blob: a0ae51e151611f5b07f0fa330ffc7627ac1ecadc [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
Anthony Baxter83888952002-04-23 02:11:05 +000067- The bsddb.*open functions can now take 'None' as a filename.
68 This will create a temporary in-memory bsddb that won't be
69 written to disk.
70
Martin v. Löwis06a83e92002-04-14 10:19:44 +000071- posix.mknod was added.
72
Martin v. Löwis2e64c342002-03-27 18:49:02 +000073- The locale module now exposes the C library's gettext interface.
74
Tim Petersfbf74f22002-03-14 19:06:01 +000075- A security hole ("double free") was found in zlib-1.1.3, a popular
76 third party compression library used by some Python modules. The
77 hole was quickly plugged in zlib-1.1.4, and the Windows build of
78 Python now ships with zlib-1.1.4.
79
Martin v. Löwis688357e2002-04-08 21:28:20 +000080- pwd, grp, and resource return enhanced tuples now, with symbolic
81 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000082
Martin v. Löwis99866332002-03-01 10:27:01 +000083- array.array is now a type object. A new format character
84 'u' indicates Py_UNICODE arrays. For those, .tounicode and
85 .fromunicode methods are available. Arrays now support __iadd__
86 and __imul__.
87
Neal Norwitze790eae2002-01-01 21:14:12 +000088- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000089 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
90 is called.
91
Tim Petersaf8446f2001-12-21 21:36:50 +000092Library
93
Guido van Rossum256705b2002-04-23 13:29:43 +000094- New Text.dump() method in Tkinter module.
95
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +000096- New distutils commands for building packagers were added to
97 support pkgtool on Solaris and swinstall on HP-UX.
98
99- distutils now has a new abstract binary packager base class
100 command/bdist_packager, which simplifies writing packagers.
101 This will hopefully provide the missing bits to encourage
102 people to submit more packagers, e.g. for Debian, FreeBSD
103 and other systems.
104
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000105- The UTF-16, -LE and -BE now raise a NotImplementedError
106 for all calls to .readline(). Previously, they used to just
107 produce garbage or fail with an encoding error -- UTF-16 is
108 a 2-byte encoding and the C lib's line reading APIs don't
109 work well with these.
110
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000111- compileall now supports quiet operation.
112
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000113- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
114 connections.
115
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000116- socket module: the SSL support was broken out of the main
117 _socket module C helper and placed into a new _ssl helper
118 which now gets imported by socket.py if available and working.
119
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000120- encodings package: added aliases for all supported IANA character
121 sets
122
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000123- ftplib: to safeguard the user's privacy, anonymous login will use
124 "anonymous@" as default password, rather than the real user and host
125 name.
126
Fred Drake36736122002-01-10 13:50:31 +0000127- webbrowser: tightened up the command passed to os.system() so that
128 arbitrary shell code can't be executed because a bogus URL was
129 passed in.
130
Tim Peters11bd9942002-02-01 00:52:29 +0000131- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000132 gettext.find an optional all argument. Translations will now fallback
133 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000134
Martin v. Löwis9668b932002-01-12 11:27:42 +0000135- distutils bdist commands now offer a --skip-build option.
136
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000137- warnings.warn now accepts a Warning instance as first argument.
138
Fred Drakefed7e852002-04-04 19:36:15 +0000139- The xml.sax.expatreader.ExpatParser class will no longer create
140 circular references by using itself as the locator that gets passed
141 to the content handler implementation. [SF bug #535474]
142
Tim Petersaf8446f2001-12-21 21:36:50 +0000143Tools/Demos
144
Marc-André Lemburg46260092002-04-04 16:17:11 +0000145- freeze.py now produces binaries which can import shared modules,
146 unlike before when this failed due to missing symbol exports in
147 the generated binary.
148
Tim Petersaf8446f2001-12-21 21:36:50 +0000149Build
150
Tim Peters639295f2002-04-21 07:30:30 +0000151- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
152 say how or when to configure it, or how to turn it off.
153
Martin v. Löwis1142de32002-03-29 16:28:31 +0000154- On Unix, a shared libpython2.3.so can be created with --enable-shared.
155
Tim Peters8deda702002-03-30 10:06:07 +0000156- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
157 preprocessor symbols were eliminated. The internal decisions they
158 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000159
Tim Petersaf8446f2001-12-21 21:36:50 +0000160C API
161
Neil Schemenauer9344b142002-04-12 23:00:08 +0000162- The type of tp_free has been changed from "void (*)(PyObject *)" to
163 "void (*)(void *)".
164
165- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
166
Guido van Rossum0986d822002-04-08 01:38:42 +0000167- A type can now inherit its metatype from its base type. Previously,
168 when PyType_Ready() was called, if ob_type was found to be NULL, it
169 was always set to &PyType_Type; now it is set to base->ob_type,
170 where base is tp_base, defaulting to &PyObject_Type.
171
172- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
173
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000174- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
175 functions will be allocated using pymalloc if it is enabled. These
176 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
177 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
178 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
179 PyCore_* family of APIs have been removed.
180
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000181- The "u#" parser marker will now pass through Unicode object as-is
182 without going through the buffer API.
183
Martin v. Löwis7198a522002-01-01 19:59:11 +0000184- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
185
Tim Peters10a3bb52001-12-25 19:07:38 +0000186- An old #define of ANY as void has been removed from pyport.h. This
187 hasn't been used since Python's pre-ANSI days, and the #define has
188 been marked as obsolete since then. SF bug 495548 says it created
189 conflicts with other packages, so keeping it around wasn't harmless.
190
Tim Petersaf8446f2001-12-21 21:36:50 +0000191- Because Python's magic number scheme broke on January 1st, we decided
192 to stop Python development. Thanks for all the fish!
193
Tim Petersfb05db22002-03-11 00:24:00 +0000194- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000195 scheme to a new one. See Python/import.c for details.
196
Tim Petersaf8446f2001-12-21 21:36:50 +0000197New platforms
198
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000199- GNU/Hurd is now supported.
200
Tim Petersaf8446f2001-12-21 21:36:50 +0000201Tests
202
203Windows
204
Tim Peters08e72952002-04-16 20:48:01 +0000205- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
206 of that has been fixed in the installer (disabled Wise's "delete in-
207 use files" uninstall option).
208
Guido van Rossum181e41a2002-04-06 00:23:25 +0000209- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
210
Tim Peters33187922002-04-04 20:02:04 +0000211- The installer now installs Start menu shortcuts under (the local
212 equivalent of) "All Users" when doing an Admin install.
213
Tim Petersfb05db22002-03-11 00:24:00 +0000214- file.truncate([newsize]) now works on Windows for all newsize values.
215 It used to fail if newsize didn't fit in 32 bits, reflecting a
216 limitation of MS _chsize (which is no longer used).
217
Tim Petersab034fa2002-02-01 11:27:43 +0000218- os.waitpid() is now implemented for Windows, and can be used to block
219 until a specified process exits. This is similar to, but not exactly
220 the same as, os.waitpid() on POSIX systems. If you're waiting for
221 a specific process whose pid was obtained from one of the spawn()
222 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000223 See the docs for details. The docs were changed to clarify that
224 spawn functions return, and waitpid requires, a process handle on
225 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000226
Tim Peters11bd9942002-02-01 00:52:29 +0000227- New tempfile.TemporaryFile implementation for Windows: this doesn't
228 need a TemproraryFileWrapper wrapper anymore, and should be immune
229 to a nasty problem: before 2.3, if you got a temp file on Windows, it
230 got wrapped in an object whose close() method first closed the
231 underlying file, then deleted the file. This usually worked fine.
232 However, the spawn family of functions on Windows create (at a low C
233 level) the same set of open files in the spawned process Q as were
234 open in the spawning process P. If a temp file f was among them, then
235 doing f.close() in P first closed P's C-level file handle on f, but Q's
236 C-level file handle on f remained open, so the attempt in P to delete f
237 blew up with a "Permission denied" error (Windows doesn't allow
238 deleting open files). This was surprising, subtle, and difficult to
239 work around.
240
241- The os module now exports all the symbolic constants usable with the
242 low-level os.open() on Windows: the new constants in 2.3 are
243 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
244 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
245 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
246 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
247 (so specify both if you want both; note that neither is useful unless
248 specified with O_CREAT too).
249
Tim Petersaf8446f2001-12-21 21:36:50 +0000250Mac
251
252
Tim Peters909c0912001-12-14 23:16:18 +0000253What's New in Python 2.2 final?
254Release date: 21-Dec-2001
255===============================
256
257Type/class unification and new-style classes
258
Barry Warsaw52acb492001-12-21 20:04:22 +0000259- pickle.py, cPickle: allow pickling instances of new-style classes
260 with a custom metaclass.
261
Tim Peters909c0912001-12-14 23:16:18 +0000262Core and builtins
263
Barry Warsaw52acb492001-12-21 20:04:22 +0000264- weakref proxy object: when comparing, unwrap both arguments if both
265 are proxies.
266
Tim Peters909c0912001-12-14 23:16:18 +0000267Extension modules
268
Barry Warsaw52acb492001-12-21 20:04:22 +0000269- binascii.b2a_base64(): fix a potential buffer overrun when encoding
270 very short strings.
271
272- cPickle: the obscure "fast" mode was suspected of causing stack
273 overflows on the Mac. Hopefully fixed this by setting the recursion
274 limit much smaller. If the limit is too low (it only affects
275 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
276 when compiling cPickle.c (or in pyconfig.h).
277
Tim Peters909c0912001-12-14 23:16:18 +0000278Library
279
Barry Warsaw52acb492001-12-21 20:04:22 +0000280- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
281 close or delete time).
282
283- rfc822.py: fixed a bug where the address '<>' was converted to None
284 instead of an empty string (also fixes the email.Utils module).
285
286- xmlrpclib.py: version 1.0.0; uses precision for doubles.
287
288- test suite: the pickle and cPickle tests were not executing any code
289 when run from the standard regresssion test.
290
Tim Peters909c0912001-12-14 23:16:18 +0000291Tools/Demos
292
293Build
294
295C API
296
297New platforms
298
299Tests
300
301Windows
302
Barry Warsaw52acb492001-12-21 20:04:22 +0000303- distutils package: fixed broken Windows installers (bdist_wininst).
304
305- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
306 instances are deleted at process exit time.
307
308- socket.py: prevent mysterious warnings when socket instances are
309 deleted at process exit time.
310
311- posixmodule.c: fix a Windows crash with stat() of a filename ending
312 in backslash.
313
Tim Peters909c0912001-12-14 23:16:18 +0000314Mac
315
Barry Warsaw52acb492001-12-21 20:04:22 +0000316- The Carbon toolbox modules have been upgraded to Universal Headers
317 3.4, and experimental CoreGraphics and CarbonEvents modules have
318 been added. All only for framework-enabled MacOSX.
319
Tim Peters909c0912001-12-14 23:16:18 +0000320
Tim Peters6272dfd2001-12-13 19:34:00 +0000321What's New in Python 2.2c1?
322Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000323===========================
324
325Type/class unification and new-style classes
326
Barry Warsaw06557452001-12-14 20:47:12 +0000327- Guido's tutorial introduction to the new type/class features has
328 been extensively updated. See
329
330 http://www.python.org/2.2/descrintro.html
331
332 That remains the primary documentation in this area.
333
Guido van Rossum33bab012001-12-05 22:45:48 +0000334- Fixed a leak: instance variables declared with __slots__ were never
335 deleted!
336
Guido van Rossum4b800852001-12-03 00:54:52 +0000337- The "delete attribute" method of descriptor objects is called
338 __delete__, not __del__. In previous releases, it was mistakenly
339 called __del__, which created an unfortunate overloading condition
340 with finalizers. (The "get attribute" and "set attribute" methods
341 are still called __get__ and __set__, respectively.)
342
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000343- Some subtle issues with the super built-in were fixed:
344
345 (a) When super itself is subclassed, its __get__ method would still
346 return an instance of the base class (i.e., of super).
347
348 (b) super(C, C()).__class__ would return C rather than super. This
349 is confusing. To fix this, I decided to change the semantics of
350 super so that it only applies to code attributes, not to data
351 attributes. After all, overriding data attributes is not
352 supported anyway.
353
354 (c) The __get__ method didn't check whether the argument was an
355 instance of the type used in creation of the super instance.
356
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000357- Previously, hash() of an instance of a subclass of a mutable type
358 (list or dictionary) would return some value, rather than raising
359 TypeError. This has been fixed. Also, directly calling
360 dict.__hash__ and list.__hash__ now raises the same TypeError
361 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000362
Guido van Rossumd331cb52001-12-05 19:46:42 +0000363- New-style objects now support deleting their __dict__. This is for
364 all intents and purposes equivalent to assigning a brand new empty
365 dictionary, but saves space if the object is not used further.
366
Tim Petersb3c9af12001-11-17 00:21:57 +0000367Core and builtins
368
Tim Peters3caca232001-12-06 06:23:26 +0000369- -Qnew now works as documented in PEP 238: when -Qnew is passed on
370 the command line, all occurrences of "/" use true division instead
371 of classic division. See the PEP for details. Note that "all"
372 means all instances in library and 3rd-party modules, as well as in
373 your own code. As the PEP says, -Qnew is intended for use only in
374 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000375 Note that test_coercion.py in the standard Python test suite fails
376 under -Qnew; this is expected, and won't be repaired until true
377 division becomes the default (in the meantime, test_coercion is
378 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000379
Fred Drake6c01e252001-12-14 17:08:12 +0000380- complex() now only allows the first argument to be a string
381 argument, and raises TypeError if either the second arg is a string
382 or if the second arg is specified when the first is a string.
383
Tim Petersb3c9af12001-11-17 00:21:57 +0000384Extension modules
385
Martin v. Löwis560da622001-11-24 09:24:51 +0000386- gc.get_referents was renamed to gc.get_referrers.
387
Tim Petersb3c9af12001-11-17 00:21:57 +0000388Library
389
Tim Peters25059d32001-12-07 20:35:43 +0000390- Functions in the os.spawn() family now release the global interpreter
391 lock around calling the platform spawn. They should always have done
392 this, but did not before 2.2c1. Multithreaded programs calling
393 an os.spawn function with P_WAIT will no longer block all Python threads
394 until the spawned program completes. It's possible that some programs
395 relies on blocking, although more likely by accident than by design.
396
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000397- webbrowser defaults to netscape.exe on OS/2 now.
398
Martin v. Löwis652e1912001-11-25 14:50:56 +0000399- Tix.ResizeHandle exposes detach_widget, hide, and show.
400
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000401- The charset alias windows_1252 has been added.
402
Barry Warsaw06557452001-12-14 20:47:12 +0000403- types.StringTypes is a tuple containing the defined string types;
404 usually this will be (str, unicode), but if Python was compiled
405 without Unicode support it will be just (str,).
406
407- The pulldom and minidom modules were synchronized to PyXML.
408
Tim Petersb3c9af12001-11-17 00:21:57 +0000409Tools/Demos
410
Barry Warsaw06557452001-12-14 20:47:12 +0000411- A new script called Tools/scripts/google.py was added, which fires
412 off a search on Google.
413
Tim Petersb3c9af12001-11-17 00:21:57 +0000414Build
415
Barry Warsaw06557452001-12-14 20:47:12 +0000416- Note that release builds of Python should arrange to define the
417 preprocessor symbol NDEBUG on the command line (or equivalent).
418 In the 2.2 pre-release series we tried to define this by magic in
419 Python.h instead, but it proved to cause problems for extension
420 authors. The Unix, Windows and Mac builds now all define NDEBUG in
421 release builds via cmdline (or equivalent) instead. Ports to
422 other platforms should do likewise.
423
Jack Jansen1999ef42001-12-06 21:47:20 +0000424- It is no longer necessary to use --with-suffix when building on a
425 case-insensitive file system (such as Mac OS X HFS+). In the build
426 directory an extension is used, but not in the installed python.
