relax-ng grammar for xacml

What is the sense of the TC about putting out normative or informative
relax-ng grammar definitions for xacml?

A quick search of the mail archives did not reveal any discussion on
this topic.

When I started writing xacml I used msv and trang to produce rnc files.
I'm no expert in grammar languages, but would be willing to help produce
rng/rnc definitions of xacml.

--Paul