Re: [xsl] How to compare two QName values in an XML Schema?

[David Carlisle <davidc@xxxxxxxxx>]

On 08/04/2011 17:00, Costello, Roger L. wrote:
> Hi Folks,
>
> Below is an XML Schema, containing two simpleTypes. The second one references the first.
>
> I want an XPath expression that compares the second simpleType's reference to the name of the first simpleType:
>
>
>      /xs:schema/xs:simpleType[1]/@name
>        eq
>      /xs:schema/xs:simpleType[2]/xs:restriction/@base
>
>
> That returns False. I want it to return True.
>
> I figured the reason it's returning False is because it is comparing the string "elev:BostonAreaSurfaceElevation" against the string "EarthSurfaceElevation". Yes?

one way is to use a schema aware xpath engine, if the two attributes are 
schema typed as QNames they will be compared as such.

otherwise you can extract the local name and uri associated with the 
prefix using in-scope-prefixes 9or the namespace axis if that is supported)

David


> I want it to do a comparison of QNames, not strings. So I type-cast the values:
>
>
>      xs:QName(/xs:schema/xs:simpleType[1]/@name)
>         eq
>      xs:QName(/xs:schema/xs:simpleType[2]/xs:restriction/@base)
>
>
> But that gave me this error:
>
>     Casting from xs:unTypedAtomic to xs:QName can never succeed.
>
> Why?
>
> What's the correct way to do the comparison?
>
> ---------------------------------------------------------
> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema";
>              targetNamespace="http://www.elevation.org";
>              xmlns:elev="http://www.elevation.org";
>              elementFormDefault="qualified">
>
>      <xsd:simpleType name= "EarthSurfaceElevation">
>          <xsd:restriction base="xsd:integer">
>              <xsd:minInclusive value="-1290"/>
>              <xsd:maxInclusive value="29035"/>
>          </xsd:restriction>
>      </xsd:simpleType>
>
>      <xsd:simpleType name= "BostonAreaSurfaceElevation">
>          <xsd:restriction base="elev:EarthSurfaceElevation">
>              <xsd:minInclusive value="0"/>
>              <xsd:maxInclusive value="120"/>
>          </xsd:restriction>
>      </xsd:simpleType>
>
> </xsd:schema>
> ---------------------------------------------------------
>
> /Roger
>
>
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