path: root/MANUAL.txt

% Pandoc User's Guide
% John MacFarlane
% December 27, 2017

Synopsis
========

`pandoc` [*options*] [*input-file*]...

Description
===========

Pandoc is a [Haskell] library for converting from one markup format to
another, and a command-line tool that uses this library.

Pandoc can read [Markdown], [CommonMark], [PHP Markdown Extra],
[GitHub-Flavored Markdown], [MultiMarkdown], and (subsets of) [Textile],
[reStructuredText], [HTML], [LaTeX], [MediaWiki markup], [TWiki
markup], [TikiWiki markup], [Creole 1.0], [Haddock markup], [OPML],
[Emacs Org mode], [DocBook], [JATS], [Muse], [txt2tags], [Vimwiki],
[EPUB], [ODT], and [Word docx].

Pandoc can write plain text, [Markdown],
[CommonMark], [PHP Markdown Extra], [GitHub-Flavored Markdown],
[MultiMarkdown], [reStructuredText], [XHTML], [HTML5], [LaTeX]
\(including [`beamer`] slide shows\), [ConTeXt], [RTF], [OPML],
[DocBook], [JATS], [OpenDocument], [ODT], [Word docx], [GNU Texinfo],
[MediaWiki markup], [DokuWiki markup], [ZimWiki markup], [Haddock
markup], [EPUB] \(v2 or v3\), [FictionBook2], [Textile], [groff man],
[groff ms], [Emacs Org mode], [AsciiDoc], [InDesign ICML], [TEI
Simple], [Muse], [PowerPoint] slide shows and [Slidy], [Slideous],
[DZSlides], [reveal.js] or [S5] HTML slide shows. It can also produce
[PDF] output on systems where LaTeX, ConTeXt, `pdfroff`,
`wkhtmltopdf`, `prince`, or `weasyprint` is installed.

Pandoc's enhanced version of Markdown includes syntax for [tables],
[definition lists], [metadata blocks], [`Div` blocks][Extension:
`fenced_divs`], [footnotes] and [citations], embedded
[LaTeX][Extension: `raw_tex`] (including [math]), [Markdown inside HTML
block elements][Extension: `markdown_in_html_blocks`], and much more.
These enhancements, described further under [Pandoc's Markdown],
can be disabled using the `markdown_strict` format.

Pandoc has a modular design: it consists of a set of readers, which parse
text in a given format and produce a native representation of the document
(like an _abstract syntax tree_ or AST), and a set of writers, which convert
this native representation into a target format. Thus, adding an input
or output format requires only adding a reader or writer. Users can also
run custom [pandoc filters] to modify the intermediate AST.

Because pandoc's intermediate representation of a document is less
expressive than many of the formats it converts between, one should
not expect perfect conversions between every format and every other.
Pandoc attempts to preserve the structural elements of a document, but
not formatting details such as margin size.  And some document elements,
such as complex tables, may not fit into pandoc's simple document
model.  While conversions from pandoc's Markdown to all formats aspire
to be perfect, conversions from formats more expressive than pandoc's
Markdown can be expected to be lossy.

[Markdown]: http://daringfireball.net/projects/markdown/
[CommonMark]: http://commonmark.org
[PHP Markdown Extra]: https://michelf.ca/projects/php-markdown/extra/
[GitHub-Flavored Markdown]: https://help.github.com/articles/github-flavored-markdown/
[MultiMarkdown]: http://fletcherpenney.net/multimarkdown/
[reStructuredText]: http://docutils.sourceforge.net/docs/ref/rst/introduction.html
[S5]: http://meyerweb.com/eric/tools/s5/
[Slidy]: http://www.w3.org/Talks/Tools/Slidy/
[Slideous]: http://goessner.net/articles/slideous/
[HTML]: http://www.w3.org/html/
[HTML5]: http://www.w3.org/TR/html5/
[polyglot markup]: https://www.w3.org/TR/html-polyglot/
[XHTML]: http://www.w3.org/TR/xhtml1/
[LaTeX]: http://latex-project.org
[`beamer`]: https://ctan.org/pkg/beamer
[Beamer User's Guide]: http://ctan.math.utah.edu/ctan/tex-archive/macros/latex/contrib/beamer/doc/beameruserguide.pdf
[ConTeXt]: http://www.contextgarden.net/
[RTF]: http://en.wikipedia.org/wiki/Rich_Text_Format
[DocBook]: http://docbook.org
[JATS]: https://jats.nlm.nih.gov
[txt2tags]: http://txt2tags.org
[EPUB]: http://idpf.org/epub
[OPML]: http://dev.opml.org/spec2.html
[OpenDocument]: http://opendocument.xml.org
[ODT]: http://en.wikipedia.org/wiki/OpenDocument
[Textile]: http://redcloth.org/textile
[MediaWiki markup]: https://www.mediawiki.org/wiki/Help:Formatting
[DokuWiki markup]: https://www.dokuwiki.org/dokuwiki
[ZimWiki markup]: http://zim-wiki.org/manual/Help/Wiki_Syntax.html
[TWiki markup]: http://twiki.org/cgi-bin/view/TWiki/TextFormattingRules
[TikiWiki markup]: https://doc.tiki.org/Wiki-Syntax-Text#The_Markup_Language_Wiki-Syntax
[Haddock markup]: https://www.haskell.org/haddock/doc/html/ch03s08.html
[Creole 1.0]: http://www.wikicreole.org/wiki/Creole1.0
[groff man]: http://man7.org/linux/man-pages/man7/groff_man.7.html
[groff ms]: http://man7.org/linux/man-pages/man7/groff_ms.7.html
[Haskell]: https://www.haskell.org
[GNU Texinfo]: http://www.gnu.org/software/texinfo/
[Emacs Org mode]: http://orgmode.org
[AsciiDoc]: http://www.methods.co.nz/asciidoc/
[DZSlides]: http://paulrouget.com/dzslides/
[Word docx]: https://en.wikipedia.org/wiki/Office_Open_XML
[PDF]: https://www.adobe.com/pdf/
[reveal.js]: http://lab.hakim.se/reveal-js/
[FictionBook2]: http://www.fictionbook.org/index.php/Eng:XML_Schema_Fictionbook_2.1
[InDesign ICML]: https://www.adobe.com/content/dam/Adobe/en/devnet/indesign/cs55-docs/IDML/idml-specification.pdf
[TEI Simple]: https://github.com/TEIC/TEI-Simple
[Muse]: https://amusewiki.org/library/manual
[PowerPoint]: https://en.wikipedia.org/wiki/Microsoft_PowerPoint
[Vimwiki]: https://vimwiki.github.io

Using `pandoc`
--------------

If no *input-files* are specified, input is read from *stdin*.
Output goes to *stdout* by default. For output to a file,
use the `-o` option:

    pandoc -o output.html input.txt

By default, pandoc produces a document fragment. To produce a standalone
document (e.g. a valid HTML file including `<head>` and `<body>`),
use the `-s` or `--standalone` flag:

    pandoc -s -o output.html input.txt

For more information on how standalone documents are produced, see
[Templates] below.

If multiple input files are given, `pandoc` will concatenate them all (with
blank lines between them) before parsing. (Use `--file-scope` to parse files
individually.)

Specifying formats
------------------

The format of the input and output can be specified explicitly using
command-line options.  The input format can be specified using the
`-f/--from` option, the output format using the `-t/--to` option.
Thus, to convert `hello.txt` from Markdown to LaTeX, you could type:

    pandoc -f markdown -t latex hello.txt

To convert `hello.html` from HTML to Markdown:

    pandoc -f html -t markdown hello.html

Supported input and output formats are listed below under [Options]
(see `-f` for input formats and `-t` for output formats).  You
can also use `pandoc --list-input-formats` and
`pandoc --list-output-formats` to print lists of supported
formats.

If the input or output format is not specified explicitly, `pandoc`
will attempt to guess it from the extensions of the filenames.
Thus, for example,

    pandoc -o hello.tex hello.txt

will convert `hello.txt` from Markdown to LaTeX.  If no output file
is specified (so that output goes to *stdout*), or if the output file's
extension is unknown, the output format will default to HTML.
If no input file is specified (so that input comes from *stdin*), or
if the input files' extensions are unknown, the input format will
be assumed to be Markdown.

Character encoding
------------------

Pandoc uses the UTF-8 character encoding for both input and output.
If your local character encoding is not UTF-8, you
should pipe input and output through [`iconv`]:

    iconv -t utf-8 input.txt | pandoc | iconv -f utf-8

Note that in some output formats (such as HTML, LaTeX, ConTeXt,
RTF, OPML, DocBook, and Texinfo), information about
the character encoding is included in the document header, which
will only be included if you use the `-s/--standalone` option.

[`iconv`]: http://www.gnu.org/software/libiconv/

Creating a PDF
--------------

To produce a PDF, specify an output file with a `.pdf` extension:

    pandoc test.txt -o test.pdf

By default, pandoc will use LaTeX to create the PDF, which requires
that a LaTeX engine be installed (see `--pdf-engine` below).

Alternatively, pandoc can use [ConTeXt], `pdfroff`, or any of the
following HTML/CSS-to-PDF-engines, to create a PDF: [`wkhtmltopdf`],
[`weasyprint`] or [`prince`].
To do this, specify an output file with a `.pdf` extension, as before,
but add the `--pdf-engine` option or `-t context`, `-t html`, or `-t ms`
to the command line (`-t html` defaults to `--pdf-engine=wkhtmltopdf`).

PDF output can be controlled using [variables for LaTeX] (if
LaTeX is used) and [variables for ConTeXt] (if ConTeXt is used).
When using an HTML/CSS-to-PDF-engine, `--css` affects the output.
If `wkhtmltopdf` is used, then the variables `margin-left`,
`margin-right`, `margin-top`, `margin-bottom`, and `papersize`
will affect the output.

To debug the PDF creation, it can be useful to look at the intermediate
representation: instead of `-o test.pdf`, use for example `-s -o test.tex`
to output the generated LaTeX. You can then test it with `pdflatex test.tex`.

When using LaTeX, the following packages need to be available
(they are included with all recent versions of [TeX Live]):
[`amsfonts`], [`amsmath`], [`lm`], [`unicode-math`],
[`ifxetex`], [`ifluatex`], [`listings`] (if the
`--listings` option is used), [`fancyvrb`], [`longtable`],
[`booktabs`], [`graphicx`] and [`grffile`] (if the document
contains images), [`hyperref`], [`xcolor`] (with `colorlinks`),
[`ulem`], [`geometry`] (with the `geometry` variable set),
[`setspace`] (with `linestretch`), and
[`babel`] (with `lang`).  The use of `xelatex` or `lualatex` as
the LaTeX engine requires [`fontspec`].  `xelatex` uses
[`polyglossia`] (with `lang`), [`xecjk`], and [`bidi`] (with the
`dir` variable set). If the `mathspec` variable is set,
`xelatex` will use [`mathspec`] instead of [`unicode-math`].
The [`upquote`] and [`microtype`] packages are used if
available, and [`csquotes`] will be used for [typography]
if added to the template or included in any header file. The
[`natbib`], [`biblatex`], [`bibtex`], and [`biber`] packages can
optionally be used for [citation rendering].

[`amsfonts`]: https://ctan.org/pkg/amsfonts
[`amsmath`]: https://ctan.org/pkg/amsmath
[`lm`]: https://ctan.org/pkg/lm
[`ifxetex`]: https://ctan.org/pkg/ifxetex
[`ifluatex`]: https://ctan.org/pkg/ifluatex
[`listings`]: https://ctan.org/pkg/listings
[`fancyvrb`]: https://ctan.org/pkg/fancyvrb
[`longtable`]: https://ctan.org/pkg/longtable
[`booktabs`]: https://ctan.org/pkg/booktabs
[`graphicx`]: https://ctan.org/pkg/graphicx
[`grffile`]: https://ctan.org/pkg/grffile
[`geometry`]: https://ctan.org/pkg/geometry
[`setspace`]: https://ctan.org/pkg/setspace
[`xecjk`]: https://ctan.org/pkg/xecjk
[`hyperref`]: https://ctan.org/pkg/hyperref
[`ulem`]: https://ctan.org/pkg/ulem
[`babel`]: https://ctan.org/pkg/babel
[`bidi`]: https://ctan.org/pkg/bidi
[`mathspec`]: https://ctan.org/pkg/mathspec
[`unicode-math`]: https://ctan.org/pkg/unicode-math
[`polyglossia`]: https://ctan.org/pkg/polyglossia
[`fontspec`]: https://ctan.org/pkg/fontspec
[`upquote`]: https://ctan.org/pkg/upquote
[`microtype`]: https://ctan.org/pkg/microtype
[`csquotes`]: https://ctan.org/pkg/csquotes
[`natbib`]: https://ctan.org/pkg/natbib
[`biblatex`]: https://ctan.org/pkg/biblatex
[`bibtex`]: https://ctan.org/pkg/bibtex
[`biber`]: https://ctan.org/pkg/biber
[TeX Live]: http://www.tug.org/texlive/
[`wkhtmltopdf`]: https://wkhtmltopdf.org
[`weasyprint`]: http://weasyprint.org
[`prince`]: https://www.princexml.com/

Reading from the Web
--------------------

Instead of an input file, an absolute URI may be given.  In this case
pandoc will fetch the content using HTTP:

    pandoc -f html -t markdown http://www.fsf.org

It is possible to supply a custom User-Agent string or other
header when requesting a document from a URL:

    pandoc -f html -t markdown --request-header User-Agent:"Mozilla/5.0" \
      http://www.fsf.org

Options
=======

General options
---------------

`-f` *FORMAT*, `-r` *FORMAT*, `--from=`*FORMAT*, `--read=`*FORMAT*

:   Specify input format.  *FORMAT* can be `native` (native Haskell),
    `json` (JSON version of native AST), `markdown` (pandoc's
    extended Markdown), `markdown_strict` (original unextended
    Markdown), `markdown_phpextra` (PHP Markdown Extra),
    `markdown_mmd` (MultiMarkdown), `gfm` (GitHub-Flavored Markdown),
    `commonmark` (CommonMark Markdown), `textile` (Textile), `rst`
    (reStructuredText), `html` (HTML), `docbook` (DocBook), `t2t`
    (txt2tags), `docx` (docx), `odt` (ODT), `epub` (EPUB), `opml` (OPML),
    `org` (Emacs Org mode), `mediawiki` (MediaWiki markup), `twiki` (TWiki
    markup), `tikiwiki` (TikiWiki markup), `creole` (Creole 1.0),
    `haddock` (Haddock markup), or `latex` (LaTeX).
    (`markdown_github` provides deprecated and less accurate support
    for Github-Flavored Markdown; please use `gfm` instead, unless you
    need to use extensions other than `smart`.)
    Extensions can be individually enabled or disabled by
    appending `+EXTENSION` or `-EXTENSION` to the format name.
    See [Extensions] below, for a list of extensions and
    their names.  See `--list-input-formats` and `--list-extensions`,
    below.

`-t` *FORMAT*, `-w` *FORMAT*, `--to=`*FORMAT*, `--write=`*FORMAT*

:   Specify output format.  *FORMAT* can be `native` (native Haskell),
    `json` (JSON version of native AST), `plain` (plain text),
    `markdown` (pandoc's extended Markdown), `markdown_strict`
    (original unextended Markdown), `markdown_phpextra` (PHP Markdown
    Extra), `markdown_mmd` (MultiMarkdown), `gfm` (GitHub-Flavored
    Markdown), `commonmark` (CommonMark Markdown), `rst`
    (reStructuredText), `html4` (XHTML 1.0 Transitional), `html` or
    `html5` (HTML5/XHTML [polyglot markup]), `latex` (LaTeX), `beamer`
    (LaTeX beamer slide show), `context` (ConTeXt), `man` (groff man),
    `mediawiki` (MediaWiki markup), `dokuwiki` (DokuWiki markup),
    `zimwiki` (ZimWiki markup), `textile` (Textile), `org` (Emacs Org
    mode), `texinfo` (GNU Texinfo), `opml` (OPML), `docbook` or
    `docbook4` (DocBook 4), `docbook5` (DocBook 5), `jats` (JATS XML),
    `opendocument` (OpenDocument), `odt` (OpenOffice text document),
    `docx` (Word docx), `haddock` (Haddock markup), `rtf` (rich text
    format), `epub2` (EPUB v2 book), `epub` or `epub3` (EPUB v3),
    `fb2` (FictionBook2 e-book), `asciidoc` (AsciiDoc), `icml`
    (InDesign ICML), `tei` (TEI Simple), `slidy` (Slidy HTML and
    JavaScript slide show), `slideous` (Slideous HTML and JavaScript
    slide show), `dzslides` (DZSlides HTML5 + JavaScript slide show),
    `revealjs` (reveal.js HTML5 + JavaScript slide show), `s5` (S5
    HTML and JavaScript slide show), `pptx` (PowerPoint slide show) or
    the path of a custom lua writer (see [Custom writers],
    below). (`markdown_github` provides deprecated and less accurate
    support for Github-Flavored Markdown; please use `gfm` instead,
    unless you use extensions that do not work with `gfm`.) Note that
    `odt`, `docx`, and `epub` output will not be directed to *stdout*
    unless forced with `-o -`. Extensions can be individually enabled or
    disabled by appending `+EXTENSION` or `-EXTENSION` to the format
    name.  See [Extensions] below, for a list of extensions and their
    names.  See `--list-output-formats` and `--list-extensions`, below.

`-o` *FILE*, `--output=`*FILE*

:   Write output to *FILE* instead of *stdout*.  If *FILE* is
    `-`, output will go to *stdout*, even if a non-textual format
    (`docx`, `odt`, `epub2`, `epub3`) is specified.

`--data-dir=`*DIRECTORY*

:   Specify the user data directory to search for pandoc data files.
    If this option is not specified, the default user data directory
    will be used.  This is, in UNIX:

        $HOME/.pandoc

    in Windows XP:

        C:\Documents And Settings\USERNAME\Application Data\pandoc

    and in Windows Vista or later:

        C:\Users\USERNAME\AppData\Roaming\pandoc

    You can find the default user data directory on your system by
    looking at the output of `pandoc --version`.
    A `reference.odt`, `reference.docx`, `epub.css`, `templates`,
    `slidy`, `slideous`, or `s5` directory
    placed in this directory will override pandoc's normal defaults.

