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

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

I think the problem depends on whether the schema will be used only for validation or whether it will be used for type augmentation as well. There is a big difference between check to see if this number is prime (validation) and the datatype of this number is prime number (type augmentation). One is feasible to implement in modern systems while the other is not. 
 
As for datatype libraries being in conflict, I guess I need to see an example scenario before I can confirm or deny that it is possible. Some would probably consider the ability to create union types and ambiguous grammars as potentially creating datatype conflict. However I am not sure this is what you mean. 

________________________________

From: Bullard, Claude L (Len) [mailto:clbullar@ingr.com]
Sent: Fri 7/11/2003 11:57 AM
To: Dare Obasanjo; xml-dev@lists.xml.org
Subject: RE: [xml-dev] Bolt-in Type Systems (RE: [xml-dev] Relax NG and Web Services (formerly Joining the church))



Thanks Dare.   I appreciate that URL.

Where we get into difficulties is when that set of types
isn't adequate given a particular object model.  The X3D
XML Schema covers the XSD types, but it wasn't a great
fit.  The topic now becomes whether or not it is better
for X3D systems to have their own datatypes or to mix
and match.  I suspect that as you say, it will depend
on what they must interop with.  But interoperation is
in the object model, not the means of denoting the
library.  So putting validation up front seems to be
putting the cart in front of the horse.  One must
first know what datatypes the object model specifies,
then ensure the validation language includes these.
The case for RNG is stronger.

What happens to an RNG implementation if two datatype
libraries are in conflict?  Can that happen?  One
expects that not to happen to a given object model
(say X3D) by definition, but intuitively, I can think
of that happening given an aggregate or where two
models must interoperate (say X3D inside or wrapping
HTML).  Must be a pain for the framework (say operating
system).

len


From: Dare Obasanjo [mailto: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