blob: 803287e9e959630482cca5f8c1b5b649b4d94337 [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
Fred Draked0ba6362002-05-02 21:28:26 +00009- Deprecated features of xrange objects have been removed as
10 promised. The start, stop, and step attributes and the tolist()
11 method no longer exist. xrange repetition and slicing have been
12 removed.
13
Guido van Rossum7dab2422002-04-26 19:40:56 +000014- New builtin function enumerate(x), from PEP 279. Example:
15 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
16 The argument can be an arbitrary iterable object.
17
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000018- The assert statement no longer tests __debug__ at runtime. This means
19 that assert statements cannot be disabled by assigning a false value
20 to __debug__.
21
Walter Dörwald068325e2002-04-15 13:36:47 +000022- A method zfill() was added to str and unicode, that fills a numeric
23 string to the left with zeros. For example,
24 "+123".zfill(6) -> "+00123".
25
Guido van Rossum862fe3c2002-04-15 12:36:47 +000026- Complex numbers supported divmod() and the // and % operators, but
27 these make no sense. Since this was documented, they're being
28 deprecated now.
29
Guido van Rossum26dd8302002-04-26 20:11:29 +000030- String and unicode methods lstrip(), rstrip() and strip() now take
31 an optional argument that specifies the characters to strip. For
32 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000033
Guido van Rossumc69343b2002-04-12 19:22:48 +000034- Added a new dict method pop(key). This removes and returns the
35 value corresponding to key. [SF patch #539949]
36
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000037- Changed new-style class instantiation so that when C's __new__
38 method returns something that's not a C instance, its __init__ is
39 not called. [SF bug #537450]
40
Guido van Rossum181e41a2002-04-06 00:23:25 +000041- Fixed super() to work correctly with class methods. [SF bug #535444]
42
Guido van Rossum47834462002-04-04 15:21:33 +000043- A new built-in type, bool, has been added, as well as built-in
44 names for its two values, True and False. Comparisons and sundry
45 other operations that return a truth value have been changed to
46 return a bool instead. Read PEP 285 for an explanantion of why this
47 is backward compatible.
48
Guido van Rossum95b62a62002-03-29 01:07:24 +000049- Fixed two bugs reported as SF #535905: under certain conditions,
50 deallocating a deeply nested structure could cause a segfault in the
51 garbage collector, due to interaction with the "trashcan" code;
52 access to the current frame during destruction of a local variable
53 could access a pointer to freed memory.
54
Neil Schemenauer9d50d132002-03-22 17:06:59 +000055- The optional object allocator has been enabled by default.
56
Guido van Rossum8c842552002-03-14 23:05:54 +000057- If you try to pickle an instance of a class that has __slots__ but
58 doesn't define or override __getstate__, a TypeError is now raised.
59 This is done by adding a bozo __getstate__ to the class that always
60 raises TypeError. (Before, this would appear to be pickled, but the
61 state of the slots would be lost.)
62
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000063- PyErr_Display will provide file and line information for all exceptions
64 that have an attribute print_file_and_line, not just SyntaxErrors.
65
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000066- The UTF-8 codec will now encode and decode Unicode surrogates
67 correctly and without raising exceptions for unpaired ones.
68
Neal Norwitz649b7592002-01-01 19:07:13 +000069- file.xreadlines() now raises a ValueError if the file is closed:
70 Previously, an xreadlines object was returned which would raise
71 a ValueError when the xreadlines.next() method was called.
72
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000073- posix.killpg has been added where available.
74
Neal Norwitz0c766a02002-03-27 13:03:09 +000075- sys.exit() inadvertantly allowed more than one argument.
76 An exception will now be raised if more than one argument is used.
77
Tim Petersaf8446f2001-12-21 21:36:50 +000078Extension modules
79
Tim Peters81b92512002-04-29 01:37:32 +000080- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +000081 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +000082 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +000083
Martin v. Löwis06a83e92002-04-14 10:19:44 +000084- posix.mknod was added.
85
Martin v. Löwis2e64c342002-03-27 18:49:02 +000086- The locale module now exposes the C library's gettext interface.
87
Tim Petersfbf74f22002-03-14 19:06:01 +000088- A security hole ("double free") was found in zlib-1.1.3, a popular
89 third party compression library used by some Python modules. The
90 hole was quickly plugged in zlib-1.1.4, and the Windows build of
91 Python now ships with zlib-1.1.4.
92
Martin v. Löwis688357e2002-04-08 21:28:20 +000093- pwd, grp, and resource return enhanced tuples now, with symbolic
94 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000095
Martin v. Löwis99866332002-03-01 10:27:01 +000096- array.array is now a type object. A new format character
97 'u' indicates Py_UNICODE arrays. For those, .tounicode and
98 .fromunicode methods are available. Arrays now support __iadd__
99 and __imul__.
100
Neal Norwitze790eae2002-01-01 21:14:12 +0000101- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000102 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
103 is called.
104
Tim Petersaf8446f2001-12-21 21:36:50 +0000105Library
106
Tim Peters46c04e12002-05-05 20:40:00 +0000107- random.gauss() uses a piece of hidden state used by nothing else,
108 and the .seed() and .whseed() methods failed to reset it. In other
109 words, setting the seed didn't completely determine the sequence of
110 results produced by random.gauss(). It does now. Programs repeatedly
111 mixing calls to a seed method with calls to gauss() may see different
112 results now.
113
Fred Drake7f781c92002-05-01 20:33:53 +0000114- The pickle.Pickler class grew a clear_memo() method to mimic that
115 provided by cPickle.Pickler.
116
Tim Peters81b92512002-04-29 01:37:32 +0000117- difflib's SequenceMatcher class now does a dynamic analysis of
118 which elements are so frequent as to constitute noise. For
119 comparing files as sequences of lines, this generally works better
120 than the IS_LINE_JUNK function, and function ndiff's linejunk
121 argument defaults to None now as a result. A happy benefit is
122 that SequenceMatcher may run much faster now when applied
123 to large files with many duplicate lines (for example, C program
124 text with lots of repeated "}" and "return NULL;" lines).
125
Guido van Rossum256705b2002-04-23 13:29:43 +0000126- New Text.dump() method in Tkinter module.
127
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000128- New distutils commands for building packagers were added to
129 support pkgtool on Solaris and swinstall on HP-UX.
130
131- distutils now has a new abstract binary packager base class
132 command/bdist_packager, which simplifies writing packagers.
133 This will hopefully provide the missing bits to encourage
134 people to submit more packagers, e.g. for Debian, FreeBSD
135 and other systems.
136
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000137- The UTF-16, -LE and -BE now raise a NotImplementedError
138 for all calls to .readline(). Previously, they used to just
139 produce garbage or fail with an encoding error -- UTF-16 is
140 a 2-byte encoding and the C lib's line reading APIs don't
141 work well with these.
142
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000143- compileall now supports quiet operation.
144
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000145- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
146 connections.
147
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000148- socket module: the SSL support was broken out of the main
149 _socket module C helper and placed into a new _ssl helper
150 which now gets imported by socket.py if available and working.
151
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000152- encodings package: added aliases for all supported IANA character
153 sets
154
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000155- ftplib: to safeguard the user's privacy, anonymous login will use
156 "anonymous@" as default password, rather than the real user and host
157 name.
158
Fred Drake36736122002-01-10 13:50:31 +0000159- webbrowser: tightened up the command passed to os.system() so that
160 arbitrary shell code can't be executed because a bogus URL was
161 passed in.
162
Tim Peters11bd9942002-02-01 00:52:29 +0000163- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000164 gettext.find an optional all argument. Translations will now fallback
165 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000166
Martin v. Löwis9668b932002-01-12 11:27:42 +0000167- distutils bdist commands now offer a --skip-build option.
168
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000169- warnings.warn now accepts a Warning instance as first argument.
170
Fred Drakefed7e852002-04-04 19:36:15 +0000171- The xml.sax.expatreader.ExpatParser class will no longer create
172 circular references by using itself as the locator that gets passed
173 to the content handler implementation. [SF bug #535474]
174
Tim Petersaf8446f2001-12-21 21:36:50 +0000175Tools/Demos
176
Marc-André Lemburg46260092002-04-04 16:17:11 +0000177- freeze.py now produces binaries which can import shared modules,
178 unlike before when this failed due to missing symbol exports in
179 the generated binary.
180
Tim Petersaf8446f2001-12-21 21:36:50 +0000181Build
182
Tim Peters639295f2002-04-21 07:30:30 +0000183- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
184 say how or when to configure it, or how to turn it off.
185
Martin v. Löwis1142de32002-03-29 16:28:31 +0000186- On Unix, a shared libpython2.3.so can be created with --enable-shared.
187
Tim Peters8deda702002-03-30 10:06:07 +0000188- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
189 preprocessor symbols were eliminated. The internal decisions they
190 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000191
Fred Drake7d28b732002-05-02 21:17:00 +0000192- The tools used to build the documentation now work under Cygwin as
193 well as Unix.
194
Tim Petersaf8446f2001-12-21 21:36:50 +0000195C API
196
Fred Draked0ba6362002-05-02 21:28:26 +0000197- PyRange_New() now raises ValueError if the fourth argument is not 1.
198 This is part of the removal of deprecated features of the xrange
199 object.
200
Guido van Rossum517c7d42002-04-26 02:49:14 +0000201- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
202 coercion if both arguments have the same type but this type has the
203 CHECKTYPES flag set. This is to better support proxies.
204
Neil Schemenauer9344b142002-04-12 23:00:08 +0000205- The type of tp_free has been changed from "void (*)(PyObject *)" to
206 "void (*)(void *)".
207
208- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
209
Guido van Rossum0986d822002-04-08 01:38:42 +0000210- A type can now inherit its metatype from its base type. Previously,
211 when PyType_Ready() was called, if ob_type was found to be NULL, it
212 was always set to &PyType_Type; now it is set to base->ob_type,
213 where base is tp_base, defaulting to &PyObject_Type.
214
215- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
216
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000217- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
218 functions will be allocated using pymalloc if it is enabled. These
219 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
220 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
221 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
222 PyCore_* family of APIs have been removed.
223
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000224- The "u#" parser marker will now pass through Unicode object as-is
225 without going through the buffer API.
226
Martin v. Löwis7198a522002-01-01 19:59:11 +0000227- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
228
Tim Peters10a3bb52001-12-25 19:07:38 +0000229- An old #define of ANY as void has been removed from pyport.h. This
230 hasn't been used since Python's pre-ANSI days, and the #define has
231 been marked as obsolete since then. SF bug 495548 says it created
232 conflicts with other packages, so keeping it around wasn't harmless.
233
Tim Petersaf8446f2001-12-21 21:36:50 +0000234- Because Python's magic number scheme broke on January 1st, we decided
235 to stop Python development. Thanks for all the fish!
236
Tim Petersfb05db22002-03-11 00:24:00 +0000237- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000238 scheme to a new one. See Python/import.c for details.
239
Tim Petersaf8446f2001-12-21 21:36:50 +0000240New platforms
241
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000242- GNU/Hurd is now supported.
243
Tim Petersaf8446f2001-12-21 21:36:50 +0000244Tests
245
246Windows
247
Tim Peters08e72952002-04-16 20:48:01 +0000248- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
249 of that has been fixed in the installer (disabled Wise's "delete in-
250 use files" uninstall option).
251
Guido van Rossum181e41a2002-04-06 00:23:25 +0000252- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
253
Tim Peters33187922002-04-04 20:02:04 +0000254- The installer now installs Start menu shortcuts under (the local
255 equivalent of) "All Users" when doing an Admin install.
256
Tim Petersfb05db22002-03-11 00:24:00 +0000257- file.truncate([newsize]) now works on Windows for all newsize values.
258 It used to fail if newsize didn't fit in 32 bits, reflecting a
259 limitation of MS _chsize (which is no longer used).
260
Tim Petersab034fa2002-02-01 11:27:43 +0000261- os.waitpid() is now implemented for Windows, and can be used to block
262 until a specified process exits. This is similar to, but not exactly
263 the same as, os.waitpid() on POSIX systems. If you're waiting for
264 a specific process whose pid was obtained from one of the spawn()
265 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000266 See the docs for details. The docs were changed to clarify that
267 spawn functions return, and waitpid requires, a process handle on
268 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000269
Tim Peters11bd9942002-02-01 00:52:29 +0000270- New tempfile.TemporaryFile implementation for Windows: this doesn't
271 need a TemproraryFileWrapper wrapper anymore, and should be immune
272 to a nasty problem: before 2.3, if you got a temp file on Windows, it
273 got wrapped in an object whose close() method first closed the
274 underlying file, then deleted the file. This usually worked fine.
275 However, the spawn family of functions on Windows create (at a low C
276 level) the same set of open files in the spawned process Q as were
277 open in the spawning process P. If a temp file f was among them, then
278 doing f.close() in P first closed P's C-level file handle on f, but Q's
279 C-level file handle on f remained open, so the attempt in P to delete f
280 blew up with a "Permission denied" error (Windows doesn't allow
281 deleting open files). This was surprising, subtle, and difficult to
282 work around.
283
284- The os module now exports all the symbolic constants usable with the
285 low-level os.open() on Windows: the new constants in 2.3 are
286 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
287 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
288 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
289 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
290 (so specify both if you want both; note that neither is useful unless
291 specified with O_CREAT too).
292
Tim Petersaf8446f2001-12-21 21:36:50 +0000293Mac
294
295
Tim Peters909c0912001-12-14 23:16:18 +0000296What's New in Python 2.2 final?
297Release date: 21-Dec-2001
298===============================
299
300Type/class unification and new-style classes
301
Barry Warsaw52acb492001-12-21 20:04:22 +0000302- pickle.py, cPickle: allow pickling instances of new-style classes
303 with a custom metaclass.
304
Tim Peters909c0912001-12-14 23:16:18 +0000305Core and builtins
306
Barry Warsaw52acb492001-12-21 20:04:22 +0000307- weakref proxy object: when comparing, unwrap both arguments if both
308 are proxies.
309
Tim Peters909c0912001-12-14 23:16:18 +0000310Extension modules
311
Barry Warsaw52acb492001-12-21 20:04:22 +0000312- binascii.b2a_base64(): fix a potential buffer overrun when encoding
313 very short strings.
314
315- cPickle: the obscure "fast" mode was suspected of causing stack
316 overflows on the Mac. Hopefully fixed this by setting the recursion
317 limit much smaller. If the limit is too low (it only affects
318 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
319 when compiling cPickle.c (or in pyconfig.h).
320
Tim Peters909c0912001-12-14 23:16:18 +0000321Library
322
Barry Warsaw52acb492001-12-21 20:04:22 +0000323- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
324 close or delete time).
325
326- rfc822.py: fixed a bug where the address '<>' was converted to None
327 instead of an empty string (also fixes the email.Utils module).
328
329- xmlrpclib.py: version 1.0.0; uses precision for doubles.
330
331- test suite: the pickle and cPickle tests were not executing any code
332 when run from the standard regresssion test.
333
Tim Peters909c0912001-12-14 23:16:18 +0000334Tools/Demos
335
336Build
337
338C API
339
340New platforms
341
342Tests
343
344Windows
345
Barry Warsaw52acb492001-12-21 20:04:22 +0000346- distutils package: fixed broken Windows installers (bdist_wininst).
347
348- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
349 instances are deleted at process exit time.
350
351- socket.py: prevent mysterious warnings when socket instances are
352 deleted at process exit time.
353
354- posixmodule.c: fix a Windows crash with stat() of a filename ending
355 in backslash.
356
Tim Peters909c0912001-12-14 23:16:18 +0000357Mac
358
Barry Warsaw52acb492001-12-21 20:04:22 +0000359- The Carbon toolbox modules have been upgraded to Universal Headers
360 3.4, and experimental CoreGraphics and CarbonEvents modules have
361 been added. All only for framework-enabled MacOSX.
362
Tim Peters909c0912001-12-14 23:16:18 +0000363
Tim Peters6272dfd2001-12-13 19:34:00 +0000364What's New in Python 2.2c1?
365Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000366===========================
367
368Type/class unification and new-style classes
369
Barry Warsaw06557452001-12-14 20:47:12 +0000370- Guido's tutorial introduction to the new type/class features has
371 been extensively updated. See
372
373 http://www.python.org/2.2/descrintro.html
374
375 That remains the primary documentation in this area.
376
Guido van Rossum33bab012001-12-05 22:45:48 +0000377- Fixed a leak: instance variables declared with __slots__ were never
378 deleted!
