Dear r-devel, options() are basically global variables and they come with several issues: * they're not really truly owned by a package aside from loose naming conventions * they're not validated * their documentation is not standard, and they're often not documented at all, it's hard to know what options exist * in practice they're sometimes used for internal purposes, which is at odds with their global nature and contribute to the mess, I think they can almost always be replaced by objects under a `globals` environment in the namespace, it's just a bit more work
I tried to do as much as possible with static analysis using my package opt but it can only go so far : https://github.com/moodymudskipper/opt I think we can do a bit better and that it's not necessarily so complex, here's a draft of possible design : We could have something like this in a package to register options along with an optional validator, triggered on `options(..)` (or a new function). # similar to registerS3method() : registerOption("mypkg.my_option1") registerOption("mypkg.my_option2", function(x) stopifnot(is.numeric(x)) # maybe a `default` arg too to avoid the .onLoad() gymnastics and invisible NULL options * validation is a breaking change so we'd have an environment variable to opt in * validation occurs when an option is set AND the namespace is already loaded (so we can still set options without loading a namespace) OR it occurs later when an applicable namespace is loaded * if we register an option that has already been registered by another package, we get a message, the validator of the last loaded namespace is used, in practice due to naming conventions it doesn't really happen, CRAN could also enforce naming conventions for new packages * New packages must use registerOption() if they define options, and there must be a standard documentation page for those, separately or together (with aliases), accessible with `?mypkg.my_option1` etc... This could certainly be done in different ways and I'd love to hear about other ideas or obstacles to improvements in this area. Thanks, Antoine [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
