flatten has been discussed before: https://groups.google.com/forum/?fromgroups=#!topic/clojure/ye70iNJ73zc
See also CLJ-400, but it looks like no patch was submitted. http://dev.clojure.org/jira/browse/CLJ-400 I think the general policy for Clojure is that the core functions of course should work as documented, but they do not necessarily handle undocumented edge cases. So if you use the wrong kinds of arguments, the implementation does not have to detect your error -- it might throw or just give you non-useful results. There's a trade-off among ease of implementation, performance and programmer friendliness. If it's a common mistake, maybe an assertion is warranted. If I remember correctly, Rich Hickey suggested that someday there might be an option to run a stricter version of Clojure (with lots of assertions) during development, and a faster version with less checking in production. Regarding flatten in particular, I would like it to be faster and to do a bit more to help the careless programmer. I was all set to submit a patch condemning the elegant but slow implementation when I noticed that the new "reducers" version of flatten in 1.5 alphas is amazingly fast. So that looks like the way to go. On Aug 29, 2012, at 3:47 PM, dmirylenka <daniilmirile...@gmail.com> wrote: > Calling flatten on anything that is not 'sequential?' returns an empty > sequence: > > (flatten 1); => () > (flatten "Hi"); => () > > With sets if feels somewhat strange: > > (flatten #{#{:a} #{:b :c}}); => () > > For some reason I expected #{#{:a} #{:b :c}} to equal #{:a :b :c}. > > Ok, the docstring says: "Takes any nested combination of sequential > things...", and sets are not sequential... > > But then, why > > (reduce + (flatten #{1 2})); => 0 > (r/reduce + (r/flatten #{1 2})); => 3 ? -- 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
