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sync 2.7.rst with trunk

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Benjamin Peterson 2010-03-21 22:05:32 +00:00
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@ -222,11 +222,70 @@ module, but it's easier to use.
:pep:`378` - Format Specifier for Thousands Separator
PEP written by Raymond Hettinger; implemented by Eric Smith.
PEP 389: The argparse Module for Parsing Command Lines
======================================================
XXX write this section.
.. seealso::
:pep:`389` - argparse - New Command Line Parsing Module
PEP written and implemented by Steven Bethard.
PEP 391: Dictionary-Based Configuration For Logging
====================================================
XXX write this section.
.. seealso::
:pep:`391` - Dictionary-Based Configuration For Logging
PEP written and implemented by Vinay Sajip.
PEP 3106: Dictionary Views
====================================================
XXX write this section.
.. seealso::
:pep:`3106` - Revamping dict.keys(), .values() and .items()
PEP written by Guido van Rossum.
Backported to 2.7 by Alexandre Vassalotti; :issue:`1967`.
Other Language Changes
======================
Some smaller changes made to the core Python language are:
* The syntax for set literals has been backported from Python 3.x.
Curly brackets are used to surround the contents of the resulting
mutable set; set literals are
distinguished from dictionaries by not containing colons and values.
``{}`` continues to represent an empty dictionary; use
``set()`` for an empty set.
>>> {1,2,3,4,5}
set([1, 2, 3, 4, 5])
>>> set()
set([])
>>> {}
{}
Backported by Alexandre Vassalotti; :issue:`2335`.
* Dictionary and set comprehensions are another feature backported from
3.x, generalizing list/generator comprehensions to use
the literal syntax for sets and dictionaries.
>>> {x:x*x for x in range(6)}
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
>>> {'a'*x for x in range(6)}
set(['', 'a', 'aa', 'aaa', 'aaaa', 'aaaaa'])
Backported by Alexandre Vassalotti; :issue:`2333`.
* The :keyword:`with` statement can now use multiple context managers
in one statement. Context managers are processed from left to right
and each one is treated as beginning a new :keyword:`with` statement.
@ -363,7 +422,10 @@ Some smaller changes made to the core Python language are:
* The :class:`file` object will now set the :attr:`filename` attribute
on the :exc:`IOError` exception when trying to open a directory
on POSIX platforms. (Noted by Jan Kaliszewski; :issue:`4764`.)
on POSIX platforms (noted by Jan Kaliszewski; :issue:`4764`), and
now explicitly checks for and forbids writing to read-only file objects
instead of trusting the C library to catch and report the error
(fixed by Stefan Krah; :issue:`5677`).
* The Python tokenizer now translates line endings itself, so the
:func:`compile` built-in function can now accept code using any
@ -375,6 +437,10 @@ Some smaller changes made to the core Python language are:
Python3-warning mode, Python 2.7 will now warn about this odd usage.
(Noted by James Lingard; :issue:`7362`.)
* When a module object is garbage-collected, the module's dictionary is
now only cleared if no one else is holding a reference to the
dictionary (:issue:`7140`).
.. ======================================================================
@ -498,6 +564,10 @@ changes, or look through the Subversion logs for all the details.
(Contributed by Maru Newby after a suggestion by
Senthil Kumaran; :issue:`5142`.)
* The :mod:`binascii` module now supports the buffer API, so it can be
used with :class:`memoryview` instances and other similar buffer objects.
(Backported from 3.x by Florent Xicluna; :issue:`7703`.)
* The :mod:`bz2` module's :class:`BZ2File` now supports the context
management protocol, so you can write ``with bz2.BZ2File(...) as f: ...``.
(Contributed by Hagen Fuerstenau; :issue:`3860`.)
@ -566,7 +636,10 @@ changes, or look through the Subversion logs for all the details.
* The :mod:`ctypes` module now always converts ``None`` to a C NULL
pointer for arguments declared as pointers. (Changed by Thomas
Heller; :issue:`4606`.)
Heller; :issue:`4606`.) The underlying `libffi library
<http://sourceware.org/libffi/>`__ has been updated to version
3.0.9, containing various fixes for different platforms. (Updated
by Matthias Klose; :issue:`8142`.)
* New method: the :mod:`datetime` module's :class:`timedelta` class
gained a :meth:`total_seconds` method that returns the number of seconds
@ -592,46 +665,6 @@ changes, or look through the Subversion logs for all the details.
left-alignment. This has been changed to right-alignment, which seems
more sensible for numeric types. (Changed by Mark Dickinson; :issue:`6857`.)
* Distutils is being more actively developed, thanks to Tarek Ziadé
who has taken over maintenance of the package, so there are a number
of fixes and improvments.
A new :file:`setup.py` subcommand, ``check``, will check that the
arguments being passed to the :func:`setup` function are complete
and correct (:issue:`5732`).
