On Sun, 20 Mar 2011 08:47:30 -0700 (PDT)
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)))
>
> 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.
Since nobody answered the implied question: yes, you're right. The fix
is to just remove the ()'s from fib-seq to reference it directly, like
so:
(reduce + (for [fib fib-seq :while (< fib 4000000) :when (even? fib)] fib))
Note that I replaced the filter with the for loops :when test. No real
reason, it just feels more natural to use what for offers since you
started with it. Personally, I'd probably use Daniel's
filter/take-while solution.
<mike
--
Mike Meyer <m...@mired.org> http://www.mired.org/consulting.html
Independent Software developer/SCM consultant, email for more information.
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