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Re: Formal Description comments

From: James Clark <jjc@jclark.com>
Date: Fri, 20 Apr 2001 12:00:13 +0700
Message-ID: <3ADFC25D.F80C6F98@jclark.com>
To: "Fuchs, Matthew" <matthew.fuchs@commerceone.com>
CC: XML Schema Comments <www-xml-schema-comments@w3.org>
"Fuchs, Matthew" wrote:

> > 4. How are substitution groups handled?
> >
> 
> Substitution groups are just the element inheritance hierarchy.

I don't understand. Could you explain further?  Are you saying that
substitution groups are already handled by the current XSFD WD?
 
> > 7. I would suggest using * instead of *:* for consistency with XPath.
> >
> 
> In wildcards?  The issue is a consistent notation for:
> 1) any namespace, any local name
> 2) any namespace, fixed local name
> 3) fixed namespace, any local name
> 4) fixed namespace, fixed local name
> *:* is certainly more internally consistent.  I would normally find
> consistency with XPath to be a compelling counter argument, but in this case
> the rest of the syntax for expressing wildcards is so un-XPath that I'm not
> sure anything would be gained.  My coeditors may feel otherwise.

I don't think the design you have is any more consistent than XPath. 
It's not simply a matter of

 fixed v any namespace

and

 fixed v any local name

there's also the distinction between a null/absent and a non-null/absent
namespace. (I think you need this distinction for ##other in
anyAttribute as of the PR.) There aren't enough ways of combining "*"
and ":" to handle all of these combinations.  *:* doesn't seem very
appropriate to match a name with an absent namespace URI.  The XPath
usage of * is consistent with the intuition that * matches one or more
characters of the QName, but there's no QName of the form *:* that
expaned to a name with an absent namespace URI.

James
Received on Friday, 20 April 2001 01:02:06 GMT

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