On Jul 4, 2009, at 6:04 AM, arasoft wrote:
> > Using a fairly recent 1.1 snapshot, I get an OutOfMemoryError for > this: > > (defn fib-seq [] > ((fn more [a b] > (lazy-seq (cons a (more b (+ a b))))) > 0 1) > ) > > (nth (fib-seq) 200000) > > However, this works fine: > > (defn xth [coll i] > (if (zero? i) (first coll) (recur (rest coll) (dec i)))) > > (xth (fib-seq) 200000) > > Am I doing anything wrong, or is this a bug? You aren't doing anything wrong, it's just that recur is a local jump which creates no stack and calling a function recursively is not. In other words Clojure doesn't have built-in tail call elimination, but recur creates the same effect. (I actually prefer this behavior because it's easy to see where you're paying the penalty for recursion and where you aren't, unlike in OCaml, Scheme and Haskell, where it can be easy to get confused about which form is the final position.) — Daniel Lyons --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
