Re: Exception calling nth on Sets
Hi, Am Sonntag, 14. August 2011 18:59:57 UTC+2 schrieb Despite: In Clojurescript, calling rand-nth on an empty Set results in an Index out of bounds exception, whereas calling it on an empty Vector results in nil. Returning nil for vectors is almost certainly a bug as it should throw an exception according to the docstring of nth. Sincerely Meikel -- 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
Re: Exception calling nth on Sets
I should have done a comparison to original Clojure first. In Clojure, rand-nth on an empty vector does throw an exception, as Meikel says. As does any use of nth with a bad index and no not-found parameter. So that seems to be a bug. But, nth on a set never works in Clojure, throwing java.lang.UnsupportedOperationException: nth not supported on this type: PersistentHashSet. So, the fact that it works at all in Clojurescript seems to be a bug as well. On Aug 15, 1:13 am, Meikel Brandmeyer (kotarak) m...@kotka.de wrote: Hi, Am Sonntag, 14. August 2011 18:59:57 UTC+2 schrieb Despite: In Clojurescript, calling rand-nth on an empty Set results in an Index out of bounds exception, whereas calling it on an empty Vector results in nil. Returning nil for vectors is almost certainly a bug as it should throw an exception according to the docstring of nth. Sincerely Meikel -- 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
Exception calling nth on Sets
In Clojurescript, calling rand-nth on an empty Set results in an Index out of bounds exception, whereas calling it on an empty Vector results in nil. ClojureScript:cljs.user (rand-nth (set [])) Error evaluating: (cljs.core.prn (rand-nth (set []))) :as cljs.core.prn.call(null,cljs.core.rand_nth.call(null,cljs.core.set.call(null,cljs.core.Vector.fromArray([]; \nsun.org.mozilla.javascript.internal.JavaScriptException: Index out of bounds (cljs/core.cljs#937) ClojureScript:cljs.user (rand-nth (vec [])) nil Drilling down, the problem is that calling nth with an out-of-range index returns nil for Vectors, but throws that exception for Sets. But, using the set as a function, you do get nil: ClojureScript:cljs.user ((set [1 2 3]) 10) nil Am I doing something wrong? Or is there a bug in how nth is defined for Sets? -- 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
Re: Exception calling nth on Sets
My guess is that nth (and by extension rand-nth) can't implicitly call seq on the collection because if it did, you'd lose the fast access that vectors provide. So you'll need to call seq on your set before passing it to rand-nth. -- 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
