2009/11/2 Jochen Theodorou <[email protected]>: > > John Wilson schrieb: > [...] >> It's virtually impossible to do effective type inferencing with Groovy >> semantics. E.G. with >> >> int a = 1 >> int b = 2 >> def x = a + b > > I can assume x is int. But I am not free in assuming that the plus > method is really hat I assume and that x will get the right type. So I > need alternate paths.
No, you can't assume x is int. For example, it's perfectly reasonable to override the arithmetic operations to return long if the operation would otherwise overflow. There is nothing in the Groovy language that says that the result of adding two ints is an int (or at least there wasn't a couple of yeas ago - has that changed?). > > [...] >> I have never seen any way of doing unguarded direct method calls in >> Groovy. It is possible to generate synthetic helper methods on a >> compiled Groovy class which can be safely called directly but these >> helper methods need to do checks before they can pass the call on to >> the target method; so you are, in effect, doing guarded calls. > > yes. I don't intend to change the semantics of Groovy in that area, so > every call is guarded in some way. But how guarding is done is important > too. > > [...] >> Still, Jochen has been thinking about this for longer than I have - so >> maybe he's seen something I've missed. > > I found out the guarding itself is not so bad. hotspot can remove many > of those checks. The important part here is that the guards are in the > call site or else it is very fast anything but monomorphic. Yes, Hotspot can be pretty good at optimising out guards. My experience is that they don't actually have to be at the call site - Hotspot inlines code quite readily so if you put it in a helper method it gets inlined quite quickly and then treated in the same way as if it was generated at the call site. John Wilson --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "JVM Languages" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jvm-languages?hl=en -~----------~----~----~----~------~----~------~--~---
