Switch docs to MKDocs (#602)

Fixes #601. Merged in 6f87b32 from the md3 branch and did a lot of cleanup.

Changes include:

* Removed old docs build tool, templates, etc.

* Added MkDocs config file, etc.

* filename.txt => filename.md

* pythonhost.org/Markdown => Python-Markdown.github.io

* Markdown lint and other cleanup.

* Automate pages deployment in makefile with `mkdocs gh-deploy`

    Assumes a git remote is set up named "pages". Do

        git remote add pages https://github.com/Python-Markdown/Python-Markdown.github.io.git

    ... before running `make deploy` the first time.

1 files changed, 720 insertions, 0 deletions

diff --git a/docs/extensions/api.md b/docs/extensions/api.md
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+title:      Extensions API
+
+# Writing Extensions for Python-Markdown
+
+Python-Markdown includes an API for extension writers to plug their own
+custom functionality and/or syntax into the parser. There are Preprocessors
+which allow you to alter the source before it is passed to the parser,
+inline patterns which allow you to add, remove or override the syntax of
+any inline elements, and Postprocessors which allow munging of the
+output of the parser before it is returned. If you really want to dive in,
+there are also Blockprocessors which are part of the core BlockParser.
+
+As the parser builds an [ElementTree][ElementTree] object which is later rendered
+as Unicode text, there are also some helpers provided to ease manipulation of
+the tree. Each part of the API is discussed in its respective section below.
+Additionally, reading the source of some [Available Extensions][] may be
+helpful. For example, the [Footnotes][] extension uses most of the features
+documented here.
+
+## Preprocessors {: #preprocessors }
+
+Preprocessors munge the source text before it is passed into the Markdown
+core. This is an excellent place to clean up bad syntax, extract things the
+parser may otherwise choke on and perhaps even store it for later retrieval.
+
+Preprocessors should inherit from `markdown.preprocessors.Preprocessor` and
+implement a `run` method with one argument `lines`. The `run` method of
+each Preprocessor will be passed the entire source text as a list of Unicode
+strings. Each string will contain one line of text. The `run` method should
+return either that list, or an altered list of Unicode strings.
+
+A pseudo example:
+
+```python
+from markdown.preprocessors import Preprocessor
+
+class MyPreprocessor(Preprocessor):
+    def run(self, lines):
+        new_lines = []
+        for line in lines:
+            m = MYREGEX.match(line)
+            if m:
+                # do stuff
+            else:
+                new_lines.append(line)
+        return new_lines
+```
+
+## Inline Patterns {: #inlinepatterns }
+
+Inline Patterns implement the inline HTML element syntax for Markdown such as
+`*emphasis*` or `[links](http://example.com)`. Pattern objects should be
+instances of classes that inherit from `markdown.inlinepatterns.Pattern` or
+one of its children. Each pattern object uses a single regular expression and
+must have the following methods:
+
+* **`getCompiledRegExp()`**:
+
+    Returns a compiled regular expression.
+
+* **`handleMatch(m)`**:
+
+    Accepts a match object and returns an ElementTree element of a plain
+    Unicode string.
+
+Also, Inline Patterns can define the property `ANCESTOR_EXCLUDES` with either
+a list or tuple of undesirable ancestors. The pattern should not match if it
+would cause the content to be a descendant of one of the defined tag names.
+
+Note that any regular expression returned by `getCompiledRegExp` must capture
+the whole block. Therefore, they should all start with `r'^(.*?)'` and end
+with `r'(.*?)!'`. When using the default `getCompiledRegExp()` method
+provided in the `Pattern` you can pass in a regular expression without that
+and `getCompiledRegExp` will wrap your expression for you and set the
+`re.DOTALL` and `re.UNICODE` flags. This means that the first group of your
+match will be `m.group(2)` as `m.group(1)` will match everything before the
+pattern.
+
+For an example, consider this simplified emphasis pattern:
+
+```python
