Lightweight markup language

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Short description: Markup language with simple, unobtrusive syntax

A lightweight markup language (LML), also termed a simple or humane markup language, is a markup language with simple, unobtrusive syntax. It is designed to be easy to write using any generic text editor and easy to read in its raw form. Lightweight markup languages are used in applications where it may be necessary to read the raw document as well as the final rendered output.

For instance, a person downloading a software library might prefer to read the documentation in a text editor rather than a web browser. Another application for such languages is to provide for data entry in web-based publishing, such as blogs and wikis, where the input interface is a simple text box. The server software then converts the input into a common document markup language like HTML.

History

Lightweight markup languages were originally used on text-only displays which could not display characters in italics or bold, so informal methods to convey this information had to be developed. This formatting choice was naturally carried forth to plain-text email communications. Console browsers may also resort to similar display conventions.

In 1986 international standard SGML provided facilities to define and parse lightweight markup languages using grammars and tag implication. The 1998 W3C XML is a profile of SGML that omits these facilities. However, no SGML document type definition (DTD) for any of the languages listed below is known.

Types

Lightweight markup languages can be categorized by their tag types. Like HTML (<b>bold</b>), some languages use named elements that share a common format for start and end tags (e.g. BBCode [b]bold[/b]), whereas proper lightweight markup languages are restricted to ASCII-only punctuation marks and other non-letter symbols for tags, but some also mix both styles (e.g. Textile bq. ) or allow embedded HTML (e.g. Markdown), possibly extended with custom elements (e.g. MediaWiki <ref>'''source'''</ref>).

Most languages distinguish between markup for lines or blocks and for shorter spans of texts, but some only support inline markup.

Some markup languages are tailored for a specific purpose, such as documenting computer code (e.g. POD, reST, RD) or being converted to a certain output format (usually HTML or LaTeX) and nothing else, others are more general in application. This includes whether they are oriented on textual presentation or on data serialization.[clarification needed]

Presentation oriented languages include AsciiDoc, atx, BBCode, Creole, Crossmark, Djot, Epytext, Haml, JsonML, MakeDoc, Markdown, Org-mode, POD (Perl), reST (Python), RD (Ruby), Setext, SiSU, SPIP, Xupl, Texy!, Textile, txt2tags, UDO and Wikitext.

Data serialization oriented languages include Curl (homoiconic, but also reads JSON; every object serializes), JSON, and YAML.

Comparison of language features

Comparing language features
Language HTML export tool HTML import tool Tables Link titles class attribute id attribute Release date
AsciiDoc Yes Yes Yes Yes Yes Yes 2002-11-25[1]
BBCode No No Yes No No No 1998
Creole No No Yes No No No 2007-07-04[2]
Djot Yes Yes[3] Yes Yes Yes Yes 2022-07-30[4]
Gemtext Yes ? No Yes No No 2020
GitHub Flavored Markdown Yes No Yes Yes No No 2011-04-28+
Jira Formatting Notation Yes No Yes Yes No No 2002+[5]
Markdown Yes Yes No Yes Yes/No Yes/No 2004-03-19[6][7]
Markdown Extra Yes Yes Yes[8] Yes Yes Yes 2013-04-11[9]
MediaWiki Yes Yes Yes Yes Yes Yes 2002[10]
MultiMarkdown Yes No Yes Yes No No 2009-07-13
Org-mode Yes Yes[11] Yes Yes Yes Yes 2003[12]
PmWiki Yes[13] Yes Yes Yes Yes Yes 2002-01
POD Yes ? No Yes ? ? 1994
reStructuredText Yes Yes[11] Yes Yes Yes auto 2002-04-02[14]
setext Yes Yes No Yes No No 1992[15]
Slack No No No Yes No No 2013+[16][17]
TiddlyWiki Yes No Yes Yes Yes No 2004-09[18]
Textile Yes No Yes Yes Yes Yes 2002-12-26[19]
Texy Yes Yes Yes Yes Yes Yes 2004[20]
txt2tags Yes Yes[21] Yes[22] Yes Yes/No Yes/No 2001-07-26[23]
WhatsApp No No No No No No 2016-03-16[24]

