That sounds about right. See https://github.com/clojure/clojure/blob/41af6b24dd5be8bd62dc2b463bc53b55e18cd1e5/src/jvm/clojure/lang/Counted.java
On Tue, Aug 4, 2015 at 11:06 AM, Gary Verhaegen <gary.verhae...@gmail.com> wrote: > I don't know of it is correct, but I also remember reading that Counted > was a "marker interface", i.e. it does not actually add any method but it > implies that the count operation will be "fast". > > > On Tuesday, 4 August 2015, Laurent PETIT <laurent.pe...@gmail.com> wrote: > >> If I'm remember correctly, the Counted interface must only be implemented >> by collection implementations for which it is guaranteed that count() is an >> O(~1) operation >> >> 2015-08-04 17:07 GMT+02:00 Keisuke Fukuda <keisukefuk...@gmail.com>: >> >>> Hello, >>> >>> I've been investigating the basic data structures and their underlying >>> concepts in Clojure, particularly focusing on the definitions of coll, seq, >>> map, vector, set, etc. and their inclusion relationships. >>> >>> I saw a Venn diagram in this page[1]. Although it is as of Clojure 1.3, >>> I confirmed it is still correct. "Counted" interface has its only method >>> count() and it implies that we can get the explicit size of a "Counted" >>> collection. >>> >>> However, IPersistentCollection, which is actually the definition of >>> collections, also has count() method. It's a bit surprising to me that even >>> LazySeq supports count() (indirectly via ISeq). >>> >>> Questions: >>> If IPersistentCollection has count() method, What is "Counted" for? >>> Is it always reasonable for LazySeq to support count() method? Shouldn't >>> there be an explicit "CountedLazySeq", >>> >>> Thanks. >>> Keisuke >>> >>> [1] http://www.brainonfire.net/files/seqs-and-colls/main.html >>> >>> >>> -- >>> FUKUDA, Keisuke <福田圭祐> >>> Tokyo, Japan >>> Email: keisukefuk...@gmail.com >>> >>> -- >>> 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. >>> >> >> >> >> -- >> Laurent Petit >> >> -- >> 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. >> > -- > 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. > -- 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.
