Remove documentation of machinery that is now in traitlets

And add link to it with intersphinx

docs/source/conf.py

@@ -1,253 +1,255
 # -*- coding: utf-8 -*-
 #
 # IPython documentation build configuration file.
 
 # NOTE: This file has been edited manually from the auto-generated one from
 # sphinx.  Do NOT delete and re-generate.  If any changes from sphinx are
 # needed, generate a scratch one and merge by hand any new fields needed.
 
 #
 # This file is execfile()d with the current directory set to its containing dir.
 #
 # The contents of this file are pickled, so don't put values in the namespace
 # that aren't pickleable (module imports are okay, they're removed automatically).
 #
 # All configuration values have a default value; values that are commented out
 # serve to show the default value.
 
 import sys, os
 
 ON_RTD = os.environ.get('READTHEDOCS', None) == 'True'
 
 if ON_RTD:
     # Mock the presence of matplotlib, which we don't have on RTD
     # see
     # http://read-the-docs.readthedocs.org/en/latest/faq.html
     tags.add('rtd')
     
 # If your extensions are in another directory, add it here. If the directory
 # is relative to the documentation root, use os.path.abspath to make it
 # absolute, like shown here.
 sys.path.insert(0, os.path.abspath('../sphinxext'))
 
 # We load the ipython release info into a dict by explicit execution
 iprelease = {}
 exec(compile(open('../../IPython/core/release.py').read(), '../../IPython/core/release.py', 'exec'),iprelease)
 
 # General configuration
 # ---------------------
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
     'matplotlib.sphinxext.mathmpl',
     'matplotlib.sphinxext.only_directives',
     'matplotlib.sphinxext.plot_directive',
     'sphinx.ext.autodoc',
     'sphinx.ext.autosummary',
     'sphinx.ext.doctest',
     'sphinx.ext.inheritance_diagram',
     'sphinx.ext.intersphinx',
     'IPython.sphinxext.ipython_console_highlighting',
     'IPython.sphinxext.ipython_directive',
     'numpydoc',  # to preprocess docstrings
     'github',  # for easy GitHub links
     'magics',
 ]
 
 if ON_RTD:
     # Remove extensions not currently supported on RTD
     extensions.remove('matplotlib.sphinxext.only_directives')
     extensions.remove('matplotlib.sphinxext.mathmpl')
     extensions.remove('matplotlib.sphinxext.plot_directive')
     extensions.remove('IPython.sphinxext.ipython_directive')
     extensions.remove('IPython.sphinxext.ipython_console_highlighting')
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
 
 # The suffix of source filenames.
 source_suffix = '.rst'
 
 if iprelease['_version_extra'] == 'dev':
     rst_prolog = """
     .. note::
 
         This documentation is for a development version of IPython. There may be
         significant differences from the latest stable release.
 
     """
 
 # The master toctree document.
 master_doc = 'index'
 
 # General substitutions.
 project = 'IPython'
 copyright = 'The IPython Development Team'
 
 # ghissue config
 github_project_url = "https://github.com/ipython/ipython"
 
 # numpydoc config
 numpydoc_show_class_members = False # Otherwise Sphinx emits thousands of warnings
 numpydoc_class_members_toctree = False
 
 # The default replacements for |version| and |release|, also used in various
 # other places throughout the built documents.
 #
 # The full version, including alpha/beta/rc tags.
 release = "%s" % iprelease['version']
 # Just the X.Y.Z part, no '-dev'
 version = iprelease['version'].split('-', 1)[0]
 
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
 #today = ''
 # Else, today_fmt is used as the format for a strftime call.
 today_fmt = '%B %d, %Y'
 
 # List of documents that shouldn't be included in the build.
 #unused_docs = []
 
 # Exclude these glob-style patterns when looking for source files. They are
 # relative to the source/ directory.
 exclude_patterns = ['whatsnew/pr']
 
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
 #add_function_parentheses = True
 
 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
 #add_module_names = True
 
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
 #show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'
 
