<?xml version="1.0"?>
<reference xml:id="utility">
<info>
<title>Common » Utility Template Reference</title>
<releaseinfo role="meta">
$Id: utility.xsl 7101 2007-07-20 15:32:12Z xmldoc $
</releaseinfo>
</info>
<partintro xml:id="partintro">
<title>Introduction</title>
<para>This is technical reference documentation for the
miscellaneous utility templates in the DocBook XSL
Stylesheets.</para>
<note>
<para>These templates are defined in a separate file from the set
of “common” templates because some of the common templates
reference DocBook XSL stylesheet parameters, requiring the
entire set of parameters to be imported/included in any
stylesheet that imports/includes the common templates.</para>
<para>The utility templates don’t import or include any DocBook
XSL stylesheet parameters, so the utility templates can be used
without importing the whole set of parameters.</para>
</note>
<para>This is not intended to be user documentation. It is
provided for developers writing customization layers for the
stylesheets.</para>
</partintro>
<refentry xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="template.log.message">
<refnamediv>
<refname>log.message</refname>
<refpurpose>Logs/emits formatted notes and warnings</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis><xsl:template name="log.message">
<xsl:param name="level"/>
<xsl:param name="source"/>
<xsl:param name="context-desc"/>
<xsl:param name="context-desc-field-length">12</xsl:param>
<xsl:param name="context-desc-padded">
<xsl:if test="not($context-desc = '')">
<xsl:call-template name="pad-string">
<xsl:with-param name="leftRight">right</xsl:with-param>
<xsl:with-param name="padVar" select="substring($context-desc, 1, $context-desc-field-length)"/>
<xsl:with-param name="length" select="$context-desc-field-length"/>
</xsl:call-template>
</xsl:if>
</xsl:param>
<xsl:param name="message"/>
<xsl:param name="message-field-length" select="45"/>
<xsl:param name="message-padded">
<xsl:variable name="spaces-for-blank-level">
<!-- * if the level field is blank, we'll need to pad out -->
<!-- * the message field with spaces to compensate -->
<xsl:choose>
<xsl:when test="$level = ''">
<xsl:value-of select="4 + 2"/>
<!-- * 4 = hard-coded length of comment text ("Note" or "Warn") -->
<!-- * + 2 = length of colon-plus-space separator ": " -->
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="0"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="spaces-for-blank-context-desc">
<!-- * if the context-description field is blank, we'll need -->
<!-- * to pad out the message field with spaces to compensate -->
<xsl:choose>
<xsl:when test="$context-desc = ''">
<xsl:value-of select="$context-desc-field-length + 2"/>
<!-- * + 2 = length of colon-plus-space separator ": " -->
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="0"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="extra-spaces" select="$spaces-for-blank-level + $spaces-for-blank-context-desc"/>
<xsl:call-template name="pad-string">
<xsl:with-param name="leftRight">right</xsl:with-param>
<xsl:with-param name="padVar" select="substring($message, 1, ($message-field-length + $extra-spaces))"/>
<xsl:with-param name="length" select="$message-field-length + $extra-spaces"/>
</xsl:call-template>
</xsl:param>
...
</xsl:template></synopsis>
</refsynopsisdiv>
<refsect1><title>Description</title>
<para>The <function>log.message</function> template is a utility
template for logging/emitting formatted messages – that is,
notes and warnings, along with a given log “level” and an
identifier for the “source” that the message relates to.</para>
</refsect1><refsect1><title>Parameters</title>
<variablelist>
<varlistentry><term>level</term>
<listitem>
<para>Text to log/emit in the message-level field to
indicate the message level
(<literal>Note</literal> or
<literal>Warning</literal>)</para>
</listitem>
</varlistentry>
<varlistentry><term>source</term>
<listitem>
<para>Text to log/emit in the source field to identify the
“source” to which the notification/warning relates.
This can be any arbitrary string, but because the
message lacks line and column numbers to identify the
exact part of the source document to which it
relates, the intention is that the value you pass
into the <literal>source</literal> parameter should
give the user some way to identify the portion of
their source document on which to take potentially
take action in response to the log message (for
example, to edit, change, or add content).</para>
<para>So the <literal>source</literal> value should be,
for example, an ID, book/chapter/article title, title
of some formal object, or even a string giving an
XPath expression.</para>
</listitem>
</varlistentry>
<varlistentry><term>context-desc</term>
<listitem>
<para>Text to log/emit in the context-description field to
describe the context for the message.</para>
</listitem>
</varlistentry>
<varlistentry><term>context-desc-field-length</term>
<listitem>
<para>Specifies length of the context-description field
(in characters); default is 12</para>
<para>If the text specified by the
<literal>context-desc</literal> parameter is longer
than the number of characters specified in
<literal>context-desc-field-length</literal>, it is
truncated to <literal>context-desc-field-length</literal>
(12 characters by default).</para>
<para>If the specified text is shorter than
<literal>context-desc-field-length</literal>,
it is right-padded out to
<literal>context-desc-field-length</literal> (12 by
default).</para>
<para>If no value has been specified for the
<literal>context-desc</literal> parameter, the field is
left empty and the text of the log message begins with
the value of the <literal>message</literal>
parameter.</para>
</listitem>
</varlistentry>
<varlistentry><term>message</term>
<listitem>
<para>Text to log/emit in the actual message field</para>
</listitem>
</varlistentry>
<varlistentry><term>message-field-length</term>
<listitem>
<para>Specifies length of the message
field (in characters); default is 45</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1><refsect1><title>Returns</title>
<para>Outputs a message (generally, to standard error).</para>
</refsect1></refentry>
<refentry xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="template.get.doc.title">
<refnamediv>
<refname>get.doc.title</refname>
<refpurpose>Gets a title from the current document</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis><xsl:template name="get.doc.title"/></synopsis>
</refsynopsisdiv>
<refsect1><title>Description</title>
<para>The <function>get.doc.title</function> template is a
utility template for returning the first title found in the
current document.</para>
</refsect1><refsect1><title>Returns</title>
<para>Returns a string containing some identifying title for the
current document .</para>
</refsect1></refentry>
<refentry xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="template.pad-string">
<refnamediv>
<refname>pad-string</refname>
<refpurpose>Right-pads or left-pads a string out to a certain length</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis><xsl:template name="pad-string">
<xsl:param name="padChar" select="' '"/>
<xsl:param name="leftRight">left</xsl:param>
<xsl:param name="padVar"/>
<xsl:param name="length"/>
...
</xsl:template></synopsis>
</refsynopsisdiv>
<refsect1><title>Description</title>
<para>This function takes string <parameter>padVar</parameter> and
pads it out in the direction <parameter>rightLeft</parameter> to
the string-length <parameter>length</parameter>, using string
<parameter>padChar</parameter> (a space character by default) as
the padding string (note that <parameter>padChar</parameter> can
be a string; it is not limited to just being a single
character).</para>
<note>
<para>This function began as a copy of Nate Austin's
<function>prepend-pad</function> function in the <link xlink:href="http://www.dpawson.co.uk/xsl/sect2/padding.html">Padding
Content</link> section of Dave Pawson's <link xlink:href="http://www.dpawson.co.uk/xsl/index.html">XSLT
FAQ</link>.</para>
</note>
</refsect1><refsect1><title>Returns</title>
<para>Returns a (padded) string.</para>
</refsect1></refentry>
</reference>