| What's New in Python 2.3 alpha 1? |
| XXX Release date: DD-MMM-2002 XXX |
| ================================= |
| |
| Type/class unification and new-style classes |
| |
| Core and builtins |
| |
| - A method zfill() was added to str and unicode, that fills a numeric |
| string to the left with zeros. For example, |
| "+123".zfill(6) -> "+00123". |
| |
| - Complex numbers supported divmod() and the // and % operators, but |
| these make no sense. Since this was documented, they're being |
| deprecated now. |
| |
| - String methods lstrip(), rstrip() and strip() now take an optional |
| argument that specifies the characters to strip. For example, |
| "Foo!!!?!?!?".rstrip("?!") -> "Foo". |
| |
| - Added a new dict method pop(key). This removes and returns the |
| value corresponding to key. [SF patch #539949] |
| |
| - Changed new-style class instantiation so that when C's __new__ |
| method returns something that's not a C instance, its __init__ is |
| not called. [SF bug #537450] |
| |
| - Fixed super() to work correctly with class methods. [SF bug #535444] |
| |
| - A new built-in type, bool, has been added, as well as built-in |
| names for its two values, True and False. Comparisons and sundry |
| other operations that return a truth value have been changed to |
| return a bool instead. Read PEP 285 for an explanantion of why this |
| is backward compatible. |
| |
| - Fixed two bugs reported as SF #535905: under certain conditions, |
| deallocating a deeply nested structure could cause a segfault in the |
| garbage collector, due to interaction with the "trashcan" code; |
| access to the current frame during destruction of a local variable |
| could access a pointer to freed memory. |
| |
| - The optional object allocator has been enabled by default. |
| |
| - If you try to pickle an instance of a class that has __slots__ but |
| doesn't define or override __getstate__, a TypeError is now raised. |
| This is done by adding a bozo __getstate__ to the class that always |
| raises TypeError. (Before, this would appear to be pickled, but the |
| state of the slots would be lost.) |
| |
| - PyErr_Display will provide file and line information for all exceptions |
| that have an attribute print_file_and_line, not just SyntaxErrors. |
| |
| - The UTF-8 codec will now encode and decode Unicode surrogates |
| correctly and without raising exceptions for unpaired ones. |
| |
| - file.xreadlines() now raises a ValueError if the file is closed: |
| Previously, an xreadlines object was returned which would raise |
| a ValueError when the xreadlines.next() method was called. |
| |
| - posix.killpg has been added where available. |
| |
| - sys.exit() inadvertantly allowed more than one argument. |
| An exception will now be raised if more than one argument is used. |
| |
| Extension modules |
| |
| - posix.mknod was added. |
| |
| - The locale module now exposes the C library's gettext interface. |
| |
| - A security hole ("double free") was found in zlib-1.1.3, a popular |
| third party compression library used by some Python modules. The |
| hole was quickly plugged in zlib-1.1.4, and the Windows build of |
| Python now ships with zlib-1.1.4. |
| |
| - pwd, grp, and resource return enhanced tuples now, with symbolic |
| field names. |
| |
| - array.array is now a type object. A new format character |
| 'u' indicates Py_UNICODE arrays. For those, .tounicode and |
| .fromunicode methods are available. Arrays now support __iadd__ |
| and __imul__. |
| |
| - dl now builds on every system that has dlfcn.h. Failure in case |
| of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open |
| is called. |
| |
| Library |
| |
| - The UTF-16, -LE and -BE now raise a NotImplementedError |
| for all calls to .readline(). Previously, they used to just |
| produce garbage or fail with an encoding error -- UTF-16 is |
| a 2-byte encoding and the C lib's line reading APIs don't |
| work well with these. |
| |
| - compileall now supports quiet operation. |
| |
| - The BaseHTTPServer implements now optionally HTTP/1.1 persistent |
| connections. |
| |
| - socket module: the SSL support was broken out of the main |
| _socket module C helper and placed into a new _ssl helper |
| which now gets imported by socket.py if available and working. |
| |
| - encodings package: added aliases for all supported IANA character |
| sets |
| |
| - ftplib: to safeguard the user's privacy, anonymous login will use |
| "anonymous@" as default password, rather than the real user and host |
| name. |
| |
| - webbrowser: tightened up the command passed to os.system() so that |
| arbitrary shell code can't be executed because a bogus URL was |
| passed in. |
| |
| - gettext.translation has an optional fallback argument, and |
| gettext.find an optional all argument. Translations will now fallback |
| on a per-message basis. |
| |
| - distutils bdist commands now offer a --skip-build option. |
| |
| - warnings.warn now accepts a Warning instance as first argument. |
| |
| - The xml.sax.expatreader.ExpatParser class will no longer create |
| circular references by using itself as the locator that gets passed |
| to the content handler implementation. [SF bug #535474] |
| |
| Tools/Demos |
| |
| - freeze.py now produces binaries which can import shared modules, |
| unlike before when this failed due to missing symbol exports in |
| the generated binary. |
| |
| Build |
| |
| - On Unix, a shared libpython2.3.so can be created with --enable-shared. |
| |
| - All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS |
| preprocessor symbols were eliminated. The internal decisions they |
| controlled stopped being experimental long ago. |
| |
| C API |
| |
| - The type of tp_free has been changed from "void (*)(PyObject *)" to |
| "void (*)(void *)". |
| |
| - PyObject_Del, PyObject_GC_Del are now functions instead of macros. |
| |
| - A type can now inherit its metatype from its base type. Previously, |
| when PyType_Ready() was called, if ob_type was found to be NULL, it |
| was always set to &PyType_Type; now it is set to base->ob_type, |
| where base is tp_base, defaulting to &PyObject_Type. |
| |
| - PyType_Ready() accidentally did not inherit tp_is_gc; now it does. |
| |
| - Objects allocated using the new PyMalloc_New and PyMalloc_NewVar |
| functions will be allocated using pymalloc if it is enabled. These |
| objects should be deallocated using PyMalloc_Del. The PyObject_{New, |
| NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use |
| PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The |
| PyCore_* family of APIs have been removed. |
| |
| - The "u#" parser marker will now pass through Unicode object as-is |
| without going through the buffer API. |
| |
| - The enumerators of cmp_op have been renamed to use the prefix PyCmp_. |
| |
| - An old #define of ANY as void has been removed from pyport.h. This |
| hasn't been used since Python's pre-ANSI days, and the #define has |
| been marked as obsolete since then. SF bug 495548 says it created |
| conflicts with other packages, so keeping it around wasn't harmless. |
| |
| - Because Python's magic number scheme broke on January 1st, we decided |
| to stop Python development. Thanks for all the fish! |
| |
| - Some of us don't like fish, so we changed Python's magic number |
| scheme to a new one. See Python/import.c for details. |
| |
| New platforms |
| |
| - GNU/Hurd is now supported. |
| |
| Tests |
| |
| Windows |
| |
| - Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031] |
| |
| - The installer now installs Start menu shortcuts under (the local |
| equivalent of) "All Users" when doing an Admin install. |
| |
| - file.truncate([newsize]) now works on Windows for all newsize values. |
| It used to fail if newsize didn't fit in 32 bits, reflecting a |
| limitation of MS _chsize (which is no longer used). |
| |
| - os.waitpid() is now implemented for Windows, and can be used to block |
| until a specified process exits. This is similar to, but not exactly |
| the same as, os.waitpid() on POSIX systems. If you're waiting for |
| a specific process whose pid was obtained from one of the spawn() |
| functions, the same Python os.waitpid() code works across platforms. |
| See the docs for details. The docs were changed to clarify that |
| spawn functions return, and waitpid requires, a process handle on |
| Windows (not the same thing as a Windows process id). |
| |
| - New tempfile.TemporaryFile implementation for Windows: this doesn't |
| need a TemproraryFileWrapper wrapper anymore, and should be immune |
| to a nasty problem: before 2.3, if you got a temp file on Windows, it |
| got wrapped in an object whose close() method first closed the |
| underlying file, then deleted the file. This usually worked fine. |
| However, the spawn family of functions on Windows create (at a low C |
| level) the same set of open files in the spawned process Q as were |
| open in the spawning process P. If a temp file f was among them, then |
| doing f.close() in P first closed P's C-level file handle on f, but Q's |
| C-level file handle on f remained open, so the attempt in P to delete f |
| blew up with a "Permission denied" error (Windows doesn't allow |
| deleting open files). This was surprising, subtle, and difficult to |
| work around. |
| |
| - The os module now exports all the symbolic constants usable with the |
| low-level os.open() on Windows: the new constants in 2.3 are |
| O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL. |
| The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT, |
| O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary |
| to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY |
| (so specify both if you want both; note that neither is useful unless |
| specified with O_CREAT too). |
| |
| Mac |
| |
| |
| What's New in Python 2.2 final? |
| Release date: 21-Dec-2001 |
| =============================== |
| |
| Type/class unification and new-style classes |
| |
| - pickle.py, cPickle: allow pickling instances of new-style classes |
| with a custom metaclass. |
| |
| Core and builtins |
| |
| - weakref proxy object: when comparing, unwrap both arguments if both |
| are proxies. |
| |
| Extension modules |
| |
| - binascii.b2a_base64(): fix a potential buffer overrun when encoding |
| very short strings. |
| |
| - cPickle: the obscure "fast" mode was suspected of causing stack |
| overflows on the Mac. Hopefully fixed this by setting the recursion |
| limit much smaller. If the limit is too low (it only affects |
| performance), you can change it by defining PY_CPICKLE_FAST_LIMIT |
| when compiling cPickle.c (or in pyconfig.h). |
| |
| Library |
| |
| - dumbdbm.py: fixed a dumb old bug (the file didn't get synched at |
| close or delete time). |
| |
| - rfc822.py: fixed a bug where the address '<>' was converted to None |
| instead of an empty string (also fixes the email.Utils module). |
| |
| - xmlrpclib.py: version 1.0.0; uses precision for doubles. |
| |
| - test suite: the pickle and cPickle tests were not executing any code |
| when run from the standard regresssion test. |
| |
| Tools/Demos |
| |
| Build |
| |
| C API |
| |
| New platforms |
| |
| Tests |
| |
| Windows |
| |
| - distutils package: fixed broken Windows installers (bdist_wininst). |
| |
| - tempfile.py: prevent mysterious warnings when TemporaryFileWrapper |
| instances are deleted at process exit time. |
| |
| - socket.py: prevent mysterious warnings when socket instances are |
| deleted at process exit time. |
| |
| - posixmodule.c: fix a Windows crash with stat() of a filename ending |
| in backslash. |
| |
| Mac |
| |
| - The Carbon toolbox modules have been upgraded to Universal Headers |
| 3.4, and experimental CoreGraphics and CarbonEvents modules have |
| been added. All only for framework-enabled MacOSX. |
| |
| |
| What's New in Python 2.2c1? |
| Release date: 14-Dec-2001 |
| =========================== |
| |
| Type/class unification and new-style classes |
| |
| - Guido's tutorial introduction to the new type/class features has |
| been extensively updated. See |
| |
| http://www.python.org/2.2/descrintro.html |
| |
| That remains the primary documentation in this area. |
| |
| - Fixed a leak: instance variables declared with __slots__ were never |
| deleted! |
| |
| - The "delete attribute" method of descriptor objects is called |
| __delete__, not __del__. In previous releases, it was mistakenly |
| called __del__, which created an unfortunate overloading condition |
| with finalizers. (The "get attribute" and "set attribute" methods |
| are still called __get__ and __set__, respectively.) |
| |
| - Some subtle issues with the super built-in were fixed: |
| |
| (a) When super itself is subclassed, its __get__ method would still |
| return an instance of the base class (i.e., of super). |
| |
| (b) super(C, C()).__class__ would return C rather than super. This |
| is confusing. To fix this, I decided to change the semantics of |
| super so that it only applies to code attributes, not to data |
| attributes. After all, overriding data attributes is not |
| supported anyway. |
| |
| (c) The __get__ method didn't check whether the argument was an |
| instance of the type used in creation of the super instance. |
| |
| - Previously, hash() of an instance of a subclass of a mutable type |
| (list or dictionary) would return some value, rather than raising |
| TypeError. This has been fixed. Also, directly calling |
| dict.__hash__ and list.__hash__ now raises the same TypeError |
| (previously, these were the same as object.__hash__). |
| |
| - New-style objects now support deleting their __dict__. This is for |
| all intents and purposes equivalent to assigning a brand new empty |
| dictionary, but saves space if the object is not used further. |
| |
| Core and builtins |
| |
| - -Qnew now works as documented in PEP 238: when -Qnew is passed on |
| the command line, all occurrences of "/" use true division instead |
| of classic division. See the PEP for details. Note that "all" |
| means all instances in library and 3rd-party modules, as well as in |
| your own code. As the PEP says, -Qnew is intended for use only in |
| educational environments with control over the libraries in use. |
| Note that test_coercion.py in the standard Python test suite fails |
| under -Qnew; this is expected, and won't be repaired until true |
| division becomes the default (in the meantime, test_coercion is |
| testing the current rules). |
| |
| - complex() now only allows the first argument to be a string |
| argument, and raises TypeError if either the second arg is a string |
| or if the second arg is specified when the first is a string. |
| |
| Extension modules |
| |
| - gc.get_referents was renamed to gc.get_referrers. |
| |
| Library |
| |
| - Functions in the os.spawn() family now release the global interpreter |
| lock around calling the platform spawn. They should always have done |
| this, but did not before 2.2c1. Multithreaded programs calling |
| an os.spawn function with P_WAIT will no longer block all Python threads |
| until the spawned program completes. It's possible that some programs |
| relies on blocking, although more likely by accident than by design. |
| |
| - webbrowser defaults to netscape.exe on OS/2 now. |
| |
| - Tix.ResizeHandle exposes detach_widget, hide, and show. |
| |
| - The charset alias windows_1252 has been added. |
| |
| - types.StringTypes is a tuple containing the defined string types; |
| usually this will be (str, unicode), but if Python was compiled |
| without Unicode support it will be just (str,). |
| |
| - The pulldom and minidom modules were synchronized to PyXML. |
| |
| Tools/Demos |
| |
| - A new script called Tools/scripts/google.py was added, which fires |
| off a search on Google. |
| |
| Build |
| |
| - Note that release builds of Python should arrange to define the |
| preprocessor symbol NDEBUG on the command line (or equivalent). |
| In the 2.2 pre-release series we tried to define this by magic in |
| Python.h instead, but it proved to cause problems for extension |
| authors. The Unix, Windows and Mac builds now all define NDEBUG in |
| release builds via cmdline (or equivalent) instead. Ports to |
| other platforms should do likewise. |
| |
| - It is no longer necessary to use --with-suffix when building on a |
| case-insensitive file system (such as Mac OS X HFS+). In the build |
| directory an extension is used, but not in the installed python. |
| |
| C API |
| |
| - New function PyDict_MergeFromSeq2() exposes the builtin dict |
| constructor's logic for updating a dictionary from an iterable object |
| producing key-value pairs. |
| |
| - PyArg_ParseTupleAndKeywords() requires that the number of entries in |
| the keyword list equal the number of argument specifiers. This |
| wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even |
| dump core in some bad cases. This has been repaired. As a result, |
| PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that |
| previously went unchallenged. |
| |
| New platforms |
| |
| Tests |
| |
| Windows |
| |
| Mac |
| |
| - In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin", |
| without any trailing digits. |
| |
| - Changed logic for finding python home in Mac OS X framework Pythons. |
| Now sys.executable points to the executable again, in stead of to |
| the shared library. The latter is used only for locating the python |
| home. |
| |
| |
| What's New in Python 2.2b2? |
| Release date: 16-Nov-2001 |
| =========================== |
| |
| Type/class unification and new-style classes |
| |
| - Multiple inheritance mixing new-style and classic classes in the |
| list of base classes is now allowed, so this works now: |
| |
| class Classic: pass |
| class Mixed(Classic, object): pass |
| |
| The MRO (method resolution order) for each base class is respected |
| according to its kind, but the MRO for the derived class is computed |
| using new-style MRO rules if any base clase is a new-style class. |
| This needs to be documented. |
| |
| - The new builtin dictionary() constructor, and dictionary type, have |
