Further changes as I dig deeper

I am trying to write a CAM validator.  I have come up with a few minor change requests:

1) I have added a wrapper under Rules for the contextSpecific Rules.  It helped with my parsing - probably can get by without.

2) I am looking at conditions and finding the parsing of them very complex as we have CAM expressions and xpath mixed together. So I am making some minor suggestions:
In condition statements:
a) xpaths must be wrapped with xpath('XPATHEXPRESSION')  This way you can know something should be interpreted as an xpath rather than a literal.  Also it saves having to parse the contents of the xpath
b) first version should not allow nested conditions

Alternatively if someone out there has a neat way of evaluating the conditions with a convenient java class it would be good.
What do you think?