[Bug 3222] Identity and Equality

http://www.w3.org/Bugs/Public/show_bug.cgi?id=3222

           Summary: Identity and Equality
           Product: XML Schema
           Version: 1.1 only
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Datatypes: XSD Part 2
        AssignedTo: cmsmcq@w3.org
        ReportedBy: mike@saxonica.com
         QAContact: www-xml-schema-comments@w3.org


QT-approved comment.

Having introduced the notion of equality of values (as distinct from
identity) it is surprising that it is not used more widely, for example in
applying enumeration facets, fixed values, or referential integrity
constraints (the term "identity constraints" is a little unfortunate).
Generally, the closer we can align the XML Schema comparison semantics with the
XPath comparison semantics, the fewer surprises there will be for users.

Furthermore, the distinction is not always carried through. For example, I
would have expected section 2.6.1.2 to say how the notions of identity,
equality, and ordering apply to the values of a list type. Is this somewhere
else, and if so, should there be a cross-reference? I would also expect a more
formal statement that the value space of a list type is the set of sequences of
values of the item type, minus any values of the item type all of whose lexical
representations contain whitespace.

As with lists, one would expect section 2.6.1.3 to contain a discussion
of the identity, equality, and ordering relations applicable to union types.

Received on Tuesday, 9 May 2006 09:38:39 UTC