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RE: Final and Block on Element

From: Priscilla Walmsley <priscilla@walmsley.com>
Date: Thu, 23 Aug 2001 09:31:58 -0400
To: "'Neil Bradley'" <neil.bradley@rubus.com>, <xmlschema-dev@w3.org>
Message-ID: <012401c12bd8$180537d0$1ab0153f@xmls>
Hello,

The "final" attribute on an element determines whether it can be used as the
head of a substitution group.

The "block" attribute on an element determines whether it can be substituted
in the instance:
- If the value is "extension" and/or "restriction" it is similar to the
block attribute on complex types. No type substitution is allowed for that
element (via xsi:type).
- If the value is "substitution" it cannot be substituted with members of a
substitution group.

The distinction between final="#all" and block="substitution" is subtle.
The final attribute has to do with what is allowed in the schema, while the
block attribute covers what is allowed in the instance.


Priscilla

-----------------------------------------------------------
Priscilla Walmsley                   priscilla@walmsley.com
Architect, Vitria Technology          http://www.vitria.com
Author, Definitive XML Schema  (Prentice Hall, Dec. 2001)
-----------------------------------------------------------

> -----Original Message-----
> From: xmlschema-dev-request@w3.org
> [mailto:xmlschema-dev-request@w3.org]On Behalf Of Neil Bradley
> Sent: Wednesday, August 22, 2001 4:34 AM
> To: 'xmlschema-dev@w3.org'
> Subject: Final and Block on Element
>
>
>
> > I know this has been asked before, but I did not see an
> answer. Why are
> > there Final and Block attributes on the Element element?
> >
> > Neil.
> >
>
>
>
Received on Thursday, 23 August 2001 09:31:19 GMT

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