`--bash-completion`

:   Generate a bash completion script.  To enable bash completion
    with pandoc, add this to your `.bashrc`:

         eval "$(pandoc --bash-completion)"

`--verbose`

:   Give verbose debugging output.  Currently this only has an effect
    with PDF output.

`--quiet`

:   Suppress warning messages.

`--fail-if-warnings`

:   Exit with error status if there are any warnings.

`--log=`*FILE*

:   Write log messages in machine-readable JSON format to
    *FILE*.  All messages above DEBUG level will be written,
    regardless of verbosity settings (`--verbose`, `--quiet`).

`--list-input-formats`

:   List supported input formats, one per line.

`--list-output-formats`

:   List supported output formats, one per line.

`--list-extensions`[`=`*FORMAT*]

:   List supported extensions, one per line, preceded
    by a `+` or `-` indicating whether it is enabled by default
    in *FORMAT*. If *FORMAT* is not specified, defaults for
    pandoc's Markdown are given.

`--list-highlight-languages`

:   List supported languages for syntax highlighting, one per
    line.

`--list-highlight-styles`

:   List supported styles for syntax highlighting, one per line.
    See `--highlight-style`.

`-v`, `--version`

:   Print version.

`-h`, `--help`

:   Show usage message.

Reader options
--------------

`--base-header-level=`*NUMBER*

:   Specify the base level for headers (defaults to 1).

`--strip-empty-paragraphs`

:   *Deprecated.  Use the `+empty_paragraphs` extension instead.*
    Ignore paragraphs with no content.  This option is useful
    for converting word processing documents where users have
    used empty paragraphs to create inter-paragraph space.

`--indented-code-classes=`*CLASSES*

:   Specify classes to use for indented code blocks--for example,
    `perl,numberLines` or `haskell`. Multiple classes may be separated
    by spaces or commas.

`--default-image-extension=`*EXTENSION*

:   Specify a default extension to use when image paths/URLs have no
    extension.  This allows you to use the same source for formats that
    require different kinds of images.  Currently this option only affects
    the Markdown and LaTeX readers.

`--file-scope`

:   Parse each file individually before combining for multifile
    documents. This will allow footnotes in different files with the
    same identifiers to work as expected. If this option is set,
    footnotes and links will not work across files. Reading binary
    files (docx, odt, epub) implies `--file-scope`.

`--filter=`*PROGRAM*

:   Specify an executable to be used as a filter transforming the
    pandoc AST after the input is parsed and before the output is
    written.  The executable should read JSON from stdin and write
    JSON to stdout.  The JSON must be formatted like  pandoc's own
    JSON input and output.  The name of the output format will be
    passed to the filter as the first argument.  Hence,

        pandoc --filter ./caps.py -t latex

    is equivalent to

        pandoc -t json | ./caps.py latex | pandoc -f json -t latex

    The latter form may be useful for debugging filters.

    Filters may be written in any language.  `Text.Pandoc.JSON`
    exports `toJSONFilter` to facilitate writing filters in Haskell.
    Those who would prefer to write filters in python can use the
    module [`pandocfilters`], installable from PyPI. There are also
    pandoc filter libraries in [PHP], [perl], and
    [JavaScript/node.js].

    In order of preference, pandoc will look for filters in

     1. a specified full or relative path (executable or
     non-executable)

     2. `$DATADIR/filters` (executable or non-executable)
     where `$DATADIR` is the user data directory (see
     `--data-dir`, above).

     3. `$PATH` (executable only)

    Filters and lua-filters are applied in the order specified
    on the command line.

`--lua-filter=`*SCRIPT*

:   Transform the document in a similar fashion as JSON filters (see
    `--filter`), but use pandoc's build-in lua filtering system.  The given
    lua script is expected to return a list of lua filters which will be
    applied in order.  Each lua filter must contain element-transforming
    functions indexed by the name of the AST element on which the filter
    function should be applied.

    The `pandoc` lua module provides helper functions for element
    creation.  It is always loaded into the script's lua environment.

    The following is an example lua script for macro-expansion:

        function expand_hello_world(inline)
          if inline.c == '{{helloworld}}' then
            return pandoc.Emph{ pandoc.Str "Hello, World" }
          else
            return inline
          end
        end

        return {{Str = expand_hello_world}}


`-M` *KEY*[`=`*VAL*], `--metadata=`*KEY*[`:`*VAL*]

:   Set the metadata field *KEY* to the value *VAL*.  A value specified
    on the command line overrides a value specified in the document.
    Values will be parsed as YAML boolean or string values. If no value is
    specified, the value will be treated as Boolean true.  Like
    `--variable`, `--metadata` causes template variables to be set.
    But unlike `--variable`, `--metadata` affects the metadata of the
    underlying document (which is accessible from filters and may be
    printed in some output formats).

`-p`, `--preserve-tabs`

:   Preserve tabs instead of converting them to spaces (the default).
    Note that this will only affect tabs in literal code spans and code
    blocks; tabs in regular text will be treated as spaces.

`--tab-stop=`*NUMBER*

:   Specify the number of spaces per tab (default is 4).

`--track-changes=accept`|`reject`|`all`

:   Specifies what to do with insertions, deletions, and comments
    produced by the MS Word "Track Changes" feature.  `accept` (the
    default), inserts all insertions, and ignores all
    deletions. `reject` inserts all deletions and ignores
    insertions. Both `accept` and `reject` ignore comments. `all` puts
    in insertions, deletions, and comments, wrapped in spans with
    `insertion`, `deletion`, `comment-start`, and `comment-end`
    classes, respectively. The author and time of change is
    included. `all` is useful for scripting: only accepting changes
    from a certain reviewer, say, or before a certain date. If a
    paragraph is inserted or deleted, `track-changes=all` produces a
    span with the class `paragraph-insertion`/`paragraph-deletion`
    before the affected paragraph break. This option only affects the
    docx reader.

`--extract-media=`*DIR*

:   Extract images and other media contained in or linked from
    the source document to the path *DIR*, creating it if
    necessary, and adjust the images references in the document
    so they point to the extracted files.  If the source format is
    a binary container (docx, epub, or odt), the media is
    extracted from the container and the original
    filenames are used. Otherwise the media is read from the
    file system or downloaded, and new filenames are constructed
    based on SHA1 hashes of the contents.

`--abbreviations=`*FILE*

:   Specifies a custom abbreviations file, with abbreviations
    one to a line.  If this option is not specified, pandoc will
    read the data file `abbreviations` from the user data
    directory or fall back on a system default.  To see the
    system default, use
    `pandoc --print-default-data-file=abbreviations`.  The only
    use pandoc makes of this list is in the Markdown reader.
    Strings ending in a period that are found in this list will
    be followed by a nonbreaking space, so that the period will
    not produce sentence-ending space in formats like LaTeX.

[`pandocfilters`]: https://github.com/jgm/pandocfilters
[PHP]: https://github.com/vinai/pandocfilters-php
[perl]: https://metacpan.org/pod/Pandoc::Filter
[JavaScript/node.js]: https://github.com/mvhenderson/pandoc-filter-node

General writer options
----------------------

`-s`, `--standalone`

:   Produce output with an appropriate header and footer (e.g. a
    standalone HTML, LaTeX, TEI, or RTF file, not a fragment).  This option
    is set automatically for `pdf`, `epub`, `epub3`, `fb2`, `docx`, and `odt`
    output.

`--template=`*FILE*

:   Use *FILE* as a custom template for the generated document. Implies
    `--standalone`. See [Templates], below, for a description
    of template syntax. If no extension is specified, an extension
    corresponding to the writer will be added, so that `--template=special`
    looks for `special.html` for HTML output.  If the template is not
    found, pandoc will search for it in the `templates` subdirectory of
    the user data directory (see `--data-dir`). If this option is not used,
    a default template appropriate for the output format will be used (see
    `-D/--print-default-template`).

`-V` *KEY*[`=`*VAL*], `--variable=`*KEY*[`:`*VAL*]

:   Set the template variable *KEY* to the value *VAL* when rendering the
    document in standalone mode. This is generally only useful when the
    `--template` option is used to specify a custom template, since
    pandoc automatically sets the variables used in the default
    templates.  If no *VAL* is specified, the key will be given the
    value `true`.

`-D` *FORMAT*, `--print-default-template=`*FORMAT*

:   Print the system default template for an output *FORMAT*. (See `-t`
    for a list of possible *FORMAT*s.)  Templates in the user data
    directory are ignored.

`--print-default-data-file=`*FILE*

:   Print a system default data file.  Files in the user data directory
    are ignored.

`--eol=crlf`|`lf`|`native`

:   Manually specify line endings: `crlf` (Windows), `lf`
    (macOS/Linux/UNIX), or `native` (line endings appropriate
    to the OS on which pandoc is being run).  The default is
    `native`.

`--dpi`=*NUMBER*

:   Specify the dpi (dots per inch) value for conversion from pixels
    to inch/centimeters and vice versa. The default is 96dpi.
    Technically, the correct term would be ppi (pixels per inch).

`--wrap=auto`|`none`|`preserve`

:   Determine how text is wrapped in the output (the source
    code, not the rendered version).  With `auto` (the default),
    pandoc will attempt to wrap lines to the column width specified by
    `--columns` (default 72).  With `none`, pandoc will not wrap
    lines at all.  With `preserve`, pandoc will attempt to
    preserve the wrapping from the source document (that is,
    where there are nonsemantic newlines in the source, there
    will be nonsemantic newlines in the output as well).
    Automatic wrapping does not currently work in HTML output.

`--columns=`*NUMBER*

:   Specify length of lines in characters.  This affects text wrapping
    in the generated source code (see `--wrap`).  It also affects
    calculation of column widths for plain text tables (see [Tables] below).

`--toc`, `--table-of-contents`

:   Include an automatically generated table of contents (or, in
    the case of `latex`, `context`, `docx`, `odt`,
    `opendocument`, `rst`, or `ms`, an instruction to create
    one) in the output document. This option has no effect on
    `man`, `docbook4`, `docbook5`, or `jats` output.

`--toc-depth=`*NUMBER*

:   Specify the number of section levels to include in the table
    of contents.  The default is 3 (which means that level 1, 2, and 3
    headers will be listed in the contents).

`--strip-comments`

:   Strip out HTML comments in the Markdown or Textile source,
    rather than passing them on to Markdown, Textile or HTML
    output as raw HTML.  This does not apply to HTML comments
    inside raw HTML blocks when the `markdown_in_html_blocks`
    extension is not set.

`--no-highlight`

:   Disables syntax highlighting for code blocks and inlines, even when
    a language attribute is given.

`--highlight-style=`*STYLE*|*FILE*

:   Specifies the coloring style to be used in highlighted source code.
    Options are `pygments` (the default), `kate`, `monochrome`,
    `breezeDark`, `espresso`, `zenburn`, `haddock`, and `tango`.
    For more information on syntax highlighting in pandoc, see
    [Syntax highlighting], below.  See also
    `--list-highlight-styles`.

    Instead of a *STYLE* name, a JSON file with extension
    `.theme` may be supplied.  This will be parsed as a KDE
    syntax highlighting theme and (if valid) used as the
    highlighting style.

    To generate the JSON version of an existing style,
    use `--print-highlight-style`.

`--print-highlight-style=`*STYLE*|*FILE*

:   Prints a JSON version of a highlighting style, which can
    be modified, saved with a `.theme` extension, and used
    with `--highlight-style`.

`--syntax-definition=`*FILE*

:   Instructs pandoc to load a KDE XML syntax definition file,
    which will be used for syntax highlighting of appropriately
    marked code blocks.  This can be used to add support for
    new languages or to use altered syntax definitions for
    existing languages.

`-H` *FILE*, `--include-in-header=`*FILE*

:   Include contents of *FILE*, verbatim, at the end of the header.
    This can be used, for example, to include special
    CSS or JavaScript in HTML documents.  This option can be used
    repeatedly to include multiple files in the header.  They will be
    included in the order specified.  Implies `--standalone`.

`-B` *FILE*, `--include-before-body=`*FILE*

:   Include contents of *FILE*, verbatim, at the beginning of the
    document body (e.g. after the `<body>` tag in HTML, or the
    `\begin{document}` command in LaTeX). This can be used to include
    navigation bars or banners in HTML documents. This option can be
    used repeatedly to include multiple files. They will be included in
    the order specified.  Implies `--standalone`.

`-A` *FILE*, `--include-after-body=`*FILE*

:   Include contents of *FILE*, verbatim, at the end of the document
    body (before the `</body>` tag in HTML, or the
    `\end{document}` command in LaTeX). This option can be used
    repeatedly to include multiple files. They will be included in the
    order specified.  Implies `--standalone`.

`--resource-path=`*SEARCHPATH*

:   List of paths to search for images and other resources.
    The paths should be separated by `:` on Linux, UNIX, and
    macOS systems, and by `;` on Windows.  If `--resource-path`
    is not specified, the default resource path is the working
    directory. Note that, if `--resource-path` is specified,
    the working directory must be explicitly listed or it
    will not be searched.  For example:
    `--resource-path=.:test` will search the working directory
    and the `test` subdirectory, in that order.

`--request-header=`*NAME*`:`*VAL*

:   Set the request header *NAME* to the value *VAL* when making
    HTTP requests (for example, when a URL is given on the
    command line, or when resources used in a document must be
    downloaded).

Options affecting specific writers
----------------------------------

`--self-contained`

:   Produce a standalone HTML file with no external dependencies, using
    `data:` URIs to incorporate the contents of linked scripts, stylesheets,
    images, and videos. The resulting file should be "self-contained,"
    in the sense that it needs no external files and no net access to be
    displayed properly by a browser. This option works only with HTML output
    formats, including `html4`, `html5`, `html+lhs`, `html5+lhs`, `s5`,
    `slidy`, `slideous`, `dzslides`, and `revealjs`. Scripts, images, and
    stylesheets at absolute URLs will be downloaded; those at relative URLs
    will be sought relative to the working directory (if the first source
    file is local) or relative to the base URL (if the first source
    file is remote).  Elements with the attribute
    `data-external="1"` will be left alone; the documents they
    link to will not be incorporated in the document.
    Limitation: resources that are loaded dynamically through
    JavaScript cannot be incorporated; as a result,
    `--self-contained` does not work with `--mathjax`, and some
    advanced features (e.g.  zoom or speaker notes) may not work
    in an offline "self-contained" `reveal.js` slide show.

`--html-q-tags`

:   Use `<q>` tags for quotes in HTML.

`--ascii`

:   Use only ASCII characters in output.  Currently supported only for
    HTML and DocBook output (which uses numerical entities instead of
    UTF-8 when this option is selected).

`--reference-links`

:   Use reference-style links, rather than inline links, in writing Markdown
    or reStructuredText.  By default inline links are used.  The
    placement of link references is affected by the
    `--reference-location` option.

`--reference-location = block`|`section`|`document`

:   Specify whether footnotes (and references, if `reference-links` is
    set) are placed at the end of the current (top-level) block, the
    current section, or the document. The default is
    `document`. Currently only affects the markdown writer.

`--atx-headers`

:   Use ATX-style headers in Markdown and AsciiDoc output. The default is
    to use setext-style headers for levels 1-2, and then ATX headers.
    (Note: for `gfm` output, ATX headers are always used.)

`--top-level-division=[default|section|chapter|part]`

:   Treat top-level headers as the given division type in LaTeX, ConTeXt,
    DocBook, and  TEI output. The hierarchy order is part, chapter, then section;
    all headers are shifted such that the top-level header becomes the specified
    type. The default behavior is to determine the best division type via
    heuristics: unless other conditions apply, `section` is chosen. When the
    LaTeX document class is set to `report`, `book`, or `memoir` (unless the
    `article` option is specified), `chapter` is implied as the setting for this
    option. If `beamer` is the output format, specifying either `chapter` or
    `part` will cause top-level headers to become `\part{..}`, while
    second-level headers remain as their default type.

`-N`, `--number-sections`

:   Number section headings in LaTeX, ConTeXt, HTML, or EPUB output.
    By default, sections are not numbered.  Sections with class
    `unnumbered` will never be numbered, even if `--number-sections`
    is specified.

`--number-offset=`*NUMBER*[`,`*NUMBER*`,`*...*]

:   Offset for section headings in HTML output (ignored in other
    output formats).  The first number is added to the section number for
    top-level headers, the second for second-level headers, and so on.
    So, for example, if you want the first top-level header in your
    document to be numbered "6", specify `--number-offset=5`.
    If your document starts with a level-2 header which you want to
    be numbered "1.5", specify `--number-offset=1,4`.
    Offsets are 0 by default.  Implies `--number-sections`.

`--listings`

:   Use the [`listings`] package for LaTeX code blocks

`-i`, `--incremental`

:   Make list items in slide shows display incrementally (one by one).
    The default is for lists to be displayed all at once.

`--slide-level=`*NUMBER*

:   Specifies that headers with the specified level create
    slides (for `beamer`, `s5`, `slidy`, `slideous`, `dzslides`).  Headers
    above this level in the hierarchy are used to divide the
    slide show into sections; headers below this level create
    subheads within a slide.  Note that content that is
    not contained under slide-level headers will not appear in
    the slide show.  The default is to set the slide level based
    on the contents of the document; see [Structuring the slide
    show].

`--section-divs`

:   Wrap sections in `<section>` tags (or `<div>` tags for `html4`),
    and attach identifiers to the enclosing `<section>` (or `<div>`)
    rather than the header itself. See
    [Header identifiers], below.

`--email-obfuscation=none`|`javascript`|`references`

:   Specify a method for obfuscating `mailto:` links in HTML documents.
    `none` leaves `mailto:` links as they are.  `javascript` obfuscates
    them using JavaScript. `references` obfuscates them by printing their
    letters as decimal or hexadecimal character references.  The default
    is `none`.

`--id-prefix=`*STRING*

:   Specify a prefix to be added to all identifiers and internal links
    in HTML and DocBook output, and to footnote numbers in Markdown
    and Haddock output. This is useful for preventing duplicate
    identifiers when generating fragments to be included in other pages.