427
Tim Petersb3c9af12001-11-17 00:21:57 +0000428C API
429
Tim Petersf582b822001-12-11 18:51:08 +0000430- New function PyDict_MergeFromSeq2() exposes the builtin dict
431 constructor's logic for updating a dictionary from an iterable object
432 producing key-value pairs.
433
Tim Peterscffed4b2001-11-29 03:26:37 +0000434- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000435 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000436 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
437 dump core in some bad cases. This has been repaired. As a result,
438 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
439 previously went unchallenged.
440
Tim Petersb3c9af12001-11-17 00:21:57 +0000441New platforms
442
443Tests
444
445Windows
446
447Mac
448
Jack Jansenffa260f2001-12-06 21:14:00 +0000449- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
450 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000451
Barry Warsaw06557452001-12-14 20:47:12 +0000452- Changed logic for finding python home in Mac OS X framework Pythons.
453 Now sys.executable points to the executable again, in stead of to
454 the shared library. The latter is used only for locating the python
455 home.
456
457
Tim Peters84362bc2001-10-19 17:55:30 +0000458What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000459Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000460===========================
461
462Type/class unification and new-style classes
463
Guido van Rossum3d27df02001-11-15 20:27:54 +0000464- Multiple inheritance mixing new-style and classic classes in the
465 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000466
467 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000468 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000469
470 The MRO (method resolution order) for each base class is respected
471 according to its kind, but the MRO for the derived class is computed
472 using new-style MRO rules if any base clase is a new-style class.
473 This needs to be documented.
474
Tim Petersa427a2b2001-10-29 22:25:45 +0000475- The new builtin dictionary() constructor, and dictionary type, have
476 been renamed to dict. This reflects a decade of common usage.
477
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000478- dict() now accepts an iterable object producing 2-sequences. For
479 example, dict(d.items()) == d for any dictionary d. The argument,
480 and the elements of the argument, can be any iterable objects.
481
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000482- New-style classes can now have a __del__ method, which is called
483 when the instance is deleted (just like for classic classes).
484
Guido van Rossum12d955c2001-10-26 14:56:06 +0000485- Assignment to object.__dict__ is now possible, for objects that are
486 instances of new-style classes that have a __dict__ (unless the base
487 class forbids it).
488
Guido van Rossumc8e56452001-10-22 00:43:43 +0000489- Methods of built-in types now properly check for keyword arguments
490 (formerly these were silently ignored). The only built-in methods
491 that take keyword arguments are __call__, __init__ and __new__.
492
Guido van Rossum86443212001-10-27 22:28:54 +0000493- The socket function has been converted to a type; see below.
494
Tim Peters84362bc2001-10-19 17:55:30 +0000495Core and builtins
496
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000497- Assignment to __debug__ raises SyntaxError at compile-time. This
498 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000499 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000500
Guido van Rossum12d955c2001-10-26 14:56:06 +0000501- Clarified the error messages for unsupported operands to an operator
502 (like 1 + '').
503
Tim Peters84362bc2001-10-19 17:55:30 +0000504Extension modules
505
Tim Peters5ebfd362001-11-13 23:11:19 +0000506- mmap has a new keyword argument, "access", allowing a uniform way for
507 both Windows and Unix users to create read-only, write-through and
508 copy-on-write memory mappings. This was previously possible only on
509 Unix. A new keyword argument was required to support this in a
510 uniform way because the mmap() signuatures had diverged across
511 platforms. Thanks to Jay T Miller for repairing this!
512
Tim Peters169ded02001-11-03 19:57:21 +0000513- By default, the gc.garbage list now contains only those instances in
514 unreachable cycles that have __del__ methods; in 2.1 it contained all
515 instances in unreachable cycles. "Instances" here has been generalized
516 to include instances of both new-style and old-style classes.
517
Guido van Rossum12d955c2001-10-26 14:56:06 +0000518- The socket module defines a new method for socket objects,
519 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000520 send() until all data has been sent. Also, the socket function has
521 been converted to a subclassable type, like list and tuple (etc.)
522 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000523
524- Various bugfixes to the curses module. There is now a test suite
525 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000526
Guido van Rossum692adf12001-10-30 03:03:03 +0000527- binascii.b2a_base64 no longer places an arbitrary restriction of 57
528 bytes on its input.
529
Tim Peters84362bc2001-10-19 17:55:30 +0000530Library
531
Tim Peters5ebfd362001-11-13 23:11:19 +0000532- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000533 convenience function.
534
Tim Peters75335872001-11-03 19:35:43 +0000535- Symbolic group names in regular expressions must be unique. For
536 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
537 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000538 Python 2.2 detects this error at regexp compilation time;
539 previously, the error went undetected, and results were
540 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
541 pattern.subn() methods have been rewritten in C. Also, an
542 experimental function/method finditer() has been added, which works
543 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000544
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000545- Tix exposes more commands through the classes DirSelectBox,
546 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
547 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
548 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
549
Tim Peters98791af2001-10-23 01:59:54 +0000550- Traceback objects are now scanned by cyclic garbage collection, so
551 cycles created by casual use of sys.exc_info() no longer cause
552 permanent memory leaks (provided garbage collection is enabled).
553
Guido van Rossum49192142001-10-24 20:51:44 +0000554- os.extsep -- a new variable needed by the RISCOS support. It is the
555 separator used by extensions, and is '.' on all platforms except
556 RISCOS, where it is '/'. There is no need to use this variable
557 unless you have a masochistic desire to port your code to RISCOS.
558
Barry Warsaw012852b2001-11-16 16:17:27 +0000559- mimetypes.py has optional support for non-standard, but commonly
560 found types. guess_type() and guess_extension() now accept an
561 optional `strict' flag, defaulting to true, which controls whether
562 recognize non-standard types or not. A few non-standard types we
563 know about have been added. Also, when run as a script, there are
564 new -l and -e options.
565
566- statcache is now deprecated.
567
568- email.Utils.formatdate() now produces the preferred RFC 2822 style
569 dates with numeric timezones (it used to produce obsolete dates
570 hard coded to "GMT" timezone). An optional `localtime' flag is
571 added to produce dates in the local timezone, with daylight savings
572 time properly taken into account.
573
574- In pickle and cPickle, instead of masking errors in load() by
575 transforming them into SystemError, we let the original exception
576 propagate out. Also, implement support for __safe_for_unpickling__
577 in pickle, as it already was supported in cPickle.
578
Tim Peters84362bc2001-10-19 17:55:30 +0000579Tools/Demos
580
581Build
582
Barry Warsaw012852b2001-11-16 16:17:27 +0000583- The dbm module is built using libdb1 if available. The bsddb module
584 is built with libdb3 if available.
585
586- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
587
Tim Peters84362bc2001-10-19 17:55:30 +0000588C API
589
Tim Peters1fc240e2001-10-26 05:06:50 +0000590- New function PySequence_Fast_GET_SIZE() returns the size of a non-
591 NULL result from PySequence_Fast(), more quickly than calling
592 PySequence_Size().
593
Barry Warsaw012852b2001-11-16 16:17:27 +0000594- New argument unpacking function PyArg_UnpackTuple() added.
595
596- New functions PyObject_CallFunctionObjArgs() and
597 PyObject_CallMethodObjArgs() have been added to make it more
598 convenient and efficient to call functions and methods from C.
599
600- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
601 possible that this will propagate errors it didn't before.
602
603- New function PyObject_CheckReadBuffer(), which returns true if its
604 argument supports the single-segment readable buffer interface.
605
Tim Peters84362bc2001-10-19 17:55:30 +0000606New platforms
607
Guido van Rossum86443212001-10-27 22:28:54 +0000608- We've finally confirmed that this release builds on HP-UX 11.00,
609 *with* threads, and passes the test suite.
610
Tim Peters7a33d8b2001-11-05 02:51:07 +0000611- Thanks to a series of patches from Michael Muller, Python may build
612 again under OS/2 Visual Age C++.
613
Guido van Rossum49192142001-10-24 20:51:44 +0000614- Updated RISCOS port by Dietmar Schwertberger.
615
Tim Peters84362bc2001-10-19 17:55:30 +0000616Tests
617
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000618- Added a test script for the curses module. It isn't run automatically;
619 regrtest.py must be run with '-u curses' to enable it.
620
Tim Peters84362bc2001-10-19 17:55:30 +0000621Windows
622
Barry Warsaw012852b2001-11-16 16:17:27 +0000623Mac
624
625- PythonScript has been moved to unsupported and is slated to be
626 removed completely in the next release.
627
628- It should now be possible to build applets that work on both OS9 and
629 OSX.
630
631- The core is now linked with CoreServices not Carbon; as a side
632 result, default 8bit encoding on OSX is now ASCII.
633
634- Python should now build on OSX 10.1.1
635
Tim Peters84362bc2001-10-19 17:55:30 +0000636
Tim Petersabf925f2001-09-28 21:53:42 +0000637What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000638Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000639===========================
640
641Type/class unification and new-style classes
642
Guido van Rossum687ae002001-10-15 22:03:32 +0000643- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000644 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000645 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000646 remains: the __dict__ of a new-style class is a read-only proxy; you
647 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000648 __defined__ attribute of new-style types no longer exists, for lack
649 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000650 future a __cache__ may be resurrected with a similar function, if I
651 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000652
Tim Peters1c9ca872001-10-04 06:43:12 +0000653- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
654 always returned None, even when there was a class docstring).
655
656- doctest now finds and runs docstrings attached to new-style classes,
657 class methods, static methods, and properties.
658
Guido van Rossum9074ef62001-10-16 21:34:49 +0000659Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000660
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000661- A very subtle syntactical pitfall in list comprehensions was fixed.
662 For example: [a+b for a in 'abc', for b in 'def']. The comma in
663 this example is a mistake. Previously, this would silently let 'a'
664 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
665 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
666 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
667 Note that [a for a in <singleton>] is a convoluted way to say
668 [<singleton>] anyway, so it's not like any expressiveness is lost.
669
Guido van Rossum9074ef62001-10-16 21:34:49 +0000670- getattr(obj, name, default) now only catches AttributeError, as
671 documented, rather than returning the default value for all
672 exceptions (which could mask bugs in a __getattr__ hook, for
673 example).
674
Fred Drakecb7a6b52001-10-22 18:41:51 +0000675- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000676 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000677 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000678 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000679
Guido van Rossum1c486092001-10-19 02:05:35 +0000680- unicode(obj) now behaves more like str(obj), accepting arbitrary
681 objects, and calling a __unicode__ method if it exists.
682 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000683 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000684
Barry Warsawf6fb1712001-10-19 05:35:40 +0000685- isinstance() now allows any object as the first argument and a
686 class, a type or something with a __bases__ tuple attribute for the
687 second argument. The second argument may also be a tuple of a
688 class, type, or something with __bases__, in which case isinstance()
689 will return true if the first argument is an instance of any of the
690 things contained in the second argument tuple. E.g.
691
692 isinstance(x, (A, B))
693
694 returns true if x is an instance of A or B.
695
Guido van Rossum9074ef62001-10-16 21:34:49 +0000696Extension modules
697
698- thread.start_new_thread() now returns the thread ID (previously None).
699
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000700- binascii has now two quopri support functions, a2b_qp and b2a_qp.
701
Guido van Rossumc524d952001-10-19 01:31:59 +0000702- readline now supports setting the startup_hook and the
703 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000704
Guido van Rossumc524d952001-10-19 01:31:59 +0000705- os and posix supports chroot(), setgroups() and unsetenv() where
706 available. The stat(), fstat(), statvfs() and fstatvfs() functions
707 now return "pseudo-sequences" -- the various fields can now be
708 accessed as attributes (e.g. os.stat("/").st_mtime) but for
709 backwards compatibility they also behave as a fixed-length sequence.
710 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000711 attributes.
712
713- time: localtime(), gmtime() and strptime() now return a
714 pseudo-sequence similar to the os.stat() return value, with
715 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000716
Guido van Rossum9074ef62001-10-16 21:34:49 +0000717- Decompression objects in the zlib module now accept an optional
718 second parameter to decompress() that specifies the maximum amount
719 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000720
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000721- optional SSL support in the socket module now exports OpenSSL
722 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
723 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000724 automatically seed its PRNG. Also, the keyfile and certfile
725 arguments to socket.ssl() are now optional.
726
727- posixmodule (and by extension, the os module on POSIX platforms) now
728 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000729
Guido van Rossum9074ef62001-10-16 21:34:49 +0000730Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000731
Tim Peters7402f792001-10-02 03:53:41 +0000732- doctest now excludes functions and classes not defined by the module
733 being tested, thanks to Tim Hochberg.
734
Fred Drakecb7a6b52001-10-22 18:41:51 +0000735- HotShot, a new profiler implemented using a C-based callback, has
736 been added. This substantially reduces the overhead of profiling,
737 but it is still quite preliminary. Support modules and
738 documentation will be added in upcoming releases (before 2.2 final).
739
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000740- profile now produces correct output in situations where an exception
741 raised in Python is cleared by C code (e.g. hasattr()). This used
742 to cause wrong output, including spurious claims of recursive
743 functions and attribution of time spent to the wrong function.
744
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000745 The code and documentation for the derived OldProfile and HotProfile
746 profiling classes was removed. The code hasn't worked for years (if
747 you tried to use them, they raised exceptions). OldProfile
748 intended to reproduce the behavior of the profiler Python used more
749 than 7 years ago, and isn't interesting anymore. HotProfile intended
750 to provide a faster profiler (but producing less information), and
751 that's a worthy goal we intend to meet via a different approach (but
752 without losing information).
753
Tim Peterscce092d2001-10-09 05:31:56 +0000754- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000755 a much better system-specific calibration constant. The constant can
756 now be specified in an instance constructor, or as a Profile class or
757 instance variable, instead of by editing profile.py's source code.
758 Calibration must still be done manually (see the docs for the profile
759 module).
760
761 Note that Profile.calibrate() must be overriden by subclasses.
762 Improving the accuracy required exploiting detailed knowledge of
763 profiler internals; the earlier method abstracted away the details
764 and measured a simplified model instead, but consequently computed
765 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000766
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000767- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000768 which indicates whether output is intended for the header 'Q'
769 encoding.
770
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000771- The SocketServer.ThreadingMixIn class now closes the request after
772 finish_request() returns. (Not when it errors out though.)
773
Barry Warsawf6fb1712001-10-19 05:35:40 +0000774- The nntplib module's NNTP.body() method has grown a `file' argument
775 to allow saving the message body to a file.
776
777- The email package has added a class email.Parser.HeaderParser which
778 only parses headers and does not recurse into the message's body.
779 Also, the module/class MIMEAudio has been added for representing
780 audio data (contributed by Anthony Baxter).
781
782- ftplib should be able to handle files > 2GB.
783
784- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
785 ON, and OFF.
786
Fred Drakecb7a6b52001-10-22 18:41:51 +0000787- xml.dom.minidom NodeList objects now support the length attribute
788 and item() method as required by the DOM specifications.
789
Guido van Rossumed554f62001-10-02 23:15:37 +0000790Tools/Demos
791
792- Demo/dns was removed. It no longer serves any purpose; a package
793 derived from it is now maintained by Anthony Baxter, see
794 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000795
Barry Warsawf6fb1712001-10-19 05:35:40 +0000796- The freeze tool has been made more robust, and two new options have
797 been added: -X and -E.
798
Tim Petersabf925f2001-09-28 21:53:42 +0000799Build
800
Barry Warsawf6fb1712001-10-19 05:35:40 +0000801- configure will use CXX in LINKCC if CXX is used to build main() and
802 the system requires to link a C++ main using the C++ compiler.
803
Tim Petersabf925f2001-09-28 21:53:42 +0000804C API
805
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000806- The documentation for the tp_compare slot is updated to require that
807 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
808 not correct. This is not yet enforced but will be enforced in
809 Python 2.3; even later, we may use -2 to indicate errors and +2 for
810 "NotImplemented". Right now, -1 should be used for an error return.
811
Tim Petersd38b1c72001-09-30 05:09:37 +0000812- PyLong_AsLongLong() now accepts int (as well as long) arguments.
813 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
814 as long) arguments.
