blob: 051643a9865c82fd216d5ba0de8828f77bc8f384 [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
7Core and builtins
8
Guido van Rossum9923ffe2002-06-04 19:52:53 +00009- Classes using __slots__ are now properly garbage collected.
10 [SF bug 519621]
11
12- Tightened the __slots__ rules: a slot name must be a valid Python
13 identifier.
14
Guido van Rossum2e4e0262002-06-04 05:58:34 +000015- The constructor for the module type now requires a name argument and
16 takes an optional docstring argument. Previously, this constructor
17 ignored its arguments. As a consequence, deriving a class from a
18 module (not from the module type) is now illegal; previously this
19 created an unnamed module, just like invoking the module type did.
20 [SF bug 563060]
21
Neal Norwitzd68f5172002-05-29 15:54:55 +000022- A new warning PendingDeprecationWarning was added to provide
23 direction on features which are in the process of being deprecated.
24 The warning will not be printed by default. To see the pending
25 deprecations, use -Walways::PendingDeprecationWarning::
26 as a command line option or warnings.filterwarnings() in code.
27
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000028- A new type object, 'basestring', is added. This is a common base type
Guido van Rossumcacfc072002-05-24 19:01:59 +000029 for 'str' and 'unicode', and can be used instead of
30 types.StringTypes, e.g. to test whether something is "a string":
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000031 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
Guido van Rossumcacfc072002-05-24 19:01:59 +000032 is an abstract base class and cannot be instantiated directly.
33
Fred Draked0ba6362002-05-02 21:28:26 +000034- Deprecated features of xrange objects have been removed as
35 promised. The start, stop, and step attributes and the tolist()
36 method no longer exist. xrange repetition and slicing have been
37 removed.
38
Guido van Rossum7dab2422002-04-26 19:40:56 +000039- New builtin function enumerate(x), from PEP 279. Example:
40 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
41 The argument can be an arbitrary iterable object.
42
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000043- The assert statement no longer tests __debug__ at runtime. This means
44 that assert statements cannot be disabled by assigning a false value
45 to __debug__.
46
Walter Dörwald068325e2002-04-15 13:36:47 +000047- A method zfill() was added to str and unicode, that fills a numeric
48 string to the left with zeros. For example,
49 "+123".zfill(6) -> "+00123".
50
Guido van Rossum862fe3c2002-04-15 12:36:47 +000051- Complex numbers supported divmod() and the // and % operators, but
52 these make no sense. Since this was documented, they're being
53 deprecated now.
54
Guido van Rossum26dd8302002-04-26 20:11:29 +000055- String and unicode methods lstrip(), rstrip() and strip() now take
56 an optional argument that specifies the characters to strip. For
57 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000058
Guido van Rossumc69343b2002-04-12 19:22:48 +000059- Added a new dict method pop(key). This removes and returns the
60 value corresponding to key. [SF patch #539949]
61
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000062- Changed new-style class instantiation so that when C's __new__
63 method returns something that's not a C instance, its __init__ is
64 not called. [SF bug #537450]
65
Guido van Rossum181e41a2002-04-06 00:23:25 +000066- Fixed super() to work correctly with class methods. [SF bug #535444]
67
Guido van Rossum47834462002-04-04 15:21:33 +000068- A new built-in type, bool, has been added, as well as built-in
69 names for its two values, True and False. Comparisons and sundry
70 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +000071 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +000072 is backward compatible.
73
Guido van Rossum95b62a62002-03-29 01:07:24 +000074- Fixed two bugs reported as SF #535905: under certain conditions,
75 deallocating a deeply nested structure could cause a segfault in the
76 garbage collector, due to interaction with the "trashcan" code;
77 access to the current frame during destruction of a local variable
78 could access a pointer to freed memory.
79
Neil Schemenauer9d50d132002-03-22 17:06:59 +000080- The optional object allocator has been enabled by default.
81
Guido van Rossum8c842552002-03-14 23:05:54 +000082- If you try to pickle an instance of a class that has __slots__ but
83 doesn't define or override __getstate__, a TypeError is now raised.
84 This is done by adding a bozo __getstate__ to the class that always
85 raises TypeError. (Before, this would appear to be pickled, but the
86 state of the slots would be lost.)
87
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000088- PyErr_Display will provide file and line information for all exceptions
89 that have an attribute print_file_and_line, not just SyntaxErrors.
90
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000091- The UTF-8 codec will now encode and decode Unicode surrogates
92 correctly and without raising exceptions for unpaired ones.
93
Neal Norwitz649b7592002-01-01 19:07:13 +000094- file.xreadlines() now raises a ValueError if the file is closed:
95 Previously, an xreadlines object was returned which would raise
96 a ValueError when the xreadlines.next() method was called.
97
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +000098- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +000099 An exception will now be raised if more than one argument is used.
100
Tim Petersaf8446f2001-12-21 21:36:50 +0000101Extension modules
102
Tim Peters81b92512002-04-29 01:37:32 +0000103- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000104 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000105 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000106
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000107- posix.killpg and posix.mknod have been added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000108
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000109- The locale module now exposes the C library's gettext interface.
110
Tim Petersfbf74f22002-03-14 19:06:01 +0000111- A security hole ("double free") was found in zlib-1.1.3, a popular
112 third party compression library used by some Python modules. The
113 hole was quickly plugged in zlib-1.1.4, and the Windows build of
114 Python now ships with zlib-1.1.4.
115
Martin v. Löwis688357e2002-04-08 21:28:20 +0000116- pwd, grp, and resource return enhanced tuples now, with symbolic
117 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000118
Martin v. Löwis99866332002-03-01 10:27:01 +0000119- array.array is now a type object. A new format character
120 'u' indicates Py_UNICODE arrays. For those, .tounicode and
121 .fromunicode methods are available. Arrays now support __iadd__
122 and __imul__.
123
Neal Norwitze790eae2002-01-01 21:14:12 +0000124- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000125 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
126 is called.
127
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000128- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
129 been added where available.
130
Tim Petersaf8446f2001-12-21 21:36:50 +0000131Library
132
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000133- Sockets now support timeout mode. After s.settimeout(T), where T is
134 a float expressing seconds, subsequent operations raise an exception
135 if they cannot be completed within T seconds. To disable timeout
136 mode, use s.settimeout(None).
137
138- getopt.gnu_getopt was added. This supports GNU-style option
139 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000140
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000141- Stop using strings for exceptions. String objects used for
142 exceptions are now classes deriving from Exception. The objects
143 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
144 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000145
Walter Dörwald474458d2002-06-04 15:16:29 +0000146- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
147 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
148 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
149 big endian systems were added to the codecs module. The old names
150 BOM32_* and BOM64_* were off by a factor of 2.
151
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000152- added degree/radian conversion functions to the math module.
153
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000154- ftplib.retrlines() now tests for callback is None rather than testing
155 for False. Was causing an error when given a callback object which
156 was callable but also returned len() as zero. The change may
157 create new breakage if the caller relied on the undocumented behavior
158 and called with callback set to [] or some other False value not
159 identical to None.
160
Tim Peters46c04e12002-05-05 20:40:00 +0000161- random.gauss() uses a piece of hidden state used by nothing else,
162 and the .seed() and .whseed() methods failed to reset it. In other
163 words, setting the seed didn't completely determine the sequence of
164 results produced by random.gauss(). It does now. Programs repeatedly
165 mixing calls to a seed method with calls to gauss() may see different
166 results now.
167
Fred Drake7f781c92002-05-01 20:33:53 +0000168- The pickle.Pickler class grew a clear_memo() method to mimic that
169 provided by cPickle.Pickler.
170
Tim Peters81b92512002-04-29 01:37:32 +0000171- difflib's SequenceMatcher class now does a dynamic analysis of
172 which elements are so frequent as to constitute noise. For
173 comparing files as sequences of lines, this generally works better
174 than the IS_LINE_JUNK function, and function ndiff's linejunk
175 argument defaults to None now as a result. A happy benefit is
176 that SequenceMatcher may run much faster now when applied
177 to large files with many duplicate lines (for example, C program
178 text with lots of repeated "}" and "return NULL;" lines).
179
Guido van Rossum256705b2002-04-23 13:29:43 +0000180- New Text.dump() method in Tkinter module.
181
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000182- New distutils commands for building packagers were added to
183 support pkgtool on Solaris and swinstall on HP-UX.
184
185- distutils now has a new abstract binary packager base class
186 command/bdist_packager, which simplifies writing packagers.
187 This will hopefully provide the missing bits to encourage
188 people to submit more packagers, e.g. for Debian, FreeBSD
189 and other systems.
190
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000191- The UTF-16, -LE and -BE now raise a NotImplementedError
192 for all calls to .readline(). Previously, they used to just
193 produce garbage or fail with an encoding error -- UTF-16 is
194 a 2-byte encoding and the C lib's line reading APIs don't
195 work well with these.
196
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000197- compileall now supports quiet operation.
198
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000199- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000200 connections.
201
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000202- socket module: the SSL support was broken out of the main
203 _socket module C helper and placed into a new _ssl helper
204 which now gets imported by socket.py if available and working.
205
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000206- encodings package: added aliases for all supported IANA character
207 sets
208
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000209- ftplib: to safeguard the user's privacy, anonymous login will use
210 "anonymous@" as default password, rather than the real user and host
211 name.
212
Fred Drake36736122002-01-10 13:50:31 +0000213- webbrowser: tightened up the command passed to os.system() so that
214 arbitrary shell code can't be executed because a bogus URL was
215 passed in.
216
Tim Peters11bd9942002-02-01 00:52:29 +0000217- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000218 gettext.find an optional all argument. Translations will now fallback
219 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000220
Martin v. Löwis9668b932002-01-12 11:27:42 +0000221- distutils bdist commands now offer a --skip-build option.
222
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000223- warnings.warn now accepts a Warning instance as first argument.
224
Fred Drakefed7e852002-04-04 19:36:15 +0000225- The xml.sax.expatreader.ExpatParser class will no longer create
226 circular references by using itself as the locator that gets passed
227 to the content handler implementation. [SF bug #535474]
228
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000229- The email.Parser.Parser class now properly parses strings regardless
230 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
231 or CRLF). Also, the Header class's constructor default arguments
232 has changed slightly so that an explicit maxlinelen value is always
233 honored.
234
Tim Petersaf8446f2001-12-21 21:36:50 +0000235Tools/Demos
236
Marc-André Lemburg46260092002-04-04 16:17:11 +0000237- freeze.py now produces binaries which can import shared modules,
238 unlike before when this failed due to missing symbol exports in
239 the generated binary.
240
Tim Petersaf8446f2001-12-21 21:36:50 +0000241Build
242
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000243- The configure option --without-doc-strings can be used to remove the
244 doc strings from the builtin functions and modules; this reduces the
245 size of the executable.
246
Tim Peters639295f2002-04-21 07:30:30 +0000247- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
248 say how or when to configure it, or how to turn it off.
249
Martin v. Löwis1142de32002-03-29 16:28:31 +0000250- On Unix, a shared libpython2.3.so can be created with --enable-shared.
251
Tim Peters8deda702002-03-30 10:06:07 +0000252- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
253 preprocessor symbols were eliminated. The internal decisions they
254 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000255
Fred Drake7d28b732002-05-02 21:17:00 +0000256- The tools used to build the documentation now work under Cygwin as
257 well as Unix.
258
Tim Petersaf8446f2001-12-21 21:36:50 +0000259C API
260
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000261- Added new macro PySequence_ITEM(o, i) that directly calls
262 sq_item without rechecking that o is a sequence and without
263 adjusting for negative indices.
264
Fred Draked0ba6362002-05-02 21:28:26 +0000265- PyRange_New() now raises ValueError if the fourth argument is not 1.
266 This is part of the removal of deprecated features of the xrange
267 object.
268
Guido van Rossum517c7d42002-04-26 02:49:14 +0000269- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
270 coercion if both arguments have the same type but this type has the
271 CHECKTYPES flag set. This is to better support proxies.
272
Neil Schemenauer9344b142002-04-12 23:00:08 +0000273- The type of tp_free has been changed from "void (*)(PyObject *)" to
274 "void (*)(void *)".
275
276- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
277
Guido van Rossum0986d822002-04-08 01:38:42 +0000278- A type can now inherit its metatype from its base type. Previously,
279 when PyType_Ready() was called, if ob_type was found to be NULL, it
280 was always set to &PyType_Type; now it is set to base->ob_type,
281 where base is tp_base, defaulting to &PyObject_Type.
282
283- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
284
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000285- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000286
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000287- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000288 without going through the buffer API.
289
Martin v. Löwis7198a522002-01-01 19:59:11 +0000290- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
291
Tim Peters10a3bb52001-12-25 19:07:38 +0000292- An old #define of ANY as void has been removed from pyport.h. This
293 hasn't been used since Python's pre-ANSI days, and the #define has
294 been marked as obsolete since then. SF bug 495548 says it created
295 conflicts with other packages, so keeping it around wasn't harmless.
296
Tim Petersaf8446f2001-12-21 21:36:50 +0000297- Because Python's magic number scheme broke on January 1st, we decided
298 to stop Python development. Thanks for all the fish!
299
Tim Petersfb05db22002-03-11 00:24:00 +0000300- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000301 scheme to a new one. See Python/import.c for details.
302
Tim Petersaf8446f2001-12-21 21:36:50 +0000303New platforms
304
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000305- GNU/Hurd is now supported.
306
Tim Petersaf8446f2001-12-21 21:36:50 +0000307Tests
308
309Windows
310
Tim Peters08e72952002-04-16 20:48:01 +0000311- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
312 of that has been fixed in the installer (disabled Wise's "delete in-
313 use files" uninstall option).
314
Guido van Rossum181e41a2002-04-06 00:23:25 +0000315- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
316
Tim Peters33187922002-04-04 20:02:04 +0000317- The installer now installs Start menu shortcuts under (the local
318 equivalent of) "All Users" when doing an Admin install.
319
Tim Petersfb05db22002-03-11 00:24:00 +0000320- file.truncate([newsize]) now works on Windows for all newsize values.
321 It used to fail if newsize didn't fit in 32 bits, reflecting a
322 limitation of MS _chsize (which is no longer used).
323
Tim Petersab034fa2002-02-01 11:27:43 +0000324- os.waitpid() is now implemented for Windows, and can be used to block
325 until a specified process exits. This is similar to, but not exactly
326 the same as, os.waitpid() on POSIX systems. If you're waiting for
327 a specific process whose pid was obtained from one of the spawn()
328 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000329 See the docs for details. The docs were changed to clarify that
330 spawn functions return, and waitpid requires, a process handle on
331 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000332
Tim Peters11bd9942002-02-01 00:52:29 +0000333- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000334 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000335 to a nasty problem: before 2.3, if you got a temp file on Windows, it
336 got wrapped in an object whose close() method first closed the
337 underlying file, then deleted the file. This usually worked fine.
338 However, the spawn family of functions on Windows create (at a low C
339 level) the same set of open files in the spawned process Q as were
340 open in the spawning process P. If a temp file f was among them, then
341 doing f.close() in P first closed P's C-level file handle on f, but Q's
342 C-level file handle on f remained open, so the attempt in P to delete f
343 blew up with a "Permission denied" error (Windows doesn't allow
344 deleting open files). This was surprising, subtle, and difficult to
345 work around.
346
347- The os module now exports all the symbolic constants usable with the
348 low-level os.open() on Windows: the new constants in 2.3 are
349 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
350 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
351 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
352 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
353 (so specify both if you want both; note that neither is useful unless
354 specified with O_CREAT too).
355
Tim Petersaf8446f2001-12-21 21:36:50 +0000356Mac
357
358
Tim Peters909c0912001-12-14 23:16:18 +0000359What's New in Python 2.2 final?
360Release date: 21-Dec-2001
361===============================
362
363Type/class unification and new-style classes
364
Barry Warsaw52acb492001-12-21 20:04:22 +0000365- pickle.py, cPickle: allow pickling instances of new-style classes
366 with a custom metaclass.
367
Tim Peters909c0912001-12-14 23:16:18 +0000368Core and builtins
369
Barry Warsaw52acb492001-12-21 20:04:22 +0000370- weakref proxy object: when comparing, unwrap both arguments if both
371 are proxies.
372
Tim Peters909c0912001-12-14 23:16:18 +0000373Extension modules
374
Barry Warsaw52acb492001-12-21 20:04:22 +0000375- binascii.b2a_base64(): fix a potential buffer overrun when encoding
376 very short strings.
377
378- cPickle: the obscure "fast" mode was suspected of causing stack
379 overflows on the Mac. Hopefully fixed this by setting the recursion
380 limit much smaller. If the limit is too low (it only affects
381 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
382 when compiling cPickle.c (or in pyconfig.h).
383
Tim Peters909c0912001-12-14 23:16:18 +0000384Library
385
Barry Warsaw52acb492001-12-21 20:04:22 +0000386- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
387 close or delete time).