| been renamed to dict. This reflects a decade of common usage. |
| |
| - dict() now accepts an iterable object producing 2-sequences. For |
| example, dict(d.items()) == d for any dictionary d. The argument, |
| and the elements of the argument, can be any iterable objects. |
| |
| - New-style classes can now have a __del__ method, which is called |
| when the instance is deleted (just like for classic classes). |
| |
| - Assignment to object.__dict__ is now possible, for objects that are |
| instances of new-style classes that have a __dict__ (unless the base |
| class forbids it). |
| |
| - Methods of built-in types now properly check for keyword arguments |
| (formerly these were silently ignored). The only built-in methods |
| that take keyword arguments are __call__, __init__ and __new__. |
| |
| - The socket function has been converted to a type; see below. |
| |
| Core and builtins |
| |
| - Assignment to __debug__ raises SyntaxError at compile-time. This |
| was promised when 2.1c1 was released as "What's New in Python 2.1c1" |
| (see below) says. |
| |
| - Clarified the error messages for unsupported operands to an operator |
| (like 1 + ''). |
| |
| Extension modules |
| |
| - mmap has a new keyword argument, "access", allowing a uniform way for |
| both Windows and Unix users to create read-only, write-through and |
| copy-on-write memory mappings. This was previously possible only on |
| Unix. A new keyword argument was required to support this in a |
| uniform way because the mmap() signuatures had diverged across |
| platforms. Thanks to Jay T Miller for repairing this! |
| |
| - By default, the gc.garbage list now contains only those instances in |
| unreachable cycles that have __del__ methods; in 2.1 it contained all |
| instances in unreachable cycles. "Instances" here has been generalized |
| to include instances of both new-style and old-style classes. |
| |
| - The socket module defines a new method for socket objects, |
| sendall(). This is like send() but may make multiple calls to |
| send() until all data has been sent. Also, the socket function has |
| been converted to a subclassable type, like list and tuple (etc.) |
| before it; socket and SocketType are now the same thing. |
| |
| - Various bugfixes to the curses module. There is now a test suite |
| for the curses module (you have to run it manually). |
| |
| - binascii.b2a_base64 no longer places an arbitrary restriction of 57 |
| bytes on its input. |
| |
| Library |
| |
| - tkFileDialog exposes a Directory class and askdirectory |
| convenience function. |
| |
| - Symbolic group names in regular expressions must be unique. For |
| example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a |
| single name can't mean both "group 1" and "group 2" simultaneously. |
| Python 2.2 detects this error at regexp compilation time; |
| previously, the error went undetected, and results were |
| unpredictable. Also in sre, the pattern.split(), pattern.sub(), and |
| pattern.subn() methods have been rewritten in C. Also, an |
| experimental function/method finditer() has been added, which works |
| like findall() but returns an iterator. |
| |
| - Tix exposes more commands through the classes DirSelectBox, |
| DirSelectDialog, ListNoteBook, Meter, CheckList, and the |
| methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog, |
| tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions. |
| |
| - Traceback objects are now scanned by cyclic garbage collection, so |
| cycles created by casual use of sys.exc_info() no longer cause |
| permanent memory leaks (provided garbage collection is enabled). |
| |
| - os.extsep -- a new variable needed by the RISCOS support. It is the |
| separator used by extensions, and is '.' on all platforms except |
| RISCOS, where it is '/'. There is no need to use this variable |
| unless you have a masochistic desire to port your code to RISCOS. |
| |
| - mimetypes.py has optional support for non-standard, but commonly |
| found types. guess_type() and guess_extension() now accept an |
| optional `strict' flag, defaulting to true, which controls whether |
| recognize non-standard types or not. A few non-standard types we |
| know about have been added. Also, when run as a script, there are |
| new -l and -e options. |
| |
| - statcache is now deprecated. |
| |
| - email.Utils.formatdate() now produces the preferred RFC 2822 style |
| dates with numeric timezones (it used to produce obsolete dates |
| hard coded to "GMT" timezone). An optional `localtime' flag is |
| added to produce dates in the local timezone, with daylight savings |
| time properly taken into account. |
| |
| - In pickle and cPickle, instead of masking errors in load() by |
| transforming them into SystemError, we let the original exception |
| propagate out. Also, implement support for __safe_for_unpickling__ |
| in pickle, as it already was supported in cPickle. |
| |
| Tools/Demos |
| |
| Build |
| |
| - The dbm module is built using libdb1 if available. The bsddb module |
| is built with libdb3 if available. |
| |
| - Misc/Makefile.pre.in has been removed by BDFL pronouncement. |
| |
| C API |
| |
| - New function PySequence_Fast_GET_SIZE() returns the size of a non- |
| NULL result from PySequence_Fast(), more quickly than calling |
| PySequence_Size(). |
| |
| - New argument unpacking function PyArg_UnpackTuple() added. |
| |
| - New functions PyObject_CallFunctionObjArgs() and |
| PyObject_CallMethodObjArgs() have been added to make it more |
| convenient and efficient to call functions and methods from C. |
| |
| - PyArg_ParseTupleAndKeywords() no longer masks errors, so it's |
| possible that this will propagate errors it didn't before. |
| |
| - New function PyObject_CheckReadBuffer(), which returns true if its |
| argument supports the single-segment readable buffer interface. |
| |
| New platforms |
| |
| - We've finally confirmed that this release builds on HP-UX 11.00, |
| *with* threads, and passes the test suite. |
| |
| - Thanks to a series of patches from Michael Muller, Python may build |
| again under OS/2 Visual Age C++. |
| |
| - Updated RISCOS port by Dietmar Schwertberger. |
| |
| Tests |
| |
| - Added a test script for the curses module. It isn't run automatically; |
| regrtest.py must be run with '-u curses' to enable it. |
| |
| Windows |
| |
| Mac |
| |
| - PythonScript has been moved to unsupported and is slated to be |
| removed completely in the next release. |
| |
| - It should now be possible to build applets that work on both OS9 and |
| OSX. |
| |
| - The core is now linked with CoreServices not Carbon; as a side |
| result, default 8bit encoding on OSX is now ASCII. |
| |
| - Python should now build on OSX 10.1.1 |
| |
| |
| What's New in Python 2.2b1? |
| Release date: 19-Oct-2001 |
| =========================== |
| |
| Type/class unification and new-style classes |
| |
| - New-style classes are now always dynamic (except for built-in and |
| extension types). There is no longer a performance penalty, and I |
| no longer see another reason to keep this baggage around. One relic |
| remains: the __dict__ of a new-style class is a read-only proxy; you |
| must set the class's attribute to modify it. As a consequence, the |
| __defined__ attribute of new-style types no longer exists, for lack |
| of need: there is once again only one __dict__ (although in the |
| future a __cache__ may be resurrected with a similar function, if I |
| can prove that it actually speeds things up). |
| |
| - C.__doc__ now works as expected for new-style classes (in 2.2a4 it |
| always returned None, even when there was a class docstring). |
| |
| - doctest now finds and runs docstrings attached to new-style classes, |
| class methods, static methods, and properties. |
| |
| Core and builtins |
| |
| - A very subtle syntactical pitfall in list comprehensions was fixed. |
| For example: [a+b for a in 'abc', for b in 'def']. The comma in |
| this example is a mistake. Previously, this would silently let 'a' |
| iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce', |
| 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be', |
| 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error. |
| Note that [a for a in <singleton>] is a convoluted way to say |
| [<singleton>] anyway, so it's not like any expressiveness is lost. |
| |
| - getattr(obj, name, default) now only catches AttributeError, as |
| documented, rather than returning the default value for all |
| exceptions (which could mask bugs in a __getattr__ hook, for |
| example). |
| |
| - Weak reference objects are now part of the core and offer a C API. |
| A bug which could allow a core dump when binary operations involved |
| proxy reference has been fixed. weakref.ReferenceError is now a |
| built-in exception. |
| |
| - unicode(obj) now behaves more like str(obj), accepting arbitrary |
| objects, and calling a __unicode__ method if it exists. |
| unicode(obj, encoding) and unicode(obj, encoding, errors) still |
| require an 8-bit string or character buffer argument. |
| |
| - isinstance() now allows any object as the first argument and a |
| class, a type or something with a __bases__ tuple attribute for the |
| second argument. The second argument may also be a tuple of a |
| class, type, or something with __bases__, in which case isinstance() |
| will return true if the first argument is an instance of any of the |
| things contained in the second argument tuple. E.g. |
| |
| isinstance(x, (A, B)) |
| |
| returns true if x is an instance of A or B. |
| |
| Extension modules |
| |
| - thread.start_new_thread() now returns the thread ID (previously None). |
| |
| - binascii has now two quopri support functions, a2b_qp and b2a_qp. |
| |
| - readline now supports setting the startup_hook and the |
| pre_event_hook, and adds the add_history() function. |
| |
| - os and posix supports chroot(), setgroups() and unsetenv() where |
| available. The stat(), fstat(), statvfs() and fstatvfs() functions |
| now return "pseudo-sequences" -- the various fields can now be |
| accessed as attributes (e.g. os.stat("/").st_mtime) but for |
| backwards compatibility they also behave as a fixed-length sequence. |
| Some platform-specific fields (e.g. st_rdev) are only accessible as |
| attributes. |
| |
| - time: localtime(), gmtime() and strptime() now return a |
| pseudo-sequence similar to the os.stat() return value, with |
| attributes like tm_year etc. |
| |
| - Decompression objects in the zlib module now accept an optional |
| second parameter to decompress() that specifies the maximum amount |
| of memory to use for the uncompressed data. |
| |
| - optional SSL support in the socket module now exports OpenSSL |
| functions RAND_add(), RAND_egd(), and RAND_status(). These calls |
| are useful on platforms like Solaris where OpenSSL does not |
| automatically seed its PRNG. Also, the keyfile and certfile |
| arguments to socket.ssl() are now optional. |
| |
| - posixmodule (and by extension, the os module on POSIX platforms) now |
| exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW. |
| |
| Library |
| |
| - doctest now excludes functions and classes not defined by the module |
| being tested, thanks to Tim Hochberg. |
| |
| - HotShot, a new profiler implemented using a C-based callback, has |
| been added. This substantially reduces the overhead of profiling, |
| but it is still quite preliminary. Support modules and |
| documentation will be added in upcoming releases (before 2.2 final). |
| |
| - profile now produces correct output in situations where an exception |
| raised in Python is cleared by C code (e.g. hasattr()). This used |
| to cause wrong output, including spurious claims of recursive |
| functions and attribution of time spent to the wrong function. |
| |
| The code and documentation for the derived OldProfile and HotProfile |
| profiling classes was removed. The code hasn't worked for years (if |
| you tried to use them, they raised exceptions). OldProfile |
| intended to reproduce the behavior of the profiler Python used more |
| than 7 years ago, and isn't interesting anymore. HotProfile intended |
| to provide a faster profiler (but producing less information), and |
| that's a worthy goal we intend to meet via a different approach (but |
| without losing information). |
| |
| - Profile.calibrate() has a new implementation that should deliver |
| a much better system-specific calibration constant. The constant can |
| now be specified in an instance constructor, or as a Profile class or |
| instance variable, instead of by editing profile.py's source code. |
| Calibration must still be done manually (see the docs for the profile |
| module). |
| |
| Note that Profile.calibrate() must be overriden by subclasses. |
| Improving the accuracy required exploiting detailed knowledge of |
| profiler internals; the earlier method abstracted away the details |
| and measured a simplified model instead, but consequently computed |
| a constant too small by a factor of 2 on some modern machines. |
| |
| - quopri's encode and decode methods take an optional header parameter, |
| which indicates whether output is intended for the header 'Q' |
| encoding. |
| |
| - The SocketServer.ThreadingMixIn class now closes the request after |
| finish_request() returns. (Not when it errors out though.) |
| |
| - The nntplib module's NNTP.body() method has grown a `file' argument |
| to allow saving the message body to a file. |
| |
| - The email package has added a class email.Parser.HeaderParser which |
| only parses headers and does not recurse into the message's body. |
| Also, the module/class MIMEAudio has been added for representing |
| audio data (contributed by Anthony Baxter). |
| |
| - ftplib should be able to handle files > 2GB. |
| |
| - ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO, |
| ON, and OFF. |
| |
| - xml.dom.minidom NodeList objects now support the length attribute |
| and item() method as required by the DOM specifications. |
| |
| Tools/Demos |
| |
| - Demo/dns was removed. It no longer serves any purpose; a package |
| derived from it is now maintained by Anthony Baxter, see |
| http://PyDNS.SourceForge.net. |
| |
| - The freeze tool has been made more robust, and two new options have |
| been added: -X and -E. |
| |
| Build |
| |
| - configure will use CXX in LINKCC if CXX is used to build main() and |
| the system requires to link a C++ main using the C++ compiler. |
| |
| C API |
| |
| - The documentation for the tp_compare slot is updated to require that |
| the return value must be -1, 0, 1; an arbitrary number <0 or >0 is |
| not correct. This is not yet enforced but will be enforced in |
| Python 2.3; even later, we may use -2 to indicate errors and +2 for |
| "NotImplemented". Right now, -1 should be used for an error return. |
| |
| - PyLong_AsLongLong() now accepts int (as well as long) arguments. |
| Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well |
| as long) arguments. |
| |
| - PyThread_start_new_thread() now returns a long int giving the thread |
| ID, if one can be calculated; it returns -1 for error, 0 if no |
| thread ID is calculated (this is an incompatible change, but only |
| the thread module used this API). This code has only really been |
| tested on Linux and Windows; other platforms please beware (and |
| report any bugs or strange behavior). |
| |
| - PyUnicode_FromEncodedObject() no longer accepts Unicode objects as |
| input. |
| |
| New platforms |
| |
| Tests |
| |
| Windows |
| |
| - Installer: If you install IDLE, and don't disable file-extension |
| registration, a new "Edit with IDLE" context (right-click) menu entry |
| is created for .py and .pyw files. |
| |
| - The signal module now supports SIGBREAK on Windows, thanks to Steven |
| Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK |
| action remains to call Win32 ExitProcess(). This can be changed via |
| signal.signal(). For example: |
| |
| # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C |
| # (SIGINT) behavior. |
| import signal |
| signal.signal(signal.SIGBREAK, |
| signal.default_int_handler) |
| |
| try: |
| while 1: |
| pass |
| except KeyboardInterrupt: |
| # We get here on Ctrl+C or Ctrl+Break now; if we had not changed |
| # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the |
| # program without the possibility for any Python-level cleanup). |
| print "Clean exit" |
| |
| |
| What's New in Python 2.2a4? |
| Release date: 28-Sep-2001 |
| =========================== |
| |
| Type/class unification and new-style classes |
| |
| - pydoc and inspect are now aware of new-style classes; |
| e.g. help(list) at the interactive prompt now shows proper |
| documentation for all operations on list objects. |
| |
| - Applications using Jim Fulton's ExtensionClass module can now safely |
| be used with Python 2.2. In particular, Zope 2.4.1 now works with |
| Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass |
| examples also work again. It is hoped that Gtk and Boost also work |
| with 2.2a4 and beyond. (If you can confirm this, please write |
| webmaster@python.org; if there are still problems, please open a bug |
| report on SourceForge.) |
| |
| - property() now takes 4 keyword arguments: fget, fset, fdel and doc. |
| These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__' |
| in the constructed property object. fget, fset and fdel weren't |
| discoverable from Python in 2.2a3. __doc__ is new, and allows to |
| associate a docstring with a property. |
| |
| - Comparison overloading is now more completely implemented. For |
| example, a str subclass instance can properly be compared to a str |
| instance, and it can properly overload comparison. Ditto for most |
| other built-in object types. |
| |
| - The repr() of new-style classes has changed; instead of <type |
| 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>, |
| *except* for built-in types, which are still rendered as <type |
| 'Foo'> (to avoid upsetting existing code that might parse or |
| otherwise rely on repr() of certain type objects). |
| |
