Python-Markdown — Python-Markdown 3.8 documentation (original) (raw)

This is a Python implementation of John Gruber’sMarkdown. It is almost completely compliant with the reference implementation, though there are a few very minor differences. See John’sSyntax Documentationfor the syntax rules.

To get started, see the installation instructions, the library reference, and the command line interface.

Goals¶

The Python-Markdown project is developed with the following goals in mind:

• Maintain a Python library (with an optional CLI wrapper) suited to use in web server environments (never raise an exception, never write to stdout, etc.) as an implementation of the markdown parser that follows thesyntax rules and the behavior of the original (markdown.pl) implementation as reasonably as possible (see differences for a few exceptions).
• Provide an Extension API which makes it possible to change and/or extend the behavior of the parser.

Note

This is not a CommonMark implementation; nor is it trying to be! Python-Markdown was developed long before the CommonMark specification was released and has always (mostly) followed the syntax rules and behavior of the original reference implementation. No accommodations have been made to address the changes which CommonMark has suggested. It is recommended that you look elsewhere if you want an implementation which follows the CommonMark specification.

Features¶

In addition to the basic markdown syntax, Python-Markdown supports the following features:

• International Input
  Python-Markdown will accept input in any language supported by Unicode including bi-directional text. In fact the test suite includes documents written in Russian and Arabic.
• Extensions
  Various extensions are provided (includingextra) to change and/or extend the base syntax. Additionally, a public Extension API is available to write your own extensions.
• Output Formats
  Python-Markdown can output documents with either HTML or XHTML style tags. See the Library Reference for details.
• Command Line Interface
  In addition to being a Python Library, acommand line script is available for your convenience.

Differences¶

While Python-Markdown strives to fully implement markdown as described in thesyntax rules, the rules can be interpreted in different ways and different implementations occasionally vary in their behavior (see theBabelmark FAQfor some examples). Known and intentional differences found in Python-Markdown are summarized below:

• Middle-Word Emphasis
  Python-Markdown defaults to ignoring middle-word emphasis (and strong emphasis). In other words, some_long_filename.txt will not becomesome<em>long</em>filename.txt. This can be switched off if desired. See the Legacy EM Extension for details.
• Indentation/Tab Length
  The syntax rulesclearly state that when a list item consists of multiple paragraphs, “each subsequent paragraph in a list item must be indented by either 4 spaces or one tab” (emphasis added). However, many implementations do not enforce this rule and allow less than 4 spaces of indentation. The implementers of Python-Markdown consider it a bug to not enforce this rule.
  This applies to any block level elements nested in a list, including paragraphs, sub-lists, blockquotes, code blocks, etc. They must always be indented by at least four spaces (or one tab) for each level of nesting.
  In the event that one would prefer different behavior,tab_length can be set to whatever length is desired. Be warned however, as this will affect indentation for all aspects of the syntax (including root level code blocks). Alternatively, athird party extension may offer a solution that meets your needs.
• Consecutive Lists
  While the syntax rules are not clear on this, many implementations (including the original) do not end one list and start a second list when the list marker (asterisks, pluses, hyphens, and numbers) changes. For consistency, Python-Markdown maintains the same behavior with no plans to change in the foreseeable future. That said, the Sane List Extensionis available to provide a less surprising behavior.

Support¶

You may report bugs, ask for help, and discuss various other issues on the bug tracker.