docs/source/whatsnew/version0.11.txt

=============
 0.11 Series
=============

Release 0.11
============

IPython 0.11 is a *major* overhaul of IPython, two years in the making.  Most
of the code base has been rewritten or at least reorganized, breaking backward
compatibility with several APIs in previous versions.  It is the first major
release in two years, and probably the most significant change to IPython since
its inception.  We plan to have a relatively quick succession of releases, as
people discover new bugs and regressions.  Once we iron out any significant
bugs in this process and settle down the new APIs, this series will become
IPython 1.0.  We encourage feedback now on the core APIs, which we hope to
maintain stable during the 1.0 series.

Chris Fonnesbeck recently wrote an `excellent post`_ that highlights some of
the core new features, with examples and screenshots.  We encourage you
to read it as it provides a great high-level overview that complements the
detailed feature breakdown in this document.

.. _excellent post: http://stronginference.com/weblog/2011/7/15/innovations-in-ipython.html

A quick summary of the major changes (see below for details):

* *Standalone Qt console*: a new rich console has been added to IPython, started
  with `ipython qtconsole`.  In this application we have tried to retain the
  feel of a terminal for fast and efficient workflows, while adding many
  features that a plain text terminal simply can not support, such as inline
  figures, full multiline editing with syntax highlighting, tooltips for
  function calls and much more.

* *High-level parallel computing with ZeroMQ*. Using the same architecture that
  our Qt console is based on, we have completely rewritten our high-level
  parallel computing machinery that in prior versions used the Twisted
  networking framework.  While this change will require users to update their
  codes, the improvements in performance, memory control and internal
  consistency across our codebase convinced us it was a price worth paying.  We
  have tried to explain how to best proceed with this update, and will be happy
  to answer questions that may arise.

* *New model for GUI/plotting support in the terminal*.  Now instead of the
  various `-Xthread` flags we had before, GUI support is provided without the
  use of any threads, by directly integrating GUI event loops with Python's
  `PyOS_InputHook` API.  A new command-line flag `--gui` controls GUI support,
  and it can also be enabled after IPython startup via the new `%gui` magic.

* *A two-process architecture.* The Qt console is the first example of using a
  new model that splits IPython between a kernel process where code is executed
  and a client that handles user interaction.  We plan on also providing
  terminal and web-browser based clients using this infrastructure in future
  releases.  This model allows multiple clients to interact with an IPython
  process through a well-documented protocol using the ZeroMQ networking
  library.

* *Refactoring.* the entire codebase has been refactored, in order to make it
  more modular and easier to contribute to.  IPython has traditionally been a
  hard project to participate because the old codebase was very monolithic.  We
  hope this (ongoing) restructuring will make it easier for new developers to
  join us.

* *Improved unicode support*. We closed many bugs related to unicode input.

* *Python 3*. IPython now runs on Python 3.x.

* *New profile model*. Profiles are now directories that contain all relevant
   infromation for that session, and thus better isolate IPython use-cases.

* *SQLite storage for history*. All history is now stored in a SQLite database,
   providing support for multiple simultaneous sessions that won't clobber each
   other as well as the ability to perform queries on all stored data.

* *New configuration system*. All parts of IPython are now configured via a
   mechanism inspired by the Enthought Traits library.  Any configurable
   element can have its attributes set either via files that now use real
   Python syntax or from the command-line.


Over 60 separate authors have contributed to this release, see :ref:`below
<credits>` for a full list.


Plotting and GUI support in the terminal
----------------------------------------

blah


Qt Console
----------

blah


High-level parallel computing with ZeroMQ
-----------------------------------------


Refactoring
-----------

As of the 0.11 version of IPython, a signifiant portion of the core has been
refactored.  This refactoring is founded on a number of new abstractions.
The main new classes that implement these abstractions are:

* :class:`IPython.utils.traitlets.HasTraits`.
* :class:`IPython.config.configurable.Configurable`.
* :class:`IPython.config.application.Application`.
* :class:`IPython.config.loader.ConfigLoader`.
* :class:`IPython.config.loader.Config`

We are still in the process of writing developer focused documentation about
these classes, but for now our :ref:`configuration documentation
<config_overview>` contains a high level overview of the concepts that these
classes express.