+from markdown.inlinepatterns import Pattern
+from markdown.util import etree
+
+class EmphasisPattern(Pattern):
+    def handleMatch(self, m):
+        el = etree.Element('em')
+        el.text = m.group(3)
+        return el
+```
+
+As discussed in [Integrating Your Code Into Markdown][], an instance of this
+class will need to be provided to Markdown. That instance would be created
+like so:
+
+```python
+# an oversimplified regex
+MYPATTERN = r'\*([^*]+)\*'
+# pass in pattern and create instance
+emphasis = EmphasisPattern(MYPATTERN)
+```
+
+Actually it would not be necessary to create that pattern (and not just because
+a more sophisticated emphasis pattern already exists in Markdown). The fact is,
+that example pattern is not very DRY. A pattern for `**strong**` text would
+be almost identical, with the exception that it would create a 'strong' element.
+Therefore, Markdown provides a number of generic pattern classes that can
+provide some common functionality. For example, both emphasis and strong are
+implemented with separate instances of the `SimpleTagPattern` listed below.
+Feel free to use or extend any of the Pattern classes found at
+`markdown.inlinepatterns`.
+
+### Generic Pattern Classes
+
+* **`SimpleTextPattern(pattern)`**:
+
+    Returns simple text of `group(2)` of a `pattern`.
+
+* **`SimpleTagPattern(pattern, tag)`**:
+
+    Returns an element of type "`tag`" with a text attribute of `group(3)`
+    of a `pattern`. `tag` should be a string of a HTML element (i.e.: 'em').
+
+* **`SubstituteTagPattern(pattern, tag)`**:
+
+    Returns an element of type "`tag`" with no children or text (i.e.: `br`).
+
+There may be other Pattern classes in the Markdown source that you could extend
+or use as well. Read through the source and see if there is anything you can
+use. You might even get a few ideas for different approaches to your specific
+situation.
+
+## Treeprocessors {: #treeprocessors }
+
+Treeprocessors manipulate an ElementTree object after it has passed through the
+core BlockParser. This is where additional manipulation of the tree takes
+place. Additionally, the InlineProcessor is a Treeprocessor which steps through
+the tree and runs the Inline Patterns on the text of each Element in the tree.
+
+A Treeprocessor should inherit from `markdown.treeprocessors.Treeprocessor`,
+over-ride the `run` method which takes one argument `root` (an ElementTree
+object) and either modifies that root element and returns `None` or returns a
+new ElementTree object.
+
+A pseudo example:
+
+```python
+from markdown.treeprocessors import Treeprocessor
+
+class MyTreeprocessor(Treeprocessor):
+    def run(self, root):
+        root.text = 'modified content'
+```
+
+Note that Python class methods return `None` by default when no `return`
+statement is defined.  Additionally all Python variables refer to objects by
+reference.  Therefore, the above `run` method modifies the `root` element
+in place and returns `None`. The changes made to the `root` element and its
+children are retained.
+
+Some may be inclined to return the modified `root` element. While that would
+work, it would cause a copy of the entire ElementTree to be generated each
+time the Treeprocessor is run. Therefore, it is generally expected that
+the `run` method would only return `None` or a new ElementTree object.
+
+For specifics on manipulating the ElementTree, see
+[Working with the ElementTree][workingwithetree] below.
+
+## Postprocessors {: #postprocessors }
+
+Postprocessors manipulate the document after the ElementTree has been
+serialized into a string. Postprocessors should be used to work with the
+text just before output.
+
+A Postprocessor should inherit from `markdown.postprocessors.Postprocessor`
+and over-ride the `run` method which takes one argument `text` and returns
+a Unicode string.
+
+Postprocessors are run after the ElementTree has been serialized back into
+Unicode text.  For example, this may be an appropriate place to add a table of
+contents to a document:
+
+```python
+from markdown.postprocessors import Postprocessor
+
+class TocPostprocessor(Postprocessor):
+    def run(self, text):
+        return MYMARKERRE.sub(MyToc, text)
