AsciiDoc User Guide
===================
Stuart Rackham <srackham@gmail.com>
:Author Initials: SJR
AsciiDoc is a text document format for writing short documents,
articles, 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, FAQ, 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, 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.
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 markup supports standard DocBook frontmatter and backmatter
<<X16,special sections>> (dedication, preface, bibliography, glossary,
index, colophon) plus footnotes and index entries.
.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.
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.
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, DVI, PostScript, LaTeX, roff
(the native man page format), HTMLHelp, JavaHelp and text.
- The `--backend=docbook` command-line option produces DocBook XML.
You can produce the older DocBook SGML format using the
`--attribute sgml` command-line option.
- Use the optional <<X54,`encoding`>> attribute to set the character
set encoding.
- Use the optional `imagesdir` attribute to prepend to the target file
name paths in image inline and block macros. Defaults to a blank
string.
- The AsciiDoc 'Preamble' element generates a DocBook book 'preface'
element although it's more usual to use an explicit 'Preface'
special section (see the `./doc/book.txt` example book).
[[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):
numbered::
Adds section numbers to section titles.
toc::
Adds a table of contents to the start of the document.
- JavaScript needs to be enabled in your browser for this to work.
- By default AsciiDoc automatically embeds the required `toc.js`
JavaScript in the output document -- use the 'linkcss' attribute
to link the script.
- The following example generates a numbered table of contents by
embedding the `toc.js` script 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
toclevels::
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
toc_title::
Sets the table of contents title (defaults to 'Table of Contents').
linkcss::
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.
stylesdir::
The name of the directory containing linked stylesheets. Defaults to
`.` (the same directory as the linking document).
scriptsdir::
The name of the directory containing linked JavaScripts. Defaults to
`.` (the same directory as the linking document).
[[X45]]
icons::
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::
The name of the directory containing linked admonition and
navigation icons. Defaults to `./images/icons`.
imagesdir::
This attribute is prepended to the target image file name paths in
image inline and block macros. Defaults to a blank string.
theme::
Use alternative stylesheets (see <<X35,Stylesheets>>).
badges::
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 to the
output document not the source document.
[[X54]]
encoding::
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
quirks::
Use the `xhtml11-quirks.css` stylesheet to work around IE6 browser
incompatibilities (this is the default behavior).
data-uri::
Embed images referenced by 'image' macros using the <<X66,data: uri
scheme>>.
[[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 and 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`.
html4
~~~~~
This backend generates plain (unstyled) HTML 4.01 Transitional markup.
linuxdoc
~~~~~~~~
WARNING: The AsciiDoc linuxdoc backend is still distributed but is no
longer being actively developed or tested with new AsciiDoc releases
(the last supported release was AsciiDoc 6.0.3).
- Tables are not supported.
- Images are not supported.
- Callouts are not supported.
- Horizontal labeled lists are not supported.
- Only article document types are allowed.
- The Abstract section can consist only of a single paragraph.
- An AsciiDoc Preamble is not allowed.
- The LinuxDoc output format does not support multiple labels per
labeled list item although LinuxDoc conversion programs generally
output all the labels with a warning.
- Don't apply character formatting to the `link` macro attributes,
LinuxDoc does not allow displayed link text to be formatted.
The default output file name extension is `.sgml`.
latex
~~~~~
An experimental LaTeX backend has been written for AsciiDoc by
Benjamin Klum. A tutorial `./doc/latex-backend.html` is included in
the AsciiDoc distribution which can also be viewed at
http://www.methods.co.nz/asciidoc/latex-backend.html.
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
footnote:[This is a rough structural guide, not a rigorous syntax
definition] as follows:
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 ::= (ItemLabel+,ListItem)+
ListItem ::= (ItemText,(List|ListParagraph|ListContinuation)*)
Table ::= (Ruler,TableHeader?,TableBody,TableFooter?)
TableHeader ::= (TableRow+,TableUnderline)
TableFooter ::= (TableRow+,TableUnderline)
TableBody ::= (TableRow+,TableUnderline)
TableRow ::= (TableData+)
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 is optional but must start on the first line of the
document and must begin with a document <<X17,title>>. Optional Author
and Revision lines immediately follow the title. The header can be
preceded by a CommentBlock or comment lines.
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.
The optional document header revision line should immediately follow
the author line. The revision line can be one of two formats:
. An alphanumeric document revision number followed by a date:
* The revision number and date must be separated by a comma.
* The revision number is optional but must contain at least one
numeric character.
* Any non-numeric characters preceding the first numeric character
will be dropped.
. An RCS/CSV/SVN $Id$ marker.
The document heading is separated from the remainder of the document
by one or more blank lines.
Here's an example AsciiDoc document header:
Writing Documentation using AsciiDoc
====================================
Stuart Rackham <srackham@gmail.com>
v2.0, February 2003
You can override or set header parameters by passing 'revision',
'data', 'email', 'author', 'authorinitials', 'firstname' and
'lastname' attributes using the asciidoc(1) `-a` (`--attribute`)
command-line option. For example:
$ asciidoc -a date=2004/07/27 article.txt
Attributes can also be added to the header for substitution in the
header template with <<X18,Attribute Entry>> elements.
Preamble
~~~~~~~~
The Preamble is an optional untitled section body between the document
Header and the first Section title.
Sections
~~~~~~~~
AsciiDoc supports five section levels 0 to 4 (although only book
documents are allowed to contain level 0 sections). Section levels are
delineated by the section <<X17,titles>>.
Sections are translated using configuration file markup templates. To
determine which configuration file template to use AsciiDoc first
searches for special section titles in the <<X16,`[specialsections]`>>
configuration entries, if not found it uses the `[sect<level>]`
template.
The `-n` (`--section-numbers`) command-line option auto-numbers HTML
outputs (DocBook line numbering is handled automatically by the
DocBook toolchain commands).
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:
missing section IDs are generated dynamically by the JavaScript TOC
generator *after* the page is loaded. This means, for example, that if
you go to a bookmarked 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 an underscore.
- Strip leading or trailing underscores.
- Convert to lowercase.
- Prepend an underscore (so there's no possibility of name clashes
with existing document IDs).