`-T` *STRING*, `--title-prefix=`*STRING*

:   Specify *STRING* as a prefix at the beginning of the title
    that appears in the HTML header (but not in the title as it
    appears at the beginning of the HTML body).  Implies
    `--standalone`.

`-c` *URL*, `--css=`*URL*

:   Link to a CSS style sheet. This option can be used repeatedly to
    include multiple files. They will be included in the order specified.

    A stylesheet is required for generating EPUB.  If none is
    provided using this option (or the `stylesheet` metadata
    field), pandoc will look for a file `epub.css` in the
    user data directory (see `--data-dir`).  If it is not
    found there, sensible defaults will be used.

`--reference-doc=`*FILE*

:   Use the specified file as a style reference in producing a
    docx or ODT file.

    Docx

    :   For best results, the reference docx should be a modified
        version of a docx file produced using pandoc.  The contents
        of the reference docx are ignored, but its stylesheets and
        document properties (including margins, page size, header,
        and footer) are used in the new docx. If no reference docx
        is specified on the command line, pandoc will look for a
        file `reference.docx` in the user data directory (see
        `--data-dir`). If this is not found either, sensible
        defaults will be used.

        To produce a custom `reference.docx`, first get a copy of
        the default `reference.docx`: `pandoc
        --print-default-data-file reference.docx >
        custom-reference.docx`.  Then open `custom-reference.docx`
        in Word, modify the styles as you wish, and save the file.
        For best results, do not make changes to this file other
        than modifying the styles used by pandoc: [paragraph]
        Normal, Body Text, First Paragraph, Compact, Title,
        Subtitle, Author, Date, Abstract, Bibliography, Heading 1,
        Heading 2, Heading 3, Heading 4, Heading 5, Heading 6,
        Heading 7, Heading 8, Heading 9, Block Text, Footnote Text,
        Definition Term, Definition, Caption, Table Caption,
        Image Caption, Figure, Captioned Figure, TOC Heading;
        [character] Default Paragraph Font, Body Text Char,
        Verbatim Char, Footnote Reference, Hyperlink; [table]
        Table.

    ODT

    :   For best results, the reference ODT should be a modified
        version of an ODT produced using pandoc.  The contents of
        the reference ODT are ignored, but its stylesheets are used
        in the new ODT. If no reference ODT is specified on the
        command line, pandoc will look for a file `reference.odt` in
        the user data directory (see `--data-dir`). If this is not
        found either, sensible defaults will be used.

        To produce a custom `reference.odt`, first get a copy of
        the default `reference.odt`: `pandoc
        --print-default-data-file reference.odt >
        custom-reference.odt`.  Then open `custom-reference.odt` in
        LibreOffice, modify the styles as you wish, and save the
        file.

`--epub-cover-image=`*FILE*

:   Use the specified image as the EPUB cover.  It is recommended
    that the image be less than 1000px in width and height. Note that
    in a Markdown source document you can also specify `cover-image`
    in a YAML metadata block (see [EPUB Metadata], below).

`--epub-metadata=`*FILE*

:   Look in the specified XML file for metadata for the EPUB.
    The file should contain a series of [Dublin Core elements].
    For example:

         <dc:rights>Creative Commons</dc:rights>
         <dc:language>es-AR</dc:language>

    By default, pandoc will include the following metadata elements:
    `<dc:title>` (from the document title), `<dc:creator>` (from the
    document authors), `<dc:date>` (from the document date, which should
    be in [ISO 8601 format]), `<dc:language>` (from the `lang`
    variable, or, if is not set, the locale), and `<dc:identifier
    id="BookId">` (a randomly generated UUID). Any of these may be
    overridden by elements in the metadata file.

    Note: if the source document is Markdown, a YAML metadata block
    in the document can be used instead.  See below under
    [EPUB Metadata].

`--epub-embed-font=`*FILE*

:   Embed the specified font in the EPUB. This option can be repeated
    to embed multiple fonts.  Wildcards can also be used: for example,
    `DejaVuSans-*.ttf`.  However, if you use wildcards on the command
    line, be sure to escape them or put the whole filename in single quotes,
    to prevent them from being interpreted by the shell. To use the
    embedded fonts, you will need to add declarations like the following
    to your CSS (see `--css`):

        @font-face {
        font-family: DejaVuSans;
        font-style: normal;
        font-weight: normal;
        src:url("DejaVuSans-Regular.ttf");
        }
        @font-face {
        font-family: DejaVuSans;
        font-style: normal;
        font-weight: bold;
        src:url("DejaVuSans-Bold.ttf");
        }
        @font-face {
        font-family: DejaVuSans;
        font-style: italic;
        font-weight: normal;
        src:url("DejaVuSans-Oblique.ttf");
        }
        @font-face {
        font-family: DejaVuSans;
        font-style: italic;
        font-weight: bold;
        src:url("DejaVuSans-BoldOblique.ttf");
        }
        body { font-family: "DejaVuSans"; }

`--epub-chapter-level=`*NUMBER*

:   Specify the header level at which to split the EPUB into separate
    "chapter" files. The default is to split into chapters at level 1
    headers. This option only affects the internal composition of the
    EPUB, not the way chapters and sections are displayed to users. Some
    readers may be slow if the chapter files are too large, so for large
    documents with few level 1 headers, one might want to use a chapter
    level of 2 or 3.

`--epub-subdirectory=`*DIRNAME*

:   Specify the subdirectory in the OCF container that is to hold
    the EPUB-specific contents.  The default is `EPUB`.  To put
    the EPUB contents in the top level, use an empty string.

`--pdf-engine=pdflatex`|`lualatex`|`xelatex`|`wkhtmltopdf`|`weasyprint`|`prince`|`context`|`pdfroff`

:   Use the specified engine when producing PDF output.
    The default is `pdflatex`.  If the engine is not in your PATH,
    the full path of the engine may be specified here.

`--pdf-engine-opt=`*STRING*

:   Use the given string as a command-line argument to the `pdf-engine`.
    If used multiple times, the arguments are provided with spaces between
    them. Note that no check for duplicate options is done.

[Dublin Core elements]: http://dublincore.org/documents/dces/
[ISO 8601 format]: http://www.w3.org/TR/NOTE-datetime

Citation rendering
------------------

`--bibliography=`*FILE*

:   Set the `bibliography` field in the document's metadata to *FILE*,
    overriding any value set in the metadata, and process citations
    using `pandoc-citeproc`. (This is equivalent to
    `--metadata bibliography=FILE --filter pandoc-citeproc`.)
    If `--natbib` or `--biblatex` is also supplied, `pandoc-citeproc` is not
    used, making this equivalent to `--metadata bibliography=FILE`.
    If you supply this argument multiple times, each *FILE* will be added
    to bibliography.

`--csl=`*FILE*

:   Set the `csl` field in the document's metadata to *FILE*,
    overriding any value set in the metadata.  (This is equivalent to
    `--metadata csl=FILE`.)
    This option is only relevant with `pandoc-citeproc`.

`--citation-abbreviations=`*FILE*

:   Set the `citation-abbreviations` field in the document's metadata to
    *FILE*, overriding any value set in the metadata.  (This is equivalent to
    `--metadata citation-abbreviations=FILE`.)
    This option is only relevant with `pandoc-citeproc`.

`--natbib`

:   Use [`natbib`] for citations in LaTeX output.  This option is not for use
    with the `pandoc-citeproc` filter or with PDF output.  It is intended for
    use in producing a LaTeX file that can be processed with [`bibtex`].

`--biblatex`

:   Use [`biblatex`] for citations in LaTeX output.  This option is not for use
    with the `pandoc-citeproc` filter or with PDF output. It is intended for
    use in producing a LaTeX file that can be processed with [`bibtex`] or [`biber`].

Math rendering in HTML
----------------------

The default is to render TeX math as far as possible using Unicode characters.
Formulas are put inside a `span` with `class="math"`, so that they may be styled
differently from the surrounding text if needed. However, this gives acceptable
results only for basic math, usually you will want to use `--mathjax` or another
of the following options.

`--mathjax`[`=`*URL*]

:   Use [MathJax] to display embedded TeX math in HTML output.
    TeX math will be put between `\(...\)` (for inline math)
    or `\[...\]` (for display math) and wrapped in `<span>` tags
    with class `math`. Then the MathJax JavaScript will render it.
    The *URL* should point to the `MathJax.js` load script.
    If a *URL* is not provided, a link to the Cloudflare CDN will
    be inserted.

`--mathml`

:   Convert TeX math to [MathML] (in `epub3`, `docbook4`, `docbook5`, `jats`,
    `html4` and `html5`).  This is the default in `odt` output. Note that
    currently only Firefox and Safari (and select e-book readers) natively
    support MathML.

`--webtex`[`=`*URL*]

:   Convert TeX formulas to `<img>` tags that link to an external script
    that converts formulas to images. The formula will be URL-encoded
    and concatenated with the URL provided. For SVG images you can for
    example use `--webtex https://latex.codecogs.com/svg.latex?`.
    If no URL is specified, the CodeCogs URL generating PNGs
    will be used (`https://latex.codecogs.com/png.latex?`).
    Note:  the `--webtex` option will affect Markdown output
    as well as HTML, which is useful if you're targeting a
    version of Markdown without native math support.

`--katex`[`=`*URL*]

:   Use [KaTeX] to display embedded TeX math in HTML output.
    The *URL* is the base URL for the KaTeX library. If a *URL* is
    not provided, a link to the KaTeX CDN will be inserted.

`--katex-stylesheet=`*URL*

:   The *URL* should point to the `katex.css` stylesheet. If this option is
    not specified, a link to the KaTeX CDN will be inserted. Note that this
    option does not imply `--katex`.

`-m` [*URL*], `--latexmathml`[`=`*URL*]

:   *Deprecated.*
    Use the [LaTeXMathML] script to display embedded TeX math in HTML output.
    TeX math will be displayed between `$` or `$$` characters and put in
    `<span>` tags with class `LaTeX`. The LaTeXMathML JavaScript will then
    change it to MathML. Note that currently only Firefox and Safari
    (and select e-book readers) natively support MathML.
    To insert a link the `LaTeXMathML.js` script, provide a *URL*.

`--jsmath`[`=`*URL*]

:   *Deprecated.*
    Use [jsMath] (the predecessor of MathJax) to display embedded TeX
    math in HTML output. TeX math will be put inside `<span>` tags
    (for inline math) or `<div>` tags (for display math) with class
    `math` and rendered by the jsMath script. The *URL* should point to
    the script (e.g. `jsMath/easy/load.js`); if provided, it will be linked
    to in the header of standalone HTML documents. If a *URL* is not provided,
    no link to the jsMath load script will be inserted; it is then
    up to the author to provide such a link in the HTML template.

`--gladtex`

:   *Deprecated.*
    Enclose TeX math in `<eq>` tags in HTML output.  The resulting HTML
    can then be processed by [gladTeX] to produce images of the typeset
    formulas and an HTML file with links to these images.
    So, the procedure is:

        pandoc -s --gladtex input.md -o myfile.htex
        gladtex -d myfile-images myfile.htex
        # produces myfile.html and images in myfile-images

`--mimetex`[`=`*URL*]

:   *Deprecated.*
    Render TeX math using the [mimeTeX] CGI script, which generates an
    image for each TeX formula. This should work in all browsers. If
    *URL* is not specified, it is assumed that the script is at
    `/cgi-bin/mimetex.cgi`.

[MathML]: http://www.w3.org/Math/
[LaTeXMathML]: http://math.etsu.edu/LaTeXMathML/
[jsMath]: http://www.math.union.edu/~dpvc/jsmath/
[MathJax]: https://www.mathjax.org
[gladTeX]: http://ans.hsh.no/home/mgg/gladtex/
[mimeTeX]: http://www.forkosh.com/mimetex.html
[KaTeX]: https://github.com/Khan/KaTeX

Options for wrapper scripts
---------------------------

`--dump-args`

:   Print information about command-line arguments to *stdout*, then exit.
    This option is intended primarily for use in wrapper scripts.
    The first line of output contains the name of the output file specified
    with the `-o` option, or `-` (for *stdout*) if no output file was
    specified.  The remaining lines contain the command-line arguments,
    one per line, in the order they appear.  These do not include regular
    pandoc options and their arguments, but do include any options appearing
    after a `--` separator at the end of the line.

`--ignore-args`

:   Ignore command-line arguments (for use in wrapper scripts).
    Regular pandoc options are not ignored.  Thus, for example,

        pandoc --ignore-args -o foo.html -s foo.txt -- -e latin1

    is equivalent to

        pandoc -o foo.html -s

Templates
=========

When the `-s/--standalone` option is used, pandoc uses a template to
add header and footer material that is needed for a self-standing
document.  To see the default template that is used, just type

    pandoc -D *FORMAT*

where *FORMAT* is the name of the output format. A custom template
can be specified using the `--template` option.  You can also override
the system default templates for a given output format *FORMAT*
by putting a file `templates/default.*FORMAT*` in the user data
directory (see `--data-dir`, above). *Exceptions:*

- For `odt` output, customize the `default.opendocument`
  template.
- For `pdf` output, customize the `default.latex` template
  (or the `default.context` template, if you use `-t context`,
  or the `default.ms` template, if you use `-t ms`, or the
  `default.html5` template, if you use `-t html5`).
- `docx` has no template (however, you can use
  `--reference-doc` to customize the output).

Templates contain *variables*, which allow for the inclusion of
arbitrary information at any point in the file. Variables may be set
within the document using [YAML metadata blocks][Extension:
`yaml_metadata_block`].  They may also be set at the
command line using the `-V/--variable` option: variables set in this
way override metadata fields with the same name.

Variables set by pandoc
-----------------------

Some variables are set automatically by pandoc.  These vary somewhat
depending on the output format, but include metadata fields as well
as the following:

`sourcefile`, `outputfile`
:   source and destination filenames, as given on the command line.
    `sourcefile` can also be a list if input comes from multiple files, or empty
    if input is from stdin. You can use the following snippet in your template
    to distinguish them:

        $if(sourcefile)$
        $for(sourcefile)$
        $sourcefile$
        $endfor$
        $else$
        (stdin)
        $endif$

    Similarly, `outputfile` can be `-` if output goes to the terminal.

`title`, `author`, `date`
:   allow identification of basic aspects of the document.  Included
    in PDF metadata through LaTeX and ConTeXt.  These can be set
    through a [pandoc title block][Extension: `pandoc_title_block`],
    which allows for multiple authors, or through a YAML metadata block:

        ---
        author:
        - Aristotle
        - Peter Abelard
        ...

`subtitle`
:   document subtitle, included in HTML, EPUB, LaTeX, ConTeXt, and Word docx;
    renders in LaTeX only when using a document class that supports
    `\subtitle`, such as `beamer` or the [KOMA-Script] series (`scrartcl`,
    `scrreprt`, `scrbook`).[^subtitle]

`institute`
:   author affiliations (in LaTeX and Beamer only).  Can be a
    list, when there are multiple authors.

`abstract`
:   document summary, included in LaTeX, ConTeXt, AsciiDoc, and Word docx

`keywords`
:   list of keywords to be included in HTML, PDF, and AsciiDoc metadata;
    may be repeated as for `author`, above

`header-includes`
:   contents specified by `-H/--include-in-header` (may have multiple
    values)

`toc`
:   non-null value if `--toc/--table-of-contents` was specified

`toc-title`
:   title of table of contents (works only with EPUB,
    opendocument, odt, docx)

`include-before`
:   contents specified by `-B/--include-before-body` (may have
    multiple values)

`include-after`
:   contents specified by `-A/--include-after-body` (may have
    multiple values)

`body`
:   body of document

`meta-json`
:   JSON representation of all of the document's metadata. Field
    values are transformed to the selected output format.

[^subtitle]: To make `subtitle` work with other LaTeX
    document classes, you can add the following to `header-includes`:

        \providecommand{\subtitle}[1]{%
          \usepackage{titling}
          \posttitle{%
            \par\large#1\end{center}}
        }

Language variables
------------------

`lang`
:   identifies the main language of the document,
    using a code according to [BCP 47] (e.g. `en` or `en-GB`).
    For some output formats, pandoc will convert it to an appropriate
    format stored in the additional variables `babel-lang`,
    `polyglossia-lang` (LaTeX) and `context-lang` (ConTeXt).

    Native pandoc `span`s and `div`s with the lang attribute
    (value in BCP 47) can be used to switch the language in
    that range.

`otherlangs`
:   a list of other languages used in the document
    in the YAML metadata, according to [BCP 47]. For example:
    `otherlangs: [en-GB, fr]`.
    This is automatically generated from the `lang` attributes
    in all `span`s and `div`s but can be overridden.
    Currently only used by LaTeX through the generated
    `babel-otherlangs` and `polyglossia-otherlangs` variables.
    The LaTeX writer outputs polyglossia commands in the text but
    the `babel-newcommands` variable contains mappings for them
    to the corresponding babel.

`dir`
:   the base direction of the document, either `rtl` (right-to-left)
    or `ltr` (left-to-right).

    For bidirectional documents, native pandoc `span`s and `div`s
    with the `dir` attribute (value `rtl` or `ltr`) can be used to
    override the base direction in some output formats.
    This may not always be necessary if the final renderer
    (e.g. the browser, when generating HTML) supports the
    [Unicode Bidirectional Algorithm].

    When using LaTeX for bidirectional documents, only the `xelatex` engine
    is fully supported (use `--pdf-engine=xelatex`).

[BCP 47]: https://tools.ietf.org/html/bcp47
[Unicode Bidirectional Algorithm]: http://www.w3.org/International/articles/inline-bidi-markup/uba-basics

Variables for slides
--------------------

Variables are available for [producing slide shows with pandoc],
including all [reveal.js configuration options].

`titlegraphic`
:   title graphic for Beamer documents

`logo`
:   logo for Beamer documents

`slidy-url`
:   base URL for Slidy documents (defaults to
    `https://www.w3.org/Talks/Tools/Slidy2`)

`slideous-url`
:   base URL for Slideous documents (defaults to `slideous`)

`s5-url`
:   base URL for S5 documents (defaults to `s5/default`)

`revealjs-url`
:   base URL for reveal.js documents (defaults to `reveal.js`)

`theme`, `colortheme`, `fonttheme`, `innertheme`, `outertheme`
:   themes for LaTeX [`beamer`] documents

`themeoptions`
:   options for LaTeX beamer themes (a list).