Markdown's own syntax does not support class attributes or id attributes; however, since Markdown supports the inclusion of native HTML code, these features can be implemented using direct HTML. (Some extensions may support these features.)

txt2tags' own syntax does not support class attributes or id attributes; however, since txt2tags supports inclusion of native HTML code in tagged areas, these features can be implemented using direct HTML when saving to an HTML target.[25]

Comparison of implementation features

Comparing implementations, especially output formats
Language Implementations XHTML Con/LaTeX PDF DocBook ODF EPUB DOC(X) LMLs Other License
AsciiDoc Python, Ruby, JavaScript, Java XHTML LaTeX PDF DocBook ODF EPUB No N/A Man page etc. GNU GPL, MIT
BBCode Perl, PHP, C#, Python, Ruby (X)HTML No No No No No No N/A N/A Public Domain
Creole PHP, Python, Ruby, JavaScript[26] Depends on implementation CC BY-SA 1.0
Djot Lua (originally), JavaScript, Prolog, Rust[3] HTML LaTeX, ConTeXt PDF DocBook ODF EPUB RTF MediaWiki, reST Man page, S5 etc. MIT
GitHub Flavored Markdown Haskell (Pandoc) HTML LaTeX, ConTeXt PDF DocBook ODF EPUB DOC AsciiDoc, reST OPML GPL
Java,[27] JavaScript,[28][29][30] PHP,[31][32] Python,[33] Ruby[34] HTML[28][29][30][32][33] No No No No No No N/A N/A Proprietary
Markdown Perl (originally), C,[35][36] Python,[37] JavaScript, Haskell,[11] Ruby,[38] C#, Java, PHP HTML LaTeX, ConTeXt PDF DocBook ODF EPUB RTF MediaWiki, reST Man page, S5 etc. BSD-style & GPL (both)
Markdown Extra PHP (originally), Python, Ruby XHTML No No No No No No N/A N/A BSD-style & GPL (both)
MediaWiki Perl, PHP, Haskell, Python XHTML No No No No No No N/A N/A GNU GPL
MultiMarkdown C, Perl (X)HTML LaTeX PDF No ODF No DOC, RTF N/A OPML GPL, MIT
Org-mode Emacs Lisp, Ruby (parser only), Perl, OCaml XHTML LaTeX PDF DocBook ODF EPUB[39] DOCX[39] Markdown TXT, XOXO, iCalendar, Texinfo, man, contrib: groff, s5, deck.js, Confluence Wiki Markup,[40] TaskJuggler, RSS, FreeMind GPL
PmWiki PHP XHTML 1.0 Transitional, HTML5 No PDF export addons No No EPUB export addon No N/A N/A GNU GPL
POD Perl (X)HTML, XML LaTeX PDF DocBook No No RTF N/A Man page, plain text Artistic License, Perl's license
reStructuredText Python,[41][42] Haskell (Pandoc), Java, HTML, XML LaTeX PDF DocBook ODF EPUB DOC N/A man, S5, Devhelp, QT Help, CHM, JSON Public Domain
Textile PHP, JavaScript, Java, Perl, Python, Ruby, ASP, C#, Haskell XHTML No No No No No No N/A N/A Textile License
Texy! PHP, C# (X)HTML No No No No No No N/A N/A GNU GPL v2 License
txt2tags Python,[43] PHP[44] (X)HTML, SGML LaTeX PDF DocBook ODF EPUB DOC Creole, AsciiDoc, MediaWiki, MoinMoin, PmWiki, DokuWiki, Google Code Wiki roff, man, MagicPoint, Lout, PageMaker, ASCII Art, TXT GPL

Comparison of lightweight markup language syntax

Inline span syntax

Although usually documented as yielding italic and bold text, most lightweight markup processors output semantic HTML elements em and strong instead. Monospaced text may either result in semantic code or presentational tt elements. Few languages make a distinction, e.g. Textile, or allow the user to configure the output easily, e.g. Texy.

LMLs sometimes differ for multi-word markup where some require the markup characters to replace the inter-word spaces (infix). Some languages require a single character as prefix and suffix, other need doubled or even tripled ones or support both with slightly different meaning, e.g. different levels of emphasis.

