Re: LilyPond, LilyPond snippets and the GPL

[Karsten Reincke]

On Wed, 2019-10-30 at 15:08 +0100, Henning Hraban Ramm wrote:

[...]

It’s the same if you publish a book using TeX:

No, it isn't.

While original TeX is PD and some other parts have their own licenses, those never apply to the contents of your book or the PDF or printed version of it,

That's an unproven proposition

because the code of TeX (or LilyPond) isn’t in there, it was just used to generate the result. (Same if you use OS software to generate graphics, videos etc.)

Not it isn't.

Again - like others in this thread - you are mixing the cases

a) The GCC, the TeX-engine, and LilyPond are programs, which take a piece of source code and compile the output (Binary, PDF, PNG).

b) The licenses of these engines do not influence the licensing of the input or output.

c) But if the gcc compiles a source code, which uses the prework of a GPL licensed library, snippet, or anything else, then - in accordance to the GPL-v3 §6 - the compiled program (binary) has also to be distributed under the terms of the GPL (strong copyleft effect). If you deny this statement, then you argue against the idea of the Free Software itself.

d) If the TeX engine compiles a LaTeX source code, which uses the prework of a GPL licensed style or anything else, then indeed - in accordance to the GPL-v3 §6 (titled "Conveying Non-Source Forms"), the compiled result (the PDF etc.) has to be distributed under the terms of the GPL too. That's stated in and by the LaTex community (e.g. https://tex.stackexchange.com/questions/69007/the-gpl-and-latex-packages ). And that's the reason, why ctan mostly does not contain GPL licensed packages.

e) If the LilyPond engine compiles a LilyPond music source code, which uses the prework of a GPL licensed LilyPond snippet, then - in accordance to the GPL-v3 §6 (titled "Conveying Non-Source Forms"), the compiled result (the PDF, PNG) has to be distributed under the terms of the GPL too.

Why should c) and d) be valid, but not e)? You can't have and eat the cake.

If we want to protect the 'biotope' of free and open source software from being misused and if we want that others respect the licensing rules, then at least we have to take the license texts as seriously as possible. They are not a hawker's tray from which we can take what we love and ignore the rest.

With best regards Karsten