[Rd] S3 methods in default namespace
murdoch.duncan at gmail.com
Mon Aug 29 14:40:53 CEST 2011
On 29/08/2011 8:20 AM, Hadley Wickham wrote:
> >> So doesn't that break packages that use S3 but don't have a NAMESPACE?
> > Maybe, but since the methods are exported as functions they are also found
> > for method dispatch and imported, if another package imports from the
> > Namspace. The problem I see is what happens if method dispatch is done on a
> > package that is not attached but just the Namespace is only loaded.
> > Anyway, we should really recommend that package authors write NAMESPACE
> > files in case their packages are not trivial.
> > Note that there are many CRAN packages that fail under R-devel, some of them
> > sue to NAMESPACE issues.
> I'm not sure I understand the approach of providing a default
> NAMESPACE. Why not just make it a requirement to pass R CMD check?
> That seems like it would be a safer approach, although it would create
> some work for people who have not yet started using namespaces.
About 1000 packages on CRAN didn't have a NAMESPACE file. Most of them
were very simple so our default NAMESPACE is sufficient. Some of them
were not so simple, and those ones really need to have a NAMESPACE.
Adding the namespace makes all of the packages more predictable and
reliable (because it gives a defined search order for functions), but
there's no point forcing 1000 package authors to do it if it can be done
automatically. However, there are at least a few dozen who should have
done it long ago, and those ones will need to do it to pass checks.
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