blob: 400b63161e3290bfbe1c99226a30b82531cd1c0b [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
7Core and builtins
8
Guido van Rossum862fe3c2002-04-15 12:36:47 +00009- Complex numbers supported divmod() and the // and % operators, but
10 these make no sense. Since this was documented, they're being
11 deprecated now.
12
Guido van Rossum49042042002-04-13 00:59:05 +000013- String methods lstrip(), rstrip() and strip() now take an optional
14 argument that specifies the characters to strip. For example,
15 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
16
Guido van Rossumc69343b2002-04-12 19:22:48 +000017- Added a new dict method pop(key). This removes and returns the
18 value corresponding to key. [SF patch #539949]
19
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000020- Changed new-style class instantiation so that when C's __new__
21 method returns something that's not a C instance, its __init__ is
22 not called. [SF bug #537450]
23
Guido van Rossum181e41a2002-04-06 00:23:25 +000024- Fixed super() to work correctly with class methods. [SF bug #535444]
25
Guido van Rossum47834462002-04-04 15:21:33 +000026- A new built-in type, bool, has been added, as well as built-in
27 names for its two values, True and False. Comparisons and sundry
28 other operations that return a truth value have been changed to
29 return a bool instead. Read PEP 285 for an explanantion of why this
30 is backward compatible.
31
Guido van Rossum95b62a62002-03-29 01:07:24 +000032- Fixed two bugs reported as SF #535905: under certain conditions,
33 deallocating a deeply nested structure could cause a segfault in the
34 garbage collector, due to interaction with the "trashcan" code;
35 access to the current frame during destruction of a local variable
36 could access a pointer to freed memory.
37
Neil Schemenauer9d50d132002-03-22 17:06:59 +000038- The optional object allocator has been enabled by default.
39
Guido van Rossum8c842552002-03-14 23:05:54 +000040- If you try to pickle an instance of a class that has __slots__ but
41 doesn't define or override __getstate__, a TypeError is now raised.
42 This is done by adding a bozo __getstate__ to the class that always
43 raises TypeError. (Before, this would appear to be pickled, but the
44 state of the slots would be lost.)
45
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000046- PyErr_Display will provide file and line information for all exceptions
47 that have an attribute print_file_and_line, not just SyntaxErrors.
48
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000049- The UTF-8 codec will now encode and decode Unicode surrogates
50 correctly and without raising exceptions for unpaired ones.
51
Neal Norwitz649b7592002-01-01 19:07:13 +000052- file.xreadlines() now raises a ValueError if the file is closed:
53 Previously, an xreadlines object was returned which would raise
54 a ValueError when the xreadlines.next() method was called.
55
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000056- posix.killpg has been added where available.
57
Neal Norwitz0c766a02002-03-27 13:03:09 +000058- sys.exit() inadvertantly allowed more than one argument.
59 An exception will now be raised if more than one argument is used.
60
Tim Petersaf8446f2001-12-21 21:36:50 +000061Extension modules
62
Martin v. Löwis06a83e92002-04-14 10:19:44 +000063- posix.mknod was added.
64
Martin v. Löwis2e64c342002-03-27 18:49:02 +000065- The locale module now exposes the C library's gettext interface.
66
Tim Petersfbf74f22002-03-14 19:06:01 +000067- A security hole ("double free") was found in zlib-1.1.3, a popular
68 third party compression library used by some Python modules. The
69 hole was quickly plugged in zlib-1.1.4, and the Windows build of
70 Python now ships with zlib-1.1.4.
71
Martin v. Löwis688357e2002-04-08 21:28:20 +000072- pwd, grp, and resource return enhanced tuples now, with symbolic
73 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000074
Martin v. Löwis99866332002-03-01 10:27:01 +000075- array.array is now a type object. A new format character
76 'u' indicates Py_UNICODE arrays. For those, .tounicode and
77 .fromunicode methods are available. Arrays now support __iadd__
78 and __imul__.
79
Neal Norwitze790eae2002-01-01 21:14:12 +000080- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000081 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
82 is called.
83
Tim Petersaf8446f2001-12-21 21:36:50 +000084Library
85
Marc-André Lemburg4179a012002-04-05 12:15:05 +000086- The UTF-16, -LE and -BE now raise a NotImplementedError
87 for all calls to .readline(). Previously, they used to just
88 produce garbage or fail with an encoding error -- UTF-16 is
89 a 2-byte encoding and the C lib's line reading APIs don't
90 work well with these.
91
Martin v. Löwis5c137c22002-03-18 12:44:08 +000092- compileall now supports quiet operation.
93
Martin v. Löwis587c98c2002-03-17 18:37:22 +000094- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
95 connections.
96
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +000097- socket module: the SSL support was broken out of the main
98 _socket module C helper and placed into a new _ssl helper
99 which now gets imported by socket.py if available and working.
100
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000101- encodings package: added aliases for all supported IANA character
102 sets
103
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000104- ftplib: to safeguard the user's privacy, anonymous login will use
105 "anonymous@" as default password, rather than the real user and host
106 name.
107
Fred Drake36736122002-01-10 13:50:31 +0000108- webbrowser: tightened up the command passed to os.system() so that
109 arbitrary shell code can't be executed because a bogus URL was
110 passed in.
111
Tim Peters11bd9942002-02-01 00:52:29 +0000112- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000113 gettext.find an optional all argument. Translations will now fallback
114 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000115
Martin v. Löwis9668b932002-01-12 11:27:42 +0000116- distutils bdist commands now offer a --skip-build option.
117
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000118- warnings.warn now accepts a Warning instance as first argument.
119
Fred Drakefed7e852002-04-04 19:36:15 +0000120- The xml.sax.expatreader.ExpatParser class will no longer create
121 circular references by using itself as the locator that gets passed
122 to the content handler implementation. [SF bug #535474]
123
Tim Petersaf8446f2001-12-21 21:36:50 +0000124Tools/Demos
125
Marc-André Lemburg46260092002-04-04 16:17:11 +0000126- freeze.py now produces binaries which can import shared modules,
127 unlike before when this failed due to missing symbol exports in
128 the generated binary.
129
Tim Petersaf8446f2001-12-21 21:36:50 +0000130Build
131
Martin v. Löwis1142de32002-03-29 16:28:31 +0000132- On Unix, a shared libpython2.3.so can be created with --enable-shared.
133
Tim Peters8deda702002-03-30 10:06:07 +0000134- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
135 preprocessor symbols were eliminated. The internal decisions they
136 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000137
Tim Petersaf8446f2001-12-21 21:36:50 +0000138C API
139
Neil Schemenauer9344b142002-04-12 23:00:08 +0000140- The type of tp_free has been changed from "void (*)(PyObject *)" to
141 "void (*)(void *)".
142
143- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
144
Guido van Rossum0986d822002-04-08 01:38:42 +0000145- A type can now inherit its metatype from its base type. Previously,
146 when PyType_Ready() was called, if ob_type was found to be NULL, it
147 was always set to &PyType_Type; now it is set to base->ob_type,
148 where base is tp_base, defaulting to &PyObject_Type.
149
150- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
151
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000152- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
153 functions will be allocated using pymalloc if it is enabled. These
154 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
155 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
156 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
157 PyCore_* family of APIs have been removed.
158
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000159- The "u#" parser marker will now pass through Unicode object as-is
160 without going through the buffer API.
161
Martin v. Löwis7198a522002-01-01 19:59:11 +0000162- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
163
Tim Peters10a3bb52001-12-25 19:07:38 +0000164- An old #define of ANY as void has been removed from pyport.h. This
165 hasn't been used since Python's pre-ANSI days, and the #define has
166 been marked as obsolete since then. SF bug 495548 says it created
167 conflicts with other packages, so keeping it around wasn't harmless.
168
Tim Petersaf8446f2001-12-21 21:36:50 +0000169- Because Python's magic number scheme broke on January 1st, we decided
170 to stop Python development. Thanks for all the fish!
171
Tim Petersfb05db22002-03-11 00:24:00 +0000172- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000173 scheme to a new one. See Python/import.c for details.
174
Tim Petersaf8446f2001-12-21 21:36:50 +0000175New platforms
176
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000177- GNU/Hurd is now supported.
178
Tim Petersaf8446f2001-12-21 21:36:50 +0000179Tests
180
181Windows
182
Guido van Rossum181e41a2002-04-06 00:23:25 +0000183- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
184
Tim Peters33187922002-04-04 20:02:04 +0000185- The installer now installs Start menu shortcuts under (the local
186 equivalent of) "All Users" when doing an Admin install.
187
Tim Petersfb05db22002-03-11 00:24:00 +0000188- file.truncate([newsize]) now works on Windows for all newsize values.
189 It used to fail if newsize didn't fit in 32 bits, reflecting a
190 limitation of MS _chsize (which is no longer used).
191
Tim Petersab034fa2002-02-01 11:27:43 +0000192- os.waitpid() is now implemented for Windows, and can be used to block
193 until a specified process exits. This is similar to, but not exactly
194 the same as, os.waitpid() on POSIX systems. If you're waiting for
195 a specific process whose pid was obtained from one of the spawn()
196 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000197 See the docs for details. The docs were changed to clarify that
198 spawn functions return, and waitpid requires, a process handle on
199 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000200
Tim Peters11bd9942002-02-01 00:52:29 +0000201- New tempfile.TemporaryFile implementation for Windows: this doesn't
202 need a TemproraryFileWrapper wrapper anymore, and should be immune
203 to a nasty problem: before 2.3, if you got a temp file on Windows, it
204 got wrapped in an object whose close() method first closed the
205 underlying file, then deleted the file. This usually worked fine.
206 However, the spawn family of functions on Windows create (at a low C
207 level) the same set of open files in the spawned process Q as were
208 open in the spawning process P. If a temp file f was among them, then
209 doing f.close() in P first closed P's C-level file handle on f, but Q's
210 C-level file handle on f remained open, so the attempt in P to delete f
211 blew up with a "Permission denied" error (Windows doesn't allow
212 deleting open files). This was surprising, subtle, and difficult to
213 work around.
