Thanks for the help to both of you! Question, does it seem heavy handed to do it this way? I mean, atoms are more for thread-safety, aren't they? I don't have threads so it seems a bit much to use atoms for this. Am I better off using recur and trying to loop? Or is this considered an idiomatic way to handle mutable data in Clojure? I always found wrapping up mutable data in a closure as we did in Scheme to be pretty elegant, but maybe something like that goes against the desire of Clojure to protect against concurrent modification, is that about right?
Thanks again! On Thursday, April 19, 2012 10:01:23 PM UTC-5, Gaz wrote: > > to answer your question directly, you would need to do something like > this to make it work the way your example is set up: > > (defn new-game [] > (let [board (atom (into [] (repeat 9 nil)))] > (fn [n & [i]] > (cond > (= n :x) (swap! board assoc i 'x) > (= n :o) (swap! board assoc i 'o) > (= n :print) (println @board))))) > > (def g1 (new-game)) > > (g1 :x 0) > (g1 :print) > > On Thu, Apr 19, 2012 at 9:58 PM, Armando Blancas <abm221...@gmail.com> > wrote: > > You could keep the board in an atom so it can mutate; then try to find > maybe > > two good places for mutation to happen, your move and the program's. With > > the rest being functional you'll avoid the problems of global state while > > not being forced to fit your logic into a loop of some re-binding that > > simulates mutation. > > > > > > On Thursday, April 19, 2012 3:21:56 PM UTC-7, Craig Ching wrote: > >> > >> Ok, I've read that what I want to do is a no no. But this is the sort > of > >> thing I did in Scheme about 20 years ago (and because of that I'm > probably > >> misremembering ;-)). > >> > >> Basically I'm learning clojure and thought I'd write a tic tac toe game. > >> But not any tic tac toe, I want to write one where I can have multiple > >> games going simultaneously. Something like: > >> > >> (def g1 (new-game)) > >> (def g2 (new-game)) > >> > >> (g1 :x 0) > >> (g1 :print) > >> (g2 :x 5) > >> (g2 :print) > >> > >> So the schemer in me (and probably the imperative programmer as well) > >> thought I could return a clojure that encapsulates the board value, > >> something like this: > >> > >> (defn new-game [] > >> > >> (let [board (into [] (repeat 9 nil))] > >> > >> (fn [n i] > >> > >> (cond > >> > >> (= n :x)(set! board (assoc board i 'x)) > >> > >> (= n :o)(set! board (assoc board i 'o)) > >> > >> (= n :print) (println board))))) > >> > >> > >> Of course I get an error saying I can't bind to the non-mutable board. > >> > >> I'm really new to Clojure, so apologies if this is really basic for this > >> list. Can I do what I want or can someone point me in the right > direction? > >> I've seen some other tic tac toe implementations on github, but they > use > >> recur to track state and I was hoping there was a cleaner idiomatic way > than > >> that. > >> > >> Thanks! > >> > > -- > > 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
