Add various items
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Andrew M. Kuchling
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@ -73,6 +73,11 @@ A partial list of 3.1 features that were backported to 2.7:
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* The new format specifier described in :ref:`pep-0378`.
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* The :class:`memoryview` object.
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* A small subset of the :mod:`importlib` module `described below <#importlib-section>`__.
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* Float-to-string and string-to-float conversions now round their
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results more correctly. And :func:`repr` of a floating-point
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number *x* returns a result that's guaranteed to round back to the
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same number when converted back to a string.
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* The :cfunc:`PyLong_AsLongAndOverflow` C API function.
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One porting change: the :option:`-3` switch now automatically
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enables the :option:`-Qwarn` switch that causes warnings
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@ -237,6 +242,33 @@ Some smaller changes made to the core Python language are:
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(Proposed in http://codereview.appspot.com/53094; implemented by
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Georg Brandl.)
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* Conversions between floating-point numbers and strings are
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now correctly rounded on most platforms. These conversions occur
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in many different places: :func:`str` on
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floats and complex numbers; the :class:`float` and :class:`complex`
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constructors;
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numeric formatting; serialization and
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deserialization of floats and complex numbers using the
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:mod:`marshal`, :mod:`pickle`
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and :mod:`json` modules;
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parsing of float and imaginary literals in Python code;
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and :class:`Decimal`-to-float conversion.
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Related to this, the :func:`repr` of a floating-point number *x*
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now returns a result based on the shortest decimal string that's
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guaranteed to round back to *x* under correct rounding (with
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round-half-to-even rounding mode). Previously it gave a string
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based on rounding x to 17 decimal digits.
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The rounding library responsible for this improvement works on
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Windows, and on Unix platforms using the gcc, icc, or suncc
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compilers. There may be a small number of platforms where correct
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operation of this code cannot be guaranteed, so the code is not
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used on such systems.
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Implemented by Mark Dickinson, using David Gay's :file:`dtoa.c` library;
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:issue:`7117`.
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* The :meth:`str.format` method now supports automatic numbering of the replacement
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fields. This makes using :meth:`str.format` more closely resemble using
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``%s`` formatting::
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@ -259,6 +291,10 @@ Some smaller changes made to the core Python language are:
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alignment is applied to the whole of the resulting ``1.5+3j``
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output. (Contributed by Eric Smith; :issue:`1588`.)
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The 'F' format code now always formats its output using uppercase characters,
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so it will now produce 'INF' and 'NAN'.
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(Contributed by Eric Smith; :issue:`3382`.)
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* The :func:`int` and :func:`long` types gained a ``bit_length``
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method that returns the number of bits necessary to represent
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its argument in binary::
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@ -318,6 +354,10 @@ Some smaller changes made to the core Python language are:
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supported. (Contributed by Alexander Belchenko and Amaury Forgeot
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d'Arc; :issue:`1616979`.)
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* The :class:`file` object will now set the :attr:`filename` attribute
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on the :exc:`IOError` exception when trying to open a directory
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on POSIX platforms. (Noted by Jan Kaliszewski; :issue:`4764`.)
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* Extra parentheses in function definitions are illegal in Python 3.x,
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meaning that you get a syntax error from ``def f((x)): pass``. In
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Python3-warning mode, Python 2.7 will now warn about this odd usage.
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@ -499,10 +539,18 @@ changes, or look through the Subversion logs for all the details.
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:meth:`reverse` method that reverses the elements of the deque in-place.
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(Added by Raymond Hettinger.)
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* The :mod:`copy` module's :func:`deepcopy` function will now
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correctly copy bound instance methods. (Implemented by
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Robert Collins; :issue:`1515`.)
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* The :mod:`ctypes` module now always converts ``None`` to a C NULL
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pointer for arguments declared as pointers. (Changed by Thomas
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Heller; :issue:`4606`.)
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* New method: the :mod:`datetime` module's :class:`timedelta` class
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gained a :meth:`total_seconds` method that returns the number of seconds
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in the duration. (Contributed by Brian Quinlan; :issue:`5788`.)
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* New method: the :class:`Decimal` class gained a
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:meth:`from_float` class method that performs an exact conversion
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of a floating-point number to a :class:`Decimal`.
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@ -550,7 +598,7 @@ changes, or look through the Subversion logs for all the details.
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The :class:`distutils.dist.DistributionMetadata` class'
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:meth:`read_pkg_file` method will read the contents of a package's
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metadata file. For an example of its use,
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:file:`PKG-INFO` metadata file. For an example of its use,
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XXX link to file:///MacDev/svn.python.org/python-trunk/Doc/build/html/distutils/examples.html#reading-the-metadata
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(Contributed by Tarek Ziade; :issue:`7457`.)
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@ -667,8 +715,10 @@ changes, or look through the Subversion logs for all the details.
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calls: :func:`getresgid` and :func:`getresuid`, which return the
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real, effective, and saved GIDs and UIDs;
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:func:`setresgid` and :func:`setresuid`, which set
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real, effective, and saved GIDs and UIDs to new values. (Contributed
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by Travis H.; :issue:`6508`.)
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real, effective, and saved GIDs and UIDs to new values;
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:func:`initgroups`. (GID/UID functions
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contributed by Travis H.; :issue:`6508`. Support for initgroups added
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by Jean-Paul Calderone; :issue:`7333`.)
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* The :mod:`pydoc` module now has help for the various symbols that Python
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uses. You can now do ``help('<<')`` or ``help('@')``, for example.
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@ -970,6 +1020,11 @@ Changes to Python's build process and to the C API include:
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instruction currently executing, and then look up the line number
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corresponding to that address. (Added by Jeffrey Yasskin.)
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* New function: :cfunc:`PyLong_AsLongAndOverflow` approximates a Python long
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integer as a C :ctype:`long`. If the number is too large to fit into
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a :ctype:`long`, an *overflow* flag is set and returned to the caller.
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(Contributed by Case Van Horsen; :issue:`7528`.)
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* New macros: the Python header files now define the following macros:
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:cmacro:`Py_ISALNUM`,
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:cmacro:`Py_ISALPHA`,
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@ -988,6 +1043,12 @@ Changes to Python's build process and to the C API include:
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.. XXX these macros don't seem to be described in the c-api docs.
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* New format codes: the :cfunc:`PyFormat_FromString`,
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:cfunc:`PyFormat_FromStringV`, and :cfunc:`PyErr_Format` now
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accepts ``%lld`` and ``%llu`` format codes for displaying values of
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C's :ctype:`long long` types.
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(Contributed by Mark Dickinson; :issue:`7228`.)
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* The complicated interaction between threads and process forking has
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been changed. Previously, the child process created by
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:func:`os.fork` might fail because the child is created with only a
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@ -1047,6 +1108,10 @@ Port-Specific Changes: Windows
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* The :func:`os.listdir` function now correctly fails
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for an empty path. (Fixed by Hirokazu Yamamoto; :issue:`5913`.)
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* The :mod:`mimelib` module will now read the MIME database from
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the Windows registry when initializing.
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(Patch by Gabriel Genellina; :issue:`4969`.)
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.. ======================================================================
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Port-Specific Changes: Mac OS X
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