+```
+
+## BlockParser {: #blockparser }
+
+Sometimes, Preprocessors, Treeprocessors, Postprocessors, and Inline Patterns
+are not going to do what you need. Perhaps you want a new type of block type
+that needs to be integrated into the core parsing. In such a situation, you can
+add/change/remove functionality of the core `BlockParser`. The BlockParser is
+composed of a number of Blockprocessors. The BlockParser steps through each
+block of text (split by blank lines) and passes each block to the appropriate
+Blockprocessor. That Blockprocessor parses the block and adds it to the
+ElementTree. The
+[Definition Lists][] extension would be a good example of an extension that
+adds/modifies Blockprocessors.
+
+A Blockprocessor should inherit from `markdown.blockprocessors.BlockProcessor`
+and implement both the `test` and `run` methods.
+
+The `test` method is used by BlockParser to identify the type of block.
+Therefore the `test` method must return a Boolean value. If the test returns
+`True`, then the BlockParser will call that Blockprocessor's `run` method.
+If it returns `False`, the BlockParser will move on to the next
+Blockprocessor.
+
+The **`test`** method takes two arguments:
+
+* **`parent`**: The parent ElementTree Element of the block. This can be useful
+  as the block may need to be treated differently if it is inside a list, for
+  example.
+
+* **`block`**: A string of the current block of text. The test may be a
+  simple string method (such as `block.startswith(some_text)`) or a complex
+  regular expression.
+
+The **`run`** method takes two arguments:
+
+* **`parent`**: A pointer to the parent ElementTree Element of the block. The run
+  method will most likely attach additional nodes to this parent. Note that
+  nothing is returned by the method. The ElementTree object is altered in place.
+
+* **`blocks`**: A list of all remaining blocks of the document. Your run
+  method must remove (pop) the first block from the list (which it altered in
+  place - not returned) and parse that block. You may find that a block of text
+  legitimately contains multiple block types. Therefore, after processing the
+  first type, your processor can insert the remaining text into the beginning
+  of the `blocks` list for future parsing.
+
+Please be aware that a single block can span multiple text blocks. For example,
+The official Markdown syntax rules state that a blank line does not end a
+Code Block. If the next block of text is also indented, then it is part of
+the previous block. Therefore, the BlockParser was specifically designed to
+address these types of situations. If you notice the `CodeBlockProcessor`,
+in the core, you will note that it checks the last child of the `parent`.
+If the last child is a code block (`<pre><code>...</code></pre>`), then it
+appends that block to the previous code block rather than creating a new
+code block.
+
+Each Blockprocessor has the following utility methods available:
+
+* **`lastChild(parent)`**:
+
+    Returns the last child of the given ElementTree Element or `None` if it
+    had no children.
+
+* **`detab(text)`**:
+
+    Removes one level of indent (four spaces by default) from the front of each
+    line of the given text string.
+
+* **`looseDetab(text, level)`**:
+
+    Removes "level" levels of indent (defaults to 1) from the front of each line
+    of the given text string. However, this methods allows secondary lines to
+    not be indented as does some parts of the Markdown syntax.
+
+Each Blockprocessor also has a pointer to the containing BlockParser instance at
+`self.parser`, which can be used to check or alter the state of the parser.
+The BlockParser tracks it's state in a stack at `parser.state`. The state
+stack is an instance of the `State` class.
+
+**`State`** is a subclass of `list` and has the additional methods:
+
+* **`set(state)`**:
+
+    Set a new state to string `state`. The new state is appended to the end
+    of the stack.
+
+* **`reset()`**:
+
+    Step back one step in the stack. The last state at the end is removed from
+    the stack.
+
+* **`isstate(state)`**:
+
+    Test that the top (current) level of the stack is of the given string
+    `state`.
