mirror of
https://github.com/python/cpython.git
synced 2024-12-04 07:15:09 +08:00
Update whatsnew document to use specific markup for identifiers, thus enabling cross-linking.
This commit is contained in:
Georg Brandl
parent
396ef80f0d
commit
ec17d204f9
@ -79,7 +79,7 @@ and fast errors; it's the subtle behavioral changes in code that
|
||||
remains syntactically valid that trips people up. I'm also omitting
|
||||
changes to rarely used features.)
|
||||
|
||||
* The ``print`` statement has been replaced with a ``print()`` function,
|
||||
* The ``print`` statement has been replaced with a :func:`print` function,
|
||||
with keyword arguments to replace most of the special syntax of the
|
||||
old ``print`` statement (PEP 3105). Examples::
|
||||
|
||||
@ -106,9 +106,9 @@ changes to rarely used features.)
|
||||
|
||||
There are <4294967296> possibilities!
|
||||
|
||||
Notes about the ``print()`` function:
|
||||
Notes about the :func:`print` function:
|
||||
|
||||
* The ``print()`` function doesn't support the "softspace" feature of
|
||||
* The :func:`print` function doesn't support the "softspace" feature of
|
||||
the old ``print`` statement. For example, in Python 2.x,
|
||||
``print "A\n", "B"`` would write ``"A\nB\n"``; but in Python 3.0,
|
||||
``print("A\n", "B")`` writes ``"A\n B\n"``.
|
||||
@ -118,7 +118,7 @@ changes to rarely used features.)
|
||||
``print(x)`` instead!
|
||||
|
||||
* When using the ``2to3`` source-to-source conversion tool, all
|
||||
``print`` statements are autmatically converted to ``print()``
|
||||
``print`` statements are autmatically converted to :func:`print`
|
||||
function calls, so this is mostly a non-issue for larger projects.
|
||||
|
||||
* Python 3.0 uses strings and bytes instead of the Unicode strings and
|
||||
@ -131,19 +131,19 @@ changes to rarely used features.)
|
||||
that if a file is opened using an incorrect mode or encoding, I/O
|
||||
will likely fail.
|
||||
|
||||
* ``map()`` and ``filter()`` return iterators. A quick fix is e.g.
|
||||
* :func:`map` and :func:`filter` return iterators. A quick fix is e.g.
|
||||
``list(map(...))``, but a better fix is often to use a list
|
||||
comprehension (especially when the original code uses ``lambda``).
|
||||
Particularly tricky is ``map()`` invoked for the side effects of the
|
||||
comprehension (especially when the original code uses :keyword:`lambda`).
|
||||
Particularly tricky is :func:`map` invoked for the side effects of the
|
||||
function; the correct transformation is to use a for-loop.
|
||||
|
||||
* ``dict`` methods ``.keys()``, ``.items()`` and ``.values()`` return
|
||||
views instead of lists. For example, this no longer works:
|
||||
``k = d.keys(); k.sort()``. Use ``k = sorted(d)`` instead.
|
||||
* :class:`dict` methods :meth:`dict.keys`, :meth:`dict.items` and
|
||||
:meth:`dict.values` return views instead of lists. For example, this no
|
||||
longer works: ``k = d.keys(); k.sort()``. Use ``k = sorted(d)`` instead.
|
||||
|
||||
* ``1/2`` returns a float. Use ``1//2`` to get the truncating behavior.
|
||||
|
||||
* The ``repr()`` of a long integer doesn't include the trailing ``L``
|
||||
* The :func:`repr` of a long integer doesn't include the trailing ``L``
|
||||
anymore, so code that unconditionally strips that character will
|
||||
chop off the last digit instead.
|
||||
|
||||
@ -151,32 +151,33 @@ changes to rarely used features.)
|
||||
Strings and Bytes
|
||||
=================
|
||||
|
||||
* There is only one string type; its name is ``str`` but its behavior
|
||||
and implementation are more like ``unicode`` in 2.x.
|
||||
* There is only one string type; its name is :class:`str` but its behavior and
|
||||
implementation are like :class:`unicode` in 2.x.
|
||||
|
||||
* The ``basestring`` superclass has been removed. The ``2to3`` tool
|
||||
replaces every occurence of ``basestring`` with ``str``.