 # Set the default role so we can use `foo` instead of ``foo``
 default_role = 'literal'
 
 # Options for HTML output
 # -----------------------
 
 # The style sheet to use for HTML and HTML Help pages. A file of that name
 # must exist either in Sphinx' static/ path, or in one of the custom paths
 # given in html_static_path.
 html_style = 'default.css'
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
 #html_title = None
 
 # The name of an image file (within the static path) to place at the top of
 # the sidebar.
 #html_logo = None
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ['_static']
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
 html_last_updated_fmt = '%b %d, %Y'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
 #html_use_smartypants = True
 
 # Custom sidebar templates, maps document names to template names.
 #html_sidebars = {}
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
 html_additional_pages = {
     'interactive/htmlnotebook': 'notebook_redirect.html',
     'interactive/notebook': 'notebook_redirect.html',
     'interactive/nbconvert': 'notebook_redirect.html',
     'interactive/public_server': 'notebook_redirect.html',
 }
 
 # If false, no module index is generated.
 #html_use_modindex = True
 
 # If true, the reST sources are included in the HTML build as _sources/<name>.
 #html_copy_source = True
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
 #html_use_opensearch = ''
 
 # If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
 #html_file_suffix = ''
 
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'ipythondoc'
 
 intersphinx_mapping = {'python': ('http://docs.python.org/2/', None),
-                       'rpy2': ('http://rpy.sourceforge.net/rpy2/doc-2.4/html/', None)}
+                       'rpy2': ('http://rpy.sourceforge.net/rpy2/doc-2.4/html/', None),
+                       'traitlets': ('http://traitlets.readthedocs.org/en/latest/', None),
+                      }
 
 # Options for LaTeX output
 # ------------------------
 
 # The paper size ('letter' or 'a4').
 latex_paper_size = 'letter'
 
 # The font size ('10pt', '11pt' or '12pt').
 latex_font_size = '11pt'
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, document class [howto/manual]).
 
 latex_documents = [
     ('index', 'ipython.tex', 'IPython Documentation',
      u"""The IPython Development Team""", 'manual', True),
     ('parallel/winhpc_index', 'winhpc_whitepaper.tex',
      'Using IPython on Windows HPC Server 2008',
      u"Brian E. Granger", 'manual', True)
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
 #latex_logo = None
 
 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
 #latex_use_parts = False
 
 # Additional stuff for the LaTeX preamble.
 #latex_preamble = ''
 
 # Documents to append as an appendix to all manuals.
 #latex_appendices = []
 
 # If false, no module index is generated.
 latex_use_modindex = True
 
 
 # Options for texinfo output
 # --------------------------
 
 texinfo_documents = [
   (master_doc, 'ipython', 'IPython Documentation',
    'The IPython Development Team',
    'IPython',
    'IPython Documentation',
    'Programming',
    1),
 ]
 
 modindex_common_prefix = ['IPython.']
 
 
 # Cleanup
 # -------
 # delete release info to avoid pickling errors from sphinx
 
 del iprelease

docs/source/config/intro.rst

@@ -1,156 +1,156
 =====================================
 Introduction to IPython configuration
 =====================================
 
 .. _setting_config:
 
 Setting configurable options
 ============================
 
 Many of IPython's classes have configurable attributes (see
 :doc:`options/index` for the list). These can be
 configured in several ways.
 
 Python config files
 -------------------
 
 To create the blank config files, run::
 
     ipython profile create [profilename]
 
 If you leave out the profile name, the files will be created for the
 ``default`` profile (see :ref:`profiles`). These will typically be
 located in :file:`~/.ipython/profile_default/`, and will be named
 :file:`ipython_config.py`, :file:`ipython_notebook_config.py`, etc.
 The settings in :file:`ipython_config.py` apply to all IPython commands.
 
 The files typically start by getting the root config object::
 
     c = get_config()
 
 You can then configure class attributes like this::
 
     c.InteractiveShell.automagic = False
 
 Be careful with spelling--incorrect names will simply be ignored, with
 no error.
 
