RE: Bolt-in Type Systems (RE: Relax NG and Web Servi
The ability to specify which datatype libraries are used by the validation language means that if you want to interop with other parties you have to use a standardized set of datatypes. The only [recognized] standardized set of datatypes we have in the XML world has been W3C XML Schema: Part 2. This is what most RELAX NG implementations support. PS: If you need an example, read http://www.oasis-open.org/committees/relax-ng/tutorial-20011203.html#IDA5UYR ________________________________ From: Bullard, Claude L (Len) [mailto:clbullar@i...] Sent: Fri 7/11/2003 6:56 AM To: xml-dev@l... Subject: Bolt-in Type Systems (RE: Relax NG and Web Services (formerly Joining the church)) Somewhere in these interrelated threads, someone mentioned that the RELAX NG approach to type systems was to enable a designer to add their own. How does that work? Are there examples? Some can pretend type issues don't exist or are purely private local affairs. That really doesn't work for languages that initially are defined as object models and treat the XML or other encodings as just that, the bits on the wire representation of what an implementation of that object model needs to operate. True extensibility for these is in the object model, and true interoperability as well. The X in XML is pretty worthless for that. It must be able to express that an extension to the object model is needed and there are ways to do that (eg, modify the schema or DTD, add a namespace, add application language constructs such as X3D PROTOs), but using XML to design extensibility is backwards. Using it to detect it in the document is not. We shouldn't confuse the diet of the animal with the animal. We can't get away from types. Because it seems that for the object model languages, extensibility has to be worked out in the object model first then and only then worked out as an expression in the encodings such as XML application languages or in terms of the metalanguage (eg, namespaces), bolt-in types seem highly desirable and this could be a crucial feature for choosing which schema application languages (eg, XSD, NG, DTD) to normatively specify. len ----------------------------------------------------------------- The xml-dev list is sponsored by XML.org <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this list use the subscription manager: <http://lists.xml.org/ob/adm.pl>
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