[Rd] Why license filtering is important (was non-GPL ...)

[Prof. John C Nash]

Using the acronym "GPL" in comments on the management of package 
repositories led the discussion well away from the issues I wanted to 
shed light upon, so I have changed the subject tag.

Examples of my concerns:

1) I use a package with a non-free component and learn how to work with 
it efficiently. I'm a retired academic, but still try to recover some 
costs of the work I do for R and other open projects by doing some 
contract and training work. A client has a problem and wants a solution. 
If there is a "non-commercial" restriction, I'm put in the awkward 
position of having to get a permission -- possibly from a defunct 
organization or one that has long forgotten how to grant such a permission.

2) There may be new tools available that ARE free software. Dirk's 
blacklist (perhaps we could have a less loaded name?) may suggest 
opportunities for gradually moving to packages that can be used without 
need to check license details. I have used such tasks in the past as 
student projects where they are relatively straightforward.

3) Many workers are not aware of the consequences of license status of 
their codes (I was not for some years). The development of CRAN and 
similar repositories has been and can be a positive force allowing for 
improvement and understanding of methods.

4) We definitely should retain the ability to access non-free codes -- 
somehow folk have misread my comments otherwise. I'll use them for 
learning and when there is no alternative, but if at all possible, I'll 
choose the free ones for production work so I don't get caught out as above.

A comment: In looking at SparseM, I first used the pdf -- it simply says 
GPL(>=2) as the license. (I'm sure I've got similar bugs in my own 
docs.) I dug deeper and found the LICENSE file, and also looked at 
cholesky.f, which is unfortunately one of the bigger files. I was hoping 
it was somewhat related to work I've done over the years on Cholesky 
decompositions in the hope I could offer a substitute as per concern (2) 
above, but it is not of the same nature as the algorithms I worked on as 
far as I can determine. Maybe someone else is able to step in on that.

And a big tip of the hat to Dirk E. and Charles B. for the cran2deb work 
-- I already admired the work. Now I've started looking at some of the 
package files for license info, I'm amazed they've got as far as they have.

JN