Re: What is a Parser Skeleton?

[Hans Åberg]

> On 23 Feb 2023, at 11:25, Johannes Veit <leerstring@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