 To add to a collection which may have already been defined elsewhere,
 you can use methods like those found on lists, dicts and sets: append,
-extend, :meth:`~traitlets.config.loader.LazyConfigValue.prepend` (like
+extend, :meth:`~traitlets.config.LazyConfigValue.prepend` (like
 extend, but at the front), add and update (which works both for dicts
 and sets)::
 
     c.InteractiveShellApp.extensions.append('Cython')
 
 .. versionadded:: 2.0
    list, dict and set methods for config values
 
 Example config file
 ```````````````````
 
 ::
 
     # sample ipython_config.py
     c = get_config()
 
     c.TerminalIPythonApp.display_banner = True
     c.InteractiveShellApp.log_level = 20
     c.InteractiveShellApp.extensions = [
         'myextension'
     ]
     c.InteractiveShellApp.exec_lines = [
         'import numpy',
         'import scipy'
     ]
     c.InteractiveShellApp.exec_files = [
         'mycode.py',
         'fancy.ipy'
     ]
     c.InteractiveShell.autoindent = True
     c.InteractiveShell.colors = 'LightBG'
     c.InteractiveShell.confirm_exit = False
     c.InteractiveShell.deep_reload = True
     c.InteractiveShell.editor = 'nano'
     c.InteractiveShell.xmode = 'Context'
 
     c.PromptManager.in_template  = 'In [\#]: '
     c.PromptManager.in2_template = '   .\D.: '
     c.PromptManager.out_template = 'Out[\#]: '
     c.PromptManager.justify = True
 
     c.PrefilterManager.multi_line_specials = True
 
     c.AliasManager.user_aliases = [
      ('la', 'ls -al')
     ]
 
 
 Command line arguments
 ----------------------
 
 Every configurable value can be set from the command line, using this
 syntax::
 
     ipython --ClassName.attribute=value
 
 Many frequently used options have short aliases and flags, such as
 ``--matplotlib`` (to integrate with a matplotlib GUI event loop) or
 ``--pdb`` (automatic post-mortem debugging of exceptions).
 
 To see all of these abbreviated options, run::
 
     ipython --help
     ipython notebook --help
     # etc.
 
 Options specified at the command line, in either format, override
 options set in a configuration file.
 
 The config magic
 ----------------
 
 You can also modify config from inside IPython, using a magic command::
 
     %config IPCompleter.greedy = True
 
 At present, this only affects the current session - changes you make to
 config are not saved anywhere. Also, some options are only read when
 IPython starts, so they can't be changed like this.
 
 .. _profiles:
 
 Profiles
 ========
 
 IPython can use multiple profiles, with separate configuration and
 history. By default, if you don't specify a profile, IPython always runs
 in the ``default`` profile. To use a new profile::
 
     ipython profile create foo   # create the profile foo
     ipython --profile=foo        # start IPython using the new profile
 
 Profiles are typically stored in :ref:`ipythondir`, but you can also keep
 a profile in the current working directory, for example to distribute it
 with a project. To find a profile directory on the filesystem::
 
     ipython locate profile foo
 
 .. _ipythondir:
 
 The IPython directory
 =====================
 
 IPython stores its files---config, command history and extensions---in
 the directory :file:`~/.ipython/` by default.
 
 .. envvar:: IPYTHONDIR
 
    If set, this environment variable should be the path to a directory,
    which IPython will use for user data. IPython will create it if it
    does not exist.
 
 .. option:: --ipython-dir=<path>
 
    This command line option can also be used to override the default
    IPython directory.

docs/source/development/config.rst

@@ -1,566 +1,148
 .. _config_overview:
 
 ============================================
 Overview of the IPython configuration system
 ============================================
 
-This section describes the IPython configuration system. 
-
-The main concepts
-=================
-
-There are a number of abstractions that the IPython configuration system uses.
-Each of these abstractions is represented by a Python class.
-
-Configuration object: :class:`~traitlets.config.loader.Config`
-    A configuration object is a simple dictionary-like class that holds
-    configuration attributes and sub-configuration objects. These classes
-    support dotted attribute style access (``cfg.Foo.bar``) in addition to the
-    regular dictionary style access (``cfg['Foo']['bar']``).
-    The Config object is a wrapper around a simple dictionary with some convenience methods,
-    such as merging and automatic section creation.
