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tdelibs/kdoctools/docbook/xsl/lib/lib.xweb

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<book xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<bookinfo>
<title>XSL Library Template Reference</title>
<releaseinfo role="cvs">$Id$
</releaseinfo>
<corpauthor>DocBook Open Repository Team</corpauthor>
<copyright>
<year>1999</year>
<year>2000</year>
<year>2001</year>
<year>2002</year>
<holder>Norman Walsh</holder>
</copyright>
</bookinfo>
<preface><title>Introduction</title>
<para>This is technical reference documentation for the DocBook XSL
Stylesheets; it documents (some of) the parameters, templates, and
other elements of the stylesheets.</para>
<para>This is not intended to be <quote>user</quote> documentation.
It is provided for developers writing customization layers for the
stylesheets, and for anyone who's interested in <quote>how it
works</quote>.</para>
<para>Although I am trying to be thorough, this documentation is known
to be incomplete. Don't forget to read the source, too :-)</para>
</preface>
<reference>
<title>General Library Templates</title>
<refentry id="dot.count">
<refnamediv>
<refname>dot.count</refname>
<refpurpose>Returns the number of <quote>.</quote> characters in a string</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<programlisting><src:fragment id='dot.count.frag'>
<xsl:template name="dot.count">
<!-- Returns the number of "." characters in a string -->
<xsl:param name="string"></xsl:param>
<xsl:param name="count" select="0"/>
<xsl:choose>
<xsl:when test="contains($string, '.')">
<xsl:call-template name="dot.count">
<xsl:with-param name="string" select="substring-after($string, '.')"/>
<xsl:with-param name="count" select="$count+1"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$count"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="copy-string">
<refnamediv>
<refname>copy-string</refname>
<refpurpose>Returns <quote>count</quote> copies of a string</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<programlisting><src:fragment id='copy-string.frag'>
<xsl:template name="copy-string">
<!-- returns 'count' copies of 'string' -->
<xsl:param name="string"></xsl:param>
<xsl:param name="count" select="0"/>
<xsl:param name="result"></xsl:param>
<xsl:choose>
<xsl:when test="$count>0">
<xsl:call-template name="copy-string">
<xsl:with-param name="string" select="$string"/>
<xsl:with-param name="count" select="$count - 1"/>
<xsl:with-param name="result">
<xsl:value-of select="$result"/>
<xsl:value-of select="$string"/>
</xsl:with-param>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$result"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ====================================================================== -->
<refentry id="string.subst">
<refnamediv>
<refname>string.subst</refname>
<refpurpose>Substitute one text string for another in a string</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>string.subst</function> template replaces all
occurances of <parameter>target</parameter> in <parameter>string</parameter>
with <parameter>replacement</parameter> and returns the result.
</para>
<programlisting><src:fragment id='string.subst.frag'>
<xsl:template name="string.subst">
<xsl:param name="string"></xsl:param>
<xsl:param name="target"></xsl:param>
<xsl:param name="replacement"></xsl:param>
<xsl:choose>
<xsl:when test="contains($string, $target)">
<xsl:variable name="rest">
<xsl:call-template name="string.subst">
<xsl:with-param name="string"
select="substring-after($string, $target)"/>
<xsl:with-param name="target" select="$target"/>
<xsl:with-param name="replacement" select="$replacement"/>
</xsl:call-template>
</xsl:variable>
<xsl:value-of select="concat(substring-before($string, $target),
$replacement,
$rest)"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$string"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="xpointer.idref">
<refnamediv>
<refname>xpointer.idref</refname>
<refpurpose>Extract IDREF from an XPointer</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>xpointer.idref</function> template returns the
ID portion of an XPointer which is a pointer to an ID within the current
document, or the empty string if it is not.</para>
<para>In other words, <function>xpointer.idref</function> returns
<quote>foo</quote> when passed either <literal>#foo</literal>
or <literal>#xpointer(id('foo'))</literal>, otherwise it returns
the empty string.</para>
<programlisting><src:fragment id='xpointer.idref.frag'>
<xsl:template name="xpointer.idref">
<xsl:param name="xpointer">http://...</xsl:param>
<xsl:choose>
<xsl:when test="starts-with($xpointer, '#xpointer(id(')">
<xsl:variable name="rest" select="substring-after($xpointer, '#xpointer(id(')"/>
<xsl:variable name="quote" select="substring($rest, 1, 1)"/>
<xsl:value-of select="substring-before(substring-after($xpointer, $quote), $quote)"/>
</xsl:when>
<xsl:when test="starts-with($xpointer, '#')">
<xsl:value-of select="substring-after($xpointer, '#')"/>
</xsl:when>
<!-- otherwise it's a pointer to some other document -->
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="length-magnitude">
<refnamediv>
<refname>length-magnitude</refname>
<refpurpose>Return the unqualified dimension from a length specification</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>length-magnitude</function> template returns the
unqualified length ("20" for "20pt") from a dimension.
