AsciiDoc User Guide
===================
Stuart Rackham <srackham@gmail.com>
:Author Initials: SJR

AsciiDoc is a text document format for writing documentation,
articles, manuals, books and UNIX man pages. AsciiDoc files can be
translated to HTML and DocBook markups using the asciidoc(1) command.
AsciiDoc is highly configurable: both the AsciiDoc source file syntax
and the backend output markups (which can be almost any type of
SGML/XML markup) can be customized and extended by the user.


Introduction
------------
**********************************************************************
This is an overly large document, it probably needs to be refactored
into a Tutorial, Quick Reference and Formal Reference.

If you're new to AsciiDoc read this section and the <<X6,Getting
Started>> section and take a look at the example AsciiDoc `.txt`
source files in the distribution `doc` directory.
**********************************************************************

Plain text is the most universal electronic document format, no matter
what computing environment you use, you can always read and write
plain text documentation. But for many applications plain text is not
a viable presentation format.  HTML, PDF and roff (roff is used for
man pages) are the most widely used UNIX presentation formats.
DocBook is a popular UNIX documentation markup format which can be
translated to HTML, PDF and other presentation formats.

AsciiDoc is a plain text human readable/writable document format that
can be translated to DocBook or HTML using the asciidoc(1) command.
You can then either use asciidoc(1) generated HTML directly or run
asciidoc(1) DocBook output through your favorite DocBook toolchain or
use the AsciiDoc a2x(1) toolchain wrapper to produce PDF, EPUB, DVI,
LaTeX, PostScript, man page, HTML and text formats.

The AsciiDoc format is a useful presentation format in its own right:
AsciiDoc files are unencumbered by markup and are easily viewed,
proofed and edited.

AsciiDoc is light weight: it consists of a single Python script and a
bunch of configuration files. Apart from asciidoc(1) and a Python
interpreter, no other programs are required to convert AsciiDoc text
files to DocBook or HTML. See <<X11,Example AsciiDoc Documents>>
below.

You write an AsciiDoc document the same way you would write a normal
text document, there are no markup tags or arcane notations. Built-in
AsciiDoc formatting rules have been kept to a minimum and are
reasonably obvious.

Text markup conventions tend to be a matter of (often strong) personal
preference: if the default syntax is not to your liking you can define
your own by editing the text based asciidoc(1) configuration files.
You can create your own configuration files to translate AsciiDoc
documents to almost any SGML/XML markup.

asciidoc(1) comes with a set of configuration files to translate
AsciiDoc articles, books or man pages to HTML or DocBook backend
formats.

.My AsciiDoc Itch
**********************************************************************
DocBook has emerged as the de facto standard Open Source documentation
format. But DocBook is a complex language, the marked up text is
difficult to read and even more difficult to write directly -- I found
I was spending more time typing markup tags, consulting reference
manuals and fixing syntax errors, than I was writing the
documentation.
**********************************************************************


[[X6]]
Getting Started
---------------
Installing AsciiDoc
~~~~~~~~~~~~~~~~~~~
See the `README` and `INSTALL` files for install prerequisites and
procedures. Packagers take a look at <<X38,Appendix B: Packager
Notes>>.

[[X11]]
Example AsciiDoc Documents
~~~~~~~~~~~~~~~~~~~~~~~~~~
The best way to quickly get a feel for AsciiDoc is to view the
AsciiDoc web site and/or distributed examples:

- Take a look at the linked examples on the AsciiDoc web site home
  page http://www.methods.co.nz/asciidoc/.  Press the 'Page Source'
  sidebar menu item to view corresponding AsciiDoc source.
- Read the `.txt` source files in the distribution `./doc` directory
  in conjunction with the corresponding HTML and DocBook XML files.


AsciiDoc Document Types
-----------------------
There are three types of AsciiDoc documents: article, book and
manpage. All document types share the same AsciiDoc format with some
minor variations.

Use the asciidoc(1) `-d` (`--doctype`) option to specify the AsciiDoc
document type -- the default document type is 'article'.

By convention the `.txt` file extension is used for AsciiDoc document
source files.

article
~~~~~~~
Used for short documents, articles and general documentation.  See the
AsciiDoc distribution `./doc/article.txt` example.

AsciiDoc defines standard DocBook article frontmatter and backmatter
<<X93,section markup templates>> (appendix, abstract, bibliography,
glossary, index).

book
~~~~
Books share the same format as articles; in addition there is the
option to add level 0 book part sections.

Book documents will normally be used to produce DocBook output since
DocBook processors can automatically generate footnotes, table of
contents, list of tables, list of figures, list of examples and
indexes.

AsciiDoc defines standard DocBook book frontmatter and backmatter
<<X93,section markup templates>> (appendix, dedication, preface,
bibliography, glossary, index, colophon).

.Example book documents
Book::
  The `./doc/book.txt` file in the AsciiDoc distribution.

Multi-part book::
  The `./doc/book-multi.txt` file in the AsciiDoc distribution.

manpage
~~~~~~~
Used to generate UNIX manual pages.  AsciiDoc manpage documents
observe special header title and section naming conventions -- see the
<<X1,Manpage Documents>> section for details.

AsciiDoc defines the 'synopsis' <<X93,section markup template>> to
generate the DocBook `refsynopsisdiv` section.

See also the asciidoc(1) man page source (`./doc/asciidoc.1.txt`) from
the AsciiDoc distribution.


[[X5]]
AsciiDoc Backends
-----------------
The asciidoc(1) command translates an AsciiDoc formatted file to the
backend format specified by the `-b` (`--backend`) command-line
option. asciidoc(1) itself has little intrinsic knowledge of backend
formats, all translation rules are contained in customizable cascading
configuration files. Backend specific attributes are listed in
<<X88,Appendix H>>.

AsciiDoc ships with the following predefined backend output formats:

docbook
~~~~~~~
AsciiDoc generates the following DocBook document types: article, book
and refentry (corresponding to the AsciiDoc 'article', 'book' and
'manpage' document types).

DocBook documents are not designed to be viewed directly.  Most Linux
distributions come with conversion tools (collectively called a
toolchain) for <<X12,converting DocBook files>> to presentation
formats such as Postscript, HTML, PDF, EPUB, DVI, PostScript, LaTeX,
roff (the native man page format), HTMLHelp, JavaHelp and text.

The AsciiDoc <<X86,Preamble>> element generates a DocBook book
'preface'.

[[X33]]
xhtml11
~~~~~~~
The default asciidoc(1) backend is `xhtml11` which generates XHTML 1.1
markup styled with CSS2. Default output file have a `.html` extension.
'xhtml11' document generation is influenced by the following
optional attributes (the default behavior is to generate XHTML with no
section numbers, embedded CSS and no linked admonition icon images):

[[X35]]
Stylesheets
^^^^^^^^^^^
AsciiDoc XHTML output is styled using CSS2 stylesheets from the
distribution `./stylesheets/` directory.

[IMPORTANT]
=====================================================================
All browsers have CSS quirks, but Microsoft's IE6 has so many
omissions and errors that the `xhtml11-quirks.css` stylesheet and
`xhtml11-quirks.conf` configuration files are included during XHTML
backend processing to to implement workarounds for IE6. If you don't
use IE6 then the quirks stylesheet and configuration files can be
omitted using the `--attribute quirks!` command-line option.
=====================================================================

Default 'xhtml11' stylesheets:

`./stylesheets/xhtml11.css`::
    The main stylesheet.

`./stylesheets/xhtml11-manpage.css`::
    Tweaks for manpage document type generation.

`./stylesheets/xhtml11-quirks.css`::
    Stylesheet modifications to work around IE6 browser
    incompatibilities.

Use the 'theme' attribute to select an alternative set of stylesheets.
For example, the command-line option `-a theme=foo` will use
stylesheets `foo.css`, `foo-manpage.css` and `foo-quirks.css` instead
of the default stylesheets.

Use the 'stylesheet' attribute to include an additional stylesheet in
XHTML documents.  For example, the command-line option `-a
stylesheet=newsletter.css` will use stylesheets `newsletter.css`.

html4
~~~~~
This backend generates plain (unstyled) HTML 4.01 Transitional markup.


Document Structure
------------------
An AsciiDoc document consists of a series of <<X8,block elements>>
starting with an optional document Header, followed by an optional
Preamble, followed by zero or more document Sections.

Almost any combination of zero or more elements constitutes a valid
AsciiDoc document: documents can range from a single sentence to a
multi-part book.

Block Elements
~~~~~~~~~~~~~~
Block elements consist of one or more lines of text and may contain
other block elements.

The AsciiDoc block structure can be informally summarized as follows
footnote:[This is a rough structural guide, not a rigorous syntax
definition]:

  Document      ::= (Header?,Preamble?,Section*)
  Header        ::= (Title,(AuthorLine,RevisionLine?)?)
  AuthorLine    ::= (FirstName,(MiddleName?,LastName)?,EmailAddress?)
  RevisionLine  ::= (Revision?,Date)
  Preamble      ::= (SectionBody)
  Section       ::= (Title,SectionBody?,(Section)*)
  SectionBody   ::= ((BlockTitle?,Block)|BlockMacro)+
  Block         ::= (Paragraph|DelimitedBlock|List|Table)
  List          ::= (BulletedList|NumberedList|LabeledList|CalloutList)
  BulletedList  ::= (ListItem)+
  NumberedList  ::= (ListItem)+
  CalloutList   ::= (ListItem)+
  LabeledList   ::= (ListEntry)+
  ListEntry     ::= (ListLabel,ListItem)
  ListLabel     ::= (ListTerm+)
  ListItem      ::= (ItemText,(List|ListParagraph|ListContinuation)*)

Where:

- '?' implies zero or one occurrence, '+' implies one or more
  occurrences, '*' implies zero or more occurrences.
- All block elements are separated by line boundaries.
- `BlockId`, `AttributeEntry` and `AttributeList` block elements (not
  shown) can occur almost anywhere.
- There are a number of document type and backend specific
  restrictions imposed on the block syntax.
- The following elements cannot contain blank lines: Header, Title,
  Paragraph, ItemText.
- A ListParagraph is a Paragraph with its 'listelement' option set.
- A ListContinuation is a <<X15,list continuation element>>.

Header
~~~~~~
The Header contains a document title plus optional authorship and
revision information:

- The Header is optional, but if it is used it must start with a
  document <<X17,title>>.
- The header can be preceded by comments and <<X18,attribute
  entries>>.
- Optional Author and Revision lines immediately follow the header
  title.
- The header can include attribute entries.
- The document header must be separated from the remainder of the
  document by one or more blank lines.

Here's an example AsciiDoc document header:

  Writing Documentation using AsciiDoc
  ====================================
  Joe Bloggs <jbloggs@mymail.com>
  v2.0, February 2003:
  Rewritten for version 2 release.

The author line contains the author's name optionally followed by the
author's email address. The author's name consists of a first name
followed by optional middle and last names separated by white space.
Multi-word first, middle and last names can be entered in the header
author line using the underscore as a word separator. The email
address comes last and must be enclosed in angle <> brackets. Author
names cannot contain angle <> bracket characters.  Here a some
examples of author lines:

  Joe Bloggs <jbloggs@mymail.com>
  Joe Bloggs
  Vincent Willem van_Gogh

The optional header revision line follows the author line.  The
revision line can be one of two formats:

. An optional document revision number followed by an optional
  revision date followed by an optional revision remark:

  * If the revision number is specified it must be followed by a
    comma.
  * The revision number must contain at least one numeric character.
  * Any non-numeric characters preceding the first numeric character
    will be dropped.
  * If a revision remark is specified it must be preceded by a colon.
    The revision remark extends from the colon up to the next blank
    line or attribute entry and is subject to normal text
    substitutions.
  * If a revision number or remark has been set but the revision date
    has not been set then the revision date is set to the value of the
    'docdate' attribute.

. An RCS/CSV/SVN $Id$ marker (if an $Id$ revision marker is used the
  header author line can be omitted).

Here a some examples of header revision lines:

  v2.0, February 2003
  February 2003
  v2.0,
  v2.0, February 2003: Rewritten for version 2 release.
  February 2003: Rewritten for version 2 release.
  v2.0,: Rewritten for version 2 release.
  :Rewritten for version 2 release.

You can override or set header parameters by passing 'revnumber',
'revremark', 'revdate', 'email', 'author', 'authorinitials',
'firstname' and 'lastname' attributes using the asciidoc(1) `-a`
(`--attribute`) command-line option. For example:

  $ asciidoc -a revdate=2004/07/27 article.txt

The 'revnumber' attribute can be an RCS/CSV/SVN $Id$ marker.
Attributes can also be added to the header for substitution in the
header template with <<X18,Attribute Entry>> elements.

[[X87]]
Additional document header information
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DocBook defines numerous elements for document meta-data, for example:
copyrights, document history and authorship information.  The AsciiDoc
header syntax provides for basic revision and author information --
additional information such as copyrights, document history authorship
details can be optionally included from a separate document
information. The document information file can contain any DocBook
elements that are allowed inside the DocBook 'articleinfo' and
'bookinfo' elements:

- The document information file must be in the same directory as the
  source document and must be named like `<docname>-docinfo.xml`.  For
  example, if the source document is called `mydoc.txt` then the
  document information file would be named `mydoc-docinfo.xml`.
- The document information file will be included in the DocBook output
  if the `docinfo` attribute is defined, for example:

  $ asciidoc -a docinfo -b docbook mydoc.txt

- See the `./doc/article-docinfo.xml` example that comes with the
  AsciiDoc distribution.
- Similarly AsciiDoc will include a docinfo file named like
  `<docname>-docinfo.html` (if it exists) into HTML backend outputs.
  In the case of HTML outputs however it's usually easier to put
  AsciiDoc markup in your source file directly after the header.

NOTE: DocBook has a rich set of meta data elements, just how many of
these elements are rendered is DocBook processor dependent.

[[X86]]
Preamble
~~~~~~~~
The Preamble is an optional untitled section body between the document
Header and the first Section title.

Sections
~~~~~~~~
In addition to the document title (level 0), AsciiDoc supports four
section levels: 1 (top) to 4 (bottom).  Section levels are delimited
by section <<X17,titles>>.  Sections are translated using
configuration file markup templates. AsciiDoc generates the following
<<X60,intrinsic attributes>> specifically for use in section markup
templates:

level::
The `level` attribute is the section level number, it is normally just
the <<X17,title>> level number (1..4). However, if the `leveloffset`
attribute is defined it will be added to the `level` attribute. The
`leveloffset` attribute is useful for <<X90,combining documents>>.

sectnum::
The `-n` (`--section-numbers`) command-line option generates the
`sectnum` (section number) attribute.  The `sectnum` attribute is used
for section numbers in HTML outputs (DocBook section numbering are
handled automatically by the DocBook toolchain commands).

[[X93]]
Section markup templates
^^^^^^^^^^^^^^^^^^^^^^^^
Section markup templates specify output markup and are defined in
AsciiDoc configuration files.  Section markup template names are
derived as follows (in order of precedence):

1. From the title's first positional attribute or 'template'
   attribute to the name of a configuration file template. For
   example, the following three section titles are functionally
   equivalent:
+
.....................................................................
[[terms]]
[glossary]
List of Terms
-------------

["glossary",id="terms"]
List of Terms
-------------

[template="glossary",id="terms"]
List of Terms
-------------
.....................................................................

2. When the title text matches a configuration file
   <<X16,`[specialsections]`>> entry.
3. If neither of the above the default `sect<level>` template is used
   (where `<level>` is a number from 1 to 4).

In addition to the normal section template names ('sect1', 'sect2',
'sect3', 'sect4') AsciiDoc has the following templates for
frontmatter, backmatter and other special sections: 'abstract',
'preface', 'colophon', 'dedication', 'glossary', 'bibliography',
'synopsis', 'appendix', 'index'.  These special section templates
generate the corresponding Docbook elements; for HTML outputs they
default to the 'sect1' section template.

Section IDs
^^^^^^^^^^^
Section IDs are auto-generated from section titles if the `sectids`
attribute is defined (the default behavior). The primary purpose of
this feature is to ensure persistence of table of contents links
(permalinks): missing section IDs are generated dynamically by the
JavaScript TOC generator *after* the page is loaded. If you link to a
dynamically generated TOC address the page will load but the browser
will ignore the (as yet ungenerated) section ID.

The IDs are generated by the following algorithm:

- Replace all non-alphanumeric title characters with underscores.
- Strip leading or trailing underscores.
- Convert to lowercase.
- Prepend the `idprefix` attribute (so there's no possibility of name
  clashes with existing document IDs). Prepend an underscore if the
  `idprefix` attribute is not defined.
- A numbered suffix (`_2`, `_3` ...) is added if a same named
  auto-generated section ID exists.

For example the title 'Jim's House' would generate the ID
`_jim_s_house`.

[[X16]]
Special Section Titles
^^^^^^^^^^^^^^^^^^^^^^
AsciiDoc has a mechanism for mapping predefined section titles
auto-magically to specific markup templates. For example a title
'Appendix A: Code Reference' will automatically use the 'appendix'
<<X93,section markup template>>. The mappings from title to template
name are specified in `[specialsections]` sections in the Asciidoc
language configuration files (`lang-*.conf`).  Section entries are
formatted like:

  <title>=<template>

`<title>` is a Python regular expression and `<template>` is the name
of a configuration file markup template section. If the `<title>`
matches an AsciiDoc document section title then the backend output is
marked up using the `<template>` markup template (instead of the
default `sect<level>` section template). The `{title}` attribute value
is set to the value of the matched regular expression group named
'title', if there is no 'title' group `{title}` defaults to the whole
of the AsciiDoc section title. If `<template>` is blank then any
existing entry with the same `<title>` will be deleted.

.Special section titles vs. explicit template names
*********************************************************************
AsciiDoc has two mechanisms for specifying non-default section markup
templates: you can specify the template name explicitly (using the
'template' attribute) or indirectly (using 'special section titles').
Specifying a <<X93,section template>> attribute explicitly is
preferred.  Auto-magical 'special section titles' have the following
drawbacks:

- They are non-obvious, you have to know the exact matching
  title for each special section on a language by language basis.
- Section titles are predefined and can only be customised with a
  configuration change.
- The implementation is complicated by multiple languages: every
  special section title has to be defined for each language (in each
  of the `lang-*.conf` files).

Specifying special section template names explicitly does add more
noise to the source document (the 'template' attribute declaration),
but the intention is obvious and the syntax is consistent with other
AsciiDoc elements c.f.  bibliographic, Q&A and glossary lists.

Special section titles have been deprecated but are retained for
backward compatibility.

*********************************************************************

Inline Elements
~~~~~~~~~~~~~~~
<<X34,Inline document elements>> are used to markup character
formatting and various types of text substitution. Inline elements and
inline element syntax is defined in the asciidoc(1) configuration
files.

Here is a list of AsciiDoc inline elements in the (default) order in
which they are processed:

Special characters::
        These character sequences escape special characters used by
        the backend markup (typically "<", ">", and "&"). See
        `[specialcharacters]` configuration file sections.

Quotes::
        Characters that markup words and phrases; usually for
        character formatting. See `[quotes]` configuration file
        sections.

Special Words::
        Word or word phrase patterns singled out for markup without
        the need for further annotation.  See `[specialwords]`
        configuration file sections.

Replacements::
        Each Replacement defines a word or word phrase pattern to
        search for along with corresponding replacement text. See
        `[replacements]` configuration file sections.

Attributes::
        Document attribute names enclosed in braces (attribute
        references) are replaced by the corresponding attribute value.

Inline Macros::
        Inline macros are replaced by the contents of parametrized
        configuration file sections.


Document Processing
-------------------
The AsciiDoc source document is read and processed as follows:

1. The document 'Header' is parsed, header parameter values are
   substituted into the configuration file `[header]` template section
   which is then written to the output file.
2. Each document 'Section' is processed and its constituent elements
   translated to the output file.
3. The configuration file `[footer]` template section is substituted
   and written to the output file.

When a block element is encountered asciidoc(1) determines the type of
block by checking in the following order (first to last): (section)
Titles, BlockMacros, Lists, DelimitedBlocks, Tables, AttributeEntrys,
AttributeLists, BlockTitles, Paragraphs.

The default paragraph definition `[paradef-default]` is last element
to be checked.

Knowing the parsing order will help you devise unambiguous macro, list
and block syntax rules.

Inline substitutions within block elements are performed in the
following default order:

1. Special characters
2. Quotes
3. Special words
4. Replacements
5. Attributes
6. Inline Macros
7. Replacements2

The substitutions and substitution order performed on
Title, Paragraph and DelimitedBlock elements is determined by
configuration file parameters.


Text Formatting
---------------
[[X51]]
Quoted Text
~~~~~~~~~~~
Words and phrases can be formatted by enclosing inline text with
quote characters:

_Emphasized text_::
        Word phrases \'enclosed in single quote characters' (acute
        accents) or \_underline characters_ are emphasized.

*Strong text*::
        Word phrases \*enclosed in asterisk characters* are rendered
        in a strong font (usually bold).

[[X81]]+Monospaced text+::
        Word phrases \+enclosed in plus characters+ are rendered in a
        monospaced font.  Word phrases \`enclosed in backtick
        characters` (grave accents) are also rendered in a monospaced
        font but in this case the enclosed text is rendered literally
        and is not subject to further expansion (see <<X80,inline
        literal>>).

`Single quoted text'::
        Phrases enclosed with a \`single grave accent to the left and
        a single acute accent to the right' are rendered in single
        quotation marks.

``Double quoted text''::
        Phrases enclosed with \\``two grave accents to the left and
        two acute accents to the right'' are rendered in quotation
        marks.

#Unquoted text#::
        Placing \#hashes around text# does nothing, it is a mechanism
        to allow inline attributes to be applied to otherwise
        unformatted text (see example below).

.Quoted text behavior
- Quoting cannot be overlapped.
- Different quoting types can be nested.
- To suppress quoted text formatting place a backslash character
  immediately in front of the leading quote character(s). In the case
  of ambiguity between escaped and non-escaped text you will need to
  escape both leading and trailing quotes, in the case of
  multi-character quotes you may even need to escape individual
  characters.

