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Re: Current Status of XSV: shadowing of elementFormDefault

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 31 Mar 2001 11:30:42 +0100
To: "Roger L. Costello" <costello@mitre.org>
Cc: xmlschema-dev@w3.org, jeffrafter@earthlink.net
Message-ID: <f5bvgoqdyct.fsf@cogsci.ed.ac.uk>
"Roger L. Costello" <costello@mitre.org> writes:

> "Henry S. Thompson" wrote:
> > 
> > Other way 'round -- the declaration in the include_d_ schema overrides
> > that in the includ_ing_ schema.  Sorry if 'shadow' was a misleading
> > word to use.
> Let me make absolutely certain that I understand this.  I think that to
> avoid any ambiguity let's consider an example.  
> Example.  Suppose that I create a Camera schema, and it includes three
> schemas - Nikon.xsd, Olympus.xsd, and Pentex.xsd. 
> Camera.xsd
>    elementFormDefault="qualified"
>    include Nikon.xsd, Olympus.xsd, Pentex.xsd
> Nikon.xsd
>    elementFormDefault="unqualified"
> Olympus.xsd
>   elementFormDefault="qualified"
> Pentex.xsd
>   elementFormDefault="unqualified"
> > the declaration in the include_d_ schema overrides that in 
> > the includ_ing_ schema. 
> We have three schemas being included, each with different values for
> elementFormDefault (unqualified, qualified, unqualified, respectively). 
> Which one will override Camera's elementFormDefault?
> I believe that you really mean that Camera's elementFormDefault
> overrides the elementFormDefault values found in Nikon.xsd, Olympus.xsd,
> or Pentex.xsd.  Correct?  /Roger

Absolutely not.  Local decls from Nikon and Pentex (sic) will validate 
unqualified elements in documents which identify Camera as their
schema, local decls from Olympus will validate qualified elements
ditto, and local decls in types actually defined in Camera itself will 
validate qualified elements in all circumstances.

It's a locality point -- when you look at a declaration, you can
_always_ tell by looking only at its 'form' attribute and the eFD of
_its_ containing schema element whether it validates qualified or
unqualfied items.

  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 Saturday, 31 March 2001 05:30:45 UTC

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