Markdown

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Markdown
Filename extension .md, .markdown[1]
Uniform Type Identifier (UTI) net.daringfireball.markdown
Developed by John Gruber
Initial release March 25, 2004; 10 years ago (2004-03-25)[2]
Latest release 1.0.1  / December 17, 2004; 9 years ago (2004-12-17)[3]
Type of format Markup language
Open format? yes[4]
Website daringfireball.net/projects/markdown/

Markdown is a plain text formatting syntax[5] designed so that it optionally can be converted to HTML using a tool by the same name. Markdown is popularly used to format readme files, for writing messages in online discussion forums or in text editors for the quick creation of rich text documents.

History[edit]

The Markdown language was created in 2004 by John Gruber with substantial contributions from Aaron Swartz,[6] with the goal of allowing people “to write using an easy-to-read, easy-to-write plain text format, and optionally convert it to structurally valid XHTML (or HTML)”.[3]

Taking cues from existing conventions for marking up plain text in email such as setext, the language was designed to be readable as-is, without looking like it's been marked up with tags or formatting instructions,[7] unlike text formatted with a Markup language, such as HTML, which has obvious tags and formatting instructions. Markdown is a formatting syntax for text that can be read by humans and can be easily converted to HTML.

Gruber wrote a Perl script, Markdown.pl, which converts marked-up text input to valid, well-formed XHTML or HTML and replaces left-pointing angle brackets ('<') and ampersands with their corresponding character entity references. It can be used as a standalone script, as a plugin for Blosxom or Movable Type, or as a text filter for BBEdit.[3]

Markdown has since been re-implemented by others as a Perl module available on CPAN (Text::Markdown), and in a variety of other programming languages. It is distributed under a BSD-style license[4] and is included with, or available as a plugin for, several content-management systems.[8][9]

Sites such as GitHub, reddit, Diaspora, Stack Exchange, OpenStreetMap, and SourceForge use variants of Markdown to facilitate discussion between users.[10][11][12][13]

Standardization[edit]

There is no clearly defined Markdown standard, apart from the original writeup and implementation by John Gruber, which some consider to be abandonware.[14][15] This has led to fragmentation as different vendors write their own variants of the language to correct flaws or add missing features.

From 2012 through 2014, a group of people including Jeff Atwood launched what Atwood characterized as a standardization effort.[16] A community website now aims to "document various tools and resources available to document authors and developers, as well as implementors of the various markdown implementations".[17] In September 2014, Gruber objected to the usage of "Markdown" in the name of this effort and it was rebranded as a new dialect named "CommonMark".[18][19]

A tool (named Babelmark2[20]) is also available to "[compare] the output of various implementations" to "promote discussion of how and whether certain vague aspects of the markdown spec should be clarified".[21] Gruber has argued that complete standardisation would be mistaken: "Different sites (and people) have different needs. No one syntax would make all happy."[22]

A standards effort for the Internet media type text/markdown (independent of the syntax) is underway in the IETF. The Internet-Draft, draft-ietf-appsawg-text-markdown, is planned to be submitted to the IESG in April 2015. The Markdown community is invited to submit use cases for Markdown, which will inform the media type standardization process.

Extensions[edit]

A number of lightweight markup languages extend Markdown by implementing added features (such as tables, footnotes, definition lists, and Markdown inside HTML blocks) not available with plain Markdown syntax. Among these are Markdown Extra, MultiMarkdown, Maruku,[23] Kramdown and the Pandoc Markdown extension.[24] In some cases, this is in order to enable conversion into more formats than HTML, e.g. LaTeX, RTF and DocBook.

Many implementations also intentionally omit support for middle word emphasis. The original Markdown implementation interprets constructs like my_long_variable as a request to emphasize "long" in the middle of a word. Many users found this confusing, so many later implementations such as PHP Markdown and Python Markdown do not implement middle word emphasis by default.[25]

The essay "Thoughts on Markdown" stated that Markdown's original developer, John Gruber, has not responded to discussions about extensions to Markdown, and that "Markdown is changing, with or without him".

Example[edit]

text using Markdown syntax the corresponding HTML produced by a Markdown processor the text viewed in a browser
 Heading
 =======
 
 Sub-heading
 -----------
 
 h3. Traditional html title
 
 Paragraphs are separated
 by a blank line.
 
 Let 2 spaces at the end of a line to do a  
 line break
 
 Text attributes *italic*,
 **bold**, `monospace`.
 
