- From: Jeni Tennison <jeni@jenitennison.com>
- Date: Sat, 9 Mar 2002 12:56:37 +0000
- To: noah_mendelsohn@us.ibm.com
- CC: xmlschema-dev@w3.org
Hi Noah, > Also: Schematron is relatively declarative; my concern was primarily > with the possible jump to non-declarative languages. It's much > easier for tools to reason about constraints captured declaratively > (e.g. in schema facets or derivations, or even Schematron > assertions) than imperatively (in a Java loop). Yep. Naturally I was thinking of XSLT as the Turing-complete, W3C-approved, declarative language of choice. > The ability to build tools that manipulate and derive information > from schemas is of key importance. Writing programs that validate > documents or types may not get us that. Absolutely. In my mind, there are three primary purposes to schemas - validation, documentation and tool support. A rule-based approach is great for validation, and as Schematron shows can be combined with documentation, but really suffers in terms of providing support for tools (for helping people author XML, or for analysis prior to query/transformation for example). I think that the object-oriented approach of XML Schema provides a big win in this area, and I'm certainly not advocating that this is lost. However, I think that at the moment XML Schema's validation power and flexibility suffers because of its focus on tool support. I am simply arguing that incorporating a rule-based approach seems a neat way of correcting that balance. Anyway, I'm sure that the XML Schema WG are considering all kinds of changes; just thought a little bit of user input couldn't hurt once in a while. Cheers, Jeni --- Jeni Tennison http://www.jenitennison.com/
Received on Saturday, 9 March 2002 07:56:40 UTC