Re: [xsl] How to check an element's type against an XSD simpleType and skip that element if it does not conform to the simpleType?

[Martin Honnen <Martin.Honnen@xxxxxx>]

Costello, Roger L. wrote:
> Michael Kay wrote:
>
> > Unfortunately schema-aware processing in XQuery and XSLT
> > doesn't give you this capability.
>
> Is there a workaround?
>
> Is there is no way for an XSLT program to express: "Hey, validate xyz against the XML Schema and if xyz is not schema-valid then discard it." No way to express that?

I think what you can do is not to validate the input XML but to import a 
schema and then you can write checks using e.g.
  foo castable as someType
to filter out valid or invalid items.

So with AltovaXML, when I process the  input

<BookStore xmlns="http://www.books.org";>
        <Book>
                <Title>My Life and Times</Title>
                <Author>Paul McCartney</Author>
                <Date>1998</Date>
                <ISBN>xxx1-56592-235-2</ISBN>
                <Publisher>McMillan Publishing</Publisher>
        </Book>
        <Book>
          <Title>Killing Time</Title>
          <ISBN>1-12345-123-1</ISBN>
        </Book>
</BookStore>

with the XSLT

<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
               xmlns:bk="http://www.books.org";
               exclude-result-prefixes="bk"
               version="2.0">

    <xsl:output method="xml"/>

    <xsl:import-schema namespace="http://www.books.org";
                       schema-location="test2013071602.xsd"/>

    <xsl:template match="/">
        <BookISBNs>
            <xsl:for-each select="/bk:BookStore/bk:Book[bk:ISBN 
castable as bk:ISBN-type]">
                <ISBN><xsl:value-of select="bk:ISBN"/></ISBN>
            </xsl:for-each>
        </BookISBNs>
    </xsl:template>

</xsl:transform>

where the schema is

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema";
            targetNamespace="http://www.books.org";
            xmlns="http://www.books.org";
            elementFormDefault="qualified">

    <xsd:element name="BookStore">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element ref="Book" minOccurs="0" 
maxOccurs="unbounded"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <xsd:element name="Book">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element ref="Title"/>
                <xsd:element ref="Author"/>
                <xsd:element ref="Date"/>
                <xsd:element ref="ISBN"/>
                <xsd:element ref="Publisher"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <xsd:element name="Title" type="xsd:string"/>
    <xsd:element name="Author" type="xsd:string"/>
    <xsd:element name="Date" type="xsd:string"/>
    <xsd:element name="ISBN" type="ISBN-type"/>
    <xsd:element name="Publisher" type="xsd:string"/>

    <xsd:simpleType name="ISBN-type">
        <xsd:restriction base="xsd:string">
            <xsd:pattern 
value="\d{1}-\d{5}-\d{3}-\d{1}|\d{1}-\d{3}-\d{5}-\d{1}|\d{1}-\d{2}-\d{6}-\d{1}"/> 

        </xsd:restriction>
    </xsd:simpleType>

</xsd:schema>

then I get the result

<BookISBNs><ISBN>1-12345-123-1</ISBN></BookISBNs>

So that way you can do some type checking against the schema type 
although the XML input you process is not being validated as a complete 
document.