|
||||
* The :class:`basestring` superclass has been removed. The ``2to3`` tool
|
||||
replaces every occurence of :class:`basestring` with :class:`str`.
|
||||
|
||||
* PEP 3137: There is a new type, ``bytes``, to represent binary data
|
||||
(and encoded text, which is treated as binary data until you decide
|
||||
to decode it). The ``str`` and ``bytes`` types cannot be mixed; you
|
||||
must always explicitly convert between them, using the ``.encode()``
|
||||
(str -> bytes) or ``.decode()`` (bytes -> str) methods.
|
||||
* PEP 3137: There is a new type, :class:`bytes`, to represent binary data (and
|
||||
encoded text, which is treated as binary data until you decide to decode it).
|
||||
The :class:`str` and :class:`bytes` types cannot be mixed; you must always
|
||||
explicitly convert between them, using the :meth:`str.encode` (str -> bytes)
|
||||
or :meth:`bytes.decode` (bytes -> str) methods.
|
||||
|
||||
* PEP 3112: Bytes literals. E.g. b"abc".
|
||||
.. XXX add bytearray
|
||||
|
||||
* PEP 3112: Bytes literals, e.g. ``b"abc"``, create :class:`bytes` instances.
|
||||
|
||||
* PEP 3120: UTF-8 default source encoding.
|
||||
|
||||
* PEP 3131: Non-ASCII identifiers. (However, the standard library
|
||||
remains ASCII-only with the exception of contributor names in
|
||||
comments.)
|
||||
* PEP 3131: Non-ASCII identifiers. (However, the standard library remains
|
||||
ASCII-only with the exception of contributor names in comments.)
|
||||
|
||||
* PEP 3116: New I/O Implementation. The API is nearly 100% backwards
|
||||
compatible, but completely reimplemented (currently mostly in
|
||||
Python). Also, binary files use bytes instead of strings.
|
||||
compatible, but completely reimplemented (currently mostly in Python). Also,
|
||||
binary files use bytes instead of strings.
|
||||
|
||||
* The ``StringIO`` and ``cStringIO`` modules are gone. Instead,
|
||||
import ``StringIO`` or ``BytesIO`` from the ``io`` module.
|
||||
* The :mod:`StringIO` and :mod:`cStringIO` modules are gone. Instead, import
|
||||
:class:`io.StringIO` or :class:`io.BytesIO`.
|
||||
|
||||
|
||||
PEP 3101: A New Approach to String Formatting
|
||||
@ -184,20 +185,20 @@ PEP 3101: A New Approach to String Formatting
|
||||
|
||||
.. XXX expand this
|
||||
|
||||
* A new system for built-in string formatting operations replaces
|
||||
the ``%`` string formatting operator.
|
||||
* A new system for built-in string formatting operations replaces the ``%``
|
||||
string formatting operator.
|
||||
|
||||
|
||||
PEP 3106: Revamping dict ``.keys()``, ``.items()`` and ``.values()``
|
||||
====================================================================
|
||||
PEP 3106: Revamping dict :meth:`dict.keys`, :meth:`dict.items` and :meth:`dict.values`
|
||||
======================================================================================
|
||||
|
||||
.. XXX expand this
|
||||
|
||||
* The ``.iterkeys()``, ``.itervalues()`` and ``.iteritems()`` methods
|
||||
have been removed.
|
||||
* The :meth:`dict.iterkeys`, :meth:`dict.itervalues` and :meth:`dict.iteritems`
|
||||
methods have been removed.
|
||||
|
||||
* ``.keys()``, ``.values()`` and ``.items()`` return objects with set
|
||||
behavior that reference the underlying dict.
|
||||
* :meth:`dict.keys`, :meth:`dict.values` and :meth:`dict.items` return objects
|
||||
with set behavior that reference the underlying dict.
|
||||
|
||||
|
||||
PEP 3107: Function Annotations
|
||||
@ -205,33 +206,31 @@ PEP 3107: Function Annotations
|
||||
|
||||
.. XXX expand this
|
||||
|
||||
* A standardized way of annotating a function's parameters and return
|
||||
values.