`navigation`
:   controls navigation symbols in `beamer` documents
    (default is `empty` for no navigation symbols; other valid values
    are `frame`, `vertical`, and `horizontal`).

`section-titles`
:   enables on "title pages" for new sections in `beamer`
    documents (default = true).

`beamerarticle`
:   when true, the `beamerarticle` package is loaded (for
    producing an article from beamer slides).

`aspectratio`
:   aspect ratio of slides (for beamer only, `1610` for 16:10, `169` for 16:9,
    `149` for 14:9, `141` for 1.41:1, `54` for 5:4, `43` for 4:3 which is the
    default, and `32` for 3:2).

[reveal.js configuration options]: https://github.com/hakimel/reveal.js#configuration

Variables for LaTeX
-------------------

LaTeX variables are used when [creating a PDF].

`papersize`
:   paper size, e.g. `letter`, `a4`

`fontsize`
:   font size for body text (e.g. `10pt`, `12pt`)

`documentclass`
:   document class, e.g. [`article`], [`report`], [`book`], [`memoir`]

`classoption`
:   option for document class, e.g. `oneside`; may be repeated
    for multiple options

`geometry`
:   option for [`geometry`] package, e.g. `margin=1in`;
    may be repeated for multiple options

`margin-left`, `margin-right`, `margin-top`, `margin-bottom`
:   sets margins, if `geometry` is not used (otherwise `geometry`
    overrides these)

`linestretch`
:   adjusts line spacing using the [`setspace`]
    package, e.g. `1.25`, `1.5`

`fontfamily`
:   font package for use with `pdflatex`:
    [TeX Live] includes many options, documented in the [LaTeX Font Catalogue].
    The default is [Latin Modern][`lm`].

`fontfamilyoptions`
:   options for package used as `fontfamily`: e.g. `osf,sc` with
    `fontfamily` set to [`mathpazo`] provides Palatino with old-style
    figures and true small caps; may be repeated for multiple options

`mainfont`, `sansfont`, `monofont`, `mathfont`, `CJKmainfont`
:   font families for use with `xelatex` or
    `lualatex`: take the name of any system font, using the
    [`fontspec`] package.  Note that if `CJKmainfont` is used,
    the [`xecjk`] package must be available.

`mainfontoptions`, `sansfontoptions`, `monofontoptions`, `mathfontoptions`, `CJKoptions`
:   options to use with `mainfont`, `sansfont`, `monofont`, `mathfont`,
    `CJKmainfont` in `xelatex` and `lualatex`.  Allow for any choices
    available through [`fontspec`], such as the OpenType features
    `Numbers=OldStyle,Numbers=Proportional`. May be repeated for multiple options.

`fontenc`
:   allows font encoding to be specified through `fontenc` package (with `pdflatex`);
    default is `T1` (see guide to [LaTeX font encodings])

`microtypeoptions`
:    options to pass to the microtype package

`colorlinks`
:   add color to link text; automatically enabled if any of `linkcolor`, `citecolor`,
    `urlcolor`, or `toccolor` are set

`linkcolor`, `citecolor`, `urlcolor`, `toccolor`
:   color for internal links, citation links, external links, and links in table of contents:
    uses options allowed by [`xcolor`], including the `dvipsnames`, `svgnames`, and `x11names` lists

`links-as-notes`
:   causes links to be printed as footnotes

`indent`
:   uses document class settings for indentation (the default LaTeX template
    otherwise removes indentation and adds space between paragraphs)

`subparagraph`
:   disables default behavior of LaTeX template that redefines (sub)paragraphs
    as sections, changing the appearance of nested headings in some classes

`thanks`
:   specifies contents of acknowledgments footnote after document title.

`toc`
:   include table of contents (can also be set using `--toc/--table-of-contents`)

`toc-depth`
:   level of section to include in table of contents

`secnumdepth`
:   numbering depth for sections, if sections are numbered

`lof`, `lot`
:   include list of figures, list of tables

`bibliography`
:   bibliography to use for resolving references

`biblio-style`
:   bibliography style, when used with `--natbib` and `--biblatex`.

`biblio-title`
:   bibliography title, when used with `--natbib` and `--biblatex`.

`biblatexoptions`
:   list of options for biblatex.

`natbiboptions`
:   list of options for natbib.

`pagestyle`
:   An option for LaTeX's `\pagestyle{}`. The default article class
    supports 'plain' (default), 'empty', and 'headings'; headings puts
    section titles in the header.

[`article`]: https://ctan.org/pkg/article
[`report`]: https://ctan.org/pkg/report
[`book`]: https://ctan.org/pkg/book
[KOMA-Script]: https://ctan.org/pkg/koma-script
[`memoir`]: https://ctan.org/pkg/memoir
[`xcolor`]: https://ctan.org/pkg/xcolor
[LaTeX Font Catalogue]: http://www.tug.dk/FontCatalogue/
[`mathpazo`]: https://ctan.org/pkg/mathpazo
[LaTeX font encodings]: https://ctan.org/pkg/encguide

Variables for ConTeXt
---------------------

`papersize`
:   paper size, e.g. `letter`, `A4`, `landscape` (see [ConTeXt Paper Setup]);
    may be repeated for multiple options

`layout`
:   options for page margins and text arrangement (see [ConTeXt Layout]);
    may be repeated for multiple options

`margin-left`, `margin-right`, `margin-top`, `margin-bottom`
:   sets margins, if `layout` is not used (otherwise `layout`
    overrides these)

`fontsize`
:   font size for body text (e.g. `10pt`, `12pt`)

`mainfont`, `sansfont`, `monofont`, `mathfont`
:   font families: take the name of any system font (see [ConTeXt Font Switching])

`linkcolor`, `contrastcolor`
:   color for links outside and inside a page, e.g. `red`, `blue` (see [ConTeXt Color])

`linkstyle`
:   typeface style for links, e.g. `normal`, `bold`, `slanted`, `boldslanted`, `type`, `cap`, `small`

`indenting`
:   controls indentation of paragraphs, e.g. `yes,small,next` (see [ConTeXt Indentation]);
    may be repeated for multiple options

`whitespace`
:   spacing between paragraphs, e.g. `none`, `small` (using [`setupwhitespace`])

`interlinespace`
:   adjusts line spacing, e.g. `4ex` (using [`setupinterlinespace`]);
    may be repeated for multiple options

`headertext`, `footertext`
:   text to be placed in running header or footer (see [ConTeXt Headers and Footers]);
    may be repeated up to four times for different placement

`pagenumbering`
:   page number style and location (using [`setuppagenumbering`]);
    may be repeated for multiple options

`toc`
:   include table of contents (can also be set using `--toc/--table-of-contents`)

`lof`, `lot`
:   include list of figures, list of tables

[ConTeXt Paper Setup]: http://wiki.contextgarden.net/PaperSetup
[ConTeXt Layout]: http://wiki.contextgarden.net/Layout
[ConTeXt Font Switching]: http://wiki.contextgarden.net/Font_Switching
[ConTeXt Color]: http://wiki.contextgarden.net/Color
[ConTeXt Headers and Footers]: http://wiki.contextgarden.net/Headers_and_Footers
[ConTeXt Indentation]: http://wiki.contextgarden.net/Indentation
[`setupwhitespace`]: http://wiki.contextgarden.net/Command/setupwhitespace
[`setupinterlinespace`]: http://wiki.contextgarden.net/Command/setupinterlinespace
[`setuppagenumbering`]: http://wiki.contextgarden.net/Command/setuppagenumbering

Variables for man pages
-----------------------

`section`
:   section number in man pages

`header`
:   header in man pages

`footer`
:   footer in man pages

`adjusting`
:   adjusts text to left (`l`), right (`r`), center (`c`),
    or both (`b`) margins

`hyphenate`
:   if `true` (the default), hyphenation will be used

Variables for ms
----------------

`pointsize`
:    point size (e.g. `10p`)

`lineheight`
:    line height (e.g. `12p`)

`fontfamily`
:    font family (e.g. `T` or `P`)

`indent`
:    paragraph indent (e.g. `2m`)

Using variables in templates
----------------------------

Variable names are sequences of alphanumerics, `-`, and `_`,
starting with a letter.  A variable name surrounded by `$` signs
will be replaced by its value.  For example, the string `$title$` in

    <title>$title$</title>

will be replaced by the document title.

To write a literal `$` in a template, use `$$`.

Templates may contain conditionals.  The syntax is as follows:

    $if(variable)$
    X
    $else$
    Y
    $endif$

This will include `X` in the template if `variable` has a non-null
value; otherwise it will include `Y`. `X` and `Y` are placeholders for
any valid template text, and may include interpolated variables or other
conditionals. The `$else$` section may be omitted.

When variables can have multiple values (for example, `author` in
a multi-author document), you can use the `$for$` keyword:

    $for(author)$
    <meta name="author" content="$author$" />
    $endfor$

You can optionally specify a separator to be used between
consecutive items:

    $for(author)$$author$$sep$, $endfor$

A dot can be used to select a field of a variable that takes
an object as its value.  So, for example:

    $author.name$ ($author.affiliation$)

If you use custom templates, you may need to revise them as pandoc
changes.  We recommend tracking the changes in the default templates,
and modifying your custom templates accordingly. An easy way to do this
is to fork the [pandoc-templates] repository and merge in changes after each
pandoc release.

Templates may contain comments:  anything on a line after `$--`
will be treated as a comment and ignored.

[pandoc-templates]: https://github.com/jgm/pandoc-templates

Extensions
==========

The behavior of some of the readers and writers can be adjusted by
enabling or disabling various extensions.

An extension can be enabled by adding `+EXTENSION`
to the format name and disabled by adding `-EXTENSION`. For example,
`--from markdown_strict+footnotes` is strict Markdown with footnotes
enabled, while `--from markdown-footnotes-pipe_tables` is pandoc's
Markdown without footnotes or pipe tables.

The markdown reader and writer make by far the most use of extensions.
Extensions only used by them are therefore covered in the
section [Pandoc's Markdown] below (See [Markdown variants] for
`commonmark` and `gfm`.) In the following, extensions that also work
for other formats are covered.

Typography
----------

#### Extension: `smart` ####

Interpret straight quotes as curly quotes, `---` as em-dashes,
`--` as en-dashes, and `...` as ellipses. Nonbreaking spaces are
inserted after certain abbreviations, such as "Mr." 

This extension can be enabled/disabled for the following formats:

input formats
:  `markdown`, `commonmark`, `latex`, `mediawiki`, `org`, `rst`, `twiki`

output formats
:  `markdown`, `latex`, `context`, `rst`

enabled by default in
:  `markdown`, `latex`, `context` (both input and output)

Note: If you are *writing* Markdown, then the `smart` extension
has the reverse effect: what would have been curly quotes comes
out straight.

In LaTeX, `smart` means to use the standard TeX ligatures
for quotation marks (` `` ` and ` '' ` for double quotes,
`` ` `` and `` ' `` for single quotes) and dashes (`--` for
en-dash and `---` for em-dash).  If `smart` is disabled,
then in reading LaTeX pandoc will parse these characters
literally.  In writing LaTeX, enabling `smart` tells pandoc
to use the ligatures when possible; if `smart` is disabled
pandoc will use unicode quotation mark and dash characters.

Headers and sections
--------------------

#### Extension: `auto_identifiers` ####

A header without an explicitly specified identifier will be
automatically assigned a unique identifier based on the header text.

This extension can be enabled/disabled for the following formats:

input formats
:  `markdown`, `latex`, `rst`, `mediawiki`, `textile`

output formats
:  `markdown`, `muse`

enabled by default in
:  `markdown`, `muse`

The algorithm used to derive the identifier from the header text is:

  - Remove all formatting, links, etc.
  - Remove all footnotes.
  - Remove all punctuation, except underscores, hyphens, and periods.
  - Replace all spaces and newlines with hyphens.
  - Convert all alphabetic characters to lowercase.
  - Remove everything up to the first letter (identifiers may
    not begin with a number or punctuation mark).
  - If nothing is left after this, use the identifier `section`.

Thus, for example,

  Header                            Identifier
  -------------------------------   ----------------------------
  `Header identifiers in HTML`      `header-identifiers-in-html`
  `*Dogs*?--in *my* house?`         `dogs--in-my-house`
  `[HTML], [S5], or [RTF]?`         `html-s5-or-rtf`
  `3. Applications`                 `applications`
  `33`                              `section`

These rules should, in most cases, allow one to determine the identifier
from the header text. The exception is when several headers have the
same text; in this case, the first will get an identifier as described
above; the second will get the same identifier with `-1` appended; the
third with `-2`; and so on.

These identifiers are used to provide link targets in the table of
contents generated by the `--toc|--table-of-contents` option. They
also make it easy to provide links from one section of a document to
another. A link to this section, for example, might look like this:

    See the section on
    [header identifiers](#header-identifiers-in-html-latex-and-context).

Note, however, that this method of providing links to sections works
only in HTML, LaTeX, and ConTeXt formats.

If the `--section-divs` option is specified, then each section will
be wrapped in a `section` (or a `div`, if `html4` was specified),
and the identifier will be attached to the enclosing `<section>`
(or `<div>`) tag rather than the header itself. This allows entire
sections to be manipulated using JavaScript or treated differently in
CSS.

#### Extension: `ascii_identifiers` ####

Causes the identifiers produced by `auto_identifiers` to be pure ASCII.
Accents are stripped off of accented Latin letters, and non-Latin
letters are omitted.

Math Input
----------

The extensions [`tex_math_dollars`](#extension-tex_math_dollars),
[`tex_math_single_backslash`](#extension-tex_math_single_backslash), and
[`tex_math_double_backslash`](#extension-tex_math_double_backslash)
are described in the section about Pandoc's Markdown.

However, they can also be used with HTML input. This is handy for
reading web pages formatted using MathJax, for example.

Raw HTML/TeX
------------

The following extensions (especially how they affect Markdown
input/output) are also described in more detail in their respective
sections of [Pandoc's Markdown].

#### [Extension: `raw_html`] {#raw_html}

When converting from HTML, parse elements to raw HTML which are not
representable in pandoc's AST.
By default, this is disabled for HTML input.

#### [Extension: `raw_tex`] {#raw_tex}

Allows raw LaTeX, TeX, and ConTeXt to be included in a document.

This extension can be enabled/disabled for the following formats
(in addition to `markdown`):

input formats
:  `latex`, `org`, `textile`

output formats
:  `textile`

#### [Extension: `native_divs`] {#native_divs}

This extension is enabled by default for HTML input. This means that
`div`s are parsed to pandoc native elements. (Alternatively, you
can parse them to raw HTML using `-f html-native_divs+raw_html`.)

When converting HTML to Markdown, for example, you may want to drop all
`div`s and `span`s:

    pandoc -f html-native_divs-native_spans -t markdown

#### [Extension: `native_spans`] {#native_spans}

Analogous to `native_divs` above.


Literate Haskell support
------------------------

#### Extension: `literate_haskell` ####

Treat the document as literate Haskell source.

This extension can be enabled/disabled for the following formats:

input formats
:  `markdown`, `rst`, `latex`

output formats
:  `markdown`, `rst`, `latex`, `html`

If you append `+lhs` (or `+literate_haskell`) to one of the formats
above, pandoc will treat the document as literate Haskell source.
This means that

  - In Markdown input, "bird track" sections will be parsed as Haskell
    code rather than block quotations.  Text between `\begin{code}`
    and `\end{code}` will also be treated as Haskell code.  For
    ATX-style headers the character '=' will be used instead of '#'.

  - In Markdown output, code blocks with classes `haskell` and `literate`
    will be rendered using bird tracks, and block quotations will be
    indented one space, so they will not be treated as Haskell code.
    In addition, headers will be rendered setext-style (with underlines)
    rather than ATX-style (with '#' characters). (This is because ghc
    treats '#' characters in column 1 as introducing line numbers.)

  - In restructured text input, "bird track" sections will be parsed
    as Haskell code.

  - In restructured text output, code blocks with class `haskell` will
    be rendered using bird tracks.

  - In LaTeX input, text in `code` environments will be parsed as
    Haskell code.

  - In LaTeX output, code blocks with class `haskell` will be rendered
    inside `code` environments.

  - In HTML output, code blocks with class `haskell` will be rendered
    with class `literatehaskell` and bird tracks.

Examples:

    pandoc -f markdown+lhs -t html

reads literate Haskell source formatted with Markdown conventions and writes
ordinary HTML (without bird tracks).

    pandoc -f markdown+lhs -t html+lhs

writes HTML with the Haskell code in bird tracks, so it can be copied
and pasted as literate Haskell source.

Note that GHC expects the bird tracks in the first column, so indentend literate
code blocks (e.g. inside an itemized environment) will not be picked up by the
Haskell compiler.

Other extensions
----------------

#### Extension: `empty_paragraphs` ####

Allows empty paragraphs.  By default empty paragraphs are
omitted.

This extension can be enabled/disabled for the following formats:

input formats
:  `docx`, `html`

output formats
:  `markdown`, `docx`, `odt`, `opendocument`, `html`

#### Extension: `amuse` ####

In the `muse` input format, this enables Text::Amuse
extensions to Emacs Muse markup.

#### Extension: `citations` {#org-citations}

Some aspects of [Pandoc's Markdown citation syntax](#citations) are also accepted
in `org` input.


Pandoc's Markdown
=================

Pandoc understands an extended and slightly revised version of
John Gruber's [Markdown] syntax.  This document explains the syntax,
noting differences from standard Markdown. Except where noted, these
differences can be suppressed by using the `markdown_strict` format instead
of `markdown`. Extensions can be enabled or disabled to specify the
behavior more granularly. They are described in the following. See also
[Extensions] above, for extensions that work also on other formats.

Philosophy
----------

Markdown is designed to be easy to write, and, even more importantly,
easy to read:

> A Markdown-formatted document should be publishable as-is, as plain
> text, without looking like it's been marked up with tags or formatting
> instructions.
> -- [John Gruber](http://daringfireball.net/projects/markdown/syntax#philosophy)

This principle has guided pandoc's decisions in finding syntax for
tables, footnotes, and other extensions.

