> On 23 Feb 2023, at 11:25, Johannes Veit <leerstr...@gmail.com> wrote: > > Hello Mr. Åberg and thanks a lot for the explanation. > > I attached a pdf where I (try to) explain the Bison exception. > Could you please verify if it is correct?
It is the Bison license exception that is referred to, I believe: Copyright applies to essentially creatively unique parts, but not to machine processed parts. For example, in an editor, what you write is copyrightable, but writer of the editor cannot claim copyright of that material for the electronic processing. Now, Bison processes the grammar one writes, using an algorithm like LALR, and generates output which is not in itself copyrightable by the Bison copyright holder. However, that output is combined with the material in the skeleton file, which Bison now uses M4 for, in the past a simpler type of processor. That skeleton material is copyrightable and forwarded to the output, and therefore the Bison copyright holders must decide what copyright should apply. For situations, GNU has developed the LGPL [1], which does not impose full the GPL license on such material that in nature is like machine processed, but formally not. https://en.wikipedia.org/wiki/GNU_Lesser_General_Public_License
