Re: [Question]:Question about bison adding GPL copyright to the parser files generated by bison and yacc.c

[Christian Schoenebeck]

On Samstag, 26. Januar 2019 14:31:06 CET Hans Åberg wrote:
> > On 21 Jan 2019, at 17:24, bird bravo <address@hidden> wrote:
> >    I noticed that when I use bison and the parser skeleton(yacc.c) to
> > 
> > generate a parser file... there will be a copyright notice to claim the
> > file is a GPLV3 and an exception declaration... I wanna know is that OK to
> > use and distribute the parser file as I wish..
> 
> Yes, see [1]. The copyright applies to the skeleton code which is copied
> over to the generated parser, but there is an exception added for that.
> 
> 1. https://www.gnu.org/software/bison/manual/html_node/Conditions.html

No, that's not what the exception sais. The exception applies (and hence the 
freedom to distribute a Bison generated parser under any arbitrary, different 
license than GPL) only if the generated parser is not itself a parser 
generator. This is not as obvious as you might think. It really depends on 
what his generated parser is capable to do.

I give you a simple example: let's say you used Bison to develop a tool which 
converts source code from one programming language A to B. Now you might think 
this is not a parser generator. Well, it was obviously not your intention. But 
now consider somebody uses that conversion tool for converting a parser  
originally written in programming language A to language B.

Right, your Bison generated conversion tool just generated a parser.

Best regards,
Christian Schoenebeck