A good implementation of ISeq won't return a new object, and new short-lived objects are cheap on the JVM anyway. OTOH count can be slow for some data structures. if you don't like instantiating lots of new objects only to throw them away, you're missing out on one of HotSpot's most significant performance/convenience sweet spots, so it's strange you call that premature optimization.
There is however an optimization story against seq: Hotspot (at least on my machine) refuses to inline the call to seq by default (it might still inline if the stars are right or something, the JVM is mysterious). My guess is it's because the code in seq and seqFrom is too big, on my box it exceeds the inline threshold by one byte... On Monday, May 13, 2013 1:32:09 AM UTC-5, Meikel Brandmeyer (kotarak) wrote: > > Hi, > > Am Samstag, 11. Mai 2013 21:25:11 UTC+2 schrieb Alex Baranosky: >> >> Most of the code I see and write at work at Runa uses (not (empty? foo)). >> I'll continue to defend the position that it is more obvious code, and >> therefore better (imo :) ) >> >> > seq belongs to seq-land. empty? belongs to data structure land. It should > actually be implemented as #(zero? (count %)). But unfortunately it is not. > Maybe I'm to green (and too much a premature optimiser) , but I don't like > allocating and initialising a new object just to throw it away immediately. > > 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.
