[Rd] Non-GPL packages for R

[Prof. John C Nash]

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