214
215- The os module now exports all the symbolic constants usable with the
216 low-level os.open() on Windows: the new constants in 2.3 are
217 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
218 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
219 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
220 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
221 (so specify both if you want both; note that neither is useful unless
222 specified with O_CREAT too).
223
Tim Petersaf8446f2001-12-21 21:36:50 +0000224Mac
225
226
Tim Peters909c0912001-12-14 23:16:18 +0000227What's New in Python 2.2 final?
228Release date: 21-Dec-2001
229===============================
230
231Type/class unification and new-style classes
232
Barry Warsaw52acb492001-12-21 20:04:22 +0000233- pickle.py, cPickle: allow pickling instances of new-style classes
234 with a custom metaclass.
235
Tim Peters909c0912001-12-14 23:16:18 +0000236Core and builtins
237
Barry Warsaw52acb492001-12-21 20:04:22 +0000238- weakref proxy object: when comparing, unwrap both arguments if both
239 are proxies.
240
Tim Peters909c0912001-12-14 23:16:18 +0000241Extension modules
242
Barry Warsaw52acb492001-12-21 20:04:22 +0000243- binascii.b2a_base64(): fix a potential buffer overrun when encoding
244 very short strings.
245
246- cPickle: the obscure "fast" mode was suspected of causing stack
247 overflows on the Mac. Hopefully fixed this by setting the recursion
248 limit much smaller. If the limit is too low (it only affects
249 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
250 when compiling cPickle.c (or in pyconfig.h).
251
Tim Peters909c0912001-12-14 23:16:18 +0000252Library
253
Barry Warsaw52acb492001-12-21 20:04:22 +0000254- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
255 close or delete time).
256
257- rfc822.py: fixed a bug where the address '<>' was converted to None
258 instead of an empty string (also fixes the email.Utils module).
259
260- xmlrpclib.py: version 1.0.0; uses precision for doubles.
261
262- test suite: the pickle and cPickle tests were not executing any code
263 when run from the standard regresssion test.
264
Tim Peters909c0912001-12-14 23:16:18 +0000265Tools/Demos
266
267Build
268
269C API
270
271New platforms
272
273Tests
274
275Windows
276
Barry Warsaw52acb492001-12-21 20:04:22 +0000277- distutils package: fixed broken Windows installers (bdist_wininst).
278
279- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
280 instances are deleted at process exit time.
281
282- socket.py: prevent mysterious warnings when socket instances are
283 deleted at process exit time.
284
285- posixmodule.c: fix a Windows crash with stat() of a filename ending
286 in backslash.
287
Tim Peters909c0912001-12-14 23:16:18 +0000288Mac
289
Barry Warsaw52acb492001-12-21 20:04:22 +0000290- The Carbon toolbox modules have been upgraded to Universal Headers
291 3.4, and experimental CoreGraphics and CarbonEvents modules have
292 been added. All only for framework-enabled MacOSX.
293
Tim Peters909c0912001-12-14 23:16:18 +0000294
Tim Peters6272dfd2001-12-13 19:34:00 +0000295What's New in Python 2.2c1?
296Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000297===========================
298
299Type/class unification and new-style classes
300
Barry Warsaw06557452001-12-14 20:47:12 +0000301- Guido's tutorial introduction to the new type/class features has
302 been extensively updated. See
303
304 http://www.python.org/2.2/descrintro.html
305
306 That remains the primary documentation in this area.
307
Guido van Rossum33bab012001-12-05 22:45:48 +0000308- Fixed a leak: instance variables declared with __slots__ were never
309 deleted!
310
Guido van Rossum4b800852001-12-03 00:54:52 +0000311- The "delete attribute" method of descriptor objects is called
312 __delete__, not __del__. In previous releases, it was mistakenly
313 called __del__, which created an unfortunate overloading condition
314 with finalizers. (The "get attribute" and "set attribute" methods
315 are still called __get__ and __set__, respectively.)
316
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000317- Some subtle issues with the super built-in were fixed:
318
319 (a) When super itself is subclassed, its __get__ method would still
320 return an instance of the base class (i.e., of super).
321
322 (b) super(C, C()).__class__ would return C rather than super. This
323 is confusing. To fix this, I decided to change the semantics of
324 super so that it only applies to code attributes, not to data
325 attributes. After all, overriding data attributes is not
326 supported anyway.
327
328 (c) The __get__ method didn't check whether the argument was an
329 instance of the type used in creation of the super instance.
330
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000331- Previously, hash() of an instance of a subclass of a mutable type
332 (list or dictionary) would return some value, rather than raising
333 TypeError. This has been fixed. Also, directly calling
334 dict.__hash__ and list.__hash__ now raises the same TypeError
335 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000336
Guido van Rossumd331cb52001-12-05 19:46:42 +0000337- New-style objects now support deleting their __dict__. This is for
338 all intents and purposes equivalent to assigning a brand new empty
339 dictionary, but saves space if the object is not used further.
340
Tim Petersb3c9af12001-11-17 00:21:57 +0000341Core and builtins
342
Tim Peters3caca232001-12-06 06:23:26 +0000343- -Qnew now works as documented in PEP 238: when -Qnew is passed on
344 the command line, all occurrences of "/" use true division instead
345 of classic division. See the PEP for details. Note that "all"
346 means all instances in library and 3rd-party modules, as well as in
347 your own code. As the PEP says, -Qnew is intended for use only in
348 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000349 Note that test_coercion.py in the standard Python test suite fails
350 under -Qnew; this is expected, and won't be repaired until true
351 division becomes the default (in the meantime, test_coercion is
352 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000353
Fred Drake6c01e252001-12-14 17:08:12 +0000354- complex() now only allows the first argument to be a string
355 argument, and raises TypeError if either the second arg is a string
356 or if the second arg is specified when the first is a string.
357
Tim Petersb3c9af12001-11-17 00:21:57 +0000358Extension modules
359
Martin v. Löwis560da622001-11-24 09:24:51 +0000360- gc.get_referents was renamed to gc.get_referrers.
361
Tim Petersb3c9af12001-11-17 00:21:57 +0000362Library
363
Tim Peters25059d32001-12-07 20:35:43 +0000364- Functions in the os.spawn() family now release the global interpreter
365 lock around calling the platform spawn. They should always have done
366 this, but did not before 2.2c1. Multithreaded programs calling
367 an os.spawn function with P_WAIT will no longer block all Python threads
368 until the spawned program completes. It's possible that some programs
369 relies on blocking, although more likely by accident than by design.
370
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000371- webbrowser defaults to netscape.exe on OS/2 now.
372
Martin v. Löwis652e1912001-11-25 14:50:56 +0000373- Tix.ResizeHandle exposes detach_widget, hide, and show.
374
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000375- The charset alias windows_1252 has been added.
376
Barry Warsaw06557452001-12-14 20:47:12 +0000377- types.StringTypes is a tuple containing the defined string types;
378 usually this will be (str, unicode), but if Python was compiled
379 without Unicode support it will be just (str,).
380
381- The pulldom and minidom modules were synchronized to PyXML.
382
Tim Petersb3c9af12001-11-17 00:21:57 +0000383Tools/Demos
384
Barry Warsaw06557452001-12-14 20:47:12 +0000385- A new script called Tools/scripts/google.py was added, which fires
386 off a search on Google.
387
Tim Petersb3c9af12001-11-17 00:21:57 +0000388Build
389
Barry Warsaw06557452001-12-14 20:47:12 +0000390- Note that release builds of Python should arrange to define the
391 preprocessor symbol NDEBUG on the command line (or equivalent).
392 In the 2.2 pre-release series we tried to define this by magic in
393 Python.h instead, but it proved to cause problems for extension
394 authors. The Unix, Windows and Mac builds now all define NDEBUG in
395 release builds via cmdline (or equivalent) instead. Ports to
396 other platforms should do likewise.
397
Jack Jansen1999ef42001-12-06 21:47:20 +0000398- It is no longer necessary to use --with-suffix when building on a
399 case-insensitive file system (such as Mac OS X HFS+). In the build
400 directory an extension is used, but not in the installed python.
401
Tim Petersb3c9af12001-11-17 00:21:57 +0000402C API
403
Tim Petersf582b822001-12-11 18:51:08 +0000404- New function PyDict_MergeFromSeq2() exposes the builtin dict
405 constructor's logic for updating a dictionary from an iterable object
406 producing key-value pairs.
407
Tim Peterscffed4b2001-11-29 03:26:37 +0000408- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000409 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000410 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
411 dump core in some bad cases. This has been repaired. As a result,
412 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
413 previously went unchallenged.
414
Tim Petersb3c9af12001-11-17 00:21:57 +0000415New platforms
416
417Tests
418
419Windows
420
421Mac
422
Jack Jansenffa260f2001-12-06 21:14:00 +0000423- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
424 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000425
Barry Warsaw06557452001-12-14 20:47:12 +0000426- Changed logic for finding python home in Mac OS X framework Pythons.
427 Now sys.executable points to the executable again, in stead of to
428 the shared library. The latter is used only for locating the python
429 home.
430
431
Tim Peters84362bc2001-10-19 17:55:30 +0000432What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000433Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000434===========================
435
436Type/class unification and new-style classes
437
Guido van Rossum3d27df02001-11-15 20:27:54 +0000438- Multiple inheritance mixing new-style and classic classes in the
439 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000440
441 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000442 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000443
444 The MRO (method resolution order) for each base class is respected
445 according to its kind, but the MRO for the derived class is computed
446 using new-style MRO rules if any base clase is a new-style class.
447 This needs to be documented.
448
Tim Petersa427a2b2001-10-29 22:25:45 +0000449- The new builtin dictionary() constructor, and dictionary type, have
450 been renamed to dict. This reflects a decade of common usage.
451
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000452- dict() now accepts an iterable object producing 2-sequences. For
453 example, dict(d.items()) == d for any dictionary d. The argument,
454 and the elements of the argument, can be any iterable objects.
455
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000456- New-style classes can now have a __del__ method, which is called
457 when the instance is deleted (just like for classic classes).
458
Guido van Rossum12d955c2001-10-26 14:56:06 +0000459- Assignment to object.__dict__ is now possible, for objects that are
460 instances of new-style classes that have a __dict__ (unless the base
461 class forbids it).