- 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 Sections
^^^^^^^^^^^^^^^^
In addition to normal sections, documents can contain optional
frontmatter and backmatter sections -- for example: preface,
bibliography, table of contents, index.
The AsciiDoc configuration file `[specialsections]` section specifies
special section titles and the corresponding backend markup templates.
`[specialsections]` entries are formatted like:
<pattern>=<name>
`<pattern>` is a Python regular expression and `<name>` is the name of
a configuration file markup template section. If the `<pattern>`
matches an AsciiDoc document section title then the backend output is
marked up using the `<name>` 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.
AsciiDoc comes preconfigured with the following special section
titles:
Preface (book documents only)
Abstract (article documents only)
Dedication (book documents only)
Glossary
Bibliography|References
Colophon (book documents only)
Index
Appendix [A-Z][:.] <title>
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. Passthroughs
8. 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).
+Monospaced text+::
Word phrases \`enclosed in backtick characters` (grave
accents) or \+plus characters+ are rendered in a monospaced font.
``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).
The alternative underline and plus characters, while marginally less
readable, are arguably a better choice than the backtick and
apostrophe characters as they are not normally used for, and so not
confused with, punctuation.
Quoted text can be prefixed with an <<X21,attribute list>>. Currently
the only use made of this feature is to allow the font color,
background color and size to be specified (XHTML/HTML only, not
DocBook) using the first three positional attribute arguments. 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.
.Quoted text properties
- 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.
- A configuration file `[quotes]` entry can be subsequently undefined
by setting it to a blank value.
[[X52]]
Constrained and Unconstrained Quotes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
There are actually two types of quotes:
Constrained quotes
++++++++++++++++++
Quote text that must be bounded by white space, for example a phrase
or a word. These are the most common type of quote and are the ones
discussed previously.
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...
[TIP]
=====================================================================
The `__`, `**`, `++` and `##` unconstrained quotes have to be
double-escaped (because of their similarity to the single character
constrained quotes) -- here's how to escape the previous example:
\*\*F**ile Open...
=====================================================================
[[X50]]
Inline Passthroughs
~~~~~~~~~~~~~~~~~~~
This special text quoting mechanism passes inline text to the output
document without the usual substitutions. There are two flavors:
\+\++Triple-plus passthrough\+\++::
No change is made to the quoted text, it is passed verbatim to the
output document.
\$$Double-dollar passthrough$$::
Special characters are escaped but no other changes are made.
This passthrough can be prefixed with inline attributes.
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^{amp}#960;i^+1 = 0. H~2~O and x^10^. Some ^super text^
and ~some sub text~
Is rendered like:
e^{amp}#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 (HTML/XHTML)
~~~~~~~~~~~~~~~~~~~~~~~~
A plus character preceded by at least one space character at the end
of a line forces a line break. It generates an HTML line break
(`<br />`) tag. Line breaks are ignored when outputting to DocBook
since it has no line break element.
Rulers (HTML/XHTML)
~~~~~~~~~~~~~~~~~~~
A line of four or more apostrophe characters will generate an HTML
ruler (`<hr />`) tag. Ignored when generating non-HTML output formats.
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 the 'include' block macro
by setting a 'tabsize' attribute in the 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.
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 three 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
(levels 2 and 3 illustrate the optional trailing equals characters
syntax):
= 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.
[[X42]]
BlockTitles
-----------
A BlockTitle element is a single line beginning with a period followed
by a title. The title is applied to the next 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 is
really just an AttributeList with a special syntax which sets the
`\{id}` attribute for substitution in the subsequent block's markup
template.
The 'BlockId' element has the same syntax and serves a similar
function to the <<X30,anchor inline macro>>.
Paragraphs
----------
Paragraphs are terminated by a blank line, the end of file, or the
start of a DelimitedBlock.
Paragraph markup is specified by configuration file `[paradef*]`
sections. AsciiDoc ships with the following predefined paragraph
types:
Default Paragraph
~~~~~~~~~~~~~~~~~
A Default paragraph (`[paradef-default]`) consists of one or more
non-blank lines of text. The first line must start hard against the
left margin (no intervening white space). The processing expectation
of the default paragraph type is that of a normal paragraph of text.
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.
Literal Paragraph
~~~~~~~~~~~~~~~~~
A Literal paragraph (`[paradef-literal]`) consists of one or more
lines of text, where the first line is indented by one or more space
or tab characters. Literal paragraphs are rendered verbatim in a
monospaced font usually without any distinguishing background or
border. There is no text formatting or substitutions within Literal
paragraphs apart from Special Characters and Callouts. 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
Literal paragraph to be misinterpreted as a list -- in situations like
this use a <<X65,LiteralBlock>> in place of a 'LiteralParagraph'.
[[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: ==========================
Filter blocks: ~~~~~~~~~~~~~~~~~~~~~~~~~~
The <<X56,code>>, <<X57,source>> and <<X58,music>> filter blocks are
detailed in the <<X59,Filters>> section.
.Default DelimitedBlock substitutions
`-------------.------------.---------.---------.---------.---------
Passthrough Listing Literal Sidebar Quote
-------------------------------------------------------------------
Callouts No Yes Yes No No
Attributes Yes No No Yes Yes
Inline Macros Yes No No Yes Yes
Quotes No No No Yes Yes
Replacements No No No Yes Yes
Special chars No Yes Yes Yes Yes
Special words No No No Yes Yes
-------------------------------------------------------------------
Listing Blocks
~~~~~~~~~~~~~~
ListingBlocks are rendered verbatim in a monospaced font, they retain
line and whitespace formatting and 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 code and file listings.
Here's an example:
--------------------------------------
#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);
}
--------------------------------------
[[X65]]
Literal Blocks
~~~~~~~~~~~~~~
LiteralBlocks behave just like LiteralParagraphs except you don't have
to indent the contents.
LiteralBlocks can be used to resolve list ambiguity. If the following
list was just indented it would be processed as an ordered list (not
an indented paragraph):
---------------------------------------------------------------------
....................
1. Item 1
2. Item 2
....................
---------------------------------------------------------------------
Renders:
....................
