RE: [ubl-cmsc] XSD Derivation

[Matthew Gertner <matthew.gertner@schemantix.com>]

This seems to be the only point where I have a strong opinion that is not
the same as yours and Eve's. How boring...

In this case, I feel strongly that XSD derivation should ALWAYS be used when
creating extensions. Sorry to go "visionary" on you guys, but I'm convinced
that the whole power of schema is that standard processing tools can be
used. One of the really clever things that these standard processing tools
will do is to be able to treat extended types that they don't know as if
they were base types that they do know. In other words, I might use a schema
processor to write code to process a Price type. If someone sends a MyPrice
(derived from Price) to my processor, it will just see a Price since the
schema processor will deal with hiding the extensions, restrictions, etc.

I'm not flying entirely blind here, since this is the way that existing
schema processors, like Commerce One's XDK, work.

We want to design a framework that exploits the power of these future schema
processors, and this means that UBL extensions should be standard schema
extensions supported by standard schema processors. Also, I haven't heard
anyone suggest that we should allow extensions that aren't permitted in XSD,
although it was implied by Eduardo and Eve's mails that this might be
desirable. Can someone provide an example?

Matt

> -----Original Message-----
> From: Eduardo Gutentag [mailto:eduardo.gutentag@sun.com]
> Sent: Friday, November 16, 2001 11:50 PM
> To: Matthew Gertner
> Cc: 'ubl-cmsc@lists.oasis-open.org'
> Subject: Re: [ubl-cmsc] XSD Derivation
> 
> 
> Matthew Gertner wrote:
> > 
> > 2) Should XSD derivation be used when context rules are 
> applied: always,
> > sometimes or never? In others, what is the derivation 
> relationship, if any,
> > between contextual components and the base components that 
> yielded them?
> 
> Another way of posing the question would be:
> Should context rules be applied as
> a) a schema to schema tranform to avoid the restrictions 
> imposed by XSD derivation? 
> or as
> b) XSD derivation to preserve the derivation relationship?
> 
> I have to confess that at this point I'm extremely agnostic 
> on this point, since
> I can see the advantages of both...but I'm ready to be 
> lobbied for one way or another.
> 
> > 
> > ----------------------------------------------------------------
> > To subscribe or unsubscribe from this elist use the subscription
> > manager: <http://lists.oasis-open.org/ob/adm.pl>
> 
> -- 
> Eduardo Gutentag               |         e-mail: 
> eduardo.gutentag@Sun.COM
> XML Technology Center          |         Phone:  (510) 986-3651 x73651
> Sun Microsystems Inc.          |
>