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RE: Inheritance of "mixed"

From: Michael Kay <mhk@mhk.me.uk>
Date: Fri, 17 Sep 2004 11:53:53 +0100
To: "'Henry S. Thompson'" <ht@inf.ed.ac.uk>
Cc: <xmlschema-dev@w3.org>
Message-ID: <E1C8GNq-00071k-UQ@frink.w3.org>

OK, thanks, I see it now. In my example, the "effective content" of the
derived type is empty, and therefore the "effective mixed" is ineffective.

Michael Kay 


> -----Original Message-----
> From: Henry S. Thompson [mailto:ht@inf.ed.ac.uk] 
> Sent: 17 September 2004 09:52
> To: Michael Kay
> Cc: xmlschema-dev@w3.org
> Subject: Re: Inheritance of "mixed"
> 
> "Michael Kay" <mhk@mhk.me.uk> writes:
> 
> > Where a complex type A does not specify "mixed" (either on 
> the complexType
> > element or the complexContent element), and is derived by 
> extension from a
> > complex type B that specifies mixed="yes", Xerces and XSV 
> both appear to
> > treat A as allowing mixed content.
> >
> > They are presumably doing the right thing, and it seems a 
> sensible thing to
> > do, but I can't find anything in the spec that justifies 
> it. As I read the
> > rules, the "effective mixed" of A is false, and there is 
> then a violation of
> > the constraint Derivation Valid (Extension): 1.4.3.2.2.1 
> Both {content
> > type}s must be mixed or both must be element-only.
> 
> There has been some reworking of all this in the PER [1] but in
> general you're right, and XSV (2.7, anyway) reports the error in e.g.
> 
>  <xs:complexType name="b2" mixed="true">
>   <xs:sequence>
>    <xs:element name="a"/>
>   </xs:sequence>
>  </xs:complexType>
> 
>  <xs:complexType name="e6x">
>   <xs:complexContent>
>    <xs:extension base="b2">
>     <xs:sequence>
>      <xs:element name="b"/>
>     </xs:sequence>
>    </xs:extension>
>   </xs:complexContent>
>  </xs:complexType>
> 
> If either of the type defs is empty the rules are different, however
> -- was that the case in your example?
> 
> ht
> 
> [1] 
> http://www.w3.org/TR/2004/PER-xmlschema-1-20040318/structures-
> with-errata.html#declare-type
> -- 
>  Henry S. Thompson, HCRC Language Technology Group, 
> University of Edinburgh
>                      Half-time member of W3C Team
>     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 
> 131 650-4440
>             Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
>                    URL: http://www.ltg.ed.ac.uk/~ht/
> [mail really from me _always_ has this .sig -- mail without 
> it is forged spam]
> 
Received on Friday, 17 September 2004 10:54:30 UTC

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