"Janko Thyson" <janko.thyson.rst...@googlemail.com> writes:
>> I'm experimenting with a few model-fitting classes of my own. I'm >> leaning towards using S4 for my classes, but the R functions I'd want >> to override (residuals, predict, etc.) are all S3 methods. > For example, inside your method for 'residuals()', you will > probably just get some data out of a slot of your object and run the S3 > function 'residuals(your.slot.data)'. So there's nothing that should make > you nervous in that respect, you're not overwriting anything with your > method. Setting a generic for an existing function is just a necessary step > in order to specify S4 methods for it. Yes, I understand that it's a necessary step in R, but I'm still puzzled as to why it's necessary. (And by "why", I don't mean the technical point that 'residuals' is not an S4 generic function; I mean why isn't it a S4 generic function already?) In principle, R could be shipped with all S3 functions replaced by S4 functions that default to the S3 implementation. That would be a benefit to everyone writing S4 objects. The fact that it's not been done seems to imply it would have a cost to people writing S3 objects, so I'm trying to understand what that cost is. Perhaps I'm seeing an implied risk where I really should be seeing a loose federation of developers with disparate interests, and the slow pace of "global" change that implies. Thanks, Johann ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