+
+Note that to ensure that the state stack does not become corrupted, each time a
+state is set for a block, that state *must* be reset when the parser finishes
+parsing that block.
+
+An instance of the **`BlockParser`** is found at `Markdown.parser`.
+`BlockParser` has the following methods:
+
+* **`parseDocument(lines)`**:
+
+    Given a list of lines, an ElementTree object is returned. This should be
+    passed an entire document and is the only method the `Markdown` class
+    calls directly.
+
+* **`parseChunk(parent, text)`**:
+
+    Parses a chunk of markdown text composed of multiple blocks and attaches
+    those blocks to the `parent` Element. The `parent` is altered in place
+    and nothing is returned. Extensions would most likely use this method for
+    block parsing.
+
+* **`parseBlocks(parent, blocks)`**:
+
+    Parses a list of blocks of text and attaches those blocks to the `parent`
+    Element. The `parent` is altered in place and nothing is returned. This
+    method will generally only be used internally to recursively parse nested
+    blocks of text.
+
+While is is not recommended, an extension could subclass or completely replace
+the `BlockParser`. The new class would have to provide the same public API.
+However, be aware that other extensions may expect the core parser provided
+and will not work with such a drastically different parser.
+
+## Working with the ElementTree {: #working_with_et }
+
+As mentioned, the Markdown parser converts a source document to an
+[ElementTree][ElementTree] object before serializing that back to Unicode text.
+Markdown has provided some helpers to ease that manipulation within the context
+of the Markdown module.
+
+First, to get access to the ElementTree module import ElementTree from
+`markdown` rather than importing it directly. This will ensure you are using
+the same version of ElementTree as markdown. The module is found at
+`markdown.util.etree` within Markdown.
+
+```python
+from markdown.util import etree
+```
+
+`markdown.util.etree` tries to import ElementTree from any known location,
+first as a standard library module (from `xml.etree` in Python 2.5), then as
+a third party package (ElementTree). In each instance, `cElementTree` is
+tried first, then ElementTree if the faster C implementation is not
+available on your system.
+
+Sometimes you may want text inserted into an element to be parsed by
+[Inline Patterns][]. In such a situation, simply insert the text as you normally
+would and the text will be automatically run through the Inline Patterns.
+However, if you do *not* want some text to be parsed by Inline Patterns,
+then insert the text as an `AtomicString`.
+
+```python
+from markdown.util import AtomicString
+some_element.text = AtomicString(some_text)
+```
+
+Here's a basic example which creates an HTML table (note that the contents of
+the second cell (`td2`) will be run through Inline Patterns latter):
+
+```python
+table = etree.Element("table")
+table.set("cellpadding", "2")                      # Set cellpadding to 2
+tr = etree.SubElement(table, "tr")                 # Add child tr to table
+td1 = etree.SubElement(tr, "td")                   # Add child td1 to tr
+td1.text = markdown.util.AtomicString("Cell content") # Add plain text content
+td2 = etree.SubElement(tr, "td")                   # Add second td to tr
+td2.text = "*text* with **inline** formatting."    # Add markup text
+table.tail = "Text after table"                    # Add text after table
+```
+
+You can also manipulate an existing tree. Consider the following example which
+adds a `class` attribute to `<a>` elements:
+
+```python
+def set_link_class(self, element):
+    for child in element:
+        if child.tag == "a":
+              child.set("class", "myclass") #set the class attribute
+          set_link_class(child) # run recursively on children
+```
+
+For more information about working with ElementTree see the ElementTree
+[Documentation](http://effbot.org/zone/element-index.htm)
+([Python Docs](http://docs.python.org/lib/module-xml.etree.ElementTree.html)).
+
+## Integrating Your Code Into Markdown {: #integrating_into_markdown }
+
