File: xfpt.html

package info (click to toggle)
xfpt 1.00-3
links: PTS, VCS
area: main
in suites: forky, sid, trixie
size: 856 kB
sloc: ansic: 1,775; sh: 176; perl: 140; makefile: 69
file content (1459 lines) | stat: -rw-r--r-- 85,300 bytes
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><style xmlns="" type="text/css">
div.added    { background-color: #ffff99; }
div.deleted  { text-decoration: line-through;
               background-color: #FF7F7F; }
div.changed  { background-color: #99ff99; }
div.off      {  }

span.added   { background-color: #ffff99; }
span.deleted { text-decoration: line-through;
               background-color: #FF7F7F; }
span.changed { background-color: #99ff99; }
span.off     {  }



pre.literallayout {
  background-color: #E8E8D0;
  padding-left: 0.5cm;
  padding-top:  5px;
  padding-bottom: 5px;
}

div[class=changed] pre.literallayout {
  background-color: #99ff99;
  padding-left: 0.5cm;
  padding-top:  5px;
  padding-bottom: 5px;
}

div.literallayout {
  background-color: #E8E8D0;
  padding-left: 0.5cm;
  padding-top:  5px;
  padding-bottom: 5px;
}

div[class=changed] div.literallayout {
  background-color: #99ff99;
  padding-left: 0.5cm;
  padding-top:  5px;
  padding-bottom: 5px;
}

</style>
<title>
The xfpt plain text to XML processor</title>
<meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" />
</head>
<body>
<div class="book">
<div class="titlepage">
<div>
<div>
<h1 class="title">
<a id="idm1">
</a>
The xfpt plain text to XML processor</h1>
</div>
<div>
<div class="author">
<h3 class="author">
<span class="firstname">
Philip</span>
<span class="surname">
Hazel</span>
</h3>
</div>
</div>
<div>
<p class="copyright">
Copyright © 2023 University of Cambridge</p>
</div>
<div>
<div class="revhistory">
<table style="border-style:solid; width:100%;" summary="Revision History">
<tr>
<th align="left" valign="top" colspan="3">
<strong>
Revision History</strong>
</th>
</tr>
<tr>
<td align="left">
Revision 1.00</td>
<td align="left">
08 March 2023</td>
<td align="left">
PH</td>
</tr>
</table>
</div>
</div>
</div>
<hr />
</div>
<div class="toc">
<p>
<strong>
Table of Contents</strong>
</p>
<dl class="toc">
<dt>
<span xmlns="" class="chapter">
<a id="toc0001" href="#ID00">
1. Introduction</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span xmlns="" class="section">
<a id="toc0002" href="#ID01">
1.1. The <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis">
<em>
xfpt</em>
</span>
command line</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0003" href="#ID02">
1.2. A short <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis">
<em>
xfpt</em>
</span>
example</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0004" href="#SECTliteralprocessing">
1.3. Literal and non-literal processing</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0005" href="#ID04">
1.4. Format of directive lines</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0006" href="#SECTcallingmacro">
1.5. Calling macros</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span xmlns="" class="chapter">
<a id="toc0007" href="#ID06">
2. Flag sequences</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span xmlns="" class="section">
<a id="toc0008" href="#ID07">
2.1. Flag sequences for XML entities and <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis">
<em>
xfpt</em>
</span>
variables</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0009" href="#ID08">
2.2. Flag sequences for calling macros</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0010" href="#ID09">
2.3. Other flag sequences</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0011" href="#ID10">
2.4. Unrecognized flag sequences</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0012" href="#ID11">
2.5. Standard flag sequences</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span xmlns="" class="chapter">
<a id="toc0013" href="#ID12">
3. Built-in directive processing</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span xmlns="" class="section">
<a id="toc0014" href="#ID13">
3.1. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.arg</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0015" href="#ID14">
3.2. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.eacharg</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0016" href="#ID15">
3.3. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.echo</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0017" href="#ID16">
3.4. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.endarg</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0018" href="#ID17">
3.5. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.endeach</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0019" href="#ID18">
3.6. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.endinliteral</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0020" href="#ID19">
3.7. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.flag</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0021" href="#ID20">
3.8. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.include</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0022" href="#ID21">
3.9. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.inliteral</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0023" href="#ID22">
3.10. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.literal</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0024" href="#SECTmacro">
3.11. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.macro</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0025" href="#ID24">
3.12. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.nest</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0026" href="#ID25">
3.13. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.nonl</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0027" href="#ID26">
3.14. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.pop</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0028" href="#ID27">
3.15. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.push</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0029" href="#SECTrevision">
3.16. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.revision</strong>
</span>
directive</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0030" href="#ID29">
3.17. The <span xmlns="http://www.w3.org/1999/xhtml" class="bold">
<strong>
.set</strong>
</span>
directive</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span xmlns="" class="chapter">
<a id="toc0031" href="#CHAPstdmac">
4. The standard macros for DocBook</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span xmlns="" class="section">
<a id="toc0032" href="#ID31">
4.1. Overall setup</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0033" href="#idm480">
4.2. Processing instructions</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0034" href="#ID32">
4.3. Chapters, sections, and subsections</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0035" href="#ID33">
4.4. Prefaces, appendixes, and colophons</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0036" href="#idm518">
4.5. Terminating chapters, etc.</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0037" href="#ID34">
4.6. URL references</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0038" href="#ID35">
4.7. Itemized lists</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0039" href="#ID36">
4.8. Ordered lists</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0040" href="#ID37">
4.9. Variable lists</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0041" href="#ID38">
4.10. Nested lists</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0042" href="#ID39">
4.11. Displayed text</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0043" href="#ID40">
4.12. Block quotes</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0044" href="#SECTrevmacs">
4.13. Revision markings</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0045" href="#ID42">
4.14. Informal tables</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0046" href="#ID43">
4.15. Formal tables</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0047" href="#ID44">
4.16. Figures and images</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0048" href="#ID45">
4.17. Footnotes</a>
</span>
</dt>
<dt>
<span xmlns="" class="section">
<a id="toc0049" href="#ID46">
4.18. Indexes</a>
</span>
</dt>
</dl>
</dd>
</dl>
</div>
<div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a href="#" id="ID00">1. Introduction</a></h1></div></div></div><p><span class="emphasis"><em>xfpt</em></span> is a program that converts a marked up source document coded in UTF-8 into
an XML document. It was written with DocBook XML in mind, but can also be used
to create other forms of XML. Unlike some other processors, <span class="emphasis"><em>xfpt</em></span> does not try to
produce XML from input that is also usable as a freestanding document. This
makes it less ambiguous for large and/or complicated documents. <span class="emphasis"><em>xfpt</em></span> is aimed at
users who understand the XML that they are generating. It makes it easy to
include literal XML, either in blocks, or within paragraphs. <span class="emphasis"><em>xfpt</em></span> restricts
itself to two special characters that trigger all its processing.
</p><p>
<span class="emphasis"><em>xfpt</em></span> treats any input line that starts with a dot as a <span class="emphasis"><em>directive</em></span> line.
Directives control the way the input is processed. A small number of directives
are implemented in the program itself. A macro facility makes it possible to
combine these in various ways to define directives for higher-level concepts
such as chapters and sections. A standard macro library that generates a simple
subset of DocBook XML is provided. The only XML element that the program itself
generates is <code class="literal">&lt;para&gt;</code>; all the others must be included as literal XML, either
directly in the input text, or, more commonly, as part of the text that is
generated by a macro call.
</p><p>
The ampersand character is special within non-literal text that is processed by
<span class="emphasis"><em>xfpt</em></span>. An ampersand introduces a <span class="emphasis"><em>flag sequence</em></span> that modifies the output.
Ampersand was chosen because it is also special in XML. As well as recognizing
flag sequences that begin with an ampersand, <span class="emphasis"><em>xfpt</em></span> converts grave accents and
apostrophes that appear in non-literal text into typographic opening and
closing quotes, as follows:
</p><div class="literallayout">
 <code class="literal"> `    </code>  becomes  ‘<br />
 <code class="literal"> '    </code>  becomes  ’<br />
</div><p>
Within normal input text, ampersand, grave accent, and apostrophe are the only
characters that cause <span class="emphasis"><em>xfpt</em></span> to change the input text, but this applies only to
non-literal text. In literal text, there are no markup characters, and only a
dot at the start of a line is recognized as special. Within the body of a
macro, there is one more special character: the dollar character is used to
introduce an argument substitution.