Comparison of text formatting syntax
HTML output <strong>strongly emphasized</strong> <em>emphasized text</em> <code>code</code> semantic
<b>bold text</b> <i>italic text</i> <tt>monospace text</tt> presentational
AsciiDoc *bold text* 'italic text' +monospace text+ Can double operators to apply formatting where there is no word boundary (for example **b**old t**ex**t yields bold text).
_italic text_ `monospace text`
BBCode [b]bold text[/b] [i]italic text[/i] [code]monospace text[/code] Formatting works across line breaks.
Creole **bold text** //italic text// {{{monospace text}}} Triple curly braces are for nowiki which is optionally monospace.
Djot *bold text* _italic text_ `monospace text`
Gemtext N/A N/A ```alt text
monospace text
```
Text immediately following the first three backticks is alt-text.
Jira Formatting Notation *bold text* _italic text_ {{monospace text}}
Markdown[45] **bold text** *italic text* `monospace text` semantic HTML tags
__bold text__ _italic text_
MediaWiki '''bold text''' ''italic text'' <code>monospace text</code> mostly resorts to inline HTML
Org-mode *bold text* /italic text/ =code=
~verbatim~
PmWiki '''bold text''' ''italic text'' @@monospace text@@
reST **bold text** *italic text* ``monospace text``
Setext **bold text** ~italic text~ `monospace text`
Textile[46] *strong* _emphasis_ @monospace text@ semantic HTML tags
**bold text** __italic text__ presentational HTML tags
Texy! **bold text** *italic text* `monospace text` semantic HTML tags by default, optional support for presentational tags
//italic text//
TiddlyWiki ''bold text'' //italic text// `monospace text`
``monospace text``
txt2tags **bold text** //italic text// ``monospace text``
POD B<bold text> I<italic text> C<monospace text> Indented text is also shown as monospaced code.
Slack *bold text* _italic text_ `monospace text` ```block of monospaced text```
WhatsApp *bold text* _italic text_ ```monospace text```

Gemtext does not have any inline formatting, monospaced text (called preformatted text in the context of Gemtext) must have the opening and closing ``` on their own lines.

Emphasis syntax

In HTML, text is emphasized with the <em> and <strong> element types, whereas <i> and <b> traditionally mark up text to be italicized or bold-faced, respectively.

Microsoft Word and Outlook, and accordingly other word processors and mail clients that strive for a similar user experience, support the basic convention of using asterisks for boldface and underscores for italic style. While Word removes the characters, Outlook retains them.

Italic type or normal emphasis
Code AsciiDoc ATX Creole Jira Markdown MediaWiki Org-mode PmWiki reST Setext Slack Textile Texy! TiddlyWiki txt2tags WhatsApp
*italic* No No No No Yes No No No Yes No No No Yes No No No
**italic** No No No No No No No No No No No No No No No No
_italic_ Yes Yes No Yes Yes No No No No No Yes Yes No No No Yes
__italic__ Yes No No No No No No No No No No Yes No No No No
'italic' Yes No No No No No No No No No No No No No No No
''italic'' Yes No No No No Yes No Yes No No No No No No No No
/italic/ No No No No No No Yes No No No No No No No No No
//italic// No No Yes No No No No No No No No No Yes Yes Yes No
~italic~ No No No No No No No No No Yes No No No No No No
Bold face or strong emphasis
Code AsciiDoc ATX Creole Jira Markdown MediaWiki Org-mode PmWiki reST Setext Slack Textile Texy! TiddlyWiki txt2tags WhatsApp
*bold* Yes Yes No Yes No No Yes No No No Yes Yes No No No Yes
**bold** Yes No Yes No Yes No No No Yes Yes No Yes Yes No Yes No
__bold__ No No No No Yes No No No No No No No No No No No
''bold'' No No No No No No No No No No No No No Yes No No
'''bold''' No No No No No Yes No Yes No No No No No No No No

Editorial syntax

In HTML, removed or deleted and inserted text is marked up with the <del> and <ins> element types, respectively. However, legacy element types <s> or <strike> and <u> are still also available for stricken and underlined spans of text.

Underlined or inserted text
Code Jira Markdown Org-mode Setext TiddlyWiki txt2tags
_underline_ No Optional Yes Yes No No
__underline__ No Optional No No Yes Yes
+underline+ Yes No No No No No

AsciiDoc, ATX, Creole, MediaWiki, PmWiki, reST, Slack, Textile, Texy! and WhatsApp do not support dedicated markup for underlining text. Textile does, however, support insertion via the +inserted+ syntax.

Strike-through or deleted text
Code Jira Markdown Org-mode Slack Textile TiddlyWiki txt2tags WhatsApp
~stricken~ No No No Yes No No No Yes
~~stricken~~ No GFM No No No Yes No No
+stricken+ No No Yes No No No No No
-stricken- Yes No No No Yes No No No
--stricken-- No No No No No No Yes No

AsciiDoc, ATX, Creole, MediaWiki, PmWiki, reST, Setext and Texy! do not support dedicated markup for striking through text.

Programming syntax

Quoted computer code is traditionally presented in typewriter-like fonts where each character occupies the same fixed width. HTML offers the semantic <code> and the deprecated, presentational <tt> element types for this task.

Monospaced font, teletype text or code
Code AsciiDoc ATX Creole Gemtext Jira Markdown Org-mode PmWiki reST Slack Textile Texy! TiddlyWiki txt2tags WhatsApp
@code@ No No No No No No No No No No Yes No No No No
@@code@@ No No No No No No No Yes No No No No No No No
`code` Yes No No No No Yes No No No Yes No Yes Yes No No
``code`` Yes No No No No Yes No No Yes No No No Yes Yes No
```code``` No No No Yes No Yes No No No Yes/No No No Yes No Yes
=code= No No No No No No Yes No No No No No No No No
~code~ No No No No No No Yes No No No No No No No No
+code+ Yes No No No No No No No No No No No No No No
++code++ Yes No No No No No No No No No No No No No No
{{code}} No No No No Yes No No No No No No No No No No
{{{code}}} No No Yes No No No No No No No No No No No No
|code| No Yes No No No No No No No No No No No No No
;;code;;