-
-Application: :class:`~traitlets.config.application.Application`
-    An application is a process that does a specific job. The most obvious
-    application is the :command:`ipython` command line program. Each
-    application reads *one or more* configuration files and a single set of
-    command line options
-    and then produces a master configuration object for the application. This
-    configuration object is then passed to the configurable objects that the
-    application creates. These configurable objects implement the actual logic
-    of the application and know how to configure themselves given the
-    configuration object.
-    
-    Applications always have a `log` attribute that is a configured Logger.
-    This allows centralized logging configuration per-application.
-
-Configurable: :class:`~traitlets.config.configurable.Configurable`
-    A configurable is a regular Python class that serves as a base class for
-    all main classes in an application. The
-    :class:`~traitlets.config.configurable.Configurable` base class is
-    lightweight and only does one things.
-
-    This :class:`~traitlets.config.configurable.Configurable` is a subclass
-    of :class:`~traitlets.HasTraits` that knows how to configure
-    itself. Class level traits with the metadata ``config=True`` become
-    values that can be configured from the command line and configuration
-    files.
-    
-    Developers create :class:`~traitlets.config.configurable.Configurable`
-    subclasses that implement all of the logic in the application. Each of
-    these subclasses has its own configuration information that controls how
-    instances are created.
-
-Singletons: :class:`~traitlets.config.configurable.SingletonConfigurable`
-    Any object for which there is a single canonical instance. These are
-    just like Configurables, except they have a class method 
-    :meth:`~traitlets.config.configurable.SingletonConfigurable.instance`,
-    that returns the current active instance (or creates one if it
-    does not exist).  Examples of singletons include
-    :class:`~traitlets.config.application.Application`s and
-    :class:`~IPython.core.interactiveshell.InteractiveShell`.  This lets
-    objects easily connect to the current running Application without passing
-    objects around everywhere.  For instance, to get the current running 
-    Application instance, simply do: ``app = Application.instance()``.
-
-
-.. note::
-
-    Singletons are not strictly enforced - you can have many instances
-    of a given singleton class, but the :meth:`instance` method will always
-    return the same one.
-
-Having described these main concepts, we can now state the main idea in our
-configuration system: *"configuration" allows the default values of class
-attributes to be controlled on a class by class basis*. Thus all instances of
-a given class are configured in the same way. Furthermore, if two instances
-need to be configured differently, they need to be instances of two different
-classes. While this model may seem a bit restrictive, we have found that it
-expresses most things that need to be configured extremely well. However, it
-is possible to create two instances of the same class that have different
-trait values. This is done by overriding the configuration.
-
-Now, we show what our configuration objects and files look like.
-
-Configuration objects and files
-===============================
-
-A configuration object is little more than a wrapper around a dictionary.
-A configuration *file* is simply a mechanism for producing that object.
-The main IPython configuration file is a plain Python script,
-which can perform extensive logic to populate the config object.
-IPython 2.0 introduces a JSON configuration file,
-which is just a direct JSON serialization of the config dictionary,
-which is easily processed by external software.
-
-When both Python and JSON configuration file are present, both will be loaded,
-with JSON configuration having higher priority.
-
-Python configuration Files
---------------------------
-
-A Python configuration file is a pure Python file that populates a configuration object.
-This configuration object is a :class:`~traitlets.config.loader.Config` instance.
-While in a configuration file, to get a reference to this object, simply call the :func:`get_config`
-function, which is available in the global namespace of the script.
-
-Here is an example of a super simple configuration file that does nothing::
-
-    c = get_config()
-
