Dear Urs; many thanks for your clever thoughts! You brought up a very seductive argument, which I therefore will only summarize here for being sure that I've understood you correctly. May I condense your line of argumentation in the following way?
You point out that there could be a function in a GPL licensed snippet which only modifies the apperance of a score. Such a function does not concern the music itself. And therefore, the copyleft effect is not applied of the music. Then it seems that you try to generalize your argumentation: Every piece of LilyPond code describing the music score does not not concern the music, but only the appearance. Hence the, the copyleft effect can not be applied to any results of the LilyPond compilation process (the pdfs, pngs, ...) Please tell me, whether I got your point or not. Again, it seems to seductive and I want to consider it a bit longer, before I will answer best regards karsten
