[ubl-ndrsc]

[A Gregory <agregory@aeon-llc.com>]

Bill:

Here is some rough text for the transitivity of namespaces piece. You may
wish to explode the examples into the valid namespace names used in other
bits of the versioning paper. I'm assuming you will insert this somewhere
below the point where you explain the need for minor versions to import the
immediately preceding minor version.

Text:

"Note that namespace imports are not transitive (as we see in Part I of the
W3C XML Schema specification, in the section entitled "Schema Representation
Constraint: QName resolution," point 4). As described in point 4, for a
namespace to be referenced it MUST be imported explicitly (or be the target
namespace of the schema in question).

As an example, let us say that we have version 1.1 of the Invoice namespace
cited above. Version 1.2 of that namespace will import version 1.1. Further,
let us say that there is a type declaration X in version 1.0 of that
namespace, which was, of course, imported by the 1.1 version.

If we wish to use type X as a base for extension in the 1.2 version of the
namespace, we cannot simply rely on the fact that we know it was imported
into the 1.1 version, which we have subsequently imported into our version
1.2. We have no ability to reference type X from the 1.0 namespace, unless
we explicitly import it into the 1.2 version.

You MUST explicitly import any namespace containing types that will be used
as the basis for extension or refinement."



Hope this is enough for you - it seemed silly to write a large number of
lines of actual schema code to illustrate something that can be expressed
more simply.

Cheers,

Arofan

P.S. I can't take all the credit since I cut and pasted most of this from
Matt's e-mail... ;-)