</p><p>
Notwithstanding the previous paragraph, <span class="emphasis"><em>xfpt</em></span> knows that it is generating XML,
and in all cases when a literal ampersand or angle bracket is required in the
output, the appropriate XML entity reference (<code class="literal">&amp;amp;</code>, <code class="literal">&amp;lt;</code>, or
<code class="literal">&amp;gt;</code>, respectively) is generated.
</p><p>
Binary zero characters in the input are not supported. If one is encountered, 
an error message is generated and the character is ignored.
</p><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID01">1.1 The <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis"><em>xfpt</em></span> command line</a></h3></div></div></div><p>The format of the <span class="emphasis"><em>xfpt</em></span> command line is:
</p><div class="literallayout">
 <code class="literal">xfpt [</code><span class="emphasis"><em>options</em></span><code class="literal">] [</code><span class="emphasis"><em>input source</em></span><code class="literal">]</code><br />
</div><p>
If no input is specified, the standard input is read. There are four options:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><span class="option"><strong>-help</strong></span> or <span class="option"><strong>--help</strong></span></span></dt><dd><p>
This option causes <span class="emphasis"><em>xfpt</em></span> to output its <span class="quote">“<span class="quote">usage</span>”</span> message, and exit.  
</p></dd><dt><span class="term"><span class="option"><strong>-o</strong></span> <span class="emphasis"><em>&lt;output destination&gt;</em></span></span></dt><dd><p>
This option overrides the default destination. If the standard input is being
read, the default destination is the standard output. Otherwise, the default
destination is the name of the input file with the extension <em class="filename">.xml</em>,
replacing its existing extension if there is one. A single hyphen character can
be given as an output destination to refer to the standard output.
</p></dd><dt><span class="term"><span class="option"><strong>-S</strong></span> <span class="emphasis"><em>&lt;directory path&gt;</em></span></span></dt><dd><p>
This option overrides the path to <span class="emphasis"><em>xfpt</em></span>’s library directory that is built into
the program. This makes it possible to use or test alternate libraries.
</p></dd><dt><span class="term"><span class="option"><strong>-v</strong></span> or <span class="option"><strong>--version</strong></span></span></dt><dd><p>
This option causes <span class="emphasis"><em>xfpt</em></span> to output its version number and exit.
</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID02">1.2 A short <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis"><em>xfpt</em></span> example</a></h3></div></div></div><p>Here is a very short example of a complete <span class="emphasis"><em>xfpt</em></span> input file that uses some of the
standard macros and flags:
</p><pre class="literallayout">
 .include stdflags
 .include stdmacs
 .docbook
 .book

 .chapter "The first chapter"
 This is the text of the first chapter. Here is an &amp;'italic'&amp;
 word, and here is a &amp;*bold*&amp; one.

 .section "This is a section heading"
 We can use the &amp;*ilist*&amp; macro to generate an itemized list:
 .ilist
 The first item in the list.
 .next
 The last item in the list.
 .endlist

 There are also standard macros for ordered lists, literal
 layout blocks, code blocks, URL references, index entries,
 tables, footnotes, figures, etc.
</pre></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="SECTliteralprocessing">1.3 Literal and non-literal processing</a></h3></div></div></div><p><span class="emphasis"><em>xfpt</em></span> processes non-directive input lines in one of four ways (known as
<span class="quote">“<span class="quote">modes</span>”</span>):
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
In the default mode, text is processed paragraph by paragraph. 
<a href="#ftn.idm101" class="footnote" id="idm101"><sup class="footnote">[1]</sup></a>
The end of a paragraph is indicated by the end of the input, a blank line, or
by an occurrence of the <span class="bold"><strong>.literal</strong></span> directive. Other directives (for example,
<span class="bold"><strong>.include</strong></span>) do not of themselves terminate a paragraph. Most of the standard
macros (such as <span class="bold"><strong>.chapter</strong></span> and <span class="bold"><strong>.section</strong></span>) force a paragraph end by
starting their contents with a <span class="bold"><strong>.literal</strong></span> directive. Because <span class="emphasis"><em>xfpt</em></span> reads a
whole paragraph before processing it, error messages contain the phrase
<span class="quote">“<span class="quote">detected near line <span class="emphasis"><em>nnn</em></span></span>”</span>, where the line number is typically that of the
last line of the paragraph.
</p></li><li class="listitem"><p>
In the <span class="quote">“<span class="quote">literal layout</span>”</span> mode, text is processed line by line, but is
otherwise handled as in the default mode. The only real difference this makes
to the markup from the user’s point of view is that both parts of a set of
paired flags must be on the same line. In this mode, error messages are more
likely to contain the exact line number where the fault lies. Literal layout
mode is used by the standard <span class="bold"><strong>.display</strong></span> macro to generate <code class="literal">&lt;literallayout&gt;</code>
elements.
</p></li><li class="listitem"><p>
In the <span class="quote">“<span class="quote">literal text</span>”</span> mode, text is also processed line by line, but no flags
are recognized. The only modification <span class="emphasis"><em>xfpt</em></span> makes to the text is to turn
ampersand and angle bracket characters into XML entity references. This mode is
used by the standard <span class="bold"><strong>.code</strong></span> macro to generate <code class="literal">&lt;literallayout&gt;</code> elements
that include <code class="literal">class=monospaced</code>.
</p></li><li class="listitem"><p>
In the <span class="quote">“<span class="quote">literal XML</span>”</span> mode, text lines are copied to the output without
modification. This is the easiest way to include a chunk of literal XML in the
output. An example might be the <code class="literal">&lt;bookinfo&gt;</code> element, which occurs only once
in a document. It is not worth setting up a macro for a one-off item like this.
</p></li></ul></div><p>
The <span class="bold"><strong>.literal</strong></span> directive switches between the modes. It is not normally used
directly, but instead is incorported into appropriate macro definitions. The 
<span class="bold"><strong>.inliteral</strong></span> directive can be used to test the current mode.
</p><p>
Directive lines are recognized and acted upon in all four modes. However, an
unrecognized line that starts with a dot in the literal text or literal XML
mode is treated as data. In the other modes, such a line provokes an error.
</p><p>
If you need to have a data line that begins with a dot in literal layout mode,
you can either specify it by character number, or precede it with some
non-acting markup. These two examples are both valid:
</p><pre class="literallayout">
 &amp;#x2e;start with a dot
 &amp;''&amp;.start with a dot
</pre><p>
The second example assumes the standard flags are defined: it precedes the dot 
with an empty italic string. However, this is untidy because the empty string
will be carried over into the XML.
</p><p>
In literal text or literal XML mode, it is not possible to have a data line
that starts with a dot followed by the name of a directive or macro. You have
to use literal layout mode if you require such output. Another solution, which
is used in the source for this document (where many examples show directive
lines), is to indent every displayed line by one space, and thereby avoid the
problem altogether.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID04">1.4 Format of directive lines</a></h3></div></div></div><p>If an input line starts with a dot followed by a space, it is ignored by <span class="emphasis"><em>xfpt</em></span>.
This provides a facility for including comments in the input. Otherwise, the
dot must be followed by a directive or macro name, and possibly one or more
arguments. Arguments that are strings are delimited by white space unless they
are enclosed in single or double quotes. The delimiting quote character can be
included within a quoted string by doubling it. Here are some examples:
</p><pre class="literallayout">
 .literal layout
 .set version 0.00
 .row "Jack's house" 'Jill''s house'
</pre><p>
An unrecognized directive line normally causes an error; however, in the
literal text and literal XML modes, an unrecognized line that starts with a
dot is treated as a data line.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="SECTcallingmacro">1.5 Calling macros</a></h3></div></div></div><p>Macros are defined by the <span class="bold"><strong>.macro</strong></span> directive, which is described in section
<a class="xref" href="#SECTmacro" title="3.11 The .macro directive">3.11</a>. There are two ways of calling a macro. It can be called in the
same way as a directive, or it can be called from within text that is being
processed. The second case is called an <span class="quote">“<span class="quote">inline macro call</span>”</span>.
</p><p>
When a macro is called as a directive, its name is given after a dot at the
start of a line, and the name may be followed by any number of optional
arguments, in the same way as a built-in directive.