1. Item 1
2. Item 2
....................
SidebarBlocks
~~~~~~~~~~~~~
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.
************************************************
[[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. Here's and example:
---------------------------------------------------------------------
//////////////////////////////////////////
CommentBlock contents are not processed by
asciidoc(1).
//////////////////////////////////////////
---------------------------------------------------------------------
See also <<X25,Comment Lines>>.
Passthrough Blocks
~~~~~~~~~~~~~~~~~~
PassthroughBlocks are for backend specific markup, text is only
subject to attribute and macro substitution. PassthroughBlock content
will generally be backend specific. Here's an example:
---------------------------------------------------------------------
++++++++++++++++++++++++++++++++++++++
<table border="1"><tr>
<td>Cell 1</td>
<td>Cell 2</td>
</tr></table>
++++++++++++++++++++++++++++++++++++++
---------------------------------------------------------------------
Quote Blocks
~~~~~~~~~~~~
QuoteBlocks are used for quoted passages of text. There are two
styles: 'quote' and 'verse' (the first positional attribute). The
'attribution' and 'citetitle' attributes (positional attributes 2 and
3) specify the content author and source. If no attributes are
specified the 'quote' style is used.
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.
=====================================================================
The title prefix that is automatically inserted by asciidoc(1) can be
customized 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>>.
[[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
- Indentation is optional and does not determine nesting, indentation
does however make the source more readable.
- A nested list must use a different syntax from its parent so that
asciidoc(1) can distinguish the start of a nested list.
- By default lists of the same type can only be nested two deep; this
could be increased by defining new list definitions.
- In addition to nested lists a list item will include immediately
following Literal paragraphs.
- Use <<X15, List Item Continuation>> to include other block elements
in a list item.
- 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 and Numbered Lists
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Bulleted list items start with a dash or an asterisk followed by a
space or tab character. Bulleted list syntaxes are:
...................
- List item.
* List item.
...................
Numbered list items start with an optional number or letter followed
by a period followed by a space or tab character. List numbering is
optional. Numbered list syntaxes are:
.....................................................................
. Integer numbered list item.
1. Integer numbered list item with optional numbering.
.. Lowercase letter numbered list item.
a. Lowercase letter numbered list item with optional numbering.
.....................................................................
Here are some examples:
---------------------------------------------------------------------
- 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.
.. Fusce euismod commodo velit.
.. Vivamus fringilla mi eu lacus.
. Donec eget arcu bibendum nunc consequat lobortis.
- 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.
3. Donec eget arcu bibendum nunc consequat lobortis.
4. Nam fermentum mattis ante.
---------------------------------------------------------------------
Which render as:
- 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.
.. Fusce euismod commodo velit.
.. Vivamus fringilla mi eu lacus.
. Donec eget arcu bibendum nunc consequat lobortis.
- 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.
3. Donec eget arcu bibendum nunc consequat lobortis.
4. Nam fermentum mattis ante.
Vertical 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 a double colon `::` or
semi-colon `;;`.
The list item text consists of one or more lines of text starting on
the line immediately following the label and can be followed by nested
List or ListParagraph elements. Item text can be optionally indented.
Here are some examples:
---------------------------------------------------------------------
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.
---------------------------------------------------------------------
Which render as:
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.
Horizontal Labeled Lists
~~~~~~~~~~~~~~~~~~~~~~~~
Horizontal labeled lists differ from vertical labeled lists in that
the label and the list item sit side-by-side as opposed to the item
under the label. Item text must begin on the same line as the label
although you can begin item text on the next line if you follow the
label with a backslash.
The following horizontal list example also illustrates the omission
of optional indentation:
---------------------------------------------------------------------
*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:
*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.
[WARNING]
=====================================================================
- Use vertical labeled lists in preference to horizontal labeled lists
-- current PDF toolchains do not make a good job of determining
the relative column widths.
- If you are generating DocBook markup the 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>> process them correctly).
=====================================================================
Question and Answer Lists
~~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc comes pre-configured with a labeled list for generating
DocBook question and answer (Q&A) lists (`??` label delimiter).
Example:
---------------------------------------------------------------------
Question one??
Answer one.
Question two??
Answer two.
---------------------------------------------------------------------
Renders:
Question one??
Answer one.
Question two??
Answer two.
Glossary Lists
~~~~~~~~~~~~~~
AsciiDoc comes pre-configured with a labeled list (`:-` label
delimiter) for generating DocBook glossary lists. Example:
---------------------------------------------------------------------
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 glossary section.
Bibliography Lists
~~~~~~~~~~~~~~~~~~
AsciiDoc comes with a predefined itemized list (`+` item bullet) for
generating bibliography entries. Example:
---------------------------------------------------------------------
+ [[[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
~~~~~~~~~~~~~~~~~~~~~~
To include subsequent block elements in list items (in addition to
implicitly included nested lists and Literal paragraphs) place a
separator line containing a single plus character between the list
item and the ensuing list continuation element. Multiple block
elements (excluding section Titles and BlockTitles) may be included in
a list item using this technique. For example:
Here's an example of list item continuation:
---------------------------------------------------------------------
1. List item one.
+
List item one continued with a second paragraph followed by an
Indented block.
+
.................
$ ls *.sh
$ mv *.sh ~/tmp
.................
+
List item one continued with a third paragraph.
2. List item two.
List item two literal paragraph (no continuation required).
- Nested list (item one).
Nested list literal paragraph (no continuation required).
+
Nested list appended list item one paragraph
- Nested list item two.
---------------------------------------------------------------------
Renders:
1. List item one.
+
List item one continued with a second paragraph followed by a Listing
block.
+
.................
$ ls *.sh
$ mv *.sh ~/tmp
.................
+
List item one continued with a third paragraph.
2. List item two.
List item two literal paragraph (no continuation required).
- Nested list (item one).
Nested list literal paragraph (no continuation required).
+
Nested list appended list item one paragraph
- Nested list item two.
[[X29]]
List Block
~~~~~~~~~~
A List block is a special delimited block containing a list element.
