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| -rw-r--r-- | Doc/whatsnew/2.6.rst | 161 |
1 files changed, 157 insertions, 4 deletions
diff --git a/Doc/whatsnew/2.6.rst b/Doc/whatsnew/2.6.rst index 28916e8..4aa6f9f 100644 --- a/Doc/whatsnew/2.6.rst +++ b/Doc/whatsnew/2.6.rst @@ -72,8 +72,6 @@ new feature. Python 3.0 ================ -.. % XXX add general comment about Python 3.0 features in 2.6 - The development cycle for Python 2.6 also saw the release of the first alphas of Python 3.0, and the development of 3.0 has influenced a number of features in 2.6. @@ -95,7 +93,9 @@ are: A new command-line switch, :option:`-3`, enables warnings about features that will be removed in Python 3.0. You can run code with this switch to see how much work will be necessary to port -code to 3.0. +code to 3.0. The value of this switch is available +to Python code as the boolean variable ``sys.py3kwarning``, +and to C extension code as :cdata:`Py_Py3kWarningFlag`. .. seealso:: @@ -103,6 +103,62 @@ code to 3.0. Python 3.0 and various features that have been accepted, rejected, or are still under consideration. + +Development Changes +================================================== + +While 2.6 was being developed, the Python development process +underwent two significant changes: the developer group +switched from SourceForge's issue tracker to a customized +Roundup installation, and the documentation was converted from +LaTeX to reStructured Text. + + +New Issue Tracker: Roundup +-------------------------------------------------- + +XXX write this. + + +New Documentation Format: ReStructured Text +-------------------------------------------------- + +Python's documentation had been written using LaTeX since the +project's inception around 1989. At that time, most documentation was +printed out for later study, not viewed online. LaTeX was widely used +because it provided attractive printed output while +remaining straightforward to write, once the basic rules +of the markup have been learned. + +LaTeX is still used today for writing technical publications destined +for printing, but the landscape for programming tools has shifted. We +no longer print out reams of documentation; instead, we browse through +it online and HTML is the most important format to support. +Unfortunately, converting LaTeX to HTML is fairly complicated, and +Fred L. Drake Jr., the Python documentation editor for many years, +spent a lot of time wrestling the conversion process into shape. +Occasionally people would suggest converting the documentation into +SGML or, later, XML, but performing a good conversion is a major task +and no one pursued the task to completion. + +During the 2.6 development cycle, Georg Brandl put a substantial +effort into building a new toolchain called Sphinx +for processing the documentation. +The input format is reStructured Text, +a markup commonly used in the Python community that supports +custom extensions and directives. Sphinx concentrates +on its HTML output, producing attractively styled +and modern HTML. (XXX finish this -- mention new search feature) + +.. seealso:: + + `Docutils <http://docutils.sf.net>`__: The fundamental + reStructured Text parser and toolset. + + `Documenting Python <XXX>`__: Describes how to write for + Python's documentation. + + PEP 343: The 'with' statement ============================= @@ -352,6 +408,24 @@ bound to a variable, and calls ``object.close`` at the end of the block. :: .. % ====================================================================== +.. _pep-0366: + +PEP 366: Explicit Relative Imports From a Main Module +============================================================ + +Python's :option:`-m` switch allows running a module as a script. +When you ran a module that was located inside a package, relative +imports didn't work correctly. + +The fix in Python 2.6 adds a :attr:`__package__` attribute to modules. +When present, relative imports will be relative to the value of this +attribute instead of the :attr:`__name__` attribute. PEP 302-style +importers can then set :attr:`__package__`. The :mod:`runpy` module +that implements the :option:`-m` switch now does this, so relative imports +can now be used in scripts running from inside a package. + +.. % ====================================================================== + .. _pep-3110: PEP 3110: Exception-Handling Changes @@ -414,7 +488,7 @@ XXX :pep:`3119` - Introducing Abstract Base Classes PEP written by Guido van Rossum and Talin. Implemented by XXX. - Backported to 2.6 by Benjamin Aranguren (with Alex Martelli). + Backported to 2.6 by Benjamin Aranguren, with Alex Martelli. Other