Just to clarify some more, my contention is that you cannot look inside a arbitrary URI to pick out values without looking at the formal 'scheme' dependent spec.
So in the case of a 'http' URI, we can read the spec and know what the bits mean - _for the purposes of fetching data from web servers using HTTP_. I can't imagine how that is possibly what is intended by putting a URI into an archetype - we can't seriously be suggesting that everyone who uses the archetype is all going to be descending on some poor webserver named in the URL and fetching data in some arbitrary format? So if you want a URI scheme that has identifiable bits for snomed queries etc, someone needs to specify a urn:snomed:xxxx,yyyy,zzzz spec. If not, all you can do is compare URI's for equality and assume there is some external mechanism for saying what the URI actually means. Andrew
