Creating the Result Tree
There are several more elements that can be used in creating the result
tree:
-
<xsl:attribute-set>
-
Names a collection of attributes for use as a set
-
<xsl:comment>
-
Creates an XML comment (<!-- like this -->) in the result tree
-
<xsl:processing-instruction>
-
Creates an XML processing instruction (<?pitarget like="this"?>)
in the result tree
Keys
The ID/IDREF mechanism for locating elements in XML documents has been
generalized in XSL to the notion of keys.
Declaring keys gives the stylesheet processor an indication of what
elements should be cached for fast access.
Key Example
Example 27. keys.xsl
<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:key name="bibkey" match="//biblio/bib" use="@abbrev"/>
<xsl:template match="doc">
<xsl:apply-templates/>
</xsl:template>
<xsl:template match="biblio">
<!-- suppressed -->
</xsl:template>
<xsl:template match="para">
<xsl:apply-templates/>
</xsl:template>
<xsl:template match="bibref">
<xsl:variable name="bib" select="key('bibkey',string(.))"/>
<xsl:choose>
<xsl:when test="$bib">
<i><xsl:apply-templates select="$bib"/></i>
</xsl:when>
<xsl:otherwise>
<b>NO BIB FOR <xsl:apply-templates/></b>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template match="bib">
<xsl:apply-templates/>
</xsl:template>
</xsl:stylesheet>
Example 28. keys.xml
<doc>
<para>See <bibref>xyzzy</bibref>.</para>
<biblio>
<bib abbrev="xyzzy">The Great Grue</bib>
<bib abbrev="abcde">That Alphabet Song</bib>
</biblio>
</doc>
Example 29. keys.html
<?xml version="1.0" encoding="utf-8" ?>
See <i>The Great Grue</i>.
Extending XSLT
-
Extension Functions
-
Extension Elements
-
<xsl:fallback>
Extension Examples
These examples are from James' XT distribution:
Example 30. ext-func.xsl
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:date="http://www.jclark.com/xt/java/java.util.Date">
<xsl:template match="/">
<html>
<xsl:if test="function-available('date:to-string')
and function-available('date:new')">
<p><xsl:value-of select="date:to-string(date:new())"/></p>
</xsl:if>
</html>
</xsl:template>
</xsl:stylesheet>
Example 31. ext-elem.xsl
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0"
xmlns:xt="http://www.jclark.com/xt"
extension-element-prefixes="xt">
<xsl:output method="text"/>
<xsl:template match="file">
<xt:document href="{@name}" method="xml">
<xsl:fallback>This should not happen.</xsl:fallback>
<xsl:apply-templates mode="copy"/>
</xt:document>
<xsl:text>Created file </xsl:text>
<xsl:value-of select="@name"/>
<xsl:text>
</xsl:text>
</xsl:template>
<xsl:template mode="copy" match="*|@*">
<xsl:copy>
<xsl:apply-templates select="@*" mode="copy"/>
<xsl:apply-templates select="node()" mode="copy"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Nested list example
<?xml version="1.0"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:fo="http://www.w3.org/1999/XSL/Format">
<xsl:template match="doc">
<fo:block>
<xsl:apply-templates/>
</fo:block>
</xsl:template>
<xsl:template match="p">
<fo:block>
<xsl:apply-templates/>
</fo:block>
</xsl:template>
<xsl:template match="list">
<fo:list-block space-before="10pt"
provisional-distance-between-starts="3pc"
provisional-label-separation="1pc">
<xsl:apply-templates/>
</fo:list-block>
</xsl:template>
<xsl:template match="list//list">
<fo:list-block space-before="8pt"
provisional-distance-between-starts="3pc"
provisional-label-separation="1pc"
start-indent="3pc">
<xsl:apply-templates/>
</fo:list-block>
</xsl:template>
<xsl:template match="list/item">
<fo:list-item space-before="6pt">
<fo:list-item-label>
<fo:block>
<xsl:number count="item" format="1."/>
</fo:block>
</fo:list-item-label>
<fo:list-item-body>
<fo:block>
<xsl:apply-templates/>
</fo:block>
</fo:list-item-body>
</fo:list-item>
</xsl:template>
<xsl:template match="list//list/item" priority="1">
<fo:list-item space-before="6pt">
<fo:list-item-label>
<fo:block>
<xsl:number count="item" format="a."/>
</fo:block>
</fo:list-item-label>
<fo:list-item-body>
<fo:block>
<xsl:apply-templates/>
</fo:block>
</fo:list-item-body>
</fo:list-item>
</xsl:template>
<xsl:template match="list//list//list/item" priority="2">
<fo:list-item space-before="6pt">
<fo:list-item-label>
<fo:block>
<xsl:number count="item" format="i."/>
</fo:block>
</fo:list-item-label>
<fo:list-item-body>
<fo:block>
<xsl:apply-templates/>
</fo:block>
</fo:list-item-body>
</fo:list-item>
</xsl:template>
</xsl:stylesheet>
Other formatting objects