462
Guido van Rossumc8e56452001-10-22 00:43:43 +0000463- Methods of built-in types now properly check for keyword arguments
464 (formerly these were silently ignored). The only built-in methods
465 that take keyword arguments are __call__, __init__ and __new__.
466
Guido van Rossum86443212001-10-27 22:28:54 +0000467- The socket function has been converted to a type; see below.
468
Tim Peters84362bc2001-10-19 17:55:30 +0000469Core and builtins
470
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000471- Assignment to __debug__ raises SyntaxError at compile-time. This
472 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000473 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000474
Guido van Rossum12d955c2001-10-26 14:56:06 +0000475- Clarified the error messages for unsupported operands to an operator
476 (like 1 + '').
477
Tim Peters84362bc2001-10-19 17:55:30 +0000478Extension modules
479
Tim Peters5ebfd362001-11-13 23:11:19 +0000480- mmap has a new keyword argument, "access", allowing a uniform way for
481 both Windows and Unix users to create read-only, write-through and
482 copy-on-write memory mappings. This was previously possible only on
483 Unix. A new keyword argument was required to support this in a
484 uniform way because the mmap() signuatures had diverged across
485 platforms. Thanks to Jay T Miller for repairing this!
486
Tim Peters169ded02001-11-03 19:57:21 +0000487- By default, the gc.garbage list now contains only those instances in
488 unreachable cycles that have __del__ methods; in 2.1 it contained all
489 instances in unreachable cycles. "Instances" here has been generalized
490 to include instances of both new-style and old-style classes.
491
Guido van Rossum12d955c2001-10-26 14:56:06 +0000492- The socket module defines a new method for socket objects,
493 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000494 send() until all data has been sent. Also, the socket function has
495 been converted to a subclassable type, like list and tuple (etc.)
496 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000497
498- Various bugfixes to the curses module. There is now a test suite
499 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000500
Guido van Rossum692adf12001-10-30 03:03:03 +0000501- binascii.b2a_base64 no longer places an arbitrary restriction of 57
502 bytes on its input.
503
Tim Peters84362bc2001-10-19 17:55:30 +0000504Library
505
Tim Peters5ebfd362001-11-13 23:11:19 +0000506- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000507 convenience function.
508
Tim Peters75335872001-11-03 19:35:43 +0000509- Symbolic group names in regular expressions must be unique. For
510 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
511 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000512 Python 2.2 detects this error at regexp compilation time;
513 previously, the error went undetected, and results were
514 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
515 pattern.subn() methods have been rewritten in C. Also, an
516 experimental function/method finditer() has been added, which works
517 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000518
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000519- Tix exposes more commands through the classes DirSelectBox,
520 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
521 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
522 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
523
Tim Peters98791af2001-10-23 01:59:54 +0000524- Traceback objects are now scanned by cyclic garbage collection, so
525 cycles created by casual use of sys.exc_info() no longer cause
526 permanent memory leaks (provided garbage collection is enabled).
527
Guido van Rossum49192142001-10-24 20:51:44 +0000528- os.extsep -- a new variable needed by the RISCOS support. It is the
529 separator used by extensions, and is '.' on all platforms except
530 RISCOS, where it is '/'. There is no need to use this variable
531 unless you have a masochistic desire to port your code to RISCOS.
532
Barry Warsaw012852b2001-11-16 16:17:27 +0000533- mimetypes.py has optional support for non-standard, but commonly
534 found types. guess_type() and guess_extension() now accept an
535 optional `strict' flag, defaulting to true, which controls whether
536 recognize non-standard types or not. A few non-standard types we
537 know about have been added. Also, when run as a script, there are
538 new -l and -e options.
539
540- statcache is now deprecated.
541
542- email.Utils.formatdate() now produces the preferred RFC 2822 style
543 dates with numeric timezones (it used to produce obsolete dates
544 hard coded to "GMT" timezone). An optional `localtime' flag is
545 added to produce dates in the local timezone, with daylight savings
546 time properly taken into account.
547
548- In pickle and cPickle, instead of masking errors in load() by
549 transforming them into SystemError, we let the original exception
550 propagate out. Also, implement support for __safe_for_unpickling__
551 in pickle, as it already was supported in cPickle.
552
Tim Peters84362bc2001-10-19 17:55:30 +0000553Tools/Demos
554
555Build
556
Barry Warsaw012852b2001-11-16 16:17:27 +0000557- The dbm module is built using libdb1 if available. The bsddb module
558 is built with libdb3 if available.
559
560- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
561
Tim Peters84362bc2001-10-19 17:55:30 +0000562C API
563
Tim Peters1fc240e2001-10-26 05:06:50 +0000564- New function PySequence_Fast_GET_SIZE() returns the size of a non-
565 NULL result from PySequence_Fast(), more quickly than calling
566 PySequence_Size().
567
Barry Warsaw012852b2001-11-16 16:17:27 +0000568- New argument unpacking function PyArg_UnpackTuple() added.
569
570- New functions PyObject_CallFunctionObjArgs() and
571 PyObject_CallMethodObjArgs() have been added to make it more
572 convenient and efficient to call functions and methods from C.
573
574- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
575 possible that this will propagate errors it didn't before.
576
577- New function PyObject_CheckReadBuffer(), which returns true if its
578 argument supports the single-segment readable buffer interface.
579
Tim Peters84362bc2001-10-19 17:55:30 +0000580New platforms
581
Guido van Rossum86443212001-10-27 22:28:54 +0000582- We've finally confirmed that this release builds on HP-UX 11.00,
583 *with* threads, and passes the test suite.
584
Tim Peters7a33d8b2001-11-05 02:51:07 +0000585- Thanks to a series of patches from Michael Muller, Python may build
586 again under OS/2 Visual Age C++.
587
Guido van Rossum49192142001-10-24 20:51:44 +0000588- Updated RISCOS port by Dietmar Schwertberger.
589
Tim Peters84362bc2001-10-19 17:55:30 +0000590Tests
591
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000592- Added a test script for the curses module. It isn't run automatically;
593 regrtest.py must be run with '-u curses' to enable it.
594
Tim Peters84362bc2001-10-19 17:55:30 +0000595Windows
596
Barry Warsaw012852b2001-11-16 16:17:27 +0000597Mac
598
599- PythonScript has been moved to unsupported and is slated to be
600 removed completely in the next release.
601
602- It should now be possible to build applets that work on both OS9 and
603 OSX.
604
605- The core is now linked with CoreServices not Carbon; as a side
606 result, default 8bit encoding on OSX is now ASCII.
607
608- Python should now build on OSX 10.1.1
609
Tim Peters84362bc2001-10-19 17:55:30 +0000610
Tim Petersabf925f2001-09-28 21:53:42 +0000611What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000612Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000613===========================
614
615Type/class unification and new-style classes
616
Guido van Rossum687ae002001-10-15 22:03:32 +0000617- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000618 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000619 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000620 remains: the __dict__ of a new-style class is a read-only proxy; you
621 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000622 __defined__ attribute of new-style types no longer exists, for lack
623 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000624 future a __cache__ may be resurrected with a similar function, if I
625 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000626
Tim Peters1c9ca872001-10-04 06:43:12 +0000627- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
628 always returned None, even when there was a class docstring).
629
630- doctest now finds and runs docstrings attached to new-style classes,
631 class methods, static methods, and properties.
632
Guido van Rossum9074ef62001-10-16 21:34:49 +0000633Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000634
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000635- A very subtle syntactical pitfall in list comprehensions was fixed.
636 For example: [a+b for a in 'abc', for b in 'def']. The comma in
637 this example is a mistake. Previously, this would silently let 'a'
638 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
639 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
640 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
641 Note that [a for a in <singleton>] is a convoluted way to say
642 [<singleton>] anyway, so it's not like any expressiveness is lost.
643
Guido van Rossum9074ef62001-10-16 21:34:49 +0000644- getattr(obj, name, default) now only catches AttributeError, as
645 documented, rather than returning the default value for all
646 exceptions (which could mask bugs in a __getattr__ hook, for
647 example).
648
Fred Drakecb7a6b52001-10-22 18:41:51 +0000649- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000650 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000651 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000652 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000653
Guido van Rossum1c486092001-10-19 02:05:35 +0000654- unicode(obj) now behaves more like str(obj), accepting arbitrary
655 objects, and calling a __unicode__ method if it exists.
656 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000657 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000658
Barry Warsawf6fb1712001-10-19 05:35:40 +0000659- isinstance() now allows any object as the first argument and a
660 class, a type or something with a __bases__ tuple attribute for the
661 second argument. The second argument may also be a tuple of a
662 class, type, or something with __bases__, in which case isinstance()
663 will return true if the first argument is an instance of any of the
664 things contained in the second argument tuple. E.g.
665
666 isinstance(x, (A, B))
667
668 returns true if x is an instance of A or B.
669
Guido van Rossum9074ef62001-10-16 21:34:49 +0000670Extension modules
671
672- thread.start_new_thread() now returns the thread ID (previously None).
673
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000674- binascii has now two quopri support functions, a2b_qp and b2a_qp.
675
Guido van Rossumc524d952001-10-19 01:31:59 +0000676- readline now supports setting the startup_hook and the
677 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000678
Guido van Rossumc524d952001-10-19 01:31:59 +0000679- os and posix supports chroot(), setgroups() and unsetenv() where
680 available. The stat(), fstat(), statvfs() and fstatvfs() functions
681 now return "pseudo-sequences" -- the various fields can now be
682 accessed as attributes (e.g. os.stat("/").st_mtime) but for
683 backwards compatibility they also behave as a fixed-length sequence.
684 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000685 attributes.
686
687- time: localtime(), gmtime() and strptime() now return a
688 pseudo-sequence similar to the os.stat() return value, with
689 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000690
Guido van Rossum9074ef62001-10-16 21:34:49 +0000691- Decompression objects in the zlib module now accept an optional
692 second parameter to decompress() that specifies the maximum amount
693 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000694
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000695- optional SSL support in the socket module now exports OpenSSL
696 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
697 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000698 automatically seed its PRNG. Also, the keyfile and certfile
699 arguments to socket.ssl() are now optional.
