I think this would be a good change. I think most users use the 'methods(class = <...>)' function to answer the question, "what methods can I call on objects with these classes?", and in that context I think it would be sensible for the function to accept more than one class.
Kevin On Wed, Oct 17, 2018 at 7:15 AM Martin Maechler <maech...@stat.math.ethz.ch> wrote: > > With new "strict" settings in R-devel, the following glm() example > > > data(anorexia, package = "MASS") > > fm <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian, data = > > anorexia) > > methods(class = class(fm)) > Warning in grep(name, row.names(info)) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in gsub(name, "", row.names(info)) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in grep(pattern, all.names, value = TRUE) : > argument 'pattern' has length > 1 and only the first element will be used > Warning in grep(pattern, all.names, value = TRUE) : > argument 'pattern' has length > 1 and only the first element will be used > ........... > ........... > ........... > [ca. 20 lines of warnings] > > and then shows the "glm" methods, but not "lm" ones. > > This is not a bug strictly, as ?methods says that > > class: a symbol or character string naming a class: only used if > ‘generic.function’ is not supplied. > > and so the use of > > methods(class = class(<obj>)) > > is a user error when class(<obj>) is of length > 1. > > In the case of e.g. a randomForest() result, we also get 25 > warnings, i.e. 50 lines, but then > > --->>> no methods found > > because > > > class(rf.fit) > [1] "randomForest.formula" "randomForest" > > and no methods are defined for "randomForest.formula". > > --- > > Of course, all this works fine with S4 classes: There the full > inheritance is used and all methods are found. > > Still, would it make sense to improve the underlying .S3methods() ? > > I assume it will break *some* overzealous package checks out > there when .S3methods() and hence methods() would return *more* > in such case. > > Comments? > > -- > Martin Maechler > ETH Zurich and R Core > > ______________________________________________ > 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
