On 28/08/2013 2:50 PM, Paul Gilbert wrote:
On 13-08-28 12:29 PM, Marc Schwartz wrote:
>
> On Aug 28, 2013, at 11:15 AM, Paul Gilbert <pgilbert...@gmail.com> wrote:
>
>> I have a package (TSdbi) which provides end user functions that I export,
and several utilities for plugin packages (e.g. TSMySQL) that I do not export because
I do not intend them to be exposed to end users. I call these from the plugin
packages using TSdbi::: but that now produces a note in the checks:
>>
>> * checking dependencies in R code ... NOTE
>> Namespace imported from by a ‘:::’ call: ‘TSdbi’
>> See the note in ?`:::` about the use of this operator. :: should be
>> used rather than ::: if the function is exported, and a package
>> almost never needs to use ::: for its own functions.
>>
>> Is there a preferred method to accomplish this in a way that does not
produce a note?
>>
>> Thanks,
>> Paul
>
>
>
> Paul,
>
> See this rather lengthy discussion that occurred within the past week:
>
> https://stat.ethz.ch/pipermail/r-devel/2013-August/067180.html
>
> Regards,
>
> Marc Schwartz
I did follow the recent discussion, but no one answered the question "Is
there a preferred method to accomplish this?" (I suppose the answer is
that there is no other way, given that no one actually suggested
anything else.) Most of the on topic discussion in that thread was about
how to subvert the CRAN checks, which is not what I am trying to do and
was also pointed out as a bad idea by Duncan. The substantive response was
>r63654 has fixed this particular issue, and R-devel will no longer
>warn against the use of ::: on packages of the same maintainer.
>
>Regards,
>Yihui
but that strikes me as a temporary work around rather than a real
solution: suppose plugins are provided by a package from another maintainer.
Since CRAN notes have a habit of becoming warnings and then errors, it
seems useful to identify the preferred legitimate approach while this is
still a note. That would save work for both package developers and CRAN
maintainers.
My thinking is that there is a need for a NAMESPACE directive something
like limitedExport() that allows ::: for identified functions without
provoking a CRAN complaint when packages use those functions. But there
may already be a better way I don't know about. Or perhaps the solution
is to split the end user functions and the utilities for plugin packages
into two separate packages?
I don't see a need for that. The reason ::: is bad is because
non-exported functions may change without notice, breaking the package
that uses them, and possibly giving the users of that package bad
results. If you're the maintainer of both the donor and user of the
non-exported function, then you can be expected to keep them in sync,
hence r63654. If those are different people, then the donor had better
indicate that the function is safe to use. That's what export() does.
If you are worried about a cluttered listing of functions and help
pages, you can use an initial "." in the name of the object, or use
\keyword{internal} in the .Rd file. I forget the full list of effects
of each of these, but using both should make your function nearly
invisible, while still exported if it is listed as such in the NAMESPACE
file.
Duncan Murdoch
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