Mediawiki and Gemtext do not provide lightweight markup for inline code spans.

Heading syntax

Headings are usually available in up to six levels, but the top one is often reserved to contain the same as the document title, which may be set externally. Some documentation may associate levels with divisional types, e.g. part, chapter, section, article or paragraph.

Most LMLs follow one of two styles for headings, either Setext-like underlines or atx-like[47] line markers, or they support both.

Underlined headings

Level 1 Heading
===============

Level 2 Heading
---------------

Level 3 Heading
~~~~~~~~~~~~~~~

The first style uses underlines, i.e. repeated characters (e.g. equals =, hyphen - or tilde ~, usually at least two or four times) in the line below the heading text.

Underlined heading levels
Chars: = - ~ * # + ^ _ : " ' ` . min length
Markdown 1 2 No No No No No No No No No No No 1
Setext 1 2 No No No No No No No No No No No ?
AsciiDoc 1 2 3 No No No No No No No No No No 2
Texy! 3 4 No 2 1 No No No No No No No No 3
reStructuredText Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes heading width

RST determines heading levels dynamically, which makes authoring more individual on the one hand, but complicates merges from external sources on the other hand.

Prefixed headings

# Level 1 Heading
## Level 2 Heading ##
### Level 3 Heading ###

The second style is based on repeated markers (e.g. hash #, equals = or asterisk *) at the start of the heading itself, where the number of repetitions indicates the (sometimes inverse) heading level. Most languages also support the reduplication of the markers at the end of the line, but whereas some make them mandatory, others do not even expect their numbers to match.

Line prefix (and suffix) headings
Character: = # * ! + Suffix Levels Indentation
AsciiDoc Yes No No No No Optional 1–6 No
Creole Yes No No No No Optional 1–6 No
Gemtext No Yes No No No ? 1–3 No
MediaWiki Yes No No No No Yes 1–6 No
TiddlyWiki No No No Yes No No 1–6 No
txt2tags Yes No No No Yes Yes 1–6 No
Markdown No Yes No No No Optional 1–6 No
Texy! Yes Yes No No No Optional 6–1 or 1–6, dynamic No
Org-mode No No Yes No No No 1– +∞ alternative[48][49][50]
PmWiki No No No Yes No Optional 1–6 No

Org-mode supports indentation as a means of indicating the level.

BBCode does not support section headings at all.

POD and Textile choose the HTML convention of numbered heading levels instead.

Other heading formats
Language Format
POD
=head1 Level 1 Heading
=head2 Level 2 Heading
Textile,[46] Jira[5]
h1. Level 1 Heading
h2. Level 2 Heading
h3. Level 3 Heading
h4. Level 4 Heading
h5. Level 5 Heading
h6. Level 6 Heading

Microsoft Word supports auto-formatting paragraphs as headings if they do not contain more than a handful of words, no period at the end and the user hits the enter key twice. For lower levels, the user may press the tabulator key the according number of times before entering the text, i.e. one through eight tabs for heading levels two through nine.

Link syntax

Hyperlinks can either be added inline, which may clutter the code because of long URLs, or with named alias or numbered id references to lines containing nothing but the address and related attributes and often may be located anywhere in the document. Most languages allow the author to specify text Text to be displayed instead of the plain address http://example.com and some also provide methods to set a different link title Title which may contain more information about the destination.

