Re: LilyPond, LilyPond snippets and the GPL

[Hans Åberg]

> On 30 Oct 2019, at 22:28, Carl Sorensen <address@hidden> wrote:
> 
>> On 10/30/19, 3:17 PM, "Hans Åberg" <address@hidden> wrote:
>> 
>>> On 30 Oct 2019, at 22:14, Carl Sorensen <address@hidden> wrote:
>>> 
>>>>   The snippets should be LGPL for being includable under other licenses, I 
>>>> believe, because the processed part remains in the output, and thus 
>>>> copyrightable. Thus, they play the same role as the Bison skeleton file 
>>>> and GCC libraries.
>>> 
>>> What processed part remains in the output?
>> 
>>    The part of them that one includes in ones own code, if large enough to 
>> be copyrightable. If you just look at them and write something else, it does 
>> not matter.
> 
> How so?  When I wrote fret-diagram code, and before it was accepted in the 
> distribution, it could be contained in an included .ly file.
> 
> When the fret-diagram code was executed, no part of that code ended up in the 
> resulting PDF or PNG files.  The fret-diagram code created ink at specified 
> locations; but the specified locations were not part of the code I wrote.  
> Instead they were generated by the interaction of the main lilypond 
> distribution with the music input I wrote.  And the result was printed music 
> that matched my intent.  If  the music was original, the copyright was mine.  
> If I was transcribing music from another composer, the copyright remained 
> with the composer.
> 
> The GPL had no influence on the copyright of the printed music.

It depends on the snippet then: If it just processes, GPL suffices; if it is 
stuff that remains in the output albeit it processed form, it ought to be LPGL 
if one wants it to freely usable. The Bison skeleton file has stuff that part 
is copied verbatim, part processed with M4, and compiled with languages like 
C/C++, and the copyrightability remains through it all, that is why it is LGPL.

LGPL would be simplest not having to working through all individual cases. But 
that is just my take on it.