2191 2005-09-14 18:54:20 +0000 R-198: Problem with unions of unions 2009-04-21 19:25:07 +0000 1 1 1 Unclassified XML Schema Datatypes: XSD Part 2 1.0 only All All CLOSED LATER P2 normal --- 1 sandygao cmsmcq www-xml-schema-comments oldest_to_newest 6203 0 sandygao 2005-09-14 18:54:20 +0000 The Union SimpleType Definition Schema Component is defined with the followg properties: {member type definitions} The appropriate case among the following: 1 If the <union> alternative is chosen, then [Definition:]define the explicit members as the type definitions resolved to by the items in the actual value of the memberTypes [attribute], if any, followed by the type definitions corresponding to the <simpleType>s among the [children] of <union> if any. The actual value is then formed by replacing any union type definition in the explicit members with the members of their {member type definitions}, in order. 2 If the <restriction> option is chosen, then the {member type definitions} of the {base type definition}. {facets} If the <restriction> alternative is chosen, a set of facet components constituting a restriction of the {facets} of the {base type definition} with respect to a set of facet components corresponding to the appropriate element information items among the [children] of <restriction> (i.e. those which specify facets, if any), as defined in Simple Type Restriction (Facets) (3.14.3), otherwise the empty set. I believe that it implies a loss of facet restrictions which is highlighted by the following example: <xsd:schema targetNamespace="http:///simple/MySchema.xsd" xmlns:this="http:///simple/MySchema.xsd" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:simpleType name="mySimpleType1"> <xsd:union memberTypes="xsd:nonNegativeInteger xsd:boolean"/> <xsd:simpleType> <xsd:simpleType name="mySimpleType2"> <xsd:restriction base="this:mySimpleType1"> <xsd:enumeration value="true"/> <xsd:enumeration value="0"/> <xsd:restriction> <xsd:simpleType> <xsd:simpleType name="mySimpleType3"> <xsd:union memberTypes="xsd:negativeInteger this:mySimpleType2"/> <xsd:simpleType> <xsd:simpleType name="mySimpleType4"> <xsd:restriction base="this:mySimpleType3"> <xsd:enumeration value="-1"/> <xsd:enumeration value="0"/> <xsd:enumeration value="1"/> <xsd:enumeration value="true"/> <xsd:enumeration value="false"/> <xsd:restriction> <xsd:simpleType> <xsd:schema> Since the literal value "1" and the literal value "false" are not in the value space of mySimpleType2 nor in the value space of negativeInteger, they would appear to be in error. But a literal interpretation of the definition would imply that mySimpleType3 is just a union of negativeInteger, nonNegativeInteger, and boolean and hence "1" and "false" are valid literals. Isn't this quiet loss of explicit facet restrictions a problem? 6204 1 sandygao 2005-09-14 18:59:27 +0000 Discussed at the April 10,2003 telecon. No decision reached. ACTION: Paul Biron to work this out in painful detail. Resolution: At the June 12 2003 telecon: RESOLVED: Class R-198 as error to be fixed in 1.1.