- All elements between in the List Block are part of the preceding
list item. In this respect the List block behaves like <<X15,List
Item Continuation>> except that list items contained within the
block do not require explicit `+` list item continuation lines:
- The block delimiter is a single line containing two dashes.
- Any block title or attributes are passed to the first element inside
the block.
The List Block is useful for:
1. Lists with long multi-element list items.
2. Nesting a list within a parent list item (by default nested lists
follow the preceding list item).
Here's an example of a nested list block:
---------------------------------------------------------------------
.Nested List Block
1. List item one.
+
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 list item b.
--
+
This paragraph belongs to item 1.
2. Item 2 of the outer list.
---------------------------------------------------------------------
Renders:
.Nested List Block
1. List item one.
+
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 list item b.
--
+
This paragraph belongs to item 1.
2. Item 2 of the outer list.
Footnotes
---------
The shipped AsciiDoc configuration includes the `\footnote:[<text>]`
inline macro for generating footnotes. The footnote text can span
multiple lines. Example footnote:
A footnote footnote:[An example footnote.]
Which renders:
A footnote footnote:[An example footnote.]
Footnotes are primarily useful when generating DocBook output --
DocBook conversion programs render footnote outside the primary text
flow.
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 default syntax is `<name>:<target>[<attributelist>]` (for
inline macros) and `<name>::<target>[<attributelist>]` (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.
- `<attributelist>` is a <<X21,list of attributes>> enclosed in square
brackets.
- The attribute list is mandatory except for URLs and email addresses.
- Expansion of non-system macro references can be escaped by
prefixing a backslash character.
- Block macro attribute reference substitution is performed prior to
macro expansion.
- 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).
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 customized the link caption you can enter the
'http', 'https', 'ftp', 'file' URLs and email addresses without any
special macro syntax.
- If no caption text is specified 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
callto:joe.bloggs[]
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
callto:joe.bloggs[]
- 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 first positional attribute list entry specifies the
alternative text which is displayed if the output application is
unable to process the image file. For example:
image:images/logo.png[Company Logo]
- 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["Company Logo",scaledwidth="75%"]
- The optional `align` attribute is used for horizontal image
alignment in DocBook block images (specifically for PDF documents).
Allowed values are `center`, `left` and `right`. For example:
image::images/tiger.png["Tiger image",align="left"]
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>[<attributelist>]` (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 its
<<X9,inline counterpart>>.
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.
For example:
.Main circuit board
image::images/layout.png[J14P main circuit board]
`xhtml11` and `html4` backends precede the title with a `Figure :`
prefix. You can customize this prefix with the `caption` attribute.
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 referenced by
'image' macros 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 to produce single-file XHTML
documents with embedded images and CSS, for example:
$ asciidoc --unsafe -a data-uri mydocument.txt
You will need to specify the `--unsafe` option because the AsciiDoc
`data-uri` is implemented using the `\{sys}` attribute.
NOTE: Internet Explorer up to version 7 does not support 'data: URIs',
but it is supported by Internet Explorer 8 Beta 1.
*********************************************************************
[[X25]]
Comment Lines
^^^^^^^^^^^^^
Single lines starting with two forward slashes hard up against the
left margin are treated as comments and are stripped from the output.
Comment lines have been implemented as a block macro and are only
valid in a block context -- they are not treated as comments inside
paragraphs or delimited blocks. Example comment line:
// This is a comment.
See also <<X26,Comment Blocks>>.
System Macros
~~~~~~~~~~~~~
System macros are block macros that perform a predefined task which is
hardwired into the asciidoc(1) program.
- You can't 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 main 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.
- File inclusion is limited to a depth of 5 to catch recursive loops.
- 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.
- 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 -- use the `include` macro
instead.
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 forms of conditional inclusion
macro usage, the first includes document text between the `ifdef` and
`endif` macros if a document attribute is defined:
ifdef::<attribute>[]
:
endif::<attribute>[]
The second for 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.
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).
*********************************************************************
eval, sys and sys2 System Macros
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
These 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]
------------------
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.
Macro Definitions
~~~~~~~~~~~~~~~~~
Each entry in the configuration `[macros]` section is a macro
definition which can take one of the following forms:
`<pattern>=<name>`::
Inline macro definition.
`<pattern>=#<name>`::
Block macro definition.
`<pattern>=+<name>`::
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'.
.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
------
Tables are the most complex AsciiDoc elements and this section is
quite long. footnote:[The current table syntax is overly complicated
and unwieldy to edit, hopefully a more usable syntax will appear in
future versions of AsciiDoc.]
NOTE: AsciiDoc generates nice HTML tables, but the current crop of
DocBook toolchains render tables with varying degrees of success. Use
tables only when really necessary.
Example Tables
~~~~~~~~~~~~~~
The following annotated examples are all you'll need to start creating
your own tables.
The only non-obvious thing you'll need to remember are the column stop
characters:
- Backtick (`) -- align left.
- Single quote (') -- align right.
- Period (.) -- align center.
Simple table:
---------------------------------------------------------------------
`---`---
1 2
3 4
5 6
--------
---------------------------------------------------------------------
Output:
`---`---
1 2
3 4
5 6
--------
Table with title, header and footer:
---------------------------------------------------------------------
.An example table
[grid="all"]
'---------.--------------
Column 1 Column 2
-------------------------
1 Item 1
2 Item 2
3 Item 3
-------------------------
6 Three items
-------------------------
---------------------------------------------------------------------
Output:
.An example table
[grid="all"]
`-----------.--------------
Column 1 Column 2
---------------------------
1 Item 1
2 Item 2
3 Item 3
---------------------------
6 Three items
---------------------------
Four columns totaling 15% of the 'pagewidth', CSV data:
---------------------------------------------------------------------
[frame="all"]
````~15
1,2,3,4
a,b,c,d
A,B,C,D
~~~~~~~~
---------------------------------------------------------------------
Output:
[frame="all"]
````~15
1,2,3,4
a,b,c,d
A,B,C,D
~~~~~~~~
A table with a numeric ruler and externally sourced CSV data:
---------------------------------------------------------------------
[frame="all", grid="all"]
.15`20`25`20`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ID,Customer Name,Contact Name,Customer Address,Phone
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include::customers.csv[]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---------------------------------------------------------------------
Renders:
[frame="all", grid="all"]
.15`20`25`20`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ID,Customer Name,Contact Name,Customer Address,Phone
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include::customers.csv[]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AsciiDoc Table Block Elements
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This sub-section details the AsciiDoc table format.
