We use this technique in a couple of places: https://github.com/tidyverse/dbplyr/blob/6be777d8b23d588f19c98de52f4e58f16c2ef67e/R/zzz.R
Basic idea is to call registerS3method() manually, when needed - it's just a little tricky because the suggested package may be loaded either before or after your package. Hadley On Thu, Dec 7, 2017 at 1:45 AM, Joshua Ulrich <josh.m.ulr...@gmail.com> wrote: > I have a feeling I know the answer to this question, but I'm asking > with the hope that I learn something new. > > Package A defines a S3 generic function, "foo()". Package B defines a > S3 class "bar", and a foo.bar() method. This method is not strictly > necessary for the package to function, and package A has many > dependencies. > > To avoid excessive dependencies, I would like to only register > foo.bar() if package A is installed at the time package B is > installed. If package A is installed after package B, then warn the > user when package B is loaded and/or attached, so they can re-install > A and have foo.bar() registered correctly. > > I could figure out a way to do this manually, but doubt it would be > CRAN-approved. What is the recommended way to handle this situation? > I've received one suggestion to split B into 2 packages: one without > the method, and one with. Are there other alternatives? > > Thanks, > Josh > > -- > Joshua Ulrich | about.me/joshuaulrich > FOSS Trading | www.fosstrading.com > R/Finance 2018 | www.rinfinance.com > > ______________________________________________ > R-package-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-package-devel -- http://hadley.nz ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
