Experiences with the Design of the W3C XML Schema Definition Language

XML and RDF are different in many ways, but it is possible that some of the challenges that arose in designing a validation system for XML will have equivalents in the Semantic Web world. The purpose of this paper is to suggest a few such areas for consideration. In some cases, the nature of RDF itself will suggest design approaches different from those used for XML Schema, e.g. that schema information be represented as RDF triples. Indeed, there is no intention here to imply that the solutions adopted in the XML Schema Definition Language (XSD) [Schemas] were in all cases good ones even for XML. Rather, the hope is to point out some general areas that might be considered in building a validation system for the Semantic Web. These suggestions are based on my experiences as a member of the W3C XML Schema working group and co-editor of the schema structures specification, but the opinions in this position paper are mine alone.