379
Guido van Rossum4b800852001-12-03 00:54:52 +0000380- The "delete attribute" method of descriptor objects is called
381 __delete__, not __del__. In previous releases, it was mistakenly
382 called __del__, which created an unfortunate overloading condition
383 with finalizers. (The "get attribute" and "set attribute" methods
384 are still called __get__ and __set__, respectively.)
385
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000386- Some subtle issues with the super built-in were fixed:
387
388 (a) When super itself is subclassed, its __get__ method would still
389 return an instance of the base class (i.e., of super).
390
391 (b) super(C, C()).__class__ would return C rather than super. This
392 is confusing. To fix this, I decided to change the semantics of
393 super so that it only applies to code attributes, not to data
394 attributes. After all, overriding data attributes is not
395 supported anyway.
396
397 (c) The __get__ method didn't check whether the argument was an
398 instance of the type used in creation of the super instance.
399
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000400- Previously, hash() of an instance of a subclass of a mutable type
401 (list or dictionary) would return some value, rather than raising
402 TypeError. This has been fixed. Also, directly calling
403 dict.__hash__ and list.__hash__ now raises the same TypeError
404 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000405
Guido van Rossumd331cb52001-12-05 19:46:42 +0000406- New-style objects now support deleting their __dict__. This is for
407 all intents and purposes equivalent to assigning a brand new empty
408 dictionary, but saves space if the object is not used further.
409
Tim Petersb3c9af12001-11-17 00:21:57 +0000410Core and builtins
411
Tim Peters3caca232001-12-06 06:23:26 +0000412- -Qnew now works as documented in PEP 238: when -Qnew is passed on
413 the command line, all occurrences of "/" use true division instead
414 of classic division. See the PEP for details. Note that "all"
415 means all instances in library and 3rd-party modules, as well as in
416 your own code. As the PEP says, -Qnew is intended for use only in
417 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000418 Note that test_coercion.py in the standard Python test suite fails
419 under -Qnew; this is expected, and won't be repaired until true
420 division becomes the default (in the meantime, test_coercion is
421 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000422
Fred Drake6c01e252001-12-14 17:08:12 +0000423- complex() now only allows the first argument to be a string
424 argument, and raises TypeError if either the second arg is a string
425 or if the second arg is specified when the first is a string.
426
Tim Petersb3c9af12001-11-17 00:21:57 +0000427Extension modules
428
Martin v. Löwis560da622001-11-24 09:24:51 +0000429- gc.get_referents was renamed to gc.get_referrers.
430
Tim Petersb3c9af12001-11-17 00:21:57 +0000431Library
432
Tim Peters25059d32001-12-07 20:35:43 +0000433- Functions in the os.spawn() family now release the global interpreter
434 lock around calling the platform spawn. They should always have done
435 this, but did not before 2.2c1. Multithreaded programs calling
436 an os.spawn function with P_WAIT will no longer block all Python threads
437 until the spawned program completes. It's possible that some programs
438 relies on blocking, although more likely by accident than by design.
439
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000440- webbrowser defaults to netscape.exe on OS/2 now.
441
Martin v. Löwis652e1912001-11-25 14:50:56 +0000442- Tix.ResizeHandle exposes detach_widget, hide, and show.
443
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000444- The charset alias windows_1252 has been added.
445
Barry Warsaw06557452001-12-14 20:47:12 +0000446- types.StringTypes is a tuple containing the defined string types;
447 usually this will be (str, unicode), but if Python was compiled
448 without Unicode support it will be just (str,).
449
450- The pulldom and minidom modules were synchronized to PyXML.
451
Tim Petersb3c9af12001-11-17 00:21:57 +0000452Tools/Demos
453
Barry Warsaw06557452001-12-14 20:47:12 +0000454- A new script called Tools/scripts/google.py was added, which fires
455 off a search on Google.
456
Tim Petersb3c9af12001-11-17 00:21:57 +0000457Build
458
Barry Warsaw06557452001-12-14 20:47:12 +0000459- Note that release builds of Python should arrange to define the
460 preprocessor symbol NDEBUG on the command line (or equivalent).
461 In the 2.2 pre-release series we tried to define this by magic in
462 Python.h instead, but it proved to cause problems for extension
463 authors. The Unix, Windows and Mac builds now all define NDEBUG in
464 release builds via cmdline (or equivalent) instead. Ports to
465 other platforms should do likewise.
466
Jack Jansen1999ef42001-12-06 21:47:20 +0000467- It is no longer necessary to use --with-suffix when building on a
468 case-insensitive file system (such as Mac OS X HFS+). In the build
469 directory an extension is used, but not in the installed python.
470
Tim Petersb3c9af12001-11-17 00:21:57 +0000471C API
472
Tim Petersf582b822001-12-11 18:51:08 +0000473- New function PyDict_MergeFromSeq2() exposes the builtin dict
474 constructor's logic for updating a dictionary from an iterable object
475 producing key-value pairs.
476
Tim Peterscffed4b2001-11-29 03:26:37 +0000477- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000478 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000479 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
480 dump core in some bad cases. This has been repaired. As a result,
481 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
482 previously went unchallenged.
483
Tim Petersb3c9af12001-11-17 00:21:57 +0000484New platforms
485
486Tests
487
488Windows
489
490Mac
491
Jack Jansenffa260f2001-12-06 21:14:00 +0000492- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
493 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000494
Barry Warsaw06557452001-12-14 20:47:12 +0000495- Changed logic for finding python home in Mac OS X framework Pythons.
496 Now sys.executable points to the executable again, in stead of to
497 the shared library. The latter is used only for locating the python
498 home.
499
500
Tim Peters84362bc2001-10-19 17:55:30 +0000501What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000502Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000503===========================
504
505Type/class unification and new-style classes
506
Guido van Rossum3d27df02001-11-15 20:27:54 +0000507- Multiple inheritance mixing new-style and classic classes in the
508 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000509
510 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000511 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000512
513 The MRO (method resolution order) for each base class is respected
514 according to its kind, but the MRO for the derived class is computed
515 using new-style MRO rules if any base clase is a new-style class.
516 This needs to be documented.
517
Tim Petersa427a2b2001-10-29 22:25:45 +0000518- The new builtin dictionary() constructor, and dictionary type, have
519 been renamed to dict. This reflects a decade of common usage.
520
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000521- dict() now accepts an iterable object producing 2-sequences. For
522 example, dict(d.items()) == d for any dictionary d. The argument,
523 and the elements of the argument, can be any iterable objects.
524
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000525- New-style classes can now have a __del__ method, which is called
526 when the instance is deleted (just like for classic classes).
527
Guido van Rossum12d955c2001-10-26 14:56:06 +0000528- Assignment to object.__dict__ is now possible, for objects that are
529 instances of new-style classes that have a __dict__ (unless the base
530 class forbids it).
531
Guido van Rossumc8e56452001-10-22 00:43:43 +0000532- Methods of built-in types now properly check for keyword arguments
533 (formerly these were silently ignored). The only built-in methods
534 that take keyword arguments are __call__, __init__ and __new__.
535
Guido van Rossum86443212001-10-27 22:28:54 +0000536- The socket function has been converted to a type; see below.
537
Tim Peters84362bc2001-10-19 17:55:30 +0000538Core and builtins
539
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000540- Assignment to __debug__ raises SyntaxError at compile-time. This
541 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000542 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000543
Guido van Rossum12d955c2001-10-26 14:56:06 +0000544- Clarified the error messages for unsupported operands to an operator
545 (like 1 + '').
546
Tim Peters84362bc2001-10-19 17:55:30 +0000547Extension modules
548
Tim Peters5ebfd362001-11-13 23:11:19 +0000549- mmap has a new keyword argument, "access", allowing a uniform way for
550 both Windows and Unix users to create read-only, write-through and
551 copy-on-write memory mappings. This was previously possible only on
552 Unix. A new keyword argument was required to support this in a
553 uniform way because the mmap() signuatures had diverged across
554 platforms. Thanks to Jay T Miller for repairing this!
555
Tim Peters169ded02001-11-03 19:57:21 +0000556- By default, the gc.garbage list now contains only those instances in
557 unreachable cycles that have __del__ methods; in 2.1 it contained all
558 instances in unreachable cycles. "Instances" here has been generalized
559 to include instances of both new-style and old-style classes.
560
Guido van Rossum12d955c2001-10-26 14:56:06 +0000561- The socket module defines a new method for socket objects,
562 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000563 send() until all data has been sent. Also, the socket function has
564 been converted to a subclassable type, like list and tuple (etc.)
565 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000566
567- Various bugfixes to the curses module. There is now a test suite
568 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000569
Guido van Rossum692adf12001-10-30 03:03:03 +0000570- binascii.b2a_base64 no longer places an arbitrary restriction of 57
571 bytes on its input.
572
Tim Peters84362bc2001-10-19 17:55:30 +0000573Library
574
Tim Peters5ebfd362001-11-13 23:11:19 +0000575- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000576 convenience function.
577
Tim Peters75335872001-11-03 19:35:43 +0000578- Symbolic group names in regular expressions must be unique. For
579 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
580 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000581 Python 2.2 detects this error at regexp compilation time;
582 previously, the error went undetected, and results were
583 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
584 pattern.subn() methods have been rewritten in C. Also, an
585 experimental function/method finditer() has been added, which works
586 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000587
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000588- Tix exposes more commands through the classes DirSelectBox,
589 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
590 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
591 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
592
Tim Peters98791af2001-10-23 01:59:54 +0000593- Traceback objects are now scanned by cyclic garbage collection, so
594 cycles created by casual use of sys.exc_info() no longer cause
595 permanent memory leaks (provided garbage collection is enabled).
596
Guido van Rossum49192142001-10-24 20:51:44 +0000597- os.extsep -- a new variable needed by the RISCOS support. It is the
598 separator used by extensions, and is '.' on all platforms except
599 RISCOS, where it is '/'. There is no need to use this variable
600 unless you have a masochistic desire to port your code to RISCOS.
601
Barry Warsaw012852b2001-11-16 16:17:27 +0000602- mimetypes.py has optional support for non-standard, but commonly
603 found types. guess_type() and guess_extension() now accept an
604 optional `strict' flag, defaulting to true, which controls whether
605 recognize non-standard types or not. A few non-standard types we
606 know about have been added. Also, when run as a script, there are
607 new -l and -e options.
608
609- statcache is now deprecated.
610
611- email.Utils.formatdate() now produces the preferred RFC 2822 style
612 dates with numeric timezones (it used to produce obsolete dates
613 hard coded to "GMT" timezone). An optional `localtime' flag is
614 added to produce dates in the local timezone, with daylight savings
615 time properly taken into account.
616
617- In pickle and cPickle, instead of masking errors in load() by
618 transforming them into SystemError, we let the original exception
619 propagate out. Also, implement support for __safe_for_unpickling__
620 in pickle, as it already was supported in cPickle.
621
Tim Peters84362bc2001-10-19 17:55:30 +0000622Tools/Demos
623
624Build
625
Barry Warsaw012852b2001-11-16 16:17:27 +0000626- The dbm module is built using libdb1 if available. The bsddb module
627 is built with libdb3 if available.
628
629- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
630
Tim Peters84362bc2001-10-19 17:55:30 +0000631C API
632
Tim Peters1fc240e2001-10-26 05:06:50 +0000633- New function PySequence_Fast_GET_SIZE() returns the size of a non-
634 NULL result from PySequence_Fast(), more quickly than calling
635 PySequence_Size().
636
Barry Warsaw012852b2001-11-16 16:17:27 +0000637- New argument unpacking function PyArg_UnpackTuple() added.
638
639- New functions PyObject_CallFunctionObjArgs() and
640 PyObject_CallMethodObjArgs() have been added to make it more
641 convenient and efficient to call functions and methods from C.
642
643- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
644 possible that this will propagate errors it didn't before.
645
646- New function PyObject_CheckReadBuffer(), which returns true if its
647 argument supports the single-segment readable buffer interface.
648
Tim Peters84362bc2001-10-19 17:55:30 +0000649New platforms
650
Guido van Rossum86443212001-10-27 22:28:54 +0000651- We've finally confirmed that this release builds on HP-UX 11.00,
652 *with* threads, and passes the test suite.
653
Tim Peters7a33d8b2001-11-05 02:51:07 +0000654- Thanks to a series of patches from Michael Muller, Python may build
655 again under OS/2 Visual Age C++.
656
Guido van Rossum49192142001-10-24 20:51:44 +0000657- Updated RISCOS port by Dietmar Schwertberger.
658
Tim Peters84362bc2001-10-19 17:55:30 +0000659Tests
660
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000661- Added a test script for the curses module. It isn't run automatically;
662 regrtest.py must be run with '-u curses' to enable it.
663
Tim Peters84362bc2001-10-19 17:55:30 +0000664Windows
665
Barry Warsaw012852b2001-11-16 16:17:27 +0000666Mac
667
668- PythonScript has been moved to unsupported and is slated to be
669 removed completely in the next release.
670
671- It should now be possible to build applets that work on both OS9 and
672 OSX.
673
674- The core is now linked with CoreServices not Carbon; as a side
675 result, default 8bit encoding on OSX is now ASCII.
676
677- Python should now build on OSX 10.1.1
678
Tim Peters84362bc2001-10-19 17:55:30 +0000679
Tim Petersabf925f2001-09-28 21:53:42 +0000680What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000681Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000682===========================
683
684Type/class unification and new-style classes
685
Guido van Rossum687ae002001-10-15 22:03:32 +0000686- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000687 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000688 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000689 remains: the __dict__ of a new-style class is a read-only proxy; you
690 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000691 __defined__ attribute of new-style types no longer exists, for lack
692 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000693 future a __cache__ may be resurrected with a similar function, if I
694 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000695
Tim Peters1c9ca872001-10-04 06:43:12 +0000696- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
697 always returned None, even when there was a class docstring).
698
699- doctest now finds and runs docstrings attached to new-style classes,
700 class methods, static methods, and properties.
701
Guido van Rossum9074ef62001-10-16 21:34:49 +0000702Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000703
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000704- A very subtle syntactical pitfall in list comprehensions was fixed.
705 For example: [a+b for a in 'abc', for b in 'def']. The comma in
706 this example is a mistake. Previously, this would silently let 'a'
707 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
708 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
709 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
710 Note that [a for a in <singleton>] is a convoluted way to say
711 [<singleton>] anyway, so it's not like any expressiveness is lost.
712
Guido van Rossum9074ef62001-10-16 21:34:49 +0000713- getattr(obj, name, default) now only catches AttributeError, as
714 documented, rather than returning the default value for all
715 exceptions (which could mask bugs in a __getattr__ hook, for
716 example).
717
Fred Drakecb7a6b52001-10-22 18:41:51 +0000718- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000719 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000720 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000721 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000722
Guido van Rossum1c486092001-10-19 02:05:35 +0000723- unicode(obj) now behaves more like str(obj), accepting arbitrary
724 objects, and calling a __unicode__ method if it exists.
725 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000726 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000727
Barry Warsawf6fb1712001-10-19 05:35:40 +0000728- isinstance() now allows any object as the first argument and a
729 class, a type or something with a __bases__ tuple attribute for the
730 second argument. The second argument may also be a tuple of a
731 class, type, or something with __bases__, in which case isinstance()
732 will return true if the first argument is an instance of any of the
733 things contained in the second argument tuple. E.g.
734
735 isinstance(x, (A, B))
736
737 returns true if x is an instance of A or B.
738
Guido van Rossum9074ef62001-10-16 21:34:49 +0000739Extension modules
740
741- thread.start_new_thread() now returns the thread ID (previously None).
742
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000743- binascii has now two quopri support functions, a2b_qp and b2a_qp.
744
Guido van Rossumc524d952001-10-19 01:31:59 +0000745- readline now supports setting the startup_hook and the
746 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000747
Guido van Rossumc524d952001-10-19 01:31:59 +0000748- os and posix supports chroot(), setgroups() and unsetenv() where
749 available. The stat(), fstat(), statvfs() and fstatvfs() functions
750 now return "pseudo-sequences" -- the various fields can now be
751 accessed as attributes (e.g. os.stat("/").st_mtime) but for
752 backwards compatibility they also behave as a fixed-length sequence.
753 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000754 attributes.
755
756- time: localtime(), gmtime() and strptime() now return a
757 pseudo-sequence similar to the os.stat() return value, with
758 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000759
Guido van Rossum9074ef62001-10-16 21:34:49 +0000760- Decompression objects in the zlib module now accept an optional
761 second parameter to decompress() that specifies the maximum amount
762 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000763
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000764- optional SSL support in the socket module now exports OpenSSL
765 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
766 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000767 automatically seed its PRNG. Also, the keyfile and certfile
768 arguments to socket.ssl() are now optional.
