blob: bbaf2d97dd405c346c663cedf0abb8d082a63989 [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
Walter Dörwald068325e2002-04-15 13:36:47 +00009- A method zfill() was added to str and unicode, that fills a numeric
10 string to the left with zeros. For example,
11 "+123".zfill(6) -> "+00123".
12
Guido van Rossum862fe3c2002-04-15 12:36:47 +000013- Complex numbers supported divmod() and the // and % operators, but
14 these make no sense. Since this was documented, they're being
15 deprecated now.
16
Guido van Rossum49042042002-04-13 00:59:05 +000017- String methods lstrip(), rstrip() and strip() now take an optional
18 argument that specifies the characters to strip. For example,
19 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
20
Guido van Rossumc69343b2002-04-12 19:22:48 +000021- Added a new dict method pop(key). This removes and returns the
22 value corresponding to key. [SF patch #539949]
23
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000024- Changed new-style class instantiation so that when C's __new__
25 method returns something that's not a C instance, its __init__ is
26 not called. [SF bug #537450]
27
Guido van Rossum181e41a2002-04-06 00:23:25 +000028- Fixed super() to work correctly with class methods. [SF bug #535444]
29
Guido van Rossum47834462002-04-04 15:21:33 +000030- A new built-in type, bool, has been added, as well as built-in
31 names for its two values, True and False. Comparisons and sundry
32 other operations that return a truth value have been changed to
33 return a bool instead. Read PEP 285 for an explanantion of why this
34 is backward compatible.
35
Guido van Rossum95b62a62002-03-29 01:07:24 +000036- Fixed two bugs reported as SF #535905: under certain conditions,
37 deallocating a deeply nested structure could cause a segfault in the
38 garbage collector, due to interaction with the "trashcan" code;
39 access to the current frame during destruction of a local variable
40 could access a pointer to freed memory.
41
Neil Schemenauer9d50d132002-03-22 17:06:59 +000042- The optional object allocator has been enabled by default.
43
Guido van Rossum8c842552002-03-14 23:05:54 +000044- If you try to pickle an instance of a class that has __slots__ but
45 doesn't define or override __getstate__, a TypeError is now raised.
46 This is done by adding a bozo __getstate__ to the class that always
47 raises TypeError. (Before, this would appear to be pickled, but the
48 state of the slots would be lost.)
49
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000050- PyErr_Display will provide file and line information for all exceptions
51 that have an attribute print_file_and_line, not just SyntaxErrors.
52
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000053- The UTF-8 codec will now encode and decode Unicode surrogates
54 correctly and without raising exceptions for unpaired ones.
55
Neal Norwitz649b7592002-01-01 19:07:13 +000056- file.xreadlines() now raises a ValueError if the file is closed:
57 Previously, an xreadlines object was returned which would raise
58 a ValueError when the xreadlines.next() method was called.
59
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000060- posix.killpg has been added where available.
61
Neal Norwitz0c766a02002-03-27 13:03:09 +000062- sys.exit() inadvertantly allowed more than one argument.
63 An exception will now be raised if more than one argument is used.
64
Tim Petersaf8446f2001-12-21 21:36:50 +000065Extension modules
66
Martin v. Löwis06a83e92002-04-14 10:19:44 +000067- posix.mknod was added.
68
Martin v. Löwis2e64c342002-03-27 18:49:02 +000069- The locale module now exposes the C library's gettext interface.
70
Tim Petersfbf74f22002-03-14 19:06:01 +000071- A security hole ("double free") was found in zlib-1.1.3, a popular
72 third party compression library used by some Python modules. The
73 hole was quickly plugged in zlib-1.1.4, and the Windows build of
74 Python now ships with zlib-1.1.4.
75
Martin v. Löwis688357e2002-04-08 21:28:20 +000076- pwd, grp, and resource return enhanced tuples now, with symbolic
77 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000078
Martin v. Löwis99866332002-03-01 10:27:01 +000079- array.array is now a type object. A new format character
80 'u' indicates Py_UNICODE arrays. For those, .tounicode and
81 .fromunicode methods are available. Arrays now support __iadd__
82 and __imul__.
83
Neal Norwitze790eae2002-01-01 21:14:12 +000084- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000085 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
86 is called.
87
Tim Petersaf8446f2001-12-21 21:36:50 +000088Library
89
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +000090- New distutils commands for building packagers were added to
91 support pkgtool on Solaris and swinstall on HP-UX.
92
93- distutils now has a new abstract binary packager base class
94 command/bdist_packager, which simplifies writing packagers.
95 This will hopefully provide the missing bits to encourage
96 people to submit more packagers, e.g. for Debian, FreeBSD
97 and other systems.
98
Marc-André Lemburg4179a012002-04-05 12:15:05 +000099- The UTF-16, -LE and -BE now raise a NotImplementedError
100 for all calls to .readline(). Previously, they used to just
101 produce garbage or fail with an encoding error -- UTF-16 is
102 a 2-byte encoding and the C lib's line reading APIs don't
103 work well with these.
104
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000105- compileall now supports quiet operation.
106
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000107- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
108 connections.
109
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000110- socket module: the SSL support was broken out of the main
111 _socket module C helper and placed into a new _ssl helper
112 which now gets imported by socket.py if available and working.
113
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000114- encodings package: added aliases for all supported IANA character
115 sets
116
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000117- ftplib: to safeguard the user's privacy, anonymous login will use
118 "anonymous@" as default password, rather than the real user and host
119 name.
120
Fred Drake36736122002-01-10 13:50:31 +0000121- webbrowser: tightened up the command passed to os.system() so that
122 arbitrary shell code can't be executed because a bogus URL was
123 passed in.
124
Tim Peters11bd9942002-02-01 00:52:29 +0000125- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000126 gettext.find an optional all argument. Translations will now fallback
127 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000128
Martin v. Löwis9668b932002-01-12 11:27:42 +0000129- distutils bdist commands now offer a --skip-build option.
130
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000131- warnings.warn now accepts a Warning instance as first argument.
132
Fred Drakefed7e852002-04-04 19:36:15 +0000133- The xml.sax.expatreader.ExpatParser class will no longer create
134 circular references by using itself as the locator that gets passed
135 to the content handler implementation. [SF bug #535474]
136
Tim Petersaf8446f2001-12-21 21:36:50 +0000137Tools/Demos
138
Marc-André Lemburg46260092002-04-04 16:17:11 +0000139- freeze.py now produces binaries which can import shared modules,
140 unlike before when this failed due to missing symbol exports in
141 the generated binary.
142
Tim Petersaf8446f2001-12-21 21:36:50 +0000143Build
144
Martin v. Löwis1142de32002-03-29 16:28:31 +0000145- On Unix, a shared libpython2.3.so can be created with --enable-shared.
146
Tim Peters8deda702002-03-30 10:06:07 +0000147- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
148 preprocessor symbols were eliminated. The internal decisions they
149 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000150
Tim Petersaf8446f2001-12-21 21:36:50 +0000151C API
152
Neil Schemenauer9344b142002-04-12 23:00:08 +0000153- The type of tp_free has been changed from "void (*)(PyObject *)" to
154 "void (*)(void *)".
155
156- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
157
Guido van Rossum0986d822002-04-08 01:38:42 +0000158- A type can now inherit its metatype from its base type. Previously,
159 when PyType_Ready() was called, if ob_type was found to be NULL, it
160 was always set to &PyType_Type; now it is set to base->ob_type,
161 where base is tp_base, defaulting to &PyObject_Type.
162
163- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
164
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000165- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
166 functions will be allocated using pymalloc if it is enabled. These
167 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
168 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
169 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
170 PyCore_* family of APIs have been removed.
171
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000172- The "u#" parser marker will now pass through Unicode object as-is
173 without going through the buffer API.
174
Martin v. Löwis7198a522002-01-01 19:59:11 +0000175- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
176
Tim Peters10a3bb52001-12-25 19:07:38 +0000177- An old #define of ANY as void has been removed from pyport.h. This
178 hasn't been used since Python's pre-ANSI days, and the #define has
179 been marked as obsolete since then. SF bug 495548 says it created
180 conflicts with other packages, so keeping it around wasn't harmless.
181
Tim Petersaf8446f2001-12-21 21:36:50 +0000182- Because Python's magic number scheme broke on January 1st, we decided
183 to stop Python development. Thanks for all the fish!
184
Tim Petersfb05db22002-03-11 00:24:00 +0000185- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000186 scheme to a new one. See Python/import.c for details.
187
Tim Petersaf8446f2001-12-21 21:36:50 +0000188New platforms
189
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000190- GNU/Hurd is now supported.
191
Tim Petersaf8446f2001-12-21 21:36:50 +0000192Tests
193
194Windows
195
Tim Peters08e72952002-04-16 20:48:01 +0000196- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
197 of that has been fixed in the installer (disabled Wise's "delete in-
198 use files" uninstall option).
199
Guido van Rossum181e41a2002-04-06 00:23:25 +0000200- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
201
Tim Peters33187922002-04-04 20:02:04 +0000202- The installer now installs Start menu shortcuts under (the local
203 equivalent of) "All Users" when doing an Admin install.
204
Tim Petersfb05db22002-03-11 00:24:00 +0000205- file.truncate([newsize]) now works on Windows for all newsize values.
206 It used to fail if newsize didn't fit in 32 bits, reflecting a
207 limitation of MS _chsize (which is no longer used).
208
Tim Petersab034fa2002-02-01 11:27:43 +0000209- os.waitpid() is now implemented for Windows, and can be used to block
210 until a specified process exits. This is similar to, but not exactly
211 the same as, os.waitpid() on POSIX systems. If you're waiting for
212 a specific process whose pid was obtained from one of the spawn()
213 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000214 See the docs for details. The docs were changed to clarify that
215 spawn functions return, and waitpid requires, a process handle on
216 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000217
Tim Peters11bd9942002-02-01 00:52:29 +0000218- New tempfile.TemporaryFile implementation for Windows: this doesn't
219 need a TemproraryFileWrapper wrapper anymore, and should be immune
220 to a nasty problem: before 2.3, if you got a temp file on Windows, it
221 got wrapped in an object whose close() method first closed the
222 underlying file, then deleted the file. This usually worked fine.
223 However, the spawn family of functions on Windows create (at a low C
224 level) the same set of open files in the spawned process Q as were
225 open in the spawning process P. If a temp file f was among them, then
226 doing f.close() in P first closed P's C-level file handle on f, but Q's
227 C-level file handle on f remained open, so the attempt in P to delete f
228 blew up with a "Permission denied" error (Windows doesn't allow
229 deleting open files). This was surprising, subtle, and difficult to
230 work around.
231
232- The os module now exports all the symbolic constants usable with the
233 low-level os.open() on Windows: the new constants in 2.3 are
234 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
235 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
236 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
237 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
238 (so specify both if you want both; note that neither is useful unless
239 specified with O_CREAT too).
240
Tim Petersaf8446f2001-12-21 21:36:50 +0000241Mac
242
243
Tim Peters909c0912001-12-14 23:16:18 +0000244What's New in Python 2.2 final?
245Release date: 21-Dec-2001
246===============================
247
248Type/class unification and new-style classes
249
Barry Warsaw52acb492001-12-21 20:04:22 +0000250- pickle.py, cPickle: allow pickling instances of new-style classes
251 with a custom metaclass.
252
Tim Peters909c0912001-12-14 23:16:18 +0000253Core and builtins
254
Barry Warsaw52acb492001-12-21 20:04:22 +0000255- weakref proxy object: when comparing, unwrap both arguments if both
256 are proxies.
257
Tim Peters909c0912001-12-14 23:16:18 +0000258Extension modules
259
Barry Warsaw52acb492001-12-21 20:04:22 +0000260- binascii.b2a_base64(): fix a potential buffer overrun when encoding
261 very short strings.
262
263- cPickle: the obscure "fast" mode was suspected of causing stack
264 overflows on the Mac. Hopefully fixed this by setting the recursion
265 limit much smaller. If the limit is too low (it only affects
266 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
267 when compiling cPickle.c (or in pyconfig.h).
268
Tim Peters909c0912001-12-14 23:16:18 +0000269Library
270
Barry Warsaw52acb492001-12-21 20:04:22 +0000271- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
272 close or delete time).
273
274- rfc822.py: fixed a bug where the address '<>' was converted to None
275 instead of an empty string (also fixes the email.Utils module).
276
277- xmlrpclib.py: version 1.0.0; uses precision for doubles.
278
279- test suite: the pickle and cPickle tests were not executing any code
280 when run from the standard regresssion test.
281
Tim Peters909c0912001-12-14 23:16:18 +0000282Tools/Demos
283
284Build
285
286C API
287
288New platforms
289
290Tests
291
292Windows
293
Barry Warsaw52acb492001-12-21 20:04:22 +0000294- distutils package: fixed broken Windows installers (bdist_wininst).
295
296- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
297 instances are deleted at process exit time.
298
299- socket.py: prevent mysterious warnings when socket instances are
300 deleted at process exit time.
301
302- posixmodule.c: fix a Windows crash with stat() of a filename ending
303 in backslash.
304
Tim Peters909c0912001-12-14 23:16:18 +0000305Mac
306
Barry Warsaw52acb492001-12-21 20:04:22 +0000307- The Carbon toolbox modules have been upgraded to Universal Headers
308 3.4, and experimental CoreGraphics and CarbonEvents modules have
309 been added. All only for framework-enabled MacOSX.
310
Tim Peters909c0912001-12-14 23:16:18 +0000311
Tim Peters6272dfd2001-12-13 19:34:00 +0000312What's New in Python 2.2c1?
313Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000314===========================
315
316Type/class unification and new-style classes
317
Barry Warsaw06557452001-12-14 20:47:12 +0000318- Guido's tutorial introduction to the new type/class features has
319 been extensively updated. See
320
321 http://www.python.org/2.2/descrintro.html
322
323 That remains the primary documentation in this area.
324
Guido van Rossum33bab012001-12-05 22:45:48 +0000325- Fixed a leak: instance variables declared with __slots__ were never
326 deleted!
327
Guido van Rossum4b800852001-12-03 00:54:52 +0000328- The "delete attribute" method of descriptor objects is called
329 __delete__, not __del__. In previous releases, it was mistakenly
330 called __del__, which created an unfortunate overloading condition
331 with finalizers. (The "get attribute" and "set attribute" methods
332 are still called __get__ and __set__, respectively.)
333
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000334- Some subtle issues with the super built-in were fixed:
335
336 (a) When super itself is subclassed, its __get__ method would still
337 return an instance of the base class (i.e., of super).
338
339 (b) super(C, C()).__class__ would return C rather than super. This
340 is confusing. To fix this, I decided to change the semantics of
341 super so that it only applies to code attributes, not to data
342 attributes. After all, overriding data attributes is not
343 supported anyway.
344
345 (c) The __get__ method didn't check whether the argument was an
346 instance of the type used in creation of the super instance.
347
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000348- Previously, hash() of an instance of a subclass of a mutable type
349 (list or dictionary) would return some value, rather than raising
350 TypeError. This has been fixed. Also, directly calling
351 dict.__hash__ and list.__hash__ now raises the same TypeError
352 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000353
Guido van Rossumd331cb52001-12-05 19:46:42 +0000354- New-style objects now support deleting their __dict__. This is for
355 all intents and purposes equivalent to assigning a brand new empty
356 dictionary, but saves space if the object is not used further.
357
Tim Petersb3c9af12001-11-17 00:21:57 +0000358Core and builtins
359
Tim Peters3caca232001-12-06 06:23:26 +0000360- -Qnew now works as documented in PEP 238: when -Qnew is passed on
361 the command line, all occurrences of "/" use true division instead
362 of classic division. See the PEP for details. Note that "all"
363 means all instances in library and 3rd-party modules, as well as in
364 your own code. As the PEP says, -Qnew is intended for use only in
365 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000366 Note that test_coercion.py in the standard Python test suite fails
367 under -Qnew; this is expected, and won't be repaired until true
368 division becomes the default (in the meantime, test_coercion is
369 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000370
Fred Drake6c01e252001-12-14 17:08:12 +0000371- complex() now only allows the first argument to be a string
372 argument, and raises TypeError if either the second arg is a string
373 or if the second arg is specified when the first is a string.
374
Tim Petersb3c9af12001-11-17 00:21:57 +0000375Extension modules
376
Martin v. Löwis560da622001-11-24 09:24:51 +0000377- gc.get_referents was renamed to gc.get_referrers.