700
701- posixmodule (and by extension, the os module on POSIX platforms) now
702 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000703
Guido van Rossum9074ef62001-10-16 21:34:49 +0000704Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000705
Tim Peters7402f792001-10-02 03:53:41 +0000706- doctest now excludes functions and classes not defined by the module
707 being tested, thanks to Tim Hochberg.
708
Fred Drakecb7a6b52001-10-22 18:41:51 +0000709- HotShot, a new profiler implemented using a C-based callback, has
710 been added. This substantially reduces the overhead of profiling,
711 but it is still quite preliminary. Support modules and
712 documentation will be added in upcoming releases (before 2.2 final).
713
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000714- profile now produces correct output in situations where an exception
715 raised in Python is cleared by C code (e.g. hasattr()). This used
716 to cause wrong output, including spurious claims of recursive
717 functions and attribution of time spent to the wrong function.
718
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000719 The code and documentation for the derived OldProfile and HotProfile
720 profiling classes was removed. The code hasn't worked for years (if
721 you tried to use them, they raised exceptions). OldProfile
722 intended to reproduce the behavior of the profiler Python used more
723 than 7 years ago, and isn't interesting anymore. HotProfile intended
724 to provide a faster profiler (but producing less information), and
725 that's a worthy goal we intend to meet via a different approach (but
726 without losing information).
727
Tim Peterscce092d2001-10-09 05:31:56 +0000728- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000729 a much better system-specific calibration constant. The constant can
730 now be specified in an instance constructor, or as a Profile class or
731 instance variable, instead of by editing profile.py's source code.
732 Calibration must still be done manually (see the docs for the profile
733 module).
734
735 Note that Profile.calibrate() must be overriden by subclasses.
736 Improving the accuracy required exploiting detailed knowledge of
737 profiler internals; the earlier method abstracted away the details
738 and measured a simplified model instead, but consequently computed
739 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000740
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000741- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000742 which indicates whether output is intended for the header 'Q'
743 encoding.
744
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000745- The SocketServer.ThreadingMixIn class now closes the request after
746 finish_request() returns. (Not when it errors out though.)
747
Barry Warsawf6fb1712001-10-19 05:35:40 +0000748- The nntplib module's NNTP.body() method has grown a `file' argument
749 to allow saving the message body to a file.
750
751- The email package has added a class email.Parser.HeaderParser which
752 only parses headers and does not recurse into the message's body.
753 Also, the module/class MIMEAudio has been added for representing
754 audio data (contributed by Anthony Baxter).
755
756- ftplib should be able to handle files > 2GB.
757
758- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
759 ON, and OFF.
760
Fred Drakecb7a6b52001-10-22 18:41:51 +0000761- xml.dom.minidom NodeList objects now support the length attribute
762 and item() method as required by the DOM specifications.
763
Guido van Rossumed554f62001-10-02 23:15:37 +0000764Tools/Demos
765
766- Demo/dns was removed. It no longer serves any purpose; a package
767 derived from it is now maintained by Anthony Baxter, see
768 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000769
Barry Warsawf6fb1712001-10-19 05:35:40 +0000770- The freeze tool has been made more robust, and two new options have
771 been added: -X and -E.
772
Tim Petersabf925f2001-09-28 21:53:42 +0000773Build
774
Barry Warsawf6fb1712001-10-19 05:35:40 +0000775- configure will use CXX in LINKCC if CXX is used to build main() and
776 the system requires to link a C++ main using the C++ compiler.
777
Tim Petersabf925f2001-09-28 21:53:42 +0000778C API
779
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000780- The documentation for the tp_compare slot is updated to require that
781 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
782 not correct. This is not yet enforced but will be enforced in
783 Python 2.3; even later, we may use -2 to indicate errors and +2 for
784 "NotImplemented". Right now, -1 should be used for an error return.
785
Tim Petersd38b1c72001-09-30 05:09:37 +0000786- PyLong_AsLongLong() now accepts int (as well as long) arguments.
787 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
788 as long) arguments.
789
Guido van Rossum3c288632001-10-16 21:13:49 +0000790- PyThread_start_new_thread() now returns a long int giving the thread
791 ID, if one can be calculated; it returns -1 for error, 0 if no
792 thread ID is calculated (this is an incompatible change, but only
793 the thread module used this API). This code has only really been
794 tested on Linux and Windows; other platforms please beware (and
795 report any bugs or strange behavior).
796
Guido van Rossum1c486092001-10-19 02:05:35 +0000797- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
798 input.
799
Tim Petersabf925f2001-09-28 21:53:42 +0000800New platforms
801
802Tests
803
804Windows
805
Tim Peters04cf1d32001-10-09 22:39:40 +0000806- Installer: If you install IDLE, and don't disable file-extension
807 registration, a new "Edit with IDLE" context (right-click) menu entry
808 is created for .py and .pyw files.
809
Tim Peters1ce3cf72001-10-01 17:58:40 +0000810- The signal module now supports SIGBREAK on Windows, thanks to Steven
811 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
812 action remains to call Win32 ExitProcess(). This can be changed via
813 signal.signal(). For example:
814
815 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
816 # (SIGINT) behavior.
817 import signal
818 signal.signal(signal.SIGBREAK,
819 signal.default_int_handler)
820
821 try:
822 while 1:
823 pass
824 except KeyboardInterrupt:
825 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
826 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
827 # program without the possibility for any Python-level cleanup).
828 print "Clean exit"
829
Tim Petersabf925f2001-09-28 21:53:42 +0000830
Tim Petersb07352e2001-09-08 01:25:47 +0000831What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000832Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000833===========================
834
Guido van Rossum808eea72001-09-25 04:15:41 +0000835Type/class unification and new-style classes
836
837- pydoc and inspect are now aware of new-style classes;
838 e.g. help(list) at the interactive prompt now shows proper
839 documentation for all operations on list objects.
840
841- Applications using Jim Fulton's ExtensionClass module can now safely
842 be used with Python 2.2. In particular, Zope 2.4.1 now works with
843 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
844 examples also work again. It is hoped that Gtk and Boost also work
845 with 2.2a4 and beyond. (If you can confirm this, please write
846 webmaster@python.org; if there are still problems, please open a bug
847 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000848
Tim Peters66c1a522001-09-24 21:17:50 +0000849- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
850 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
851 in the constructed property object. fget, fset and fdel weren't
852 discoverable from Python in 2.2a3. __doc__ is new, and allows to
853 associate a docstring with a property.
854
Guido van Rossum808eea72001-09-25 04:15:41 +0000855- Comparison overloading is now more completely implemented. For
856 example, a str subclass instance can properly be compared to a str
857 instance, and it can properly overload comparison. Ditto for most
858 other built-in object types.
859
860- The repr() of new-style classes has changed; instead of <type
861 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
862 *except* for built-in types, which are still rendered as <type
863 'Foo'> (to avoid upsetting existing code that might parse or
864 otherwise rely on repr() of certain type objects).
865
866- The repr() of new-style objects is now always <Foo object at XXX>;
867 previously, it was sometimes <Foo instance at XXX>.
868
869- For new-style classes, what was previously called __getattr__ is now
870 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000871 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000872 one in classic classes is defined which is called only if regular
873 attribute access raises AttributeError; to catch *all* attribute
874 access, you can use __getattribute__ (for new-style classes). If
875 both are defined, __getattribute__ is called first, and if it raises
876 AttributeError, __getattr__ is called.
877
878- The __class__ attribute of new-style objects can be assigned to.
879 The new class must have the same C-level object layout as the old
880 class.
881
882- The builtin file type can be subclassed now. In the usual pattern,
883 "file" is the name of the builtin type, and file() is a new builtin
884 constructor, with the same signature as the builtin open() function.
885 file() is now the preferred way to open a file.
886
887- Previously, __new__ would only see sequential arguments passed to
888 the type in a constructor call; __init__ would see both sequential
889 and keyword arguments. This made no sense whatsoever any more, so
890 now both __new__ and __init__ see all arguments.
891
892- Previously, hash() applied to an instance of a subclass of str or
893 unicode always returned 0. This has been repaired.
894
895- Previously, an operation on an instance of a subclass of an
896 immutable type (int, long, float, complex, tuple, str, unicode),
897 where the subtype didn't override the operation (and so the
898 operation was handled by the builtin type), could return that
899 instance instead a value of the base type. For example, if s was of
900 a str sublass type, s[:] returned s as-is. Now it returns a str
901 with the same value as s.
902
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000903- Provisional support for pickling new-style objects has been added.
904
Guido van Rossum808eea72001-09-25 04:15:41 +0000905Core
906
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000907- file.writelines() now accepts any iterable object producing strings.
908
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000909- PyUnicode_FromEncodedObject() now works very much like
910 PyObject_Str(obj) in that it tries to use __str__/tp_str
911 on the object if the object is not a string or buffer. This
912 makes unicode() behave like str() when applied to non-string/buffer
913 objects.
914
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000915- PyFile_WriteObject now passes Unicode objects to the file's write
916 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000917 of a print statement must support Unicode objects, i.e. they must
918 at least convert them into ASCII strings.
919
Guido van Rossum624c8af2001-09-18 15:21:04 +0000920- Thread scheduling on Solaris should be improved; it is no longer
921 necessary to insert a small sleep at the start of a thread in order
922 to let other runnable threads be scheduled.
923
Tim Petersb07352e2001-09-08 01:25:47 +0000924Library
925
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000926- StringIO.StringIO instances and cStringIO.StringIO instances support
927 read character buffer compatible objects for their .write() methods.
928 These objects are converted to strings and then handled as such
929 by the instances.
930
Barry Warsaw2f600732001-09-24 04:28:10 +0000931- The "email" package has been added. This is basically a port of the
932 mimelib package <http://sf.net/projects/mimelib> with API changes
933 and some implementations updated to use iterators and generators.
934
Tim Peters8a9c2842001-09-22 21:30:22 +0000935- difflib.ndiff() and difflib.Differ.compare() are generators now. This
936 restores the ability of Tools/scripts/ndiff.py to start producing output
937 before the entire comparison is complete.