388
389- rfc822.py: fixed a bug where the address '<>' was converted to None
390 instead of an empty string (also fixes the email.Utils module).
391
392- xmlrpclib.py: version 1.0.0; uses precision for doubles.
393
394- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000395 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000396
Tim Peters909c0912001-12-14 23:16:18 +0000397Tools/Demos
398
399Build
400
401C API
402
403New platforms
404
405Tests
406
407Windows
408
Barry Warsaw52acb492001-12-21 20:04:22 +0000409- distutils package: fixed broken Windows installers (bdist_wininst).
410
411- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
412 instances are deleted at process exit time.
413
414- socket.py: prevent mysterious warnings when socket instances are
415 deleted at process exit time.
416
417- posixmodule.c: fix a Windows crash with stat() of a filename ending
418 in backslash.
419
Tim Peters909c0912001-12-14 23:16:18 +0000420Mac
421
Barry Warsaw52acb492001-12-21 20:04:22 +0000422- The Carbon toolbox modules have been upgraded to Universal Headers
423 3.4, and experimental CoreGraphics and CarbonEvents modules have
424 been added. All only for framework-enabled MacOSX.
425
Tim Peters909c0912001-12-14 23:16:18 +0000426
Tim Peters6272dfd2001-12-13 19:34:00 +0000427What's New in Python 2.2c1?
428Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000429===========================
430
431Type/class unification and new-style classes
432
Barry Warsaw06557452001-12-14 20:47:12 +0000433- Guido's tutorial introduction to the new type/class features has
434 been extensively updated. See
435
436 http://www.python.org/2.2/descrintro.html
437
438 That remains the primary documentation in this area.
439
Guido van Rossum33bab012001-12-05 22:45:48 +0000440- Fixed a leak: instance variables declared with __slots__ were never
441 deleted!
442
Guido van Rossum4b800852001-12-03 00:54:52 +0000443- The "delete attribute" method of descriptor objects is called
444 __delete__, not __del__. In previous releases, it was mistakenly
445 called __del__, which created an unfortunate overloading condition
446 with finalizers. (The "get attribute" and "set attribute" methods
447 are still called __get__ and __set__, respectively.)
448
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000449- Some subtle issues with the super built-in were fixed:
450
451 (a) When super itself is subclassed, its __get__ method would still
452 return an instance of the base class (i.e., of super).
453
454 (b) super(C, C()).__class__ would return C rather than super. This
455 is confusing. To fix this, I decided to change the semantics of
456 super so that it only applies to code attributes, not to data
457 attributes. After all, overriding data attributes is not
458 supported anyway.
459
460 (c) The __get__ method didn't check whether the argument was an
461 instance of the type used in creation of the super instance.
462
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000463- Previously, hash() of an instance of a subclass of a mutable type
464 (list or dictionary) would return some value, rather than raising
465 TypeError. This has been fixed. Also, directly calling
466 dict.__hash__ and list.__hash__ now raises the same TypeError
467 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000468
Guido van Rossumd331cb52001-12-05 19:46:42 +0000469- New-style objects now support deleting their __dict__. This is for
470 all intents and purposes equivalent to assigning a brand new empty
471 dictionary, but saves space if the object is not used further.
472
Tim Petersb3c9af12001-11-17 00:21:57 +0000473Core and builtins
474
Tim Peters3caca232001-12-06 06:23:26 +0000475- -Qnew now works as documented in PEP 238: when -Qnew is passed on
476 the command line, all occurrences of "/" use true division instead
477 of classic division. See the PEP for details. Note that "all"
478 means all instances in library and 3rd-party modules, as well as in
479 your own code. As the PEP says, -Qnew is intended for use only in
480 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000481 Note that test_coercion.py in the standard Python test suite fails
482 under -Qnew; this is expected, and won't be repaired until true
483 division becomes the default (in the meantime, test_coercion is
484 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000485
Fred Drake6c01e252001-12-14 17:08:12 +0000486- complex() now only allows the first argument to be a string
487 argument, and raises TypeError if either the second arg is a string
488 or if the second arg is specified when the first is a string.
489
Tim Petersb3c9af12001-11-17 00:21:57 +0000490Extension modules
491
Martin v. Löwis560da622001-11-24 09:24:51 +0000492- gc.get_referents was renamed to gc.get_referrers.
493
Tim Petersb3c9af12001-11-17 00:21:57 +0000494Library
495
Tim Peters25059d32001-12-07 20:35:43 +0000496- Functions in the os.spawn() family now release the global interpreter
497 lock around calling the platform spawn. They should always have done
498 this, but did not before 2.2c1. Multithreaded programs calling
499 an os.spawn function with P_WAIT will no longer block all Python threads
500 until the spawned program completes. It's possible that some programs
501 relies on blocking, although more likely by accident than by design.
502
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000503- webbrowser defaults to netscape.exe on OS/2 now.
504
Martin v. Löwis652e1912001-11-25 14:50:56 +0000505- Tix.ResizeHandle exposes detach_widget, hide, and show.
506
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000507- The charset alias windows_1252 has been added.
508
Barry Warsaw06557452001-12-14 20:47:12 +0000509- types.StringTypes is a tuple containing the defined string types;
510 usually this will be (str, unicode), but if Python was compiled
511 without Unicode support it will be just (str,).
512
513- The pulldom and minidom modules were synchronized to PyXML.
514
Tim Petersb3c9af12001-11-17 00:21:57 +0000515Tools/Demos
516
Barry Warsaw06557452001-12-14 20:47:12 +0000517- A new script called Tools/scripts/google.py was added, which fires
518 off a search on Google.
519
Tim Petersb3c9af12001-11-17 00:21:57 +0000520Build
521
Barry Warsaw06557452001-12-14 20:47:12 +0000522- Note that release builds of Python should arrange to define the
523 preprocessor symbol NDEBUG on the command line (or equivalent).
524 In the 2.2 pre-release series we tried to define this by magic in
525 Python.h instead, but it proved to cause problems for extension
526 authors. The Unix, Windows and Mac builds now all define NDEBUG in
527 release builds via cmdline (or equivalent) instead. Ports to
528 other platforms should do likewise.
529
Jack Jansen1999ef42001-12-06 21:47:20 +0000530- It is no longer necessary to use --with-suffix when building on a
531 case-insensitive file system (such as Mac OS X HFS+). In the build
532 directory an extension is used, but not in the installed python.
533
Tim Petersb3c9af12001-11-17 00:21:57 +0000534C API
535
Tim Petersf582b822001-12-11 18:51:08 +0000536- New function PyDict_MergeFromSeq2() exposes the builtin dict
537 constructor's logic for updating a dictionary from an iterable object
538 producing key-value pairs.
539
Tim Peterscffed4b2001-11-29 03:26:37 +0000540- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000541 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000542 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
543 dump core in some bad cases. This has been repaired. As a result,
544 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
545 previously went unchallenged.
546
Tim Petersb3c9af12001-11-17 00:21:57 +0000547New platforms
548
549Tests
550
551Windows
552
553Mac
554
Jack Jansenffa260f2001-12-06 21:14:00 +0000555- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
556 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000557
Barry Warsaw06557452001-12-14 20:47:12 +0000558- Changed logic for finding python home in Mac OS X framework Pythons.
559 Now sys.executable points to the executable again, in stead of to
560 the shared library. The latter is used only for locating the python
561 home.
562
563
Tim Peters84362bc2001-10-19 17:55:30 +0000564What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000565Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000566===========================
567
568Type/class unification and new-style classes
569
Guido van Rossum3d27df02001-11-15 20:27:54 +0000570- Multiple inheritance mixing new-style and classic classes in the
571 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000572
573 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000574 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000575
576 The MRO (method resolution order) for each base class is respected
577 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000578 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000579 This needs to be documented.
580
Tim Petersa427a2b2001-10-29 22:25:45 +0000581- The new builtin dictionary() constructor, and dictionary type, have
582 been renamed to dict. This reflects a decade of common usage.
583
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000584- dict() now accepts an iterable object producing 2-sequences. For
585 example, dict(d.items()) == d for any dictionary d. The argument,
586 and the elements of the argument, can be any iterable objects.
587
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000588- New-style classes can now have a __del__ method, which is called
589 when the instance is deleted (just like for classic classes).
590
Guido van Rossum12d955c2001-10-26 14:56:06 +0000591- Assignment to object.__dict__ is now possible, for objects that are
592 instances of new-style classes that have a __dict__ (unless the base
593 class forbids it).
594
Guido van Rossumc8e56452001-10-22 00:43:43 +0000595- Methods of built-in types now properly check for keyword arguments
596 (formerly these were silently ignored). The only built-in methods
597 that take keyword arguments are __call__, __init__ and __new__.
598
Guido van Rossum86443212001-10-27 22:28:54 +0000599- The socket function has been converted to a type; see below.
600
Tim Peters84362bc2001-10-19 17:55:30 +0000601Core and builtins
602
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000603- Assignment to __debug__ raises SyntaxError at compile-time. This
604 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000605 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000606
Guido van Rossum12d955c2001-10-26 14:56:06 +0000607- Clarified the error messages for unsupported operands to an operator
608 (like 1 + '').
609
Tim Peters84362bc2001-10-19 17:55:30 +0000610Extension modules
611
Tim Peters5ebfd362001-11-13 23:11:19 +0000612- mmap has a new keyword argument, "access", allowing a uniform way for
613 both Windows and Unix users to create read-only, write-through and
614 copy-on-write memory mappings. This was previously possible only on
615 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000616 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000617 platforms. Thanks to Jay T Miller for repairing this!
618
Tim Peters169ded02001-11-03 19:57:21 +0000619- By default, the gc.garbage list now contains only those instances in
620 unreachable cycles that have __del__ methods; in 2.1 it contained all
621 instances in unreachable cycles. "Instances" here has been generalized
622 to include instances of both new-style and old-style classes.
623
Guido van Rossum12d955c2001-10-26 14:56:06 +0000624- The socket module defines a new method for socket objects,
625 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000626 send() until all data has been sent. Also, the socket function has
627 been converted to a subclassable type, like list and tuple (etc.)
628 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000629
630- Various bugfixes to the curses module. There is now a test suite
631 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000632
Guido van Rossum692adf12001-10-30 03:03:03 +0000633- binascii.b2a_base64 no longer places an arbitrary restriction of 57
634 bytes on its input.
635
Tim Peters84362bc2001-10-19 17:55:30 +0000636Library
637
Tim Peters5ebfd362001-11-13 23:11:19 +0000638- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000639 convenience function.
640
Tim Peters75335872001-11-03 19:35:43 +0000641- Symbolic group names in regular expressions must be unique. For
642 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
643 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000644 Python 2.2 detects this error at regexp compilation time;
645 previously, the error went undetected, and results were
646 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
647 pattern.subn() methods have been rewritten in C. Also, an
648 experimental function/method finditer() has been added, which works
649 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000650
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000651- Tix exposes more commands through the classes DirSelectBox,
652 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
653 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
654 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
655
Tim Peters98791af2001-10-23 01:59:54 +0000656- Traceback objects are now scanned by cyclic garbage collection, so
657 cycles created by casual use of sys.exc_info() no longer cause
658 permanent memory leaks (provided garbage collection is enabled).
659
Guido van Rossum49192142001-10-24 20:51:44 +0000660- os.extsep -- a new variable needed by the RISCOS support. It is the
661 separator used by extensions, and is '.' on all platforms except
662 RISCOS, where it is '/'. There is no need to use this variable
663 unless you have a masochistic desire to port your code to RISCOS.
664
Barry Warsaw012852b2001-11-16 16:17:27 +0000665- mimetypes.py has optional support for non-standard, but commonly
666 found types. guess_type() and guess_extension() now accept an
667 optional `strict' flag, defaulting to true, which controls whether
668 recognize non-standard types or not. A few non-standard types we
669 know about have been added. Also, when run as a script, there are
670 new -l and -e options.
671
672- statcache is now deprecated.
673
674- email.Utils.formatdate() now produces the preferred RFC 2822 style
675 dates with numeric timezones (it used to produce obsolete dates
676 hard coded to "GMT" timezone). An optional `localtime' flag is
677 added to produce dates in the local timezone, with daylight savings
678 time properly taken into account.
679
680- In pickle and cPickle, instead of masking errors in load() by
681 transforming them into SystemError, we let the original exception
682 propagate out. Also, implement support for __safe_for_unpickling__
683 in pickle, as it already was supported in cPickle.
684
Tim Peters84362bc2001-10-19 17:55:30 +0000685Tools/Demos
686
687Build
688
Barry Warsaw012852b2001-11-16 16:17:27 +0000689- The dbm module is built using libdb1 if available. The bsddb module
690 is built with libdb3 if available.
691
692- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
693
Tim Peters84362bc2001-10-19 17:55:30 +0000694C API
695
Tim Peters1fc240e2001-10-26 05:06:50 +0000696- New function PySequence_Fast_GET_SIZE() returns the size of a non-
697 NULL result from PySequence_Fast(), more quickly than calling
698 PySequence_Size().
699
Barry Warsaw012852b2001-11-16 16:17:27 +0000700- New argument unpacking function PyArg_UnpackTuple() added.
701
702- New functions PyObject_CallFunctionObjArgs() and
703 PyObject_CallMethodObjArgs() have been added to make it more
704 convenient and efficient to call functions and methods from C.
705
706- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
707 possible that this will propagate errors it didn't before.
708
709- New function PyObject_CheckReadBuffer(), which returns true if its
710 argument supports the single-segment readable buffer interface.
711
Tim Peters84362bc2001-10-19 17:55:30 +0000712New platforms
713
Guido van Rossum86443212001-10-27 22:28:54 +0000714- We've finally confirmed that this release builds on HP-UX 11.00,
715 *with* threads, and passes the test suite.
716
Tim Peters7a33d8b2001-11-05 02:51:07 +0000717- Thanks to a series of patches from Michael Muller, Python may build
718 again under OS/2 Visual Age C++.
719
Guido van Rossum49192142001-10-24 20:51:44 +0000720- Updated RISCOS port by Dietmar Schwertberger.
721
Tim Peters84362bc2001-10-19 17:55:30 +0000722Tests
723
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000724- Added a test script for the curses module. It isn't run automatically;
725 regrtest.py must be run with '-u curses' to enable it.
726
Tim Peters84362bc2001-10-19 17:55:30 +0000727Windows
728
Barry Warsaw012852b2001-11-16 16:17:27 +0000729Mac
730
731- PythonScript has been moved to unsupported and is slated to be
732 removed completely in the next release.
733
734- It should now be possible to build applets that work on both OS9 and
735 OSX.
736
737- The core is now linked with CoreServices not Carbon; as a side
738 result, default 8bit encoding on OSX is now ASCII.
739
740- Python should now build on OSX 10.1.1
741
Tim Peters84362bc2001-10-19 17:55:30 +0000742
Tim Petersabf925f2001-09-28 21:53:42 +0000743What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000744Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000745===========================
746
747Type/class unification and new-style classes
748
Guido van Rossum687ae002001-10-15 22:03:32 +0000749- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000750 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000751 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000752 remains: the __dict__ of a new-style class is a read-only proxy; you
753 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000754 __defined__ attribute of new-style types no longer exists, for lack
755 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000756 future a __cache__ may be resurrected with a similar function, if I
757 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000758
Tim Peters1c9ca872001-10-04 06:43:12 +0000759- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
760 always returned None, even when there was a class docstring).
761
762- doctest now finds and runs docstrings attached to new-style classes,
763 class methods, static methods, and properties.
764
Guido van Rossum9074ef62001-10-16 21:34:49 +0000765Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000766
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000767- A very subtle syntactical pitfall in list comprehensions was fixed.
768 For example: [a+b for a in 'abc', for b in 'def']. The comma in
769 this example is a mistake. Previously, this would silently let 'a'
770 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
771 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
772 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
773 Note that [a for a in <singleton>] is a convoluted way to say
774 [<singleton>] anyway, so it's not like any expressiveness is lost.
775
Guido van Rossum9074ef62001-10-16 21:34:49 +0000776- getattr(obj, name, default) now only catches AttributeError, as
777 documented, rather than returning the default value for all
778 exceptions (which could mask bugs in a __getattr__ hook, for
779 example).
780
Fred Drakecb7a6b52001-10-22 18:41:51 +0000781- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000782 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000783 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000784 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000785
Guido van Rossum1c486092001-10-19 02:05:35 +0000786- unicode(obj) now behaves more like str(obj), accepting arbitrary
787 objects, and calling a __unicode__ method if it exists.
788 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000789 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000790
Barry Warsawf6fb1712001-10-19 05:35:40 +0000791- isinstance() now allows any object as the first argument and a
792 class, a type or something with a __bases__ tuple attribute for the
793 second argument. The second argument may also be a tuple of a
794 class, type, or something with __bases__, in which case isinstance()
795 will return true if the first argument is an instance of any of the
796 things contained in the second argument tuple. E.g.