769
770- posixmodule (and by extension, the os module on POSIX platforms) now
771 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000772
Guido van Rossum9074ef62001-10-16 21:34:49 +0000773Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000774
Tim Peters7402f792001-10-02 03:53:41 +0000775- doctest now excludes functions and classes not defined by the module
776 being tested, thanks to Tim Hochberg.
777
Fred Drakecb7a6b52001-10-22 18:41:51 +0000778- HotShot, a new profiler implemented using a C-based callback, has
779 been added. This substantially reduces the overhead of profiling,
780 but it is still quite preliminary. Support modules and
781 documentation will be added in upcoming releases (before 2.2 final).
782
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000783- profile now produces correct output in situations where an exception
784 raised in Python is cleared by C code (e.g. hasattr()). This used
785 to cause wrong output, including spurious claims of recursive
786 functions and attribution of time spent to the wrong function.
787
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000788 The code and documentation for the derived OldProfile and HotProfile
789 profiling classes was removed. The code hasn't worked for years (if
790 you tried to use them, they raised exceptions). OldProfile
791 intended to reproduce the behavior of the profiler Python used more
792 than 7 years ago, and isn't interesting anymore. HotProfile intended
793 to provide a faster profiler (but producing less information), and
794 that's a worthy goal we intend to meet via a different approach (but
795 without losing information).
796
Tim Peterscce092d2001-10-09 05:31:56 +0000797- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000798 a much better system-specific calibration constant. The constant can
799 now be specified in an instance constructor, or as a Profile class or
800 instance variable, instead of by editing profile.py's source code.
801 Calibration must still be done manually (see the docs for the profile
802 module).
803
804 Note that Profile.calibrate() must be overriden by subclasses.
805 Improving the accuracy required exploiting detailed knowledge of
806 profiler internals; the earlier method abstracted away the details
807 and measured a simplified model instead, but consequently computed
808 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000809
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000810- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000811 which indicates whether output is intended for the header 'Q'
812 encoding.
813
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000814- The SocketServer.ThreadingMixIn class now closes the request after
815 finish_request() returns. (Not when it errors out though.)
816
Barry Warsawf6fb1712001-10-19 05:35:40 +0000817- The nntplib module's NNTP.body() method has grown a `file' argument
818 to allow saving the message body to a file.
819
820- The email package has added a class email.Parser.HeaderParser which
821 only parses headers and does not recurse into the message's body.
822 Also, the module/class MIMEAudio has been added for representing
823 audio data (contributed by Anthony Baxter).
824
825- ftplib should be able to handle files > 2GB.
826
827- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
828 ON, and OFF.
829
Fred Drakecb7a6b52001-10-22 18:41:51 +0000830- xml.dom.minidom NodeList objects now support the length attribute
831 and item() method as required by the DOM specifications.
832
Guido van Rossumed554f62001-10-02 23:15:37 +0000833Tools/Demos
834
835- Demo/dns was removed. It no longer serves any purpose; a package
836 derived from it is now maintained by Anthony Baxter, see
837 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000838
Barry Warsawf6fb1712001-10-19 05:35:40 +0000839- The freeze tool has been made more robust, and two new options have
840 been added: -X and -E.
841
Tim Petersabf925f2001-09-28 21:53:42 +0000842Build
843
Barry Warsawf6fb1712001-10-19 05:35:40 +0000844- configure will use CXX in LINKCC if CXX is used to build main() and
845 the system requires to link a C++ main using the C++ compiler.
846
Tim Petersabf925f2001-09-28 21:53:42 +0000847C API
848
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000849- The documentation for the tp_compare slot is updated to require that
850 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
851 not correct. This is not yet enforced but will be enforced in
852 Python 2.3; even later, we may use -2 to indicate errors and +2 for
853 "NotImplemented". Right now, -1 should be used for an error return.
854
Tim Petersd38b1c72001-09-30 05:09:37 +0000855- PyLong_AsLongLong() now accepts int (as well as long) arguments.
856 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
857 as long) arguments.
858
Guido van Rossum3c288632001-10-16 21:13:49 +0000859- PyThread_start_new_thread() now returns a long int giving the thread
860 ID, if one can be calculated; it returns -1 for error, 0 if no
861 thread ID is calculated (this is an incompatible change, but only
862 the thread module used this API). This code has only really been
863 tested on Linux and Windows; other platforms please beware (and
864 report any bugs or strange behavior).
865
Guido van Rossum1c486092001-10-19 02:05:35 +0000866- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
867 input.
868
Tim Petersabf925f2001-09-28 21:53:42 +0000869New platforms
870
871Tests
872
873Windows
874
Tim Peters04cf1d32001-10-09 22:39:40 +0000875- Installer: If you install IDLE, and don't disable file-extension
876 registration, a new "Edit with IDLE" context (right-click) menu entry
877 is created for .py and .pyw files.
878
Tim Peters1ce3cf72001-10-01 17:58:40 +0000879- The signal module now supports SIGBREAK on Windows, thanks to Steven
880 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
881 action remains to call Win32 ExitProcess(). This can be changed via
882 signal.signal(). For example:
883
884 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
885 # (SIGINT) behavior.
886 import signal
887 signal.signal(signal.SIGBREAK,
888 signal.default_int_handler)
889
890 try:
891 while 1:
892 pass
893 except KeyboardInterrupt:
894 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
895 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
896 # program without the possibility for any Python-level cleanup).
897 print "Clean exit"
898
Tim Petersabf925f2001-09-28 21:53:42 +0000899
Tim Petersb07352e2001-09-08 01:25:47 +0000900What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000901Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000902===========================
903
Guido van Rossum808eea72001-09-25 04:15:41 +0000904Type/class unification and new-style classes
905
906- pydoc and inspect are now aware of new-style classes;
907 e.g. help(list) at the interactive prompt now shows proper
908 documentation for all operations on list objects.
909
910- Applications using Jim Fulton's ExtensionClass module can now safely
911 be used with Python 2.2. In particular, Zope 2.4.1 now works with
912 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
913 examples also work again. It is hoped that Gtk and Boost also work
914 with 2.2a4 and beyond. (If you can confirm this, please write
915 webmaster@python.org; if there are still problems, please open a bug
916 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000917
Tim Peters66c1a522001-09-24 21:17:50 +0000918- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
919 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
920 in the constructed property object. fget, fset and fdel weren't
921 discoverable from Python in 2.2a3. __doc__ is new, and allows to
922 associate a docstring with a property.
923
Guido van Rossum808eea72001-09-25 04:15:41 +0000924- Comparison overloading is now more completely implemented. For
925 example, a str subclass instance can properly be compared to a str
926 instance, and it can properly overload comparison. Ditto for most
927 other built-in object types.
928
929- The repr() of new-style classes has changed; instead of <type
930 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
931 *except* for built-in types, which are still rendered as <type
932 'Foo'> (to avoid upsetting existing code that might parse or
933 otherwise rely on repr() of certain type objects).
934
935- The repr() of new-style objects is now always <Foo object at XXX>;
936 previously, it was sometimes <Foo instance at XXX>.
937
938- For new-style classes, what was previously called __getattr__ is now
939 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000940 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000941 one in classic classes is defined which is called only if regular
942 attribute access raises AttributeError; to catch *all* attribute
943 access, you can use __getattribute__ (for new-style classes). If
944 both are defined, __getattribute__ is called first, and if it raises
945 AttributeError, __getattr__ is called.
946
947- The __class__ attribute of new-style objects can be assigned to.
948 The new class must have the same C-level object layout as the old
949 class.
950
951- The builtin file type can be subclassed now. In the usual pattern,
952 "file" is the name of the builtin type, and file() is a new builtin
953 constructor, with the same signature as the builtin open() function.
954 file() is now the preferred way to open a file.
955
956- Previously, __new__ would only see sequential arguments passed to
957 the type in a constructor call; __init__ would see both sequential
958 and keyword arguments. This made no sense whatsoever any more, so
959 now both __new__ and __init__ see all arguments.
960
961- Previously, hash() applied to an instance of a subclass of str or
962 unicode always returned 0. This has been repaired.
963
964- Previously, an operation on an instance of a subclass of an
965 immutable type (int, long, float, complex, tuple, str, unicode),
966 where the subtype didn't override the operation (and so the
967 operation was handled by the builtin type), could return that
968 instance instead a value of the base type. For example, if s was of
969 a str sublass type, s[:] returned s as-is. Now it returns a str
970 with the same value as s.
971
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000972- Provisional support for pickling new-style objects has been added.
973
Guido van Rossum808eea72001-09-25 04:15:41 +0000974Core
975
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000976- file.writelines() now accepts any iterable object producing strings.
977
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000978- PyUnicode_FromEncodedObject() now works very much like
979 PyObject_Str(obj) in that it tries to use __str__/tp_str
980 on the object if the object is not a string or buffer. This
981 makes unicode() behave like str() when applied to non-string/buffer
982 objects.
983
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000984- PyFile_WriteObject now passes Unicode objects to the file's write
985 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000986 of a print statement must support Unicode objects, i.e. they must
987 at least convert them into ASCII strings.
988
Guido van Rossum624c8af2001-09-18 15:21:04 +0000989- Thread scheduling on Solaris should be improved; it is no longer
990 necessary to insert a small sleep at the start of a thread in order
991 to let other runnable threads be scheduled.
992
Tim Petersb07352e2001-09-08 01:25:47 +0000993Library
994
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000995- StringIO.StringIO instances and cStringIO.StringIO instances support
996 read character buffer compatible objects for their .write() methods.
997 These objects are converted to strings and then handled as such
998 by the instances.
999
Barry Warsaw2f600732001-09-24 04:28:10 +00001000- The "email" package has been added. This is basically a port of the
1001 mimelib package <http://sf.net/projects/mimelib> with API changes
1002 and some implementations updated to use iterators and generators.
1003
Tim Peters8a9c2842001-09-22 21:30:22 +00001004- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1005 restores the ability of Tools/scripts/ndiff.py to start producing output
1006 before the entire comparison is complete.
1007
Barry Warsaw58b072d2001-09-22 04:44:21 +00001008- StringIO.StringIO instances and cStringIO.StringIO instances support
1009 iteration just like file objects (i.e. their .readline() method is
1010 called for each iteration until it returns an empty string).
1011
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001012- The codecs module has grown four new helper APIs to access
1013 builtin codecs: getencoder(), getdecoder(), getreader(),
1014 getwriter().
1015
Guido van Rossum624c8af2001-09-18 15:21:04 +00001016- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1017 simplifies writing XML RPC servers.
1018
Barry Warsaw647d5e82001-09-28 17:01:02 +00001019- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001020 after interpretation of symbolic links. On non-Unix systems, this
1021 is an alias for os.path.abspath().
1022
Tim Peters16a77ad2001-09-08 04:00:12 +00001023- operator.indexOf() (PySequence_Index() in the C API) now works with any
1024 iterable object.
1025
Guido van Rossum624c8af2001-09-18 15:21:04 +00001026- smtplib now supports various authentication and security features of
1027 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001028
Guido van Rossum624c8af2001-09-18 15:21:04 +00001029- hmac: a new module implementing keyed hashing for message
1030 authentication.
1031
1032- mimetypes now recognizes more extensions and file types. At the
1033 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001034
Guido van Rossum624c8af2001-09-18 15:21:04 +00001035- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001036 Python 2.2 bytecode generation. It has also been promoted from a
1037 Tool to a standard library package. (Tools/compiler still exists as
1038 a sample driver.)
1039
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001040Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001041
Tim Petersb07352e2001-09-08 01:25:47 +00001042Build
1043
Guido van Rossum624c8af2001-09-18 15:21:04 +00001044- Large file support (LFS) is now automatic when the platform supports
1045 it; no more manual configuration tweaks are needed. On Linux, at
1046 least, it's possible to have a system whose C library supports large
1047 files but whose kernel doesn't; in this case, large file support is
1048 still enabled but doesn't do you any good unless you upgrade your
1049 kernel or share your Python executable with another system whose
1050 kernel has large file support.
1051
1052- The configure script now supplies plausible defaults in a
1053 cross-compilation environment. This doesn't mean that the supplied
1054 values are always correct, or that cross-compilation now works
1055 flawlessly -- but it's a first step (and it shuts up most of
1056 autoconf's warnings about AC_TRY_RUN).
1057
1058- The Unix build is now a bit less chatty, courtesy of the parser
1059 generator. The build is completely silent (except for errors) when
1060 using "make -s", thanks to a -q option to setup.py.
1061
Tim Petersb07352e2001-09-08 01:25:47 +00001062C API
1063
Guido van Rossum624c8af2001-09-18 15:21:04 +00001064- The "structmember" API now supports some new flag bits to deny read
1065 and/or write access to attributes in restricted execution mode.
1066
Tim Petersb07352e2001-09-08 01:25:47 +00001067New platforms
1068
Guido van Rossum624c8af2001-09-18 15:21:04 +00001069- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1070 (http://familiar.handhelds.org).
1071
Tim Petersb07352e2001-09-08 01:25:47 +00001072Tests
1073
Tim Peters8a9c2842001-09-22 21:30:22 +00001074- The "classic" standard tests, which work by comparing stdout to
1075 an expected-output file under Lib/test/output/, no longer stop at
1076 the first mismatch. Instead the test is run to completion, and a
1077 variant of ndiff-style comparison is used to report all differences.
1078 This is much easier to understand than the previous style of reporting.
1079
1080- The unittest-based standard tests now use regrtest's test_main()
1081 convention, instead of running as a side-effect of merely being
1082 imported. This allows these tests to be run in more natural and
1083 flexible ways as unittests, outside the regrtest framework.
1084
1085- regrtest.py is much better integrated with unittest and doctest now,
1086 especially in regard to reporting errors.
1087
Tim Petersb07352e2001-09-08 01:25:47 +00001088Windows
1089
Guido van Rossum624c8af2001-09-18 15:21:04 +00001090- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001091 that support it (NTFS under Windows 2000). See "What's New in
1092 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001093
Tim Petersb07352e2001-09-08 01:25:47 +00001094
Tim Petersedc99312001-08-22 21:36:50 +00001095What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001096Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001097===========================
1098
1099Core
1100
Tim Peters9fffa3e2001-09-04 05:14:19 +00001101- Conversion of long to float now raises OverflowError if the long is too
1102 big to represent as a C double.
1103
Tim Peters32f453e2001-09-03 08:35:41 +00001104- The 3-argument builtin pow() no longer allows a third non-None argument
1105 if either of the first two arguments is a float, or if both are of
1106 integer types and the second argument is negative (in which latter case
1107 the arguments are converted to float, so this is really the same
1108 restriction).
1109
Tim Peters5d2b77c2001-09-03 05:47:38 +00001110- The builtin dir() now returns more information, and sometimes much
1111 more, generally naming all attributes of an object, and all attributes
1112 reachable from the object via its class, and from its class's base
1113 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1114 an empty list. In 2.2a3,
1115
1116 >>> dir([])
1117 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1118 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1119 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1120 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1121 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1122 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1123 'reverse', 'sort']
1124
1125 dir(module) continues to return only the module's attributes, though.
1126
Tim Petersbdee63f2001-09-02 03:40:59 +00001127- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001128 than raising OverflowError. This is a partial implementation of PEP
1129 237. You can use -Wdefault::OverflowWarning to enable a warning for
1130 this situation, and -Werror::OverflowWarning to revert to the old
1131 OverflowError exception.
1132
Guido van Rossum61c345f2001-09-04 03:26:15 +00001133- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001134 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001135 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1136 -Qold, meaning the / operator has its classic meaning and no
1137 warnings are issued. Using -Qwarn issues a run-time warning about
1138 all uses of classic division for int and long arguments; -Qwarnall
1139 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001140 (for use with fixdiv.py).
1141 [Note: the remainder of this paragraph (preserved below) became
1142 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1143 <obsolete>
1144 Using -Qnew is questionable; it turns on new division by default, but
1145 only in the __main__ module. You can usefully combine -Qwarn or
1146 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1147 warns about classic division everywhere else.
1148 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001149
Tim Petersbdee63f2001-09-02 03:40:59 +00001150- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001151 long, float, str, unicode, and tuple. (The types complex, list and
1152 dictionary can also be subclassed; this was introduced earlier.)
1153 Note that restrictions apply when subclassing immutable built-in
1154 types: you can only affect the value of the instance by overloading
1155 __new__. You can add mutable attributes, and the subclass instances
1156 will have a __dict__ attribute, but you cannot change the "value"
1157 (as implemented by the base class) of an immutable subclass instance
1158 once it is created.
1159
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001160- The dictionary constructor now takes an optional argument, a
1161 mapping-like object, and initializes the dictionary from its
1162 (key, value) pairs.