378
Tim Petersb3c9af12001-11-17 00:21:57 +0000379Library
380
Tim Peters25059d32001-12-07 20:35:43 +0000381- Functions in the os.spawn() family now release the global interpreter
382 lock around calling the platform spawn. They should always have done
383 this, but did not before 2.2c1. Multithreaded programs calling
384 an os.spawn function with P_WAIT will no longer block all Python threads
385 until the spawned program completes. It's possible that some programs
386 relies on blocking, although more likely by accident than by design.
387
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000388- webbrowser defaults to netscape.exe on OS/2 now.
389
Martin v. Löwis652e1912001-11-25 14:50:56 +0000390- Tix.ResizeHandle exposes detach_widget, hide, and show.
391
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000392- The charset alias windows_1252 has been added.
393
Barry Warsaw06557452001-12-14 20:47:12 +0000394- types.StringTypes is a tuple containing the defined string types;
395 usually this will be (str, unicode), but if Python was compiled
396 without Unicode support it will be just (str,).
397
398- The pulldom and minidom modules were synchronized to PyXML.
399
Tim Petersb3c9af12001-11-17 00:21:57 +0000400Tools/Demos
401
Barry Warsaw06557452001-12-14 20:47:12 +0000402- A new script called Tools/scripts/google.py was added, which fires
403 off a search on Google.
404
Tim Petersb3c9af12001-11-17 00:21:57 +0000405Build
406
Barry Warsaw06557452001-12-14 20:47:12 +0000407- Note that release builds of Python should arrange to define the
408 preprocessor symbol NDEBUG on the command line (or equivalent).
409 In the 2.2 pre-release series we tried to define this by magic in
410 Python.h instead, but it proved to cause problems for extension
411 authors. The Unix, Windows and Mac builds now all define NDEBUG in
412 release builds via cmdline (or equivalent) instead. Ports to
413 other platforms should do likewise.
414
Jack Jansen1999ef42001-12-06 21:47:20 +0000415- It is no longer necessary to use --with-suffix when building on a
416 case-insensitive file system (such as Mac OS X HFS+). In the build
417 directory an extension is used, but not in the installed python.
418
Tim Petersb3c9af12001-11-17 00:21:57 +0000419C API
420
Tim Petersf582b822001-12-11 18:51:08 +0000421- New function PyDict_MergeFromSeq2() exposes the builtin dict
422 constructor's logic for updating a dictionary from an iterable object
423 producing key-value pairs.
424
Tim Peterscffed4b2001-11-29 03:26:37 +0000425- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000426 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000427 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
428 dump core in some bad cases. This has been repaired. As a result,
429 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
430 previously went unchallenged.
431
Tim Petersb3c9af12001-11-17 00:21:57 +0000432New platforms
433
434Tests
435
436Windows
437
438Mac
439
Jack Jansenffa260f2001-12-06 21:14:00 +0000440- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
441 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000442
Barry Warsaw06557452001-12-14 20:47:12 +0000443- Changed logic for finding python home in Mac OS X framework Pythons.
444 Now sys.executable points to the executable again, in stead of to
445 the shared library. The latter is used only for locating the python
446 home.
447
448
Tim Peters84362bc2001-10-19 17:55:30 +0000449What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000450Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000451===========================
452
453Type/class unification and new-style classes
454
Guido van Rossum3d27df02001-11-15 20:27:54 +0000455- Multiple inheritance mixing new-style and classic classes in the
456 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000457
458 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000459 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000460
461 The MRO (method resolution order) for each base class is respected
462 according to its kind, but the MRO for the derived class is computed
463 using new-style MRO rules if any base clase is a new-style class.
464 This needs to be documented.
465
Tim Petersa427a2b2001-10-29 22:25:45 +0000466- The new builtin dictionary() constructor, and dictionary type, have
467 been renamed to dict. This reflects a decade of common usage.
468
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000469- dict() now accepts an iterable object producing 2-sequences. For
470 example, dict(d.items()) == d for any dictionary d. The argument,
471 and the elements of the argument, can be any iterable objects.
472
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000473- New-style classes can now have a __del__ method, which is called
474 when the instance is deleted (just like for classic classes).
475
Guido van Rossum12d955c2001-10-26 14:56:06 +0000476- Assignment to object.__dict__ is now possible, for objects that are
477 instances of new-style classes that have a __dict__ (unless the base
478 class forbids it).
479
Guido van Rossumc8e56452001-10-22 00:43:43 +0000480- Methods of built-in types now properly check for keyword arguments
481 (formerly these were silently ignored). The only built-in methods
482 that take keyword arguments are __call__, __init__ and __new__.
483
Guido van Rossum86443212001-10-27 22:28:54 +0000484- The socket function has been converted to a type; see below.
485
Tim Peters84362bc2001-10-19 17:55:30 +0000486Core and builtins
487
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000488- Assignment to __debug__ raises SyntaxError at compile-time. This
489 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000490 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000491
Guido van Rossum12d955c2001-10-26 14:56:06 +0000492- Clarified the error messages for unsupported operands to an operator
493 (like 1 + '').
494
Tim Peters84362bc2001-10-19 17:55:30 +0000495Extension modules
496
Tim Peters5ebfd362001-11-13 23:11:19 +0000497- mmap has a new keyword argument, "access", allowing a uniform way for
498 both Windows and Unix users to create read-only, write-through and
499 copy-on-write memory mappings. This was previously possible only on
500 Unix. A new keyword argument was required to support this in a
501 uniform way because the mmap() signuatures had diverged across
502 platforms. Thanks to Jay T Miller for repairing this!
503
Tim Peters169ded02001-11-03 19:57:21 +0000504- By default, the gc.garbage list now contains only those instances in
505 unreachable cycles that have __del__ methods; in 2.1 it contained all
506 instances in unreachable cycles. "Instances" here has been generalized
507 to include instances of both new-style and old-style classes.
508
Guido van Rossum12d955c2001-10-26 14:56:06 +0000509- The socket module defines a new method for socket objects,
510 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000511 send() until all data has been sent. Also, the socket function has
512 been converted to a subclassable type, like list and tuple (etc.)
513 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000514
515- Various bugfixes to the curses module. There is now a test suite
516 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000517
Guido van Rossum692adf12001-10-30 03:03:03 +0000518- binascii.b2a_base64 no longer places an arbitrary restriction of 57
519 bytes on its input.
520
Tim Peters84362bc2001-10-19 17:55:30 +0000521Library
522
Tim Peters5ebfd362001-11-13 23:11:19 +0000523- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000524 convenience function.
525
Tim Peters75335872001-11-03 19:35:43 +0000526- Symbolic group names in regular expressions must be unique. For
527 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
528 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000529 Python 2.2 detects this error at regexp compilation time;
530 previously, the error went undetected, and results were
531 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
532 pattern.subn() methods have been rewritten in C. Also, an
533 experimental function/method finditer() has been added, which works
534 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000535
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000536- Tix exposes more commands through the classes DirSelectBox,
537 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
538 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
539 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
540
Tim Peters98791af2001-10-23 01:59:54 +0000541- Traceback objects are now scanned by cyclic garbage collection, so
542 cycles created by casual use of sys.exc_info() no longer cause
543 permanent memory leaks (provided garbage collection is enabled).
544
Guido van Rossum49192142001-10-24 20:51:44 +0000545- os.extsep -- a new variable needed by the RISCOS support. It is the
546 separator used by extensions, and is '.' on all platforms except
547 RISCOS, where it is '/'. There is no need to use this variable
548 unless you have a masochistic desire to port your code to RISCOS.
549
Barry Warsaw012852b2001-11-16 16:17:27 +0000550- mimetypes.py has optional support for non-standard, but commonly
551 found types. guess_type() and guess_extension() now accept an
552 optional `strict' flag, defaulting to true, which controls whether
553 recognize non-standard types or not. A few non-standard types we
554 know about have been added. Also, when run as a script, there are
555 new -l and -e options.
556
557- statcache is now deprecated.
558
559- email.Utils.formatdate() now produces the preferred RFC 2822 style
560 dates with numeric timezones (it used to produce obsolete dates
561 hard coded to "GMT" timezone). An optional `localtime' flag is
562 added to produce dates in the local timezone, with daylight savings
563 time properly taken into account.
564
565- In pickle and cPickle, instead of masking errors in load() by
566 transforming them into SystemError, we let the original exception
567 propagate out. Also, implement support for __safe_for_unpickling__
568 in pickle, as it already was supported in cPickle.
569
Tim Peters84362bc2001-10-19 17:55:30 +0000570Tools/Demos
571
572Build
573
Barry Warsaw012852b2001-11-16 16:17:27 +0000574- The dbm module is built using libdb1 if available. The bsddb module
575 is built with libdb3 if available.
576
577- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
578
Tim Peters84362bc2001-10-19 17:55:30 +0000579C API
580
Tim Peters1fc240e2001-10-26 05:06:50 +0000581- New function PySequence_Fast_GET_SIZE() returns the size of a non-
582 NULL result from PySequence_Fast(), more quickly than calling
583 PySequence_Size().
584
Barry Warsaw012852b2001-11-16 16:17:27 +0000585- New argument unpacking function PyArg_UnpackTuple() added.
586
587- New functions PyObject_CallFunctionObjArgs() and
588 PyObject_CallMethodObjArgs() have been added to make it more
589 convenient and efficient to call functions and methods from C.
590
591- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
592 possible that this will propagate errors it didn't before.
593
594- New function PyObject_CheckReadBuffer(), which returns true if its
595 argument supports the single-segment readable buffer interface.
596
Tim Peters84362bc2001-10-19 17:55:30 +0000597New platforms
598
Guido van Rossum86443212001-10-27 22:28:54 +0000599- We've finally confirmed that this release builds on HP-UX 11.00,
600 *with* threads, and passes the test suite.
601
Tim Peters7a33d8b2001-11-05 02:51:07 +0000602- Thanks to a series of patches from Michael Muller, Python may build
603 again under OS/2 Visual Age C++.
604
Guido van Rossum49192142001-10-24 20:51:44 +0000605- Updated RISCOS port by Dietmar Schwertberger.
606
Tim Peters84362bc2001-10-19 17:55:30 +0000607Tests
608
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000609- Added a test script for the curses module. It isn't run automatically;
610 regrtest.py must be run with '-u curses' to enable it.
611
Tim Peters84362bc2001-10-19 17:55:30 +0000612Windows
613
Barry Warsaw012852b2001-11-16 16:17:27 +0000614Mac
615
616- PythonScript has been moved to unsupported and is slated to be
617 removed completely in the next release.
618
619- It should now be possible to build applets that work on both OS9 and
620 OSX.
621
622- The core is now linked with CoreServices not Carbon; as a side
623 result, default 8bit encoding on OSX is now ASCII.
624
625- Python should now build on OSX 10.1.1
626
Tim Peters84362bc2001-10-19 17:55:30 +0000627
Tim Petersabf925f2001-09-28 21:53:42 +0000628What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000629Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000630===========================
631
632Type/class unification and new-style classes
633
Guido van Rossum687ae002001-10-15 22:03:32 +0000634- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000635 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000636 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000637 remains: the __dict__ of a new-style class is a read-only proxy; you
638 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000639 __defined__ attribute of new-style types no longer exists, for lack
640 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000641 future a __cache__ may be resurrected with a similar function, if I
642 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000643
Tim Peters1c9ca872001-10-04 06:43:12 +0000644- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
645 always returned None, even when there was a class docstring).
646
647- doctest now finds and runs docstrings attached to new-style classes,
648 class methods, static methods, and properties.
649
Guido van Rossum9074ef62001-10-16 21:34:49 +0000650Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000651
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000652- A very subtle syntactical pitfall in list comprehensions was fixed.
653 For example: [a+b for a in 'abc', for b in 'def']. The comma in
654 this example is a mistake. Previously, this would silently let 'a'
655 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
656 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
657 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
658 Note that [a for a in <singleton>] is a convoluted way to say
659 [<singleton>] anyway, so it's not like any expressiveness is lost.
660
Guido van Rossum9074ef62001-10-16 21:34:49 +0000661- getattr(obj, name, default) now only catches AttributeError, as
662 documented, rather than returning the default value for all
663 exceptions (which could mask bugs in a __getattr__ hook, for
664 example).
665
Fred Drakecb7a6b52001-10-22 18:41:51 +0000666- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000667 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000668 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000669 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000670
Guido van Rossum1c486092001-10-19 02:05:35 +0000671- unicode(obj) now behaves more like str(obj), accepting arbitrary
672 objects, and calling a __unicode__ method if it exists.
673 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000674 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000675
Barry Warsawf6fb1712001-10-19 05:35:40 +0000676- isinstance() now allows any object as the first argument and a
677 class, a type or something with a __bases__ tuple attribute for the
678 second argument. The second argument may also be a tuple of a
679 class, type, or something with __bases__, in which case isinstance()
680 will return true if the first argument is an instance of any of the
681 things contained in the second argument tuple. E.g.
682
683 isinstance(x, (A, B))
684
685 returns true if x is an instance of A or B.
686
Guido van Rossum9074ef62001-10-16 21:34:49 +0000687Extension modules
688
689- thread.start_new_thread() now returns the thread ID (previously None).
690
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000691- binascii has now two quopri support functions, a2b_qp and b2a_qp.
692
Guido van Rossumc524d952001-10-19 01:31:59 +0000693- readline now supports setting the startup_hook and the
694 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000695
Guido van Rossumc524d952001-10-19 01:31:59 +0000696- os and posix supports chroot(), setgroups() and unsetenv() where
697 available. The stat(), fstat(), statvfs() and fstatvfs() functions
698 now return "pseudo-sequences" -- the various fields can now be
699 accessed as attributes (e.g. os.stat("/").st_mtime) but for
700 backwards compatibility they also behave as a fixed-length sequence.
701 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000702 attributes.
703
704- time: localtime(), gmtime() and strptime() now return a
705 pseudo-sequence similar to the os.stat() return value, with
706 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000707
Guido van Rossum9074ef62001-10-16 21:34:49 +0000708- Decompression objects in the zlib module now accept an optional
709 second parameter to decompress() that specifies the maximum amount
710 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000711
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000712- optional SSL support in the socket module now exports OpenSSL
713 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
714 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000715 automatically seed its PRNG. Also, the keyfile and certfile
716 arguments to socket.ssl() are now optional.
717
718- posixmodule (and by extension, the os module on POSIX platforms) now
719 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000720
Guido van Rossum9074ef62001-10-16 21:34:49 +0000721Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000722
Tim Peters7402f792001-10-02 03:53:41 +0000723- doctest now excludes functions and classes not defined by the module
724 being tested, thanks to Tim Hochberg.
725
Fred Drakecb7a6b52001-10-22 18:41:51 +0000726- HotShot, a new profiler implemented using a C-based callback, has
727 been added. This substantially reduces the overhead of profiling,
728 but it is still quite preliminary. Support modules and
729 documentation will be added in upcoming releases (before 2.2 final).
730
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000731- profile now produces correct output in situations where an exception
732 raised in Python is cleared by C code (e.g. hasattr()). This used
733 to cause wrong output, including spurious claims of recursive
734 functions and attribution of time spent to the wrong function.
735
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000736 The code and documentation for the derived OldProfile and HotProfile
737 profiling classes was removed. The code hasn't worked for years (if
738 you tried to use them, they raised exceptions). OldProfile
739 intended to reproduce the behavior of the profiler Python used more
740 than 7 years ago, and isn't interesting anymore. HotProfile intended
741 to provide a faster profiler (but producing less information), and
742 that's a worthy goal we intend to meet via a different approach (but
743 without losing information).
744
Tim Peterscce092d2001-10-09 05:31:56 +0000745- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000746 a much better system-specific calibration constant. The constant can
747 now be specified in an instance constructor, or as a Profile class or
748 instance variable, instead of by editing profile.py's source code.
749 Calibration must still be done manually (see the docs for the profile
750 module).
751
752 Note that Profile.calibrate() must be overriden by subclasses.
753 Improving the accuracy required exploiting detailed knowledge of
754 profiler internals; the earlier method abstracted away the details
755 and measured a simplified model instead, but consequently computed
756 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000757
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000758- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000759 which indicates whether output is intended for the header 'Q'
760 encoding.