815
Guido van Rossum3c288632001-10-16 21:13:49 +0000816- PyThread_start_new_thread() now returns a long int giving the thread
817 ID, if one can be calculated; it returns -1 for error, 0 if no
818 thread ID is calculated (this is an incompatible change, but only
819 the thread module used this API). This code has only really been
820 tested on Linux and Windows; other platforms please beware (and
821 report any bugs or strange behavior).
822
Guido van Rossum1c486092001-10-19 02:05:35 +0000823- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
824 input.
825
Tim Petersabf925f2001-09-28 21:53:42 +0000826New platforms
827
828Tests
829
830Windows
831
Tim Peters04cf1d32001-10-09 22:39:40 +0000832- Installer: If you install IDLE, and don't disable file-extension
833 registration, a new "Edit with IDLE" context (right-click) menu entry
834 is created for .py and .pyw files.
835
Tim Peters1ce3cf72001-10-01 17:58:40 +0000836- The signal module now supports SIGBREAK on Windows, thanks to Steven
837 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
838 action remains to call Win32 ExitProcess(). This can be changed via
839 signal.signal(). For example:
840
841 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
842 # (SIGINT) behavior.
843 import signal
844 signal.signal(signal.SIGBREAK,
845 signal.default_int_handler)
846
847 try:
848 while 1:
849 pass
850 except KeyboardInterrupt:
851 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
852 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
853 # program without the possibility for any Python-level cleanup).
854 print "Clean exit"
855
Tim Petersabf925f2001-09-28 21:53:42 +0000856
Tim Petersb07352e2001-09-08 01:25:47 +0000857What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000858Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000859===========================
860
Guido van Rossum808eea72001-09-25 04:15:41 +0000861Type/class unification and new-style classes
862
863- pydoc and inspect are now aware of new-style classes;
864 e.g. help(list) at the interactive prompt now shows proper
865 documentation for all operations on list objects.
866
867- Applications using Jim Fulton's ExtensionClass module can now safely
868 be used with Python 2.2. In particular, Zope 2.4.1 now works with
869 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
870 examples also work again. It is hoped that Gtk and Boost also work
871 with 2.2a4 and beyond. (If you can confirm this, please write
872 webmaster@python.org; if there are still problems, please open a bug
873 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000874
Tim Peters66c1a522001-09-24 21:17:50 +0000875- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
876 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
877 in the constructed property object. fget, fset and fdel weren't
878 discoverable from Python in 2.2a3. __doc__ is new, and allows to
879 associate a docstring with a property.
880
Guido van Rossum808eea72001-09-25 04:15:41 +0000881- Comparison overloading is now more completely implemented. For
882 example, a str subclass instance can properly be compared to a str
883 instance, and it can properly overload comparison. Ditto for most
884 other built-in object types.
885
886- The repr() of new-style classes has changed; instead of <type
887 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
888 *except* for built-in types, which are still rendered as <type
889 'Foo'> (to avoid upsetting existing code that might parse or
890 otherwise rely on repr() of certain type objects).
891
892- The repr() of new-style objects is now always <Foo object at XXX>;
893 previously, it was sometimes <Foo instance at XXX>.
894
895- For new-style classes, what was previously called __getattr__ is now
896 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000897 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000898 one in classic classes is defined which is called only if regular
899 attribute access raises AttributeError; to catch *all* attribute
900 access, you can use __getattribute__ (for new-style classes). If
901 both are defined, __getattribute__ is called first, and if it raises
902 AttributeError, __getattr__ is called.
903
904- The __class__ attribute of new-style objects can be assigned to.
905 The new class must have the same C-level object layout as the old
906 class.
907
908- The builtin file type can be subclassed now. In the usual pattern,
909 "file" is the name of the builtin type, and file() is a new builtin
910 constructor, with the same signature as the builtin open() function.
911 file() is now the preferred way to open a file.
912
913- Previously, __new__ would only see sequential arguments passed to
914 the type in a constructor call; __init__ would see both sequential
915 and keyword arguments. This made no sense whatsoever any more, so
916 now both __new__ and __init__ see all arguments.
917
918- Previously, hash() applied to an instance of a subclass of str or
919 unicode always returned 0. This has been repaired.
920
921- Previously, an operation on an instance of a subclass of an
922 immutable type (int, long, float, complex, tuple, str, unicode),
923 where the subtype didn't override the operation (and so the
924 operation was handled by the builtin type), could return that
925 instance instead a value of the base type. For example, if s was of
926 a str sublass type, s[:] returned s as-is. Now it returns a str
927 with the same value as s.
928
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000929- Provisional support for pickling new-style objects has been added.
930
Guido van Rossum808eea72001-09-25 04:15:41 +0000931Core
932
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000933- file.writelines() now accepts any iterable object producing strings.
934
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000935- PyUnicode_FromEncodedObject() now works very much like
936 PyObject_Str(obj) in that it tries to use __str__/tp_str
937 on the object if the object is not a string or buffer. This
938 makes unicode() behave like str() when applied to non-string/buffer
939 objects.
940
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000941- PyFile_WriteObject now passes Unicode objects to the file's write
942 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000943 of a print statement must support Unicode objects, i.e. they must
944 at least convert them into ASCII strings.
945
Guido van Rossum624c8af2001-09-18 15:21:04 +0000946- Thread scheduling on Solaris should be improved; it is no longer
947 necessary to insert a small sleep at the start of a thread in order
948 to let other runnable threads be scheduled.
949
Tim Petersb07352e2001-09-08 01:25:47 +0000950Library
951
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000952- StringIO.StringIO instances and cStringIO.StringIO instances support
953 read character buffer compatible objects for their .write() methods.
954 These objects are converted to strings and then handled as such
955 by the instances.
956
Barry Warsaw2f600732001-09-24 04:28:10 +0000957- The "email" package has been added. This is basically a port of the
958 mimelib package <http://sf.net/projects/mimelib> with API changes
959 and some implementations updated to use iterators and generators.
960
Tim Peters8a9c2842001-09-22 21:30:22 +0000961- difflib.ndiff() and difflib.Differ.compare() are generators now. This
962 restores the ability of Tools/scripts/ndiff.py to start producing output
963 before the entire comparison is complete.
964
Barry Warsaw58b072d2001-09-22 04:44:21 +0000965- StringIO.StringIO instances and cStringIO.StringIO instances support
966 iteration just like file objects (i.e. their .readline() method is
967 called for each iteration until it returns an empty string).
968
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000969- The codecs module has grown four new helper APIs to access
970 builtin codecs: getencoder(), getdecoder(), getreader(),
971 getwriter().
972
Guido van Rossum624c8af2001-09-18 15:21:04 +0000973- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
974 simplifies writing XML RPC servers.
975
Barry Warsaw647d5e82001-09-28 17:01:02 +0000976- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000977 after interpretation of symbolic links. On non-Unix systems, this
978 is an alias for os.path.abspath().
979
Tim Peters16a77ad2001-09-08 04:00:12 +0000980- operator.indexOf() (PySequence_Index() in the C API) now works with any
981 iterable object.
982
Guido van Rossum624c8af2001-09-18 15:21:04 +0000983- smtplib now supports various authentication and security features of
984 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000985
Guido van Rossum624c8af2001-09-18 15:21:04 +0000986- hmac: a new module implementing keyed hashing for message
987 authentication.
988
989- mimetypes now recognizes more extensions and file types. At the
990 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000991
Guido van Rossum624c8af2001-09-18 15:21:04 +0000992- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000993 Python 2.2 bytecode generation. It has also been promoted from a
994 Tool to a standard library package. (Tools/compiler still exists as
995 a sample driver.)
996
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000997Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000998
Tim Petersb07352e2001-09-08 01:25:47 +0000999Build
1000
Guido van Rossum624c8af2001-09-18 15:21:04 +00001001- Large file support (LFS) is now automatic when the platform supports
1002 it; no more manual configuration tweaks are needed. On Linux, at
1003 least, it's possible to have a system whose C library supports large
1004 files but whose kernel doesn't; in this case, large file support is
1005 still enabled but doesn't do you any good unless you upgrade your
1006 kernel or share your Python executable with another system whose
1007 kernel has large file support.
1008
1009- The configure script now supplies plausible defaults in a
1010 cross-compilation environment. This doesn't mean that the supplied
1011 values are always correct, or that cross-compilation now works
1012 flawlessly -- but it's a first step (and it shuts up most of
1013 autoconf's warnings about AC_TRY_RUN).
1014
1015- The Unix build is now a bit less chatty, courtesy of the parser
1016 generator. The build is completely silent (except for errors) when
1017 using "make -s", thanks to a -q option to setup.py.
1018
Tim Petersb07352e2001-09-08 01:25:47 +00001019C API
1020
Guido van Rossum624c8af2001-09-18 15:21:04 +00001021- The "structmember" API now supports some new flag bits to deny read
1022 and/or write access to attributes in restricted execution mode.
1023
Tim Petersb07352e2001-09-08 01:25:47 +00001024New platforms
1025
Guido van Rossum624c8af2001-09-18 15:21:04 +00001026- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1027 (http://familiar.handhelds.org).
1028
Tim Petersb07352e2001-09-08 01:25:47 +00001029Tests
1030
Tim Peters8a9c2842001-09-22 21:30:22 +00001031- The "classic" standard tests, which work by comparing stdout to
1032 an expected-output file under Lib/test/output/, no longer stop at
1033 the first mismatch. Instead the test is run to completion, and a
1034 variant of ndiff-style comparison is used to report all differences.
1035 This is much easier to understand than the previous style of reporting.
1036
1037- The unittest-based standard tests now use regrtest's test_main()
1038 convention, instead of running as a side-effect of merely being
1039 imported. This allows these tests to be run in more natural and
1040 flexible ways as unittests, outside the regrtest framework.
1041
1042- regrtest.py is much better integrated with unittest and doctest now,
1043 especially in regard to reporting errors.
1044
Tim Petersb07352e2001-09-08 01:25:47 +00001045Windows
1046
Guido van Rossum624c8af2001-09-18 15:21:04 +00001047- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001048 that support it (NTFS under Windows 2000). See "What's New in
1049 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001050
Tim Petersb07352e2001-09-08 01:25:47 +00001051
Tim Petersedc99312001-08-22 21:36:50 +00001052What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001053Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001054===========================
1055
1056Core
1057
Tim Peters9fffa3e2001-09-04 05:14:19 +00001058- Conversion of long to float now raises OverflowError if the long is too
1059 big to represent as a C double.
1060
Tim Peters32f453e2001-09-03 08:35:41 +00001061- The 3-argument builtin pow() no longer allows a third non-None argument
1062 if either of the first two arguments is a float, or if both are of
1063 integer types and the second argument is negative (in which latter case
1064 the arguments are converted to float, so this is really the same
1065 restriction).
1066
Tim Peters5d2b77c2001-09-03 05:47:38 +00001067- The builtin dir() now returns more information, and sometimes much
1068 more, generally naming all attributes of an object, and all attributes
1069 reachable from the object via its class, and from its class's base
1070 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1071 an empty list. In 2.2a3,
1072
1073 >>> dir([])
1074 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1075 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1076 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1077 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1078 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1079 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1080 'reverse', 'sort']
1081
1082 dir(module) continues to return only the module's attributes, though.
1083
Tim Petersbdee63f2001-09-02 03:40:59 +00001084- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001085 than raising OverflowError. This is a partial implementation of PEP
1086 237. You can use -Wdefault::OverflowWarning to enable a warning for
1087 this situation, and -Werror::OverflowWarning to revert to the old
1088 OverflowError exception.
1089
Guido van Rossum61c345f2001-09-04 03:26:15 +00001090- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001091 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001092 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1093 -Qold, meaning the / operator has its classic meaning and no
1094 warnings are issued. Using -Qwarn issues a run-time warning about
1095 all uses of classic division for int and long arguments; -Qwarnall
1096 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001097 (for use with fixdiv.py).
1098 [Note: the remainder of this paragraph (preserved below) became
1099 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1100 <obsolete>
1101 Using -Qnew is questionable; it turns on new division by default, but
1102 only in the __main__ module. You can usefully combine -Qwarn or
1103 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1104 warns about classic division everywhere else.
1105 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001106
Tim Petersbdee63f2001-09-02 03:40:59 +00001107- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001108 long, float, str, unicode, and tuple. (The types complex, list and
1109 dictionary can also be subclassed; this was introduced earlier.)
1110 Note that restrictions apply when subclassing immutable built-in
1111 types: you can only affect the value of the instance by overloading
1112 __new__. You can add mutable attributes, and the subclass instances
1113 will have a __dict__ attribute, but you cannot change the "value"
1114 (as implemented by the base class) of an immutable subclass instance
1115 once it is created.
1116
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001117- The dictionary constructor now takes an optional argument, a
1118 mapping-like object, and initializes the dictionary from its
1119 (key, value) pairs.
1120
Tim Petersbdee63f2001-09-02 03:40:59 +00001121- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001122 "cooperative super calls" in a multiple inheritance setting. For an
1123 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1124
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001125- A new built-in type, property, has been added. This enables the
1126 creation of "properties". These are attributes implemented by
1127 getter and setter functions (or only one of these for read-only or
1128 write-only attributes), without the need to override __getattr__.
1129 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001130
Tim Petersbdee63f2001-09-02 03:40:59 +00001131- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001132 liberalized, to allow leading zeroes. Examples of literals now
1133 legal that were SyntaxErrors before:
1134
1135 00.0 0e3 0100j 07.5 00000000000000000008.
1136
Tim Petersbdee63f2001-09-02 03:40:59 +00001137- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001138 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1139
Tim Petersedc99312001-08-22 21:36:50 +00001140Library
1141
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001142- telnetlib includes symbolic names for the options, and support for
1143 setting an option negotiation callback.
1144
Tim Petersa40c7932001-09-05 22:36:56 +00001145- The new C standard no longer requires that math libraries set errno to
1146 ERANGE on overflow. For platform libraries that exploit this new
1147 freedom, Python's overflow-checking was wholly broken. A new overflow-
1148 checking scheme attempts to repair that, but may not be reliable on all
1149 platforms (C doesn't seem to provide anything both useful and portable
1150 in this area anymore).
1151
Martin v. Löwis44f86962001-09-05 13:44:54 +00001152- Asynchronous timeout actions are available through the new class
1153 threading.Timer.
1154
Tim Peters78526162001-09-05 00:53:45 +00001155- math.log and math.log10 now return sensible results for even huge
1156 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1157
Tim Petersbdee63f2001-09-02 03:40:59 +00001158- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001159 currently held. See the docs for the imp module.
1160
Tim Petersbdee63f2001-09-02 03:40:59 +00001161- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001162 dumps containing ints written on platforms where Python ints are 8 bytes.
1163 When read on a box where Python ints are 4 bytes, such values are
1164 converted to Python longs.
1165
Tim Petersbdee63f2001-09-02 03:40:59 +00001166- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001167 code objects is no longer allowed. This plugs a security hole.
1168
Steve Purcell6091cd62001-09-06 16:05:17 +00001169- unittest.TestResult instances no longer store references to tracebacks
1170 generated by test failures. This prevents unexpected dangling references
1171 to objects that should be garbage collected between tests.
1172
Tim Petersedc99312001-08-22 21:36:50 +00001173Tools
1174
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001175- Tools/scripts/fixdiv.py has been added which can be used to fix
1176 division operators as per PEP 238.
1177
Tim Petersedc99312001-08-22 21:36:50 +00001178Build
1179
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001180- If you are an adventurous person using Mac OS X you may want to look at
1181 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1182 application, which can be used for experimenting with Carbon or Cocoa.
