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Re: Attributes and extension

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 04 Jan 2001 14:33:59 +0000
To: Claude Seyrat <cseyrat@acland.fr>
Cc: www-xml-schema-comments@w3.org
Message-ID: <f5belyjidyg.fsf@cogsci.ed.ac.uk>
Claude Seyrat <cseyrat@acland.fr> writes:

> Dear All,
> 
> In case of an extension can we redefine an attribute in order to 
> change its use or default value ?
> 
> In the proposed recommendations :
> 
> Constraint on Schemas: Derivation Valid (Extension) 
> If the {derivation method} is extension: 
> 1.1 If the {base type definition} is a complex type definition: 
>   1.1.1 The {final} of the {base type definition} must not contain 
>         extension 
>   1.1.2 
>              Its {attribute use pairs} must be a subset of the 
>              {attribute use pairs} of the complex type definition 
>              itself, that is, for every attribute use pair in the 
>              {attribute use pairs} of the {base type definition}, 
>              there must be a pair in the {attribute use pairs} of 
>              the complex type definition itself whose attribute 
>              declaration has the same {name}, {target namespace} and 
>              {type definition} as its attribute declaration; 
> 
> 		^^^^^^^^^^^ does it mean that we can change its 
>                use and default value ?

No, that is not allowed, and the spec. should make this clear -- the
bug arose during the introduction of the distinction between attribute 
use pairs and attribute declarations.

Thanks for spotting this.

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, 4 January 2001 09:34:03 GMT

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