On Thu, 2009-12-03 at 14:25 -0800, John Chambers wrote: > I missed the earlier round of this discussion and only am commenting > now to say that this doesn't seem weird at all, if I understand what > you're trying to do. > > Martin's basic suggestion, > v <- callGeneric(e1, as(e2, "A")) > seems the simplest solution. > > You just want to make another call to the actual generic function, > with new arguments, and let method selection take place. In fact, > it's pretty much the standard way to use group generics. > > John There were 2 weird parts. Mainly I was referring to the fact that identical code (posted earlier) worked sometimes and not others. I could not figure out what the differences were between the 2 scenarios, nor could I create a non-working scenario reliably.
The second part that seemed weird was that the code looked as if it should work all the time (the last full version I posted, which used callNextMethod() rather than callGeneric()). Finally, I felt somewhat at sea with the group generics, since I wasn't sure exactly how they worked, how they interacted with primitives, or how they interacted with callNextMethod, selectMethod, etc. I did study what I thought were the relevant help entries. Ross > > > Ross Boylan wrote: > > Thanks for your help. I had two concerns about using as: that it would > > impose some overhead, and that it would require me to code an explicit > > conversion function. I see now that the latter is not true; I don't > > know if the overhead makes much difference. > > > > On Thu, 2009-12-03 at 13:00 -0800, Martin Morgan wrote: > > > > > setMethod("Arith", signature(e1="numeric", e2="B"), function(e1, e2) { > > > new("B", xb=e1...@xb, callGeneric(e1, as(e2, "A"))) > > > }) > > > > > > > Things were getting too weird, so I punted and used explicitly named > > function calls for the multiplication operation that was causing > > trouble. > > > > Ross > > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > > > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel