AsciiDoc User Guide

AsciiDoc
Text based document generation

  - »Home »Man Page »User Guide »a2x »README »ChangeLog »Installation »Downloads »Support »Page Source | # AsciiDoc User Guide Stuart Rackham `<srackham@methods.co.nz>` version 8.2.1, 06 April 2007 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. ## 1. 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 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, man page, HTML and other presentation 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 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. DocBook has emerged as the defacto 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. ## 2. Getting Started ### 2.1. Installing AsciiDoc See the `README` and `INSTALL` files for install prerequisites and procedures. Packagers take a look at Appendix B: Packager Notes. ### 2.2. 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. ## 3. 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. ### 3.1. article Used for short documents, articles and general documentation. See the AsciiDoc distribution `./doc/article.txt` example. ### 3.2. 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 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. ### 3.3. manpage Used to generate UNIX manual pages. AsciiDoc manpage documents observe special header title and section naming conventions — see the Manpage Documents section for details. See also the `asciidoc(1)` man page source (`./doc/asciidoc.1.txt`) from the AsciiDoc distribution. ## 4. 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: ### 4.1. 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 converting DocBook files to presentation formats such as Postscript, HTML, PDF, DVI, 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 `encoding` attribute to set the character set encoding. 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). ### 4.2. 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 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
  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). 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. iconsdir The name of the directory containing linked admonition and navigation icons. Defaults to `./images/icons`.
  | The `iconsdir` path is relative to the generated HTML output i.e. it is the icon directory path at document view time rather than at document creation time.
  - theme Use alternative stylesheets (see Stylesheets). badges Link badges (XHTML 1.1, CSS and Get Firefox!) in document footers. By default badges are omitted (badges is undefined). 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). #### 4.2.1. Stylesheets AsciiDoc XHTML output is styled using CSS2 stylesheets from the distribution `./stylesheets/` directory.
| Browser CSS support varies from browser to browser. The shipped examples work well on IE6, IE7, Firefox 1.0 and up, Mozilla 1.7 and up, Opera 8 and Konqueror 3.4 but have not been tested on other browsers. All browsers have CSS quirks, but Microsoft's IE6 has so many omissions and errors that in order to separate clean CSS from the IE6 workarounds a separate `xhtml11-quirks.css` stylesheet is used. If you're not viewing your documents with IE6 then the quirks stylesheet 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`. ### 4.3. html4 This backend generates plain (unstyled) HTML 4.01 Transitional markup. ### 4.4. linuxdoc
| 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`. ### 4.5. 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. ## 5. Document Structure An AsciiDoc document consists of a series of 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. ### 5.1. 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 [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 list continuation element. ### 5.2. Header The Header is optional but must start on the first line of the document and must begin with a document 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. The email address is 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: A 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@methods.co.nz>
    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 Attribute Entry elements. ### 5.3. Preamble The Preamble is an optional untitled section body between the document Header and the first Section title. ### 5.4. 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 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 `[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). #### 5.4.1. 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 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>
### 5.5. Inline Elements 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. ## 6. Document Processing The AsciiDoc source document is read and processed as follows: 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. Each document Section is processed and its constituent elements translated to the output file. 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: Special characters Quotes Special words Replacements Attributes Inline Macros Passthroughs Replacements2 The substitutions and substitution order performed on Title, Paragraph and DelimitedBlock elements is determined by configuration file parameters. ## 7. Text Formatting ### 7.1. 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 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 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. #### 7.1.1. 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...
### 7.2. 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. ### 7.3. 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: eπi+1 = 0. H2O and x10. Some super text and some sub text Superscripts and subscripts are implemented as unconstrained quotes so they can be escaped with a leading backslash and prefixed with with an attribute list. ### 7.4. 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. ### 7.5. 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. ### 7.6. 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` ### 7.7. Replacements The following replacements are defined in the default AsciiDoc configuration:
    (C) copyright, (TM) trademark, (R) registered trademark,
    -- em dash, ... ellipsis.
Which are rendered as: © copyright, ™ trademark, ® registered trademark, — em dash, … ellipsis. The Configuration Files section explains how to configure your own replacements. ### 7.8. Special Words Words defined in `[specialwords]` configuration file sections are automatically marked up without having to be explicitly notated. The Configuration Files section explains how to add and replace special words. ## 8. Titles Document and section titles can be in either of two formats: ### 8.1. 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
    ~~~~~~~~~~~~~~~~~~~~~~~~
### 8.2. 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. ## 9. 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. ## 10. 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 anchor inline macro. ## 11. 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: ### 11.1. 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 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: Consul necessitatibus per id, consetetur, eu pro everti postulant homero verear ea mea, qui. ### 11.2. 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.
### 11.3. 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:
| This is an example note.
| If your admonition is more than a single paragraph use an admonition block instead.
#### 11.3.1. Admonition Icons and Captions
| 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 `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 `icons` attribute, for example using the `-a icons` command-line option. The `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 admonition icons have been enabled):
    [icons=None, caption="My Special Note"]
    NOTE: This is my special note.
This subsection also applies to Admonition Blocks. ## 12. 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. ### 12.1. 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:    code~~~~~~~~~~~~~~~~~~~~~~
                      source~~~~~~~~~~~~~~~~~~~~
                      music~~~~~~~~~~~~~~~~~~~~~
The code, source and music filter blocks are detailed in the Filters section.
Table: 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
### 12.2. 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);
    }
### 12.3. 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
The literal block has a verse style (useful for lyrics and poems). For example:
    [verse]
    ......................................
    Consul *necessitatibus* per id,
    consetetur, eu pro everti postulant
    homero verear ea mea, qui.

    Qui in magna commodo, est labitur
    dolorum an. Est ne *magna primis
    adolescens*.
    ......................................
Renders: Consul necessitatibus per id, consetetur, eu pro everti postulant homero verear ea mea, qui. Qui in magna commodo, est labitur dolorum an. Est ne magna primis adolescens. ### 12.4. 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: Any AsciiDoc SectionBody element (apart from SidebarBlocks) can be placed inside a sidebar. ### 12.5. 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 Comment Lines. ### 12.6. 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>
    ++++++++++++++++++++++++++++++++++++++
### 12.7. Quote Blocks QuoteBlocks are used for quoted passages of text. attribution and citetitle named attributes specify the author and source of the quote (they are equivalent to positional attribute list entries 1 and 2 respectively). Both attributes are optional and the block body is treated like a SectionBody. For example:
    [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: A good notation has subtlety and suggestiveness which at times makes it almost seem like a live teacher. The World of Mathematics (1956) — Bertrand Russell In this example unquoted positional attributes have been used, the following quoted positional and named attributes are equivalent (if the attribute list contained commas then quoting would have been mandatory):
    ["Bertrand Russell","The World of Mathematics (1956)"]
    [attribution="Bertrand Russell",citetitle="The World of Mathematics (1956)"]
You can render poems and lyrics with a combination of Quote and Literal blocks. For example:
    [William Blake,from Auguries of Innocence]
    _____________________________________________________________________
    [verse]
    .....................................................................
    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: 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. from Auguries of Innocence — William Blake ### 12.8. 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: Example: 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.
    =====================================================================
### 12.9. Admonition Blocks The ExampleBlock definition includes a set of admonition styles (NOTE, TIP, IMPORTANT, WARNING, CAUTION) for generating admonition blocks (admonitions containing more than just a 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:
| 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 Admonition Icons and Captions. ## 13. 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 List Item Continuation to include other block elements in a list item. The `listindex` 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. ### 13.1. 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. Fusce euismod commodo velit. Fusce euismod commodo velit. Vivamus fringilla mi eu lacus. Donec eget arcu bibendum nunc consequat lobortis. Vivamus fringilla mi eu lacus. Donec eget arcu bibendum nunc consequat lobortis. Nam fermentum mattis ante. ### 13.2. 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. ### 13.3. 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.
| 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 DocBook XSL Stylesheets process them correctly).
### 13.4. 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. ### 13.5. 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.
| To generate valid DocBook output glossary lists must be located in a glossary section.
### 13.6. 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.
| To generate valid DocBook output bibliography lists must be located in a bibliography section.
### 13.7. 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.
1. Renders: List item one. List item one continued with a second paragraph followed by a Listing block.
       $ ls *.sh
       $ mv *.sh ~/tmp
2. List item one continued with a third paragraph. 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. ### 13.8. 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 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: Lists with long multi-element list items. 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 List item one. This paragraph is part of the preceding list item This list is nested and does not require explicit item continuation. This paragraph is part of the preceding list item List item b. This paragraph belongs to list item b. This paragraph belongs to item 1. Item 2 of the outer list. ## 14. 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 [An example footnote.] Footnotes are primarily useful when generating DocBook output — DocBook conversion programs render footnote outside the primary text flow. ## 15. 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.
| 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.
## 16. 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)
This directory holds MS-DOS. System startup code for DOS. 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. ### 16.1. 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. ## 17. 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@methods.co.nz[]
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 list of attributes enclosed in square brackets. The attribute list is mandatory even if it contains no attributes. 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. ### 17.1. Inline Macros Inline Macros occur in an inline element context. Predefined Inline macros include URLs, image and link macros. #### 17.1.1. URLs Standard http, https, ftp, file, mailto and callto URLs are rendered using predefined inline macros. The default AsciiDoc inline macro syntax is very similar to a URL: all you need to do is append an attribute list containing an optional caption immediately following the URL. If no caption text is provided the URL itself is displayed. Here are some examples:
    http://www.methods.co.nz/asciidoc/[The AsciiDoc home page]
    mailto:joe.bloggs@foobar.com[email Joe Bloggs]
    mailto:joe.bloggs@foobar.com[]
    callto:joe.bloggs[]
Which are rendered: The AsciiDoc home page email Joe Bloggs joe.bloggs@foobar.com joe.bloggs
| If the `<target>` necessitates space characters they should be replaced by `%20`. For example `large%20image.png`.
#### 17.1.2. 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. ##### 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 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. If `<caption>` is not specified then the `<id>`, enclosed in square brackets, is displayed. Example:
    <<X21,attribute lists>>
#### 17.1.3. Linking to Local Documents Hypertext links to files on the local filesystem 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 `image` macro. #### 17.1.4. 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. 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` named attributes scale the image size and can be used in any combination. The following example scales the previous example to a height of 32 pixels:
      image:images/logo.png["Company Logo",height=32]
- The optional `link` named 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"]
### 17.2. 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`. #### 17.2.1. Block Identifier The Block Identifier macro sets the `id` attribute and has the same syntax as the 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. #### 17.2.2. 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 macro attributes as its 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]
#### 17.2.3. 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 Comment Blocks. ### 17.3. 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. #### 17.3.1. 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 an attribute is undefined then the included file is silently skipped. The tabsize macro attribute sets the the number of space characters to be used for tab expansion in the included file. #### 17.3.2. Conditional Inclusion Macros Lines of text in the source document can be selectively included or excluded from processing based on the 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. 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). #### 17.3.3. eval, sys and sys2 System Macros These block macros exhibit the same behavior as their same named 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]
    ------------------
#### 17.3.4. 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 section content but can be included in any section. `template::[]` macros cannot be nested. `template::[]` macro expansion is applied to all sections after all configuration files have been read. ### 17.4. 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 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. ## 18. Tables Tables are the most complex AsciiDoc elements and this section is quite long. [The current table syntax is overly complicated and unwieldy to edit, hopefully a more usable syntax will appear in future versions of AsciiDoc.]
| 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.
### 18.1. 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:
Table: An example table
Column 1 | Column 2
--- | ---
6 | Three items
1 | Item 1
2 | Item 2
3 | Item 3
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:
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:
ID | Customer Name | Contact Name | Customer Address | Phone
--- | --- | --- | --- | ---
AROUT | Around the Horn | Thomas Hardy | 120 Hanover Sq. London | (171) 555-7788
BERGS | Berglunds snabbkop | Christina Berglund | Berguvsvagen 8 Lulea | 0921-12 34 65
BLAUS | Blauer See Delikatessen | Hanna Moos | Forsterstr. 57 Mannheim | 0621-08460
BLONP | Blondel pere et fils | Frederique Citeaux | 24, place Kleber Strasbourg | 88.60.15.31
BOLID | Bolido Comidas preparadas | Martin Sommer | C/ Araquil, 67 Madrid | (91) 555 22 82
BONAP | Bon app' | Laurence Lebihan | 12, rue des Bouchers Marseille | 91.24.45.40
BOTTM | Bottom-Dollar Markets | Elizabeth Lincoln | 23 Tsawassen Blvd. Tsawassen | (604) 555-4729
BSBEV | B's Beverages | Victoria Ashworth | Fauntleroy Circus London | (171) 555-1212
CACTU | Cactus Comidas para llevar | Patricio Simpson | Cerrito 333 Buenos Aires | (1) 135-5555
### 18.2. 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. #### 18.2.1. 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). #### 18.2.2. 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. #### 18.2.3. 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. #### 18.2.4. Attribute List The following optional table attributes can be specified in an 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 Markup Attributes below. You can also use an AttributeList to override the following table definition and ruler parameters: format, subs, tablewidth. #### 18.2.5. 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). ## 19. 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. Use the `man(1)` command to view the manpage file (you must include a file path even if it's only `./` otherwise `man(1)` will look for the file in the system manpage locations):
    $ man ./asciidoc.1
To print a high quality man page to a postscript printer:
    $ groff -mandoc -Tps asciidoc.1 | lpr
To find out more about man pages view the `man(7)` manpage (`man 7 man` command). ### 19.1. 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. ### 19.2. 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
### 19.3. The SYNOPSIS Section The second manpage section is mandatory and must be titled SYNOPSIS. ## 20. 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. ### 20.1. 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.
| When creating custom configuration files you only need to include the sections and entries that differ from the default configuration.
| 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.
  ### 20.2. 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. ### 20.3. 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. If you want the `name` to end in a backslash then you need to place two backslashes at the end of the name. `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). #### 20.3.1. 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 Table Configuration File Definitions sub-section.
| `[miscellaneous]` configuration file entries can be set using the `asciidoc(1)` `-a` (`—attribute`) command-line option.
  #### 20.3.2. 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 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. #### 20.3.3. 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. #### 20.3.4. 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). #### 20.3.5. 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 `&lt;`.
    <=&lt;
#### 20.3.6. 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
If you set the tag to `none` then a blank string will be substituted for the quoted text which has the effect of dropping the quoted text from the output document. 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. #### 20.3.7. 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 [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. #### 20.3.8. 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. ### 20.4. 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: The `/etc/asciidoc` directory (if it exists). The directory containing the asciidoc executable. The user's `$HOME/.asciidoc` directory (if it exists). The directory containing the AsciiDoc source file. The following implicit configuration files from each of the above locations are loaded in the following order: `asciidoc.conf` `<backend>.conf` `<backend>-<doctype>.conf` Where `<backend>` and `<doctype>` are values specified by the `asciidoc(1)` `-b` (`—backend`) and `-d` (`—doctype`) command-line options. 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
1. Configuration files (if they exist) will be processed in the following order: 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
| Use the `asciidoc(1)` `-v` (`—verbose`) command-line option to see which configuration files are loaded and the order in which they are loaded.
## 21. 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.
| 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.
## 22. 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 included special characters use `{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.
| The `author` attribute as a special case, it also sets the `firstname`, `surname`, `middlename` and `authorinitials` attributes.
Here's another example:
    AsciiDoc User Manual
    ====================
    :Author:    Stuart Rackham
    :Email:     srackham@methods.co.nz
    :Date:      April 23, 2004
    :Revision:  5.1.1
    :Key words: linux, ralink, debian, wireless
    :Revision history:
Which creates these attributes:
    {author}, {firstname}, {surname}, {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 [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).] . ## 23. 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]
    [Bertrand Russell, The World of Mathematics (1956)]
    ["22 times", backcolor="#0e0e0e", options="noborders,wide"]
  Attribute list properties 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. If the list contains any named attributes the all string attribute values must be quoted. Quoted named attribute values have the same syntax and semantics as Python string literals. 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=""]`. ### 23.1. 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. ### 23.2. 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. ## 24. 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. ### 24.1. 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. ### 24.2. 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>` 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. #### 24.2.1. 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}
### 24.3. 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. `{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. ## 25. Intrinsic Attributes Intrinsic attributes are simple attributes that are created automatically from document header parameters, `asciidoc(1)` command-line arguments, environment parameters along with attributes defined in the default configuration files. Here's the list of predefined intrinsic attributes:
    {amp}                 ampersand (&) character
    {asciidoc-dir}        the asciidoc(1) application directory
    {asciidoc-version}    the version of asciidoc(1)
    {author}              author's full name ({firstname} {middlename} {lastname})
    {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
    {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 `{infile}`, `{outdir}`, `{infile}`, `{indir}` attributes are effectively read-only (you can set them but it won't affect the input or output file paths). See also the xhtml11 subsection for attributes that relate to AsciiDoc XHTML file generation. 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. [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.] ## 26. Block Element Definitions The syntax and behavior of Paragraph, DelimitedBlock, List and Table block elements is determined by block definitions contained in 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 `[misc]` 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 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 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. ### 26.1. 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 named attributes. ### 26.2. 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: It must exist and be defined in a configuration file section named `[paradef-default]`. 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: The paragraph text is aligned to the left margin. Optional presubs inline substitutions are performed on the paragraph text. 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. Optional postsubs inline substitutions are performed on the paragraph text. The paragraph text is enveloped by the paragraph's markup template and written to the output file. ### 26.3. 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 list block. presubs, postsubs and filter entries are meaningless when sectionbody, skip or list options are set. DelimitedBlock processing proceeds as follows: Optional presubs substitutions are performed on the block contents. 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. Optional postsubs substitutions are performed on the block contents. The block contents is enveloped by the block's markup template and written to the output file.
| Attribute expansion is performed on the block filter command before it is executed, this is useful for passing arguments to the filter.
### 26.4. 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. ### 26.5. 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. 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 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. ## 27. 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.
| Filters can potentially generate unsafe output. Before installing a filter you should verify that it can't be coerced into generating malicious output or exposing sensitive information.
| Filter functionality is currently only available on POSIX platforms (this includes Cygwin).
### 27.1. 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`). ### 27.2. Filter Configuration Files Filters are normally accompanied by a configuration file containing a filter Paragraph or filter DelimitedBlock definition and corresponding markup templates. By convention delimiters belonging to DelimitedBlock filters distributed with AsciiDoc consist of a word (normally a noun identifying the block content) followed by four or more tilde characters. `asciidoc(1)` auto-loads all `.conf` files found in the filter search paths (see previous section). ### 27.3. Code Filter AsciiDoc comes with a simple minded for highlighting source code keywords and comments. See also the `./filters/code-filter-readme.txt` file.
| 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 Source Code Highlighter Filter.
    .Code filter example
    [python]
    code~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ''' 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
    code~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Outputs: Example: Code filter example
    ''' 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
### 27.4. Source Code Highlighter Filter A source code highlighter filter can be found in the AsciiDoc distribution `./filters` directory. It uses GNU source-highlight to generate nicely formatted source code for most common programming languages. ### 27.5. Music Filter A music filter is included in the distribution `./filters` directory. It translates music in LilyPond or ABC notation to standard Western classical notation in the form of a trimmed PNG image which is automatically inserted into the output document. ## 28. 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). A wide range of user output format requirements coupled with a choice of available tools and stylesheets results in many valid tool chain combinations. The DocBook toolchain currently used for processing AsciiDoc documentation is xsltproc(1), FOP and DocBook XSL Stylesheets. These tools are freely available for Linux and Windows systems. 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. On the other hand, HTML output directly from AsciiDoc is much faster, can be used in situations where there is no suitable DocBook toolchain and can produce highly customized output (see the AsciiDoc website for example). If you require output formats other than HTML you would feed AsciiDoc's DocBook output to a DocBook toolchain. The distributed PDF documents have been generated in this way. The toolchain processing steps are: Convert AsciiDoc (`*.txt`) documents to DocBook XML (`*.xml`) using AsciiDoc. Convert DocBook XML documents to HTML, XSL-FO or HTML Help files using DocBook XSL Stylesheets and the `xsltproc(1)` XML parser. Convert the XSL-FO (`*.fo`) files to PDF using FOP and HTML Help source (`*.hhp`) files to HTML Help (`*.chm`) files using the Microsoft HTML Help Compiler.
| These steps can be automated by using the AsciiDoc `a2x(1)` toolchain wrapper command.
Depending on your Linux distribution toolchain installation can be a mission for users used to a GUI environment, even more so under Microsoft Windows. So you may like to try the XMLmind FO Converter, it contains a GUI XSL Utility which makes a creditable job of converting AsciiDoc generated DocBook files to RTF, HTML and Open Document formats. The FO Converter Personal Edition can be used free of charge and a Windows installer is available and there is also a UNIX version. Thanks to Matthew Marshall for this tip. ### 28.1. a2x Toolchain Wrapper One of the biggest hurdles for new users seems to be using a DocBook XML toolchain. `a2x(1)` can help — it's a toolchain wrapper command that will generate XHTML (chunked and unchunked), PDF, 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 xsltproc(1), DocBook XSL Stylesheets and optionally FOP (if you want PDF) or lynx(1) (if you want text). The following example generates `doc/quickstart.pdf` from the AsciiDoc `doc/quickstart.txt` source file:
    $ a2x -f pdf --icons doc/quickstart.txt
See the `a2x(1)` man page for details.
| Use the `—verbose` command-line option to view executed toolchain commands.
  ### 28.2. Toolchain Components AsciiDoc Converts AsciiDoc (`*.txt`) files to DocBook XML (`*.xml`) files. 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 `xsltproc(1)`. xsltproc `xsltproc` is a command line XML parser for applying XSLT stylesheets (in our case the DocBook XSL Stylesheets) to XML documents. FOP The Apache Formatting Objects Processor converts XSL-FO (`*.fo`) files to PDF files (see the FOP section). 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. ### 28.3. AsciiDoc DocBook XSL Drivers You will have noticed that the distributed PDF, 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 Stylesheet drivers 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`. ### 28.4. FOP XSL Stylesheets can be used to generate FO (Formatting Object) files, which in turn can be used to produce PDF files using the Apache Formatting Object Processor program (FOP). The FOP home page is at http://xml.apache.org/fop/. As of version 0.20.5 installation and configuration of FOP is a manual process. You also need a working Java Runtime to run FOP. You'll find FOP and Java installation information in the appendices.
| Once you've got FOP installed use the AsciiDoc `a2x(1)` toolchain wrapper to generate PDF files from AsciiDoc source.
## 29. 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 `a2x(1)` toolchain wrapper utility. ## 30. 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).
| If you get an undefined entity error when processing DocBook files you'll may find that you've used an undefined HTML character entity. An easy (although inelegant) fix is to use the character's character code instead of its symbolic name (for example use `&#160;` instead of `&nbsp;`).
If your system has been configured with an XML catalog you may find a number of entity sets are already automatically included. ### 30.1. 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. ## 31. 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. Examples:
    $ asciidoc --help=manpage
    $ asciidoc --help=syntax
### 31.1. Customizing Help To change, delete or add your own help topics edit a `help.conf` file. The file location will depend on whether you want the topics to apply to all users, to a single user or to a single project. Help topics are stored `help.conf` text files. The help topic files have the same named section format as other configuration files. The `help.conf` files are stored in the same locations and loaded in the same order as other configuration files. When the a `--help` command-line option is specified AsciiDoc loads the `help.conf` 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. If a matching help file section is not found a list of available topics is printed. ## 32. Tips and Tricks ### 32.1. 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. Tips for vim users follow. ### 32.2. Vim Commands for Formatting AsciiDoc The Vim text editor's `gq` command is great for reformatting and indenting AsciiDoc paragraphs and lists.
| The Vim website (http://www.vim.org) has a wealth of resources, including scripts for automated spell checking and ASCII Art drawing.
#### 32.2.1. 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: Position the cursor at the start of the paragraph. Type `gq}`. Execute `:help gq` command to read about the vim gq command.
| Put `set` commands in your `~/.vimrc` file so you don't have to enter them manually.
#### 32.2.2. Format Lists The `:gq` command can also be used to format bulleted and numbered lists. First you need to: Set the `textwidth` right wrap margin. Set the `formatoptions` n flag to enable numbered list reformatting (this flag also requires the `autoindent` option be set). Add `fb:*,fb:.,fb:+,fb:>` to the `comments` option to assist the Vim `:gq` command reformat the AsciiDoc bulleted and numbered lists (in the example the C style comments middle part (`mb:*`) has been dropped to avoid ambiguity). Run the vim `:help format-comments` command for more about reformatting). For example:
    :set textwidth=70 formatoptions=tcqn autoindent
    :set comments=s1:/*,ex:*/,://,b:#,:%,fb:-,fb:*,fb:.,fb:+,fb:>
Now you can format simple lists that use dash, asterisk, period and plus bullets along with numbered ordered lists: Position the cursor at the start of the list. Type `gq}`.
| 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.
Here's how I setup my `.vimrc` file:
    nnoremap Q gq}

    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:>
  #### 32.2.3. Indent Paragraphs Indent whole paragraphs by indenting the fist line with the desired indent and then executing the `gq}` command. ### 32.3. 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 AsciiDoc Backends section if AsciiDoc output is rejected as non-conformant by a backend processor. ### 32.4. 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 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 &amp; 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]
1. ### 32.5. 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="__","==","--","~~","^^"
3. 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[]
4. 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. ### 32.6. 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. ### 32.7. 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 -
    <p>Hello <strong>World!</strong></p>
2. 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. ### 32.8. Badges in HTML Page Footers See the `[footer]` section in the AsciiDoc distribution `xhtml11.conf` configuration file. ### 32.9. Pretty Printing AsciiDoc Output If the indentation and layout of the `asciidoc(1)` output is not to your liking you can: 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. 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/ ### 32.10. 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. ### 32.11. 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. ### 32.12. 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. ### 32.13. 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[]
### 32.14. 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. ## 33. Glossary Block element An AsciiDoc block element is a document entity composed of one or more whole lines of text. 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. ## 34. Appendix A: Migration Notes ### 34.1. 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`.
| 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).
### 34.2. 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 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!`.
Table: Equivalent command-line syntax
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). ## 35. 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/`. 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. ## 36. 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.
| The safe mode is not designed to protect against unsafe AsciiDoc configuration files. Be especially careful when: Implementing filters. Implementing elements that don't escape special characters. Accepting configuration files from untrusted sources.