LMLs that are tailored for special setups, e.g. wikis or code documentation, may automatically generate named anchors (for headings, functions etc.) inside the document, link to related pages (possibly in a different namespace) or provide a textual search for linked keywords.

Most languages employ (double) square or angular brackets to surround links, but hardly any two languages are completely compatible. Many can automatically recognize and parse absolute URLs inside the text without further markup.

Hyperlink syntax
Languages Basic syntax Text syntax Title syntax
BBCode, Creole, MediaWiki, PmWiki http://example.com
Textile "Text":http://example.com "Text (Title)":http://example.com
Texy! "Text .(Title)":http://example.com
AsciiDoc http://example.com[Text]
Slack <http://example.com|Text>
TiddlyWiki http://example.com
Jira [http://example.com] [Text|http://example.com]
txt2tags [Text http://example.com]
MediaWiki [http://example.com Text]
Creole, MediaWiki, PmWiki [[Philosophy:Name|Name]] [[Philosophy:Name|Text]]
Org-mode Name][Text
TiddlyWiki Name
Creole Namespace:Name Text
Org-mode Namespace:Name][Text
Creole, PmWiki http://example.com Text
BBCode [url]http://example.com[/url] [url=http://example.com]Text[/url]
Markdown <http://example.com> [Text](http://example.com) [Text](http://example.com "Title")
reStructuredText `Text <http://example.com/>`_
setext ^.. _Link_name URL
POD L<http://example.com/> L</Name>
Gemtext => gemini://example.com => gemini://example.com Text

Gemtext and setext links must be on a line by themselves, they cannot be used inline.

Reference syntax
Languages Text syntax Title syntax
AsciiDoc
… id …
<<id>>
… id …
<<id,Text>>
… anchor:id …
xref:id
… anchor:id …
xref:id[Text]
Markdown
… [Text][id] …
[id]: http://example.com
… [Text][id] …
[id]: http://example.com "Title"
… [Text][] …
[Text]: http://example.com
… [Text][] …
[Text]: http://example.com "Title"
… [Text] …
[Text]: http://example.com
… [Text] …
[Text]: http://example.com "Title"
reStructuredText
… Name_ …
.. _Name: http://example.com
setext
… Link_name_ …
^.. _Link_name URL
Textile
… "Text":alias …
[alias]http://example.com
… "Text":alias …
[alias (Title)]http://example.com
Texy!
… "Text":alias …
[alias]: http://example.com
… "Text":alias …
[alias]: http://example.com .(Title)

Org-mode's normal link syntax does a text search of the file. You can also put in dedicated targets with <<id>>.

List syntax

HTML requires an explicit element for the list, specifying its type, and one for each list item, but most lightweight markup languages need only different line prefixes for the bullet points or enumerated items. Some languages rely on indentation for nested lists, others use repeated parent list markers.

Unordered, bullet list items
Characters: * - + # . · _ : indent skip nest
Markdown Yes Yes Yes No No No No No No No No 0–3 1–3 indent
MediaWiki, TiddlyWiki Yes No No No No No No No No No No 0 1+ repeat
Org-mode Yes[51] Yes Yes No No No No No No No No 0+ indent
Jira Yes Yes No No No No No No No No No 0 1+ repeat
Gemtext Yes No No No No No No No No No No 0 1+ No
Textile Yes No No No No No No No No No No 0 1+ repeat

Microsoft Word automatically converts paragraphs that start with an asterisk *, hyphen-minus - or greater-than bracket > followed by a space or horizontal tabulator as bullet list items. It will also start an enumerated list for the digit 1 and the case-insensitive letters a (for alphabetic lists) or i (for roman numerals), if they are followed by a period ., a closing round parenthesis ), a greater-than sign > or a hyphen-minus - and a space or tab; in case of the round parenthesis an optional opening one ( before the list marker is also supported.

