RE: How compatible are XML Schema implementations?

["Arnold, Curt" <Curt.Arnold@hyprotech.com>]

There isn't much overlap between platforms, so it seems at this instant you are tied to a specific implementation once you have chosen your platform.

Xerces-J doesn't support the Candidate Recommendation and probably will skip to whatever comes next, so if you use it you will not be interoperable with anything else.  I'd recommend avoiding it until
it catches up.

Oracle's Schema Processors for Java, C++ and C seem to be the only Candidate Recommendation implementations on those platforms.

XSV is written in Python (maybe it could also be called from Java using JPython).

I don't know if you could use XML Spy's COM interfaces to perform schema validation on Windows.

Until schema conformance tests are published and the implementations start becoming more complete, you basically have to check your schemas against multiple processors to make sure that you aren't
running into a bug, unimplemented feature, or misinterpretation of the spec.  OASIS has a working group for XML Schema conformance but I'm not aware of its state.  I started a test suite for the April
draft at http://xmlconf.sourceforge.net, but haven't revisited it for the Candidate Recommendation.  If and when OASIS publishes a suite, I assume that the xmlconf project will provide harnesses to
test the major implementations.

Did I leave anybody's favorite processor out?