1183 Discussion of this on pythonmac-sig, please.
1184
Tim Peters7eea37e2001-09-04 22:08:56 +00001185C API
1186
1187- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001188
Tim Peters9fffa3e2001-09-04 05:14:19 +00001189- Note that PyLong_AsDouble can fail! This has always been true, but no
1190 callers checked for it. It's more likely to fail now, because overflow
1191 errors are properly detected now. The proper way to check:
1192
1193 double x = PyLong_AsDouble(some_long_object);
1194 if (x == -1.0 && PyErr_Occurred()) {
1195 /* The conversion failed. */
1196 }
1197
Tim Petersbdee63f2001-09-02 03:40:59 +00001198- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001199 compile but will not participate in GC. To upgrade an extension
1200 module:
1201
1202 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001203
Neil Schemenauer4042c692001-08-30 15:38:01 +00001204 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1205 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001206
Neil Schemenauer4042c692001-08-30 15:38:01 +00001207 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1208 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001209
Neil Schemenauer4042c692001-08-30 15:38:01 +00001210 - remove PyGC_HEAD_SIZE from object size calculations
1211
1212 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1213
Tim Petersbdee63f2001-09-02 03:40:59 +00001214- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001215 These can be used safely to construct string objects from a
1216 sprintf-style format string (similar to the format string supported
1217 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001218
Tim Petersedc99312001-08-22 21:36:50 +00001219New platforms
1220
Tim Petersb7da0902001-09-02 23:01:43 +00001221- Stephen Hansen contributed patches sufficient to get a clean compile
1222 under Borland C (Windows), but he reports problems running it and ran
1223 out of time to complete the port. Volunteers? Expect a MemoryError
1224 when importing the types module; this is probably shallow, and
1225 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001226
Tim Petersedc99312001-08-22 21:36:50 +00001227Tests
1228
1229Windows
1230
Tim Peters6e13a562001-09-06 00:32:15 +00001231- Large file support is now enabled on Win32 platforms as well as on
1232 Win64. This means that, for example, you can use f.tell() and f.seek()
1233 to manipulate files larger than 2 gigabytes (provided you have enough
1234 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001235 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1236 filesize limit, and large file support makes no difference there.
1237 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1238 NTFS has no practical limit on file size, and files of any size can be
1239 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001240
Tim Petersbdee63f2001-09-02 03:40:59 +00001241- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001242 points to command.com (patch from Brian Quinlan).
1243
Tim Petersedc99312001-08-22 21:36:50 +00001244
Tim Peters20f51a72001-07-21 02:31:40 +00001245What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001246Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001247===========================
1248
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001249Build
1250
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001251- Tim Peters developed a brand new Windows installer using Wise 8.1,
1252 generously donated to us by Wise Solutions.
1253
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001254- configure supports a new option --enable-unicode, with the values
1255 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1256 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001257
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001258- A new configure option --enable-framework builds a Mac OS X framework,
1259 which "make frameworkinstall" will install. This provides a starting
1260 point for more mac-like functionality, join pythonmac-sig@python.org
1261 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001262
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001263- The NeXT platform is no longer supported.
1264
1265- The `new' module is now statically linked.
1266
Tim Peters0afb6092001-08-15 06:06:44 +00001267Tools
1268
1269- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001270 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001271 the module docstring for details.
1272
Tim Peters20f51a72001-07-21 02:31:40 +00001273Tests
1274
Tim Peters5e824c32001-08-12 22:25:01 +00001275- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001276 platforms, allowing to give clearer test result output. regrtest
1277 also has optional --use/-u switch to run normally disabled tests
1278 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001279
Tim Peters20f51a72001-07-21 02:31:40 +00001280- Several new tests in the standard test suite, with special thanks to
1281 Nick Mathewson.
1282
1283Core
1284
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001285- The floor division operator // has been added as outlined in PEP
1286 238. The / operator still provides classic division (and will until
1287 Python 3.0) unless "from __future__ import division" is included, in
1288 which case the / operator will provide true division. The operator
1289 module provides truediv() and floordiv() functions. Augmented
1290 assignment variants are included, as are the equivalent overloadable
1291 methods and C API methods. See the PEP for a full discussion:
1292 <http://python.sf.net/peps/pep-0238.html>
1293
Tim Peters6cd6a822001-08-17 22:11:27 +00001294- Future statements are now effective in simulated interactive shells
1295 (like IDLE). This should "just work" by magic, but read Michael
1296 Hudson's "Future statements in simulated shells" PEP 264 for full
1297 details: <http://python.sf.net/peps/pep-0264.html>.
1298
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001299- The type/class unification (PEP 252-253) was integrated into the
1300 trunk and is not so tentative any more (the exact specification of
1301 some features is still tentative). A lot of work has done on fixing
1302 bugs and adding robustness and features (performance still has to
1303 come a long way).
1304
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001305- Warnings about a mismatch in the Python API during extension import
1306 now use the Python warning framework (which makes it possible to
1307 write filters for these warnings).
1308
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001309- A function's __dict__ (aka func_dict) will now always be a
1310 dictionary. It used to be possible to delete it or set it to None,
1311 but now both actions raise TypeErrors. It is still legal to set it
1312 to a dictionary object. Getting func.__dict__ before any attributes
1313 have been assigned now returns an empty dictionary instead of None.
1314
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001315- A new command line option, -E, was added which disables the use of
1316 all environment variables, or at least those that are specifically
1317 significant to Python. Usually those have a name starting with
1318 "PYTHON". This was used to fix a problem where the tests fail if
1319 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1320 older distribution.
1321
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001322Library
1323
Tim Peters5e824c32001-08-12 22:25:01 +00001324- New class Differ and new functions ndiff() and restore() in difflib.py.
1325 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001326 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001327
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001328- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1329 value using the minimal quoting required for the value; more
1330 reliable than using xml.sax.saxutils.escape() for attribute values.
1331
1332- Readline completion support for cmd.Cmd was added.
1333
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001334- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1335
1336- Added function threading.BoundedSemaphore()
1337
1338- Added Ka-Ping Yee's cgitb.py module.
1339
1340- The `new' module now exposes the CO_xxx flags.
1341
Martin v. Löwis560da622001-11-24 09:24:51 +00001342- The gc module offers the get_referents function.
1343
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001344New platforms
1345
1346C API
1347
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001348- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1349 which provide a cross-platform implementations for the
1350 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1351 the standard sprintf() and vsprintf() C lib APIs, these versions
1352 apply bounds checking on the used buffer which enhances protection
1353 against buffer overruns.
1354
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001355- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001356 and extensions using different Unicode widths is rendered next to
1357 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001358 will result in an ImportError. Unicode extensions writers must make
1359 sure to check the Unicode width compatibility in their extensions by
1360 using at least one of the mangled Unicode APIs in the extension.
1361
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001362- Two new flags METH_NOARGS and METH_O are available in method definition
1363 tables to simplify implementation of methods with no arguments and a
1364 single untyped argument. Calling such methods is more efficient than
1365 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1366 deprecated.
1367
Tim Petersc1731372001-08-04 08:12:36 +00001368Windows
1369
1370- "import module" now compiles module.pyw if it exists and nothing else
1371 relevant is found.
1372
Tim Peters20f51a72001-07-21 02:31:40 +00001373
Guido van Rossum55a78992001-07-17 17:22:32 +00001374What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001375Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001376===========================
1377
1378Core
Tim Petersa814db52001-05-14 07:05:58 +00001379
Tim Peters6d6c1a32001-08-02 04:15:00 +00001380- TENTATIVELY, a large amount of code implementing much of what's
1381 described in PEP 252 (Making Types Look More Like Classes) and PEP
1382 253 (Subtyping Built-in Types) was added. This will be released
1383 with Python 2.2a1. Documentation will be provided separately
1384 through http://www.python.org/2.2/. The purpose of releasing this
1385 with Python 2.2a1 is to test backwards compatibility. It is
1386 possible, though not likely, that a decision is made not to release
1387 this code as part of 2.2 final, if any serious backwards
1388 incompapatibilities are found during alpha testing that cannot be
1389 repaired.
1390
Guido van Rossum55a78992001-07-17 17:22:32 +00001391- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001392 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001393 more 'yield' statements. See PEP 255. Since this adds a new
1394 keyword to the language, this feature must be enabled by including a
1395 future statement: "from __future__ import generators" (see PEP 236).
1396 Generators will become a standard feature in a future release
1397 (probably 2.3). Without this future statement, 'yield' remains an
1398 ordinary identifier, but a warning is issued each time it is used.
1399 (These warnings currently don't conform to the warnings framework of
1400 PEP 230; we intend to fix this in 2.2a2.)
1401
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001402- The UTF-16 codec was modified to be more RFC compliant. It will now
1403 only remove BOM characters at the start of the string and then
1404 only if running in native mode (UTF-16-LE and -BE won't remove a
1405 leading BMO character).
1406
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001407- Strings now have a new method .decode() to complement the already
1408 existing .encode() method. These two methods provide direct access
1409 to the corresponding decoders and encoders of the registered codecs.
1410
1411 To enhance the usability of the .encode() method, the special
1412 casing of Unicode object return values was dropped (Unicode objects
1413 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001414
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001415 Both methods will now return whatever the codec in charge of the
1416 requested encoding returns as object, e.g. Unicode codecs will
1417 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1418 will return u"äöü"). This enables codec writer to create codecs
1419 for various simple to use conversions.
1420
1421 New codecs were added to demonstrate these new features (the .encode()
1422 and .decode() columns indicate the type of the returned objects):
1423
1424 Name | .encode() | .decode() | Description
1425 ----------------------------------------------------------------------
1426 uu | string | string | UU codec (e.g. for email)
1427 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001428 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001429 zlib | string | string | zlib compression
1430 hex | string | string | 2-byte hex codec
1431 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1432
Mark Hammond2a0af792001-05-14 03:09:36 +00001433- Some operating systems now support the concept of a default Unicode
1434 encoding for file system operations. Notably, Windows supports 'mbcs'
1435 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001436 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001437 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001438
1439 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001440 functions that return filenames (such as os.listdir()) to return Python
1441 string objects pre-encoded using the default file system encoding for
1442 the platform. As this encoding is likely to be different from Python's
1443 default encoding, converting this name to a Unicode object before passing
1444 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001445 would attempt to use its default encoding (generally ASCII) rather than
1446 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001447
Tim Petersa814db52001-05-14 07:05:58 +00001448 In general, this change simply removes surprises when working with
1449 Unicode and the file system, making these operations work as you expect,
1450 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001451 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001452
Tim Peters61dff2b2001-05-08 15:43:37 +00001453- Float (and complex) literals in source code were evaluated to full
1454 precision only when running from a .py file; the same code loaded from a
1455 .pyc (or .pyo) file could suffer numeric differences starting at about the
1456 12th significant decimal digit. For example, on a machine with IEEE-754
1457 floating arithmetic,
1458
1459 x = 9007199254740992.0
1460 print long(x)
1461
1462 printed 9007199254740992 if run directly from .py, but 9007199254740000
1463 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1464 str(float) instead of repr(float) when building code objects. marshal
1465 now uses repr(float) instead, which should reproduce floats to full
1466 machine precision (assuming the platform C float<->string I/O conversion
1467 functions are of good quality).
1468
1469 This may cause floating-point results to change in some cases, and
1470 usually for the better, but may also cause numerically unstable
1471 algorithms to break.
1472
Tim Peters2f228e72001-05-13 00:19:31 +00001473- The implementation of dicts suffers fewer collisions, which has speed
1474 benefits. However, the order in which dict entries appear in dict.keys(),
1475 dict.values() and dict.items() may differ from previous releases for a
1476 given dict. Nothing is defined about this order, so no program should
1477 rely on it. Nevertheless, it's easy to write test cases that rely on the
1478 order by accident, typically because of printing the str() or repr() of a
1479 dict to an "expected results" file. See Lib/test/test_support.py's new
1480 sortdict(dict) function for a simple way to display a dict in sorted
1481 order.
1482
Tim Peters7a3bfc32001-06-12 01:22:22 +00001483- Many other small changes to dicts were made, resulting in faster
1484 operation along the most common code paths.
1485
Guido van Rossum10315822001-05-01 20:54:30 +00001486- Dictionary objects now support the "in" operator: "x in dict" means
1487 the same as dict.has_key(x).
1488
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001489- The update() method of dictionaries now accepts generic mapping
1490 objects. Specifically the argument object must support the .keys()
1491 and __getitem__() methods. This allows you to say, for example,
1492 {}.update(UserDict())
1493
Guido van Rossum10315822001-05-01 20:54:30 +00001494- Iterators were added; this is a generalized way of providing values
1495 to a for loop. See PEP 234. There's a new built-in function iter()
1496 to return an iterator. There's a new protocol to get the next value
1497 from an iterator using the next() method (in Python) or the
1498 tp_iternext slot (in C). There's a new protocol to get iterators
1499 using the __iter__() method (in Python) or the tp_iter slot (in C).
1500 Iterating (i.e. a for loop) over a dictionary generates its keys.
1501 Iterating over a file generates its lines.
1502
Tim Petersf553f892001-05-01 20:45:31 +00001503- The following functions were generalized to work nicely with iterator
1504 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001505 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001506 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1507 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001508 join() method of strings
1509 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001510 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1511 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001512 right-hand side of assignment statements with multiple targets, such as
1513 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001514
Tim Petersd85e1022001-05-11 21:51:48 +00001515- Accessing module attributes is significantly faster (for example,
1516 random.random or os.path or yourPythonModule.yourAttribute).
1517
Tim Peterse63415e2001-05-08 04:38:29 +00001518- Comparing dictionary objects via == and != is faster, and now works even
1519 if the keys and values don't support comparisons other than ==.
1520
Tim Peters95bf9392001-05-10 08:32:44 +00001521- Comparing dictionaries in ways other than == and != is slower: there were
1522 insecurities in the dict comparison implementation that could cause Python
1523 to crash if the element comparison routines for the dict keys and/or
1524 values mutated the dicts. Making the code bulletproof slowed it down.
1525
Tim Peterseb28ef22001-06-02 05:27:19 +00001526- Collisions in dicts are resolved via a new approach, which can help
1527 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001528 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001529 faster now. Thanks to Christian Tismer for pointing out the cause and
1530 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001531
Tim Peters52e155e2001-06-16 05:42:57 +00001532- repr() is much faster for large containers (dict, list, tuple).
1533
1534
Tim Petersa814db52001-05-14 07:05:58 +00001535Library
1536
Fred Drake960fdf92001-07-20 18:38:26 +00001537- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1538 were added to the string module. These a locale-indenpendent
1539 constants, unlike letters, lowercase, and uppercase. These are now
1540 use in appropriate locations in the standard library.
1541
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001542- The flags used in dlopen calls can now be configured using
1543 sys.setdlopenflags and queried using sys.getdlopenflags.
1544
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001545- Fredrik Lundh's xmlrpclib is now a standard library module. This
1546 provides full client-side XML-RPC support. In addition,
1547 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1548 one asyncore-based). Thanks to Eric Raymond for the documentation.
1549
Guido van Rossum643d3912001-07-05 14:46:25 +00001550- The xrange() object is simplified: it no longer supports slicing,
1551 repetition, comparisons, efficient 'in' checking, the tolist()
1552 method, or the start, stop and step attributes. See PEP 260.
1553
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001554- A new function fnmatch.filter to filter lists of file names was added.
1555
Barry Warsawffd674d2001-05-22 16:00:10 +00001556- calendar.py uses month and day names based on the current locale.
1557
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001558- strop is now *really* obsolete (this was announced before with 1.6),
1559 and issues DeprecationWarning when used (except for the four items
1560 that are still imported into string.py).
1561
Tim Petersa814db52001-05-14 07:05:58 +00001562- Cookie.py now sorts key+value pairs by key in output strings.
1563
1564- pprint.isrecursive(object) didn't correctly identify recursive objects.
1565 Now it does.
1566
Tim Peters95b3f782001-05-14 18:39:41 +00001567- pprint functions now much faster for large containers (tuple, list, dict).
1568
Tim Peters7b9542a2001-06-10 23:40:19 +00001569- New 'q' and 'Q' format codes in the struct module, corresponding to C
1570 types "long long" and "unsigned long long" (on Windows, __int64). In
1571 native mode, these can be used only when the platform C compiler supports
1572 these types (when HAVE_LONG_LONG is #define'd by the Python config
1573 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001574 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1575 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001576
Guido van Rossum83213cc2001-06-12 16:48:52 +00001577- The site module installs a new built-in function 'help' that invokes
1578 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1579 it displays a message reminding the user to use 'help()' or
1580 'help(object)'.
