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Re: Which license am I looking for?



Thanks for your reply.

On Sun, Jan 18, 2009 at 05:43:05PM +0100, Francesco Poli wrote:
> On Sun, 18 Jan 2009 15:58:06 +0100 Mark Weyer wrote:
> 
> [...]
> > On Sun, Jan 18, 2009 at 01:49:35PM +0100, Mark Weyer wrote:
> > > - Copyleft with source requirement, but should not contaminate other
> > >   software.
> [...]
> > Maybe I should have been less terse.
> > - With "source requirement" I meant that source code of derived works must
> >   be made available.
> 
> This is, IMO, one of the key features of a copyleft license.

Well, according to Wikipedia, copyleft just says that redistribution is
allowed under the same terms, nothing about source. So I mentioned
source requirement separately, just to make sure.

> > - "no contamination of other sofware" was meant to imply, that if someone
> >   uses (a derived version of) my software as part of hers, she does not
> >   have to put her entire work under my license.
> 
> I think the opposite of this is another key feature of a copyleft
> license!
> 
> E.g.: the GNU GPL imposes that works incorporating a GPL'ed work (or a
> derivative of a GPL'ed work) may only be distributed under the terms of
> the GNU GPL itself.
> The only exception is the case of "mere aggregation": see the license
> text for more details.
> 
> Hence, I think your desiderata are somewhat inconsistent.

I think what you refer to, is what GNU calls strong copyleft. What I want
is more close to weak copyleft.
I want, that in the event of my software becoming part of some larger
software, that all recipients have access to my software in its best form,
that is in source. Hence copyleft with source.
While I would also prefer that recipients have access to the sources of the
other parts of the larger software, I think it unwise to require that the
other parts are put under the same license. The reason being, that if some
other part of the larger software does the same, albeit with a different
license, the larger software becomes undistributable, which is the worst
possible outcome.

I do not see that this is inconsistent.
Or maybe I just understand "mere aggregation" much broader than you.
Or than the GPL does. In particular, if my software becomes a library, I
do not want a mere include to imply that the whole program is derived work.

> Back to your question: I personally think you should revise your
> desiderata, since you seem to search for a broken copyleft, which is,
> well... , not what I would really recommend!   ;-)

I have given arguments for my desiderata above, and I would be happy to
provide more. But this leads away from my initial question.

> My personal suggestions are:
> 
>   * first, decide if you really want a copyleft
>   * in case you really want a copyleft, I _strongly_ recommend a
>     GPLv2-compatible license: for instance
>       -  the GNU GPL v2 itself (only v2, or, if you prefer, with the
>          "or later" phrasing)
>          http://www.gnu.org/licenses/gpl2.txt

Among other shortcomings, GPL contaminates other software.

>       -  or the GNU LGPL v2.1
>          http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt

LGPL 2.1 distinguishes all sorts of software right in the definitions:

|   A "library" means a collection of software functions and/or data
| prepared so as to be conveniently linked with application programs
| (which use some of those functions and data) to form executables.

Similar LGPL 3.0:

|   The object code form of an Application may incorporate material from
| a header file that is part of the Library.  You may convey such object
| code under terms of your choice, provided that, if the incorporated
| material is not limited to numerical parameters, data structure
| layouts and accessors, or small macros, inline functions and templates
| (ten or fewer lines in length), you do both of the following:

I do not want to distinguish between different kinds of software.
The reason is, that while at this time my software is best described
as "program", I acknowledge, that through a sufficient number of
mutations (in the process of deriving works) it might as well become
a picture, a library, documentation, or whatnot. (More likely, it
will first become something which does not fall into any category.)
I do not want the semantics of the license to depend on such.
In particular, I want to understand, for myself, what the semantics are
in any such case.

>   * in case you conclude you do not want a copyleft, I recommend a
>     simple non-copyleft license: for instance
>       -  the Expat/MIT license
>          http://www.jclark.com/xml/copying.txt
>       -  or the 2-clause BSD license
>          http://www.debian.org/misc/bsd.license (without clause 3.)
>       -  or the zlib license
>          http://www.gzip.org/zlib/zlib_license.html

I do want copyleft.

Best regards,

  Mark Weyer


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