There is, however, one respect in which pandoc's aims are different
from the original aims of Markdown.  Whereas Markdown was originally
designed with HTML generation in mind, pandoc is designed for multiple
output formats.  Thus, while pandoc allows the embedding of raw HTML,
it discourages it, and provides other, non-HTMLish ways of representing
important document elements like definition lists, tables, mathematics, and
footnotes.

Paragraphs
----------

A paragraph is one or more lines of text followed by one or more blank lines.
Newlines are treated as spaces, so you can reflow your paragraphs as you like.
If you need a hard line break, put two or more spaces at the end of a line.

#### Extension: `escaped_line_breaks` ####

A backslash followed by a newline is also a hard line break.
Note:  in multiline and grid table cells, this is the only way
to create a hard line break, since trailing spaces in the cells
are ignored.

Headers
-------

There are two kinds of headers: Setext and ATX.

### Setext-style headers ###

A setext-style header is a line of text "underlined" with a row of `=` signs
(for a level one header) or `-` signs (for a level two header):

    A level-one header
    ==================

    A level-two header
    ------------------

The header text can contain inline formatting, such as emphasis (see
[Inline formatting], below).


### ATX-style headers ###

An ATX-style header consists of one to six `#` signs and a line of
text, optionally followed by any number of `#` signs.  The number of
`#` signs at the beginning of the line is the header level:

    ## A level-two header

    ### A level-three header ###

As with setext-style headers, the header text can contain formatting:

    # A level-one header with a [link](/url) and *emphasis*

#### Extension: `blank_before_header` ####

Standard Markdown syntax does not require a blank line before a header.
Pandoc does require this (except, of course, at the beginning of the
document). The reason for the requirement is that it is all too easy for a
`#` to end up at the beginning of a line by accident (perhaps through line
wrapping). Consider, for example:

    I like several of their flavors of ice cream:
    #22, for example, and #5.

#### Extension: `space_in_atx_header` ####

Many Markdown implementations do not require a space between the
opening `#`s of an ATX header and the header text, so that
`#5 bolt` and `#hashtag` count as headers.  With this extension,
pandoc does require the space.

### Header identifiers ###

See also the [`auto_identifiers` extension](#extension-auto_identifiers) above.

#### Extension: `header_attributes` ####

Headers can be assigned attributes using this syntax at the end
of the line containing the header text:

    {#identifier .class .class key=value key=value}

Thus, for example, the following headers will all be assigned the identifier
`foo`:

    # My header {#foo}

    ## My header ##    {#foo}

    My other header   {#foo}
    ---------------

(This syntax is compatible with [PHP Markdown Extra].)

Note that although this syntax allows assignment of classes and key/value
attributes, writers generally don't use all of this information.  Identifiers,
classes, and key/value attributes are used in HTML and HTML-based formats such
as EPUB and slidy.  Identifiers are used for labels and link anchors in the
LaTeX, ConTeXt, Textile, and AsciiDoc writers.

Headers with the class `unnumbered` will not be numbered, even if
`--number-sections` is specified.  A single hyphen (`-`) in an attribute
context is equivalent to `.unnumbered`, and preferable in non-English
documents.  So,

    # My header {-}

is just the same as

    # My header {.unnumbered}

#### Extension: `implicit_header_references` ####

Pandoc behaves as if reference links have been defined for each header.
So, to link to a header

    # Header identifiers in HTML

you can simply write

    [Header identifiers in HTML]

or

    [Header identifiers in HTML][]

or

    [the section on header identifiers][header identifiers in
    HTML]

instead of giving the identifier explicitly:

    [Header identifiers in HTML](#header-identifiers-in-html)

If there are multiple headers with identical text, the corresponding
reference will link to the first one only, and you will need to use explicit
links to link to the others, as described above.

Like regular reference links, these references are case-insensitive.

Explicit link reference definitions always take priority over
implicit header references.  So, in the following example, the
link will point to `bar`, not to `#foo`:

    # Foo

    [foo]: bar

    See [foo]

Block quotations
----------------

Markdown uses email conventions for quoting blocks of text.
A block quotation is one or more paragraphs or other block elements
(such as lists or headers), with each line preceded by a `>` character
and an optional space. (The `>` need not start at the left margin, but
it should not be indented more than three spaces.)

    > This is a block quote. This
    > paragraph has two lines.
    >
    > 1. This is a list inside a block quote.
    > 2. Second item.

A "lazy" form, which requires the `>` character only on the first
line of each block, is also allowed:

    > This is a block quote. This
    paragraph has two lines.

    > 1. This is a list inside a block quote.
    2. Second item.

Among the block elements that can be contained in a block quote are
other block quotes. That is, block quotes can be nested:

    > This is a block quote.
    >
    > > A block quote within a block quote.

If the `>` character is followed by an optional space, that space
will be considered part of the block quote marker and not part of
the indentation of the contents.  Thus, to put an indented code
block in a block quote, you need five spaces after the `>`:

    >     code

#### Extension: `blank_before_blockquote` ####

Standard Markdown syntax does not require a blank line before a block
quote.  Pandoc does require this (except, of course, at the beginning of the
document). The reason for the requirement is that it is all too easy for a
`>` to end up at the beginning of a line by accident (perhaps through line
wrapping). So, unless the `markdown_strict` format is used, the following does
not produce a nested block quote in pandoc:

    > This is a block quote.
    >> Nested.


Verbatim (code) blocks
----------------------

### Indented code blocks ###

A block of text indented four spaces (or one tab) is treated as verbatim
text: that is, special characters do not trigger special formatting,
and all spaces and line breaks are preserved.  For example,

        if (a > 3) {
          moveShip(5 * gravity, DOWN);
        }

The initial (four space or one tab) indentation is not considered part
of the verbatim text, and is removed in the output.

Note: blank lines in the verbatim text need not begin with four spaces.


### Fenced code blocks ###

#### Extension: `fenced_code_blocks` ####

In addition to standard indented code blocks, pandoc supports
*fenced* code blocks.  These begin with a row of three or more
tildes (`~`) and end with a row of tildes that must be at least as long as
the starting row. Everything between these lines is treated as code. No
indentation is necessary:

    ~~~~~~~
    if (a > 3) {
      moveShip(5 * gravity, DOWN);
    }
    ~~~~~~~

Like regular code blocks, fenced code blocks must be separated
from surrounding text by blank lines.

If the code itself contains a row of tildes or backticks, just use a longer
row of tildes or backticks at the start and end:

    ~~~~~~~~~~~~~~~~
    ~~~~~~~~~~
    code including tildes
    ~~~~~~~~~~
    ~~~~~~~~~~~~~~~~

#### Extension: `backtick_code_blocks` ####

Same as `fenced_code_blocks`, but uses backticks (`` ` ``) instead of tildes
(`~`).

#### Extension: `fenced_code_attributes` ####

Optionally, you may attach attributes to fenced or backtick code block using
this syntax:

    ~~~~ {#mycode .haskell .numberLines startFrom="100"}
    qsort []     = []
    qsort (x:xs) = qsort (filter (< x) xs) ++ [x] ++
                   qsort (filter (>= x) xs)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here `mycode` is an identifier, `haskell` and `numberLines` are classes, and
`startFrom` is an attribute with value `100`. Some output formats can use this
information to do syntax highlighting. Currently, the only output formats
that uses this information are HTML, LaTeX, Docx, and Ms. If highlighting
is supported for your output format and language, then the code block above
will appear highlighted, with numbered lines. (To see which languages are
supported, type `pandoc --list-highlight-languages`.) Otherwise, the code
block above will appear as follows:

    <pre id="mycode" class="haskell numberLines" startFrom="100">
      <code>
      ...
      </code>
    </pre>

The `numberLines` (or `number-lines`) class will cause the lines
of the code block to be numbered, starting with `1` or the value
of the `startFrom` attribute.  The `lineAnchors` (or
`line-anchors`) class will cause the lines to be clickable
anchors in HTML output.

A shortcut form can also be used for specifying the language of
the code block:

    ```haskell
    qsort [] = []
    ```

This is equivalent to:

    ``` {.haskell}
    qsort [] = []
    ```

If the `fenced_code_attributes` extension is disabled, but
input contains class attribute(s) for the code block, the first
class attribute will be printed after the opening fence as a bare
word.

To prevent all highlighting, use the `--no-highlight` flag.
To set the highlighting style, use `--highlight-style`.
For more information on highlighting, see [Syntax highlighting],
below.

Line blocks
-----------

#### Extension: `line_blocks` ####

A line block is a sequence of lines beginning with a vertical bar (`|`)
followed by a space.  The division into lines will be preserved in
the output, as will any leading spaces; otherwise, the lines will
be formatted as Markdown.  This is useful for verse and addresses:

    | The limerick packs laughs anatomical
    | In space that is quite economical.
    |    But the good ones I've seen
    |    So seldom are clean
    | And the clean ones so seldom are comical

    | 200 Main St.
    | Berkeley, CA 94718

The lines can be hard-wrapped if needed, but the continuation
line must begin with a space.

    | The Right Honorable Most Venerable and Righteous Samuel L.
      Constable, Jr.
    | 200 Main St.
    | Berkeley, CA 94718

This syntax is borrowed from [reStructuredText].

Lists
-----

### Bullet lists ###

A bullet list is a list of bulleted list items.  A bulleted list
item begins with a bullet (`*`, `+`, or `-`).  Here is a simple
example:

    * one
    * two
    * three

This will produce a "compact" list. If you want a "loose" list, in which
each item is formatted as a paragraph, put spaces between the items:

    * one

    * two

    * three

The bullets need not be flush with the left margin; they may be
indented one, two, or three spaces. The bullet must be followed
by whitespace.

List items look best if subsequent lines are flush with the first
line (after the bullet):

    * here is my first
      list item.
    * and my second.

But Markdown also allows a "lazy" format:

    * here is my first
    list item.
    * and my second.

### Block content in list items ###

A list item may contain multiple paragraphs and other block-level
content. However, subsequent paragraphs must be preceded by a blank line
and indented to line up with the first non-space content after
the list marker.

      * First paragraph.

        Continued.

      * Second paragraph. With a code block, which must be indented
        eight spaces:

            { code }

Exception: if the list marker is followed by an indented code
block, which must begin 5 spaces after the list marker, then
subsequent paragraphs must begin two columns after the last
character of the list marker:

    *     code

      continuation paragraph

List items may include other lists.  In this case the preceding blank
line is optional.  The nested list must be indented to line up with
the first non-space character after the list marker of the
containing list item.

    * fruits
      + apples
        - macintosh
        - red delicious
      + pears
      + peaches
    * vegetables
      + broccoli
      + chard

As noted above, Markdown allows you to write list items "lazily," instead of
indenting continuation lines. However, if there are multiple paragraphs or
other blocks in a list item, the first line of each must be indented.

    + A lazy, lazy, list
    item.

    + Another one; this looks
    bad but is legal.

        Second paragraph of second
    list item.

### Ordered lists ###

Ordered lists work just like bulleted lists, except that the items
begin with enumerators rather than bullets.

In standard Markdown, enumerators are decimal numbers followed
by a period and a space.  The numbers themselves are ignored, so
there is no difference between this list:

    1.  one
    2.  two
    3.  three

and this one:

    5.  one
    7.  two
    1.  three

#### Extension: `fancy_lists` ####

Unlike standard Markdown, pandoc allows ordered list items to be marked
with uppercase and lowercase letters and roman numerals, in addition to
Arabic numerals. List markers may be enclosed in parentheses or followed by a
single right-parentheses or period. They must be separated from the
text that follows by at least one space, and, if the list marker is a
capital letter with a period, by at least two spaces.[^2]

[^2]:  The point of this rule is to ensure that normal paragraphs
    starting with people's initials, like

        B. Russell was an English philosopher.

    do not get treated as list items.

    This rule will not prevent

        (C) 2007 Joe Smith

    from being interpreted as a list item.  In this case, a backslash
    escape can be used:

        (C\) 2007 Joe Smith

The `fancy_lists` extension also allows '`#`' to be used as an
ordered list marker in place of a numeral:

    #. one
    #. two

#### Extension: `startnum` ####

Pandoc also pays attention to the type of list marker used, and to the
starting number, and both of these are preserved where possible in the
output format. Thus, the following yields a list with numbers followed
by a single parenthesis, starting with 9, and a sublist with lowercase
roman numerals:

     9)  Ninth
    10)  Tenth
    11)  Eleventh
           i. subone
          ii. subtwo
         iii. subthree

Pandoc will start a new list each time a different type of list
marker is used.  So, the following will create three lists:

    (2) Two
    (5) Three
    1.  Four
    *   Five

If default list markers are desired, use `#.`:

    #.  one
    #.  two
    #.  three


### Definition lists ###

#### Extension: `definition_lists` ####

Pandoc supports definition lists, using the syntax of
[PHP Markdown Extra] with some extensions.[^3]

    Term 1

    :   Definition 1

    Term 2 with *inline markup*

    :   Definition 2

            { some code, part of Definition 2 }

        Third paragraph of definition 2.

Each term must fit on one line, which may optionally be followed by
a blank line, and must be followed by one or more definitions.
A definition begins with a colon or tilde, which may be indented one
or two spaces.

A term may have multiple definitions, and each definition may consist of one or
more block elements (paragraph, code block, list, etc.), each indented four
spaces or one tab stop.  The body of the definition (including the first line,
aside from the colon or tilde) should be indented four spaces. However,
as with other Markdown lists, you can "lazily" omit indentation except
at the beginning of a paragraph or other block element:

    Term 1

    :   Definition
    with lazy continuation.

        Second paragraph of the definition.

If you leave space before the definition (as in the example above),
the text of the definition will be treated as a paragraph.  In some
output formats, this will mean greater spacing between term/definition
pairs. For a more compact definition list, omit the space before the
definition:

    Term 1
      ~ Definition 1

    Term 2
      ~ Definition 2a
      ~ Definition 2b

Note that space between items in a definition list is required.
(A variant that loosens this requirement, but disallows "lazy"
hard wrapping, can be activated with `compact_definition_lists`: see
[Non-pandoc extensions], below.)

[^3]:  I have been influenced by the suggestions of [David Wheeler](http://www.justatheory.com/computers/markup/modest-markdown-proposal.html).

### Numbered example lists ###

#### Extension: `example_lists` ####

The special list marker `@` can be used for sequentially numbered
examples. The first list item with a `@` marker will be numbered '1',
the next '2', and so on, throughout the document. The numbered examples
need not occur in a single list; each new list using `@` will take up
where the last stopped. So, for example:

    (@)  My first example will be numbered (1).
    (@)  My second example will be numbered (2).

    Explanation of examples.

    (@)  My third example will be numbered (3).

Numbered examples can be labeled and referred to elsewhere in the
document:

    (@good)  This is a good example.

    As (@good) illustrates, ...

The label can be any string of alphanumeric characters, underscores,
or hyphens.

Note:  continuation paragraphs in example lists must always
be indented four spaces, regardless of the length of the
list marker.  That is, example lists always behave as if the
`four_space_rule` extension is set.  This is because example
labels tend to be long, and indenting content to the
first non-space character after the label would be awkward.

### Compact and loose lists ###

Pandoc behaves differently from `Markdown.pl` on some "edge
cases" involving lists.  Consider this source:

    +   First
    +   Second:
    	-   Fee
    	-   Fie
    	-   Foe

    +   Third

Pandoc transforms this into a "compact list" (with no `<p>` tags around
"First", "Second", or "Third"), while Markdown puts `<p>` tags around
"Second" and "Third" (but not "First"), because of the blank space
around "Third". Pandoc follows a simple rule: if the text is followed by
a blank line, it is treated as a paragraph. Since "Second" is followed
by a list, and not a blank line, it isn't treated as a paragraph. The
fact that the list is followed by a blank line is irrelevant. (Note:
Pandoc works this way even when the `markdown_strict` format is specified. This
behavior is consistent with the official Markdown syntax description,
even though it is different from that of `Markdown.pl`.)


### Ending a list ###

What if you want to put an indented code block after a list?

    -   item one
    -   item two

        { my code block }

Trouble! Here pandoc (like other Markdown implementations) will treat
`{ my code block }` as the second paragraph of item two, and not as
a code block.

To "cut off" the list after item two, you can insert some non-indented
content, like an HTML comment, which won't produce visible output in
any format:

    -   item one
    -   item two

    <!-- end of list -->

        { my code block }

You can use the same trick if you want two consecutive lists instead
of one big list:

    1.  one
    2.  two
    3.  three

    <!-- -->

    1.  uno
    2.  dos
    3.  tres

Horizontal rules
----------------

A line containing a row of three or more `*`, `-`, or `_` characters
(optionally separated by spaces) produces a horizontal rule:

    *  *  *  *

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


Tables
------

Four kinds of tables may be used. The first three kinds presuppose the use of
a fixed-width font, such as Courier. The fourth kind can be used with
proportionally spaced fonts, as it does not require lining up columns.

#### Extension: `table_captions` ####

A caption may optionally be provided with all 4 kinds of tables (as
illustrated in the examples below). A caption is a paragraph beginning
with the string `Table:` (or just `:`), which will be stripped off.
It may appear either before or after the table.

#### Extension: `simple_tables` ####

Simple tables look like this:

      Right     Left     Center     Default
    -------     ------ ----------   -------
         12     12        12            12
        123     123       123          123
          1     1          1             1

    Table:  Demonstration of simple table syntax.

The headers and table rows must each fit on one line.  Column
alignments are determined by the position of the header text relative
to the dashed line below it:[^4]

  - If the dashed line is flush with the header text on the right side
    but extends beyond it on the left, the column is right-aligned.
  - If the dashed line is flush with the header text on the left side
    but extends beyond it on the right, the column is left-aligned.
  - If the dashed line extends beyond the header text on both sides,
    the column is centered.
  - If the dashed line is flush with the header text on both sides,
    the default alignment is used (in most cases, this will be left).

[^4]:  This scheme is due to Michel Fortin, who proposed it on the
       [Markdown discussion list](http://six.pairlist.net/pipermail/markdown-discuss/2005-March/001097.html).

