Good call on the auto-boxing. I wasn't considering that before, but obviously it is important.
Nice insight into :inline. I never really did understand the usefulness of it before. On Tuesday, July 7, 2015 at 10:20:51 PM UTC-5, Herwig Hochleitner wrote: > > 2015-07-07 15:04 GMT+02:00 Jo Geraerts <j...@umask.net <javascript:>>: >> >> * multiply(long x) >> * multiply(double x) >> * multiply(Number x) >> >> In clojure i want to do something like >> >> (defn multiply[^MonetaryAmount amount multiplicant] >> (.multiply amount multiplicant)) >> > > Function parameters in Clojure, are generally passed as a > java.lang.Object, so numbers are boxed by default. > Clojure does have infrastructure to pass primitive numbers, see invokePrim > here: > https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/IFn.java#L97 > > see also http://clojure.org/java_interop#Java Interop-Support for Java > Primitives > however, this requires a specific type hint on the multiply fn, so > normally that means separate multiply-double and multiply-long fns. > > The way I would do it: Define multiply as a function calling (.multiply > amount ^Number x), for higher order usage, and then add an :inline function > to its metadata, which returns `(.multiply ~amount ~x). > That acts as a compiler macro, which inlines the call to .multiply, that > way, its parameter type can be assigned via local type inferrence (which > clojure does). > See http://www.bytopia.org/2014/07/07/inline-functions-in-clojure/#sec-3 > Beware, that inline functions aren't public API and subject to change. > > kind regards > -- 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/d/optout.