761
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000762- The SocketServer.ThreadingMixIn class now closes the request after
763 finish_request() returns. (Not when it errors out though.)
764
Barry Warsawf6fb1712001-10-19 05:35:40 +0000765- The nntplib module's NNTP.body() method has grown a `file' argument
766 to allow saving the message body to a file.
767
768- The email package has added a class email.Parser.HeaderParser which
769 only parses headers and does not recurse into the message's body.
770 Also, the module/class MIMEAudio has been added for representing
771 audio data (contributed by Anthony Baxter).
772
773- ftplib should be able to handle files > 2GB.
774
775- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
776 ON, and OFF.
777
Fred Drakecb7a6b52001-10-22 18:41:51 +0000778- xml.dom.minidom NodeList objects now support the length attribute
779 and item() method as required by the DOM specifications.
780
Guido van Rossumed554f62001-10-02 23:15:37 +0000781Tools/Demos
782
783- Demo/dns was removed. It no longer serves any purpose; a package
784 derived from it is now maintained by Anthony Baxter, see
785 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000786
Barry Warsawf6fb1712001-10-19 05:35:40 +0000787- The freeze tool has been made more robust, and two new options have
788 been added: -X and -E.
789
Tim Petersabf925f2001-09-28 21:53:42 +0000790Build
791
Barry Warsawf6fb1712001-10-19 05:35:40 +0000792- configure will use CXX in LINKCC if CXX is used to build main() and
793 the system requires to link a C++ main using the C++ compiler.
794
Tim Petersabf925f2001-09-28 21:53:42 +0000795C API
796
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000797- The documentation for the tp_compare slot is updated to require that
798 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
799 not correct. This is not yet enforced but will be enforced in
800 Python 2.3; even later, we may use -2 to indicate errors and +2 for
801 "NotImplemented". Right now, -1 should be used for an error return.
802
Tim Petersd38b1c72001-09-30 05:09:37 +0000803- PyLong_AsLongLong() now accepts int (as well as long) arguments.
804 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
805 as long) arguments.
806
Guido van Rossum3c288632001-10-16 21:13:49 +0000807- PyThread_start_new_thread() now returns a long int giving the thread
808 ID, if one can be calculated; it returns -1 for error, 0 if no
809 thread ID is calculated (this is an incompatible change, but only
810 the thread module used this API). This code has only really been
811 tested on Linux and Windows; other platforms please beware (and
812 report any bugs or strange behavior).
813
Guido van Rossum1c486092001-10-19 02:05:35 +0000814- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
815 input.
816
Tim Petersabf925f2001-09-28 21:53:42 +0000817New platforms
818
819Tests
820
821Windows
822
Tim Peters04cf1d32001-10-09 22:39:40 +0000823- Installer: If you install IDLE, and don't disable file-extension
824 registration, a new "Edit with IDLE" context (right-click) menu entry
825 is created for .py and .pyw files.
826
Tim Peters1ce3cf72001-10-01 17:58:40 +0000827- The signal module now supports SIGBREAK on Windows, thanks to Steven
828 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
829 action remains to call Win32 ExitProcess(). This can be changed via
830 signal.signal(). For example:
831
832 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
833 # (SIGINT) behavior.
834 import signal
835 signal.signal(signal.SIGBREAK,
836 signal.default_int_handler)
837
838 try:
839 while 1:
840 pass
841 except KeyboardInterrupt:
842 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
843 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
844 # program without the possibility for any Python-level cleanup).
845 print "Clean exit"
846
Tim Petersabf925f2001-09-28 21:53:42 +0000847
Tim Petersb07352e2001-09-08 01:25:47 +0000848What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000849Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000850===========================
851
Guido van Rossum808eea72001-09-25 04:15:41 +0000852Type/class unification and new-style classes
853
854- pydoc and inspect are now aware of new-style classes;
855 e.g. help(list) at the interactive prompt now shows proper
856 documentation for all operations on list objects.
857
858- Applications using Jim Fulton's ExtensionClass module can now safely
859 be used with Python 2.2. In particular, Zope 2.4.1 now works with
860 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
861 examples also work again. It is hoped that Gtk and Boost also work
862 with 2.2a4 and beyond. (If you can confirm this, please write
863 webmaster@python.org; if there are still problems, please open a bug
864 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000865
Tim Peters66c1a522001-09-24 21:17:50 +0000866- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
867 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
868 in the constructed property object. fget, fset and fdel weren't
869 discoverable from Python in 2.2a3. __doc__ is new, and allows to
870 associate a docstring with a property.
871
Guido van Rossum808eea72001-09-25 04:15:41 +0000872- Comparison overloading is now more completely implemented. For
873 example, a str subclass instance can properly be compared to a str
874 instance, and it can properly overload comparison. Ditto for most
875 other built-in object types.
876
877- The repr() of new-style classes has changed; instead of <type
878 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
879 *except* for built-in types, which are still rendered as <type
880 'Foo'> (to avoid upsetting existing code that might parse or
881 otherwise rely on repr() of certain type objects).
882
883- The repr() of new-style objects is now always <Foo object at XXX>;
884 previously, it was sometimes <Foo instance at XXX>.
885
886- For new-style classes, what was previously called __getattr__ is now
887 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000888 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000889 one in classic classes is defined which is called only if regular
890 attribute access raises AttributeError; to catch *all* attribute
891 access, you can use __getattribute__ (for new-style classes). If
892 both are defined, __getattribute__ is called first, and if it raises
893 AttributeError, __getattr__ is called.
894
895- The __class__ attribute of new-style objects can be assigned to.
896 The new class must have the same C-level object layout as the old
897 class.
898
899- The builtin file type can be subclassed now. In the usual pattern,
900 "file" is the name of the builtin type, and file() is a new builtin
901 constructor, with the same signature as the builtin open() function.
902 file() is now the preferred way to open a file.
903
904- Previously, __new__ would only see sequential arguments passed to
905 the type in a constructor call; __init__ would see both sequential
906 and keyword arguments. This made no sense whatsoever any more, so
907 now both __new__ and __init__ see all arguments.
908
909- Previously, hash() applied to an instance of a subclass of str or
910 unicode always returned 0. This has been repaired.
911
912- Previously, an operation on an instance of a subclass of an
913 immutable type (int, long, float, complex, tuple, str, unicode),
914 where the subtype didn't override the operation (and so the
915 operation was handled by the builtin type), could return that
916 instance instead a value of the base type. For example, if s was of
917 a str sublass type, s[:] returned s as-is. Now it returns a str
918 with the same value as s.
919
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000920- Provisional support for pickling new-style objects has been added.
921
Guido van Rossum808eea72001-09-25 04:15:41 +0000922Core
923
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000924- file.writelines() now accepts any iterable object producing strings.
925
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000926- PyUnicode_FromEncodedObject() now works very much like
927 PyObject_Str(obj) in that it tries to use __str__/tp_str
928 on the object if the object is not a string or buffer. This
929 makes unicode() behave like str() when applied to non-string/buffer
930 objects.
931
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000932- PyFile_WriteObject now passes Unicode objects to the file's write
933 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000934 of a print statement must support Unicode objects, i.e. they must
935 at least convert them into ASCII strings.
936
Guido van Rossum624c8af2001-09-18 15:21:04 +0000937- Thread scheduling on Solaris should be improved; it is no longer
938 necessary to insert a small sleep at the start of a thread in order
939 to let other runnable threads be scheduled.
940
Tim Petersb07352e2001-09-08 01:25:47 +0000941Library
942
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000943- StringIO.StringIO instances and cStringIO.StringIO instances support
944 read character buffer compatible objects for their .write() methods.
945 These objects are converted to strings and then handled as such
946 by the instances.
947
Barry Warsaw2f600732001-09-24 04:28:10 +0000948- The "email" package has been added. This is basically a port of the
949 mimelib package <http://sf.net/projects/mimelib> with API changes
950 and some implementations updated to use iterators and generators.
951
Tim Peters8a9c2842001-09-22 21:30:22 +0000952- difflib.ndiff() and difflib.Differ.compare() are generators now. This
953 restores the ability of Tools/scripts/ndiff.py to start producing output
954 before the entire comparison is complete.
955
Barry Warsaw58b072d2001-09-22 04:44:21 +0000956- StringIO.StringIO instances and cStringIO.StringIO instances support
957 iteration just like file objects (i.e. their .readline() method is
958 called for each iteration until it returns an empty string).
959
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000960- The codecs module has grown four new helper APIs to access
961 builtin codecs: getencoder(), getdecoder(), getreader(),
962 getwriter().
963
Guido van Rossum624c8af2001-09-18 15:21:04 +0000964- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
965 simplifies writing XML RPC servers.
966
Barry Warsaw647d5e82001-09-28 17:01:02 +0000967- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000968 after interpretation of symbolic links. On non-Unix systems, this
969 is an alias for os.path.abspath().
970
Tim Peters16a77ad2001-09-08 04:00:12 +0000971- operator.indexOf() (PySequence_Index() in the C API) now works with any
972 iterable object.
973
Guido van Rossum624c8af2001-09-18 15:21:04 +0000974- smtplib now supports various authentication and security features of
975 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000976
Guido van Rossum624c8af2001-09-18 15:21:04 +0000977- hmac: a new module implementing keyed hashing for message
978 authentication.
979
980- mimetypes now recognizes more extensions and file types. At the
981 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000982
Guido van Rossum624c8af2001-09-18 15:21:04 +0000983- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000984 Python 2.2 bytecode generation. It has also been promoted from a
985 Tool to a standard library package. (Tools/compiler still exists as
986 a sample driver.)
987
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000988Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000989
Tim Petersb07352e2001-09-08 01:25:47 +0000990Build
991
Guido van Rossum624c8af2001-09-18 15:21:04 +0000992- Large file support (LFS) is now automatic when the platform supports
993 it; no more manual configuration tweaks are needed. On Linux, at
994 least, it's possible to have a system whose C library supports large
995 files but whose kernel doesn't; in this case, large file support is
996 still enabled but doesn't do you any good unless you upgrade your
997 kernel or share your Python executable with another system whose
998 kernel has large file support.
999
1000- The configure script now supplies plausible defaults in a
1001 cross-compilation environment. This doesn't mean that the supplied
1002 values are always correct, or that cross-compilation now works
1003 flawlessly -- but it's a first step (and it shuts up most of
1004 autoconf's warnings about AC_TRY_RUN).
1005
1006- The Unix build is now a bit less chatty, courtesy of the parser
1007 generator. The build is completely silent (except for errors) when
1008 using "make -s", thanks to a -q option to setup.py.
1009
Tim Petersb07352e2001-09-08 01:25:47 +00001010C API
1011
Guido van Rossum624c8af2001-09-18 15:21:04 +00001012- The "structmember" API now supports some new flag bits to deny read
1013 and/or write access to attributes in restricted execution mode.
1014
Tim Petersb07352e2001-09-08 01:25:47 +00001015New platforms
1016
Guido van Rossum624c8af2001-09-18 15:21:04 +00001017- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1018 (http://familiar.handhelds.org).
1019
Tim Petersb07352e2001-09-08 01:25:47 +00001020Tests
1021
Tim Peters8a9c2842001-09-22 21:30:22 +00001022- The "classic" standard tests, which work by comparing stdout to
1023 an expected-output file under Lib/test/output/, no longer stop at
1024 the first mismatch. Instead the test is run to completion, and a
1025 variant of ndiff-style comparison is used to report all differences.
1026 This is much easier to understand than the previous style of reporting.
1027
1028- The unittest-based standard tests now use regrtest's test_main()
1029 convention, instead of running as a side-effect of merely being
1030 imported. This allows these tests to be run in more natural and
1031 flexible ways as unittests, outside the regrtest framework.
1032
1033- regrtest.py is much better integrated with unittest and doctest now,
1034 especially in regard to reporting errors.
1035
Tim Petersb07352e2001-09-08 01:25:47 +00001036Windows
1037
Guido van Rossum624c8af2001-09-18 15:21:04 +00001038- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001039 that support it (NTFS under Windows 2000). See "What's New in
1040 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001041
Tim Petersb07352e2001-09-08 01:25:47 +00001042
Tim Petersedc99312001-08-22 21:36:50 +00001043What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001044Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001045===========================
1046
1047Core
1048
Tim Peters9fffa3e2001-09-04 05:14:19 +00001049- Conversion of long to float now raises OverflowError if the long is too
1050 big to represent as a C double.
1051
Tim Peters32f453e2001-09-03 08:35:41 +00001052- The 3-argument builtin pow() no longer allows a third non-None argument
1053 if either of the first two arguments is a float, or if both are of
1054 integer types and the second argument is negative (in which latter case
1055 the arguments are converted to float, so this is really the same
1056 restriction).
1057
Tim Peters5d2b77c2001-09-03 05:47:38 +00001058- The builtin dir() now returns more information, and sometimes much
1059 more, generally naming all attributes of an object, and all attributes
1060 reachable from the object via its class, and from its class's base
1061 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1062 an empty list. In 2.2a3,
1063
1064 >>> dir([])
1065 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1066 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1067 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1068 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1069 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1070 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1071 'reverse', 'sort']
1072
1073 dir(module) continues to return only the module's attributes, though.
1074
Tim Petersbdee63f2001-09-02 03:40:59 +00001075- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001076 than raising OverflowError. This is a partial implementation of PEP
1077 237. You can use -Wdefault::OverflowWarning to enable a warning for
1078 this situation, and -Werror::OverflowWarning to revert to the old
1079 OverflowError exception.
1080
Guido van Rossum61c345f2001-09-04 03:26:15 +00001081- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001082 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001083 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1084 -Qold, meaning the / operator has its classic meaning and no
1085 warnings are issued. Using -Qwarn issues a run-time warning about
1086 all uses of classic division for int and long arguments; -Qwarnall
1087 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001088 (for use with fixdiv.py).
1089 [Note: the remainder of this paragraph (preserved below) became
1090 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1091 <obsolete>
1092 Using -Qnew is questionable; it turns on new division by default, but
1093 only in the __main__ module. You can usefully combine -Qwarn or
1094 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1095 warns about classic division everywhere else.
1096 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001097
Tim Petersbdee63f2001-09-02 03:40:59 +00001098- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001099 long, float, str, unicode, and tuple. (The types complex, list and
1100 dictionary can also be subclassed; this was introduced earlier.)
1101 Note that restrictions apply when subclassing immutable built-in
1102 types: you can only affect the value of the instance by overloading
1103 __new__. You can add mutable attributes, and the subclass instances
1104 will have a __dict__ attribute, but you cannot change the "value"
1105 (as implemented by the base class) of an immutable subclass instance
1106 once it is created.
1107
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001108- The dictionary constructor now takes an optional argument, a
1109 mapping-like object, and initializes the dictionary from its
1110 (key, value) pairs.
1111
Tim Petersbdee63f2001-09-02 03:40:59 +00001112- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001113 "cooperative super calls" in a multiple inheritance setting. For an
1114 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1115
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001116- A new built-in type, property, has been added. This enables the
1117 creation of "properties". These are attributes implemented by
1118 getter and setter functions (or only one of these for read-only or
1119 write-only attributes), without the need to override __getattr__.
1120 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001121
Tim Petersbdee63f2001-09-02 03:40:59 +00001122- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001123 liberalized, to allow leading zeroes. Examples of literals now
1124 legal that were SyntaxErrors before:
1125
1126 00.0 0e3 0100j 07.5 00000000000000000008.
1127
Tim Petersbdee63f2001-09-02 03:40:59 +00001128- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001129 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1130
Tim Petersedc99312001-08-22 21:36:50 +00001131Library
1132
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001133- telnetlib includes symbolic names for the options, and support for
1134 setting an option negotiation callback.
1135
Tim Petersa40c7932001-09-05 22:36:56 +00001136- The new C standard no longer requires that math libraries set errno to
1137 ERANGE on overflow. For platform libraries that exploit this new
1138 freedom, Python's overflow-checking was wholly broken. A new overflow-
1139 checking scheme attempts to repair that, but may not be reliable on all
1140 platforms (C doesn't seem to provide anything both useful and portable
1141 in this area anymore).
1142
Martin v. Löwis44f86962001-09-05 13:44:54 +00001143- Asynchronous timeout actions are available through the new class
1144 threading.Timer.
1145
Tim Peters78526162001-09-05 00:53:45 +00001146- math.log and math.log10 now return sensible results for even huge
1147 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1148
Tim Petersbdee63f2001-09-02 03:40:59 +00001149- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001150 currently held. See the docs for the imp module.