Byte-compilation by the ``install_lib`` subcommand is now only done
if the ``sys.dont_write_bytecode`` setting allows it (:issue:`7071`).
:func:`distutils.sdist.add_defaults` now uses
*package_dir* and *data_files* to create the MANIFEST file.
:mod:`distutils.sysconfig` now reads the :envvar:`AR` and
:envvar:`ARFLAGS` environment variables.
.. ARFLAGS done in #5941
It is no longer mandatory to store clear-text passwords in the
:file:`.pypirc` file when registering and uploading packages to PyPI. As long
as the username is present in that file, the :mod:`distutils` package will
prompt for the password if not present. (Added by Tarek Ziadé,
based on an initial contribution by Nathan Van Gheem; :issue:`4394`.)
A Distutils setup can now specify that a C extension is optional by
setting the *optional* option setting to true. If this optional is
supplied, failure to build the extension will not abort the build
process, but instead simply not install the failing extension.
(Contributed by Georg Brandl; :issue:`5583`.)
The :class:`distutils.dist.DistributionMetadata` class'
:meth:`read_pkg_file` method will read the contents of a package's
:file:`PKG-INFO` metadata file. For an example of its use, see
:ref:`reading-metadata`.
(Contributed by Tarek Ziadé; :issue:`7457`.)
:file:`setup.py` files will now accept a :option:`--no-user-cfg` switch
to skip reading the :file:`~/.pydistutils.cfg` file. (Suggested by
by Michael Hoffman, and implemented by Paul Winkler; :issue:`1180`.)
* The :class:`Fraction` class now accepts two rational numbers
as arguments to its constructor.
(Implemented by Mark Dickinson; :issue:`5812`.)
@ -649,9 +682,12 @@ changes, or look through the Subversion logs for all the details.
otherwise. (Contributed by Antoine Pitrou; :issue:`4688`.)
* The :mod:`gzip` module's :class:`GzipFile` now supports the context
management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``.
(Contributed by Hagen Fuerstenau; :issue:`3860`.)
It's now possible to override the modification time
management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``
(contributed by Hagen Fuerstenau; :issue:`3860`), and it now implements
the :class:`io.BufferedIOBase` ABC, so you can wrap it with
:class:`io.BufferedReader` for faster processing
(contributed by Nir Aides; :issue:`7471`).
It's also now possible to override the modification time
recorded in a gzipped file by providing an optional timestamp to
the constructor. (Contributed by Jacques Frechet; :issue:`4272`.)
@ -663,6 +699,11 @@ changes, or look through the Subversion logs for all the details.
supports buffering, resulting in much faster reading of HTTP responses.
(Contributed by Kristjan Valur Jonsson; :issue:`4879`.)
The :class:`HTTPConnection` and :class:`HTTPSConnection` classes
now support a *source_address* parameter, a ``(host, port)`` 2-tuple
giving the source address that will be used for the connection.
(Contributed by Eldon Ziegler; :issue:`3972`.)
* The :mod:`imaplib` module now supports IPv6 addresses.
(Contributed by Derek Morr; :issue:`1655`.)
@ -756,6 +797,10 @@ changes, or look through the Subversion logs for all the details.
contributed by Travis H.; :issue:`6508`. Support for initgroups added
by Jean-Paul Calderone; :issue:`7333`.)
The :func:`os.fork` function now re-initializes the import lock in
the child process; this fixes problems on Solaris when :func:`fork`
is called from a thread. (Fixed by Zsolt Cserna; :issue:`7242`.)
The :func:`normpath` function now preserves Unicode; if its input path
is a Unicode string, the return value is also a Unicode string.
(Fixed by Matt Giuca; :issue:`5827`.)
@ -774,6 +819,10 @@ changes, or look through the Subversion logs for all the details.
named pipes like a regular file by opening them for reading, and
this would block indefinitely. (Fixed by Antoine Pitrou; :issue:`3002`.)
New function: :func:`make_archive` takes a filename, archive type
(zip or tar-format), and a directory path, and creates an archive
containing the directory's contents. (Added by Tarek Ziadé.)
* New functions: in the :mod:`site` module, three new functions
return various site- and user-specific paths.
:func:`getsitepackages` returns a list containing all
@ -785,9 +834,24 @@ changes, or look through the Subversion logs for all the details.
to store data.
(Contributed by Tarek Ziadé; :issue:`6693`.)
The :mod:`site` module now reports exceptions occurring
when the :mod:`sitecustomize` module is imported, and will no longer
catch and swallow the :exc:`KeyboardError` exception. (Fixed by
Victor Stinner; :issue:`3137`.)
* The :mod:`socket` module's :class:`SSL` objects now support the
buffer API, which fixed a test suite failure. (Fixed by Antoine Pitrou;
:issue:`7133`.)
buffer API, which fixed a test suite failure. (Fixed by Antoine
Pitrou; :issue:`7133`.)