</para>
<programlisting><src:fragment id='length-magnitude.frag'>
<xsl:template name="length-magnitude">
<xsl:param name="length" select="'0pt'"/>
<xsl:choose>
<xsl:when test="string-length($length) = 0"/>
<xsl:when test="substring($length,1,1) = '0'
or substring($length,1,1) = '1'
or substring($length,1,1) = '2'
or substring($length,1,1) = '3'
or substring($length,1,1) = '4'
or substring($length,1,1) = '5'
or substring($length,1,1) = '6'
or substring($length,1,1) = '7'
or substring($length,1,1) = '8'
or substring($length,1,1) = '9'
or substring($length,1,1) = '.'">
<xsl:value-of select="substring($length,1,1)"/>
<xsl:call-template name="length-magnitude">
<xsl:with-param name="length" select="substring($length,2)"/>
</xsl:call-template>
</xsl:when>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="length-units">
<refnamediv>
<refname>length-units</refname>
<refpurpose>Return the units from a length specification</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>length-units</function> template returns the
units ("pt" for "20pt") from a length. If no units are supplied on the
length, the <parameter>defauilt.units</parameter> are returned.</para>
<programlisting><src:fragment id='length-units.frag'>
<xsl:template name="length-units">
<xsl:param name="length" select="'0pt'"/>
<xsl:param name="default.units" select="'px'"/>
<xsl:variable name="magnitude">
<xsl:call-template name="length-magnitude">
<xsl:with-param name="length" select="$length"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="units">
<xsl:value-of select="substring($length, string-length($magnitude)+1)"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="$units = ''">
<xsl:value-of select="$default.units"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$units"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="length-spec">
<refnamediv>
<refname>length-spec</refname>
<refpurpose>Return a fully qualified length specification</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>length-spec</function> template returns the
qualified length from a dimension. If an unqualified length is given,
the <parameter>default.units</parameter> will be added to it.
</para>
<programlisting><src:fragment id='length-spec.frag'>
<xsl:template name="length-spec">
<xsl:param name="length" select="'0pt'"/>
<xsl:param name="default.units" select="'px'"/>
<xsl:variable name="magnitude">
<xsl:call-template name="length-magnitude">
<xsl:with-param name="length" select="$length"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="units">
<xsl:value-of select="substring($length, string-length($magnitude)+1)"/>
</xsl:variable>
<xsl:value-of select="$magnitude"/>
<xsl:choose>
<xsl:when test="$units='cm'
or $units='mm'
or $units='in'
or $units='pt'
or $units='pc'
or $units='px'
or $units='em'">
<xsl:value-of select="$units"/>
</xsl:when>
<xsl:when test="$units = ''">
<xsl:value-of select="$default.units"/>
</xsl:when>
<xsl:otherwise>
<xsl:message>
<xsl:text>Unrecognized unit of measure: </xsl:text>
<xsl:value-of select="$units"/>
<xsl:text>.</xsl:text>
</xsl:message>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="length-in-points">
<refnamediv>
<refname>length-in-points</refname>
<refpurpose>Returns the size, in points, of a specified length</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>length-in-points</function> template converts a length
specification to points and returns that value as an unqualified
number.