The biggest user-visible change is likely the move to using the config system to
determine the command-line arguments for IPython applications. The benefit of
this is that *all* configurable values in IPython are exposed on the
command-line, but the syntax for specifying values has changed. The gist is that
assigning values is pure Python assignment, so there is always an '=', and never
a leading '-', nor a space separating key from value. Flags exist, to set
multiple values or boolean flags, and these are always prefixed with '--', and
never take arguments.

ZMQ architecture
----------------

There is a new GUI framework for IPython, based on a client-server model in
which multiple clients can communicate with one IPython kernel, using the
ZeroMQ messaging framework. There is already a Qt console client, which can
be started by calling ``ipython qtconsole``. The protocol is :ref:`documented
<messaging>`.

The parallel computing framework has also been rewritten using ZMQ. The
protocol is described :ref:`here <parallel_messages>`, and the code is in the
new :mod:`IPython.parallel` module.

Python 3 support
----------------

A Python 3 version of IPython has been prepared. For the time being, this is
maintained separately and updated from the main codebase. Its code can be found
`here <https://github.com/ipython/ipython-py3k>`_. The parallel computing
components are not perfect on Python3, but most functionality appears to be
working.

Unicode
-------

Entering non-ascii characters in unicode literals (``u"€ø"``) now works
properly on all platforms. However, entering these in byte/string literals
(``"€ø"``) will not work as expected on Windows (or any platform where the
terminal encoding is not UTF-8, as it typically is for Linux & Mac OS X). You
can use escape sequences (``"\xe9\x82"``) to get bytes above 128, or use
unicode literals and encode them. This is a limitation of Python 2 which we
cannot easily work around.

Additional new features
-----------------------

* Added ``Bytes`` traitlet, removing ``Str``.  All 'string' traitlets should
  either be ``Unicode`` if a real string, or ``Bytes`` if a C-string. This
  removes ambiguity and helps the Python 3 transition.

* New magic ``%loadpy`` loads a python file from disk or web URL into
  the current input buffer.

* New magic ``%pastebin`` for sharing code via the 'Lodge it' pastebin.

* New magic ``%precision`` for controlling float and numpy pretty printing.

* IPython applications initiate logging, so any object can gain access to
  a the logger of the currently running Application with:

.. sourcecode:: python

    from IPython.config.application import Application
    logger = Application.instance().log

* You can now get help on an object halfway through typing a command. For
  instance, typing ``a = zip?`` shows the details of :func:`zip`. It also
  leaves the command at the next prompt so you can carry on with it.

* The input history is now written to an SQLite database. The API for
  retrieving items from the history has also been redesigned.

* The :mod:`IPython.extensions.pretty` extension has been moved out of
  quarantine and fully updated to the new extension API.

* New magics for loading/unloading/reloading extensions have been added:
  ``%load_ext``, ``%unload_ext`` and ``%reload_ext``.

* The configuration system and configuration files are brand new. See the
  configuration system :ref:`documentation <config_index>` for more details.

* The :class:`~IPython.core.interactiveshell.InteractiveShell` class is now a
  :class:`~IPython.config.configurable.Configurable` subclass and has traitlets
  that determine the defaults and runtime environment. The ``__init__`` method
  has also been refactored so this class can be instantiated and run without
  the old :mod:`ipmaker` module.

* The methods of :class:`~IPython.core.interactiveshell.InteractiveShell` have
  been organized into sections to make it easier to turn more sections
  of functionality into components.

* The embedded shell has been refactored into a truly standalone subclass of
  :class:`InteractiveShell` called :class:`InteractiveShellEmbed`.  All
  embedding logic has been taken out of the base class and put into the 
  embedded subclass.

