For the record, I ended up using core.async/merge instead, but I modified it to also return the channel for each value, as [v c] -- similarly to alts!
On Saturday, 26 September 2015 02:29:17 UTC+1, Stathis Sideris wrote: > > Hello, > > I'm trying to process messages from 2 core.async channels at the same time > using alts!! but I'm running into problems when one of the channels closes > early. Specifically I have this function: > > (defn >print [a b] > (loop [limit 20] ;;limit to prevent infinite loop demonstrated below > (let [[v c] (alts!! [a b] :default ::done)] > (if (and (not= c :default) (> limit 0)) > (do > (if (= c a) > (println "a:" v) > (println "b:" v)) > (recur (dec limit)))))) > nil) > > If I run this, it works as expected: > > (let [a (chan 10) > b (chan 10)] > (>!! a 1) > (>!! a 1) > (>!! a 1) > (>!! a 1) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>print a b)) > > Output: > > b: 2 > a: 1 > a: 1 > b: 2 > b: 2 > a: 1 > b: 2 > b: 2 > a: 1 > > If I close "a" early... > > (let [a (chan 10) > b (chan 10)] > (>!! a 1) > (close! a) > (>!! a 1) > (>!! a 1) > (>!! a 1) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>!! b 2) > (>print a b)) > > This is what I get: > > a: 1 > b: 2 > b: 2 > b: 2 > a: nil > a: nil > b: 2 > b: 2 > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > a: nil > > This code would continue running forever if it wasn't for the "limit" > condition above. Am I using alts!! in a manner it's not meant to be used? > > Thanks, > > Stathis > > -- 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.
