Hi Sam, Transducers are a new feature, and best practices are still emerging.
Transducing/reducing is always non-lazy, so it's *less* risky to have side effects in a reduce compared with side effects in a lazy sequence. Still, I would offer the same advice I give for lazy sequences. Keep your side-effects as separated as possible from the purely-functional computation that feeds them. Don't put a side-effect in the middle of a chain of map/filter-like operations. Do all your map/filter/whatever with pure functions, then process the entire result non-lazily to do the side effects. The "driver" for that process could be `doseq`, `run!`, `transduce`, or even `reduce`. `doseq` has overhead to allocate the sequence, which the others avoid. –S On Thursday, June 25, 2015 at 2:30:21 PM UTC-4, Sam Raker wrote: > > This seems bad, is this bad: > > (defn to-db > [conn] > (fn > ([val] (upload-to-my-db conn val)) > ([_ val] (upload-to-my-db conn val))) > > (defn -main [] > (transduce my-preprocessing-xf (to-db (get-db-conn)) seq-of-things-to- > preprocess-and-upload)) > > I ask only because > 1) Plugging the side-effecting part into the transducer pipeline seems > cleaner and potentially more efficient than e.g. > (doseq [v (sequence my-preprocessing-xf sea-of-things)] (upload-to-my-db > conn v)) > which is what I was doing > 2) The addition of `run!`[1] in 1.7 seems to perhaps implicitly condone > this kind of thing. There's very little out there about it, though, so I > could very well be wrong. > > > > > [1] > http://conj.io/store/v1/org.clojure/clojure/1.7.0-alpha4/clj/clojure.core/run%21 > -- 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.