|
||||
* A standardized way of annotating a function's parameters and return values.
|
||||
|
||||
|
||||
Exception Stuff
|
||||
===============
|
||||
|
||||
* PEP 352: Exceptions must derive from BaseException. This is the
|
||||
root of the exception hierarchy.
|
||||
* PEP 352: Exceptions must derive from :exc:`BaseException`. This is the root
|
||||
of the exception hierarchy.
|
||||
|
||||
* StandardException was removed (already in 2.6).
|
||||
* :exc:`StandardError` was removed (already in 2.6).
|
||||
|
||||
* Dropping sequence behavior (slicing!) and ``.message`` attribute of
|
||||
* Dropping sequence behavior (slicing!) and :attr:`message` attribute of
|
||||
exception instances.
|
||||
|
||||
* PEP 3109: Raising exceptions. You must now use ``raise
|
||||
Exception(args)`` instead of ``raise Exception, args``.
|
||||
* PEP 3109: Raising exceptions. You must now use ``raise Exception(args)``
|
||||
instead of ``raise Exception, args``.
|
||||
|
||||
* PEP 3110: Catching exceptions.
|
||||
|
||||
* PEP 3134: Exception chaining. (The ``__context__`` feature from the
|
||||
PEP hasn't been implemented yet in 3.0a1.)
|
||||
* PEP 3134: Exception chaining. (The :attr:`__context__` feature from the PEP
|
||||
hasn't been implemented yet in 3.0a2.)
|
||||
|
||||
* A few exception messages are improved when Windows fails to load an
|
||||
extension module. For example, ``error code 193`` is now ``%1 is not
|
||||
a valid Win32 application``. Strings now deal with non-English
|
||||
locales.
|
||||
* A few exception messages are improved when Windows fails to load an extension
|
||||
module. For example, ``error code 193`` is now ``%1 is not a valid Win32
|
||||
application``. Strings now deal with non-English locales.
|
||||
|
||||
|
||||
New Class and Metaclass Stuff
|
||||
@ -255,101 +254,97 @@ Other Language Changes
|
||||
Here are most of the changes that Python 3.0 makes to the core Python
|
||||
language and built-in functions.
|
||||
|
||||
* Removed backticks (use ``repr()`` instead).
|
||||
* Removed backticks (use :func:`repr` instead).
|
||||
|
||||
* Removed ``<>`` (use ``!=`` instead).
|
||||
|
||||
* ``!=`` now returns the opposite of ``==``, unless ``==`` returns
|
||||
``NotImplemented``.
|
||||
|
||||
* ``as`` and ``with`` are keywords.
|
||||
* :keyword:`as` and :keyword:`with` are keywords.
|
||||
|
||||
* ``True``, ``False``, and ``None`` are keywords.
|
||||
|
||||
* PEP 237: ``long`` renamed to ``int``. That is, there is only one
|
||||
built-in integral type, named ``int``; but it behaves like the old
|
||||
``long`` type, with the exception that the literal suffix ``L`` is
|
||||
neither supported by the parser nor produced by ``repr()`` anymore.
|
||||
``sys.maxint`` was also removed since the int type has no maximum
|
||||
value anymore.
|
||||
* PEP 237: :class:`long` renamed to :class:`int`. That is, there is only one
|
||||
built-in integral type, named :class:`int`; but it behaves like the old
|
||||
:class:`long` type, with the exception that the literal suffix ``L`` is
|
||||
neither supported by the parser nor produced by :func:`repr` anymore.
|
||||
:data:`sys.maxint` was also removed since the int type has no maximum value
|
||||
anymore.
|
||||
|
||||
* PEP 238: int division returns a float.
|
||||
|
||||
* The ordering operators behave differently: for example, ``x < y``
|
||||
where ``x`` and ``y`` have incompatible types raises ``TypeError``
|
||||
instead of returning a pseudo-random boolean.
|
||||
* The ordering operators behave differently: for example, ``x < y`` where ``x``
|
||||
and ``y`` have incompatible types raises :exc:`TypeError` instead of returning
|
||||
a pseudo-random boolean.
|
||||
|
||||
* ``__getslice__()`` and friends killed. The syntax ``a[i:j]`` now
|
||||
translates to ``a.__getitem__(slice(i, j))`` (or ``__setitem__``
|
||||
or ``__delitem__``, depending on context).