The table must end with a blank line, or a line of dashes followed by
a blank line.

The column headers may be omitted, provided a dashed line is used
to end the table. For example:

    -------     ------ ----------   -------
         12     12        12             12
        123     123       123           123
          1     1          1              1
    -------     ------ ----------   -------

When headers are omitted, column alignments are determined on the basis
of the first line of the table body. So, in the tables above, the columns
would be right, left, center, and right aligned, respectively.

#### Extension: `multiline_tables` ####

Multiline tables allow headers and table rows to span multiple lines
of text (but cells that span multiple columns or rows of the table are
not supported).  Here is an example:

    -------------------------------------------------------------
     Centered   Default           Right Left
      Header    Aligned         Aligned Aligned
    ----------- ------- --------------- -------------------------
       First    row                12.0 Example of a row that
                                        spans multiple lines.

      Second    row                 5.0 Here's another one. Note
                                        the blank line between
                                        rows.
    -------------------------------------------------------------

    Table: Here's the caption. It, too, may span
    multiple lines.

These work like simple tables, but with the following differences:

  - They must begin with a row of dashes, before the header text
    (unless the headers are omitted).
  - They must end with a row of dashes, then a blank line.
  - The rows must be separated by blank lines.

In multiline tables, the table parser pays attention to the widths of
the columns, and the writers try to reproduce these relative widths in
the output. So, if you find that one of the columns is too narrow in the
output, try widening it in the Markdown source.

Headers may be omitted in multiline tables as well as simple tables:

    ----------- ------- --------------- -------------------------
       First    row                12.0 Example of a row that
                                        spans multiple lines.

      Second    row                 5.0 Here's another one. Note
                                        the blank line between
                                        rows.
    ----------- ------- --------------- -------------------------

    : Here's a multiline table without headers.

It is possible for a multiline table to have just one row, but the row
should be followed by a blank line (and then the row of dashes that ends
the table), or the table may be interpreted as a simple table.

#### Extension: `grid_tables` ####

Grid tables look like this:

    : Sample grid table.

    +---------------+---------------+--------------------+
    | Fruit         | Price         | Advantages         |
    +===============+===============+====================+
    | Bananas       | $1.34         | - built-in wrapper |
    |               |               | - bright color     |
    +---------------+---------------+--------------------+
    | Oranges       | $2.10         | - cures scurvy     |
    |               |               | - tasty            |
    +---------------+---------------+--------------------+

The row of `=`s separates the header from the table body, and can be
omitted for a headerless table. The cells of grid tables may contain
arbitrary block elements (multiple paragraphs, code blocks, lists,
etc.). Cells that span multiple columns or rows are not
supported. Grid tables can be created easily using [Emacs table mode].

[Emacs table mode]: http://table.sourceforge.net/

Alignments can be specified as with pipe tables, by putting
colons at the boundaries of the separator line after the
header:

    +---------------+---------------+--------------------+
    | Right         | Left          | Centered           |
    +==============:+:==============+:==================:+
    | Bananas       | $1.34         | built-in wrapper   |
    +---------------+---------------+--------------------+

For headerless tables, the colons go on the top line instead:

    +--------------:+:--------------+:------------------:+
    | Right         | Left          | Centered           |
    +---------------+---------------+--------------------+

##### Grid Table Limitations #####

Pandoc does not support grid tables with row spans or column spans.
This means that neither variable numbers of columns across rows nor
variable numbers of rows across columns are supported by Pandoc.
All grid tables must have the same number of columns in each row,
and the same number of rows in each column.  For example, the
Docutils [sample grid tables] will not render as expected with
Pandoc.

[sample grid tables]: http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#grid-tables


#### Extension: `pipe_tables` ####

Pipe tables look like this:

    | Right | Left | Default | Center |
    |------:|:-----|---------|:------:|
    |   12  |  12  |    12   |    12  |
    |  123  |  123 |   123   |   123  |
    |    1  |    1 |     1   |     1  |

      : Demonstration of pipe table syntax.

The syntax is identical to [PHP Markdown Extra tables].  The beginning and
ending pipe characters are optional, but pipes are required between all
columns.  The colons indicate column alignment as shown.  The header
cannot be omitted.  To simulate a headerless table, include a header
with blank cells.

Since the pipes indicate column boundaries, columns need not be vertically
aligned, as they are in the above example.  So, this is a perfectly
legal (though ugly) pipe table:

    fruit| price
    -----|-----:
    apple|2.05
    pear|1.37
    orange|3.09

The cells of pipe tables cannot contain block elements like paragraphs
and lists, and cannot span multiple lines.  If a pipe table contains a
row whose printable content is wider than the column width (see
`--columns`), then the cell contents will wrap, with the
relative cell widths determined by the widths of the separator
lines.  (In this case, the table will take up the full text
width.)  If no lines are wider than column width, then
cell contents will not be wrapped, and the cells will be sized
to their contents.

Note:  pandoc also recognizes pipe tables of the following
form, as can be produced by Emacs' orgtbl-mode:

    | One | Two   |
    |-----+-------|
    | my  | table |
    | is  | nice  |

The difference is that `+` is used instead of `|`. Other orgtbl features
are not supported. In particular, to get non-default column alignment,
you'll need to add colons as above.

[PHP Markdown Extra tables]: https://michelf.ca/projects/php-markdown/extra/#table

Metadata blocks
---------------

#### Extension: `pandoc_title_block` ####

If the file begins with a title block

    % title
    % author(s) (separated by semicolons)
    % date

it will be parsed as bibliographic information, not regular text.  (It
will be used, for example, in the title of standalone LaTeX or HTML
output.)  The block may contain just a title, a title and an author,
or all three elements. If you want to include an author but no
title, or a title and a date but no author, you need a blank line:

    %
    % Author

    % My title
    %
    % June 15, 2006

The title may occupy multiple lines, but continuation lines must
begin with leading space, thus:

    % My title
      on multiple lines

If a document has multiple authors, the authors may be put on
separate lines with leading space, or separated by semicolons, or
both.  So, all of the following are equivalent:

    % Author One
      Author Two

    % Author One; Author Two

    % Author One;
      Author Two

The date must fit on one line.

All three metadata fields may contain standard inline formatting
(italics, links, footnotes, etc.).

Title blocks will always be parsed, but they will affect the output only
when the `--standalone` (`-s`) option is chosen. In HTML output, titles
will appear twice: once in the document head -- this is the title that
will appear at the top of the window in a browser -- and once at the
beginning of the document body. The title in the document head can have
an optional prefix attached (`--title-prefix` or `-T` option). The title
in the body appears as an H1 element with class "title", so it can be
suppressed or reformatted with CSS. If a title prefix is specified with
`-T` and no title block appears in the document, the title prefix will
be used by itself as the HTML title.

The man page writer extracts a title, man page section number, and
other header and footer information from the title line. The title
is assumed to be the first word on the title line, which may optionally
end with a (single-digit) section number in parentheses. (There should
be no space between the title and the parentheses.)  Anything after
this is assumed to be additional footer and header text. A single pipe
character (`|`) should be used to separate the footer text from the header
text.  Thus,

    % PANDOC(1)

will yield a man page with the title `PANDOC` and section 1.

    % PANDOC(1) Pandoc User Manuals

will also have "Pandoc User Manuals" in the footer.

    % PANDOC(1) Pandoc User Manuals | Version 4.0

will also have "Version 4.0" in the header.

#### Extension: `yaml_metadata_block` ####

A YAML metadata block is a valid YAML object, delimited by a line of three
hyphens (`---`) at the top and a line of three hyphens (`---`) or three dots
(`...`) at the bottom.  A YAML metadata block may occur anywhere in the
document, but if it is not at the beginning, it must be preceded by a blank
line.  (Note that, because of the way pandoc concatenates input files when
several are provided, you may also keep the metadata in a separate YAML file
and pass it to pandoc as an argument, along with your Markdown files:

    pandoc chap1.md chap2.md chap3.md metadata.yaml -s -o book.html

Just be sure that the YAML file begins with `---` and ends with `---` or
`...`.)

Metadata will be taken from the fields of the YAML object and added to any
existing document metadata.  Metadata can contain lists and objects (nested
arbitrarily), but all string scalars will be interpreted as Markdown.  Fields
with names ending in an underscore will be ignored by pandoc.  (They may be
given a role by external processors.)

A document may contain multiple metadata blocks.  The metadata fields will
be combined through a *left-biased union*:  if two metadata blocks attempt
to set the same field, the value from the first block will be taken.

When pandoc is used with `-t markdown` to create a Markdown document,
a YAML metadata block will be produced only if the `-s/--standalone`
option is used.  All of the metadata will appear in a single block
at the beginning of the document.

Note that YAML escaping rules must be followed. Thus, for example,
if a title contains a colon, it must be quoted.  The pipe character
(`|`) can be used to begin an indented block that will be interpreted
literally, without need for escaping.  This form is necessary
when the field contains blank lines or block-level formatting:

    ---
    title:  'This is the title: it contains a colon'
    author:
    - Author One
    - Author Two
    tags: [nothing, nothingness]
    abstract: |
      This is the abstract.

      It consists of two paragraphs.
    ...

Template variables will be set automatically from the metadata.  Thus, for
example, in writing HTML, the variable `abstract` will be set to the HTML
equivalent of the Markdown in the `abstract` field:

    <p>This is the abstract.</p>
    <p>It consists of two paragraphs.</p>

Variables can contain arbitrary YAML structures, but the template must match
this structure.  The `author` variable in the default templates expects a
simple list or string, but can be changed to support more complicated
structures.  The following combination, for example, would add an affiliation
to the author if one is given:

    ---
    title: The document title
    author:
    - name: Author One
      affiliation: University of Somewhere
    - name: Author Two
      affiliation: University of Nowhere
    ...

To use the structured authors in the example above, you would need a custom
template:

    $for(author)$
    $if(author.name)$
    $author.name$$if(author.affiliation)$ ($author.affiliation$)$endif$
    $else$
    $author$
    $endif$
    $endfor$


Backslash escapes
-----------------

#### Extension: `all_symbols_escapable` ####

Except inside a code block or inline code, any punctuation or space
character preceded by a backslash will be treated literally, even if it
would normally indicate formatting.  Thus, for example, if one writes

    *\*hello\**

one will get

    <em>*hello*</em>

instead of

    <strong>hello</strong>

This rule is easier to remember than standard Markdown's rule,
which allows only the following characters to be backslash-escaped:

    \`*_{}[]()>#+-.!

(However, if the `markdown_strict` format is used, the standard Markdown rule
will be used.)

A backslash-escaped space is parsed as a nonbreaking space.  It will
appear in TeX output as `~` and in HTML and XML as `\&#160;` or
`\&nbsp;`.

A backslash-escaped newline (i.e. a backslash occurring at the end of
a line) is parsed as a hard line break.  It will appear in TeX output as
`\\` and in HTML as `<br />`.  This is a nice alternative to
Markdown's "invisible" way of indicating hard line breaks using
two trailing spaces on a line.

Backslash escapes do not work in verbatim contexts.

Inline formatting
-----------------

### Emphasis ###

To *emphasize* some text, surround it with `*`s or `_`, like this:

    This text is _emphasized with underscores_, and this
    is *emphasized with asterisks*.

Double `*` or `_` produces **strong emphasis**:

    This is **strong emphasis** and __with underscores__.

A `*` or `_` character surrounded by spaces, or backslash-escaped,
will not trigger emphasis:

    This is * not emphasized *, and \*neither is this\*.

#### Extension: `intraword_underscores` ####

Because `_` is sometimes used inside words and identifiers,
pandoc does not interpret a `_` surrounded by alphanumeric
characters as an emphasis marker.  If you want to emphasize
just part of a word, use `*`:

    feas*ible*, not feas*able*.


### Strikeout ###

#### Extension: `strikeout` ####

To strikeout a section of text with a horizontal line, begin and end it
with `~~`. Thus, for example,

    This ~~is deleted text.~~


### Superscripts and subscripts ###

#### Extension: `superscript`, `subscript` ####

Superscripts may be written by surrounding the superscripted text by `^`
characters; subscripts may be written by surrounding the subscripted
text by `~` characters.  Thus, for example,

    H~2~O is a liquid.  2^10^ is 1024.

If the superscripted or subscripted text contains spaces, these spaces
must be escaped with backslashes.  (This is to prevent accidental
superscripting and subscripting through the ordinary use of `~` and `^`.)
Thus, if you want the letter P with 'a cat' in subscripts, use
`P~a\ cat~`, not `P~a cat~`.


### Verbatim ###

To make a short span of text verbatim, put it inside backticks:

    What is the difference between `>>=` and `>>`?

If the verbatim text includes a backtick, use double backticks:

    Here is a literal backtick `` ` ``.

(The spaces after the opening backticks and before the closing
backticks will be ignored.)

The general rule is that a verbatim span starts with a string
of consecutive backticks (optionally followed by a space)
and ends with a string of the same number of backticks (optionally
preceded by a space).

Note that backslash-escapes (and other Markdown constructs) do not
work in verbatim contexts:

    This is a backslash followed by an asterisk: `\*`.

#### Extension: `inline_code_attributes` ####

Attributes can be attached to verbatim text, just as with
[fenced code blocks]:

    `<$>`{.haskell}

### Small caps ###

To write small caps, use the `smallcaps` class:

    [Small caps]{.smallcaps}

Or, without the `bracketed_spans` extension:

    <span class="smallcaps">Small caps</span>

For compatibility with other Markdown flavors, CSS is also supported:

    <span style="font-variant:small-caps;">Small caps</span>

This will work in all output formats that support small caps.


Math
----

#### Extension: `tex_math_dollars` ####

Anything between two `$` characters will be treated as TeX math.  The
opening `$` must have a non-space character immediately to its right,
while the closing `$` must have a non-space character immediately to its
left, and must not be followed immediately by a digit.  Thus,
`$20,000 and $30,000` won't parse as math.  If for some reason
you need to enclose text in literal `$` characters, backslash-escape
them and they won't be treated as math delimiters.

TeX math will be printed in all output formats. How it is rendered
depends on the output format:

Markdown, LaTeX, Emacs Org mode, ConTeXt, ZimWiki
  ~ It will appear verbatim between `$` characters.

reStructuredText
  ~ It will be rendered using an [interpreted text role `:math:`].

AsciiDoc
  ~ It will be rendered as `latexmath:[...]`.

Texinfo
  ~ It will be rendered inside a `@math` command.

groff man
  ~ It will be rendered verbatim without `$`'s.

MediaWiki, DokuWiki
  ~ It will be rendered inside `<math>` tags.

Textile
  ~ It will be rendered inside `<span class="math">` tags.

RTF, OpenDocument
  ~ It will be rendered, if possible, using Unicode characters,
    and will otherwise appear verbatim.

ODT
  ~ It will be rendered, if possible, using MathML.

DocBook
  ~ If the `--mathml` flag is used, it will be rendered using MathML
    in an `inlineequation` or `informalequation` tag.  Otherwise it
    will be rendered, if possible, using Unicode characters.

Docx
  ~ It will be rendered using OMML math markup.

FictionBook2
  ~ If the `--webtex` option is used, formulas are rendered as images
    using CodeCogs or other compatible web service, downloaded
    and embedded in the e-book. Otherwise, they will appear verbatim.

HTML, Slidy, DZSlides, S5, EPUB
  ~ The way math is rendered in HTML will depend on the
    command-line options selected. Therefore see [Math rendering in HTML]
    above.

[interpreted text role `:math:`]: http://docutils.sourceforge.net/docs/ref/rst/roles.html#math

Raw HTML
--------

#### Extension: `raw_html` ####

Markdown allows you to insert raw HTML (or DocBook) anywhere in a document
(except verbatim contexts, where `<`, `>`, and `&` are interpreted
literally).  (Technically this is not an extension, since standard
Markdown allows it, but it has been made an extension so that it can
be disabled if desired.)

The raw HTML is passed through unchanged in HTML, S5, Slidy, Slideous,
DZSlides, EPUB, Markdown, Emacs Org mode, and Textile output, and suppressed
in other formats.

#### Extension: `markdown_in_html_blocks` ####

Standard Markdown allows you to include HTML "blocks":  blocks
of HTML between balanced tags that are separated from the surrounding text
with blank lines, and start and end at the left margin.  Within
these blocks, everything is interpreted as HTML, not Markdown;
so (for example), `*` does not signify emphasis.

Pandoc behaves this way when the `markdown_strict` format is used; but
by default, pandoc interprets material between HTML block tags as Markdown.
Thus, for example, pandoc will turn

    <table>
    <tr>
    <td>*one*</td>
    <td>[a link](http://google.com)</td>
    </tr>
    </table>

into

    <table>
    <tr>
    <td><em>one</em></td>
    <td><a href="http://google.com">a link</a></td>
    </tr>
    </table>

whereas `Markdown.pl` will preserve it as is.

There is one exception to this rule:  text between `<script>` and
`<style>` tags is not interpreted as Markdown.

This departure from standard Markdown should make it easier to mix
Markdown with HTML block elements.  For example, one can surround
a block of Markdown text with `<div>` tags without preventing it
from being interpreted as Markdown.

#### Extension: `native_divs` ####

Use native pandoc `Div` blocks for content inside `<div>` tags.
For the most part this should give the same output as
`markdown_in_html_blocks`, but it makes it easier to write pandoc
filters to manipulate groups of blocks.

#### Extension: `native_spans` ####

Use native pandoc `Span` blocks for content inside `<span>` tags.
For the most part this should give the same output as `raw_html`,
but it makes it easier to write pandoc filters to manipulate groups
of inlines.

#### Extension: `raw_tex` ####

In addition to raw HTML, pandoc allows raw LaTeX, TeX, and ConTeXt to be
included in a document. Inline TeX commands will be preserved and passed
unchanged to the LaTeX and ConTeXt writers. Thus, for example, you can use
LaTeX to include BibTeX citations:

    This result was proved in \cite{jones.1967}.

Note that in LaTeX environments, like

    \begin{tabular}{|l|l|}\hline
    Age & Frequency \\ \hline
    18--25  & 15 \\
    26--35  & 33 \\
    36--45  & 22 \\ \hline
    \end{tabular}

the material between the begin and end tags will be interpreted as raw
LaTeX, not as Markdown.

