On Thu, 2012-03-29 at 23:31 -0700, Benjamin Peter wrote: > the sequence would have been traversed completely by the reduce call > and therefore clojure could know it's size and provide a constant time > count. > > Could this be implemented?
Yes. You could probably implement it yourself, as a wrapper sequence type, though this wouldn't make all other sequence types automatically countable. > Is it? It won't be, in general, because you would have to "hold onto the head" until you got to the end, or go through a costly half-broken weak reference dance. It is worth considering that even for some uncounted sequences, the cost of a second traversal for "count" may be less than the bookkeeping cost of keeping a count as you traverse once. -- Stephen Compall ^aCollection allSatisfy: [:each|aCondition]: less is better -- 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
