>>>> "MM" == Martin Morgan <mtmor...@fhcrc.org> >>>> on Tue, 18 Aug 2009 06:15:50 -0700
Hi Martin, Thanks for your response. MM> Commenting as a user, there's no guarantee that the 'plot' MM> generic MM> defined in pkgA is derived from graphics::plot via setGeneric; MM> pkgA MM> could define it's own generic, and one would want to be informed MM> of the MM> collision. This shouldn't be a problem because generics keep track of the function and package used. setGeneric(plot) str(getGeneric(plot)) MM> MM> Maintenance of packages that have used simple 'import' to pull MM> in all MM> dependencies is tedious, but using 'import' in some ways MM> undermines MM> benefits of name spaces (restricting the symbol lookup table MM> to reduce MM> the number of symbols and the possibility of name collisions, MM> and to MM> more carefully isolate code inside the package name space to MM> changes in MM> imported packages or induced by the user). So I think a 'better MM> practice' is to explicitly import just those functions, MM> classes, etc MM> that are required by the package. Maintenance of such selective MM> imports MM> is much less tedious, even with complicated package MM> dependencies. There MM> is an unreleased Bioconductor package to identify specific MM> imports, MM> available for R-2.9.* at I agree with you that 'importFrom' should be the preferred approach. I have been using it for some time and I have even wrote my own functions to automatically generate the NAMESPACE. But the drawback is that it makes the dependency with other packages version specific and can become tricky when one has several such dependencies. To make the maintenance of packages easier, I would like to use the suboptimal 'import' so that I do not need to care about this NAMESPACE/package version issue. But I cannot do that because of an, IMO, unjustified warning. regards, Yohan -- PhD student Swiss Federal Institute of Technology Zurich www.ethz.ch ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
