title:      WikiLinks Extension
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WikiLinks
=========

Summary
-------

The WikiLinks extension adds support for [WikiLinks][]. Specifically, any
``[[bracketed]]`` word is converted to a link.

This extension is included in the standard Markdown library.

[WikiLinks]: http://en.wikipedia.org/wiki/Wikilink

Syntax
------

A ``[[bracketed]]`` word is any combination of  upper or lower case letters,
number, dashes, underscores and spaces surrounded by double brackets. Therefore

    [[Bracketed]]

would produce the following html:

    <a href="/Bracketed/" class="wikilink">Bracketed</a>

Note that wikilinks are automatically assigned `class="wikilink"` making it
easy to style wikilinks differently from other links on a page if one so
desires. See below for ways to alter the class.

Also note that when a space is used, the space is converted to an underscore in
the link but left as-is in the label. Perhaps an example would illustrate this
best:

    [[Wiki Link]]

becomes

    <a href="/Wiki_Link/" class="wikilink">Wiki Link</a>

Usage
-----

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

See the [Library Reference](../reference.html#extensions) for information about
configuring extensions.

The default behavior is to point each link to the document root of the current
domain and close with a trailing slash. Additionally, each link is assigned to
the html class `wikilink`.

The following options are provided to change the default behavior:

* **base_url**: String to append to beginning of URL.

    Default: `'/'`

* **end_url**: String to append to end of URL.

    Default: `'/'`

* **html_class**: CSS class. Leave blank for none.

    Default: `'wikilink'`

* **build_url**: Callable which formats the URL from its parts.

### Examples ###

For an example, let us suppose links should always point to the subdirectory
`/wiki/` and end with `.html`

    >>> html = markdown.markdown(text,
    ...     ['wikilinks(base_url=/wiki/,end_url=.html)']
    ... )

The above would result in the following link for `[[WikiLink]]`.

    <a href="/wiki/WikiLink.html" class="wikilink">WikiLink</a>

If you want to do more that just alter the base and/or end of the URL, you
could also pass in a callable which must accept three arguments (``label``,
``base``, and ``end``). The callable must return the URL in it's entirety.

    def my_url_builder(label, base, end):
        # do stuff
        return url

    md = markdown.Markdown(
            extensions=['wikilinks],
            extension_configs={'wikilinks' : [('build_url', my_url_builder)]}
    )

The option is also provided to change or remove the class attribute.

    >>> html = markdown.markdown(text,
    ...     ['wikilinks(html_class=myclass)']
    ... )

Would cause all wikilinks to be assigned to the class `myclass`.

    <a href="/WikiLink/" class="myclass">WikiLink</a>

Using with Meta-Data extension
------------------------------

The WikiLink Extension also supports the [Meta-Data](meta_data.html) Extension.
Please see the documentation for that extension for specifics. The supported
meta-data keywords are:

* `wiki_base_url`
* `wiki_end_url`
* `wiki_html_class`

When used, the meta-data will override the settings provided through the
`extension_configs` interface.

This document:

    wiki_base_url: http://example.com/
    wiki_end_url:  .html
    wiki_html_class:

    A [[WikiLink]] in the first paragraph.

would result in the following output (notice the blank `wiki_html_class`):

    <p>A <a href="http://example.com/WikiLink.html">WikiLink</a> in the first paragraph.</p>