Add note about libedit on OS X.

docs/source/install/install.txt

@@ -1,293 +1,300
 Overview
 ========
 
 This document describes the steps required to install IPython.  IPython is
 organized into a number of subpackages, each of which has its own dependencies.
 All of the subpackages come with IPython, so you don't need to download and
 install them separately.  However, to use a given subpackage, you will need to
 install all of its dependencies.
 
 
 Please let us know if you have problems installing IPython or any of its
 dependencies. Officially, IPython requires Python version 2.5 or 2.6.  We
 have *not* yet started to port IPython to Python 3.0.
 
 .. warning::
 
     Officially, IPython supports Python versions 2.5 and 2.6.
 
     IPython 0.10 has only been well tested with Python 2.5 and 2.6.  Parts of
     it may work with Python 2.4, but we do not officially support Python 2.4
     anymore.  If you need to use 2.4, you can still run IPython 0.9.
 
 Some of the installation approaches use the :mod:`setuptools` package and its
 :command:`easy_install` command line program.  In many scenarios, this provides
 the most simple method of installing IPython and its dependencies.  It is not
 required though.  More information about :mod:`setuptools` can be found on its
 website.
 
 More general information about installing Python packages can be found in
 Python's documentation at http://www.python.org/doc/.
 
 Quickstart
 ==========
 
 If you have :mod:`setuptools` installed and you are on OS X or Linux (not
 Windows), the following will download and install IPython *and* the main
 optional dependencies::
 
     $ easy_install ipython[kernel,security,test]
 
 This will get Twisted, zope.interface and Foolscap, which are needed for
 IPython's parallel computing features as well as the nose package, which will
 enable you to run IPython's test suite.  To run IPython's test suite, use the
 :command:`iptest` command::
 
     $ iptest
 
 Read on for more specific details and instructions for Windows.
 
 Installing IPython itself
 =========================
 
 Given a properly built Python, the basic interactive IPython shell will work
 with no external dependencies.  However, some Python distributions
 (particularly on Windows and OS X), don't come with a working :mod:`readline`
 module.  The IPython shell will work without :mod:`readline`, but will lack
 many features that users depend on, such as tab completion and command line
 editing.  See below for details of how to make sure you have a working
 :mod:`readline`.
 
 Installation using easy_install
 -------------------------------
 
 If you have :mod:`setuptools` installed, the easiest way of getting IPython is
 to simple use :command:`easy_install`::
 
 	$ easy_install ipython
 
 That's it.
 
 Installation from source
 ------------------------
 
 If you don't want to use :command:`easy_install`, or don't have it installed,
 just grab the latest stable build of IPython from `here
 <http://ipython.scipy.org/dist/>`_.  Then do the following::
 
 	$ tar -xzf ipython.tar.gz
 	$ cd ipython
 	$ python setup.py install
 
 If you are installing to a location (like ``/usr/local``) that requires higher
 permissions, you may need to run the last command with :command:`sudo`.
 
 Windows
 -------
 
 There are a few caveats for Windows users.  The main issue is that a basic
 ``python setup.py install`` approach won't create ``.bat`` file or Start Menu
 shortcuts, which most users want.  To get an installation with these, you can
 use any of the following alternatives:
 
 1. Install using :command:`easy_install`.
 
 2. Install using our binary ``.exe`` Windows installer, which can be found at
    `here <http://ipython.scipy.org/dist/>`_
 
 3. Install from source, but using :mod:`setuptools` (``python setupegg.py
    install``).
 
 IPython by default runs in a termninal window, but the normal terminal
 application supplied by Microsoft Windows is very primitive.  You may want to
 download the excellent and free Console_ application instead, which is a far
 superior tool.  You can even configure Console to give you by default an
 IPython tab, which is very convenient to create new IPython sessions directly
 from the working terminal.
 
 .. _Console:  http://sourceforge.net/projects/console
 
    
 Installing the development version
 ----------------------------------
 
 It is also possible to install the development version of IPython from our
 `Bazaar <http://bazaar-vcs.org/>`_ source code repository.  To do this you will
 need to have Bazaar installed on your system.  Then just do::
 
 	$ bzr branch lp:ipython
 	$ cd ipython
 	$ python setup.py install
 
 Again, this last step on Windows won't create ``.bat`` files or Start Menu
 shortcuts, so you will have to use one of the other approaches listed above.
 
 Some users want to be able to follow the development branch as it changes.  If
 you have :mod:`setuptools` installed, this is easy. Simply replace the last
 step by::
 
 	$ python setupegg.py develop
 
 This creates links in the right places and installs the command line script to
 the appropriate places.  Then, if you want to update your IPython at any time,
 just do::
 
 	$ bzr pull
 
 Basic optional dependencies
 ===========================
 
 There are a number of basic optional dependencies that most users will want to
 get.  These are:
 
 * readline (for command line editing, tab completion, etc.)
 * nose (to run the IPython test suite)
 * pexpect (to use things like irunner)
 
 If you are comfortable installing these things yourself, have at it, otherwise
 read on for more details.
 
 readline
 --------
 
 In principle, all Python distributions should come with a working
 :mod:`readline` module.  But, reality is not quite that simple.  There are two
 common situations where you won't have a working :mod:`readline` module:
 
 * If you are using the built-in Python on Mac OS X.
 
 * If you are running Windows, which doesn't have a :mod:`readline` module.
 
 On OS X, the built-in Python doesn't not have :mod:`readline` because of
 license issues.  Starting with OS X 10.5 (Leopard), Apple's built-in Python has
 a BSD-licensed not-quite-compatible readline replacement. As of IPython 0.9,
-many of the issues related to the differences between readline and libedit have
-been resolved.  For many users, libedit may be sufficient.
+many of the issues related to the differences between readline and libedit seem
+to have been resolved.  While you may find libedit sufficient, we have
+occasional reports of bugs with it and several developers who use OS X as their
+main environment consider libedit unacceptable for productive, regular use with
+IPython.
 