1163
Tim Petersbdee63f2001-09-02 03:40:59 +00001164- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001165 "cooperative super calls" in a multiple inheritance setting. For an
1166 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1167
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001168- A new built-in type, property, has been added. This enables the
1169 creation of "properties". These are attributes implemented by
1170 getter and setter functions (or only one of these for read-only or
1171 write-only attributes), without the need to override __getattr__.
1172 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001173
Tim Petersbdee63f2001-09-02 03:40:59 +00001174- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001175 liberalized, to allow leading zeroes. Examples of literals now
1176 legal that were SyntaxErrors before:
1177
1178 00.0 0e3 0100j 07.5 00000000000000000008.
1179
Tim Petersbdee63f2001-09-02 03:40:59 +00001180- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001181 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1182
Tim Petersedc99312001-08-22 21:36:50 +00001183Library
1184
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001185- telnetlib includes symbolic names for the options, and support for
1186 setting an option negotiation callback.
1187
Tim Petersa40c7932001-09-05 22:36:56 +00001188- The new C standard no longer requires that math libraries set errno to
1189 ERANGE on overflow. For platform libraries that exploit this new
1190 freedom, Python's overflow-checking was wholly broken. A new overflow-
1191 checking scheme attempts to repair that, but may not be reliable on all
1192 platforms (C doesn't seem to provide anything both useful and portable
1193 in this area anymore).
1194
Martin v. Löwis44f86962001-09-05 13:44:54 +00001195- Asynchronous timeout actions are available through the new class
1196 threading.Timer.
1197
Tim Peters78526162001-09-05 00:53:45 +00001198- math.log and math.log10 now return sensible results for even huge
1199 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1200
Tim Petersbdee63f2001-09-02 03:40:59 +00001201- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001202 currently held. See the docs for the imp module.
1203
Tim Petersbdee63f2001-09-02 03:40:59 +00001204- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001205 dumps containing ints written on platforms where Python ints are 8 bytes.
1206 When read on a box where Python ints are 4 bytes, such values are
1207 converted to Python longs.
1208
Tim Petersbdee63f2001-09-02 03:40:59 +00001209- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001210 code objects is no longer allowed. This plugs a security hole.
1211
Steve Purcell6091cd62001-09-06 16:05:17 +00001212- unittest.TestResult instances no longer store references to tracebacks
1213 generated by test failures. This prevents unexpected dangling references
1214 to objects that should be garbage collected between tests.
1215
Tim Petersedc99312001-08-22 21:36:50 +00001216Tools
1217
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001218- Tools/scripts/fixdiv.py has been added which can be used to fix
1219 division operators as per PEP 238.
1220
Tim Petersedc99312001-08-22 21:36:50 +00001221Build
1222
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001223- If you are an adventurous person using Mac OS X you may want to look at
1224 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1225 application, which can be used for experimenting with Carbon or Cocoa.
1226 Discussion of this on pythonmac-sig, please.
1227
Tim Peters7eea37e2001-09-04 22:08:56 +00001228C API
1229
1230- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001231
Tim Peters9fffa3e2001-09-04 05:14:19 +00001232- Note that PyLong_AsDouble can fail! This has always been true, but no
1233 callers checked for it. It's more likely to fail now, because overflow
1234 errors are properly detected now. The proper way to check:
1235
1236 double x = PyLong_AsDouble(some_long_object);
1237 if (x == -1.0 && PyErr_Occurred()) {
1238 /* The conversion failed. */
1239 }
1240
Tim Petersbdee63f2001-09-02 03:40:59 +00001241- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001242 compile but will not participate in GC. To upgrade an extension
1243 module:
1244
1245 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001246
Neil Schemenauer4042c692001-08-30 15:38:01 +00001247 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1248 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001249
Neil Schemenauer4042c692001-08-30 15:38:01 +00001250 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1251 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001252
Neil Schemenauer4042c692001-08-30 15:38:01 +00001253 - remove PyGC_HEAD_SIZE from object size calculations
1254
1255 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1256
Tim Petersbdee63f2001-09-02 03:40:59 +00001257- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001258 These can be used safely to construct string objects from a
1259 sprintf-style format string (similar to the format string supported
1260 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001261
Tim Petersedc99312001-08-22 21:36:50 +00001262New platforms
1263
Tim Petersb7da0902001-09-02 23:01:43 +00001264- Stephen Hansen contributed patches sufficient to get a clean compile
1265 under Borland C (Windows), but he reports problems running it and ran
1266 out of time to complete the port. Volunteers? Expect a MemoryError
1267 when importing the types module; this is probably shallow, and
1268 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001269
Tim Petersedc99312001-08-22 21:36:50 +00001270Tests
1271
1272Windows
1273
Tim Peters6e13a562001-09-06 00:32:15 +00001274- Large file support is now enabled on Win32 platforms as well as on
1275 Win64. This means that, for example, you can use f.tell() and f.seek()
1276 to manipulate files larger than 2 gigabytes (provided you have enough
1277 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001278 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1279 filesize limit, and large file support makes no difference there.
1280 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1281 NTFS has no practical limit on file size, and files of any size can be
1282 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001283
Tim Petersbdee63f2001-09-02 03:40:59 +00001284- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001285 points to command.com (patch from Brian Quinlan).
1286
Tim Petersedc99312001-08-22 21:36:50 +00001287
Tim Peters20f51a72001-07-21 02:31:40 +00001288What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001289Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001290===========================
1291
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001292Build
1293
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001294- Tim Peters developed a brand new Windows installer using Wise 8.1,
1295 generously donated to us by Wise Solutions.
1296
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001297- configure supports a new option --enable-unicode, with the values
1298 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1299 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001300
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001301- A new configure option --enable-framework builds a Mac OS X framework,
1302 which "make frameworkinstall" will install. This provides a starting
1303 point for more mac-like functionality, join pythonmac-sig@python.org
1304 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001305
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001306- The NeXT platform is no longer supported.
1307
1308- The `new' module is now statically linked.
1309
Tim Peters0afb6092001-08-15 06:06:44 +00001310Tools
1311
1312- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001313 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001314 the module docstring for details.
1315
Tim Peters20f51a72001-07-21 02:31:40 +00001316Tests
1317
Tim Peters5e824c32001-08-12 22:25:01 +00001318- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001319 platforms, allowing to give clearer test result output. regrtest
1320 also has optional --use/-u switch to run normally disabled tests
1321 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001322
Tim Peters20f51a72001-07-21 02:31:40 +00001323- Several new tests in the standard test suite, with special thanks to
1324 Nick Mathewson.
1325
1326Core
1327
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001328- The floor division operator // has been added as outlined in PEP
1329 238. The / operator still provides classic division (and will until
1330 Python 3.0) unless "from __future__ import division" is included, in
1331 which case the / operator will provide true division. The operator
1332 module provides truediv() and floordiv() functions. Augmented
1333 assignment variants are included, as are the equivalent overloadable
1334 methods and C API methods. See the PEP for a full discussion:
1335 <http://python.sf.net/peps/pep-0238.html>
1336
Tim Peters6cd6a822001-08-17 22:11:27 +00001337- Future statements are now effective in simulated interactive shells
1338 (like IDLE). This should "just work" by magic, but read Michael
1339 Hudson's "Future statements in simulated shells" PEP 264 for full
1340 details: <http://python.sf.net/peps/pep-0264.html>.
1341
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001342- The type/class unification (PEP 252-253) was integrated into the
1343 trunk and is not so tentative any more (the exact specification of
1344 some features is still tentative). A lot of work has done on fixing
1345 bugs and adding robustness and features (performance still has to
1346 come a long way).
1347
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001348- Warnings about a mismatch in the Python API during extension import
1349 now use the Python warning framework (which makes it possible to
1350 write filters for these warnings).
1351
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001352- A function's __dict__ (aka func_dict) will now always be a
1353 dictionary. It used to be possible to delete it or set it to None,
1354 but now both actions raise TypeErrors. It is still legal to set it
1355 to a dictionary object. Getting func.__dict__ before any attributes
1356 have been assigned now returns an empty dictionary instead of None.
1357
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001358- A new command line option, -E, was added which disables the use of
1359 all environment variables, or at least those that are specifically
1360 significant to Python. Usually those have a name starting with
1361 "PYTHON". This was used to fix a problem where the tests fail if
1362 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1363 older distribution.
1364
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001365Library
1366
Tim Peters5e824c32001-08-12 22:25:01 +00001367- New class Differ and new functions ndiff() and restore() in difflib.py.
1368 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001369 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001370
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001371- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1372 value using the minimal quoting required for the value; more
1373 reliable than using xml.sax.saxutils.escape() for attribute values.
1374
1375- Readline completion support for cmd.Cmd was added.
1376
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001377- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1378
1379- Added function threading.BoundedSemaphore()
1380
1381- Added Ka-Ping Yee's cgitb.py module.
1382
1383- The `new' module now exposes the CO_xxx flags.
1384
Martin v. Löwis560da622001-11-24 09:24:51 +00001385- The gc module offers the get_referents function.
1386
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001387New platforms
1388
1389C API
1390
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001391- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1392 which provide a cross-platform implementations for the
1393 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1394 the standard sprintf() and vsprintf() C lib APIs, these versions
1395 apply bounds checking on the used buffer which enhances protection
1396 against buffer overruns.
1397
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001398- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001399 and extensions using different Unicode widths is rendered next to
1400 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001401 will result in an ImportError. Unicode extensions writers must make
1402 sure to check the Unicode width compatibility in their extensions by
1403 using at least one of the mangled Unicode APIs in the extension.
1404
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001405- Two new flags METH_NOARGS and METH_O are available in method definition
1406 tables to simplify implementation of methods with no arguments and a
1407 single untyped argument. Calling such methods is more efficient than
1408 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1409 deprecated.
1410
Tim Petersc1731372001-08-04 08:12:36 +00001411Windows
1412
1413- "import module" now compiles module.pyw if it exists and nothing else
1414 relevant is found.
1415
Tim Peters20f51a72001-07-21 02:31:40 +00001416
Guido van Rossum55a78992001-07-17 17:22:32 +00001417What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001418Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001419===========================
1420
1421Core
Tim Petersa814db52001-05-14 07:05:58 +00001422
Tim Peters6d6c1a32001-08-02 04:15:00 +00001423- TENTATIVELY, a large amount of code implementing much of what's
1424 described in PEP 252 (Making Types Look More Like Classes) and PEP
1425 253 (Subtyping Built-in Types) was added. This will be released
1426 with Python 2.2a1. Documentation will be provided separately
1427 through http://www.python.org/2.2/. The purpose of releasing this
1428 with Python 2.2a1 is to test backwards compatibility. It is
1429 possible, though not likely, that a decision is made not to release
1430 this code as part of 2.2 final, if any serious backwards
1431 incompapatibilities are found during alpha testing that cannot be
1432 repaired.
1433
Guido van Rossum55a78992001-07-17 17:22:32 +00001434- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001435 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001436 more 'yield' statements. See PEP 255. Since this adds a new
1437 keyword to the language, this feature must be enabled by including a
1438 future statement: "from __future__ import generators" (see PEP 236).
1439 Generators will become a standard feature in a future release
1440 (probably 2.3). Without this future statement, 'yield' remains an
1441 ordinary identifier, but a warning is issued each time it is used.
1442 (These warnings currently don't conform to the warnings framework of
1443 PEP 230; we intend to fix this in 2.2a2.)
1444
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001445- The UTF-16 codec was modified to be more RFC compliant. It will now
1446 only remove BOM characters at the start of the string and then
1447 only if running in native mode (UTF-16-LE and -BE won't remove a
1448 leading BMO character).
1449
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001450- Strings now have a new method .decode() to complement the already
1451 existing .encode() method. These two methods provide direct access
1452 to the corresponding decoders and encoders of the registered codecs.
1453
1454 To enhance the usability of the .encode() method, the special
1455 casing of Unicode object return values was dropped (Unicode objects
1456 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001457
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001458 Both methods will now return whatever the codec in charge of the
1459 requested encoding returns as object, e.g. Unicode codecs will
1460 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1461 will return u"äöü"). This enables codec writer to create codecs
1462 for various simple to use conversions.
1463
1464 New codecs were added to demonstrate these new features (the .encode()
1465 and .decode() columns indicate the type of the returned objects):
1466
1467 Name | .encode() | .decode() | Description
1468 ----------------------------------------------------------------------
1469 uu | string | string | UU codec (e.g. for email)
1470 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001471 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001472 zlib | string | string | zlib compression
1473 hex | string | string | 2-byte hex codec
1474 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1475
Mark Hammond2a0af792001-05-14 03:09:36 +00001476- Some operating systems now support the concept of a default Unicode
1477 encoding for file system operations. Notably, Windows supports 'mbcs'
1478 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001479 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001480 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001481
1482 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001483 functions that return filenames (such as os.listdir()) to return Python
1484 string objects pre-encoded using the default file system encoding for
1485 the platform. As this encoding is likely to be different from Python's
1486 default encoding, converting this name to a Unicode object before passing
1487 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001488 would attempt to use its default encoding (generally ASCII) rather than
1489 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001490
Tim Petersa814db52001-05-14 07:05:58 +00001491 In general, this change simply removes surprises when working with
1492 Unicode and the file system, making these operations work as you expect,
1493 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001494 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001495
Tim Peters61dff2b2001-05-08 15:43:37 +00001496- Float (and complex) literals in source code were evaluated to full
1497 precision only when running from a .py file; the same code loaded from a
1498 .pyc (or .pyo) file could suffer numeric differences starting at about the
1499 12th significant decimal digit. For example, on a machine with IEEE-754
1500 floating arithmetic,
1501
1502 x = 9007199254740992.0
1503 print long(x)
1504
1505 printed 9007199254740992 if run directly from .py, but 9007199254740000
1506 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1507 str(float) instead of repr(float) when building code objects. marshal
1508 now uses repr(float) instead, which should reproduce floats to full
1509 machine precision (assuming the platform C float<->string I/O conversion
1510 functions are of good quality).
1511
1512 This may cause floating-point results to change in some cases, and
1513 usually for the better, but may also cause numerically unstable
1514 algorithms to break.
1515
Tim Peters2f228e72001-05-13 00:19:31 +00001516- The implementation of dicts suffers fewer collisions, which has speed
1517 benefits. However, the order in which dict entries appear in dict.keys(),
1518 dict.values() and dict.items() may differ from previous releases for a
1519 given dict. Nothing is defined about this order, so no program should
1520 rely on it. Nevertheless, it's easy to write test cases that rely on the
1521 order by accident, typically because of printing the str() or repr() of a
1522 dict to an "expected results" file. See Lib/test/test_support.py's new
1523 sortdict(dict) function for a simple way to display a dict in sorted
1524 order.
1525
Tim Peters7a3bfc32001-06-12 01:22:22 +00001526- Many other small changes to dicts were made, resulting in faster
1527 operation along the most common code paths.
1528
Guido van Rossum10315822001-05-01 20:54:30 +00001529- Dictionary objects now support the "in" operator: "x in dict" means
1530 the same as dict.has_key(x).
1531
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001532- The update() method of dictionaries now accepts generic mapping
1533 objects. Specifically the argument object must support the .keys()
1534 and __getitem__() methods. This allows you to say, for example,
1535 {}.update(UserDict())
1536
Guido van Rossum10315822001-05-01 20:54:30 +00001537- Iterators were added; this is a generalized way of providing values
1538 to a for loop. See PEP 234. There's a new built-in function iter()
1539 to return an iterator. There's a new protocol to get the next value
1540 from an iterator using the next() method (in Python) or the
1541 tp_iternext slot (in C). There's a new protocol to get iterators
1542 using the __iter__() method (in Python) or the tp_iter slot (in C).
1543 Iterating (i.e. a for loop) over a dictionary generates its keys.
1544 Iterating over a file generates its lines.
1545
Tim Petersf553f892001-05-01 20:45:31 +00001546- The following functions were generalized to work nicely with iterator
1547 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001548 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001549 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1550 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001551 join() method of strings
1552 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001553 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1554 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001555 right-hand side of assignment statements with multiple targets, such as
1556 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001557
Tim Petersd85e1022001-05-11 21:51:48 +00001558- Accessing module attributes is significantly faster (for example,
1559 random.random or os.path or yourPythonModule.yourAttribute).
1560
Tim Peterse63415e2001-05-08 04:38:29 +00001561- Comparing dictionary objects via == and != is faster, and now works even
1562 if the keys and values don't support comparisons other than ==.
1563
Tim Peters95bf9392001-05-10 08:32:44 +00001564- Comparing dictionaries in ways other than == and != is slower: there were
1565 insecurities in the dict comparison implementation that could cause Python
1566 to crash if the element comparison routines for the dict keys and/or
1567 values mutated the dicts. Making the code bulletproof slowed it down.
