Re: [Haskell-cafe] GPL License of H-Matrix and prelude numeric

On Tue, 2011-01-25 at 22:21 -0800, John Millikin wrote:

On Tue, Jan 25, 2011 at 22:14, Ivan Lazar Miljenovic wrote:

...

However, my understanding that this property is then transitive: if Foo is GPL, Bar depends on Foo and Baz depends on Bar, then Baz must also be released under a GPL-compatible license.

It's not really a "must", just a matter of practicality.

If you compile/link together code with incompatible licenses (BSD4 + GPL, GPL2-only + GPL3-only) then the resulting binary can't be legally distributed for any reason (because doing so would violate at least one of the licenses). You can still license the source code however you want, and distribute it; the problem is only for binaries.

The text of GPL-2 and GPL-3 at least have note about upgrading so GPL-2 program can be relicensed into GPL-3. ANAL but I think the legal framework of US makes it relatively safe (status of FSF prevents it from 'being evil'). Some projects (like Linux) remove this clause and I'm not sure how many projects are marked on hackage as GPL2 being GPL2-only. Regards PS. I may be wrong but on the first sight GPLx and GPLx-only seems to be noncompatible.