RPSLng and nested refine/except expressions

  Thanks, Cengiz.  This greatly simplifies things.  I'll update the draft
to use the cascading style and note the issue with the example
in 2622.

  -Larry

On Tuesday 11 May 2004 14:53, Cengiz Alaettinoglu wrote:
> Historical perspective:
> 	- first there was the nested syntax
> 	- then it got replaced by the cascading syntax since the sematics were
> simpler
> 	- one example using the nested syntax unfortunately stayed in the
> document.
>
> Note that RPSL only defines semantics for the cascading form.
>
> On Fri, 2004-05-07 at 14:17, Larry J. Blunk wrote:
> >   In the -04 version of the RPSLng draft, the structured policy syntax
> > was updated to allow nested refines and excepts in policy expressions. 
> > I.e.
> >
> >   refine {
> >     <expression>
> >      refine {
> >          <expression>
> >      }
> >   }
> >
> >    Examples of such expressions are given both RFC2622 and the RPSLng
> > draft.   However, the original RFC2622 syntax did not actually allow such
> > expressions.
> >
> >    However, in the process of implementing and running the syntax check
> > on existing objects, I have found examples of the following:
> >
> >   refine {
> >      <expression>
> >      } refine {
> >         <expression>
> >      }
> >
> >      See, for example, AS7574 in the RADB.  Unfortunately, such
> > expressions are invalid in the lastest RPSLng draft.   Are such
> > expressions semantically identical to nested refines/excepts?    Should
> > both this form and the nested form be allowed.    I have come up with a
> > minor modification to the -04 syntax that would allow both, but I'm not
> > sure if it is a good idea or not.
> >
> >    -Larry