Table ::= (Ruler,Header?,Body,Footer?)
Header ::= (Row+,Underline)
Footer ::= (Row+,Underline)
Body ::= (Row+,Underline)
Row ::= (Data+)
A table is terminated when the table underline is followed by a blank
line or an end of file. Table underlines which separate table headers,
bodies and footers should not be followed by a blank line.
Ruler
^^^^^
The first line of the table is called the 'Ruler'. The Ruler specifies
which configuration file table definition to use, column widths,
column alignments and the overall table width.
There are two ruler formats:
Character ruler::
The column widths are determined by the number of table fill
characters between column stop characters.
Numeric ruler::
The column widths are specified numerically. If a column width
is omitted the previous width is used. In the degenerate case
of no widths being specified columns are allocated equal
widths.
The ruler format can be summarized as:
ruler ::= ((colstop,colwidth?,fillchar*)+, fillchar+, tablewidth?
- The 'ruler' starts with a column stop character (designating the
start of the first column).
- Column stop characters specify the start and alignment of each
column:
* Backtick (`) -- align left.
* Single quote (') -- align right.
* Period (.) -- align center.
- In the case of 'fixed' format tables the ruler column widths specify
source row data column boundaries.
- The optional 'tablewidth' is a number representing the size of the
output table relative to the 'pagewidth'. If 'tablewidth' is less
than one then it is interpreted as a fraction of the page width; if
it is greater than one then it is interpreted as a percentage of
the page width. If 'tablewidth' is not specified then the table
occupies the full 'pagewidth' (numeric rulers) or the relative width
of the ruler compared to the 'textwidth' (character rulers).
Row and Data Elements
^^^^^^^^^^^^^^^^^^^^^
Each table row consists of a line of text containing the same number
of 'Data' items as there are columns in the table,
Lines ending in a backslash character are continued on the next line.
Each 'Data' item is an AsciiDoc substitutable string. The substitutions
performed are specified by the 'subs' table definition entry. Data
cannot contain AsciiDoc block elements.
The format of the row is determined by the table definition 'format'
value:
fixed::
Row data items are assigned by chopping the row up at ruler column
width boundaries.
csv::
Data items are assigned the parsed CSV (Comma Separated Values)
data.
dsv::
The DSV (Delimiter Separated Values) format is a common UNIX tabular
text file format.
- The separator character is a colon (although this can be set to
any letter using the 'separator' table attribute).
- Common C-style backslash escapes are supported.
- Blank lines are skipped.
Underline
^^^^^^^^^
A table 'Underline' consists of a line of three or more 'fillchar'
characters which are end delimiters for table header, footer and body
sections.
Attribute List
^^^^^^^^^^^^^^
The following optional table attributes can be specified in an
<<X21,AttributeList>> preceding the table:
separator::
The default DSV format colon separator can be changed using the
'separator' attribute. For example: `[separator="|"]`.
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 'topbot'.
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 'none'. For
example `[frame="all", grid="none"]`.
format, tablewidth::
See <<X37,Markup Attributes>> below.
You can also use an AttributeList to override the following table
definition and ruler parameters: 'format', 'subs', 'tablewidth'.
[[X37]]
Markup Attributes
^^^^^^^^^^^^^^^^^
The following attributes are automatically available inside table tag
and markup templates.
cols::
The number of columns in the table.
colalign::
Column alignment assumes one of three values ('left', 'right' or
'center'). The value is determined by the corresponding ruler column
stop character (only valid inside 'colspec', 'headdata', 'bodydata'
and 'footdata' tags).
colwidth::
The output column widths are calculated integers (only valid inside
'colspec', 'headdata', 'bodydata' and 'footdata' tags).
colnumber::
The table column number starting at 1 (only valid inside 'colspec',
'headdata`, `bodydata` and `footdata` tags).
format::
The table definition 'format' value (can be overridden with
attribute list entry).
tablewidth::
The ruler 'tablewidth' value (can be overridden with attribute list
entry).
pagewidth::
The 'pagewidth' miscellaneous configuration option.
pageunits::
The 'pageunits' miscellaneous configuration option.
The 'colwidth' value is calculated as (`N` is the ruler column width
number and `M` is the sum of the ruler column widths):
( N / M ) * pagewidth
If the ruler 'tablewidth' was specified the column width is multiplied
again by this value.
There is one exception: character rulers that have no 'pagewidth'
specified. In this case the 'colwidth' value is calculated as (where
`N` is the column character width measured on the table ruler):
( N / textwidth ) * pagewidth
The following attributes are available to the table markup template:
comspecs::
Expands to N substituted 'comspec' tags where N is the number of
columns.
headrows, footrows, bodyrows::
These references expand to sets of substituted header, footer and
body rows as defined by the corresponding row and data configuration
parameters.
rows::
Experimental attribute (number of source lines in table) available
in table markup templates (used by experimental LaTeX backend).
[[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: {revision}
:man manual: AsciiDoc Manual
[[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.
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. A markup template section body can contain:
- Backend markup
- 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.
Special Sections
~~~~~~~~~~~~~~~~
AsciiDoc reserves the following predefined special 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.
tabledef*::
Table element definitions.
Each line of text in a special section 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).
.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
^^^^^^^^^^^^^
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.
textwidth, 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
^^^^^^
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
^^^^
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 double-quote (") characters.
To delete a attribute insert a name only entry in a downstream
configuration file or use the asciidoc(1) `--attribute name!`
command-line option (the attribute name is suffixed with a ! character
to delete it).
Special Characters
^^^^^^^^^^^^^^^^^^
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 `<`.
<=<
Quoted Text
^^^^^^^^^^^
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
^^^^^^^^^^^^^
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
^^^^^^^^^^^^
`[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.