 A [link](http://example.com).
 <<<   No space between ] and (  >>>
 
 Shopping list:
 
   * apples
   * oranges
   * pears
 
 Numbered list:
 
   1. apples
   2. oranges
   3. pears
 
 The rain---not the reign---in
 Spain.
<h1>Heading</h1>
 
<h2>Sub-heading</h2>
 
<h3>Traditional html title</h3>
 
<p>Paragraphs are separated
by a blank line.</p>
 
<p>Let 2 spaces at the end of a line to do a<br />
line break</p>
 
<p>Text attributes <em>italic</em>,
<strong>bold</strong>,
<code>monospace</code>.</p>
 
<p>A <a href="http://example.com">link</a>.</p>
 
<p>Shopping list:</p>
 
<ul>
<li>apples</li>
<li>oranges</li>
<li>pears</li>
</ul>
 
<p>Numbered list:</p>
 
<ol>
<li>apples</li>
<li>oranges</li>
<li>pears</li>
</ol>
 
<p>The rain&mdash;not the
reign&mdash;in Spain.</p>
Heading
Sub-heading
Traditional html title

Paragraphs are separated by a blank line.

Let 2 spaces at the end of a line to do a
line break

Text attributes italic, bold, monospace.

A link.

Shopping list:

  • apples
  • oranges
  • pears

Numbered list:

  1. apples
  2. oranges
  3. pears

The rain—not the reign—in Spain.

Editors[edit]

While Markdown is a minimal markup language and is easily read and edited with a normal text editor, there are specially-designed editors that preview the files with styles. There are a variety of such editors available for all major platforms; one such graphical editor for Windows is MarkdownPad. There are syntax highlighting plugins for Markdown built into emacs, gedit, and vim.

Implementations[edit]

Implementations of Markdown are available for many different frameworks, platforms and languages.

Test Suites[edit]

There are many more open-source implementations of Markdown available online.

See also[edit]

References[edit]

  1. ^ Daring Fireball Statement by creator John Gruber
  2. ^ "Daring Fireball: Markdown". Web.archive.org. Retrieved 2014-04-25. 
  3. ^ a b c Markdown 1.0.1 readme source code "Daring Fireball – Markdown". 17 Dec 2004. 
  4. ^ a b "Markdown: License". Daring Fireball. Retrieved 2014-04-25. 
  5. ^ "Markdown". December 4, 2013. 
  6. ^ "Markdown". Aaron Swartz: The Weblog. March 19, 2004. 
  7. ^ Markdown Syntax "Daring Fireball – Markdown – Syntax". 13 Jun 2013. 
  8. ^ "MarsEdit 2.3 ties the knot with Tumblr support – Ars Technica". Retrieved 2009-08-11. 
  9. ^ "Review: Practical Django Projects – Ars Technica". Retrieved 2009-08-11. 
  10. ^ a b "GitHub Flavored Markdown". github.com. Retrieved 29 March 2013. 
  11. ^ "Reddit markdown primer. Or, how do you do all that fancy formatting in your comments, anyway?". reddit.com. Retrieved 29 March 2013. 
  12. ^ "Markdown Editing Help". http://stackoverflow.com. Retrieved 11 April 2014. 
  13. ^ "SourceForge: Markdown Syntax Guide". sourceforge.net. Retrieved 2013-05-10. 
  14. ^ Atwood, Jeff. "Responsible Open Source Code Parenting". Codinghorror.com. Retrieved 2014-04-25. 
  15. ^ "Trouble with parentheses in Markdown hyperlinks". Six.pairlist.net. 2012-10-17. Retrieved 2014-04-25. 
  16. ^ a b Atwood, Jeff (2012-10-25). "The Future of Markdown". Codinghorror.com. Retrieved 2014-04-25. 
  17. ^ "Markdown Community Page". Markdown.github.io. Retrieved 2014-04-25. 
  18. ^ http://blog.codinghorror.com/standard-markdown-is-now-common-markdown/
  19. ^ http://www.infoq.com/news/2014/09/markdown-commonmark
  20. ^ "Babelmark 2 - Compare markdown implementations". Johnmacfarlane.net. Retrieved 2014-04-25. 
  21. ^ "Babelmark 2 - FAQ". Johnmacfarlane.net. Retrieved 2014-04-25. 
  22. ^ Gruber, John. "Twitter post". Retrieved 6 September 2014. 
  23. ^ Maruku
  24. ^ Pandoc Markdown
  25. ^ Markdown Discuss
  26. ^ "Doxygen Manual: Markdown support". Stack.nl. 2014-04-21. Retrieved 2014-04-25. 
  27. ^ file 462 lines (396 sloc) 12.572 kb. "rstudio/src/cpp/core/markdown/Markdown.cpp at master · rstudio/rstudio · GitHub". Github.com. Retrieved 2014-04-25. 
  28. ^ "JetBrains Plugin Repository :: Markdown". Plugins.jetbrains.com. Retrieved 2014-04-25. 
  29. ^ "nicoulaj/idea-markdown ¡ GitHub". Github.com. 2013-12-01. Retrieved 2014-04-25. 
  30. ^ "Writing on GitHub". help.github.com. Github, Inc. Retrieved 9 July 2014. 
  31. ^ "Pandoc's markdown". Retrieved 2014-08-05. 

External links[edit]