title:      Fenced Code Blocks Extension
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Fenced Code Blocks
==================

Summary
-------

The Fenced Code Blocks extension adds a secondary way to define code blocks,
which overcomes a few limitations of the indented code blocks.

This extension is included in the standard Markdown library.

Syntax
------

Fenced Code Blocks are defined using the syntax established in 
[PHP Markdown Extra][php].

[php]: http://www.michelf.com/projects/php-markdown/extra/#fenced-code-blocks

Thus, the following text (taken from the above referenced PHP documentation):

    This is a paragraph introducing:

    ~~~~~~~~~~~~~~~~~~~~
    a one-line code block
    ~~~~~~~~~~~~~~~~~~~~

Fenced code blocks can have a blank line as the first  and/or last line of a 
code block and they can also come immediately after a list item without becoming
part of the list.

!!! warning

    Fenced Code Blocks are only supported at the document root level.
    Therefore, they cannot be nested inside lists or blockquotes.

### Language ###

In addition to PHP Extra's syntax, you can define the language of the code 
block for use by syntax highlighters etc. The language will be assigned as a 
class attribute of the ``<code>`` element in the output. Therefore, you should 
define the language as you would a CSS class - ``.language``. For consistency 
with other markdown syntax, the language can *optionally* be wrapped in curly 
brackets:

    ~~~~{.python}
    # python code
    ~~~~

    ~~~~.html
    <p>HTML Document</p>
    ~~~~

The above will output:

    <pre><code class="python"># python code
    </code></pre>
    
    <pre><code class="html">&lt;p&gt;HTML Document&lt;/p&gt;
    </code></pre>

[GitHub][]'s backtick (`\``) syntax is also supported:

    ```python
    # more python code
    ```

[GitHub]: http://github.github.com/github-flavored-markdown/

### Emphasized Lines ###

If you would like to have your fenced code blocks highlighted with the 
[CodeHilite][] extension, simply enable that extension (remember that
[Pygments][] is its dependency) and the language of your fenced code blocks
will be passed in and highlighted appropriately.

Similar to the [colon][] syntax of the CodeHilite extension, fenced code blocks
can also have emphasized certain lines of code.

The lines can be specified with PHP Extra's syntax:

    ~~~~{.python hl_lines="1 3"}
    # This line is emphasized
    # This line isn't
    # This line is emphasized
    ~~~~

... or with GitHub's:

    ```python hl_lines="1 3"
    # This line is emphasized
    # This line isn't
    # This line is emphasized
    ```

[CodeHilite]: code_hilite.html
[Pygments]: http://pygments.org/
[colon]: code_hilite.html#colons

Usage
-----

See [Extensions](index.html) for general extension usage, specify `markdown.extensions.fenced_code`
as the name of the extension.

This extension does not accept any special configuration options.