Re: [xml-dev] Need to import the XML schema namespace

[Liam R E Quin <liam@w3.org>]

On Wed, 2010-05-05 at 20:47 -0700, Jeff Greif wrote:
> Most XML Schemas in the wild reference some of the types in the
> http://www.w3.org/2001/XMLSchema namespace, but they usually do so
> without explicitly importing it, so it apparently unnecessary in
> practice, if not normatively.

> I can't find any reference in the XML Schema 1.0 spec that says it is
> either illegal or unnecessary to import this namespace, for example,
> using xs:import.  Similarly, I can't find any further interoperability
> guidelines on this subject in the WSI-Basic Profile 1.0.

xs:import does not "import a namespace" - it imports a schema that
defines a vocabulary of elements and/or attributes associated with
that namespace URI. This distinction is very important. You could
not write a schema to define xs:integer or xs:string - they are
fundamental building blocks. So, the Schema language has them as
built-ins (in part 2 datatypes), and its neither necessary nor
actually possible to "import" them.

> Does anyone have a reference to a definitive statement of whether this
> import is required, optional or forbidden in XML Schemas that reference
> the data types of this namespace?

It's a meaningless question, you'll be glad to know :-)

Or, it would be like asking which header file you #include in C or C++
to get the keywords like "int" and "switch" and return"...

Hope this helps.

Liam


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Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
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