Adding new docs for configuration/extensions/plugins.

docs/source/config/extensions.txt

@@ -0,0 +1,61 b''
+.. _extensions_overview:
+
+==================
+IPython extensions
+==================
+
+Configuration files are just the first level of customization that IPython
+supports. The next level is that of extensions. An IPython extension is an
+importable Python module that has a a few special function. By defining these
+functions, users can customize IPython by accessing the actual runtime objects
+of IPython.  Here is a sample extension::
+
+    # myextension.py
+
+    def load_ipython_extension(ipython):
+        # The ``ipython`` argument is the currently active 
+        # :class:`InteractiveShell` instance that can be used in any way.
+        # This allows you do to things like register new magics, plugins or
+        # aliases.
+
+    def unload_ipython_extension(ipython):
+        # If you want your extension to be unloadable, put that logic here.
+
+This :func:`load_ipython_extension` function is called after your extension is
+imported and the currently active :class:`InteractiveShell` instance is passed
+as the only argument. You can do anything you want with IPython at that point.
+
+The :func:`load_ipython_extension` will be called again is you load or reload
+the extension again. It is up to the extension author to add code to manage
+that.
+
+You can put your extension modules anywhere you want, as long as they can be
+imported by Python's standard import mechanism. However, to make it easy to
+write extensions, you can also put your extensions in
+``os.path.join(self.ipython_dir, 'extensions')``. This directory is added to
+``sys.path`` automatically.
+
+Using extensions
+================
+
+There are two ways you can tell IPython to use your extension:
+
+1. Listing it in a configuration file.
+2. Using the ``%load_ext`` magic function.
+
+To load an extension called :file:`myextension.py` add the following logic
+to your configuration file::
+
+    c.Global.extensions = [
+        'myextension'
+    ]
+
+To load that same extension at runtime, use the ``%load_ext`` magic::
+
+.. sourcecode:: ipython
+
+    In [1]: %load_ext myextension
+
+To summarize, in conjunction with configuration files and profiles, IPython
+extensions give you complete and flexible control over your IPython
+setup.

docs/source/config/plugins.txt

@@ -0,0 +1,23 b''
+.. _plugins_overview:
+
+===============
+IPython plugins
+===============
+
+IPython has a plugin mechanism that allows users to create new and custom
+runtime components for IPython. Plugins are different from extensions:
+
+* Extensions are used to load plugins.
+* Extensions are a more advanced configuration system that gives you access
+  to the running IPython instance.
+* Plugins add entirely new capabilities to IPython.
+* Plugins are traited and configurable.
+
+At this point, our plugin system is brand new and the documentation is 
+minimal. If you are interested in creating a new plugin, see the following
+files:
+
+* :file:`IPython/extensions/parallemagic.py`
+* :file:`IPython/extensions/pretty.`
+
+As well as our documentation on the configuration system and extensions.

docs/source/config/index.txt

@@ -8,6 +8,8 b' Configuration and customization'
    :maxdepth: 2
 
    overview.txt
+   extensions.txt
+   plugins.txt
    ipython.txt
    editors.txt
    old.txt

docs/source/config/ipython.txt

@@ -133,4 +133,4 b' attributes::'
 
     c.AliasManager.user_aliases = [
      ('la', 'ls -al')
-    ]
  No newline at end of file
+    ]