The most versatile way to do this is a pattern, I like to call concatenated lists of strings.
You implement the parts as functions returning sequences of strings. You combine parts with concat. And map parts over input data with mapcat. Interpose and interleave have the role of str/join. Another useful macro for this style is forcat here: https://github.com/webnf/webnf/blob/master/base/src/webnf/base/utils.clj#L32 At the very top level, you can either (apply str (toplevel-part data)) or write the string parts directly to a socket, like ring does. In clojure, this is already pretty efficient, thanks to lazy sequences. (do (time (->> data-struct (map #(interpose ", " (vals %))) (interpose [\newline]) (apply concat) (apply str))) nil) ; => "Elapsed time: 1104.311277 msecs" If you still want to save on the allocation of the lazy sequence, you could write it in reducer style with a StringBuilder as state and .append as a step function. (defn interpose-xf "A transducer version of interpose" [sep] (fn [xf] (let [is-first (volatile! true)] (completing (fn [s v] (-> (if @is-first (do (vreset! is-first false) s) (xf s sep)) (xf v))))))) (defn sb-append [sb s] (.append ^StringBuilder sb (str s))) (do (time (str (transduce (comp (map #(eduction (comp (map val) (interpose-xf ", ")) %)) (interpose-xf [\newline]) cat) sb-append (StringBuilder.) data-struct))) nil) ; => "Elapsed time: 578.444552 msecs" -- 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.