|
||||
* :meth:`__getslice__` and friends killed. The syntax ``a[i:j]`` now translates
|
||||
to ``a.__getitem__(slice(i, j))`` (or :meth:`__setitem__` or
|
||||
:meth:`__delitem__`, depending on context).
|
||||
|
||||
* PEP 3102: Keyword-only arguments. Named parameters occurring after
|
||||
``*args`` in the parameter list *must* be specified using keyword
|
||||
syntax in the call. You can also use a bare ``*`` in the parameter
|
||||
list to indicate that you don't accept a variable-length argument
|
||||
list, but you do have keyword-only arguments.
|
||||
* PEP 3102: Keyword-only arguments. Named parameters occurring after ``*args``
|
||||
in the parameter list *must* be specified using keyword syntax in the call.
|
||||
You can also use a bare ``*`` in the parameter list to indicate that you don't
|
||||
accept a variable-length argument list, but you do have keyword-only
|
||||
arguments.
|
||||
|
||||
* PEP 3104: ``nonlocal`` statement. Using ``nonlocal x`` you can now
|
||||
* PEP 3104: :keyword:`nonlocal` statement. Using ``nonlocal x`` you can now
|
||||
assign directly to a variable in an outer (but non-global) scope.
|
||||
|
||||
* PEP 3111: ``raw_input()`` renamed to ``input()``. That is, the new
|
||||
``input()`` function reads a line from ``sys.stdin`` and returns it
|
||||
with the trailing newline stripped. It raises ``EOFError`` if the
|
||||
input is terminated prematurely. To get the old behavior of
|
||||
``input()``, use ``eval(input())``.
|
||||
* PEP 3111: :func:`raw_input` renamed to :func:`input`. That is, the new
|
||||
:func:`input` function reads a line from :data:`sys.stdin` and returns it with
|
||||
the trailing newline stripped. It raises :exc:`EOFError` if the input is
|
||||
terminated prematurely. To get the old behavior of :func:`input`, use
|
||||
``eval(input())``.
|
||||
|
||||
* ``xrange()`` renamed to ``range()``.
|
||||
* :func:`xrange` renamed to :func:`range`.
|
||||
|
||||
* PEP 3113: Tuple parameter unpacking removed. You can no longer write
|
||||
``def foo(a, (b, c)): ...``. Use ``def foo(a, b_c): b, c = b_c``
|
||||
instead.
|
||||
* PEP 3113: Tuple parameter unpacking removed. You can no longer write ``def
|
||||
foo(a, (b, c)): ...``. Use ``def foo(a, b_c): b, c = b_c`` instead.
|
||||
|
||||
* PEP 3114: ``.next()`` renamed to ``.__next__()``, new builtin
|
||||
``next()`` to call the ``__next__()`` method on an object.
|
||||
* PEP 3114: ``.next()`` renamed to :meth:`__next__`, new builtin :func:`next` to
|
||||
call the :meth:`__next__` method on an object.
|
||||
|
||||
* PEP 3127: New octal literals; binary literals and ``bin()``.
|
||||
Instead of ``0666``, you write ``0o666``. The oct() function is
|
||||
modified accordingly. Also, ``0b1010`` equals 10, and ``bin(10)``
|
||||
returns ``"0b1010"``. ``0666`` is now a ``SyntaxError``.
|
||||
* PEP 3127: New octal literals; binary literals and :func:`bin`. Instead of
|
||||
``0666``, you write ``0o666``. The :func:`oct` function is modified
|
||||
accordingly. Also, ``0b1010`` equals 10, and ``bin(10)`` returns
|
||||
``"0b1010"``. ``0666`` is now a :exc:`SyntaxError`.
|
||||
|
||||
* PEP 3132: Extended Iterable Unpacking. You can now write things
|
||||
like ``a, b, *rest = some_sequence``. And even ``*rest, a =
|
||||
stuff``. The ``rest`` object is always a list; the right-hand
|
||||
side may be any iterable.
