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diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst new file mode 100644 index 0000000..fe03def --- /dev/null +++ b/Doc/whatsnew/3.7.rst @@ -0,0 +1,179 @@ +**************************** + What's New In Python 3.7 +**************************** + +:Release: |release| +:Date: |today| + +.. Rules for maintenance: + + * Anyone can add text to this document. Do not spend very much time + on the wording of your changes, because your text will probably + get rewritten to some degree. + + * The maintainer will go through Misc/NEWS periodically and add + changes; it's therefore more important to add your changes to + Misc/NEWS than to this file. + + * This is not a complete list of every single change; completeness + is the purpose of Misc/NEWS. Some changes I consider too small + or esoteric to include. If such a change is added to the text, + I'll just remove it. (This is another reason you shouldn't spend + too much time on writing your addition.) + + * If you want to draw your new text to the attention of the + maintainer, add 'XXX' to the beginning of the paragraph or + section. + + * It's OK to just add a fragmentary note about a change. For + example: "XXX Describe the transmogrify() function added to the + socket module." The maintainer will research the change and + write the necessary text. + + * You can comment out your additions if you like, but it's not + necessary (especially when a final release is some months away). + + * Credit the author of a patch or bugfix. Just the name is + sufficient; the e-mail address isn't necessary. + + * It's helpful to add the bug/patch number as a comment: + + XXX Describe the transmogrify() function added to the socket + module. + (Contributed by P.Y. Developer in :issue:`12345`.) + + This saves the maintainer the effort of going through the Mercurial log + when researching a change. + +This article explains the new features in Python 3.7, compared to 3.6. + +For full details, see the :ref:`changelog <changelog>`. + +.. note:: + + Prerelease users should be aware that this document is currently in draft + form. It will be updated substantially as Python 3.7 moves towards release, + so it's worth checking back even after reading earlier versions. + + +Summary -- Release highlights +============================= + +.. This section singles out the most important changes in Python 3.7. + Brevity is key. + + +.. PEP-sized items next. + + + +New Features +============ + + + +Other Language Changes +====================== + +* More than 255 arguments can now be passed to a function, and a function can + now have more than 255 parameters. + (Contributed by Serhiy Storchaka in :issue:`12844` and :issue:`18896`.) + +* :meth:`bytes.fromhex` and :meth:`bytearray.fromhex` now ignore all ASCII + whitespace, not only spaces. + (Contributed by Robert Xiao in :issue:`28927`.) + + +New Modules +=========== + +* None yet. + + +Improved Modules +================ + +unittest.mock +------------- + +The :const:`~unittest.mock.sentinel` attributes now preserve their identity +when they are :mod:`copied <copy>` or :mod:`pickled <pickle>`. +(Contributed by Serhiy Storchaka in :issue:`20804`.) + + +Optimizations +============= + +* Added two new opcodes: ``LOAD_METHOD`` and ``CALL_METHOD`` to avoid + instantiation of bound method objects for method calls, which results + in method calls being faster up to 20%. + (Contributed by Yury Selivanov and INADA Naoki in :issue:`26110`.) + + +Build and C API Changes +======================= + +* A full copy of libffi is no longer bundled for use when building the + :mod:`_ctypes <ctypes>` module on non-OSX UNIX platforms. An installed copy + of libffi is now required when building ``_ctypes`` on such platforms. + Contributed by Zachary Ware in :issue:`27979`. + +* The fields :c:member:`name` and :c:member:`doc` of structures + :c:type:`PyMemberDef`, :c:type:`PyGetSetDef`, + :c:type:`PyStructSequence_Field`, :c:type:`PyStructSequence_Desc`, + and :c:type:`wrapperbase` are now of type ``const char *`` rather of + ``char *``. (Contributed by Serhiy Storchaka in :issue:`28761`.) + + +Deprecated +========== + + + +Removed +======= + +API and Feature Removals +------------------------ + +* Unknown escapes consisting of ``'\'`` and an ASCII letter in replacement + templates for :func:`re.sub` were deprecated in Python 3.5, and will now + cause an error. + +* Removed support of the *exclude* argument in :meth:`tarfile.TarFile.add`. + It was deprecated in Python 2.7 and 3.2. Use the *filter* argument instead. + +* The ``splitunc()`` function in the :mod:`ntpath` module was deprecated in + Python 3.1, and has now been removed. Use the :func:`~os.path.splitdrive` + function instead. + + +Porting to Python 3.7 +===================== + +This section lists previously described changes and other bugfixes +that may require changes to your code. + + +Changes in the Python API +------------------------- + +* A format string argument for :meth:`string.Formatter.format` + is now :ref:`positional-only <positional-only_parameter>`. + Passing it as a keyword argument was deprecated in Python 3.5. + (Contributed by Serhiy Storchaka in :issue:`29193`.) + +* Attributes :attr:`~http.cookies.Morsel.key`, + :attr:`~http.cookies.Morsel.value` and + :attr:`~http.cookies.Morsel.coded_value` of class + :class:`http.cookies.Morsel` are now read-only. + Assigning to them was deprecated in Python 3.5. + Use the :meth:`~http.cookies.Morsel.set` method for setting them. + (Contributed by Serhiy Storchaka in :issue:`29192`.) + + +CPython bytecode changes +------------------------ + +* Added two new opcodes: :opcode:`LOAD_METHOD`` and :opcode:`CALL_METHOD`. + (Contributed by Yury Selivanov and INADA Naoki in :issue:`26110`.) |