797
798 isinstance(x, (A, B))
799
800 returns true if x is an instance of A or B.
801
Guido van Rossum9074ef62001-10-16 21:34:49 +0000802Extension modules
803
804- thread.start_new_thread() now returns the thread ID (previously None).
805
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000806- binascii has now two quopri support functions, a2b_qp and b2a_qp.
807
Guido van Rossumc524d952001-10-19 01:31:59 +0000808- readline now supports setting the startup_hook and the
809 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000810
Guido van Rossumc524d952001-10-19 01:31:59 +0000811- os and posix supports chroot(), setgroups() and unsetenv() where
812 available. The stat(), fstat(), statvfs() and fstatvfs() functions
813 now return "pseudo-sequences" -- the various fields can now be
814 accessed as attributes (e.g. os.stat("/").st_mtime) but for
815 backwards compatibility they also behave as a fixed-length sequence.
816 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000817 attributes.
818
819- time: localtime(), gmtime() and strptime() now return a
820 pseudo-sequence similar to the os.stat() return value, with
821 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000822
Guido van Rossum9074ef62001-10-16 21:34:49 +0000823- Decompression objects in the zlib module now accept an optional
824 second parameter to decompress() that specifies the maximum amount
825 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000826
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000827- optional SSL support in the socket module now exports OpenSSL
828 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
829 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000830 automatically seed its PRNG. Also, the keyfile and certfile
831 arguments to socket.ssl() are now optional.
832
833- posixmodule (and by extension, the os module on POSIX platforms) now
834 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000835
Guido van Rossum9074ef62001-10-16 21:34:49 +0000836Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000837
Tim Peters7402f792001-10-02 03:53:41 +0000838- doctest now excludes functions and classes not defined by the module
839 being tested, thanks to Tim Hochberg.
840
Fred Drakecb7a6b52001-10-22 18:41:51 +0000841- HotShot, a new profiler implemented using a C-based callback, has
842 been added. This substantially reduces the overhead of profiling,
843 but it is still quite preliminary. Support modules and
844 documentation will be added in upcoming releases (before 2.2 final).
845
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000846- profile now produces correct output in situations where an exception
847 raised in Python is cleared by C code (e.g. hasattr()). This used
848 to cause wrong output, including spurious claims of recursive
849 functions and attribution of time spent to the wrong function.
850
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000851 The code and documentation for the derived OldProfile and HotProfile
852 profiling classes was removed. The code hasn't worked for years (if
853 you tried to use them, they raised exceptions). OldProfile
854 intended to reproduce the behavior of the profiler Python used more
855 than 7 years ago, and isn't interesting anymore. HotProfile intended
856 to provide a faster profiler (but producing less information), and
857 that's a worthy goal we intend to meet via a different approach (but
858 without losing information).
859
Tim Peterscce092d2001-10-09 05:31:56 +0000860- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000861 a much better system-specific calibration constant. The constant can
862 now be specified in an instance constructor, or as a Profile class or
863 instance variable, instead of by editing profile.py's source code.
864 Calibration must still be done manually (see the docs for the profile
865 module).
866
867 Note that Profile.calibrate() must be overriden by subclasses.
868 Improving the accuracy required exploiting detailed knowledge of
869 profiler internals; the earlier method abstracted away the details
870 and measured a simplified model instead, but consequently computed
871 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000872
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000873- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000874 which indicates whether output is intended for the header 'Q'
875 encoding.
876
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000877- The SocketServer.ThreadingMixIn class now closes the request after
878 finish_request() returns. (Not when it errors out though.)
879
Barry Warsawf6fb1712001-10-19 05:35:40 +0000880- The nntplib module's NNTP.body() method has grown a `file' argument
881 to allow saving the message body to a file.
882
883- The email package has added a class email.Parser.HeaderParser which
884 only parses headers and does not recurse into the message's body.
885 Also, the module/class MIMEAudio has been added for representing
886 audio data (contributed by Anthony Baxter).
887
888- ftplib should be able to handle files > 2GB.
889
890- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
891 ON, and OFF.
892
Fred Drakecb7a6b52001-10-22 18:41:51 +0000893- xml.dom.minidom NodeList objects now support the length attribute
894 and item() method as required by the DOM specifications.
895
Guido van Rossumed554f62001-10-02 23:15:37 +0000896Tools/Demos
897
898- Demo/dns was removed. It no longer serves any purpose; a package
899 derived from it is now maintained by Anthony Baxter, see
900 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000901
Barry Warsawf6fb1712001-10-19 05:35:40 +0000902- The freeze tool has been made more robust, and two new options have
903 been added: -X and -E.
904
Tim Petersabf925f2001-09-28 21:53:42 +0000905Build
906
Barry Warsawf6fb1712001-10-19 05:35:40 +0000907- configure will use CXX in LINKCC if CXX is used to build main() and
908 the system requires to link a C++ main using the C++ compiler.
909
Tim Petersabf925f2001-09-28 21:53:42 +0000910C API
911
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000912- The documentation for the tp_compare slot is updated to require that
913 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
914 not correct. This is not yet enforced but will be enforced in
915 Python 2.3; even later, we may use -2 to indicate errors and +2 for
916 "NotImplemented". Right now, -1 should be used for an error return.
917
Tim Petersd38b1c72001-09-30 05:09:37 +0000918- PyLong_AsLongLong() now accepts int (as well as long) arguments.
919 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
920 as long) arguments.
921
Guido van Rossum3c288632001-10-16 21:13:49 +0000922- PyThread_start_new_thread() now returns a long int giving the thread
923 ID, if one can be calculated; it returns -1 for error, 0 if no
924 thread ID is calculated (this is an incompatible change, but only
925 the thread module used this API). This code has only really been
926 tested on Linux and Windows; other platforms please beware (and
927 report any bugs or strange behavior).
928
Guido van Rossum1c486092001-10-19 02:05:35 +0000929- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
930 input.
931
Tim Petersabf925f2001-09-28 21:53:42 +0000932New platforms
933
934Tests
935
936Windows
937
Tim Peters04cf1d32001-10-09 22:39:40 +0000938- Installer: If you install IDLE, and don't disable file-extension
939 registration, a new "Edit with IDLE" context (right-click) menu entry
940 is created for .py and .pyw files.
941
Tim Peters1ce3cf72001-10-01 17:58:40 +0000942- The signal module now supports SIGBREAK on Windows, thanks to Steven
943 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
944 action remains to call Win32 ExitProcess(). This can be changed via
945 signal.signal(). For example:
946
947 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
948 # (SIGINT) behavior.
949 import signal
950 signal.signal(signal.SIGBREAK,
951 signal.default_int_handler)
952
953 try:
954 while 1:
955 pass
956 except KeyboardInterrupt:
957 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
958 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
959 # program without the possibility for any Python-level cleanup).
960 print "Clean exit"
961
Tim Petersabf925f2001-09-28 21:53:42 +0000962
Tim Petersb07352e2001-09-08 01:25:47 +0000963What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000964Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000965===========================
966
Guido van Rossum808eea72001-09-25 04:15:41 +0000967Type/class unification and new-style classes
968
969- pydoc and inspect are now aware of new-style classes;
970 e.g. help(list) at the interactive prompt now shows proper
971 documentation for all operations on list objects.
972
973- Applications using Jim Fulton's ExtensionClass module can now safely
974 be used with Python 2.2. In particular, Zope 2.4.1 now works with
975 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
976 examples also work again. It is hoped that Gtk and Boost also work
977 with 2.2a4 and beyond. (If you can confirm this, please write
978 webmaster@python.org; if there are still problems, please open a bug
979 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000980
Tim Peters66c1a522001-09-24 21:17:50 +0000981- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000982 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +0000983 in the constructed property object. fget, fset and fdel weren't
984 discoverable from Python in 2.2a3. __doc__ is new, and allows to
985 associate a docstring with a property.
986
Guido van Rossum808eea72001-09-25 04:15:41 +0000987- Comparison overloading is now more completely implemented. For
988 example, a str subclass instance can properly be compared to a str
989 instance, and it can properly overload comparison. Ditto for most
990 other built-in object types.
991
992- The repr() of new-style classes has changed; instead of <type
993 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
994 *except* for built-in types, which are still rendered as <type
995 'Foo'> (to avoid upsetting existing code that might parse or
996 otherwise rely on repr() of certain type objects).
997
998- The repr() of new-style objects is now always <Foo object at XXX>;
999 previously, it was sometimes <Foo instance at XXX>.
1000
1001- For new-style classes, what was previously called __getattr__ is now
1002 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001003 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001004 one in classic classes is defined which is called only if regular
1005 attribute access raises AttributeError; to catch *all* attribute
1006 access, you can use __getattribute__ (for new-style classes). If
1007 both are defined, __getattribute__ is called first, and if it raises
1008 AttributeError, __getattr__ is called.
1009
1010- The __class__ attribute of new-style objects can be assigned to.
1011 The new class must have the same C-level object layout as the old
1012 class.
1013
1014- The builtin file type can be subclassed now. In the usual pattern,
1015 "file" is the name of the builtin type, and file() is a new builtin
1016 constructor, with the same signature as the builtin open() function.
1017 file() is now the preferred way to open a file.
1018
1019- Previously, __new__ would only see sequential arguments passed to
1020 the type in a constructor call; __init__ would see both sequential
1021 and keyword arguments. This made no sense whatsoever any more, so
1022 now both __new__ and __init__ see all arguments.
1023
1024- Previously, hash() applied to an instance of a subclass of str or
1025 unicode always returned 0. This has been repaired.
1026
1027- Previously, an operation on an instance of a subclass of an
1028 immutable type (int, long, float, complex, tuple, str, unicode),
1029 where the subtype didn't override the operation (and so the
1030 operation was handled by the builtin type), could return that
1031 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001032 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001033 with the same value as s.
1034
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001035- Provisional support for pickling new-style objects has been added.
1036
Guido van Rossum808eea72001-09-25 04:15:41 +00001037Core
1038
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001039- file.writelines() now accepts any iterable object producing strings.
1040
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001041- PyUnicode_FromEncodedObject() now works very much like
1042 PyObject_Str(obj) in that it tries to use __str__/tp_str
1043 on the object if the object is not a string or buffer. This
1044 makes unicode() behave like str() when applied to non-string/buffer
1045 objects.
1046
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001047- PyFile_WriteObject now passes Unicode objects to the file's write
1048 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001049 of a print statement must support Unicode objects, i.e. they must
1050 at least convert them into ASCII strings.
1051
Guido van Rossum624c8af2001-09-18 15:21:04 +00001052- Thread scheduling on Solaris should be improved; it is no longer
1053 necessary to insert a small sleep at the start of a thread in order
1054 to let other runnable threads be scheduled.
1055
Tim Petersb07352e2001-09-08 01:25:47 +00001056Library
1057
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001058- StringIO.StringIO instances and cStringIO.StringIO instances support
1059 read character buffer compatible objects for their .write() methods.
1060 These objects are converted to strings and then handled as such
1061 by the instances.
1062
Barry Warsaw2f600732001-09-24 04:28:10 +00001063- The "email" package has been added. This is basically a port of the
1064 mimelib package <http://sf.net/projects/mimelib> with API changes
1065 and some implementations updated to use iterators and generators.
1066
Tim Peters8a9c2842001-09-22 21:30:22 +00001067- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1068 restores the ability of Tools/scripts/ndiff.py to start producing output
1069 before the entire comparison is complete.
1070
Barry Warsaw58b072d2001-09-22 04:44:21 +00001071- StringIO.StringIO instances and cStringIO.StringIO instances support
1072 iteration just like file objects (i.e. their .readline() method is
1073 called for each iteration until it returns an empty string).
1074
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001075- The codecs module has grown four new helper APIs to access
1076 builtin codecs: getencoder(), getdecoder(), getreader(),
1077 getwriter().
1078
Guido van Rossum624c8af2001-09-18 15:21:04 +00001079- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1080 simplifies writing XML RPC servers.
1081
Barry Warsaw647d5e82001-09-28 17:01:02 +00001082- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001083 after interpretation of symbolic links. On non-Unix systems, this
1084 is an alias for os.path.abspath().
1085
Tim Peters16a77ad2001-09-08 04:00:12 +00001086- operator.indexOf() (PySequence_Index() in the C API) now works with any
1087 iterable object.
1088
Guido van Rossum624c8af2001-09-18 15:21:04 +00001089- smtplib now supports various authentication and security features of
1090 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001091
Guido van Rossum624c8af2001-09-18 15:21:04 +00001092- hmac: a new module implementing keyed hashing for message
1093 authentication.
1094
1095- mimetypes now recognizes more extensions and file types. At the
1096 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001097
Guido van Rossum624c8af2001-09-18 15:21:04 +00001098- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001099 Python 2.2 bytecode generation. It has also been promoted from a
1100 Tool to a standard library package. (Tools/compiler still exists as
1101 a sample driver.)
1102
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001103Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001104
Tim Petersb07352e2001-09-08 01:25:47 +00001105Build
1106
Guido van Rossum624c8af2001-09-18 15:21:04 +00001107- Large file support (LFS) is now automatic when the platform supports
1108 it; no more manual configuration tweaks are needed. On Linux, at
1109 least, it's possible to have a system whose C library supports large
1110 files but whose kernel doesn't; in this case, large file support is
1111 still enabled but doesn't do you any good unless you upgrade your
1112 kernel or share your Python executable with another system whose
1113 kernel has large file support.
1114
1115- The configure script now supplies plausible defaults in a
1116 cross-compilation environment. This doesn't mean that the supplied
1117 values are always correct, or that cross-compilation now works
1118 flawlessly -- but it's a first step (and it shuts up most of
1119 autoconf's warnings about AC_TRY_RUN).
1120
1121- The Unix build is now a bit less chatty, courtesy of the parser
1122 generator. The build is completely silent (except for errors) when
1123 using "make -s", thanks to a -q option to setup.py.
1124
Tim Petersb07352e2001-09-08 01:25:47 +00001125C API
1126
Guido van Rossum624c8af2001-09-18 15:21:04 +00001127- The "structmember" API now supports some new flag bits to deny read
1128 and/or write access to attributes in restricted execution mode.
1129
Tim Petersb07352e2001-09-08 01:25:47 +00001130New platforms
1131
Guido van Rossum624c8af2001-09-18 15:21:04 +00001132- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1133 (http://familiar.handhelds.org).
1134
Tim Petersb07352e2001-09-08 01:25:47 +00001135Tests
1136
Tim Peters8a9c2842001-09-22 21:30:22 +00001137- The "classic" standard tests, which work by comparing stdout to
1138 an expected-output file under Lib/test/output/, no longer stop at
1139 the first mismatch. Instead the test is run to completion, and a
1140 variant of ndiff-style comparison is used to report all differences.
1141 This is much easier to understand than the previous style of reporting.
1142
1143- The unittest-based standard tests now use regrtest's test_main()
1144 convention, instead of running as a side-effect of merely being
1145 imported. This allows these tests to be run in more natural and
1146 flexible ways as unittests, outside the regrtest framework.
1147
1148- regrtest.py is much better integrated with unittest and doctest now,
1149 especially in regard to reporting errors.
1150
Tim Petersb07352e2001-09-08 01:25:47 +00001151Windows
1152
Guido van Rossum624c8af2001-09-18 15:21:04 +00001153- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001154 that support it (NTFS under Windows 2000). See "What's New in
1155 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001156
Tim Petersb07352e2001-09-08 01:25:47 +00001157
Tim Petersedc99312001-08-22 21:36:50 +00001158What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001159Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001160===========================
1161
1162Core
1163
Tim Peters9fffa3e2001-09-04 05:14:19 +00001164- Conversion of long to float now raises OverflowError if the long is too
1165 big to represent as a C double.
1166
Tim Peters32f453e2001-09-03 08:35:41 +00001167- The 3-argument builtin pow() no longer allows a third non-None argument
1168 if either of the first two arguments is a float, or if both are of
1169 integer types and the second argument is negative (in which latter case
1170 the arguments are converted to float, so this is really the same
1171 restriction).
1172
Tim Peters5d2b77c2001-09-03 05:47:38 +00001173- The builtin dir() now returns more information, and sometimes much
1174 more, generally naming all attributes of an object, and all attributes
1175 reachable from the object via its class, and from its class's base
1176 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1177 an empty list. In 2.2a3,
1178
1179 >>> dir([])
1180 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1181 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1182 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1183 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1184 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1185 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1186 'reverse', 'sort']
1187
1188 dir(module) continues to return only the module's attributes, though.
1189
Tim Petersbdee63f2001-09-02 03:40:59 +00001190- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001191 than raising OverflowError. This is a partial implementation of PEP
1192 237. You can use -Wdefault::OverflowWarning to enable a warning for
1193 this situation, and -Werror::OverflowWarning to revert to the old
1194 OverflowError exception.
1195
Guido van Rossum61c345f2001-09-04 03:26:15 +00001196- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001197 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001198 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1199 -Qold, meaning the / operator has its classic meaning and no
1200 warnings are issued. Using -Qwarn issues a run-time warning about
1201 all uses of classic division for int and long arguments; -Qwarnall
1202 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001203 (for use with fixdiv.py).