For example:
</p><pre class="literallayout">
 .chapter "Chapter title" chapter-reference
</pre><p>
The contents of the macro, after argument substitution, are processed in
exactly the same way as normal input lines. A macro that is called as a 
directive may contain nested macro calls.
</p><p>
When a macro is called from within a text string, its name is given after an
ampersand, and is followed by an opening parenthesis. Arguments, delimited by
commas, can then follow, up to a closing parenthesis. If an argument contains a
comma or a closing parenthesis, it must be quoted. White space after a
separating comma is ignored. The most common example of this type of macro
call is the standard macro for generating a URL reference:
</p><pre class="literallayout">
 Refer to a URL via &amp;url(http://x.example,this text).
</pre><p>
There are differences in the behaviour of macros, depending on which way they
are called. A macro that is called inline may not contain references to other
macros; it must contain only text lines and calls to built-in directives.
Also, newlines that terminate text lines within the macro are not included in
the output. On the other hand, a macro that is called as a directive may 
contain lines that are themselves macro calls. There is a limit of 20 to the
depth of nesting of input sources (macro calls and included files). Nested 
macro calls may be recursive, though of course there must be a way of ending
the recursion.
</p><p>
A macro that can be called inline can always also be called as a directive, but
the opposite is not true. Macros are usually designed to be called either one
way or the other. However, the <span class="bold"><strong>.new</strong></span> and <span class="bold"><strong>.index</strong></span> macros in the standard
library are examples of macros that are designed be called either way.
</p></div><div class="footnotes"><br /><hr style="width:100; text-align:left;margin-left: 0" /><div id="ftn.idm101" class="footnote"><p><a href="#idm101" class="para"><sup class="para">[1] </sup></a>
There is, however, a special case when a paragraph contains one or more 
footnotes. In that situation, each part of the outer paragraph is processed 
independently.
</p></div></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a href="#" id="ID06">2. Flag sequences</a></h1></div></div></div><p>Only one flag sequence is built-into the code itself. If an input line ends
with three ampersands (ignoring trailing white space), the ampersands are
removed, and the next input line, with any leading white space removed, is
joined to the original line. This happens before any other processing, and may
involve any number of lines. Thus:
</p><div class="literallayout">
 <code class="literal">The quick &amp;&amp;&amp;</code><br />
 <code class="literal">    brown &amp;&amp;&amp;</code><br />
 <code class="literal">      fox.</code><br />
</div><p>
produces exactly the same output as:
</p><pre class="literallayout">
 The quick brown fox.
</pre><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID07">2.1 Flag sequences for XML entities and <span xmlns="http://www.w3.org/1999/xhtml" class="emphasis"><em>xfpt</em></span> variables</a></h3></div></div></div><p>If an ampersand is followed by a # character, a number, and a semicolon, it is
understood as a numerical reference to an XML entity, and is passed through
unmodified. The number can be decimal, or hexadecimal preceded by <code class="literal">x</code>. For
example:
</p><pre class="literallayout">
 This is an Ohm sign: &amp;#x2126;.
 This is a degree sign: &amp;#176;.
</pre><p>
If an ampersand is followed by a letter, a sequence of letters, digits, and
dots is read. If this is terminated by a semicolon, the characters between the
ampersand and the semicolon are interpreted as an entity name. This can be:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
The name of an inbuilt <span class="emphasis"><em>xfpt</em></span> variable. At present, there is only one of these,
called <code class="literal">xfpt.rev</code>. Its use is described with the <span class="bold"><strong>.revision</strong></span> directive
below.
</p></li><li class="listitem"><p>
The name of a user variable that has been set by the <span class="bold"><strong>.set</strong></span> directive, also
described below.
</p></li><li class="listitem"><p>
The name of an XML entity. This is assumed if the name is not recognized as one
of the previous types. In this case, the input text is passed to the output
without modification. For example:
</p><pre class="literallayout">
 This is an Ohm sign: &amp;Ohm;.
</pre></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID08">2.2 Flag sequences for calling macros</a></h3></div></div></div><p>If an ampersand is followed by a sequence of alphanumeric characters starting
with a letter, terminated by an opening parenthesis, the characters between the
ampersand and the parenthesis are interpreted as the name of a macro. See
section <a class="xref" href="#SECTcallingmacro" title="1.5 Calling macros">1.5</a> for more details.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID09">2.3 Other flag sequences</a></h3></div></div></div><p>Any other flag sequences that are needed must be defined by means of the
<span class="bold"><strong>.flag</strong></span> directive. These are of two types, standalone and paired. Both cases
define replacement text. This is always literal; it is not itself scanned for
flag occurrences.
</p><p>
Lines are scanned from left to right when flags are being interpreted. If
there is any ambiguity when a text string is being scanned, the longest flag
sequence wins. Thus, it is possible (as in the standard flag sequences) to
define both <code class="literal">&amp;&lt;</code> and <code class="literal">&amp;&lt;&lt;</code> as flags, provided that you never want to
follow the first of them with a <code class="literal">&lt;</code> character.
</p><p>
You can define flags that start with <code class="literal">&amp;#</code>, but these must be used with care,
lest they be misinterpreted as numerical references to XML entities.
</p><p>
A standalone flag consists of an ampersand followed by any number of
non-alphanumeric characters. When it is encountered, it is replaced by its
replacement text. For example, in the standard flag definitions, <code class="literal">&amp;&amp;</code>
is defined as a standalone flag with with the replacement text <code class="literal">&amp;amp;</code>.
</p><p>
A paired flag is defined as two sequences. The first takes the same form as a
standalone flag. The second also consists of non-alphanumeric characters, but
need not start with an ampersand. It is often defined as the reverse of the
first sequence. For example, in the standard definitions, <code class="literal">&amp;'</code> and
<code class="literal">'&amp;</code> are defined as a flag pair for enclosing text in an <code class="literal">&lt;emphasis&gt;</code>
element.
</p><p>
When the first sequence of a paired flag is encountered, its partner is
expected to be found within the same text unit. In the default mode, the units
are a paragraphs, or part-paragraphs if footnotes intervene. In literal layout
mode, the text is processed line by line. Each member of the pair is replaced
by its replacement text. 
</p><p>
Multiple occurrences of paired flags must be correctly nested. Note that,
though <span class="emphasis"><em>xfpt</em></span> diagnoses an error for badly nested flag pairs, it does not prevent
you from generating invalid XML. For example, DocBook does not allow
<code class="literal">&lt;emphasis&gt;</code> within <code class="literal">&lt;literal&gt;</code>, though it does allow <code class="literal">&lt;literal&gt;</code> within
<code class="literal">&lt;emphasis&gt;</code>.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID10">2.4 Unrecognized flag sequences</a></h3></div></div></div><p>If an ampersand is not followed by a character sequence in one of the forms
described in the preceding sections, an error occurs.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID11">2.5 Standard flag sequences</a></h3></div></div></div><p>These are the standalone flag sequences that are defined in the <em class="filename">stdflags</em>
file in the <span class="emphasis"><em>xfpt</em></span> library:
</p><div class="literallayout">
 <code class="literal">&amp;&amp;        </code> becomes <code class="literal"> &amp;amp;</code> (ampersand)<br />
 <code class="literal">&amp;--       </code> becomes <code class="literal"> &amp;ndash;</code> (en-dash)<br />
 <code class="literal">&amp;~        </code> becomes <code class="literal"> &amp;nbsp;</code> (‘hard’ space)<br />
</div><p>
These are the flag pairs that are defined in the <em class="filename">stdflags</em> file in the <span class="emphasis"><em>xfpt</em></span>
library:
</p><div class="literallayout">
 <code class="literal">&amp;"..."&amp;   </code> becomes <code class="literal">&lt;quote&gt;...&lt;/quote&gt;</code><br />
 <code class="literal">&amp;'...'&amp;   </code> becomes <code class="literal">&lt;emphasis&gt;...&lt;/emphasis&gt;</code><br />
 <code class="literal">&amp;*...*&amp;   </code> becomes <code class="literal">&lt;emphasis role="bold"&gt;...&lt;/emphasis&gt;</code><br />
 <code class="literal">&amp;`...`&amp;   </code> becomes <code class="literal">&lt;literal&gt;...&lt;/literal&gt;</code><br />
 <code class="literal">&amp;_..._&amp;   </code> becomes <code class="literal">&lt;filename&gt;...&lt;/filename&gt;</code><br />
 <code class="literal">&amp;(...)&amp;   </code> becomes <code class="literal">&lt;command&gt;...&lt;/command&gt;</code><br />
 <code class="literal">&amp;[...]&amp;   </code> becomes <code class="literal">&lt;function&gt;...&lt;/function&gt;</code><br />
 <code class="literal">&amp;%...%&amp;   </code> becomes <code class="literal">&lt;option&gt;...&lt;/option&gt;</code><br />
 <code class="literal">&amp;$...$&amp;   </code> becomes <code class="literal">&lt;varname&gt;...&lt;/varname&gt;</code><br />
 <code class="literal">&amp;&lt;...&gt;&amp;   </code> becomes <code class="literal">&lt;...&gt;</code><br />
 <code class="literal">&amp;&lt;&lt;...&gt;&gt;&amp; </code> becomes <code class="literal">&lt;xref linkend="..."/&gt;</code><br />
</div><p>
For example, if you want to include a literal XML element in your output, you
can do it like this: <code class="literal">&amp;&lt;element&gt;&amp;</code>. If you want to include a longer
sequence of literal XML, changing to the literal XML mode may be more
convenient.