1151
Tim Petersbdee63f2001-09-02 03:40:59 +00001152- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001153 dumps containing ints written on platforms where Python ints are 8 bytes.
1154 When read on a box where Python ints are 4 bytes, such values are
1155 converted to Python longs.
1156
Tim Petersbdee63f2001-09-02 03:40:59 +00001157- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001158 code objects is no longer allowed. This plugs a security hole.
1159
Steve Purcell6091cd62001-09-06 16:05:17 +00001160- unittest.TestResult instances no longer store references to tracebacks
1161 generated by test failures. This prevents unexpected dangling references
1162 to objects that should be garbage collected between tests.
1163
Tim Petersedc99312001-08-22 21:36:50 +00001164Tools
1165
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001166- Tools/scripts/fixdiv.py has been added which can be used to fix
1167 division operators as per PEP 238.
1168
Tim Petersedc99312001-08-22 21:36:50 +00001169Build
1170
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001171- If you are an adventurous person using Mac OS X you may want to look at
1172 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1173 application, which can be used for experimenting with Carbon or Cocoa.
1174 Discussion of this on pythonmac-sig, please.
1175
Tim Peters7eea37e2001-09-04 22:08:56 +00001176C API
1177
1178- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001179
Tim Peters9fffa3e2001-09-04 05:14:19 +00001180- Note that PyLong_AsDouble can fail! This has always been true, but no
1181 callers checked for it. It's more likely to fail now, because overflow
1182 errors are properly detected now. The proper way to check:
1183
1184 double x = PyLong_AsDouble(some_long_object);
1185 if (x == -1.0 && PyErr_Occurred()) {
1186 /* The conversion failed. */
1187 }
1188
Tim Petersbdee63f2001-09-02 03:40:59 +00001189- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001190 compile but will not participate in GC. To upgrade an extension
1191 module:
1192
1193 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001194
Neil Schemenauer4042c692001-08-30 15:38:01 +00001195 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1196 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001197
Neil Schemenauer4042c692001-08-30 15:38:01 +00001198 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1199 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001200
Neil Schemenauer4042c692001-08-30 15:38:01 +00001201 - remove PyGC_HEAD_SIZE from object size calculations
1202
1203 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1204
Tim Petersbdee63f2001-09-02 03:40:59 +00001205- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001206 These can be used safely to construct string objects from a
1207 sprintf-style format string (similar to the format string supported
1208 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001209
Tim Petersedc99312001-08-22 21:36:50 +00001210New platforms
1211
Tim Petersb7da0902001-09-02 23:01:43 +00001212- Stephen Hansen contributed patches sufficient to get a clean compile
1213 under Borland C (Windows), but he reports problems running it and ran
1214 out of time to complete the port. Volunteers? Expect a MemoryError
1215 when importing the types module; this is probably shallow, and
1216 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001217
Tim Petersedc99312001-08-22 21:36:50 +00001218Tests
1219
1220Windows
1221
Tim Peters6e13a562001-09-06 00:32:15 +00001222- Large file support is now enabled on Win32 platforms as well as on
1223 Win64. This means that, for example, you can use f.tell() and f.seek()
1224 to manipulate files larger than 2 gigabytes (provided you have enough
1225 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001226 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1227 filesize limit, and large file support makes no difference there.
1228 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1229 NTFS has no practical limit on file size, and files of any size can be
1230 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001231
Tim Petersbdee63f2001-09-02 03:40:59 +00001232- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001233 points to command.com (patch from Brian Quinlan).
1234
Tim Petersedc99312001-08-22 21:36:50 +00001235
Tim Peters20f51a72001-07-21 02:31:40 +00001236What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001237Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001238===========================
1239
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001240Build
1241
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001242- Tim Peters developed a brand new Windows installer using Wise 8.1,
1243 generously donated to us by Wise Solutions.
1244
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001245- configure supports a new option --enable-unicode, with the values
1246 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1247 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001248
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001249- A new configure option --enable-framework builds a Mac OS X framework,
1250 which "make frameworkinstall" will install. This provides a starting
1251 point for more mac-like functionality, join pythonmac-sig@python.org
1252 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001253
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001254- The NeXT platform is no longer supported.
1255
1256- The `new' module is now statically linked.
1257
Tim Peters0afb6092001-08-15 06:06:44 +00001258Tools
1259
1260- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001261 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001262 the module docstring for details.
1263
Tim Peters20f51a72001-07-21 02:31:40 +00001264Tests
1265
Tim Peters5e824c32001-08-12 22:25:01 +00001266- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001267 platforms, allowing to give clearer test result output. regrtest
1268 also has optional --use/-u switch to run normally disabled tests
1269 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001270
Tim Peters20f51a72001-07-21 02:31:40 +00001271- Several new tests in the standard test suite, with special thanks to
1272 Nick Mathewson.
1273
1274Core
1275
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001276- The floor division operator // has been added as outlined in PEP
1277 238. The / operator still provides classic division (and will until
1278 Python 3.0) unless "from __future__ import division" is included, in
1279 which case the / operator will provide true division. The operator
1280 module provides truediv() and floordiv() functions. Augmented
1281 assignment variants are included, as are the equivalent overloadable
1282 methods and C API methods. See the PEP for a full discussion:
1283 <http://python.sf.net/peps/pep-0238.html>
1284
Tim Peters6cd6a822001-08-17 22:11:27 +00001285- Future statements are now effective in simulated interactive shells
1286 (like IDLE). This should "just work" by magic, but read Michael
1287 Hudson's "Future statements in simulated shells" PEP 264 for full
1288 details: <http://python.sf.net/peps/pep-0264.html>.
1289
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001290- The type/class unification (PEP 252-253) was integrated into the
1291 trunk and is not so tentative any more (the exact specification of
1292 some features is still tentative). A lot of work has done on fixing
1293 bugs and adding robustness and features (performance still has to
1294 come a long way).
1295
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001296- Warnings about a mismatch in the Python API during extension import
1297 now use the Python warning framework (which makes it possible to
1298 write filters for these warnings).
1299
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001300- A function's __dict__ (aka func_dict) will now always be a
1301 dictionary. It used to be possible to delete it or set it to None,
1302 but now both actions raise TypeErrors. It is still legal to set it
1303 to a dictionary object. Getting func.__dict__ before any attributes
1304 have been assigned now returns an empty dictionary instead of None.
1305
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001306- A new command line option, -E, was added which disables the use of
1307 all environment variables, or at least those that are specifically
1308 significant to Python. Usually those have a name starting with
1309 "PYTHON". This was used to fix a problem where the tests fail if
1310 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1311 older distribution.
1312
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001313Library
1314
Tim Peters5e824c32001-08-12 22:25:01 +00001315- New class Differ and new functions ndiff() and restore() in difflib.py.
1316 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001317 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001318
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001319- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1320 value using the minimal quoting required for the value; more
1321 reliable than using xml.sax.saxutils.escape() for attribute values.
1322
1323- Readline completion support for cmd.Cmd was added.
1324
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001325- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1326
1327- Added function threading.BoundedSemaphore()
1328
1329- Added Ka-Ping Yee's cgitb.py module.
1330
1331- The `new' module now exposes the CO_xxx flags.
1332
Martin v. Löwis560da622001-11-24 09:24:51 +00001333- The gc module offers the get_referents function.
1334
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001335New platforms
1336
1337C API
1338
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001339- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1340 which provide a cross-platform implementations for the
1341 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1342 the standard sprintf() and vsprintf() C lib APIs, these versions
1343 apply bounds checking on the used buffer which enhances protection
1344 against buffer overruns.
1345
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001346- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001347 and extensions using different Unicode widths is rendered next to
1348 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001349 will result in an ImportError. Unicode extensions writers must make
1350 sure to check the Unicode width compatibility in their extensions by
1351 using at least one of the mangled Unicode APIs in the extension.
1352
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001353- Two new flags METH_NOARGS and METH_O are available in method definition
1354 tables to simplify implementation of methods with no arguments and a
1355 single untyped argument. Calling such methods is more efficient than
1356 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1357 deprecated.
1358
Tim Petersc1731372001-08-04 08:12:36 +00001359Windows
1360
1361- "import module" now compiles module.pyw if it exists and nothing else
1362 relevant is found.
1363
Tim Peters20f51a72001-07-21 02:31:40 +00001364
Guido van Rossum55a78992001-07-17 17:22:32 +00001365What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001366Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001367===========================
1368
1369Core
Tim Petersa814db52001-05-14 07:05:58 +00001370
Tim Peters6d6c1a32001-08-02 04:15:00 +00001371- TENTATIVELY, a large amount of code implementing much of what's
1372 described in PEP 252 (Making Types Look More Like Classes) and PEP
1373 253 (Subtyping Built-in Types) was added. This will be released
1374 with Python 2.2a1. Documentation will be provided separately
1375 through http://www.python.org/2.2/. The purpose of releasing this
1376 with Python 2.2a1 is to test backwards compatibility. It is
1377 possible, though not likely, that a decision is made not to release
1378 this code as part of 2.2 final, if any serious backwards
1379 incompapatibilities are found during alpha testing that cannot be
1380 repaired.
1381
Guido van Rossum55a78992001-07-17 17:22:32 +00001382- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001383 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001384 more 'yield' statements. See PEP 255. Since this adds a new
1385 keyword to the language, this feature must be enabled by including a
1386 future statement: "from __future__ import generators" (see PEP 236).
1387 Generators will become a standard feature in a future release
1388 (probably 2.3). Without this future statement, 'yield' remains an
1389 ordinary identifier, but a warning is issued each time it is used.
1390 (These warnings currently don't conform to the warnings framework of
1391 PEP 230; we intend to fix this in 2.2a2.)
1392
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001393- The UTF-16 codec was modified to be more RFC compliant. It will now
1394 only remove BOM characters at the start of the string and then
1395 only if running in native mode (UTF-16-LE and -BE won't remove a
1396 leading BMO character).
1397
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001398- Strings now have a new method .decode() to complement the already
1399 existing .encode() method. These two methods provide direct access
1400 to the corresponding decoders and encoders of the registered codecs.
1401
1402 To enhance the usability of the .encode() method, the special
1403 casing of Unicode object return values was dropped (Unicode objects
1404 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001405
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001406 Both methods will now return whatever the codec in charge of the
1407 requested encoding returns as object, e.g. Unicode codecs will
1408 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1409 will return u"äöü"). This enables codec writer to create codecs
1410 for various simple to use conversions.
1411
1412 New codecs were added to demonstrate these new features (the .encode()
1413 and .decode() columns indicate the type of the returned objects):
1414
1415 Name | .encode() | .decode() | Description
1416 ----------------------------------------------------------------------
1417 uu | string | string | UU codec (e.g. for email)
1418 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001419 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001420 zlib | string | string | zlib compression
1421 hex | string | string | 2-byte hex codec
1422 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1423
Mark Hammond2a0af792001-05-14 03:09:36 +00001424- Some operating systems now support the concept of a default Unicode
1425 encoding for file system operations. Notably, Windows supports 'mbcs'
1426 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001427 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001428 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001429
1430 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001431 functions that return filenames (such as os.listdir()) to return Python
1432 string objects pre-encoded using the default file system encoding for
1433 the platform. As this encoding is likely to be different from Python's
1434 default encoding, converting this name to a Unicode object before passing
1435 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001436 would attempt to use its default encoding (generally ASCII) rather than
1437 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001438
Tim Petersa814db52001-05-14 07:05:58 +00001439 In general, this change simply removes surprises when working with
1440 Unicode and the file system, making these operations work as you expect,
1441 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001442 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001443
Tim Peters61dff2b2001-05-08 15:43:37 +00001444- Float (and complex) literals in source code were evaluated to full
1445 precision only when running from a .py file; the same code loaded from a
1446 .pyc (or .pyo) file could suffer numeric differences starting at about the
1447 12th significant decimal digit. For example, on a machine with IEEE-754
1448 floating arithmetic,
1449
1450 x = 9007199254740992.0
1451 print long(x)
1452
1453 printed 9007199254740992 if run directly from .py, but 9007199254740000
1454 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1455 str(float) instead of repr(float) when building code objects. marshal
1456 now uses repr(float) instead, which should reproduce floats to full
1457 machine precision (assuming the platform C float<->string I/O conversion
1458 functions are of good quality).
1459
1460 This may cause floating-point results to change in some cases, and
1461 usually for the better, but may also cause numerically unstable
1462 algorithms to break.
1463
Tim Peters2f228e72001-05-13 00:19:31 +00001464- The implementation of dicts suffers fewer collisions, which has speed
1465 benefits. However, the order in which dict entries appear in dict.keys(),
1466 dict.values() and dict.items() may differ from previous releases for a
1467 given dict. Nothing is defined about this order, so no program should
1468 rely on it. Nevertheless, it's easy to write test cases that rely on the
1469 order by accident, typically because of printing the str() or repr() of a
1470 dict to an "expected results" file. See Lib/test/test_support.py's new
1471 sortdict(dict) function for a simple way to display a dict in sorted
1472 order.
1473
Tim Peters7a3bfc32001-06-12 01:22:22 +00001474- Many other small changes to dicts were made, resulting in faster
1475 operation along the most common code paths.
1476
Guido van Rossum10315822001-05-01 20:54:30 +00001477- Dictionary objects now support the "in" operator: "x in dict" means
1478 the same as dict.has_key(x).
1479
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001480- The update() method of dictionaries now accepts generic mapping
1481 objects. Specifically the argument object must support the .keys()
1482 and __getitem__() methods. This allows you to say, for example,
1483 {}.update(UserDict())
1484
Guido van Rossum10315822001-05-01 20:54:30 +00001485- Iterators were added; this is a generalized way of providing values
1486 to a for loop. See PEP 234. There's a new built-in function iter()
1487 to return an iterator. There's a new protocol to get the next value
1488 from an iterator using the next() method (in Python) or the
1489 tp_iternext slot (in C). There's a new protocol to get iterators
1490 using the __iter__() method (in Python) or the tp_iter slot (in C).
1491 Iterating (i.e. a for loop) over a dictionary generates its keys.
1492 Iterating over a file generates its lines.
1493
Tim Petersf553f892001-05-01 20:45:31 +00001494- The following functions were generalized to work nicely with iterator
1495 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001496 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001497 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1498 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001499 join() method of strings
1500 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001501 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1502 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001503 right-hand side of assignment statements with multiple targets, such as
1504 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001505
Tim Petersd85e1022001-05-11 21:51:48 +00001506- Accessing module attributes is significantly faster (for example,
1507 random.random or os.path or yourPythonModule.yourAttribute).
1508
Tim Peterse63415e2001-05-08 04:38:29 +00001509- Comparing dictionary objects via == and != is faster, and now works even
1510 if the keys and values don't support comparisons other than ==.
1511
Tim Peters95bf9392001-05-10 08:32:44 +00001512- Comparing dictionaries in ways other than == and != is slower: there were
1513 insecurities in the dict comparison implementation that could cause Python
1514 to crash if the element comparison routines for the dict keys and/or
1515 values mutated the dicts. Making the code bulletproof slowed it down.
1516
Tim Peterseb28ef22001-06-02 05:27:19 +00001517- Collisions in dicts are resolved via a new approach, which can help
1518 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001519 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001520 faster now. Thanks to Christian Tismer for pointing out the cause and
1521 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001522
Tim Peters52e155e2001-06-16 05:42:57 +00001523- repr() is much faster for large containers (dict, list, tuple).
1524
1525
Tim Petersa814db52001-05-14 07:05:58 +00001526Library
1527
Fred Drake960fdf92001-07-20 18:38:26 +00001528- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1529 were added to the string module. These a locale-indenpendent
1530 constants, unlike letters, lowercase, and uppercase. These are now
1531 use in appropriate locations in the standard library.
1532
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001533- The flags used in dlopen calls can now be configured using
1534 sys.setdlopenflags and queried using sys.getdlopenflags.
1535
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001536- Fredrik Lundh's xmlrpclib is now a standard library module. This
1537 provides full client-side XML-RPC support. In addition,
1538 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1539 one asyncore-based). Thanks to Eric Raymond for the documentation.
1540
Guido van Rossum643d3912001-07-05 14:46:25 +00001541- The xrange() object is simplified: it no longer supports slicing,
1542 repetition, comparisons, efficient 'in' checking, the tolist()
1543 method, or the start, stop and step attributes. See PEP 260.