Quoted text can be prefixed with an <<X21,attribute list>>:

. Setting the AsciiDoc 'role' attribute will enclose DocBook markup in
  a 'phrase' element and HTML markup in a 'span' element. For example
  this AsciiDoc: `[role="foo"]'Hello World'` generates this DocBook:
  `<phrase role="foo"><emphasis>Hello World</emphasis></phrase>` and
  this HTML: `<span class="foo"><em>Hello World</em></span>`

. You can set the font color, background color and size using the
  first three positional attribute arguments (HTML outputs only). The
  first argument is the text color; the second the background color;
  the third is the font size. Colors are valid CSS colors and the font
  size is a number which treated as em units. Here are some examples:

  [red]#Red text#.
  [,yellow]*bold text on a yellow background*.
  [blue,#b0e0e6]+Monospaced blue text on a light blue background+
  [,,2]#Double sized text#.

New quotes can be defined by editing asciidoc(1) configuration files.
See the <<X7,Configuration Files>> section for details.

[[X52]]
Constrained and Unconstrained Quotes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
There are actually two types of quotes:

Constrained quotes
++++++++++++++++++
Quote text that must be bounded by white space or commonly adjoining
punctuation characters. These are the most commonly used type of
quote.

Unconstrained quotes
++++++++++++++++++++
Unconstrained quotes have no boundary constraints and can be placed
anywhere within inline text. For consistency and to make them easier
to remember unconstrained quotes are double-ups of the `_`, `*`, `+`
and `#` constrained quotes:

  __unconstrained emphasized text__
  **unconstrained strong text**
  ++unconstrained monospaced text++
  ##unconstrained unquoted text##

The following example emboldens the letter F:

  **F**ile Open...

Superscripts and Subscripts
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Put \^carets on either^ side of the text to be superscripted, put
\~tildes on either side~ of text to be subscripted.  For example, the
following line:

  e^&#960;i^+1 = 0. H~2~O and x^10^. Some ^super text^
  and ~some sub text~

Is rendered like:

e^&#960;i^+1 = 0. H~2~O and x^10^. Some ^super text^
and ~some sub text~

Superscripts and subscripts are implemented as <<X52,unconstrained
quotes>> so they can be escaped with a leading backslash and prefixed
with with an attribute list.

Line Breaks
~~~~~~~~~~~
A plus character preceded by at least one space character at the end
of a non-blank line forces a line break. It generates a line break
(`br`) tag for HTML outputs and a custom XML `asciidoc-br` processing
instruction for DocBook outputs. The `asciidoc-br` processing
instruction is handled by <<X43,a2x(1)>>.

Page Breaks
~~~~~~~~~~~
A line of three or more less-than (`<<<`) characters will generate a
hard page break in DocBook and printed HTML outputs.  It uses the CSS
`page-break-after` property for HTML outputs and a custom XML
`asciidoc-pagebreak` processing instruction for DocBook outputs. The
`asciidoc-pagebreak` processing instruction is handled by
<<X43,a2x(1)>>. Hard page breaks are sometimes handy but as a general
rule you should let your page processor generate page breaks for you.

Rulers
~~~~~~
A line of three or more apostrophe characters will generate a ruler
line.  It generates a ruler (`hr`) tag for HTML outputs and a custom
XML `asciidoc-hr` processing instruction for DocBook outputs. The
`asciidoc-hr` processing instruction is handled by <<X43,a2x(1)>>.

Tabs
~~~~
By default tab characters input files will translated to 8 spaces. Tab
expansion is set with the 'tabsize' entry in the configuration file
`[miscellaneous]` section and can be overridden in included files by
setting a 'tabsize' attribute in the `include` macro's attribute list.
For example:

  include::addendum.txt[tabsize=2]

The tab size can also be set using the attribute command-line option,
for example `--attribute tabsize=4`

Replacements
~~~~~~~~~~~~
The following replacements are defined in the default AsciiDoc
configuration:

  (C) copyright, (TM) trademark, (R) registered trademark,
  -- em dash, ... ellipsis, -> right arrow, <- left arrow, => right
  double arrow, <= left double arrow.

Which are rendered as:

(C) copyright, (TM) trademark, (R) registered trademark,
-- em dash, ... ellipsis, -> right arrow, <- left arrow, => right
double arrow, <= left double arrow.

You can also include arbitrary entity references in the AsciiDoc
source. Examples:

  &#x278a; &#182;

renders:

&#x278a; &#182;

To render a replacement literally escape it with a leading back-slash.

The <<X7,Configuration Files>> section explains how to configure your
own replacements.

Special Words
~~~~~~~~~~~~~
Words defined in `[specialwords]` configuration file sections are
automatically marked up without having to be explicitly notated.

The <<X7,Configuration Files>> section explains how to add and replace
special words.


[[X17]]
Titles
------
Document and section titles can be in either of two formats:

Two line titles
~~~~~~~~~~~~~~~
A two line title consists of a title line, starting hard against the
left margin, and an underline. Section underlines consist a repeated
character pairs spanning the width of the preceding title (give or
take up to two characters):

The default title underlines for each of the document levels are:


  Level 0 (top level):     ======================
  Level 1:                 ----------------------
  Level 2:                 ~~~~~~~~~~~~~~~~~~~~~~
  Level 3:                 ^^^^^^^^^^^^^^^^^^^^^^
  Level 4 (bottom level):  ++++++++++++++++++++++

Examples:

  Level One Section Title
  -----------------------

  Level 2 Subsection Title
  ~~~~~~~~~~~~~~~~~~~~~~~~

[[X46]]
One line titles
~~~~~~~~~~~~~~~
One line titles consist of a single line delimited on either side by
one or more equals characters (the number of equals characters
corresponds to the section level minus one).  Here are some examples:

  = Document Title (level 0) =
  == Section title (level 1) ==
  === Section title (level 2) ===
  ==== Section title (level 3) ====
  ===== Section title (level 4) =====

[NOTE]
=====================================================================
- One or more spaces must fall between the title and the delimiters.
- The trailing title delimiter is optional.
- The one-line title syntax can be changed by editing the
  configuration file `[titles]` section `sect0`...`sect4` entries.
=====================================================================

Floating titles
~~~~~~~~~~~~~~~
Setting the title's first positional attribute or 'style' attribute to
'float' generates a free-floating title. A free-floating title is
rendered just like a normal section title but is not formally
associated with a text body and is not part of the regular section
hierarchy so the normal ordering rules do not apply. Floating titles
can also be used in contexts where section titles are illegal: for
example sidebar and admonition blocks.  Example:

  [float]
  The second day
  ~~~~~~~~~~~~~~

Floating titles do note appear in a document's table of contents.


[[X42]]
Block Titles
------------
A 'BlockTitle' element is a single line beginning with a period
followed by the title text. A BlockTitle is applied to the immediately
following Paragraph, DelimitedBlock, List, Table or BlockMacro. For
example:

........................
.Notes
- Note 1.
- Note 2.
........................

is rendered as:

.Notes
- Note 1.
- Note 2.


[[X41]]
BlockId Element
---------------
A 'BlockId' is a single line block element containing a unique
identifier enclosed in double square brackets. It is used to assign an
identifier to the ensuing block element for use by referring links.
For example:

  [[chapter-titles]]
  Chapter titles can be ...

The preceding example identifies the following paragraph so it can be
linked from other location, for example with
`<<chapter-titles,chapter titles>>`.

'BlockId' elements can be applied to Title, Paragraph, List,
DelimitedBlock, Table and BlockMacro elements.  The BlockId element
sets the `{id}` attribute for substitution in the subsequent block's
markup template. If a second argument is supplied it sets the
`{reftext}` attribute which is used to set the DocBook `xreflabel`
attribute.

The 'BlockId' element has the same syntax and serves a similar
function to the <<X30,anchor inline macro>>.

[[X79]]
AttributeList Element
---------------------
An 'AttributeList' block element is an <<X21,attribute list>> on a
line by itself:

- 'AttributeList' attributes are only applied to the immediately
  following block element -- the attributes are available for markup
  template substitution.
- A block element can be preceded by multiple 'AttributeList'
  elements.
- Often the first attribute in the list is used to specify the
  following element's <<X23,style>>.

Attribute value substitution
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
By default only attribute references are substituted within attribute
values, this is because not all attributes are destined to be marked
up and rendered as text (for example the table 'cols' attribute). To
perform normal inline text substitutions (special characters, quotes,
macros, replacements) on an attribute value you need to enclose it in
single quotes. In the following quote block the second attribute value
in the AttributeList is quoted to ensure the 'http' macro is expanded
to a hyperlink.

---------------------------------------------------------------------
[quote,'http://en.wikipedia.org/wiki/Samuel_Johnson[Samuel Johnson]']
_____________________________________________________________________
Sir, a woman's preaching is like a dog's walking on his hind legs. It
is not done well; but you are surprised to find it done at all.
_____________________________________________________________________
---------------------------------------------------------------------

Common attributes
~~~~~~~~~~~~~~~~~
Most block elements support the following attributes:

[cols="1e,1,5a",frame="topbot",options="header"]
|====================================================================
|Name |Backends |Description

|id |html4, xhtml11, docbook |
Unique identifier typically serve as link targets.
Can also be set by the 'BlockId' element.

|role |html4, xhtml11, docbook |
Role contains a string used to classify or subclassify an element:

- Adds 'role' attribute to DocBook block elements.
- Adds 'role' attribute to DocBook and HTML <<X51,quoted inline
  elements>>.

|reftext |docbook |
'reftext' is used to set the DocBook 'xreflabel' attribute.
Can also be set by the 'BlockId' element.

|====================================================================


Paragraphs
----------
Paragraphs are blocks of text terminated by a blank line, the end of
file, or the start of a DelimitedBlock.  Paragraph markup is specified
by configuration file `[paradef*]` sections.

Normal paragraphs consist of one or more non-blank lines of text. The
first line must start hard against the left margin (no intervening
white space). The default processing expectation is that of a normal
paragraph of text. 'literal' and 'verse' paragraph styles are
available (in addition to the 'default' paragraph style).

[[X85]]
literal paragraph style
~~~~~~~~~~~~~~~~~~~~~~~~
Literal paragraphs are rendered verbatim in a monospaced font without
any distinguishing background or border.  By default there is no text
formatting or substitutions within Literal paragraphs apart from
Special Characters and Callouts. For example:

---------------------------------------------------------------------
[literal]
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.
---------------------------------------------------------------------

Renders:

[literal]
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.

verse paragraph style
~~~~~~~~~~~~~~~~~~~~~
The 'verse' paragraph <<X23,style>> preserves line boundaries and is
useful for lyrics and poems.  For example:

---------------------------------------------------------------------
[verse]
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.
---------------------------------------------------------------------

Renders:

[verse]
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.


Indented paragraphs
~~~~~~~~~~~~~~~~~~~
Indented paragraphs (the first line indented by one or more space or
tab characters) are rendered using the <<X85,literal paragraph
style>>.  For example:

---------------------------------------------------------------------
  Consul *necessitatibus* per id,
  consetetur, eu pro everti postulant
  homero verear ea mea, qui.
---------------------------------------------------------------------

Renders:

  Consul *necessitatibus* per id,
  consetetur, eu pro everti postulant
  homero verear ea mea, qui.

NOTE: Because <<X64,lists>> can be indented it's possible for your
indented paragraph to be misinterpreted as a list -- in situations
like this apply the 'literal' style to a normal paragraph.

[[X28]]
Admonition Paragraphs
~~~~~~~~~~~~~~~~~~~~~
'Tip', 'Note', 'Important', 'Warning' and 'Caution' paragraph
definitions support the corresponding DocBook admonishment elements --
just write a normal paragraph but place `NOTE:`, `TIP:`, `IMPORTANT:`,
`WARNING:` or `CAUTION:` as the first word of the paragraph. For
example:

  NOTE: This is an example note.

or the alternative syntax:

  [NOTE]
  This is an example note.

Renders:

NOTE: This is an example note.

TIP: If your admonition is more than a single paragraph use an
<<X22,admonition block>> instead.

[[X47]]
Admonition Icons and Captions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
NOTE: Admonition customization with `icons`, `iconsdir`, `icon` and
`caption` attributes does not apply when generating DocBook output. If
you are going the DocBook route then the <<X43,a2x(1)>> `--no-icons`
and `--icons-dir` options can be used to set the appropriate XSL
Stylesheets parameters.

By default the asciidoc(1) `xhtml11` and `html4` backends generate
text captions instead of icon image links. To generate links to icon
images define the <<X45,`icons`>> attribute, for example using the `-a
icons` command-line option.

The <<X44,`iconsdir`>> attribute sets the location of linked icon
images.

You can override the default icon image using the `icon` attribute to
specify the path of the linked image. For example:

  [icon="./images/icons/wink.png"]
  NOTE: What lovely war.

Use the `caption` attribute to customize the admonition captions (not
applicable to `docbook` backend). The following example suppresses the
icon image and customizes the caption of a NOTE admonition (undefining
the `icons` attribute with `icons=None` is only necessary if
<<X45,admonition icons>> have been enabled):

  [icons=None, caption="My Special Note"]
  NOTE: This is my special note.

This subsection also applies to <<X22,Admonition Blocks>>.


Delimited Blocks
----------------
Delimited blocks are blocks of text enveloped by leading and trailing
delimiter lines (normally a series of four or more repeated
characters). The behavior of Delimited Blocks is specified by entries
in configuration file `[blockdef*]` sections.

Predefined Delimited Blocks
~~~~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc ships with a number of predefined DelimitedBlocks (see the
`asciidoc.conf` configuration file in the asciidoc(1) program
directory):

Predefined delimited block underlines:

  CommentBlock:     //////////////////////////
  PassthroughBlock: ++++++++++++++++++++++++++
  ListingBlock:     --------------------------
  LiteralBlock:     ..........................
  SidebarBlock:     **************************
  QuoteBlock:       __________________________
  ExampleBlock:     ==========================
  OpenBlock:        --

The <<X56,code>>, <<X57,source>> and <<X58,music>> filter blocks are
detailed in the <<X59,Filters>> section.

.Default DelimitedBlock substitutions
[cols="2e,7*^",frame="topbot",options="header,autowidth"]
|=====================================================
| |Attributes |Callouts |Macros | Quotes |Replacements
|Special chars |Special words

|PassthroughBlock |Yes |No  |Yes |No  |No  |No  |No
|ListingBlock     |No  |Yes |No  |No  |No  |Yes |No
|LiteralBlock     |No  |Yes |No  |No  |No  |Yes |No
|SidebarBlock     |Yes |No  |Yes |Yes |Yes |Yes |Yes
|QuoteBlock       |Yes |No  |Yes |Yes |Yes |Yes |Yes
|ExampleBlock     |Yes |No  |Yes |Yes |Yes |Yes |Yes
|OpenBlock        |Yes |No  |Yes |Yes |Yes |Yes |Yes
|=====================================================

Listing Blocks
~~~~~~~~~~~~~~
'ListingBlocks' are rendered verbatim in a monospaced font, they
retain line and whitespace formatting and are often distinguished by a
background or border. There is no text formatting or substitutions
within Listing blocks apart from Special Characters and Callouts.
Listing blocks are often used for computer output and file listings.

Here's an example:

[listing]
......................................
--------------------------------------
#include <stdio.h>

int main() {
   printf("Hello World!\n");
   exit(0);
}
--------------------------------------
......................................

Which will be rendered like:

--------------------------------------
#include <stdio.h>

int main() {
    printf("Hello World!\n");
    exit(0);
}
--------------------------------------

By convention <<X59,filter blocks>> use the listing block syntax and
are implemented as listing block styles.

[[X65]]
Literal Blocks
~~~~~~~~~~~~~~
'LiteralBlocks' behave just like LiteralParagraphs except you don't
have to indent the contents.

If the 'listing' style is applied to a LiteralBlock it will be
rendered as a ListingBlock (this is handy if you have a listing
containing a ListingBlock).

---------------------------------------------------------------------
...................................
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.
...................................
---------------------------------------------------------------------

Renders:
...................................
Consul *necessitatibus* per id,
consetetur, eu pro everti postulant
homero verear ea mea, qui.
...................................

Sidebar Blocks
~~~~~~~~~~~~~~
A sidebar is a short piece of text presented outside the narrative
flow of the main text. The sidebar is normally presented inside a
bordered box to set it apart from the main text.

The sidebar body is treated like a normal section body.

Here's an example:

---------------------------------------------------------------------
.An Example Sidebar
************************************************
Any AsciiDoc SectionBody element (apart from
SidebarBlocks) can be placed inside a sidebar.
************************************************
---------------------------------------------------------------------

Which will be rendered like:

.An Example Sidebar
************************************************
Any AsciiDoc SectionBody element (apart from
SidebarBlocks) can be placed inside a sidebar.
************************************************

Apply the 'abstract' style to generate an abstract, for example:

---------------------------------------------------------------------
[abstract]
************************************************
In this paper we will attempt to...
************************************************
---------------------------------------------------------------------

[[X26]]
Comment Blocks
~~~~~~~~~~~~~~
The contents of CommentBlocks are not processed; they are useful for
annotations and for excluding new or outdated content that you don't
want displayed. CommentBlocks are never written to output files.
Example:

---------------------------------------------------------------------
//////////////////////////////////////////
CommentBlock contents are not processed by
asciidoc(1).
//////////////////////////////////////////
---------------------------------------------------------------------

See also <<X25,Comment Lines>>.

NOTE: System macros are executed inside comment blocks.

[[X76]]
Passthrough Blocks
~~~~~~~~~~~~~~~~~~
By default the block contents is subject to attribute and macro
substitution, no other markup is generated.  PassthroughBlock content
will often be backend specific. Here's an example:

---------------------------------------------------------------------
++++++++++++++++++++++++++++++++++++++
<table border="1"><tr>
  <td>Cell 1</td>
  <td>Cell 2</td>
</tr></table>
++++++++++++++++++++++++++++++++++++++
---------------------------------------------------------------------

Use and explicit 'subs' attribute to control substitution.  The
following styles can be applied to passthrough blocks:

pass::
  By default no substitutions are performed.

asciimath, latexmath::
  By default no substitutions are performed, the contents are rendered
  as <<X78,mathematical formulas>>.

Quote Blocks
~~~~~~~~~~~~
'QuoteBlocks' are used for quoted passages of text. There are two
styles: 'quote' and 'verse'. The style is set by the first positional
attribute, if no style attribute is specified the 'quote' style.  The
optional 'attribution' and 'citetitle' attributes (positional
attributes 2 and 3) specify the quote's author and source.

The 'quote' style treats the content like a SectionBody, for example:

---------------------------------------------------------------------
[quote, Bertrand Russell, The World of Mathematics (1956)]
____________________________________________________________________
A good notation has subtlety and suggestiveness which at times makes
it almost seem like a live teacher.
____________________________________________________________________
---------------------------------------------------------------------

Which is rendered as:

[quote, Bertrand Russell, The World of Mathematics (1956)]
____________________________________________________________________
A good notation has subtlety and suggestiveness which at times makes
it almost seem like a live teacher.
____________________________________________________________________

The 'verse' style
retains the content's line breaks, for example:

---------------------------------------------------------------------
[verse, William Blake, from Auguries of Innocence]
__________________________________________________
To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.
__________________________________________________
---------------------------------------------------------------------

Which is rendered as:

[verse, William Blake, from Auguries of Innocence]
__________________________________________________
To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.
__________________________________________________

[[X48]]
Example Blocks
~~~~~~~~~~~~~~
'ExampleBlocks' encapsulate the DocBook Example element and are used
for, well, examples.  Example blocks can be titled by preceding them
with a 'BlockTitle'.  DocBook toolchains normally number examples and
generate a 'List of Examples' backmatter section.

Example blocks are delimited by lines of equals characters and you can
put any block elements apart from Titles, BlockTitles and Sidebars)
inside an example block. For example:

---------------------------------------------------------------------
.An example
=====================================================================
Qui in magna commodo, est labitur dolorum an. Est ne magna primis
adolescens.
=====================================================================
---------------------------------------------------------------------

Renders:

.An example
=====================================================================
Qui in magna commodo, est labitur dolorum an. Est ne magna primis
adolescens.
=====================================================================

A title prefix that can be inserted with the `caption` attribute
(`xhtml11` and `html4` backends). For example:

---------------------------------------------------------------------
[caption="Example 1: "]
.An example with a custom caption
=====================================================================
Qui in magna commodo, est labitur dolorum an. Est ne magna primis
adolescens.
=====================================================================
---------------------------------------------------------------------

[[X22]]
Admonition Blocks
~~~~~~~~~~~~~~~~~
The 'ExampleBlock' definition includes a set of admonition
<<X23,styles>> (NOTE, TIP, IMPORTANT, WARNING, CAUTION) for generating
admonition blocks (admonitions containing more than just a
<<X28,simple paragraph>>).  Just precede the ExampleBlock with an
attribute list containing the admonition style name. For example:

---------------------------------------------------------------------
[NOTE]
.A NOTE block
=====================================================================
Qui in magna commodo, est labitur dolorum an. Est ne magna primis
adolescens.

. Fusce euismod commodo velit.
. Vivamus fringilla mi eu lacus.
  .. Fusce euismod commodo velit.
  .. Vivamus fringilla mi eu lacus.
. Donec eget arcu bibendum
  nunc consequat lobortis.
=====================================================================
---------------------------------------------------------------------

Renders:

[NOTE]
.A NOTE block
=====================================================================
Qui in magna commodo, est labitur dolorum an. Est ne magna primis
adolescens.

. Fusce euismod commodo velit.
. Vivamus fringilla mi eu lacus.
  .. Fusce euismod commodo velit.
  .. Vivamus fringilla mi eu lacus.
. Donec eget arcu bibendum
  nunc consequat lobortis.
=====================================================================

See also <<X47,Admonition Icons and Captions>>.

[[X29]]
Open Blocks
~~~~~~~~~~~
An 'OpenBlock' renders the block contents without any opening or
closing tags. The open block start and end delimiter is a single line
containing two dashes. Enclosed elements are rendered just as they
would inside a section body. Open blocks are used for <<X15,list item
continuation>>.


[[X64]]
Lists
-----
.List types
- Bulleted lists. Also known as itemized or unordered lists.
- Numbered lists. Also called ordered lists.
- Labeled lists. Sometimes called variable or definition lists.
- Callout lists (a list of callout annotations).