1581
Tim Petersa814db52001-05-14 07:05:58 +00001582Tests
1583
1584- New test_mutants.py runs dict comparisons where the key and value
1585 comparison operators mutute the dicts randomly during comparison. This
1586 rapidly causes Python to crash under earlier releases (not for the faint
1587 of heart: it can also cause Win9x to freeze or reboot!).
1588
1589- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001590 pprint.isreadable() return sensible results. Also verifies that simple
1591 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001592
Tim Peters4324aa32001-05-28 22:30:08 +00001593C API
1594
1595- Removed the unused last_is_sticky argument from the internal
1596 _PyTuple_Resize(). If this affects you, you were cheating.
1597
1598
Guido van Rossum55a78992001-07-17 17:22:32 +00001599======================================================================
1600
1601
Guido van Rossumffe13be2001-04-16 18:46:45 +00001602What's New in Python 2.1 (final)?
1603=================================
1604
1605We only changed a few things since the last release candidate, all in
1606Python library code:
1607
1608- A bug in the locale module was fixed that affected locales which
1609 define no grouping for numeric formatting.
1610
1611- A few bugs in the weakref module's implementations of weak
1612 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1613 and the test suite was updated to check for these bugs.
1614
1615- An old bug in the os.path.walk() function (introduced in Python
1616 2.0!) was fixed: a non-existent file would cause an exception
1617 instead of being ignored.
1618
1619- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1620 PyChecker.
1621
1622
Guido van Rossum5b08f132001-04-16 02:05:23 +00001623What's New in Python 2.1c2?
1624===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001625
Guido van Rossum5b08f132001-04-16 02:05:23 +00001626A flurry of small changes, and one showstopper fixed in the nick of
1627time made it necessary to release another release candidate. The list
1628here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001629
Guido van Rossum5b08f132001-04-16 02:05:23 +00001630Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001631
Guido van Rossum5b08f132001-04-16 02:05:23 +00001632- Tim discovered a nasty bug in the dictionary code, caused by
1633 PyDict_Next() calling dict_resize(), and the GC code's use of
1634 PyDict_Next() violating an assumption in dict_items(). This was
1635 fixed with considerable amounts of band-aid, but the net effect is a
1636 saner and more robust implementation.
1637
1638- Made a bunch of symbols static that were accidentally global.
1639
1640Build and Ports
1641
1642- The setup.py script didn't check for a new enough version of zlib
1643 (1.1.3 is needed). Now it does.
1644
1645- Changed "make clean" target to also remove shared libraries.
1646
1647- Added a more general warning about the SGI Irix optimizer to README.
1648
1649Library
1650
1651- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1652 omitted the slash between host and file.html.
1653
1654- The mailbox module's _Mailbox class contained a completely broken
1655 and undocumented seek() method. Ripped it out.
1656
1657- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1658 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1659
1660- Fixed a few last-minute bugs in unittest.
1661
1662Extensions
1663
1664- Reverted the patch to the OpenSSL code in socketmodule.c to support
1665 RAND_status() and the EGD, and the subsequent patch that tried to
1666 fix it for pre-0.9.5 versions; the problem with the patch is that on
1667 some systems it issues a warning whenever socket is imported, and
1668 that's unacceptable.
1669
1670Tests
1671
1672- Fixed the pickle tests to work with "import test.test_pickle".
1673
1674- Tweaked test_locale.py to actually run the test Windows.
1675
1676- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1677 not "wb" (which is not a valid mode at all).
1678
1679- Fix pstats browser crashes. Import readline if it exists to make
1680 the user interface nicer.
1681
1682- Add "import thread" to the top of test modules that import the
1683 threading module (test_asynchat and test_threadedtempfile). This
1684 prevents test failures caused by a broken threading module resulting
1685 from a previously caught failed import.
1686
1687- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1688 needed on some platforms (e.g. Solaris 8) when the tests are run
1689 twice in succession.
1690
1691- Skip rather than fail test_sunaudiodev if no audio device is found.
1692
1693
1694What's New in Python 2.1c1?
1695===========================
1696
1697This list was significantly updated when 2.1c2 was released; the 2.1c1
1698release didn't mention most changes that were actually part of 2.1c1:
1699
1700Legal
1701
1702- Copyright was assigned to the Python Software Foundation (PSF) and a
1703 PSF license (very similar to the CNRI license) was added.
1704
1705- The CNRI copyright notice was updated to include 2001.
1706
1707Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001708
Guido van Rossumc9932722001-04-12 02:31:27 +00001709- After a public outcry, assignment to __debug__ is no longer illegal;
1710 instead, a warning is issued. It will become illegal in 2.2.
1711
Guido van Rossum5b08f132001-04-16 02:05:23 +00001712- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1713 "%#x" now always prepends "0x", even if the value is zero.
1714
1715- Fixed some nits in the bytecode compiler.
1716
1717- Fixed core dumps when calling certain kinds of non-functions.
1718
1719- Fixed various core dumps caused by reference count bugs.
1720
1721Build and Ports
1722
1723- Use INSTALL_SCRIPT to install script files.
1724
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001725- New port: SCO Unixware 7, by Billy G. Allie.
1726
Guido van Rossum5b08f132001-04-16 02:05:23 +00001727- Updated RISCOS port.
1728
1729- Updated BeOS port and notes.
1730
1731- Various other porting problems resolved.
1732
1733Library
1734
1735- The TERMIOS and SOCKET modules are now truly obsolete and
1736 unnecessary. Their symbols are incorporated in the termios and
1737 socket modules.
1738
1739- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1740 better tests for pickling.
1741
1742- threading: make Condition.wait() robust against KeyboardInterrupt.
1743
1744- zipfile: add support to zipfile to support opening an archive
1745 represented by an open file rather than a file name. Fix bug where
1746 the archive was not properly closed. Fixed a bug in this bugfix
1747 where flush() was called for a read-only file.
1748
1749- imputil: added an uninstall() method to the ImportManager.
1750
1751- Canvas: fixed bugs in lower() and tkraise() methods.
1752
1753- SocketServer: API change (added overridable close_request() method)
1754 so that the TCP server can explicitly close the request.
1755
1756- pstats: Eric Raymond added a simple interactive statistics browser,
1757 invoked when the module is run as a script.
1758
1759- locale: fixed a problem in format().
1760
1761- webbrowser: made it work when the BROWSER environment variable has a
1762 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1763 KDE 2. Fixed some other nits.
1764
1765- unittest: changes to allow using a different exception than
1766 AssertionError, and added a few more function aliases. Some other
1767 small changes.
1768
1769- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1770
1771- asynchat: fixed a critical bug in asynchat that slipped through the
1772 2.1b2 release. Fixed another rare bug.
1773
1774- Fix some unqualified except: clauses (always a bad code example).
1775
1776XML
1777
1778- pyexpat: new API get_version_string().
1779
1780- Fixed some minidom bugs.
1781
1782Extensions
1783
1784- Fixed a core dump in _weakref. Removed the weakref.mapping()
1785 function (it adds nothing to the API).
1786
1787- Rationalized the use of header files in the readline module, to make
1788 it compile (albeit with some warnings) with the very recent readline
1789 4.2, without breaking for earlier versions.
1790
1791- Hopefully fixed a buffering problem in linuxaudiodev.
1792
1793- Attempted a fix to make the OpenSSL support in the socket module
1794 work again with pre-0.9.5 versions of OpenSSL.
1795
1796Tests
1797
1798- Added a test case for asynchat and asyncore.
1799
1800- Removed coupling between tests where one test failing could break
1801 another.
1802
1803Tools
1804
1805- Ping added an interactive help browser to pydoc, fixed some nits
1806 in the rest of the pydoc code, and added some features to his
1807 inspect module.
1808
1809- An updated python-mode.el version 4.1 which integrates Ken
1810 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1811 much nicer in XEmacs and Emacs. When stepping through your program
1812 with pdb, in either the shell window or the *Python* window, the
1813 source file and line will be tracked by an arrow. Very cool!
1814
1815- IDLE: syntax warnings in interactive mode are changed into errors.
1816
1817- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001818 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001819
1820- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001821
Barry Warsaw11e89c72001-04-11 20:37:57 +00001822
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001823What's New in Python 2.1 beta 2?
1824================================
1825
Guido van Rossum053ae352001-03-22 14:17:21 +00001826(Unlisted are many fixed bugs, more documentation, etc.)
1827
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001828Core language, builtins, and interpreter
1829
Guido van Rossum053ae352001-03-22 14:17:21 +00001830- The nested scopes work (enabled by "from __future__ import
1831 nested_scopes") is completed; in particular, the future now extends
1832 into code executed through exec, eval() and execfile(), and into the
1833 interactive interpreter.
1834
1835- When calling a base class method (e.g. BaseClass.__init__(self)),
1836 this is now allowed even if self is not strictly spoken a class
1837 instance (e.g. when using metaclasses or the Don Beaudry hook).
1838
1839- Slice objects are now comparable but not hashable; this prevents
1840 dict[:] from being accepted but meaningless.
1841
1842- Complex division is now calculated using less braindead algorithms.
1843 This doesn't change semantics except it's more likely to give useful
1844 results in extreme cases. Complex repr() now uses full precision
1845 like float repr().
1846
1847- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1848
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001849- It is illegal to assign to the name __debug__, which is set when the
1850 interpreter starts. It is effectively a compile-time constant.
1851
1852- A warning will be issued if a global statement for a variable
1853 follows a use or assignment of that variable.
1854
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001855Standard library
1856
Guido van Rossum053ae352001-03-22 14:17:21 +00001857- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1858 inspired by JUnit), is now part of the standard library. You now
1859 have a choice of two testing frameworks: unittest requires you to
1860 write testcases as separate code, doctest gathers them from
1861 docstrings. Both approaches have their advantages and
1862 disadvantages.
1863
1864- A new module Tix was added, which wraps the Tix extension library
1865 for Tk. With that module, it is not necessary to statically link
1866 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1867 require" command. See Demo/tix/.
1868
1869- tzparse.py is now obsolete.
1870
1871- In gzip.py, the seek() and tell() methods are removed -- they were
1872 non-functional anyway, and it's better if callers can test for their
1873 existence with hasattr().
1874
1875Python/C API
1876
1877- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1878 that's already in the dictionary during a PyDict_Next() iteration.
1879 This used to fail occasionally when a dictionary resize operation
1880 could be triggered that would rehash all the keys. All other
1881 modifications to the dictionary are still off-limits during a
1882 PyDict_Next() iteration!
1883
1884- New extended APIs related to passing compiler variables around.
1885
1886- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1887 implement isinstance() and issubclass().
1888
1889- Py_BuildValue() now has a "D" conversion to create a Python complex
1890 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001891
Fred Drake4e262a92001-03-22 18:26:47 +00001892- Extensions types which support weak references must now set the
1893 field allocated for the weak reference machinery to NULL themselves;
1894 this is done to avoid the cost of checking each object for having a
1895 weakly referencable type in PyObject_INIT(), since most types are
1896 not weakly referencable.
1897
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001898- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1899 free variables and cell variables to and from the frame's f_locals.
1900
1901- Variants of several functions defined in pythonrun.h have been added
1902 to support the nested_scopes future statement. The variants all end
1903 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1904 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1905 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001906 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001907
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001908Distutils
1909
1910- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1911 into the release tree.
1912
Tim Peters0e57abf2001-05-02 07:39:38 +00001913- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001914 (an uninstaller, more customization of the installer's display)
1915
1916- from Jack Jansen: added Mac-specific code to generate a dialog for
1917 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001918 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001919 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001920
1921- added 'platforms' and 'keywords' to the set of metadata that can be
1922 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001923
1924- applied patches from Jason Tishler to make the compiler class work with
1925 Cygwin.
1926
1927
Tim Peters2fe289a2001-03-01 22:19:38 +00001928What's New in Python 2.1 beta 1?
1929================================
Tim Petersd66595f2001-02-04 03:09:53 +00001930
1931Core language, builtins, and interpreter
1932
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001933- Following an outcry from the community about the amount of code
1934 broken by the nested scopes feature introduced in 2.1a2, we decided
1935 to make this feature optional, and to wait until Python 2.2 (or at
1936 least 6 months) to make it standard. The option can be enabled on a
1937 per-module basis by adding "from __future__ import nested_scopes" at
1938 the beginning of a module (before any other statements, but after
1939 comments and an optional docstring). See PEP 236 (Back to the
1940 __future__) for a description of the __future__ statement. PEP 227
1941 (Statically Nested Scopes) has been updated to reflect this change,
1942 and to clarify the semantics in a number of endcases.
1943
1944- The nested scopes code, when enabled, has been hardened, and most
1945 bugs and memory leaks in it have been fixed.
1946
1947- Compile-time warnings are now generated for a number of conditions
1948 that will break or change in meaning when nested scopes are enabled:
1949
1950 - Using "from...import *" or "exec" without in-clause in a function
1951 scope that also defines a lambda or nested function with one or
1952 more free (non-local) variables. The presence of the import* or
1953 bare exec makes it impossible for the compiler to determine the
1954 exact set of local variables in the outer scope, which makes it
1955 impossible to determine the bindings for free variables in the
1956 inner scope. To avoid the warning about import *, change it into
1957 an import of explicitly name object, or move the import* statement
1958 to the global scope; to avoid the warning about bare exec, use
1959 exec...in... (a good idea anyway -- there's a possibility that
1960 bare exec will be deprecated in the future).
1961
1962 - Use of a global variable in a nested scope with the same name as a
1963 local variable in a surrounding scope. This will change in
1964 meaning with nested scopes: the name in the inner scope will
1965 reference the variable in the outer scope rather than the global
1966 of the same name. To avoid the warning, either rename the outer
1967 variable, or use a global statement in the inner function.
1968
Neil Schemenauera35c6882001-02-27 04:45:05 +00001969- An optional object allocator has been included. This allocator is
1970 optimized for Python objects and should be faster and use less memory
1971 than the standard system allocator. It is not enabled by default
1972 because of possible thread safety problems. The allocator is only
1973 protected by the Python interpreter lock and it is possible that some
1974 extension modules require a thread safe allocator. The object
1975 allocator can be enabled by providing the "--with-pymalloc" option to
1976 configure.
1977
Tim Petersd66595f2001-02-04 03:09:53 +00001978Standard library
1979
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001980- pyexpat now detects the expat version if expat.h defines it. A
1981 number of additional handlers are provided, which are only available
1982 since expat 1.95. In addition, the methods SetParamEntityParsing and
1983 GetInputContext of Parser objects are available with 1.95.x
1984 only. Parser objects now provide the ordered_attributes and
1985 specified_attributes attributes. A new module expat.model was added,
1986 which offers a number of additional constants if 1.95.x is used.
1987
1988- xml.dom offers the new functions registerDOMImplementation and
1989 getDOMImplementation.
1990
1991- xml.dom.minidom offers a toprettyxml method. A number of DOM
1992 conformance issues have been resolved. In particular, Element now
1993 has an hasAttributes method, and the handling of namespaces was
1994 improved.
1995
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001996- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1997 getting information about live Python code, and pydoc.py, a module
1998 for interactively converting docstrings to HTML or text.
1999 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002000 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002001 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2002 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002003
Tim Peters1eff7962001-03-01 02:31:33 +00002004- New library module difflib.py, primarily packaging the SequenceMatcher
2005 class at the heart of the popular ndiff.py file-comparison tool.
2006
2007- doctest.py (a framework for verifying Python code examples in docstrings)
2008 is now part of the std library.
2009
Tim Petersd66595f2001-02-04 03:09:53 +00002010Windows changes
2011
Guido van Rossume3955a82001-03-02 14:05:59 +00002012- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2013 small GUI that lets you browse the module docstrings using your
2014 default web browser.
2015
Tim Peters1eff7962001-03-01 02:31:33 +00002016- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2017 Platforms) is implemented. See
2018
2019 http://python.sourceforge.net/peps/pep-0235.html
2020
2021 for full details, especially the "Current Lower-Left Semantics" section.
