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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?


Subject: 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?
From: "Costello, Roger L." <costello@xxxxxxxxx>
Date: Tue, 16 Jul 2013 12:07:58 +0000

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?

Here is an idea: feed into the XSLT program a BookStore XML document that is
known to be schema-valid and then in the XSLT program ignore it and instead
process BookStore-v2.xml, which is input via the document() function. Below is
my attempt at this. I no longer get an error, but it doesn't give the correct
results; it just gives an empty root element (<BookISBNs/> ) Any suggestions?

---------------------------------------------------------------
     Roger's Brilliant Workaround BookStore.xsl
             (doesn't work as desired)
---------------------------------------------------------------
<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:variable name="new-BookStore" select="document('BookStore-v2.xml')"
/>

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

    <xsl:template match="/">
        <BookISBNs>
            <xsl:for-each
select="$new-BookStore/bk:BookStore/bk:Book/bk:ISBN/text()">
                <xsl:if test=". instance of bk:ISBN-type">
                    <ISBN><xsl:value-of select="."/></ISBN>
                </xsl:if>
            </xsl:for-each>
        </BookISBNs>
    </xsl:template>

</xsl:transform>


-----Original Message-----
From: Michael Kay [mailto:mike@xxxxxxxxxxxx]
Sent: Tuesday, July 16, 2013 5:49 AM
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: 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?

Unfortunately schema-aware processing in XQuery and XSLT doesn't give you this
capability. XSLT doesn't have the capability to process a PSVI that contains a
mix of valid and marked-as-invalid elements. It would be nice if it did, and
perhaps that's something for me to explore as a Saxon extension.

Michael Kay
Saxonica


On 15 Jul 2013, at 19:55, Costello, Roger L. wrote:

> Hi Folks,
>
> I would like to do schema-aware processing on this document:
>
> <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>
>        ...
> </BookStore>
>
> I have a corresponding XML Schema, which I show in its entirety at the
bottom of this message. The item of interest, however, is its simpleType for
ISBN elements:
>
>    <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>
>
> I want my XSLT program to output each ISBN in the XML document. If an ISBN
does not conform to the simpleType, then I want to skip that ISBN element and
continue processing. At the bottom of this message is the XSLT in its
entirety. The item of interest, however, is this snippet:
>
>            <xsl:for-each select="/bk:BookStore/bk:Book">
>                <xsl:if test="data(bk:ISBN) instance of bk:ISBN-type">
>                    <ISBN><xsl:value-of select="bk:ISBN"/></ISBN>
>                </xsl:if>
>            </xsl:for-each>
>
> The for-loop iterates through each Book and checks to see if the value of
its ISBN element conforms to ISBN-type; if it doesn't conform, then it skips
that ISBN and goes to the next Book.
>
> In the XML document shown above, the Book element has an ISBN
(xxx1-56592-235-2) that is not valid, so I expect my XSLT program to skip it.
>
> However, that is not happening. I get this error message:
>
>    The content "xxx1-56592-235-2" of element <ISBN> does not
>    match the required simple type. Value "xxx1-56592-235-2"
>    contravenes the pattern facet "\d{1}-\d{5}-\d{3}-\d{1}|\d{1}-..."
>    of the type ISBN-type
>
> What am I doing wrong please?
>
> /Roger
> -----------------------------------------------------------
>       BookStore.xsl
> -----------------------------------------------------------
> <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="BookStore.xsd"/>
>
>    <xsl:template match="/">
>        <BookISBNs>
>            <xsl:for-each select="/bk:BookStore/bk:Book">
>                <xsl:if test="data(bk:ISBN) instance of bk:ISBN-type">
>                    <ISBN><xsl:value-of select="bk:ISBN"/></ISBN>
>                </xsl:if>
>            </xsl:for-each>
>        </BookISBNs>
>    </xsl:template>
>
> </xsl:transform>
>
> -----------------------------------------------------------
>       BookStore.xsd
> -----------------------------------------------------------
> <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>


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