</p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a href="#" id="ID12">3. Built-in directive processing</a></h1></div></div></div><p>The directives that are built into the code of <span class="emphasis"><em>xfpt</em></span> are now described in
alphabetical order. You can see more examples of their use in the descriptions
of the standard macros in chapter <a class="xref" href="#CHAPstdmac" title="4. The standard macros for DocBook">4</a>.
</p><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID13">3.1 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.arg</strong></span> directive</a></h3></div></div></div><p>This directive tests for the existence of a non-empty argument. It may appear
only within the body of a macro and must be followed by a single number,
optionally preceded by a minus sign. If the number is positive (no minus sign),
subsequent lines, up to a <span class="bold"><strong>.endarg</strong></span> directive, are skipped unless the macro
has been called with at least that number of arguments and the argument whose
number is given is not an empty string. If the number is negative (minus sign
present), the test is inverted. That is, subsequent lines are used only if the
macro has been called with fewer than that number of arguments, or with an
empty string for the given argument. For example:
</p><pre class="literallayout">
 .macro example
 .arg 2
 Use these lines if there are at least 2 arguments 
 and the second one is not empty. Normally there would 
 be a reference to the 2nd argument. 
 .endarg
 .arg -2 
 Use these lines unless there are at least 2 arguments 
 and the second one is not empty. 
 .endarg 
 .endmacro
</pre><p>
If a macro is defined with default values for its arguments, these are not
counted by the <span class="bold"><strong>.arg</strong></span> directive, which looks only at the actual arguments in
a particular macro call. The <span class="bold"><strong>.arg</strong></span> directive may be nested.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID14">3.2 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.eacharg</strong></span> directive</a></h3></div></div></div><p>This directive may appear only within the body of a macro. It may optionally be
followed by a single number; if omitted the value is taken to be 1. Subsequent
lines, up to a <span class="bold"><strong>.endeach</strong></span> directive, are processed multiple times, once for
each argument, starting with the argument whose number is given. If the macro
is called with fewer arguments, the lines up to <span class="bold"><strong>.endeach</strong></span> are skipped, and
are not processed at all. When these lines are being processed, the remaining
actual macro arguments can be referenced relative to the current argument.
<code class="literal">$+1</code> refers to the current argument, <code class="literal">$+2</code> to the next argument, and so
on. Unlike <span class="bold"><strong>.arg</strong></span>, an argument that is an empty string is not treated
specially. However, like <span class="bold"><strong>.arg</strong></span>, only the actual arguments of a macro call
are considered. Default argument values do not count, though if an unsupplied
argument is reference by an absolute number such as <code class="literal">$3</code> the default value
will be inserted if it exists.
</p><p>
The <span class="bold"><strong>.endeach</strong></span> directive may also be followed by a number, again defaulting
to 1. When <span class="bold"><strong>.endeach</strong></span> is reached, the current argument number is incremented
by that number. If there are still unused arguments available, the lines
between <span class="bold"><strong>.eacharg</strong></span> and <span class="bold"><strong>.endeach</strong></span> are processed again.
</p><p>
This example is taken from the coding for the standard <span class="bold"><strong>.row</strong></span> macro, which
generates an <code class="literal">&lt;entry&gt;</code> element for each of its arguments:
</p><pre class="literallayout">
 .eacharg
 &amp;&lt;entry&gt;&amp;$+1&amp;&lt;/entry&gt;&amp;
 .endeach
</pre><p>
This example is taken from the coding for the standard <span class="bold"><strong>.itable</strong></span> macro, which
processes arguments in pairs to define the table’s columns, starting from the
fifth argument:
</p><pre class="literallayout">
 .eacharg 5
 &amp;&lt;colspec colwidth="$+1" align="$+2"/&gt;&amp;
 .endeach 2
</pre><p>
The <span class="bold"><strong>.eacharg</strong></span> directive may in principle be nested, though this does not 
seem useful in practice.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID15">3.3 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.echo</strong></span> directive</a></h3></div></div></div><p>This directive takes a single string argument. It writes it to the standard
error stream. Within a macro, argument substitution takes place, but no other
processing is done on the string. This directive can be useful for debugging
macros or writing comments to the user.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID16">3.4 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.endarg</strong></span> directive</a></h3></div></div></div><p>See the description of <span class="bold"><strong>.arg</strong></span> above.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID17">3.5 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.endeach</strong></span> directive</a></h3></div></div></div><p>See the description of <span class="bold"><strong>.eacharg</strong></span> above.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID18">3.6 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.endinliteral</strong></span> directive</a></h3></div></div></div><p>See the description of <span class="bold"><strong>.inliteral</strong></span> below.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID19">3.7 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.flag</strong></span> directive</a></h3></div></div></div><p>This directive is used to define flag sequences. The directive must be followed
either by a standalone flag sequence and one string in quotes, or by a flag
pair and two strings in quotes. White space separates these items. For example:
</p><pre class="literallayout">
 .flag &amp;&amp; "&amp;amp;"
 .flag &amp;" "&amp;  "&lt;quote&gt;"  "&lt;/quote&gt;"
</pre><p>
There are more examples in the definitions of the standard flags. If you
redefine an existing flag, the new definition overrides the old. There is no
way to revert to the previous definition.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID20">3.8 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.include</strong></span> directive</a></h3></div></div></div><p>This directive must be followed by a single string argument that is the path to
a file. The contents of the file are read and incorporated into the input at
this point. If the string does not contain any slashes, the path to the <span class="emphasis"><em>xfpt</em></span>
library is prepended. Otherwise, the path is used unaltered. If 
<span class="bold"><strong>.include</strong></span> is used inside a macro, it is evaluated each time the macro is 
called, and thus can be used to include a different file on each occasion.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID21">3.9 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.inliteral</strong></span> directive</a></h3></div></div></div><p>This directive may appear only within the body of a macro. It must be followed 
by one of the words <span class="quote">“<span class="quote">layout</span>”</span>, <span class="quote">“<span class="quote">text</span>”</span>, <span class="quote">“<span class="quote">off</span>”</span>, or <span class="quote">“<span class="quote">xml</span>”</span>. If the current 
literal mode does not correspond to the word, subsequent lines, up to a 
<span class="bold"><strong>.endinliteral</strong></span> directive, are skipped. The <span class="bold"><strong>.inliteral</strong></span> directive may be
nested.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID22">3.10 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.literal</strong></span> directive</a></h3></div></div></div><p>This must be followed by one of the words <span class="quote">“<span class="quote">layout</span>”</span>, <span class="quote">“<span class="quote">text</span>”</span>, <span class="quote">“<span class="quote">off</span>”</span>, or
<span class="quote">“<span class="quote">xml</span>”</span>. It forces an end to a previous paragraph, if there is one, and then
switches between processing modes. The default mode is the <span class="quote">“<span class="quote">off</span>”</span> mode, in
which text is processed paragraph by paragraph, and flags are recognized.
