>>>>> <mark.braving...@csiro.au> >>>>> on Wed, 25 Aug 2010 14:06:07 +1000 writes:
> I recently moved a function 'subset.with.warning' into the 'mvbutils' package (a version not yet on CRAN). When I tried RCMD CHECK, I got this warning: > * checking S3 generic/method consistency ... WARNING > subset: > function(x, ...) > subset.with.warning: > function(x, cond, mess.head, mess.cond, row.info, sub) > See section 'Generic functions and methods' of the 'Writing R Extensions' > manual. > I know that S3 method arguments need to be compatible with arguments of the generic. However, 'subset.with.warning' is deliberately not a registered S3 method, I think that's your real trouble ... and then your users' if you really insist. Short answer: "Don't do that!" There have been a few exceptions of "100 years old" R functions which validated this rule, the most notable probably t() and t.test(), and we (R core) have explicitly listed them in the code base as "yes, looks like a method for an S3 generic, but not it ain't!", but have basically "forbidden" to commit more such crimes. {Also, if you are interested: I think both t() and t.test() pre-dated S3} > and its USAGE section doesn't include a \method{generic}{class} statement. I couldn't see anything in "R Extensions" that says "don't do this", so I'm wondering: Yes, we should add a such "don't do this" somewhere. Can you propose a good place to put it in there? > - should this really be a NOTE not a WARNING (or nothing at all)? {from the above: definitely a warning, if not "worse"}.... Best regards, Martin Martin Maechler, ETH Zurich > - if not, shouldn't there be a more explicit statement to the effect that "if R decides it's a method, then it damned well is a method, whether you think it is or not"? > - and if so, should there also be a check for functions that look like methods but aren't registered and declared as such? > My preference would be for the first, FWIW. Admittedly, just because I didn't register 'subset.with.warning' as an S3 method, that won't stop 'subset' from trying to use it if it ever encounters an object of class "with.warning". It's a risk that I'm happy to take, though CRAN might not be... > I made the warning go away by adding a '...' argument to the end of 'subset.with.warning', but that's not pretty. > Mark Bravington > CSIRO > Hobart > Australia >> sessionInfo() > R version 2.11.1 Patched (2010-06-30 r52418) > i386-pc-mingw32 > locale: > [1] LC_COLLATE=English_Australia.1252 LC_CTYPE=English_Australia.1252 LC_MONETARY=English_Australia.1252 LC_NUMERIC=C > [5] LC_TIME=English_Australia.1252 > attached base packages: > [1] grDevices tools tcltk stats graphics utils methods base > other attached packages: > [1] ad_1.0 chstuff_1.0 handy2_1.2 tweedie_2.0.2 statmod_1.4.1 handy_1.1 debug_1.2.3 mvbutils_2.5.2 >> > ______________________________________________ > 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