Re: chunked-seq? is lying?
On Dec 31, 2010, at 5:53 PM, Mike K wrote: > OK, I understand the difference in behavior between the two maps. But > why is chunked-seq? incorrect? > > Also, Chas Emerick stated in another discussion that ranges always > produce chunked seqs, but the value of (chunked-seq? (range 100)) > seems to belie that. I was being a little loose in my description. Ranges always produce chunked seqs via seq: => (chunked-seq? (range 10)) false => (chunked-seq? (seq (range 10))) true `range` returns a lazy seq, which "guards" the chunked seq. Lazy seqs are never chunked themselves (otherwise, "proper" laziness would never be possible) but the seqs they provide are always aligned with the chunkiness of whatever lies beneath the lazy seq: => (chunked-seq? (seq (lazy-seq '(1 2 3 false => (chunked-seq? (seq (lazy-seq [1 2 3]))) true - Chas -- 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
Re: chunked-seq? is lying?
OK, I understand the difference in behavior between the two maps. But why is chunked-seq? incorrect? user> (take 1 (map #(do (print ".") [%]) (range 100))) ([0]) user> (chunked-seq? (range 100)) false user> (chunked-seq? (map #(do (print ".") [%]) (range 100))) false user> (chunked-seq? (take 1 (map #(do (print ".") [%]) (range 100 false The implementation of chunked-seq? checks to see if the sequence is an instance of clojure.lang.IChunkedSeq. That doesn't appear to be sufficient in the case of map taking one collection. Also, Chas Emerick stated in another discussion that ranges always produce chunked seqs, but the value of (chunked-seq? (range 100)) seems to belie that. Mike -- 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
Re: chunked-seq? is lying?
Hi, Am 31.12.2010 um 19:57 schrieb Mike K: > In 1.2, I don't understand why one of the sequences below is chunked, > but the other is not. Also, chunked-seq? seems to be lying about the > second one. > > user> (take 1 (map #(do (print ".") [% %2]) (range 100) (range 100))) > (.[0 0]) > user> (take 1 (map #(do (print ".") [%]) (range 100))) > ([0]) > user> (chunked-seq? (map #(do (print ".") [%]) (range 100))) > false For map with multiple input sequences all sequences would probably be have to be chunked with the same chunk size. So instead of checking this, map produces for multiple input sequences a non-chunked seq. Sincerely 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
chunked-seq? is lying?
In 1.2, I don't understand why one of the sequences below is chunked, but the other is not. Also, chunked-seq? seems to be lying about the second one. user> (take 1 (map #(do (print ".") [% %2]) (range 100) (range 100))) (.[0 0]) user> (take 1 (map #(do (print ".") [%]) (range 100))) ([0]) user> (chunked-seq? (map #(do (print ".") [%]) (range 100))) false Mike -- 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