Section <a class="xref" href="#SECTliteralprocessing" title="1.3 Literal and non-literal processing">1.3</a> describes how input lines are processed in
the four modes.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="SECTmacro">3.11 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.macro</strong></span> directive</a></h3></div></div></div><p>This directive is used to define macros. It must be followed by a macro name,
and then, optionally, by any number of arguments. The macro name can be any
sequence of non-whitespace characters. The arguments in the definition provide
default values. The following lines, up to <span class="bold"><strong>.endmacro</strong></span>, form the body of the
macro. They are not processed in any way when the macro is defined; they are
processed only when the macro is called (see section <a class="xref" href="#SECTcallingmacro" title="1.5 Calling macros">1.5</a>).
</p><p>
Within the body of a macro, argument substitutions can be specified by means of
a dollar character and an argument number, for example, <code class="literal">$3</code> for the third
argument. See also <span class="bold"><strong>.eacharg</strong></span> above for the use of <code class="literal">$+</code> to refer to
relative arguments when looping through them. A reference to an argument that
is not supplied, and is not given a default, results in an empty substitution.
There is also a facility for a conditional substitution. A reference to an
argument of the form:
</p><div class="literallayout">
<code class="literal">$=</code><span class="emphasis"><em>&lt;digits&gt;&lt;delimiter&gt;&lt;text&gt;&lt;delimiter&gt;</em></span><br />
</div><p>
inserts the text if the argument is defined and is not an empty string, and
nothing otherwise. The text is itself scanned for flags and argument
substitutions. The delimiter must be a single character that does not appear in
the text. For example:
</p><pre class="literallayout">
&amp;&lt;chapter$=2+ id="$2"+&gt;&amp;
</pre><p>
If this appears in a macro that is called with only one argument, the result
is:
</p><pre class="literallayout">
&lt;chapter&gt;
</pre><p>
but if the second argument is, say <code class="literal">abcd</code>, the result is:
</p><pre class="literallayout">
&lt;chapter id="abcd"&gt;
</pre><p>
This conditional feature can be used with both absolute and relative argument
references. If a dollar character is required as data within the body of a
macro, it must be doubled. For example:
</p><pre class="literallayout">
  .macro price
  The price is $$1.
  .endmacro
</pre><p>
If you redefine an existing macro, the new definition overrides the old. There
is no way to revert to the previous definition. If you define a macro whose 
name is the same as the name of a built-in directive you will not be able to 
call it, because <span class="emphasis"><em>xfpt</em></span> looks for built-in directives before it looks for macros.
</p><p>
It is possible to define a macro within a macro, though clearly care must be 
taken with argument references to ensure that substitutions happen at the right
level.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID24">3.12 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.nest</strong></span> directive</a></h3></div></div></div><p>This directive must be followed by one of the words <span class="quote">“<span class="quote">begin</span>”</span> or <span class="quote">“<span class="quote">end</span>”</span>. It is
used to delimit a nested sequence of independent text items that occurs inside
another, such as the contents of a footnote inside a paragraph. This directive
is usually used inside a macro. For example, a <span class="bold"><strong>footnote</strong></span> macro could be
defined like this:
</p><pre class="literallayout">
 .macro footnote
 &amp;&lt;footnote&gt;&amp;
 .nest begin
 .endmacro
</pre><p>
At the start of a nested sequence, the current mode and paragraph state are
remembered and <span class="emphasis"><em>xfpt</em></span> then reverts to the default mode and <span class="quote">“<span class="quote">not in a paragraph</span>”</span>.
At the end of a nested sequence, if a paragraph has been started, it is
terminated, and then <span class="emphasis"><em>xfpt</em></span> reverts to the previous state.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID25">3.13 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.nonl</strong></span> directive</a></h3></div></div></div><p>This directive must be followed by a single string argument. It is processed 
as an input line without a newline at the end. This facility is useful
in macros when constructing a single data line from several text fragments. See
for example the <span class="bold"><strong>.new</strong></span> macro in the standard macros.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID26">3.14 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.pop</strong></span> directive</a></h3></div></div></div><p><span class="emphasis"><em>xfpt</em></span> keeps a stack of text strings that are manipulated by the <span class="bold"><strong>.push</strong></span> and
<span class="bold"><strong>.pop</strong></span> directives. When the end of the input is reached, any strings that
remain on the stack are popped off, processed for flags, and written to the
output. In some cases (see the <span class="bold"><strong>.push</strong></span> directive below) a warning message is 
given.
</p><p>
Each string on the stack may, optionally, be associated with an upper case
letter. If <span class="bold"><strong>.pop</strong></span> is followed by an upper case letter, it searches down the
stack for a string with the same letter. If it cannot find one, it does
nothing. Otherwise, it pops off, processes, and writes out all the strings down
to and including the one that matches.
</p><p>
If <span class="bold"><strong>.pop</strong></span> is given without a following letter, it pops one string off the
stack and writes it out. If there is nothing on the stack, an error occurs.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID27">3.15 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.push</strong></span> directive</a></h3></div></div></div><p>This directive pushes a string onto the stack. If the rest of the command line
starts with an upper case letter followed by white space or the end of the
line, that letter is associated with the string that is pushed, which consists
either of a quoted string, or the rest of the line. After a quoted string, the 
word ‘check’ may appear. In this case, if the string has not been popped off 
the stack by the end of processing, a warning message is output. This facility 
is used by the standard macros to give warnings for unclosed items such as 
<span class="bold"><strong>.ilist</strong></span>.
</p><p>
For example, the <span class="bold"><strong>.chapter</strong></span> macro contains this line:
</p><pre class="literallayout">
 .push C &amp;&lt;/chapter&gt;&amp;
</pre><p>
Earlier in the macro there is the line:
</p><pre class="literallayout">
 .pop C
</pre><p>
This arrangement ensures that any previous chapter is terminated before
starting a new one, and also when the end of the input is reached. The 
<span class="bold"><strong>.ilist</strong></span> macro contains this line:
</p><pre class="literallayout">
 .push L "&amp;&lt;/itemizedlist&gt;&amp;" check
</pre><p>
Item lists are terminatated by <span class="bold"><strong>.endlist</strong></span>, which contains:
</p><pre class="literallayout">
 .pop L
</pre><p>
However, if <span class="bold"><strong>.endlist</strong></span> is accidentally omitted (or <span class="bold"><strong>.ilist</strong></span> is accidentally
included), the appearance of ‘check’ means that a warning is issued to alert 
the user to a possible problem.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="SECTrevision">3.16 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.revision</strong></span> directive</a></h3></div></div></div><p>This directive is provided to make it easy to set the <code class="literal">revisionflag</code>
attribute on XML elements in a given portion of the document. The DocBook
specification states that the <code class="literal">revisionflag</code> attribute is common to all
elements.
</p><p>
The <span class="bold"><strong>.revision</strong></span> directive must be followed by one of the words <span class="quote">“<span class="quote">changed</span>”</span>,
<span class="quote">“<span class="quote">added</span>”</span>, <span class="quote">“<span class="quote">deleted</span>”</span>, or <span class="quote">“<span class="quote">off</span>”</span>. For any value other than <span class="quote">“<span class="quote">off</span>”</span>, it causes
the internal variable <span class="emphasis"><em>xfpt.rev</em></span> to be set to <code class="literal">revisionflag=</code> followed by
the given argument. If the argument is <span class="quote">“<span class="quote">off</span>”</span>, the internal variable is
emptied.
</p><p>
The contents of <span class="emphasis"><em>xfpt.rev</em></span> are included in every <code class="literal">&lt;para&gt;</code> element that <span class="emphasis"><em>xfpt</em></span>
generates. In addition, a number of the standard macros contain references to
<span class="emphasis"><em>xfpt.rev</em></span> in appropriate places. Thus, setting:
</p><pre class="literallayout">
 .revision changed
</pre><p>
should cause all subsequent text to be marked up with <code class="literal">revisionflag</code>
attributes, until
</p><pre class="literallayout">
 .revision off
</pre><p>
is encountered. Unfortunately, at the time of writing, not all DocBook
processing software pays attention to the <code class="literal">revisionflag</code> attribute. 
Furthermore, some software grumbles that it is <span class="quote">“<span class="quote">unexpected</span>”</span> on some elements, 
though it does still seem to process it correctly.
</p><p>
For handling the most common case (setting and unsetting <span class="quote">“<span class="quote">changed</span>”</span>), the
standard macros <span class="bold"><strong>.new</strong></span> and <span class="bold"><strong>.wen</strong></span> are provided (see section
<a class="xref" href="#SECTrevmacs" title="4.13 Revision markings">4.13</a>).
