Hi sampii, The problem, as I see it (& as Konrad suggested above), is that you're not passing *functions* to (alt); you're passing values returned from function calls, even though in the case of the sub-functions you define those returned values are functions. Functions evaluate to themselves, so if you can write your code to pass functions to (alt), e.g.
(alt #(sub-function1 c) #(sub-function2 c) #(sub-fuction3 c)) you should be golden. Just to show it can be done, if you make the args to alt be (defn mmf [c] (alt #(sub-one c) #(sub-two c) #(sub-three c))) (note the #() reader macro)), & if you modify the definition of alt to be (defn alt [& funcs] (fn [tokens] (some #((%) tokens) funcs))) (note the extra set of parens around % -- so that the #(sub-one c) funcs get called, then their return values likewise get called), you get user=> ((mmf "context") [:a :b :c]) 1 context 2 context true Of course it would be more straightforward to drop the intermediate step of the anonymous functions -- #(sub-one c) -- which return yet another function -- (fn [c] true) -- say, by passing the equivalent of (fn [c] true) directly to alt, but I don't know your actual use case. My recommendation -- to passing function -- is simple enough that I feel like I might be missing something important from your question, but in case I'm not I didn't want you to think your only recourse was the full machinery of delay/force. Transcript follows. Best, Perry user=> (defn alt [& funcs] (fn [tokens] (some #((%) tokens) funcs))) #'user/alt user=> (defn sub-one [c] (println 1 c) (fn [x] false)) #'user/sub-one user=> (defn sub-two [c] (println 2 c) (fn [x] true)) #'user/sub-two user=> (defn sub-three [c] (println 3 c) (fn [x] false)) #'user/sub-three user=> (defn mmf [c] (alt #(sub-one c) #(sub-two c) #(sub-three c))) #'user/mmf user=> ((mmf "context") [:a :b :c]) 1 context 2 context true --~--~---------~--~----~------------~-------~--~----~ 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 clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
