Patrick, I can't speak for the OP, but I found his question interesting and I'd like to compliment you on your response. You gave alternative "Clojure-like ways" to do the same thing, but in addition to that you actually answered his question.
I find these kinds of responses very instructive because you don't ignore the OP's request when juxtaposing your alternative suggestion. It helps them make a better decision about what route they want to go. Thanks, - Greg On Feb 10, 2010, at 10:40 AM, CuppoJava wrote: > It looks like you want to implement something akin to what other > languages call "generators". > In Clojure, we generally use list comprehensions to get (almost) the > same effect, but it's a little cleaner in my opinion. > > eg. in your first two examples > (collect > (doseq [ n (range 10)] > (when (even? n) (emit n)))) > > ;;becomes: > (for [n (range 10) :when (even? n)] n) > > (collect > (doseq [ n (range 10)] > (when (even? n) > (emit n) > (emit (* 2 n))))) > > ;;becomes: > (for [n (range 10)] > (if (even? n) > n > (* 2 n))) > > It's almost as expressive as what you want, except that decomposes > nicely and efficiently into filter and map functions. > > I would recommend that you try those out first and see how they feel. > > If you REALLY want your emit and collect functions, here's one > possible implementation. The only tricky part you need to watch out > for is the ~'collector escaping. > > (def -collector) > (defn emit [x] > (set! -collector (conj -collector x))) > (defmacro collect [& body] > `(binding [~'-collector []] > ~...@body > ~'-collector)) > > Your examples work nicely with this. > > Hope this is helpful > -Patrick > > -- > 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
