And do not miss https://github.com/LonoCloud/synthread for more complex cases ;-)
пятница, 1 мая 2015 г., 2:31:05 UTC+3 пользователь Vagmi Mudumbai написал: > > Hi, > > I was introducing one of my colleagues to clojure[1] and we were > trying to parse the reddit json as an exercise. > > (require '(clj-http.client :as client)) > (require '(clojure.data.json :as json)) > > (def ^:const REDDIT-URL "http://reddit.com/r/clojure.json?limit=100";) > (def ^:const headers {:headers {"User-Agent" "showoffclojure.core by > vagmi"}}) > > (let [entries_ (-> REDDIT-URL > (client/get headers) > (:body) > (json/read-str :key-fn keyword) > (:data) > (:children))] > (map :data entries)) > > It would have been nice if we were able to write the map as a part of > the threading macro. So if there were a flip function like in haskell, > we could flip the args to the function hand have the map in the > threading macro. I could not find one so I wrote one. > > (defn flip [fn_] > (fn [x y & args] > (apply fn_ (into [y x] args)))) > > Now I can bring in the map as a part of the -> threading macro. > > (-> REDDIT-URL > (client/get headers) > (:body) > (json/read-str :key-fn keyword) > (:data) > (:children) > ((flip map) :data)) > > This seems to be rather easy and useful and gets rid of the let block. > Are there any implications to performance or impact to laziness by > using flip? This would be useful even on the transduced version of > map like ((flip transduce) (map :data)) on the last expression. > > Regards, > Vagmi > > > [1]: ( > http://blog.tarkalabs.com/2015/04/30/experience-report-introducing-an-experienced-ruby-developer-to-clojure/) > > > and > -- 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.