[[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 `/etc/asciidoc` directory (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`
4. `lang-<lang>.conf`
Where `<backend>` and `<doctype>` are values specified by the
asciidoc(1) `-b` (`--backend`) and `-d` (`--doctype`) command-line
options. `<lang>` is the value of the AsciiDoc `lang` attribute
(defaults to `en` (English)).
Finally, 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
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 properties
- 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.
- Special characters in the entry `<value>` are substituted. To
include special characters use the predefined `\{gt}`, `\{lt}`,
`\{amp}` attribute references.
- 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 a
different AttributeEntry substitution set the `attributeentry-subs`
attribute.
- 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's another example:
---------------------------------------------------------------------
AsciiDoc User Manual
====================
:Author: Stuart Rackham
:Email: srackham@gmail.com
:Date: April 23, 2004
:Revision: 5.1.1
:Key words: linux, ralink, debian, wireless
:Revision history:
---------------------------------------------------------------------
Which creates these attributes:
{author}, {firstname}, {lastname}, {authorinitials}, {email},
{date}, {revision}, {keywords}, {revisionhistory}
The preceding example is equivalent to the standard AsciiDoc two line
document header. Actually it's a little bit different with the
addition of the `\{keywords}` and `\{revisionhistory}` attributes
footnote:[The existence of a `\{revisionhistory}` attribute causes a
revision history file (if it exists) to be included in DocBook
outputs. If a file named like `\{docname}-revhistory.xml` exists in
the document's directory then it will be added verbatim to the DocBook
header (see the `./doc/asciidoc-revhistory.xml` example that comes
with the AsciiDoc distribution).].
[[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[]
Using previously defined attributes: See the {1}[Freshmeat summary]
or the {homepage} for something new {new}.
.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 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:
[Hello]
[quote, Bertrand Russell, The World of Mathematics (1956)]
["22 times", backcolor="#0e0e0e", options="noborders,wide"]
.Attribute list properties
- If one or more attribute values contains a comma the all values must
be quoted (enclosed in quotation characters).
- If the list contains any named attributes the all string attribute
values must be quoted.
- List attributes take precedence over existing attributes.
- List attributes can only be referenced in configuration file markup
templates and tags, they are not available inside the document.
- Attribute references are allowed inside attribute lists.
- 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).
- If an attribute named `options` is present it is processed as a
comma separated list of attributes with zero length string values.
For example `[options="opt1,opt2,opt3"]` is equivalent to
`[opt1="",opt2="",opt2=""]`.
- Attribute lists are evaluated as a list of Python function
arguments. If this fails or any of the items do not evaluate to a
string, a number or None then all list items are treated as string
literals.
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.
AttributeList Element
~~~~~~~~~~~~~~~~~~~~~
An attribute list on a line by itself constitutes an 'AttributeList'
block element, its function is to parametrize the following block
element. The list attributes are passed to the next block element for
markup template substitution.
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 behavior
- 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.
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 the attribute name
to calculate a substitution value. Conditional attribute references
take the following forms:
`\{<name>=<value>}`::
`<value>` is substituted if the attribute `<name>` is
undefined otherwise its value is substituted. `<value>` can
contain simple attribute references.
`\{<name>?<value>}`::
`<value>` is substituted if the attribute `<name>` is defined
otherwise an empty string is substituted. `<value>` can
contain simple attribute references.
`\{<name>!<value>}`::
`<value>` is substituted if the attribute `<name>` is
undefined otherwise an empty string is substituted. `<value>`
can contain simple attribute references.
`\{<name>#<value>}`::
`<value>` is substituted if the attribute `<name>` is defined
otherwise the undefined attribute entry causes the containing
line to be dropped. `<value>` can contain simple attribute
references.
`\{<name>%<value>}`::
`<value>` is substituted if the attribute `<name>` is not
defined otherwise the containing line is dropped. `<value>`
can contain simple attribute references.
`\{<name>@<regexp>:<value1>[:<value2>]}`::
`<value1>` is substituted if the value of attribute `<name>`
matches the regular expression `<regexp>` otherwise `<value2>`
is substituted. If attribute `<name>` 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.
`\{<name>$<regexp>:<value1>[:<value2>]}`::
Same behavior as the previous ternary attribute except for
the following cases:
`\{<name>$<regexp>:<value>}`;;
Substitutes `<value>` if `<name>` matches `<regexp>`
otherwise the result is undefined and the containing
line is dropped.
`\{<name>$<regexp>::<value>}`;;
Substitutes `<value>` if `<name>` does not match
`<regexp>` otherwise the result is undefined and the
containing line is dropped.
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>}`.
`\{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. In all
remaining cases the attribute evaluates to a string
representation of the `<expression>` result.
`\{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.
`\{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>`.
.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:
{asciidoc-dir} the asciidoc(1) application directory
{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
{basebackend-<base>} empty string ''
{basebackend} html or docbook
{brvbar} broken vertical bar (|) character
{date} document date (from document header)
{docname} document file name without extension
{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 ''
{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} document input directory name (note 1)
{infile} input file name (note 1)
{lastname} author last name (from document header)
{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)
{outdir} document output directory name (note 1)
{outfile} output file name (note 1)
{revision} document revision number (from document header)
{sectnum} section number (in section titles)
{title} section title (in titled elements)
{user-dir} the ~/.asciidoc directory (if it exists)
{verbose} defined as '' if --verbose command option specified
.NOTES
1. Intrinsic attributes are global so avoid defining custom attributes
with the same names.
2. `\{infile}`, `\{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.]
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.
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 and DelimitedBlocks) 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','passthroughs'.
'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 and DelimitedBlocks). 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",font="monospaced"
- 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 only allowable option is 'listelement'. 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 specific block definition notes:
options::
Allowed values are:
'sectionbody';;
The block contents are processed as a SectionBody.
'skip';;
The block is treated as a comment (see 'CommentBlocks').
'list';;
The block is a <<X29,list block>>.
'presubs', 'postsubs' and 'filter' entries are meaningless when
'sectionbody', 'skip' or 'list' 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 must contain the named
group 'text' which matches text in the first line.
subs::
Substitutions that are performed on list item text and terms.
listtag::
The name of the tag that envelopes the List.
itemtag::
The name of the tag that envelopes the ListItem.
texttag::
The name of the tag that envelopes the list item text.
labeltag::
The name of the tag that envelopes a variable list label.
entrytag::
The name of the tag that envelopes a labeled list entry.