.List behavior
- List item indentation is optional and does not determine nesting,
  indentation does however make the source more readable.
- Another list or a literal paragraph immediately following a list
  item will be implicitly included in the list item; use <<X15, list
  item continuation>> to explicitly append other block elements to a
  list item.
- A comment block or a comment line block macro element will terminate
  a list -- use inline comment lines to put comments inside lists.
- The `listindex` <<X60,intrinsic attribute>> is the current list item
  index (1..). If this attribute is not inside a list then it's value
  is the number of items in the most recently closed list. Useful for
  displaying the number of items in a list.

Bulleted Lists
~~~~~~~~~~~~~~
Bulleted list items start with a single dash or one to five asterisks
followed by some white space then some text. Bulleted list syntaxes
are:

...................
- List item.
* List item.
** List item.
*** List item.
**** List item.
***** List item.
...................

Numbered Lists
~~~~~~~~~~~~~~
List item numbers are explicit or implicit.

.Explicit numbering
List items begin with a number followed by some white space then the
item text. The numbers can be decimal (arabic), roman (upper or lower
case) or alpha (upper or lower case). Decimal and alpha numbers are
terminated with a period, roman numbers are terminated with a closing
parenthesis. The different terminators are necessary to ensure 'i',
'v' and 'x' roman numbers are are distinguishable from 'x', 'v' and
'x' alpha numbers. Examples:

.....................................................................
1.   Arabic (decimal) numbered list item.
a.   Lower case alpha (letter) numbered list item.
F.   Upper case alpha (letter) numbered list item.
iii) Lower case roman numbered list item.
IX)  Upper case roman numbered list item.
.....................................................................

.Implicit numbering
List items begin one to five period characters, followed by some white
space then the item text. Examples:

.....................................................................
. Arabic (decimal) numbered list item.
.. Lower case alpha (letter) numbered list item.
... Lower case roman numbered list item.
.... Upper case alpha (letter) numbered list item.
..... Upper case roman numbered list item.
.....................................................................

You can use the 'style' attribute to specify an alternative numbering
style.  The numbered list style can be one of the following values:
'arabic', 'loweralpha', 'upperalpha', 'lowerroman', 'upperroman'.

Here are some examples of bulleted and numbered lists:

---------------------------------------------------------------------
- Praesent eget purus quis magna eleifend eleifend.
  1. Fusce euismod commodo velit.
    a. Fusce euismod commodo velit.
    b. Vivamus fringilla mi eu lacus.
    c. Donec eget arcu bibendum nunc consequat lobortis.
  2. Vivamus fringilla mi eu lacus.
    i)  Fusce euismod commodo velit.
    ii) Vivamus fringilla mi eu lacus.
  3. Donec eget arcu bibendum nunc consequat lobortis.
  4. Nam fermentum mattis ante.
- Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
  * Fusce euismod commodo velit.
  ** Qui in magna commodo, est labitur dolorum an. Est ne magna primis
     adolescens. Sit munere ponderum dignissim et. Minim luptatum et
     vel.
  ** Vivamus fringilla mi eu lacus.
  * Donec eget arcu bibendum nunc consequat lobortis.
- Nulla porttitor vulputate libero.
  . Fusce euismod commodo velit.
  . Vivamus fringilla mi eu lacus.
[upperroman]
    .. Fusce euismod commodo velit.
    .. Vivamus fringilla mi eu lacus.
  . Donec eget arcu bibendum nunc consequat lobortis.
---------------------------------------------------------------------

Which render as:

- Praesent eget purus quis magna eleifend eleifend.
  1. Fusce euismod commodo velit.
    a. Fusce euismod commodo velit.
    b. Vivamus fringilla mi eu lacus.
    c. Donec eget arcu bibendum nunc consequat lobortis.
  2. Vivamus fringilla mi eu lacus.
    i)  Fusce euismod commodo velit.
    ii) Vivamus fringilla mi eu lacus.
  3. Donec eget arcu bibendum nunc consequat lobortis.
  4. Nam fermentum mattis ante.
- Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
  * Fusce euismod commodo velit.
  ** Qui in magna commodo, est labitur dolorum an. Est ne magna primis
     adolescens. Sit munere ponderum dignissim et. Minim luptatum et
     vel.
  ** Vivamus fringilla mi eu lacus.
  * Donec eget arcu bibendum nunc consequat lobortis.
- Nulla porttitor vulputate libero.
  . Fusce euismod commodo velit.
  . Vivamus fringilla mi eu lacus.
[upperroman]
    .. Fusce euismod commodo velit.
    .. Vivamus fringilla mi eu lacus.
  . Donec eget arcu bibendum nunc consequat lobortis.

A predefined 'compact' option is available to bulleted and numbered
lists -- this translates to the DocBook 'spacing="compact"' lists
attribute which may or may not be processed by the DocBook toolchain.
Example:

  [options="compact"]
  - Compact list item.
  - Another compact list item.

TIP: To apply the 'compact' option globally define a document-wide
'compact-option' attribute, e.g. using the `-a compact-option`
command-line option.

Labeled Lists
~~~~~~~~~~~~~
Labeled list items consist of one or more text labels followed the
text of the list item.

An item label begins a line with an alphanumeric character hard
against the left margin and ends with two, three or four colons or two
semi-colons. A list item can have multiple labels, one per line.

The list item text consists of one or more lines of text starting
after the last label (either on the same line or a new line) and can
be followed by nested List or ListParagraph elements. Item text can be
optionally indented.

Here are some examples:

---------------------------------------------------------------------
In::
Lorem::
  Fusce euismod commodo velit.

  Fusce euismod commodo velit.

Ipsum:: Vivamus fringilla mi eu lacus.
  * Vivamus fringilla mi eu lacus.
  * Donec eget arcu bibendum nunc consequat lobortis.
Dolor::
  Donec eget arcu bibendum nunc consequat lobortis.
  Suspendisse;;
    A massa id sem aliquam auctor.
  Morbi;;
    Pretium nulla vel lorem.
  In;;
    Dictum mauris in urna.
    Vivamus::: Fringilla mi eu lacus.
    Donec:::   Eget arcu bibendum nunc consequat lobortis.
---------------------------------------------------------------------

Which render as:

In::
Lorem::
  Fusce euismod commodo velit.

  Fusce euismod commodo velit.

Ipsum:: Vivamus fringilla mi eu lacus.
  * Vivamus fringilla mi eu lacus.
  * Donec eget arcu bibendum nunc consequat lobortis.
Dolor::
  Donec eget arcu bibendum nunc consequat lobortis.
  Suspendisse;;
    A massa id sem aliquam auctor.
  Morbi;;
    Pretium nulla vel lorem.
  In;;
    Dictum mauris in urna.
    Vivamus::: Fringilla mi eu lacus.
    Donec:::   Eget arcu bibendum nunc consequat lobortis.

Horizontal labeled list style
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The 'horizontal' labeled list style places the list text side-by-side
with the label instead of under the label. Here is an example:

---------------------------------------------------------------------
[horizontal]
*Lorem*:: Fusce euismod commodo velit.  Qui in magna commodo, est
labitur dolorum an. Est ne magna primis adolescens.

  Fusce euismod commodo velit.

*Ipsum*:: Vivamus fringilla mi eu lacus.
- Vivamus fringilla mi eu lacus.
- Donec eget arcu bibendum nunc consequat lobortis.

*Dolor*::
  - Vivamus fringilla mi eu lacus.
  - Donec eget arcu bibendum nunc consequat lobortis.

---------------------------------------------------------------------

Which render as:

[horizontal]
*Lorem*:: Fusce euismod commodo velit.  Qui in magna commodo, est
labitur dolorum an. Est ne magna primis adolescens.

  Fusce euismod commodo velit.

*Ipsum*:: Vivamus fringilla mi eu lacus.
- Vivamus fringilla mi eu lacus.
- Donec eget arcu bibendum nunc consequat lobortis.

*Dolor*::
  - Vivamus fringilla mi eu lacus.
  - Donec eget arcu bibendum nunc consequat lobortis.

[NOTE]
=====================================================================
- Current PDF toolchains do not make a good job of determining
  the relative column widths for horizontal labeled lists.
- If you are generating DocBook markup then horizontal labeled lists
  should not be nested because the 'DocBook XML V4.2' DTD does not
  permit nested informal tables (although <<X13,DocBook XSL
  Stylesheets>> and <<X31,dblatex>> process them correctly).
- The label width can be set as a percentage of the total width by
  setting the 'width' attribute e.g. `width="10%"`
=====================================================================

Question and Answer Lists
~~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc comes pre-configured with a 'qanda' style labeled list for generating
DocBook question and answer (Q&A) lists. Example:

---------------------------------------------------------------------
[qanda]
Question one::
        Answer one.
Question two::
        Answer two.
---------------------------------------------------------------------

Renders:

[qanda]
Question one::
        Answer one.
Question two::
        Answer two.

Glossary Lists
~~~~~~~~~~~~~~
AsciiDoc comes pre-configured with a 'glossary' style labeled list for
generating DocBook glossary lists. Example:

---------------------------------------------------------------------
[glossary]
A glossary term::
    The corresponding definition.
A second glossary term::
    The corresponding definition.
---------------------------------------------------------------------

For working examples see the `article.txt` and `book.txt` documents in
the AsciiDoc `./doc` distribution directory.

NOTE: To generate valid DocBook output glossary lists must be located
in a section that uses the 'glossary' <<X93,section markup template>>.

Bibliography Lists
~~~~~~~~~~~~~~~~~~
AsciiDoc comes with a predefined 'bibliography' bulleted list style
generating DocBook bibliography entries. Example:

---------------------------------------------------------------------
[bibliography]
- [[[taoup]]] Eric Steven Raymond. 'The Art of UNIX
  Programming'. Addison-Wesley. ISBN 0-13-142901-9.
- [[[walsh-muellner]]] Norman Walsh & Leonard Muellner.
  'DocBook - The Definitive Guide'. O'Reilly & Associates.
  1999. ISBN 1-56592-580-7.
---------------------------------------------------------------------

The `[[[<reference>]]]` syntax is a bibliography entry anchor, it
generates an anchor named `<reference>` and additionally displays
`[<reference>]` at the anchor position. For example `[\[[taoup]]]`
generates an anchor named `taoup` that displays `[taoup]` at the
anchor position. Cite the reference from elsewhere your document using
`<<taoup>>`, this displays a hyperlink (`[taoup]`) to the
corresponding bibliography entry anchor.

For working examples see the `article.txt` and `book.txt` documents in
the AsciiDoc `./doc` distribution directory.

NOTE: To generate valid DocBook output bibliography lists must be
located in a bibliography section.

[[X15]]
List Item Continuation
~~~~~~~~~~~~~~~~~~~~~~
Another list or a literal paragraph immediately following a list item
is implicitly appended to the list item; to append other block
elements to a list item you need to explicitly join them to the list
item with a 'list continuation' (a separator line containing a single
plus character). Multiple block elements can be appended to a list
item using list continuations (provided they are legal list item
children in the backend markup).

Here are some examples of list item continuations: list item one
contains multiple continuations; list item two is continued with an
<<X29,OpenBlock>> containing multiple elements:

---------------------------------------------------------------------
1. List item one.
+
List item one continued with a second paragraph followed by an
Indented block.
+
.................
$ ls *.sh
$ mv *.sh ~/tmp
.................
+
List item continued with a third paragraph.

2. List item two continued with an open block.
+
--
This paragraph is part of the preceding list item.

a. This list is nested and does not require explicit item continuation.
+
This paragraph is part of the preceding list item.

b. List item b.

This paragraph belongs to item two of the outer list.
--
---------------------------------------------------------------------

Renders:

1. List item one.
+
List item one continued with a second paragraph followed by an
Indented block.
+
.................
$ ls *.sh
$ mv *.sh ~/tmp
.................
+
List item continued with a third paragraph.

2. List item two continued with an open block.
+
--
This paragraph is part of the preceding list item.

a. This list is nested and does not require explicit item continuation.
+
This paragraph is part of the preceding list item.

b. List item b.

This paragraph belongs to item two of the outer list.
--


[[X92]]
Footnotes
---------
The shipped AsciiDoc configuration includes three footnote inline
macros:

`footnote:[<text>]`::
  Generates a footnote with text `<text>`.

`footnoteref:[<id>,<text>]`::
  Generates a footnote with a reference ID `<id>` and text `<text>`.

`footnoteref:[<id>]`::
  Generates a reference to the footnote with ID `<id>`.

The footnote text can span multiple lines.

The 'xhtml11' backend renders footnotes dynamically using JavaScript;
'html4' outputs do not use JavaScript and leave the footnotes inline;
'docbook' footnotes are processed by the downstream DocBook toolchain.

Example footnotes:

  A footnote footnote:[An example footnote.];
  a second footnote with a reference ID footnoteref:[note2,Second footnote.];
  finally a reference to the second footnote footnoteref:[note2].

Renders:

A footnote footnote:[An example footnote.];
a second footnote with a reference ID footnoteref:[note2,Second footnote.];
finally a reference to the second footnote footnoteref:[note2].


Indexes
-------
The shipped AsciiDoc configuration includes the inline macros for
generating document index entries.

`indexterm:[<primary>,<secondary>,<tertiary>]`::
`(((<primary>,<secondary>,<tertiary>)))`::
    This inline macro generates an index term (the <secondary> and
    <tertiary> attributes are optional). For example
    `indexterm:[Tigers,Big cats]` (or, using the alternative syntax
    `(((Tigers,Big cats)))`.  Index terms that have secondary and
    tertiary entries also generate separate index terms for the
    secondary and tertiary entries. The index terms appear in the
    index, not the primary text flow.

`indexterm2:[<primary>]`::
`((<primary>))`::
    This inline macro generates an index term that appears in both the
    index and the primary text flow.  The `<primary>` should not be
    padded to the left or right with white space characters.

For working examples see the `article.txt` and `book.txt` documents in
the AsciiDoc `./doc` distribution directory.

NOTE: Index entries only really make sense if you are generating
DocBook markup -- DocBook conversion programs automatically generate
an index at the point an 'Index' section appears in source document.


Callouts
--------
Callouts are a mechanism for annotating verbatim text (source code,
computer output and user input for example). Callout markers are
placed inside the annotated text while the actual annotations are
presented in a callout list after the annotated text. Here's an
example:

---------------------------------------------------------------------
 .MS-DOS directory listing
 -----------------------------------------------------
 10/17/97   9:04         <DIR>    bin
 10/16/97  14:11         <DIR>    DOS            \<1>
 10/16/97  14:40         <DIR>    Program Files
 10/16/97  14:46         <DIR>    TEMP
 10/17/97   9:04         <DIR>    tmp
 10/16/97  14:37         <DIR>    WINNT
 10/16/97  14:25             119  AUTOEXEC.BAT   \<2>
  2/13/94   6:21          54,619  COMMAND.COM    \<2>
 10/16/97  14:25             115  CONFIG.SYS     \<2>
 11/16/97  17:17      61,865,984  pagefile.sys
  2/13/94   6:21           9,349  WINA20.386     \<3>
 -----------------------------------------------------

 \<1> This directory holds MS-DOS.
 \<2> System startup code for DOS.
 \<3> Some sort of Windows 3.1 hack.
---------------------------------------------------------------------

Which renders:

.MS-DOS directory listing
-----------------------------------------------------
10/17/97   9:04         <DIR>    bin
10/16/97  14:11         <DIR>    DOS            <1>
10/16/97  14:40         <DIR>    Program Files
10/16/97  14:46         <DIR>    TEMP
10/17/97   9:04         <DIR>    tmp
10/16/97  14:37         <DIR>    WINNT
10/16/97  14:25             119  AUTOEXEC.BAT   <2>
 2/13/94   6:21          54,619  COMMAND.COM    <2>
10/16/97  14:25             115  CONFIG.SYS     <2>
11/16/97  17:17      61,865,984  pagefile.sys
 2/13/94   6:21           9,349  WINA20.386     <3>
-----------------------------------------------------

<1> This directory holds MS-DOS.
<2> System startup code for DOS.
<3> Some sort of Windows 3.1 hack.

.Explanation
- The callout marks are whole numbers enclosed in angle brackets that
  refer to an item index in the following callout list.
- By default callout marks are confined to LiteralParagraphs,
  LiteralBlocks and ListingBlocks (although this is a configuration
  file option and can be changed).
- Callout list item numbering is fairly relaxed -- list items can
  start with `<n>`, `n>` or `>` where `n` is the optional list item
  number (in the latter case list items starting with a single `>`
  character are implicitly numbered starting at one).
- Callout lists should not be nested -- start list items hard against
  the left margin.
- If you want to present a number inside angle brackets you'll need to
  escape it with a backslash to prevent it being interpreted as a
  callout mark.

NOTE: To include callout icons in PDF files generated by
<<X43,a2x(1)>> you need to use the `--icons` command-line option.

Implementation Notes
~~~~~~~~~~~~~~~~~~~~
Callout marks are generated by the 'callout' inline macro while
callout lists are generated using the 'callout' list definition. The
'callout' macro and 'callout' list are special in that they work
together. The 'callout' inline macro is not enabled by the normal
'macros' substitutions option, instead it has its own 'callouts'
substitution option.

The following attributes are available during inline callout macro
substitution:

`{index}`::
    The callout list item index inside the angle brackets.
`{coid}`::
    An identifier formatted like `CO<listnumber>-<index>` that
    uniquely identifies the callout mark. For example `CO2-4`
    identifies the fourth callout mark in the second set of callout
    marks.

The `{coids}` attribute can be used during callout list item
substitution -- it is a space delimited list of callout IDs that refer
to the explanatory list item.

Including callouts in included code
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You can annotate working code examples with callouts -- just remember
to put the callouts inside source code comments. This example displays
the `test.py` source file (containing a single callout) using the
<<X57,Source Code Highlighter Filter>>:

.AsciiDoc source
---------------------------------------------------------------------
 [source,python]
 -------------------------------------------
 \include::test.py[]
 -------------------------------------------

 \<1> Print statement.
---------------------------------------------------------------------

.Included `test.py` source
---------------------------------------------------------------------
print 'Hello World!'   # \<1>
---------------------------------------------------------------------


Macros
------
Macros are a mechanism for substituting parametrized text into output
documents.

Macros have a 'name', a single 'target' argument and an 'attribute
list'.  The usual syntax is `<name>:<target>[<attrlist>]` (for
inline macros) and `<name>::<target>[<attrlist>]` (for block
macros).  Here are some examples:

  http://www.methods.co.nz/asciidoc/index.html[Asciidoc home page]
  include::chapt1.txt[tabsize=2]
  mailto:srackham@gmail.com[]

.Macro behavior
- `<name>` is the macro name. It can only contain letters, digits or
  dash characters and cannot start with a dash.
- The optional `<target>` cannot contain white space characters.
- `<attrlist>` is a <<X21,list of attributes>> enclosed in square
  brackets.
- `]` characters in attribute lists that are enclosed in `[]` brackets
  must be escaped with a backslash.
- Expansion of non-system macro references can normally be escaped by
  prefixing a backslash character (see the AsciiDoc 'FAQ' for examples
  of exceptions to this rule).
- System macros cannot be escaped.
- Attribute references in block macros are expanded.
- The substitutions performed prior to Inline macro macro expansion
  are determined by the inline context.
- Macros are processed in the order they appear in the configuration
  file(s).
- Calls to inline macros can be nested inside different inline macros
  (an inline macro call cannot contain a nested call to itself).
- In addition to `<name>`, `<target>` and `<attrlist>` the
  `<passtext>` and `<subslist>` named groups are available to
  <<X77,passthrough macros>>. A macro is a passthrough macro if the
  definition includes a `<passtext>` named group.

Inline Macros
~~~~~~~~~~~~~
Inline Macros occur in an inline element context. Predefined Inline
macros include 'URLs', 'image' and 'link' macros.

URLs
^^^^
'http', 'https', 'ftp', 'file', 'mailto' and 'callto' URLs are
rendered using predefined inline macros.

- If you don't need a custom link caption you can enter the 'http',
  'https', 'ftp', 'file' URLs and email addresses without any special
  macro syntax.
- If the `<attrlist>` is empty the URL is displayed.

Here are some examples:

  http://www.methods.co.nz/asciidoc/[The AsciiDoc home page]
  http://www.methods.co.nz/asciidoc/
  mailto:joe.bloggs@foobar.com[email Joe Bloggs]
  joe.bloggs@foobar.com

Which are rendered:

http://www.methods.co.nz/asciidoc/[The AsciiDoc home page]

http://www.methods.co.nz/asciidoc/

mailto:joe.bloggs@foobar.com[email Joe Bloggs]

joe.bloggs@foobar.com

- If the `<target>` necessitates space characters they should be
  replaced by `%20`. For example `large%20image.png`.
- Define an attribute entry if you refer to the same URL more than
  once, this will make your document <<X62,easier to maintain and
  easier to read>>.

Internal Cross References
^^^^^^^^^^^^^^^^^^^^^^^^^
Two AsciiDoc inline macros are provided for creating hypertext links
within an AsciiDoc document. You can use either the standard macro
syntax or the (preferred) alternative.

[[X30]]
anchor
++++++
Used to specify hypertext link targets:

  [[<id>,<xreflabel>]]
  anchor:<id>[<xreflabel>]

The `<id>` is a unique identifier that must begin with a letter. The
optional `<xreflabel>` is the text to be displayed by captionless
'xref' macros that refer to this anchor. The optional `<xreflabel>` is
only really useful when generating DocBook output. Example anchor:

  [[X1]]

You may have noticed that the syntax of this inline element is the
same as that of the <<X41,BlockId block element>>, this is no
coincidence since they are functionally equivalent.

xref
++++
Creates a hypertext link to a document anchor.

  <<<id>,<caption>>>
  xref:<id>[<caption>]

The `<id>` refers to an existing anchor `<id>`. The optional
`<caption>` is the link's displayed text. Example:

  <<X21,attribute lists>>

If `<caption>` is not specified then the displayed text is
auto-generated:

- The AsciiDoc `xhtml11` backend displays the `<id>` enclosed in
  square brackets.
- If DocBook is produced the DocBook toolchain is responsible for the
  displayed text which will normally be the referenced figure, table
  or section title number followed by the element's title text.