| - The repr() of new-style objects is now always <Foo object at XXX>; |
| previously, it was sometimes <Foo instance at XXX>. |
| |
| - For new-style classes, what was previously called __getattr__ is now |
| called __getattribute__. This method, if defined, is called for |
| *every* attribute access. A new __getattr__ hook more similar to the |
| one in classic classes is defined which is called only if regular |
| attribute access raises AttributeError; to catch *all* attribute |
| access, you can use __getattribute__ (for new-style classes). If |
| both are defined, __getattribute__ is called first, and if it raises |
| AttributeError, __getattr__ is called. |
| |
| - The __class__ attribute of new-style objects can be assigned to. |
| The new class must have the same C-level object layout as the old |
| class. |
| |
| - The builtin file type can be subclassed now. In the usual pattern, |
| "file" is the name of the builtin type, and file() is a new builtin |
| constructor, with the same signature as the builtin open() function. |
| file() is now the preferred way to open a file. |
| |
| - Previously, __new__ would only see sequential arguments passed to |
| the type in a constructor call; __init__ would see both sequential |
| and keyword arguments. This made no sense whatsoever any more, so |
| now both __new__ and __init__ see all arguments. |
| |
| - Previously, hash() applied to an instance of a subclass of str or |
| unicode always returned 0. This has been repaired. |
| |
| - Previously, an operation on an instance of a subclass of an |
| immutable type (int, long, float, complex, tuple, str, unicode), |
| where the subtype didn't override the operation (and so the |
| operation was handled by the builtin type), could return that |
| instance instead a value of the base type. For example, if s was of |
| a str sublass type, s[:] returned s as-is. Now it returns a str |
| with the same value as s. |
| |
| - Provisional support for pickling new-style objects has been added. |
| |
| Core |
| |
| - file.writelines() now accepts any iterable object producing strings. |
| |
| - PyUnicode_FromEncodedObject() now works very much like |
| PyObject_Str(obj) in that it tries to use __str__/tp_str |
| on the object if the object is not a string or buffer. This |
| makes unicode() behave like str() when applied to non-string/buffer |
| objects. |
| |
| - PyFile_WriteObject now passes Unicode objects to the file's write |
| method. As a result, all file-like objects which may be the target |
| of a print statement must support Unicode objects, i.e. they must |
| at least convert them into ASCII strings. |
| |
| - Thread scheduling on Solaris should be improved; it is no longer |
| necessary to insert a small sleep at the start of a thread in order |
| to let other runnable threads be scheduled. |
| |
| Library |
| |
| - StringIO.StringIO instances and cStringIO.StringIO instances support |
| read character buffer compatible objects for their .write() methods. |
| These objects are converted to strings and then handled as such |
| by the instances. |
| |
| - The "email" package has been added. This is basically a port of the |
| mimelib package <http://sf.net/projects/mimelib> with API changes |
| and some implementations updated to use iterators and generators. |
| |
| - difflib.ndiff() and difflib.Differ.compare() are generators now. This |
| restores the ability of Tools/scripts/ndiff.py to start producing output |
| before the entire comparison is complete. |
| |
| - StringIO.StringIO instances and cStringIO.StringIO instances support |
| iteration just like file objects (i.e. their .readline() method is |
| called for each iteration until it returns an empty string). |
| |
| - The codecs module has grown four new helper APIs to access |
| builtin codecs: getencoder(), getdecoder(), getreader(), |
| getwriter(). |
| |
| - SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer) |
| simplifies writing XML RPC servers. |
| |
| - os.path.realpath(): a new function that returns the absolute pathname |
| after interpretation of symbolic links. On non-Unix systems, this |
| is an alias for os.path.abspath(). |
| |
| - operator.indexOf() (PySequence_Index() in the C API) now works with any |
| iterable object. |
| |
| - smtplib now supports various authentication and security features of |
| the SMTP protocol through the new login() and starttls() methods. |
| |
| - hmac: a new module implementing keyed hashing for message |
| authentication. |
| |
| - mimetypes now recognizes more extensions and file types. At the |
| same time, some mappings not sanctioned by IANA were removed. |
| |
| - The "compiler" package has been brought up to date to the state of |
| Python 2.2 bytecode generation. It has also been promoted from a |
| Tool to a standard library package. (Tools/compiler still exists as |
| a sample driver.) |
| |
| Tools |
| |
| Build |
| |
| - Large file support (LFS) is now automatic when the platform supports |
| it; no more manual configuration tweaks are needed. On Linux, at |
| least, it's possible to have a system whose C library supports large |
| files but whose kernel doesn't; in this case, large file support is |
| still enabled but doesn't do you any good unless you upgrade your |
| kernel or share your Python executable with another system whose |
| kernel has large file support. |
| |
| - The configure script now supplies plausible defaults in a |
| cross-compilation environment. This doesn't mean that the supplied |
| values are always correct, or that cross-compilation now works |
| flawlessly -- but it's a first step (and it shuts up most of |
| autoconf's warnings about AC_TRY_RUN). |
| |
| - The Unix build is now a bit less chatty, courtesy of the parser |
| generator. The build is completely silent (except for errors) when |
| using "make -s", thanks to a -q option to setup.py. |
| |
| C API |
| |
| - The "structmember" API now supports some new flag bits to deny read |
| and/or write access to attributes in restricted execution mode. |
| |
| New platforms |
| |
| - Compaq's iPAQ handheld, running the "familiar" Linux distribution |
| (http://familiar.handhelds.org). |
| |
| Tests |
| |
| - The "classic" standard tests, which work by comparing stdout to |
| an expected-output file under Lib/test/output/, no longer stop at |
| the first mismatch. Instead the test is run to completion, and a |
| variant of ndiff-style comparison is used to report all differences. |
| This is much easier to understand than the previous style of reporting. |
| |
| - The unittest-based standard tests now use regrtest's test_main() |
| convention, instead of running as a side-effect of merely being |
| imported. This allows these tests to be run in more natural and |
| flexible ways as unittests, outside the regrtest framework. |
| |
| - regrtest.py is much better integrated with unittest and doctest now, |
| especially in regard to reporting errors. |
| |
| Windows |
| |
| - Large file support now also works for files > 4GB, on filesystems |
| that support it (NTFS under Windows 2000). See "What's New in |
| Python 2.2a3" for more detail. |
| |
| |
| What's New in Python 2.2a3? |
| Release Date: 07-Sep-2001 |
| =========================== |
| |
| Core |
| |
| - Conversion of long to float now raises OverflowError if the long is too |
| big to represent as a C double. |
| |
| - The 3-argument builtin pow() no longer allows a third non-None argument |
| if either of the first two arguments is a float, or if both are of |
| integer types and the second argument is negative (in which latter case |
| the arguments are converted to float, so this is really the same |
| restriction). |
| |
| - The builtin dir() now returns more information, and sometimes much |
| more, generally naming all attributes of an object, and all attributes |
| reachable from the object via its class, and from its class's base |
| classes, and so on from them too. Example: in 2.2a2, dir([]) returned |
| an empty list. In 2.2a3, |
| |
| >>> dir([]) |
| ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', |
| '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__', |
| '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__', |
| '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__', |
| '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__', |
| 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', |
| 'reverse', 'sort'] |
| |
| dir(module) continues to return only the module's attributes, though. |
| |
| - Overflowing operations on plain ints now return a long int rather |
| than raising OverflowError. This is a partial implementation of PEP |
| 237. You can use -Wdefault::OverflowWarning to enable a warning for |
| this situation, and -Werror::OverflowWarning to revert to the old |
| OverflowError exception. |
| |
| - A new command line option, -Q<arg>, is added to control run-time |
| warnings for the use of classic division. (See PEP 238.) Possible |
| values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is |
| -Qold, meaning the / operator has its classic meaning and no |
| warnings are issued. Using -Qwarn issues a run-time warning about |
| all uses of classic division for int and long arguments; -Qwarnall |
| also warns about classic division for float and complex arguments |
| (for use with fixdiv.py). |
| [Note: the remainder of this paragraph (preserved below) became |
| obsolete in 2.2c1 -- -Qnew has global effect in 2.2] |
| <obsolete> |
| Using -Qnew is questionable; it turns on new division by default, but |
| only in the __main__ module. You can usefully combine -Qwarn or |
| -Qwarnall and -Qnew: this gives the __main__ module new division, and |
| warns about classic division everywhere else. |
| </obsolete> |
| |
| - Many built-in types can now be subclassed. This applies to int, |
| long, float, str, unicode, and tuple. (The types complex, list and |
| dictionary can also be subclassed; this was introduced earlier.) |
| Note that restrictions apply when subclassing immutable built-in |
| types: you can only affect the value of the instance by overloading |
| __new__. You can add mutable attributes, and the subclass instances |
| will have a __dict__ attribute, but you cannot change the "value" |
| (as implemented by the base class) of an immutable subclass instance |
| once it is created. |
| |
| - The dictionary constructor now takes an optional argument, a |
| mapping-like object, and initializes the dictionary from its |
| (key, value) pairs. |
| |
| - A new built-in type, super, has been added. This facilitates making |
| "cooperative super calls" in a multiple inheritance setting. For an |
| explanation, see http://www.python.org/2.2/descrintro.html#cooperation |
| |
| - A new built-in type, property, has been added. This enables the |
| creation of "properties". These are attributes implemented by |
| getter and setter functions (or only one of these for read-only or |
| write-only attributes), without the need to override __getattr__. |
| See http://www.python.org/2.2/descrintro.html#property |
| |
| - The syntax of floating-point and imaginary literals has been |
| liberalized, to allow leading zeroes. Examples of literals now |
| legal that were SyntaxErrors before: |
| |
| 00.0 0e3 0100j 07.5 00000000000000000008. |
| |
| - An old tokenizer bug allowed floating point literals with an incomplete |
| exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError. |
| |
| Library |
| |
| - telnetlib includes symbolic names for the options, and support for |
| setting an option negotiation callback. |
| |
| - The new C standard no longer requires that math libraries set errno to |
| ERANGE on overflow. For platform libraries that exploit this new |
| freedom, Python's overflow-checking was wholly broken. A new overflow- |
| checking scheme attempts to repair that, but may not be reliable on all |
| platforms (C doesn't seem to provide anything both useful and portable |
| in this area anymore). |
| |
| - Asynchronous timeout actions are available through the new class |
| threading.Timer. |
| |
| - math.log and math.log10 now return sensible results for even huge |
| long arguments. For example, math.log10(10 ** 10000) ~= 10000.0. |
| |
| - A new function, imp.lock_held(), returns 1 when the import lock is |
| currently held. See the docs for the imp module. |
| |
| - pickle, cPickle and marshal on 32-bit platforms can now correctly read |
| dumps containing ints written on platforms where Python ints are 8 bytes. |
| When read on a box where Python ints are 4 bytes, such values are |
| converted to Python longs. |
| |
| - In restricted execution mode (using the rexec module), unmarshalling |
| code objects is no longer allowed. This plugs a security hole. |
| |
| - unittest.TestResult instances no longer store references to tracebacks |
| generated by test failures. This prevents unexpected dangling references |
| to objects that should be garbage collected between tests. |
| |
| Tools |
| |
| - Tools/scripts/fixdiv.py has been added which can be used to fix |
| division operators as per PEP 238. |
| |
| Build |
| |
| - If you are an adventurous person using Mac OS X you may want to look at |
| Mac/OSX. There is a Makefile there that will build Python as a real Mac |
| application, which can be used for experimenting with Carbon or Cocoa. |
| Discussion of this on pythonmac-sig, please. |
| |
| C API |
| |
| - New function PyObject_Dir(obj), like Python __builtin__.dir(obj). |
| |
| - Note that PyLong_AsDouble can fail! This has always been true, but no |
| callers checked for it. It's more likely to fail now, because overflow |
| errors are properly detected now. The proper way to check: |
| |
| double x = PyLong_AsDouble(some_long_object); |
| if (x == -1.0 && PyErr_Occurred()) { |
| /* The conversion failed. */ |
| } |
| |
| - The GC API has been changed. Extensions that use the old API will still |
| compile but will not participate in GC. To upgrade an extension |
| module: |
| |
| - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC |
| |
| - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and |
| PyObject_GC_Del to deallocate them |
| |
| - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini |
| to PyObject_GC_UnTrack |
| |
| - remove PyGC_HEAD_SIZE from object size calculations |
| |
| - remove calls to PyObject_AS_GC and PyObject_FROM_GC |
| |
| - Two new functions: PyString_FromFormat() and PyString_FromFormatV(). |
| These can be used safely to construct string objects from a |
| sprintf-style format string (similar to the format string supported |
| by PyErr_Format()). |
| |
| New platforms |
| |
| - Stephen Hansen contributed patches sufficient to get a clean compile |
| under Borland C (Windows), but he reports problems running it and ran |
| out of time to complete the port. Volunteers? Expect a MemoryError |
| when importing the types module; this is probably shallow, and |
| causing later failures too. |
| |
| Tests |
| |
| Windows |
| |
| - Large file support is now enabled on Win32 platforms as well as on |
| Win64. This means that, for example, you can use f.tell() and f.seek() |
| to manipulate files larger than 2 gigabytes (provided you have enough |
| disk space, and are using a Windows filesystem that supports large |
| partitions). Windows filesystem limits: FAT has a 2GB (gigabyte) |
| filesize limit, and large file support makes no difference there. |
| FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now. |
| NTFS has no practical limit on file size, and files of any size can be |
| used from Python now. |
| |
| - The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC |
| points to command.com (patch from Brian Quinlan). |
| |
| |
| What's New in Python 2.2a2? |
| Release Date: 22-Aug-2001 |
| =========================== |
| |
| Build |
| |
| - Tim Peters developed a brand new Windows installer using Wise 8.1, |
| generously donated to us by Wise Solutions. |
| |
| - configure supports a new option --enable-unicode, with the values |
| ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode |
| type and supporting code is completely removed from the interpreter. |
| |
| - A new configure option --enable-framework builds a Mac OS X framework, |
| which "make frameworkinstall" will install. This provides a starting |
| point for more mac-like functionality, join pythonmac-sig@python.org |
| if you are interested in helping. |
| |
| - The NeXT platform is no longer supported. |
| |
| - The `new' module is now statically linked. |
| |
| Tools |
| |
| - The new Tools/scripts/cleanfuture.py can be used to automatically |
| edit out obsolete future statements from Python source code. See |
| the module docstring for details. |
| |
| Tests |
| |
| - regrtest.py now knows which tests are expected to be skipped on some |
| platforms, allowing to give clearer test result output. regrtest |
| also has optional --use/-u switch to run normally disabled tests |
| which require network access or consume significant disk resources. |
| |
| - Several new tests in the standard test suite, with special thanks to |
| Nick Mathewson. |
| |
| Core |
| |
| - The floor division operator // has been added as outlined in PEP |
| 238. The / operator still provides classic division (and will until |
| Python 3.0) unless "from __future__ import division" is included, in |
| which case the / operator will provide true division. The operator |
| module provides truediv() and floordiv() functions. Augmented |
| assignment variants are included, as are the equivalent overloadable |
| methods and C API methods. See the PEP for a full discussion: |
| <http://python.sf.net/peps/pep-0238.html> |
| |
| - Future statements are now effective in simulated interactive shells |
| (like IDLE). This should "just work" by magic, but read Michael |
| Hudson's "Future statements in simulated shells" PEP 264 for full |
| details: <http://python.sf.net/peps/pep-0264.html>. |
| |
| - The type/class unification (PEP 252-253) was integrated into the |
| trunk and is not so tentative any more (the exact specification of |