1204 [Note: the remainder of this paragraph (preserved below) became
1205 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1206 <obsolete>
1207 Using -Qnew is questionable; it turns on new division by default, but
1208 only in the __main__ module. You can usefully combine -Qwarn or
1209 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1210 warns about classic division everywhere else.
1211 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001212
Tim Petersbdee63f2001-09-02 03:40:59 +00001213- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001214 long, float, str, unicode, and tuple. (The types complex, list and
1215 dictionary can also be subclassed; this was introduced earlier.)
1216 Note that restrictions apply when subclassing immutable built-in
1217 types: you can only affect the value of the instance by overloading
1218 __new__. You can add mutable attributes, and the subclass instances
1219 will have a __dict__ attribute, but you cannot change the "value"
1220 (as implemented by the base class) of an immutable subclass instance
1221 once it is created.
1222
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001223- The dictionary constructor now takes an optional argument, a
1224 mapping-like object, and initializes the dictionary from its
1225 (key, value) pairs.
1226
Tim Petersbdee63f2001-09-02 03:40:59 +00001227- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001228 "cooperative super calls" in a multiple inheritance setting. For an
1229 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1230
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001231- A new built-in type, property, has been added. This enables the
1232 creation of "properties". These are attributes implemented by
1233 getter and setter functions (or only one of these for read-only or
1234 write-only attributes), without the need to override __getattr__.
1235 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001236
Tim Petersbdee63f2001-09-02 03:40:59 +00001237- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001238 liberalized, to allow leading zeroes. Examples of literals now
1239 legal that were SyntaxErrors before:
1240
1241 00.0 0e3 0100j 07.5 00000000000000000008.
1242
Tim Petersbdee63f2001-09-02 03:40:59 +00001243- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001244 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1245
Tim Petersedc99312001-08-22 21:36:50 +00001246Library
1247
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001248- telnetlib includes symbolic names for the options, and support for
1249 setting an option negotiation callback.
1250
Tim Petersa40c7932001-09-05 22:36:56 +00001251- The new C standard no longer requires that math libraries set errno to
1252 ERANGE on overflow. For platform libraries that exploit this new
1253 freedom, Python's overflow-checking was wholly broken. A new overflow-
1254 checking scheme attempts to repair that, but may not be reliable on all
1255 platforms (C doesn't seem to provide anything both useful and portable
1256 in this area anymore).
1257
Martin v. Löwis44f86962001-09-05 13:44:54 +00001258- Asynchronous timeout actions are available through the new class
1259 threading.Timer.
1260
Tim Peters78526162001-09-05 00:53:45 +00001261- math.log and math.log10 now return sensible results for even huge
1262 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1263
Tim Petersbdee63f2001-09-02 03:40:59 +00001264- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001265 currently held. See the docs for the imp module.
1266
Tim Petersbdee63f2001-09-02 03:40:59 +00001267- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001268 dumps containing ints written on platforms where Python ints are 8 bytes.
1269 When read on a box where Python ints are 4 bytes, such values are
1270 converted to Python longs.
1271
Tim Petersbdee63f2001-09-02 03:40:59 +00001272- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001273 code objects is no longer allowed. This plugs a security hole.
1274
Steve Purcell6091cd62001-09-06 16:05:17 +00001275- unittest.TestResult instances no longer store references to tracebacks
1276 generated by test failures. This prevents unexpected dangling references
1277 to objects that should be garbage collected between tests.
1278
Tim Petersedc99312001-08-22 21:36:50 +00001279Tools
1280
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001281- Tools/scripts/fixdiv.py has been added which can be used to fix
1282 division operators as per PEP 238.
1283
Tim Petersedc99312001-08-22 21:36:50 +00001284Build
1285
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001286- If you are an adventurous person using Mac OS X you may want to look at
1287 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1288 application, which can be used for experimenting with Carbon or Cocoa.
1289 Discussion of this on pythonmac-sig, please.
1290
Tim Peters7eea37e2001-09-04 22:08:56 +00001291C API
1292
1293- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001294
Tim Peters9fffa3e2001-09-04 05:14:19 +00001295- Note that PyLong_AsDouble can fail! This has always been true, but no
1296 callers checked for it. It's more likely to fail now, because overflow
1297 errors are properly detected now. The proper way to check:
1298
1299 double x = PyLong_AsDouble(some_long_object);
1300 if (x == -1.0 && PyErr_Occurred()) {
1301 /* The conversion failed. */
1302 }
1303
Tim Petersbdee63f2001-09-02 03:40:59 +00001304- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001305 compile but will not participate in GC. To upgrade an extension
1306 module:
1307
1308 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001309
Neil Schemenauer4042c692001-08-30 15:38:01 +00001310 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1311 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001312
Neil Schemenauer4042c692001-08-30 15:38:01 +00001313 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1314 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001315
Neil Schemenauer4042c692001-08-30 15:38:01 +00001316 - remove PyGC_HEAD_SIZE from object size calculations
1317
1318 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1319
Tim Petersbdee63f2001-09-02 03:40:59 +00001320- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001321 These can be used safely to construct string objects from a
1322 sprintf-style format string (similar to the format string supported
1323 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001324
Tim Petersedc99312001-08-22 21:36:50 +00001325New platforms
1326
Tim Petersb7da0902001-09-02 23:01:43 +00001327- Stephen Hansen contributed patches sufficient to get a clean compile
1328 under Borland C (Windows), but he reports problems running it and ran
1329 out of time to complete the port. Volunteers? Expect a MemoryError
1330 when importing the types module; this is probably shallow, and
1331 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001332
Tim Petersedc99312001-08-22 21:36:50 +00001333Tests
1334
1335Windows
1336
Tim Peters6e13a562001-09-06 00:32:15 +00001337- Large file support is now enabled on Win32 platforms as well as on
1338 Win64. This means that, for example, you can use f.tell() and f.seek()
1339 to manipulate files larger than 2 gigabytes (provided you have enough
1340 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001341 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1342 filesize limit, and large file support makes no difference there.
1343 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1344 NTFS has no practical limit on file size, and files of any size can be
1345 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001346
Tim Petersbdee63f2001-09-02 03:40:59 +00001347- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001348 points to command.com (patch from Brian Quinlan).
1349
Tim Petersedc99312001-08-22 21:36:50 +00001350
Tim Peters20f51a72001-07-21 02:31:40 +00001351What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001352Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001353===========================
1354
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001355Build
1356
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001357- Tim Peters developed a brand new Windows installer using Wise 8.1,
1358 generously donated to us by Wise Solutions.
1359
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001360- configure supports a new option --enable-unicode, with the values
1361 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1362 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001363
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001364- A new configure option --enable-framework builds a Mac OS X framework,
1365 which "make frameworkinstall" will install. This provides a starting
1366 point for more mac-like functionality, join pythonmac-sig@python.org
1367 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001368
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001369- The NeXT platform is no longer supported.
1370
1371- The `new' module is now statically linked.
1372
Tim Peters0afb6092001-08-15 06:06:44 +00001373Tools
1374
1375- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001376 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001377 the module docstring for details.
1378
Tim Peters20f51a72001-07-21 02:31:40 +00001379Tests
1380
Tim Peters5e824c32001-08-12 22:25:01 +00001381- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001382 platforms, allowing to give clearer test result output. regrtest
1383 also has optional --use/-u switch to run normally disabled tests
1384 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001385
Tim Peters20f51a72001-07-21 02:31:40 +00001386- Several new tests in the standard test suite, with special thanks to
1387 Nick Mathewson.
1388
1389Core
1390
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001391- The floor division operator // has been added as outlined in PEP
1392 238. The / operator still provides classic division (and will until
1393 Python 3.0) unless "from __future__ import division" is included, in
1394 which case the / operator will provide true division. The operator
1395 module provides truediv() and floordiv() functions. Augmented
1396 assignment variants are included, as are the equivalent overloadable
1397 methods and C API methods. See the PEP for a full discussion:
1398 <http://python.sf.net/peps/pep-0238.html>
1399
Tim Peters6cd6a822001-08-17 22:11:27 +00001400- Future statements are now effective in simulated interactive shells
1401 (like IDLE). This should "just work" by magic, but read Michael
1402 Hudson's "Future statements in simulated shells" PEP 264 for full
1403 details: <http://python.sf.net/peps/pep-0264.html>.
1404
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001405- The type/class unification (PEP 252-253) was integrated into the
1406 trunk and is not so tentative any more (the exact specification of
1407 some features is still tentative). A lot of work has done on fixing
1408 bugs and adding robustness and features (performance still has to
1409 come a long way).
1410
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001411- Warnings about a mismatch in the Python API during extension import
1412 now use the Python warning framework (which makes it possible to
1413 write filters for these warnings).
1414
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001415- A function's __dict__ (aka func_dict) will now always be a
1416 dictionary. It used to be possible to delete it or set it to None,
1417 but now both actions raise TypeErrors. It is still legal to set it
1418 to a dictionary object. Getting func.__dict__ before any attributes
1419 have been assigned now returns an empty dictionary instead of None.
1420
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001421- A new command line option, -E, was added which disables the use of
1422 all environment variables, or at least those that are specifically
1423 significant to Python. Usually those have a name starting with
1424 "PYTHON". This was used to fix a problem where the tests fail if
1425 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1426 older distribution.
1427
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001428Library
1429
Tim Peters5e824c32001-08-12 22:25:01 +00001430- New class Differ and new functions ndiff() and restore() in difflib.py.
1431 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001432 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001433
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001434- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1435 value using the minimal quoting required for the value; more
1436 reliable than using xml.sax.saxutils.escape() for attribute values.
1437
1438- Readline completion support for cmd.Cmd was added.
1439
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001440- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1441
1442- Added function threading.BoundedSemaphore()
1443
1444- Added Ka-Ping Yee's cgitb.py module.
1445
1446- The `new' module now exposes the CO_xxx flags.
1447
Martin v. Löwis560da622001-11-24 09:24:51 +00001448- The gc module offers the get_referents function.
1449
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001450New platforms
1451
1452C API
1453
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001454- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1455 which provide a cross-platform implementations for the
1456 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1457 the standard sprintf() and vsprintf() C lib APIs, these versions
1458 apply bounds checking on the used buffer which enhances protection
1459 against buffer overruns.
1460
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001461- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001462 and extensions using different Unicode widths is rendered next to
1463 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001464 will result in an ImportError. Unicode extensions writers must make
1465 sure to check the Unicode width compatibility in their extensions by
1466 using at least one of the mangled Unicode APIs in the extension.
1467
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001468- Two new flags METH_NOARGS and METH_O are available in method definition
1469 tables to simplify implementation of methods with no arguments and a
1470 single untyped argument. Calling such methods is more efficient than
1471 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1472 deprecated.
1473
Tim Petersc1731372001-08-04 08:12:36 +00001474Windows
1475
1476- "import module" now compiles module.pyw if it exists and nothing else
1477 relevant is found.
1478
Tim Peters20f51a72001-07-21 02:31:40 +00001479
Guido van Rossum55a78992001-07-17 17:22:32 +00001480What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001481Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001482===========================
1483
1484Core
Tim Petersa814db52001-05-14 07:05:58 +00001485
Tim Peters6d6c1a32001-08-02 04:15:00 +00001486- TENTATIVELY, a large amount of code implementing much of what's
1487 described in PEP 252 (Making Types Look More Like Classes) and PEP
1488 253 (Subtyping Built-in Types) was added. This will be released
1489 with Python 2.2a1. Documentation will be provided separately
1490 through http://www.python.org/2.2/. The purpose of releasing this
1491 with Python 2.2a1 is to test backwards compatibility. It is
1492 possible, though not likely, that a decision is made not to release
1493 this code as part of 2.2 final, if any serious backwards
1494 incompapatibilities are found during alpha testing that cannot be
1495 repaired.
1496
Guido van Rossum55a78992001-07-17 17:22:32 +00001497- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001498 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001499 more 'yield' statements. See PEP 255. Since this adds a new
1500 keyword to the language, this feature must be enabled by including a
1501 future statement: "from __future__ import generators" (see PEP 236).
1502 Generators will become a standard feature in a future release
1503 (probably 2.3). Without this future statement, 'yield' remains an
1504 ordinary identifier, but a warning is issued each time it is used.
1505 (These warnings currently don't conform to the warnings framework of
1506 PEP 230; we intend to fix this in 2.2a2.)
1507
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001508- The UTF-16 codec was modified to be more RFC compliant. It will now
1509 only remove BOM characters at the start of the string and then
1510 only if running in native mode (UTF-16-LE and -BE won't remove a
1511 leading BMO character).
1512
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001513- Strings now have a new method .decode() to complement the already
1514 existing .encode() method. These two methods provide direct access
1515 to the corresponding decoders and encoders of the registered codecs.
1516
1517 To enhance the usability of the .encode() method, the special
1518 casing of Unicode object return values was dropped (Unicode objects
1519 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001520
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001521 Both methods will now return whatever the codec in charge of the
1522 requested encoding returns as object, e.g. Unicode codecs will
1523 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1524 will return u"äöü"). This enables codec writer to create codecs
1525 for various simple to use conversions.
1526
1527 New codecs were added to demonstrate these new features (the .encode()
1528 and .decode() columns indicate the type of the returned objects):
1529
1530 Name | .encode() | .decode() | Description
1531 ----------------------------------------------------------------------
1532 uu | string | string | UU codec (e.g. for email)
1533 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001534 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001535 zlib | string | string | zlib compression
1536 hex | string | string | 2-byte hex codec
1537 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1538
Mark Hammond2a0af792001-05-14 03:09:36 +00001539- Some operating systems now support the concept of a default Unicode
1540 encoding for file system operations. Notably, Windows supports 'mbcs'
1541 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001542 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001543 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001544
1545 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001546 functions that return filenames (such as os.listdir()) to return Python
1547 string objects pre-encoded using the default file system encoding for
1548 the platform. As this encoding is likely to be different from Python's
1549 default encoding, converting this name to a Unicode object before passing
1550 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001551 would attempt to use its default encoding (generally ASCII) rather than
1552 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001553
Tim Petersa814db52001-05-14 07:05:58 +00001554 In general, this change simply removes surprises when working with
1555 Unicode and the file system, making these operations work as you expect,
1556 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001557 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001558
Tim Peters61dff2b2001-05-08 15:43:37 +00001559- Float (and complex) literals in source code were evaluated to full
1560 precision only when running from a .py file; the same code loaded from a
1561 .pyc (or .pyo) file could suffer numeric differences starting at about the
1562 12th significant decimal digit. For example, on a machine with IEEE-754
1563 floating arithmetic,
1564
1565 x = 9007199254740992.0
1566 print long(x)
1567
1568 printed 9007199254740992 if run directly from .py, but 9007199254740000
1569 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1570 str(float) instead of repr(float) when building code objects. marshal
1571 now uses repr(float) instead, which should reproduce floats to full
1572 machine precision (assuming the platform C float<->string I/O conversion
1573 functions are of good quality).
1574
1575 This may cause floating-point results to change in some cases, and
1576 usually for the better, but may also cause numerically unstable
1577 algorithms to break.
1578
Tim Peters2f228e72001-05-13 00:19:31 +00001579- The implementation of dicts suffers fewer collisions, which has speed
1580 benefits. However, the order in which dict entries appear in dict.keys(),
1581 dict.values() and dict.items() may differ from previous releases for a
1582 given dict. Nothing is defined about this order, so no program should
1583 rely on it. Nevertheless, it's easy to write test cases that rely on the
1584 order by accident, typically because of printing the str() or repr() of a
1585 dict to an "expected results" file. See Lib/test/test_support.py's new
1586 sortdict(dict) function for a simple way to display a dict in sorted
1587 order.
1588
Tim Peters7a3bfc32001-06-12 01:22:22 +00001589- Many other small changes to dicts were made, resulting in faster
1590 operation along the most common code paths.
1591
Guido van Rossum10315822001-05-01 20:54:30 +00001592- Dictionary objects now support the "in" operator: "x in dict" means
1593 the same as dict.has_key(x).
1594
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001595- The update() method of dictionaries now accepts generic mapping
1596 objects. Specifically the argument object must support the .keys()
1597 and __getitem__() methods. This allows you to say, for example,
1598 {}.update(UserDict())
1599
Guido van Rossum10315822001-05-01 20:54:30 +00001600- Iterators were added; this is a generalized way of providing values
1601 to a for loop. See PEP 234. There's a new built-in function iter()
1602 to return an iterator. There's a new protocol to get the next value
1603 from an iterator using the next() method (in Python) or the
1604 tp_iternext slot (in C). There's a new protocol to get iterators
1605 using the __iter__() method (in Python) or the tp_iter slot (in C).
