Michael, Thank you for bringing up this issue as it does clarify some aspect of Sage derived code and licensing. But, in my mind, the "sage as interpreter" aspect is a small perturbation on top of the zero-order:
Sage = Python + GPL libraries That is, for the most part, I view the interpreter as Python itself. But still the FAQ section is very clear that the presence of all the GPL libraries loaded into an interpreter is sufficient to make sage using scripts like Ondrej's GPL bound. I also understand that not everyone agrees on this interpretation. But in my mind, that was the TRIVIAL part of the original question I asked. The more subtle aspect is centered around this issue: * Does "Sharing" a notebook (with other users of the notebook web app) constitute distribution and is that sufficient to trigger the application of the GPL? In other words, do I need to tell my students... "When you share your Sage notebooks with me and other's in the class, you must agree to license them under the GPL" Cheers, Brian PS[0] = even though I choose to use the GPL myself sometimes, this is what I hate about it. It is too damn complicated. Even on a strongly pro-GPL project like Sage, it doesn't seem like most people have any idea what it says and means. I don't mean to pick on anyone individually, but on this thread, I have heard _multiple_ different and incompatible interpretations of the GPL. PS[1] = It is even more ironic to me that Ondrej and I are the ones arguing for the FSF interpretation of the GPL as we are typically found in the pro-BSD camp. From my perspective, many Sage devs and users are doing things with Sage derived code that violates the canonical interpretation of the GPL. If that is just fine, then does the GPL actually mean anything? (I think it does even though there is some ambiguity!) On Tue, May 5, 2009 at 8:46 PM, mabshoff <mabsh...@googlemail.com> wrote: > > This is the relevant entry from the GPL FAQ: > http://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL > > To quote: > > [quote] > If a programming language interpreter is released under the GPL, does > that mean programs written to be interpreted by it must be under GPL- > compatible licenses? > > When the interpreter just interprets a language, the answer is no. The > interpreted program, to the interpreter, is just data; a free software > license like the GPL, based on copyright law, cannot limit what data > you use the interpreter on. You can run it on any data (interpreted > program), any way you like, and there are no requirements about > licensing that data to anyone. > > However, when the interpreter is extended to provide “bindings” to > other facilities (often, but not necessarily, libraries), the > interpreted program is effectively linked to the facilities it uses > through these bindings. So if these facilities are released under the > GPL, the interpreted program that uses them must be released in a GPL- > compatible way. The JNI or Java Native Interface is an example of such > a binding mechanism; libraries that are accessed in this way are > linked dynamically with the Java programs that call them. These > libraries are also linked with the interpreter. If the interpreter is > linked statically with these libraries, or if it is designed to link > dynamically with these specific libraries, then it too needs to be > released in a GPL-compatible way. > > Another similar and very common case is to provide libraries with the > interpreter which are themselves interpreted. For instance, Perl comes > with many Perl modules, and a Java implementation comes with many Java > classes. These libraries and the programs that call them are always > dynamically linked together. > A consequence is that if you choose to use GPL'd Perl modules or Java > classes in your program, you must release the program in a GPL- > compatible way, regardless of the license used in the Perl or Java > interpreter that the combined Perl or Java program will run on. > [end quote] > > Since Sage has bindings to GPLed libraries, i.e. libSingular to make > one example, according to the FSF a Sage program would be derived from > a GPLed combined work and would have to be licensed GPL compatible *if > distributed*. > > So, in the end it depends if you share the FSF's interpretation of the > GPL to be that far reaching or not. > > IMHO they are overreaching, but IANAL on one hand and on the other > hand have no problem licensing anything I write in Sage under the GPL. > > Cheers, > > Michael > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
