RPSLng and nested refine/except expressions
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
Larry J. Blunk wrote:
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.
I use that sort of construct all the time so it better continue to exist! See AS2764 (where I used to work) and AS7575 (my latest effort). RADB's reformatting makes it less obvious but it is a cascading refine. Mark.
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
-- Cengiz Alaettinoglu <Cengiz_Alaettinoglu@yahoo.com>
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
participants (3)
-
Cengiz Alaettinoglu -
Larry J. Blunk -
Mark Prior