On Tue, Aug 2, 2011 at 3:11 AM, recurve7 <dan.m...@gmail.com> wrote: > Here's one example where recursion and lack of positional error > feedback make it hard for me, as someone coming from Java, to spot the > error (and seeing "ClassCastException" threw me off and had me > wondering where/how I had done something like that): > > user=> (defn fac [n] (if (= n 1) 1 (* n fac (- n 1)))) > #'user/fac > user=> (fac 3) > java.lang.ClassCastException: user$fac cannot be cast to > java.lang.Number (NO_SOURCE_FILE:0) >
What were you thoughts *before* you asked Google? As being someone who is also coming from Java, this error message seems fairly clear. You've used `fac` when it expects a number. Now, assuming you know how `defn` works, it must be the second instance of `fac` that is causing the issue. Then, since it's expecting a number, assume it is, and then ask yourself why it wouldn't complain if it was a number. Then go from there. Also, keep in mind you're in the REPL, where line numbers aren't all that useful. -- 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