-Once you get a reference to the configuration object, you simply set
-attributes on it.  All you have to know is:
-
-* The name of the class to configure.
-* The name of the attribute.
-* The type of each attribute.
-
-The answers to these questions are provided by the various
-:class:`~traitlets.config.configurable.Configurable` subclasses that an
-application uses. Let's look at how this would work for a simple configurable
-subclass::
-
-    # Sample configurable:
-    from traitlets.config.configurable import Configurable
-    from traitlets import Int, Float, Unicode, Bool
-    
-    class MyClass(Configurable):
-        name = Unicode(u'defaultname', config=True)
-        ranking = Int(0, config=True)
-        value = Float(99.0)
-        # The rest of the class implementation would go here..
-
-In this example, we see that :class:`MyClass` has three attributes, two
-of which (``name``, ``ranking``) can be configured.  All of the attributes
-are given types and default values.  If a :class:`MyClass` is instantiated,
-but not configured, these default values will be used.  But let's see how
-to configure this class in a configuration file::
-
-    # Sample config file
-    c = get_config()
-    
-    c.MyClass.name = 'coolname'
-    c.MyClass.ranking = 10
-
-After this configuration file is loaded, the values set in it will override
-the class defaults anytime a :class:`MyClass` is created.  Furthermore,
-these attributes will be type checked and validated anytime they are set.
-This type checking is handled by the :mod:`traitlets` module,
-which provides the :class:`Unicode`, :class:`Int` and :class:`Float` types.
-In addition to these traitlets, the :mod:`traitlets` provides
-traitlets for a number of other types.
-
-.. note::
-
-    Underneath the hood, the :class:`Configurable` base class is a subclass of
-    :class:`traitlets.HasTraits`. The
-    :mod:`traitlets` module is a lightweight version of
-    :mod:`enthought.traits`. Our implementation is a pure Python subset
-    (mostly API compatible) of :mod:`enthought.traits` that does not have any
-    of the automatic GUI generation capabilities. Our plan is to achieve 100%
-    API compatibility to enable the actual :mod:`enthought.traits` to
-    eventually be used instead. Currently, we cannot use
-    :mod:`enthought.traits` as we are committed to the core of IPython being
-    pure Python.
-
-It should be very clear at this point what the naming convention is for 
-configuration attributes::
-
-    c.ClassName.attribute_name = attribute_value
-
-Here, ``ClassName`` is the name of the class whose configuration attribute you
-want to set, ``attribute_name`` is the name of the attribute you want to set
-and ``attribute_value`` the the value you want it to have. The ``ClassName``
-attribute of ``c`` is not the actual class, but instead is another
-:class:`~traitlets.config.loader.Config` instance.
-
-.. note::
-
-    The careful reader may wonder how the ``ClassName`` (``MyClass`` in
-    the above example) attribute of the configuration object ``c`` gets
-    created. These attributes are created on the fly by the
-    :class:`~traitlets.config.loader.Config` instance, using a simple naming
-    convention. Any attribute of a :class:`~traitlets.config.loader.Config`
-    instance whose name begins with an uppercase character is assumed to be a
-    sub-configuration and a new empty :class:`~traitlets.config.loader.Config`
-    instance is dynamically created for that attribute. This allows deeply
-    hierarchical information created easily (``c.Foo.Bar.value``) on the fly.
-
-JSON configuration Files
-------------------------
-
-A JSON configuration file is simply a file that contains a
-:class:`~traitlets.config.loader.Config` dictionary serialized to JSON.
-A JSON configuration file has the same base name as a Python configuration file,
-but with a .json extension.
-
-Configuration described in previous section could be written as follows in a
-JSON configuration file:
-
-.. sourcecode:: json
-
-    {
-      "version": "1.0",
-      "MyClass": {
-        "name": "coolname",
-        "ranking": 10
-      }
-    }
-
-JSON configuration files can be more easily generated or processed by programs
-or other languages.
-
-
-Configuration files inheritance
-===============================
-
-.. note::
-
-    This section only apply to Python configuration files.
-
-Let's say you want to have different configuration files for various purposes.
-Our configuration system makes it easy for one configuration file to inherit