The :func:`create_connection` function
gained a *source_address* parameter, a ``(host, port)`` 2-tuple
giving the source address that will be used for the connection.
(Contributed by Eldon Ziegler; :issue:`3972`.)
The :meth:`recv_into` and `recvfrom_into` methods will now write
into objects that support the buffer API, most usefully
the :class:`bytearray` and :class:`memoryview` objects. (Implemented by
Antoine Pitrou; :issue:`8104`.)
* The :mod:`SocketServer` module's :class:`TCPServer` class now
has a :attr:`disable_nagle_algorithm` class attribute.
@ -796,6 +860,13 @@ changes, or look through the Subversion logs for all the details.
prevent buffering many small sends into a single TCP packet.
(Contributed by Kristjan Valur Jonsson; :issue:`6192`.)
* Updated module: the :mod:`sqlite` module has been updated to
version 2.6.0 of the `pysqlite package <http://code.google.com/p/pysqlite/>`__. Version 2.6.0 includes a number of bugfixes, and adds
the ability to load SQLite extensions from shared libraries.
Call the ``enable_load_extension(True)`` method to enable extensions,
and then call :meth:`load_extension` to load a particular shared library.
(Updated by Gerhard Häring.)
* The :mod:`struct` module will no longer silently ignore overflow
errors when a value is too large for a particular integer format
code (one of ``bBhHiIlLqQ``); it now always raises a
@ -852,6 +923,8 @@ changes, or look through the Subversion logs for all the details.
resulting archive. This is more powerful than the existing
*exclude* argument, which has therefore been deprecated.
(Added by Lars Gustäbel; :issue:`6856`.)
The :class:`TarFile` class also now supports the context manager protocol.
(Added by Lars Gustäbel; :issue:`7232`.)
* The :mod:`threading` module's :meth:`Event.wait` method now returns
the internal flag on exit. This means the method will usually
@ -860,9 +933,22 @@ changes, or look through the Subversion logs for all the details.
a timeout was provided and the operation timed out.
(Contributed by Tim Lesher; :issue:`1674032`.)
* The Unicode database provided by the :mod:`unicodedata` module
remains at version 5.1.0, but Python now uses it internally to
determine which characters are numeric, whitespace, or represent
line breaks. The database also now includes information from the
:file:`Unihan.txt` data file. (Patch by Anders Chrigström
and Amaury Forgeot d'Arc; :issue:`1571184`.)
* The :class:`UserDict` class is now a new-style class. (Changed by
Benjamin Peterson.)
* The ElementTree library, :mod:`xml.etree`, no longer escapes
ampersands and angle brackets when outputting an XML processing
instruction (which looks like `<?xml-stylesheet href="#style1"?>`)
or comment (which looks like `<!-- comment -->`).
(Patch by Neil Muller; :issue:`2746`.)
* The :mod:`zipfile` module's :class:`ZipFile` now supports the context
management protocol, so you can write ``with zipfile.ZipFile(...) as f: ...``.
(Contributed by Brian Curtin; :issue:`5511`.)
@ -877,18 +963,81 @@ changes, or look through the Subversion logs for all the details.
accepts a file object, in addition to the path names accepted in earlier
versions. (Contributed by Gabriel Genellina; :issue:`4756`.)
The :meth:`writestr` method now has an optional *compress_type* parameter
that lets you override the default compression method specified in the
:class:`ZipFile` constructor. (Contributed by Ronald Oussoren;
:issue:`6003`.)
* XXX the :mod:`shutil` module has now a :func:`make_archive` function
(see the module doc, contributed by Tarek)
(see the module doc, contributed by Tarek)
New module: sysconfig
---------------------------------
XXX A new :mod:`sysconfig` module has been extracted from
:mod:`distutils` and put in the standard library.
The :mod:`sysconfig` module provides access to Python's configuration
information like the list of installation paths and the configuration
variables relevant for the current platform. (contributed by Tarek)
Updated module: ElementTree 1.3
---------------------------------
XXX write this.
.. ======================================================================
.. whole new modules get described in subsections here
* XXX A new :mod:`sysconfig` module has been extracted from :mod:`distutils`
and put in the standard library.
The :mod:`sysconfig` module provides access to Python's configuration
information like the list of installation paths and the configuration
variables relevant for the current platform.
Distutils Enhancements
---------------------------------
Distutils is being more actively developed, thanks to Tarek Ziadé
who has taken over maintenance of the package, so there are a number
of fixes and improvements.
A new :file:`setup.py` subcommand, ``check``, will check that the
arguments being passed to the :func:`setup` function are complete
and correct (:issue:`5732`).
Byte-compilation by the ``install_lib`` subcommand is now only done
if the ``sys.dont_write_bytecode`` setting allows it (:issue:`7071`).