| some features is still tentative). A lot of work has done on fixing |
| bugs and adding robustness and features (performance still has to |
| come a long way). |
| |
| - Warnings about a mismatch in the Python API during extension import |
| now use the Python warning framework (which makes it possible to |
| write filters for these warnings). |
| |
| - A function's __dict__ (aka func_dict) will now always be a |
| dictionary. It used to be possible to delete it or set it to None, |
| but now both actions raise TypeErrors. It is still legal to set it |
| to a dictionary object. Getting func.__dict__ before any attributes |
| have been assigned now returns an empty dictionary instead of None. |
| |
| - A new command line option, -E, was added which disables the use of |
| all environment variables, or at least those that are specifically |
| significant to Python. Usually those have a name starting with |
| "PYTHON". This was used to fix a problem where the tests fail if |
| the user happens to have PYTHONHOME or PYTHONPATH pointing to an |
| older distribution. |
| |
| Library |
| |
| - New class Differ and new functions ndiff() and restore() in difflib.py. |
| These package the algorithms used by the popular Tools/scripts/ndiff.py, |
| for programmatic reuse. |
| |
| - New function xml.sax.saxutils.quoteattr(): Quote an XML attribute |
| value using the minimal quoting required for the value; more |
| reliable than using xml.sax.saxutils.escape() for attribute values. |
| |
| - Readline completion support for cmd.Cmd was added. |
| |
| - Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings. |
| |
| - Added function threading.BoundedSemaphore() |
| |
| - Added Ka-Ping Yee's cgitb.py module. |
| |
| - The `new' module now exposes the CO_xxx flags. |
| |
| - The gc module offers the get_referents function. |
| |
| New platforms |
| |
| C API |
| |
| - Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added |
| which provide a cross-platform implementations for the |
| relatively new snprintf()/vsnprintf() C lib APIs. In contrast to |
| the standard sprintf() and vsprintf() C lib APIs, these versions |
| apply bounds checking on the used buffer which enhances protection |
| against buffer overruns. |
| |
| - Unicode APIs now use name mangling to assure that mixing interpreters |
| and extensions using different Unicode widths is rendered next to |
| impossible. Trying to import an incompatible Unicode-aware extension |
| will result in an ImportError. Unicode extensions writers must make |
| sure to check the Unicode width compatibility in their extensions by |
| using at least one of the mangled Unicode APIs in the extension. |
| |
| - Two new flags METH_NOARGS and METH_O are available in method definition |
| tables to simplify implementation of methods with no arguments and a |
| single untyped argument. Calling such methods is more efficient than |
| calling corresponding METH_VARARGS methods. METH_OLDARGS is now |
| deprecated. |
| |
| Windows |
| |
| - "import module" now compiles module.pyw if it exists and nothing else |
| relevant is found. |
| |
| |
| What's New in Python 2.2a1? |
| Release date: 18-Jul-2001 |
| =========================== |
| |
| Core |
| |
| - TENTATIVELY, a large amount of code implementing much of what's |
| described in PEP 252 (Making Types Look More Like Classes) and PEP |
| 253 (Subtyping Built-in Types) was added. This will be released |
| with Python 2.2a1. Documentation will be provided separately |
| through http://www.python.org/2.2/. The purpose of releasing this |
| with Python 2.2a1 is to test backwards compatibility. It is |
| possible, though not likely, that a decision is made not to release |
| this code as part of 2.2 final, if any serious backwards |
| incompapatibilities are found during alpha testing that cannot be |
| repaired. |
| |
| - Generators were added; this is a new way to create an iterator (see |
| below) using what looks like a simple function containing one or |
| more 'yield' statements. See PEP 255. Since this adds a new |
| keyword to the language, this feature must be enabled by including a |
| future statement: "from __future__ import generators" (see PEP 236). |
| Generators will become a standard feature in a future release |
| (probably 2.3). Without this future statement, 'yield' remains an |
| ordinary identifier, but a warning is issued each time it is used. |
| (These warnings currently don't conform to the warnings framework of |
| PEP 230; we intend to fix this in 2.2a2.) |
| |
| - The UTF-16 codec was modified to be more RFC compliant. It will now |
| only remove BOM characters at the start of the string and then |
| only if running in native mode (UTF-16-LE and -BE won't remove a |
| leading BMO character). |
| |
| - Strings now have a new method .decode() to complement the already |
| existing .encode() method. These two methods provide direct access |
| to the corresponding decoders and encoders of the registered codecs. |
| |
| To enhance the usability of the .encode() method, the special |
| casing of Unicode object return values was dropped (Unicode objects |
| were auto-magically converted to string using the default encoding). |
| |
| Both methods will now return whatever the codec in charge of the |
| requested encoding returns as object, e.g. Unicode codecs will |
| return Unicode objects when decoding is requested ("äöü".decode("latin-1") |
| will return u"äöü"). This enables codec writer to create codecs |
| for various simple to use conversions. |
| |
| New codecs were added to demonstrate these new features (the .encode() |
| and .decode() columns indicate the type of the returned objects): |
| |
| Name | .encode() | .decode() | Description |
| ---------------------------------------------------------------------- |
| uu | string | string | UU codec (e.g. for email) |
| base64 | string | string | base64 codec |
| quopri | string | string | quoted-printable codec |
| zlib | string | string | zlib compression |
| hex | string | string | 2-byte hex codec |
| rot-13 | string | Unicode | ROT-13 Unicode charmap codec |
| |
| - Some operating systems now support the concept of a default Unicode |
| encoding for file system operations. Notably, Windows supports 'mbcs' |
| as the default. The Macintosh will also adopt this concept in the medium |
| term, although the default encoding for that platform will be other than |
| 'mbcs'. |
| |
| On operating system that support non-ASCII filenames, it is common for |
| functions that return filenames (such as os.listdir()) to return Python |
| string objects pre-encoded using the default file system encoding for |
| the platform. As this encoding is likely to be different from Python's |
| default encoding, converting this name to a Unicode object before passing |
| it back to the Operating System would result in a Unicode error, as Python |
| would attempt to use its default encoding (generally ASCII) rather than |
| the default encoding for the file system. |
| |
| In general, this change simply removes surprises when working with |
| Unicode and the file system, making these operations work as you expect, |
| increasing the transparency of Unicode objects in this context. |
| See [????] for more details, including examples. |
| |
| - Float (and complex) literals in source code were evaluated to full |
| precision only when running from a .py file; the same code loaded from a |
| .pyc (or .pyo) file could suffer numeric differences starting at about the |
| 12th significant decimal digit. For example, on a machine with IEEE-754 |
| floating arithmetic, |
| |
| x = 9007199254740992.0 |
| print long(x) |
| |
| printed 9007199254740992 if run directly from .py, but 9007199254740000 |
| if from a compiled (.pyc or .pyo) file. This was due to marshal using |
| str(float) instead of repr(float) when building code objects. marshal |
| now uses repr(float) instead, which should reproduce floats to full |
| machine precision (assuming the platform C float<->string I/O conversion |
| functions are of good quality). |
| |
| This may cause floating-point results to change in some cases, and |
| usually for the better, but may also cause numerically unstable |
| algorithms to break. |
| |
| - The implementation of dicts suffers fewer collisions, which has speed |
| benefits. However, the order in which dict entries appear in dict.keys(), |
| dict.values() and dict.items() may differ from previous releases for a |
| given dict. Nothing is defined about this order, so no program should |
| rely on it. Nevertheless, it's easy to write test cases that rely on the |
| order by accident, typically because of printing the str() or repr() of a |
| dict to an "expected results" file. See Lib/test/test_support.py's new |
| sortdict(dict) function for a simple way to display a dict in sorted |
| order. |
| |
| - Many other small changes to dicts were made, resulting in faster |
| operation along the most common code paths. |
| |
| - Dictionary objects now support the "in" operator: "x in dict" means |
| the same as dict.has_key(x). |
| |
| - The update() method of dictionaries now accepts generic mapping |
| objects. Specifically the argument object must support the .keys() |
| and __getitem__() methods. This allows you to say, for example, |
| {}.update(UserDict()) |
| |
| - Iterators were added; this is a generalized way of providing values |
| to a for loop. See PEP 234. There's a new built-in function iter() |
| to return an iterator. There's a new protocol to get the next value |
| from an iterator using the next() method (in Python) or the |
| tp_iternext slot (in C). There's a new protocol to get iterators |
| using the __iter__() method (in Python) or the tp_iter slot (in C). |
| Iterating (i.e. a for loop) over a dictionary generates its keys. |
| Iterating over a file generates its lines. |
| |
| - The following functions were generalized to work nicely with iterator |
| arguments: |
| map(), filter(), reduce(), zip() |
| list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API) |
| max(), min() |
| join() method of strings |
| extend() method of lists |
| 'x in y' and 'x not in y' (PySequence_Contains() in C API) |
| operator.countOf() (PySequence_Count() in C API) |
| right-hand side of assignment statements with multiple targets, such as |
| x, y, z = some_iterable_object_returning_exactly_3_values |
| |
| - Accessing module attributes is significantly faster (for example, |
| random.random or os.path or yourPythonModule.yourAttribute). |
| |
| - Comparing dictionary objects via == and != is faster, and now works even |
| if the keys and values don't support comparisons other than ==. |
| |
| - Comparing dictionaries in ways other than == and != is slower: there were |
| insecurities in the dict comparison implementation that could cause Python |
| to crash if the element comparison routines for the dict keys and/or |
| values mutated the dicts. Making the code bulletproof slowed it down. |
| |
| - Collisions in dicts are resolved via a new approach, which can help |
| dramatically in bad cases. For example, looking up every key in a dict |
| d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x |
| faster now. Thanks to Christian Tismer for pointing out the cause and |
| the nature of an effective cure (last December! better late than never). |
| |
| - repr() is much faster for large containers (dict, list, tuple). |
| |
| |
| Library |
| |
| - The constants ascii_letters, ascii_lowercase. and ascii_uppercase |
| were added to the string module. These a locale-indenpendent |
| constants, unlike letters, lowercase, and uppercase. These are now |
| use in appropriate locations in the standard library. |
| |
| - The flags used in dlopen calls can now be configured using |
| sys.setdlopenflags and queried using sys.getdlopenflags. |
| |
| - Fredrik Lundh's xmlrpclib is now a standard library module. This |
| provides full client-side XML-RPC support. In addition, |
| Demo/xmlrpc/ contains two server frameworks (one SocketServer-based, |
| one asyncore-based). Thanks to Eric Raymond for the documentation. |
| |
| - The xrange() object is simplified: it no longer supports slicing, |
| repetition, comparisons, efficient 'in' checking, the tolist() |
| method, or the start, stop and step attributes. See PEP 260. |
| |
| - A new function fnmatch.filter to filter lists of file names was added. |
| |
| - calendar.py uses month and day names based on the current locale. |
| |
| - strop is now *really* obsolete (this was announced before with 1.6), |
| and issues DeprecationWarning when used (except for the four items |
| that are still imported into string.py). |
| |
| - Cookie.py now sorts key+value pairs by key in output strings. |
| |
| - pprint.isrecursive(object) didn't correctly identify recursive objects. |
| Now it does. |
| |
| - pprint functions now much faster for large containers (tuple, list, dict). |
| |
| - New 'q' and 'Q' format codes in the struct module, corresponding to C |
| types "long long" and "unsigned long long" (on Windows, __int64). In |
| native mode, these can be used only when the platform C compiler supports |
| these types (when HAVE_LONG_LONG is #define'd by the Python config |
| process), and then they inherit the sizes and alignments of the C types. |
| In standard mode, 'q' and 'Q' are supported on all platforms, and are |
| 8-byte integral types. |
| |
| - The site module installs a new built-in function 'help' that invokes |
| pydoc.help. It must be invoked as 'help()'; when invoked as 'help', |
| it displays a message reminding the user to use 'help()' or |
| 'help(object)'. |
| |
| Tests |
| |
| - New test_mutants.py runs dict comparisons where the key and value |
| comparison operators mutute the dicts randomly during comparison. This |
| rapidly causes Python to crash under earlier releases (not for the faint |
| of heart: it can also cause Win9x to freeze or reboot!). |
| |
| - New test_pprint.py verfies that pprint.isrecursive() and |
| pprint.isreadable() return sensible results. Also verifies that simple |
| cases produce correct output. |
| |
| C API |
| |
| - Removed the unused last_is_sticky argument from the internal |
| _PyTuple_Resize(). If this affects you, you were cheating. |
| |
| |
| ====================================================================== |
| |
| |
| What's New in Python 2.1 (final)? |
| ================================= |
| |
| We only changed a few things since the last release candidate, all in |
| Python library code: |
| |
| - A bug in the locale module was fixed that affected locales which |
| define no grouping for numeric formatting. |
| |
| - A few bugs in the weakref module's implementations of weak |
| dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed, |
| and the test suite was updated to check for these bugs. |
| |
| - An old bug in the os.path.walk() function (introduced in Python |
| 2.0!) was fixed: a non-existent file would cause an exception |
| instead of being ignored. |
| |
| - Fixed a few bugs in the new symtable module found by Neil Norwitz's |
| PyChecker. |
| |
| |
| What's New in Python 2.1c2? |
| =========================== |
| |
| A flurry of small changes, and one showstopper fixed in the nick of |
| time made it necessary to release another release candidate. The list |
| here is the *complete* list of patches (except version updates): |
| |
| Core |
| |
| - Tim discovered a nasty bug in the dictionary code, caused by |
| PyDict_Next() calling dict_resize(), and the GC code's use of |
| PyDict_Next() violating an assumption in dict_items(). This was |
| fixed with considerable amounts of band-aid, but the net effect is a |
| saner and more robust implementation. |
| |
| - Made a bunch of symbols static that were accidentally global. |
| |
| Build and Ports |
| |
| - The setup.py script didn't check for a new enough version of zlib |
| (1.1.3 is needed). Now it does. |
| |
| - Changed "make clean" target to also remove shared libraries. |
| |
| - Added a more general warning about the SGI Irix optimizer to README. |
| |
| Library |
| |
| - Fix a bug in urllib.basejoin("http://host", "../file.html") which |
| omitted the slash between host and file.html. |
| |
| - The mailbox module's _Mailbox class contained a completely broken |
| and undocumented seek() method. Ripped it out. |
| |
| - Fixed a bunch of typos in various library modules (urllib2, smtpd, |
| sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker. |
| |
| - Fixed a few last-minute bugs in unittest. |
| |
| Extensions |
| |
| - Reverted the patch to the OpenSSL code in socketmodule.c to support |
| RAND_status() and the EGD, and the subsequent patch that tried to |
| fix it for pre-0.9.5 versions; the problem with the patch is that on |
| some systems it issues a warning whenever socket is imported, and |
| that's unacceptable. |
| |
| Tests |
| |
| - Fixed the pickle tests to work with "import test.test_pickle". |
| |
| - Tweaked test_locale.py to actually run the test Windows. |
| |
| - In distutils/archive_util.py, call zipfile.ZipFile() with mode "w", |
| not "wb" (which is not a valid mode at all). |
| |
| - Fix pstats browser crashes. Import readline if it exists to make |
| the user interface nicer. |
| |
| - Add "import thread" to the top of test modules that import the |
| threading module (test_asynchat and test_threadedtempfile). This |
| prevents test failures caused by a broken threading module resulting |
| from a previously caught failed import. |
| |
| - Changed test_asynchat.py to set the SO_REUSEADDR option; this was |
| needed on some platforms (e.g. Solaris 8) when the tests are run |
| twice in succession. |
| |
| - Skip rather than fail test_sunaudiodev if no audio device is found. |
| |
| |
| What's New in Python 2.1c1? |
| =========================== |
| |
| This list was significantly updated when 2.1c2 was released; the 2.1c1 |
| release didn't mention most changes that were actually part of 2.1c1: |
| |
| Legal |
| |
| - Copyright was assigned to the Python Software Foundation (PSF) and a |
| PSF license (very similar to the CNRI license) was added. |
