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Re: Substitution group chains - which can be abstract?

From: Dan Vint <dvint@mindspring.com>
Date: Fri, 18 Apr 2003 08:23:29 -0700
Message-Id: <5.1.0.14.2.20030418082019.00a7f838@mail.dvint.com>
To: <xmlschema-dev@w3.org>

What would be the purpose in saying that this group X based upon this 
abstract head Y, has all these things that can substitute for it and then 
have one of those substitution items also have abstract applied to it?

Now the head and an internal member both cannot be used in the data stream. 
Maybe you might get the use of the second element for use in the schema but 
the end result would be the same wouldn't? You sort of have 2 head 
elements, but only one common set of substitution elements.

..dan

At 11:08 AM 4/18/2003 +0800, Simon Cox wrote:
>I was looking in part 1 rather than the primer.
>Can you (or anyone else) point me to the normative section in part 1 where
>it states that only the head of a substitution group may be abstract?  I
>looked but could not find it.
>
>I don't see the benefit in this restriction.
>
>Simon Cox
>
>----- Original Message -----
>From: "Dan Vint" <dvint@mindspring.com>
>To: <Simon.Cox@csiro.au>; <Simon.Cox@csiro.au>; <xmlschema-dev@w3.org>
>Sent: Thursday, April 17, 2003 11:30 PM
>Subject: Re: Substitution group chains - which can be abstract?
>
>
> > That is the way I read the Schema primer on this topic. You have the
>choice
> > of using the abstract, but it appears that the head element is the only
>one
> > that can have this value. I see this as being the way to control element
> > similar to complexTypes.
> >
> > ..dan
> >
> > At 04:47 PM 4/17/2003 +0800, Simon.Cox@csiro.au wrote:
> >
> > >Xerces 2.1.0 is throwing the following error for one of my schemas:
> > >
> > >"c:\dev\schemas\src\foo.xsd (121, 109) : error : For '_Bar' to be a
>member
> > >of the substitution group set of 'myns:_Foo', its {abstract} must be
>false."
> > >
> > >This appears to say that only the head of a substitution group can be
> > >abstract="true".
> > >Is this correct?  This would appear to disallow the use of some useful
> > >substitution group chains.
> > >
> > >Simon
> > >
> > >______
> > >Simon.Cox@csiro.au  CSIRO Exploration & Mining
> > >26 Dick Perry Avenue, Kensington WA 6151
> > >PO Box 1130, Bentley WA 6102  AUSTRALIA
> > >T: +61 (8) 6436 8639  F: +61 (8) 6436 8555  C: +61 (4) 0330 2672
> > >http://www.csiro.au/page.asp?type=resume&id=CoxSimon
> > >
> >
Received on Friday, 18 April 2003 11:23:54 GMT

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