(See :issue:`4617`.)
+* The internal :c:type:`structsequence` tool now creates subclasses of tuple.
+ This means that C generated structures like those returned by :func:`os.stat`,
+ :func:`time.gmtime`, and :func:`sys.version_info` now work like a
+ :term:`named tuple` and are more interoperable with functions and methods that
+ expect a tuple as an argument. The is a big step forward in making the C
+ structures as flexible as their pure Python counterparts.
+
+ (Suggested by Arfrever Frehtes Taifersar Arahesis and implemented
+ by Benjamin Peterson in :issue:`8413`.)
+
+* Warnings are now easier control. An :envvar:`PYTHONWARNINGS` environment
+ variable is now available as an alternative to using ``-W`` at the command
+ line.
+
+ (Suggested by Barry Warsaw and implemented by Philip Jenvey in :issue:`7301`.)
+
* A new warning category, :exc:`ResourceWarning`, has been added. It is
emitted when potential issues with resource consumption or cleanup
are detected. It is silenced by default in normal release builds, but
(Patch submitted by Daniel Urban; :issue:`5867`.)
+contextlib
+----------
+
+There is a new and slightly mind-blowing tool
+:class:`~contextlib.ContextDecorator` that is helpful for creating a
+:term:`context manager` that does double-duty as a function decorator.
+
+As a convenience, this new functionality is used by
+:func:`~contextlib.contextmanager` so that no extra effort is needed to support
+both roles.
+
+The basic idea is that both context managers and function decorators can be used
+for pre-action and post-action wrappers. Context managers wrap a group of
+statements using the :keyword:`with`-statement, and function decorators wrap a
+group of statements enclosed in a function. So, occasionally there is a need to
+write a pre/post action wrapper that can be used in either role.
+
+For example, it is sometimes useful to wrap functions or groups of statements
+with a logger that can track the time of entry and time of exit. Rather than
+writing both a function decorator and a context manager for the task, the
+:func:`~contextlib.contextmanager` provides both capabilities in a single
+definition:
+
+>>> import logging
+>>> logging.basicConfig(level=logging.INFO)
+>>> @contextmanager
+... def track_entry_and_exit():
+... logging.info('Entry')
+... yield
+... logging.info('Exit')
+
+Formerly, this would have only been usable as a context manager:
+
+>>> with track_entry_and_exit():
+... print('Some time consuming activity goes here')
+
+Now, it can be used as a decorator as well:
+
+>>> @track_entry_and_exit
+... def activity():
+... print('Some time consuming activity goes here'
+
+Trying to fulfill two roles at once places some limitations on the technique.
+Context managers normally have the flexibility to return an argument usable by
+the :keyword:`with`-statement, and function decorators can be constructed to
+accept arguments or to know the name of the function they are enclosing. Since
+those features of context managers and function decorators are not overlapping,
+those features are not supported.
+
+In the above example, there is not a clean way for the
+:func:`track_entry_and_exit` decorator to know the name of the enclosed
+function. Likewise, the *track_entry_and_exit* context manager does not have a
+way to return a logging instance for use in the body of enclosed statements.
+
+(Contributed by Michael Foord in :issue:`9110`.)
+
ftp
---
(Patch by Florent Xicluna in :issue:`7622` and :issue:`7462`.)
+
+* String to integer conversions now work two "digits" at a time, reducing the
+ number of division and modulo operations.
+
+ (:issue:`6713` by Gawain Bolton, Mark Dickinson, and Victor Stinner.)
+
There were several other minor optimizations. Set differencing now runs faster
when one operand is much larger than the other (Patch by Andress Bennetts in
:issue:`8685`). The :meth:`array.repeat` method has a faster implementation
``'mbcs'``), and the ``'surrogateescape'`` error handler on all operating
systems.
+* Added the *cp720* Arabic DOS encoding (:issue:`1616979`).
+
Documentation
=============
(Contributed by Amaury Forgeot D'Arc; :issue:`9210`.)
-* Hash values are now values of a new type, Py_hash_t, which is defined to
- be the same size as a pointer. Previously they were of type long, which
- on some 64-bit operating systems is still only 32 bits long. As a result
- of this fix, :class:`set` and :class:`dict` can now hold more than ``2**32``
- entries on builds with 64-bit pointers (previously, they could grow to
- that size but their performance degraded catastrophically).
+* Hash values are now values of a new type, :c:type:`Py_hash_t`, which is
+ defined to be the same size as a pointer. Previously they were of type long,
+ which on some 64-bit operating systems is still only 32 bits long. As a
+ result of this fix, :class:`set` and :class:`dict` can now hold more than
+ ``2**32`` entries on builds with 64-bit pointers (previously, they could grow
+ to that size but their performance degraded catastrophically).
+
+ (Suggested by Raymond Hettinger and implemented by Benjamin Peterson;
+ :issue:`9778`.)
+
+* A new macro :c:macro:`Py_VA_COPY` copies the state of the variable argument
+ list. It is equivalent to C99 *va_copy* but available on all python platforms
+ (:issue:`2443`).
+
+* A new C API function :c:func:`PySys_SetArgvEx` allows an embeddered
+ interpreter to set sys.argv without also modifying :attr:`sys.path`
+ (:issue:`5753`).
+
+* :c:macro:`PyEval_CallObject` is now only available in macro form. The
+ function declaration, which was kept for backwards compatibility reasons, is
+ now removed -- the macro was introduced in 1997 (:issue:`8276`).
+
+* The is a new function :c:func:`PyLong_AsLongLongAndOverflow` which
+ is analogous to :c:func:`PyLong_AsLongAndOverflow`. The both serve to
+ convert Python :class:`int` into a native fixed-width type while providing
+ detection of cases where the conversion won't fit (:issue:`7767`).
+
+* The :c:func:`PyUnicode_CompareWithASCIIString` now returns *not equal*
+ if the Python string in *NUL* terminated.
+
+* There is a new function :c:func:`PyErr_NewExceptionWithDoc` that is
+ like :c:func:`PyErr_NewException` but allows a docstring to be specified.
+ This lets C exceptions have the same self-documenting capabilities as
+ their pure Python counterparts (:issue:`7033`).
+
+* When compiled with the ``--with-valgrind`` option, the pymalloc
+ allocator will be automatically disabled when running under Valgrind. This
+ gives improved memory leak detection when running under Valgrind, while taking
+ advantage of pymalloc at other times (:issue:`2422`).
+
+* Removed the "O?" format from the *PyArg_Parse* functions. The format is no
+ longer used and it had never been documented (:issue:`8837`).
- (Contributed by Benjamin Peterson; :issue:`9778`.)
+There were a number of other small changes to the C-API. See the
+:file:`Misc/NEWS` file for a complete list.
Porting to Python 3.2
projects / python / commitdiff