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.