Inline LaTeX is ignored in output formats other than Markdown, LaTeX,
Emacs Org mode, and ConTeXt.

### Generic raw attribute ###

#### Extension: `raw_attribute` ####

Inline spans and fenced code blocks with a special
kind of attribute will be parsed as raw content with the
designated format.  For example, the following produces a raw
groff `ms` block:

    ```{=ms}
    .MYMACRO
    blah blah
    ```
And the following produces a raw `html` inline element:

    This is `<a>html</a>`{=html}

The format name should match the target format name (see
`-t/--to`, above, for a list, or use `pandoc
--list-output-formats`).

This extension presupposes that the relevant kind of
inline code or fenced code block is enabled.  Thus, for
example, to use a raw attribute with a backtick code block,
`backtick_code_blocks` must be enabled.

The raw attribute cannot be combined with regular attributes.

LaTeX macros
------------

#### Extension: `latex_macros` ####

For output formats other than LaTeX, pandoc will parse LaTeX
macro definitions and apply the resulting macros to all LaTeX
math and raw LaTeX.  So, for example, the following will work in
all output formats, not just LaTeX:

    \newcommand{\tuple}[1]{\langle #1 \rangle}

    $\tuple{a, b, c}$

In LaTeX output, the macro definitions will not be passed
through as raw LaTeX.

When `latex_macros` is disabled, the macro definitions will
be passed through as raw LaTeX, and the raw LaTeX and math will
not have macros applied. This is usually a better approach when
you are targeting LaTeX or PDF.

Links
-----

Markdown allows links to be specified in several ways.

### Automatic links ###

If you enclose a URL or email address in pointy brackets, it
will become a link:

    <http://google.com>
    <sam@green.eggs.ham>

### Inline links ###

An inline link consists of the link text in square brackets,
followed by the URL in parentheses. (Optionally, the URL can
be followed by a link title, in quotes.)

    This is an [inline link](/url), and here's [one with
    a title](http://fsf.org "click here for a good time!").

There can be no space between the bracketed part and the parenthesized part.
The link text can contain formatting (such as emphasis), but the title cannot.

Email addresses in inline links are not autodetected, so they have to be
prefixed with `mailto`:

    [Write me!](mailto:sam@green.eggs.ham)

### Reference links ###

An *explicit* reference link has two parts, the link itself and the link
definition, which may occur elsewhere in the document (either
before or after the link).

The link consists of link text in square brackets, followed by a label in
square brackets. (There cannot be space between the two unless the
`spaced_reference_links` extension is enabled.) The link definition
consists of the bracketed label, followed by a colon and a space, followed by
the URL, and optionally (after a space) a link title either in quotes or in
parentheses.  The label must not be parseable as a citation (assuming
the `citations` extension is enabled):  citations take precedence over
link labels.

Here are some examples:

    [my label 1]: /foo/bar.html  "My title, optional"
    [my label 2]: /foo
    [my label 3]: http://fsf.org (The free software foundation)
    [my label 4]: /bar#special  'A title in single quotes'

The URL may optionally be surrounded by angle brackets:

    [my label 5]: <http://foo.bar.baz>

The title may go on the next line:

    [my label 3]: http://fsf.org
      "The free software foundation"

Note that link labels are not case sensitive.  So, this will work:

    Here is [my link][FOO]

    [Foo]: /bar/baz

In an *implicit* reference link, the second pair of brackets is
empty:

    See [my website][].

    [my website]: http://foo.bar.baz

Note:  In `Markdown.pl` and most other Markdown implementations,
reference link definitions cannot occur in nested constructions
such as list items or block quotes.  Pandoc lifts this arbitrary
seeming restriction.  So the following is fine in pandoc, though
not in most other implementations:

    > My block [quote].
    >
    > [quote]: /foo

#### Extension: `shortcut_reference_links` ####

In a *shortcut* reference link, the second pair of brackets may
be omitted entirely:

    See [my website].

    [my website]: http://foo.bar.baz

### Internal links ###

To link to another section of the same document, use the automatically
generated identifier (see [Header identifiers]). For example:

    See the [Introduction](#introduction).

or

    See the [Introduction].

    [Introduction]: #introduction

Internal links are currently supported for HTML formats (including
HTML slide shows and EPUB), LaTeX, and ConTeXt.

Images
------

A link immediately preceded by a `!` will be treated as an image.
The link text will be used as the image's alt text:

    ![la lune](lalune.jpg "Voyage to the moon")

    ![movie reel]

    [movie reel]: movie.gif

#### Extension: `implicit_figures` ####

An image with nonempty alt text, occurring by itself in a
paragraph, will be rendered as a figure with a caption.  The
image's alt text will be used as the caption.

    ![This is the caption](/url/of/image.png)

How this is rendered depends on the output format. Some output
formats (e.g. RTF) do not yet support figures.  In those
formats, you'll just get an image in a paragraph by itself, with
no caption.

If you just want a regular inline image, just make sure it is not
the only thing in the paragraph. One way to do this is to insert a
nonbreaking space after the image:

    ![This image won't be a figure](/url/of/image.png)\ 

Note that in reveal.js slide shows, an image in a paragraph
by itself that has the `stretch` class will fill the screen,
and the caption and figure tags will be omitted.

#### Extension: `link_attributes` ####

Attributes can be set on links and images:

    An inline ![image](foo.jpg){#id .class width=30 height=20px}
    and a reference ![image][ref] with attributes.

    [ref]: foo.jpg "optional title" {#id .class key=val key2="val 2"}

(This syntax is compatible with [PHP Markdown Extra] when only `#id`
and `.class` are used.)

For HTML and EPUB, all attributes except `width` and `height` (but
including `srcset` and `sizes`) are passed through as is. The other
writers ignore attributes that are not supported by their output
format.

The `width` and `height` attributes on images are treated specially. When
used without a unit, the unit is assumed to be pixels. However, any of
the following unit identifiers can be used: `px`, `cm`, `mm`, `in`, `inch`
and `%`. There must not be any spaces between the number and the unit.
For example:

```
![](file.jpg){ width=50% }
```

- Dimensions are converted to inches for output in page-based formats like
  LaTeX. Dimensions are converted to pixels for output in HTML-like
  formats.  Use the `--dpi` option to specify the number of pixels per
  inch.  The default is 96dpi.
- The `%` unit is generally relative to some available space.
  For example the above example will render to
  `<img href="file.jpg" style="width: 50%;" />` (HTML),
  `\includegraphics[width=0.5\textwidth]{file.jpg}` (LaTeX), or
  `\externalfigure[file.jpg][width=0.5\textwidth]` (ConTeXt).
- Some output formats have a notion of a class
  ([ConTeXt](http://wiki.contextgarden.net/Using_Graphics#Multiple_Image_Settings))
  or a unique identifier (LaTeX `\caption`), or both (HTML).
- When no `width` or `height` attributes are specified, the fallback
  is to look at the image resolution and the dpi metadata embedded in
  the image file.

Divs and Spans
--------------

Using the `native_divs` and `native_spans` extensions
(see [above][Extension: `native_divs`]), HTML syntax can
be used as part of markdown to create native `Div` and `Span`
elements in the pandoc AST (as opposed to raw HTML).
However, there is also nicer syntax available:

#### Extension: `fenced_divs` ####

Allow special fenced syntax for native `Div` blocks.  A Div
starts with a fence containing at least three consecutive
colons plus some attributes. The attributes may optionally
be followed by another string of consecutive colons.
The attribute syntax is exactly as in fenced code blocks (see
[Extension: `fenced_code_attributes`]).  As with fenced
code blocks, one can use either attributes in curly braces
or a single unbraced word, which will be treated as a class
name.  The Div ends with another line containing a string of at
least three consecutive colons.  The fenced Div should be
separated by blank lines from preceding and following blocks.

Example:

    ::::: {#special .sidebar}
    Here is a paragraph.

    And another.
    :::::

Fenced divs can be nested.  Opening fences are distinguished
because they *must* have attributes:

    ::: Warning ::::::
    This is a warning.

    ::: Danger
    This is a warning within a warning.
    :::
    ::::::::::::::::::

Fences without attributes are always closing fences.  Unlike
with fenced code blocks, the number of colons in the closing
fence need not match the number in the opening fence.  However,
it can be helpful for visual clarity to use fences of different
lengths to distinguish nested divs from their parents.


#### Extension: `bracketed_spans` ####

A bracketed sequence of inlines, as one would use to begin
a link, will be treated as a `Span` with attributes if it is
followed immediately by attributes:

    [This is *some text*]{.class key="val"}

Footnotes
---------

#### Extension: `footnotes` ####

Pandoc's Markdown allows footnotes, using the following syntax:

    Here is a footnote reference,[^1] and another.[^longnote]

    [^1]: Here is the footnote.

    [^longnote]: Here's one with multiple blocks.

        Subsequent paragraphs are indented to show that they
    belong to the previous footnote.

            { some.code }

        The whole paragraph can be indented, or just the first
        line.  In this way, multi-paragraph footnotes work like
        multi-paragraph list items.

    This paragraph won't be part of the note, because it
    isn't indented.

The identifiers in footnote references may not contain spaces, tabs,
or newlines.  These identifiers are used only to correlate the
footnote reference with the note itself; in the output, footnotes
will be numbered sequentially.

The footnotes themselves need not be placed at the end of the
document.  They may appear anywhere except inside other block elements
(lists, block quotes, tables, etc.).  Each footnote should be
separated from surrounding content (including other footnotes)
by blank lines.

#### Extension: `inline_notes` ####

Inline footnotes are also allowed (though, unlike regular notes,
they cannot contain multiple paragraphs).  The syntax is as follows:

    Here is an inline note.^[Inlines notes are easier to write, since
    you don't have to pick an identifier and move down to type the
    note.]

Inline and regular footnotes may be mixed freely.

Citations
---------

#### Extension: `citations` ####

Using an external filter, `pandoc-citeproc`, pandoc can automatically generate
citations and a bibliography in a number of styles.  Basic usage is

    pandoc --filter pandoc-citeproc myinput.txt

In order to use this feature, you will need to specify a bibliography file
using the `bibliography` metadata field in a YAML metadata section, or
`--bibliography` command line argument. You can supply multiple `--bibliography`
arguments or set `bibliography` metadata field to YAML array, if you want to
use multiple bibliography files.  The bibliography may have any of these
formats:

  Format            File extension
  ------------      --------------
  BibLaTeX          .bib
  BibTeX            .bibtex
  Copac             .copac
  CSL JSON          .json
  CSL YAML          .yaml
  EndNote           .enl
  EndNote XML       .xml
  ISI               .wos
  MEDLINE           .medline
  MODS              .mods
  RIS               .ris

Note that `.bib` can be used with both BibTeX and BibLaTeX files;
use `.bibtex` to force BibTeX.

Note that `pandoc-citeproc --bib2json` and `pandoc-citeproc --bib2yaml`
can produce `.json` and `.yaml` files from any of the supported formats.

In-field markup: In BibTeX and BibLaTeX databases, pandoc-citeproc parses
a subset of LaTeX markup; in CSL YAML databases, pandoc Markdown; and in CSL JSON databases, an [HTML-like markup][CSL markup specs]:

`<i>...</i>`
:   italics

`<b>...</b>`
:   bold

`<span style="font-variant:small-caps;">...</span>` or `<sc>...</sc>`
:   small capitals

`<sub>...</sub>`
:   subscript

`<sup>...</sup>`
:   superscript

`<span class="nocase">...</span>`
:   prevent a phrase from being capitalized as title case

`pandoc-citeproc -j` and `-y` interconvert the CSL JSON
and CSL YAML formats as far as possible.

As an alternative to specifying a bibliography file using `--bibliography`
or the YAML metadata field `bibliography`, you can include
the citation data directly in the `references` field of the
document's YAML metadata. The field should contain an array of
YAML-encoded references, for example:

    ---
    references:
    - type: article-journal
      id: WatsonCrick1953
      author:
      - family: Watson
        given: J. D.
      - family: Crick
        given: F. H. C.
      issued:
        date-parts:
        - - 1953
          - 4
          - 25
      title: 'Molecular structure of nucleic acids: a structure for deoxyribose
        nucleic acid'
      title-short: Molecular structure of nucleic acids
      container-title: Nature
      volume: 171
      issue: 4356
      page: 737-738
      DOI: 10.1038/171737a0
      URL: http://www.nature.com/nature/journal/v171/n4356/abs/171737a0.html
      language: en-GB
    ...

(`pandoc-citeproc --bib2yaml` can produce these from a bibliography file in one
of the supported formats.)

Citations and references can be formatted using any style supported by the
[Citation Style Language], listed in the [Zotero Style Repository].
These files are specified using the `--csl` option or the `csl` metadata field.
By default, `pandoc-citeproc` will use the [Chicago Manual of Style] author-date
format.  The CSL project provides further information on [finding and editing styles].

To make your citations hyperlinks to the corresponding bibliography
entries, add `link-citations: true` to your YAML metadata.

Citations go inside square brackets and are separated by semicolons.
Each citation must have a key, composed of '@' + the citation
identifier from the database, and may optionally have a prefix,
a locator, and a suffix.  The citation key must begin with a letter, digit,
or `_`, and may contain alphanumerics, `_`, and internal punctuation
characters (`:.#$%&-+?<>~/`).  Here are some examples:

    Blah blah [see @doe99, pp. 33-35; also @smith04, chap. 1].

    Blah blah [@doe99, pp. 33-35, 38-39 and *passim*].

    Blah blah [@smith04; @doe99].

`pandoc-citeproc` detects locator terms in the [CSL locale files].
Either abbreviated or unabbreviated forms are accepted. In the `en-US`
locale, locator terms can be written in either singular or plural forms,
as `book`, `bk.`/`bks.`; `chapter`, `chap.`/`chaps.`; `column`,
`col.`/`cols.`; `figure`, `fig.`/`figs.`; `folio`, `fol.`/`fols.`;
`number`, `no.`/`nos.`; `line`, `l.`/`ll.`; `note`, `n.`/`nn.`; `opus`,
`op.`/`opp.`; `page`, `p.`/`pp.`; `paragraph`, `para.`/`paras.`; `part`,
`pt.`/`pts.`; `section`, `sec.`/`secs.`; `sub verbo`, `s.v.`/`s.vv.`;
`verse`, `v.`/`vv.`; `volume`, `vol.`/`vols.`; `¶`/`¶¶`; `§`/`§§`. If no
locator term is used, "page" is assumed.

A minus sign (`-`) before the `@` will suppress mention of
the author in the citation.  This can be useful when the
author is already mentioned in the text:

    Smith says blah [-@smith04].

You can also write an in-text citation, as follows:

    @smith04 says blah.

    @smith04 [p. 33] says blah.

If the style calls for a list of works cited, it will be placed
at the end of the document.  Normally, you will want to end your
document with an appropriate header:

    last paragraph...

    # References

The bibliography will be inserted after this header.  Note that
the `unnumbered` class will be added to this header, so that the
section will not be numbered.

If you want to include items in the bibliography without actually
citing them in the body text, you can define a dummy `nocite` metadata
field and put the citations there:

    ---
    nocite: |
      @item1, @item2
    ...

    @item3

In this example, the document will contain a citation for `item3`
only, but the bibliography will contain entries for `item1`, `item2`, and
`item3`.

It is possible to create a bibliography with all the citations,
whether or not they appear in the document, by using a wildcard:

    ---
    nocite: |
      @*
    ...

For LaTeX or PDF output, you can also use [`natbib`] or [`biblatex`]
to render bibliography. In order to do so, specify bibliography files as
outlined above, and add `--natbib` or `--biblatex` argument to `pandoc`
invocation. Bear in mind that bibliography files have to be in respective
format (either BibTeX or BibLaTeX).

For more information, see the [pandoc-citeproc man page].

[CSL markup specs]: http://docs.citationstyles.org/en/1.0/release-notes.html#rich-text-markup-within-fields
[Chicago Manual of Style]: http://chicagomanualofstyle.org
[Citation Style Language]: http://citationstyles.org
[Zotero Style Repository]: https://www.zotero.org/styles
[finding and editing styles]: http://citationstyles.org/styles/
[CSL locale files]: https://github.com/citation-style-language/locales
[pandoc-citeproc man page]: https://github.com/jgm/pandoc-citeproc/blob/master/man/pandoc-citeproc.1.md

Non-pandoc extensions
---------------------

The following Markdown syntax extensions are not enabled by default
in pandoc, but may be enabled by adding `+EXTENSION` to the format
name, where `EXTENSION` is the name of the extension.  Thus, for
example, `markdown+hard_line_breaks` is Markdown with hard line breaks.

#### Extension: `old_dashes` ####

Selects the pandoc <= 1.8.2.1 behavior for parsing smart dashes:
`-` before a numeral is an en-dash, and `--` is an em-dash.
This option only has an effect if `smart` is enabled. It is
selected automatically for `textile` input.

#### Extension: `angle_brackets_escapable` ####

Allow `<` and `>` to be backslash-escaped, as they can be in
GitHub flavored Markdown but not original Markdown.  This is
implied by pandoc's default `all_symbols_escapable`.

#### Extension: `lists_without_preceding_blankline` ####

Allow a list to occur right after a paragraph, with no intervening
blank space.

#### Extension: `four_space_rule` ####

Selects the pandoc <= 2.0 behavior for parsing lists, so that
four spaces indent are needed for list item continuation
paragraphs.

#### Extension: `spaced_reference_links` ####

Allow whitespace between the two components of a reference link,
for example,

    [foo] [bar].

#### Extension: `hard_line_breaks` ####

Causes all newlines within a paragraph to be interpreted as hard line
breaks instead of spaces.

#### Extension: `ignore_line_breaks` ####

Causes newlines within a paragraph to be ignored, rather than being
treated as spaces or as hard line breaks.  This option is intended for
use with East Asian languages where spaces are not used between words,
but text is divided into lines for readability.

#### Extension: `east_asian_line_breaks` ####

Causes newlines within a paragraph to be ignored, rather than
being treated as spaces or as hard line breaks, when they occur
between two East Asian wide characters.  This is a better choice
than `ignore_line_breaks` for texts that include a mix of East
Asian wide characters and other characters.