Languages differ on whether they support optional or mandatory digits in numbered list items, which kinds of enumerators they understand (e.g. decimal digit 1, roman numerals i or I, alphabetic letters a or A) and whether they support to keep explicit values in the output format. Some Markdown dialects, for instance, will respect a start value other than 1, but ignore any other explicit value.

Ordered, enumerated list items
Chars: + # #1 1. 1) 1] 1} (1) [1] {1} a. A. i. I. indent skip nest
Markdown No No No Yes Yes No No No No No No No No No 0–3 1–3 indent
MediaWiki, TiddlyWiki No Yes No No No No No No No No No No No No 0 1+ repeat
Org-mode No No No Yes Yes No No No No No Optional No No 0+ indent
Jira, Textile No Yes No No No No No No No No No No No No 0 1+ repeat

Slack assists the user in entering enumerated and bullet lists, but does not actually format them as such, i.e. it just includes a leading digit followed by a period and a space or a bullet character in front of a line.

Labeled, glossary, definition list syntax
Languages Term being defined Definition of the term
MediaWiki ; Term : Definition
Textile
TiddlyWiki
Org-mode - Term :: Definition

Historical formats

The following lightweight markup languages, while similar to some of those already mentioned, have not yet been added to the comparison tables in this article:

  • EtText:[52] circa 2000
  • Grutatext:[52] circa 2002

See also

References

  1. "AsciiDoc ChangeLog". http://asciidoc.org/CHANGELOG.html. 
  2. "WikiCreole Versions". http://www.wikicreole.org/wiki/Versions. 
  3. 3.0 3.1 "djot". https://djot.net/. 
  4. "djot 0.1.0". https://github.com/jgm/djot/releases/tag/0.1.0. 
  5. 5.0 5.1 "Text Formatting Notation Help". Atlassian. https://jira.atlassian.com/secure/WikiRendererHelpAction.jspa?section=all. 
  6. "Markdown". Aaron Swartz: The Weblog. 2004-03-19. http://www.aaronsw.com/weblog/001189. 
  7. "Daring Fireball: Markdown". http://daringfireball.net/projects/markdown/. 
  8. "PHP Markdown Extra". Michel Fortin. http://michelf.com/projects/php-markdown/extra/#table. 
  9. "PHP Markdown: History". Michel Fortin. https://michelf.ca/projects/php-markdown/version-history/. 
  10. "MediaWiki history". https://www.mediawiki.org/wiki/MediaWiki_history. 
  11. 11.0 11.1 11.2 Pandoc, which is written in Haskell, parses Markdown (in two forms) and ReStructuredText, as well as HTML and LaTeX; it writes from any of these formats to HTML, RTF, LaTeX, ConTeXt, OpenDocument, EPUB and several other formats, including (via LaTeX) PDF.
  12. "Org mode for Emacs – Your Life in Plain Text". OrgMode team. http://orgmode.org/. 
  13. "PmWiki Cookbook - Export addons". http://www.pmwiki.org/wiki/PmWiki/Cookbook?action=search&q=name%3DXmlExport%2CBackupHTMLZip%2CExportHTML*%2CPrintGroup+list%3Dmain. 
  14. "An Introduction to reStructuredText". http://docutils.sourceforge.net/docs/ref/rst/introduction.html#history. 
  15. "TidBITS in new format" (in en). 1992-01-06. https://tidbits.com/1992/01/06/tidbits-in-new-format/. 
  16. "Slack Help Center > Using Slack > Send messages > Format your messages". https://get.slack.help/hc/en-us/articles/202288908. 
  17. "Slack API documentation: Basic message formatting". https://api.slack.com/docs/message-formatting. 