+Once you have the various pieces of your extension built, you need to tell
+Markdown about them and ensure that they are run in the proper sequence.
+Markdown accepts an `Extension` instance for each extension. Therefore, you
+will need to define a class that extends `markdown.extensions.Extension` and
+over-rides the `extendMarkdown` method. Within this class you will manage
+configuration options for your extension and attach the various processors and
+patterns to the Markdown instance.
+
+It is important to note that the order of the various processors and patterns
+matters. For example, if we replace `http://...` links with `<a>` elements,
+and *then* try to deal with  inline HTML, we will end up with a mess.
+Therefore, the various types of processors and patterns are stored within an
+instance of the Markdown class in [OrderedDict][]s. Your `Extension` class
+will need to manipulate those OrderedDicts appropriately. You may insert
+instances of your processors and patterns into the appropriate location in an
+OrderedDict, remove a built-in instance, or replace a built-in instance with
+your own.
+
+### `extendMarkdown` {: #extendmarkdown }
+
+The `extendMarkdown` method of a `markdown.extensions.Extension` class
+accepts two arguments:
+
+* **`md`**:
+
+    A pointer to the instance of the Markdown class. You should use this to
+    access the [OrderedDict][]s of processors and patterns. They are found
+    under the following attributes:
+
+    * `md.preprocessors`
+    * `md.inlinePatterns`
+    * `md.parser.blockprocessors`
+    * `md.treeprocessors`
+    * `md.postprocessors`
+
+    Some other things you may want to access in the markdown instance are:
+
+    * `md.htmlStash`
+    * `md.output_formats`
+    * `md.set_output_format()`
+    * `md.output_format`
+    * `md.serializer`
+    * `md.registerExtension()`
+    * `md.html_replacement_text`
+    * `md.tab_length`
+    * `md.enable_attributes`
+    * `md.smart_emphasis`
+
+* **`md_globals`**:
+
+    Contains all the various global variables within the markdown module.
+
+!!! Warning
+    With access to the above items, theoretically you have the option to
+    change anything through various [monkey_patching][] techniques. However,
+    you should be aware that the various undocumented parts of markdown may
+    change without notice and your monkey_patches may break with a new release.
+    Therefore, what you really should be doing is inserting processors and
+    patterns into the markdown pipeline. Consider yourself warned!
+
+[monkey_patching]: http://en.wikipedia.org/wiki/Monkey_patch
+
+A simple example:
+
+```python
+from markdown.extensions import Extension
+
+class MyExtension(Extension):
+    def extendMarkdown(self, md, md_globals):
+        # Insert instance of 'mypattern' before 'references' pattern
+        md.inlinePatterns.add('mypattern', MyPattern(md), '<references')
+```
+
+### OrderedDict {: #ordereddict }
+
+An OrderedDict is a dictionary like object that retains the order of it's
+items. The items are ordered in the order in which they were appended to
+the OrderedDict. However, an item can also be inserted into the OrderedDict
+in a specific location in relation to the existing items.
+
+Think of OrderedDict as a combination of a list and a dictionary as it has
+methods common to both. For example, you can get and set items using the
+`od[key] = value` syntax and the methods `keys()`, `values()`, and
+`items()` work as expected with the keys, values and items returned in the
+proper order. At the same time, you can use `insert()`, `append()`, and
+`index()` as you would with a list.
+
+Generally speaking, within Markdown extensions you will be using the special
+helper method `add()` to add additional items to an existing OrderedDict.
+
+The `add()` method accepts three arguments:
+
+* **`key`**: A string. The key is used for later reference to the item.
+
+* **`value`**: The object instance stored in this item.
+
+* **`location`**: The items location in relation to other items.
+
+    Note that the location can consist of a few different values:
+
+    * The special strings `"_begin"` and `"_end"` insert that item at the
+      beginning or end of the OrderedDict respectively.