-the information in another configuration file. The :func:`load_subconfig`
-command can be used in a configuration file for this purpose. Here is a simple
-example that loads all of the values from the file :file:`base_config.py`::
-
-    # base_config.py
-    c = get_config()
-    c.MyClass.name = 'coolname'
-    c.MyClass.ranking = 100
-
-into the configuration file :file:`main_config.py`::
-
-    # main_config.py
-    c = get_config()
-    
-    # Load everything from base_config.py
-    load_subconfig('base_config.py')
-    
-    # Now override one of the values
-    c.MyClass.name = 'bettername'
-
-In a situation like this the :func:`load_subconfig` makes sure that the
-search path for sub-configuration files is inherited from that of the parent.
-Thus, you can typically put the two in the same directory and everything will
-just work.
-
-You can also load configuration files by profile, for instance:
-
-.. sourcecode:: python
-
-    load_subconfig('ipython_config.py', profile='default')
-
-to inherit your default configuration as a starting point.
-
-
-Class based configuration inheritance
-=====================================
-
-There is another aspect of configuration where inheritance comes into play.
-Sometimes, your classes will have an inheritance hierarchy that you want
-to be reflected in the configuration system.  Here is a simple example::
-
-    from traitlets.config.configurable import Configurable
-    from traitlets import Int, Float, Unicode, Bool
-    
-    class Foo(Configurable):
-        name = Unicode(u'fooname', config=True)
-        value = Float(100.0, config=True)
-    
-    class Bar(Foo):
-        name = Unicode(u'barname', config=True)
-        othervalue = Int(0, config=True)
-
-Now, we can create a configuration file to configure instances of :class:`Foo`
-and :class:`Bar`::
-
-    # config file
-    c = get_config()
-    
-    c.Foo.name = u'bestname'
-    c.Bar.othervalue = 10
-
-This class hierarchy and configuration file accomplishes the following:
-
-* The default value for :attr:`Foo.name` and :attr:`Bar.name` will be
-  'bestname'.  Because :class:`Bar` is a :class:`Foo` subclass it also
-  picks up the configuration information for :class:`Foo`.
-* The default value for :attr:`Foo.value` and :attr:`Bar.value` will be
-  ``100.0``, which is the value specified as the class default.
-* The default value for :attr:`Bar.othervalue` will be 10 as set in the
-  configuration file.  Because :class:`Foo` is the parent of :class:`Bar`
-  it doesn't know anything about the :attr:`othervalue` attribute.
-
-
-.. _ipython_dir:
+This section describes the IPython configuration system. This is based on
+:mod:`traitlets.config`; see that documentation for more information
+about the overall architecture.
 
 Configuration file location
 ===========================
 
 So where should you put your configuration files? IPython uses "profiles" for
 configuration, and by default, all profiles will be stored in the so called
 "IPython directory". The location of this directory is determined by the
 following algorithm:
 
 * If the ``ipython-dir`` command line flag is given, its value is used.
 
-* If not, the value returned by :func:`IPython.utils.path.get_ipython_dir`
+* If not, the value returned by :func:`IPython.paths.get_ipython_dir`
   is used. This function will first look at the :envvar:`IPYTHONDIR`
   environment variable and then default to :file:`~/.ipython`.
   Historical support for the :envvar:`IPYTHON_DIR` environment variable will
   be removed in a future release.
 
 For most users, the configuration directory will be :file:`~/.ipython`.
 
 Previous versions of IPython on Linux would use the XDG config directory,
 creating :file:`~/.config/ipython` by default. We have decided to go
 back to :file:`~/.ipython` for consistency among systems. IPython will
 issue a warning if it finds the XDG location, and will move it to the new
 location if there isn't already a directory there.
 
 Once the location of the IPython directory has been determined, you need to know
 which profile you are using. For users with a single configuration, this will
 simply be 'default', and will be located in 
 :file:`<IPYTHONDIR>/profile_default`.
 
 The next thing you need to know is what to call your configuration file. The
 basic idea is that each application has its own default configuration filename.
 The default named used by the :command:`ipython` command line program is
 :file:`ipython_config.py`, and *all* IPython applications will use this file.
