path: root/doc/org.md

---
title: Org-mode features and differences
author: Albert Krewinkel
---

Pandoc's handling of org files is similar to that of Emacs
org-mode. This document aims to highlight the cases where this is
not possible or just not the case yet.

Export options
==============

The following export keywords are supported:

- AUTHOR: comma-separated list of author(s); fully supported.

- CREATOR: output generator; passed as plain-text metadata entry
  `creator`, but not used by any default templates.

- DATE: creation or publication date; well supported by pandoc.

- EMAIL: author email address; passed as plain-text metadata
  field `email`, but not used by any default templates.

- LANGUAGE: document language; included as plain-text metadata
  field `lang`. The value should be a [BCP47 language tag].

- SELECT_TAGS: tags which select a tree for export. Currently
  *unsupported*.

- EXCLUDE\_TAGS: tags which prevent a subtree from being
  exported. Fully supported.

- TITLE: document title; fully supported.

- EXPORT\_FILE\_NAME: target filename; *unsupported*, the output
  defaults to stdout unless a target has to be given as a command
  line option.

[BCP47 language tag]: https://tools.ietf.org/html/bcp47

Format-specific options
-----------------------

Emacs Org-mode supports additional export options which work for
specific export formats. Some of these options' behavior differs
in Org-mode depending on the output format, while pandoc is
format-agnostic when parsing; differences are noted where they
occur.

- DESCRIPTION: the document's description; pandoc parses this
  option as text with markup into the `description` metadata
  field. The field is not used in default templates.

  Pandoc follows the LaTeX exporter in that it allows markup in
  the description. In contrast, the Org-mode HTML exporter treats
  the description as plain text.

- LATEX\_HEADER and LATEX_HEADER_EXTRA: arbitrary lines to add to
  the document's preamble. Contrary to Org-mode, these lines are
  not inserted before the hyperref settings, but close to the end
  of the preamble.

  The contents of this option are stored as a list of raw LaTeX
  lines in the `header-includes` metadata field.

- LATEX\_CLASS: the LaTeX document class; like Org-mode, pandoc
  uses `article` as the default class.

  The contents of this option are stored as plain text in the
  `documentclass` metadata field.

- LATEX\_CLASS\_OPTIONS: Options for the LaTeX document class;
  fully supported.

  The contents of this option are stored as plain text in the
  `classoption` metadata field.

- SUBTITLE: the document's subtitle; fully supported.

  The content of this option is stored as inlines in the
  `subtitle` metadata field.

- HTML\_HEAD and HTML\_HEAD\_EXTRA: arbitrary lines to add to the
  HTML document's head; fully supported.

  The contents of these options are stored as a list of raw HTML
  lines in the `header-includes` metadata field.

Pandoc-specific options
-----------------------

Pandoc recognizes some export options not used by Emacs Org.

- NOCITE: this field adds the listed citations to the
  bibliography, without the need to mention them to the text. The
  special value `@*` causes all available references to be added
  the bibliography.

- HEADER-INCLUDES: like HTML_HEAD and, LATEX_HEADER, but treats
  the option's value as normal text with markup.

- INSTITUTE: Affiliation of the author; the value is read as text
  with markup and is stored in the `institute` metadata field. The
  field is included by default on the title slide of beamer
  presentations.

Other options
-------------

Any export option or directive not listed above has no effect when
parsing with pandoc. However, the information is retained as a
*raw block*. It can be accessed through a
[filter](https://pandoc.org/filters.html) and will be included in
org output.

### Directives as metadata

As an example, we will restore an old behavior of pandoc versions
prior to 2.10. Unknown keywords were treated as variable
definitions, and were added the document's metadata. Typing
`#+key: value` in the org-file used to have the same effect as
running pandoc with the `--metadata key=value` option.

Since pandoc 2.10, each unhandled line starting with `#+` is kept
internally as a raw block with format `org`. This block can be
inspected and processed by a filter. Below is a [Lua
filter](https://pandoc.org/lua-filters.html) which converts these
unhandled lines into metadata key-value pairs.

``` lua
-- intermediate store for variables and their values
local variables = {}

--- Function called for each raw block element.
function RawBlock (raw)
  -- Don't do anything unless the block contains *org* markup.
  if raw.format ~= 'org' then return nil end

  -- extract variable name and value
  local name, value = raw.text:match '#%+(%w+):%s*(.+)$'
  if name and value then
    variables[name] = value
  end
end

-- Add the extracted variables to the document's metadata.
function Meta (meta)
  for name, value in pairs(variables) do
    meta[name] = value
  end
  return meta
end
```

Citations
=========

Emacs org-mode lacks an official citation syntax, leading to
multiple syntaxes coexisting. Pandoc recognizes four different
syntaxes for citations.

Citation support for org-mode is enabled by default. Support can
be toggled off by disabling the `citation` extension; e.g.
`pandoc --from=org-citations`.

Berkeley-style citations
------------------------

The semi-official Org-mode citation syntax was designed by Richard
Lawrence with additions by contributors on the [emacs-orgmode
mailing list]. It is based on John MacFarlane's pandoc Markdown
syntax. It's dubbed Berkeley syntax due the place of activity of
its creators, both philosophers at UC Berkeley.

### Simple in-text citation

This is the simplest form of citation. It consists of the citation
ID prefixed by '@'.

Example:

    @WatsonCrick1953 showed that DNA forms a double-helix.

