I'm trying to understand the difference between next and rest, so I've taken clojure's implementation of some of the collection functions to view how those functions use them. The source code of reduce is (I've marked in red the calls than I do not understand).
(def reduce (fn r ([f coll] (let [s (seq coll)] (if s (r f (first s) (next s)) (f)))) ([f val coll] (let [s (seq coll)] (if s (if (chunked-seq? s) (recur f (.reduce (chunk-first s) f val) (chunk-next s)) (recur f (f val (first s)) (next s))) val))))) In the recur calls, the implementation uses next but the first think we do with the collection is seq. I've always been told that (next s) == (seq (rest s)) so, do we execute seq twice? Could the same recur call be done using rest? What is more idiomatic? Thanks, Juan Manuel -- 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