</para>
<caution>
<para>There is no way for the template to infer the size of an
<literal>em</literal>. It relies on the default <parameter>em.size</parameter>
which is initially <literal>10</literal> (for 10pt).</para>
<para>Similarly, converting pixesl to points relies on the
<parameter>pixels.per.inch</parameter> parameter which is initially
<literal>90</literal>.
</para>
</caution>
<programlisting><src:fragment id='length-in-points.frag'>
<xsl:template name="length-in-points">
<xsl:param name="length" select="'0pt'"/>
<xsl:param name="em.size" select="10"/>
<xsl:param name="pixels.per.inch" select="90"/>
<xsl:variable name="magnitude">
<xsl:call-template name="length-magnitude">
<xsl:with-param name="length" select="$length"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="units">
<xsl:value-of select="substring($length, string-length($magnitude)+1)"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="$units = 'pt'">
<xsl:value-of select="$magnitude"/>
</xsl:when>
<xsl:when test="$units = 'cm'">
<xsl:value-of select="$magnitude div 2.54 * 72.0"/>
</xsl:when>
<xsl:when test="$units = 'mm'">
<xsl:value-of select="$magnitude div 25.4 * 72.0"/>
</xsl:when>
<xsl:when test="$units = 'in'">
<xsl:value-of select="$magnitude * 72.0"/>
</xsl:when>
<xsl:when test="$units = 'pc'">
<xsl:value-of select="$magnitude * 12.0"/>
</xsl:when>
<xsl:when test="$units = 'px'">
<xsl:value-of select="$magnitude div $pixels.per.inch * 72.0"/>
</xsl:when>
<xsl:when test="$units = 'em'">
<xsl:value-of select="$magnitude * $em.size"/>
</xsl:when>
<xsl:otherwise>
<xsl:message>
<xsl:text>Unrecognized unit of measure: </xsl:text>
<xsl:value-of select="$units"/>
<xsl:text>.</xsl:text>
</xsl:message>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="pi-attribute">
<refnamediv>
<refname>pi-attribute</refname>
<refpurpose>Extract a pseudo-attribute from a PI</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>pi-attribute</function> template extracts a pseudo-attribute
from a processing instruction. For example, given the PI
<quote><literal>&lt;?foo bar="1" baz='red'?&gt;</literal></quote>,</para>
<programlisting><![CDATA[<xsl:call-template name="pi-attribute">
<xsl:with-param name="pis" select="processing-instruction('foo')"/>
<xsl:with-param name="attribute" select="'baz'"/>
</xsl:call-template>]]></programlisting>
<para>will return <quote>red</quote>. This template returns the first matching
attribute that it finds. Presented with processing instructions that
contain badly formed pseudo-attributes (missing or unbalanced quotes,
for example), the template may silently return erroneous results.</para>
<programlisting><src:fragment id='pi-attribute.frag'>
<xsl:template name="pi-attribute">
<xsl:param name="pis" select="processing-instruction('BOGUS_PI')"/>
<xsl:param name="attribute">filename</xsl:param>
<xsl:param name="count">1</xsl:param>
<xsl:choose>
<xsl:when test="$count>count($pis)">
<!-- not found -->
</xsl:when>
<xsl:otherwise>
<xsl:variable name="pi">
<xsl:value-of select="$pis[$count]"/>
</xsl:variable>
<xsl:variable name="pivalue">
<xsl:value-of select="concat(' ', normalize-space($pi))"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="contains($pivalue,concat(' ', $attribute, '='))">
<xsl:variable name="rest" select="substring-after($pivalue,concat(' ', $attribute,'='))"/>
<xsl:variable name="quote" select="substring($rest,1,1)"/>
<xsl:value-of select="substring-before(substring($rest,2),$quote)"/>
</xsl:when>
<xsl:otherwise>
<xsl:call-template name="pi-attribute">
<xsl:with-param name="pis" select="$pis"/>
<xsl:with-param name="attribute" select="$attribute"/>
<xsl:with-param name="count" select="$count + 1"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="lookup.key">
<refnamediv>
<refname>lookup.key</refname>
<refpurpose>Retrieve the value associated with a particular key in a table</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>Given a table of space-delimited key/value pairs,