+
+    * A less-than sign (`<`) followed by an existing key (i.e.:
+      `"<somekey"`) inserts that item before the existing key.
+
+    * A greater-than sign (`>`) followed by an existing key (i.e.:
+      `">somekey"`) inserts that item after the existing key.
+
+Consider the following example:
+
+```pycon
+>>> from markdown.odict import OrderedDict
+>>> od = OrderedDict()
+>>> od['one'] =  1           # The same as: od.add('one', 1, '_begin')
+>>> od['three'] = 3          # The same as: od.add('three', 3, '>one')
+>>> od['four'] = 4           # The same as: od.add('four', 4, '_end')
+>>> od.items()
+[("one", 1), ("three", 3), ("four", 4)]
+```
+
+Note that when building an OrderedDict in order, the extra features of the
+`add` method offer no real value and are not necessary. However, when
+manipulating an existing OrderedDict, `add` can be very helpful. So let's
+insert another item into the OrderedDict.
+
+```pycon
+>>> od.add('two', 2, '>one')         # Insert after 'one'
+>>> od.values()
+[1, 2, 3, 4]
+```
+
+Now let's insert another item.
+
+```pycon
+>>> od.add('two-point-five', 2.5, '<three') # Insert before 'three'
+>>> od.keys()
+["one", "two", "two-point-five", "three", "four"]
+```
+
+Note that we also could have set the location of "two-point-five" to be 'after two'
+(i.e.: `'>two'`). However, it's unlikely that you will have control over the
+order in which extensions will be loaded, and this could affect the final
+sorted order of an OrderedDict. For example, suppose an extension adding
+"two-point-five" in the above examples was loaded before a separate extension
+which adds 'two'. You may need to take this into consideration when adding your
+extension components to the various markdown OrderedDicts.
+
+Once an OrderedDict is created, the items are available via key:
+
+```python
+MyNode = od['somekey']
+```
+
+Therefore, to delete an existing item:
+
+```python
+del od['somekey']
+```
+
+To change the value of an existing item (leaving location unchanged):
+
+```python
+od['somekey'] = MyNewObject()
+```
+
+To change the location of an existing item:
+
+```python
+t.link('somekey', '<otherkey')
+```
+
+### registerExtension {: #registerextension }
+
+Some extensions may need to have their state reset between multiple runs of the
+Markdown class. For example, consider the following use of the [Footnotes][]
+extension:
+
+```python
+md = markdown.Markdown(extensions=['footnotes'])
+html1 = md.convert(text_with_footnote)
+md.reset()
+html2 = md.convert(text_without_footnote)
+```
+
+Without calling `reset`, the footnote definitions from the first document will
+be inserted into the second document as they are still stored within the class
+instance. Therefore the `Extension` class needs to define a `reset` method
+that will reset the state of the extension (i.e.: `self.footnotes = {}`).
+However, as many extensions do not have a need for `reset`, `reset` is only
+called on extensions that are registered.
+
+To register an extension, call `md.registerExtension` from within your
+`extendMarkdown` method:
+
+```python
+def extendMarkdown(self, md, md_globals):
+    md.registerExtension(self)
+    # insert processors and patterns here
+```
+
+Then, each time `reset` is called on the Markdown instance, the `reset`
+method of each registered extension will be called as well. You should also
+note that `reset` will be called on each registered extension after it is
+initialized the first time. Keep that in mind when over-riding the extension's
+`reset` method.
+
+### Configuration Settings {: #configsettings }
+
+If an extension uses any parameters that the user may want to change,
+those parameters should be stored in `self.config` of your
+`markdown.extensions.Extension` class in the following format:
+
+```python
+class MyExtension(markdown.extensions.Extension):
+    def __init__(self, **kwargs):
+        self.config = {'option1' : ['value1', 'description1'],
+                       'option2' : ['value2', 'description2'] }
+        super(MyExtension, self).__init__(**kwargs)
+```
+
+When implemented this way the configuration parameters can be over-ridden at
+run time (thus the call to `super`). For example:
+