Here is an example:

---------------------------------------------------------------------
[[tiger_image]]
.Tyger tyger
image::tiger.png[]

This can be seen in <<tiger_image>>.
---------------------------------------------------------------------

Linking to Local Documents
^^^^^^^^^^^^^^^^^^^^^^^^^^
Hypertext links to files on the local file system are specified using
the 'link' inline macro.

  link:<target>[<caption>]

The 'link' macro generates relative URLs. The link macro `<target>` is
the target file name (relative to the file system location of the
referring document). The optional `<caption>` is the link's displayed
text. If `<caption>` is not specified then `<target>` is displayed.
Example:

  link:downloads/foo.zip[download foo.zip]

You can use the `<filename>#<id>` syntax to refer to an anchor within
a target document but this usually only makes sense when targeting
HTML documents.

Images can serve as hyperlinks using the <<X9,`image` macro>>.

[[X9]]
Images
^^^^^^
Inline images are inserted into the output document using the 'image'
macro. The inline syntax is:

  image:<target>[<attributes>]

The contents of the image file `<target>` is displayed. To display the
image its file format must be supported by the target backend
application. HTML and DocBook applications normally support PNG or JPG
files.

`<target>` file name paths are relative to the location of the
referring document.

[[X55]]
.Image macro attributes
- The optional 'alt' attribute is also the first positional attribute,
  it specifies alternative text which is displayed if the output
  application is unable to display the image file (see also
  http://htmlhelp.com/feature/art3.htm[Use of ALT texts in IMGs]). For
  example:

  image:images/logo.png[Company Logo]

- The optional 'title' attribute provides a title for the image. The
  <<X49,block image macro>> renders the title alongside the image.
  The inline image macro displays the title as a popup ``tooltip'' in
  visual browsers (AsciiDoc HTML outputs only).

- The optional `width` and `height` attributes scale the image size
  and can be used in any combination. The units are pixels.  The
  following example scales the previous example to a height of 32
  pixels:

  image:images/logo.png["Company Logo",height=32]

- The optional `link` attribute is used to link the image to an
  external document. The following example links a screenshot
  thumbnail to a full size version:

  image:screen-thumbnail.png[height=32,link="screen.png"]

- The optional `scaledwidth` attribute is only used in DocBook block
  images (specifically for PDF documents). The following example
  scales the images to 75% of the available print width:

  image::images/logo.png[scaledwidth="75%",alt="Company Logo"]

- The optional `align` attribute is used for horizontal image
  alignment.  Allowed values are `center`, `left` and `right`. For
  example:

  image::images/tiger.png["Tiger image",align="left"]

- The optional `float` attribute floats the image `left` or `right` on
  the page (works with HTML outputs only, has no effect on DocBook
  outputs). `float` and `align` attributes are mutually exclusive.
  Use the `unfloat::[]` block macro to stop floating.

Comment Lines
^^^^^^^^^^^^^
See <<X25,comment block macro>>.

Block Macros
~~~~~~~~~~~~
A Block macro reference must be contained in a single line separated
either side by a blank line or a block delimiter.

Block macros behave just like Inline macros, with the following
differences:

- They occur in a block context.
- The default syntax is `<name>::<target>[<attrlist>]` (two
  colons, not one).
- Markup template section names end in `-blockmacro` instead of
  `-inlinemacro`.

Block Identifier
^^^^^^^^^^^^^^^^
The Block Identifier macro sets the `id` attribute and has the same
syntax as the <<X30,anchor inline macro>> since it performs
essentially the same function -- block templates employ the `id`
attribute as a block link target. For example:

  [[X30]]

This is equivalent to the `[id="X30"]` block attribute list.

[[X49]]
Images
^^^^^^
Formal titled images are inserted into the output document using the
'image' macro. The syntax is:

  image::<target>[<attributes>]

The block `image` macro has the same <<X55,macro attributes>> as it's
<<X9,inline image macro>> counterpart.

Block images can be titled by preceding the 'image' macro with a
'BlockTitle'.  DocBook toolchains normally number examples and
generate a 'List of Figures' backmatter section.

This example:

  .Main circuit board
  image::images/layout.png[J14P main circuit board]

is equivalent to:

  image::images/layout.png["J14P main circuit board",
                            title="Main circuit board"]

A title prefix that can be inserted with the `caption` attribute
(`xhtml11` and `html4` backends). For example:

  .Main circuit board
  [caption="Figure 2: "]
  image::images/layout.png[J14P main circuit board]

[[X66]]
.Embedding images in XHTML documents
*********************************************************************
If you define the `data-uri` attribute then images will be embedded in
XHTML outputs using the
http://en.wikipedia.org/wiki/Data:_URI_scheme[data URI scheme].  You
can use the 'data-uri' attribute with the 'xhtml11' backend to produce
single-file XHTML documents with embedded images and CSS, for example:

  $ asciidoc -a data-uri mydocument.txt

NOTE: All current popular browsers support 'data URIs', although
versions of Internet Explorer prior to version 8 do not support 'data
URIs'.
*********************************************************************

[[X25]]
Comment Lines
^^^^^^^^^^^^^
Single lines starting with two forward slashes hard up against the
left margin are treated as comments. Comment lines do not appear in
the output unless the 'showcomments' attribute is defined.  Comment
lines have been implemented as both block and inline macros so a
comment line can appear as a stand-alone block or within block elements
that support inline macro expansion. Example comment line:

  // This is a comment.

If the 'showcomments' attribute is defined comment lines are written
to the output:

- The normal AsciiDoc inline text formatting is applied to comment
  lines.
- In DocBook the comment lines are enclosed by the 'remark' element
  (which may or may not be rendered by your toolchain).
- The 'showcomments' attribute does not expose <<X26,Comment Blocks>>.
  Comment Blocks are never passed to the output.

System Macros
~~~~~~~~~~~~~
System macros are block macros that perform a predefined task and are
hardwired into the asciidoc(1) program.

- You can escape system macros with a leading backslash character
  (as you can with other macros).
- The syntax and tasks performed by system macros is built into
  asciidoc(1) so they don't appear in configuration files.  You can
  however customize the syntax by adding entries to a configuration
  file `[macros]` section.

[[X63]]
Include Macros
^^^^^^^^^^^^^^
The `include` and `include1`  system macros to include the contents of
a named file into the source document.

The `include` macro includes a file as if it were part of the parent
document -- tabs are expanded and system macros processed. The
contents of `include1` files are not subject to tab expansion or
system macro processing nor are attribute or lower priority
substitutions performed. The `include1` macro's intended use is to
include verbatim embedded CSS or scripts into configuration file
headers.  Example:

------------------------------------
\include::chapter1.txt[tabsize=4]
------------------------------------

.Include macro behavior
- If the included file name is specified with a relative path then the
  path is relative to the location of the referring document.
- Include macros can appear inside configuration files.
- Files included from within 'DelimitedBlocks' are read to completion
  to avoid false end-of-block underline termination.
- Attribute references are expanded inside the include 'target'; if an
  attribute is undefined then the included file is silently skipped.
- The 'tabsize' macro attribute sets the number of space characters to
  be used for tab expansion in the included file (not applicable to
  `include1` macro).
- The 'depth' macro attribute sets the maximum permitted number of
  subsequent nested includes (not applicable to `include1` macro which
  does not process nested includes). Setting 'depth' to '1' disables
  nesting inside the included file. By default, nesting is limited to
  a depth of five.
- Internally the `include1` macro is translated to the `include1`
  system attribute which means it must be evaluated in a region where
  attribute substitution is enabled. To inhibit nested substitution in
  included files it is preferable to use the `include` macro and set
  the attribute `depth=1`.

Conditional Inclusion Macros
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Lines of text in the source document can be selectively included or
excluded from processing based on the existence (or not) of a document
attribute.  There are two conditional inclusion macros; the first
includes document text between the `ifdef` and `endif` macros if a
document attribute is defined:

  ifdef::<attribute>[]
  :
  endif::<attribute>[]

The second includes document text between the `ifndef` and `endif`
macros if the attribute is not defined:

  ifndef::<attribute>[]
  :
  endif::<attribute>[]

`<attribute>` is an attribute name which is optional in the trailing
`endif` macro.

If you only want to process a single line of text then the text can be
put inside the square brackets and the `endif` macro omitted, for
example:

  ifdef::revnumber[Version number 42]

Is equivalent to:

  ifdef::revnumber[]
  Version number 42
  endif::revnumber[]

Take a look at the `*.conf` configuration files in the AsciiDoc
distribution for examples of conditional inclusion macro usage.

.Two types of conditional inclusion
*********************************************************************
Conditional inclusion macros are evaluated when they are read, but
there is another type of conditional inclusion based on attribute
references, the latter being evaluated when the output file is
written.

These examples illustrate the two forms of conditional inclusion. The
only difference between them is that the first is evaluated at program
load time while the second is evaluated when the output is written:

  ifdef::world[]
    Hello World!
  endif::world[]

  {world#}Hello World!

In this example when the `{world#}` conditional attribute reference
is evaluates to a zero length string if `world` is defined; if `world`
is not defined the whole line is dropped.

The subtle difference between the two types of conditional inclusion
has implications for AsciiDoc configuration files: AsciiDoc has to
read the configuration files *before* reading the source document,
this is necessary because the AsciiDoc source syntax is mostly defined
by the configuration files.  This means that any lines of markup
enveloped by conditional inclusion macros will be included or excluded
*before* the attribute entries in the AsciiDoc document header are
read, so setting related attributes in the AsciiDoc source document
header will have no effect.  If you need to control configuration file
markup inclusion with attribute entries in the AsciiDoc source file
header you need to use attribute references to control inclusion
instead of conditional inclusion macros (attribute references are
substituted at the time the output is written rather than at program
startup).
*********************************************************************

Executable system macros
^^^^^^^^^^^^^^^^^^^^^^^^
The 'eval', 'sys' and 'sys2' block macros exhibit the same behavior as
their same named <<X24, system attribute references>>. The difference
is that system macros occur in a block macro context whereas system
attributes are confined to an inline context where attribute
substitution is enabled.

The following example displays a long directory listing inside a
literal block:

  ------------------
  sys::[ls -l *.txt]
  ------------------

NOTE: There are no block macro versions of the 'eval3' and 'sys3'
system attributes.

Template System Macro
^^^^^^^^^^^^^^^^^^^^^
The `template` block macro allows the inclusion of one configuration
file template section within another.  The following example includes
the `[admonitionblock]` section in the `[admonitionparagraph]`
section:

  [admonitionparagraph]
  template::[admonitionblock]

.Template macro behavior
- The `template::[]` macro is useful for factoring configuration file
  markup.
- `template::[]` macros cannot be nested.
- `template::[]` macro expansion is applied to all sections
  after all configuration files have been read.


[[X77]]
Passthrough macros
~~~~~~~~~~~~~~~~~~
Passthrough macros are analogous to <<X76,passthrough blocks>> and are
used to pass text directly to the output. The substitution performed
on the text is determined by the macro definition but can be overridden
by the `<subslist>`.  The usual syntax is
`<name>:<subslist>[<passtext>]` (for inline macros) and
`<name>::<subslist>[<passtext>]` (for block macros).

pass::
  Inline and block. Passes text unmodified apart from explicitly
  specified substitutions). Examples:

  pass:[<q>To be or not to be</q>]
  pass:attributes,quotes[<u>the '{author}'</u>]

asciimath, latexmath::
  Inline and block. Passes text unmodified.  Used for
  <<X78,mathematical formulas>>.

\+++::
  Inline and block. The triple-plus passthrough is functionally
  identical to the 'pass' macro but you don't have to escape `]`
  characters and you can prefix with quoted attributes in the inline
  version. Example:

  Red [red]+++`sum_(i=1)\^n i=(n(n+1))/2`$+++ AsciiMathML formula

$$::
  Inline and block. The double-dollar passthrough is functionally
  identical to the triple-plus passthrough with one exception: special
  characters are escaped. Example:

  $$`[[a,b],[c,d]]((n),(k))`$$

[[X80]]`::
  Text quoted with single backtick characters constitutes an 'inline
  literal' passthrough. The enclosed text is rendered in a monospaced
  font and is only subject to special character substitution.  This
  makes sense since monospace text is usually intended to be rendered
  literally and often contains characters that would otherwise have to
  be escaped. If you need monospaced text containing inline
  substitutions use a <<X81,plus character instead of a backtick>>.

Macro Definitions
~~~~~~~~~~~~~~~~~
Each entry in the configuration `[macros]` section is a macro
definition which can take one of the following forms:

`<pattern>=<name>[<subslist]`::
        Inline macro definition.
`<pattern>=#<name>[<subslist]`::
        Block macro definition.
`<pattern>=+<name>[<subslist]`::
        System macro definition.
`<pattern>`::
        Delete the existing macro with this `<pattern>`.

`<pattern>` is a Python regular expression and `<name>` is the name of
a markup template. If `<name>` is omitted then it is the value of the
regular expression match group named 'name'.  The optional
`[<subslist]` is a comma-separated list of substitution names enclosed
in `[]` brackets, it sets the default substitutions for passthrough
text, if omitted then no passthrough substitutions are performed.

.Pattern named groups
The following named groups can be used in macro `<pattern>` regular
expressions and are available as markup template attributes:

name::
  The macro name.

target::
  The macro target.

attrlist::
  The macro attribute list.

passtext::
  Contents of this group are passed unmodified to the output subject
  only to 'subslist' substitutions.

subslist::
  Processed as a comma-separated list of substitution names for
  'passtext' substitution, overrides the the macro definition
  'subslist'.

.Here's what happens during macro substitution
- Each contextually relevant macro 'pattern' from the `[macros]`
  section is matched against the input source line.
- If a match is found the text to be substituted is loaded from a
  configuration markup template section named like
  `<name>-inlinemacro` or `<name>-blockmacro` (depending on the macro
  type).
- Global and macro attribute list attributes are substituted in the
  macro's markup template.
- The substituted template replaces the macro reference in the output
  document.


Tables
------
The AsciiDoc table syntax looks and behaves like other delimited block
types and supports standard <<X73,block configuration entries>>.
Formatting is easy to read and, just as importantly, easy to enter.

- Cells and columns can be formatted using built-in customizable styles.
- Horizontal and vertical cell alignment can be set on columns and
  cell.
- Horizontal and vertical cell spanning is supported.

.Use tables sparingly
*********************************************************************
When technical users first start creating documents, tables (complete
with column spanning and table nesting) are often considered very
important. The reality is that tables are seldom used, even in
technical documentation.

Try this exercise: thumb through your library of technical books,
you'll be surprised just how seldom tables are actually used, even
less seldom are tables containing block elements (such as paragraphs
or lists) or spanned cells. This is no accident, like figures, tables
are outside the normal document flow -- tables are for consulting not
for reading.

Tables are designed for, and should normally only be used for,
displaying column oriented tabular data.
*********************************************************************

Example tables
~~~~~~~~~~~~~~

.Simple table
[width="15%"]
|=======
|1 |2 |A
|3 |4 |B
|5 |6 |C
|=======

.AsciiDoc source
---------------------------------------------------------------------
[width="15%"]
|=======
|1 |2 |A
|3 |4 |B
|5 |6 |C
|=======
---------------------------------------------------------------------

.Columns formatted with strong, monospaced and emphasis styles
[width="50%",cols=">s,^m,e",frame="topbot",options="header,footer"]
|==========================
|      2+|Columns 2 and 3
|1       |Item 1  |Item 1
|2       |Item 2  |Item 2
|3       |Item 3  |Item 3
|4       |Item 4  |Item 4
|footer 1|footer 2|footer 3
|==========================

.AsciiDoc source
---------------------------------------------------------------------
.An example table
[width="50%",cols=">s,^m,e",frame="topbot",options="header,footer"]
|==========================
|      2+|Columns 2 and 3
|1       |Item 1  |Item 1
|2       |Item 2  |Item 2
|3       |Item 3  |Item 3
|4       |Item 4  |Item 4
|footer 1|footer 2|footer 3
|==========================
---------------------------------------------------------------------

.Horizontal and vertical source data
[width="80%",cols="3,^2,^2,10",options="header"]
|=========================================================
|Date |Duration |Avg HR |Notes

|22-Aug-08 |10:24 | 157 |
Worked out MSHR (max sustainable heart rate) by going hard
for this interval.

|22-Aug-08 |23:03 | 152 |
Back-to-back with previous interval.

|24-Aug-08 |40:00 | 145 |
Moderately hard interspersed with 3x 3min intervals (2min
hard + 1min really hard taking the HR up to 160).

|=========================================================

Short cells can be entered horizontally, longer cells vertically.  The
default behavior is to strip leading and trailing blank lines within a
cell. These characteristics aid readability and data entry.

.AsciiDoc source
---------------------------------------------------------------------
.Windtrainer workouts
[width="80%",cols="3,^2,^2,10",options="header"]
|=========================================================
|Date |Duration |Avg HR |Notes

|22-Aug-08 |10:24 | 157 |
Worked out MSHR (max sustainable heart rate) by going hard
for this interval.

|22-Aug-08 |23:03 | 152 |
Back-to-back with previous interval.

|24-Aug-08 |40:00 | 145 |
Moderately hard interspersed with 3x 3min intervals (2min
hard + 1min really hard taking the HR up to 160).

|=========================================================
---------------------------------------------------------------------

.A table with externally sourced CSV data
[format="csv",cols="^1,4*2",options="header"]
|===================================================
ID,Customer Name,Contact Name,Customer Address,Phone
include::customers.csv[]
|===================================================

.AsciiDoc source
---------------------------------------------------------------------
[format="csv",cols="^1,4*2",options="header"]
|===================================================
ID,Customer Name,Contact Name,Customer Address,Phone
\include::customers.csv[]
|===================================================
---------------------------------------------------------------------


.Cell spans, alignments and styles
[cols="e,m,^,>s",width="25%"]
|============================
|1 >s|2 |3 |4
^|5 2.2+^.^|6 .3+<.>m|7
^|8
|9 2+>|10
|============================

.AsciiDoc source
---------------------------------------------------------------------
[cols="e,m,^,>s",width="25%"]
|============================
|1 >s|2 |3 |4
^|5 2.2+^.^|6 .3+<.>m|7
^|8
|9 2+>|10
|============================
---------------------------------------------------------------------

[[X68]]
Table input data formats
~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc table data can be 'psv', 'dsv' or 'csv' formatted.  The
default table format is 'psv'.

AsciiDoc 'psv' ('Prefix Separated Values') and 'dsv' ('Delimiter
Separated Values') formats are cell oriented -- the table is treated
as a sequence of cells -- there are no explicit row separators.

- 'psv' prefixes each cell with a separator whereas 'dsv' delimits
  cells with a separator, that really the only difference (apart from
  different default separators).
- 'psv' and 'dsv' separators are Python regular expressions.
- The default 'psv' separator contains <<X84, cell specifier>> related
  named regular expression groups.
- The default 'dsv' separator is `:|\n` (a colon or a line break).
- 'psv' and 'dsv' cell separators can be escaped by preceding them
  with a backslash character.

Here are four 'psv' cells (the second item spans two columns; the
last contains an escaped separator):

  |One 2+|Two and three |A \| separator character

'csv'  is the quasi-standard row oriented 'Comma Separated Values
(CSV)' format commonly used to import and export spreadsheet and
database data.

[[X69]]
Table attributes
~~~~~~~~~~~~~~~~
Individual tables are customized by an optional <<X79,AttributeList>>
preceding the table. Specify attributes when you want to change the
default table format:

format::
'psv' (default), 'dsv' or 'csv' (See <<X68, Table Data Formats>>).

separator::
The cell separator. A Python regular expression ('psv' and 'dsv'
formats) or a single character ('csv' format).

frame::
Defines the table border and can take the following values: 'topbot'
(top and bottom), 'all' (all sides), 'none' and 'sides' (left and
right sides). The default value is 'all'.

grid::
Defines which ruler lines are drawn between table rows and columns.
The 'grid' attribute value can be any of the following values: 'none',
'cols', 'rows' and 'all'. The default value is 'all'.

align::
Use the 'align' attribute to horizontally align the table on the
page (works with HTML outputs only, has no effect on DocBook outputs).
The following values are valid: 'left', 'right', and 'center'.

float::
Use the 'float' attribute to float the table 'left' or 'right' on the
page (works with HTML outputs only, has no effect on DocBook outputs).
Floating only makes sense in conjunction with the table 'width'
attribute set to less than 100% (otherwise the table will take up all
the available space).  'float' and 'align' attributes are mutually
exclusive.  Use the `unfloat::[]` block macro to stop floating.

halign::
Use the 'halign' attribute to horizontally align all cells in a table.
The following values are valid: 'left', 'right', and 'center'
(defaults to 'left'). Overridden by <<X70,Column specifiers>>  and
<<X84,Cell specifiers>>.

valign::
Use the 'valign' attribute to vertically align all cells in a table.
The following values are valid: 'top', 'bottom', and 'middle'
(defaults to 'top'). Overridden by <<X70,Column specifiers>>  and
<<X84,Cell specifiers>>.

options::
The 'options' attribute can contain the following comma separated
values: 'header', 'footer'. By default header and footer rows are
omitted.

cols::
The 'cols' attribute is a comma separated list of <<X70,column
specifiers>>. For example `cols="2<p,2*,4p,>"`.

- If 'cols' is present it must specify all columns.
- If the 'cols' attribute is not specified the number of columns is
  calculated as the number of data items in the *first line* of the
  table.
- The degenerate form for the 'cols' attribute is an integer
  specifying the number of columns e.g. `cols=4`.

width::
The 'width' attribute is expressed as a percentage value
('"1%"'...'"99%"'). The width specifies the table width relative to
the available width. HTML backends use this value to set the table
width attribute. It's a bit more complicated with DocBook, see the
<<X89,DocBook table widths>> sidebar.

filter::
The 'filter' attribute defines an external shell command that is
invoked for each cell. The built-in 'asciidoc' table style is
implemented using a filter.

[[X89]]
.DocBook table widths
*********************************************************************
The AsciiDoc docbook backend generates CALS tables. CALS tables do not
support a table width attribute -- table width can only be controlled
using absolute column widths. If the AsciiDoc table width attribute is
specified the docbook backend emits absolute column widths (see
calculated <<X72,markup attributes>> ); if no table width is specified
proportional column widths are used and the table occupies all of the
available width.