:func:`distutils.sdist.add_defaults` now uses
*package_dir* and *data_files* to create the MANIFEST file.
:mod:`distutils.sysconfig` now reads the :envvar:`AR` and
:envvar:`ARFLAGS` environment variables.
.. ARFLAGS done in #5941
It is no longer mandatory to store clear-text passwords in the
:file:`.pypirc` file when registering and uploading packages to PyPI. As long
as the username is present in that file, the :mod:`distutils` package will
prompt for the password if not present. (Added by Tarek Ziadé,
based on an initial contribution by Nathan Van Gheem; :issue:`4394`.)
A Distutils setup can now specify that a C extension is optional by
setting the *optional* option setting to true. If this optional is
supplied, failure to build the extension will not abort the build
process, but instead simply not install the failing extension.
(Contributed by Georg Brandl; :issue:`5583`.)
The :class:`distutils.dist.DistributionMetadata` class'
:meth:`read_pkg_file` method will read the contents of a package's
:file:`PKG-INFO` metadata file. For an example of its use, see
:ref:`reading-metadata`.
(Contributed by Tarek Ziadé; :issue:`7457`.)
:file:`setup.py` files will now accept a :option:`--no-user-cfg` switch
to skip reading the :file:`~/.pydistutils.cfg` file. (Suggested by
by Michael Hoffman, and implemented by Paul Winkler; :issue:`1180`.)
When creating a tar-format archive, the ``sdist`` subcommand now
allows specifying the user id and group that will own the files in the
archives using the :option:`--owner` and :option:`--group` switches
(:issue:`6516`).
Unit Testing Enhancements
@ -948,7 +1097,8 @@ GvR worked on merging them into Python's version of :mod:`unittest`.
* :meth:`assertMultiLineEqual` compares two strings, and if they're
not equal, displays a helpful comparison that highlights the
differences in the two strings.
differences in the two strings. This comparison is now used by
default when Unicode strings are compared with :meth:`assertEqual`.)
* :meth:`assertRegexpMatches` checks whether its first argument is a
string matching a regular expression provided as its second argument.
@ -967,18 +1117,22 @@ GvR worked on merging them into Python's version of :mod:`unittest`.
only reports the differences between the sets in case of error.
* Similarly, :meth:`assertListEqual` and :meth:`assertTupleEqual`
compare the specified types and explain the differences.
compare the specified types and explain any differences without necessarily
printing their full values; these methods are now used by default
when comparing lists and tuples using :meth:`assertEqual`.
More generally, :meth:`assertSequenceEqual` compares two sequences
and can optionally check whether both sequences are of a
particular type.
* :meth:`assertDictEqual` compares two dictionaries and reports the
differences. :meth:`assertDictContainsSubset` checks whether
differences; it's now used by default when you compare two dictionaries
using :meth:`assertEqual`. :meth:`assertDictContainsSubset` checks whether
all of the key/value pairs in *first* are found in *second*.
* :meth:`assertAlmostEqual` and :meth:`assertNotAlmostEqual` short-circuit
(automatically pass or fail without checking decimal places) if the objects
are equal.
* :meth:`assertAlmostEqual` and :meth:`assertNotAlmostEqual` test
whether *first* and *second* are approximately equal by computing
their difference, rounding the result to an optionally-specified number
of *places* (the default is 7), and comparing to zero.
* :meth:`loadTestsFromName` properly honors the ``suiteClass`` attribute of
the :class:`TestLoader`. (Fixed by Mark Roddy; :issue:`6866`.)
@ -1232,6 +1386,14 @@ Port-Specific Changes: Mac OS X
Other Changes and Fixes
=======================
* Two benchmark scripts, :file:`iobench` and :file:`ccbench`, were
added to the :file:`Tools` directory. :file:`iobench` measures the
speed of built-in file I/O objects (as returned by :func:`open`)
while performing various operations, and :file:`ccbench` is a
concurrency benchmark that tries to measure computing throughput,
thread switching latency, and IO processing bandwidth when
performing several tasks using a varying number of threads.
* When importing a module from a :file:`.pyc` or :file:`.pyo` file
with an existing :file:`.py` counterpart, the :attr:`co_filename`
attributes of the resulting code objects are overwritten when the
@ -1283,6 +1445,14 @@ that may require changes to your code:
nothing when a negative length is requested, as other file-like
objects do. (:issue:`7348`).
In the standard library:
* The ElementTree library, :mod:`xml.etree`, no longer escapes
ampersands and angle brackets when outputting an XML processing
instruction (which looks like `<?xml-stylesheet href="#style1"?>`)
or comment (which looks like `<!-- comment -->`).
(Patch by Neil Muller; :issue:`2746`.)
For C extensions:
* C extensions that use integer format codes with the ``PyArg_Parse*``