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID29">3.17 The <span xmlns="http://www.w3.org/1999/xhtml" class="bold"><strong>.set</strong></span> directive</a></h3></div></div></div><p>This directive must be followed by a name and a text string. It defines a user
variable and gives it a name. A reference to the name in the style of an XML
entity causes the string to be substituted, without further processing. For
example:
</p><pre class="literallayout">
 .set version 4.99
</pre><p>
This could be referenced as <code class="literal">&amp;version;</code>. If a variable is given the name of
an XML entity, you will not be able to refer to the XML entity, because local
variables take precedence. There is no way to delete a local variable after it
has been defined.
</p></div></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a href="#" id="CHAPstdmac">4. The standard macros for DocBook</a></h1></div></div></div><p>A set of simple macros for commonly needed DocBook features is provided in
<span class="emphasis"><em>xfpt</em></span>’s library. The standard macros assume that the standard flags are defined,
so a document that is going to use these features should start with:
</p><pre class="literallayout">
 .include stdflags
 .include stdmacs
</pre><p>
All the standard macros except <span class="bold"><strong>new</strong></span>, <span class="bold"><strong>index</strong></span>, and <span class="bold"><strong>url</strong></span> are intended to
be called as directive lines. Their names are therefore shown with a leading
dot in the discussion below.
</p><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID31">4.1 Overall setup</a></h3></div></div></div><p>There are two macros that should be used only once, at the start of the
document. The <span class="bold"><strong>.docbook</strong></span> macro has no arguments. It inserts into the output
file the standard header material for a DocBook XML file, which is:
</p><pre class="literallayout">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"&gt;
</pre><p>
The <span class="bold"><strong>.book</strong></span> macro has no arguments. It generates <code class="literal">&lt;book&gt;</code> and pushes
<code class="literal">&lt;/book&gt;</code> onto the stack so that it will be output at the end.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="idm480">4.2 Processing instructions</a></h3></div></div></div><p>XML processing instructions such as <code class="literal">&lt;?sdop</code> <code class="literal">toc_sections="no"?&gt;</code> can, of 
course, be written written literally between <code class="literal">.literal</code> <code class="literal">xml</code> and
<code class="literal">.literal</code> <code class="literal">off</code>. If there are a lot of them, this is perhaps the most
convenient approach. A macro called <span class="bold"><strong>.pi</strong></span> is provided as an easy way of
setting up a short processing instruction. Its first argument is the name of
the processor for which the instruction is intended, and its second argument is
the contents of the instruction, for example:
</p><pre class="literallayout">
 .pi sdop 'toc_sections="yes,yes,no"'
</pre><p>
This generates <code class="literal">&lt;?sdop</code> <code class="literal">toc_sections="yes,yes,no"?&gt;</code>.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID32">4.3 Chapters, sections, and subsections</a></h3></div></div></div><p>Chapters, sections, and subsections are supported by three macros that all
operate in the same way. They are <span class="bold"><strong>.chapter</strong></span>, <span class="bold"><strong>.section</strong></span>, and
<span class="bold"><strong>.subsection</strong></span>. They take either one, two, or three arguments. The first
argument is the title. If a second argument is present, and is not an empty
string, it is set as an ID, and can be used in cross-references. For example:
</p><pre class="literallayout">
 .chapter "Introduction"
</pre><p>
sets no ID, but
</p><pre class="literallayout">
 .section "A section title" "SECTdemo"
</pre><p>
can be referenced from elsewhere in the document by a phrase such as:
</p><pre class="literallayout">
 see section &amp;&lt;&lt;SECTdemo&gt;&gt;&amp;
</pre><p>
When the title of a chapter of section is being used as a running head or foot 
(for example), it may be too long to fit comfortably into the available space. 
DocBook provides the facility for a title abbreviation to be specified to deal
with this problem. If a third argument is given to one of these macros, it
causes a <code class="literal">&lt;titleabbrev&gt;</code> element to be generated. In this case, a second
argument must also be provided, but if you do not need an ID, the second
argument can be an empty string. For example:
</p><pre class="literallayout">
  .chapter "This chapter has quite a long title" "" "Long title"
</pre><p>
Where and when the abbreviation is used in place of the full title is
controlled by the stylesheet when the XML is processed.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID33">4.4 Prefaces, appendixes, and colophons</a></h3></div></div></div><p>The macros <span class="bold"><strong>.preface</strong></span>, <span class="bold"><strong>.appendix</strong></span>, and <span class="bold"><strong>.colophon</strong></span> operate in the same 
way as <span class="bold"><strong>.chapter</strong></span>, except that the first and the last have the default title
strings <span class="quote">“<span class="quote">Preface</span>”</span> and <span class="quote">“<span class="quote">Colophon</span>”</span>.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="idm518">4.5 Terminating chapters, etc.</a></h3></div></div></div><p>The macros for chapters, sections, appendixes, etc. use the stack to ensure
that each one is terminated at the correct point, without the need for an 
explicit terminator. For example, starting a new section automatically
terminates an open subsection and a previous section.
</p><p>
Occasionally, however, there is a need to force an explicit termination. The
<span class="bold"><strong>.endchapter</strong></span>, <span class="bold"><strong>.endsection</strong></span>, <span class="bold"><strong>.endsubsection</strong></span>, <span class="bold"><strong>.endpreface</strong></span>,
<span class="bold"><strong>.endappendix</strong></span>, and <span class="bold"><strong>.endcolophon</strong></span> macros provide this facility. For
example, if you want to include an XML processing instruction after a preface,
but before the start of the following chapter, you must terminate the preface
with <span class="bold"><strong>.endpreface</strong></span>. Otherwise a processing instruction that precedes the next
<span class="bold"><strong>.chapter</strong></span> will end up inside the <code class="literal">&lt;preface&gt;</code> element. You should not 
include any actual text items at these points.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID34">4.6 URL references</a></h3></div></div></div><p>The <span class="bold"><strong>url</strong></span> macro generates URL references, and is intended to be called inline
within the text that is being processed. It generates a <code class="literal">&lt;ulink&gt;</code> element,
and has either one or two arguments. The first argument is the URL, and the
second is the text that describes it. For example:
</p><pre class="literallayout">
 More details are &amp;url(http://x.example, here).
</pre><p>
This generates the following XML:
</p><pre class="literallayout">
 More details are &lt;ulink url="http://x.example"&gt;here&lt;/ulink&gt;.
</pre><p>
If the second argument is absent, the contents of the first argument are used
instead. If <span class="bold"><strong>url</strong></span> is called as a directive, there will be a newline in the 
output after <code class="literal">&lt;/ulink&gt;</code>, which in most cases (such as the example above), you 
do not want.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID35">4.7 Itemized lists</a></h3></div></div></div><p>The <span class="bold"><strong>.ilist</strong></span> macro marks the start of an itemized list, the items of which
are normally rendered with bullets or similar markings. The macro can
optionally be called with one argument, for which there is no default. If the
argument is present, it is used to add a <code class="literal">mark=</code> attribute to the
<code class="literal">&lt;itemizedlist&gt;</code> element that is generated. The mark names that can be used
depend on the software that processes the resulting XML. For HTML output,
<span class="quote">“<span class="quote">square</span>”</span> and <span class="quote">“<span class="quote">opencircle</span>”</span> work in some browsers.
</p><p>
The text for the first item follows the macro call. The start of the next item
is indicated by the <span class="bold"><strong>.next</strong></span> macro, and the end of the list by <span class="bold"><strong>.endlist</strong></span>.
For example:
</p><pre class="literallayout">
 .ilist
 This is the first item.
 .next
 This is the next item.
 .endlist
</pre><p>
There may be more than one paragraph in an item. 
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID36">4.8 Ordered lists</a></h3></div></div></div><p>The <span class="bold"><strong>.olist</strong></span> macro marks the start of an ordered list, the items of which are
numbered. If no argument is given, arabic numerals are used. One of the
following words can be given as the macro’s argument to specify the numeration:
</p><div class="literallayout">
<code class="literal">arabic     </code>   arabic numerals<br />
<code class="literal">loweralpha </code>   lower case letters<br />
<code class="literal">lowerroman </code>   lower case roman numerals<br />
<code class="literal">upperalpha </code>   upper case letters<br />
<code class="literal">upperroman </code>   upper case roman numerals<br />
</div><p>
The text for the first item follows the macro call. The start of the next item
is indicated by the <span class="bold"><strong>.next</strong></span> macro, and the end of the list by <span class="bold"><strong>.endlist</strong></span>.
