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Re: Attribute Default Value

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 22 Nov 2001 13:21:32 +0000
To: zongaro@ca.ibm.com
Cc: www-xml-schema-comments@w3.org
Message-ID: <f5b1yirym8z.fsf@cogsci.ed.ac.uk>
zongaro@ca.ibm.com writes:

> Hello,
> 
>      According to 3.4.5 "Complex Type Definition Information Set 
> Contributions" of "XML Schema:  Structures" [1]
> 
> For each attribute use in the {attribute uses} whose {required} is false and whose {value constraint} is not ·absent· but whose {attribute declaration} does not match one of the attribute information items in the element 
> information item's [attributes] as per clause 3.1 of Element Locally Valid (Complex Type) (§3.4.4) above, the post-schema-validation infoset has an attribute information 
> item whose properties are as below added to the [attributes] of the element information item. 
> 
> 
> The section goes on to list the properties for such an attribute 
> information item as [local name], [namespace name], [schema normalized 
> value], [schema default], [validation context], [validity], [validation 
> attempted] and [schema specified].  In addition, such an attribute has 
> [type definition] and [member type definition] properties as appropriate.
> 
>      Attribute information items, as described in 2.3 of "XML Information 
> Set" [2], have the properties [namespace name], [local name], [prefix], 
> [normalized value], [specified], [attribute type], [references] and [owner 
> element].  The first two of these properties are mentioned for the 
> attribute information items described by 3.4.5 of Structures, but what of 
> the remaining six properties?
> 
>      The introduction of XML InfoSet Recommendation [3] states that some 
> properties may have the value unknown or the value no value, which are distinct from all other values.  It's not clear whether each 
> of the six properties of an attribute information item described in [2] 
> but not mentioned in [1] has the value unknown, the value no value, or just isn't a property of such an attribute information item.

The latter -- no such property supplied.

>      If the six absent properties aren't actually properties of such an 
> attribute information item, then I believe they should be described as 
> some other kind of information item, rather than referring to the 
> definition provided in the XML InfoSet Recommendation.

I think it's OK to be an Info Item and not have all the properties
named for that kind of Item in the Infoset REC.  There are no
'required' properties any more -- just properties whose names you
should use to supply the specified information.  Since we _can't_
supply the information named by the "missing six", we don't.

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, 22 November 2001 08:20:33 GMT

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