the <function>lookup.key</function> template extracts the value associated
with a particular key.</para>
<programlisting><src:fragment id='lookup.key.frag'>
<xsl:template name="lookup.key">
<xsl:param name="key" select="''"/>
<xsl:param name="table" select="''"/>
<xsl:if test="contains($table, ' ')">
<xsl:choose>
<xsl:when test="substring-before($table, ' ') = $key">
<xsl:variable name="rest" select="substring-after($table, ' ')"/>
<xsl:choose>
<xsl:when test="contains($rest, ' ')">
<xsl:value-of select="substring-before($rest, ' ')"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$rest"/>
</xsl:otherwise>
</xsl:choose>
</xsl:when>
<xsl:otherwise>
<xsl:call-template name="lookup.key">
<xsl:with-param name="key" select="$key"/>
<xsl:with-param name="table"
select="substring-after(substring-after($table,' '), ' ')"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:if>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="xpath.location">
<refnamediv>
<refname>xpath.location</refname>
<refpurpose>Calculate the XPath child-sequence to the current node</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>xpath.location</function> template calculates the
absolute path from the root of the tree to the current element node.
</para>
<programlisting><src:fragment id='xpath.location.frag'>
<xsl:template name="xpath.location">
<xsl:param name="node" select="."/>
<xsl:param name="path" select="''"/>
<xsl:variable name="next.path">
<xsl:value-of select="local-name($node)"/>
<xsl:if test="$path != ''">/</xsl:if>
<xsl:value-of select="$path"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="$node/parent::*">
<xsl:call-template name="xpath.location">
<xsl:with-param name="node" select="$node/parent::*"/>
<xsl:with-param name="path" select="$next.path"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:text>/</xsl:text>
<xsl:value-of select="$next.path"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<!-- ================================================================== -->
<refentry id="comment-escape-string">
<refnamediv>
<refname>comment-escape-string</refname>
<refpurpose>Prepare a string for inclusion in an XML comment</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>comment-escape-string</function> template returns a string
that has been transformed so that it can safely be output as an XML comment.
Internal occurrences of "--" will be replaced with "- -" and a leading and/or
trailing space will be added to the string, if necessary.</para>
<programlisting><src:fragment id='comment-escape-string'>
<xsl:template name="comment-escape-string">
<xsl:param name="string" select="''"/>
<xsl:if test="starts-with($string, '-')">
<xsl:text> </xsl:text>
</xsl:if>
<xsl:call-template name="comment-escape-string.recursive">
<xsl:with-param name="string" select="$string"/>
</xsl:call-template>
<xsl:if test="substring($string, string-length($string), 1) = '-'">
<xsl:text> </xsl:text>
</xsl:if>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<refentry id="comment-escape-string.recursive">
<refnamediv>
<refname>comment-escape-string.recursive</refname>
<refpurpose>Internal function used by comment-escape-string</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>The <function>comment-escape-string.recursive</function> template is used
by <function>comment-escape-string</function>.</para>
<programlisting><src:fragment id="comment-escape-string.recursive">
<xsl:template name="comment-escape-string.recursive">
<xsl:param name="string" select="''"/>
<xsl:choose>
<xsl:when test="contains($string, '--')">
<xsl:value-of select="substring-before($string, '--')"/>
<xsl:value-of select="'- -'"/>
<xsl:call-template name="comment-escape-string.recursive">
<xsl:with-param name="string" select="substring-after($string, '--')"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$string"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
</reference>
<reference>
<title>Relative URI Functions</title>
<partintro><title>Introduction</title>