### In-text citation list

Citations presented in the text unparenthesized are called
*in-text citations*. The syntax for these citations is

    [cite: PREFIX; INDIVIDUAL-REFERENCE; ... INDIVIDUAL-REFERENCE; SUFFIX]

where the initial PREFIX and final SUFFIX are optional. At least
one INDIVIDUAL-REFERENCE must be present. The colon and
semicolons here are literal and indicate the end of the TAG and
the end of a PREFIX or INDIVIDUAL-REFERENCE respectively.

An INDIVIDUAL-REFERENCE has the format:

    PREFIX KEY SUFFIX

The KEY is obligatory, and the prefix and suffix are optional.

A PREFIX or SUFFIX is arbitrary text (except `;`, `]`, and
citation keys).

Example:

    [cite: See; @Mandelkern1981; and @Watson1953]

### Parenthetical citation

Citations surrounded by parentheses. The syntax is identical to
in-text citations, except for the additional parentheses enclosing
the initial `cite` tag.

    [(cite): See; @Mandelkern1981; and @Watson1953]

[emacs-orgmode mailing list]: https://lists.gnu.org/archive/html/emacs-orgmode/2015-02/msg00932.html

org-ref citations
-----------------

The [org-ref] package by [John Kitchen] is in wide use to handle
citations and has excellent tooling support in Emacs. Its
citation syntax is geared towards users in the natural sciences
but still very flexible regardless.

    cite:doe_john_2000
    citep:doe_jane_1989
    [[citep:Dominik201408][See page 20 of::, for example]]


Pandoc-Markdown-like syntax
---------------------------

Historically, Markdown-style citations syntax was the first that
was added to pandoc's org reader. It is close to Markdown's
citation syntax.

Citations go inside square brackets and are separated by
semicolons. Each citation must have a key, composed of '@' plus
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:

### Simple citation

The simplest method to insert a citation is to write the citation
ID prefixed by '@'.


Example:

    [prefix @citekey suffix]
    [see @doe2000 pp. 23-42]
    [@doe2000 p. 5; to a lesser extend @doe2005]


LaTeX-Syntax
------------

Use normal latex citation commands like `\cite{x}` or
`\citet{y}`.

[org-ref]: https://github.com/jkitchin/org-ref
[John Kitchen]: https://kitchingroup.cheme.cmu.edu/

Tables
======

Pandoc supports normal org tables (sometimes called "pipe tables")
and grid tables (tables created by [table.el]).

Column widths
-------------

Org mode tables don't allow line-breaks within cells, and lines
which contain text can get very long. This often leads to tables
which run off the page when exporting, especially when exporting
to PDF via LaTeX. Overlong lines in the source text are this is
usually hidden by setting a [column width], but the default Emacs
exporters ignore that setting. Pandoc deviates from Emacs's
behavior and uses this information to resize the table columns
when exporting.

Limitations
-----------

There is no support yet for cells spanning multiple columns or
rows. The table.el grid tables allows rowspans and colspans and so
does pandoc's internal structure since 2.10, but the parser has
not been updated yet.

[table.el]: http://table.sourceforge.net/
[column width]: https://orgmode.org/manual/Column-Width-and-Alignment.html

Emphasis rules
==============

Org-mode uses complex rules to decide whether a string
represents emphasized text. In Emacs, this can be customized via
the variable `org-emphasis-regexp-components`. A variable like
this doesn't fit well with pandoc's model. Instead, it is
possible to use special lines to change these values:

    #+pandoc-emphasis-pre: "-\t ('\"{"
    #+pandoc-emphasis-post: "-\t\n .,:!?;'\")}["

The above describes the default values of these variables. The
arguments must be valid (Haskell) strings. If interpretation of
the argument as string fails, the default is restored.

Changing emphasis rules only affect the part of the document
following the special lines. They must be some of the first
lines to alter parsing behavior for the whole document. It is
also possible to change the values temporarily for selected
sections only. The string `test` in the following snippet will
be read as emphasized text, while the rest of the document will
be parsed using default emphasis rules:

    #+pandoc-emphasis-pre: "["
    #+pandoc-emphasis-post: "]"
    [/test/]
    #+pandoc-emphasis-pre:
    #+pandoc-emphasis-post:

`smart` extension
=================

Org-mode allows to insert certain characters via special character
sequences. For example, instead of typing the Unicode /HORIZONTAL
ELLISPIS/ character `…` by hand, one can instead type tree dots
`...`. En dashes and em dashes can be written as `--` and `---`
respectively. Furthermore, quotation marks (`"`) and
apostrophe-quotes (`'`) can be treated in a "smart" way,
potentially replacing them with proper, language specific unicode
quotation characters.

Like in Markdown, these behaviors can be turned on all-at-once by
enabling the `smart` extension. However, disabling `smart` (the
default) will *not* necessarily disable smart quotes and special
strings. Instead, it will just result in the default Org mode
behavior.

The special string feature can be turned off via the `#+OPTIONS:
-:nil` [export setting]. There are currently no command line flags
which control these features. As a workaround, one can use process
substitution, a feature supported by most shells. It allows to
provide the options line on the command line:

    pandoc -f org <(printf "#+OPTIONS: -:nil\n") …

[export setting]: https://orgmode.org/manual/Export-Settings.html

Currently unsupported features
==============================

Library of babel
----------------

The library of babel translates between various programming
languages. This is out-of-scope for pandoc. Use Emacs to run
code, then feed the resulting org file to pandoc.