1568
Tim Peterseb28ef22001-06-02 05:27:19 +00001569- Collisions in dicts are resolved via a new approach, which can help
1570 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001571 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001572 faster now. Thanks to Christian Tismer for pointing out the cause and
1573 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001574
Tim Peters52e155e2001-06-16 05:42:57 +00001575- repr() is much faster for large containers (dict, list, tuple).
1576
1577
Tim Petersa814db52001-05-14 07:05:58 +00001578Library
1579
Fred Drake960fdf92001-07-20 18:38:26 +00001580- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1581 were added to the string module. These a locale-indenpendent
1582 constants, unlike letters, lowercase, and uppercase. These are now
1583 use in appropriate locations in the standard library.
1584
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001585- The flags used in dlopen calls can now be configured using
1586 sys.setdlopenflags and queried using sys.getdlopenflags.
1587
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001588- Fredrik Lundh's xmlrpclib is now a standard library module. This
1589 provides full client-side XML-RPC support. In addition,
1590 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1591 one asyncore-based). Thanks to Eric Raymond for the documentation.
1592
Guido van Rossum643d3912001-07-05 14:46:25 +00001593- The xrange() object is simplified: it no longer supports slicing,
1594 repetition, comparisons, efficient 'in' checking, the tolist()
1595 method, or the start, stop and step attributes. See PEP 260.
1596
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001597- A new function fnmatch.filter to filter lists of file names was added.
1598
Barry Warsawffd674d2001-05-22 16:00:10 +00001599- calendar.py uses month and day names based on the current locale.
1600
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001601- strop is now *really* obsolete (this was announced before with 1.6),
1602 and issues DeprecationWarning when used (except for the four items
1603 that are still imported into string.py).
1604
Tim Petersa814db52001-05-14 07:05:58 +00001605- Cookie.py now sorts key+value pairs by key in output strings.
1606
1607- pprint.isrecursive(object) didn't correctly identify recursive objects.
1608 Now it does.
1609
Tim Peters95b3f782001-05-14 18:39:41 +00001610- pprint functions now much faster for large containers (tuple, list, dict).
1611
Tim Peters7b9542a2001-06-10 23:40:19 +00001612- New 'q' and 'Q' format codes in the struct module, corresponding to C
1613 types "long long" and "unsigned long long" (on Windows, __int64). In
1614 native mode, these can be used only when the platform C compiler supports
1615 these types (when HAVE_LONG_LONG is #define'd by the Python config
1616 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001617 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1618 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001619
Guido van Rossum83213cc2001-06-12 16:48:52 +00001620- The site module installs a new built-in function 'help' that invokes
1621 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1622 it displays a message reminding the user to use 'help()' or
1623 'help(object)'.
1624
Tim Petersa814db52001-05-14 07:05:58 +00001625Tests
1626
1627- New test_mutants.py runs dict comparisons where the key and value
1628 comparison operators mutute the dicts randomly during comparison. This
1629 rapidly causes Python to crash under earlier releases (not for the faint
1630 of heart: it can also cause Win9x to freeze or reboot!).
1631
1632- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001633 pprint.isreadable() return sensible results. Also verifies that simple
1634 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001635
Tim Peters4324aa32001-05-28 22:30:08 +00001636C API
1637
1638- Removed the unused last_is_sticky argument from the internal
1639 _PyTuple_Resize(). If this affects you, you were cheating.
1640
1641
Guido van Rossum55a78992001-07-17 17:22:32 +00001642======================================================================
1643
1644
Guido van Rossumffe13be2001-04-16 18:46:45 +00001645What's New in Python 2.1 (final)?
1646=================================
1647
1648We only changed a few things since the last release candidate, all in
1649Python library code:
1650
1651- A bug in the locale module was fixed that affected locales which
1652 define no grouping for numeric formatting.
1653
1654- A few bugs in the weakref module's implementations of weak
1655 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1656 and the test suite was updated to check for these bugs.
1657
1658- An old bug in the os.path.walk() function (introduced in Python
1659 2.0!) was fixed: a non-existent file would cause an exception
1660 instead of being ignored.
1661
1662- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1663 PyChecker.
1664
1665
Guido van Rossum5b08f132001-04-16 02:05:23 +00001666What's New in Python 2.1c2?
1667===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001668
Guido van Rossum5b08f132001-04-16 02:05:23 +00001669A flurry of small changes, and one showstopper fixed in the nick of
1670time made it necessary to release another release candidate. The list
1671here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001672
Guido van Rossum5b08f132001-04-16 02:05:23 +00001673Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001674
Guido van Rossum5b08f132001-04-16 02:05:23 +00001675- Tim discovered a nasty bug in the dictionary code, caused by
1676 PyDict_Next() calling dict_resize(), and the GC code's use of
1677 PyDict_Next() violating an assumption in dict_items(). This was
1678 fixed with considerable amounts of band-aid, but the net effect is a
1679 saner and more robust implementation.
1680
1681- Made a bunch of symbols static that were accidentally global.
1682
1683Build and Ports
1684
1685- The setup.py script didn't check for a new enough version of zlib
1686 (1.1.3 is needed). Now it does.
1687
1688- Changed "make clean" target to also remove shared libraries.
1689
1690- Added a more general warning about the SGI Irix optimizer to README.
1691
1692Library
1693
1694- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1695 omitted the slash between host and file.html.
1696
1697- The mailbox module's _Mailbox class contained a completely broken
1698 and undocumented seek() method. Ripped it out.
1699
1700- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1701 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1702
1703- Fixed a few last-minute bugs in unittest.
1704
1705Extensions
1706
1707- Reverted the patch to the OpenSSL code in socketmodule.c to support
1708 RAND_status() and the EGD, and the subsequent patch that tried to
1709 fix it for pre-0.9.5 versions; the problem with the patch is that on
1710 some systems it issues a warning whenever socket is imported, and
1711 that's unacceptable.
1712
1713Tests
1714
1715- Fixed the pickle tests to work with "import test.test_pickle".
1716
1717- Tweaked test_locale.py to actually run the test Windows.
1718
1719- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1720 not "wb" (which is not a valid mode at all).
1721
1722- Fix pstats browser crashes. Import readline if it exists to make
1723 the user interface nicer.
1724
1725- Add "import thread" to the top of test modules that import the
1726 threading module (test_asynchat and test_threadedtempfile). This
1727 prevents test failures caused by a broken threading module resulting
1728 from a previously caught failed import.
1729
1730- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1731 needed on some platforms (e.g. Solaris 8) when the tests are run
1732 twice in succession.
1733
1734- Skip rather than fail test_sunaudiodev if no audio device is found.
1735
1736
1737What's New in Python 2.1c1?
1738===========================
1739
1740This list was significantly updated when 2.1c2 was released; the 2.1c1
1741release didn't mention most changes that were actually part of 2.1c1:
1742
1743Legal
1744
1745- Copyright was assigned to the Python Software Foundation (PSF) and a
1746 PSF license (very similar to the CNRI license) was added.
1747
1748- The CNRI copyright notice was updated to include 2001.
1749
1750Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001751
Guido van Rossumc9932722001-04-12 02:31:27 +00001752- After a public outcry, assignment to __debug__ is no longer illegal;
1753 instead, a warning is issued. It will become illegal in 2.2.
1754
Guido van Rossum5b08f132001-04-16 02:05:23 +00001755- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1756 "%#x" now always prepends "0x", even if the value is zero.
1757
1758- Fixed some nits in the bytecode compiler.
1759
1760- Fixed core dumps when calling certain kinds of non-functions.
1761
1762- Fixed various core dumps caused by reference count bugs.
1763
1764Build and Ports
1765
1766- Use INSTALL_SCRIPT to install script files.
1767
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001768- New port: SCO Unixware 7, by Billy G. Allie.
1769
Guido van Rossum5b08f132001-04-16 02:05:23 +00001770- Updated RISCOS port.
1771
1772- Updated BeOS port and notes.
1773
1774- Various other porting problems resolved.
1775
1776Library
1777
1778- The TERMIOS and SOCKET modules are now truly obsolete and
1779 unnecessary. Their symbols are incorporated in the termios and
1780 socket modules.
1781
1782- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1783 better tests for pickling.
1784
1785- threading: make Condition.wait() robust against KeyboardInterrupt.
1786
1787- zipfile: add support to zipfile to support opening an archive
1788 represented by an open file rather than a file name. Fix bug where
1789 the archive was not properly closed. Fixed a bug in this bugfix
1790 where flush() was called for a read-only file.
1791
1792- imputil: added an uninstall() method to the ImportManager.
1793
1794- Canvas: fixed bugs in lower() and tkraise() methods.
1795
1796- SocketServer: API change (added overridable close_request() method)
1797 so that the TCP server can explicitly close the request.
1798
1799- pstats: Eric Raymond added a simple interactive statistics browser,
1800 invoked when the module is run as a script.
1801
1802- locale: fixed a problem in format().
1803
1804- webbrowser: made it work when the BROWSER environment variable has a
1805 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1806 KDE 2. Fixed some other nits.
1807
1808- unittest: changes to allow using a different exception than
1809 AssertionError, and added a few more function aliases. Some other
1810 small changes.
1811
1812- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1813
1814- asynchat: fixed a critical bug in asynchat that slipped through the
1815 2.1b2 release. Fixed another rare bug.
1816
1817- Fix some unqualified except: clauses (always a bad code example).
1818
1819XML
1820
1821- pyexpat: new API get_version_string().
1822
1823- Fixed some minidom bugs.
1824
1825Extensions
1826
1827- Fixed a core dump in _weakref. Removed the weakref.mapping()
1828 function (it adds nothing to the API).
1829
1830- Rationalized the use of header files in the readline module, to make
1831 it compile (albeit with some warnings) with the very recent readline
1832 4.2, without breaking for earlier versions.
1833
1834- Hopefully fixed a buffering problem in linuxaudiodev.
1835
1836- Attempted a fix to make the OpenSSL support in the socket module
1837 work again with pre-0.9.5 versions of OpenSSL.
1838
1839Tests
1840
1841- Added a test case for asynchat and asyncore.
1842
1843- Removed coupling between tests where one test failing could break
1844 another.
1845
1846Tools
1847
1848- Ping added an interactive help browser to pydoc, fixed some nits
1849 in the rest of the pydoc code, and added some features to his
1850 inspect module.
1851
1852- An updated python-mode.el version 4.1 which integrates Ken
1853 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1854 much nicer in XEmacs and Emacs. When stepping through your program
1855 with pdb, in either the shell window or the *Python* window, the
1856 source file and line will be tracked by an arrow. Very cool!
1857
1858- IDLE: syntax warnings in interactive mode are changed into errors.
1859
1860- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001861 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001862
1863- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001864
Barry Warsaw11e89c72001-04-11 20:37:57 +00001865
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001866What's New in Python 2.1 beta 2?
1867================================
1868
Guido van Rossum053ae352001-03-22 14:17:21 +00001869(Unlisted are many fixed bugs, more documentation, etc.)
1870
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001871Core language, builtins, and interpreter
1872
Guido van Rossum053ae352001-03-22 14:17:21 +00001873- The nested scopes work (enabled by "from __future__ import
1874 nested_scopes") is completed; in particular, the future now extends
1875 into code executed through exec, eval() and execfile(), and into the
1876 interactive interpreter.
1877
1878- When calling a base class method (e.g. BaseClass.__init__(self)),
1879 this is now allowed even if self is not strictly spoken a class
1880 instance (e.g. when using metaclasses or the Don Beaudry hook).
1881
1882- Slice objects are now comparable but not hashable; this prevents
1883 dict[:] from being accepted but meaningless.
1884
1885- Complex division is now calculated using less braindead algorithms.
1886 This doesn't change semantics except it's more likely to give useful
1887 results in extreme cases. Complex repr() now uses full precision
1888 like float repr().
1889
1890- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1891
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001892- It is illegal to assign to the name __debug__, which is set when the
1893 interpreter starts. It is effectively a compile-time constant.
1894
1895- A warning will be issued if a global statement for a variable
1896 follows a use or assignment of that variable.
1897
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001898Standard library
1899
Guido van Rossum053ae352001-03-22 14:17:21 +00001900- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1901 inspired by JUnit), is now part of the standard library. You now
1902 have a choice of two testing frameworks: unittest requires you to
1903 write testcases as separate code, doctest gathers them from
1904 docstrings. Both approaches have their advantages and
1905 disadvantages.
1906
1907- A new module Tix was added, which wraps the Tix extension library
1908 for Tk. With that module, it is not necessary to statically link
1909 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1910 require" command. See Demo/tix/.
1911
1912- tzparse.py is now obsolete.
1913
1914- In gzip.py, the seek() and tell() methods are removed -- they were
1915 non-functional anyway, and it's better if callers can test for their
1916 existence with hasattr().
1917
1918Python/C API
1919
1920- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1921 that's already in the dictionary during a PyDict_Next() iteration.
1922 This used to fail occasionally when a dictionary resize operation
1923 could be triggered that would rehash all the keys. All other
1924 modifications to the dictionary are still off-limits during a
1925 PyDict_Next() iteration!
1926
1927- New extended APIs related to passing compiler variables around.
1928
1929- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1930 implement isinstance() and issubclass().
1931
1932- Py_BuildValue() now has a "D" conversion to create a Python complex
1933 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001934
Fred Drake4e262a92001-03-22 18:26:47 +00001935- Extensions types which support weak references must now set the
1936 field allocated for the weak reference machinery to NULL themselves;
1937 this is done to avoid the cost of checking each object for having a
1938 weakly referencable type in PyObject_INIT(), since most types are
1939 not weakly referencable.
1940
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001941- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1942 free variables and cell variables to and from the frame's f_locals.
1943
1944- Variants of several functions defined in pythonrun.h have been added
1945 to support the nested_scopes future statement. The variants all end
1946 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1947 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1948 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001949 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001950
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001951Distutils
1952
1953- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1954 into the release tree.
1955
Tim Peters0e57abf2001-05-02 07:39:38 +00001956- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001957 (an uninstaller, more customization of the installer's display)
1958
1959- from Jack Jansen: added Mac-specific code to generate a dialog for
1960 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001961 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001962 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001963
1964- added 'platforms' and 'keywords' to the set of metadata that can be
1965 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001966
1967- applied patches from Jason Tishler to make the compiler class work with
1968 Cygwin.
1969
1970
Tim Peters2fe289a2001-03-01 22:19:38 +00001971What's New in Python 2.1 beta 1?
1972================================
Tim Petersd66595f2001-02-04 03:09:53 +00001973
1974Core language, builtins, and interpreter
1975
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001976- Following an outcry from the community about the amount of code
1977 broken by the nested scopes feature introduced in 2.1a2, we decided
1978 to make this feature optional, and to wait until Python 2.2 (or at
1979 least 6 months) to make it standard. The option can be enabled on a
1980 per-module basis by adding "from __future__ import nested_scopes" at
1981 the beginning of a module (before any other statements, but after
1982 comments and an optional docstring). See PEP 236 (Back to the
1983 __future__) for a description of the __future__ statement. PEP 227
1984 (Statically Nested Scopes) has been updated to reflect this change,
1985 and to clarify the semantics in a number of endcases.
1986
1987- The nested scopes code, when enabled, has been hardened, and most
1988 bugs and memory leaks in it have been fixed.
1989
1990- Compile-time warnings are now generated for a number of conditions
1991 that will break or change in meaning when nested scopes are enabled:
1992
1993 - Using "from...import *" or "exec" without in-clause in a function
1994 scope that also defines a lambda or nested function with one or
1995 more free (non-local) variables. The presence of the import* or
1996 bare exec makes it impossible for the compiler to determine the
1997 exact set of local variables in the outer scope, which makes it
1998 impossible to determine the bindings for free variables in the
1999 inner scope. To avoid the warning about import *, change it into
2000 an import of explicitly name object, or move the import* statement
2001 to the global scope; to avoid the warning about bare exec, use
2002 exec...in... (a good idea anyway -- there's a possibility that
2003 bare exec will be deprecated in the future).
2004
2005 - Use of a global variable in a nested scope with the same name as a
2006 local variable in a surrounding scope. This will change in
2007 meaning with nested scopes: the name in the inner scope will
2008 reference the variable in the outer scope rather than the global
2009 of the same name. To avoid the warning, either rename the outer
2010 variable, or use a global statement in the inner function.
2011
Neil Schemenauera35c6882001-02-27 04:45:05 +00002012- An optional object allocator has been included. This allocator is
2013 optimized for Python objects and should be faster and use less memory
2014 than the standard system allocator. It is not enabled by default
2015 because of possible thread safety problems. The allocator is only
2016 protected by the Python interpreter lock and it is possible that some
2017 extension modules require a thread safe allocator. The object
2018 allocator can be enabled by providing the "--with-pymalloc" option to
2019 configure.
