cpython/README

This is Python version 3.1 alpha 2
==================================

Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Python Software Foundation.
All rights reserved.

Python 3.x is a new version of the language, which is incompatible with the
2.x line of releases.  The language is mostly the same, but many details,
especially how built-in objects like dictionaries and strings work, have
changed considerably, and a lot of deprecated features have finally been
removed.


Release Schedule
----------------

See PEP 375 for release details: http://www.python.org/dev/peps/pep-0375/


Documentation
-------------

Documentation for Python 3.1 is online, updated twice a day:

    http://docs.python.org/dev/3.1/

All documentation is also available online at the Python web site
(http://docs.python.org/, see below).  It is available online for
occasional reference, or can be downloaded in many formats for faster
access.  The documentation is downloadable in HTML, PostScript, PDF,
LaTeX (through 2.5), and reStructuredText (2.6+) formats; the LaTeX and
reStructuredText versions are primarily for documentation authors,
translators, and people with special formatting requirements.

This is a work in progress; please help improve it!

The design documents for Python 3 are also online.  While the reference
documentation is being updated, the PEPs are often the best source of
information about new features.  Start by reading PEP 3000:

    http://python.org/dev/peps/pep-3000/


What's New
----------

For an overview of what's new in Python 3, see Guido van Rossum's blog at
artima.com:

    http://www.artima.com/weblogs/index.jsp?blogger=guido

We try to eventually have a comprehensive overview of the changes in
the "What's New in Python 3.1" document, found at

    http://docs.python.org/dev/3.1/whatsnew/3.1

Please help write it!

For a more detailed change log, read Misc/NEWS (though this file, too,
is incomplete, and also doesn't list anything merged in from the 2.6
release under development).

If you want to install multiple versions of Python see the section below
entitled "Installing multiple versions".


Proposals for enhancement
-------------------------

If you have a proposal to change Python, you may want to send an email to the
comp.lang.python or python-ideas mailing lists for inital feedback. A Python
Enhancement Proposal (PEP) may be submitted if your idea gains ground. All
current PEPs, as well as guidelines for submitting a new PEP, are listed at
http://www.python.org/dev/peps/.


Converting From Python 2.x to 3.x
---------------------------------

Python starting with 2.6 will contain features to help locating code that
needs to be changed, such as optional warnings when deprecated features are
used, and backported versions of certain key Python 3.x features.


Testing
-------

To test the interpreter, type "make test" in the top-level directory.
This runs the test set twice (once with no compiled files, once with
the compiled files left by the previous test run).  The test set
produces some output.  You can generally ignore the messages about
skipped tests due to optional features which can't be imported.
If a message is printed about a failed test or a traceback or core
dump is produced, something is wrong.  On some Linux systems (those
that are not yet using glibc 6), test_strftime fails due to a
non-standard implementation of strftime() in the C library. Please
ignore this, or upgrade to glibc version 6.

By default, tests are prevented from overusing resources like disk space and
memory.  To enable these tests, run "make testall".

IMPORTANT: If the tests fail and you decide to mail a bug report,
*don't* include the output of "make test".  It is useless.  Run the
failing test manually, as follows:

        ./python Lib/test/regrtest.py -v test_whatever

(substituting the top of the source tree for '.' if you built in a
different directory).  This runs the test in verbose mode.


Installing multiple versions
----------------------------

On Unix and Mac systems if you intend to install multiple versions of Python
using the same installation prefix (--prefix argument to the configure
script) you must take care that your primary python executable is not
overwritten by the installation of a different versio.  All files and
directories installed using "make altinstall" contain the major and minor
version and can thus live side-by-side.  "make install" also creates
${prefix}/bin/python which refers to ${prefix}/bin/pythonX.Y.  If you intend
to install multiple versions using the same prefix you must decide which
version (if any) is your "primary" version.  Install that version using
"make install".  Install all other versions using "make altinstall".

For example, if you want to install Python 2.5, 2.6 and 3.0 with 2.6 being
the primary version, you would execute "make install" in your 2.6 build
directory and "make altinstall" in the others.


Configuration options and variables
-----------------------------------

A source-to-source translation tool, "2to3", can take care of the
mundane task of converting large amounts of source code.  It is not a
complete solution but is complemented by the deprecation warnings in
2.6.  This tool is currently available via the Subversion sandbox:

    http://svn.python.org/view/sandbox/trunk/2to3/


Issue Tracker and Mailing List
------------------------------

We're soliciting bug reports about all aspects of the language.  Fixes
are also welcome, preferable in unified diff format.  Please use the
issue tracker:

    http://bugs.python.org/

If you're not sure whether you're dealing with a bug or a feature, use
the mailing list:

    python-dev@python.org

To subscribe to the list, use the mailman form:

    http://mail.python.org/mailman/listinfo/python-dev/


Build Instructions
------------------

On Unix, Linux, BSD, OSX, and Cygwin:

    ./configure
    make
    make test
    sudo make install    # or "make altinstall"

You can pass many options to the configure script; run "./configure
--help" to find out more.  On OSX and Cygwin, the executable is called
python.exe; elsewhere it's just python.

On Mac OS X, if you have configured Python with --enable-framework,
you should use "make frameworkinstall" to do the installation.  Note
that this installs the Python executable in a place that is not
normally on your PATH, you may want to set up a symlink in
/usr/local/bin.

On Windows, see PCbuild/readme.txt.

If you wish, you can create a subdirectory and invoke configure from
there.  For example:

    mkdir debug
    cd debug
    ../configure --with-pydebug
    make
    make test

(This will fail if you *also* built at the top-level directory.  You
should do a "make clean" at the toplevel first.)


Copyright and License Information
---------------------------------

Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
Python Software Foundation.
All rights reserved.

Copyright (c) 2000 BeOpen.com.
All rights reserved.

Copyright (c) 1995-2001 Corporation for National Research Initiatives.
All rights reserved.

Copyright (c) 1991-1995 Stichting Mathematisch Centrum.
All rights reserved.

See the file "LICENSE" for information on the history of this
software, terms & conditions for usage, and a DISCLAIMER OF ALL
WARRANTIES.

This Python distribution contains *no* GNU General Public License
(GPL) code, so it may be used in proprietary projects.  There are
interfaces to some GNU code but these are entirely optional.

All trademarks referenced herein are property of their respective
holders.