I'd be careful about writing my own version of mapcat. You might save a call or two on the f function, but you'll probably lose in the general. Try some experiments with larger take numbers. You might be better off concentrating on your f function. I've found that trying to special-case degenerate cases (for empty collections, etc.) has actually hurt my performance, presumably because my cleverness got in the way of hotspot optimizations.
On Aug 22, 2011, at 10:32 AM, Asim Jalis wrote: > user=> (defn f [[x]] (println "computing x:" (inc x)) (vector (inc x))) > #'user/f > user=> (->> (iterate f [0]) (take 0)) > () > user=> (->> (iterate f [0]) (apply concat) (take 0)) > computing x: 1 > computing x: 2 > computing x: 3 > () > user=> (->> (iterate f [0]) (mapcat identity) (take 0)) > computing x: 1 > computing x: 2 > computing x: 3 > () > > Is there a way to rewrite mapcat (or apply concat) so that they don't > evaluate the incoming seq unnecessarily? > > -- > 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 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
