- From: Michael Kay <mike@saxonica.com>
- Date: Mon, 27 Apr 2009 17:16:42 +0100
- To: "'Costello, Roger L.'" <costello@mitre.org>, <xmlschema-dev@w3.org>
> I'm not clear on (b) but (a) certainly sounds like the > decision to disallow doc() for cross-document validation was > done to make it easier to implement 1.1 schema validators. No, I don't think that's the case. I think the working group felt that introducing context-dependent validation (where the validity of a document depends on factors other than the schema and the instance document) was a risky architectural innovation, and possibly a step that would be later regretted. I don't think implementation factors came into it once the decision was made to support the full XPath syntax and function library. I discovered when I tried to do it that implementation was trickier than I thought, but it's not difficult, and certainly I don't think the WG avoided it for that reason. Personally, I would like to experiment/innovate with context-dependent validation, for example by allowing assertions to reference XPath variables supplied when the validation is invoked; perhaps even variables that can be bound while validating an ancestor element. I think it could be a very powerful feature - though I'm sure users would use it in ways I can't currently imagine. Michael Kay http://www.saxonica.com/
Received on Monday, 27 April 2009 16:21:02 UTC