Re: LilyPond, LilyPond snippets and the GPL

[Carl Sorensen]

On 10/30/19, 3:10 PM, "Hans Åberg" <address@hidden> wrote:

    
    > On 30 Oct 2019, at 18:48, Carl Sorensen <address@hidden> wrote:
    > 
    >> In general this is legally impossible; copyright law does not give you 
any say in the use of the output people make from their data using your 
program. If the user uses your program to enter or convert her own data, the 
copyright on the output belongs to her, not you. More generally, when a program 
translates its input into some other form, the copyright status of the output 
inherits that of the input it was generated from.
    >> 
    >> So the only way you have a say in the use of the output is if 
substantial parts of the output are copied (more or less) from text in your 
program. For instance, part of the output of Bison (see above) would be covered 
by the GNU GPL, if we had not made an exception in this specific case.
    >> 
    >> You could artificially make a program copy certain text into its output 
even if there is no technical reason to do so. But if that copied text serves 
no practical purpose, the user could simply delete that text from the output 
and use only the rest. Then he would not have to obey the conditions on 
redistribution of the copied text.
    > 
    > This says to me that you can consider LSR snippets as part of the code 
used to create music (any music, not just your specific music).  You can then 
put your specific music in a separate file, with separate copyright.  And the 
modified LilyPond (including the LSR snippets) is a derivative work of 
LilyPond, and has GPL rights, and you would be required to share all of that 
code.  But the created music engraving (pdf, svg, or midi) is not a derivative 
work of LilyPond, but an output of the program lilypond, and cannot be 
restricted by the GPL, according to the FSF.
    
    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?

Carl