On Mon, 7 Jan 2008, Robin Hankin wrote: > I am writing a package and need to decide whether to use S3 or S4. > > I have a single class, "multipol"; this needs methods for "[" and "[<-" > and I also need a print (or show) method and methods for arithmetic +- > */^. > > In S4, an object of class "multipol" has one slot that holds an array. > > Objects of class "multipol" require specific arithmetic operations; > a,b being > multipols means that a+b and a*b are defined in peculiar ways > that make sense in the context of the package. I can also add and > multiply > by scalars (vectors of length one). > > My impression is that S3 is perfectly adequate for this task, although > I've not yet finalized the coding. > > S4 seems to be "overkill" for such a simple system. > > Can anyone give me some motivation for persisting with S4? > > Or indeed reassure me that S3 is a good design decision?
Does performance matter?: S4 dispatch is many times slower than S3 dispatch for such functions. (It is several times slower in general, but the difference is particularly marked for primitives.) -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
