RDDL Schematron Schema

[Jonathan Borden <jborden@mediaone.net>]

I've added a Schematron schema to RDDL (i probably should make y'all look at
http://www.rddl.org/ to find it but its at: http://www.rddl.org/rddl.sch).
Schematron is interesting in that it allows constraints which are otherwise
very difficult to express in for example RELAX or TREX. For example, an
xlink:arcrole and xlink:role must have a value of a URI reference, but not a
relative URI reference. (This could also be expressed in an XML Schema
pattern).

On the other hand I'm not at all sure how to express the constraint that a
rddl:resource have a content model of %Flow.mix; from XHTML. Anyone have a
good idea about this?

-Jonathan