-Most users on OS X will want to get the full :mod:`readline` module.  To get a
-working :mod:`readline` module, just do (with :mod:`setuptools` installed)::
+Therefore, we *strongly* recommend that on OS X you get the full
+:mod:`readline` module.  We will *not* consider completion/history problems to
+be bugs for IPython if you are using libedit.
+
+To get a working :mod:`readline` module, just do (with :mod:`setuptools`
+installed)::
 
 	$ easy_install readline
 
-.. note:
+.. note::
 
-    Other Python distributions on OS X (such as fink, MacPorts and the 
-    official python.org binaries) already have readline installed so 
-    you don't have to do this step.
+    Other Python distributions on OS X (such as fink, MacPorts and the official
+    python.org binaries) already have readline installed so you likely don't
+    have to do this step.
 
 If needed, the readline egg can be build and installed from source (see the
 wiki page at http://ipython.scipy.org/moin/InstallationOSXLeopard).
 
 On Windows, you will need the PyReadline module. PyReadline is a separate,
 Windows only implementation of readline that uses native Windows calls through
 :mod:`ctypes`. The easiest way of installing PyReadline is you use the binary
 installer available `here <http://ipython.scipy.org/dist/>`_. The :mod:`ctypes`
 module, which comes with Python 2.5 and greater, is required by PyReadline. It
 is available for Python 2.4 at http://python.net/crew/theller/ctypes.
 
 nose
 ----
 
 To run the IPython test suite you will need the :mod:`nose` package.  Nose
 provides a great way of sniffing out and running all of the IPython tests.  The
 simplest way of getting nose, is to use :command:`easy_install`::
 
 	$ easy_install nose
 
 Another way of getting this is to do::
 
     $ easy_install ipython[test]
 
 For more installation options, see the `nose website
 <http://somethingaboutorange.com/mrl/projects/nose/>`_.  Once you have nose
 installed, you can run IPython's test suite using the iptest command::
 
 	$ iptest
 
 
 pexpect
 -------
 
 The `pexpect <http://www.noah.org/wiki/Pexpect>`_ package is used in IPython's
 :command:`irunner` script.  On Unix platforms (including OS X), just do::
 
 	$ easy_install pexpect
 
 Windows users are out of luck as pexpect does not run there.
 
 Dependencies for IPython.kernel (parallel computing)
 ====================================================
 
 The IPython kernel provides a nice architecture for parallel computing.  The
 main focus of this architecture is on interactive parallel computing.  These
 features require a number of additional packages:
 
 * zope.interface (yep, we use interfaces)
 * Twisted (asynchronous networking framework)
 * Foolscap (a nice, secure network protocol)
 * pyOpenSSL (security for network connections)
 
 On a Unix style platform (including OS X), if you want to use :mod:`setuptools`, you can just do::
 
     $ easy_install ipython[kernel]    # the first three
     $ easy_install ipython[security]  # pyOpenSSL
 
 zope.interface and Twisted
 --------------------------
 
 Twisted [Twisted]_ and zope.interface [ZopeInterface]_ are used for networking
 related things. On Unix style platforms (including OS X), the simplest way of
 getting the these is to use :command:`easy_install`::
 
 	$ easy_install zope.interface
 	$ easy_install Twisted
 
 Of course, you can also download the source tarballs from the `Twisted website
 <twistedmatrix.org>`_ and the `zope.interface page at PyPI
 <http://pypi.python.org/pypi/zope.interface>`_ and do the usual ``python
 setup.py install`` if you prefer.
 
 Windows is a bit different.  For zope.interface and Twisted, simply get the latest binary ``.exe`` installer from the Twisted website.  This installer includes both zope.interface and Twisted and should just work.
 
 Foolscap
 --------
 
 Foolscap [Foolscap]_ uses Twisted to provide a very nice secure RPC protocol that we use to implement our parallel computing features.
 
 On all platforms a simple::
 
     $ easy_install foolscap
 
 should work.  You can also download the source tarballs from the `Foolscap
 website <http://foolscap.lothar.com/trac>`_ and do ``python setup.py install``
 if you prefer.
 
 pyOpenSSL
 ---------
 
 IPython requires an older version of pyOpenSSL [pyOpenSSL]_ (0.6 rather than
 the current 0.7).  There are a couple of options for getting this:
 
 1.  Most Linux distributions have packages for pyOpenSSL.
 2.  The built-in Python 2.5 on OS X 10.5 already has it installed.
 3.  There are source tarballs on the pyOpenSSL website.  On Unix-like
     platforms, these can be built using ``python seutp.py install``.
 4.  There is also a binary ``.exe`` Windows installer on the `pyOpenSSL website <http://pyopenssl.sourceforge.net/>`_.
 
 Dependencies for IPython.frontend (the IPython GUI)
 ===================================================
 
 wxPython
 --------
 
 Starting with IPython 0.9, IPython has a new IPython.frontend package that has
 a nice wxPython based IPython GUI.  As you would expect, this GUI requires
 wxPython.  Most Linux distributions have wxPython packages available and the
 built-in Python on OS X comes with wxPython preinstalled.  For Windows, a
 binary installer is available on the `wxPython website
 <http://www.wxpython.org/>`_.
 
 .. [Twisted] Twisted matrix.  http://twistedmatrix.org
 .. [ZopeInterface] http://pypi.python.org/pypi/zope.interface
 .. [Foolscap] Foolscap network protocol.  http://foolscap.lothar.com/trac
 .. [pyOpenSSL] pyOpenSSL.  http://pyopenssl.sourceforge.net