1544
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001545- A new function fnmatch.filter to filter lists of file names was added.
1546
Barry Warsawffd674d2001-05-22 16:00:10 +00001547- calendar.py uses month and day names based on the current locale.
1548
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001549- strop is now *really* obsolete (this was announced before with 1.6),
1550 and issues DeprecationWarning when used (except for the four items
1551 that are still imported into string.py).
1552
Tim Petersa814db52001-05-14 07:05:58 +00001553- Cookie.py now sorts key+value pairs by key in output strings.
1554
1555- pprint.isrecursive(object) didn't correctly identify recursive objects.
1556 Now it does.
1557
Tim Peters95b3f782001-05-14 18:39:41 +00001558- pprint functions now much faster for large containers (tuple, list, dict).
1559
Tim Peters7b9542a2001-06-10 23:40:19 +00001560- New 'q' and 'Q' format codes in the struct module, corresponding to C
1561 types "long long" and "unsigned long long" (on Windows, __int64). In
1562 native mode, these can be used only when the platform C compiler supports
1563 these types (when HAVE_LONG_LONG is #define'd by the Python config
1564 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001565 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1566 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001567
Guido van Rossum83213cc2001-06-12 16:48:52 +00001568- The site module installs a new built-in function 'help' that invokes
1569 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1570 it displays a message reminding the user to use 'help()' or
1571 'help(object)'.
1572
Tim Petersa814db52001-05-14 07:05:58 +00001573Tests
1574
1575- New test_mutants.py runs dict comparisons where the key and value
1576 comparison operators mutute the dicts randomly during comparison. This
1577 rapidly causes Python to crash under earlier releases (not for the faint
1578 of heart: it can also cause Win9x to freeze or reboot!).
1579
1580- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001581 pprint.isreadable() return sensible results. Also verifies that simple
1582 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001583
Tim Peters4324aa32001-05-28 22:30:08 +00001584C API
1585
1586- Removed the unused last_is_sticky argument from the internal
1587 _PyTuple_Resize(). If this affects you, you were cheating.
1588
1589
Guido van Rossum55a78992001-07-17 17:22:32 +00001590======================================================================
1591
1592
Guido van Rossumffe13be2001-04-16 18:46:45 +00001593What's New in Python 2.1 (final)?
1594=================================
1595
1596We only changed a few things since the last release candidate, all in
1597Python library code:
1598
1599- A bug in the locale module was fixed that affected locales which
1600 define no grouping for numeric formatting.
1601
1602- A few bugs in the weakref module's implementations of weak
1603 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1604 and the test suite was updated to check for these bugs.
1605
1606- An old bug in the os.path.walk() function (introduced in Python
1607 2.0!) was fixed: a non-existent file would cause an exception
1608 instead of being ignored.
1609
1610- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1611 PyChecker.
1612
1613
Guido van Rossum5b08f132001-04-16 02:05:23 +00001614What's New in Python 2.1c2?
1615===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001616
Guido van Rossum5b08f132001-04-16 02:05:23 +00001617A flurry of small changes, and one showstopper fixed in the nick of
1618time made it necessary to release another release candidate. The list
1619here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001620
Guido van Rossum5b08f132001-04-16 02:05:23 +00001621Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001622
Guido van Rossum5b08f132001-04-16 02:05:23 +00001623- Tim discovered a nasty bug in the dictionary code, caused by
1624 PyDict_Next() calling dict_resize(), and the GC code's use of
1625 PyDict_Next() violating an assumption in dict_items(). This was
1626 fixed with considerable amounts of band-aid, but the net effect is a
1627 saner and more robust implementation.
1628
1629- Made a bunch of symbols static that were accidentally global.
1630
1631Build and Ports
1632
1633- The setup.py script didn't check for a new enough version of zlib
1634 (1.1.3 is needed). Now it does.
1635
1636- Changed "make clean" target to also remove shared libraries.
1637
1638- Added a more general warning about the SGI Irix optimizer to README.
1639
1640Library
1641
1642- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1643 omitted the slash between host and file.html.
1644
1645- The mailbox module's _Mailbox class contained a completely broken
1646 and undocumented seek() method. Ripped it out.
1647
1648- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1649 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1650
1651- Fixed a few last-minute bugs in unittest.
1652
1653Extensions
1654
1655- Reverted the patch to the OpenSSL code in socketmodule.c to support
1656 RAND_status() and the EGD, and the subsequent patch that tried to
1657 fix it for pre-0.9.5 versions; the problem with the patch is that on
1658 some systems it issues a warning whenever socket is imported, and
1659 that's unacceptable.
1660
1661Tests
1662
1663- Fixed the pickle tests to work with "import test.test_pickle".
1664
1665- Tweaked test_locale.py to actually run the test Windows.
1666
1667- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1668 not "wb" (which is not a valid mode at all).
1669
1670- Fix pstats browser crashes. Import readline if it exists to make
1671 the user interface nicer.
1672
1673- Add "import thread" to the top of test modules that import the
1674 threading module (test_asynchat and test_threadedtempfile). This
1675 prevents test failures caused by a broken threading module resulting
1676 from a previously caught failed import.
1677
1678- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1679 needed on some platforms (e.g. Solaris 8) when the tests are run
1680 twice in succession.
1681
1682- Skip rather than fail test_sunaudiodev if no audio device is found.
1683
1684
1685What's New in Python 2.1c1?
1686===========================
1687
1688This list was significantly updated when 2.1c2 was released; the 2.1c1
1689release didn't mention most changes that were actually part of 2.1c1:
1690
1691Legal
1692
1693- Copyright was assigned to the Python Software Foundation (PSF) and a
1694 PSF license (very similar to the CNRI license) was added.
1695
1696- The CNRI copyright notice was updated to include 2001.
1697
1698Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001699
Guido van Rossumc9932722001-04-12 02:31:27 +00001700- After a public outcry, assignment to __debug__ is no longer illegal;
1701 instead, a warning is issued. It will become illegal in 2.2.
1702
Guido van Rossum5b08f132001-04-16 02:05:23 +00001703- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1704 "%#x" now always prepends "0x", even if the value is zero.
1705
1706- Fixed some nits in the bytecode compiler.
1707
1708- Fixed core dumps when calling certain kinds of non-functions.
1709
1710- Fixed various core dumps caused by reference count bugs.
1711
1712Build and Ports
1713
1714- Use INSTALL_SCRIPT to install script files.
1715
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001716- New port: SCO Unixware 7, by Billy G. Allie.
1717
Guido van Rossum5b08f132001-04-16 02:05:23 +00001718- Updated RISCOS port.
1719
1720- Updated BeOS port and notes.
1721
1722- Various other porting problems resolved.
1723
1724Library
1725
1726- The TERMIOS and SOCKET modules are now truly obsolete and
1727 unnecessary. Their symbols are incorporated in the termios and
1728 socket modules.
1729
1730- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1731 better tests for pickling.
1732
1733- threading: make Condition.wait() robust against KeyboardInterrupt.
1734
1735- zipfile: add support to zipfile to support opening an archive
1736 represented by an open file rather than a file name. Fix bug where
1737 the archive was not properly closed. Fixed a bug in this bugfix
1738 where flush() was called for a read-only file.
1739
1740- imputil: added an uninstall() method to the ImportManager.
1741
1742- Canvas: fixed bugs in lower() and tkraise() methods.
1743
1744- SocketServer: API change (added overridable close_request() method)
1745 so that the TCP server can explicitly close the request.
1746
1747- pstats: Eric Raymond added a simple interactive statistics browser,
1748 invoked when the module is run as a script.
1749
1750- locale: fixed a problem in format().
1751
1752- webbrowser: made it work when the BROWSER environment variable has a
1753 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1754 KDE 2. Fixed some other nits.
1755
1756- unittest: changes to allow using a different exception than
1757 AssertionError, and added a few more function aliases. Some other
1758 small changes.
1759
1760- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1761
1762- asynchat: fixed a critical bug in asynchat that slipped through the
1763 2.1b2 release. Fixed another rare bug.
1764
1765- Fix some unqualified except: clauses (always a bad code example).
1766
1767XML
1768
1769- pyexpat: new API get_version_string().
1770
1771- Fixed some minidom bugs.
1772
1773Extensions
1774
1775- Fixed a core dump in _weakref. Removed the weakref.mapping()
1776 function (it adds nothing to the API).
1777
1778- Rationalized the use of header files in the readline module, to make
1779 it compile (albeit with some warnings) with the very recent readline
1780 4.2, without breaking for earlier versions.
1781
1782- Hopefully fixed a buffering problem in linuxaudiodev.
1783
1784- Attempted a fix to make the OpenSSL support in the socket module
1785 work again with pre-0.9.5 versions of OpenSSL.
1786
1787Tests
1788
1789- Added a test case for asynchat and asyncore.
1790
1791- Removed coupling between tests where one test failing could break
1792 another.
1793
1794Tools
1795
1796- Ping added an interactive help browser to pydoc, fixed some nits
1797 in the rest of the pydoc code, and added some features to his
1798 inspect module.
1799
1800- An updated python-mode.el version 4.1 which integrates Ken
1801 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1802 much nicer in XEmacs and Emacs. When stepping through your program
1803 with pdb, in either the shell window or the *Python* window, the
1804 source file and line will be tracked by an arrow. Very cool!
1805
1806- IDLE: syntax warnings in interactive mode are changed into errors.
1807
1808- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001809 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001810
1811- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001812
Barry Warsaw11e89c72001-04-11 20:37:57 +00001813
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001814What's New in Python 2.1 beta 2?
1815================================
1816
Guido van Rossum053ae352001-03-22 14:17:21 +00001817(Unlisted are many fixed bugs, more documentation, etc.)
1818
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001819Core language, builtins, and interpreter
1820
Guido van Rossum053ae352001-03-22 14:17:21 +00001821- The nested scopes work (enabled by "from __future__ import
1822 nested_scopes") is completed; in particular, the future now extends
1823 into code executed through exec, eval() and execfile(), and into the
1824 interactive interpreter.
1825
1826- When calling a base class method (e.g. BaseClass.__init__(self)),
1827 this is now allowed even if self is not strictly spoken a class
1828 instance (e.g. when using metaclasses or the Don Beaudry hook).
1829
1830- Slice objects are now comparable but not hashable; this prevents
1831 dict[:] from being accepted but meaningless.
1832
1833- Complex division is now calculated using less braindead algorithms.
1834 This doesn't change semantics except it's more likely to give useful
1835 results in extreme cases. Complex repr() now uses full precision
1836 like float repr().
1837
1838- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1839
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001840- It is illegal to assign to the name __debug__, which is set when the
1841 interpreter starts. It is effectively a compile-time constant.
1842
1843- A warning will be issued if a global statement for a variable
1844 follows a use or assignment of that variable.
1845
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001846Standard library
1847
Guido van Rossum053ae352001-03-22 14:17:21 +00001848- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1849 inspired by JUnit), is now part of the standard library. You now
1850 have a choice of two testing frameworks: unittest requires you to
1851 write testcases as separate code, doctest gathers them from
1852 docstrings. Both approaches have their advantages and
1853 disadvantages.
1854
1855- A new module Tix was added, which wraps the Tix extension library
1856 for Tk. With that module, it is not necessary to statically link
1857 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1858 require" command. See Demo/tix/.
1859
1860- tzparse.py is now obsolete.
1861
1862- In gzip.py, the seek() and tell() methods are removed -- they were
1863 non-functional anyway, and it's better if callers can test for their
1864 existence with hasattr().
1865
1866Python/C API
1867
1868- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1869 that's already in the dictionary during a PyDict_Next() iteration.
1870 This used to fail occasionally when a dictionary resize operation
1871 could be triggered that would rehash all the keys. All other
1872 modifications to the dictionary are still off-limits during a
1873 PyDict_Next() iteration!
1874
1875- New extended APIs related to passing compiler variables around.
1876
1877- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1878 implement isinstance() and issubclass().
1879
1880- Py_BuildValue() now has a "D" conversion to create a Python complex
1881 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001882
Fred Drake4e262a92001-03-22 18:26:47 +00001883- Extensions types which support weak references must now set the
1884 field allocated for the weak reference machinery to NULL themselves;
1885 this is done to avoid the cost of checking each object for having a
1886 weakly referencable type in PyObject_INIT(), since most types are
1887 not weakly referencable.
1888
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001889- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1890 free variables and cell variables to and from the frame's f_locals.
1891
1892- Variants of several functions defined in pythonrun.h have been added
1893 to support the nested_scopes future statement. The variants all end
1894 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1895 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1896 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001897 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001898
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001899Distutils
1900
1901- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1902 into the release tree.
1903
Tim Peters0e57abf2001-05-02 07:39:38 +00001904- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001905 (an uninstaller, more customization of the installer's display)
1906
1907- from Jack Jansen: added Mac-specific code to generate a dialog for
1908 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001909 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001910 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001911
1912- added 'platforms' and 'keywords' to the set of metadata that can be
1913 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001914
1915- applied patches from Jason Tishler to make the compiler class work with
1916 Cygwin.
1917
1918
Tim Peters2fe289a2001-03-01 22:19:38 +00001919What's New in Python 2.1 beta 1?
1920================================
Tim Petersd66595f2001-02-04 03:09:53 +00001921
1922Core language, builtins, and interpreter
1923
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001924- Following an outcry from the community about the amount of code
1925 broken by the nested scopes feature introduced in 2.1a2, we decided
1926 to make this feature optional, and to wait until Python 2.2 (or at
1927 least 6 months) to make it standard. The option can be enabled on a
1928 per-module basis by adding "from __future__ import nested_scopes" at
1929 the beginning of a module (before any other statements, but after
1930 comments and an optional docstring). See PEP 236 (Back to the
1931 __future__) for a description of the __future__ statement. PEP 227
1932 (Statically Nested Scopes) has been updated to reflect this change,
1933 and to clarify the semantics in a number of endcases.
1934
1935- The nested scopes code, when enabled, has been hardened, and most
1936 bugs and memory leaks in it have been fixed.
1937
1938- Compile-time warnings are now generated for a number of conditions
1939 that will break or change in meaning when nested scopes are enabled:
1940
1941 - Using "from...import *" or "exec" without in-clause in a function
1942 scope that also defines a lambda or nested function with one or
1943 more free (non-local) variables. The presence of the import* or
1944 bare exec makes it impossible for the compiler to determine the
1945 exact set of local variables in the outer scope, which makes it
1946 impossible to determine the bindings for free variables in the
1947 inner scope. To avoid the warning about import *, change it into
1948 an import of explicitly name object, or move the import* statement
1949 to the global scope; to avoid the warning about bare exec, use
1950 exec...in... (a good idea anyway -- there's a possibility that
1951 bare exec will be deprecated in the future).
1952
1953 - Use of a global variable in a nested scope with the same name as a
1954 local variable in a surrounding scope. This will change in
1955 meaning with nested scopes: the name in the inner scope will
1956 reference the variable in the outer scope rather than the global
1957 of the same name. To avoid the warning, either rename the outer
1958 variable, or use a global statement in the inner function.
1959
Neil Schemenauera35c6882001-02-27 04:45:05 +00001960- An optional object allocator has been included. This allocator is
1961 optimized for Python objects and should be faster and use less memory
1962 than the standard system allocator. It is not enabled by default
1963 because of possible thread safety problems. The allocator is only
1964 protected by the Python interpreter lock and it is possible that some
1965 extension modules require a thread safe allocator. The object
1966 allocator can be enabled by providing the "--with-pymalloc" option to
1967 configure.
1968
Tim Petersd66595f2001-02-04 03:09:53 +00001969Standard library
1970
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001971- pyexpat now detects the expat version if expat.h defines it. A
1972 number of additional handlers are provided, which are only available
1973 since expat 1.95. In addition, the methods SetParamEntityParsing and
1974 GetInputContext of Parser objects are available with 1.95.x
1975 only. Parser objects now provide the ordered_attributes and
1976 specified_attributes attributes. A new module expat.model was added,
1977 which offers a number of additional constants if 1.95.x is used.
1978
1979- xml.dom offers the new functions registerDOMImplementation and
1980 getDOMImplementation.
1981
1982- xml.dom.minidom offers a toprettyxml method. A number of DOM
1983 conformance issues have been resolved. In particular, Element now
1984 has an hasAttributes method, and the handling of namespaces was
1985 improved.