2020
Tim Petersd66595f2001-02-04 03:09:53 +00002021Standard library
2022
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002023- pyexpat now detects the expat version if expat.h defines it. A
2024 number of additional handlers are provided, which are only available
2025 since expat 1.95. In addition, the methods SetParamEntityParsing and
2026 GetInputContext of Parser objects are available with 1.95.x
2027 only. Parser objects now provide the ordered_attributes and
2028 specified_attributes attributes. A new module expat.model was added,
2029 which offers a number of additional constants if 1.95.x is used.
2030
2031- xml.dom offers the new functions registerDOMImplementation and
2032 getDOMImplementation.
2033
2034- xml.dom.minidom offers a toprettyxml method. A number of DOM
2035 conformance issues have been resolved. In particular, Element now
2036 has an hasAttributes method, and the handling of namespaces was
2037 improved.
2038
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002039- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2040 getting information about live Python code, and pydoc.py, a module
2041 for interactively converting docstrings to HTML or text.
2042 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002043 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002044 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2045 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002046
Tim Peters1eff7962001-03-01 02:31:33 +00002047- New library module difflib.py, primarily packaging the SequenceMatcher
2048 class at the heart of the popular ndiff.py file-comparison tool.
2049
2050- doctest.py (a framework for verifying Python code examples in docstrings)
2051 is now part of the std library.
2052
Tim Petersd66595f2001-02-04 03:09:53 +00002053Windows changes
2054
Guido van Rossume3955a82001-03-02 14:05:59 +00002055- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2056 small GUI that lets you browse the module docstrings using your
2057 default web browser.
2058
Tim Peters1eff7962001-03-01 02:31:33 +00002059- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2060 Platforms) is implemented. See
2061
2062 http://python.sourceforge.net/peps/pep-0235.html
2063
2064 for full details, especially the "Current Lower-Left Semantics" section.
2065 The new Windows import rules are simpler than before:
2066
2067 A. If the PYTHONCASEOK environment variable exists, same as
2068 before: silently accept the first case-insensitive match of any
2069 kind; raise ImportError if none found.
2070
2071 B. Else search sys.path for the first case-sensitive match; raise
2072 ImportError if none found.
2073
2074 The same rules have been implented on other platforms with case-
2075 insensitive but case-preserving filesystems too (including Cygwin, and
2076 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002077
Tim Peters25a9ce32001-02-19 07:06:36 +00002078- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2079 what it's supposed to do (and does do under NT and 2000) via direct
2080 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002081 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002082 all Win9x systems before.
2083
Tim Peters1eff7962001-03-01 02:31:33 +00002084- Build: Subproject _test (effectively) renamed to _testcapi.
2085
Tim Peters2fe289a2001-03-01 22:19:38 +00002086New platforms
2087
2088- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2089 Thanks to Steven Majewski!
2090
2091- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2092 Tishler!
2093
Guido van Rossum9089b272001-03-02 06:49:50 +00002094- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2095 Schwertberger! See RISCOS/README for more information -- it seems
2096 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002097 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002098
Tim Peters25a9ce32001-02-19 07:06:36 +00002099
Tim Petersd7b5e882001-01-25 03:36:26 +00002100What's New in Python 2.1 alpha 2?
2101=================================
Tim Peters40ead762001-01-27 05:35:26 +00002102
Tim Petersd7b5e882001-01-25 03:36:26 +00002103Core language, builtins, and interpreter
2104
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002105- Scopes nest. If a name is used in a function or class, but is not
2106 local, the definition in the nearest enclosing function scope will
2107 be used. One consequence of this change is that lambda statements
2108 could reference variables in the namespaces where the lambda is
2109 defined. In some unusual cases, this change will break code.
2110
2111 In all previous version of Python, names were resolved in exactly
2112 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002113 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002114 function A is defined within a function B, the names bound in B are
2115 not visible in A. The new rules make names bound in B visible in A,
2116 unless A contains a name binding that hides the binding in B.
2117
2118 Section 4.1 of the reference manual describes the new scoping rules
2119 in detail. The test script in Lib/test/test_scope.py demonstrates
2120 some of the effects of the change.
2121
2122 The new rules will cause existing code to break if it defines nested
2123 functions where an outer function has local variables with the same
2124 name as globals or builtins used by the inner function. Example:
2125
2126 def munge(str):
2127 def helper(x):
2128 return str(x)
2129 if type(str) != type(''):
2130 str = helper(str)
2131 return str.strip()
2132
2133 Under the old rules, the name str in helper() is bound to the
2134 builtin function str(). Under the new rules, it will be bound to
2135 the argument named str and an error will occur when helper() is
2136 called.
2137
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002138- The compiler will report a SyntaxError if "from ... import *" occurs
2139 in a function or class scope. The language reference has documented
2140 that this case is illegal, but the compiler never checked for it.
2141 The recent introduction of nested scope makes the meaning of this
2142 form of name binding ambiguous. In a future release, the compiler
2143 may allow this form when there is no possibility of ambiguity.
2144
Tim Peters40ead762001-01-27 05:35:26 +00002145- repr(string) is easier to read, now using hex escapes instead of octal,
2146 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2147
2148 >>> "\texample \r\n" + chr(0) + chr(255)
2149 '\texample \r\n\x00\xff' # in 2.1
2150 '\011example \015\012\000\377' # in 2.0
2151
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002152- Functions are now compared and hashed by identity, not by value, since
2153 the func_code attribute is writable.
2154
Fred Drakefb9d7122001-02-01 20:00:40 +00002155- Weak references (PEP 205) have been added. This involves a few
2156 changes in the core, an extension module (_weakref), and a Python
2157 module (weakref). The weakref module is the public interface. It
2158 includes support for "explicit" weak references, proxy objects, and
2159 mappings with weakly held values.
2160
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002161- A 'continue' statement can now appear in a try block within the body
2162 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002163 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002164
Tim Petersd7b5e882001-01-25 03:36:26 +00002165Standard library
2166
Barry Warsaw30dbd142001-01-31 22:14:01 +00002167- mailbox.py now has a new class, PortableUnixMailbox which is
2168 identical to UnixMailbox but uses a more portable scheme for
2169 determining From_ separators. Also, the constructors for all the
2170 classes in this module have a new optional `factory' argument, which
2171 is a callable used when new message classes must be instantiated by
2172 the next() method.
2173
Tim Petersd7b5e882001-01-25 03:36:26 +00002174- random.py is now self-contained, and offers all the functionality of
2175 the now-deprecated whrandom.py. See the docs for details. random.py
2176 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002177 and restoring the internal state of the generator; and jumpahead(n),
2178 for quickly forcing the internal state to be the same as if n calls to
2179 random() had been made. The latter is particularly useful for multi-
2180 threaded programs, creating one instance of the random.Random() class for
2181 each thread, then using .jumpahead() to force each instance to use a
2182 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002183
Tim Peters0de88fc2001-02-01 04:59:18 +00002184- random.py's seed() function is new. For bit-for-bit compatibility with
2185 prior releases, use the whseed function instead. The new seed function
2186 addresses two problems: (1) The old function couldn't produce more than
2187 about 2**24 distinct internal states; the new one about 2**45 (the best
2188 that can be done in the Wichmann-Hill generator). (2) The old function
2189 sometimes produced identical internal states when passed distinct
2190 integers, and there was no simple way to predict when that would happen;
2191 the new one guarantees to produce distinct internal states for all
2192 arguments in [0, 27814431486576L).
2193
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002194- The socket module now supports raw packets on Linux. The socket
2195 family is AF_PACKET.
2196
Tim Peters9ea17ac2001-02-02 05:57:15 +00002197- test_capi.py is a start at running tests of the Python C API. The tests
2198 are implemented by the new Modules/_testmodule.c.
2199
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002200- A new extension module, _symtable, provides provisional access to the
2201 internal symbol table used by the Python compiler. A higher-level
2202 interface will be added on top of _symtable in a future release.
2203
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002204- Removed the obsolete soundex module.
2205
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002206- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2207 the isSameNode method; NamedNodeMap the get method.
2208
2209- xml.sax.expatreader supports the lexical handler property; it
2210 generates comment, startCDATA, and endCDATA events.
2211
Tim Petersee826f82001-01-31 19:39:44 +00002212Windows changes
2213
2214- Build procedure: the zlib project is built in a different way that
2215 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002216 the zlib binary used. See PCbuild\readme.txt for details. Your old
2217 zlib-related directories can be deleted; you'll need to download fresh
2218 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002219
Tim Peters9ea17ac2001-02-02 05:57:15 +00002220- Build: New subproject _test for the benefit of test_capi.py (see above).
2221
Tim Petersb16c56f2001-02-02 21:24:51 +00002222- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2223 interface to some Python compiler internals).
2224
2225- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002226 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002227
Tim Petersa3a3a032000-11-30 05:22:44 +00002228What's New in Python 2.1 alpha 1?
2229=================================
2230
2231Core language, builtins, and interpreter
2232
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002233- There is a new Unicode companion to the PyObject_Str() API
2234 called PyObject_Unicode(). It behaves in the same way as the
2235 former, but assures that the returned value is an Unicode object
2236 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002237
Guido van Rossumf98eda02001-01-17 15:54:45 +00002238- The comparison operators support "rich comparison overloading" (PEP
2239 207). C extension types can provide a rich comparison function in
2240 the new tp_richcompare slot in the type object. The cmp() function
2241 and the C function PyObject_Compare() first try the new rich
2242 comparison operators before trying the old 3-way comparison. There
2243 is also a new C API PyObject_RichCompare() (which also falls back on
2244 the old 3-way comparison, but does not constrain the outcome of the
2245 rich comparison to a Boolean result).
2246
2247 The rich comparison function takes two objects (at least one of
2248 which is guaranteed to have the type that provided the function) and
2249 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2250 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2251 object, which may be NotImplemented (in which case the tp_compare
2252 slot function is used as a fallback, if defined).
2253
2254 Classes can overload individual comparison operators by defining one
2255 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002256 __ge__. There are no explicit "reflected argument" versions of
2257 these; instead, __lt__ and __gt__ are each other's reflection,
2258 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2259 reflection (similar at the C level). No other implications are
2260 made; in particular, Python does not assume that == is the Boolean
2261 inverse of !=, or that < is the Boolean inverse of >=. This makes
2262 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002263
2264 Classes or types that want to implement (in)equality tests but not
2265 the ordering operators (i.e. unordered types) should implement ==
2266 and !=, and raise an error for the ordering operators.
2267
Guido van Rossuma88479f2001-01-18 14:28:08 +00002268 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002269 Boolean; e.g. a matrix type might want to return a matrix of bits
2270 for A < B, giving elementwise comparisons. Such types should ensure
2271 that any interpretation of their value in a Boolean context raises
2272 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2273 at the C level) to always raise an exception.
2274
Guido van Rossuma88479f2001-01-18 14:28:08 +00002275- Complex numbers use rich comparisons to define == and != but raise
2276 an exception for <, <=, > and >=. Unfortunately, this also means
2277 that cmp() of two complex numbers raises an exception when the two
2278 numbers differ. Since it is not mathematically meaningful to compare
2279 complex numbers except for equality, I hope that this doesn't break
2280 too much code.
2281
Tim Peters3389f192001-02-18 08:48:49 +00002282- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002283 not defined by the language, other than that it's arbitrary but
2284 consistent (see the Reference Manual). An implementation detail changed
2285 in 2.1a1 such that None now compares less than any other object. Code
2286 relying on this new behavior (like code that relied on the previous
2287 behavior) does so at its own risk.
2288
Barry Warsaw573b5412001-01-15 20:43:18 +00002289- Functions and methods now support getting and setting arbitrarily
2290 named attributes (PEP 232). Functions have a new __dict__
2291 (a.k.a. func_dict) which hold the function attributes. Methods get
2292 and set attributes on their underlying im_func. It is a TypeError
2293 to set an attribute on a bound method.
2294
Guido van Rossum051e3352001-01-15 19:11:10 +00002295- The xrange() object implementation has been improved so that
2296 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2297 limitation that in this case len(xrange(sys.maxint)) can't be
2298 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2299 work fine as long as the index i doesn't actually reach 2**31.
2300 (Python uses regular ints for sequence and string indices; fixing
2301 that is much more work.)
2302
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002303- Two changes to from...import:
2304
Guido van Rossumba381232001-02-03 15:06:40 +00002305 1) "from M import X" now works even if (after loading module M)
2306 sys.modules['M'] is not a real module; it's basically a getattr()
2307 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002308
2309 2) "from M import *" now looks for M.__all__ to decide which names to
2310 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2311 filters out names starting with '_' as before. Whether or not
2312 __all__ exists, there's no restriction on the type of M.
2313
Guido van Rossumf61f1662001-01-10 20:13:55 +00002314- File objects have a new method, xreadlines(). This is the fastest
2315 way to iterate over all lines in a file:
2316
2317 for line in file.xreadlines():
2318 ...do something to line...
2319
2320 See the xreadlines module (mentioned below) for how to do this for
2321 other file-like objects.
2322
2323- Even if you don't use file.xreadlines(), you may expect a speedup on
2324 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002325 quite a bit in platform-specific ways: on systems (like Linux) that
2326 support flockfile(), getc_unlocked(), and funlockfile(), those are
2327 used by default. On systems (like Windows) without getc_unlocked(),
2328 a complicated (but still thread-safe) method using fgets() is used by
2329 default.
2330
Tim Petersd52269b2001-01-25 06:23:18 +00002331 You can force use of the fgets() method by #define'ing
2332 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002333 getc_unlocked()).
2334
Tim Petersd52269b2001-01-25 06:23:18 +00002335 You can force fgets() not to be used by #define'ing
2336 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002337 test_bufio.py fails -- and let us know if it does!).
2338
2339- In addition, the fileinput module, while still slower than the other
2340 methods on most platforms, has been sped up too, by using
2341 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002342
2343- Support for run-time warnings has been added, including a new
2344 command line option (-W) to specify the disposition of warnings.
2345 See the description of the warnings module below.
2346
2347- Extensive changes have been made to the coercion code. This mostly
2348 affects extension modules (which can now implement mixed-type
2349 numerical operators without having to use coercion), but
2350 occasionally, in boundary cases the coercion semantics have changed
2351 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002352 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002353 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002354 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002355
Guido van Rossumf98eda02001-01-17 15:54:45 +00002356- In connection with the coercion changes, a new built-in singleton
2357 object, NotImplemented is defined. This can be returned for
2358 operations that wish to indicate they are not implemented for a
2359 particular combination of arguments. From C, this is
2360 Py_NotImplemented.
2361
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002362- The interpreter accepts now bytecode files on the command line even
2363 if they do not have a .pyc or .pyo extension. On Linux, after executing
2364
Martin v. Löwise214baa2001-02-04 22:37:56 +00002365import imp,sys,string
2366magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2367reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2368open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002369
2370 any byte code file can be used as an executable (i.e. as an argument
2371 to execve(2)).
2372
Tim Peters9940b802000-12-01 07:59:35 +00002373- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002374 character. In 1.6 and earlier, they never produced a sign,
2375 and raised an error if the value of the long was too large
2376 to fit in a Python int. In 2.0, they produced a sign if and
2377 only if too large to fit in an int. This was inconsistent
2378 across platforms (because the size of an int varies across
2379 platforms), and inconsistent with hex() and oct(). Example:
2380
2381 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002382 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002383 'ffffffbe' # in 2.0 and before, on 32-bit machines
2384 >>> hex(-0x42L)
2385 '-0x42L' # in all versions of Python
2386
Tim Peters9940b802000-12-01 07:59:35 +00002387 The behavior of %d formats for negative Python longs remains
2388 the same as in 2.0 (although in 1.6 and before, they raised
2389 an error if the long didn't fit in a Python int).
2390
2391 %u formats don't make sense for Python longs, but are allowed
2392 and treated the same as %d in 2.1. In 2.0, a negative long
2393 formatted via %u produced a sign if and only if too large to
2394 fit in an int. In 1.6 and earlier, a negative long formatted
2395 via %u raised an error if it was too big to fit in an int.
2396
Guido van Rossum3661d392000-12-12 22:10:31 +00002397- Dictionary objects have an odd new method, popitem(). This removes
2398 an arbitrary item from the dictionary and returns it (in the form of
2399 a (key, value) pair). This can be useful for algorithms that use a
2400 dictionary as a bag of "to do" items and repeatedly need to pick one
2401 item. Such algorithms normally end up running in quadratic time;
2402 using popitem() they can usually be made to run in linear time.