Specifying fixed column widths not media independent because different
presentation media have different physical characteristics e.g.
printed paper vs. web browsers.  To get round this limitation 'DocBook
XSL Stylesheets' have implemented
http://www.sagehill.net/docbookxsl/Tables.html#TableWidth[processing
instructions] for setting the table width as a percentage of the
available width. AsciiDoc emits these processing instructions and, to
facilitate their use, uses proportional column widths (by defaulting
the AsciiDoc 'pageunits' attribute to '*'). To generate DocBook tables
with fixed  widths set 'pageunits' to a CALS absolute unit such as
'pt'.
*********************************************************************

[[X70]]
Column Specifiers
~~~~~~~~~~~~~~~~~
Column specifiers define how columns are rendered and appear in the
table <<X69,cols attribute>>.  A column specifier consists of an
optional column multiplier followed by optional alignment, width and
style values and is formatted like:

  [<multiplier>*][<align>][<width>][<style>]

- All components are optional. The multiplier must be first and the
  style last. The order of `<align>` or `<width>` is not important.
- Column `<width>` can be either an integer proportional value (1...)
  or a percentage (1%...100%). The default value is 1. To ensure
  portability across different backends, there is no provision for
  absolute column widths (not to be confused with output column width
  <<X72,markup attributes>> which are available in both percentage and
  absolute units).
- The '<align>' column alignment specifier is formatted like:

  [<horizontal>][.<vertical>]
+
Where `<horizontal>` and `<vertical>` are one of the following
characters: `<`, `^` or `>` which represent `left`, `center` and
`right` horizontal alignment or `top`, `middle` and `bottom` vertical
alignment respectively.

- A `<multiplier>` can be used to specify repeated columns e.g.
  `cols="4*<"` specifies four left-justified columns. Default value 1.
- The `<style>` name specifies a <<X71,table style>> to used to markup
  column cells (you can use the full style names if you wish but the
  first letter is normally sufficient).
- Column specific styles are not applied to 'header' row formatting.

[[X84]]
Cell Specifiers
~~~~~~~~~~~~~~~
Cell specifiers allow individual cells in 'psv' formatted tables to be
spanned, multiplied, aligned and styled.  Cell specifiers prefix 'psv'
`|` delimiters and are formatted like:

  [<span>*|+][<align>][<style>]

- '<span>' specifies horizontal and vertical cell spans ('+' operator) or
  the number of times the cell is replicated ('*' operator). '<span>'
  is formatted like:

  [<colspan>][.<rowspan>]
+
Where `<colspan>` and `<rowspan>` are integers specifying the number of
columns and rows to span.

- `<align>` specifies horizontal and vertical cell alignment an is the
  same as in <<X70,column specifiers>>.
- A `<style>` value is the first letter of <<X71,table style>> name.

For example, the following 'psv' formatted cell will span two columns
and the text will be centered and emphasized:

  `2+^e| Cell text`

[[X71]]
Table styles
~~~~~~~~~~~~
Table styles can be applied to the entire table (by setting the
'style' attribute in the table's attribute list) or on a per column
basis (by specifying the style in the table's <<X69,cols attribute>>).
Tables come with the following predefined styles:

default::
The default style: AsciiDoc inline text formatting; blank lines are
treated as paragraph breaks.

emphasis::
Like default but all text is emphasised.

monospaced::
Like default but all text is in a monospaced font.

strong::
Like default but all text is bold.

header::
Apply the same style as the table header. Normally used to create a
vertical header in the first column.

asciidoc::
With this style table cells can contain any of the AsciiDoc elements
that are allowed inside document sections. This style runs asciidoc(1)
as a filter to process cell contents. See also <<X83,Docbook table
limitations>>.

literal::
No text formatting; monospaced font; all line breaks are retained
(like AsciiDoc 'LiteralBlock').

verse::
Text formatting; all line breaks are retained (c.f. AsciiDoc delimited
block 'verse' style).

[[X72]]
Markup attributes
~~~~~~~~~~~~~~~~~
AsciiDoc makes a number of attributes available to table markup
templates and tags. Both absolute and percentage width values are
available. Column specific attributes are available when substituting
the 'colspec' cell data tags.

pageunits::
DocBook backend only. Specifies table column absolute width units.
Defaults to '*'.

pagewidth::
DocBook backend only. The nominal output page width in 'pageunit'
units. Used to calculate CALS tables absolute column and table
widths. Defaults to '425'.

tableabswidth::
Integer value calculated from 'width' and 'pagewidth' attributes.
In 'pageunit' units.

tablepcwidth::
Table width expressed as a percentage of the available width. Integer
value (0..100).

colabswidth::
Integer value calculated from 'cols' column width, 'width' and
'pagewidth' attributes.  In 'pageunit' units.

colpcwidth::
Column width expressed as a percentage of the table width. Integer
value (0..100).

colcount::
Total number of table columns.

rowcount::
Total number of table rows.

halign::
Horizontal cell content alignment: 'left', 'right' or 'center'.

valign::
Vertical cell content alignment: 'top', 'bottom' or 'middle'.

colnumber, colstart::
The number of the leftmost column occupied by the cell (1...).

colend::
The number of the rightmost column occupied by the cell (1...).

colspan::
Number of columns the cell should span.

rowspan::
Number of rows the cell should span (1...).

morerows::
Number of additional rows the cell should span (0...).

Nested tables
~~~~~~~~~~~~~
An alternative table syntax using a '!' character instead of a '|'
character is provided to allow a single level of table nesting.
Columns containing nested tables must use the 'asciidoc' style. An
example can be found in `./examples/website/newtables.txt`.

[[X83]]
DocBook table limitations
~~~~~~~~~~~~~~~~~~~~~~~~~
Fully implementing tables is not trivial, some DocBook toolchains do
better than others.  AsciiDoc HTML table outputs are rendered
correctly in all the popular browsers -- if your DocBook generated
tables don't look right compare them with the output generated by the
AsciiDoc 'xhtml11' backend or try a different DocBook toolchain.  Here
is a list of things to be aware of:

- Although nested tables are not legal in DocBook 4 the FOP and
  dblatex toolchains will process them correctly.  If you use `a2x(1)`
  you will need to include the `--no-xmllint` option to suppress
  DocBook validation errors.
+
NOTE: Technically you can nest DocBook 4 tables one level using the
'entrytbl' element, but not all toolchains process 'entrytbl'.

- DocBook only allows a subset of block elements inside table cells so
  not all AsciiDoc elements produce valid DocBook inside table cells.
  If you get validation errors running `a2x(1)` try the `--no-xmllint`
  option, toolchains will often process nested block elements such as
  sidebar blocks and floating titles correctly.

- Text formatting in cells using the 'monospaced' table style will
  raise validation errors because the DocBook 'literal' element was
  not designed to support formatted text (using the 'literal' element
  is a kludge on the part of AsciiDoc as there is no easy way to set
  the font style in DocBook.

- Cell alignments are ignored for 'verse', 'literal' or 'asciidoc'
   table styles.


[[X1]]
Manpage Documents
-----------------
Sooner or later, if you program for a UNIX environment, you're going
to have to write a man page.

By observing a couple of additional conventions you can compose
AsciiDoc files that will translate to a DocBook refentry (man page)
document.  The resulting DocBook file can then be translated to the
native roff man page format (or other formats).

For example, the `asciidoc.1.txt` file in the AsciiDoc distribution
`./doc` directory was used to generate both the
`asciidoc.1.css-embedded.html` HTML file the `asciidoc.1` roff
formatted `asciidoc(1)` man page.

.Viewing and printing manpage files
**********************************************************************
Use the `man(1)` command to view the manpage file:

  $ man -l asciidoc.1

To print a high quality man page to a postscript printer:

  $ man -l -Tps asciidoc.1 | lpr

You could also create a PDF version of the man page by converting
PostScript to PDF using `ps2pdf(1)`:

  $ man -l -Tps asciidoc.1 | ps2pdf - asciidoc.1.pdf

The `ps2pdf(1)` command is included in the Ghostscript distribution.
**********************************************************************

To find out more about man pages view the `man(7)` manpage
(`man 7 man` and `man man-pages` commands).


Document Header
~~~~~~~~~~~~~~~
A document Header is mandatory. The title line contains the man page
name followed immediately by the manual section number in brackets,
for example 'ASCIIDOC(1)'. The title name should not contain white
space and the manual section number is a single digit optionally
followed by a single character.

The NAME Section
~~~~~~~~~~~~~~~~
The first manpage section is mandatory, must be titled 'NAME' and must
contain a single paragraph (usually a single line) consisting of a
list of one or more comma separated command name(s) separated from the
command purpose by a dash character. The dash must have at least one
white space character on either side. For example:

  printf, fprintf, sprintf - print formatted output

The SYNOPSIS Section
~~~~~~~~~~~~~~~~~~~~
The second manpage section is mandatory and must be titled 'SYNOPSIS'.

refmiscinfo attributes
~~~~~~~~~~~~~~~~~~~~~~
In addition to the automatically created man page <<X60,intrinsic
attributes>> you can assign DocBook
http://www.docbook.org/tdg5/en/html/refmiscinfo.html[refmiscinfo]
element 'source', 'version' and 'manual' values using AsciiDoc
`{mansource}`, `{manversion}` and `{manmanual}` attributes
respectively. This example is from the AsciiDoc header of a man page
source file:

  :man source:   AsciiDoc
  :man version:  {revnumber}
  :man manual:   AsciiDoc Manual


[[X78]]
Mathematical Formulas
---------------------
The 'asciimath' and 'latexmath' <<X77,passthrough macros>> along with
'asciimath' and 'latexmath'  <<X76,passthrough blocks>> provide a
(backend dependent) mechanism for rendering mathematical formulas. You
can use the following math markups:

NOTE: The 'latexmath' macro used to include 'LaTeX Math' in DocBook
outputs is not the same as the 'latexmath' macro used to include
'LaTeX MathML' in XHTML outputs.  'LaTeX Math' applies to DocBook
outputs that are processed by <<X31,dblatex>> and is normally used to
generate PDF files.  'LaTeXMathML' is very much a subset of 'LaTeX
Math' and applies to XHTML documents.

LaTeX Math
~~~~~~~~~~
ftp://ftp.ams.org/pub/tex/doc/amsmath/short-math-guide.pdf[LaTeX
math] can be included in documents that are processed by
<<X31,dblatex(1)>>.  Example inline formula:

  latexmath:[$C = \alpha + \beta Y^{\gamma} + \epsilon$]

For more examples see the http://www.methods.co.nz/asciidoc/[AsciiDoc
website] or the distributed `doc/latexmath.txt` file.

ASCIIMathML
~~~~~~~~~~~
/////////////////////////////////////////////////////////////////////
The older ASCIIMathML 1.47 version is used instead of version 2
because:

1. Version 2 doesn't work when embedded.
2. Version 2 is much larger.
/////////////////////////////////////////////////////////////////////

http://www1.chapman.edu/~jipsen/mathml/asciimath.html[ASCIIMathML]
formulas can be included in XHTML documents generated using the
'xhtml11' backend. To enable ASCIIMathML support you must define the
'asciimath' attribute, for example using the `-a asciimath`
command-line option.  Example inline formula:

  asciimath:[`x/x={(1,if x!=0),(text{undefined},if x=0):}`]

For more examples see the http://www.methods.co.nz/asciidoc/[AsciiDoc
website] or the distributed `doc/asciimathml.txt` file.

LaTeXMathML
~~~~~~~~~~~
/////////////////////////////////////////////////////////////////////
There is an http://math.etsu.edu/LaTeXMathML/[extended LaTeXMathML
version] by Jeff Knisley, in addition to a JavaScript file it requires
the inclusion of a CSS file.
/////////////////////////////////////////////////////////////////////

'LaTeXMathML' allows LaTeX Math style formulas to be included in XHTML
documents generated using the AsciiDoc 'xhtml11' backend.  AsciiDoc
uses the
http://www.maths.nottingham.ac.uk/personal/drw/lm.html[original
LaTeXMathML] by Douglas Woodall.  'LaTeXMathML' is derived from
ASCIIMathML and is for users who are more familiar with or prefer
using LaTeX math formulas (it recognizes a subset of LaTeX Math, the
differences are documented on the 'LaTeXMathML' web page).  To enable
LaTeXMathML support you must define the 'latexmath' attribute, for
example using the `-a latexmath` command-line option.  Example inline
formula:

  latexmath:[$\sum_{n=1}^\infty \frac{1}{2^n}$]

For more examples see the http://www.methods.co.nz/asciidoc/[AsciiDoc
website] or the distributed `doc/latexmathml.txt` file.

There are more examples on the
http://www.methods.co.nz/asciidoc/[AsciiDoc website].

MathML
~~~~~~
http://www.w3.org/Math/[MathML] is a low level XML markup for
mathematics. AsciiDoc has no macros for MathML but users familiar with
this markup could use passthrough macros and passthrough blocks to
include MathML in output documents.


[[X7]]
Configuration Files
-------------------
AsciiDoc source file syntax and output file markup is largely
controlled by a set of cascading, text based, configuration files.  At
runtime The AsciiDoc default configuration files are combined with
optional user and document specific configuration files.

Configuration File Format
~~~~~~~~~~~~~~~~~~~~~~~~~
Configuration files contain named sections. Each section begins with a
section name in square brackets []. The section body consists of the
lines of text between adjacent section headings.

- Section names consist of one or more alphanumeric, underscore or
  dash characters and cannot begin or end with a dash.
- Lines starting with a hash character "#" are treated as comments and
  ignored.
- Same named sections and section entries override previously loaded
  sections and section entries (this is sometimes referred to as
  'cascading').  Consequently, downstream configuration files need
  only contain those sections and section entries that need to be
  overridden.

TIP: When creating custom configuration files you only need to include
the sections and entries that differ from the default configuration.

TIP: The best way to learn about configuration files is to read the
default configuration files in the AsciiDoc distribution in
conjunction with asciidoc(1) output files. You can view configuration
file load sequence by turning on the asciidoc(1) `-v` (`--verbose`)
command-line option.

AsciiDoc reserves the following section names for specific purposes:

miscellaneous::
        Configuration options that don't belong anywhere else.
attributes::
        Attribute name/value entries.
specialcharacters::
        Special characters reserved by the backend markup.
tags::
        Backend markup tags.
quotes::
        Definitions for quoted inline character formatting.
specialwords::
        Lists of words and phrases singled out for special markup.
replacements, replacements2::
        Find and replace substitution definitions.
specialsections::
        Used to single out special section names for specific markup.
macros::
        Macro syntax definitions.
titles::
        Heading, section and block title definitions.
paradef-*::
        Paragraph element definitions.
blockdef-*::
        DelimitedBlock element definitions.
listdef-*::
        List element definitions.
listtags-*::
        List element tag definitions.
tabledef-*::
        Table element definitions.
tabletags-*::
        Table element tag definitions.

Each line of text in these sections is a 'section entry'. Section
entries share the following syntax:

name=value::
        The entry value is set to value.
name=::
        The entry value is set to a zero length string.
name!::
        The entry is undefined (deleted from the configuration). This
        syntax only applies to 'attributes' and 'miscellaneous'
        sections.

.Section entry behavior
- All equals characters inside the `name` must be escaped with a
  backslash character.
- `name` and `value` are stripped of leading and trailing white space.
- Attribute names, tag entry names and markup template section names
  consist of one or more alphanumeric, underscore or dash characters.
  Names should not begin or end with a dash.
- A blank configuration file section (one without any entries) deletes
  any preceding section with the same name (applies to non-markup
  template sections).


Miscellaneous section
~~~~~~~~~~~~~~~~~~~~~
The optional `[miscellaneous]` section specifies the following
`name=value` options:

newline::
        Output file line termination characters. Can include any
        valid Python string escape sequences. The default value is
        `\r\n` (carriage return, line feed). Should not be quoted or
        contain explicit spaces (use `\x20` instead). For example:

        $ asciidoc -a 'newline=\n' -b docbook mydoc.txt

outfilesuffix::
        The default extension for the output file, for example
        `outfilesuffix=.html`. Defaults to backend name.
tabsize::
        The number of spaces to expand tab characters, for example
        `tabsize=4`. Defaults to 8. A 'tabsize' of zero suppresses tab
        expansion (useful when piping included files through block
        filters). Included files can override this option using the
        'tabsize' attribute.
pagewidth, pageunits::
        These global table related options are documented in the
        <<X4,Table Configuration File Definitions>> sub-section.

NOTE: `[miscellaneous]` configuration file entries can be set using
the asciidoc(1) `-a` (`--attribute`) command-line option.

Titles section
~~~~~~~~~~~~~~
sectiontitle::
        Two line section title pattern. The entry value is a Python
        regular expression containing the named group 'title'.

underlines::
        A comma separated list of document and section title underline
        character pairs starting with the section level 0 and ending
        with section level 4 underline. The default setting is:

        underlines="==","--","~~","^^","++"

sect0...sect4::
        One line section title patterns. The entry value is a Python
        regular expression containing the named group 'title'.

blocktitle::
        <<X42,BlockTitle element>> pattern.  The entry value is a
        Python regular expression containing the named group 'title'.

subs::
        A comma separated list of substitutions that are performed on
        the document header and section titles. Defaults to 'normal'
        substitution.

Tags section
~~~~~~~~~~~~
The `[tags]` section contains backend tag definitions (one per
line). Tags are used to translate AsciiDoc elements to backend
markup.

An AsciiDoc tag definition is formatted like
`<tagname>=<starttag>|<endtag>`. For example:

  emphasis=<em>|</em>

In this example asciidoc(1) replaces the | character with the
emphasized text from the AsciiDoc input file and writes the result to
the output file.

Use the `{brvbar}` attribute reference if you need to include a | pipe
character inside tag text.

Attributes section
~~~~~~~~~~~~~~~~~~
The optional `[attributes]` section contains predefined attributes.

If the attribute value requires leading or trailing spaces then the
text text should be enclosed in quotation mark (") characters.

To delete a attribute insert a `name!` entry in a downstream
configuration file or use the asciidoc(1) `--attribute name!`
command-line option (an attribute name suffixed with a `!` character
deletes the attribute)

Special Characters section
~~~~~~~~~~~~~~~~~~~~~~~~~~
The `[specialcharacters]` section specifies how to escape characters
reserved by the backend markup. Each translation is specified on a
single line formatted like:

  <special_character>=<translated_characters>

Special characters are normally confined to those that resolve
markup ambiguity (in the case of SGML/XML markups the ampersand, less
than and greater than characters).  The following example causes all
occurrences of the `<` character to be replaced by `&lt;`.

  <=&lt;

Quoted Text section
~~~~~~~~~~~~~~~~~~~
Quoting is used primarily for text formatting.  The `[quotes]` section
defines AsciiDoc quoting characters and their corresponding backend
markup tags.  Each section entry value is the name of a of a `[tags]`
section entry. The entry name is the character (or characters) that
quote the text.  The following examples are taken from AsciiDoc
configuration files:

  [quotes]
  _=emphasis

  [tags]
  emphasis=<em>|</em>

You can specify the left and right quote strings separately by
separating them with a | character, for example:

  ``|''=quoted

Omitting the tag will disable quoting, for example, if you don't want
superscripts or subscripts put the following in a custom configuration
file or edit the global `asciidoc.conf` configuration file:

  [quotes]
  ^=
  ~=

<<X52,Unconstrained quotes>> are differentiated by prefixing the tag
name with a hash character, for example:

  __=#emphasis

.Quoted text behavior
- Quote characters must be non-alphanumeric.
- To minimize quoting ambiguity try not to use the same quote
  characters in different quote types.

Special Words section
~~~~~~~~~~~~~~~~~~~~~
The `[specialwords]` section is used to single out words and phrases
that you want to consistently format in some way throughout your
document without having to repeatedly specify the markup. The name of
each entry corresponds to a markup template section and the entry
value consists of a list of words and phrases to be marked up. For
example:

  [specialwords]
  strongwords=NOTE: IMPORTANT:

  [strongwords]
  <strong>{words}</strong>

The examples specifies that any occurrence of `NOTE:` or `IMPORTANT:`
should appear in a bold font.

Words and word phrases are treated as Python regular expressions: for
example, the word `^NOTE:` would only match `NOTE:` if appeared at
the start of a line.

AsciiDoc comes with three built-in Special Word types:
'emphasizedwords', 'monospacedwords' and 'strongwords', each has a
corresponding (backend specific) markup template section. Edit the
configuration files to customize existing Special Words and to add new
ones.

.Special word behavior
- Word list entries must be separated by space characters.
- Word list entries with embedded spaces should be enclosed in quotation (")
  characters.
- A `[specialwords]` section entry of the form
  +name=word1{nbsp}[word2...]+ adds words to existing `name` entries.
- A `[specialwords]` section entry of the form `name` undefines
  (deletes) all existing `name` words.
- Since word list entries are processed as Python regular expressions
  you need to be careful to escape regular expression special
  characters.
- By default Special Words are substituted before Inline Macros, this
  may lead to undesirable consequences. For example the special word
  `foobar` would be expanded inside the macro call
  `http://www.foobar.com[]`.  A possible solution is to emphasize
  whole words only by defining the word using regular expression
  characters, for example `\bfoobar\b`.
- If the first matched character of a special word is a backslash then
  the remaining characters are output without markup i.e. the
  backslash can be used to escape special word markup.  For example
  the special word `\\?\b[Tt]en\b` will mark up the words `Ten` and
  `ten` only if they are not preceded by a backslash.

[[X10]]
Replacements section
~~~~~~~~~~~~~~~~~~~~
`[replacements]` and `[replacements2]` configuration file entries
specify find and replace text and are formatted like:

  <find_pattern>=<replacement_text>

The find text can be a Python regular expression; the replace text can
contain Python regular expression group references.

Use Replacement shortcuts for often used macro references, for
example (the second replacement allows us to backslash escape the
macro name):

  NEW!=image:./images/smallnew.png[New!]
  \\NEW!=NEW!

.Replacement behavior
- The built-in replacements can be escaped with a backslash.
- If the find or replace text has leading or trailing spaces then the
  text should be enclosed in quotation (") characters.
- Since the find text is processed as a regular expression you need to
  be careful to escape regular expression special characters.
- Replacements are performed in the same order they appear in the
  configuration file replacements section.

Markup Template Sections
~~~~~~~~~~~~~~~~~~~~~~~~
Markup template sections supply backend markup for translating
AsciiDoc elements.  Since the text is normally backend dependent
you'll find these sections in the backend specific configuration
files. Template sections differ from other sections in that they
contain a single block of text instead of per line 'name=value'
entries. A markup template section body can contain:

- Attribute references
- System macro calls.
- A document content placeholder

The document content placeholder is a single | character and is
replaced by text from the source element.  Use the `{brvbar}`
attribute reference if you need a literal | character in the template.