For example:
</p><pre class="literallayout">
 .olist lowerroman
 This is the first item.
 .next
 This is the next item.
 .endlist
</pre><p>
There may be more than one paragraph in an item.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID37">4.9 Variable lists</a></h3></div></div></div><p>A variable list is one in which each entry is composed of a set of one or more
terms and an associated description. Typically, the terms are printed in a
style that makes them stand out, and the description is indented underneath.
The start of a variable list is indicated by the <span class="bold"><strong>.vlist</strong></span> macro, which has
one optional argument. If present, it defines a title for the list.
</p><p>
Each entry is defined by a <span class="bold"><strong>.vitem</strong></span> macro, whose arguments are the terms.
This is followed by the body of the entry. The list is terminated by the
<span class="bold"><strong>.endlist</strong></span> macro. For example:
</p><pre class="literallayout">
 .vlist "Font filename extensions"
 .vitem "TTF"
 TrueType fonts.
 .vitem "PFA" "PFB"
 PostScript fonts.
 .endlist
</pre><p>
As for the other lists, there may be more than one paragraph in an item.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID38">4.10 Nested lists</a></h3></div></div></div><p>Lists may be nested as required. Some DocBook processors automatically choose
different bullets for nested itemized lists, but others do not. The
<span class="bold"><strong>.endlist</strong></span> macro has no useful arguments. Any text that follows it is
treated as a comment. This can provide an annotation facility that may make the
input easier to understand when lists are nested.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID39">4.11 Displayed text</a></h3></div></div></div><p>In displayed text each non-directive input line generates one output line. The
<code class="literal">&lt;literallayout&gt;</code> DocBook element is used to achieve this. Two kinds of
displayed text are supported by the standard macros. They differ in their
handling of the text itself.
</p><p>
The macro <span class="bold"><strong>.display</strong></span> is followed by lines that are processed in the same way
as normal paragraphs: flags are interpreted, and so there may be font changes
and so on. The lines are processed in literal layout mode. For example:
</p><pre class="literallayout">
 .display
 &amp;`-o`&amp;   set output destination
 &amp;`-S`&amp;   set library path
 .endd
</pre><p>
The output is as follows:
</p><div class="literallayout">
 <code class="literal">-o</code>   set output destination<br />
 <code class="literal">-S</code>   set library path<br />
</div><p>
The macro <span class="bold"><strong>.code</strong></span> is followed lines that are not processed in any way, except
to turn ampersands and angle brackets into XML entities. The lines are
processed in literal text mode. In addition, <code class="literal">class="monospaced"</code> is added to
the <code class="literal">&lt;literallayout&gt;</code> element, so that the lines are displayed in a
monospaced font. For example:
</p><pre class="literallayout">
 .code
 z = sqrt(x*x + y*y);
 .endd
</pre><p>
As the examples illustrate, both kinds of display are terminated by the
<span class="bold"><strong>.endd</strong></span> macro.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID40">4.12 Block quotes</a></h3></div></div></div><p>The macro pair <span class="bold"><strong>.blockquote</strong></span> and <span class="bold"><strong>.endblockquote</strong></span> are used to wrap the
lines between them in a <code class="literal">&lt;blockquote&gt;</code> element.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="SECTrevmacs">4.13 Revision markings</a></h3></div></div></div><p>Two macros are provided to simplify setting and unsetting the <span class="quote">“<span class="quote">changed</span>”</span>
revision marking (see section <a class="xref" href="#SECTrevision" title="3.16 The .revision directive">3.16</a>). When the revised text is
substantial (for example, a complete paragraph, table, display, or section), it
can be placed between <span class="bold"><strong>.new</strong></span> and <span class="bold"><strong>.wen</strong></span>, as in this example:
</p><pre class="literallayout">
  This paragraph is not flagged as changed.
  .new
  This is a changed paragraph that contains a display:
  .display
  whatever
  .endd
  This is the next paragraph.
  .wen      
  Here is the next, unmarked, paragraph.
</pre><p>
When called like this, without an argument, in ordinary text, <span class="bold"><strong>.new</strong></span>
terminates the current paragraph, and <span class="bold"><strong>.wen</strong></span> always does so. Therefore, even
though there are no blank lines before <span class="bold"><strong>.new</strong></span> or <span class="bold"><strong>.wen</strong></span> above, the revised
text will end up in a paragraph of its own. (You can, of course, put in blank
lines if you wish.)
</p><p>
If want to indicate that just a few words inside a paragraph are revised, you
can call the <span class="bold"><strong>new</strong></span> macro with an argument. The macro can be called either as
a directive or inline:
</p><pre class="literallayout">
  This is a paragraph that has 
  .new "a few marked words" 
  within it. Here are &amp;new(some more) marked words.
</pre><p>
The effect of this is to generate a <code class="literal">&lt;phrase&gt;</code> XML element with the
<code class="literal">revisionflag</code> attribute set. The <span class="bold"><strong>.wen</strong></span> macro is not used in this case.
</p><p>
You can use the <span class="bold"><strong>.new</strong></span>/<span class="bold"><strong>.wen</strong></span> macro pair to generate a <code class="literal">&lt;phrase&gt;</code> element 
inside a section of displayed text. For example:
</p><pre class="literallayout">
  .display
  This line is not flagged as changed.
  .new
  This line is flagged as changed.
  .wen
  This line is not flagged as changed.
  .endd
</pre><p>
This usage works with both <span class="bold"><strong>.display</strong></span> and <span class="bold"><strong>.code</strong></span>. Within a <span class="bold"><strong>.display</strong></span> 
section you can also call <span class="bold"><strong>.new</strong></span> with an argument, either as a directive or 
inline. This does not work for <span class="bold"><strong>.code</strong></span> because its lines are processed in
literal text mode.
</p><p>
If you want to add revision indications to part of a table, you must use an
inline call of <span class="bold"><strong>new</strong></span> within an argument of the <span class="bold"><strong>.row</strong></span> macro (see below).
This is the only usage that works in this case.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID42">4.14 Informal tables</a></h3></div></div></div><p>The <span class="bold"><strong>.itable</strong></span> macro starts an informal (untitled) table with some basic
parameterization. If you are working on a large document that has many tables
with the same parameters, the best approach is to define your own table macros,
possibly calling the standard one with specific arguments.
</p><p>
The <span class="bold"><strong>.itable</strong></span> macro has four basic arguments:
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
The frame requirement for the table, which may be one of the words <span class="quote">“<span class="quote">all</span>”</span>,
<span class="quote">“<span class="quote">bottom</span>”</span>, <span class="quote">“<span class="quote">none</span>”</span> (the default), <span class="quote">“<span class="quote">sides</span>”</span>, <span class="quote">“<span class="quote">top</span>”</span>, or <span class="quote">“<span class="quote">topbot</span>”</span>.
</p></li><li class="listitem"><p>
The <span class="quote">“<span class="quote">colsep</span>”</span> value for the table. The default is <span class="quote">“<span class="quote">0</span>”</span>, meaning no vertical
separator lines between columns. The value <span class="quote">“<span class="quote">1</span>”</span> requests vertical separator
lines.
</p></li><li class="listitem"><p>
The <span class="quote">“<span class="quote">rowsep</span>”</span> value for the table. The default is <span class="quote">“<span class="quote">0</span>”</span>, meaning no horizontal
lines between rows. The value <span class="quote">“<span class="quote">1</span>”</span> requests horizontal separator lines.
</p></li><li class="listitem"><p>
The number of columns.
</p></li></ol></div><p>
These arguments must be followed by two arguments for each column. The first
specifies the column width, and the second its alignment. A column width can be
specified as an absolute dimension such as 36pt or 2in, or as a proportional
measure, which has the form of a number followed by an asterisk. The two forms
can be mixed – see the DocBook specification for details.
</p><p>
Straightforward column alignments can be specified as <span class="quote">“<span class="quote">center</span>”</span>, <span class="quote">“<span class="quote">left</span>”</span>, or
<span class="quote">“<span class="quote">right</span>”</span>. DocBook also has some other possibilities, but sadly they do not 
seem to include <span class="quote">“<span class="quote">centre</span>”</span>.
