Calling seq on vector returns a sequence which is no longer a vector. The docstring is pretty specific about which types it's supposed to work on.
clojure.core/peek ([coll]) For a list or queue, same as first, for a vector, same as, but much more efficient than, last. If the collection is empty, returns nil. David On Thu, Jun 20, 2013 at 4:11 PM, Jason Gilman <[email protected]>wrote: > Also, I really appreciate anyone who takes the time to answer. My company > is currently evaluating Clojure. I'm trying to determine if this is > non-idiomatic use of the language or some other issue. Doing something like > this can cause the bug to occur without directly calling seq on a vector: > > (defn bar [my-list n] > (if (= n 0) > (peek my-list) > (bar (rest my-list) (dec n)))) > (bar [1 2 3] 1) > > Both rest and peek work on a vector without a problem but the combination > of the two causes problems. > > On Thursday, June 20, 2013 3:54:43 PM UTC-4, Jason Gilman wrote: >> >> Why does (peek (seq [1])) result in: >> ClassCastException clojure.lang.PersistentVector$**ChunkedSeq cannot be >> cast to clojure.lang.IPersistentStack clojure.lang.RT.peek (RT.java:634) >> >> Peek documentation "For a list or queue, same as first, for a vector, >> same as, but much more efficient than, last. If the collection is empty, >> returns nil." implies that there shouldn't be a problem working with >> vectors. >> >> This works without issue: >> (peek [1]) >> >> This is on Clojure 1.5.1 >> > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to [email protected] > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > [email protected] > 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 [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] 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 [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