| |
| - The CNRI copyright notice was updated to include 2001. |
| |
| Core |
| |
| - After a public outcry, assignment to __debug__ is no longer illegal; |
| instead, a warning is issued. It will become illegal in 2.2. |
| |
| - Fixed a core dump with "%#x" % 0, and changed the semantics so that |
| "%#x" now always prepends "0x", even if the value is zero. |
| |
| - Fixed some nits in the bytecode compiler. |
| |
| - Fixed core dumps when calling certain kinds of non-functions. |
| |
| - Fixed various core dumps caused by reference count bugs. |
| |
| Build and Ports |
| |
| - Use INSTALL_SCRIPT to install script files. |
| |
| - New port: SCO Unixware 7, by Billy G. Allie. |
| |
| - Updated RISCOS port. |
| |
| - Updated BeOS port and notes. |
| |
| - Various other porting problems resolved. |
| |
| Library |
| |
| - The TERMIOS and SOCKET modules are now truly obsolete and |
| unnecessary. Their symbols are incorporated in the termios and |
| socket modules. |
| |
| - Fixed some 64-bit bugs in pickle, cPickle, and struct, and added |
| better tests for pickling. |
| |
| - threading: make Condition.wait() robust against KeyboardInterrupt. |
| |
| - zipfile: add support to zipfile to support opening an archive |
| represented by an open file rather than a file name. Fix bug where |
| the archive was not properly closed. Fixed a bug in this bugfix |
| where flush() was called for a read-only file. |
| |
| - imputil: added an uninstall() method to the ImportManager. |
| |
| - Canvas: fixed bugs in lower() and tkraise() methods. |
| |
| - SocketServer: API change (added overridable close_request() method) |
| so that the TCP server can explicitly close the request. |
| |
| - pstats: Eric Raymond added a simple interactive statistics browser, |
| invoked when the module is run as a script. |
| |
| - locale: fixed a problem in format(). |
| |
| - webbrowser: made it work when the BROWSER environment variable has a |
| value like "/usr/bin/netscape". Made it auto-detect Konqueror for |
| KDE 2. Fixed some other nits. |
| |
| - unittest: changes to allow using a different exception than |
| AssertionError, and added a few more function aliases. Some other |
| small changes. |
| |
| - urllib, urllib2: fixed redirect problems and a coupleof other nits. |
| |
| - asynchat: fixed a critical bug in asynchat that slipped through the |
| 2.1b2 release. Fixed another rare bug. |
| |
| - Fix some unqualified except: clauses (always a bad code example). |
| |
| XML |
| |
| - pyexpat: new API get_version_string(). |
| |
| - Fixed some minidom bugs. |
| |
| Extensions |
| |
| - Fixed a core dump in _weakref. Removed the weakref.mapping() |
| function (it adds nothing to the API). |
| |
| - Rationalized the use of header files in the readline module, to make |
| it compile (albeit with some warnings) with the very recent readline |
| 4.2, without breaking for earlier versions. |
| |
| - Hopefully fixed a buffering problem in linuxaudiodev. |
| |
| - Attempted a fix to make the OpenSSL support in the socket module |
| work again with pre-0.9.5 versions of OpenSSL. |
| |
| Tests |
| |
| - Added a test case for asynchat and asyncore. |
| |
| - Removed coupling between tests where one test failing could break |
| another. |
| |
| Tools |
| |
| - Ping added an interactive help browser to pydoc, fixed some nits |
| in the rest of the pydoc code, and added some features to his |
| inspect module. |
| |
| - An updated python-mode.el version 4.1 which integrates Ken |
| Manheimer's pdbtrack.el. This makes debugging Python code via pdb |
| much nicer in XEmacs and Emacs. When stepping through your program |
| with pdb, in either the shell window or the *Python* window, the |
| source file and line will be tracked by an arrow. Very cool! |
| |
| - IDLE: syntax warnings in interactive mode are changed into errors. |
| |
| - Some improvements to Tools/webchecker (ignore some more URL types, |
| follow some more links). |
| |
| - Brought the Tools/compiler package up to date. |
| |
| |
| What's New in Python 2.1 beta 2? |
| ================================ |
| |
| (Unlisted are many fixed bugs, more documentation, etc.) |
| |
| Core language, builtins, and interpreter |
| |
| - The nested scopes work (enabled by "from __future__ import |
| nested_scopes") is completed; in particular, the future now extends |
| into code executed through exec, eval() and execfile(), and into the |
| interactive interpreter. |
| |
| - When calling a base class method (e.g. BaseClass.__init__(self)), |
| this is now allowed even if self is not strictly spoken a class |
| instance (e.g. when using metaclasses or the Don Beaudry hook). |
| |
| - Slice objects are now comparable but not hashable; this prevents |
| dict[:] from being accepted but meaningless. |
| |
| - Complex division is now calculated using less braindead algorithms. |
| This doesn't change semantics except it's more likely to give useful |
| results in extreme cases. Complex repr() now uses full precision |
| like float repr(). |
| |
| - sgmllib.py now calls handle_decl() for simple <!...> declarations. |
| |
| - It is illegal to assign to the name __debug__, which is set when the |
| interpreter starts. It is effectively a compile-time constant. |
| |
| - A warning will be issued if a global statement for a variable |
| follows a use or assignment of that variable. |
| |
| Standard library |
| |
| - unittest.py, a unit testing framework by Steve Purcell (PyUNIT, |
| inspired by JUnit), is now part of the standard library. You now |
| have a choice of two testing frameworks: unittest requires you to |
| write testcases as separate code, doctest gathers them from |
| docstrings. Both approaches have their advantages and |
| disadvantages. |
| |
| - A new module Tix was added, which wraps the Tix extension library |
| for Tk. With that module, it is not necessary to statically link |
| Tix with _tkinter, since Tix will be loaded with Tcl's "package |
| require" command. See Demo/tix/. |
| |
| - tzparse.py is now obsolete. |
| |
| - In gzip.py, the seek() and tell() methods are removed -- they were |
| non-functional anyway, and it's better if callers can test for their |
| existence with hasattr(). |
| |
| Python/C API |
| |
| - PyDict_Next(): it is now safe to call PyDict_SetItem() with a key |
| that's already in the dictionary during a PyDict_Next() iteration. |
| This used to fail occasionally when a dictionary resize operation |
| could be triggered that would rehash all the keys. All other |
| modifications to the dictionary are still off-limits during a |
| PyDict_Next() iteration! |
| |
| - New extended APIs related to passing compiler variables around. |
| |
| - New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass() |
| implement isinstance() and issubclass(). |
| |
| - Py_BuildValue() now has a "D" conversion to create a Python complex |
| number from a Py_complex C value. |
| |
| - Extensions types which support weak references must now set the |
| field allocated for the weak reference machinery to NULL themselves; |
| this is done to avoid the cost of checking each object for having a |
| weakly referencable type in PyObject_INIT(), since most types are |
| not weakly referencable. |
| |
| - PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for |
| free variables and cell variables to and from the frame's f_locals. |
| |
| - Variants of several functions defined in pythonrun.h have been added |
| to support the nested_scopes future statement. The variants all end |
| in Flags and take an extra argument, a PyCompilerFlags *; examples: |
| PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These |
| variants may be removed in Python 2.2, when nested scopes are |
| mandatory. |
| |
| Distutils |
| |
| - the sdist command now writes a PKG-INFO file, as described in PEP 241, |
| into the release tree. |
| |
| - several enhancements to the bdist_wininst command from Thomas Heller |
| (an uninstaller, more customization of the installer's display) |
| |
| - from Jack Jansen: added Mac-specific code to generate a dialog for |
| users to specify the command-line (because providing a command-line with |
| MacPython is awkward). Jack also made various fixes for the Mac |
| and the Metrowerks compiler. |
| |
| - added 'platforms' and 'keywords' to the set of metadata that can be |
| specified for a distribution. |
| |
| - applied patches from Jason Tishler to make the compiler class work with |
| Cygwin. |
| |
| |
| What's New in Python 2.1 beta 1? |
| ================================ |
| |
| Core language, builtins, and interpreter |
| |
| - Following an outcry from the community about the amount of code |
| broken by the nested scopes feature introduced in 2.1a2, we decided |
| to make this feature optional, and to wait until Python 2.2 (or at |
| least 6 months) to make it standard. The option can be enabled on a |
| per-module basis by adding "from __future__ import nested_scopes" at |
| the beginning of a module (before any other statements, but after |
| comments and an optional docstring). See PEP 236 (Back to the |
| __future__) for a description of the __future__ statement. PEP 227 |
| (Statically Nested Scopes) has been updated to reflect this change, |
| and to clarify the semantics in a number of endcases. |
| |
| - The nested scopes code, when enabled, has been hardened, and most |
| bugs and memory leaks in it have been fixed. |
| |
| - Compile-time warnings are now generated for a number of conditions |
| that will break or change in meaning when nested scopes are enabled: |
| |
| - Using "from...import *" or "exec" without in-clause in a function |
| scope that also defines a lambda or nested function with one or |
| more free (non-local) variables. The presence of the import* or |
| bare exec makes it impossible for the compiler to determine the |
| exact set of local variables in the outer scope, which makes it |
| impossible to determine the bindings for free variables in the |
| inner scope. To avoid the warning about import *, change it into |
| an import of explicitly name object, or move the import* statement |
| to the global scope; to avoid the warning about bare exec, use |
| exec...in... (a good idea anyway -- there's a possibility that |
| bare exec will be deprecated in the future). |
| |
| - Use of a global variable in a nested scope with the same name as a |
| local variable in a surrounding scope. This will change in |
| meaning with nested scopes: the name in the inner scope will |
| reference the variable in the outer scope rather than the global |
| of the same name. To avoid the warning, either rename the outer |
| variable, or use a global statement in the inner function. |
| |
| - An optional object allocator has been included. This allocator is |
| optimized for Python objects and should be faster and use less memory |
| than the standard system allocator. It is not enabled by default |
| because of possible thread safety problems. The allocator is only |
| protected by the Python interpreter lock and it is possible that some |
| extension modules require a thread safe allocator. The object |
| allocator can be enabled by providing the "--with-pymalloc" option to |
| configure. |
| |
| Standard library |
| |
| - pyexpat now detects the expat version if expat.h defines it. A |
| number of additional handlers are provided, which are only available |
| since expat 1.95. In addition, the methods SetParamEntityParsing and |
| GetInputContext of Parser objects are available with 1.95.x |
| only. Parser objects now provide the ordered_attributes and |
| specified_attributes attributes. A new module expat.model was added, |
| which offers a number of additional constants if 1.95.x is used. |
| |
| - xml.dom offers the new functions registerDOMImplementation and |
| getDOMImplementation. |
| |
| - xml.dom.minidom offers a toprettyxml method. A number of DOM |
| conformance issues have been resolved. In particular, Element now |
| has an hasAttributes method, and the handling of namespaces was |
| improved. |
| |
| - Ka-Ping Yee contributed two new modules: inspect.py, a module for |
| getting information about live Python code, and pydoc.py, a module |
| for interactively converting docstrings to HTML or text. |
| Tools/scripts/pydoc, which is now automatically installed into |
| <prefix>/bin, uses pydoc.py to display documentation; try running |
| "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that |
| lets you browse the module docstrings using a web browser. |
| |
| - New library module difflib.py, primarily packaging the SequenceMatcher |
| class at the heart of the popular ndiff.py file-comparison tool. |
| |
| - doctest.py (a framework for verifying Python code examples in docstrings) |
| is now part of the std library. |
| |
| Windows changes |
| |
| - A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a |
| small GUI that lets you browse the module docstrings using your |
| default web browser. |
| |
| - Import is now case-sensitive. PEP 235 (Import on Case-Insensitive |
| Platforms) is implemented. See |
| |
| http://python.sourceforge.net/peps/pep-0235.html |
| |
| for full details, especially the "Current Lower-Left Semantics" section. |
| The new Windows import rules are simpler than before: |
| |
| A. If the PYTHONCASEOK environment variable exists, same as |
| before: silently accept the first case-insensitive match of any |
| kind; raise ImportError if none found. |
| |
| B. Else search sys.path for the first case-sensitive match; raise |
| ImportError if none found. |
| |
| The same rules have been implented on other platforms with case- |
| insensitive but case-preserving filesystems too (including Cygwin, and |
| several flavors of Macintosh operating systems). |
| |
| - winsound module: Under Win9x, winsound.Beep() now attempts to simulate |
| what it's supposed to do (and does do under NT and 2000) via direct |
| port manipulation. It's unknown whether this will work on all systems, |
| but it does work on my Win98SE systems now and was known to be useless on |
| all Win9x systems before. |
| |
| - Build: Subproject _test (effectively) renamed to _testcapi. |
| |
| New platforms |
| |
| - 2.1 should compile and run out of the box under MacOS X, even using HFS+. |
| Thanks to Steven Majewski! |
| |
| - 2.1 should compile and run out of the box on Cygwin. Thanks to Jason |
| Tishler! |
| |
| - 2.1 contains new files and patches for RISCOS, thanks to Dietmar |
| Schwertberger! See RISCOS/README for more information -- it seems |
| that because of the bizarre filename conventions on RISCOS, no port |
| to that platform is easy. |
| |
| |
| What's New in Python 2.1 alpha 2? |
| ================================= |
| |
| Core language, builtins, and interpreter |
| |
| - Scopes nest. If a name is used in a function or class, but is not |
| local, the definition in the nearest enclosing function scope will |
| be used. One consequence of this change is that lambda statements |
| could reference variables in the namespaces where the lambda is |
| defined. In some unusual cases, this change will break code. |
| |
| In all previous version of Python, names were resolved in exactly |
| three namespaces -- the local namespace, the global namespace, and |
| the builtin namespace. According to this old definition, if a |
| function A is defined within a function B, the names bound in B are |
| not visible in A. The new rules make names bound in B visible in A, |
| unless A contains a name binding that hides the binding in B. |
| |
| Section 4.1 of the reference manual describes the new scoping rules |
| in detail. The test script in Lib/test/test_scope.py demonstrates |
| some of the effects of the change. |
| |
| The new rules will cause existing code to break if it defines nested |
| functions where an outer function has local variables with the same |
| name as globals or builtins used by the inner function. Example: |
| |
| def munge(str): |
| def helper(x): |
| return str(x) |
| if type(str) != type(''): |
| str = helper(str) |
| return str.strip() |
| |
| Under the old rules, the name str in helper() is bound to the |
| builtin function str(). Under the new rules, it will be bound to |
| the argument named str and an error will occur when helper() is |
| called. |
| |
| - The compiler will report a SyntaxError if "from ... import *" occurs |
| in a function or class scope. The language reference has documented |
| that this case is illegal, but the compiler never checked for it. |
| The recent introduction of nested scope makes the meaning of this |
| form of name binding ambiguous. In a future release, the compiler |
| may allow this form when there is no possibility of ambiguity. |
| |
| - repr(string) is easier to read, now using hex escapes instead of octal, |
| and using \t, \n and \r instead of \011, \012 and \015 (respectively): |
| |
| >>> "\texample \r\n" + chr(0) + chr(255) |
| '\texample \r\n\x00\xff' # in 2.1 |
| '\011example \015\012\000\377' # in 2.0 |
| |
| - Functions are now compared and hashed by identity, not by value, since |
| the func_code attribute is writable. |
| |
| - Weak references (PEP 205) have been added. This involves a few |
| changes in the core, an extension module (_weakref), and a Python |
| module (weakref). The weakref module is the public interface. It |
| includes support for "explicit" weak references, proxy objects, and |
| mappings with weakly held values. |
| |
| - A 'continue' statement can now appear in a try block within the body |
| of a loop. It is still not possible to use continue in a finally |
| clause. |
| |
| Standard library |
| |
| - mailbox.py now has a new class, PortableUnixMailbox which is |
| identical to UnixMailbox but uses a more portable scheme for |
| determining From_ separators. Also, the constructors for all the |
| classes in this module have a new optional `factory' argument, which |
| is a callable used when new message classes must be instantiated by |
| the next() method. |
| |
| - random.py is now self-contained, and offers all the functionality of |
