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Re: Is this valid?

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 30 Nov 2000 12:17:23 +0000
To: "David E. Cleary" <davec@progress.com>
Cc: <xmlschema-dev@w3.org>
Message-ID: <f5belzt4pt8.fsf@cogsci.ed.ac.uk>
"David E. Cleary" <davec@progress.com> writes:

> This is using the April 7 syntax:
> 
> 	<element name = "XMI.difference">
> 		<complexType content = "elementOnly">
> 			<choice minOccurs = "0" maxOccurs = "unbounded">
> 				<element ref = "XMI.difference"/>
> 				<element ref = "XMI.delete"/>
> 				<element ref = "XMI.add"/>
> 				<element ref = "XMI.replace"/>
> 			</choice>
> 			<attributeGroup ref = "XMI.element.att"/>
> 			<attributeGroup ref = "XMI.link.att"/>
> 		</complexType>
> 	</element>
> 
> This definition was created by XML Authority by converting a DTD. It has an
> element declaration that includes a reference to itself. This causes our
> tool to loop until it blows up. The April 7 XSV doesn't complain. Is it
> legal to do this?

It's fine.  It reconstructs

 <!ELEMENT x (x|y|z)>

which it would be very odd to rule out, to say nothing of violating
our Requirements document.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Thursday, 30 November 2000 07:17:31 GMT

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