* Added methods of :class:`~IPython.core.interactiveshell.InteractiveShell` to
  help it cleanup after itself. The :meth:`cleanup` method controls this. We
  couldn't do this in :meth:`__del__` because we have cycles in our object
  graph that prevent it from being called.

* Created a new module :mod:`IPython.utils.importstring` for resolving
  strings like ``foo.bar.Bar`` to the actual class.

* Completely refactored the :mod:`IPython.core.prefilter` module into
  :class:`~IPython.config.configurable.Configurable` subclasses. Added a new
  layer into the prefilter system, called "transformations" that all new
  prefilter logic should use (rather than the older "checker/handler"
  approach).

* Aliases are now components (:mod:`IPython.core.alias`).

* New top level :func:`~IPython.frontend.terminal.embed.embed` function that can
  be called to embed IPython at any place in user's code. On the first call it
  will create an :class:`~IPython.frontend.terminal.embed.InteractiveShellEmbed`
  instance and call it. In later calls, it just calls the previously created
  :class:`~IPython.frontend.terminal.embed.InteractiveShellEmbed`.

* Created a configuration system (:mod:`IPython.config.configurable`) that is
  based on :mod:`IPython.utils.traitlets`. Configurables are arranged into a
  runtime containment tree (not inheritance) that i) automatically propagates
  configuration information and ii) allows singletons to discover each other in
  a loosely coupled manner. In the future all parts of IPython will be
  subclasses of :class:`~IPython.config.configurable.Configurable`. All IPython
  developers should become familiar with the config system.

* Created a new :class:`~IPython.config.loader.Config` for holding
  configuration information. This is a dict like class with a few extras: i)
  it supports attribute style access, ii) it has a merge function that merges
  two :class:`~IPython.config.loader.Config` instances recursively and iii) it
  will automatically create sub-:class:`~IPython.config.loader.Config`
  instances for attributes that start with an uppercase character.

* Created new configuration loaders in :mod:`IPython.config.loader`. These
  loaders provide a unified loading interface for all configuration
  information including command line arguments and configuration files. We
  have two default implementations based on :mod:`argparse` and plain python
  files.  These are used to implement the new configuration system.

* Created a top-level :class:`Application` class in
  :mod:`IPython.core.application` that is designed to encapsulate the starting
  of any basic Python program. An application loads and merges all the
  configuration objects, constructs the main application, configures and
  initiates logging, and creates and configures any :class:`Configurable`
  instances and then starts the application running. An extended
  :class:`BaseIPythonApplication` class adds logic for handling the
  IPython directory as well as profiles, and all IPython entry points
  extend it.

* The :class:`Type` and :class:`Instance` traitlets now handle classes given
  as strings, like ``foo.bar.Bar``. This is needed for forward declarations.
  But, this was implemented in a careful way so that string to class
  resolution is done at a single point, when the parent
  :class:`~IPython.utils.traitlets.HasTraitlets` is instantiated.

* :mod:`IPython.utils.ipstruct` has been refactored to be a subclass of 
  dict.  It also now has full docstrings and doctests.

* Created a Traits like implementation in :mod:`IPython.utils.traitlets`.  This
  is a pure Python, lightweight version of a library that is similar to
  Enthought's Traits project, but has no dependencies on Enthought's code.  We
  are using this for validation, defaults and notification in our new component
  system.  Although it is not 100% API compatible with Enthought's Traits, we
  plan on moving in this direction so that eventually our implementation could
  be replaced by a (yet to exist) pure Python version of Enthought Traits.

* Added a new module :mod:`IPython.lib.inputhook` to manage the integration
  with GUI event loops using `PyOS_InputHook`.  See the docstrings in this
  module or the main IPython docs for details.

* For users, GUI event loop integration is now handled through the new
  :command:`%gui` magic command.  Type ``%gui?`` at an IPython prompt for
  documentation.

* For developers :mod:`IPython.lib.inputhook` provides a simple interface
  for managing the event loops in their interactive GUI applications.
  Examples can be found in our :file:`docs/examples/lib` directory.

