2783 2006-01-30 18:39:44 +0000 constituting a restriction 2009-10-09 22:50:29 +0000 1 1 1 Unclassified XML Schema Structures: XSD Part 1 1.1 only PC Linux CLOSED FIXED restriction cluster resolved P2 normal --- 1 cmsmcq cmsmcq cmsmcq David_E3 www-xml-schema-comments oldest_to_newest 8050 0 cmsmcq 2006-01-30 18:39:44 +0000 Clause 3 of Schema Component Constraint: Simple Type Restriction (Facets) in section 3.14.6 of Structures appeals to the concept of one set of facets R 'constituting a restriction' of another set B, with respect to a 3d set S. This raises two issues. First, the appeal is confusing because the concept in question is not really one of restriction but of an operation sometimes called 'set overlay' or 'priority union' (or probably other things as well): take everything from one set, and everything from the second set except those members which match elements in the first set (for some definition of matching other than identity, since if matching is based on identity this is just a union). Given the sets B = {minInclusive = 0, maxInclusive = 20} S = {maxInclusive = 100} R = {minInclusive = 0, maxInclusive = 100} then B, S, and R satisfy the definition, but R does not actually constitute anything one would be inclined to call a restriction of B. It does constitute the overlay of B with respect to S, or the priority union of S and B (in that order). So I think the term should be changed. Second, in the face to face meeting this morning, Henry and Sandy suggested that the purpose of this component constraint was not really to constrain components but to provide a definition of this term. They proposed that we should delete it here and move the relevant bits to the place in Datatypes which was, as far as they could tell, the only place that refers to this constraint. So we need to decide what to do about this proposal to move the constraint or its contents. 27023 1 David_E3 2009-09-10 21:44:05 +0000 decided at the telcon 2009-09-04 28183 2 cmsmcq 2009-10-09 22:49:59 +0000 As noted in comment 1, the WG approved a wording proposal (at http://www.w3.org/XML/Group/2004/06/xmlschema-1/structures.b2783.html) (member-only link) to resolve this issue; essentially, it replaces the phrase "R constitutes a restriction of B with respect to S" with the phrase "R is the result of overlaying B with S". The change is now in the status quo document, so I'm closing the issue. 28184 3 cmsmcq 2009-10-09 22:50:29 +0000 As the originator of this issue I can confirm that I am satisfied with the resolution.