1606 Iterating (i.e. a for loop) over a dictionary generates its keys.
1607 Iterating over a file generates its lines.
1608
Tim Petersf553f892001-05-01 20:45:31 +00001609- The following functions were generalized to work nicely with iterator
1610 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001611 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001612 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1613 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001614 join() method of strings
1615 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001616 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1617 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001618 right-hand side of assignment statements with multiple targets, such as
1619 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001620
Tim Petersd85e1022001-05-11 21:51:48 +00001621- Accessing module attributes is significantly faster (for example,
1622 random.random or os.path or yourPythonModule.yourAttribute).
1623
Tim Peterse63415e2001-05-08 04:38:29 +00001624- Comparing dictionary objects via == and != is faster, and now works even
1625 if the keys and values don't support comparisons other than ==.
1626
Tim Peters95bf9392001-05-10 08:32:44 +00001627- Comparing dictionaries in ways other than == and != is slower: there were
1628 insecurities in the dict comparison implementation that could cause Python
1629 to crash if the element comparison routines for the dict keys and/or
1630 values mutated the dicts. Making the code bulletproof slowed it down.
1631
Tim Peterseb28ef22001-06-02 05:27:19 +00001632- Collisions in dicts are resolved via a new approach, which can help
1633 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001634 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001635 faster now. Thanks to Christian Tismer for pointing out the cause and
1636 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001637
Tim Peters52e155e2001-06-16 05:42:57 +00001638- repr() is much faster for large containers (dict, list, tuple).
1639
1640
Tim Petersa814db52001-05-14 07:05:58 +00001641Library
1642
Fred Drake960fdf92001-07-20 18:38:26 +00001643- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1644 were added to the string module. These a locale-indenpendent
1645 constants, unlike letters, lowercase, and uppercase. These are now
1646 use in appropriate locations in the standard library.
1647
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001648- The flags used in dlopen calls can now be configured using
1649 sys.setdlopenflags and queried using sys.getdlopenflags.
1650
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001651- Fredrik Lundh's xmlrpclib is now a standard library module. This
1652 provides full client-side XML-RPC support. In addition,
1653 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1654 one asyncore-based). Thanks to Eric Raymond for the documentation.
1655
Guido van Rossum643d3912001-07-05 14:46:25 +00001656- The xrange() object is simplified: it no longer supports slicing,
1657 repetition, comparisons, efficient 'in' checking, the tolist()
1658 method, or the start, stop and step attributes. See PEP 260.
1659
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001660- A new function fnmatch.filter to filter lists of file names was added.
1661
Barry Warsawffd674d2001-05-22 16:00:10 +00001662- calendar.py uses month and day names based on the current locale.
1663
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001664- strop is now *really* obsolete (this was announced before with 1.6),
1665 and issues DeprecationWarning when used (except for the four items
1666 that are still imported into string.py).
1667
Tim Petersa814db52001-05-14 07:05:58 +00001668- Cookie.py now sorts key+value pairs by key in output strings.
1669
1670- pprint.isrecursive(object) didn't correctly identify recursive objects.
1671 Now it does.
1672
Tim Peters95b3f782001-05-14 18:39:41 +00001673- pprint functions now much faster for large containers (tuple, list, dict).
1674
Tim Peters7b9542a2001-06-10 23:40:19 +00001675- New 'q' and 'Q' format codes in the struct module, corresponding to C
1676 types "long long" and "unsigned long long" (on Windows, __int64). In
1677 native mode, these can be used only when the platform C compiler supports
1678 these types (when HAVE_LONG_LONG is #define'd by the Python config
1679 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001680 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1681 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001682
Guido van Rossum83213cc2001-06-12 16:48:52 +00001683- The site module installs a new built-in function 'help' that invokes
1684 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1685 it displays a message reminding the user to use 'help()' or
1686 'help(object)'.
1687
Tim Petersa814db52001-05-14 07:05:58 +00001688Tests
1689
1690- New test_mutants.py runs dict comparisons where the key and value
1691 comparison operators mutute the dicts randomly during comparison. This
1692 rapidly causes Python to crash under earlier releases (not for the faint
1693 of heart: it can also cause Win9x to freeze or reboot!).
1694
1695- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001696 pprint.isreadable() return sensible results. Also verifies that simple
1697 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001698
Tim Peters4324aa32001-05-28 22:30:08 +00001699C API
1700
1701- Removed the unused last_is_sticky argument from the internal
1702 _PyTuple_Resize(). If this affects you, you were cheating.
1703
1704
Guido van Rossum55a78992001-07-17 17:22:32 +00001705======================================================================
1706
1707
Guido van Rossumffe13be2001-04-16 18:46:45 +00001708What's New in Python 2.1 (final)?
1709=================================
1710
1711We only changed a few things since the last release candidate, all in
1712Python library code:
1713
1714- A bug in the locale module was fixed that affected locales which
1715 define no grouping for numeric formatting.
1716
1717- A few bugs in the weakref module's implementations of weak
1718 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1719 and the test suite was updated to check for these bugs.
1720
1721- An old bug in the os.path.walk() function (introduced in Python
1722 2.0!) was fixed: a non-existent file would cause an exception
1723 instead of being ignored.
1724
1725- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1726 PyChecker.
1727
1728
Guido van Rossum5b08f132001-04-16 02:05:23 +00001729What's New in Python 2.1c2?
1730===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001731
Guido van Rossum5b08f132001-04-16 02:05:23 +00001732A flurry of small changes, and one showstopper fixed in the nick of
1733time made it necessary to release another release candidate. The list
1734here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001735
Guido van Rossum5b08f132001-04-16 02:05:23 +00001736Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001737
Guido van Rossum5b08f132001-04-16 02:05:23 +00001738- Tim discovered a nasty bug in the dictionary code, caused by
1739 PyDict_Next() calling dict_resize(), and the GC code's use of
1740 PyDict_Next() violating an assumption in dict_items(). This was
1741 fixed with considerable amounts of band-aid, but the net effect is a
1742 saner and more robust implementation.
1743
1744- Made a bunch of symbols static that were accidentally global.
1745
1746Build and Ports
1747
1748- The setup.py script didn't check for a new enough version of zlib
1749 (1.1.3 is needed). Now it does.
1750
1751- Changed "make clean" target to also remove shared libraries.
1752
1753- Added a more general warning about the SGI Irix optimizer to README.
1754
1755Library
1756
1757- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1758 omitted the slash between host and file.html.
1759
1760- The mailbox module's _Mailbox class contained a completely broken
1761 and undocumented seek() method. Ripped it out.
1762
1763- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1764 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1765
1766- Fixed a few last-minute bugs in unittest.
1767
1768Extensions
1769
1770- Reverted the patch to the OpenSSL code in socketmodule.c to support
1771 RAND_status() and the EGD, and the subsequent patch that tried to
1772 fix it for pre-0.9.5 versions; the problem with the patch is that on
1773 some systems it issues a warning whenever socket is imported, and
1774 that's unacceptable.
1775
1776Tests
1777
1778- Fixed the pickle tests to work with "import test.test_pickle".
1779
1780- Tweaked test_locale.py to actually run the test Windows.
1781
1782- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1783 not "wb" (which is not a valid mode at all).
1784
1785- Fix pstats browser crashes. Import readline if it exists to make
1786 the user interface nicer.
1787
1788- Add "import thread" to the top of test modules that import the
1789 threading module (test_asynchat and test_threadedtempfile). This
1790 prevents test failures caused by a broken threading module resulting
1791 from a previously caught failed import.
1792
1793- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1794 needed on some platforms (e.g. Solaris 8) when the tests are run
1795 twice in succession.
1796
1797- Skip rather than fail test_sunaudiodev if no audio device is found.
1798
1799
1800What's New in Python 2.1c1?
1801===========================
1802
1803This list was significantly updated when 2.1c2 was released; the 2.1c1
1804release didn't mention most changes that were actually part of 2.1c1:
1805
1806Legal
1807
1808- Copyright was assigned to the Python Software Foundation (PSF) and a
1809 PSF license (very similar to the CNRI license) was added.
1810
1811- The CNRI copyright notice was updated to include 2001.
1812
1813Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001814
Guido van Rossumc9932722001-04-12 02:31:27 +00001815- After a public outcry, assignment to __debug__ is no longer illegal;
1816 instead, a warning is issued. It will become illegal in 2.2.
1817
Guido van Rossum5b08f132001-04-16 02:05:23 +00001818- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1819 "%#x" now always prepends "0x", even if the value is zero.
1820
1821- Fixed some nits in the bytecode compiler.
1822
1823- Fixed core dumps when calling certain kinds of non-functions.
1824
1825- Fixed various core dumps caused by reference count bugs.
1826
1827Build and Ports
1828
1829- Use INSTALL_SCRIPT to install script files.
1830
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001831- New port: SCO Unixware 7, by Billy G. Allie.
1832
Guido van Rossum5b08f132001-04-16 02:05:23 +00001833- Updated RISCOS port.
1834
1835- Updated BeOS port and notes.
1836
1837- Various other porting problems resolved.
1838
1839Library
1840
1841- The TERMIOS and SOCKET modules are now truly obsolete and
1842 unnecessary. Their symbols are incorporated in the termios and
1843 socket modules.
1844
1845- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1846 better tests for pickling.
1847
1848- threading: make Condition.wait() robust against KeyboardInterrupt.
1849
1850- zipfile: add support to zipfile to support opening an archive
1851 represented by an open file rather than a file name. Fix bug where
1852 the archive was not properly closed. Fixed a bug in this bugfix
1853 where flush() was called for a read-only file.
1854
1855- imputil: added an uninstall() method to the ImportManager.
1856
1857- Canvas: fixed bugs in lower() and tkraise() methods.
1858
1859- SocketServer: API change (added overridable close_request() method)
1860 so that the TCP server can explicitly close the request.
1861
1862- pstats: Eric Raymond added a simple interactive statistics browser,
1863 invoked when the module is run as a script.
1864
1865- locale: fixed a problem in format().
1866
1867- webbrowser: made it work when the BROWSER environment variable has a
1868 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1869 KDE 2. Fixed some other nits.
1870
1871- unittest: changes to allow using a different exception than
1872 AssertionError, and added a few more function aliases. Some other
1873 small changes.
1874
1875- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1876
1877- asynchat: fixed a critical bug in asynchat that slipped through the
1878 2.1b2 release. Fixed another rare bug.
1879
1880- Fix some unqualified except: clauses (always a bad code example).
1881
1882XML
1883
1884- pyexpat: new API get_version_string().
1885
1886- Fixed some minidom bugs.
1887
1888Extensions
1889
1890- Fixed a core dump in _weakref. Removed the weakref.mapping()
1891 function (it adds nothing to the API).
1892
1893- Rationalized the use of header files in the readline module, to make
1894 it compile (albeit with some warnings) with the very recent readline
1895 4.2, without breaking for earlier versions.
1896
1897- Hopefully fixed a buffering problem in linuxaudiodev.
1898
1899- Attempted a fix to make the OpenSSL support in the socket module
1900 work again with pre-0.9.5 versions of OpenSSL.
1901
1902Tests
1903
1904- Added a test case for asynchat and asyncore.
1905
1906- Removed coupling between tests where one test failing could break
1907 another.
1908
1909Tools
1910
1911- Ping added an interactive help browser to pydoc, fixed some nits
1912 in the rest of the pydoc code, and added some features to his
1913 inspect module.
1914
1915- An updated python-mode.el version 4.1 which integrates Ken
1916 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1917 much nicer in XEmacs and Emacs. When stepping through your program
1918 with pdb, in either the shell window or the *Python* window, the
1919 source file and line will be tracked by an arrow. Very cool!
1920
1921- IDLE: syntax warnings in interactive mode are changed into errors.
1922
1923- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001924 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001925
1926- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001927
Barry Warsaw11e89c72001-04-11 20:37:57 +00001928
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001929What's New in Python 2.1 beta 2?
1930================================
1931
Guido van Rossum053ae352001-03-22 14:17:21 +00001932(Unlisted are many fixed bugs, more documentation, etc.)
1933
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001934Core language, builtins, and interpreter
1935
Guido van Rossum053ae352001-03-22 14:17:21 +00001936- The nested scopes work (enabled by "from __future__ import
1937 nested_scopes") is completed; in particular, the future now extends
1938 into code executed through exec, eval() and execfile(), and into the
1939 interactive interpreter.
1940
1941- When calling a base class method (e.g. BaseClass.__init__(self)),
1942 this is now allowed even if self is not strictly spoken a class
1943 instance (e.g. when using metaclasses or the Don Beaudry hook).
1944
1945- Slice objects are now comparable but not hashable; this prevents
1946 dict[:] from being accepted but meaningless.
1947
1948- Complex division is now calculated using less braindead algorithms.
1949 This doesn't change semantics except it's more likely to give useful
1950 results in extreme cases. Complex repr() now uses full precision
1951 like float repr().
1952
1953- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1954
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001955- It is illegal to assign to the name __debug__, which is set when the
1956 interpreter starts. It is effectively a compile-time constant.
1957
1958- A warning will be issued if a global statement for a variable
1959 follows a use or assignment of that variable.
1960
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001961Standard library
1962
Guido van Rossum053ae352001-03-22 14:17:21 +00001963- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1964 inspired by JUnit), is now part of the standard library. You now
1965 have a choice of two testing frameworks: unittest requires you to
1966 write testcases as separate code, doctest gathers them from
1967 docstrings. Both approaches have their advantages and
1968 disadvantages.
1969
1970- A new module Tix was added, which wraps the Tix extension library
1971 for Tk. With that module, it is not necessary to statically link
1972 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1973 require" command. See Demo/tix/.
1974
1975- tzparse.py is now obsolete.
1976
1977- In gzip.py, the seek() and tell() methods are removed -- they were
1978 non-functional anyway, and it's better if callers can test for their
1979 existence with hasattr().
1980
1981Python/C API
1982
1983- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1984 that's already in the dictionary during a PyDict_Next() iteration.
1985 This used to fail occasionally when a dictionary resize operation
1986 could be triggered that would rehash all the keys. All other
1987 modifications to the dictionary are still off-limits during a
1988 PyDict_Next() iteration!
1989
1990- New extended APIs related to passing compiler variables around.
1991
1992- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1993 implement isinstance() and issubclass().
1994
1995- Py_BuildValue() now has a "D" conversion to create a Python complex
1996 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001997
Fred Drake4e262a92001-03-22 18:26:47 +00001998- Extensions types which support weak references must now set the
1999 field allocated for the weak reference machinery to NULL themselves;
2000 this is done to avoid the cost of checking each object for having a
2001 weakly referencable type in PyObject_INIT(), since most types are
2002 not weakly referencable.
2003
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002004- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2005 free variables and cell variables to and from the frame's f_locals.
2006
2007- Variants of several functions defined in pythonrun.h have been added
2008 to support the nested_scopes future statement. The variants all end
2009 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2010 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2011 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002012 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002013
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002014Distutils
2015
2016- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2017 into the release tree.
2018
Tim Peters0e57abf2001-05-02 07:39:38 +00002019- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002020 (an uninstaller, more customization of the installer's display)
2021
2022- from Jack Jansen: added Mac-specific code to generate a dialog for
2023 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002024 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002025 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002026
2027- added 'platforms' and 'keywords' to the set of metadata that can be
2028 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002029
2030- applied patches from Jason Tishler to make the compiler class work with
2031 Cygwin.
2032
2033
Tim Peters2fe289a2001-03-01 22:19:38 +00002034What's New in Python 2.1 beta 1?
2035================================
Tim Petersd66595f2001-02-04 03:09:53 +00002036
2037Core language, builtins, and interpreter
2038
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002039- Following an outcry from the community about the amount of code
2040 broken by the nested scopes feature introduced in 2.1a2, we decided
2041 to make this feature optional, and to wait until Python 2.2 (or at
2042 least 6 months) to make it standard. The option can be enabled on a
2043 per-module basis by adding "from __future__ import nested_scopes" at
2044 the beginning of a module (before any other statements, but after
2045 comments and an optional docstring). See PEP 236 (Back to the
2046 __future__) for a description of the __future__ statement. PEP 227
2047 (Statically Nested Scopes) has been updated to reflect this change,
2048 and to clarify the semantics in a number of endcases.
2049
2050- The nested scopes code, when enabled, has been hardened, and most
2051 bugs and memory leaks in it have been fixed.
2052
2053- Compile-time warnings are now generated for a number of conditions
2054 that will break or change in meaning when nested scopes are enabled:
2055
2056 - Using "from...import *" or "exec" without in-clause in a function
2057 scope that also defines a lambda or nested function with one or
2058 more free (non-local) variables. The presence of the import* or
2059 bare exec makes it impossible for the compiler to determine the
2060 exact set of local variables in the outer scope, which makes it
2061 impossible to determine the bindings for free variables in the
2062 inner scope. To avoid the warning about import *, change it into
2063 an import of explicitly name object, or move the import* statement
2064 to the global scope; to avoid the warning about bare exec, use
2065 exec...in... (a good idea anyway -- there's a possibility that
2066 bare exec will be deprecated in the future).
