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Re: Schema Component Constraint: length valid restriction

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 31 Mar 2005 09:38:57 +0100
To: Kasimier Buchcik <kbuchcik@4commerce.de>
Cc: XML-SCHEMA <xmlschema-dev@w3.org>
Message-ID: <f5b8y44ciqm.fsf@erasmus.inf.ed.ac.uk>

Kasimier Buchcik <kbuchcik@4commerce.de> writes:

> "Length valid restriction" says: 
> "It is an ·error· if length is among the members of {facets} of {base
> type definition} and {value} is not equal to the {value} of the parent
> length."
>
> Xerces 2.6.2 and XSV 2.7 seem to handle this constraint differently.
>
> Example:
> <xsd:simpleType name="fooType">
>   <xsd:restriction>
>     <xsd:simpleType>
>       <xsd:restriction base="xsd:string">
>         <xsd:length value="2"/>
>       </xsd:restriction>
>     </xsd:simpleType>			
>     <xsd:length value="1"/>
>   </xsd:restriction>
> </xsd:simpleType> 
>
> While XSV does not report an error

XSV is sloppy -- er, that's a bug.


> Xerces reports: "(Error) length-valid-restriction: Error for type
> 'fooType'. The value of length = '1' must be = the value of that of
> the base type '2'."
>
> Whom to follow here?

Xerces.

> If this is not a bug in the spec, what is the intention of disallowing
> to restrict the length of e.g. a string?

Strings of length 1 are not a subset of strings of length 2.
Restriction is about subsets.

ht
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
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            Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
                   URL: http://www.ltg.ed.ac.uk/~ht/
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Received on Thursday, 31 March 2005 08:39:07 GMT

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