[DFDL-WG] rationale for only allowing pattern facet on xs:string type

The pattern facet is allowed on all types in XML Schema. DFDL says the XSDL pattern facet is for xs:string type elements only. What is the rationale for this restriction? We are encountering many constraints in format specs that are using XML Schema regular expressions, where those regex are applied to numeric types (e.g., xs:decimal for lattitude and longitude). -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com