Octave and licensing issues

[Andy Adler]

Here is a topic that came up while looking at building a new sparse
implementation for octave.

For some reason, authors of much mathematical software seem to love
inventing their own licenses. Many of them are free, but somehow
conflict with the GPL due to an advertising clause, or some other minor
reason.  For octave to be able to benefit from much of this work,
then it will need to be able to be linked with code under these
licenses.

It looks the like its not a problem for UMFPACK for the sparse code,
but may be a problem in future.

My suggestion was this: explicitly allow this type of linking in the
octave licenses. Thus:

    "This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License ...

    In addition to the terms of the GPL, you may redistribute this
    program with free software that includes an advertising clause,
    ..."

John Eaton's comment was:
> Probably it would make more sense to use a clause that allows
> linking to non-free software through a specific plug-in interface
> only.  But in any case, we can only make a change like this if all
> contributors to the core of Octave can be reached and if they will
> agree to the change.
>
> One difficulty with making a change like this is that it brings up
> the "user does the link" problem with readline, which is GPL and
> which we don't "own", so we can't change the readline license.
> OTOH, the license of Guile includes a similar exception and has a
> readline module that is linked in at run-time, so perhaps there is
> a way to make it work.
>
> If you'd like to discuss this further, then perhaps we should do it
> on the maintainers list.

Does anyone have any strong advice or opinions?

--
Andy Adler