| the now-deprecated whrandom.py. See the docs for details. random.py |
| also supports new functions getstate() and setstate(), for saving |
| and restoring the internal state of the generator; and jumpahead(n), |
| for quickly forcing the internal state to be the same as if n calls to |
| random() had been made. The latter is particularly useful for multi- |
| threaded programs, creating one instance of the random.Random() class for |
| each thread, then using .jumpahead() to force each instance to use a |
| non-overlapping segment of the full period. |
| |
| - random.py's seed() function is new. For bit-for-bit compatibility with |
| prior releases, use the whseed function instead. The new seed function |
| addresses two problems: (1) The old function couldn't produce more than |
| about 2**24 distinct internal states; the new one about 2**45 (the best |
| that can be done in the Wichmann-Hill generator). (2) The old function |
| sometimes produced identical internal states when passed distinct |
| integers, and there was no simple way to predict when that would happen; |
| the new one guarantees to produce distinct internal states for all |
| arguments in [0, 27814431486576L). |
| |
| - The socket module now supports raw packets on Linux. The socket |
| family is AF_PACKET. |
| |
| - test_capi.py is a start at running tests of the Python C API. The tests |
| are implemented by the new Modules/_testmodule.c. |
| |
| - A new extension module, _symtable, provides provisional access to the |
| internal symbol table used by the Python compiler. A higher-level |
| interface will be added on top of _symtable in a future release. |
| |
| - Removed the obsolete soundex module. |
| |
| - xml.dom.minidom now uses the standard DOM exceptions. Node supports |
| the isSameNode method; NamedNodeMap the get method. |
| |
| - xml.sax.expatreader supports the lexical handler property; it |
| generates comment, startCDATA, and endCDATA events. |
| |
| Windows changes |
| |
| - Build procedure: the zlib project is built in a different way that |
| ensures the zlib header files used can no longer get out of synch with |
| the zlib binary used. See PCbuild\readme.txt for details. Your old |
| zlib-related directories can be deleted; you'll need to download fresh |
| source for zlib and unpack it into a new directory. |
| |
| - Build: New subproject _test for the benefit of test_capi.py (see above). |
| |
| - Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent |
| interface to some Python compiler internals). |
| |
| - Build: Subproject ucnhash is gone, since the code was folded into the |
| unicodedata subproject. |
| |
| What's New in Python 2.1 alpha 1? |
| ================================= |
| |
| Core language, builtins, and interpreter |
| |
| - There is a new Unicode companion to the PyObject_Str() API |
| called PyObject_Unicode(). It behaves in the same way as the |
| former, but assures that the returned value is an Unicode object |
| (applying the usual coercion if necessary). |
| |
| - The comparison operators support "rich comparison overloading" (PEP |
| 207). C extension types can provide a rich comparison function in |
| the new tp_richcompare slot in the type object. The cmp() function |
| and the C function PyObject_Compare() first try the new rich |
| comparison operators before trying the old 3-way comparison. There |
| is also a new C API PyObject_RichCompare() (which also falls back on |
| the old 3-way comparison, but does not constrain the outcome of the |
| rich comparison to a Boolean result). |
| |
| The rich comparison function takes two objects (at least one of |
| which is guaranteed to have the type that provided the function) and |
| an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ, |
| Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python |
| object, which may be NotImplemented (in which case the tp_compare |
| slot function is used as a fallback, if defined). |
| |
| Classes can overload individual comparison operators by defining one |
| or more of the methods__lt__, __le__, __eq__, __ne__, __gt__, |
| __ge__. There are no explicit "reflected argument" versions of |
| these; instead, __lt__ and __gt__ are each other's reflection, |
| likewise for__le__ and __ge__; __eq__ and __ne__ are their own |
| reflection (similar at the C level). No other implications are |
| made; in particular, Python does not assume that == is the Boolean |
| inverse of !=, or that < is the Boolean inverse of >=. This makes |
| it possible to define types with partial orderings. |
| |
| Classes or types that want to implement (in)equality tests but not |
| the ordering operators (i.e. unordered types) should implement == |
| and !=, and raise an error for the ordering operators. |
| |
| It is possible to define types whose rich comparison results are not |
| Boolean; e.g. a matrix type might want to return a matrix of bits |
| for A < B, giving elementwise comparisons. Such types should ensure |
| that any interpretation of their value in a Boolean context raises |
| an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot |
| at the C level) to always raise an exception. |
| |
| - Complex numbers use rich comparisons to define == and != but raise |
| an exception for <, <=, > and >=. Unfortunately, this also means |
| that cmp() of two complex numbers raises an exception when the two |
| numbers differ. Since it is not mathematically meaningful to compare |
| complex numbers except for equality, I hope that this doesn't break |
| too much code. |
| |
| - The outcome of comparing non-numeric objects of different types is |
| not defined by the language, other than that it's arbitrary but |
| consistent (see the Reference Manual). An implementation detail changed |
| in 2.1a1 such that None now compares less than any other object. Code |
| relying on this new behavior (like code that relied on the previous |
| behavior) does so at its own risk. |
| |
| - Functions and methods now support getting and setting arbitrarily |
| named attributes (PEP 232). Functions have a new __dict__ |
| (a.k.a. func_dict) which hold the function attributes. Methods get |
| and set attributes on their underlying im_func. It is a TypeError |
| to set an attribute on a bound method. |
| |
| - The xrange() object implementation has been improved so that |
| xrange(sys.maxint) can be used on 64-bit platforms. There's still a |
| limitation that in this case len(xrange(sys.maxint)) can't be |
| calculated, but the common idiom "for i in xrange(sys.maxint)" will |
| work fine as long as the index i doesn't actually reach 2**31. |
| (Python uses regular ints for sequence and string indices; fixing |
| that is much more work.) |
| |
| - Two changes to from...import: |
| |
| 1) "from M import X" now works even if (after loading module M) |
| sys.modules['M'] is not a real module; it's basically a getattr() |
| operation with AttributeError exceptions changed into ImportError. |
| |
| 2) "from M import *" now looks for M.__all__ to decide which names to |
| import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but |
| filters out names starting with '_' as before. Whether or not |
| __all__ exists, there's no restriction on the type of M. |
| |
| - File objects have a new method, xreadlines(). This is the fastest |
| way to iterate over all lines in a file: |
| |
| for line in file.xreadlines(): |
| ...do something to line... |
| |
| See the xreadlines module (mentioned below) for how to do this for |
| other file-like objects. |
| |
| - Even if you don't use file.xreadlines(), you may expect a speedup on |
| line-by-line input. The file.readline() method has been optimized |
| quite a bit in platform-specific ways: on systems (like Linux) that |
| support flockfile(), getc_unlocked(), and funlockfile(), those are |
| used by default. On systems (like Windows) without getc_unlocked(), |
| a complicated (but still thread-safe) method using fgets() is used by |
| default. |
| |
| You can force use of the fgets() method by #define'ing |
| USE_FGETS_IN_GETLINE at build time (it may be faster than |
| getc_unlocked()). |
| |
| You can force fgets() not to be used by #define'ing |
| DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test |
| test_bufio.py fails -- and let us know if it does!). |
| |
| - In addition, the fileinput module, while still slower than the other |
| methods on most platforms, has been sped up too, by using |
| file.readlines(sizehint). |
| |
| - Support for run-time warnings has been added, including a new |
| command line option (-W) to specify the disposition of warnings. |
| See the description of the warnings module below. |
| |
| - Extensive changes have been made to the coercion code. This mostly |
| affects extension modules (which can now implement mixed-type |
| numerical operators without having to use coercion), but |
| occasionally, in boundary cases the coercion semantics have changed |
| subtly. Since this was a terrible gray area of the language, this |
| is considered an improvement. Also note that __rcmp__ is no longer |
| supported -- instead of calling __rcmp__, __cmp__ is called with |
| reflected arguments. |
| |
| - In connection with the coercion changes, a new built-in singleton |
| object, NotImplemented is defined. This can be returned for |
| operations that wish to indicate they are not implemented for a |
| particular combination of arguments. From C, this is |
| Py_NotImplemented. |
| |
| - The interpreter accepts now bytecode files on the command line even |
| if they do not have a .pyc or .pyo extension. On Linux, after executing |
| |
| import imp,sys,string |
| magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"") |
| reg = ':pyc:M::%s::%s:' % (magic, sys.executable) |
| open("/proc/sys/fs/binfmt_misc/register","wb").write(reg) |
| |
| any byte code file can be used as an executable (i.e. as an argument |
| to execve(2)). |
| |
| - %[xXo] formats of negative Python longs now produce a sign |
| character. In 1.6 and earlier, they never produced a sign, |
| and raised an error if the value of the long was too large |
| to fit in a Python int. In 2.0, they produced a sign if and |
| only if too large to fit in an int. This was inconsistent |
| across platforms (because the size of an int varies across |
| platforms), and inconsistent with hex() and oct(). Example: |
| |
| >>> "%x" % -0x42L |
| '-42' # in 2.1 |
| 'ffffffbe' # in 2.0 and before, on 32-bit machines |
| >>> hex(-0x42L) |
| '-0x42L' # in all versions of Python |
| |
| The behavior of %d formats for negative Python longs remains |
| the same as in 2.0 (although in 1.6 and before, they raised |
| an error if the long didn't fit in a Python int). |
| |
| %u formats don't make sense for Python longs, but are allowed |
| and treated the same as %d in 2.1. In 2.0, a negative long |
| formatted via %u produced a sign if and only if too large to |
| fit in an int. In 1.6 and earlier, a negative long formatted |
| via %u raised an error if it was too big to fit in an int. |
| |
| - Dictionary objects have an odd new method, popitem(). This removes |
| an arbitrary item from the dictionary and returns it (in the form of |
| a (key, value) pair). This can be useful for algorithms that use a |
| dictionary as a bag of "to do" items and repeatedly need to pick one |
| item. Such algorithms normally end up running in quadratic time; |
| using popitem() they can usually be made to run in linear time. |
| |
| Standard library |
| |
| - In the time module, the time argument to the functions strftime, |
| localtime, gmtime, asctime and ctime is now optional, defaulting to |
| the current time (in the local timezone). |
| |
| - The ftplib module now defaults to passive mode, which is deemed a |
| more useful default given that clients are often inside firewalls |
| these days. Note that this could break if ftplib is used to connect |
| to a *server* that is inside a firewall, from outside; this is |
| expected to be a very rare situation. To fix that, you can call |
| ftp.set_pasv(0). |
| |
| - The module site now treats .pth files not only for path configuration, |
| but also supports extensions to the initialization code: Lines starting |
| with import are executed. |
| |
| - There's a new module, warnings, which implements a mechanism for |
| issuing and filtering warnings. There are some new built-in |
| exceptions that serve as warning categories, and a new command line |
| option, -W, to control warnings (e.g. -Wi ignores all warnings, -We |
| turns warnings into errors). warnings.warn(message[, category]) |
| issues a warning message; this can also be called from C as |
| PyErr_Warn(category, message). |
| |
| - A new module xreadlines was added. This exports a single factory |
| function, xreadlines(). The intention is that this code is the |
| absolutely fastest way to iterate over all lines in an open |
| file(-like) object: |
| |
| import xreadlines |
| for line in xreadlines.xreadlines(file): |
| ...do something to line... |
| |
| This is equivalent to the previous the speed record holder using |
| file.readlines(sizehint). Note that if file is a real file object |
| (as opposed to a file-like object), this is equivalent: |
| |
| for line in file.xreadlines(): |
| ...do something to line... |
| |
| - The bisect module has new functions bisect_left, insort_left, |
| bisect_right and insort_right. The old names bisect and insort |
| are now aliases for bisect_right and insort_right. XXX_right |
| and XXX_left methods differ in what happens when the new element |
| compares equal to one or more elements already in the list: the |
| XXX_left methods insert to the left, the XXX_right methods to the |
| right. Code that doesn't care where equal elements end up should |
| continue to use the old, short names ("bisect" and "insort"). |
| |
| - The new curses.panel module wraps the panel library that forms part |
| of SYSV curses and ncurses. Contributed by Thomas Gellekum. |
| |
| - The SocketServer module now sets the allow_reuse_address flag by |
| default in the TCPServer class. |
| |
| - A new function, sys._getframe(), returns the stack frame pointer of |
| the caller. This is intended only as a building block for |
| higher-level mechanisms such as string interpolation. |
| |
| - The pyexpat module supports a number of new handlers, which are |
| available only in expat 1.2. If invocation of a callback fails, it |
| will report an additional frame in the traceback. Parser objects |
| participate now in garbage collection. If expat reports an unknown |
| encoding, pyexpat will try to use a Python codec; that works only |
| for single-byte charsets. The parser type objects is exposed as |
| XMLParserObject. |
| |
| - xml.dom now offers standard definitions for symbolic node type and |
| exception code constants, and a hierarchy of DOM exceptions. minidom |
| was adjusted to use them. |
| |
| - The conformance of xml.dom.minidom to the DOM specification was |
| improved. It detects a number of additional error cases; the |
| previous/next relationship works even when the tree is modified; |
| Node supports the normalize() method; NamedNodeMap, DocumentType and |
| DOMImplementation classes were added; Element supports the |
| hasAttribute and hasAttributeNS methods; and Text supports the splitText |
| method. |
| |
| Build issues |
| |
| - For Unix (and Unix-compatible) builds, configuration and building of |
| extension modules is now greatly automated. Rather than having to |
| edit the Modules/Setup file to indicate which modules should be |
| built and where their include files and libraries are, a |
| distutils-based setup.py script now takes care of building most |
| extension modules. All extension modules built this way are built |
| as shared libraries. Only a few modules that must be linked |
| statically are still listed in the Setup file; you won't need to |
| edit their configuration. |
| |
| - Python should now build out of the box on Cygwin. If it doesn't, |
| mail to Jason Tishler (jlt63 at users.sourceforge.net). |
| |
| - Python now always uses its own (renamed) implementation of getopt() |
| -- there's too much variation among C library getopt() |
| implementations. |
| |
| - C++ compilers are better supported; the CXX macro is always set to a |
| C++ compiler if one is found. |
| |
| Windows changes |
| |
| - select module: By default under Windows, a select() call |
| can specify no more than 64 sockets. Python now boosts |
| this Microsoft default to 512. If you need even more than |
| that, see the MS docs (you'll need to #define FD_SETSIZE |
| and recompile Python from source). |
| |
| - Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3 |
| subdirectory is no more! |
| |
| |
| What's New in Python 2.0? |
| ========================= |
| |
| Below is a list of all relevant changes since release 1.6. Older |
| changes are in the file HISTORY. If you are making the jump directly |
| from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the |
| HISTORY file! Many important changes listed there. |
| |
| Alternatively, a good overview of the changes between 1.5.2 and 2.0 is |
| the document "What's New in Python 2.0" by Kuchling and Moshe Zadka: |
| http://starship.python.net/crew/amk/python/writing/new-python/. |
| |
| --Guido van Rossum (home page: http://www.pythonlabs.com/~guido/) |
| |
| ====================================================================== |
| |
| What's new in 2.0 (since release candidate 1)? |
| ============================================== |
| |
| Standard library |
| |
| - The copy_reg module was modified to clarify its intended use: to |
| register pickle support for extension types, not for classes. |
| pickle() will raise a TypeError if it is passed a class. |
| |
| - Fixed a bug in gettext's "normalize and expand" code that prevented |
| it from finding an existing .mo file. |
| |
| - Restored support for HTTP/0.9 servers in httplib. |
| |
| - The math module was changed to stop raising OverflowError in case of |
| underflow, and return 0 instead in underflow cases. Whether Python |
| used to raise OverflowError in case of underflow was platform- |
