GitHub - 1st1/cpython: The Python programming language

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This is Python version 3.7.0 alpha 3+

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Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Python Software Foundation. All rights reserved.

See the end of this file for further copyright and license information.

Contents

General Information

Contributing to CPython

Using Python

Build Instructions

Profile Guided Optimization

Link Time Optimization

What's New

Documentation

Converting From Python 2.x to 3.x

Testing

Installing multiple versions

Issue Tracker and Mailing List

Proposals for enhancement

Release Schedule

Copyright and License Information

General Information

Website:

https://www.python.org

Source code:

https://github.com/python/cpython

Issue tracker:

https://bugs.python.org

Documentation:

https://docs.python.org

Developer's Guide:

https://devguide.python.org/

Contributing to CPython

For more complete instructions on contributing to CPython development, see the

Developer Guide

.

Using Python

Installable Python kits, and information about using Python, are available at

python.org

.

Build Instructions

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

./configure make make test sudo make install This will install Python as python3.

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

On macOS, 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.)

To get an optimized build of Python, configure --enable-optimizations before you run make. This sets the default make targets up to enable Profile Guided Optimization (PGO) and may be used to auto-enable Link Time Optimization (LTO) on some platforms. For more details, see the sections below.

Profile Guided Optimization

PGO takes advantage of recent versions of the GCC or Clang compilers. If ran, make profile-opt will do several steps.

First, the entire Python directory is cleaned of temporary files that may have resulted in a previous compilation.

Then, an instrumented version of the interpreter is built, using suitable compiler flags for each flavour. Note that this is just an intermediary step and the binary resulted after this step is not good for real life workloads, as it has profiling instructions embedded inside.

After this instrumented version of the interpreter is built, the Makefile will automatically run a training workload. This is necessary in order to profile the interpreter execution. Note also that any output, both stdout and stderr, that may appear at this step is suppressed.

Finally, the last step is to rebuild the interpreter, using the information collected in the previous one. The end result will be a Python binary that is optimized and suitable for distribution or production installation.

Link Time Optimization

Enabled via configure's --with-lto flag. LTO takes advantage of the ability of recent compiler toolchains to optimize across the otherwise arbitrary .o file boundary when building final executables or shared libraries for additional performance gains.

What's New

We have a comprehensive overview of the changes in the

What's New in Python 3.7

document. For a more detailed change log, read

Misc/NEWS

, but a full accounting of changes can only be gleaned from the

commit history

.

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

Documentation

Documentation for Python 3.7

is online, updated daily.

It can also be downloaded in many formats for faster access. The documentation is downloadable in HTML, PDF, and reStructuredText formats; the latter version is primarily for documentation authors, translators, and people with special formatting requirements.

For information about building Python's documentation, refer to

Doc/README.rst

.

Converting From Python 2.x to 3.x

Significant backward incompatible changes were made for the release of Python 3.0, which may cause programs written for Python 2 to fail when run with Python 3. For more information about porting your code from Python 2 to Python 3, see the

Porting HOWTO

.

Testing

To test the interpreter, type make test in the top-level directory. 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.

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

If any tests fail, you can re-run the failing test(s) in verbose mode:

make test TESTOPTS="-v test_that_failed" If the failure persists and appears to be a problem with Python rather than your environment, you can

file a bug report

and include relevant output from that command to show the issue.

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 version. 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/python3 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 2.7, 3.6, and 3.7 with 3.7 being the primary version, you would execute make install in your 3.7 build directory and make altinstall in the others.

Issue Tracker and Mailing List

Bug reports are welcome! You can use the

issue tracker

to report bugs, and/or submit pull requests

on GitHub

.

You can also follow development discussion on the

python-dev mailing list

.

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 initial 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

python.org/dev/peps/

.

Release Schedule

See

PEP 537

for Python 3.7 release details.

Copyright and License Information

Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 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.