Hi On 20 March 2011 17:47, Christian <soulbea...@gmail.com> wrote: > Hello Tassilo! > > I've tested your code and looked at the Clojure Documentation for > 'for'. Given that, I have written > > (reduce +(filter even? (for [fib (fib-seq) :while (< fib 4000000)] > fib)))
Or using Daniel's suggestion: (reduce + (filter even? (take-while #(< % 4000000) fib-seq))) > This gives me the error 'clojure.lang.LazySeq cannot be cast to > clojure.lang.IFn'. > > I think this is because fib-seq is a var, not a function (although I > was hard-pressed finding out what IFn stood for.) When I omit the () > with [fib (fib-seq)...], the program works just as expected. Yes, that's correct. IFn means something that implements the "Fn" interface, i.e. it acts like a function. There are things in Clojure which are not really functions, but can be used like functions. e.g.: ({:foo "bar"} :foo) or: (:foo {:foo "bar"}) -- Michael Wood <esiot...@gmail.com> -- 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