938
Barry Warsaw58b072d2001-09-22 04:44:21 +0000939- StringIO.StringIO instances and cStringIO.StringIO instances support
940 iteration just like file objects (i.e. their .readline() method is
941 called for each iteration until it returns an empty string).
942
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000943- The codecs module has grown four new helper APIs to access
944 builtin codecs: getencoder(), getdecoder(), getreader(),
945 getwriter().
946
Guido van Rossum624c8af2001-09-18 15:21:04 +0000947- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
948 simplifies writing XML RPC servers.
949
Barry Warsaw647d5e82001-09-28 17:01:02 +0000950- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000951 after interpretation of symbolic links. On non-Unix systems, this
952 is an alias for os.path.abspath().
953
Tim Peters16a77ad2001-09-08 04:00:12 +0000954- operator.indexOf() (PySequence_Index() in the C API) now works with any
955 iterable object.
956
Guido van Rossum624c8af2001-09-18 15:21:04 +0000957- smtplib now supports various authentication and security features of
958 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000959
Guido van Rossum624c8af2001-09-18 15:21:04 +0000960- hmac: a new module implementing keyed hashing for message
961 authentication.
962
963- mimetypes now recognizes more extensions and file types. At the
964 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000965
Guido van Rossum624c8af2001-09-18 15:21:04 +0000966- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000967 Python 2.2 bytecode generation. It has also been promoted from a
968 Tool to a standard library package. (Tools/compiler still exists as
969 a sample driver.)
970
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000971Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000972
Tim Petersb07352e2001-09-08 01:25:47 +0000973Build
974
Guido van Rossum624c8af2001-09-18 15:21:04 +0000975- Large file support (LFS) is now automatic when the platform supports
976 it; no more manual configuration tweaks are needed. On Linux, at
977 least, it's possible to have a system whose C library supports large
978 files but whose kernel doesn't; in this case, large file support is
979 still enabled but doesn't do you any good unless you upgrade your
980 kernel or share your Python executable with another system whose
981 kernel has large file support.
982
983- The configure script now supplies plausible defaults in a
984 cross-compilation environment. This doesn't mean that the supplied
985 values are always correct, or that cross-compilation now works
986 flawlessly -- but it's a first step (and it shuts up most of
987 autoconf's warnings about AC_TRY_RUN).
988
989- The Unix build is now a bit less chatty, courtesy of the parser
990 generator. The build is completely silent (except for errors) when
991 using "make -s", thanks to a -q option to setup.py.
992
Tim Petersb07352e2001-09-08 01:25:47 +0000993C API
994
Guido van Rossum624c8af2001-09-18 15:21:04 +0000995- The "structmember" API now supports some new flag bits to deny read
996 and/or write access to attributes in restricted execution mode.
997
Tim Petersb07352e2001-09-08 01:25:47 +0000998New platforms
999
Guido van Rossum624c8af2001-09-18 15:21:04 +00001000- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1001 (http://familiar.handhelds.org).
1002
Tim Petersb07352e2001-09-08 01:25:47 +00001003Tests
1004
Tim Peters8a9c2842001-09-22 21:30:22 +00001005- The "classic" standard tests, which work by comparing stdout to
1006 an expected-output file under Lib/test/output/, no longer stop at
1007 the first mismatch. Instead the test is run to completion, and a
1008 variant of ndiff-style comparison is used to report all differences.
1009 This is much easier to understand than the previous style of reporting.
1010
1011- The unittest-based standard tests now use regrtest's test_main()
1012 convention, instead of running as a side-effect of merely being
1013 imported. This allows these tests to be run in more natural and
1014 flexible ways as unittests, outside the regrtest framework.
1015
1016- regrtest.py is much better integrated with unittest and doctest now,
1017 especially in regard to reporting errors.
1018
Tim Petersb07352e2001-09-08 01:25:47 +00001019Windows
1020
Guido van Rossum624c8af2001-09-18 15:21:04 +00001021- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001022 that support it (NTFS under Windows 2000). See "What's New in
1023 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001024
Tim Petersb07352e2001-09-08 01:25:47 +00001025
Tim Petersedc99312001-08-22 21:36:50 +00001026What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001027Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001028===========================
1029
1030Core
1031
Tim Peters9fffa3e2001-09-04 05:14:19 +00001032- Conversion of long to float now raises OverflowError if the long is too
1033 big to represent as a C double.
1034
Tim Peters32f453e2001-09-03 08:35:41 +00001035- The 3-argument builtin pow() no longer allows a third non-None argument
1036 if either of the first two arguments is a float, or if both are of
1037 integer types and the second argument is negative (in which latter case
1038 the arguments are converted to float, so this is really the same
1039 restriction).
1040
Tim Peters5d2b77c2001-09-03 05:47:38 +00001041- The builtin dir() now returns more information, and sometimes much
1042 more, generally naming all attributes of an object, and all attributes
1043 reachable from the object via its class, and from its class's base
1044 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1045 an empty list. In 2.2a3,
1046
1047 >>> dir([])
1048 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1049 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1050 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1051 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1052 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1053 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1054 'reverse', 'sort']
1055
1056 dir(module) continues to return only the module's attributes, though.
1057
Tim Petersbdee63f2001-09-02 03:40:59 +00001058- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001059 than raising OverflowError. This is a partial implementation of PEP
1060 237. You can use -Wdefault::OverflowWarning to enable a warning for
1061 this situation, and -Werror::OverflowWarning to revert to the old
1062 OverflowError exception.
1063
Guido van Rossum61c345f2001-09-04 03:26:15 +00001064- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001065 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001066 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1067 -Qold, meaning the / operator has its classic meaning and no
1068 warnings are issued. Using -Qwarn issues a run-time warning about
1069 all uses of classic division for int and long arguments; -Qwarnall
1070 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001071 (for use with fixdiv.py).
1072 [Note: the remainder of this paragraph (preserved below) became
1073 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1074 <obsolete>
1075 Using -Qnew is questionable; it turns on new division by default, but
1076 only in the __main__ module. You can usefully combine -Qwarn or
1077 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1078 warns about classic division everywhere else.
1079 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001080
Tim Petersbdee63f2001-09-02 03:40:59 +00001081- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001082 long, float, str, unicode, and tuple. (The types complex, list and
1083 dictionary can also be subclassed; this was introduced earlier.)
1084 Note that restrictions apply when subclassing immutable built-in
1085 types: you can only affect the value of the instance by overloading
1086 __new__. You can add mutable attributes, and the subclass instances
1087 will have a __dict__ attribute, but you cannot change the "value"
1088 (as implemented by the base class) of an immutable subclass instance
1089 once it is created.
1090
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001091- The dictionary constructor now takes an optional argument, a
1092 mapping-like object, and initializes the dictionary from its
1093 (key, value) pairs.
1094
Tim Petersbdee63f2001-09-02 03:40:59 +00001095- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001096 "cooperative super calls" in a multiple inheritance setting. For an
1097 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1098
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001099- A new built-in type, property, has been added. This enables the
1100 creation of "properties". These are attributes implemented by
1101 getter and setter functions (or only one of these for read-only or
1102 write-only attributes), without the need to override __getattr__.
1103 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001104
Tim Petersbdee63f2001-09-02 03:40:59 +00001105- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001106 liberalized, to allow leading zeroes. Examples of literals now
1107 legal that were SyntaxErrors before:
1108
1109 00.0 0e3 0100j 07.5 00000000000000000008.
1110
Tim Petersbdee63f2001-09-02 03:40:59 +00001111- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001112 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1113
Tim Petersedc99312001-08-22 21:36:50 +00001114Library
1115
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001116- telnetlib includes symbolic names for the options, and support for
1117 setting an option negotiation callback.
1118
Tim Petersa40c7932001-09-05 22:36:56 +00001119- The new C standard no longer requires that math libraries set errno to
1120 ERANGE on overflow. For platform libraries that exploit this new
1121 freedom, Python's overflow-checking was wholly broken. A new overflow-
1122 checking scheme attempts to repair that, but may not be reliable on all
1123 platforms (C doesn't seem to provide anything both useful and portable
1124 in this area anymore).
1125
Martin v. Löwis44f86962001-09-05 13:44:54 +00001126- Asynchronous timeout actions are available through the new class
1127 threading.Timer.
1128
Tim Peters78526162001-09-05 00:53:45 +00001129- math.log and math.log10 now return sensible results for even huge
1130 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1131
Tim Petersbdee63f2001-09-02 03:40:59 +00001132- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001133 currently held. See the docs for the imp module.
1134
Tim Petersbdee63f2001-09-02 03:40:59 +00001135- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001136 dumps containing ints written on platforms where Python ints are 8 bytes.
1137 When read on a box where Python ints are 4 bytes, such values are
1138 converted to Python longs.
1139
Tim Petersbdee63f2001-09-02 03:40:59 +00001140- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001141 code objects is no longer allowed. This plugs a security hole.
1142
Steve Purcell6091cd62001-09-06 16:05:17 +00001143- unittest.TestResult instances no longer store references to tracebacks
1144 generated by test failures. This prevents unexpected dangling references
1145 to objects that should be garbage collected between tests.
1146
Tim Petersedc99312001-08-22 21:36:50 +00001147Tools
1148
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001149- Tools/scripts/fixdiv.py has been added which can be used to fix
1150 division operators as per PEP 238.
1151
Tim Petersedc99312001-08-22 21:36:50 +00001152Build
1153
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001154- If you are an adventurous person using Mac OS X you may want to look at
1155 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1156 application, which can be used for experimenting with Carbon or Cocoa.
