RE: [xml-dev] Bolt-in Type Systems (RE: [xml-dev] Relax NG and Web Services (formerly Joining the church))

["Dare Obasanjo" <dareo@microsoft.com>]

The ability to specify which datatype libraries are used by the validation language means that if you want to interop with other parties you have to use a standardized set of datatypes. The only [recognized] standardized set of datatypes we have in the XML world has been W3C XML Schema: Part 2. This is what most RELAX NG implementations support. 

PS: If you need an example, read http://www.oasis-open.org/committees/relax-ng/tutorial-20011203.html#IDA5UYR 


________________________________

From: Bullard, Claude L (Len) [mailto:clbullar@ingr.com]
Sent: Fri 7/11/2003 6:56 AM
To: xml-dev@lists.xml.org
Subject: [xml-dev] Bolt-in Type Systems (RE: [xml-dev] Relax NG and Web Services (formerly Joining the church))



Somewhere in these interrelated threads, someone mentioned
that the RELAX NG approach to type systems was to enable a
designer to add their own.  How does that work?  Are there
examples?

Some can pretend type issues don't exist or are purely private
local affairs.  That really doesn't work for languages that
initially are defined as object models and treat the XML
or other encodings as just that, the bits on the wire
representation of what an implementation of that object
model needs to operate.  True extensibility for these is
in the object model, and true interoperability as well.

The X in XML is pretty worthless for that.  It must be
able to express that an extension to the object model
is needed and there are ways to do that (eg, modify
the schema or DTD, add a namespace, add application
language constructs such as X3D PROTOs), but using
XML to design extensibility is backwards.  Using it
to detect it in the document is not.  We shouldn't
confuse the diet of the animal with the animal.

We can't get away from types.  Because it seems that
for the object model languages, extensibility has to
be worked out in the object model first then and only
then worked out as an expression in the encodings such
as XML application languages or in terms of the metalanguage
(eg, namespaces), bolt-in types seem highly desirable and
this could be a crucial feature for choosing which schema
application languages (eg, XSD, NG, DTD) to normatively
specify.

len

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