On Nov 6, 2012, at 2:44 PM, Davor Cubranic wrote: > On 2012-11-06, at 9:49 AM, Uwe Ligges wrote: > >> On 06.11.2012 17:55, Christophe Genolini wrote: >>> >>>> "Imports" means that symbols are imported form the namespace, so they >>>> are mandatory for the package to operate. "Suggests" means that >>>> symbols from the package are not required, but they are used in >>>> examples or vignettes, so the listed package(s) will be needed for a >>>> full check. They are not needed for the operation of the package, though. >>> That's very clear, thanks a lot. >>> So I will use >>> >>> >>> - 'Depends:foo1' if there is a function in foo1 that my package use often >> >> No, better make use of Namespace imports all the time and only use "Depends" >> if you really need the other package to be installed. This is rarely needed. > > Uwe, did you mean to say "only use 'Depends' if the other package really > needs to be *attached*"?
I think so. BTW: this Depends/Imports is an interesting aspect that it may look trivial for package developers, but can be quite confusing for users. Uwe was suggesting Imports over Depends which is clean from a technical point of view (no namespace collisions etc.), but as an R user I have to say I find it bad since I used to be able to just load one package and not have to load (=attach) every package in the dependency tree that I may want to use myself by hand, but if people really decide to go that route, you'll have to do it for every single package which is a real pain. (Also it's a very bad thing for debugging - you can't even ask users to test things since the imports will be hidden). In addition, it hides declared methods which is, again, a pain when using R interactively, since you can't simply check what a certain method definition looks like - you'd have to hunt for it through namespaces (this is also related to not exporting methods). There is a difference in treating R as ! a scripting language versus an interactive analytics system and I find that recently focus has been shifting to the former aspect, while, personally, I think it's actually more useful as the latter. (Just my $0.02 off topic ;)) Cheers, Simon > Because in terms of determining dependencies for `install.package`, I thought > "Imports" and "Depends" are no different. (Unless the user explicitly chooses > otherwise in the 'dependencies' argument, that is.) > >>> - 'Imports:foo2' if there is a function in foo2 that my package might >>> use rarely > > > I don't think choosing to declare "Imports" has anything to do with frequency > of use. But if you do use it, then don't forget to include "imports(foo2)" or > "importsFrom(foo2, ...)" in the NAMESPACE file. > > Davor > > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