1986
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001987- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1988 getting information about live Python code, and pydoc.py, a module
1989 for interactively converting docstrings to HTML or text.
1990 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001991 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001992 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1993 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001994
Tim Peters1eff7962001-03-01 02:31:33 +00001995- New library module difflib.py, primarily packaging the SequenceMatcher
1996 class at the heart of the popular ndiff.py file-comparison tool.
1997
1998- doctest.py (a framework for verifying Python code examples in docstrings)
1999 is now part of the std library.
2000
Tim Petersd66595f2001-02-04 03:09:53 +00002001Windows changes
2002
Guido van Rossume3955a82001-03-02 14:05:59 +00002003- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2004 small GUI that lets you browse the module docstrings using your
2005 default web browser.
2006
Tim Peters1eff7962001-03-01 02:31:33 +00002007- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2008 Platforms) is implemented. See
2009
2010 http://python.sourceforge.net/peps/pep-0235.html
2011
2012 for full details, especially the "Current Lower-Left Semantics" section.
2013 The new Windows import rules are simpler than before:
2014
2015 A. If the PYTHONCASEOK environment variable exists, same as
2016 before: silently accept the first case-insensitive match of any
2017 kind; raise ImportError if none found.
2018
2019 B. Else search sys.path for the first case-sensitive match; raise
2020 ImportError if none found.
2021
2022 The same rules have been implented on other platforms with case-
2023 insensitive but case-preserving filesystems too (including Cygwin, and
2024 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002025
Tim Peters25a9ce32001-02-19 07:06:36 +00002026- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2027 what it's supposed to do (and does do under NT and 2000) via direct
2028 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002029 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002030 all Win9x systems before.
2031
Tim Peters1eff7962001-03-01 02:31:33 +00002032- Build: Subproject _test (effectively) renamed to _testcapi.
2033
Tim Peters2fe289a2001-03-01 22:19:38 +00002034New platforms
2035
2036- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2037 Thanks to Steven Majewski!
2038
2039- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2040 Tishler!
2041
Guido van Rossum9089b272001-03-02 06:49:50 +00002042- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2043 Schwertberger! See RISCOS/README for more information -- it seems
2044 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002045 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002046
Tim Peters25a9ce32001-02-19 07:06:36 +00002047
Tim Petersd7b5e882001-01-25 03:36:26 +00002048What's New in Python 2.1 alpha 2?
2049=================================
Tim Peters40ead762001-01-27 05:35:26 +00002050
Tim Petersd7b5e882001-01-25 03:36:26 +00002051Core language, builtins, and interpreter
2052
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002053- Scopes nest. If a name is used in a function or class, but is not
2054 local, the definition in the nearest enclosing function scope will
2055 be used. One consequence of this change is that lambda statements
2056 could reference variables in the namespaces where the lambda is
2057 defined. In some unusual cases, this change will break code.
2058
2059 In all previous version of Python, names were resolved in exactly
2060 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002061 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002062 function A is defined within a function B, the names bound in B are
2063 not visible in A. The new rules make names bound in B visible in A,
2064 unless A contains a name binding that hides the binding in B.
2065
2066 Section 4.1 of the reference manual describes the new scoping rules
2067 in detail. The test script in Lib/test/test_scope.py demonstrates
2068 some of the effects of the change.
2069
2070 The new rules will cause existing code to break if it defines nested
2071 functions where an outer function has local variables with the same
2072 name as globals or builtins used by the inner function. Example:
2073
2074 def munge(str):
2075 def helper(x):
2076 return str(x)
2077 if type(str) != type(''):
2078 str = helper(str)
2079 return str.strip()
2080
2081 Under the old rules, the name str in helper() is bound to the
2082 builtin function str(). Under the new rules, it will be bound to
2083 the argument named str and an error will occur when helper() is
2084 called.
2085
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002086- The compiler will report a SyntaxError if "from ... import *" occurs
2087 in a function or class scope. The language reference has documented
2088 that this case is illegal, but the compiler never checked for it.
2089 The recent introduction of nested scope makes the meaning of this
2090 form of name binding ambiguous. In a future release, the compiler
2091 may allow this form when there is no possibility of ambiguity.
2092
Tim Peters40ead762001-01-27 05:35:26 +00002093- repr(string) is easier to read, now using hex escapes instead of octal,
2094 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2095
2096 >>> "\texample \r\n" + chr(0) + chr(255)
2097 '\texample \r\n\x00\xff' # in 2.1
2098 '\011example \015\012\000\377' # in 2.0
2099
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002100- Functions are now compared and hashed by identity, not by value, since
2101 the func_code attribute is writable.
2102
Fred Drakefb9d7122001-02-01 20:00:40 +00002103- Weak references (PEP 205) have been added. This involves a few
2104 changes in the core, an extension module (_weakref), and a Python
2105 module (weakref). The weakref module is the public interface. It
2106 includes support for "explicit" weak references, proxy objects, and
2107 mappings with weakly held values.
2108
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002109- A 'continue' statement can now appear in a try block within the body
2110 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002111 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002112
Tim Petersd7b5e882001-01-25 03:36:26 +00002113Standard library
2114
Barry Warsaw30dbd142001-01-31 22:14:01 +00002115- mailbox.py now has a new class, PortableUnixMailbox which is
2116 identical to UnixMailbox but uses a more portable scheme for
2117 determining From_ separators. Also, the constructors for all the
2118 classes in this module have a new optional `factory' argument, which
2119 is a callable used when new message classes must be instantiated by
2120 the next() method.
2121
Tim Petersd7b5e882001-01-25 03:36:26 +00002122- random.py is now self-contained, and offers all the functionality of
2123 the now-deprecated whrandom.py. See the docs for details. random.py
2124 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002125 and restoring the internal state of the generator; and jumpahead(n),
2126 for quickly forcing the internal state to be the same as if n calls to
2127 random() had been made. The latter is particularly useful for multi-
2128 threaded programs, creating one instance of the random.Random() class for
2129 each thread, then using .jumpahead() to force each instance to use a
2130 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002131
Tim Peters0de88fc2001-02-01 04:59:18 +00002132- random.py's seed() function is new. For bit-for-bit compatibility with
2133 prior releases, use the whseed function instead. The new seed function
2134 addresses two problems: (1) The old function couldn't produce more than
2135 about 2**24 distinct internal states; the new one about 2**45 (the best
2136 that can be done in the Wichmann-Hill generator). (2) The old function
2137 sometimes produced identical internal states when passed distinct
2138 integers, and there was no simple way to predict when that would happen;
2139 the new one guarantees to produce distinct internal states for all
2140 arguments in [0, 27814431486576L).
2141
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002142- The socket module now supports raw packets on Linux. The socket
2143 family is AF_PACKET.
2144
Tim Peters9ea17ac2001-02-02 05:57:15 +00002145- test_capi.py is a start at running tests of the Python C API. The tests
2146 are implemented by the new Modules/_testmodule.c.
2147
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002148- A new extension module, _symtable, provides provisional access to the
2149 internal symbol table used by the Python compiler. A higher-level
2150 interface will be added on top of _symtable in a future release.
2151
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002152- Removed the obsolete soundex module.
2153
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002154- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2155 the isSameNode method; NamedNodeMap the get method.
2156
2157- xml.sax.expatreader supports the lexical handler property; it
2158 generates comment, startCDATA, and endCDATA events.
2159
Tim Petersee826f82001-01-31 19:39:44 +00002160Windows changes
2161
2162- Build procedure: the zlib project is built in a different way that
2163 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002164 the zlib binary used. See PCbuild\readme.txt for details. Your old
2165 zlib-related directories can be deleted; you'll need to download fresh
2166 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002167
Tim Peters9ea17ac2001-02-02 05:57:15 +00002168- Build: New subproject _test for the benefit of test_capi.py (see above).
2169
Tim Petersb16c56f2001-02-02 21:24:51 +00002170- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2171 interface to some Python compiler internals).
2172
2173- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002174 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002175
Tim Petersa3a3a032000-11-30 05:22:44 +00002176What's New in Python 2.1 alpha 1?
2177=================================
2178
2179Core language, builtins, and interpreter
2180
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002181- There is a new Unicode companion to the PyObject_Str() API
2182 called PyObject_Unicode(). It behaves in the same way as the
2183 former, but assures that the returned value is an Unicode object
2184 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002185
Guido van Rossumf98eda02001-01-17 15:54:45 +00002186- The comparison operators support "rich comparison overloading" (PEP
2187 207). C extension types can provide a rich comparison function in
2188 the new tp_richcompare slot in the type object. The cmp() function
2189 and the C function PyObject_Compare() first try the new rich
2190 comparison operators before trying the old 3-way comparison. There
2191 is also a new C API PyObject_RichCompare() (which also falls back on
2192 the old 3-way comparison, but does not constrain the outcome of the
2193 rich comparison to a Boolean result).
2194
2195 The rich comparison function takes two objects (at least one of
2196 which is guaranteed to have the type that provided the function) and
2197 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2198 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2199 object, which may be NotImplemented (in which case the tp_compare
2200 slot function is used as a fallback, if defined).
2201
2202 Classes can overload individual comparison operators by defining one
2203 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002204 __ge__. There are no explicit "reflected argument" versions of
2205 these; instead, __lt__ and __gt__ are each other's reflection,
2206 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2207 reflection (similar at the C level). No other implications are
2208 made; in particular, Python does not assume that == is the Boolean
2209 inverse of !=, or that < is the Boolean inverse of >=. This makes
2210 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002211
2212 Classes or types that want to implement (in)equality tests but not
2213 the ordering operators (i.e. unordered types) should implement ==
2214 and !=, and raise an error for the ordering operators.
2215
Guido van Rossuma88479f2001-01-18 14:28:08 +00002216 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002217 Boolean; e.g. a matrix type might want to return a matrix of bits
2218 for A < B, giving elementwise comparisons. Such types should ensure
2219 that any interpretation of their value in a Boolean context raises
2220 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2221 at the C level) to always raise an exception.
2222
Guido van Rossuma88479f2001-01-18 14:28:08 +00002223- Complex numbers use rich comparisons to define == and != but raise
2224 an exception for <, <=, > and >=. Unfortunately, this also means
2225 that cmp() of two complex numbers raises an exception when the two
2226 numbers differ. Since it is not mathematically meaningful to compare
2227 complex numbers except for equality, I hope that this doesn't break
2228 too much code.
2229
Tim Peters3389f192001-02-18 08:48:49 +00002230- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002231 not defined by the language, other than that it's arbitrary but
2232 consistent (see the Reference Manual). An implementation detail changed
2233 in 2.1a1 such that None now compares less than any other object. Code
2234 relying on this new behavior (like code that relied on the previous
2235 behavior) does so at its own risk.
2236
Barry Warsaw573b5412001-01-15 20:43:18 +00002237- Functions and methods now support getting and setting arbitrarily
2238 named attributes (PEP 232). Functions have a new __dict__
2239 (a.k.a. func_dict) which hold the function attributes. Methods get
2240 and set attributes on their underlying im_func. It is a TypeError
2241 to set an attribute on a bound method.
2242
Guido van Rossum051e3352001-01-15 19:11:10 +00002243- The xrange() object implementation has been improved so that
2244 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2245 limitation that in this case len(xrange(sys.maxint)) can't be
2246 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2247 work fine as long as the index i doesn't actually reach 2**31.
2248 (Python uses regular ints for sequence and string indices; fixing
2249 that is much more work.)
2250
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002251- Two changes to from...import:
2252
Guido van Rossumba381232001-02-03 15:06:40 +00002253 1) "from M import X" now works even if (after loading module M)
2254 sys.modules['M'] is not a real module; it's basically a getattr()
2255 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002256
2257 2) "from M import *" now looks for M.__all__ to decide which names to
2258 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2259 filters out names starting with '_' as before. Whether or not
2260 __all__ exists, there's no restriction on the type of M.
2261
Guido van Rossumf61f1662001-01-10 20:13:55 +00002262- File objects have a new method, xreadlines(). This is the fastest
2263 way to iterate over all lines in a file:
2264
2265 for line in file.xreadlines():
2266 ...do something to line...
2267
2268 See the xreadlines module (mentioned below) for how to do this for
2269 other file-like objects.
2270
2271- Even if you don't use file.xreadlines(), you may expect a speedup on
2272 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002273 quite a bit in platform-specific ways: on systems (like Linux) that
2274 support flockfile(), getc_unlocked(), and funlockfile(), those are
2275 used by default. On systems (like Windows) without getc_unlocked(),
2276 a complicated (but still thread-safe) method using fgets() is used by
2277 default.
2278
Tim Petersd52269b2001-01-25 06:23:18 +00002279 You can force use of the fgets() method by #define'ing
2280 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002281 getc_unlocked()).
2282
Tim Petersd52269b2001-01-25 06:23:18 +00002283 You can force fgets() not to be used by #define'ing
2284 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002285 test_bufio.py fails -- and let us know if it does!).
2286
2287- In addition, the fileinput module, while still slower than the other
2288 methods on most platforms, has been sped up too, by using
2289 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002290
2291- Support for run-time warnings has been added, including a new
2292 command line option (-W) to specify the disposition of warnings.
2293 See the description of the warnings module below.
2294
2295- Extensive changes have been made to the coercion code. This mostly
2296 affects extension modules (which can now implement mixed-type
2297 numerical operators without having to use coercion), but
2298 occasionally, in boundary cases the coercion semantics have changed
2299 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002300 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002301 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002302 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002303
Guido van Rossumf98eda02001-01-17 15:54:45 +00002304- In connection with the coercion changes, a new built-in singleton
2305 object, NotImplemented is defined. This can be returned for
2306 operations that wish to indicate they are not implemented for a
2307 particular combination of arguments. From C, this is
2308 Py_NotImplemented.
2309
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002310- The interpreter accepts now bytecode files on the command line even
2311 if they do not have a .pyc or .pyo extension. On Linux, after executing
2312
Martin v. Löwise214baa2001-02-04 22:37:56 +00002313import imp,sys,string
2314magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2315reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2316open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002317
2318 any byte code file can be used as an executable (i.e. as an argument
2319 to execve(2)).
2320
Tim Peters9940b802000-12-01 07:59:35 +00002321- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002322 character. In 1.6 and earlier, they never produced a sign,
2323 and raised an error if the value of the long was too large
2324 to fit in a Python int. In 2.0, they produced a sign if and
2325 only if too large to fit in an int. This was inconsistent
2326 across platforms (because the size of an int varies across
2327 platforms), and inconsistent with hex() and oct(). Example:
2328
2329 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002330 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002331 'ffffffbe' # in 2.0 and before, on 32-bit machines
2332 >>> hex(-0x42L)
2333 '-0x42L' # in all versions of Python
2334
Tim Peters9940b802000-12-01 07:59:35 +00002335 The behavior of %d formats for negative Python longs remains
2336 the same as in 2.0 (although in 1.6 and before, they raised
2337 an error if the long didn't fit in a Python int).
2338
2339 %u formats don't make sense for Python longs, but are allowed
2340 and treated the same as %d in 2.1. In 2.0, a negative long
2341 formatted via %u produced a sign if and only if too large to
2342 fit in an int. In 1.6 and earlier, a negative long formatted
2343 via %u raised an error if it was too big to fit in an int.
2344
Guido van Rossum3661d392000-12-12 22:10:31 +00002345- Dictionary objects have an odd new method, popitem(). This removes
2346 an arbitrary item from the dictionary and returns it (in the form of
2347 a (key, value) pair). This can be useful for algorithms that use a
2348 dictionary as a bag of "to do" items and repeatedly need to pick one
2349 item. Such algorithms normally end up running in quadratic time;
2350 using popitem() they can usually be made to run in linear time.
2351
Tim Peters36cdad12000-12-29 02:06:45 +00002352Standard library
2353
Thomas Woutersfe385252001-01-19 23:16:56 +00002354- In the time module, the time argument to the functions strftime,
2355 localtime, gmtime, asctime and ctime is now optional, defaulting to
2356 the current time (in the local timezone).
2357
Guido van Rossumda91f222001-01-15 16:36:08 +00002358- The ftplib module now defaults to passive mode, which is deemed a
2359 more useful default given that clients are often inside firewalls
2360 these days. Note that this could break if ftplib is used to connect
2361 to a *server* that is inside a firewall, from outside; this is
2362 expected to be a very rare situation. To fix that, you can call
2363 ftp.set_pasv(0).
