The SystemRequirements: field of the DESCRIPTION file normally
lists external dependencies whether free or non-free.
On Thu, Sep 10, 2009 at 1:50 PM, Prof. John C Nash <nashjc at uottawa.ca>
wrote:> Subject: Non-GPL packages for R
>
> Packages that are not licensed in a way that permits re-distribution on
> CRAN are frequently a source of comment and concern on R-help and other
> lists. A good example of this problem is the Rdonlp2 package that has
caused
> a lot of annoyance for a number of optimization users in R. They are also
an
> issue for efforts like Dirk Eddelbuettel's cran2deb.
>
> There are, however, a number of circumstances where non-GPL equivalent
> packages may be important to users. This can imply that users need to
> both install an R package and one or more dependencies that must be
> separately obtained and licensed. One such situation is where a new
> program is still under development and the license is not clear, as in
> the recent work we pursued with respect to Mike Powell's BOBYQA. We
> wanted to verify if this were useful before we considered distribution,
> and Powell had been offering copies of his code on request. Thus we
> could experiment, but not redistribute. Recently Powell's approval to
> redistribute has been obtained.
>
> We believe that it is important that non-redistributable codes be
> excluded from CRAN, but that they could be available on a repository
> such as r-forge. However, we would like to see a clearer indication of
> the license status on r-forge. One possibility is an inclusion of a
> statement and/or icon indicating such status e.g., green for GPL or
> equivalent, amber for uncertain, red for restricted. Another may be a
> division of directories, so that GPL-equivalent packages are kept
> separate from uncertain or restricted licensed ones.
>
> We welcome comments and suggestions on both the concept and the
> technicalities.
>
> John Nash & Ravi Varadhan
>
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