2067
2068 - Use of a global variable in a nested scope with the same name as a
2069 local variable in a surrounding scope. This will change in
2070 meaning with nested scopes: the name in the inner scope will
2071 reference the variable in the outer scope rather than the global
2072 of the same name. To avoid the warning, either rename the outer
2073 variable, or use a global statement in the inner function.
2074
Neil Schemenauera35c6882001-02-27 04:45:05 +00002075- An optional object allocator has been included. This allocator is
2076 optimized for Python objects and should be faster and use less memory
2077 than the standard system allocator. It is not enabled by default
2078 because of possible thread safety problems. The allocator is only
2079 protected by the Python interpreter lock and it is possible that some
2080 extension modules require a thread safe allocator. The object
2081 allocator can be enabled by providing the "--with-pymalloc" option to
2082 configure.
2083
Tim Petersd66595f2001-02-04 03:09:53 +00002084Standard library
2085
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002086- pyexpat now detects the expat version if expat.h defines it. A
2087 number of additional handlers are provided, which are only available
2088 since expat 1.95. In addition, the methods SetParamEntityParsing and
2089 GetInputContext of Parser objects are available with 1.95.x
2090 only. Parser objects now provide the ordered_attributes and
2091 specified_attributes attributes. A new module expat.model was added,
2092 which offers a number of additional constants if 1.95.x is used.
2093
2094- xml.dom offers the new functions registerDOMImplementation and
2095 getDOMImplementation.
2096
2097- xml.dom.minidom offers a toprettyxml method. A number of DOM
2098 conformance issues have been resolved. In particular, Element now
2099 has an hasAttributes method, and the handling of namespaces was
2100 improved.
2101
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002102- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2103 getting information about live Python code, and pydoc.py, a module
2104 for interactively converting docstrings to HTML or text.
2105 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002106 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002107 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2108 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002109
Tim Peters1eff7962001-03-01 02:31:33 +00002110- New library module difflib.py, primarily packaging the SequenceMatcher
2111 class at the heart of the popular ndiff.py file-comparison tool.
2112
2113- doctest.py (a framework for verifying Python code examples in docstrings)
2114 is now part of the std library.
2115
Tim Petersd66595f2001-02-04 03:09:53 +00002116Windows changes
2117
Guido van Rossume3955a82001-03-02 14:05:59 +00002118- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2119 small GUI that lets you browse the module docstrings using your
2120 default web browser.
2121
Tim Peters1eff7962001-03-01 02:31:33 +00002122- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2123 Platforms) is implemented. See
2124
2125 http://python.sourceforge.net/peps/pep-0235.html
2126
2127 for full details, especially the "Current Lower-Left Semantics" section.
2128 The new Windows import rules are simpler than before:
2129
2130 A. If the PYTHONCASEOK environment variable exists, same as
2131 before: silently accept the first case-insensitive match of any
2132 kind; raise ImportError if none found.
2133
2134 B. Else search sys.path for the first case-sensitive match; raise
2135 ImportError if none found.
2136
2137 The same rules have been implented on other platforms with case-
2138 insensitive but case-preserving filesystems too (including Cygwin, and
2139 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002140
Tim Peters25a9ce32001-02-19 07:06:36 +00002141- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2142 what it's supposed to do (and does do under NT and 2000) via direct
2143 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002144 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002145 all Win9x systems before.
2146
Tim Peters1eff7962001-03-01 02:31:33 +00002147- Build: Subproject _test (effectively) renamed to _testcapi.
2148
Tim Peters2fe289a2001-03-01 22:19:38 +00002149New platforms
2150
2151- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2152 Thanks to Steven Majewski!
2153
2154- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2155 Tishler!
2156
Guido van Rossum9089b272001-03-02 06:49:50 +00002157- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2158 Schwertberger! See RISCOS/README for more information -- it seems
2159 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002160 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002161
Tim Peters25a9ce32001-02-19 07:06:36 +00002162
Tim Petersd7b5e882001-01-25 03:36:26 +00002163What's New in Python 2.1 alpha 2?
2164=================================
Tim Peters40ead762001-01-27 05:35:26 +00002165
Tim Petersd7b5e882001-01-25 03:36:26 +00002166Core language, builtins, and interpreter
2167
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002168- Scopes nest. If a name is used in a function or class, but is not
2169 local, the definition in the nearest enclosing function scope will
2170 be used. One consequence of this change is that lambda statements
2171 could reference variables in the namespaces where the lambda is
2172 defined. In some unusual cases, this change will break code.
2173
2174 In all previous version of Python, names were resolved in exactly
2175 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002176 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002177 function A is defined within a function B, the names bound in B are
2178 not visible in A. The new rules make names bound in B visible in A,
2179 unless A contains a name binding that hides the binding in B.
2180
2181 Section 4.1 of the reference manual describes the new scoping rules
2182 in detail. The test script in Lib/test/test_scope.py demonstrates
2183 some of the effects of the change.
2184
2185 The new rules will cause existing code to break if it defines nested
2186 functions where an outer function has local variables with the same
2187 name as globals or builtins used by the inner function. Example:
2188
2189 def munge(str):
2190 def helper(x):
2191 return str(x)
2192 if type(str) != type(''):
2193 str = helper(str)
2194 return str.strip()
2195
2196 Under the old rules, the name str in helper() is bound to the
2197 builtin function str(). Under the new rules, it will be bound to
2198 the argument named str and an error will occur when helper() is
2199 called.
2200
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002201- The compiler will report a SyntaxError if "from ... import *" occurs
2202 in a function or class scope. The language reference has documented
2203 that this case is illegal, but the compiler never checked for it.
2204 The recent introduction of nested scope makes the meaning of this
2205 form of name binding ambiguous. In a future release, the compiler
2206 may allow this form when there is no possibility of ambiguity.
2207
Tim Peters40ead762001-01-27 05:35:26 +00002208- repr(string) is easier to read, now using hex escapes instead of octal,
2209 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2210
2211 >>> "\texample \r\n" + chr(0) + chr(255)
2212 '\texample \r\n\x00\xff' # in 2.1
2213 '\011example \015\012\000\377' # in 2.0
2214
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002215- Functions are now compared and hashed by identity, not by value, since
2216 the func_code attribute is writable.
2217
Fred Drakefb9d7122001-02-01 20:00:40 +00002218- Weak references (PEP 205) have been added. This involves a few
2219 changes in the core, an extension module (_weakref), and a Python
2220 module (weakref). The weakref module is the public interface. It
2221 includes support for "explicit" weak references, proxy objects, and
2222 mappings with weakly held values.
2223
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002224- A 'continue' statement can now appear in a try block within the body
2225 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002226 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002227
Tim Petersd7b5e882001-01-25 03:36:26 +00002228Standard library
2229
Barry Warsaw30dbd142001-01-31 22:14:01 +00002230- mailbox.py now has a new class, PortableUnixMailbox which is
2231 identical to UnixMailbox but uses a more portable scheme for
2232 determining From_ separators. Also, the constructors for all the
2233 classes in this module have a new optional `factory' argument, which
2234 is a callable used when new message classes must be instantiated by
2235 the next() method.
2236
Tim Petersd7b5e882001-01-25 03:36:26 +00002237- random.py is now self-contained, and offers all the functionality of
2238 the now-deprecated whrandom.py. See the docs for details. random.py
2239 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002240 and restoring the internal state of the generator; and jumpahead(n),
2241 for quickly forcing the internal state to be the same as if n calls to
2242 random() had been made. The latter is particularly useful for multi-
2243 threaded programs, creating one instance of the random.Random() class for
2244 each thread, then using .jumpahead() to force each instance to use a
2245 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002246
Tim Peters0de88fc2001-02-01 04:59:18 +00002247- random.py's seed() function is new. For bit-for-bit compatibility with
2248 prior releases, use the whseed function instead. The new seed function
2249 addresses two problems: (1) The old function couldn't produce more than
2250 about 2**24 distinct internal states; the new one about 2**45 (the best
2251 that can be done in the Wichmann-Hill generator). (2) The old function
2252 sometimes produced identical internal states when passed distinct
2253 integers, and there was no simple way to predict when that would happen;
2254 the new one guarantees to produce distinct internal states for all
2255 arguments in [0, 27814431486576L).
2256
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002257- The socket module now supports raw packets on Linux. The socket
2258 family is AF_PACKET.
2259
Tim Peters9ea17ac2001-02-02 05:57:15 +00002260- test_capi.py is a start at running tests of the Python C API. The tests
2261 are implemented by the new Modules/_testmodule.c.
2262
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002263- A new extension module, _symtable, provides provisional access to the
2264 internal symbol table used by the Python compiler. A higher-level
2265 interface will be added on top of _symtable in a future release.
2266
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002267- Removed the obsolete soundex module.
2268
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002269- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2270 the isSameNode method; NamedNodeMap the get method.
2271
2272- xml.sax.expatreader supports the lexical handler property; it
2273 generates comment, startCDATA, and endCDATA events.
2274
Tim Petersee826f82001-01-31 19:39:44 +00002275Windows changes
2276
2277- Build procedure: the zlib project is built in a different way that
2278 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002279 the zlib binary used. See PCbuild\readme.txt for details. Your old
2280 zlib-related directories can be deleted; you'll need to download fresh
2281 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002282
Tim Peters9ea17ac2001-02-02 05:57:15 +00002283- Build: New subproject _test for the benefit of test_capi.py (see above).
2284
Tim Petersb16c56f2001-02-02 21:24:51 +00002285- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2286 interface to some Python compiler internals).
2287
2288- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002289 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002290
Tim Petersa3a3a032000-11-30 05:22:44 +00002291What's New in Python 2.1 alpha 1?
2292=================================
2293
2294Core language, builtins, and interpreter
2295
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002296- There is a new Unicode companion to the PyObject_Str() API
2297 called PyObject_Unicode(). It behaves in the same way as the
2298 former, but assures that the returned value is an Unicode object
2299 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002300
Guido van Rossumf98eda02001-01-17 15:54:45 +00002301- The comparison operators support "rich comparison overloading" (PEP
2302 207). C extension types can provide a rich comparison function in
2303 the new tp_richcompare slot in the type object. The cmp() function
2304 and the C function PyObject_Compare() first try the new rich
2305 comparison operators before trying the old 3-way comparison. There
2306 is also a new C API PyObject_RichCompare() (which also falls back on
2307 the old 3-way comparison, but does not constrain the outcome of the
2308 rich comparison to a Boolean result).
2309
2310 The rich comparison function takes two objects (at least one of
2311 which is guaranteed to have the type that provided the function) and
2312 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2313 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2314 object, which may be NotImplemented (in which case the tp_compare
2315 slot function is used as a fallback, if defined).
2316
2317 Classes can overload individual comparison operators by defining one
2318 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002319 __ge__. There are no explicit "reflected argument" versions of
2320 these; instead, __lt__ and __gt__ are each other's reflection,
2321 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2322 reflection (similar at the C level). No other implications are
2323 made; in particular, Python does not assume that == is the Boolean
2324 inverse of !=, or that < is the Boolean inverse of >=. This makes
2325 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002326
2327 Classes or types that want to implement (in)equality tests but not
2328 the ordering operators (i.e. unordered types) should implement ==
2329 and !=, and raise an error for the ordering operators.
2330
Guido van Rossuma88479f2001-01-18 14:28:08 +00002331 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002332 Boolean; e.g. a matrix type might want to return a matrix of bits
2333 for A < B, giving elementwise comparisons. Such types should ensure
2334 that any interpretation of their value in a Boolean context raises
2335 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2336 at the C level) to always raise an exception.
2337
Guido van Rossuma88479f2001-01-18 14:28:08 +00002338- Complex numbers use rich comparisons to define == and != but raise
2339 an exception for <, <=, > and >=. Unfortunately, this also means
2340 that cmp() of two complex numbers raises an exception when the two
2341 numbers differ. Since it is not mathematically meaningful to compare
2342 complex numbers except for equality, I hope that this doesn't break
2343 too much code.
2344
Tim Peters3389f192001-02-18 08:48:49 +00002345- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002346 not defined by the language, other than that it's arbitrary but
2347 consistent (see the Reference Manual). An implementation detail changed
2348 in 2.1a1 such that None now compares less than any other object. Code
2349 relying on this new behavior (like code that relied on the previous
2350 behavior) does so at its own risk.
2351
Barry Warsaw573b5412001-01-15 20:43:18 +00002352- Functions and methods now support getting and setting arbitrarily
2353 named attributes (PEP 232). Functions have a new __dict__
2354 (a.k.a. func_dict) which hold the function attributes. Methods get
2355 and set attributes on their underlying im_func. It is a TypeError
2356 to set an attribute on a bound method.
2357
Guido van Rossum051e3352001-01-15 19:11:10 +00002358- The xrange() object implementation has been improved so that
2359 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2360 limitation that in this case len(xrange(sys.maxint)) can't be
2361 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2362 work fine as long as the index i doesn't actually reach 2**31.
2363 (Python uses regular ints for sequence and string indices; fixing
2364 that is much more work.)
2365
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002366- Two changes to from...import:
2367
Guido van Rossumba381232001-02-03 15:06:40 +00002368 1) "from M import X" now works even if (after loading module M)
2369 sys.modules['M'] is not a real module; it's basically a getattr()
2370 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002371
2372 2) "from M import *" now looks for M.__all__ to decide which names to
2373 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2374 filters out names starting with '_' as before. Whether or not
2375 __all__ exists, there's no restriction on the type of M.
2376
Guido van Rossumf61f1662001-01-10 20:13:55 +00002377- File objects have a new method, xreadlines(). This is the fastest
2378 way to iterate over all lines in a file:
2379
2380 for line in file.xreadlines():
2381 ...do something to line...
2382
2383 See the xreadlines module (mentioned below) for how to do this for
2384 other file-like objects.
2385
2386- Even if you don't use file.xreadlines(), you may expect a speedup on
2387 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002388 quite a bit in platform-specific ways: on systems (like Linux) that
2389 support flockfile(), getc_unlocked(), and funlockfile(), those are
2390 used by default. On systems (like Windows) without getc_unlocked(),
2391 a complicated (but still thread-safe) method using fgets() is used by
2392 default.
2393
Tim Petersd52269b2001-01-25 06:23:18 +00002394 You can force use of the fgets() method by #define'ing
2395 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002396 getc_unlocked()).
2397
Tim Petersd52269b2001-01-25 06:23:18 +00002398 You can force fgets() not to be used by #define'ing
2399 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002400 test_bufio.py fails -- and let us know if it does!).
2401
2402- In addition, the fileinput module, while still slower than the other
2403 methods on most platforms, has been sped up too, by using
2404 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002405
2406- Support for run-time warnings has been added, including a new
2407 command line option (-W) to specify the disposition of warnings.
2408 See the description of the warnings module below.
2409
2410- Extensive changes have been made to the coercion code. This mostly
2411 affects extension modules (which can now implement mixed-type
2412 numerical operators without having to use coercion), but
2413 occasionally, in boundary cases the coercion semantics have changed
2414 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002415 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002416 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002417 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002418
Guido van Rossumf98eda02001-01-17 15:54:45 +00002419- In connection with the coercion changes, a new built-in singleton
2420 object, NotImplemented is defined. This can be returned for
2421 operations that wish to indicate they are not implemented for a
2422 particular combination of arguments. From C, this is
2423 Py_NotImplemented.
2424
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002425- The interpreter accepts now bytecode files on the command line even
2426 if they do not have a .pyc or .pyo extension. On Linux, after executing
2427
Martin v. Löwise214baa2001-02-04 22:37:56 +00002428import imp,sys,string
2429magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2430reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2431open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002432
2433 any byte code file can be used as an executable (i.e. as an argument
2434 to execve(2)).
2435
Tim Peters9940b802000-12-01 07:59:35 +00002436- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002437 character. In 1.6 and earlier, they never produced a sign,
2438 and raised an error if the value of the long was too large
2439 to fit in a Python int. In 2.0, they produced a sign if and
2440 only if too large to fit in an int. This was inconsistent
2441 across platforms (because the size of an int varies across
2442 platforms), and inconsistent with hex() and oct(). Example:
2443
2444 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002445 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002446 'ffffffbe' # in 2.0 and before, on 32-bit machines
2447 >>> hex(-0x42L)
2448 '-0x42L' # in all versions of Python
2449
Tim Peters9940b802000-12-01 07:59:35 +00002450 The behavior of %d formats for negative Python longs remains
2451 the same as in 2.0 (although in 1.6 and before, they raised
2452 an error if the long didn't fit in a Python int).
2453
2454 %u formats don't make sense for Python longs, but are allowed
2455 and treated the same as %d in 2.1. In 2.0, a negative long
2456 formatted via %u produced a sign if and only if too large to
2457 fit in an int. In 1.6 and earlier, a negative long formatted
2458 via %u raised an error if it was too big to fit in an int.