2364
Martin v. Löwis10a27872001-01-13 09:54:41 +00002365- The module site now treats .pth files not only for path configuration,
2366 but also supports extensions to the initialization code: Lines starting
2367 with import are executed.
2368
Guido van Rossumf61f1662001-01-10 20:13:55 +00002369- There's a new module, warnings, which implements a mechanism for
2370 issuing and filtering warnings. There are some new built-in
2371 exceptions that serve as warning categories, and a new command line
2372 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2373 turns warnings into errors). warnings.warn(message[, category])
2374 issues a warning message; this can also be called from C as
2375 PyErr_Warn(category, message).
2376
2377- A new module xreadlines was added. This exports a single factory
2378 function, xreadlines(). The intention is that this code is the
2379 absolutely fastest way to iterate over all lines in an open
2380 file(-like) object:
2381
2382 import xreadlines
2383 for line in xreadlines.xreadlines(file):
2384 ...do something to line...
2385
2386 This is equivalent to the previous the speed record holder using
2387 file.readlines(sizehint). Note that if file is a real file object
2388 (as opposed to a file-like object), this is equivalent:
2389
2390 for line in file.xreadlines():
2391 ...do something to line...
2392
Tim Peters36cdad12000-12-29 02:06:45 +00002393- The bisect module has new functions bisect_left, insort_left,
2394 bisect_right and insort_right. The old names bisect and insort
2395 are now aliases for bisect_right and insort_right. XXX_right
2396 and XXX_left methods differ in what happens when the new element
2397 compares equal to one or more elements already in the list: the
2398 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002399 right. Code that doesn't care where equal elements end up should
2400 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002401
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002402- The new curses.panel module wraps the panel library that forms part
2403 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2404
Guido van Rossumf61f1662001-01-10 20:13:55 +00002405- The SocketServer module now sets the allow_reuse_address flag by
2406 default in the TCPServer class.
2407
2408- A new function, sys._getframe(), returns the stack frame pointer of
2409 the caller. This is intended only as a building block for
2410 higher-level mechanisms such as string interpolation.
2411
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002412- The pyexpat module supports a number of new handlers, which are
2413 available only in expat 1.2. If invocation of a callback fails, it
2414 will report an additional frame in the traceback. Parser objects
2415 participate now in garbage collection. If expat reports an unknown
2416 encoding, pyexpat will try to use a Python codec; that works only
2417 for single-byte charsets. The parser type objects is exposed as
2418 XMLParserObject.
2419
2420- xml.dom now offers standard definitions for symbolic node type and
2421 exception code constants, and a hierarchy of DOM exceptions. minidom
2422 was adjusted to use them.
2423
2424- The conformance of xml.dom.minidom to the DOM specification was
2425 improved. It detects a number of additional error cases; the
2426 previous/next relationship works even when the tree is modified;
2427 Node supports the normalize() method; NamedNodeMap, DocumentType and
2428 DOMImplementation classes were added; Element supports the
2429 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2430 method.
2431
Guido van Rossumf61f1662001-01-10 20:13:55 +00002432Build issues
2433
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002434- For Unix (and Unix-compatible) builds, configuration and building of
2435 extension modules is now greatly automated. Rather than having to
2436 edit the Modules/Setup file to indicate which modules should be
2437 built and where their include files and libraries are, a
2438 distutils-based setup.py script now takes care of building most
2439 extension modules. All extension modules built this way are built
2440 as shared libraries. Only a few modules that must be linked
2441 statically are still listed in the Setup file; you won't need to
2442 edit their configuration.
2443
2444- Python should now build out of the box on Cygwin. If it doesn't,
2445 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002446
2447- Python now always uses its own (renamed) implementation of getopt()
2448 -- there's too much variation among C library getopt()
2449 implementations.
2450
2451- C++ compilers are better supported; the CXX macro is always set to a
2452 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002453
Tim Petersd92dfe02000-12-12 01:18:41 +00002454Windows changes
2455
2456- select module: By default under Windows, a select() call
2457 can specify no more than 64 sockets. Python now boosts
2458 this Microsoft default to 512. If you need even more than
2459 that, see the MS docs (you'll need to #define FD_SETSIZE
2460 and recompile Python from source).
2461
Guido van Rossumf61f1662001-01-10 20:13:55 +00002462- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2463 subdirectory is no more!
2464
Tim Petersa3a3a032000-11-30 05:22:44 +00002465
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002466What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002467=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002468
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002469Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002470changes are in the file HISTORY. If you are making the jump directly
2471from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2472HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002473
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002474Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2475the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2476http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002477
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002478--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002479
2480======================================================================
2481
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002482What's new in 2.0 (since release candidate 1)?
2483==============================================
2484
2485Standard library
2486
2487- The copy_reg module was modified to clarify its intended use: to
2488 register pickle support for extension types, not for classes.
2489 pickle() will raise a TypeError if it is passed a class.
2490
2491- Fixed a bug in gettext's "normalize and expand" code that prevented
2492 it from finding an existing .mo file.
2493
2494- Restored support for HTTP/0.9 servers in httplib.
2495
Tim Peters989b7b92000-10-16 20:24:53 +00002496- The math module was changed to stop raising OverflowError in case of
2497 underflow, and return 0 instead in underflow cases. Whether Python
2498 used to raise OverflowError in case of underflow was platform-
2499 dependent (it did when the platform math library set errno to ERANGE
2500 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002501
2502- Fixed a bug in StringIO that occurred when the file position was not
2503 at the end of the file and write() was called with enough data to
2504 extend past the end of the file.
2505
2506- Fixed a bug that caused Tkinter error messages to get lost on
2507 Windows. The bug was fixed by replacing direct use of
2508 interp->result with Tcl_GetStringResult(interp).
2509
2510- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2511 redirect response.
2512
2513- Several changes were made to distutils: Some debugging code was
2514 removed from util. Fixed the installer used when an external zip
2515 program (like WinZip) is not found; the source code for this
2516 installer is in Misc/distutils. check_lib() was modified to behave
2517 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2518 test for whether installed modules are on sys.path was changed to
2519 use both normcase() and normpath().
2520
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002521- Several minor bugs were fixed in the xml package (the minidom,
2522 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002523
2524- The regression test driver (regrtest.py) behavior when invoked with
2525 -l changed: It now reports a count of objects that are recognized as
2526 garbage but not freed by the garbage collector.
2527
Tim Peters989b7b92000-10-16 20:24:53 +00002528- The regression test for the math module was changed to test
2529 exceptional behavior when the test is run in verbose mode. Python
2530 cannot yet guarantee consistent exception behavior across platforms,
2531 so the exception part of test_math is run only in verbose mode, and
2532 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002533
2534Internals
2535
2536- PyOS_CheckStack() has been disabled on Win64, where it caused
2537 test_sre to fail.
2538
2539Build issues
2540
2541- Changed compiler flags, so that gcc is always invoked with -Wall and
2542 -Wstrict-prototypes. Users compiling Python with GCC should see
2543 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002544 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002545 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002546
Tim Petersa3a3a032000-11-30 05:22:44 +00002547- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002548
2549Tools and other miscellany
2550
2551- The compiler in Tools/compiler was updated to support the new
2552 language features introduced in 2.0: extended print statement, list
2553 comprehensions, and augmented assignments. The new compiler should
2554 also be backwards compatible with Python 1.5.2; the compiler will
2555 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002556 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002557
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002558What's new in 2.0 release candidate 1 (since beta 2)?
2559=====================================================
2560
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002561What is release candidate 1?
2562
2563We believe that release candidate 1 will fix all known bugs that we
2564intend to fix for the 2.0 final release. This release should be a bit
2565more stable than the previous betas. We would like to see even more
2566widespread testing before the final release, so we are producing this
2567release candidate. The final release will be exactly the same unless
2568any show-stopping (or brown bag) bugs are found by testers of the
2569release candidate.
2570
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002571All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002572to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002573
2574Core language, builtins, and interpreter
2575
2576- A bug that caused crashes when __coerce__ was used with augmented
2577 assignment, e.g. +=, was fixed.
2578
2579- Raise ZeroDivisionError when raising zero to a negative number,
2580 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2581 power operator and the result of math.pow(0.0, -2.0) will vary by
2582 platform. On Linux, it raises a ValueError.
2583
2584- A bug in Unicode string interpolation was fixed that occasionally
2585 caused errors with formats including "%%". For example, the
2586 following expression "%% %s" % u"abc" no longer raises a TypeError.
2587
2588- Compilation of deeply nested expressions raises MemoryError instead
2589 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2590
2591- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2592 rendering them useless. They are now written in binary mode again.
2593
2594Standard library
2595
2596- Keyword arguments are now accepted for most pattern and match object
2597 methods in SRE, the standard regular expression engine.
2598
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002599- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002600 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002601
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002602- Several bugs in the Unicode handling and error handling in _tkinter
2603 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002604
2605- Fix memory management errors in Merge() and Tkapp_Call() routines.
2606
2607- Several changes were made to cStringIO to make it compatible with
2608 the file-like object interface and with StringIO. If operations are
2609 performed on a closed object, an exception is raised. The truncate
2610 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002611 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002612
2613- There were many changes made to the linuxaudiodev module and its
2614 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002615 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002616
2617 Note that this module is named poorly, because it should work
2618 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002619 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002620
2621 The module now raises exceptions when errors occur instead of
2622 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2623 audio) and defines a getptr() method that calls the
2624 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2625
2626- The library_version attribute, introduced in an earlier beta, was
2627 removed because it can not be supported with early versions of the C
2628 readline library, which provides no way to determine the version at
2629 compile-time.
2630
2631- The binascii module is now enabled on Win64.
2632
Tim Peters46446d62000-10-09 21:19:31 +00002633- tokenize.py no longer suffers "recursion depth" errors when parsing
2634 programs with very long string literals.
2635
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002636Internals
2637
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002638- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002639 which is called when the interpreter starts up to determine where
2640 the standard library is installed. These vulnerabilities affect all
2641 previous versions of Python and can be exploited by setting very
2642 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2643 setuid Python script, although use of the wrapper in
2644 Misc/setuid-prog.c will eliminate the vulnerability.
2645
2646- Fixed garbage collection bugs in instance creation that were
2647 triggered when errors occurred during initialization. The solution,
2648 applied in cPickle and in PyInstance_New(), is to call
2649 PyObject_GC_Init() after the initialization of the object's
2650 container attributes is complete.
2651
2652- pyexpat adds definitions of PyModule_AddStringConstant and
2653 PyModule_AddObject if the Python version is less than 2.0, which
2654 provides compatibility with PyXML on Python 1.5.2.
2655
2656- If the platform has a bogus definition for LONG_BIT (the number of
2657 bits in a long), an error will be reported at compile time.
2658
2659- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2660 collection crashes and possibly other, unreported crashes.
2661
2662- Fixed a memory leak in _PyUnicode_Fini().
2663
2664Build issues
2665
2666- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002667 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002668 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002669
2670- The mmap.PAGESIZE constant is now initialized using sysconf when
2671 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2672
2673- The md5 file should now compile on all platforms.
2674
2675- The select module now compiles on platforms that do not define
2676 POLLRDNORM and related constants.
2677
2678- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002679 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002680
Jeremy Hylton10921202000-10-09 18:34:12 +00002681- BeOS: A number of changes were made to the build and installation
2682 process. ar-fake now operates on a directory of object files.
2683 dl_export.h is gone, and its macros now appear on the mwcc command
2684 line during build on PPC BeOS.
2685
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002686- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002687 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002688
2689- Cygwin: Support for shared libraries, Tkinter, and sockets.
2690
2691- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2692
2693Tools and other miscellany
2694
2695- Removed debugging prints from main used with freeze.
2696
Tim Peters46446d62000-10-09 21:19:31 +00002697- IDLE auto-indent no longer crashes when it encounters Unicode
2698 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002699
2700What's new in 2.0 beta 2 (since beta 1)?
2701========================================
2702
2703Core language, builtins, and interpreter
2704
Tim Peters482c0212000-09-26 06:33:09 +00002705- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002706 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002707
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002708- Add -h and -V command line options to print the usage message and
2709 Python version number and exit immediately.
2710
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002711- eval() and exec accept Unicode objects as code parameters.
2712
2713- getattr() and setattr() now also accept Unicode objects for the
2714 attribute name, which are converted to strings using the default
2715 encoding before lookup.
2716
2717- Multiplication on string and Unicode now does proper bounds
2718 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2719 string is too long."
2720
2721- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002722 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002723
Jeremy Hylton1b618592000-09-26 05:32:36 +00002724
2725Standard library and extensions
2726
Guido van Rossum5b08f132001-04-16 02:05:23 +00002727- socket module: the OpenSSL code now adds support for RAND_status()
2728 and EGD (Entropy Gathering Device).
2729
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002730- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002731 argument checking; it still takes no arguments.
2732
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002733- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002734
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002735- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002736
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002737- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002738
2739- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002740 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002741
2742- copy: Copy Unicode objects atomically.
2743
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002744- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002745
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002746- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002747
Fred Drake67233bc2000-09-26 16:40:27 +00002748- dbm: Add get() and setdefault() methods to dbm object. Add constant
2749 `library' to module that names the library used. Added doc strings
2750 and method names to error messages. Uses configure to determine
2751 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2752 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002753
2754- distutils: Update to version 0.9.3.
2755
2756- dl: Add several dl.RTLD_ constants.
2757
2758- fpectl: Now supported on FreeBSD.
2759
2760- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2761 found by the collector will be saved in gc.garbage. This is useful
2762 for debugging a program that creates reference cycles.
2763
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002764- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002765 of HTTP class. Do not close socket on zero-length response. Do not
2766 crash when server sends invalid content-length header.
2767
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002768- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002769
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002770- marshal: When reading a short, sign-extend on platforms where shorts
2771 are bigger than 16 bits. When reading a long, repair the unportable
2772 sign extension that was being done for 64-bit machines. (It assumed
2773 that signed right shift sign-extends.)
2774
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002775- operator: Add contains(), invert(), __invert__() as aliases for
2776 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002777
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002778- os: Add support for popen2() and popen3() on all platforms where
2779 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002780
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002781- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002782 clicking on a file in Explorer (or passing the file name to the
2783 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002784
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002785- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002786 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002787
2788- pickle: Now raises ValueError when an invalid pickle that contains
2789 a non-string repr where a string repr was expected. This behavior
2790 matches cPickle.
2791
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002794- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002795
2796- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002797 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002798 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002799
2800- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002801 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002802
2803- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002804 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002805 few cycles during startup since the first call to
2806 setdefaultencoding() will initialize the codec registry and the
2807 encodings package.
2808
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002809- socket: Support for size hint in readlines() method of object returned
2810 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002811
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002812- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002813 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002814 is followed by whitespace.
2815
Tim Petersa3a3a032000-11-30 05:22:44 +00002816- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002817
2818- struct: Check ranges for bytes and shorts.
2819
2820- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002821 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002822
2823- Tkinter: Image objects are now guaranteed to have unique ids. Set
2824 event.delta to zero if Tk version doesn't support mousewheel.
2825 Removed some debugging prints.
2826
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002827- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002828
Fred Drake67233bc2000-09-26 16:40:27 +00002829- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002830 which works around a bug in Norton AntiVirus 2000 that leads directly
2831 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002832
2833- xml: New version detection code allows PyXML to override standard
2834 XML package if PyXML version is greater than 0.6.1.
2835
Fred Drake64bb3802000-09-26 16:21:35 +00002836- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2837 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2838 tree only for nodes which are sufficiently interesting to a specific
2839 application. Does not provide the HTML-specific extensions. Still
2840 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841
Fred Drake64bb3802000-09-26 16:21:35 +00002842- xml.sax: SAX 2 support for Python, including all the handler
2843 interfaces needed to process XML 1.0 compliant XML. Some
2844 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002845
Fred Drake64bb3802000-09-26 16:21:35 +00002846- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2847 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002848
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002849
Jeremy Hylton1b618592000-09-26 05:32:36 +00002850C API
2851
2852- Add three new convenience functions for module initialization --
2853 PyModule_AddObject(), PyModule_AddIntConstant(), and
2854 PyModule_AddStringConstant().
2855
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002856- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002857 removed and add #error to Python.h if NULL isn't defined after
2858 #include of stdio.h.