1157 Discussion of this on pythonmac-sig, please.
1158
Tim Peters7eea37e2001-09-04 22:08:56 +00001159C API
1160
1161- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001162
Tim Peters9fffa3e2001-09-04 05:14:19 +00001163- Note that PyLong_AsDouble can fail! This has always been true, but no
1164 callers checked for it. It's more likely to fail now, because overflow
1165 errors are properly detected now. The proper way to check:
1166
1167 double x = PyLong_AsDouble(some_long_object);
1168 if (x == -1.0 && PyErr_Occurred()) {
1169 /* The conversion failed. */
1170 }
1171
Tim Petersbdee63f2001-09-02 03:40:59 +00001172- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001173 compile but will not participate in GC. To upgrade an extension
1174 module:
1175
1176 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001177
Neil Schemenauer4042c692001-08-30 15:38:01 +00001178 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1179 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001180
Neil Schemenauer4042c692001-08-30 15:38:01 +00001181 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1182 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001183
Neil Schemenauer4042c692001-08-30 15:38:01 +00001184 - remove PyGC_HEAD_SIZE from object size calculations
1185
1186 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1187
Tim Petersbdee63f2001-09-02 03:40:59 +00001188- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001189 These can be used safely to construct string objects from a
1190 sprintf-style format string (similar to the format string supported
1191 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001192
Tim Petersedc99312001-08-22 21:36:50 +00001193New platforms
1194
Tim Petersb7da0902001-09-02 23:01:43 +00001195- Stephen Hansen contributed patches sufficient to get a clean compile
1196 under Borland C (Windows), but he reports problems running it and ran
1197 out of time to complete the port. Volunteers? Expect a MemoryError
1198 when importing the types module; this is probably shallow, and
1199 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001200
Tim Petersedc99312001-08-22 21:36:50 +00001201Tests
1202
1203Windows
1204
Tim Peters6e13a562001-09-06 00:32:15 +00001205- Large file support is now enabled on Win32 platforms as well as on
1206 Win64. This means that, for example, you can use f.tell() and f.seek()
1207 to manipulate files larger than 2 gigabytes (provided you have enough
1208 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001209 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1210 filesize limit, and large file support makes no difference there.
1211 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1212 NTFS has no practical limit on file size, and files of any size can be
1213 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001214
Tim Petersbdee63f2001-09-02 03:40:59 +00001215- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001216 points to command.com (patch from Brian Quinlan).
1217
Tim Petersedc99312001-08-22 21:36:50 +00001218
Tim Peters20f51a72001-07-21 02:31:40 +00001219What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001220Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001221===========================
1222
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001223Build
1224
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001225- Tim Peters developed a brand new Windows installer using Wise 8.1,
1226 generously donated to us by Wise Solutions.
1227
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001228- configure supports a new option --enable-unicode, with the values
1229 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1230 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001231
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001232- A new configure option --enable-framework builds a Mac OS X framework,
1233 which "make frameworkinstall" will install. This provides a starting
1234 point for more mac-like functionality, join pythonmac-sig@python.org
1235 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001236
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001237- The NeXT platform is no longer supported.
1238
1239- The `new' module is now statically linked.
1240
Tim Peters0afb6092001-08-15 06:06:44 +00001241Tools
1242
1243- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001244 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001245 the module docstring for details.
1246
Tim Peters20f51a72001-07-21 02:31:40 +00001247Tests
1248
Tim Peters5e824c32001-08-12 22:25:01 +00001249- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001250 platforms, allowing to give clearer test result output. regrtest
1251 also has optional --use/-u switch to run normally disabled tests
1252 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001253
Tim Peters20f51a72001-07-21 02:31:40 +00001254- Several new tests in the standard test suite, with special thanks to
1255 Nick Mathewson.
1256
1257Core
1258
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001259- The floor division operator // has been added as outlined in PEP
1260 238. The / operator still provides classic division (and will until
1261 Python 3.0) unless "from __future__ import division" is included, in
1262 which case the / operator will provide true division. The operator
1263 module provides truediv() and floordiv() functions. Augmented
1264 assignment variants are included, as are the equivalent overloadable
1265 methods and C API methods. See the PEP for a full discussion:
1266 <http://python.sf.net/peps/pep-0238.html>
1267
Tim Peters6cd6a822001-08-17 22:11:27 +00001268- Future statements are now effective in simulated interactive shells
1269 (like IDLE). This should "just work" by magic, but read Michael
1270 Hudson's "Future statements in simulated shells" PEP 264 for full
1271 details: <http://python.sf.net/peps/pep-0264.html>.
1272
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001273- The type/class unification (PEP 252-253) was integrated into the
1274 trunk and is not so tentative any more (the exact specification of
1275 some features is still tentative). A lot of work has done on fixing
1276 bugs and adding robustness and features (performance still has to
1277 come a long way).
1278
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001279- Warnings about a mismatch in the Python API during extension import
1280 now use the Python warning framework (which makes it possible to
1281 write filters for these warnings).
1282
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001283- A function's __dict__ (aka func_dict) will now always be a
1284 dictionary. It used to be possible to delete it or set it to None,
1285 but now both actions raise TypeErrors. It is still legal to set it
1286 to a dictionary object. Getting func.__dict__ before any attributes
1287 have been assigned now returns an empty dictionary instead of None.
1288
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001289- A new command line option, -E, was added which disables the use of
1290 all environment variables, or at least those that are specifically
1291 significant to Python. Usually those have a name starting with
1292 "PYTHON". This was used to fix a problem where the tests fail if
1293 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1294 older distribution.
1295
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001296Library
1297
Tim Peters5e824c32001-08-12 22:25:01 +00001298- New class Differ and new functions ndiff() and restore() in difflib.py.
1299 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001300 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001301
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001302- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1303 value using the minimal quoting required for the value; more
1304 reliable than using xml.sax.saxutils.escape() for attribute values.
1305
1306- Readline completion support for cmd.Cmd was added.
1307
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001308- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1309
1310- Added function threading.BoundedSemaphore()
1311
1312- Added Ka-Ping Yee's cgitb.py module.
1313
1314- The `new' module now exposes the CO_xxx flags.
1315
Martin v. Löwis560da622001-11-24 09:24:51 +00001316- The gc module offers the get_referents function.
1317
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001318New platforms
1319
1320C API
1321
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001322- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1323 which provide a cross-platform implementations for the
1324 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1325 the standard sprintf() and vsprintf() C lib APIs, these versions
1326 apply bounds checking on the used buffer which enhances protection
1327 against buffer overruns.
1328
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001329- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001330 and extensions using different Unicode widths is rendered next to
1331 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001332 will result in an ImportError. Unicode extensions writers must make
1333 sure to check the Unicode width compatibility in their extensions by
1334 using at least one of the mangled Unicode APIs in the extension.
1335
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001336- Two new flags METH_NOARGS and METH_O are available in method definition
1337 tables to simplify implementation of methods with no arguments and a
1338 single untyped argument. Calling such methods is more efficient than
1339 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1340 deprecated.
1341
Tim Petersc1731372001-08-04 08:12:36 +00001342Windows
1343
1344- "import module" now compiles module.pyw if it exists and nothing else
1345 relevant is found.
1346
Tim Peters20f51a72001-07-21 02:31:40 +00001347
Guido van Rossum55a78992001-07-17 17:22:32 +00001348What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001349Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001350===========================
1351
1352Core
Tim Petersa814db52001-05-14 07:05:58 +00001353
Tim Peters6d6c1a32001-08-02 04:15:00 +00001354- TENTATIVELY, a large amount of code implementing much of what's
1355 described in PEP 252 (Making Types Look More Like Classes) and PEP
1356 253 (Subtyping Built-in Types) was added. This will be released
1357 with Python 2.2a1. Documentation will be provided separately
1358 through http://www.python.org/2.2/. The purpose of releasing this
1359 with Python 2.2a1 is to test backwards compatibility. It is
1360 possible, though not likely, that a decision is made not to release
1361 this code as part of 2.2 final, if any serious backwards
1362 incompapatibilities are found during alpha testing that cannot be
1363 repaired.
1364
Guido van Rossum55a78992001-07-17 17:22:32 +00001365- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001366 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001367 more 'yield' statements. See PEP 255. Since this adds a new
1368 keyword to the language, this feature must be enabled by including a
1369 future statement: "from __future__ import generators" (see PEP 236).
1370 Generators will become a standard feature in a future release
1371 (probably 2.3). Without this future statement, 'yield' remains an
1372 ordinary identifier, but a warning is issued each time it is used.
1373 (These warnings currently don't conform to the warnings framework of
1374 PEP 230; we intend to fix this in 2.2a2.)
1375
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001376- The UTF-16 codec was modified to be more RFC compliant. It will now
1377 only remove BOM characters at the start of the string and then
1378 only if running in native mode (UTF-16-LE and -BE won't remove a
1379 leading BMO character).
1380
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001381- Strings now have a new method .decode() to complement the already
1382 existing .encode() method. These two methods provide direct access
1383 to the corresponding decoders and encoders of the registered codecs.
1384
1385 To enhance the usability of the .encode() method, the special
1386 casing of Unicode object return values was dropped (Unicode objects
1387 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001388
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001389 Both methods will now return whatever the codec in charge of the
1390 requested encoding returns as object, e.g. Unicode codecs will
1391 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1392 will return u"äöü"). This enables codec writer to create codecs
1393 for various simple to use conversions.
1394
1395 New codecs were added to demonstrate these new features (the .encode()
1396 and .decode() columns indicate the type of the returned objects):
1397
1398 Name | .encode() | .decode() | Description
1399 ----------------------------------------------------------------------
1400 uu | string | string | UU codec (e.g. for email)
1401 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001402 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001403 zlib | string | string | zlib compression
1404 hex | string | string | 2-byte hex codec
1405 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1406
Mark Hammond2a0af792001-05-14 03:09:36 +00001407- Some operating systems now support the concept of a default Unicode
1408 encoding for file system operations. Notably, Windows supports 'mbcs'
1409 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001410 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001411 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001412
1413 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001414 functions that return filenames (such as os.listdir()) to return Python
1415 string objects pre-encoded using the default file system encoding for
1416 the platform. As this encoding is likely to be different from Python's
1417 default encoding, converting this name to a Unicode object before passing
1418 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001419 would attempt to use its default encoding (generally ASCII) rather than
1420 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001421
Tim Petersa814db52001-05-14 07:05:58 +00001422 In general, this change simply removes surprises when working with
1423 Unicode and the file system, making these operations work as you expect,
1424 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001425 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001426
Tim Peters61dff2b2001-05-08 15:43:37 +00001427- Float (and complex) literals in source code were evaluated to full
1428 precision only when running from a .py file; the same code loaded from a
1429 .pyc (or .pyo) file could suffer numeric differences starting at about the
1430 12th significant decimal digit. For example, on a machine with IEEE-754
1431 floating arithmetic,
1432
1433 x = 9007199254740992.0
1434 print long(x)
1435
1436 printed 9007199254740992 if run directly from .py, but 9007199254740000
1437 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1438 str(float) instead of repr(float) when building code objects. marshal
1439 now uses repr(float) instead, which should reproduce floats to full
1440 machine precision (assuming the platform C float<->string I/O conversion
1441 functions are of good quality).
