Re: LilyPond, LilyPond snippets and the GPL

[Hans Åberg]

> On 31 Oct 2019, at 22:10, David Kastrup <address@hidden> wrote:
> 
> Hans Åberg <address@hidden> writes:
> 
>>> On 31 Oct 2019, at 21:31, David Kastrup <address@hidden> wrote:
>>> 
>>>> All those parts should be LGPL, and also included headers, I believe:
>>>> Not GPL, because that would legal technically force copyright
>>>> limitations on the output, and not public domain, because then one
>>>> could exploit the inputs in ways you do not want. But check with the
>>>> experts.
>>> 
>>> I think this kind of stuff should just be exempt from licensing (namely
>>> declared public domain) like stub code in GCC.  It doesn't survive into
>>> PDF anyway (since PDF is not programmable and so the PostScript-to-PDF
>>> conversion executes the code in question rather than converting it) and
>>> it is very unusual to distribute PostScript these days instead of
>>> executing it right away in the form of some document processing
>>> workflow.
>>> 
>>> So that is indeed something that would warrant getting separate
>>> appropriate licensing attention, but in most use cases it would end up
>>> not being relevant since there are few workflows where a PostScript file
>>> ends up as something to be distributed.
>> 
>> It is only a problem if code survives in the output and is
>> copyrightable. Like glyph designs, for example, there are in the works
>> new microtonal accidentals, the design of which I figure would be
>> copyrightable, and take a long time to develop. Would you want them to
>> be in the public domain? It would mean that the design could be
>> exploited freely without acknowledgement. With LGPL, any altered
>> design must have the same license, but the glyphs can be used freely
>> in publications.
> 
> If I remember correctly, our fonts have already been relicensed under
> some typical free font license several years ago.

That is good. I merely wanted to illustrate the principle, that some stuff may 
survive into the output in copyrightable form. The most explicit example I have 
in my mind is the Bison skeleton file that originally was mostly verbatim, but 
now is processed using M4, and needs to be LGPL, not GPL, nor public domain.