2859
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002860- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002861 backwards compatibility (at the source level) with old extensions.
2862
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002863- A wrapper API was added for signal() and sigaction(). Instead of
2864 either function, always use PyOS_getsig() to get a signal handler
2865 and PyOS_setsig() to set one. A new convenience typedef
2866 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002867
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002868- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002869 internal data buffer and size of a string object -- or the default
2870 encoded version of a Unicode object.
2871
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002872- PyString_Size() and PyString_AsString() accept Unicode objects.
2873
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002874- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002875 exists). INT_MAX and LONG_MAX will always be defined, even if
2876 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002877
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002878- PyFloat_FromString takes a second argument, pend, that was
2879 effectively useless. It is now officially useless but preserved for
2880 backwards compatibility. If the pend argument is not NULL, *pend is
2881 set to NULL.
2882
2883- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2884 for the attribute name. See note on getattr() above.
2885
2886- A few bug fixes to argument processing for Unicode.
2887 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2888 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2889 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002890 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002891
2892- Py_BuildValue accepts B format (for bgen-generated code).
2893
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002894
Jeremy Hylton1b618592000-09-26 05:32:36 +00002895Internals
2896
2897- On Unix, fix code for finding Python installation directory so that
2898 it works when argv[0] is a relative path.
2899
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002900- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002901 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902 rather than by generating a copy of the object.
2903
Tim Peters482c0212000-09-26 06:33:09 +00002904- Several of the internal Unicode tables are much smaller now, and
2905 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002906
Jeremy Hylton97693b02000-09-26 17:42:51 +00002907- In the garbage collector: Fixed bug in collection of tuples. Fixed
2908 bug that caused some instances to be removed from the container set
2909 while they were still live. Fixed parsing in gc.set_debug() for
2910 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002911
2912- Fixed refcount problem in instance deallocation that only occurred
2913 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2914
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002915- On Windows, getpythonregpath is now protected against null data in
2916 registry key.
2917
2918- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002919 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002920
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002921
Jeremy Hylton1b618592000-09-26 05:32:36 +00002922Build and platform-specific issues
2923
2924- Better support of GNU Pth via --with-pth configure option.
2925
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002926- Python/C API now properly exposed to dynamically-loaded extension
2927 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002928
2929- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2930 Don't define MS_SYNC to be zero when it is undefined. Added missing
2931 prototypes in posixmodule.c.
2932
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002933- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002934 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002935
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002936- Fix largefile support on older NetBSD systems and OpenBSD by adding
2937 define for TELL64.
2938
2939
2940Tools and other miscellany
2941
2942- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2943
2944- freeze: The modulefinder now works with 2.0 opcodes.
2945
Tim Petersa3a3a032000-11-30 05:22:44 +00002946- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002947 Move hackery of sys.argv until after the Tk instance has been
2948 created, which allows the application-specific Tkinter
2949 initialization to be executed if present; also pass an explicit
2950 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002951
Jeremy Hylton1b618592000-09-26 05:32:36 +00002952
2953What's new in 2.0 beta 1?
2954=========================
2955
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002956Source Incompatibilities
2957------------------------
2958
2959None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2960such as single-argument append(), connect() and bind(), and changes to
2961str(long) and repr(float).
2962
2963
2964Binary Incompatibilities
2965------------------------
2966
2967- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2968with Python 2.0; these extensions will have to be rebuilt for Python
29692.0.
2970
2971- On Windows, attempting to import a third party extension built for
2972Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2973can do about this. Check your PYTHONPATH environment variable!
2974
2975- Python bytecode files (*.pyc and *.pyo) are not compatible between
2976releases.
2977
2978
2979Overview of Changes Since 1.6
2980-----------------------------
2981
2982There are many new modules (including brand new XML support through
2983the xml package, and i18n support through the gettext module); a list
2984of all new modules is included below. Lots of bugs have been fixed.
2985
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002986The process for making major new changes to the language has changed
2987since Python 1.6. Enhancements must now be documented by a Python
2988Enhancement Proposal (PEP) before they can be accepted.
2989
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002990There are several important syntax enhancements, described in more
2991detail below:
2992
2993 - Augmented assignment, e.g. x += 1
2994
2995 - List comprehensions, e.g. [x**2 for x in range(10)]
2996
2997 - Extended import statement, e.g. import Module as Name
2998
2999 - Extended print statement, e.g. print >> file, "Hello"
3000
3001Other important changes:
3002
3003 - Optional collection of cyclical garbage
3004
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003005Python Enhancement Proposal (PEP)
3006---------------------------------
3007
3008PEP stands for Python Enhancement Proposal. A PEP is a design
3009document providing information to the Python community, or describing
3010a new feature for Python. The PEP should provide a concise technical
3011specification of the feature and a rationale for the feature.
3012
3013We intend PEPs to be the primary mechanisms for proposing new
3014features, for collecting community input on an issue, and for
3015documenting the design decisions that have gone into Python. The PEP
3016author is responsible for building consensus within the community and
3017documenting dissenting opinions.
3018
3019The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003020
3021Augmented Assignment
3022--------------------
3023
3024This must have been the most-requested feature of the past years!
3025Eleven new assignment operators were added:
3026
Guido van Rossume905e952000-09-05 12:42:46 +00003027 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003028
3029For example,
3030
3031 A += B
3032
3033is similar to
3034
3035 A = A + B
3036
3037except that A is evaluated only once (relevant when A is something
3038like dict[index].attr).
3039
3040However, if A is a mutable object, A may be modified in place. Thus,
3041if A is a number or a string, A += B has the same effect as A = A+B
3042(except A is only evaluated once); but if a is a list, A += B has the
3043same effect as A.extend(B)!
3044
3045Classes and built-in object types can override the new operators in
3046order to implement the in-place behavior; the not-in-place behavior is
3047used automatically as a fallback when an object doesn't implement the
3048in-place behavior. For classes, the method name is derived from the
3049method name for the corresponding not-in-place operator by inserting
3050an 'i' in front of the name, e.g. __iadd__ implements in-place
3051__add__.
3052
3053Augmented assignment was implemented by Thomas Wouters.
3054
3055
3056List Comprehensions
3057-------------------
3058
3059This is a flexible new notation for lists whose elements are computed
3060from another list (or lists). The simplest form is:
3061
3062 [<expression> for <variable> in <sequence>]
3063
Guido van Rossum56db0952000-09-06 23:34:25 +00003064For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003065This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003066
3067You can also add a condition:
3068
3069 [<expression> for <variable> in <sequence> if <condition>]
3070
3071For example, [w for w in words if w == w.lower()] would yield the list
3072of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003073than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003074
3075You can also have nested for loops and more than one 'if' clause. For
3076example, here's a function that flattens a sequence of sequences::
3077
3078 def flatten(seq):
3079 return [x for subseq in seq for x in subseq]
3080
3081 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3082
3083This prints
3084
3085 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3086
3087List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003088Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003089
3090
3091Extended Import Statement
3092-------------------------
3093
3094Many people have asked for a way to import a module under a different
3095name. This can be accomplished like this:
3096
3097 import foo
3098 bar = foo
3099 del foo
3100
3101but this common idiom gets old quickly. A simple extension of the
3102import statement now allows this to be written as follows:
3103
3104 import foo as bar
3105
3106There's also a variant for 'from ... import':
3107
3108 from foo import bar as spam
3109
3110This also works with packages; e.g. you can write this:
3111
3112 import test.regrtest as regrtest
3113
3114Note that 'as' is not a new keyword -- it is recognized only in this
3115context (this is only possible because the syntax for the import
3116statement doesn't involve expressions).
3117
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003118Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003119
3120
3121Extended Print Statement
3122------------------------
3123
3124Easily the most controversial new feature, this extension to the print
3125statement adds an option to make the output go to a different file
3126than the default sys.stdout.
3127
3128For example, to write an error message to sys.stderr, you can now
3129write:
3130
3131 print >> sys.stderr, "Error: bad dog!"
3132
3133As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003134evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003135
3136 print >> None, "Hello world"
3137
3138is equivalent to
3139
3140 print "Hello world"
3141
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003142Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003143
3144
3145Optional Collection of Cyclical Garbage
3146---------------------------------------
3147
3148Python is now equipped with a garbage collector that can hunt down
3149cyclical references between Python objects. It's no replacement for
3150reference counting; in fact, it depends on the reference counts being
3151correct, and decides that a set of objects belong to a cycle if all
3152their reference counts can be accounted for from their references to
3153each other. This devious scheme was first proposed by Eric Tiedemann,
3154and brought to implementation by Neil Schemenauer.
3155
3156There's a module "gc" that lets you control some parameters of the
3157garbage collection. There's also an option to the configure script
3158that lets you enable or disable the garbage collection. In 2.0b1,
3159it's on by default, so that we (hopefully) can collect decent user
3160experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003161performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003162off by default in the final 2.0 release.
3163
3164
3165Smaller Changes
3166---------------
3167
3168A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3169map(None, seq1, seq2, ...) when the sequences have the same length;
3170i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3171the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003172zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003173
3174sys.version_info is a tuple (major, minor, micro, level, serial).
3175
3176Dictionaries have an odd new method, setdefault(key, default).
3177dict.setdefault(key, default) returns dict[key] if it exists; if not,
3178it sets dict[key] to default and returns that value. Thus:
3179
3180 dict.setdefault(key, []).append(item)
3181
3182does the same work as this common idiom:
3183
3184 if not dict.has_key(key):
3185 dict[key] = []
3186 dict[key].append(item)
3187
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003188There are two new variants of SyntaxError that are raised for
3189indentation-related errors: IndentationError and TabError.
3190
3191Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3192escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003193
3194The limits on the size of expressions and file in Python source code
3195have been raised from 2**16 to 2**32. Previous versions of Python
3196were limited because the maximum argument size the Python VM accepted
3197was 2**16. This limited the size of object constructor expressions,
3198e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3199limit was raised thanks to a patch by Charles Waldman that effectively
3200fixes the problem. It is now much more likely that you will be
3201limited by available memory than by an arbitrary limit in Python.
3202
3203The interpreter's maximum recursion depth can be modified by Python
3204programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3205limit is the maximum number of recursive calls that can be made by
3206Python code. The limit exists to prevent infinite recursion from
3207overflowing the C stack and causing a core dump. The default value is
32081000. The maximum safe value for a particular platform can be found
3209by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003210
3211New Modules and Packages
3212------------------------
3213
3214atexit - for registering functions to be called when Python exits.
3215
3216imputil - Greg Stein's alternative API for writing custom import
3217hooks.
3218
3219pyexpat - an interface to the Expat XML parser, contributed by Paul
3220Prescod.
3221
3222xml - a new package with XML support code organized (so far) in three
3223subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3224would fill a volume. There's a special feature whereby a
3225user-installed package named _xmlplus overrides the standard
3226xmlpackage; this is intended to give the XML SIG a hook to distribute
3227backwards-compatible updates to the standard xml package.
3228
3229webbrowser - a platform-independent API to launch a web browser.
3230
3231
Guido van Rossume905e952000-09-05 12:42:46 +00003232Changed Modules
3233---------------
3234
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003235array -- new methods for array objects: count, extend, index, pop, and
3236remove
3237
3238binascii -- new functions b2a_hex and a2b_hex that convert between
3239binary data and its hex representation
3240
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003241calendar -- Many new functions that support features including control
3242over which day of the week is the first day, returning strings instead
3243of printing them. Also new symbolic constants for days of week,
3244e.g. MONDAY, ..., SUNDAY.
3245
3246cgi -- FieldStorage objects have a getvalue method that works like a
3247dictionary's get method and returns the value attribute of the object.
3248
3249ConfigParser -- The parser object has new methods has_option,
3250remove_section, remove_option, set, and write. They allow the module
3251to be used for writing config files as well as reading them.
3252
3253ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003254optionally support the RFC 959 REST command.
3255
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003256gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003257
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003258httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3259the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003260
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003261locale -- implement getdefaultlocale for Win32 and Macintosh
3262
3263marshal -- no longer dumps core when marshaling deeply nested or
3264recursive data structures
3265
3266os -- new functions isatty, seteuid, setegid, setreuid, setregid
3267
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003268os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3269support under Unix.
3270
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003271os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003272
3273os.path -- fix semantics of os.path.commonprefix
3274
3275smtplib -- support for sending very long messages
3276
3277socket -- new function getfqdn()
3278
3279readline -- new functions to read, write and truncate history files.
3280The readline section of the library reference manual contains an
3281example.
3282
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003283select -- add interface to poll system call
3284
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003285shutil -- new copyfileobj function
3286
3287SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3288HTTP server.
3289
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003290Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003291
3292urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003293e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003294
3295whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003296
3297
3298Obsolete Modules
3299----------------
3300
3301None. However note that 1.6 made a whole slew of modules obsolete:
3302stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3303poly, zmod, strop, util, whatsound.
3304
3305
3306Changed, New, Obsolete Tools
3307----------------------------
3308
Tim Peters8b092332000-09-05 20:15:25 +00003309None.
Guido van Rossume905e952000-09-05 12:42:46 +00003310
3311
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003312C-level Changes
3313---------------
3314
3315Several cleanup jobs were carried out throughout the source code.
3316
3317All C code was converted to ANSI C; we got rid of all uses of the
3318Py_PROTO() macro, which makes the header files a lot more readable.
3319
3320Most of the portability hacks were moved to a new header file,
3321pyport.h; several other new header files were added and some old
3322header files were removed, in an attempt to create a more rational set
3323of header files. (Few of these ever need to be included explicitly;
3324they are all included by Python.h.)
3325
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003326Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003327and Win64, especially for the new Intel Itanium processor. Mick also
3328added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003329
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003330The C APIs to return an object's size have been update to consistently
3331use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3332previous versions, the abstract interfaces used PyXXX_Length and the
3333concrete interfaces used PyXXX_Size. The old names,
3334e.g. PyObject_Length, are still available for backwards compatibility
3335at the API level, but are deprecated.
3336
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003337The PyOS_CheckStack function has been implemented on Windows by
3338Fredrik Lundh. It prevents Python from failing with a stack overflow
3339on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003340
3341The GC changes resulted in creation of two new slots on object,
3342tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003343the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003344
3345The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003346C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003347
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003348PyErr_Format has been updated to automatically calculate the size of
3349the buffer needed to hold the formatted result string. This change
3350prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003351
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003352New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003353
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003354PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3355that are the same as their non-Ex counterparts except they take an
3356extra flag argument that tells them to close the file when done.
3357
3358XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003359
Tim Peters8b092332000-09-05 20:15:25 +00003360
3361Windows Changes
3362---------------
3363
3364New popen2/popen3/peopen4 in os module (see Changed Modules above).
3365
3366os.popen is much more usable on Windows 95 and 98. See Microsoft
3367Knowledge Base article Q150956. The Win9x workaround described there
3368is implemented by the new w9xpopen.exe helper in the root of your
3369Python installation. Note that Python uses this internally; it is not
3370a standalone program.
3371
3372Administrator privileges are no longer required to install Python
3373on Windows NT or Windows 2000. If you have administrator privileges,
3374Python's registry info will be written under HKEY_LOCAL_MACHINE.
3375Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003376under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003377uses of Python, but will prevent some advanced uses from working
3378(for example, running a Python script as an NT service, or possibly
3379from CGI).
3380
3381[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3382installer; instead, it installs the needed Tcl/Tk files directly in the
3383Python directory. If you already have a Tcl/Tk installation, this
3384wastes some disk space (about 4 Megs) but avoids problems with
3385conflicting Tcl/Tk installations, and makes it much easier for Python
3386to ensure that Tcl/Tk can find all its files.
3387
3388[This was new in 1.6] The Windows installer now installs by default in
3389\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3390
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003391
3392Updates to the changes between 1.5.2 and 1.6
3393--------------------------------------------
3394
3395The 1.6 NEWS file can't be changed after the release is done, so here
3396is some late-breaking news:
3397
3398New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3399and changes to getlocale() and setlocale().
3400
3401The new module is now enabled per default.
3402
3403It is not true that the encodings codecs cannot be used for normal
3404strings: the string.encode() (which is also present on 8-bit strings
3405!) allows using them for 8-bit strings too, e.g. to convert files from
3406cp1252 (Windows) to latin-1 or vice-versa.
3407
3408Japanese codecs are available from Tamito KAJIYAMA:
3409http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3410
3411
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003412======================================================================