lib.xweb

数据仓库工具

    <xsl:when test="$units = 'pc'">
      <xsl:value-of select="$magnitude div 6.0 * 72.0"/>
    </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('')"/>
  <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:choose>
        <xsl:when test="contains($pi,concat(' ', $attribute, '='))">
          <xsl:variable name="rest" select="substring-after($pi,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: lib.xweb,v 1.1 2003/08/12 14:12:54 zoran Exp $
     ********************************************************************

     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>