2403
Tim Peters36cdad12000-12-29 02:06:45 +00002404Standard library
2405
Thomas Woutersfe385252001-01-19 23:16:56 +00002406- In the time module, the time argument to the functions strftime,
2407 localtime, gmtime, asctime and ctime is now optional, defaulting to
2408 the current time (in the local timezone).
2409
Guido van Rossumda91f222001-01-15 16:36:08 +00002410- The ftplib module now defaults to passive mode, which is deemed a
2411 more useful default given that clients are often inside firewalls
2412 these days. Note that this could break if ftplib is used to connect
2413 to a *server* that is inside a firewall, from outside; this is
2414 expected to be a very rare situation. To fix that, you can call
2415 ftp.set_pasv(0).
2416
Martin v. Löwis10a27872001-01-13 09:54:41 +00002417- The module site now treats .pth files not only for path configuration,
2418 but also supports extensions to the initialization code: Lines starting
2419 with import are executed.
2420
Guido van Rossumf61f1662001-01-10 20:13:55 +00002421- There's a new module, warnings, which implements a mechanism for
2422 issuing and filtering warnings. There are some new built-in
2423 exceptions that serve as warning categories, and a new command line
2424 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2425 turns warnings into errors). warnings.warn(message[, category])
2426 issues a warning message; this can also be called from C as
2427 PyErr_Warn(category, message).
2428
2429- A new module xreadlines was added. This exports a single factory
2430 function, xreadlines(). The intention is that this code is the
2431 absolutely fastest way to iterate over all lines in an open
2432 file(-like) object:
2433
2434 import xreadlines
2435 for line in xreadlines.xreadlines(file):
2436 ...do something to line...
2437
2438 This is equivalent to the previous the speed record holder using
2439 file.readlines(sizehint). Note that if file is a real file object
2440 (as opposed to a file-like object), this is equivalent:
2441
2442 for line in file.xreadlines():
2443 ...do something to line...
2444
Tim Peters36cdad12000-12-29 02:06:45 +00002445- The bisect module has new functions bisect_left, insort_left,
2446 bisect_right and insort_right. The old names bisect and insort
2447 are now aliases for bisect_right and insort_right. XXX_right
2448 and XXX_left methods differ in what happens when the new element
2449 compares equal to one or more elements already in the list: the
2450 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002451 right. Code that doesn't care where equal elements end up should
2452 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002453
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002454- The new curses.panel module wraps the panel library that forms part
2455 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2456
Guido van Rossumf61f1662001-01-10 20:13:55 +00002457- The SocketServer module now sets the allow_reuse_address flag by
2458 default in the TCPServer class.
2459
2460- A new function, sys._getframe(), returns the stack frame pointer of
2461 the caller. This is intended only as a building block for
2462 higher-level mechanisms such as string interpolation.
2463
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002464- The pyexpat module supports a number of new handlers, which are
2465 available only in expat 1.2. If invocation of a callback fails, it
2466 will report an additional frame in the traceback. Parser objects
2467 participate now in garbage collection. If expat reports an unknown
2468 encoding, pyexpat will try to use a Python codec; that works only
2469 for single-byte charsets. The parser type objects is exposed as
2470 XMLParserObject.
2471
2472- xml.dom now offers standard definitions for symbolic node type and
2473 exception code constants, and a hierarchy of DOM exceptions. minidom
2474 was adjusted to use them.
2475
2476- The conformance of xml.dom.minidom to the DOM specification was
2477 improved. It detects a number of additional error cases; the
2478 previous/next relationship works even when the tree is modified;
2479 Node supports the normalize() method; NamedNodeMap, DocumentType and
2480 DOMImplementation classes were added; Element supports the
2481 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2482 method.
2483
Guido van Rossumf61f1662001-01-10 20:13:55 +00002484Build issues
2485
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002486- For Unix (and Unix-compatible) builds, configuration and building of
2487 extension modules is now greatly automated. Rather than having to
2488 edit the Modules/Setup file to indicate which modules should be
2489 built and where their include files and libraries are, a
2490 distutils-based setup.py script now takes care of building most
2491 extension modules. All extension modules built this way are built
2492 as shared libraries. Only a few modules that must be linked
2493 statically are still listed in the Setup file; you won't need to
2494 edit their configuration.
2495
2496- Python should now build out of the box on Cygwin. If it doesn't,
2497 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002498
2499- Python now always uses its own (renamed) implementation of getopt()
2500 -- there's too much variation among C library getopt()
2501 implementations.
2502
2503- C++ compilers are better supported; the CXX macro is always set to a
2504 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002505
Tim Petersd92dfe02000-12-12 01:18:41 +00002506Windows changes
2507
2508- select module: By default under Windows, a select() call
2509 can specify no more than 64 sockets. Python now boosts
2510 this Microsoft default to 512. If you need even more than
2511 that, see the MS docs (you'll need to #define FD_SETSIZE
2512 and recompile Python from source).
2513
Guido van Rossumf61f1662001-01-10 20:13:55 +00002514- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2515 subdirectory is no more!
2516
Tim Petersa3a3a032000-11-30 05:22:44 +00002517
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002518What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002519=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002520
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002521Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002522changes are in the file HISTORY. If you are making the jump directly
2523from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2524HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002525
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002526Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2527the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2528http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002529
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002530--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002531
2532======================================================================
2533
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002534What's new in 2.0 (since release candidate 1)?
2535==============================================
2536
2537Standard library
2538
2539- The copy_reg module was modified to clarify its intended use: to
2540 register pickle support for extension types, not for classes.
2541 pickle() will raise a TypeError if it is passed a class.
2542
2543- Fixed a bug in gettext's "normalize and expand" code that prevented
2544 it from finding an existing .mo file.
2545
2546- Restored support for HTTP/0.9 servers in httplib.
2547
Tim Peters989b7b92000-10-16 20:24:53 +00002548- The math module was changed to stop raising OverflowError in case of
2549 underflow, and return 0 instead in underflow cases. Whether Python
2550 used to raise OverflowError in case of underflow was platform-
2551 dependent (it did when the platform math library set errno to ERANGE
2552 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002553
2554- Fixed a bug in StringIO that occurred when the file position was not
2555 at the end of the file and write() was called with enough data to
2556 extend past the end of the file.
2557
2558- Fixed a bug that caused Tkinter error messages to get lost on
2559 Windows. The bug was fixed by replacing direct use of
2560 interp->result with Tcl_GetStringResult(interp).
2561
2562- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2563 redirect response.
2564
2565- Several changes were made to distutils: Some debugging code was
2566 removed from util. Fixed the installer used when an external zip
2567 program (like WinZip) is not found; the source code for this
2568 installer is in Misc/distutils. check_lib() was modified to behave
2569 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2570 test for whether installed modules are on sys.path was changed to
2571 use both normcase() and normpath().
2572
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002573- Several minor bugs were fixed in the xml package (the minidom,
2574 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002575
2576- The regression test driver (regrtest.py) behavior when invoked with
2577 -l changed: It now reports a count of objects that are recognized as
2578 garbage but not freed by the garbage collector.
2579
Tim Peters989b7b92000-10-16 20:24:53 +00002580- The regression test for the math module was changed to test
2581 exceptional behavior when the test is run in verbose mode. Python
2582 cannot yet guarantee consistent exception behavior across platforms,
2583 so the exception part of test_math is run only in verbose mode, and
2584 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002585
2586Internals
2587
2588- PyOS_CheckStack() has been disabled on Win64, where it caused
2589 test_sre to fail.
2590
2591Build issues
2592
2593- Changed compiler flags, so that gcc is always invoked with -Wall and
2594 -Wstrict-prototypes. Users compiling Python with GCC should see
2595 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002596 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002597 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002598
Tim Petersa3a3a032000-11-30 05:22:44 +00002599- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002600
2601Tools and other miscellany
2602
2603- The compiler in Tools/compiler was updated to support the new
2604 language features introduced in 2.0: extended print statement, list
2605 comprehensions, and augmented assignments. The new compiler should
2606 also be backwards compatible with Python 1.5.2; the compiler will
2607 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002608 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002609
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002610What's new in 2.0 release candidate 1 (since beta 2)?
2611=====================================================
2612
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002613What is release candidate 1?
2614
2615We believe that release candidate 1 will fix all known bugs that we
2616intend to fix for the 2.0 final release. This release should be a bit
2617more stable than the previous betas. We would like to see even more
2618widespread testing before the final release, so we are producing this
2619release candidate. The final release will be exactly the same unless
2620any show-stopping (or brown bag) bugs are found by testers of the
2621release candidate.
2622
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002623All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002624to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002625
2626Core language, builtins, and interpreter
2627
2628- A bug that caused crashes when __coerce__ was used with augmented
2629 assignment, e.g. +=, was fixed.
2630
2631- Raise ZeroDivisionError when raising zero to a negative number,
2632 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2633 power operator and the result of math.pow(0.0, -2.0) will vary by
2634 platform. On Linux, it raises a ValueError.
2635
2636- A bug in Unicode string interpolation was fixed that occasionally
2637 caused errors with formats including "%%". For example, the
2638 following expression "%% %s" % u"abc" no longer raises a TypeError.
2639
2640- Compilation of deeply nested expressions raises MemoryError instead
2641 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2642
2643- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2644 rendering them useless. They are now written in binary mode again.
2645
2646Standard library
2647
2648- Keyword arguments are now accepted for most pattern and match object
2649 methods in SRE, the standard regular expression engine.
2650
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002651- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002652 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002653
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002654- Several bugs in the Unicode handling and error handling in _tkinter
2655 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002656
2657- Fix memory management errors in Merge() and Tkapp_Call() routines.
2658
2659- Several changes were made to cStringIO to make it compatible with
2660 the file-like object interface and with StringIO. If operations are
2661 performed on a closed object, an exception is raised. The truncate
2662 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002663 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002664
2665- There were many changes made to the linuxaudiodev module and its
2666 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002667 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002668
2669 Note that this module is named poorly, because it should work
2670 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002671 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002672
2673 The module now raises exceptions when errors occur instead of
2674 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2675 audio) and defines a getptr() method that calls the
2676 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2677
2678- The library_version attribute, introduced in an earlier beta, was
2679 removed because it can not be supported with early versions of the C
2680 readline library, which provides no way to determine the version at
2681 compile-time.
2682
2683- The binascii module is now enabled on Win64.
2684
Tim Peters46446d62000-10-09 21:19:31 +00002685- tokenize.py no longer suffers "recursion depth" errors when parsing
2686 programs with very long string literals.
2687
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002688Internals
2689
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002690- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002691 which is called when the interpreter starts up to determine where
2692 the standard library is installed. These vulnerabilities affect all
2693 previous versions of Python and can be exploited by setting very
2694 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2695 setuid Python script, although use of the wrapper in
2696 Misc/setuid-prog.c will eliminate the vulnerability.
2697
2698- Fixed garbage collection bugs in instance creation that were
2699 triggered when errors occurred during initialization. The solution,
2700 applied in cPickle and in PyInstance_New(), is to call
2701 PyObject_GC_Init() after the initialization of the object's
2702 container attributes is complete.
2703
2704- pyexpat adds definitions of PyModule_AddStringConstant and
2705 PyModule_AddObject if the Python version is less than 2.0, which
2706 provides compatibility with PyXML on Python 1.5.2.
2707
2708- If the platform has a bogus definition for LONG_BIT (the number of
2709 bits in a long), an error will be reported at compile time.
2710
2711- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2712 collection crashes and possibly other, unreported crashes.
2713
2714- Fixed a memory leak in _PyUnicode_Fini().
2715
2716Build issues
2717
2718- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002719 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002720 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002721
2722- The mmap.PAGESIZE constant is now initialized using sysconf when
2723 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2724
2725- The md5 file should now compile on all platforms.
2726
2727- The select module now compiles on platforms that do not define
2728 POLLRDNORM and related constants.
2729
2730- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002731 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002732
Jeremy Hylton10921202000-10-09 18:34:12 +00002733- BeOS: A number of changes were made to the build and installation
2734 process. ar-fake now operates on a directory of object files.
2735 dl_export.h is gone, and its macros now appear on the mwcc command
2736 line during build on PPC BeOS.
2737
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002738- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002739 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002740
2741- Cygwin: Support for shared libraries, Tkinter, and sockets.
2742
2743- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2744
2745Tools and other miscellany
2746
2747- Removed debugging prints from main used with freeze.
2748
Tim Peters46446d62000-10-09 21:19:31 +00002749- IDLE auto-indent no longer crashes when it encounters Unicode
2750 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002751
2752What's new in 2.0 beta 2 (since beta 1)?
2753========================================
2754
2755Core language, builtins, and interpreter
2756
Tim Peters482c0212000-09-26 06:33:09 +00002757- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002758 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002759
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002760- Add -h and -V command line options to print the usage message and
2761 Python version number and exit immediately.
2762
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002763- eval() and exec accept Unicode objects as code parameters.
2764
2765- getattr() and setattr() now also accept Unicode objects for the
2766 attribute name, which are converted to strings using the default
2767 encoding before lookup.
2768
2769- Multiplication on string and Unicode now does proper bounds
2770 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2771 string is too long."
2772
2773- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002774 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002775
Jeremy Hylton1b618592000-09-26 05:32:36 +00002776
2777Standard library and extensions
2778
Guido van Rossum5b08f132001-04-16 02:05:23 +00002779- socket module: the OpenSSL code now adds support for RAND_status()
2780 and EGD (Entropy Gathering Device).
2781
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002782- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002783 argument checking; it still takes no arguments.
2784
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002785- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002786
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002787- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002788
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002789- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002790
2791- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793
2794- copy: Copy Unicode objects atomically.
2795
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002796- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002797
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002798- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002799
Fred Drake67233bc2000-09-26 16:40:27 +00002800- dbm: Add get() and setdefault() methods to dbm object. Add constant
2801 `library' to module that names the library used. Added doc strings
2802 and method names to error messages. Uses configure to determine
2803 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2804 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002805
2806- distutils: Update to version 0.9.3.
2807
2808- dl: Add several dl.RTLD_ constants.
2809
2810- fpectl: Now supported on FreeBSD.
2811
2812- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2813 found by the collector will be saved in gc.garbage. This is useful
2814 for debugging a program that creates reference cycles.
2815
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002816- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002817 of HTTP class. Do not close socket on zero-length response. Do not
2818 crash when server sends invalid content-length header.
2819
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002820- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002821
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002822- marshal: When reading a short, sign-extend on platforms where shorts
2823 are bigger than 16 bits. When reading a long, repair the unportable
2824 sign extension that was being done for 64-bit machines. (It assumed
2825 that signed right shift sign-extends.)
2826
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002827- operator: Add contains(), invert(), __invert__() as aliases for
2828 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002829
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002830- os: Add support for popen2() and popen3() on all platforms where
2831 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002832
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002833- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002834 clicking on a file in Explorer (or passing the file name to the
2835 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002836
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002837- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002838 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
2840- pickle: Now raises ValueError when an invalid pickle that contains
2841 a non-string repr where a string repr was expected. This behavior
2842 matches cPickle.
2843
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002844- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002845
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002846- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002847
2848- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002849 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002850 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002851
2852- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002853 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002854
2855- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002856 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002857 few cycles during startup since the first call to
2858 setdefaultencoding() will initialize the codec registry and the
2859 encodings package.
2860
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002861- socket: Support for size hint in readlines() method of object returned
2862 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002863
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002864- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002865 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002866 is followed by whitespace.
2867
Tim Petersa3a3a032000-11-30 05:22:44 +00002868- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002869
2870- struct: Check ranges for bytes and shorts.
2871
2872- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002873 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874
2875- Tkinter: Image objects are now guaranteed to have unique ids. Set
2876 event.delta to zero if Tk version doesn't support mousewheel.
2877 Removed some debugging prints.
2878
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002879- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002880
Fred Drake67233bc2000-09-26 16:40:27 +00002881- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002882 which works around a bug in Norton AntiVirus 2000 that leads directly
2883 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002884
2885- xml: New version detection code allows PyXML to override standard
2886 XML package if PyXML version is greater than 0.6.1.
2887
Fred Drake64bb3802000-09-26 16:21:35 +00002888- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2889 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2890 tree only for nodes which are sufficiently interesting to a specific
2891 application. Does not provide the HTML-specific extensions. Still
2892 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002893
Fred Drake64bb3802000-09-26 16:21:35 +00002894- xml.sax: SAX 2 support for Python, including all the handler
2895 interfaces needed to process XML 1.0 compliant XML. Some
2896 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002897
Fred Drake64bb3802000-09-26 16:21:35 +00002898- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2899 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002900
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002901
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902C API
2903
2904- Add three new convenience functions for module initialization --
2905 PyModule_AddObject(), PyModule_AddIntConstant(), and
2906 PyModule_AddStringConstant().
2907
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002908- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002909 removed and add #error to Python.h if NULL isn't defined after
2910 #include of stdio.h.