2022 The new Windows import rules are simpler than before:
2023
2024 A. If the PYTHONCASEOK environment variable exists, same as
2025 before: silently accept the first case-insensitive match of any
2026 kind; raise ImportError if none found.
2027
2028 B. Else search sys.path for the first case-sensitive match; raise
2029 ImportError if none found.
2030
2031 The same rules have been implented on other platforms with case-
2032 insensitive but case-preserving filesystems too (including Cygwin, and
2033 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002034
Tim Peters25a9ce32001-02-19 07:06:36 +00002035- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2036 what it's supposed to do (and does do under NT and 2000) via direct
2037 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002038 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002039 all Win9x systems before.
2040
Tim Peters1eff7962001-03-01 02:31:33 +00002041- Build: Subproject _test (effectively) renamed to _testcapi.
2042
Tim Peters2fe289a2001-03-01 22:19:38 +00002043New platforms
2044
2045- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2046 Thanks to Steven Majewski!
2047
2048- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2049 Tishler!
2050
Guido van Rossum9089b272001-03-02 06:49:50 +00002051- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2052 Schwertberger! See RISCOS/README for more information -- it seems
2053 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002054 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002055
Tim Peters25a9ce32001-02-19 07:06:36 +00002056
Tim Petersd7b5e882001-01-25 03:36:26 +00002057What's New in Python 2.1 alpha 2?
2058=================================
Tim Peters40ead762001-01-27 05:35:26 +00002059
Tim Petersd7b5e882001-01-25 03:36:26 +00002060Core language, builtins, and interpreter
2061
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002062- Scopes nest. If a name is used in a function or class, but is not
2063 local, the definition in the nearest enclosing function scope will
2064 be used. One consequence of this change is that lambda statements
2065 could reference variables in the namespaces where the lambda is
2066 defined. In some unusual cases, this change will break code.
2067
2068 In all previous version of Python, names were resolved in exactly
2069 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002070 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002071 function A is defined within a function B, the names bound in B are
2072 not visible in A. The new rules make names bound in B visible in A,
2073 unless A contains a name binding that hides the binding in B.
2074
2075 Section 4.1 of the reference manual describes the new scoping rules
2076 in detail. The test script in Lib/test/test_scope.py demonstrates
2077 some of the effects of the change.
2078
2079 The new rules will cause existing code to break if it defines nested
2080 functions where an outer function has local variables with the same
2081 name as globals or builtins used by the inner function. Example:
2082
2083 def munge(str):
2084 def helper(x):
2085 return str(x)
2086 if type(str) != type(''):
2087 str = helper(str)
2088 return str.strip()
2089
2090 Under the old rules, the name str in helper() is bound to the
2091 builtin function str(). Under the new rules, it will be bound to
2092 the argument named str and an error will occur when helper() is
2093 called.
2094
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002095- The compiler will report a SyntaxError if "from ... import *" occurs
2096 in a function or class scope. The language reference has documented
2097 that this case is illegal, but the compiler never checked for it.
2098 The recent introduction of nested scope makes the meaning of this
2099 form of name binding ambiguous. In a future release, the compiler
2100 may allow this form when there is no possibility of ambiguity.
2101
Tim Peters40ead762001-01-27 05:35:26 +00002102- repr(string) is easier to read, now using hex escapes instead of octal,
2103 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2104
2105 >>> "\texample \r\n" + chr(0) + chr(255)
2106 '\texample \r\n\x00\xff' # in 2.1
2107 '\011example \015\012\000\377' # in 2.0
2108
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002109- Functions are now compared and hashed by identity, not by value, since
2110 the func_code attribute is writable.
2111
Fred Drakefb9d7122001-02-01 20:00:40 +00002112- Weak references (PEP 205) have been added. This involves a few
2113 changes in the core, an extension module (_weakref), and a Python
2114 module (weakref). The weakref module is the public interface. It
2115 includes support for "explicit" weak references, proxy objects, and
2116 mappings with weakly held values.
2117
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002118- A 'continue' statement can now appear in a try block within the body
2119 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002120 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002121
Tim Petersd7b5e882001-01-25 03:36:26 +00002122Standard library
2123
Barry Warsaw30dbd142001-01-31 22:14:01 +00002124- mailbox.py now has a new class, PortableUnixMailbox which is
2125 identical to UnixMailbox but uses a more portable scheme for
2126 determining From_ separators. Also, the constructors for all the
2127 classes in this module have a new optional `factory' argument, which
2128 is a callable used when new message classes must be instantiated by
2129 the next() method.
2130
Tim Petersd7b5e882001-01-25 03:36:26 +00002131- random.py is now self-contained, and offers all the functionality of
2132 the now-deprecated whrandom.py. See the docs for details. random.py
2133 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002134 and restoring the internal state of the generator; and jumpahead(n),
2135 for quickly forcing the internal state to be the same as if n calls to
2136 random() had been made. The latter is particularly useful for multi-
2137 threaded programs, creating one instance of the random.Random() class for
2138 each thread, then using .jumpahead() to force each instance to use a
2139 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002140
Tim Peters0de88fc2001-02-01 04:59:18 +00002141- random.py's seed() function is new. For bit-for-bit compatibility with
2142 prior releases, use the whseed function instead. The new seed function
2143 addresses two problems: (1) The old function couldn't produce more than
2144 about 2**24 distinct internal states; the new one about 2**45 (the best
2145 that can be done in the Wichmann-Hill generator). (2) The old function
2146 sometimes produced identical internal states when passed distinct
2147 integers, and there was no simple way to predict when that would happen;
2148 the new one guarantees to produce distinct internal states for all
2149 arguments in [0, 27814431486576L).
2150
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002151- The socket module now supports raw packets on Linux. The socket
2152 family is AF_PACKET.
2153
Tim Peters9ea17ac2001-02-02 05:57:15 +00002154- test_capi.py is a start at running tests of the Python C API. The tests
2155 are implemented by the new Modules/_testmodule.c.
2156
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002157- A new extension module, _symtable, provides provisional access to the
2158 internal symbol table used by the Python compiler. A higher-level
2159 interface will be added on top of _symtable in a future release.
2160
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002161- Removed the obsolete soundex module.
2162
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002163- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2164 the isSameNode method; NamedNodeMap the get method.
2165
2166- xml.sax.expatreader supports the lexical handler property; it
2167 generates comment, startCDATA, and endCDATA events.
2168
Tim Petersee826f82001-01-31 19:39:44 +00002169Windows changes
2170
2171- Build procedure: the zlib project is built in a different way that
2172 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002173 the zlib binary used. See PCbuild\readme.txt for details. Your old
2174 zlib-related directories can be deleted; you'll need to download fresh
2175 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002176
Tim Peters9ea17ac2001-02-02 05:57:15 +00002177- Build: New subproject _test for the benefit of test_capi.py (see above).
2178
Tim Petersb16c56f2001-02-02 21:24:51 +00002179- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2180 interface to some Python compiler internals).
2181
2182- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002183 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002184
Tim Petersa3a3a032000-11-30 05:22:44 +00002185What's New in Python 2.1 alpha 1?
2186=================================
2187
2188Core language, builtins, and interpreter
2189
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002190- There is a new Unicode companion to the PyObject_Str() API
2191 called PyObject_Unicode(). It behaves in the same way as the
2192 former, but assures that the returned value is an Unicode object
2193 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002194
Guido van Rossumf98eda02001-01-17 15:54:45 +00002195- The comparison operators support "rich comparison overloading" (PEP
2196 207). C extension types can provide a rich comparison function in
2197 the new tp_richcompare slot in the type object. The cmp() function
2198 and the C function PyObject_Compare() first try the new rich
2199 comparison operators before trying the old 3-way comparison. There
2200 is also a new C API PyObject_RichCompare() (which also falls back on
2201 the old 3-way comparison, but does not constrain the outcome of the
2202 rich comparison to a Boolean result).
2203
2204 The rich comparison function takes two objects (at least one of
2205 which is guaranteed to have the type that provided the function) and
2206 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2207 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2208 object, which may be NotImplemented (in which case the tp_compare
2209 slot function is used as a fallback, if defined).
2210
2211 Classes can overload individual comparison operators by defining one
2212 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002213 __ge__. There are no explicit "reflected argument" versions of
2214 these; instead, __lt__ and __gt__ are each other's reflection,
2215 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2216 reflection (similar at the C level). No other implications are
2217 made; in particular, Python does not assume that == is the Boolean
2218 inverse of !=, or that < is the Boolean inverse of >=. This makes
2219 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002220
2221 Classes or types that want to implement (in)equality tests but not
2222 the ordering operators (i.e. unordered types) should implement ==
2223 and !=, and raise an error for the ordering operators.
2224
Guido van Rossuma88479f2001-01-18 14:28:08 +00002225 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002226 Boolean; e.g. a matrix type might want to return a matrix of bits
2227 for A < B, giving elementwise comparisons. Such types should ensure
2228 that any interpretation of their value in a Boolean context raises
2229 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2230 at the C level) to always raise an exception.
2231
Guido van Rossuma88479f2001-01-18 14:28:08 +00002232- Complex numbers use rich comparisons to define == and != but raise
2233 an exception for <, <=, > and >=. Unfortunately, this also means
2234 that cmp() of two complex numbers raises an exception when the two
2235 numbers differ. Since it is not mathematically meaningful to compare
2236 complex numbers except for equality, I hope that this doesn't break
2237 too much code.
2238
Tim Peters3389f192001-02-18 08:48:49 +00002239- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002240 not defined by the language, other than that it's arbitrary but
2241 consistent (see the Reference Manual). An implementation detail changed
2242 in 2.1a1 such that None now compares less than any other object. Code
2243 relying on this new behavior (like code that relied on the previous
2244 behavior) does so at its own risk.
2245
Barry Warsaw573b5412001-01-15 20:43:18 +00002246- Functions and methods now support getting and setting arbitrarily
2247 named attributes (PEP 232). Functions have a new __dict__
2248 (a.k.a. func_dict) which hold the function attributes. Methods get
2249 and set attributes on their underlying im_func. It is a TypeError
2250 to set an attribute on a bound method.
2251
Guido van Rossum051e3352001-01-15 19:11:10 +00002252- The xrange() object implementation has been improved so that
2253 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2254 limitation that in this case len(xrange(sys.maxint)) can't be
2255 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2256 work fine as long as the index i doesn't actually reach 2**31.
2257 (Python uses regular ints for sequence and string indices; fixing
2258 that is much more work.)
2259
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002260- Two changes to from...import:
2261
Guido van Rossumba381232001-02-03 15:06:40 +00002262 1) "from M import X" now works even if (after loading module M)
2263 sys.modules['M'] is not a real module; it's basically a getattr()
2264 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002265
2266 2) "from M import *" now looks for M.__all__ to decide which names to
2267 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2268 filters out names starting with '_' as before. Whether or not
2269 __all__ exists, there's no restriction on the type of M.
2270
Guido van Rossumf61f1662001-01-10 20:13:55 +00002271- File objects have a new method, xreadlines(). This is the fastest
2272 way to iterate over all lines in a file:
2273
2274 for line in file.xreadlines():
2275 ...do something to line...
2276
2277 See the xreadlines module (mentioned below) for how to do this for
2278 other file-like objects.
2279
2280- Even if you don't use file.xreadlines(), you may expect a speedup on
2281 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002282 quite a bit in platform-specific ways: on systems (like Linux) that
2283 support flockfile(), getc_unlocked(), and funlockfile(), those are
2284 used by default. On systems (like Windows) without getc_unlocked(),
2285 a complicated (but still thread-safe) method using fgets() is used by
2286 default.
2287
Tim Petersd52269b2001-01-25 06:23:18 +00002288 You can force use of the fgets() method by #define'ing
2289 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002290 getc_unlocked()).
2291
Tim Petersd52269b2001-01-25 06:23:18 +00002292 You can force fgets() not to be used by #define'ing
2293 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002294 test_bufio.py fails -- and let us know if it does!).
2295
2296- In addition, the fileinput module, while still slower than the other
2297 methods on most platforms, has been sped up too, by using
2298 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002299
2300- Support for run-time warnings has been added, including a new
2301 command line option (-W) to specify the disposition of warnings.
2302 See the description of the warnings module below.
2303
2304- Extensive changes have been made to the coercion code. This mostly
2305 affects extension modules (which can now implement mixed-type
2306 numerical operators without having to use coercion), but
2307 occasionally, in boundary cases the coercion semantics have changed
2308 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002309 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002310 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002311 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002312
Guido van Rossumf98eda02001-01-17 15:54:45 +00002313- In connection with the coercion changes, a new built-in singleton
2314 object, NotImplemented is defined. This can be returned for
2315 operations that wish to indicate they are not implemented for a
2316 particular combination of arguments. From C, this is
2317 Py_NotImplemented.
2318
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002319- The interpreter accepts now bytecode files on the command line even
2320 if they do not have a .pyc or .pyo extension. On Linux, after executing
2321
Martin v. Löwise214baa2001-02-04 22:37:56 +00002322import imp,sys,string
2323magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2324reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2325open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002326
2327 any byte code file can be used as an executable (i.e. as an argument
2328 to execve(2)).
2329
Tim Peters9940b802000-12-01 07:59:35 +00002330- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002331 character. In 1.6 and earlier, they never produced a sign,
2332 and raised an error if the value of the long was too large
2333 to fit in a Python int. In 2.0, they produced a sign if and
2334 only if too large to fit in an int. This was inconsistent
2335 across platforms (because the size of an int varies across
2336 platforms), and inconsistent with hex() and oct(). Example:
2337
2338 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002339 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002340 'ffffffbe' # in 2.0 and before, on 32-bit machines
2341 >>> hex(-0x42L)
2342 '-0x42L' # in all versions of Python
2343
Tim Peters9940b802000-12-01 07:59:35 +00002344 The behavior of %d formats for negative Python longs remains
2345 the same as in 2.0 (although in 1.6 and before, they raised
2346 an error if the long didn't fit in a Python int).
2347
2348 %u formats don't make sense for Python longs, but are allowed
2349 and treated the same as %d in 2.1. In 2.0, a negative long
2350 formatted via %u produced a sign if and only if too large to
2351 fit in an int. In 1.6 and earlier, a negative long formatted
2352 via %u raised an error if it was too big to fit in an int.
2353
Guido van Rossum3661d392000-12-12 22:10:31 +00002354- Dictionary objects have an odd new method, popitem(). This removes
2355 an arbitrary item from the dictionary and returns it (in the form of
2356 a (key, value) pair). This can be useful for algorithms that use a
2357 dictionary as a bag of "to do" items and repeatedly need to pick one
2358 item. Such algorithms normally end up running in quadratic time;
2359 using popitem() they can usually be made to run in linear time.
2360
Tim Peters36cdad12000-12-29 02:06:45 +00002361Standard library
2362
Thomas Woutersfe385252001-01-19 23:16:56 +00002363- In the time module, the time argument to the functions strftime,
2364 localtime, gmtime, asctime and ctime is now optional, defaulting to
2365 the current time (in the local timezone).
2366
Guido van Rossumda91f222001-01-15 16:36:08 +00002367- The ftplib module now defaults to passive mode, which is deemed a
2368 more useful default given that clients are often inside firewalls
2369 these days. Note that this could break if ftplib is used to connect
2370 to a *server* that is inside a firewall, from outside; this is
2371 expected to be a very rare situation. To fix that, you can call
2372 ftp.set_pasv(0).
2373
Martin v. Löwis10a27872001-01-13 09:54:41 +00002374- The module site now treats .pth files not only for path configuration,
2375 but also supports extensions to the initialization code: Lines starting
2376 with import are executed.