[[X27]]
Configuration File Names and Locations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Configuration files have a `.conf` file name extension; they are
loaded implicitly (using predefined file names and locations) or
explicitly (using the asciidoc(1) `-f` (`--conf-file`) command-line
option).

Implicit configuration files are loaded from the following directories
in the following order:

1. The global configuration directory (normally `/etc/asciidoc` or
   `/usr/local/etc/asciidoc`) if it exists.
2. The directory containing the asciidoc executable.
3. The user's `$HOME/.asciidoc` directory (if it exists).
4. The directory containing the AsciiDoc source file.

The following implicit configuration files from each of the above
locations are loaded in the following order:

1. `asciidoc.conf`
2. `<backend>.conf`
3. `<backend>-<doctype>.conf`

Where `<backend>` and `<doctype>` are values specified by the
asciidoc(1) `-b` (`--backend`) and `-d` (`--doctype`) command-line
options.

Next, configuration files named like the source file will be
automatically loaded if they are found in the source file directory.
For example if the source file is `mydoc.txt` and the
`--backend=html4` option is used then asciidoc(1) will look for
`mydoc.conf` and `mydoc-html4.conf` in that order.

Implicit configuration files that don't exist will be silently
skipped.

The user can explicitly specify additional configuration files using
the asciidoc(1) `-f` (`--conf-file`) command-line option.  The `-f`
option can be specified multiple times, in which case configuration
files will be processed in the order they appear on the command-line.

For example, when we translate our AsciiDoc document `mydoc.txt` with:

  $ asciidoc -f extra.conf mydoc.txt

The last configuration file to load is the language configuration file
`lang-<lang>.conf`. `<lang>` is the value of the AsciiDoc `lang`
attribute (defaults to `en` (English)). You can set the `lang`
attribute inside the AsciiDoc source file using an
<<X18,AttributeEntry>> provided it is the first entry and provided it
precedes the document header, for example:

  :lang: es

Configuration files (if they exist) will be processed in the following
order:

1. First default global configuration files from the asciidoc program
   directory are loaded:

   asciidoc.conf
   xhtml11.conf

2. Then, from the users home `~/.asciidoc` directory.  This is were
   you put customization specific to  your own asciidoc documents:

   asciidoc.conf
   xhtml11.conf
   xhtml11-article.conf

3. Next from the source document project directory (the first three
   apply to all documents in the directory, the last two are specific
   to the mydoc.txt document):

   asciidoc.conf
   xhtml11.conf
   xhtml11-article.conf
   mydoc.conf
   mydoc-xhtml11.conf

4. Finally the file specified by the `-f` command-line option is
   loaded:

   extra.conf

TIP: Use the asciidoc(1) `-v` (`--verbose`) command-line option to see
which configuration files are loaded and the order in which they are
loaded.


Document Attributes
-------------------
A document attribute is comprised of a 'name' and a textual 'value'
and is used for textual substitution in AsciiDoc documents and
configuration files. An attribute reference (an attribute name
enclosed in braces) is replaced by its corresponding attribute
value.

There are four sources of document attributes (from highest to lowest
precedence):

- Command-line attributes.
- AttributeEntry, AttributeList, Macro and BlockId elements.
- Configuration file `[attributes]` sections.
- Intrinsic attributes.

Within each of these divisions the last processed entry takes
precedence.

IMPORTANT: If an attribute is not defined then the line containing the
attribute reference is dropped. This property is used extensively in
AsciiDoc configuration files to facilitate conditional markup
generation.


[[X18]]
Attribute Entries
-----------------
The `AttributeEntry` block element allows document attributes to be
assigned within an AsciiDoc document. Attribute entries are added to
the global document attributes dictionary. The attribute name/value
syntax is a single line like:

  :<name>: <value>

For example:

  :Author Initials: JB

This will set an attribute reference `{authorinitials}` to the value
'JB' in the current document.

To delete (undefine) an attribute use the following syntax:

  :<name>!:

.AttributeEntry behavior
- The attribute entry line begins with colon -- no white space allowed
  in left margin.
- AsciiDoc converts the `<name>` to a legal attribute name (lower
  case, alphanumeric and dash characters only -- all other characters
  deleted). This allows more reader friendly text to be used.
- Leading and trailing white space is stripped from the `<value>`.
- If the `<value>` is blank then the corresponding attribute value is
  set to an empty string.
- Attribute references contained in the entry `<value>` will be
  expanded.
- By default AttributeEntry values are substituted for
  `specialcharacters` and `attributes` (see above), if you want to
  change or disable AttributeEntry substitution use the <<X77,pass:[]
  inline macro>> syntax.
- Attribute entries in the document Header are available for header
  markup template substitution.
- Attribute elements override configuration file and intrinsic
  attributes but do not override command-line attributes.

Here are some more attribute entry examples:

---------------------------------------------------------------------
AsciiDoc User Manual
====================
:author:    Stuart Rackham
:email:     srackham@gmail.com
:revdate:   April 23, 2004
:revnumber: 5.1.1
:keywords: linux, ralink, debian, wireless
---------------------------------------------------------------------

Which creates these attributes:

  {author}, {firstname}, {lastname}, {authorinitials}, {email},
  {revdate}, {revnumber}, {keywords}

The preceding example is equivalent to the standard AsciiDoc two line
document header (actually it's a little bit different because of the
addition of the `{keywords}` attribute).

Setting configuration entries
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A variant of the Attribute Entry syntax allows configuration file
entries to be set from within an AsciiDoc document:

  :<section_name>.<entry_name>: <entry_value>

Where `<section_name>` is the configuration section name,
`<entry_name>` is the name of the entry and `<entry_value>` is the
optional entry value. This example sets the default labeled list style
to 'horizontal':

  :listdef-labeled.style: horizontal

It is exactly equivalent to a configuration file containing:

  [listdef-labeled]
  style=horizontal

No substitution is performed on configuration file attribute entries.

[[X62]]
.Attribute entries promote clarity and eliminate repetition
*********************************************************************
URLs and file names in AsciiDoc macros are often quite long -- they
break paragraph flow and readability suffers.  The problem is
compounded by redundancy if the same name is used repeatedly.
Attribute entries can be used to make your documents easier to read
and write, here are some examples:

  :1:         http://freshmeat.net/projects/asciidoc/
  :homepage:  http://hg.sharesource.org/asciidoc/[AsciiDoc home page]
  :new:       image:./images/smallnew.png[]
  :footnote1: footnote:[A meaningless latin term]

  Using previously defined attributes: See the {1}[Freshmeat summary]
  or the {homepage} for something new {new}. Lorem ispum {footnote1}.

.Note
- The attribute entry definition must precede it's usage.
- You are not limited to URLs or file names, entire macro calls or
  arbitrary lines of text can be abbreviated.
- Shared attributes entries could be grouped into a separate file and
  <<X63,included>> in multiple documents.
*********************************************************************


[[X21]]
Attribute Lists
---------------
- An attribute list is a comma separated list of attribute values.
- The entire list is enclosed in square brackets.
- Attribute lists are used to pass parameters to macros, blocks (using
  the <<X79,AttributeList element>>) and inline quotes.

The list consists of zero or more positional attribute values followed
by zero or more named attribute values.  Here are three examples: a
single unquoted positional attribute; three unquoted positional
attribute values; one positional attribute followed by two named
attributes; the unquoted attribute value in the final example contains
comma (`&#44;`) and double-quote (`&#34;`) character entities:

  [Hello]
  [quote, Bertrand Russell, The World of Mathematics (1956)]
  ["22 times", backcolor="#0e0e0e", options="noborders,wide"]
  [A footnote&#44; &#34;with an image&#34; image:smallnew.png[]]

.Attribute list behavior
- If one or more attribute values contains a comma the all string
  values must be quoted (enclosed in quotation mark characters).
- If the list contains any named or quoted attributes then all string
  attribute values must be quoted.
- To include a quotation mark (") character in a quoted attribute
  value the the quotation mark must be escaped with a backslash.
- List attributes take precedence over existing attributes.
- List attributes can only be referenced in configuration file markup
  templates and tags, they are not available elsewhere in the
  document.
- Setting a named attribute to `None` undefines the attribute.
- Positional attributes are referred to as `{1}`,`{2}`,`{3}`,...
- Attribute `{0}` refers to the entire list (excluding the enclosing
  square brackets).
- Named attribute names cannot contain dash characters (as they can
  elsewhere).

[[X75]]
Options attribute
~~~~~~~~~~~~~~~~~
If the attribute list contains an attribute named `options` it is
processed as a comma separated list of option names:

- Each name generates an attribute named like `<option>-option` (where
  `<option>` is the option name) with an empty string value.  For
  example `[options="opt1,opt2,opt3"]` is equivalent to setting the
  following three attributes
  `[opt1-option="",opt2-option="",opt2-option=""]`.
- If you define a an option attribute globally (for example with an
  <<X18,attribute entry>>) then it will apply to all elements in the
  document.
- AsciiDoc implements a number of predefined options which are listed
  in the <<X74,Attribute Options appendix>>.

Macro Attribute lists
~~~~~~~~~~~~~~~~~~~~~
Macros calls are suffixed with an attribute list. The list may be
empty but it cannot be omitted. List entries are used to pass
attribute values to macro markup templates.


Attribute References
--------------------
An attribute references is an attribute name (possibly followed by an
additional parameters) enclosed in braces.  When an attribute
reference is encountered it is evaluated and replaced by its
corresponding text value.  If the attribute is undefined the line
containing the attribute is dropped.

There are three types of attribute reference: 'Simple', 'Conditional'
and 'System'.

.Attribute reference evaluation
- You can suppress attribute reference expansion by placing a
  backslash character immediately in front of the opening brace
  character.
- By default attribute references are not expanded in
  'LiteralParagraphs', 'ListingBlocks' or 'LiteralBlocks'.
- Attribute substitution proceeds line by line in reverse line order.
- Attribute reference evaluation is performed in the following order:
  'Simple' then 'Conditional' and finally 'System'.

Simple Attributes References
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Simple attribute references take the form `{<name>}`. If the
attribute name is defined its text value is substituted otherwise the
line containing the reference is dropped from the output.

Conditional Attribute References
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Additional parameters are used in conjunction with attribute names to
calculate a substitution value. Conditional attribute references take
the following forms:

`{<names>=<value>}`::
        `<value>` is substituted if the attribute `<names>` is
        undefined otherwise its value is substituted. `<value>` can
        contain simple attribute references.

`{<names>?<value>}`::
        `<value>` is substituted if the attribute `<names>` is defined
        otherwise an empty string is substituted.  `<value>` can
        contain simple attribute references.

`{<names>!<value>}`::
        `<value>` is substituted if the attribute `<names>` is
        undefined otherwise an empty string is substituted.  `<value>`
        can contain simple attribute references.

`{<names>#<value>}`::
        `<value>` is substituted if the attribute `<names>` is defined
        otherwise the undefined attribute entry causes the containing
        line to be dropped.  `<value>` can contain simple attribute
        references.

`{<names>%<value>}`::
        `<value>` is substituted if the attribute `<names>` is not
        defined otherwise the containing line is dropped.  `<value>`
        can contain simple attribute references.

`{<names>@<regexp>:<value1>[:<value2>]}`::
        `<value1>` is substituted if the value of attribute `<names>`
        matches the regular expression `<regexp>` otherwise `<value2>`
        is substituted. If attribute `<names>` is not defined the
        containing line is dropped. If `<value2>` is omitted an empty
        string is assumed. The values and the regular expression can
        contain simple attribute references.  To embed colons in the
        values or the regular expression escape them with backslashes.

`{<names>$<regexp>:<value1>[:<value2>]}`::
        Same behavior as the previous ternary attribute except for
        the following cases:

        `{<names>$<regexp>:<value>}`;;
                Substitutes `<value>` if `<names>` matches `<regexp>`
                otherwise the result is undefined and the containing
                line is dropped.

        `{<names>$<regexp>::<value>}`;;
                Substitutes `<value>` if `<names>` does not match
                `<regexp>` otherwise the result is undefined and the
                containing line is dropped.

The attribute `<names>` parameter normally consists of a single
attribute name but it can be any one of the following:

- A single attribute name which evaluates to the attributes value.
- Multiple ',' separated attribute names which evaluates to an empty
  string if one or more of the attributes is defined, otherwise it's
  value is undefined.
- Multiple '+' separated attribute names which evaluates to an empty
  string if all of the attributes are defined, otherwise it's value is
  undefined.

Conditional attributes with single attribute names are evaluated first
so they can be used inside the multi-attribute conditional `<value>`.

Conditional attribute examples
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Conditional attributes are mainly used in AsciiDoc configuration
files -- see the distribution `.conf` files for examples.

Attribute equality test::
  If `{backend}` is `docbook` or `xhtml11` the example evaluates to
  ``DocBook or XHTML backend'' otherwise it evaluates to ``some other
  backend'':

  {backend@docbook|xhtml11:DocBook or XHTML backend:some other backend}

Attribute value map::
  This example maps the `frame` attribute values [`topbot`, `all`,
  `none`, `sides`] to [`hsides`, `border`, `void`, `vsides`]:

  {frame@topbot:hsides}{frame@all:border}{frame@none:void}{frame@sides:vsides}


[[X24]]
System Attribute References
~~~~~~~~~~~~~~~~~~~~~~~~~~~
System attribute references generate the attribute text value by
executing a predefined action that is parametrized by a single
argument. The syntax is `{<action>:<argument>}`.

`{counter:<attrname>[:<seed>]}`::
        Increments the document attribute (if the attribute is
        undefined it is set to `1`). Returns the new attribute value.

        - Counters generate global (document wide) attributes.
        - The optional `<seed>` specifies the counter's initial value;
          it can be a number or a single letter; defaults to '1'.
        - `<seed>` can contain simple and conditional attribute
          references.
        - The 'counter' system attribute will not be executed if the
          containing line is dropped by the prior evaluation of an
          undefined attribute.

`{eval:<expression>}`::
        Substitutes the result of the Python `<expression>`.

        - If `<expression>` evaluates to `None` or `False` the
          reference is deemed undefined and the line containing the
          reference is dropped from the output.
        - If the expression evaluates to `True` the attribute
          evaluates to an empty string.
        - `<expression>` can contain simple and conditional attribute
          references.
        - The 'eval' system attribute can be nested inside other
          system attributes.

`{eval3:<command>}`::
        Passthrough version of `{eval:<expression>}` -- the generated
        output is written directly to the output without any further
        substitutions.

`{include:<filename>}`::
        Substitutes contents of the file named `<filename>`.

        - The included file is read at the time of attribute
          substitution.
        - If the file does not exist a warning is emitted and the line
          containing the reference is dropped from the output file.
        - Tabs are expanded based on the current 'tabsize' attribute
          value.

`{set:<attrname>[!][:<value>]}`::
        Sets or unsets document attribute. Normally only used in
        configuration file markup templates (use
        <<X18,AttributeEntries>> in AsciiDoc documents).

        - If the attribute name is followed by an exclamation mark
          the attribute becomes undefined.
        - If `<value>` is omitted the attribute is set to a blank
          string.
        - `<value>` can contain simple and conditional attribute
          references.
        - Returns a blank string unless the attribute is undefined in
          which case the return value is undefined and the enclosing
          line will be dropped.

`{sys:<command>}`::
        Substitutes the stdout generated by the execution of the shell
        `<command>`.

`{sys2:<command>}`::
        Substitutes the stdout and stderr generated by the execution
        of the shell `<command>`.

`{sys3:<command>}`::
        Passthrough version of `{sys:<command>}` -- the generated
        output is written directly to the output without any further
        substitutions.

.System reference behavior
- System attribute arguments can contain non-system attribute
  references.
- Closing brace characters inside system attribute arguments must be
  escaped them with a backslash.

[[X60]]
Intrinsic Attributes
--------------------
Intrinsic attributes are simple attributes that are created
automatically from AsciiDoc document header parameters, asciidoc(1)
command-line arguments, execution parameters along with attributes
defined in the default configuration files.  Here's the list of
predefined intrinsic attributes:

  {amp}                 ampersand (&) character
  {asciidoc-dir}        the asciidoc(1) application directory
  {asciidoc-file}       the full path name of the asciidoc(1) script
  {asciidoc-version}    the version of asciidoc(1)
  {author}              author's full name
  {authored}            empty string '' if {author} or {email} defined,
  {authorinitials}      author initials (from document header)
  {backend-<backend>}   empty string ''
  {<backend>-<doctype>} empty string ''
  {backend}             document backend specified by `-b` option
  {backslash}           backslash character
  {basebackend-<base>}  empty string ''
  {basebackend}         html or docbook
  {brvbar}              broken vertical bar (|) character
  {revdate}             document revision date (from document header)
  {docdate}             document last modified date
  {doctime}             document last modified time
  {docname}             document file name without extension
  {docfile}             document file name  (note 5)
  {docdir}              document input directory name  (note 5)
  {doctitle}            document title (from document header)
  {doctype-<doctype>}   empty string ''
  {doctype}             document type specified by `-d` option
  {email}               author's email address (from document header)
  {empty}               empty string ''
  {encoding}            specifies input and output encoding
  {filetype-<fileext>}  empty string ''
  {filetype}            output file name file extension
  {firstname}           author first name (from document header)
  {gt}                  greater than (>) character
  {id}                  running block id generated by BlockId elements
  {indir}               input file directory name (note 2,5)
  {infile}              input file name (note 2,5)
  {lastname}            author last name (from document header)
  {level}               title level 1..4 (in section titles)
  {listindex}           the list index (1..) of the most recent list item
  {localdate}           the current date
  {localtime}           the current time
  {lt}                  less than (<) character
  {manname}             manpage name (defined in NAME section)
  {manpurpose}          manpage (defined in NAME section)
  {mantitle}            document title minus the manpage volume number
  {manvolnum}           manpage volume number (1..8) (from document header)
  {middlename}          author middle name (from document header)
  {nbsp}                Non-breaking space entity
  {outdir}              document output directory name (note 2)
  {outfile}             output file name (note 2)
  {reftext}             running block xreflabel generated by BlockId elements
  {revnumber}           document revision number (from document header)
  {sectnum}             formatted section number (in section titles)
  {showcomments}        send comment lines to the output
  {title}               section title (in titled elements)
  {two-colons}          Two colon characters
  {two-semicolons}      Two semicolon characters
  {user-dir}            the ~/.asciidoc directory (if it exists)
  {verbose}             defined as '' if --verbose command option specified
  {zwsp}                Zero-width space.

.NOTES
1. Intrinsic attributes are global so avoid defining custom attributes
   with the same names.

2. `{outfile}`, `{outdir}`, `{infile}`, `{indir}` attributes are
   effectively read-only (you can set them but it won't affect the
   input or output file paths).

3. See also the <<X33,xhtml11>> subsection for attributes that relate
   to AsciiDoc XHTML file generation.

4. The entries that translate to blank strings are designed to be used
   for conditional text inclusion. You can also use the `ifdef`,
   `ifndef` and `endif` System macros for conditional inclusion.
   footnote:[Conditional inclusion using `ifdef` and `ifndef` macros
   differs from attribute conditional inclusion in that the former
   occurs when the file is read while the latter occurs when the
   contents are written.]

5. `{docfile}` and `{docdir}` refer to root document specified on
   the asciidoc(1) command-line; `{infile}` and `{indir}` refer to
   the current input file which may be the root document or an
   included file. While the input is being read from the standard
   input (`stdin`) these attributes are undefined.

[[X73]]
Block Element Definitions
-------------------------
The syntax and behavior of Paragraph, DelimitedBlock, List and Table
block elements is determined by block definitions contained in
<<X7,AsciiDoc configuration file>> sections.

Each definition consists of a section title followed by one or more
section entries. Each entry defines a block parameter controlling some
aspect of the block's behavior. Here's an example:

---------------------------------------------------------------------
[blockdef-listing]
delimiter=^-{4,}$
template=listingblock
presubs=specialcharacters,callouts
---------------------------------------------------------------------

AsciiDoc Paragraph, DelimitedBlock, List and Table block elements
share a common subset of configuration file parameters:

delimiter::
  A Python regular expression that matches the first line of a block
  element -- in the case of DelimitedBlocks it also matches the last
  line. Table elements don't have an explicit delimiter -- they
  synthesize their delimiters at runtime.

template::
  The name of the configuration file markup template section that will
  envelope the block contents. The pipe | character is substituted for
  the block contents. List elements use a set of (list specific) tag
  parameters instead of a single template.

options::
  A comma delimited list of element specific option names. In addition
  to being used internally, options are available during markup tag
  and template substitution as attributes with an empty string value
  named like `<option>-option` (where `<option>` is the option name).

subs, presubs, postsubs::
  * 'presubs' and 'postsubs' are lists of comma separated substitutions that are
    performed on the block contents. 'presubs' is applied first,
    'postsubs' (if specified) second.

  * 'subs' is an alias for 'presubs'.

  * If a 'filter' is allowed (Paragraphs, DelimitedBlocks and Tables)
    and has been specified then 'presubs' and 'postsubs' substitutions
    are performed before and after the filter is run respectively.

  * Allowed values: 'specialcharacters', 'quotes', 'specialwords',
    'replacements', 'macros', 'attributes', 'callouts'.

  * The following composite values are also allowed:

    'none';;
        No substitutions.
    'normal';;
        The following substitutions:
        'specialcharacters','quotes','attributes','specialwords',
        'replacements','macros'.
    'verbatim';;
        'specialcharacters' and 'callouts' substitutions.

  * 'normal' and 'verbatim' substitutions can be redefined by with
    `subsnormal` and `subsverbatim` entries in a configuration file
    `[miscellaneous]` section.

  * The substitutions are processed in the order in which they are
    listed and can appear more than once.

filter::
  This optional entry specifies an executable shell command for
  processing block content (Paragraphs, DelimitedBlocks and Tables).
  The filter command can contain attribute references.

posattrs::
  Optional comma separated list of positional attribute names. This
  list maps positional attributes (in the block's <<X21,attribute
  list>>) to named block attributes. The following example, from the
  QuoteBlock definition, maps the first and section positional
  attributes:

  posattrs=attribution,citetitle

style::
  This optional parameter specifies the default style name.


<stylename>-style::
  Optional style definition (see <<X23,Styles>> below).

The following block parameters behave like document attributes and can
be set in block attribute lists and style definitions: 'template',
'options', 'subs', 'presubs', 'postsubs', 'filter'.

[[X23]]
Styles
~~~~~~
A style is a set of block attributes bundled as a single named
attribute. The following example defines a style named 'verbatim':

  verbatim-style=template="literalblock",subs="verbatim"

- All style parameter names must be suffixed with `-style` and the
  style parameter value is in the form of a list of <<X21,named
  attributes>>.
- Multi-item style attributes ('subs','presubs','postsubs','posattrs')
  must be specified using Python tuple syntax rather than a simple
  list of values as they in separate entries e.g.
  `postsubs=("callouts",)` not `postsubs="callouts"`.

