143 lines
4.5 KiB
ReStructuredText
143 lines
4.5 KiB
ReStructuredText
****************************
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What's New In Python 3.2
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****************************
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:Author: Raymond Hettinger
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:Release: |release|
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:Date: |today|
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.. $Id$
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Rules for maintenance:
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* Anyone can add text to this document. Do not spend very much time
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on the wording of your changes, because your text will probably
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get rewritten to some degree.
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* The maintainer will go through Misc/NEWS periodically and add
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changes; it's therefore more important to add your changes to
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Misc/NEWS than to this file.
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* This is not a complete list of every single change; completeness
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is the purpose of Misc/NEWS. Some changes I consider too small
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or esoteric to include. If such a change is added to the text,
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I'll just remove it. (This is another reason you shouldn't spend
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too much time on writing your addition.)
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* If you want to draw your new text to the attention of the
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maintainer, add 'XXX' to the beginning of the paragraph or
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section.
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* It's OK to just add a fragmentary note about a change. For
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example: "XXX Describe the transmogrify() function added to the
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socket module." The maintainer will research the change and
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write the necessary text.
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* You can comment out your additions if you like, but it's not
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necessary (especially when a final release is some months away).
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* Credit the author of a patch or bugfix. Just the name is
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sufficient; the e-mail address isn't necessary.
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* It's helpful to add the bug/patch number as a comment:
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% Patch 12345
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XXX Describe the transmogrify() function added to the socket
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module.
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(Contributed by P.Y. Developer.)
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This saves the maintainer the effort of going through the SVN log
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when researching a change.
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This article explains the new features in Python 3.2, compared to 3.1.
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PEP XXX: Stub
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=============
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Other Language Changes
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======================
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Some smaller changes made to the core Python language are:
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* Stub
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New, Improved, and Deprecated Modules
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=====================================
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* The previously deprecated :func:`string.maketrans` function has been
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removed in favor of the static methods, :meth:`bytes.maketrans` and
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:meth:`bytearray.maketrans`. This change solves the confusion around which
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types were supported by the :mod:`string` module. Now, :class:`str`,
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:class:`bytes`, and :class:`bytearray` each have their own **maketrans** and
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**translate** methods with intermediate translation tables of the
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appropriate type.
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(Contributed by Georg Brandl; :issue:`5675`.)
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* The previously deprecated :func:`contextlib.nested` function has been
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removed in favor of a plain :keyword:`with` statement which can
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accept multiple context managers. The latter technique is faster
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(because it is built-in), and it does a better job finalizing multiple
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context managers when one of them raises an exception.
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(Contributed by Georg Brandl and Mattias Brändström;
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`appspot issue 53094 <http://codereview.appspot.com/53094>`_.)
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Multi-threading
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===============
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* The mechanism for serializing execution of concurrently running Python
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threads (generally known as the GIL or Global Interpreter Lock) has been
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rewritten. Among the objectives were more predictable switching intervals
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and reduced overhead due to lock contention and the number of ensuing
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system calls. The notion of a "check interval" to allow thread switches
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has been abandoned and replaced by an absolute duration expressed in
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seconds. This parameter is tunable through :func:`sys.setswitchinterval()`.
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It currently defaults to 5 milliseconds.
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Additional details about the implementation can be read from a `python-dev
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mailing-list message
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<http://mail.python.org/pipermail/python-dev/2009-October/093321.html>`_
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(however, "priority requests" as exposed in this message have not been
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kept for inclusion).
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(Contributed by Antoine Pitrou)
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* Recursive locks (created with the :func:`threading.RLock` API) now benefit
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from a C implementation which makes them as fast as regular locks, and
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between 10x and 15x faster than their previous pure Python implementation.
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(Contributed by Antoine Pitrou; :issue:`3001`.)
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Optimizations
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=============
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Major performance enhancements have been added:
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* Stub
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IDLE
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====
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* Stub
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Build and C API Changes
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=======================
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Changes to Python's build process and to the C API include:
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* Stub
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Porting to Python 3.2
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=====================
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This section lists previously described changes and other bugfixes
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that may require changes to your code:
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* Stub
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