| dependent (it did when the platform math library set errno to ERANGE |
| on underflow). |
| |
| - Fixed a bug in StringIO that occurred when the file position was not |
| at the end of the file and write() was called with enough data to |
| extend past the end of the file. |
| |
| - Fixed a bug that caused Tkinter error messages to get lost on |
| Windows. The bug was fixed by replacing direct use of |
| interp->result with Tcl_GetStringResult(interp). |
| |
| - Fixed bug in urllib2 that caused it to fail when it received an HTTP |
| redirect response. |
| |
| - Several changes were made to distutils: Some debugging code was |
| removed from util. Fixed the installer used when an external zip |
| program (like WinZip) is not found; the source code for this |
| installer is in Misc/distutils. check_lib() was modified to behave |
| more like AC_CHECK_LIB by add other_libraries() as a parameter. The |
| test for whether installed modules are on sys.path was changed to |
| use both normcase() and normpath(). |
| |
| - Several minor bugs were fixed in the xml package (the minidom, |
| pulldom, expatreader, and saxutils modules). |
| |
| - The regression test driver (regrtest.py) behavior when invoked with |
| -l changed: It now reports a count of objects that are recognized as |
| garbage but not freed by the garbage collector. |
| |
| - The regression test for the math module was changed to test |
| exceptional behavior when the test is run in verbose mode. Python |
| cannot yet guarantee consistent exception behavior across platforms, |
| so the exception part of test_math is run only in verbose mode, and |
| may fail on your platform. |
| |
| Internals |
| |
| - PyOS_CheckStack() has been disabled on Win64, where it caused |
| test_sre to fail. |
| |
| Build issues |
| |
| - Changed compiler flags, so that gcc is always invoked with -Wall and |
| -Wstrict-prototypes. Users compiling Python with GCC should see |
| exactly one warning, except if they have passed configure the |
| --with-pydebug flag. The expected warning is for getopt() in |
| Modules/main.c. This warning will be fixed for Python 2.1. |
| |
| - Fixed configure to add -threads argument during linking on OSF1. |
| |
| Tools and other miscellany |
| |
| - The compiler in Tools/compiler was updated to support the new |
| language features introduced in 2.0: extended print statement, list |
| comprehensions, and augmented assignments. The new compiler should |
| also be backwards compatible with Python 1.5.2; the compiler will |
| always generate code for the version of the interpreter it runs |
| under. |
| |
| What's new in 2.0 release candidate 1 (since beta 2)? |
| ===================================================== |
| |
| What is release candidate 1? |
| |
| We believe that release candidate 1 will fix all known bugs that we |
| intend to fix for the 2.0 final release. This release should be a bit |
| more stable than the previous betas. We would like to see even more |
| widespread testing before the final release, so we are producing this |
| release candidate. The final release will be exactly the same unless |
| any show-stopping (or brown bag) bugs are found by testers of the |
| release candidate. |
| |
| All the changes since the last beta release are bug fixes or changes |
| to support building Python for specific platforms. |
| |
| Core language, builtins, and interpreter |
| |
| - A bug that caused crashes when __coerce__ was used with augmented |
| assignment, e.g. +=, was fixed. |
| |
| - Raise ZeroDivisionError when raising zero to a negative number, |
| e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin |
| power operator and the result of math.pow(0.0, -2.0) will vary by |
| platform. On Linux, it raises a ValueError. |
| |
| - A bug in Unicode string interpolation was fixed that occasionally |
| caused errors with formats including "%%". For example, the |
| following expression "%% %s" % u"abc" no longer raises a TypeError. |
| |
| - Compilation of deeply nested expressions raises MemoryError instead |
| of SyntaxError, e.g. eval("[" * 50 + "]" * 50). |
| |
| - In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode, |
| rendering them useless. They are now written in binary mode again. |
| |
| Standard library |
| |
| - Keyword arguments are now accepted for most pattern and match object |
| methods in SRE, the standard regular expression engine. |
| |
| - In SRE, fixed error with negative lookahead and lookbehind that |
| manifested itself as a runtime error in patterns like "(?<!abc)(def)". |
| |
| - Several bugs in the Unicode handling and error handling in _tkinter |
| were fixed. |
| |
| - Fix memory management errors in Merge() and Tkapp_Call() routines. |
| |
| - Several changes were made to cStringIO to make it compatible with |
| the file-like object interface and with StringIO. If operations are |
| performed on a closed object, an exception is raised. The truncate |
| method now accepts a position argument and readline accepts a size |
| argument. |
| |
| - There were many changes made to the linuxaudiodev module and its |
| test suite; as a result, a short, unexpected audio sample should now |
| play when the regression test is run. |
| |
| Note that this module is named poorly, because it should work |
| correctly on any platform that supports the Open Sound System |
| (OSS). |
| |
| The module now raises exceptions when errors occur instead of |
| crashing. It also defines the AFMT_A_LAW format (logarithmic A-law |
| audio) and defines a getptr() method that calls the |
| SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide. |
| |
| - The library_version attribute, introduced in an earlier beta, was |
| removed because it can not be supported with early versions of the C |
| readline library, which provides no way to determine the version at |
| compile-time. |
| |
| - The binascii module is now enabled on Win64. |
| |
| - tokenize.py no longer suffers "recursion depth" errors when parsing |
| programs with very long string literals. |
| |
| Internals |
| |
| - Fixed several buffer overflow vulnerabilities in calculate_path(), |
| which is called when the interpreter starts up to determine where |
| the standard library is installed. These vulnerabilities affect all |
| previous versions of Python and can be exploited by setting very |
| long values for PYTHONHOME or argv[0]. The risk is greatest for a |
| setuid Python script, although use of the wrapper in |
| Misc/setuid-prog.c will eliminate the vulnerability. |
| |
| - Fixed garbage collection bugs in instance creation that were |
| triggered when errors occurred during initialization. The solution, |
| applied in cPickle and in PyInstance_New(), is to call |
| PyObject_GC_Init() after the initialization of the object's |
| container attributes is complete. |
| |
| - pyexpat adds definitions of PyModule_AddStringConstant and |
| PyModule_AddObject if the Python version is less than 2.0, which |
| provides compatibility with PyXML on Python 1.5.2. |
| |
| - If the platform has a bogus definition for LONG_BIT (the number of |
| bits in a long), an error will be reported at compile time. |
| |
| - Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage |
| collection crashes and possibly other, unreported crashes. |
| |
| - Fixed a memory leak in _PyUnicode_Fini(). |
| |
| Build issues |
| |
| - configure now accepts a --with-suffix option that specifies the |
| executable suffix. This is useful for builds on Cygwin and Mac OS |
| X, for example. |
| |
| - The mmap.PAGESIZE constant is now initialized using sysconf when |
| possible, which eliminates a dependency on -lucb for Reliant UNIX. |
| |
| - The md5 file should now compile on all platforms. |
| |
| - The select module now compiles on platforms that do not define |
| POLLRDNORM and related constants. |
| |
| - Darwin (Mac OS X): Initial support for static builds on this |
| platform. |
| |
| - BeOS: A number of changes were made to the build and installation |
| process. ar-fake now operates on a directory of object files. |
| dl_export.h is gone, and its macros now appear on the mwcc command |
| line during build on PPC BeOS. |
| |
| - Platform directory in lib/python2.0 is "plat-beos5" (or |
| "plat-beos4", if building on BeOS 4.5), rather than "plat-beos". |
| |
| - Cygwin: Support for shared libraries, Tkinter, and sockets. |
| |
| - SunOS 4.1.4_JL: Fix test for directory existence in configure. |
| |
| Tools and other miscellany |
| |
| - Removed debugging prints from main used with freeze. |
| |
| - IDLE auto-indent no longer crashes when it encounters Unicode |
| characters. |
| |
| What's new in 2.0 beta 2 (since beta 1)? |
| ======================================== |
| |
| Core language, builtins, and interpreter |
| |
| - Add support for unbounded ints in %d,i,u,x,X,o formats; for example |
| "%d" % 2L**64 == "18446744073709551616". |
| |
| - Add -h and -V command line options to print the usage message and |
| Python version number and exit immediately. |
| |
| - eval() and exec accept Unicode objects as code parameters. |
| |
| - getattr() and setattr() now also accept Unicode objects for the |
| attribute name, which are converted to strings using the default |
| encoding before lookup. |
| |
| - Multiplication on string and Unicode now does proper bounds |
| checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated |
| string is too long." |
| |
| - Better error message when continue is found in try statement in a |
| loop. |
| |
| |
| Standard library and extensions |
| |
| - socket module: the OpenSSL code now adds support for RAND_status() |
| and EGD (Entropy Gathering Device). |
| |
| - array: reverse() method of array now works. buffer_info() now does |
| argument checking; it still takes no arguments. |
| |
| - asyncore/asynchat: Included most recent version from Sam Rushing. |
| |
| - cgi: Accept '&' or ';' as separator characters when parsing form data. |
| |
| - CGIHTTPServer: Now works on Windows (and perhaps even Mac). |
| |
| - ConfigParser: When reading the file, options spelled in upper case |
| letters are now correctly converted to lowercase. |
| |
| - copy: Copy Unicode objects atomically. |
| |
| - cPickle: Fail gracefully when copy_reg can't be imported. |
| |
| - cStringIO: Implemented readlines() method. |
| |
| - dbm: Add get() and setdefault() methods to dbm object. Add constant |
| `library' to module that names the library used. Added doc strings |
| and method names to error messages. Uses configure to determine |
| which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is |
| now available options. |
| |
| - distutils: Update to version 0.9.3. |
| |
| - dl: Add several dl.RTLD_ constants. |
| |
| - fpectl: Now supported on FreeBSD. |
| |
| - gc: Add DEBUG_SAVEALL option. When enabled all garbage objects |
| found by the collector will be saved in gc.garbage. This is useful |
| for debugging a program that creates reference cycles. |
| |
| - httplib: Three changes: Restore support for set_debuglevel feature |
| of HTTP class. Do not close socket on zero-length response. Do not |
| crash when server sends invalid content-length header. |
| |
| - mailbox: Mailbox class conforms better to qmail specifications. |
| |
| - marshal: When reading a short, sign-extend on platforms where shorts |
| are bigger than 16 bits. When reading a long, repair the unportable |
| sign extension that was being done for 64-bit machines. (It assumed |
| that signed right shift sign-extends.) |
| |
| - operator: Add contains(), invert(), __invert__() as aliases for |
| __contains__(), inv(), and __inv__() respectively. |
| |
| - os: Add support for popen2() and popen3() on all platforms where |
| fork() exists. (popen4() is still in the works.) |
| |
| - os: (Windows only:) Add startfile() function that acts like double- |
| clicking on a file in Explorer (or passing the file name to the |
| DOS "start" command). |
| |
| - os.path: (Windows, DOS:) Treat trailing colon correctly in |
| os.path.join. os.path.join("a:", "b") yields "a:b". |
| |
| - pickle: Now raises ValueError when an invalid pickle that contains |
| a non-string repr where a string repr was expected. This behavior |
| matches cPickle. |
| |
| - posixfile: Remove broken __del__() method. |
| |
| - py_compile: support CR+LF line terminators in source file. |
| |
| - readline: Does not immediately exit when ^C is hit when readline and |
| threads are configured. Adds definition of rl_library_version. (The |
| latter addition requires GNU readline 2.2 or later.) |
| |
| - rfc822: Domain literals returned by AddrlistClass method |
| getdomainliteral() are now properly wrapped in brackets. |
| |
| - site: sys.setdefaultencoding() should only be called in case the |
| standard default encoding ("ascii") is changed. This saves quite a |
| few cycles during startup since the first call to |
| setdefaultencoding() will initialize the codec registry and the |
| encodings package. |
| |
| - socket: Support for size hint in readlines() method of object returned |
| by makefile(). |
| |
| - sre: Added experimental expand() method to match objects. Does not |
| use buffer interface on Unicode strings. Does not hang if group id |
| is followed by whitespace. |
| |
| - StringIO: Size hint in readlines() is now supported as documented. |
| |
| - struct: Check ranges for bytes and shorts. |
| |
| - urllib: Improved handling of win32 proxy settings. Fixed quote and |
| quote_plus functions so that the always encode a comma. |
| |
| - Tkinter: Image objects are now guaranteed to have unique ids. Set |
| event.delta to zero if Tk version doesn't support mousewheel. |
| Removed some debugging prints. |
| |
| - UserList: now implements __contains__(). |
| |
| - webbrowser: On Windows, use os.startfile() instead of os.popen(), |
| which works around a bug in Norton AntiVirus 2000 that leads directly |
| to a Blue Screen freeze. |
| |
| - xml: New version detection code allows PyXML to override standard |
| XML package if PyXML version is greater than 0.6.1. |
| |
| - xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom |
| (conventional DOM), and xml.dom.pulldom, which allows building the DOM |
| tree only for nodes which are sufficiently interesting to a specific |
| application. Does not provide the HTML-specific extensions. Still |
| undocumented. |
| |
| - xml.sax: SAX 2 support for Python, including all the handler |
| interfaces needed to process XML 1.0 compliant XML. Some |
| documentation is already available. |
| |
| - pyexpat: Renamed to xml.parsers.expat since this is part of the new, |
| packagized XML support. |
| |
| |
| C API |
| |
| - Add three new convenience functions for module initialization -- |
| PyModule_AddObject(), PyModule_AddIntConstant(), and |
| PyModule_AddStringConstant(). |
| |
| - Cleaned up definition of NULL in C source code; all definitions were |
| removed and add #error to Python.h if NULL isn't defined after |
| #include of stdio.h. |
| |
| - Py_PROTO() macros that were removed in 2.0b1 have been restored for |
| backwards compatibility (at the source level) with old extensions. |
| |
| - A wrapper API was added for signal() and sigaction(). Instead of |
| either function, always use PyOS_getsig() to get a signal handler |
| and PyOS_setsig() to set one. A new convenience typedef |
| PyOS_sighandler_t is defined for the type of signal handlers. |
| |
| - Add PyString_AsStringAndSize() function that provides access to the |
| internal data buffer and size of a string object -- or the default |
| encoded version of a Unicode object. |
| |
| - PyString_Size() and PyString_AsString() accept Unicode objects. |
| |
| - The standard header <limits.h> is now included by Python.h (if it |
| exists). INT_MAX and LONG_MAX will always be defined, even if |
| <limits.h> is not available. |
| |
| - PyFloat_FromString takes a second argument, pend, that was |
| effectively useless. It is now officially useless but preserved for |
| backwards compatibility. If the pend argument is not NULL, *pend is |
| set to NULL. |
| |
| - PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects |
| for the attribute name. See note on getattr() above. |
| |
| - A few bug fixes to argument processing for Unicode. |
| PyArg_ParseTupleAndKeywords() now accepts "es#" and "es". |
| PyArg_Parse() special cases "s#" for Unicode objects; it returns a |
| pointer to the default encoded string data instead of to the raw |
| UTF-16. |
| |
| - Py_BuildValue accepts B format (for bgen-generated code). |
| |
| |
| Internals |
| |
| - On Unix, fix code for finding Python installation directory so that |
| it works when argv[0] is a relative path. |
| |
| - Added a true unicode_internal_encode() function and fixed the |
| unicode_internal_decode function() to support Unicode objects directly |
| rather than by generating a copy of the object. |
| |
| - Several of the internal Unicode tables are much smaller now, and |
| the source code should be much friendlier to weaker compilers. |
| |
| - In the garbage collector: Fixed bug in collection of tuples. Fixed |
| bug that caused some instances to be removed from the container set |
| while they were still live. Fixed parsing in gc.set_debug() for |
| platforms where sizeof(long) > sizeof(int). |
| |
| - Fixed refcount problem in instance deallocation that only occurred |
| when Py_REF_DEBUG was defined and Py_TRACE_REFS was not. |
| |
| - On Windows, getpythonregpath is now protected against null data in |
| registry key. |
| |
| - On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race |
| condition. |
| |
| |
| Build and platform-specific issues |
| |
| - Better support of GNU Pth via --with-pth configure option. |
| |
| - Python/C API now properly exposed to dynamically-loaded extension |
| modules on Reliant UNIX. |
| |
| - Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c: |
| Don't define MS_SYNC to be zero when it is undefined. Added missing |
| prototypes in posixmodule.c. |
| |
| - Improved support for HP-UX build. Threads should now be correctly |
