Re: [xml] xml:lang iso639-2 / rfc3066 / rfc 1766 obsolete

[Daniel Veillard <veillard redhat com>]

On Thu, Dec 13, 2007 at 03:12:30PM +0100, Friedbert Wekerle wrote:
> Dear Daniel,

  please keep discussion on list !

> thank You for your immediate response.
> 
> I'm processing extern-data. In this data 
> the attribute xml:lang is often used; 
> before importing these data into our database,
> I check them with Your appreciated tool
> libxml via perl (linux).
> 
> libxml incriminates the value "grc" of the attribute "xml:lang":
> 
> "...lang': 'grc' is not a valid value of the local union
> type."
> 
> It does not incriminate the value "en".
> 
> As a simplified xsd/xml You can see that behavior
> with the following example:
> 
> a.xsd
> =============================================================
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";>
> <xs:import namespace="http://www.w3.org/XML/1998/namespace"; schemaLocation="http://www.w3.org/2001/xml.xsd"/>
> 
> <xs:attributeGroup name="i18n">
>   <xs:attribute ref="xml:lang"/>
> </xs:attributeGroup>
> 
> <xs:complexType name="A">
>   <xs:sequence>
>     <xs:element name="P" type="xs:string"/>
>   </xs:sequence>
>   <xs:attributeGroup ref="i18n"/>
> </xs:complexType>
> 
> <xs:element name="A"/>
> 
> </xs:schema>
> =============================================================

  You are using a Schemas, that wasn't explicitely stated in the
initial report (see http://xmlsoft.org/bugs.html I have no cristal ball!)
> a.xml
> =============================================================
> <?xml version="1.0" encoding="ISO-8859-1" ?>
> <A xml:lang="grc">
>   <P>xxx</P>
> </A>
> =============================================================
> 
> then: (linux or win):libxml2-2.6.30.win32\bin\xmllint -noout --schema a.xsd a.xml
> produces the errormessage.
> 
> My question was: how can I treat xmllint/libxml tolerating "grc" as an
> valid attributValue of "xml:lang"?

  Your schemas use http://www.w3.org/2001/xml.xsd , which in turn uses
xs:language which uses to reference [RFC 1766] and now references [RFC 3066] 
  In XML-1.0 we dropped any test of the values of xml:lang because in practice
this didn't worked well (because the set changes and this does not change 
the resulting data being provided to the application)

  I can't say I will have time to update the libxml2 XSD datatype to 
reflect the new RFC reference, if someone wants to do it, go ahead !

Daniel

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