2459
Guido van Rossum3661d392000-12-12 22:10:31 +00002460- Dictionary objects have an odd new method, popitem(). This removes
2461 an arbitrary item from the dictionary and returns it (in the form of
2462 a (key, value) pair). This can be useful for algorithms that use a
2463 dictionary as a bag of "to do" items and repeatedly need to pick one
2464 item. Such algorithms normally end up running in quadratic time;
2465 using popitem() they can usually be made to run in linear time.
2466
Tim Peters36cdad12000-12-29 02:06:45 +00002467Standard library
2468
Thomas Woutersfe385252001-01-19 23:16:56 +00002469- In the time module, the time argument to the functions strftime,
2470 localtime, gmtime, asctime and ctime is now optional, defaulting to
2471 the current time (in the local timezone).
2472
Guido van Rossumda91f222001-01-15 16:36:08 +00002473- The ftplib module now defaults to passive mode, which is deemed a
2474 more useful default given that clients are often inside firewalls
2475 these days. Note that this could break if ftplib is used to connect
2476 to a *server* that is inside a firewall, from outside; this is
2477 expected to be a very rare situation. To fix that, you can call
2478 ftp.set_pasv(0).
2479
Martin v. Löwis10a27872001-01-13 09:54:41 +00002480- The module site now treats .pth files not only for path configuration,
2481 but also supports extensions to the initialization code: Lines starting
2482 with import are executed.
2483
Guido van Rossumf61f1662001-01-10 20:13:55 +00002484- There's a new module, warnings, which implements a mechanism for
2485 issuing and filtering warnings. There are some new built-in
2486 exceptions that serve as warning categories, and a new command line
2487 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2488 turns warnings into errors). warnings.warn(message[, category])
2489 issues a warning message; this can also be called from C as
2490 PyErr_Warn(category, message).
2491
2492- A new module xreadlines was added. This exports a single factory
2493 function, xreadlines(). The intention is that this code is the
2494 absolutely fastest way to iterate over all lines in an open
2495 file(-like) object:
2496
2497 import xreadlines
2498 for line in xreadlines.xreadlines(file):
2499 ...do something to line...
2500
2501 This is equivalent to the previous the speed record holder using
2502 file.readlines(sizehint). Note that if file is a real file object
2503 (as opposed to a file-like object), this is equivalent:
2504
2505 for line in file.xreadlines():
2506 ...do something to line...
2507
Tim Peters36cdad12000-12-29 02:06:45 +00002508- The bisect module has new functions bisect_left, insort_left,
2509 bisect_right and insort_right. The old names bisect and insort
2510 are now aliases for bisect_right and insort_right. XXX_right
2511 and XXX_left methods differ in what happens when the new element
2512 compares equal to one or more elements already in the list: the
2513 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002514 right. Code that doesn't care where equal elements end up should
2515 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002516
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002517- The new curses.panel module wraps the panel library that forms part
2518 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2519
Guido van Rossumf61f1662001-01-10 20:13:55 +00002520- The SocketServer module now sets the allow_reuse_address flag by
2521 default in the TCPServer class.
2522
2523- A new function, sys._getframe(), returns the stack frame pointer of
2524 the caller. This is intended only as a building block for
2525 higher-level mechanisms such as string interpolation.
2526
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002527- The pyexpat module supports a number of new handlers, which are
2528 available only in expat 1.2. If invocation of a callback fails, it
2529 will report an additional frame in the traceback. Parser objects
2530 participate now in garbage collection. If expat reports an unknown
2531 encoding, pyexpat will try to use a Python codec; that works only
2532 for single-byte charsets. The parser type objects is exposed as
2533 XMLParserObject.
2534
2535- xml.dom now offers standard definitions for symbolic node type and
2536 exception code constants, and a hierarchy of DOM exceptions. minidom
2537 was adjusted to use them.
2538
2539- The conformance of xml.dom.minidom to the DOM specification was
2540 improved. It detects a number of additional error cases; the
2541 previous/next relationship works even when the tree is modified;
2542 Node supports the normalize() method; NamedNodeMap, DocumentType and
2543 DOMImplementation classes were added; Element supports the
2544 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2545 method.
2546
Guido van Rossumf61f1662001-01-10 20:13:55 +00002547Build issues
2548
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002549- For Unix (and Unix-compatible) builds, configuration and building of
2550 extension modules is now greatly automated. Rather than having to
2551 edit the Modules/Setup file to indicate which modules should be
2552 built and where their include files and libraries are, a
2553 distutils-based setup.py script now takes care of building most
2554 extension modules. All extension modules built this way are built
2555 as shared libraries. Only a few modules that must be linked
2556 statically are still listed in the Setup file; you won't need to
2557 edit their configuration.
2558
2559- Python should now build out of the box on Cygwin. If it doesn't,
2560 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002561
2562- Python now always uses its own (renamed) implementation of getopt()
2563 -- there's too much variation among C library getopt()
2564 implementations.
2565
2566- C++ compilers are better supported; the CXX macro is always set to a
2567 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002568
Tim Petersd92dfe02000-12-12 01:18:41 +00002569Windows changes
2570
2571- select module: By default under Windows, a select() call
2572 can specify no more than 64 sockets. Python now boosts
2573 this Microsoft default to 512. If you need even more than
2574 that, see the MS docs (you'll need to #define FD_SETSIZE
2575 and recompile Python from source).
2576
Guido van Rossumf61f1662001-01-10 20:13:55 +00002577- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2578 subdirectory is no more!
2579
Tim Petersa3a3a032000-11-30 05:22:44 +00002580
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002581What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002582=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002583
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002584Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002585changes are in the file HISTORY. If you are making the jump directly
2586from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2587HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002588
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002589Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2590the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2591http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002592
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002593--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002594
2595======================================================================
2596
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002597What's new in 2.0 (since release candidate 1)?
2598==============================================
2599
2600Standard library
2601
2602- The copy_reg module was modified to clarify its intended use: to
2603 register pickle support for extension types, not for classes.
2604 pickle() will raise a TypeError if it is passed a class.
2605
2606- Fixed a bug in gettext's "normalize and expand" code that prevented
2607 it from finding an existing .mo file.
2608
2609- Restored support for HTTP/0.9 servers in httplib.
2610
Tim Peters989b7b92000-10-16 20:24:53 +00002611- The math module was changed to stop raising OverflowError in case of
2612 underflow, and return 0 instead in underflow cases. Whether Python
2613 used to raise OverflowError in case of underflow was platform-
2614 dependent (it did when the platform math library set errno to ERANGE
2615 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002616
2617- Fixed a bug in StringIO that occurred when the file position was not
2618 at the end of the file and write() was called with enough data to
2619 extend past the end of the file.
2620
2621- Fixed a bug that caused Tkinter error messages to get lost on
2622 Windows. The bug was fixed by replacing direct use of
2623 interp->result with Tcl_GetStringResult(interp).
2624
2625- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2626 redirect response.
2627
2628- Several changes were made to distutils: Some debugging code was
2629 removed from util. Fixed the installer used when an external zip
2630 program (like WinZip) is not found; the source code for this
2631 installer is in Misc/distutils. check_lib() was modified to behave
2632 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2633 test for whether installed modules are on sys.path was changed to
2634 use both normcase() and normpath().
2635
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002636- Several minor bugs were fixed in the xml package (the minidom,
2637 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002638
2639- The regression test driver (regrtest.py) behavior when invoked with
2640 -l changed: It now reports a count of objects that are recognized as
2641 garbage but not freed by the garbage collector.
2642
Tim Peters989b7b92000-10-16 20:24:53 +00002643- The regression test for the math module was changed to test
2644 exceptional behavior when the test is run in verbose mode. Python
2645 cannot yet guarantee consistent exception behavior across platforms,
2646 so the exception part of test_math is run only in verbose mode, and
2647 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002648
2649Internals
2650
2651- PyOS_CheckStack() has been disabled on Win64, where it caused
2652 test_sre to fail.
2653
2654Build issues
2655
2656- Changed compiler flags, so that gcc is always invoked with -Wall and
2657 -Wstrict-prototypes. Users compiling Python with GCC should see
2658 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002659 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002660 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002661
Tim Petersa3a3a032000-11-30 05:22:44 +00002662- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002663
2664Tools and other miscellany
2665
2666- The compiler in Tools/compiler was updated to support the new
2667 language features introduced in 2.0: extended print statement, list
2668 comprehensions, and augmented assignments. The new compiler should
2669 also be backwards compatible with Python 1.5.2; the compiler will
2670 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002671 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002672
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002673What's new in 2.0 release candidate 1 (since beta 2)?
2674=====================================================
2675
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002676What is release candidate 1?
2677
2678We believe that release candidate 1 will fix all known bugs that we
2679intend to fix for the 2.0 final release. This release should be a bit
2680more stable than the previous betas. We would like to see even more
2681widespread testing before the final release, so we are producing this
2682release candidate. The final release will be exactly the same unless
2683any show-stopping (or brown bag) bugs are found by testers of the
2684release candidate.
2685
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002686All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002687to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002688
2689Core language, builtins, and interpreter
2690
2691- A bug that caused crashes when __coerce__ was used with augmented
2692 assignment, e.g. +=, was fixed.
2693
2694- Raise ZeroDivisionError when raising zero to a negative number,
2695 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2696 power operator and the result of math.pow(0.0, -2.0) will vary by
2697 platform. On Linux, it raises a ValueError.
2698
2699- A bug in Unicode string interpolation was fixed that occasionally
2700 caused errors with formats including "%%". For example, the
2701 following expression "%% %s" % u"abc" no longer raises a TypeError.
2702
2703- Compilation of deeply nested expressions raises MemoryError instead
2704 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2705
2706- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2707 rendering them useless. They are now written in binary mode again.
2708
2709Standard library
2710
2711- Keyword arguments are now accepted for most pattern and match object
2712 methods in SRE, the standard regular expression engine.
2713
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002714- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002715 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002716
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002717- Several bugs in the Unicode handling and error handling in _tkinter
2718 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002719
2720- Fix memory management errors in Merge() and Tkapp_Call() routines.
2721
2722- Several changes were made to cStringIO to make it compatible with
2723 the file-like object interface and with StringIO. If operations are
2724 performed on a closed object, an exception is raised. The truncate
2725 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002726 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002727
2728- There were many changes made to the linuxaudiodev module and its
2729 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002730 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002731
2732 Note that this module is named poorly, because it should work
2733 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002734 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002735
2736 The module now raises exceptions when errors occur instead of
2737 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2738 audio) and defines a getptr() method that calls the
2739 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2740
2741- The library_version attribute, introduced in an earlier beta, was
2742 removed because it can not be supported with early versions of the C
2743 readline library, which provides no way to determine the version at
2744 compile-time.
2745
2746- The binascii module is now enabled on Win64.
2747
Tim Peters46446d62000-10-09 21:19:31 +00002748- tokenize.py no longer suffers "recursion depth" errors when parsing
2749 programs with very long string literals.
2750
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002751Internals
2752
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002753- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002754 which is called when the interpreter starts up to determine where
2755 the standard library is installed. These vulnerabilities affect all
2756 previous versions of Python and can be exploited by setting very
2757 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2758 setuid Python script, although use of the wrapper in
2759 Misc/setuid-prog.c will eliminate the vulnerability.
2760
2761- Fixed garbage collection bugs in instance creation that were
2762 triggered when errors occurred during initialization. The solution,
2763 applied in cPickle and in PyInstance_New(), is to call
2764 PyObject_GC_Init() after the initialization of the object's
2765 container attributes is complete.
2766
2767- pyexpat adds definitions of PyModule_AddStringConstant and
2768 PyModule_AddObject if the Python version is less than 2.0, which
2769 provides compatibility with PyXML on Python 1.5.2.
2770
2771- If the platform has a bogus definition for LONG_BIT (the number of
2772 bits in a long), an error will be reported at compile time.
2773
2774- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2775 collection crashes and possibly other, unreported crashes.
2776
2777- Fixed a memory leak in _PyUnicode_Fini().
2778
2779Build issues
2780
2781- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002782 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002783 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002784
2785- The mmap.PAGESIZE constant is now initialized using sysconf when
2786 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2787
2788- The md5 file should now compile on all platforms.
2789
2790- The select module now compiles on platforms that do not define
2791 POLLRDNORM and related constants.
2792
2793- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002794 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002795
Jeremy Hylton10921202000-10-09 18:34:12 +00002796- BeOS: A number of changes were made to the build and installation
2797 process. ar-fake now operates on a directory of object files.
2798 dl_export.h is gone, and its macros now appear on the mwcc command
2799 line during build on PPC BeOS.
2800
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002801- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002802 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002803
2804- Cygwin: Support for shared libraries, Tkinter, and sockets.
2805
2806- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2807
2808Tools and other miscellany
2809
2810- Removed debugging prints from main used with freeze.
2811
Tim Peters46446d62000-10-09 21:19:31 +00002812- IDLE auto-indent no longer crashes when it encounters Unicode
2813 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002814
2815What's new in 2.0 beta 2 (since beta 1)?
2816========================================
2817
2818Core language, builtins, and interpreter
2819
Tim Peters482c0212000-09-26 06:33:09 +00002820- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002821 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002822
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002823- Add -h and -V command line options to print the usage message and
2824 Python version number and exit immediately.
2825
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002826- eval() and exec accept Unicode objects as code parameters.
2827
2828- getattr() and setattr() now also accept Unicode objects for the
2829 attribute name, which are converted to strings using the default
2830 encoding before lookup.
2831
2832- Multiplication on string and Unicode now does proper bounds
2833 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2834 string is too long."
2835
2836- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002837 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002838
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
2840Standard library and extensions
2841
Guido van Rossum5b08f132001-04-16 02:05:23 +00002842- socket module: the OpenSSL code now adds support for RAND_status()
2843 and EGD (Entropy Gathering Device).
2844
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002845- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002846 argument checking; it still takes no arguments.
2847
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002848- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002849
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002850- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002851
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002852- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002853
2854- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002855 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002856
2857- copy: Copy Unicode objects atomically.
2858
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002859- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002860
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002861- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002862
Fred Drake67233bc2000-09-26 16:40:27 +00002863- dbm: Add get() and setdefault() methods to dbm object. Add constant
2864 `library' to module that names the library used. Added doc strings
2865 and method names to error messages. Uses configure to determine
2866 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2867 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002868
2869- distutils: Update to version 0.9.3.
2870
2871- dl: Add several dl.RTLD_ constants.
2872
2873- fpectl: Now supported on FreeBSD.
2874
2875- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2876 found by the collector will be saved in gc.garbage. This is useful
2877 for debugging a program that creates reference cycles.
2878
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002879- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002880 of HTTP class. Do not close socket on zero-length response. Do not
2881 crash when server sends invalid content-length header.
2882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002883- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002884
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002885- marshal: When reading a short, sign-extend on platforms where shorts
2886 are bigger than 16 bits. When reading a long, repair the unportable
2887 sign extension that was being done for 64-bit machines. (It assumed
2888 that signed right shift sign-extends.)
2889
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002890- operator: Add contains(), invert(), __invert__() as aliases for
2891 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002892
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002893- os: Add support for popen2() and popen3() on all platforms where
2894 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002895
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002896- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002897 clicking on a file in Explorer (or passing the file name to the
2898 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002899
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002900- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002901 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902
2903- pickle: Now raises ValueError when an invalid pickle that contains
2904 a non-string repr where a string repr was expected. This behavior
2905 matches cPickle.
2906
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002907- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002908
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002909- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002910
2911- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002912 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002913 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002914
2915- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002916 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002917
2918- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002919 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002920 few cycles during startup since the first call to
2921 setdefaultencoding() will initialize the codec registry and the
2922 encodings package.
2923
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002924- socket: Support for size hint in readlines() method of object returned
2925 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002926
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002927- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002928 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002929 is followed by whitespace.
2930
Tim Petersa3a3a032000-11-30 05:22:44 +00002931- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002932
2933- struct: Check ranges for bytes and shorts.
2934
2935- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002936 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002937
2938- Tkinter: Image objects are now guaranteed to have unique ids. Set
2939 event.delta to zero if Tk version doesn't support mousewheel.
2940 Removed some debugging prints.
2941
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002942- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002943
Fred Drake67233bc2000-09-26 16:40:27 +00002944- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002945 which works around a bug in Norton AntiVirus 2000 that leads directly
2946 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002947
2948- xml: New version detection code allows PyXML to override standard
2949 XML package if PyXML version is greater than 0.6.1.
2950
Fred Drake64bb3802000-09-26 16:21:35 +00002951- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2952 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2953 tree only for nodes which are sufficiently interesting to a specific
2954 application. Does not provide the HTML-specific extensions. Still
2955 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002956
Fred Drake64bb3802000-09-26 16:21:35 +00002957- xml.sax: SAX 2 support for Python, including all the handler
2958 interfaces needed to process XML 1.0 compliant XML. Some
2959 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002960
Fred Drake64bb3802000-09-26 16:21:35 +00002961- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2962 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002963
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002964
Jeremy Hylton1b618592000-09-26 05:32:36 +00002965C API
2966
2967- Add three new convenience functions for module initialization --
2968 PyModule_AddObject(), PyModule_AddIntConstant(), and
2969 PyModule_AddStringConstant().
2970
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002971- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002972 removed and add #error to Python.h if NULL isn't defined after
2973 #include of stdio.h.