| configured (on HP-UX 10.20 and 11.00). |
| |
| - Fix largefile support on older NetBSD systems and OpenBSD by adding |
| define for TELL64. |
| |
| |
| Tools and other miscellany |
| |
| - ftpmirror: Call to main() is wrapped in if __name__ == "__main__". |
| |
| - freeze: The modulefinder now works with 2.0 opcodes. |
| |
| - IDLE: |
| Move hackery of sys.argv until after the Tk instance has been |
| created, which allows the application-specific Tkinter |
| initialization to be executed if present; also pass an explicit |
| className parameter to the Tk() constructor. |
| |
| |
| What's new in 2.0 beta 1? |
| ========================= |
| |
| Source Incompatibilities |
| ------------------------ |
| |
| None. Note that 1.6 introduced several incompatibilities with 1.5.2, |
| such as single-argument append(), connect() and bind(), and changes to |
| str(long) and repr(float). |
| |
| |
| Binary Incompatibilities |
| ------------------------ |
| |
| - Third party extensions built for Python 1.5.x or 1.6 cannot be used |
| with Python 2.0; these extensions will have to be rebuilt for Python |
| 2.0. |
| |
| - On Windows, attempting to import a third party extension built for |
| Python 1.5.x or 1.6 results in an immediate crash; there's not much we |
| can do about this. Check your PYTHONPATH environment variable! |
| |
| - Python bytecode files (*.pyc and *.pyo) are not compatible between |
| releases. |
| |
| |
| Overview of Changes Since 1.6 |
| ----------------------------- |
| |
| There are many new modules (including brand new XML support through |
| the xml package, and i18n support through the gettext module); a list |
| of all new modules is included below. Lots of bugs have been fixed. |
| |
| The process for making major new changes to the language has changed |
| since Python 1.6. Enhancements must now be documented by a Python |
| Enhancement Proposal (PEP) before they can be accepted. |
| |
| There are several important syntax enhancements, described in more |
| detail below: |
| |
| - Augmented assignment, e.g. x += 1 |
| |
| - List comprehensions, e.g. [x**2 for x in range(10)] |
| |
| - Extended import statement, e.g. import Module as Name |
| |
| - Extended print statement, e.g. print >> file, "Hello" |
| |
| Other important changes: |
| |
| - Optional collection of cyclical garbage |
| |
| Python Enhancement Proposal (PEP) |
| --------------------------------- |
| |
| PEP stands for Python Enhancement Proposal. A PEP is a design |
| document providing information to the Python community, or describing |
| a new feature for Python. The PEP should provide a concise technical |
| specification of the feature and a rationale for the feature. |
| |
| We intend PEPs to be the primary mechanisms for proposing new |
| features, for collecting community input on an issue, and for |
| documenting the design decisions that have gone into Python. The PEP |
| author is responsible for building consensus within the community and |
| documenting dissenting opinions. |
| |
| The PEPs are available at http://python.sourceforge.net/peps/. |
| |
| Augmented Assignment |
| -------------------- |
| |
| This must have been the most-requested feature of the past years! |
| Eleven new assignment operators were added: |
| |
| += -= *= /= %= **= <<= >>= &= ^= |= |
| |
| For example, |
| |
| A += B |
| |
| is similar to |
| |
| A = A + B |
| |
| except that A is evaluated only once (relevant when A is something |
| like dict[index].attr). |
| |
| However, if A is a mutable object, A may be modified in place. Thus, |
| if A is a number or a string, A += B has the same effect as A = A+B |
| (except A is only evaluated once); but if a is a list, A += B has the |
| same effect as A.extend(B)! |
| |
| Classes and built-in object types can override the new operators in |
| order to implement the in-place behavior; the not-in-place behavior is |
| used automatically as a fallback when an object doesn't implement the |
| in-place behavior. For classes, the method name is derived from the |
| method name for the corresponding not-in-place operator by inserting |
| an 'i' in front of the name, e.g. __iadd__ implements in-place |
| __add__. |
| |
| Augmented assignment was implemented by Thomas Wouters. |
| |
| |
| List Comprehensions |
| ------------------- |
| |
| This is a flexible new notation for lists whose elements are computed |
| from another list (or lists). The simplest form is: |
| |
| [<expression> for <variable> in <sequence>] |
| |
| For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9]. |
| This is more efficient than a for loop with a list.append() call. |
| |
| You can also add a condition: |
| |
| [<expression> for <variable> in <sequence> if <condition>] |
| |
| For example, [w for w in words if w == w.lower()] would yield the list |
| of words that contain no uppercase characters. This is more efficient |
| than a for loop with an if statement and a list.append() call. |
| |
| You can also have nested for loops and more than one 'if' clause. For |
| example, here's a function that flattens a sequence of sequences:: |
| |
| def flatten(seq): |
| return [x for subseq in seq for x in subseq] |
| |
| flatten([[0], [1,2,3], [4,5], [6,7,8,9], []]) |
| |
| This prints |
| |
| [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
| |
| List comprehensions originated as a patch set from Greg Ewing; Skip |
| Montanaro and Thomas Wouters also contributed. Described by PEP 202. |
| |
| |
| Extended Import Statement |
| ------------------------- |
| |
| Many people have asked for a way to import a module under a different |
| name. This can be accomplished like this: |
| |
| import foo |
| bar = foo |
| del foo |
| |
| but this common idiom gets old quickly. A simple extension of the |
| import statement now allows this to be written as follows: |
| |
| import foo as bar |
| |
| There's also a variant for 'from ... import': |
| |
| from foo import bar as spam |
| |
| This also works with packages; e.g. you can write this: |
| |
| import test.regrtest as regrtest |
| |
| Note that 'as' is not a new keyword -- it is recognized only in this |
| context (this is only possible because the syntax for the import |
| statement doesn't involve expressions). |
| |
| Implemented by Thomas Wouters. Described by PEP 221. |
| |
| |
| Extended Print Statement |
| ------------------------ |
| |
| Easily the most controversial new feature, this extension to the print |
| statement adds an option to make the output go to a different file |
| than the default sys.stdout. |
| |
| For example, to write an error message to sys.stderr, you can now |
| write: |
| |
| print >> sys.stderr, "Error: bad dog!" |
| |
| As a special feature, if the expression used to indicate the file |
| evaluates to None, the current value of sys.stdout is used. Thus: |
| |
| print >> None, "Hello world" |
| |
| is equivalent to |
| |
| print "Hello world" |
| |
| Design and implementation by Barry Warsaw. Described by PEP 214. |
| |
| |
| Optional Collection of Cyclical Garbage |
| --------------------------------------- |
| |
| Python is now equipped with a garbage collector that can hunt down |
| cyclical references between Python objects. It's no replacement for |
| reference counting; in fact, it depends on the reference counts being |
| correct, and decides that a set of objects belong to a cycle if all |
| their reference counts can be accounted for from their references to |
| each other. This devious scheme was first proposed by Eric Tiedemann, |
| and brought to implementation by Neil Schemenauer. |
| |
| There's a module "gc" that lets you control some parameters of the |
| garbage collection. There's also an option to the configure script |
| that lets you enable or disable the garbage collection. In 2.0b1, |
| it's on by default, so that we (hopefully) can collect decent user |
| experience with this new feature. There are some questions about its |
| performance. If it proves to be too much of a problem, we'll turn it |
| off by default in the final 2.0 release. |
| |
| |
| Smaller Changes |
| --------------- |
| |
| A new function zip() was added. zip(seq1, seq2, ...) is equivalent to |
| map(None, seq1, seq2, ...) when the sequences have the same length; |
| i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When |
| the lists are not all the same length, the shortest list wins: |
| zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201. |
| |
| sys.version_info is a tuple (major, minor, micro, level, serial). |
| |
| Dictionaries have an odd new method, setdefault(key, default). |
| dict.setdefault(key, default) returns dict[key] if it exists; if not, |
| it sets dict[key] to default and returns that value. Thus: |
| |
| dict.setdefault(key, []).append(item) |
| |
| does the same work as this common idiom: |
| |
| if not dict.has_key(key): |
| dict[key] = [] |
| dict[key].append(item) |
| |
| There are two new variants of SyntaxError that are raised for |
| indentation-related errors: IndentationError and TabError. |
| |
| Changed \x to consume exactly two hex digits; see PEP 223. Added \U |
| escape that consumes exactly eight hex digits. |
| |
| The limits on the size of expressions and file in Python source code |
| have been raised from 2**16 to 2**32. Previous versions of Python |
| were limited because the maximum argument size the Python VM accepted |
| was 2**16. This limited the size of object constructor expressions, |
| e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This |
| limit was raised thanks to a patch by Charles Waldman that effectively |
| fixes the problem. It is now much more likely that you will be |
| limited by available memory than by an arbitrary limit in Python. |
| |
| The interpreter's maximum recursion depth can be modified by Python |
| programs using sys.getrecursionlimit and sys.setrecursionlimit. This |
| limit is the maximum number of recursive calls that can be made by |
| Python code. The limit exists to prevent infinite recursion from |
| overflowing the C stack and causing a core dump. The default value is |
| 1000. The maximum safe value for a particular platform can be found |
| by running Misc/find_recursionlimit.py. |
| |
| New Modules and Packages |
| ------------------------ |
| |
| atexit - for registering functions to be called when Python exits. |
| |
| imputil - Greg Stein's alternative API for writing custom import |
| hooks. |
| |
| pyexpat - an interface to the Expat XML parser, contributed by Paul |
| Prescod. |
| |
| xml - a new package with XML support code organized (so far) in three |
| subpackages: xml.dom, xml.sax, and xml.parsers. Describing these |
| would fill a volume. There's a special feature whereby a |
| user-installed package named _xmlplus overrides the standard |
| xmlpackage; this is intended to give the XML SIG a hook to distribute |
| backwards-compatible updates to the standard xml package. |
| |
| webbrowser - a platform-independent API to launch a web browser. |
| |
| |
| Changed Modules |
| --------------- |
| |
| array -- new methods for array objects: count, extend, index, pop, and |
| remove |
| |
| binascii -- new functions b2a_hex and a2b_hex that convert between |
| binary data and its hex representation |
| |
| calendar -- Many new functions that support features including control |
| over which day of the week is the first day, returning strings instead |
| of printing them. Also new symbolic constants for days of week, |
| e.g. MONDAY, ..., SUNDAY. |
| |
| cgi -- FieldStorage objects have a getvalue method that works like a |
| dictionary's get method and returns the value attribute of the object. |
| |
| ConfigParser -- The parser object has new methods has_option, |
| remove_section, remove_option, set, and write. They allow the module |
| to be used for writing config files as well as reading them. |
| |
| ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now |
| optionally support the RFC 959 REST command. |
| |
| gzip -- readline and readlines now accept optional size arguments |
| |
| httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See |
| the module doc strings for details. |
| |
| locale -- implement getdefaultlocale for Win32 and Macintosh |
| |
| marshal -- no longer dumps core when marshaling deeply nested or |
| recursive data structures |
| |
| os -- new functions isatty, seteuid, setegid, setreuid, setregid |
| |
| os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3 |
| support under Unix. |
| |
| os/pty -- support for openpty and forkpty |
| |
| os.path -- fix semantics of os.path.commonprefix |
| |
| smtplib -- support for sending very long messages |
| |
| socket -- new function getfqdn() |
| |
| readline -- new functions to read, write and truncate history files. |
| The readline section of the library reference manual contains an |
| example. |
| |
| select -- add interface to poll system call |
| |
| shutil -- new copyfileobj function |
| |
| SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the |
| HTTP server. |
| |
| Tkinter -- optimization of function flatten |
| |
| urllib -- scans environment variables for proxy configuration, |
| e.g. http_proxy. |
| |
| whichdb -- recognizes dumbdbm format |
| |
| |
| Obsolete Modules |
| ---------------- |
| |
| None. However note that 1.6 made a whole slew of modules obsolete: |
| stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail, |
| poly, zmod, strop, util, whatsound. |
| |
| |
| Changed, New, Obsolete Tools |
| ---------------------------- |
| |
| None. |
| |
| |
| C-level Changes |
| --------------- |
| |
| Several cleanup jobs were carried out throughout the source code. |
| |
| All C code was converted to ANSI C; we got rid of all uses of the |
| Py_PROTO() macro, which makes the header files a lot more readable. |
| |
| Most of the portability hacks were moved to a new header file, |
| pyport.h; several other new header files were added and some old |
| header files were removed, in an attempt to create a more rational set |
| of header files. (Few of these ever need to be included explicitly; |
| they are all included by Python.h.) |
| |
| Trent Mick ensured portability to 64-bit platforms, under both Linux |
| and Win64, especially for the new Intel Itanium processor. Mick also |
| added large file support for Linux64 and Win64. |
| |
| The C APIs to return an object's size have been update to consistently |
| use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In |
| previous versions, the abstract interfaces used PyXXX_Length and the |
| concrete interfaces used PyXXX_Size. The old names, |
| e.g. PyObject_Length, are still available for backwards compatibility |
| at the API level, but are deprecated. |
| |
| The PyOS_CheckStack function has been implemented on Windows by |
| Fredrik Lundh. It prevents Python from failing with a stack overflow |
| on Windows. |
| |
| The GC changes resulted in creation of two new slots on object, |
| tp_traverse and tp_clear. The augmented assignment changes result in |
| the creation of a new slot for each in-place operator. |
| |
| The GC API creates new requirements for container types implemented in |
| C extension modules. See Include/objimpl.h for details. |
| |
| PyErr_Format has been updated to automatically calculate the size of |
| the buffer needed to hold the formatted result string. This change |
| prevents crashes caused by programmer error. |
| |
| New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable. |
| |
| PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions |
| that are the same as their non-Ex counterparts except they take an |
| extra flag argument that tells them to close the file when done. |
| |
| XXX There were other API changes that should be fleshed out here. |
| |
| |
| Windows Changes |
| --------------- |
| |
| New popen2/popen3/peopen4 in os module (see Changed Modules above). |
| |
| os.popen is much more usable on Windows 95 and 98. See Microsoft |
| Knowledge Base article Q150956. The Win9x workaround described there |
| is implemented by the new w9xpopen.exe helper in the root of your |
| Python installation. Note that Python uses this internally; it is not |
| a standalone program. |
| |
| Administrator privileges are no longer required to install Python |
| on Windows NT or Windows 2000. If you have administrator privileges, |
| Python's registry info will be written under HKEY_LOCAL_MACHINE. |
| Otherwise the installer backs off to writing Python's registry info |
| under HKEY_CURRENT_USER. The latter is sufficient for all "normal" |
| uses of Python, but will prevent some advanced uses from working |
| (for example, running a Python script as an NT service, or possibly |
| from CGI). |
| |
| [This was new in 1.6] The installer no longer runs a separate Tcl/Tk |
| installer; instead, it installs the needed Tcl/Tk files directly in the |
| Python directory. If you already have a Tcl/Tk installation, this |
| wastes some disk space (about 4 Megs) but avoids problems with |
| conflicting Tcl/Tk installations, and makes it much easier for Python |
| to ensure that Tcl/Tk can find all its files. |
| |
| [This was new in 1.6] The Windows installer now installs by default in |
| \Python20\ on the default volume, instead of \Program Files\Python-2.0\. |
| |
| |
| Updates to the changes between 1.5.2 and 1.6 |
| -------------------------------------------- |
| |
| The 1.6 NEWS file can't be changed after the release is done, so here |
| is some late-breaking news: |
| |
| New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(), |
| and changes to getlocale() and setlocale(). |
| |
| The new module is now enabled per default. |
| |
| It is not true that the encodings codecs cannot be used for normal |
| strings: the string.encode() (which is also present on 8-bit strings |
| !) allows using them for 8-bit strings too, e.g. to convert files from |
| cp1252 (Windows) to latin-1 or vice-versa. |
| |
| Japanese codecs are available from Tamito KAJIYAMA: |
| http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/ |
| |
| |
| ====================================================================== |