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Re: Schema Component Constraint: length valid restriction

From: Kasimier Buchcik <kbuchcik@4commerce.de>
Date: Thu, 31 Mar 2005 17:15:03 +0200
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
Cc: XML-SCHEMA <xmlschema-dev@w3.org>
Message-Id: <1112282103.2038.7.camel@librax>

Hi,

On Thu, 2005-03-31 at 09:38 +0100, Henry S. Thompson wrote:
> 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.

Well, it's a shorter string :-)

> Restriction is about subsets.

True, OK... hmm, is the "fixed" property of the length facet of any
use then?

Thanks & regards,

Kasimier
Received on Thursday, 31 March 2005 15:15:14 GMT

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