Hi Thanks for the super fast response, Still a little confused. If coll is set to nil before reduce is called, then what is reduce called with?
On Tuesday, February 5, 2013 3:21:14 PM UTC, Herwig Hochleitner wrote: > > Clojure has a feature called locals clearing, which sets 'coll to nil > before calling reduce in test1, because the compiler can prove it won't be > used afterwards. > In test2, coll has to be retained, because reduce is called a second time > on it. > > > 2013/2/5 N8Dawgrr <nathan.r...@gmail.com <javascript:>> > >> If the head is retained on a lazy sequence we have a potential memory >> leak. >> >> I set my JVM memory low, 64mb and ran the following: >> >> user> (defn test1 [coll] (reduce + coll)) >> #'user/test1 >> user> (test1 (take 10000000 (iterate inc 0))) >> 49999995000000 >> user> >> >> Now if we do: >> >> user> (defn test2 [coll] [(reduce + coll) (reduce + coll)]) >> #'user/test2 >> user> (test2 (take 10000000 (iterate inc 0))) >> OutOfMemoryError Java heap space [trace missing] >> user> >> >> Which OOMs as expected. The question is, why doens't the first example >> blow up? What magics happening? >> >> I would expect coll which is a function argument to be retained by the >> garbage collector and hence blow up. >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> 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+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- -- 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/groups/opt_out.