2974
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002975- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002976 backwards compatibility (at the source level) with old extensions.
2977
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002978- A wrapper API was added for signal() and sigaction(). Instead of
2979 either function, always use PyOS_getsig() to get a signal handler
2980 and PyOS_setsig() to set one. A new convenience typedef
2981 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002982
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002983- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002984 internal data buffer and size of a string object -- or the default
2985 encoded version of a Unicode object.
2986
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002987- PyString_Size() and PyString_AsString() accept Unicode objects.
2988
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002989- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002990 exists). INT_MAX and LONG_MAX will always be defined, even if
2991 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002992
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002993- PyFloat_FromString takes a second argument, pend, that was
2994 effectively useless. It is now officially useless but preserved for
2995 backwards compatibility. If the pend argument is not NULL, *pend is
2996 set to NULL.
2997
2998- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2999 for the attribute name. See note on getattr() above.
3000
3001- A few bug fixes to argument processing for Unicode.
3002 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3003 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3004 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003005 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003006
3007- Py_BuildValue accepts B format (for bgen-generated code).
3008
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003009
Jeremy Hylton1b618592000-09-26 05:32:36 +00003010Internals
3011
3012- On Unix, fix code for finding Python installation directory so that
3013 it works when argv[0] is a relative path.
3014
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003015- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003016 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003017 rather than by generating a copy of the object.
3018
Tim Peters482c0212000-09-26 06:33:09 +00003019- Several of the internal Unicode tables are much smaller now, and
3020 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003021
Jeremy Hylton97693b02000-09-26 17:42:51 +00003022- In the garbage collector: Fixed bug in collection of tuples. Fixed
3023 bug that caused some instances to be removed from the container set
3024 while they were still live. Fixed parsing in gc.set_debug() for
3025 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003026
3027- Fixed refcount problem in instance deallocation that only occurred
3028 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3029
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003030- On Windows, getpythonregpath is now protected against null data in
3031 registry key.
3032
3033- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003034 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003036
Jeremy Hylton1b618592000-09-26 05:32:36 +00003037Build and platform-specific issues
3038
3039- Better support of GNU Pth via --with-pth configure option.
3040
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003041- Python/C API now properly exposed to dynamically-loaded extension
3042 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003043
3044- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3045 Don't define MS_SYNC to be zero when it is undefined. Added missing
3046 prototypes in posixmodule.c.
3047
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003048- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003049 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003050
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003051- Fix largefile support on older NetBSD systems and OpenBSD by adding
3052 define for TELL64.
3053
3054
3055Tools and other miscellany
3056
3057- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3058
3059- freeze: The modulefinder now works with 2.0 opcodes.
3060
Tim Petersa3a3a032000-11-30 05:22:44 +00003061- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003062 Move hackery of sys.argv until after the Tk instance has been
3063 created, which allows the application-specific Tkinter
3064 initialization to be executed if present; also pass an explicit
3065 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003066
Jeremy Hylton1b618592000-09-26 05:32:36 +00003067
3068What's new in 2.0 beta 1?
3069=========================
3070
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003071Source Incompatibilities
3072------------------------
3073
3074None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3075such as single-argument append(), connect() and bind(), and changes to
3076str(long) and repr(float).
3077
3078
3079Binary Incompatibilities
3080------------------------
3081
3082- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3083with Python 2.0; these extensions will have to be rebuilt for Python
30842.0.
3085
3086- On Windows, attempting to import a third party extension built for
3087Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3088can do about this. Check your PYTHONPATH environment variable!
3089
3090- Python bytecode files (*.pyc and *.pyo) are not compatible between
3091releases.
3092
3093
3094Overview of Changes Since 1.6
3095-----------------------------
3096
3097There are many new modules (including brand new XML support through
3098the xml package, and i18n support through the gettext module); a list
3099of all new modules is included below. Lots of bugs have been fixed.
3100
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003101The process for making major new changes to the language has changed
3102since Python 1.6. Enhancements must now be documented by a Python
3103Enhancement Proposal (PEP) before they can be accepted.
3104
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003105There are several important syntax enhancements, described in more
3106detail below:
3107
3108 - Augmented assignment, e.g. x += 1
3109
3110 - List comprehensions, e.g. [x**2 for x in range(10)]
3111
3112 - Extended import statement, e.g. import Module as Name
3113
3114 - Extended print statement, e.g. print >> file, "Hello"
3115
3116Other important changes:
3117
3118 - Optional collection of cyclical garbage
3119
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003120Python Enhancement Proposal (PEP)
3121---------------------------------
3122
3123PEP stands for Python Enhancement Proposal. A PEP is a design
3124document providing information to the Python community, or describing
3125a new feature for Python. The PEP should provide a concise technical
3126specification of the feature and a rationale for the feature.
3127
3128We intend PEPs to be the primary mechanisms for proposing new
3129features, for collecting community input on an issue, and for
3130documenting the design decisions that have gone into Python. The PEP
3131author is responsible for building consensus within the community and
3132documenting dissenting opinions.
3133
3134The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003135
3136Augmented Assignment
3137--------------------
3138
3139This must have been the most-requested feature of the past years!
3140Eleven new assignment operators were added:
3141
Guido van Rossume905e952000-09-05 12:42:46 +00003142 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003143
3144For example,
3145
3146 A += B
3147
3148is similar to
3149
3150 A = A + B
3151
3152except that A is evaluated only once (relevant when A is something
3153like dict[index].attr).
3154
3155However, if A is a mutable object, A may be modified in place. Thus,
3156if A is a number or a string, A += B has the same effect as A = A+B
3157(except A is only evaluated once); but if a is a list, A += B has the
3158same effect as A.extend(B)!
3159
3160Classes and built-in object types can override the new operators in
3161order to implement the in-place behavior; the not-in-place behavior is
3162used automatically as a fallback when an object doesn't implement the
3163in-place behavior. For classes, the method name is derived from the
3164method name for the corresponding not-in-place operator by inserting
3165an 'i' in front of the name, e.g. __iadd__ implements in-place
3166__add__.
3167
3168Augmented assignment was implemented by Thomas Wouters.
3169
3170
3171List Comprehensions
3172-------------------
3173
3174This is a flexible new notation for lists whose elements are computed
3175from another list (or lists). The simplest form is:
3176
3177 [<expression> for <variable> in <sequence>]
3178
Guido van Rossum56db0952000-09-06 23:34:25 +00003179For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003180This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003181
3182You can also add a condition:
3183
3184 [<expression> for <variable> in <sequence> if <condition>]
3185
3186For example, [w for w in words if w == w.lower()] would yield the list
3187of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003188than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003189
3190You can also have nested for loops and more than one 'if' clause. For
3191example, here's a function that flattens a sequence of sequences::
3192
3193 def flatten(seq):
3194 return [x for subseq in seq for x in subseq]
3195
3196 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3197
3198This prints
3199
3200 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3201
3202List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003203Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003204
3205
3206Extended Import Statement
3207-------------------------
3208
3209Many people have asked for a way to import a module under a different
3210name. This can be accomplished like this:
3211
3212 import foo
3213 bar = foo
3214 del foo
3215
3216but this common idiom gets old quickly. A simple extension of the
3217import statement now allows this to be written as follows:
3218
3219 import foo as bar
3220
3221There's also a variant for 'from ... import':
3222
3223 from foo import bar as spam
3224
3225This also works with packages; e.g. you can write this:
3226
3227 import test.regrtest as regrtest
3228
3229Note that 'as' is not a new keyword -- it is recognized only in this
3230context (this is only possible because the syntax for the import
3231statement doesn't involve expressions).
3232
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003233Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003234
3235
3236Extended Print Statement
3237------------------------
3238
3239Easily the most controversial new feature, this extension to the print
3240statement adds an option to make the output go to a different file
3241than the default sys.stdout.
3242
3243For example, to write an error message to sys.stderr, you can now
3244write:
3245
3246 print >> sys.stderr, "Error: bad dog!"
3247
3248As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003249evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003250
3251 print >> None, "Hello world"
3252
3253is equivalent to
3254
3255 print "Hello world"
3256
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003257Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003258
3259
3260Optional Collection of Cyclical Garbage
3261---------------------------------------
3262
3263Python is now equipped with a garbage collector that can hunt down
3264cyclical references between Python objects. It's no replacement for
3265reference counting; in fact, it depends on the reference counts being
3266correct, and decides that a set of objects belong to a cycle if all
3267their reference counts can be accounted for from their references to
3268each other. This devious scheme was first proposed by Eric Tiedemann,
3269and brought to implementation by Neil Schemenauer.
3270
3271There's a module "gc" that lets you control some parameters of the
3272garbage collection. There's also an option to the configure script
3273that lets you enable or disable the garbage collection. In 2.0b1,
3274it's on by default, so that we (hopefully) can collect decent user
3275experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003276performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003277off by default in the final 2.0 release.
3278
3279
3280Smaller Changes
3281---------------
3282
3283A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3284map(None, seq1, seq2, ...) when the sequences have the same length;
3285i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3286the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003287zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003288
3289sys.version_info is a tuple (major, minor, micro, level, serial).
3290
3291Dictionaries have an odd new method, setdefault(key, default).
3292dict.setdefault(key, default) returns dict[key] if it exists; if not,
3293it sets dict[key] to default and returns that value. Thus:
3294
3295 dict.setdefault(key, []).append(item)
3296
3297does the same work as this common idiom:
3298
3299 if not dict.has_key(key):
3300 dict[key] = []
3301 dict[key].append(item)
3302
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003303There are two new variants of SyntaxError that are raised for
3304indentation-related errors: IndentationError and TabError.
3305
3306Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3307escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003308
3309The limits on the size of expressions and file in Python source code
3310have been raised from 2**16 to 2**32. Previous versions of Python
3311were limited because the maximum argument size the Python VM accepted
3312was 2**16. This limited the size of object constructor expressions,
3313e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3314limit was raised thanks to a patch by Charles Waldman that effectively
3315fixes the problem. It is now much more likely that you will be
3316limited by available memory than by an arbitrary limit in Python.
3317
3318The interpreter's maximum recursion depth can be modified by Python
3319programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3320limit is the maximum number of recursive calls that can be made by
3321Python code. The limit exists to prevent infinite recursion from
3322overflowing the C stack and causing a core dump. The default value is
33231000. The maximum safe value for a particular platform can be found
3324by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003325
3326New Modules and Packages
3327------------------------
3328
3329atexit - for registering functions to be called when Python exits.
3330
3331imputil - Greg Stein's alternative API for writing custom import
3332hooks.
3333
3334pyexpat - an interface to the Expat XML parser, contributed by Paul
3335Prescod.
3336
3337xml - a new package with XML support code organized (so far) in three
3338subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3339would fill a volume. There's a special feature whereby a
3340user-installed package named _xmlplus overrides the standard
3341xmlpackage; this is intended to give the XML SIG a hook to distribute
3342backwards-compatible updates to the standard xml package.
3343
3344webbrowser - a platform-independent API to launch a web browser.
3345
3346
Guido van Rossume905e952000-09-05 12:42:46 +00003347Changed Modules
3348---------------
3349
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003350array -- new methods for array objects: count, extend, index, pop, and
3351remove
3352
3353binascii -- new functions b2a_hex and a2b_hex that convert between
3354binary data and its hex representation
3355
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003356calendar -- Many new functions that support features including control
3357over which day of the week is the first day, returning strings instead
3358of printing them. Also new symbolic constants for days of week,
3359e.g. MONDAY, ..., SUNDAY.
3360
3361cgi -- FieldStorage objects have a getvalue method that works like a
3362dictionary's get method and returns the value attribute of the object.
3363
3364ConfigParser -- The parser object has new methods has_option,
3365remove_section, remove_option, set, and write. They allow the module
3366to be used for writing config files as well as reading them.
3367
3368ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003369optionally support the RFC 959 REST command.
3370
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003371gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003372
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003373httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3374the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003375
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003376locale -- implement getdefaultlocale for Win32 and Macintosh
3377
3378marshal -- no longer dumps core when marshaling deeply nested or
3379recursive data structures
3380
3381os -- new functions isatty, seteuid, setegid, setreuid, setregid
3382
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003383os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3384support under Unix.
3385
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003386os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003387
3388os.path -- fix semantics of os.path.commonprefix
3389
3390smtplib -- support for sending very long messages
3391
3392socket -- new function getfqdn()
3393
3394readline -- new functions to read, write and truncate history files.
3395The readline section of the library reference manual contains an
3396example.
3397
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003398select -- add interface to poll system call
3399
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003400shutil -- new copyfileobj function
3401
3402SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3403HTTP server.
3404
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003405Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003406
3407urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003408e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003409
3410whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003411
3412
3413Obsolete Modules
3414----------------
3415
3416None. However note that 1.6 made a whole slew of modules obsolete:
3417stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3418poly, zmod, strop, util, whatsound.
3419
3420
3421Changed, New, Obsolete Tools
3422----------------------------
3423
Tim Peters8b092332000-09-05 20:15:25 +00003424None.
Guido van Rossume905e952000-09-05 12:42:46 +00003425
3426
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003427C-level Changes
3428---------------
3429
3430Several cleanup jobs were carried out throughout the source code.
3431
3432All C code was converted to ANSI C; we got rid of all uses of the
3433Py_PROTO() macro, which makes the header files a lot more readable.
3434
3435Most of the portability hacks were moved to a new header file,
3436pyport.h; several other new header files were added and some old
3437header files were removed, in an attempt to create a more rational set
3438of header files. (Few of these ever need to be included explicitly;
3439they are all included by Python.h.)
3440
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003441Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003442and Win64, especially for the new Intel Itanium processor. Mick also
3443added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003444
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003445The C APIs to return an object's size have been update to consistently
3446use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3447previous versions, the abstract interfaces used PyXXX_Length and the
3448concrete interfaces used PyXXX_Size. The old names,
3449e.g. PyObject_Length, are still available for backwards compatibility
3450at the API level, but are deprecated.
3451
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003452The PyOS_CheckStack function has been implemented on Windows by
3453Fredrik Lundh. It prevents Python from failing with a stack overflow
3454on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003455
3456The GC changes resulted in creation of two new slots on object,
3457tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003458the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003459
3460The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003461C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003462
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003463PyErr_Format has been updated to automatically calculate the size of
3464the buffer needed to hold the formatted result string. This change
3465prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003466
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003467New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003468
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003469PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3470that are the same as their non-Ex counterparts except they take an
3471extra flag argument that tells them to close the file when done.
3472
3473XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003474
Tim Peters8b092332000-09-05 20:15:25 +00003475
3476Windows Changes
3477---------------
3478
3479New popen2/popen3/peopen4 in os module (see Changed Modules above).
3480
3481os.popen is much more usable on Windows 95 and 98. See Microsoft
3482Knowledge Base article Q150956. The Win9x workaround described there
3483is implemented by the new w9xpopen.exe helper in the root of your
3484Python installation. Note that Python uses this internally; it is not
3485a standalone program.
3486
3487Administrator privileges are no longer required to install Python
3488on Windows NT or Windows 2000. If you have administrator privileges,
3489Python's registry info will be written under HKEY_LOCAL_MACHINE.
3490Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003491under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003492uses of Python, but will prevent some advanced uses from working
3493(for example, running a Python script as an NT service, or possibly
3494from CGI).
3495
3496[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3497installer; instead, it installs the needed Tcl/Tk files directly in the
3498Python directory. If you already have a Tcl/Tk installation, this
3499wastes some disk space (about 4 Megs) but avoids problems with
3500conflicting Tcl/Tk installations, and makes it much easier for Python
3501to ensure that Tcl/Tk can find all its files.
3502
3503[This was new in 1.6] The Windows installer now installs by default in
3504\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3505
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003506
3507Updates to the changes between 1.5.2 and 1.6
3508--------------------------------------------
3509
3510The 1.6 NEWS file can't be changed after the release is done, so here
3511is some late-breaking news:
3512
3513New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3514and changes to getlocale() and setlocale().
3515
3516The new module is now enabled per default.
3517
3518It is not true that the encodings codecs cannot be used for normal
3519strings: the string.encode() (which is also present on 8-bit strings
3520!) allows using them for 8-bit strings too, e.g. to convert files from
3521cp1252 (Windows) to latin-1 or vice-versa.
3522
3523Japanese codecs are available from Tamito KAJIYAMA:
3524http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3525
3526
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003527======================================================================