发布于 2015-08-10 00:02:26 | 429 次阅读 | 评论: 0 | 来源: 网友投递
Cython Python的C语言扩展
准确说Cython是单独的一门语言，专门用来写在Python里面import用的扩展库。实际上Cython的语法基本上跟Python一致，而 Cython有专门的“编译器”先将 Cython代码转变成C（自动加入了一大堆的C-Python API），然后使用C编译器编译出最终的Python可调用的模块。
Cython 0.23 发布，此版本相比第二个测试版本改进很小，还有一些 bug 修复。
https://pypi.python.org/pypi/Cython/0.23
此版本是个重要的特性版本，值得关注的改进如下：
* PEP 492 (async/await) 和 PEP 448 (star-unpacking generalizations)
* 内联生长器表达式
* 支持 C++ 分配和 bool() 操作符
* 支持覆盖分析
强烈建议更新，下载：
http://cython.org/
http://cython.org/release/Cython-0.23.tar.gz
http://cython.org/release/Cython-0.23.zip
SHA1 sums:
5a49123b39d89a20fb88bdc7886210
c39cdff695 Cython-0.23.tar.gz
9bec6c6df861be49ed608a0ab688b67bba543abe Cython-0.23.zip
0.23 (2015-08-08)
=================
新特性
--------------
* PEP 492 (async/await) was implemented.
See https://www.python.org/dev/peps/pep-0492/
* PEP 448 (Additional Unpacking Generalizations) was implemented.
See https://www.python.org/dev/peps/pep-0448/
* Support for coverage.py 4.0+ can be enabled by adding the plugin
"Cython.Coverage" to the ".coveragerc" config file.
* Annotated HTML source pages can integrate (XML) coverage reports.
* Tracing is supported in ``nogil`` functions/sections and module init
code.
* When generators are used in a Cython module and the module imports the
modules "inspect" and/or "asyncio", Cython enables interoperability by
patching these modules during the import to recognise Cython's internal
generator and coroutine types. This can be disabled by C compiling the
module with "-D CYTHON_PATCH_ASYNCIO=0" or "-D CYTHON_PATCH_INSPECT=0"
* When generators or coroutines are used in a Cython module, their types
are registered with the ``Generator`` and ``Coroutine`` ABCs in the
``collections`` or ``collections.abc`` stdlib module at import time to
enable interoperability with code that needs to detect and process Python
generators/coroutines. These ABCs were added in CPython 3.5 and are
available for older Python versions through the ``backports_abc`` module
on PyPI. See https://bugs.python.org/issue24018
* Adding/subtracting/dividing/modulus and equality comparisons with
constant Python floats and small integers are faster.
* Binary and/or/xor/rshift operations with small constant Python integers
are faster.
* When called on generator expressions, the builtins ``all()``, ``any()``,
``dict()``, ``list()``, ``set()``, ``sorted()`` and ``unicode.join()``
avoid the generator iteration overhead by inlining a part of their
functionality into the for-loop.
* Keyword argument dicts are no longer copied on function entry when they
are not being used or only passed through to other function calls (e.g.
in wrapper functions).
* The ``PyTypeObject`` declaration in ``cpython.object`` was extended.
* The builtin ``type`` type is now declared as PyTypeObject in source,
allowing for extern functions taking type parameters to have the correct
C signatures. Note that this might break code that uses ``type`` just
for passing around Python types in typed variables. Removing the type
declaration provides a backwards compatible fix.
* ``wraparound()`` and ``boundscheck()`` are available as no-ops in pure
Python mode.
* Const iterators were added to the provided C++ STL declarations.
* Smart pointers were added to the provided C++ STL declarations.
Patch by Daniel Filonik.
* ``NULL`` is allowed as default argument when embedding signatures.
This fixes ticket 843.
* When compiling with ``--embed``, the internal module name is changed to
``__main__`` to allow arbitrary program names, including those that would
be invalid for modules. Note that this prevents reuse of the generated
C code as an importable module.
* External C++ classes that overload the assignment operator can be used.
Patch by Ian Henriksen.
* Support operator bool() for C++ classes so they can be used in
if-statements.
Bugs 修复
----------
* Calling "yield from" from Python on a Cython generator that returned a
value triggered a crash in CPython. This is now being worked around.
See https://bugs.python.org/issue23996
* Language level 3 did not enable true division (a.k.a. float division)
for integer operands.
* Functions with fused argument types that included a generic 'object'
fallback could end up using that fallback also for other explicitly
listed object types.
* Relative cimports could accidentally fall back to trying an absolute
cimport on failure.
* The result of calling a C struct constructor no longer requires an
intermediate assignment when coercing to a Python dict.
* C++ exception declarations with mapping functions could fail to compile
when pre-declared in .pxd files.
* ``cpdef void`` methods are now permitted.
* ``abs(cint)`` could fail to compile in MSVC and used sub-optimal code
in C++. Patch by David Vierra, original patch by Michael Enßlin.
* Buffer index calculations using index variables with small C integer
types could overflow for large buffer sizes.
Original patch by David Vierra.
* C unions use a saner way to coerce from and to Python dicts.
* When compiling a module ``foo.pyx``, the directories in ``sys.path``
are no longer searched when looking for ``foo.pxd``.
Patch by Jeroen Demeyer.
* Memory leaks in the embedding main function were fixed.
Original patch by Michael Enßlin.
* Some complex Python expressions could fail to compile inside of finally
clauses.
* Unprefixed 'str' literals were not supported as C varargs arguments.
* Fixed type errors in conversion enum types to/from Python. Note that
this imposes stricter correctness requirements on enum declarations.
其他改进
-------------
* Changed mangling scheme in header files generated by ``cdef api``
declarations.
* Installation under CPython 3.3+ no longer requires a pass of the
2to3 tool. This also makes it possible to run Cython in Python
3.3+ from a source checkout without installing it first.
Patch by Petr Viktorin.
* ``jedi-typer.py`` (in ``Tools/``) was extended and renamed to
``jedityper.py`` (to make it importable) and now works with and
requires Jedi 0.9. Patch by Tzer-jen Wei.
更多内容请看发行说明。
准确说Cython是单独的一门语言，专门用来写在Python里面import用的扩展库。实际上Cython的语法基本上跟Python一致，而 Cython有专门的“编译器”先将 Cython代码转变成C（自动加入了一大堆的C-Python API），然后使用C编译器编译出最终的Python可调用的模块。