Paragraphs
~~~~~~~~~~
Paragraph translation is controlled by `[paradef*]` configuration file
section entries. Users can define new types of paragraphs and modify
the behavior of existing types by editing AsciiDoc configuration
files.

Here is the shipped Default paragraph definition:

--------------------------------------------------------------------
[paradef-default]
delimiter=(?P<text>\S.*)
template=paragraph
--------------------------------------------------------------------

The Default paragraph definition has a couple of special properties:

1. It must exist and be defined in a configuration file section named
   `[paradef-default]`.
2. Irrespective of its position in the configuration files default
   paragraph document matches are attempted only after trying all
   other paragraph types.

Paragraph specific block parameter notes:

delimiter::
  This regular expression must contain the named group 'text' which
  matches the text on the first line.  Paragraphs are terminated by a
  blank line, the end of file, or the start of a DelimitedBlock.

options::
  The 'listelement' option specifies that paragraphs of this type will
  automatically be considered part of immediately preceding list
  items.

.Paragraph processing proceeds as follows:
1. The paragraph text is aligned to the left margin.
2. Optional 'presubs' inline substitutions are performed on the
   paragraph text.
3. If a filter command is specified it is executed and the paragraph
   text piped to its standard input; the filter output replaces the
   paragraph text.
4. Optional 'postsubs' inline substitutions are performed on the
   paragraph text.
5. The paragraph text is enveloped by the paragraph's markup template
   and written to the output file.

Delimited Blocks
~~~~~~~~~~~~~~~~
DelimitedBlock 'options' values are:

sectionbody::
    The block contents are processed as a SectionBody.

skip::
    The block is treated as a comment (see <<X26,CommentBlocks>>).

'presubs', 'postsubs' and 'filter' entries are meaningless when
'sectionbody' or 'skip' options are set.

DelimitedBlock processing proceeds as follows:

1. Optional 'presubs' substitutions are performed on the block
   contents.
2. If a filter is specified it is executed and the block's contents
   piped to its standard input. The filter output replaces the block
   contents.
3. Optional 'postsubs' substitutions are performed on the block
   contents.
4. The block contents is enveloped by the block's markup template and
   written to the output file.

TIP: Attribute expansion is performed on the block filter command
before it is executed, this is useful for passing arguments to the
filter.

Lists
~~~~~
List behavior and syntax is determined by `[listdef*]` configuration
file sections. The user can change existing list behavior and add new
list types by editing configuration files.

List specific block definition notes:

type::
  This is either 'bulleted','numbered','labeled' or 'callout'.

delimiter::
  A Python regular expression that matches the first line of a
  list element entry. This expression can contain the named groups
  'text' (bulleted groups), 'index' and 'text' (numbered lists),
  'label' and 'text' (labeled lists).

tags::
  The `<name>` of the `[listtags-<name>]` configuration file section
  containing list markup tag definitions.  The tag entries ('list',
  'entry', 'label', 'term', 'text') map the AsciiDoc list structure to
  backend markup; see the 'listtags' sections in the AsciiDoc
  distributed backend `.conf` configuration files for examples.

Tables
~~~~~~
Table behavior and syntax is determined by `[tabledef*]` and
`[tabletags*]` configuration file sections. The user can change
existing table behavior and add new table types by editing
configuration files.  The following `[tabledef*]` section entries
generate table output markup elements:

comspec::
  The table 'comspec' tag definition.

headrow, footrow, bodyrow::
  Table header, footer and body row tag definitions. 'headrow' and
  'footrow' table definition entries default to 'bodyrow' if
  they are undefined.

headdata, footdata, bodydata::
  Table header, footer and body data tag definitions. 'headdata' and
  'footdata' table definition entries default to 'bodydata' if they
  are undefined.

paragraph::
  If the 'paragraph' tag is specified then blank lines in the cell
  data are treated as paragraph delimiters and marked up using this
  tag.

[[X4]]
Table behavior is also influenced by the following `[miscellaneous]`
configuration file entries:

pagewidth::
  This integer value is the printable width of the output media. See
  <<X69,table attributes>>.

pageunits::
  The units of width in output markup width attribute values.

.Table definition behavior
- The output markup generation is specifically designed to work with
  the HTML and CALS (DocBook) table models, but should be adaptable to
  most XML table schema.
- Table definitions can be ``mixed in'' from multiple cascading
  configuration files.
- New table definitions inherit the default table and table tags
  definitions (`[tabledef-default]` and `[tabletags-default]`) so you
  only need to override those conf file entries that require
  modification.


[[X59]]
Filters
-------
Filters are external shell commands used to process Paragraph and
DelimitedBlock content; they are specified in configuration file
Paragraph and DelimitedBlock definitions.

There's nothing special about the filters, they're just standard UNIX
filters: they read text from the standard input, process it, and write
to the standard output.

Attribute substitution is performed on the filter command prior to
execution -- attributes can be used to pass parameters from the
AsciiDoc source document to the filter.

WARNING: Filters can potentially generate unsafe output. Before
installing a filter you should verify that it can't be coerced into
generating malicious output or exposing sensitive information.

Filter Search Paths
~~~~~~~~~~~~~~~~~~~
If the filter command does not specify a directory path then
asciidoc(1) searches for the command:

- First it looks in the user's `$HOME/.asciidoc/filters` directory.
- Next the `/etc/asciidoc/filters` directory is searched.
- Then it looks in the asciidoc(1) `./filters` directory.
- Finally it relies on the executing shell to search the environment
  search path (`$PATH`).

Sub-directories are also included in the searches -- standard practice
is to install each filter in it's own sub-directory with the same name
as the filter's style definition. For example the music filter's style
name is 'music' so it's configuration and filter files are stored in
the `filters/music` directory.

Filter Configuration Files
~~~~~~~~~~~~~~~~~~~~~~~~~~
Filters are normally accompanied by a configuration file containing a
Paragraph or DelimitedBlock definition along with corresponding markup
templates.

While it is possible to create new Paragraph or DelimitedBlock
definitions the preferred way to implement a filter is to add a
<<X23,style>> to the existing Paragraph and ListingBlock definitions
(all filters shipped with AsciiDoc use this technique). The filter is
applied to the paragraph or delimited block by preceding it with an
attribute list: the first positional attribute is the style name,
remaining attributes are normally filter specific parameters.

asciidoc(1) auto-loads all `.conf` files found in the filter search
paths (see previous section).

[[X56]]
Code Filter
~~~~~~~~~~~
AsciiDoc comes with a toy filter for highlighting source code keywords
and comments.  See also the `./filters/code/code-filter-readme.txt`
file.

NOTE: This filter primarily to demonstrate how to write a filter --
it's much to simplistic to be passed off as a code syntax highlighter.
If you want a full featured multi-language highlighter use the
<<X57,Source Code Highlighter Filter>>.

[listing]
.....................................................................
.Code filter example
[code,python]
----------------------------------------------
''' A multi-line
    comment.'''
def sub_word(mo):
    ''' Single line comment.'''
    word = mo.group('word')   # Inline comment
    if word in keywords[language]:
        return quote + word + quote
    else:
        return word
----------------------------------------------
.....................................................................

Outputs:

.Code filter example
[code,python]
----------------------------------------------
''' A multi-line
    comment.'''
def sub_word(mo):
    ''' Single line comment.'''
    word = mo.group('word')   # Inline comment
    if word in keywords[language]:
        return quote + word + quote
    else:
        return word
----------------------------------------------

[[X57]]
Source Code Highlighter Filter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A
http://www.methods.co.nz/asciidoc/source-highlight-filter.html[source
code highlighter filter] can be found in the AsciiDoc distribution
`./filters` directory.

[[X58]]
Music Filter
~~~~~~~~~~~~
A http://www.methods.co.nz/asciidoc/music-filter.html[music filter] is
included in the distribution `./filters` directory. It translates
music in http://lilypond.org/[LilyPond] or
http://abcnotation.org.uk/[ABC] notation to standard Western classical
notation in the form of a trimmed PNG image which is automatically
inserted into the output document.


[[X12]]
Converting DocBook to other file formats
----------------------------------------
DocBook files are validated, parsed and translated by a combination of
applications collectively called a DocBook 'tool chain'. The function
of a tool chain is to read the DocBook markup (produced by AsciiDoc)
and transform it to a presentation format (for example HTML, PDF, HTML
Help, EPUB, DVI, PostScript, LaTeX).

A wide range of user output format requirements coupled with a choice
of available tools and stylesheets results in many valid tool chain
combinations.

[[X43]]
a2x Toolchain Wrapper
~~~~~~~~~~~~~~~~~~~~~
One of the biggest hurdles for new users is installing, configuring
and using a DocBook XML toolchain. `a2x(1)` can help -- it's a
toolchain wrapper command that will generate XHTML (chunked and
unchunked), PDF, EPUB, DVI, PS, LaTeX, man page, HTML Help and text
file outputs from an AsciiDoc text file.  `a2x(1)` does all the grunt
work associated with generating and sequencing the toolchain commands
and managing intermediate and output files.  `a2x(1)` also optionally
deploys admonition and navigation icons and a CSS stylesheet. See the
`a2x(1)` man page for more details. In addition to `asciidoc(1)` you
also need <<X40,xsltproc(1)>>, <<X13,DocBook XSL Stylesheets>> and
optionally: <<X31,dblatex>> or <<X14,FOP>> (if to generate PDF);
`w3m(1)` or `lynx(1)` (if to generate text).

The following examples generate `doc/source-highlight-filter.pdf` from
the AsciiDoc `doc/source-highlight-filter.txt` source file. The first
example uses `dblatex(1)` (the default PDF generator) the second
example forces FOP to be used:

  $ a2x -f pdf doc/source-highlight-filter.txt
  $ a2x -f pdf --fop doc/source-highlight-filter.txt

See the `a2x(1)` man page for details.

TIP: Use the `--verbose` command-line option to view executed
toolchain commands.

HTML generation
~~~~~~~~~~~~~~~
AsciiDoc produces nicely styled HTML directly without requiring a
DocBook toolchain but there are also advantages in going the DocBook
route:

- HTML from DocBook includes automatically generated indexes, tables
  of contents, footnotes, lists of figures and tables.
- DocBook toolchains can also (optionally) generate separate (chunked)
  linked HTML pages for each document section.
- Toolchain processing performs link and document validity checks.
- If the DocBook 'lang' attribute is set then things like table of
  contents, figure and table captions and admonition captions will be
  output in the specified language (setting the AsciiDoc 'lang'
  attribute sets the DocBook 'lang' attribute).

On the other hand, HTML output directly from AsciiDoc is much faster,
is easily customized and can be used in situations where there is no
suitable DocBook toolchain (see the
http://www.methods.co.nz/asciidoc/[AsciiDoc website] for example).

PDF generation
~~~~~~~~~~~~~~
There are two commonly used tools to generate PDFs from DocBook,
<<X31,dblatex>> and <<X14,FOP>>.

.dblatex or FOP?
- 'dblatex' is easier to install, there's zero configuration
  required and no Java VM to install -- it just works out of the box.
- 'dblatex' source code highlighting and numbering is superb.
- 'dblatex' is easier to use as it converts DocBook directly to PDF
  whereas before using 'FOP' you have to convert DocBook to XML-FO
  using <<X13,DocBook XSL Stylesheets>>.
- 'FOP' is more feature complete (for example, callouts are processed
  inside literal layouts) and arguably produces nicer looking output.

HTML Help generation
~~~~~~~~~~~~~~~~~~~~
. Convert DocBook XML documents to HTML Help compiler source files
  using <<X13,DocBook XSL Stylesheets>> and <<X40,xsltproc(1)>>.
. Convert the HTML Help source (`.hhp` and `.html`) files to HTML Help
  (`.chm`) files using the <<X67,Microsoft HTML Help Compiler>>.

Toolchain components summary
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc::
    Converts AsciiDoc (`.txt`) files to DocBook XML (`.xml`) files.

[[X13]]http://docbook.sourceforge.net/projects/xsl/[DocBook XSL Stylesheets]::
  These are a set of XSL stylesheets containing rules for converting
  DocBook XML documents to HTML, XSL-FO, manpage and HTML Help files.
  The stylesheets are used in conjunction with an XML parser such as
  <<X40,xsltproc(1)>>.

[[X40]]http://www.xmlsoft.org[xsltproc]::
  An XML parser for applying XSLT stylesheets (in our case the
  <<X13,DocBook XSL Stylesheets>>) to XML documents.

[[X31]]http://dblatex.sourceforge.net/[dblatex]::
  Generates PDF, DVI, PostScript and LaTeX formats directly from
  DocBook source via the intermediate LaTeX typesetting language --
  uses <<X13,DocBook XSL Stylesheets>>, <<X40,xsltproc(1)>> and
  `latex(1)`.

[[X14]]http://xml.apache.org/fop/[FOP]::
  The Apache Formatting Objects Processor converts XSL-FO (`.fo`)
  files to PDF files.  The XSL-FO files are generated from DocBook
  source files using <<X13,DocBook XSL Stylesheets>> and
  <<X40,xsltproc(1)>>.

[[X67]]Microsoft Help Compiler::
  The Microsoft HTML Help Compiler (`hhc.exe`) is a command-line tool
  that converts HTML Help source files to a single HTML Help (`.chm`)
  file. It runs on MS Windows platforms and can be downloaded from
  http://www.microsoft.com.

AsciiDoc dblatex configuration files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The AsciiDoc distribution `./dblatex` directory contains
`asciidoc-dblatex.xsl` (customized XSL parameter settings) and
`asciidoc-dblatex.sty` (customized LaTeX settings). These are examples
of optional <<X31,dblatex>> output customization and are used by
<<X43,a2x(1)>>.

AsciiDoc DocBook XSL Stylesheets drivers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You will have noticed that the distributed HTML and HTML Help
documentation files (for example `./doc/asciidoc.html`) are not the
plain outputs produced using the default 'DocBook XSL Stylesheets'
configuration.  This is because they have been processed using
customized DocBook XSL Stylesheets along with (in the case of HTML
outputs) the custom `./stylesheets/docbook.css` CSS stylesheet.

You'll find the customized DocBook XSL drivers along with additional
documentation in the distribution `./docbook-xsl` directory. The
examples that follow are executed from the distribution documentation
(`./doc`) directory. These drivers are required by <<X43,a2x(1)>>.

`common.xsl`::
    Shared driver parameters.  This file is not used directly but is
    included in all the following drivers.

`chunked.xsl`::
    Generate chunked XHTML (separate HTML pages for each document
    section) in the `./doc/chunked` directory. For example:

    $ python ../asciidoc.py -b docbook asciidoc.txt
    $ xsltproc --nonet ../docbook-xsl/chunked.xsl asciidoc.xml

`epub.xsl`::
    Used by <<X43,a2x(1)>> to generate EPUB formatted documents.

`fo.xsl`::
    Generate XSL Formatting Object (`.fo`) files for subsequent PDF
    file generation using FOP. For example:

    $ python ../asciidoc.py -b docbook article.txt
    $ xsltproc --nonet ../docbook-xsl/fo.xsl article.xml > article.fo
    $ fop article.fo article.pdf

`htmlhelp.xsl`::
    Generate Microsoft HTML Help source files for the MS HTML Help
    Compiler in the `./doc/htmlhelp` directory. This example is run on
    MS Windows from a Cygwin shell prompt:

    $ python ../asciidoc.py -b docbook asciidoc.txt
    $ xsltproc --nonet ../docbook-xsl/htmlhelp.xsl asciidoc.xml
    $ c:/Program\ Files/HTML\ Help\ Workshop/hhc.exe htmlhelp.hhp

`manpage.xsl`::
    Generate a `roff(1)` format UNIX man page from a DocBook XML
    'refentry' document. This example generates an `asciidoc.1` man
    page file:

    $ python ../asciidoc.py -d manpage -b docbook asciidoc.1.txt
    $ xsltproc --nonet ../docbook-xsl/manpage.xsl asciidoc.1.xml

`xhtml.xsl`::
    Convert a DocBook XML file to a single XHTML file. For example:

    $ python ../asciidoc.py -b docbook asciidoc.txt
    $ xsltproc --nonet ../docbook-xsl/xhtml.xsl asciidoc.xml > asciidoc.html

If you want to see how the complete documentation set is processed
take a look at the A-A-P script `./doc/main.aap`.


Generating Plain Text Files
---------------------------
AsciiDoc does not have a text backend (for most purposes AsciiDoc
source text is fine), however you can convert AsciiDoc text files to
formatted text using the AsciiDoc <<X43,a2x(1)>> toolchain wrapper
utility.


XML and Character Sets
----------------------
The default XML character set `UTF-8` is used when AsciiDoc generates
DocBook files but this can be changed by setting the `xmldecl` entry
in the `[attributes]` section of the `docbook.conf` file or by
composing your own configuration file `[header]` section).

TIP: If you get an 'undefined entity' error when processing DocBook
files you'll may find that you've used an undefined HTML character
entity.  An easy (although inelegant) fix is to use the character's
character code instead of its symbolic name (for example use `&#160;`
instead of `&nbsp;`).

If your system has been configured with an XML catalog you may find a
number of entity sets are already automatically included.

PDF Fonts
~~~~~~~~~
The Adobe PDF Specification states that the following 14 fonts should
be available to every PDF reader: Helvetica (normal, bold, italic,
bold italic), Times (normal, bold, italic, bold italic), Courier
(normal, bold, italic, bold italic), Symbol and ZapfDingbats.
Non-standard fonts should be embedded in the distributed document.


[[X36]]
Help Commands
-------------
The asciidoc(1) command has a `--help` option which prints help topics
to stdout. The default topic summarizes asciidoc(1) usage:

  $ asciidoc --help

To print a list of help topics:

  $ asciidoc --help=topics

To print a help topic specify the topic name as a command argument.
Help topic names can be shortened so long as they are not ambiguous.
Examples:

  $ asciidoc --help=manpage
  $ asciidoc -hm              # Short version of previous example.
  $ asciidoc --help=syntax
  $ asciidoc -hs              # Short version of previous example.

Customizing Help
~~~~~~~~~~~~~~~~
To change, delete or add your own help topics edit a help
configuration file.  The help file name `help-<lang>.conf` is based on
the setting of the `lang` attribute, it defaults to `help.conf`
(English).  The <<X27,help file location>> will depend on whether you
want the topics to apply to all users or just the current user.

The help topic files have the same named section format as other
<<X7,configuration files>>. The `help.conf` files are stored in the
same locations and loaded in the same order as other configuration
files.

When the `--help` command-line option is specified AsciiDoc loads the
appropriate help files and then prints the contents of the section
whose name matches the help topic name.  If a topic name is not
specified `default` is used. You don't need to specify the whole help
topic name on the command-line, just enough letters to ensure it's not
ambiguous. If a matching help file section is not found a list of
available topics is printed.


Tips and Tricks
---------------

Know Your Editor
~~~~~~~~~~~~~~~~
Writing AsciiDoc documents will be a whole lot more pleasant if you
know your favorite text editor. Learn how to indent and reformat text
blocks, paragraphs, lists and sentences. <<X20,Tips for 'vim' users>>
follow.

[[X20]]
Vim Commands for Formatting AsciiDoc
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Text Wrap Paragraphs
^^^^^^^^^^^^^^^^^^^^
Use the vim `:gq` command to reformat paragraphs. Setting the
'textwidth' sets the right text wrap margin; for example:

  :set textwidth=70

To reformat a paragraph:

1. Position the cursor at the start of the paragraph.
2. Type `gq}`.

Execute `:help gq` command to read about the vim gq command.

[TIP]
=====================================================================
- Assign the `gq}` command to the Q key with the `nnoremap Q gq}`
  command or put it in your `~/.vimrc` file to so it's always
  available (see the <<X61, Example `~/.vimrc` file>>).
- Put `set` commands in your `~/.vimrc` file so you don't have to
  enter them manually.
- The Vim website (http://www.vim.org) has a wealth of resources,
  including scripts for automated spell checking and ASCII Art
  drawing.
=====================================================================

Format Lists
^^^^^^^^^^^^
The `gq` command can also be used to format bulleted, numbered and
callout lists. First you need to set the `comments`, `formatoptions`
and `formatlistpat` (see the <<X61, Example `~/.vimrc` file>>).

Now you can format simple lists that use dash, asterisk, period and
plus bullets along with numbered ordered lists:

1. Position the cursor at the start of the list.
2. Type `gq}`.

Indent Paragraphs
^^^^^^^^^^^^^^^^^
Indent whole paragraphs by indenting the fist line with the desired
indent and then executing the `gq}` command.

[[X61]]
Example `~/.vimrc` File
^^^^^^^^^^^^^^^^^^^^^^^
---------------------------------------------------------------------
" Show tabs and trailing characters.
set listchars=tab:»·,trail:·
set list

" Don't highlight searched text.
highlight clear Search

" Don't move to matched text while search pattern is being entered.
set noincsearch

" Reformat paragraphs and list.
nnoremap R gq}

" Delete trailing white space and Dos-returns and to expand tabs to spaces.
nnoremap S :set et<CR>:retab!<CR>:%s/[\r \t]\+$//<CR>

autocmd BufRead,BufNewFile *.txt,README,TODO,CHANGELOG,NOTES
        \ setlocal autoindent expandtab tabstop=8 softtabstop=2 shiftwidth=2 filetype=asciidoc
        \ textwidth=70 wrap formatoptions=tcqn
        \ formatlistpat=^\\s*\\d\\+\\.\\s\\+\\\\|^\\s*<\\d\\+>\\s\\+\\\\|^\\s*[a-zA-Z.]\\.\\s\\+\\\\|^\\s*[ivxIVX]\\+\\.\\s\\+
        \ comments=s1:/*,ex:*/,://,b:#,:%,:XCOMM,fb:-,fb:*,fb:+,fb:.,fb:>
---------------------------------------------------------------------

Troubleshooting
~~~~~~~~~~~~~~~
- The asciidoc(1) `-v` (`--verbose`) command-line option displays the
  order of configuration file loading and warns of potential
  configuration file problems.
- Not all valid AsciiDoc documents produce valid backend markup. Read
  the <<X5,AsciiDoc Backends>> section if AsciiDoc output is rejected
  as non-conformant by a backend processor.

