Thanks Mark, I think that worked!! Sunil. On Sat, Feb 25, 2012 at 10:54 AM, Mark Rathwell <mark.rathw...@gmail.com>wrote:
> Try this (you need to wrap the return val of helper in lazy-seq also): > > (defn pair-sequences-by > ([seq-1 seq-2 f1 f2] > "s1 and s2 are guaranteed to be strictly monotonically increasing > whith respect to f1 and f2 as keys respectively. > The return value is pairs of elements e1 from s1 and e2 from s2 such > that (= (f1 e1) (f2 e2)) is true" > (let [helper (fn helper [s1 s2] > (loop [[x & xs :as wx] s1 [y & ys :as wy] s2] > (when (and x y) > (let [[xk yk] (map #(%1 %2) [f1 f2] [x y])] > (let [cval (compare xk yk)] > (cond > (< cval 0) (recur xs wy) > (= cval 0) (cons [x y] (lazy-seq (helper xs > ys))) > (> cval 0) (recur wx ys)))))))] > (lazy-seq (helper seq-1 seq-2)))) > ([seq-1 seq-2 f] (pair-sequences-by seq-1 seq-2 f f))) > > On Fri, Feb 24, 2012 at 11:36 PM, Sunil S Nandihalli > <sunil.nandiha...@gmail.com> wrote: > > Hi Everybody, > > Can somebody comment if the following piece of code is truely lazy? > > > > > > > > > > (defn pair-sequences-by > > > > > > > > ([seq-1 seq-2 f1 f2] > > > > > > > > "s1 and s2 are guaranteed to be strictly monotonically increasing > whith > > respect to f1 and f2 as keys respectively. > > > > > > > > The return value is pairs of elements e1 from s1 and e2 from s2 such > that > > (= (f1 e1) (f2 e2)) is true" > > > > > > > > (let [helper (fn helper [s1 s2] > > > > > > > > (loop [[x & xs :as wx] s1 [y & ys :as wy] s2] > > > > > > > > (when (and x y) > > > > > > > > (let [[xk yk] (map #(%1 %2) [f1 f2] [x y])] > > > > > > > > (let [cval (compare xk yk)] > > > > > > > > (cond > > > > > > > > (< cval 0) (recur xs wy) > > > > > > > > (= cval 0) (cons [x y] (helper xs ys)) > > > > > > > > (> cval 0) (recur wx ys)))))))] > > > > > > > > (lazy-seq (helper seq-1 seq-2)))) > > > > > > > > ([seq-1 seq-2 f] (pair-sequences-by seq-1 seq-2 f f))) > > > > > > > > > > > > > > https://gist.github.com/e9f6c0ad9bbe535d2d54 > > > > > > > > > > > > > > I am running out of ram when I use this.. so any help would be greatly > > appreciated. > > > > > > > > Thanks, > > Sunil. > > > > -- > > 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 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 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