 Other applications, such as the parallel :command:`ipcluster` scripts or the
 QtConsole will load their own config files *after* :file:`ipython_config.py`. To
 load a particular configuration file instead of the default, the name can be
 overridden by the ``config_file`` command line flag.
 
 To generate the default configuration files, do::
 
     $ ipython profile create
 
 and you will have a default :file:`ipython_config.py` in your IPython directory
 under :file:`profile_default`. If you want the default config files for the
 :mod:`IPython.parallel` applications, add ``--parallel`` to the end of the
 command-line args.
 
 
 Locating these files
 --------------------
 
 From the command-line, you can quickly locate the IPYTHONDIR or a specific
 profile with:
 
 .. sourcecode:: bash
 
     $ ipython locate
     /home/you/.ipython
     
     $ ipython locate profile foo
     /home/you/.ipython/profile_foo
 
 These map to the utility functions: :func:`IPython.utils.path.get_ipython_dir`
 and :func:`IPython.utils.path.locate_profile` respectively.
 
 
 .. _profiles_dev:
 
 Profiles
 ========
 
 A profile is a directory containing configuration and runtime files, such as
 logs, connection info for the parallel apps, and your IPython command history.
 
 The idea is that users often want to maintain a set of configuration files for
 different purposes: one for doing numerical computing with NumPy and SciPy and
 another for doing symbolic computing with SymPy. Profiles make it easy to keep a
 separate configuration files, logs, and histories for each of these purposes.
 
 Let's start by showing how a profile is used:
 
 .. code-block:: bash
 
     $ ipython --profile=sympy
 
 This tells the :command:`ipython` command line program to get its configuration
 from the "sympy" profile. The file names for various profiles do not change. The
 only difference is that profiles are named in a special way. In the case above,
 the "sympy" profile means looking for :file:`ipython_config.py` in :file:`<IPYTHONDIR>/profile_sympy`.
 
 The general pattern is this: simply create a new profile with:
 
 .. code-block:: bash
 
     $ ipython profile create <name>
 
 which adds a directory called ``profile_<name>`` to your IPython directory. Then
 you can load this profile by adding ``--profile=<name>`` to your command line
 options. Profiles are supported by all IPython applications.
 
 IPython ships with some sample profiles in :file:`IPython/config/profile`. If
 you create profiles with the name of one of our shipped profiles, these config
 files will be copied over instead of starting with the automatically generated
 config files.
 
+IPython extends the config loader for Python files so that you can inherit
+config from another profile. To do this, use a line like this in your Python
+config file:
+
+.. sourcecode:: python
+
+    load_subconfig('ipython_config.py', profile='default')
+
 Security Files
 --------------
 
 If you are using the notebook, qtconsole, or parallel code, IPython stores
 connection information in small JSON files in the active profile's security
 directory. This directory is made private, so only you can see the files inside. If
 you need to move connection files around to other computers, this is where they will
 be. If you want your code to be able to open security files by name, we have a
 convenience function :func:`IPython.utils.path.get_security_file`, which will return
 the absolute path to a security file from its filename and [optionally] profile
 name.
 
 .. _startup_files:
 
 Startup Files
 -------------
 
 If you want some code to be run at the beginning of every IPython session with
 a particular profile, the easiest way is to add Python (``.py``) or 
 IPython (``.ipy``) scripts to your :file:`<profile>/startup` directory. Files
 in this directory will always be executed as soon as the IPython shell is 
 constructed, and before any other code or scripts you have specified. If you 
 have multiple files in the startup directory, they will be run in 
 lexicographical order, so you can control the ordering by adding a '00-' 
 prefix.
-
-
-.. _commandline:
-
-Command-line arguments
-======================
-
-IPython exposes *all* configurable options on the command-line. The command-line
-arguments are generated from the Configurable traits of the classes associated
-with a given Application.  Configuring IPython from the command-line may look
-very similar to an IPython config file
-
-IPython applications use a parser called