Backwards incompatible changes
------------------------------

* The Twisted-based :mod:`IPython.kernel` has been removed, and completely
  rewritten as :mod:`IPython.parallel`, using ZeroMQ.

* Profiles are now directories. Instead of a profile being a single config file,
  profiles are now self-contained directories. By default, profiles get their
  own IPython history, log files, and everything. To create a new profile, do
  ``ipython profile create <name>``.

* All IPython applications have been rewritten to use
  :class:`~IPython.config.loader.KeyValueConfigLoader`. This means that
  command-line options have changed. Now, all configurable values are accessible
  from the command-line with the same syntax as in a configuration file.

* The command line options ``-wthread``, ``-qthread`` and
  ``-gthread`` have been removed. Use ``--gui=wx``, ``--gui=qt``, ``--gui=gtk``
  instead.

* The extension loading functions have been renamed to
  :func:`load_ipython_extension` and :func:`unload_ipython_extension`.

* :class:`~IPython.core.interactiveshell.InteractiveShell` no longer takes an
  ``embedded`` argument. Instead just use the
  :class:`~IPython.core.interactiveshell.InteractiveShellEmbed` class.

* ``__IPYTHON__`` is no longer injected into ``__builtin__``.

* :meth:`Struct.__init__` no longer takes `None` as its first argument.  It
  must be a :class:`dict` or :class:`Struct`.

* :meth:`~IPython.core.interactiveshell.InteractiveShell.ipmagic` has been
  renamed :meth:`~IPython.core.interactiveshell.InteractiveShell.magic.`

* The functions :func:`ipmagic` and :func:`ipalias` have been removed from
  :mod:`__builtins__`.

* The references to the global
  :class:`~IPython.core.interactivehell.InteractiveShell` instance (``_ip``, and
  ``__IP``) have been removed from the user's namespace. They are replaced by a
  new function called :func:`get_ipython` that returns the current
  :class:`~IPython.core.interactiveshell.InteractiveShell` instance. This
  function is injected into the user's namespace and is now the main way of
  accessing the running IPython.

* Old style configuration files :file:`ipythonrc` and :file:`ipy_user_conf.py`
  are no longer supported. Users should migrate there configuration files to
  the new format described :ref:`here <config_overview>` and :ref:`here
  <configuring_ipython>`.

* The old IPython extension API that relied on :func:`ipapi` has been
  completely removed. The new extension API is described :ref:`here
  <configuring_ipython>`.

* Support for ``qt3`` has been dropped.  Users who need this should use
  previous versions of IPython.

* Removed :mod:`shellglobals` as it was obsolete.

* Removed all the threaded shells in :mod:`IPython.core.shell`. These are no
  longer needed because of the new capabilities in
  :mod:`IPython.lib.inputhook`.

* New top-level sub-packages have been created: :mod:`IPython.core`, 
  :mod:`IPython.lib`, :mod:`IPython.utils`, :mod:`IPython.deathrow`,
  :mod:`IPython.quarantine`.  All existing top-level modules have been
  moved to appropriate sub-packages.  All internal import statements
  have been updated and tests have been added.  The build system (setup.py
  and friends) have been updated.  See :ref:`this section <module_reorg>` of the
  documentation for descriptions of these new sub-packages.

* :mod:`IPython.ipapi` has been moved to :mod:`IPython.core.ipapi`.
  :mod:`IPython.Shell` and :mod:`IPython.iplib` have been split and removed as
  part of the refactor.

* :mod:`Extensions` has been moved to :mod:`extensions` and all existing
  extensions have been moved to either :mod:`IPython.quarantine` or
  :mod:`IPython.deathrow`. :mod:`IPython.quarantine` contains modules that we
  plan on keeping but that need to be updated. :mod:`IPython.deathrow` contains
  modules that are either dead or that should be maintained as third party
  libraries. More details about this can be found :ref:`here <module_reorg>`.

* Previous IPython GUIs in :mod:`IPython.frontend` and :mod:`IPython.gui` are
  likely broken, and have been removed to :mod:`IPython.deathrow` because of the
  refactoring in the core. With proper updates, these should still work.