|
||||
* PEP 3132: Extended Iterable Unpacking. You can now write things like ``a, b,
|
||||
*rest = some_sequence``. And even ``*rest, a = stuff``. The ``rest`` object
|
||||
is always a list; the right-hand side may be any iterable.
|
||||
|
||||
* PEP 3135: New ``super()``. You can now invoke ``super()`` without
|
||||
arguments and the right class and instance will automatically be
|
||||
chosen. With arguments, its behavior is unchanged.
|
||||
* PEP 3135: New :func:`super`. You can now invoke :func:`super` without
|
||||
arguments and the right class and instance will automatically be chosen. With
|
||||
arguments, its behavior is unchanged.
|
||||
|
||||
* ``zip()``, ``map()`` and ``filter()`` return iterators.
|
||||
* :func:`zip`, :func:`map` and :func:`filter` return iterators.
|
||||
|
||||
* ``string.letters`` and its friends (``.lowercase`` and
|
||||
``.uppercase``) are gone. Use ``string.ascii_letters``
|
||||
* :data:`string.letters` and its friends (:data:`string.lowercase` and
|
||||
:data:`string.uppercase`) are gone. Use :data:`string.ascii_letters`
|
||||
etc. instead.
|
||||
|
||||
* Removed: ``apply()``, ``callable()``, ``coerce()``, ``execfile()``,
|
||||
``file()``, ``reduce()``, ``reload()``.
|
||||
* Removed: :func:`apply`, :func:`callable`, :func:`coerce`, :func:`execfile`,
|
||||
:func:`file`, :func:`reduce`, :func:`reload`.
|
||||
|
||||
* Removed: ``dict.has_key()``.
|
||||
* Removed: :meth:`dict.has_key`.
|
||||
|
||||
* ``exec`` is now a function.
|
||||
* :func:`exec` is now a function.
|
||||
|
||||
* There is a new free format floating point representation, which is
|
||||
based on "Floating-Point Printer Sample Code", by Robert G. Burger.
|
||||
``repr(11./5)`` now returns ``2.2`` instead of ``2.2000000000000002``.
|
||||
* There is a new free format floating point representation, which is based on
|
||||
"Floating-Point Printer Sample Code", by Robert G. Burger. ``repr(11./5)``
|
||||
now returns ``2.2`` instead of ``2.2000000000000002``.
|
||||
|
||||
* The ``__oct__()`` and ``__hex__()`` special methods are removed --
|
||||
``oct()`` and ``hex()`` use ``__index__()`` now to convert the
|
||||
argument to an integer.
|
||||
* The :meth:`__oct__` and :meth:`__hex__` special methods are removed --
|
||||
:func:`oct` and :func:`hex` use :meth:`__index__` now to convert the argument
|
||||
to an integer.
|
||||
|
||||
* There is now a ``bin()`` builtin function.
|
||||
* Support is removed for :attr:`__members__` and :attr:`__methods__`.
|
||||
|
||||
* Support is removed for ``__members__`` and ``__methods__``.
|
||||
* Renamed the boolean conversion C-level slot and method: ``nb_nonzero`` is now
|
||||
``nb_bool`` and :meth:`__nonzero__` is now :meth:`__bool__`.
|
||||
|
||||
* ``nb_nonzero`` is now ``nb_bool`` and ``__nonzero__`` is now
|
||||
``__bool__``.
|
||||
|
||||
* Removed ``sys.maxint``. Use ``sys.maxsize``.
|
||||
* Removed :data:`sys.maxint`. Use :data:`sys.maxsize`.
|
||||
|
||||
|
||||
.. ======================================================================
|
||||
@ -360,10 +355,10 @@ Optimizations
|
||||
|
||||
* Detailed changes are listed here.
|
||||
|
||||
The net result of the 3.0 generalizations is that Python 3.0 runs the
|
||||
pystone benchmark around 33% slower than Python 2.5. There's room for
|
||||
improvement; we expect to be optimizing string and integer operations
|
||||
significantly before the final 3.0 release!
|
||||
The net result of the 3.0 generalizations is that Python 3.0 runs the pystone
|
||||
benchmark around 33% slower than Python 2.5. There's room for improvement; we
|
||||
expect to be optimizing string and integer operations significantly before the
|
||||
final 3.0 release!