3. ## 37. Appendix D: Installing FOP on Windows Download latest FOP distribution from http://xml.apache.org/fop/. Unzip to `C:\bin`. Edit the distribution `fop.bat` file and put it in the search `PATH`:
       set LOCAL_FOP_HOME=C:\bin\fop-0.20.5\
6. Download the JIMI image processing library from http://java.sun.com/products/jimi/. Extract the `JimiProClasses.jar` library from the JIMI distribution and copy to the FOP `./lib` directory. Edit the distribution `fop.bat` file again and add the JIMI library to `LOCALCLASSPATH`:
       set LOCALCLASSPATH=%LOCALCLASSPATH%;%LIBDIR%\JimiProClasses.jar
7. You should now be able to run FOP from a DOS prompt — execute it without arguments to get a list of command options:
       > fop.bat
2. ## 38. Appendix E: Installing FOP on Linux Here's how I installed FOP on Fedora Core 1: Download latest FOP distribution from http://xml.apache.org/fop/. Install the FOP distribution:
       $ su
       # cd /usr/local/lib
       # unzip ~srackham/tmp/fop-0.20.5-bin.zip
       # cp /usr/local/lib/fop-0.20.5/fop.sh /usr/local/bin
       # chmod +x /usr/local/bin/fop.sh
3. Edit the FOP start script `fop.sh` adding this line to the start of the script:
       FOP_HOME=/usr/local/lib/fop-0.20.5
5. Download the JIMI image processing library from http://java.sun.com/products/jimi/. Extract the `JimiProClasses.jar` library from the JIMI distribution and copy to the FOP `lib` directory.
       # cp ~srackham/tmp/JimiProClasses.jar /usr/local/lib/fop-0.20.5/lib/
6. You should now be able to run FOP from a DOS prompt — execute it without arguments to get a list of command options:
       $ fop.sh
2. ## 39. Appendix F: Installing Java on Windows First check that Java is not already installed: Open a DOS Command Prompt window. Enter this command:
       java -version
You should see something like this:
    java version "1.4.2_01"
    Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_01-b06)
    Java HotSpot(TM) Client VM (build 1.4.2_01-b06, mixed mode)
If you don't Java is not installed and you need to: Download the Java Runtime (JRE) for Windows from http://java.sun.com. Install using the instructions on the download page. ## 40. Appendix G: Installing Java on Linux Check Java is not already installed by entering the following command:
    $ java -version
You should see something like this:
    java version "1.4.2_01"
    Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_01-b06)
    Java HotSpot(TM) Client VM (build 1.4.2_01-b06, mixed mode)
If it's not already set you will need to set the `JAVA_HOME` environment variable. For example on Kubuntu Breezy put the following line into `/etc/profile`:
    export JAVA_HOME=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/
- ## 41. Appendix H: Using AsciiDoc with non-English Languages AsciiDoc can process UTF-8 character sets but there are some things you need to be aware of: Admonition captions, example block title prefixes, table title prefixes and image block title prefixes default to English. You can customize these captions and prefixes with the `caption` attribute. Alternatively you could override the related AsciiDoc configuration file entries with a custom configuration file.
  | The `caption` attribute only applies if you are using the `xhtml11` or `html4` backends — if you are going the DocBook route you will need to configure the XSL Stylesheets for your language.
Some character sets display double-width characters (for example Japanese). As far as title underlines are concerned they should be treated as single character. If you think this looks untidy so you may prefer to use the single line title format. ## 42. Appendix I: ASCIIMathML Support 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 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.
| See the ASCIIMathML website for ASCIIMathML documentation and the latest version. If you use Mozilla you need to install the required math fonts. If you use Microsoft Internet Explorer 6 you need to install MathPlayer.
## 43. Appendix J: 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:
- ### 43.1. 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. Text formatting is not highlighted inside titles or attribute lists. Most escaped inline elements will be highlighted. Unterminated quotes are highlighted, for example `'tis` would be seen as the start of emphasized text. In this case work-around would be to comment out `asciidocEmphasized2` and use the (`asciidocEmphasized`) underscored for emphasis. As a damage control measure quoted patterns 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).
| Sometimes incorrect highlighting is caused by preceding lines that appear blank but contain white space characters.