>> In fact, the way that count works on ISeqs is rather roundabout -- it only works because all implementations of ISeq in clojure.jar also happen to implement java.util.List, so count calls Collection.size(). In theory, some user-provided ISeq which didn't implement List would not respond to count.
------ That is just completely untrue: https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/RT.java#L536 https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj#L826 Timothy On Mon, May 13, 2013 at 10:17 AM, Philip Potter <philip.g.pot...@gmail.com>wrote: > In fact, the way that count works on ISeqs is rather roundabout -- it > only works because all implementations of ISeq in clojure.jar also > happen to implement java.util.List, so count calls Collection.size(). > In theory, some user-provided ISeq which didn't implement List would > not respond to count. > > It's probably a good idea for interop reasons to have seqs implement > the java collection types, but I don't feel too happy about clojure > code which uses the java Collection interface on seqs. > > Phil > > On 13 May 2013 15:48, Meikel Brandmeyer (kotarak) <m...@kotka.de> wrote: > > Hi, > > > > Am Montag, 13. Mai 2013 16:16:57 UTC+2 schrieb Sean Corfield: > >> > >> > >> So you think (count (map inc [1 2 3])) should be illegal? > >> > >> (I'm just trying to understand your logic here) > >> > > > > In the hardcore version, yes. In the practical version, probably not. I > > never had to call count on a seq. (Various versions of partition-by or > split > > being a notable exception.) (Still a promised O(1) count would be nice > for > > reasoning as we have it for contains?. What is clojure.lang.Counted good > for > > anyway?) > > > > 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 > > --- > > 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/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 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/groups/opt_out. > > > -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- -- 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/groups/opt_out.
