=> (pop '(1 2 3)) (2 3) => (pop (seq '(1 2 3))) (2 3) => ((fn [& xs] (pop xs)) '(1 2 3)) ClassCastException clojure.lang.ArraySeq cannot be cast to clojure.lang.IPersistentStack => (pop (map inc (take 5 (iterate inc 0)))) ClassCastException clojure.lang.LazySeq cannot be cast to clojure.lang.IPersistentStack
That's not right. Pop should act the same as next on all seqs. Instead it seems to care about details of how the seq was obtained. This clearly violates least surprise. Even wrapping in seq doesn't save you: => (pop (seq (map inc (take 5 (iterate inc 0))))) ClassCastException clojure.lang.Cons cannot be cast to clojure.lang.IPersistentStack This despite (pop (seq '(1 2 3))) working. It *definitely* should be the case that either (pop (seq x)) works for all non-empty x, or (pop (seq x)) fails for all non-empty x! The obvious fix is to make Cons, LazySeq, ArraySeq, and possibly other concrete seq/list-type objects that do not already do so implement IPersistentStack, with peek and pop invoking first and next, respectively. -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