-:class:`~traitlets.config.loader.KeyValueLoader` to load values into a Config
-object.  Values are assigned in much the same way as in a config file:
-
-.. code-block:: bash
-
-    $ ipython --InteractiveShell.use_readline=False --BaseIPythonApplication.profile='myprofile'
-
-Is the same as adding:
-
-.. sourcecode:: python
-
-    c.InteractiveShell.use_readline=False
-    c.BaseIPythonApplication.profile='myprofile'
-
-to your config file. Key/Value arguments *always* take a value, separated by '='
-and no spaces.
-
-Common Arguments
-----------------
-
-Since the strictness and verbosity of the KVLoader above are not ideal for everyday
-use, common arguments can be specified as flags_ or aliases_.
-
-Flags and Aliases are handled by :mod:`argparse` instead, allowing for more flexible
-parsing. In general, flags and aliases are prefixed by ``--``, except for those
-that are single characters, in which case they can be specified with a single ``-``, e.g.:
-
-.. code-block:: bash
-
-    $ ipython -i -c "import numpy; x=numpy.linspace(0,1)" --profile testing --colors=lightbg
-
-Aliases
-*******
-
-For convenience, applications have a mapping of commonly used traits, so you don't have
-to specify the whole class name:
-
-.. code-block:: bash
-
-    $ ipython --profile myprofile
-    # and
-    $ ipython --profile='myprofile'
-    # are equivalent to
-    $ ipython --BaseIPythonApplication.profile='myprofile'
-
-Flags
-*****
-
-Applications can also be passed **flags**. Flags are options that take no
-arguments. They are simply wrappers for
-setting one or more configurables with predefined values, often True/False.
-
-For instance:
-
-.. code-block:: bash
-
-    $ ipcontroller --debug
-    # is equivalent to
-    $ ipcontroller --Application.log_level=DEBUG
-    # and
-    $ ipython --matplotlib
-    # is equivalent to
-    $ ipython --matplotlib auto
-    # or
-    $ ipython --no-banner
-    # is equivalent to
-    $ ipython --TerminalIPythonApp.display_banner=False
-
-Subcommands
------------
-
-
-Some IPython applications have **subcommands**. Subcommands are modeled after
-:command:`git`, and are called with the form :command:`command subcommand
-[...args]`.  Currently, the QtConsole is a subcommand of terminal IPython:
-
-.. code-block:: bash
-
-    $ ipython qtconsole --profile myprofile
-
-and :command:`ipcluster` is simply a wrapper for its various subcommands (start,
-stop, engines).
-
-.. code-block:: bash
-
-    $ ipcluster start --profile=myprofile -n 4
-
-
-To see a list of the available aliases, flags, and subcommands for an IPython application, simply pass ``-h`` or ``--help``.  And to see the full list of configurable options (*very* long), pass ``--help-all``.
-
-
-Design requirements
-===================
-
-Here are the main requirements we wanted our configuration system to have:
-
-* Support for hierarchical configuration information.
-
-* Full integration with command line option parsers.  Often, you want to read
-  a configuration file, but then override some of the values with command line
-  options.  Our configuration system automates this process and allows each
-  command line option to be linked to a particular attribute in the 
-  configuration hierarchy that it will override.
-
-* Configuration files that are themselves valid Python code. This accomplishes
-  many things. First, it becomes possible to put logic in your configuration
-  files that sets attributes based on your operating system, network setup,
-  Python version, etc. Second, Python has a super simple syntax for accessing
-  hierarchical data structures, namely regular attribute access
-  (``Foo.Bar.Bam.name``). Third, using Python makes it easy for users to
-  import configuration attributes from one configuration file to another.
-  Fourth, even though Python is dynamically typed, it does have types that can
-  be checked at runtime. Thus, a ``1`` in a config file is the integer '1',
-  while a ``'1'`` is a string.
-
-* A fully automated method for getting the configuration information to the
-  classes that need it at runtime. Writing code that walks a configuration
-  hierarchy to extract a particular attribute is painful. When you have
-  complex configuration information with hundreds of attributes, this makes
-  you want to cry.
-
-* Type checking and validation that doesn't require the entire configuration
-  hierarchy to be specified statically before runtime. Python is a very
-  dynamic language and you don't always know everything that needs to be
-  configured when a program starts.
-