2377
Guido van Rossumf61f1662001-01-10 20:13:55 +00002378- There's a new module, warnings, which implements a mechanism for
2379 issuing and filtering warnings. There are some new built-in
2380 exceptions that serve as warning categories, and a new command line
2381 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2382 turns warnings into errors). warnings.warn(message[, category])
2383 issues a warning message; this can also be called from C as
2384 PyErr_Warn(category, message).
2385
2386- A new module xreadlines was added. This exports a single factory
2387 function, xreadlines(). The intention is that this code is the
2388 absolutely fastest way to iterate over all lines in an open
2389 file(-like) object:
2390
2391 import xreadlines
2392 for line in xreadlines.xreadlines(file):
2393 ...do something to line...
2394
2395 This is equivalent to the previous the speed record holder using
2396 file.readlines(sizehint). Note that if file is a real file object
2397 (as opposed to a file-like object), this is equivalent:
2398
2399 for line in file.xreadlines():
2400 ...do something to line...
2401
Tim Peters36cdad12000-12-29 02:06:45 +00002402- The bisect module has new functions bisect_left, insort_left,
2403 bisect_right and insort_right. The old names bisect and insort
2404 are now aliases for bisect_right and insort_right. XXX_right
2405 and XXX_left methods differ in what happens when the new element
2406 compares equal to one or more elements already in the list: the
2407 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002408 right. Code that doesn't care where equal elements end up should
2409 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002410
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002411- The new curses.panel module wraps the panel library that forms part
2412 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2413
Guido van Rossumf61f1662001-01-10 20:13:55 +00002414- The SocketServer module now sets the allow_reuse_address flag by
2415 default in the TCPServer class.
2416
2417- A new function, sys._getframe(), returns the stack frame pointer of
2418 the caller. This is intended only as a building block for
2419 higher-level mechanisms such as string interpolation.
2420
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002421- The pyexpat module supports a number of new handlers, which are
2422 available only in expat 1.2. If invocation of a callback fails, it
2423 will report an additional frame in the traceback. Parser objects
2424 participate now in garbage collection. If expat reports an unknown
2425 encoding, pyexpat will try to use a Python codec; that works only
2426 for single-byte charsets. The parser type objects is exposed as
2427 XMLParserObject.
2428
2429- xml.dom now offers standard definitions for symbolic node type and
2430 exception code constants, and a hierarchy of DOM exceptions. minidom
2431 was adjusted to use them.
2432
2433- The conformance of xml.dom.minidom to the DOM specification was
2434 improved. It detects a number of additional error cases; the
2435 previous/next relationship works even when the tree is modified;
2436 Node supports the normalize() method; NamedNodeMap, DocumentType and
2437 DOMImplementation classes were added; Element supports the
2438 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2439 method.
2440
Guido van Rossumf61f1662001-01-10 20:13:55 +00002441Build issues
2442
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002443- For Unix (and Unix-compatible) builds, configuration and building of
2444 extension modules is now greatly automated. Rather than having to
2445 edit the Modules/Setup file to indicate which modules should be
2446 built and where their include files and libraries are, a
2447 distutils-based setup.py script now takes care of building most
2448 extension modules. All extension modules built this way are built
2449 as shared libraries. Only a few modules that must be linked
2450 statically are still listed in the Setup file; you won't need to
2451 edit their configuration.
2452
2453- Python should now build out of the box on Cygwin. If it doesn't,
2454 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002455
2456- Python now always uses its own (renamed) implementation of getopt()
2457 -- there's too much variation among C library getopt()
2458 implementations.
2459
2460- C++ compilers are better supported; the CXX macro is always set to a
2461 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002462
Tim Petersd92dfe02000-12-12 01:18:41 +00002463Windows changes
2464
2465- select module: By default under Windows, a select() call
2466 can specify no more than 64 sockets. Python now boosts
2467 this Microsoft default to 512. If you need even more than
2468 that, see the MS docs (you'll need to #define FD_SETSIZE
2469 and recompile Python from source).
2470
Guido van Rossumf61f1662001-01-10 20:13:55 +00002471- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2472 subdirectory is no more!
2473
Tim Petersa3a3a032000-11-30 05:22:44 +00002474
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002475What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002476=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002477
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002478Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002479changes are in the file HISTORY. If you are making the jump directly
2480from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2481HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002482
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002483Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2484the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2485http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002486
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002487--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002488
2489======================================================================
2490
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002491What's new in 2.0 (since release candidate 1)?
2492==============================================
2493
2494Standard library
2495
2496- The copy_reg module was modified to clarify its intended use: to
2497 register pickle support for extension types, not for classes.
2498 pickle() will raise a TypeError if it is passed a class.
2499
2500- Fixed a bug in gettext's "normalize and expand" code that prevented
2501 it from finding an existing .mo file.
2502
2503- Restored support for HTTP/0.9 servers in httplib.
2504
Tim Peters989b7b92000-10-16 20:24:53 +00002505- The math module was changed to stop raising OverflowError in case of
2506 underflow, and return 0 instead in underflow cases. Whether Python
2507 used to raise OverflowError in case of underflow was platform-
2508 dependent (it did when the platform math library set errno to ERANGE
2509 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002510
2511- Fixed a bug in StringIO that occurred when the file position was not
2512 at the end of the file and write() was called with enough data to
2513 extend past the end of the file.
2514
2515- Fixed a bug that caused Tkinter error messages to get lost on
2516 Windows. The bug was fixed by replacing direct use of
2517 interp->result with Tcl_GetStringResult(interp).
2518
2519- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2520 redirect response.
2521
2522- Several changes were made to distutils: Some debugging code was
2523 removed from util. Fixed the installer used when an external zip
2524 program (like WinZip) is not found; the source code for this
2525 installer is in Misc/distutils. check_lib() was modified to behave
2526 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2527 test for whether installed modules are on sys.path was changed to
2528 use both normcase() and normpath().
2529
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002530- Several minor bugs were fixed in the xml package (the minidom,
2531 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002532
2533- The regression test driver (regrtest.py) behavior when invoked with
2534 -l changed: It now reports a count of objects that are recognized as
2535 garbage but not freed by the garbage collector.
2536
Tim Peters989b7b92000-10-16 20:24:53 +00002537- The regression test for the math module was changed to test
2538 exceptional behavior when the test is run in verbose mode. Python
2539 cannot yet guarantee consistent exception behavior across platforms,
2540 so the exception part of test_math is run only in verbose mode, and
2541 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002542
2543Internals
2544
2545- PyOS_CheckStack() has been disabled on Win64, where it caused
2546 test_sre to fail.
2547
2548Build issues
2549
2550- Changed compiler flags, so that gcc is always invoked with -Wall and
2551 -Wstrict-prototypes. Users compiling Python with GCC should see
2552 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002553 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002554 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002555
Tim Petersa3a3a032000-11-30 05:22:44 +00002556- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002557
2558Tools and other miscellany
2559
2560- The compiler in Tools/compiler was updated to support the new
2561 language features introduced in 2.0: extended print statement, list
2562 comprehensions, and augmented assignments. The new compiler should
2563 also be backwards compatible with Python 1.5.2; the compiler will
2564 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002565 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002566
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002567What's new in 2.0 release candidate 1 (since beta 2)?
2568=====================================================
2569
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002570What is release candidate 1?
2571
2572We believe that release candidate 1 will fix all known bugs that we
2573intend to fix for the 2.0 final release. This release should be a bit
2574more stable than the previous betas. We would like to see even more
2575widespread testing before the final release, so we are producing this
2576release candidate. The final release will be exactly the same unless
2577any show-stopping (or brown bag) bugs are found by testers of the
2578release candidate.
2579
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002580All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002581to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002582
2583Core language, builtins, and interpreter
2584
2585- A bug that caused crashes when __coerce__ was used with augmented
2586 assignment, e.g. +=, was fixed.
2587
2588- Raise ZeroDivisionError when raising zero to a negative number,
2589 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2590 power operator and the result of math.pow(0.0, -2.0) will vary by
2591 platform. On Linux, it raises a ValueError.
2592
2593- A bug in Unicode string interpolation was fixed that occasionally
2594 caused errors with formats including "%%". For example, the
2595 following expression "%% %s" % u"abc" no longer raises a TypeError.
2596
2597- Compilation of deeply nested expressions raises MemoryError instead
2598 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2599
2600- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2601 rendering them useless. They are now written in binary mode again.
2602
2603Standard library
2604
2605- Keyword arguments are now accepted for most pattern and match object
2606 methods in SRE, the standard regular expression engine.
2607
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002608- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002609 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002610
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002611- Several bugs in the Unicode handling and error handling in _tkinter
2612 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002613
2614- Fix memory management errors in Merge() and Tkapp_Call() routines.
2615
2616- Several changes were made to cStringIO to make it compatible with
2617 the file-like object interface and with StringIO. If operations are
2618 performed on a closed object, an exception is raised. The truncate
2619 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002620 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002621
2622- There were many changes made to the linuxaudiodev module and its
2623 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002624 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002625
2626 Note that this module is named poorly, because it should work
2627 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002628 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002629
2630 The module now raises exceptions when errors occur instead of
2631 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2632 audio) and defines a getptr() method that calls the
2633 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2634
2635- The library_version attribute, introduced in an earlier beta, was
2636 removed because it can not be supported with early versions of the C
2637 readline library, which provides no way to determine the version at
2638 compile-time.
2639
2640- The binascii module is now enabled on Win64.
2641
Tim Peters46446d62000-10-09 21:19:31 +00002642- tokenize.py no longer suffers "recursion depth" errors when parsing
2643 programs with very long string literals.
2644
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002645Internals
2646
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002647- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002648 which is called when the interpreter starts up to determine where
2649 the standard library is installed. These vulnerabilities affect all
2650 previous versions of Python and can be exploited by setting very
2651 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2652 setuid Python script, although use of the wrapper in
2653 Misc/setuid-prog.c will eliminate the vulnerability.
2654
2655- Fixed garbage collection bugs in instance creation that were
2656 triggered when errors occurred during initialization. The solution,
2657 applied in cPickle and in PyInstance_New(), is to call
2658 PyObject_GC_Init() after the initialization of the object's
2659 container attributes is complete.
2660
2661- pyexpat adds definitions of PyModule_AddStringConstant and
2662 PyModule_AddObject if the Python version is less than 2.0, which
2663 provides compatibility with PyXML on Python 1.5.2.
2664
2665- If the platform has a bogus definition for LONG_BIT (the number of
2666 bits in a long), an error will be reported at compile time.
2667
2668- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2669 collection crashes and possibly other, unreported crashes.
2670
2671- Fixed a memory leak in _PyUnicode_Fini().
2672
2673Build issues
2674
2675- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002676 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002677 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002678
2679- The mmap.PAGESIZE constant is now initialized using sysconf when
2680 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2681
2682- The md5 file should now compile on all platforms.
2683
2684- The select module now compiles on platforms that do not define
2685 POLLRDNORM and related constants.
2686
2687- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002688 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002689
Jeremy Hylton10921202000-10-09 18:34:12 +00002690- BeOS: A number of changes were made to the build and installation
2691 process. ar-fake now operates on a directory of object files.
2692 dl_export.h is gone, and its macros now appear on the mwcc command
2693 line during build on PPC BeOS.
2694
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002695- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002696 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002697
2698- Cygwin: Support for shared libraries, Tkinter, and sockets.
2699
2700- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2701
2702Tools and other miscellany
2703
2704- Removed debugging prints from main used with freeze.
2705
Tim Peters46446d62000-10-09 21:19:31 +00002706- IDLE auto-indent no longer crashes when it encounters Unicode
2707 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002708
2709What's new in 2.0 beta 2 (since beta 1)?
2710========================================
2711
2712Core language, builtins, and interpreter
2713
Tim Peters482c0212000-09-26 06:33:09 +00002714- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002715 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002716
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002717- Add -h and -V command line options to print the usage message and
2718 Python version number and exit immediately.
2719
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002720- eval() and exec accept Unicode objects as code parameters.
2721
2722- getattr() and setattr() now also accept Unicode objects for the
2723 attribute name, which are converted to strings using the default
2724 encoding before lookup.
2725
2726- Multiplication on string and Unicode now does proper bounds
2727 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2728 string is too long."
2729
2730- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002731 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002732
Jeremy Hylton1b618592000-09-26 05:32:36 +00002733
2734Standard library and extensions
2735
Guido van Rossum5b08f132001-04-16 02:05:23 +00002736- socket module: the OpenSSL code now adds support for RAND_status()
2737 and EGD (Entropy Gathering Device).
2738
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002739- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002740 argument checking; it still takes no arguments.
2741
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002742- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002743
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002744- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002745
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002746- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002747
2748- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002749 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002750
2751- copy: Copy Unicode objects atomically.
2752
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002753- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002754
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002755- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002756
Fred Drake67233bc2000-09-26 16:40:27 +00002757- dbm: Add get() and setdefault() methods to dbm object. Add constant
2758 `library' to module that names the library used. Added doc strings
2759 and method names to error messages. Uses configure to determine
2760 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2761 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002762
2763- distutils: Update to version 0.9.3.
2764
2765- dl: Add several dl.RTLD_ constants.
2766
2767- fpectl: Now supported on FreeBSD.
2768
2769- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2770 found by the collector will be saved in gc.garbage. This is useful
2771 for debugging a program that creates reference cycles.
2772
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002773- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002774 of HTTP class. Do not close socket on zero-length response. Do not
2775 crash when server sends invalid content-length header.
2776
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002777- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002779- marshal: When reading a short, sign-extend on platforms where shorts
2780 are bigger than 16 bits. When reading a long, repair the unportable
2781 sign extension that was being done for 64-bit machines. (It assumed
2782 that signed right shift sign-extends.)
2783
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002784- operator: Add contains(), invert(), __invert__() as aliases for
2785 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002786
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002787- os: Add support for popen2() and popen3() on all platforms where
2788 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002789
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002790- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002791 clicking on a file in Explorer (or passing the file name to the
2792 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002794- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002795 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002796
2797- pickle: Now raises ValueError when an invalid pickle that contains
2798 a non-string repr where a string repr was expected. This behavior
2799 matches cPickle.
2800
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002801- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002802
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002803- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002804
2805- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002806 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002807 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002808
2809- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002810 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002811
2812- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002813 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002814 few cycles during startup since the first call to
2815 setdefaultencoding() will initialize the codec registry and the
2816 encodings package.
2817
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002818- socket: Support for size hint in readlines() method of object returned
2819 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002820
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002821- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002822 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002823 is followed by whitespace.
2824
Tim Petersa3a3a032000-11-30 05:22:44 +00002825- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002826
2827- struct: Check ranges for bytes and shorts.
2828
2829- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002830 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002831
2832- Tkinter: Image objects are now guaranteed to have unique ids. Set
2833 event.delta to zero if Tk version doesn't support mousewheel.
2834 Removed some debugging prints.
2835
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002836- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002837
Fred Drake67233bc2000-09-26 16:40:27 +00002838- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002839 which works around a bug in Norton AntiVirus 2000 that leads directly
2840 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841
2842- xml: New version detection code allows PyXML to override standard
2843 XML package if PyXML version is greater than 0.6.1.
2844
Fred Drake64bb3802000-09-26 16:21:35 +00002845- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2846 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2847 tree only for nodes which are sufficiently interesting to a specific
2848 application. Does not provide the HTML-specific extensions. Still
2849 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002850
Fred Drake64bb3802000-09-26 16:21:35 +00002851- xml.sax: SAX 2 support for Python, including all the handler
2852 interfaces needed to process XML 1.0 compliant XML. Some
2853 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002854
Fred Drake64bb3802000-09-26 16:21:35 +00002855- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2856 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002857
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002858
Jeremy Hylton1b618592000-09-26 05:32:36 +00002859C API
2860
2861- Add three new convenience functions for module initialization --
2862 PyModule_AddObject(), PyModule_AddIntConstant(), and
2863 PyModule_AddStringConstant().
2864
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002865- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002866 removed and add #error to Python.h if NULL isn't defined after
2867 #include of stdio.h.
2868
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002869- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002870 backwards compatibility (at the source level) with old extensions.
2871
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002872- A wrapper API was added for signal() and sigaction(). Instead of
2873 either function, always use PyOS_getsig() to get a signal handler
2874 and PyOS_setsig() to set one. A new convenience typedef
2875 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002876
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002877- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878 internal data buffer and size of a string object -- or the default
2879 encoded version of a Unicode object.