<para>These functions manipulate relative URI references.</para>
<para>The following assumptions must hold true:</para>
<orderedlist>
<listitem>
<para>All URIs are relative.</para>
</listitem>
<listitem>
<para>No URI contains the <quote><literal>../</literal></quote> sequence
which would effectively move <quote>up</quote> the hierarchy.</para>
</listitem>
</orderedlist>
<para>If these assumptions do not hold, the results are unpredictable.</para>
</partintro>
<refentry id="count.uri.path.depth">
<refnamediv>
<refname>count.uri.path.depth</refname>
<refpurpose>Count the number of path components in a relative URI</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>This function counts the number of path components in a relative URI.</para>
<programlisting><src:fragment id='count.uri.path.depth.frag'>
<xsl:template name="count.uri.path.depth">
<xsl:param name="filename" select="''"/>
<xsl:param name="count" select="0"/>
<xsl:choose>
<xsl:when test="contains($filename, '/')">
<xsl:call-template name="count.uri.path.depth">
<xsl:with-param name="filename" select="substring-after($filename, '/')"/>
<xsl:with-param name="count" select="$count + 1"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$count"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
<refentry id="trim.common.uri.paths">
<refnamediv>
<refname>trim.common.uri.paths</refname>
<refpurpose>Trim common leading path components from a relative URI</refpurpose>
</refnamediv>
<refsect1><title>Description</title>
<para>This function trims common leading path components from a relative URI.</para>
<programlisting><src:fragment id='trim.common.uri.paths.frag'>
<xsl:template name="trim.common.uri.paths">
<xsl:param name="uriA" select="''"/>
<xsl:param name="uriB" select="''"/>
<xsl:param name="return" select="'A'"/>
<xsl:choose>
<xsl:when test="contains($uriA, '/') and contains($uriB, '/')
and substring-before($uriA, '/') = substring-before($uriB, '/')">
<xsl:call-template name="trim.common.uri.paths">
<xsl:with-param name="uriA" select="substring-after($uriA, '/')"/>
<xsl:with-param name="uriB" select="substring-after($uriB, '/')"/>
<xsl:with-param name="return" select="$return"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:choose>
<xsl:when test="$return = 'A'">
<xsl:value-of select="$uriA"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$uriB"/>
</xsl:otherwise>
</xsl:choose>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</src:fragment></programlisting>
</refsect1>
</refentry>
</reference>
<appendix><title>The Stylesheet</title>
<para>The <filename>lib.xsl</filename> stylesheet is just a wrapper
around these functions.</para>
<src:fragment id="top" mundane-result-prefixes="xsl">
<!-- ********************************************************************
$Id$
********************************************************************
This file is part of the XSL DocBook Stylesheet distribution.
See ../README or http://nwalsh.com/docbook/xsl/ for copyright
and other information.
This module implements DTD-independent functions
******************************************************************** -->
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
exclude-result-prefixes="src"
version='1.0'>
<src:fragref linkend="dot.count.frag"/>
<src:fragref linkend="copy-string.frag"/>
<src:fragref linkend="string.subst.frag"/>
<src:fragref linkend="xpointer.idref.frag"/>
<src:fragref linkend="length-magnitude.frag"/>
<src:fragref linkend="length-units.frag"/>
<src:fragref linkend="length-spec.frag"/>
<src:fragref linkend="length-in-points.frag"/>
<src:fragref linkend="pi-attribute.frag"/>
<src:fragref linkend="lookup.key.frag"/>
<src:fragref linkend="xpath.location.frag"/>
<src:fragref linkend="comment-escape-string"/>
<src:fragref linkend="comment-escape-string.recursive"/>
<src:fragref linkend="count.uri.path.depth.frag"/>
<src:fragref linkend="trim.common.uri.paths.frag"/>
</xsl:stylesheet>
</src:fragment>
</appendix>
</book>