Language Changes ====================== @@ -443,6 +517,25 @@ Here are all of the changes that Python 2.6 makes to the core Python language. .. % Revision 57619 +* Properties now have two attributes, + :attr:`setter` and :attr:`deleter`, that are useful shortcuts for + adding a setter or deleter function to an existing property. + You would use them like this:: + + class C(object): + @property + def x(self): + return self._x + + @x.setter + def x(self, value): + self._x = value + + @x.deleter + def x(self): + del self._x + + * C functions and methods that use :cfunc:`PyComplex_AsCComplex` will now accept arguments that have a :meth:`__complex__` method. In particular, the functions in the @@ -452,11 +545,26 @@ Here are all of the changes that Python 2.6 makes to the core Python language. .. % Patch #1675423 + A numerical nicety: when creating a complex number from two floats + on systems that support signed zeros (-0 and +0), the + :func:`complex()` constructor will now preserve the sign + of the zero. + + .. % Patch 1507 + * Changes to the :class:`Exception` interface as dictated by :pep:`352` continue to be made. For 2.6, the :attr:`message` attribute is being deprecated in favor of the :attr:`args` attribute. +* The :exc:`GeneratorExit` exception now subclasses + :exc:`BaseException` instead of :exc:`Exception`. This means + that an exception handler that does ``except Exception:`` + will not inadvertently catch :exc:`GeneratorExit`. + (Contributed by Chad Austin.) + + .. % Patch #1537 + * The :func:`compile` built-in function now accepts keyword arguments as well as positional parameters. (Contributed by Thomas Wouters.) @@ -653,6 +761,20 @@ complete list of changes, or look through the CVS logs for all the details. .. % Patch #1490190 +* The :mod:`new` module has been removed from Python 3.0. + Importing it therefore + triggers a warning message when Python is running in 3.0-warning + mode. + +* New functions in the :mod:`os` module include + ``fchmod(fd, mode)``, ``fchown(fd, uid, gid)``, + and ``lchmod(path, mode)``, on operating systems that support these + functions. :func:`fchmod` and :func:`fchown` let you change the mode + and ownership of an opened file, and :func:`lchmod` changes the mode + of a symlink. + + (Contributed by Georg Brandl and Christian Heimes.) + * The :func:`os.walk` function now has a ``followlinks`` parameter. If set to True, it will follow symlinks pointing to directories and visit the directory's contents. For backward compatibility, the @@ -703,6 +825,15 @@ complete list of changes, or look through the CVS logs for all the details. changed and :const:`UF_APPEND` to indicate that data can only be appended to the file. (Contributed by M. Levinson.) +* The :mod:`random` module's :class:`Random` objects can + now be pickled on a 32-bit system and unpickled on a 64-bit + system, and vice versa. Unfortunately, this change also means + that Python 2.6's :class:`Random` objects can't be unpickled correctly + on earlier versions of Python. + (Contributed by Shawn Ligocki.) + + .. % Issue 1727780 + * The :mod:`rgbimg` module has been removed. * The :mod:`sets` module has been deprecated; it's better to @@ -725,6 +856,17 @@ complete list of changes, or look through the CVS logs for all the details. .. % Patch #957003 +* A new variable in the :mod:`sys` module, + :attr:`float_info`, is a dictionary + containing information about the platform's floating-point support + derived from the :file:`float.h` file. Key/value pairs + in this dictionary include + ``"mant_dig"`` (number of digits in the mantissa), ``"epsilon"`` + (smallest difference between 1.0 and the next largest value + representable), and several others. (Contributed by Christian Heimes.) + + .. % Patch 1534 + * The :mod:`tarfile` module now supports POSIX.1-2001 (pax) and POSIX.1-1988 (ustar) format tarfiles, in addition to the GNU tar format that was already supported. The default format @@ -883,6 +1025,17 @@ Changes to Python's build process and to the C API include: .. % Patch 1551895 +* Several functions return information about the platform's + floating-point support. :cfunc:`PyFloat_GetMax` returns + the maximum representable floating point value, + and :cfunc:`PyFloat_GetMin` returns the minimum + positive value. :cfunc:`PyFloat_GetInfo` returns a dictionary + containing more information from the :file:`float.h` file, such as + ``"mant_dig"`` (number of digits in the mantissa), ``"epsilon"`` + (smallest difference between 1.0 and the next largest value + representable), and several others. + + .. % Issue 1534 .. % ====================================================================== |