1442
1443 This may cause floating-point results to change in some cases, and
1444 usually for the better, but may also cause numerically unstable
1445 algorithms to break.
1446
Tim Peters2f228e72001-05-13 00:19:31 +00001447- The implementation of dicts suffers fewer collisions, which has speed
1448 benefits. However, the order in which dict entries appear in dict.keys(),
1449 dict.values() and dict.items() may differ from previous releases for a
1450 given dict. Nothing is defined about this order, so no program should
1451 rely on it. Nevertheless, it's easy to write test cases that rely on the
1452 order by accident, typically because of printing the str() or repr() of a
1453 dict to an "expected results" file. See Lib/test/test_support.py's new
1454 sortdict(dict) function for a simple way to display a dict in sorted
1455 order.
1456
Tim Peters7a3bfc32001-06-12 01:22:22 +00001457- Many other small changes to dicts were made, resulting in faster
1458 operation along the most common code paths.
1459
Guido van Rossum10315822001-05-01 20:54:30 +00001460- Dictionary objects now support the "in" operator: "x in dict" means
1461 the same as dict.has_key(x).
1462
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001463- The update() method of dictionaries now accepts generic mapping
1464 objects. Specifically the argument object must support the .keys()
1465 and __getitem__() methods. This allows you to say, for example,
1466 {}.update(UserDict())
1467
Guido van Rossum10315822001-05-01 20:54:30 +00001468- Iterators were added; this is a generalized way of providing values
1469 to a for loop. See PEP 234. There's a new built-in function iter()
1470 to return an iterator. There's a new protocol to get the next value
1471 from an iterator using the next() method (in Python) or the
1472 tp_iternext slot (in C). There's a new protocol to get iterators
1473 using the __iter__() method (in Python) or the tp_iter slot (in C).
1474 Iterating (i.e. a for loop) over a dictionary generates its keys.
1475 Iterating over a file generates its lines.
1476
Tim Petersf553f892001-05-01 20:45:31 +00001477- The following functions were generalized to work nicely with iterator
1478 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001479 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001480 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1481 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001482 join() method of strings
1483 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001484 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1485 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001486 right-hand side of assignment statements with multiple targets, such as
1487 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001488
Tim Petersd85e1022001-05-11 21:51:48 +00001489- Accessing module attributes is significantly faster (for example,
1490 random.random or os.path or yourPythonModule.yourAttribute).
1491
Tim Peterse63415e2001-05-08 04:38:29 +00001492- Comparing dictionary objects via == and != is faster, and now works even
1493 if the keys and values don't support comparisons other than ==.
1494
Tim Peters95bf9392001-05-10 08:32:44 +00001495- Comparing dictionaries in ways other than == and != is slower: there were
1496 insecurities in the dict comparison implementation that could cause Python
1497 to crash if the element comparison routines for the dict keys and/or
1498 values mutated the dicts. Making the code bulletproof slowed it down.
1499
Tim Peterseb28ef22001-06-02 05:27:19 +00001500- Collisions in dicts are resolved via a new approach, which can help
1501 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001502 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001503 faster now. Thanks to Christian Tismer for pointing out the cause and
1504 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001505
Tim Peters52e155e2001-06-16 05:42:57 +00001506- repr() is much faster for large containers (dict, list, tuple).
1507
1508
Tim Petersa814db52001-05-14 07:05:58 +00001509Library
1510
Fred Drake960fdf92001-07-20 18:38:26 +00001511- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1512 were added to the string module. These a locale-indenpendent
1513 constants, unlike letters, lowercase, and uppercase. These are now
1514 use in appropriate locations in the standard library.
1515
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001516- The flags used in dlopen calls can now be configured using
1517 sys.setdlopenflags and queried using sys.getdlopenflags.
1518
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001519- Fredrik Lundh's xmlrpclib is now a standard library module. This
1520 provides full client-side XML-RPC support. In addition,
1521 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1522 one asyncore-based). Thanks to Eric Raymond for the documentation.
1523
Guido van Rossum643d3912001-07-05 14:46:25 +00001524- The xrange() object is simplified: it no longer supports slicing,
1525 repetition, comparisons, efficient 'in' checking, the tolist()
1526 method, or the start, stop and step attributes. See PEP 260.
1527
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001528- A new function fnmatch.filter to filter lists of file names was added.
1529
Barry Warsawffd674d2001-05-22 16:00:10 +00001530- calendar.py uses month and day names based on the current locale.
1531
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001532- strop is now *really* obsolete (this was announced before with 1.6),
1533 and issues DeprecationWarning when used (except for the four items
1534 that are still imported into string.py).
1535
Tim Petersa814db52001-05-14 07:05:58 +00001536- Cookie.py now sorts key+value pairs by key in output strings.
1537
1538- pprint.isrecursive(object) didn't correctly identify recursive objects.
1539 Now it does.
1540
Tim Peters95b3f782001-05-14 18:39:41 +00001541- pprint functions now much faster for large containers (tuple, list, dict).
1542
Tim Peters7b9542a2001-06-10 23:40:19 +00001543- New 'q' and 'Q' format codes in the struct module, corresponding to C
1544 types "long long" and "unsigned long long" (on Windows, __int64). In
1545 native mode, these can be used only when the platform C compiler supports
1546 these types (when HAVE_LONG_LONG is #define'd by the Python config
1547 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001548 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1549 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001550
Guido van Rossum83213cc2001-06-12 16:48:52 +00001551- The site module installs a new built-in function 'help' that invokes
1552 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1553 it displays a message reminding the user to use 'help()' or
1554 'help(object)'.
1555
Tim Petersa814db52001-05-14 07:05:58 +00001556Tests
1557
1558- New test_mutants.py runs dict comparisons where the key and value
1559 comparison operators mutute the dicts randomly during comparison. This
1560 rapidly causes Python to crash under earlier releases (not for the faint
1561 of heart: it can also cause Win9x to freeze or reboot!).
1562
1563- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001564 pprint.isreadable() return sensible results. Also verifies that simple
1565 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001566
Tim Peters4324aa32001-05-28 22:30:08 +00001567C API
1568
1569- Removed the unused last_is_sticky argument from the internal
1570 _PyTuple_Resize(). If this affects you, you were cheating.
1571
1572
Guido van Rossum55a78992001-07-17 17:22:32 +00001573======================================================================
1574
1575
Guido van Rossumffe13be2001-04-16 18:46:45 +00001576What's New in Python 2.1 (final)?
1577=================================
1578
1579We only changed a few things since the last release candidate, all in
1580Python library code:
1581
1582- A bug in the locale module was fixed that affected locales which
1583 define no grouping for numeric formatting.
1584
1585- A few bugs in the weakref module's implementations of weak
1586 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1587 and the test suite was updated to check for these bugs.
1588
1589- An old bug in the os.path.walk() function (introduced in Python
1590 2.0!) was fixed: a non-existent file would cause an exception
1591 instead of being ignored.
1592
1593- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1594 PyChecker.
1595
1596
Guido van Rossum5b08f132001-04-16 02:05:23 +00001597What's New in Python 2.1c2?
1598===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001599
Guido van Rossum5b08f132001-04-16 02:05:23 +00001600A flurry of small changes, and one showstopper fixed in the nick of
1601time made it necessary to release another release candidate. The list
1602here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001603
Guido van Rossum5b08f132001-04-16 02:05:23 +00001604Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001605
Guido van Rossum5b08f132001-04-16 02:05:23 +00001606- Tim discovered a nasty bug in the dictionary code, caused by
1607 PyDict_Next() calling dict_resize(), and the GC code's use of
1608 PyDict_Next() violating an assumption in dict_items(). This was
1609 fixed with considerable amounts of band-aid, but the net effect is a
1610 saner and more robust implementation.
1611
1612- Made a bunch of symbols static that were accidentally global.
1613
1614Build and Ports
1615
1616- The setup.py script didn't check for a new enough version of zlib
1617 (1.1.3 is needed). Now it does.
1618
1619- Changed "make clean" target to also remove shared libraries.
1620
1621- Added a more general warning about the SGI Irix optimizer to README.
1622
1623Library
1624
1625- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1626 omitted the slash between host and file.html.
1627
1628- The mailbox module's _Mailbox class contained a completely broken
1629 and undocumented seek() method. Ripped it out.
1630
1631- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1632 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1633
1634- Fixed a few last-minute bugs in unittest.
1635
1636Extensions
1637
1638- Reverted the patch to the OpenSSL code in socketmodule.c to support
1639 RAND_status() and the EGD, and the subsequent patch that tried to
1640 fix it for pre-0.9.5 versions; the problem with the patch is that on
1641 some systems it issues a warning whenever socket is imported, and
1642 that's unacceptable.
1643
1644Tests
1645
1646- Fixed the pickle tests to work with "import test.test_pickle".
1647
1648- Tweaked test_locale.py to actually run the test Windows.
1649
1650- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1651 not "wb" (which is not a valid mode at all).
1652
1653- Fix pstats browser crashes. Import readline if it exists to make
1654 the user interface nicer.
1655
1656- Add "import thread" to the top of test modules that import the
1657 threading module (test_asynchat and test_threadedtempfile). This
1658 prevents test failures caused by a broken threading module resulting
1659 from a previously caught failed import.
1660
1661- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1662 needed on some platforms (e.g. Solaris 8) when the tests are run
1663 twice in succession.
1664
1665- Skip rather than fail test_sunaudiodev if no audio device is found.
1666
1667
1668What's New in Python 2.1c1?
1669===========================
1670
1671This list was significantly updated when 2.1c2 was released; the 2.1c1
1672release didn't mention most changes that were actually part of 2.1c1:
1673
1674Legal
1675
1676- Copyright was assigned to the Python Software Foundation (PSF) and a
1677 PSF license (very similar to the CNRI license) was added.
1678
1679- The CNRI copyright notice was updated to include 2001.
