Here is something similar pulled from bagotricks "1.5.2", using Java's linked blocking queue; https://github.com/thebusby/bagotricks/blob/master/src/bagotricks.clj#L204-L238
It uses fold instead of reduce to run in parallel, so has a slightly different use case than above. On Mon, Aug 26, 2013 at 10:14 AM, Mikera <mike.r.anderson...@gmail.com>wrote: > Nice idea Jozef! > > Hmmm.... this is another example of why nil-as-end-of-channel is a > slightly problematic design decision for core.async: it makes this kind of > code much more fiddly. > > > On Monday, 26 August 2013 01:47:14 UTC+8, Jozef Wagner wrote: >> >> Hi, >> >> A distinctive feature of reducers is that "reducing is a one-shot thing". >> The common understanding is that reducers are fast for cases where you want >> to process whole collection at once, but for infinite and lazy seqs, you >> have to use good old seqs. >> >> With core.async, it is now easy to create a transformation which produces >> lazy seq from any reducible collection. >> >> (defn lazy-seq* >> [reducible] >> (let [c (chan) >> NIL (Object.) >> encode-nil #(if (nil? %) NIL %) >> decode-nil #(if (identical? NIL %) nil %)] >> (thread >> (reduce (fn [r v] (>!! c (encode-nil v))) nil reducible) >> (close! c)) >> (take-while (complement nil?) (repeatedly #(decode-nil (<!! c)))))) >> >> (def s (lazy-seq* (clojure.core.reducers/map inc (range)))) >> >> (first s) >> >> (take 100 s) >> >> This approach can be also extended to produce chunked seqs and chan >> buffer can also be used to further tune the performance. >> >> JW >> >> -- > -- > 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/groups/opt_out. > -- -- 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/groups/opt_out.