The tag entries map the AsciiDoc list structure to backend markup; see
the AsciiDoc distribution `.conf` configuration files for examples.
Tables
~~~~~~
Table behavior and syntax is determined by `[tabledef*]` configuration
file sections. The user can change existing list behavior and add new
list types by editing configuration files.
Table specific block definition notes:
fillchar::
A single character that fills table ruler and underline
lines.
subs::
Substitutions performed on table data items.
format::
The source row data format ('fixed', 'csv' or 'dsv').
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.
[[X4]]
Table behavior is also influenced by the following `[miscellaneous]`
configuration file entries:
textwidth::
The page width (in characters) of the source text. This setting is
compared to the table ruler width when calculating the relative
size of character ruler tables on the output page.
pagewidth::
This integer value is the printable width of the output media. Used
to calculate 'colwidth' and 'tablewidth' substitution values.
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 definition
('[tabledef-default]') so you only need to override those conf file
entries that require modification when defining a new table type.
[[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.
NOTE: Filter functionality is currently only available on POSIX
platforms (this includes Cygwin).
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`).
Filter Configuration Files
~~~~~~~~~~~~~~~~~~~~~~~~~~
Filters are normally accompanied by a configuration file containing a
Paragraph or DelimitedBlock definition along with corresponding markup
templates.
There are two ways to implement filters:
- As a new Paragraph or DelimitedBlock definition.
- By styling an existing Paragraph or DelimitedBlock using a 'style'
configuration entry -- the 'source highlight' and 'music' filters
use this technique to customize the ListingBlock. By convention the
style is given the same name as the filter.
asciidoc(1) auto-loads all `.conf` files found in the filter search
paths (see previous section).
[[X56]]
Code Filter
~~~~~~~~~~~
AsciiDoc comes with a simple minded for highlighting source code
keywords and comments. See also the
`./filters/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>>.
.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, 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, 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. All you need is
<<X40,xsltproc(1)>>, <<X13,DocBook XSL Stylesheets>> and, optionally
<<X31,dblatex>> or <<X14,FOP>> (if you want PDF), or `lynx(1)` (if you
want 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-options="" 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, revision history, 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.
`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
`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.sh 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 ` `
instead of ` `).
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 <<X61, Example `\~/.vimrc` file>>).
- 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 and numbered
lists. First you need to set the `comments` and `formatoptions` (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
" Q command to reformat paragraphs and list.
nnoremap Q gq}
" W command to delete trailing white space and Dos-returns and to expand tabs
" to spaces.
nnoremap W :%s/[\r \t]\+$//<CR>:set et<CR>:retab!<CR>
autocmd BufRead,BufNewFile *.txt,README,TODO,CHANGELOG,NOTES
\ setlocal autoindent expandtab tabstop=8 softtabstop=2 shiftwidth=2
\ textwidth=70 wrap formatoptions=tcqn
\ 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).
Misinterpreted text formatting::
If text in your document is incorrectly interpreted as formatting
instructions you can suppress formatting by placing a backslash
character immediately in front of the leading quote character(s).
For example in the following line the backslash prevents text
between the two asterisks from being output in a strong (bold)
font:
Add `\*.cs` files and `*.resx` files.
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.
Escaping inside DSV table data::
Delimiter separated text uses C style backslash escape sequences.
If you want to enter a backslash (for example, to escape AsciiDoc
text formatting or an inline macro) you need to escape it by
entering two backslashes.
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 'companyname=Bill & Ben' 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]
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 instead of starting at level 1
the section levels of the combined document start at level 0 (the
document title level).
The solution is to redefine the title underlines so that document and
section titles are pushed down one level.
. Push the standard title underlines down one level by defining a new
level 0 underline in a custom configuration file. For example
`combined.conf`:
[titles]
underlines="__","==","--","~~","^^"
. If you use single line titles you'll need to make corresponding
adjustments to the `[titles]` section `sect0`...`sect4` entries.
. Create a top level wrapper document. For example `combined.txt`:
+
---------------------------------------------------------------------
Combined Document Title
_______________________
include::document1.txt[]
include::document2.txt[]
include::document3.txt[]
---------------------------------------------------------------------
. Process the wrapper document. For example:
$ asciidoc --conf-file=combined.conf combined.txt
Actually the `--conf-file` option is unnecessary as asciidoc(1)
automatically looks for a same-named `.conf` file.
- The combined document title uses the newly defined level 0 underline
(underscore characters).
- 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.
If you want to promote the section levels up one level, so the
document is processed just like a stand-alone document, then pop the
section underline definition up one level:
[titles]
underlines="--","~~","^^","++","__"
The last `"__"` underline is a dummy that won't actually be used but
is necessary to legitimize the underline definition.
This is just the reverse of the technique used for combining separate
documents explained in the previous section.
Processing Document Chunks
~~~~~~~~~~~~~~~~~~~~~~~~~~
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="para"><p>Hello <strong>World!</strong></p></div>
The `-s` (`--no-header-footer`) command-line option suppresses header
and footer output and is useful if the processed output is to be
included in another file.
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. Or use Dave Raggett's excellent 'HTML Tidy' program to tidy
asciidoc(1) output. Example:
$ asciidoc -b docbook -o - mydoc.txt | tidy -indent -xml >mydoc.xml
'HTML Tidy' can be downloaded from http://tidy.sourceforge.net/
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.
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.
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 A: 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).
[[X32]]
Version 6 to version 7
~~~~~~~~~~~~~~~~~~~~~~
The changes that affect the most users relate to renamed and
deprecated backends and command-line syntax:
. The 'html' backend has been renamed 'html4'.
. The 'xhtml' backend has been deprecated to 'xhtml-deprecated' (use
the new 'xhtml11' backend in preference).
. The use of CSS specific `css` and `css-embedded` backends has been
dropped in favor of using attributes (see the table below and
<<X33,xhtml backend attributes>>).
. Deprecated features that emitted warnings in prior versions are no
longer tolerated.
