Thank you for this info and the suggestion! David On Tue, 14 Mar 2017 at 09:06, Martin Maechler <maech...@stat.math.ethz.ch> wrote:
> >>>>> David Hugh-Jones <davidhughjo...@gmail.com> > >>>>> on Tue, 14 Mar 2017 02:46:35 +0000 writes: > >>>>> David Hugh-Jones <davidhughjo...@gmail.com> > >>>>> on Tue, 14 Mar 2017 02:46:35 +0000 writes: > > > Hi, > > Cross-posted from SO: > > > http://stackoverflow.com/questions/42776058/extending-an-s3-generic-from-an-optional-package > > ((sent my answer there as well)) > > > I have a package which provides an as.FlexTable method for its > objects, > > extending the S3 generic from the ReporteRs package. So, my > NAMESPACE file, > > generated by roxygen, has lines: > > > importFrom(ReporteRs,as.FlexTable) > > ... > > S3method(as.FlexTable,huxtable) > > ... > > export(as.FlexTable) > > > I don't much want to put ReporteRs in Imports: in the DESCRIPTION > file, > > because it involves a big external dependency on Java. But, when I > put it > > into Suggests:, R CMD check gives me errors like "Namespace > dependency not > > required". > > > Is there anyway I can extend the generic without making a hard > dependency? > > No. Importing is a hard dependency.. > Some people do not import formally but use '<pkgNamespace>::<obj>' > instead, *and* conditionalize their code on the availability of > that namespace. > I don't recommend that at all, and particularly not for > extending a generic. > > I recommend you talk with the maintainer of 'ReporteRs': > 1) You could use a common (yet-to-create) very small package say > 'flexS3generics' > which provides S3 generics (and S4 if ..) you want to use > both, and then both you and her/him import from that mini package. > You'd be both authors of that package. > > 2) If your package is much smaller (in its footprint, incl > dependencies) than 'ReporteRs' she/he may agree to import the > S3 generic from your package instead of the other way around. > > Both are clean solutions, > and both need some time-coordination when releasing to CRAN, > '1)' being easier: Once the 'flexS3generics' is released to > CRAN, change (both) your package(s) to > importFrom(flexS3generics,*) but these changes and CRAN > submissions are then independent of each other. > > > > Cheers, > > David > > -- Sent from Gmail Mobile [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
