Bison's licence

[helios]

I was going to post this in the OSS thread, but then I thought that it might end up not being read, so I thought it was better to start a new one.

I found this on the Bison skeleton:

As a special exception, you may create a larger work that contains
part or all of the Bison parser skeleton and distribute that work
under terms of your choice, so long as that work isn't itself a
parser generator using the skeleton or a modified version thereof
as a parser skeleton. Alternatively, if you modify or redistribute
the parser skeleton itself, you may (at your option) remove this
special exception, which will cause the skeleton and the resulting
Bison output files to be licensed under the GNU General Public
License without this special exception.

Am I misinterpreting this, or does this mean that the generated parser can be included in, say, a public domain interpreter while maintaining the licence of the interpreter as a whole public domain?

For those of you who don't know, when GPL'd code is linked to GPL-compatible code, such as public domain or permissive, the project as a whole (not the individual sources) becomes GPL'd.

[jsmith]

I read it as meaning that Bison's license does not apply to your project except under the case where you
use Bison to create a better Bison. In that case, if you use Bison's generated parser code unmodified, then you're stuck with Bison's license. But if you modify the generated code, then you're not.

[helios]

Yes, I thought so, too.

Phew!