. The command-line syntax for deleting (undefining) an attribute has
changed from `-a ^name` to `-a name!`.
.Equivalent command-line syntax
[grid="all"]
```~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Version 6 (old),Version 7 (new),Version 7 (backward compatible)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-b html,-b html4,-b html4
-b css,-b xhtml11 -a linkcss -a icons,-b xhtml-deprecated -a css -a linkcss -a icons
-b css-embedded,-b xhtml11 -a icons,-b xhtml-deprecated -a css -a icons
-b xhtml,-b xhtml11,-b xhtml-deprecated
-b docbook-sgml,-b docbook -a sgml,-b docbook -a sgml
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you've customized version 6 distribution stylesheets then you'll
need to either bring them in line with the new
`./stylesheets/xhtml11*.css` class and id names or stick with the
backward compatible `xhtml-deprecated` backend.
Changes to configuration file syntax:
. To undefine an attribute in the `[attributes]` section use `name!`
instead of `name` (`name` now sets that attribute to a blank
string).
[[X38]]
Appendix B: Packager Notes
---------------------------
Read the `README` and `INSTALL` files (in the distribution root
directory) for install prerequisites and procedures.
The distribution `install.sh` shell script is the canonical
installation procedure and is the definitive installation description.
Here's a summary of the installation procedure:
- Unpack entire distribution tarball to `/usr/share/asciidoc/`.
- Move `asciidoc.py` to `/usr/bin/`; rename to `asciidoc`; if
necessary modify shebang line; ensure executable permissions are
set.
- Move `a2x` to `/usr/bin/`; if necessary modify shebang line; ensure
executable permissions are set.
- Move the `./*.conf` files to `/etc/asciidoc/`.
- Move `./filters/{\*.conf,*.py}` to `/etc/asciidoc/filters/`.
- Move `./docbook-xsl/*.xsl` to `/etc/asciidoc/docbook-xsl/`.
- Move `./dblatex/*.{xsl,sty}` to `/etc/asciidoc/dblatex/`.
- Copy `./stylesheets/*.css` to `/etc/asciidoc/stylesheets/`.
- Copy `./javascripts/*.js` to `/etc/asciidoc/javascripts/`.
- Copy `./images/icons/*` to `/etc/asciidoc/images/icons/`
(recursively including the `icons` subdirectory and its contents).
- Compress the asciidoc(1) and ax2(1) man pages (`./doc/*.1`) with
gzip(1) and move them to `/usr/share/man/man1/`.
- If Vim is installed then install Vim syntax and filetype detection
files.
Leaving stylesheets and images in `/usr/share/asciidoc/` ensures the
docs and example website are not broken.
[[X39]]
Appendix C: AsciiDoc Safe Mode
------------------------------
AsciiDoc 'safe mode' skips potentially dangerous sections in AsciiDoc
source files by inhibiting the execution of arbitrary code or the
inclusion of arbitrary files.
The safe mode is enabled by default and can only be disabled using the
asciidoc(1) `--unsafe` 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 D: 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, revision history, 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 or xhtml 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 example `lang-es.conf` file
that comes with the AsciiDoc distribution).
- 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 E: ASCIIMathML Support
-------------------------------
http://www1.chapman.edu/~jipsen/mathml/asciimath.html[ASCIIMathML] is
a clever JavaScript written by Peter Jipsen that transforms
mathematical formulae written in plain text to standard mathematical
notation on an HTML page.
To enable ASCIIMathML support on the `xhtml11` backend include the `-a
asciimath` command-line option. Here's what the `asciimath` attribute
does:
- Embeds the `ASCIIMathML.js` script in the output document (links it
if `-a linkcss` has been specified).
- Escapes ASCIIMathML delimiters.
When entering ASCIIMathML formulas you *must* enclose them inside
<<X50,double-dollar passthroughs>> (this is necessary because
ASCIIMathML characters clash with AsciiDoc formatting characters). The
double-dollar passthrough has the bonus of also escaping special
characters so the output document is valid XHTML. You can see an
ASCIIMathML example at
http://www.methods.co.nz/asciidoc/asciimath.html, the same example
can be found in the AsciiDoc distribution `./doc` directory.
[NOTE]
=====================================================================
- See the
http://www1.chapman.edu/~jipsen/mathml/asciimath.html[ASCIIMathML]
website for ASCIIMathML documentation and the latest version.
- If you use Mozilla you need to install the
http://www.mozilla.org/projects/mathml/fonts/[required math fonts].
- If you use Microsoft Internet Explorer 6 you need to install
http://www.dessci.com/en/products/mathplayer/[MathPlayer].
=====================================================================
Appendix F: Vim Syntax Highlighter
----------------------------------
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. This list of limitations also discusses how to work
around the problems:
- Indented lists with preceding blank lines are sometimes mistaken
for literal (indented) paragraphs. You can work around this by
deleting the preceding blank line, or inserting a space in the
preceding blank lines, or putting a list continuation character
(`+`) in the preceding blank line.
- Nested text formatting is highlighted according to the outer format.
- Most escaped inline elements will be highlighted.
- Unterminated quotes are highlighted, for example `'tis` would be
seen as the start of emphasized text. As a damage control measure
quoted text and macro attribute list containing quoted text always
terminate at a blank line. This problem is usually ameliorated by
the fact that characters such as `\~`, `+`, `^` and `_` will
normally occur inside monospaced quotes (unless they are used for
quoting), for example `~/projects`.
- If a closing block delimiter is not preceded by a blank line it is
sometimes mistaken for a title underline. A workaround is to insert
a blank line before the closing delimiter.
- If a list block delimiter is mistaken for a title underline precede
it with a blank line.
- Tables are terminated by a blank line -- use a space character on
blank lines within your table.
- Lines within a paragraph beginning with a period will be highlighted
as block titles. For example:
.chm file.
+
To work around this restriction move the last word of the previous
line to the start of the current (although words starting with a
period should probably be quoted monospace which would also get around
the problem).
TIP: Sometimes incorrect highlighting is caused by preceding lines
that appear blank but contain white space characters -- setting your
editor options so that white space characters are visible is a good
idea.