+```python
+markdown.Markdown(extensions=[MyExtension(option1='other value'])
+```
+
+Note that if a keyword is passed in that is not already defined in
+`self.config`, then a `KeyError` is raised.
+
+The `markdown.extensions.Extension` class and its subclasses have the
+following methods available to assist in working with configuration settings:
+
+* **`getConfig(key [, default])`**:
+
+    Returns the stored value for the given `key` or `default` if the `key`
+    does not exist. If not set, `default` returns an empty string.
+
+* **`getConfigs()`**:
+
+    Returns a dict of all key/value pairs.
+
+* **`getConfigInfo()`**:
+
+    Returns all configuration descriptions as a list of tuples.
+
+* **`setConfig(key, value)`**:
+
+    Sets a configuration setting for `key` with the given `value`. If `key` is
+    unknown, a `KeyError` is raised. If the previous value of `key` was
+    a Boolean value, then `value` is converted to a Boolean value. If
+    the previous value of `key` is `None`, then `value` is converted to
+    a Boolean value except when it is `None`. No conversion takes place
+    when the previous value of `key` is a string.
+
+* **`setConfigs(items)`**:
+
+    Sets multiple configuration settings given a dict of key/value pairs.
+
+### `makeExtension` {: #makeextension }
+
+As noted in the [library reference] an instance of an extension can be passed
+directly to Markdown. In fact, this is the preferred way to use third-party
+extensions.
+
+For example:
+
+```python
+import markdown
+import myextension
+myext = myextension.MyExtension(option='value')
+md = markdown.Markdown(extensions=[myext])
+```
+
+Markdown also accepts "named" third party extensions for those occasions when it
+is impractical to import an extension directly (from the command line or from
+within templates).
+
+The "name" of your extension must be a string consisting of the importable path to
+your module using Python's dot notation. Therefore, if you are providing a library
+to your users and would like to include a custom markdown extension within your
+library, that extension would be named `"mylib.mdext.myext"` where `mylib/mdext/myext.py`
+contains the extension and the `mylib` directory is on the PYTHONPATH.
+
+The string can also include the name of the class separated by a colon.
+Therefore, if you were to import the class like this:
+
+```python
+from path.to.module import SomeExtensionClass
+```
+
+Then the named extension would comprise this string:
+
+```python
+"path.to.module:SomeExtensionClass"
+```
+
+You do not need to do anything special to support this feature. As long as your
+extension class is able to be imported, a user can include it with the above syntax.
+
+The above two methods are especially useful if you need to implement a large
+number of extensions with more than one residing in a module. However, if you do
+not want to require that your users include the class name in their string, you
+must define only one extension per module and that module must contain a
+module-level function called `makeExtension` that accepts `**kwargs` and returns
+an extension instance.
+
+For example:
+
+```python
+class MyExtension(markdown.extensions.Extension)
+    # Define extension here...
+
+def makeExtension(**kwargs):
+    return MyExtension(**kwargs)
+```
+
+When Markdown is passed the "name" of your extension as a dot notation string,
+it will import the module and call the `makeExtension` function to initiate your
+extension.
+
+[Preprocessors]: #preprocessors
+[Inline Patterns]: #inlinepatterns
+[Treeprocessors]: #treeprocessors
+[Postprocessors]: #postprocessors
+[BlockParser]: #blockparser
+[workingwithetree]: #working_with_et
+[Integrating your code into Markdown]: #integrating_into_markdown
+[extendMarkdown]: #extendmarkdown
+[OrderedDict]: #ordereddict
+[registerExtension]: #registerextension
+[Config Settings]: #configsettings
+[makeExtension]: #makeextension
+[ElementTree]: http://effbot.org/zone/element-index.htm
+[Available Extensions]: index.md
+[Footnotes]: https://github.com/Python-Markdown/mdx_footnotes
+[Definition Lists]: https://github.com/Python-Markdown/mdx_definition_lists
+[library reference]: ../reference.md