2911
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002912- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002913 backwards compatibility (at the source level) with old extensions.
2914
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002915- A wrapper API was added for signal() and sigaction(). Instead of
2916 either function, always use PyOS_getsig() to get a signal handler
2917 and PyOS_setsig() to set one. A new convenience typedef
2918 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002919
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002920- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002921 internal data buffer and size of a string object -- or the default
2922 encoded version of a Unicode object.
2923
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002924- PyString_Size() and PyString_AsString() accept Unicode objects.
2925
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002926- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002927 exists). INT_MAX and LONG_MAX will always be defined, even if
2928 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002929
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002930- PyFloat_FromString takes a second argument, pend, that was
2931 effectively useless. It is now officially useless but preserved for
2932 backwards compatibility. If the pend argument is not NULL, *pend is
2933 set to NULL.
2934
2935- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2936 for the attribute name. See note on getattr() above.
2937
2938- A few bug fixes to argument processing for Unicode.
2939 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2940 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2941 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002942 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002943
2944- Py_BuildValue accepts B format (for bgen-generated code).
2945
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002946
Jeremy Hylton1b618592000-09-26 05:32:36 +00002947Internals
2948
2949- On Unix, fix code for finding Python installation directory so that
2950 it works when argv[0] is a relative path.
2951
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002952- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002953 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002954 rather than by generating a copy of the object.
2955
Tim Peters482c0212000-09-26 06:33:09 +00002956- Several of the internal Unicode tables are much smaller now, and
2957 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002958
Jeremy Hylton97693b02000-09-26 17:42:51 +00002959- In the garbage collector: Fixed bug in collection of tuples. Fixed
2960 bug that caused some instances to be removed from the container set
2961 while they were still live. Fixed parsing in gc.set_debug() for
2962 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002963
2964- Fixed refcount problem in instance deallocation that only occurred
2965 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2966
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002967- On Windows, getpythonregpath is now protected against null data in
2968 registry key.
2969
2970- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002971 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002972
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002973
Jeremy Hylton1b618592000-09-26 05:32:36 +00002974Build and platform-specific issues
2975
2976- Better support of GNU Pth via --with-pth configure option.
2977
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002978- Python/C API now properly exposed to dynamically-loaded extension
2979 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002980
2981- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2982 Don't define MS_SYNC to be zero when it is undefined. Added missing
2983 prototypes in posixmodule.c.
2984
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002985- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002986 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002987
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002988- Fix largefile support on older NetBSD systems and OpenBSD by adding
2989 define for TELL64.
2990
2991
2992Tools and other miscellany
2993
2994- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2995
2996- freeze: The modulefinder now works with 2.0 opcodes.
2997
Tim Petersa3a3a032000-11-30 05:22:44 +00002998- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002999 Move hackery of sys.argv until after the Tk instance has been
3000 created, which allows the application-specific Tkinter
3001 initialization to be executed if present; also pass an explicit
3002 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003003
Jeremy Hylton1b618592000-09-26 05:32:36 +00003004
3005What's new in 2.0 beta 1?
3006=========================
3007
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003008Source Incompatibilities
3009------------------------
3010
3011None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3012such as single-argument append(), connect() and bind(), and changes to
3013str(long) and repr(float).
3014
3015
3016Binary Incompatibilities
3017------------------------
3018
3019- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3020with Python 2.0; these extensions will have to be rebuilt for Python
30212.0.
3022
3023- On Windows, attempting to import a third party extension built for
3024Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3025can do about this. Check your PYTHONPATH environment variable!
3026
3027- Python bytecode files (*.pyc and *.pyo) are not compatible between
3028releases.
3029
3030
3031Overview of Changes Since 1.6
3032-----------------------------
3033
3034There are many new modules (including brand new XML support through
3035the xml package, and i18n support through the gettext module); a list
3036of all new modules is included below. Lots of bugs have been fixed.
3037
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003038The process for making major new changes to the language has changed
3039since Python 1.6. Enhancements must now be documented by a Python
3040Enhancement Proposal (PEP) before they can be accepted.
3041
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003042There are several important syntax enhancements, described in more
3043detail below:
3044
3045 - Augmented assignment, e.g. x += 1
3046
3047 - List comprehensions, e.g. [x**2 for x in range(10)]
3048
3049 - Extended import statement, e.g. import Module as Name
3050
3051 - Extended print statement, e.g. print >> file, "Hello"
3052
3053Other important changes:
3054
3055 - Optional collection of cyclical garbage
3056
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003057Python Enhancement Proposal (PEP)
3058---------------------------------
3059
3060PEP stands for Python Enhancement Proposal. A PEP is a design
3061document providing information to the Python community, or describing
3062a new feature for Python. The PEP should provide a concise technical
3063specification of the feature and a rationale for the feature.
3064
3065We intend PEPs to be the primary mechanisms for proposing new
3066features, for collecting community input on an issue, and for
3067documenting the design decisions that have gone into Python. The PEP
3068author is responsible for building consensus within the community and
3069documenting dissenting opinions.
3070
3071The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003072
3073Augmented Assignment
3074--------------------
3075
3076This must have been the most-requested feature of the past years!
3077Eleven new assignment operators were added:
3078
Guido van Rossume905e952000-09-05 12:42:46 +00003079 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003080
3081For example,
3082
3083 A += B
3084
3085is similar to
3086
3087 A = A + B
3088
3089except that A is evaluated only once (relevant when A is something
3090like dict[index].attr).
3091
3092However, if A is a mutable object, A may be modified in place. Thus,
3093if A is a number or a string, A += B has the same effect as A = A+B
3094(except A is only evaluated once); but if a is a list, A += B has the
3095same effect as A.extend(B)!
3096
3097Classes and built-in object types can override the new operators in
3098order to implement the in-place behavior; the not-in-place behavior is
3099used automatically as a fallback when an object doesn't implement the
3100in-place behavior. For classes, the method name is derived from the
3101method name for the corresponding not-in-place operator by inserting
3102an 'i' in front of the name, e.g. __iadd__ implements in-place
3103__add__.
3104
3105Augmented assignment was implemented by Thomas Wouters.
3106
3107
3108List Comprehensions
3109-------------------
3110
3111This is a flexible new notation for lists whose elements are computed
3112from another list (or lists). The simplest form is:
3113
3114 [<expression> for <variable> in <sequence>]
3115
Guido van Rossum56db0952000-09-06 23:34:25 +00003116For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003117This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003118
3119You can also add a condition:
3120
3121 [<expression> for <variable> in <sequence> if <condition>]
3122
3123For example, [w for w in words if w == w.lower()] would yield the list
3124of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003125than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003126
3127You can also have nested for loops and more than one 'if' clause. For
3128example, here's a function that flattens a sequence of sequences::
3129
3130 def flatten(seq):
3131 return [x for subseq in seq for x in subseq]
3132
3133 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3134
3135This prints
3136
3137 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3138
3139List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003140Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003141
3142
3143Extended Import Statement
3144-------------------------
3145
3146Many people have asked for a way to import a module under a different
3147name. This can be accomplished like this:
3148
3149 import foo
3150 bar = foo
3151 del foo
3152
3153but this common idiom gets old quickly. A simple extension of the
3154import statement now allows this to be written as follows:
3155
3156 import foo as bar
3157
3158There's also a variant for 'from ... import':
3159
3160 from foo import bar as spam
3161
3162This also works with packages; e.g. you can write this:
3163
3164 import test.regrtest as regrtest
3165
3166Note that 'as' is not a new keyword -- it is recognized only in this
3167context (this is only possible because the syntax for the import
3168statement doesn't involve expressions).
3169
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003170Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003171
3172
3173Extended Print Statement
3174------------------------
3175
3176Easily the most controversial new feature, this extension to the print
3177statement adds an option to make the output go to a different file
3178than the default sys.stdout.
3179
3180For example, to write an error message to sys.stderr, you can now
3181write:
3182
3183 print >> sys.stderr, "Error: bad dog!"
3184
3185As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003186evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003187
3188 print >> None, "Hello world"
3189
3190is equivalent to
3191
3192 print "Hello world"
3193
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003194Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003195
3196
3197Optional Collection of Cyclical Garbage
3198---------------------------------------
3199
3200Python is now equipped with a garbage collector that can hunt down
3201cyclical references between Python objects. It's no replacement for
3202reference counting; in fact, it depends on the reference counts being
3203correct, and decides that a set of objects belong to a cycle if all
3204their reference counts can be accounted for from their references to
3205each other. This devious scheme was first proposed by Eric Tiedemann,
3206and brought to implementation by Neil Schemenauer.
3207
3208There's a module "gc" that lets you control some parameters of the
3209garbage collection. There's also an option to the configure script
3210that lets you enable or disable the garbage collection. In 2.0b1,
3211it's on by default, so that we (hopefully) can collect decent user
3212experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003213performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003214off by default in the final 2.0 release.
3215
3216
3217Smaller Changes
3218---------------
3219
3220A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3221map(None, seq1, seq2, ...) when the sequences have the same length;
3222i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3223the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003224zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003225
3226sys.version_info is a tuple (major, minor, micro, level, serial).
3227
3228Dictionaries have an odd new method, setdefault(key, default).
3229dict.setdefault(key, default) returns dict[key] if it exists; if not,
3230it sets dict[key] to default and returns that value. Thus:
3231
3232 dict.setdefault(key, []).append(item)
3233
3234does the same work as this common idiom:
3235
3236 if not dict.has_key(key):
3237 dict[key] = []
3238 dict[key].append(item)
3239
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003240There are two new variants of SyntaxError that are raised for
3241indentation-related errors: IndentationError and TabError.
3242
3243Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3244escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003245
3246The limits on the size of expressions and file in Python source code
3247have been raised from 2**16 to 2**32. Previous versions of Python
3248were limited because the maximum argument size the Python VM accepted
3249was 2**16. This limited the size of object constructor expressions,
3250e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3251limit was raised thanks to a patch by Charles Waldman that effectively
3252fixes the problem. It is now much more likely that you will be
3253limited by available memory than by an arbitrary limit in Python.
3254
3255The interpreter's maximum recursion depth can be modified by Python
3256programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3257limit is the maximum number of recursive calls that can be made by
3258Python code. The limit exists to prevent infinite recursion from
3259overflowing the C stack and causing a core dump. The default value is
32601000. The maximum safe value for a particular platform can be found
3261by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003262
3263New Modules and Packages
3264------------------------
3265
3266atexit - for registering functions to be called when Python exits.
3267
3268imputil - Greg Stein's alternative API for writing custom import
3269hooks.
3270
3271pyexpat - an interface to the Expat XML parser, contributed by Paul
3272Prescod.
3273
3274xml - a new package with XML support code organized (so far) in three
3275subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3276would fill a volume. There's a special feature whereby a
3277user-installed package named _xmlplus overrides the standard
3278xmlpackage; this is intended to give the XML SIG a hook to distribute
3279backwards-compatible updates to the standard xml package.
3280
3281webbrowser - a platform-independent API to launch a web browser.
3282
3283
Guido van Rossume905e952000-09-05 12:42:46 +00003284Changed Modules
3285---------------
3286
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003287array -- new methods for array objects: count, extend, index, pop, and
3288remove
3289
3290binascii -- new functions b2a_hex and a2b_hex that convert between
3291binary data and its hex representation
3292
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003293calendar -- Many new functions that support features including control
3294over which day of the week is the first day, returning strings instead
3295of printing them. Also new symbolic constants for days of week,
3296e.g. MONDAY, ..., SUNDAY.
3297
3298cgi -- FieldStorage objects have a getvalue method that works like a
3299dictionary's get method and returns the value attribute of the object.
3300
3301ConfigParser -- The parser object has new methods has_option,
3302remove_section, remove_option, set, and write. They allow the module
3303to be used for writing config files as well as reading them.
3304
3305ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003306optionally support the RFC 959 REST command.
3307
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003308gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003309
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003310httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3311the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003312
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003313locale -- implement getdefaultlocale for Win32 and Macintosh
3314
3315marshal -- no longer dumps core when marshaling deeply nested or
3316recursive data structures
3317
3318os -- new functions isatty, seteuid, setegid, setreuid, setregid
3319
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003320os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3321support under Unix.
3322
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003323os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003324
3325os.path -- fix semantics of os.path.commonprefix
3326
3327smtplib -- support for sending very long messages
3328
3329socket -- new function getfqdn()
3330
3331readline -- new functions to read, write and truncate history files.
3332The readline section of the library reference manual contains an
3333example.
3334
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003335select -- add interface to poll system call
3336
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003337shutil -- new copyfileobj function
3338
3339SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3340HTTP server.
3341
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003342Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003343
3344urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003345e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003346
3347whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003348
3349
3350Obsolete Modules
3351----------------
3352
3353None. However note that 1.6 made a whole slew of modules obsolete:
3354stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3355poly, zmod, strop, util, whatsound.
3356
3357
3358Changed, New, Obsolete Tools
3359----------------------------
3360
Tim Peters8b092332000-09-05 20:15:25 +00003361None.
Guido van Rossume905e952000-09-05 12:42:46 +00003362
3363
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003364C-level Changes
3365---------------
3366
3367Several cleanup jobs were carried out throughout the source code.
3368
3369All C code was converted to ANSI C; we got rid of all uses of the
3370Py_PROTO() macro, which makes the header files a lot more readable.
3371
3372Most of the portability hacks were moved to a new header file,
3373pyport.h; several other new header files were added and some old
3374header files were removed, in an attempt to create a more rational set
3375of header files. (Few of these ever need to be included explicitly;
3376they are all included by Python.h.)
3377
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003378Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003379and Win64, especially for the new Intel Itanium processor. Mick also
3380added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003381
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003382The C APIs to return an object's size have been update to consistently
3383use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3384previous versions, the abstract interfaces used PyXXX_Length and the
3385concrete interfaces used PyXXX_Size. The old names,
3386e.g. PyObject_Length, are still available for backwards compatibility
3387at the API level, but are deprecated.
3388
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003389The PyOS_CheckStack function has been implemented on Windows by
3390Fredrik Lundh. It prevents Python from failing with a stack overflow
3391on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003392
3393The GC changes resulted in creation of two new slots on object,
3394tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003395the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003396
3397The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003398C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003399
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003400PyErr_Format has been updated to automatically calculate the size of
3401the buffer needed to hold the formatted result string. This change
3402prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003403
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003404New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003405
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003406PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3407that are the same as their non-Ex counterparts except they take an
3408extra flag argument that tells them to close the file when done.
3409
3410XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003411
Tim Peters8b092332000-09-05 20:15:25 +00003412
3413Windows Changes
3414---------------
3415
3416New popen2/popen3/peopen4 in os module (see Changed Modules above).
3417
3418os.popen is much more usable on Windows 95 and 98. See Microsoft
3419Knowledge Base article Q150956. The Win9x workaround described there
3420is implemented by the new w9xpopen.exe helper in the root of your
3421Python installation. Note that Python uses this internally; it is not
3422a standalone program.
3423
3424Administrator privileges are no longer required to install Python
3425on Windows NT or Windows 2000. If you have administrator privileges,
3426Python's registry info will be written under HKEY_LOCAL_MACHINE.
3427Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003428under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003429uses of Python, but will prevent some advanced uses from working
3430(for example, running a Python script as an NT service, or possibly
3431from CGI).
3432
3433[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3434installer; instead, it installs the needed Tcl/Tk files directly in the
3435Python directory. If you already have a Tcl/Tk installation, this
3436wastes some disk space (about 4 Megs) but avoids problems with
3437conflicting Tcl/Tk installations, and makes it much easier for Python
3438to ensure that Tcl/Tk can find all its files.
3439
3440[This was new in 1.6] The Windows installer now installs by default in
3441\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3442
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003443
3444Updates to the changes between 1.5.2 and 1.6
3445--------------------------------------------
3446
3447The 1.6 NEWS file can't be changed after the release is done, so here
3448is some late-breaking news:
3449
3450New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3451and changes to getlocale() and setlocale().
3452
3453The new module is now enabled per default.
3454
3455It is not true that the encodings codecs cannot be used for normal
3456strings: the string.encode() (which is also present on 8-bit strings
3457!) allows using them for 8-bit strings too, e.g. to convert files from
3458cp1252 (Windows) to latin-1 or vice-versa.
3459
3460Japanese codecs are available from Tamito KAJIYAMA:
3461http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3462
3463
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003464======================================================================