well, the problem with using def is that you're pinning the head of the sequence to a variable.
if you wrap it in a fn, then you're making a new sequence each time you call the fn. so the head of the sequence isn't attached to anything, only the function that creates it is. On Tue, Dec 9, 2008 at 3:48 PM, Drew Olson <[EMAIL PROTECTED]> wrote: > On Tue, Dec 9, 2008 at 2:28 PM, Stephan Mühlstrasser < > [EMAIL PROTECTED]> wrote: > >> >> On Dec 9, 12:34 am, "harrison clarke" <[EMAIL PROTECTED]> wrote: >> > you're keeping the head of the sequence, and thus all the elements >> between >> > the head and nth. >> > >> > it's because you're using def, basically. >> > >> > > Ok, I'm confused here. Why does wrapping his logic into a > function alleviate this problem? Can you give a more detailed explanation, > I'd like to understand what's going on here. > > - Drew > > >> >> > if you make a function to return the sequence, and pass the result >> directly >> > to nth, without let-binding it or anything, it should work. >> >> Ok, I got it: >> >> user=> (defn triangle-numbers >> [] >> (let [rest-fn >> (fn rest-fn [current cumulated] >> (let [next (+ current cumulated)] >> (lazy-cons next (rest-fn (inc current) next))))] >> (rest-fn 1 0))) >> #'user/triangle-numbers >> user=> (nth (triangle-numbers) 1000000) >> 500001500001 >> user=> (nth (triangle-numbers) 10000000) >> 50000015000001 >> >> Thanks! >> Stephan >> >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ 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 To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
