Howard Lewis Ship a écrit : > I have to wonder a bit about the ability to optimize. Everything > boils down to one of the seven or so basic forms. That's a lot of > function calls to do even small things, like adding numbers. You might > think that simple math would be optimized and inlined, but it isn't: > > Clojure > user=> (doc +) > ------------------------- > clojure.core/+ > ([] [x] [x y] [x y & more]) > Returns the sum of nums. (+) returns 0. > nil > user=> (ns clojure.core) > #<Namespace clojure.core> > clojure.core=> (defn + [x y] (* x y)) > #'clojure.core/+ > clojure.core=> (+ 3 5) > 15 > clojure.core=> > > This implies, to me, that Clojure is doing a full functional call, > with dynamic lookup via the namespace, even for +. To me, this means > that Clojure will never be as fast as Java code *when implementing the > same algorithm*. Clojure will be faster when taking advantage of > laziness and concurrency and that's fine by me. >
Not quite. + (and al.) gets special treatment, it is inlined: clojure.core=> (defn add [x y] (+ x y)) #'clojure.core/add clojure.core=> (defn + [x y] (* x y)) #'clojure.core/+ clojure.core=> (+ 3 5) 15 clojure.core=> (add 3 5) 8 This allows, in a tight loop, the jit to emit code as fast as equivalent java code. Christophe -- Professional: http://cgrand.net/ (fr) On Clojure: http://clj-me.blogspot.com/ (en) --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