#### Extension: `emoji` ####

Parses textual emojis like `:smile:` as Unicode emoticons.

#### Extension: `tex_math_single_backslash` ####

Causes anything between `\(` and `\)` to be interpreted as inline
TeX math, and anything between `\[` and `\]` to be interpreted
as display TeX math.  Note: a drawback of this extension is that
it precludes escaping `(` and `[`.

#### Extension: `tex_math_double_backslash` ####

Causes anything between `\\(` and `\\)` to be interpreted as inline
TeX math, and anything between `\\[` and `\\]` to be interpreted
as display TeX math.

#### Extension: `markdown_attribute` ####

By default, pandoc interprets material inside block-level tags as Markdown.
This extension changes the behavior so that Markdown is only parsed
inside block-level tags if the tags have the attribute `markdown=1`.

#### Extension: `mmd_title_block` ####

Enables a [MultiMarkdown] style title block at the top of
the document, for example:

    Title:   My title
    Author:  John Doe
    Date:    September 1, 2008
    Comment: This is a sample mmd title block, with
             a field spanning multiple lines.

See the MultiMarkdown documentation for details.  If `pandoc_title_block` or
`yaml_metadata_block` is enabled, it will take precedence over
`mmd_title_block`.

#### Extension: `abbreviations` ####

Parses PHP Markdown Extra abbreviation keys, like

    *[HTML]: Hypertext Markup Language

Note that the pandoc document model does not support
abbreviations, so if this extension is enabled, abbreviation keys are
simply skipped (as opposed to being parsed as paragraphs).

#### Extension: `autolink_bare_uris` ####

Makes all absolute URIs into links, even when not surrounded by
pointy braces `<...>`.

#### Extension: `mmd_link_attributes` ####

Parses multimarkdown style key-value attributes on link
and image references. This extension should not be confused with the
[`link_attributes`](#extension-link_attributes) extension.

    This is a reference ![image][ref] with multimarkdown attributes.

    [ref]: http://path.to/image "Image title" width=20px height=30px
           id=myId class="myClass1 myClass2"

#### Extension: `mmd_header_identifiers` ####

Parses multimarkdown style header identifiers (in square brackets,
after the header but before any trailing `#`s in an ATX header).

#### Extension: `compact_definition_lists` ####

Activates the definition list syntax of pandoc 1.12.x and earlier.
This syntax differs from the one described above under [Definition lists]
in several respects:

  - No blank line is required between consecutive items of the
    definition list.
  - To get a "tight" or "compact" list, omit space between consecutive
    items; the space between a term and its definition does not affect
    anything.
  - Lazy wrapping of paragraphs is not allowed:  the entire definition must
    be indented four spaces.[^6]

[^6]:  To see why laziness is incompatible with relaxing the requirement
    of a blank line between items, consider the following example:

        bar
        :    definition
        foo
        :    definition

    Is this a single list item with two definitions of "bar," the first of
    which is lazily wrapped, or two list items?  To remove the ambiguity
    we must either disallow lazy wrapping or require a blank line between
    list items.

Markdown variants
-----------------

In addition to pandoc's extended Markdown, the following Markdown
variants are supported:

`markdown_phpextra` (PHP Markdown Extra)
:   `footnotes`, `pipe_tables`, `raw_html`, `markdown_attribute`,
    `fenced_code_blocks`, `definition_lists`, `intraword_underscores`,
    `header_attributes`, `link_attributes`, `abbreviations`,
    `shortcut_reference_links`, `spaced_reference_links`.

`markdown_github` (deprecated GitHub-Flavored Markdown)
:   `pipe_tables`, `raw_html`, `fenced_code_blocks`, `gfm_auto_identifiers`,
    `ascii_identifiers`, `backtick_code_blocks`, `autolink_bare_uris`,
    `space_in_atx_header`, `intraword_underscores`, `strikeout`,
    `emoji`, `shortcut_reference_links`, `angle_brackets_escapable`,
    `lists_without_preceding_blankline`.

`markdown_mmd` (MultiMarkdown)
:   `pipe_tables`, `raw_html`, `markdown_attribute`, `mmd_link_attributes`,
    `tex_math_double_backslash`, `intraword_underscores`,
    `mmd_title_block`, `footnotes`, `definition_lists`,
    `all_symbols_escapable`, `implicit_header_references`,
    `auto_identifiers`, `mmd_header_identifiers`,
    `shortcut_reference_links`, `implicit_figures`,
    `superscript`, `subscript`, `backtick_code_blocks`,
    `spaced_reference_links`, `raw_attribute`.

`markdown_strict` (Markdown.pl)
:   `raw_html`, `shortcut_reference_links`,
    `spaced_reference_links`.

We also support `commonmark` and `gfm` (GitHub-Flavored Markdown,
which is implemented as a set of extensions on `commonmark`).

Note, however, that `commonmark` and `gfm` have limited support
for extensions. Only those  listed below (and `smart` and
`raw_tex`) will work. The extensions can, however, all be
individually disabled.
Also, `raw_tex` only affects `gfm` output, not input.

`gfm` (GitHub-Flavored Markdown)
:   `pipe_tables`, `raw_html`, `fenced_code_blocks`, `auto_identifiers`,
    `ascii_identifiers`, `backtick_code_blocks`, `autolink_bare_uris`,
    `intraword_underscores`, `strikeout`, `hard_line_breaks`, `emoji`,
    `shortcut_reference_links`, `angle_brackets_escapable`.

Producing slide shows with pandoc
=================================

You can use pandoc to produce an HTML + JavaScript slide presentation
that can be viewed via a web browser.  There are five ways to do this,
using [S5], [DZSlides], [Slidy], [Slideous], or [reveal.js].
You can also produce a PDF slide show using LaTeX [`beamer`], or
slides shows in Microsoft [PowerPoint] format.

Here's the Markdown source for a simple slide show, `habits.txt`:

    % Habits
    % John Doe
    % March 22, 2005

    # In the morning

    ## Getting up

    - Turn off alarm
    - Get out of bed

    ## Breakfast

    - Eat eggs
    - Drink coffee

    # In the evening

    ## Dinner

    - Eat spaghetti
    - Drink wine

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

    ![picture of spaghetti](images/spaghetti.jpg)

    ## Going to sleep

    - Get in bed
    - Count sheep

To produce an HTML/JavaScript slide show, simply type

    pandoc -t FORMAT -s habits.txt -o habits.html

where `FORMAT` is either `s5`, `slidy`, `slideous`, `dzslides`, or `revealjs`.

For Slidy, Slideous, reveal.js, and S5, the file produced by pandoc with the
`-s/--standalone` option embeds a link to JavaScript and CSS files, which are
assumed to be available at the relative path `s5/default` (for S5), `slideous`
(for Slideous), `reveal.js` (for reveal.js), or at the Slidy website at
`w3.org` (for Slidy).  (These paths can be changed by setting the `slidy-url`,
`slideous-url`, `revealjs-url`, or `s5-url` variables; see [Variables for slides],
above.) For DZSlides, the (relatively short) JavaScript and CSS are included in
the file by default.

With all HTML slide formats, the `--self-contained` option can be used to
produce a single file that contains all of the data necessary to display the
slide show, including linked scripts, stylesheets, images, and videos.

To produce a PDF slide show using beamer, type

    pandoc -t beamer habits.txt -o habits.pdf

Note that a reveal.js slide show can also be converted to a PDF
by printing it to a file from the browser.

To produce a Powerpoint slide show, type

    pandoc habits.txt -o habits.pptx

Structuring the slide show
--------------------------

By default, the *slide level* is the highest header level in
the hierarchy that is followed immediately by content, and not another
header, somewhere in the document. In the example above, level 1 headers
are always followed by level 2 headers, which are followed by content,
so 2 is the slide level.  This default can be overridden using
the `--slide-level` option.

The document is carved up into slides according to the following
rules:

  * A horizontal rule always starts a new slide.

  * A header at the slide level always starts a new slide.

  * Headers *below* the slide level in the hierarchy create
    headers *within* a slide.

  * Headers *above* the slide level in the hierarchy create
    "title slides," which just contain the section title
    and help to break the slide show into sections.

  * Content *above* the slide level will not appear in the slide
    show.

  * A title page is constructed automatically from the document's title
    block, if present.  (In the case of beamer, this can be disabled
    by commenting out some lines in the default template.)

These rules are designed to support many different styles of slide show. If
you don't care about structuring your slides into sections and subsections,
you can just use level 1 headers for all each slide. (In that case, level 1
will be the slide level.) But you can also structure the slide show into
sections, as in the example above.

Note:  in reveal.js slide shows, if slide level is 2, a two-dimensional
layout will be produced, with level 1 headers building horizontally
and level 2 headers building vertically.  It is not recommended that
you use deeper nesting of section levels with reveal.js.

Incremental lists
-----------------

By default, these writers produce lists that display "all at once."
If you want your lists to display incrementally (one item at a time),
use the `-i` option. If you want a particular list to depart from the
default (that is, to display incrementally without the `-i` option and
all at once with the `-i` option), put it in a block quote:

    > - Eat spaghetti
    > - Drink wine

In this way incremental and nonincremental lists can be mixed in
a single document.

Inserting pauses
----------------

You can add "pauses" within a slide by including a paragraph containing
three dots, separated by spaces:

    # Slide with a pause

    content before the pause

    . . .

    content after the pause

Styling the slides
------------------

You can change the style of HTML slides by putting customized CSS files
in `$DATADIR/s5/default` (for S5), `$DATADIR/slidy` (for Slidy),
or `$DATADIR/slideous` (for Slideous),
where `$DATADIR` is the user data directory (see `--data-dir`, above).
The originals may be found in pandoc's system data directory (generally
`$CABALDIR/pandoc-VERSION/s5/default`). Pandoc will look there for any
files it does not find in the user data directory.

For dzslides, the CSS is included in the HTML file itself, and may
be modified there.

All [reveal.js configuration options] can be set through variables.
For example, themes can be used by setting the `theme` variable:

    -V theme=moon

Or you can specify a custom stylesheet using the `--css` option.

To style beamer slides, you can specify a `theme`, `colortheme`,
`fonttheme`, `innertheme`, and `outertheme`, using the `-V` option:

    pandoc -t beamer habits.txt -V theme:Warsaw -o habits.pdf

Note that header attributes will turn into slide attributes
(on a `<div>` or `<section>`) in HTML slide formats, allowing you
to style individual slides.  In beamer, the only header attribute
that affects slides is the `allowframebreaks` class, which sets the
`allowframebreaks` option, causing multiple slides to be created
if the content overfills the frame.  This is recommended especially for
bibliographies:

    # References {.allowframebreaks}

Speaker notes
-------------

reveal.js has good support for speaker notes.  You can add notes to your
Markdown document thus:

    ::: notes

    This is my note.

    - It can contain Markdown
    - like this list

    :::

To show the notes window, press `s` while viewing the presentation.
Notes are not yet supported for other slide formats, but the notes
will not appear on the slides themselves.

Columns
-------

To put material in side by side columns, you can use a native
div container with class `columns`, containing two or more div
containers with class `column` and a `width` attribute:

    :::::::::::::: {.columns}
    ::: {.column width="40%"}
    contents...
    :::
    ::: {.column width="60%"}
    contents...
    :::
    ::::::::::::::

Frame attributes in beamer
--------------------------

Sometimes it is necessary to add the LaTeX `[fragile]` option to
a frame in beamer (for example, when using the `minted` environment).
This can be forced by adding the `fragile` class to the header
introducing the slide:

    # Fragile slide {.fragile}

All of the other frame attributes described in Section 8.1 of
the [Beamer User's Guide] may also be used: `allowdisplaybreaks`,
`allowframebreaks`, `b`, `c`, `t`, `environment`, `label`, `plain`,
`shrink`.

Creating EPUBs with pandoc
==========================

EPUB Metadata
-------------

EPUB metadata may be specified using the `--epub-metadata` option, but
if the source document is Markdown, it is better to use a [YAML metadata
block][Extension: `yaml_metadata_block`].  Here is an example:

    ---
    title:
    - type: main
      text: My Book
    - type: subtitle
      text: An investigation of metadata
    creator:
    - role: author
      text: John Smith
    - role: editor
      text: Sarah Jones
    identifier:
    - scheme: DOI
      text: doi:10.234234.234/33
    publisher:  My Press
    rights: © 2007 John Smith, CC BY-NC
    ibooks:
      version: 1.3.4
    ...

The following fields are recognized:

`identifier`
  ~ Either a string value or an object with fields `text` and
    `scheme`.  Valid values for `scheme` are `ISBN-10`,
    `GTIN-13`, `UPC`, `ISMN-10`, `DOI`, `LCCN`, `GTIN-14`,
    `ISBN-13`, `Legal deposit number`, `URN`, `OCLC`,
    `ISMN-13`, `ISBN-A`, `JP`, `OLCC`.

`title`
  ~ Either a string value, or an object with fields `file-as` and
    `type`, or a list of such objects.  Valid values for `type` are
    `main`, `subtitle`, `short`, `collection`, `edition`, `extended`.

`creator`
  ~ Either a string value, or an object with fields `role`, `file-as`,
    and `text`, or a list of such objects.  Valid values for `role` are
    [MARC relators], but
    pandoc will attempt to translate the human-readable versions
    (like "author" and "editor") to the appropriate marc relators.

`contributor`
  ~ Same format as `creator`.

`date`
  ~ A string value in `YYYY-MM-DD` format.  (Only the year is necessary.)
    Pandoc will attempt to convert other common date formats.

`lang` (or legacy: `language`)
  ~ A string value in [BCP 47] format.  Pandoc will default to the local
    language if nothing is specified.

`subject`
  ~ A string value or a list of such values.

`description`
  ~ A string value.

`type`
  ~ A string value.

`format`
  ~ A string value.

`relation`
  ~ A string value.

`coverage`
  ~ A string value.

`rights`
  ~ A string value.

`cover-image`
  ~ A string value (path to cover image).

`stylesheet`
  ~ A string value (path to CSS stylesheet).

`page-progression-direction`
  ~ Either `ltr` or `rtl`. Specifies the `page-progression-direction`
    attribute for the [`spine` element].

`ibooks`
  ~ iBooks-specific metadata, with the following fields:

    - `version`: (string)
    - `specified-fonts`: `true`|`false` (default `false`)
    - `ipad-orientation-lock`: `portrait-only`|`landscape-only`
    - `iphone-orientation-lock`: `portrait-only`|`landscape-only`
    - `binding`: `true`|`false` (default `true`)
    - `scroll-axis`: `vertical`|`horizontal`|`default`

[MARC relators]: http://loc.gov/marc/relators/relaterm.html
[`spine` element]: http://idpf.org/epub/301/spec/epub-publications.html#sec-spine-elem

Linked media
------------

By default, pandoc will download linked media (including audio and
video) and include it in the EPUB container, yielding a completely
self-contained EPUB.  If you want to link to external media resources
instead, use raw HTML in your source and add `data-external="1"` to the tag
with the `src` attribute.  For example:

    <audio controls="1">
      <source src="http://example.com/music/toccata.mp3"
              data-external="1" type="audio/mpeg">
      </source>
    </audio>

Syntax highlighting
===================

Pandoc will automatically highlight syntax in [fenced code blocks] that
are marked with a language name.  The Haskell library [skylighting] is
used for highlighting, which works in HTML, Docx, Ms, and LaTeX/PDF output.
To see a list of language names that pandoc will recognize, type
`pandoc --list-highlight-languages`.

The color scheme can be selected using the `--highlight-style` option.
The default color scheme is `pygments`, which imitates the default color
scheme used by the Python library pygments (though pygments is not actually
used to do the highlighting).  To see a list of highlight styles,
type `pandoc --list-highlight-styles`.

To disable highlighting, use the `--no-highlight` option.

[skylighting]: https://github.com/jgm/skylighting

Custom Styles in Docx Output
============================

By default, pandoc's docx output applies a predefined set of styles for
blocks such as paragraphs and block quotes, and uses largely default
formatting (italics, bold) for inlines. This will work for most
purposes, especially alongside a `reference.docx` file. However, if you
need to apply your own styles to blocks, or match a preexisting set of
styles, pandoc allows you to define custom styles for blocks and text
using `div`s and `span`s, respectively.

If you define a `div` or `span` with the attribute `custom-style`,
pandoc will apply your specified style to the contained elements. So,
for example using the `bracketed_spans` syntax,

    [Get out]{custom-style="Emphatically"}, he said.

would produce a docx file with "Get out" styled with character
style `Emphatically`. Similarly, using the `fenced_divs` syntax,

    Dickinson starts the poem simply:

    ::: {custom-style="Poetry"}
    | A Bird came down the Walk---
    | He did not know I saw---
    :::

would style the two contained lines with the `Poetry` paragraph style.

If the styles are not yet in your reference.docx, they will be defined
in the output file as inheriting from normal text. If they are already
defined, pandoc will not alter the definition.

This feature allows for greatest customization in conjunction with
[pandoc filters]. If you want all paragraphs after block quotes to be
indented, you can write a filter to apply the styles necessary. If you
want all italics to be transformed to the `Emphasis` character style
(perhaps to change their color), you can write a filter which will
transform all italicized inlines to inlines within an `Emphasis`
custom-style `span`.

[pandoc filters]: http://pandoc.org/filters.html

Custom writers
==============

Pandoc can be extended with custom writers written in [lua].  (Pandoc
includes a lua interpreter, so lua need not be installed separately.)

To use a custom writer, simply specify the path to the lua script
in place of the output format. For example:

    pandoc -t data/sample.lua

Creating a custom writer requires writing a lua function for each
possible element in a pandoc document.  To get a documented example
which you can modify according to your needs, do

    pandoc --print-default-data-file sample.lua

[lua]: http://www.lua.org

Authors
=======

Copyright 2006-2017 John MacFarlane (jgm@berkeley.edu). Released
under the [GPL], version 2 or greater.  This software carries no
warranty of any kind.  (See COPYRIGHT for full copyright and
warranty notices.) For a full list of contributors, see the file
AUTHORS.md in the pandoc source code.

[GPL]: http://www.gnu.org/copyleft/gpl.html "GNU General Public License"