Known Regressions
-----------------

We do our best to improve IPython, but there are some known regressions in 0.11
relative to 0.10.2.  First of all, there are features that have yet to be
ported to the new APIs, and in order to ensure that all of the installed code
runs for our users, we have moved them to two separate directories in the
source distribution, `quarantine` and `deathrow`.  Finally, we have some other
miscellaneous regressions that we hope to fix as soon as possible.  We now
describe all of these in more detail.

Quarantine
~~~~~~~~~~

These are tools and extensions that we consider relatively easy to update to
the new classes and APIs, but that we simply haven't had time for.  Any user
who is interested in one of these is encouraged to help us by porting it and
submitting a pull request on our `development site`_.

.. _development site:: http://github.com/ipython/ipython

Currently, the quarantine directory contains::

    clearcmd.py            ipy_fsops.py            ipy_signals.py
    envpersist.py          ipy_gnuglobal.py        ipy_synchronize_with.py
    ext_rescapture.py      ipy_greedycompleter.py  ipy_system_conf.py
    InterpreterExec.py     ipy_jot.py              ipy_which.py
    ipy_app_completers.py  ipy_lookfor.py          ipy_winpdb.py
    ipy_autoreload.py      ipy_profile_doctest.py  ipy_workdir.py
    ipy_completers.py      ipy_pydb.py             jobctrl.py
    ipy_editors.py         ipy_rehashdir.py        ledit.py
    ipy_exportdb.py        ipy_render.py           pspersistence.py
    ipy_extutil.py         ipy_server.py           win32clip.py

Deathrow
~~~~~~~~

These packages may be harder to update or make most sense as third-party
libraries.  Some of them are completely obsolete and have been already replaced
by better functionality (we simply haven't had the time to carefully weed them
out so they are kept here for now). Others simply require fixes to code that
the current core team may not be familiar with.  If a tool you were used to is
included here, we encourage you to contact the dev list and we can discuss
whether it makes sense to keep it in IPython (if it can be maintained).

Currently, the deathrow directory contains::

    astyle.py              ipy_defaults.py          ipy_vimserver.py
    dtutils.py             ipy_kitcfg.py            numeric_formats.py
    Gnuplot2.py            ipy_legacy.py            numutils.py
    GnuplotInteractive.py  ipy_p4.py                outputtrap.py
    GnuplotRuntime.py      ipy_profile_none.py      PhysicalQInput.py
    ibrowse.py             ipy_profile_numpy.py     PhysicalQInteractive.py
    igrid.py               ipy_profile_scipy.py     quitter.py*
    ipipe.py               ipy_profile_sh.py        scitedirector.py
    iplib.py               ipy_profile_zope.py      Shell.py
    ipy_constants.py       ipy_traits_completer.py  twshell.py