|
||||
|
||||
.. ======================================================================
|
||||
|
||||
@ -371,26 +366,27 @@ significantly before the final 3.0 release!
|
||||
New, Improved, and Deprecated Modules
|
||||
=====================================
|
||||
|
||||
As usual, Python's standard library received a number of enhancements
|
||||
and bug fixes. Here's a partial list of the most notable changes,
|
||||
sorted alphabetically by module name. Consult the :file:`Misc/NEWS`
|
||||
file in the source tree for a more complete list of changes, or look
|
||||
through the Subversion logs for all the details.
|
||||
As usual, Python's standard library received a number of enhancements and bug
|
||||
fixes. Here's a partial list of the most notable changes, sorted alphabetically
|
||||
by module name. Consult the :file:`Misc/NEWS` file in the source tree for a more
|
||||
complete list of changes, or look through the Subversion logs for all the
|
||||
details.
|
||||
|
||||
* The ``cPickle`` module is gone. Use ``pickle`` instead. Eventually
|
||||
* The :mod:`cPickle` module is gone. Use :mod:`pickle` instead. Eventually
|
||||
we'll have a transparent accelerator module.
|
||||
|
||||
* The ``imageop`` module is gone.
|
||||
* The :mod:`imageop` module is gone.
|
||||
|
||||
* The ``audiodev``, ``Bastion``, ``bsddb185``, ``exceptions``,
|
||||
``linuxaudiodev``, ``md5``, ``MimeWriter``, ``mimify``, ``popen2``,
|
||||
``rexec``, ``sets``, ``sha``, ``stringold``, ``strop``, ``sunaudiodev``,
|
||||
``timing``, and ``xmllib`` modules are gone.
|
||||
* The :mod:`audiodev`, :mod:`Bastion`, :mod:`bsddb185`, :mod:`exceptions`,
|
||||
:mod:`linuxaudiodev`, :mod:`md5`, :mod:`MimeWriter`, :mod:`mimify`,
|
||||
:mod:`popen2`, :mod:`rexec`, :mod:`sets`, :mod:`sha`, :mod:`stringold`,
|
||||
:mod:`strop`, :mod:`sunaudiodev`, :mod:`timing`, and :mod:`xmllib` modules are
|
||||
gone.
|
||||
|
||||
* The ``new`` module is gone.
|
||||
* The :mod:`new` module is gone.
|
||||
|
||||
* The methods ``os.tmpnam()``, ``os.tempnam()`` and ``os.tmpfile()`` have
|
||||
been removed in favor of the ``tempfile`` module.
|
||||
* The functions :func:`os.tmpnam`, :func:`os.tempnam` and :func:`os.tmpfile`
|
||||
have been removed in favor of the :mod:`tempfile` module.
|
||||
|
||||
.. ======================================================================
|
||||
.. whole new modules get described in subsections here
|
||||
@ -407,15 +403,15 @@ Changes to Python's build process and to the C API include:
|
||||
|
||||
* PEP 3121: Extension Module Initialization & Finalization.
|
||||
|
||||
* PEP 3123: Making ``PyObject_HEAD`` conform to standard C.
|
||||
* PEP 3123: Making :cmacro:`PyObject_HEAD` conform to standard C.
|
||||
|
||||
* No more C API support for restricted execution.
|
||||
|
||||
* ``PyNumber_Coerce()``, ``PyNumber_CoerceEx()``, ``PyMember_Get``,
|
||||
and ``PyMember_Set`` C APIs are removed.
|
||||
* :cfunc:`PyNumber_Coerce`, :cfunc:`PyNumber_CoerceEx`, :cfunc:`PyMember_Get`,
|
||||
and :cfunc:`PyMember_Set` C APIs are removed.
|
||||
|
||||
* New C API ``PyImport_ImportModuleNoBlock()``, works like
|
||||
``PyImport_ImportModule()`` but won't block on the import lock (returning
|
||||
* New C API :cfunc:`PyImport_ImportModuleNoBlock`, works like
|
||||
:cfunc:`PyImport_ImportModule` but won't block on the import lock (returning
|
||||
an error instead).
|
||||
|
||||
.. ======================================================================
|
||||
|
||||
Loading…
Reference in New Issue
Block a user