  18. "History of TiddlyWiki". tiddlywiki.com. https://tiddlywiki.com/#History%20of%20TiddlyWiki. 
  19. "Textism › Tools › Textile". textism.com. http://textism.com/tools/textile/. 
  20. "What is Texy". https://texy.info/en/. 
  21. "Html2wiki txt2tags module". cpan.org. https://metacpan.org/pod/HTML::WikiConverter::Txt2tags. 
  22. "Txt2tags User Guide". Txt2tags.org. http://txt2tags.org/userguide/Table.html#6_14. 
  23. "txt2tags changelog". http://txt2tags.org/changelog.html. 
  24. "WhatsApp FAQ: Formatting your messages". https://faq.whatsapp.com/en/android/26000002/. 
  25. "Txt2tags User Guide". Txt2tags.org. http://txt2tags.org/userguide/TaggedTaggedLineTaggedArea.html#6_16. 
  26. "Converters". WikiCreole. http://www.wikicreole.org/wiki/Converters. 
  27. pegdown: A Java library for Markdown processing
  28. 28.0 28.1 gfms: Github Flavored Markdown Server
  29. 29.0 29.1 marked: A full-featured markdown parser and compiler, written in JavaScript. Built for speed.
  30. 30.0 30.1 node-gfm: GitHub flavored markdown to HTML converter
  31. Parsedown: Markdown parser written in PHP
  32. 32.0 32.1 Ciconia: Markdown parser written in PHP
  33. 33.0 33.1 Grip: GitHub Readme Instant Preview
  34. github-markdown: Self-contained Markdown parser for GitHub
  35. peg-markdown is an implementation of markdown in C.
  36. Discount is also an implementation of markdown in C.
  37. "Python-Markdown". Github.com. https://github.com/waylan/Python-Markdown. 
  38. Bruce Williams <http://codefluency.com>, for Ruby Central <http://rubycentral.org>. "kramdown: Project Info". RubyForge. https://rubyforge.org/projects/kramdown/. 
  39. 39.0 39.1 "Via ox-pandoc and pandoc itself". https://github.com/kawabata/ox-pandoc#description. 
  40. Atlassian. "Confluence 4.0 Editor - What's Changed for Wiki Markup Users (Confluence Wiki Markup is dead)". https://confluence.atlassian.com/display/CONF40/Confluence+4+Editor+-+What%27s+Changed+for+Wiki+Markup+Users. 
  41. Docutils is an implementation of ReStructuredText in Python
  42. Sphinx is an implementation of ReStructuredText in Python and Docutils with a number of output format Builders
  43. Aurelio Jargas www.aurelio.net (2012-01-11). "txt2tags". txt2tags. http://txt2tags.org/. 
  44. "txt2tags.class.php - online convertor [sic]". Txt2tags.org. http://txt2tags.org/txt2tags.form.php. 
  45. "Markdown Syntax". Daringfireball.net. http://daringfireball.net/projects/markdown/syntax. 
  46. 46.0 46.1 Textile Syntax
  47. "atx, the true structured text format" by Aaron Swartz (2002)
  48. "The Org Manual: section "A Cleaner Outline View"". https://orgmode.org/org.html#Clean-View. 
  49. "using org-adapt-indentation". http://lists.gnu.org/archive/html/emacs-orgmode/2009-07/msg00651.html. 
  50. "using org-indent-mode or org-indent". http://emacs.stackexchange.com/questions/3786/indented-multi-tiered-lists-and-headings-with-org-indent-mode. 
  51. Footnote in official manual "When using ‘*’ as a bullet, lines must be indented so that they are not interpreted as headlines. Also, when you are hiding leading stars to get a clean outline view, plain list items starting with a star may be hard to distinguish from true headlines. In short: even though ‘*’ is supported, it may be better to not use it for plain list items."
  52. 52.0 52.1 Cite error: Invalid <ref> tag; no text was provided for refs named {{{1}}}

External links

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