[Rd] ‘:::’ call

[Paul Gilbert]

On 13-08-28 12:29 PM, Marc Schwartz wrote:
>
> On Aug 28, 2013, at 11:15 AM, Paul Gilbert <pgilbert902 at 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?

Paul