Re: Attributes and extension

Claude Seyrat <> 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.

  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:

Received on Thursday, 4 January 2001 09:34:03 UTC