Dear Richy,
Good heavens. Let's not try to quantify this "free" thing too much, please. At the ICMS'2006 in Spain, someone started exactly the same discussion at the end of my talk about CLN: Some people really do believe that if you put your software under a BSD, LGPL, or MIT style license, then the entire closed-source software industry will miraculously be turned into saints and start helping your project by contributing code, doing the debugging for you, organizing events, giving you free lunch, etc.
I don't belong among people believing in that. One should use GPL, or some other copylefted license for that.
That is just so naive. At the ICMS'2006, the GMP (LGPL) developer explained in response, how much feedback he ever got back from Wolfram Research who ship libgmp with Mathematica: absolutely no feedback. Zero, vacuum, null, rien, nada, nix. There was a Wolfram employee in the room then, and I don't really know if the situation has changed since but I wouldn't bet it has.
Yep. One shouldn't blame Wolfram for that though, but those who made GMP LGPL and now cry (if they cry).
Oh, and interestingly, at the end of the old argument why CLisp is GPL you'll find someone foreseeing this problem with GMP: <http://cl-debian.alioth.debian.org/repository/pvaneynd/bzr-moved/clisp/doc/Why-CLISP-is-under-GPL> (CLN wasn't around at that time. But it borrows enough code from CLisp so that this argument applies to it, too. In the end, it's not far-fetched to argue that this decision set the course for GiNaC's license.)
Right.
If you pick another license, that's fine. But, please, be careful not to offend other open-source developers who, by choice or by necessity, made a different pick.
I am sorry if I offended you.
However, we now changed almost everything in sympy, just the class structure stayed - but I mean - it's just a class structure (even that is not 100% the same, we don't use ex for example).
So I wanted to clarify with you, if it's ok, if we use BSD for sympy.
Ondrej, you're going to have fun if you are seriously bringing this up.
IANAL, but you are obviously raising two questions: Is SymPy derived work of GiNaC? Personally, I do not know or care (but don't know about other contributor.) If *you* think it is, then, you must now clarify the situation with the copyright holder for GiNaC. According to the source files, that would be the University of Mainz, Germany. Please, do keep us posted about what comes out from the discussion with their lawyers, okay? Because I don't think they are reading this list. ;-)
I personally don't think SymPy is a derived work, so I am not going to do any actions. I however respect copyrights and licenses, but I am not a lawyer and I don't intend to become a lawyer, so I have just brought it to your attention, since you or other GiNaC developers may have other opinion on this than I do. Ondrej