consumes > the "in" stream. Is it possible to re-write this so that the exception > bubbles up to where the put! is deref'd? > > Cheers, > Andy > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