</p><p>
Each row of the table is specified using a <span class="bold"><strong>.row</strong></span> macro; the entries in
the row are the macros’s arguments. The table is terminated by <span class="bold"><strong>.endtable</strong></span>,
which has no arguments. For example:
</p><pre class="literallayout">
 .itable all 1 1 2 1in left 2in center
 .row "cell 11" "cell 12"
 .row "cell 21" "cell 22"
 .endtable
</pre><p>
This specifies a framed table, with both column and row separator lines. There
are two columns: the first is one inch wide and left aligned, and the second is
two inches wide and centred. There are two rows. The resulting table looks like
this:
</p><div class="informaltable"><table class="informaltable" border="1"><colgroup><col width="1in" align="left" /><col width="2in" align="center" /></colgroup><tbody><tr><td align="left">cell 11</td><td align="center">cell 12</td></tr><tr><td align="left">cell 21</td><td align="center">cell 22</td></tr></tbody></table></div><p>
The <span class="bold"><strong>.row</strong></span> macro does not set the <code class="literal">revisionflag</code> attribute in the 
<code class="literal">&lt;entry&gt;</code> elements that it generates because this appears to be ignored by 
all current XML processors. However, you can use an inline call of the <span class="bold"><strong>new</strong></span> 
macro within an entry to generate a <code class="literal">&lt;phrase&gt;</code> element with <code class="literal">revisionflag</code> 
set.
</p></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID43">4.15 Formal tables</a></h3></div></div></div><p>The <span class="bold"><strong>.table</strong></span> macro starts a formal table, that is, a table that has a title, 
and which can be cross referenced. The first argument of this macro is the 
table’s title; the second is an identifier for cross-referencing. If you are 
not going to reference the table, an empty string must be supplied. From the 
third argument onwards, the arguments are identical to the <span class="bold"><strong>.itable</strong></span> macro.
For example:
</p><pre class="literallayout">
 .table "A title for the table" "" all 1 1 2 1in left 2in center
 .row "cell 11" "cell 12"
 .row "cell 21" "cell 22"
 .endtable
</pre></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID44">4.16 Figures and images</a></h3></div></div></div><p>A figure is enclosed between <span class="bold"><strong>.figure</strong></span> and <span class="bold"><strong>.endfigure</strong></span> macros. The first 
argument of <span class="bold"><strong>.figure</strong></span> provides a title for the figure. The second is 
optional; if present, it is a tag for references to the figure.
</p><p>
A figure normally contains an image. The <span class="bold"><strong>.image</strong></span> macro can be used in simple 
cases. It generates a <code class="literal">&lt;mediaobject&gt;</code> element containing an
<code class="literal">&lt;imageobject&gt;</code>. The first argument is the name of the file containing the
image. The remaining arguments are optional; an empty string must be
supplied as a placeholder when one that is not required is followed by one that
is set.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
The second argument specifies a scaling factor for the image, as a percentage. 
Thus, a value of 50 reduces the image to half size.
</p></li><li class="listitem"><p>
The third argument specifies an alignment for the image. It must be one of 
<code class="literal">left</code> (default), <code class="literal">right</code> or <code class="literal">center</code> (or even <code class="literal">centre</code> if the
DocBook processor you are using can handle it).
</p></li><li class="listitem"><p>
The fourth and fifth arguments specify the depth and width, respectively. How 
these values are handled depends on the processing software.
</p></li></ul></div><p>
Here is an example of the input for a figure, with all the image options 
defaulted:
</p><pre class="literallayout">
 .figure "My figure's title" "FIGfirst"
 .image figure01.eps
 .endfigure
</pre><p>
Here is another example, where the figure is reduced to 80% and centred:
</p><pre class="literallayout">
 .figure "A reduced figure"
 .image figure02.eps 80 center
 .endfigure  
</pre></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID45">4.17 Footnotes</a></h3></div></div></div><p>Footnotes can be specified between <span class="bold"><strong>.footnote</strong></span> and <span class="bold"><strong>.endnote</strong></span> macros. 
Within a footnote there can be any kind of text item, including displays and 
tables. When a footnote occurs in the middle of a paragraph, paired flags 
must not straddle the footnote. This example is wrong:
</p><pre class="literallayout">
 The &amp;'quick
 .footnote
 That's really fast.
 .endnote
 brown'&amp; fox.
</pre><p>
The correct markup for this example is:
</p><pre class="literallayout">
 The &amp;'quick'&amp;
 .footnote
 That's really fast.
 .endnote
 &amp;'brown'&amp; fox.
</pre></div><div class="section"><div class="titlepage"><div><div><h3 xmlns="" class="title"><a xmlns="http://www.w3.org/1999/xhtml" href="#" id="ID46">4.18 Indexes</a></h3></div></div></div><p>The <span class="bold"><strong>.index</strong></span> macro generates <code class="literal">&lt;indexterm&gt;</code> elements (index entries) in the
output. It takes one or two arguments. The first is the text for the primary
index term, and the second, if present, specifies a secondary index term. This
macro can be called either from a directive line, or inline. However, it is
mostly called as a directive, at the start of a relevant paragraph. For
example:
</p><pre class="literallayout">
 .index goose "wild chase"
 The chasing of wild geese...
</pre><p>
You can generate <span class="quote">“<span class="quote">see</span>”</span> and <span class="quote">“<span class="quote">see also</span>”</span> index entries by using <span class="bold"><strong>.index-see</strong></span> 
and <span class="bold"><strong>.index-seealso</strong></span> instead of <span class="bold"><strong>.index</strong></span>. The first argument of these 
macros is the text for the <span class="quote">“<span class="quote">see</span>”</span>. For example:
</p><pre class="literallayout">
 .index-see "chase" "wild goose"
</pre><p>
This generates:
</p><pre class="literallayout">
 &lt;indexterm&gt;
 &lt;primary&gt;wild goose&lt;/primary&gt;
 &lt;see&gt;chase&lt;/see&gt;
 &lt;/indexterm&gt;
</pre><p>
If you want to generate an index entry for a range of pages, you can use the 
<span class="bold"><strong>.index-from</strong></span> and <span class="bold"><strong>.index-to</strong></span> macros. The first argument of each of them is 
an ID that ties them together. The second and third arguments of 
<span class="bold"><strong>.index-from</strong></span> are the primary and secondary index items. For example:
</p><pre class="literallayout">
 .index-from "ID5" "indexes" "handling ranges"
 ... &lt;lines of text&gt; ...
 .index-to "ID5"
</pre><p>
The <span class="bold"><strong>.makeindex</strong></span> macro should be called at the end of the document, at the
point where you want an index to be generated. It can have up to two
arguments. The first is the title for the index, for which the default is
<span class="quote">“<span class="quote">Index</span>”</span>. The second, if present, causes a <code class="literal">role=</code> attribute to be added to
the <code class="literal">&lt;index&gt;</code> element that is generated. For this to be useful, you need to
generate <code class="literal">&lt;indexterm&gt;</code> elements that have similar <code class="literal">role=</code> attributes. The
standard <span class="bold"><strong>index</strong></span> macro cannot do this. If you want to generate multiple
indexes using this mechanism, it is best to define your own macros for each
index type. For example:
</p><pre class="literallayout">
 .macro cindex
 &amp;&lt;indexterm role="concept"&gt;&amp;
 &amp;&lt;primary&gt;&amp;$1&amp;&lt;/primary&gt;&amp;
 .arg 2
 &amp;&lt;secondary&gt;&amp;$2&amp;&lt;/secondary&gt;&amp;
 .endarg
 &amp;&lt;/indexterm&gt;&amp;
 .endmacro
</pre><p>
This defines a <span class="bold"><strong>.cindex</strong></span> macro for the <span class="quote">“<span class="quote">concept</span>”</span> index. At the end of the 
document you might have:
</p><pre class="literallayout">
 .makeindex "Concept index" "concept"
 .makeindex
</pre><p>
As long as the processing software can handle multiple indexes, this causes two
indexes to be generated. The first is entitled <span class="quote">“<span class="quote">Concept index</span>”</span>, and contains 
only those index entries that were generated by the <span class="bold"><strong>.cindex</strong></span> macro. The 
second contains all index entries.
</p></div></div></div></body></html>