- From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Date: Wed, 7 Nov 2001 10:02:52 -0000
- To: <w3c-rdfcore-wg@w3.org>
> > The alternate is to impose the requirement that all lexical > forms of all data types be valid lexical forms for all > superordinate types of that data type. Ouch. Tough to > verify... > > Granted, XML Schema seems to comply with such a requirement > (I haven't checked rigorously though). But whether we > could actualy empose such a requirement (either reasonably > or practically) is questionable. > So, the simple types do appear to follow this. The derived types satisfy this by construction. Derivation by restriction http://www.w3.org/TR/xmlschema-2/#derivation-by-restriction satisfies this by construction. Derivation by list http://www.w3.org/TR/xmlschema-2/#derivation-by-list and by union http://www.w3.org/TR/xmlschema-2/#derivation-by-union satisfies this by virtue of not having a superclass (other than anySimpleType) The primitive datatypes inherit from anySimpleType, which appears by definition to be a union of all the other types, and hence Patrick's condition is satisfied. The complex types (which have XML elements - see message later this morning) seem more difficult, and I think in general Patrick's condition is false. I am new to XML schema though, having only read part 2 last week, and parts 0 and 1 last night. Jeremy
Received on Wednesday, 7 November 2001 05:03:11 UTC