Gotchas
~~~~~~~
Incorrect character encoding::
    If you get an error message like `'UTF-8' codec can't decode ...`
    then you source file contains invalid UTF-8 characters -- set the
    AsciiDoc <<X54,encoding attribute>> for the correct character set
    (typically ISO-8859-1 (Latin-1) for European languages).

Invalid output::
    AsciiDoc attempts to validate the input AsciiDoc source but makes
    no attempt to validate the output markup, it leaves that to
    external tools such as `xmllint(1)` (integrated into `a2x(1)`).
    Backend validation cannot be hardcoded into AsciiDoc because
    backends are dynamically configured. The following example
    generates valid HTML but invalid DocBook (the DocBook `literal`
    element cannot contain an `emphasis` element):

    +monospaced text with an _emphasized_ word+

Misinterpreted text formatting::
    You can suppress markup expansion by placing a backslash character
    immediately in front of the element. The following example
    suppresses inline monospaced formatting:

    \+1 for C++.

Overlapping text formatting::
    Overlapping text formatting will generate illegal overlapping
    markup tags which will result in downstream XML parsing errors.
    Here's an example:

    Some *strong markup _that overlaps* emphasized markup_.

Ambiguous underlines::
    A DelimitedBlock can immediately follow paragraph without an
    intervening blank line, but be careful, a single line paragraph
    underline may be misinterpreted as a section title underline
    resulting in a ``closing block delimiter expected'' error.

Ambiguous ordered list items::
    Lines beginning with numbers at the end of sentences will be
    interpreted as ordered list items.  The following example
    (incorrectly) begins a new list with item number 1999:

    He was last sighted in
    1999. Since then things have moved on.
+
The 'list item out of sequence' warning makes it unlikely that this
problem will go unnoticed.

Special characters in attribute values::
    Special character substitution precedes attribute substitution so
    if attribute values contain special characters you may, depending
    on the substitution context, need to escape the special characters
    yourself. For example:

    $ asciidoc -a 'corpname=Bill &amp; Ben Inc.' mydoc.txt

Macro attribute lists::
    If named attribute list entries are present then all string
    attribute values must be quoted.  For example:

    ["Desktop screenshot",width=32]

[[X90]]
Combining separate documents
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You have a number of stand-alone AsciiDoc documents that you want to
process as a single document. Simply processing them with a series of
`include` macros won't work because the documents contain (level 0)
document titles.  The solution is to create a top level wrapper
document and use the `leveloffset` attribute to push them all down one
level. For example:

---------------------------------------------------------------------
Combined Document Title
_______________________

:leveloffset: 1

\include::document1.txt[]

\include::document2.txt[]

\include::document3.txt[]
---------------------------------------------------------------------

The document titles in the included documents will now be processed as
level 1 section titles, level 1 sections as level 2 sections and so
on.

- Put a blank line between the `include` macro lines to ensure the
  title of the included document is not seen as part of the last
  paragraph of the previous document.
- You won't want document Headers (Author and Revision lines) in the
  included files -- conditionally exclude them if they are necessary
  for stand-alone processing.

Processing document sections separately
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You have divided your AsciiDoc document into separate files (one per
top level section) which are combined and processed with the following
top level document:

---------------------------------------------------------------------
Combined Document Title
=======================
Joe Bloggs
v1.0, 12-Aug-03

\include::section1.txt[]

\include::section2.txt[]

\include::section3.txt[]
---------------------------------------------------------------------

You also want to process the section files as separate documents.
This is easy because asciidoc(1) will quite happily process
`section1.txt`, `section2.txt` and `section3.txt` separately -- the
resulting output documents contain the section but have no document
title.

Processing document snippets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Use the `-s` (`--no-header-footer`) command-line option to suppress
header and footer output, this is useful if the processed output is to
be included in another file. For example:

  $ asciidoc -sb docbook section1.txt

asciidoc(1) can be used as a filter, so you can pipe chunks of text
through it. For example:

  $ echo 'Hello *World!*' | asciidoc -s -
  <div class="paragraph"><p>Hello <strong>World!</strong></p></div>

Badges in HTML page footers
~~~~~~~~~~~~~~~~~~~~~~~~~~~
See the `[footer]` section in the AsciiDoc distribution `xhtml11.conf`
configuration file.

Pretty printing AsciiDoc output
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If the indentation and layout of the asciidoc(1) output is not to your
liking you can:

1. Change the indentation and layout of configuration file markup
   template sections. The `{empty}` glossary entry is useful for
   outputting trailing blank lines in markup templates.

2. Use Dave Raggett's http://tidy.sourceforge.net/[HTML Tidy] program
   to tidy asciidoc(1) output. Example:

   $ asciidoc -b docbook -o - mydoc.txt | tidy -indent -xml >mydoc.xml

3. Use the `xmllint(1)` format option. Example:

   $ xmllint --format mydoc.xml

Supporting minor DocBook DTD variations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The conditional inclusion of DocBook SGML markup at the end of the
distribution `docbook.conf` file illustrates how to support minor DTD
variations. The included sections override corresponding entries from
preceding sections.

Creating stand-alone HTML documents
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you've ever tried to send someone an HTML document that includes
stylesheets and images you'll know that it's not as straight-forward
as exchanging a single file.  AsciiDoc has options to create
stand-alone documents containing embedded images, stylesheets and
scripts.  The following AsciiDoc command creates a single file
containing <<X66,embedded images>>, CSS stylesheets, and JavaScript
(for table of contents and footnotes):

  $ asciidoc -a data-uri -a icons -a toc -a max-width=55em article.txt

You can view the HTML file here:
http://www.methods.co.nz/asciidoc/article-standalone.html

Shipping stand-alone AsciiDoc source
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Reproducing presentation documents from someone else's source has one
major problem: unless your configuration files are the same as the
creator's you won't get the same output.

The solution is to create a single backend specific configuration file
using the asciidoc(1) `-c` (`--dump-conf`) command-line option. You
then ship this file along with the AsciiDoc source document plus the
`asciidoc.py` script. The only end user requirement is that they have
Python installed (and of course that they consider you a trusted
source). This example creates a composite HTML configuration
file for `mydoc.txt`:

  $ asciidoc -cb xhtml11 mydoc.txt > mydoc-xhtml11.conf

Ship `mydoc.txt`, `mydoc-html.conf`, and `asciidoc.py`. With
these three files (and a Python interpreter) the recipient can
regenerate the HMTL output:

  $ ./asciidoc.py -eb xhtml11 mydoc.txt

The `-e` (`--no-conf`) option excludes the use of implicit
configuration files, ensuring that only entries from the
`mydoc-html.conf` configuration are used.

Inserting blank space
~~~~~~~~~~~~~~~~~~~~~
Adjust your style sheets to add the correct separation between block
elements. Inserting blank paragraphs containing a single non-breaking
space character `{nbsp}` works but is an ad hoc solution compared
to using style sheets.

Closing open sections
~~~~~~~~~~~~~~~~~~~~~
You can close off section tags up to level `N` by calling the
`eval::[Section.setlevel(N)]` system macro. This is useful if you
want to include a section composed of raw markup. The following
example includes a DocBook glossary division at the top section level
(level 0):

---------------------------------------------------------------------
\ifdef::backend-docbook[]

\eval::[Section.setlevel(0)]

+++++++++++++++++++++++++++++++
<glossary>
  <title>Glossary</title>
  <glossdiv>
  ...
  </glossdiv>
</glossary>
+++++++++++++++++++++++++++++++
\endif::backend-docbook[]
---------------------------------------------------------------------

Validating output files
~~~~~~~~~~~~~~~~~~~~~~~
Use `xmllint(1)` to check the AsciiDoc generated markup is both well
formed and valid. Here are some examples:

  $ xmllint --nonet --noout --valid docbook-file.xml
  $ xmllint --nonet --noout --valid xhtml11-file.html
  $ xmllint --nonet --noout --valid --html html4-file.html

The `--valid` option checks the file is valid against the document
type's DTD, if the DTD is not installed in your system's catalog then
it will be fetched from its Internet location. If you omit the
`--valid` option the document will only be checked that it is well
formed.


:numbered!:

[glossary]
Glossary
--------
[glossary]
[[X8]] Block element::
    An AsciiDoc block element is a document entity composed of one or
    more whole lines of text.

[[X34]] Inline element::
    AsciiDoc inline elements occur within block element textual
    content, they perform formatting and substitution tasks.

Formal element::
    An AsciiDoc block element that has a BlockTitle. Formal elements
    are normally listed in front or back matter, for example lists of
    tables, examples and figures.

Verbatim element::
    The word verbatim indicates that white space and line breaks in
    the source document are to be preserved in the output document.


[appendix]
Migration Notes
---------------
[[X53]]
Version 7 to version 8
~~~~~~~~~~~~~~~~~~~~~~
- A new set of quotes has been introduced which may match inline text
  in existing documents -- if they do you'll need to escape the
  matched text with backslashes.
- The index entry inline macro syntax has changed -- if your documents
  include indexes you may need to edit them.
- Replaced a2x(1) `--no-icons` and `--no-copy` options with their
  negated equivalents: `--icons` and `--copy` respectively. The
  default behavior has also changed -- the use of icons and copying of
  icon and CSS files must be specified explicitly with the `--icons`
  and `--copy` options.

The rationale for the changes can be found in the AsciiDoc
`CHANGELOG`.

NOTE: If you want to disable unconstrained quotes, the new alternative
constrained quotes syntax and the new index entry syntax then you can
define the attribute `asciidoc7compatible` (for example by using the
`-a asciidoc7compatible` command-line option).

[[X38]]
[appendix]
Packager Notes
--------------
Read the `README` and `INSTALL` files (in the distribution root
directory) for install prerequisites and procedures.  The distribution
`Makefile.in` (used by `configure` to generate the `Makefile`) is the
canonical installation procedure.


[[X39]]
[appendix]
AsciiDoc Safe Mode
-------------------
AsciiDoc 'safe mode' skips potentially dangerous scripted sections in
AsciiDoc source files by inhibiting the execution of arbitrary code or
the inclusion of arbitrary files.

The safe mode is disabled by default, it can be enabled with the
asciidoc(1) `--safe` command-line option.

.Safe mode constraints
- `eval`, `sys` and `sys2` executable attributes and block macros are
  not executed.
- `include::<filename>[]` and `include1::<filename>[]` block macro
  files must reside inside the parent file's directory.
- `{include:<filename>}` executable attribute files must reside
  inside the source document directory.
- Passthrough Blocks are dropped.

[WARNING]
=====================================================================
The safe mode is not designed to protect against unsafe AsciiDoc
configuration files. Be especially careful when:

1. Implementing filters.
2. Implementing elements that don't escape special characters.
3. Accepting configuration files from untrusted sources.
=====================================================================


[appendix]
Using AsciiDoc with non-English Languages
-----------------------------------------
AsciiDoc can process UTF-8 character sets but there are some things
you need to be aware of:

- If you are generating output documents using a DocBook toolchain
  then you should set the AsciiDoc `lang` attribute to the appropriate
  language (it defaults to `en` (English)). This will ensure things
  like table of contents, figure and table captions and admonition
  captions are output in the specified language.  For example:

  $ a2x -a lang=es doc/article.txt

- If you are outputting HTML directly from asciidoc(1) you'll
  need to set the various `*_caption` attributes to match your target
  language (see the list of captions and titles in the `[attributes]`
  section of the default `asciidoc.conf` file). The easiest way is to
  create a language `.conf` file (see the AsciiDoc's `lang-en.conf`
  file).
+
NOTE: You still use the 'NOTE', 'CAUTION', 'TIP', 'WARNING',
'IMPORTANT' captions in the AsciiDoc source, they get translated in
the HTML output file.

- asciidoc(1) automatically loads configuration files named like
  `lang-<lang>.conf` where `<lang>` is a two letter language code that
  matches the current AsciiDoc `lang` attribute. See also
  <<X27,Configuration File Names and Locations>>.

- Some character sets display double-width characters (for example
  Japanese). As far as <<X17,title underlines>> are concerned they
  should be treated as single character.  If you think this looks
  untidy so you may prefer to use the <<X46,single line title>>
  format.


[appendix]
Vim Syntax Highlighter
----------------------
Syntax highlighting is incredibly useful, in addition to making
reading AsciiDoc documents much easier syntax highlighting also helps
you catch AsciiDoc syntax errors as you write your documents.

The AsciiDoc `./vim/` distribution directory contains Vim syntax
highlighter and filetype detection scripts for AsciiDoc.  Syntax
highlighting makes it much easier to spot AsciiDoc syntax errors.

If Vim is installed on your system the AsciiDoc installer
(`install.sh`) will automatically install the vim scripts in the Vim
global configuration directory (`/etc/vim`).

You can also turn on syntax highlighting by adding the following line
to the end of you AsciiDoc source files:

  // vim: set syntax=asciidoc:

NOTE: Dag Wieers has implemented an alternative Vim syntax file for
AsciiDoc which can be found here
http://svn.rpmforge.net/svn/trunk/tools/asciidoc-vim/.

NOTE: Emacs users: The http://xpt.sourceforge.net/[*Nix Power Tools
project] has released an
http://xpt.sourceforge.net/tools/doc-mode/[AsciiDoc syntax highlighter
for emacs].

Limitations
~~~~~~~~~~~
The current implementation does a reasonable job but on occasions gets
things wrong:

- Nested quoted text formatting is highlighted according to the outer
  format.
- If a closing Example Block delimiter is sometimes mistaken for a
  title underline. A workaround is to insert a blank line before the
  closing delimiter.
- Lines within a paragraph starting with equals characters may be
  highlighted as single-line titles.
- Lines within a paragraph beginning with a period may be highlighted
  as block titles.


[[X74]]
[appendix]
Attribute Options
-----------------
Here is the list of predefined <<X75,attribute list options>>:


[cols="2e,2,2,5",frame="topbot",options="header"]
|====================================================================
|Option|Backends|AsciiDoc Elements|Description

|autowidth |xhtml11,html4 |table|
The column widths are determined by the browser, not the AsciiDoc
'cols' attribute. If there is no 'width' attribute the table width is
also left up to the browser.

|breakable, unbreakable |docbook (XSL/FO) |table, example, block image|
The 'breakable' options allows block elements to break across page
boundaries; 'unbreakable' attempts to keep the block element together
on a single page. If neither option is specified the default XSL
stylesheet behavior prevails.

|compact |docbook, xhtml11 |bulleted list, numbered list|
Minimizes vertical space in the list

|footer |docbook, xhtml11, html4 |table|
The last row of the table is rendered as a footer.

|header |docbook, xhtml11, html4 |table|
The first row of the table is rendered as a header.

|pgwide |docbook (XSL/FO) |table, block image, horizontal labeled list|
Specifies that the element should be rendered across the full text
width of the page irrespective of the current indentation.

|strong |xhtml11,html4 |labeled lists|
Emboldens label text.
|====================================================================


[[X82]]
[appendix]
Diagnostics
-----------
The `asciidoc(1)` `--verbose` command-line option prints additional
information to stderr: files processed, filters processed, warnings,
system attribute evaluation.

A special attribute named 'trace' controls the output of diagnostic
information. If the 'trace' attribute is defined then
element-by-element diagnostic messages detailing output markup
generation are printed to stderr. The 'trace' attribute can be set on
the command-line or from within the document using <<X18,Attribute
Entries>> (the latter allows tracing to be confined to specific
portions of the document).

- Trace messages consist of a descriptive name followed by the related
  markup.
- The trace message is only printed if the 'trace' attribute value
  matches the start of the trace name. The 'trace' attribute value can
  be any Python regular expression.
- A blank trace value matches all trace names and all trace messages
  will be printed (this can result in large amounts of output if
  applied to the whole document).
- In the case of inline substitutions:
  * The text before and after the substitution are printed delineated
    by `<<<` and `>>>` delimiters.
  * The message is only printed if a substitution is made.
  * The 'subs' trace value is an alias for all inline substitutions.

Command-line examples:

. Trace the entire document.

  $ asciidoc -a trace mydoc.txt

. Trace messages whose names start with `quotes` or `macros`:

  $ asciidoc -a 'trace=quotes|macros'  mydoc.txt

. Print the first line of all trace messages:

  $ asciidoc -a trace mydoc.txt 2>&1 | grep ^TRACE:

Attribute Entry examples:

. Begin printing all trace messages:

  :trace:

. Print only matched trace messages:

  :trace: quotes|macros

. Turn trace messages off:

  :trace!:


[[X88]]
[appendix]
Backend Attributes
------------------
This table contains a list of optional attributes that influence the
generated outputs.

[cols="1e,1,5a",frame="topbot",options="header"]
|====================================================================
|Name |Backends |Description

|badges |xhtml11 |
Link badges ('XHTML 1.1', 'CSS' and 'Get Firefox!') in document
footers. By default badges are omitted ('badges' is undefined).

NOTE: The path names of images, icons and scripts are relative path
names to the output document not the source document.

|data-uri |xhtml11 |
Embed images using the <<X66,data: uri scheme>>.

|disable-javascript |xhtml11 |
If the `disable-javascript` attribute is defined the `asciidoc.js`
JavaScript is not embedded or linked to the output document.  By
default AsciiDoc automatically embeds or links the `asciidoc.js`
JavaScript to the 'xhtml11' output document. The script dynamically
generates <<X91,table of contents>> and <<X92,footnotes>>.

|docinfo |docbook |
The <<X87,document information file>> will be included in the DocBook
output if the `docinfo` attribute is defined.

|[[X54]]encoding |html4, xhtml11, docbook |
Set the input and output document character set encoding. For example
the `--attribute encoding=ISO-8859-1` command-line option will set the
character set encoding to `ISO-8859-1`.

- The default encoding is UTF-8.
- This attribute specifies the character set in the output document.
- The encoding name must correspond to a Python codec name or alias.
- The 'encoding' attribute can be set using an AttributeEntry inside
  the document header but it must come at the start of the document
  before the document title. For example:

  :encoding: ISO-8859-1

|[[X45]]icons |xhtml11 |
Link admonition paragraph and admonition block icon images and badge
images. By default 'icons' is undefined and text is used in place of
icon images.

|[[X44]]iconsdir |html4, xhtml11, docbook |
The name of the directory containing linked admonition and navigation
icons. Defaults to `./images/icons`.

|imagesdir |html4, xhtml11, docbook |
If this attribute is defined it is prepended to the target image file
name paths in inline and block image macros.

|linkcss |xhtml11 |
Link CSS stylesheets and JavaScripts (see the 'stylesdir' and
'scriptsdir' attributes below). By default 'linkcss' is undefined in
which case stylesheets and scripts are automatically embedded in the
output document.

|max-width |xhtml11 |
Set the document maximum display width (sets the 'body' element CSS
'max-width' property). 'max-width' definition must precede the
document header.

|numbered |html4, xhtml11, docbook (XSL Stylesheets) |
Adds section numbers to section titles. The 'docbook' backend ignores
'numbered' attribute entries after the document header.

|quirks |xhtml11 |
Use the `xhtml11-quirks.css` stylesheet to work around IE6 browser
incompatibilities (this is the default behavior).

|revremark |docbook |
A short summary of changes in this document revision. Must be defined
prior to the first document section. The document also needs to be
dated to output this attribute.

|scriptsdir |xhtml11 |
The name of the directory containing linked JavaScripts. Defaults to
`.` (the same directory as the linking document).

|sgml |docbook |
The `--backend=docbook` command-line option produces DocBook XML.  You
can produce the older DocBook SGML format using the `--attribute sgml`
command-line option.

|stylesdir |xhtml11 |
The name of the directory containing linked stylesheets. Defaults to
`.` (the same directory as the linking document).

|stylesheet |xhtml11 |
The file name of an optional additional CSS stylesheet. If you are
embedding the stylesheet specify the actual file name; if you are
linking CSS specify the file name relative to the directory specified
by the 'stylesdir' attribute.

|theme |xhtml11 |
Use alternative stylesheets (see <<X35,Stylesheets>>).

|[[X91]]toc |xhtml11, docbook (XSL Stylesheets) |
Adds a table of contents to the start of an article or book document.

NOTE: The `toc` attribute must be specified using the `--attribute`
command-line option. If you define the `toc` attribute in a custom
configuration file it won't be recognized because the conditionally
included header code will have already been processed.

*xhtml11 backend*

- JavaScript needs to be enabled in your browser.
- The following example generates a numbered table of contents using a
  JavaScript embedded in the `mydoc.html` output document (to link the
  script to the output document use the 'linkcss' and 'scriptsdir'
  attributes):

  $ asciidoc -a toc -a numbered mydoc.txt

|toc-title |xhtml11 |
Sets the table of contents title (defaults to 'Table of Contents').

|toclevels |xhtml11 |
Sets the number of title levels (1..4) reported in the table of
contents (see the 'toc' attribute above). Defaults to 2 and must be
used with the 'toc' attribute. Example usage:

  $ asciidoc -a toc -a toclevels=3 doc/asciidoc.txt

|====================================================================