2880
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002881- PyString_Size() and PyString_AsString() accept Unicode objects.
2882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002883- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002884 exists). INT_MAX and LONG_MAX will always be defined, even if
2885 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002886
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002887- PyFloat_FromString takes a second argument, pend, that was
2888 effectively useless. It is now officially useless but preserved for
2889 backwards compatibility. If the pend argument is not NULL, *pend is
2890 set to NULL.
2891
2892- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2893 for the attribute name. See note on getattr() above.
2894
2895- A few bug fixes to argument processing for Unicode.
2896 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2897 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2898 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002899 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002900
2901- Py_BuildValue accepts B format (for bgen-generated code).
2902
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002903
Jeremy Hylton1b618592000-09-26 05:32:36 +00002904Internals
2905
2906- On Unix, fix code for finding Python installation directory so that
2907 it works when argv[0] is a relative path.
2908
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002909- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002910 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002911 rather than by generating a copy of the object.
2912
Tim Peters482c0212000-09-26 06:33:09 +00002913- Several of the internal Unicode tables are much smaller now, and
2914 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002915
Jeremy Hylton97693b02000-09-26 17:42:51 +00002916- In the garbage collector: Fixed bug in collection of tuples. Fixed
2917 bug that caused some instances to be removed from the container set
2918 while they were still live. Fixed parsing in gc.set_debug() for
2919 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002920
2921- Fixed refcount problem in instance deallocation that only occurred
2922 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2923
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002924- On Windows, getpythonregpath is now protected against null data in
2925 registry key.
2926
2927- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002928 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002929
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002930
Jeremy Hylton1b618592000-09-26 05:32:36 +00002931Build and platform-specific issues
2932
2933- Better support of GNU Pth via --with-pth configure option.
2934
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002935- Python/C API now properly exposed to dynamically-loaded extension
2936 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002937
2938- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2939 Don't define MS_SYNC to be zero when it is undefined. Added missing
2940 prototypes in posixmodule.c.
2941
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002942- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002943 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002944
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002945- Fix largefile support on older NetBSD systems and OpenBSD by adding
2946 define for TELL64.
2947
2948
2949Tools and other miscellany
2950
2951- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2952
2953- freeze: The modulefinder now works with 2.0 opcodes.
2954
Tim Petersa3a3a032000-11-30 05:22:44 +00002955- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002956 Move hackery of sys.argv until after the Tk instance has been
2957 created, which allows the application-specific Tkinter
2958 initialization to be executed if present; also pass an explicit
2959 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002960
Jeremy Hylton1b618592000-09-26 05:32:36 +00002961
2962What's new in 2.0 beta 1?
2963=========================
2964
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002965Source Incompatibilities
2966------------------------
2967
2968None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2969such as single-argument append(), connect() and bind(), and changes to
2970str(long) and repr(float).
2971
2972
2973Binary Incompatibilities
2974------------------------
2975
2976- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2977with Python 2.0; these extensions will have to be rebuilt for Python
29782.0.
2979
2980- On Windows, attempting to import a third party extension built for
2981Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2982can do about this. Check your PYTHONPATH environment variable!
2983
2984- Python bytecode files (*.pyc and *.pyo) are not compatible between
2985releases.
2986
2987
2988Overview of Changes Since 1.6
2989-----------------------------
2990
2991There are many new modules (including brand new XML support through
2992the xml package, and i18n support through the gettext module); a list
2993of all new modules is included below. Lots of bugs have been fixed.
2994
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002995The process for making major new changes to the language has changed
2996since Python 1.6. Enhancements must now be documented by a Python
2997Enhancement Proposal (PEP) before they can be accepted.
2998
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002999There are several important syntax enhancements, described in more
3000detail below:
3001
3002 - Augmented assignment, e.g. x += 1
3003
3004 - List comprehensions, e.g. [x**2 for x in range(10)]
3005
3006 - Extended import statement, e.g. import Module as Name
3007
3008 - Extended print statement, e.g. print >> file, "Hello"
3009
3010Other important changes:
3011
3012 - Optional collection of cyclical garbage
3013
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003014Python Enhancement Proposal (PEP)
3015---------------------------------
3016
3017PEP stands for Python Enhancement Proposal. A PEP is a design
3018document providing information to the Python community, or describing
3019a new feature for Python. The PEP should provide a concise technical
3020specification of the feature and a rationale for the feature.
3021
3022We intend PEPs to be the primary mechanisms for proposing new
3023features, for collecting community input on an issue, and for
3024documenting the design decisions that have gone into Python. The PEP
3025author is responsible for building consensus within the community and
3026documenting dissenting opinions.
3027
3028The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003029
3030Augmented Assignment
3031--------------------
3032
3033This must have been the most-requested feature of the past years!
3034Eleven new assignment operators were added:
3035
Guido van Rossume905e952000-09-05 12:42:46 +00003036 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003037
3038For example,
3039
3040 A += B
3041
3042is similar to
3043
3044 A = A + B
3045
3046except that A is evaluated only once (relevant when A is something
3047like dict[index].attr).
3048
3049However, if A is a mutable object, A may be modified in place. Thus,
3050if A is a number or a string, A += B has the same effect as A = A+B
3051(except A is only evaluated once); but if a is a list, A += B has the
3052same effect as A.extend(B)!
3053
3054Classes and built-in object types can override the new operators in
3055order to implement the in-place behavior; the not-in-place behavior is
3056used automatically as a fallback when an object doesn't implement the
3057in-place behavior. For classes, the method name is derived from the
3058method name for the corresponding not-in-place operator by inserting
3059an 'i' in front of the name, e.g. __iadd__ implements in-place
3060__add__.
3061
3062Augmented assignment was implemented by Thomas Wouters.
3063
3064
3065List Comprehensions
3066-------------------
3067
3068This is a flexible new notation for lists whose elements are computed
3069from another list (or lists). The simplest form is:
3070
3071 [<expression> for <variable> in <sequence>]
3072
Guido van Rossum56db0952000-09-06 23:34:25 +00003073For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003074This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003075
3076You can also add a condition:
3077
3078 [<expression> for <variable> in <sequence> if <condition>]
3079
3080For example, [w for w in words if w == w.lower()] would yield the list
3081of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003082than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003083
3084You can also have nested for loops and more than one 'if' clause. For
3085example, here's a function that flattens a sequence of sequences::
3086
3087 def flatten(seq):
3088 return [x for subseq in seq for x in subseq]
3089
3090 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3091
3092This prints
3093
3094 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3095
3096List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003097Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003098
3099
3100Extended Import Statement
3101-------------------------
3102
3103Many people have asked for a way to import a module under a different
3104name. This can be accomplished like this:
3105
3106 import foo
3107 bar = foo
3108 del foo
3109
3110but this common idiom gets old quickly. A simple extension of the
3111import statement now allows this to be written as follows:
3112
3113 import foo as bar
3114
3115There's also a variant for 'from ... import':
3116
3117 from foo import bar as spam
3118
3119This also works with packages; e.g. you can write this:
3120
3121 import test.regrtest as regrtest
3122
3123Note that 'as' is not a new keyword -- it is recognized only in this
3124context (this is only possible because the syntax for the import
3125statement doesn't involve expressions).
3126
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003127Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003128
3129
3130Extended Print Statement
3131------------------------
3132
3133Easily the most controversial new feature, this extension to the print
3134statement adds an option to make the output go to a different file
3135than the default sys.stdout.
3136
3137For example, to write an error message to sys.stderr, you can now
3138write:
3139
3140 print >> sys.stderr, "Error: bad dog!"
3141
3142As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003143evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003144
3145 print >> None, "Hello world"
3146
3147is equivalent to
3148
3149 print "Hello world"
3150
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003151Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003152
3153
3154Optional Collection of Cyclical Garbage
3155---------------------------------------
3156
3157Python is now equipped with a garbage collector that can hunt down
3158cyclical references between Python objects. It's no replacement for
3159reference counting; in fact, it depends on the reference counts being
3160correct, and decides that a set of objects belong to a cycle if all
3161their reference counts can be accounted for from their references to
3162each other. This devious scheme was first proposed by Eric Tiedemann,
3163and brought to implementation by Neil Schemenauer.
3164
3165There's a module "gc" that lets you control some parameters of the
3166garbage collection. There's also an option to the configure script
3167that lets you enable or disable the garbage collection. In 2.0b1,
3168it's on by default, so that we (hopefully) can collect decent user
3169experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003170performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003171off by default in the final 2.0 release.
3172
3173
3174Smaller Changes
3175---------------
3176
3177A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3178map(None, seq1, seq2, ...) when the sequences have the same length;
3179i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3180the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003181zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003182
3183sys.version_info is a tuple (major, minor, micro, level, serial).
3184
3185Dictionaries have an odd new method, setdefault(key, default).
3186dict.setdefault(key, default) returns dict[key] if it exists; if not,
3187it sets dict[key] to default and returns that value. Thus:
3188
3189 dict.setdefault(key, []).append(item)
3190
3191does the same work as this common idiom:
3192
3193 if not dict.has_key(key):
3194 dict[key] = []
3195 dict[key].append(item)
3196
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003197There are two new variants of SyntaxError that are raised for
3198indentation-related errors: IndentationError and TabError.
3199
3200Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3201escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003202
3203The limits on the size of expressions and file in Python source code
3204have been raised from 2**16 to 2**32. Previous versions of Python
3205were limited because the maximum argument size the Python VM accepted
3206was 2**16. This limited the size of object constructor expressions,
3207e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3208limit was raised thanks to a patch by Charles Waldman that effectively
3209fixes the problem. It is now much more likely that you will be
3210limited by available memory than by an arbitrary limit in Python.
3211
3212The interpreter's maximum recursion depth can be modified by Python
3213programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3214limit is the maximum number of recursive calls that can be made by
3215Python code. The limit exists to prevent infinite recursion from
3216overflowing the C stack and causing a core dump. The default value is
32171000. The maximum safe value for a particular platform can be found
3218by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003219
3220New Modules and Packages
3221------------------------
3222
3223atexit - for registering functions to be called when Python exits.
3224
3225imputil - Greg Stein's alternative API for writing custom import
3226hooks.
3227
3228pyexpat - an interface to the Expat XML parser, contributed by Paul
3229Prescod.
3230
3231xml - a new package with XML support code organized (so far) in three
3232subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3233would fill a volume. There's a special feature whereby a
3234user-installed package named _xmlplus overrides the standard
3235xmlpackage; this is intended to give the XML SIG a hook to distribute
3236backwards-compatible updates to the standard xml package.
3237
3238webbrowser - a platform-independent API to launch a web browser.
3239
3240
Guido van Rossume905e952000-09-05 12:42:46 +00003241Changed Modules
3242---------------
3243
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003244array -- new methods for array objects: count, extend, index, pop, and
3245remove
3246
3247binascii -- new functions b2a_hex and a2b_hex that convert between
3248binary data and its hex representation
3249
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003250calendar -- Many new functions that support features including control
3251over which day of the week is the first day, returning strings instead
3252of printing them. Also new symbolic constants for days of week,
3253e.g. MONDAY, ..., SUNDAY.
3254
3255cgi -- FieldStorage objects have a getvalue method that works like a
3256dictionary's get method and returns the value attribute of the object.
3257
3258ConfigParser -- The parser object has new methods has_option,
3259remove_section, remove_option, set, and write. They allow the module
3260to be used for writing config files as well as reading them.
3261
3262ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003263optionally support the RFC 959 REST command.
3264
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003265gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003266
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003267httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3268the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003269
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003270locale -- implement getdefaultlocale for Win32 and Macintosh
3271
3272marshal -- no longer dumps core when marshaling deeply nested or
3273recursive data structures
3274
3275os -- new functions isatty, seteuid, setegid, setreuid, setregid
3276
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003277os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3278support under Unix.
3279
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003280os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003281
3282os.path -- fix semantics of os.path.commonprefix
3283
3284smtplib -- support for sending very long messages
3285
3286socket -- new function getfqdn()
3287
3288readline -- new functions to read, write and truncate history files.
3289The readline section of the library reference manual contains an
3290example.
3291
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003292select -- add interface to poll system call
3293
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003294shutil -- new copyfileobj function
3295
3296SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3297HTTP server.
3298
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003299Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003300
3301urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003302e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003303
3304whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003305
3306
3307Obsolete Modules
3308----------------
3309
3310None. However note that 1.6 made a whole slew of modules obsolete:
3311stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3312poly, zmod, strop, util, whatsound.
3313
3314
3315Changed, New, Obsolete Tools
3316----------------------------
3317
Tim Peters8b092332000-09-05 20:15:25 +00003318None.
Guido van Rossume905e952000-09-05 12:42:46 +00003319
3320
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003321C-level Changes
3322---------------
3323
3324Several cleanup jobs were carried out throughout the source code.
3325
3326All C code was converted to ANSI C; we got rid of all uses of the
3327Py_PROTO() macro, which makes the header files a lot more readable.
3328
3329Most of the portability hacks were moved to a new header file,
3330pyport.h; several other new header files were added and some old
3331header files were removed, in an attempt to create a more rational set
3332of header files. (Few of these ever need to be included explicitly;
3333they are all included by Python.h.)
3334
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003335Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003336and Win64, especially for the new Intel Itanium processor. Mick also
3337added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003338
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003339The C APIs to return an object's size have been update to consistently
3340use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3341previous versions, the abstract interfaces used PyXXX_Length and the
3342concrete interfaces used PyXXX_Size. The old names,
3343e.g. PyObject_Length, are still available for backwards compatibility
3344at the API level, but are deprecated.
3345
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003346The PyOS_CheckStack function has been implemented on Windows by
3347Fredrik Lundh. It prevents Python from failing with a stack overflow
3348on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003349
3350The GC changes resulted in creation of two new slots on object,
3351tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003352the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003353
3354The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003355C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003356
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003357PyErr_Format has been updated to automatically calculate the size of
3358the buffer needed to hold the formatted result string. This change
3359prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003360
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003361New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003362
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003363PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3364that are the same as their non-Ex counterparts except they take an
3365extra flag argument that tells them to close the file when done.
3366
3367XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003368
Tim Peters8b092332000-09-05 20:15:25 +00003369
3370Windows Changes
3371---------------
3372
3373New popen2/popen3/peopen4 in os module (see Changed Modules above).
3374
3375os.popen is much more usable on Windows 95 and 98. See Microsoft
3376Knowledge Base article Q150956. The Win9x workaround described there
3377is implemented by the new w9xpopen.exe helper in the root of your
3378Python installation. Note that Python uses this internally; it is not
3379a standalone program.
3380
3381Administrator privileges are no longer required to install Python
3382on Windows NT or Windows 2000. If you have administrator privileges,
3383Python's registry info will be written under HKEY_LOCAL_MACHINE.
3384Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003385under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003386uses of Python, but will prevent some advanced uses from working
3387(for example, running a Python script as an NT service, or possibly
3388from CGI).
3389
3390[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3391installer; instead, it installs the needed Tcl/Tk files directly in the
3392Python directory. If you already have a Tcl/Tk installation, this
3393wastes some disk space (about 4 Megs) but avoids problems with
3394conflicting Tcl/Tk installations, and makes it much easier for Python
3395to ensure that Tcl/Tk can find all its files.
3396
3397[This was new in 1.6] The Windows installer now installs by default in
3398\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3399
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003400
3401Updates to the changes between 1.5.2 and 1.6
3402--------------------------------------------
3403
3404The 1.6 NEWS file can't be changed after the release is done, so here
3405is some late-breaking news:
3406
3407New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3408and changes to getlocale() and setlocale().
3409
3410The new module is now enabled per default.
3411
3412It is not true that the encodings codecs cannot be used for normal
3413strings: the string.encode() (which is also present on 8-bit strings
3414!) allows using them for 8-bit strings too, e.g. to convert files from
3415cp1252 (Windows) to latin-1 or vice-versa.
3416
3417Japanese codecs are available from Tamito KAJIYAMA:
3418http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3419
3420
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003421======================================================================