Other
~~~~~

* The machinery that adds functionality to the 'sh' profile for using IPython
  as your system shell has not been updated to use the new APIs.  As a result,
  only the aesthetic (prompt) changes are still implemented. We intend to fix
  this by 0.12.

* The installation of scripts on Windows was broken without setuptools, so we
  now depend on setuptools on Windows.  We hope to fix setuptools-less
  installation, and then remove the setuptools dependency.


Removed Features
----------------

As part of the updating of IPython, we have removed a few features for the
purpsoes of cleaning up the codebase and interfaces.  These removals are
permanent, but for any item listed below, equivalent functionality is
available.

* The magics Exit and Quit have been dropped as ways to exit IPython. Instead,
  the lowercase forms of both work either as a bare name (``exit``) or a
  function call (``exit()``).  You can assign these to other names using
  exec_lines in the config file.


.. credits_::

Credits
-------

Many users and developers contributed code, features, bug reports and ideas to
this release.  Please do not hesitate in contacting us if we've failed to
acknowledge your contribution here.  In particular, for this release we have
contribution from the following people, a mix of new and regular names (in
alphabetical order by first name):

* Aenugu Sai Kiran Reddy <saikrn08-at-gmail.com>
* andy wilson <wilson.andrew.j+github-at-gmail.com>
* Antonio Cuni <antocuni>
* Barry Wark <barrywark-at-gmail.com>
* Beetoju Anuradha <anu.beethoju-at-gmail.com>
* Benjamin Ragan-Kelley <minrk-at-Mercury.local>
* Brad Reisfeld
* Brian E. Granger <ellisonbg-at-gmail.com>
* Christoph Gohlke <cgohlke-at-uci.edu>
* Cody Precord
* dan.milstein
* Darren Dale <dsdale24-at-gmail.com>
* Dav Clark <davclark-at-berkeley.edu>
* David Warde-Farley <wardefar-at-iro.umontreal.ca>
* epatters <ejpatters-at-gmail.com>
* epatters <epatters-at-caltech.edu>
* epatters <epatters-at-enthought.com>
* Eric Firing <efiring-at-hawaii.edu>
* Erik Tollerud <erik.tollerud-at-gmail.com>
* Evan Patterson <epatters-at-enthought.com>
* Fernando Perez <Fernando.Perez-at-berkeley.edu>
* Gael Varoquaux <gael.varoquaux-at-normalesup.org>
* Gerardo <muzgash-at-Muzpelheim>
* Jason Grout <jason.grout-at-drake.edu>
* John Hunter <jdh2358-at-gmail.com>
* Jens Hedegaard Nielsen <jenshnielsen-at-gmail.com>
* Johann Cohen-Tanugi <johann.cohentanugi-at-gmail.com>
* Jörgen Stenarson <jorgen.stenarson-at-bostream.nu>
* Justin Riley <justin.t.riley-at-gmail.com>
* Kiorky
* Laurent Dufrechou <laurent.dufrechou-at-gmail.com>
* Luis Pedro Coelho <lpc-at-cmu.edu>
* Mani chandra <mchandra-at-iitk.ac.in>
* Mark E. Smith
* Mark Voorhies <mark.voorhies-at-ucsf.edu>
* Martin Spacek <git-at-mspacek.mm.st>
* Michael Droettboom <mdroe-at-stsci.edu>
* MinRK <benjaminrk-at-gmail.com>
* muzuiget <muzuiget-at-gmail.com>
* Nick Tarleton <nick-at-quixey.com>
* Nicolas Rougier <Nicolas.rougier-at-inria.fr>
* Omar Andres Zapata Mesa <andresete.chaos-at-gmail.com>
* Paul Ivanov <pivanov314-at-gmail.com>
* Pauli Virtanen <pauli.virtanen-at-iki.fi>
* Prabhu Ramachandran
* Ramana <sramana9-at-gmail.com>
* Robert Kern <robert.kern-at-gmail.com>
* Sathesh Chandra <satheshchandra88-at-gmail.com>
* Satrajit Ghosh <satra-at-mit.edu>
* Sebastian Busch
* Stefan van der Walt <bzr-at-mentat.za.net>
* Stephan Peijnik <debian-at-sp.or.at>
* Steven Bethard
* Thomas Kluyver <takowl-at-gmail.com>
* Thomas Spura <tomspur-at-fedoraproject.org>
* Tom Fetherston <tfetherston-at-aol.com>
* Tom MacWright
* tzanko
* vankayala sowjanya <hai.sowjanya-at-gmail.com>
* Vivian De Smedt <vds2212-at-VIVIAN>
* Ville M. Vainio <vivainio-at-gmail.com>
* Vishal Vatsa <vishal.vatsa-at-gmail.com>
* Vishnu S G <sgvishnu777-at-gmail.com>
* Walter Doerwald <walter-at-livinglogic.de>

.. note::

    This list was generated with the output of
    ``git log dev-0.11 HEAD --format='* %aN <%aE>' | sed 's/@/\-at\-/' | sed 's/<>//' | sort -u``
    after some cleanup.  If you should be on this list, please add yourself.