1680
1681Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001682
Guido van Rossumc9932722001-04-12 02:31:27 +00001683- After a public outcry, assignment to __debug__ is no longer illegal;
1684 instead, a warning is issued. It will become illegal in 2.2.
1685
Guido van Rossum5b08f132001-04-16 02:05:23 +00001686- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1687 "%#x" now always prepends "0x", even if the value is zero.
1688
1689- Fixed some nits in the bytecode compiler.
1690
1691- Fixed core dumps when calling certain kinds of non-functions.
1692
1693- Fixed various core dumps caused by reference count bugs.
1694
1695Build and Ports
1696
1697- Use INSTALL_SCRIPT to install script files.
1698
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001699- New port: SCO Unixware 7, by Billy G. Allie.
1700
Guido van Rossum5b08f132001-04-16 02:05:23 +00001701- Updated RISCOS port.
1702
1703- Updated BeOS port and notes.
1704
1705- Various other porting problems resolved.
1706
1707Library
1708
1709- The TERMIOS and SOCKET modules are now truly obsolete and
1710 unnecessary. Their symbols are incorporated in the termios and
1711 socket modules.
1712
1713- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1714 better tests for pickling.
1715
1716- threading: make Condition.wait() robust against KeyboardInterrupt.
1717
1718- zipfile: add support to zipfile to support opening an archive
1719 represented by an open file rather than a file name. Fix bug where
1720 the archive was not properly closed. Fixed a bug in this bugfix
1721 where flush() was called for a read-only file.
1722
1723- imputil: added an uninstall() method to the ImportManager.
1724
1725- Canvas: fixed bugs in lower() and tkraise() methods.
1726
1727- SocketServer: API change (added overridable close_request() method)
1728 so that the TCP server can explicitly close the request.
1729
1730- pstats: Eric Raymond added a simple interactive statistics browser,
1731 invoked when the module is run as a script.
1732
1733- locale: fixed a problem in format().
1734
1735- webbrowser: made it work when the BROWSER environment variable has a
1736 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1737 KDE 2. Fixed some other nits.
1738
1739- unittest: changes to allow using a different exception than
1740 AssertionError, and added a few more function aliases. Some other
1741 small changes.
1742
1743- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1744
1745- asynchat: fixed a critical bug in asynchat that slipped through the
1746 2.1b2 release. Fixed another rare bug.
1747
1748- Fix some unqualified except: clauses (always a bad code example).
1749
1750XML
1751
1752- pyexpat: new API get_version_string().
1753
1754- Fixed some minidom bugs.
1755
1756Extensions
1757
1758- Fixed a core dump in _weakref. Removed the weakref.mapping()
1759 function (it adds nothing to the API).
1760
1761- Rationalized the use of header files in the readline module, to make
1762 it compile (albeit with some warnings) with the very recent readline
1763 4.2, without breaking for earlier versions.
1764
1765- Hopefully fixed a buffering problem in linuxaudiodev.
1766
1767- Attempted a fix to make the OpenSSL support in the socket module
1768 work again with pre-0.9.5 versions of OpenSSL.
1769
1770Tests
1771
1772- Added a test case for asynchat and asyncore.
1773
1774- Removed coupling between tests where one test failing could break
1775 another.
1776
1777Tools
1778
1779- Ping added an interactive help browser to pydoc, fixed some nits
1780 in the rest of the pydoc code, and added some features to his
1781 inspect module.
1782
1783- An updated python-mode.el version 4.1 which integrates Ken
1784 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1785 much nicer in XEmacs and Emacs. When stepping through your program
1786 with pdb, in either the shell window or the *Python* window, the
1787 source file and line will be tracked by an arrow. Very cool!
1788
1789- IDLE: syntax warnings in interactive mode are changed into errors.
1790
1791- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001792 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001793
1794- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001795
Barry Warsaw11e89c72001-04-11 20:37:57 +00001796
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001797What's New in Python 2.1 beta 2?
1798================================
1799
Guido van Rossum053ae352001-03-22 14:17:21 +00001800(Unlisted are many fixed bugs, more documentation, etc.)
1801
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001802Core language, builtins, and interpreter
1803
Guido van Rossum053ae352001-03-22 14:17:21 +00001804- The nested scopes work (enabled by "from __future__ import
1805 nested_scopes") is completed; in particular, the future now extends
1806 into code executed through exec, eval() and execfile(), and into the
1807 interactive interpreter.
1808
1809- When calling a base class method (e.g. BaseClass.__init__(self)),
1810 this is now allowed even if self is not strictly spoken a class
1811 instance (e.g. when using metaclasses or the Don Beaudry hook).
1812
1813- Slice objects are now comparable but not hashable; this prevents
1814 dict[:] from being accepted but meaningless.
1815
1816- Complex division is now calculated using less braindead algorithms.
1817 This doesn't change semantics except it's more likely to give useful
1818 results in extreme cases. Complex repr() now uses full precision
1819 like float repr().
1820
1821- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1822
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001823- It is illegal to assign to the name __debug__, which is set when the
1824 interpreter starts. It is effectively a compile-time constant.
1825
1826- A warning will be issued if a global statement for a variable
1827 follows a use or assignment of that variable.
1828
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001829Standard library
1830
Guido van Rossum053ae352001-03-22 14:17:21 +00001831- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1832 inspired by JUnit), is now part of the standard library. You now
1833 have a choice of two testing frameworks: unittest requires you to
1834 write testcases as separate code, doctest gathers them from
1835 docstrings. Both approaches have their advantages and
1836 disadvantages.
1837
1838- A new module Tix was added, which wraps the Tix extension library
1839 for Tk. With that module, it is not necessary to statically link
1840 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1841 require" command. See Demo/tix/.
1842
1843- tzparse.py is now obsolete.
1844
1845- In gzip.py, the seek() and tell() methods are removed -- they were
1846 non-functional anyway, and it's better if callers can test for their
1847 existence with hasattr().
1848
1849Python/C API
1850
1851- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1852 that's already in the dictionary during a PyDict_Next() iteration.
1853 This used to fail occasionally when a dictionary resize operation
1854 could be triggered that would rehash all the keys. All other
1855 modifications to the dictionary are still off-limits during a
1856 PyDict_Next() iteration!
1857
1858- New extended APIs related to passing compiler variables around.
1859
1860- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1861 implement isinstance() and issubclass().
1862
1863- Py_BuildValue() now has a "D" conversion to create a Python complex
1864 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001865
Fred Drake4e262a92001-03-22 18:26:47 +00001866- Extensions types which support weak references must now set the
1867 field allocated for the weak reference machinery to NULL themselves;
1868 this is done to avoid the cost of checking each object for having a
1869 weakly referencable type in PyObject_INIT(), since most types are
1870 not weakly referencable.
1871
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001872- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1873 free variables and cell variables to and from the frame's f_locals.
1874
1875- Variants of several functions defined in pythonrun.h have been added
1876 to support the nested_scopes future statement. The variants all end
1877 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1878 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1879 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001880 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001881
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001882Distutils
1883
1884- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1885 into the release tree.
1886
Tim Peters0e57abf2001-05-02 07:39:38 +00001887- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001888 (an uninstaller, more customization of the installer's display)
1889
1890- from Jack Jansen: added Mac-specific code to generate a dialog for
1891 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001892 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001893 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001894
1895- added 'platforms' and 'keywords' to the set of metadata that can be
1896 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001897
1898- applied patches from Jason Tishler to make the compiler class work with
1899 Cygwin.
1900
1901
Tim Peters2fe289a2001-03-01 22:19:38 +00001902What's New in Python 2.1 beta 1?
1903================================
Tim Petersd66595f2001-02-04 03:09:53 +00001904
1905Core language, builtins, and interpreter
1906
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001907- Following an outcry from the community about the amount of code
1908 broken by the nested scopes feature introduced in 2.1a2, we decided
1909 to make this feature optional, and to wait until Python 2.2 (or at
1910 least 6 months) to make it standard. The option can be enabled on a
1911 per-module basis by adding "from __future__ import nested_scopes" at
1912 the beginning of a module (before any other statements, but after
1913 comments and an optional docstring). See PEP 236 (Back to the
1914 __future__) for a description of the __future__ statement. PEP 227
1915 (Statically Nested Scopes) has been updated to reflect this change,
1916 and to clarify the semantics in a number of endcases.
1917
1918- The nested scopes code, when enabled, has been hardened, and most
1919 bugs and memory leaks in it have been fixed.
1920
1921- Compile-time warnings are now generated for a number of conditions
1922 that will break or change in meaning when nested scopes are enabled:
1923
1924 - Using "from...import *" or "exec" without in-clause in a function
1925 scope that also defines a lambda or nested function with one or
1926 more free (non-local) variables. The presence of the import* or
1927 bare exec makes it impossible for the compiler to determine the
1928 exact set of local variables in the outer scope, which makes it
1929 impossible to determine the bindings for free variables in the
1930 inner scope. To avoid the warning about import *, change it into
1931 an import of explicitly name object, or move the import* statement
1932 to the global scope; to avoid the warning about bare exec, use
1933 exec...in... (a good idea anyway -- there's a possibility that
1934 bare exec will be deprecated in the future).
1935
1936 - Use of a global variable in a nested scope with the same name as a
1937 local variable in a surrounding scope. This will change in
1938 meaning with nested scopes: the name in the inner scope will
1939 reference the variable in the outer scope rather than the global
1940 of the same name. To avoid the warning, either rename the outer
1941 variable, or use a global statement in the inner function.
1942
Neil Schemenauera35c6882001-02-27 04:45:05 +00001943- An optional object allocator has been included. This allocator is
1944 optimized for Python objects and should be faster and use less memory
1945 than the standard system allocator. It is not enabled by default
1946 because of possible thread safety problems. The allocator is only
1947 protected by the Python interpreter lock and it is possible that some
1948 extension modules require a thread safe allocator. The object
1949 allocator can be enabled by providing the "--with-pymalloc" option to
1950 configure.
1951
Tim Petersd66595f2001-02-04 03:09:53 +00001952Standard library
1953
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001954- pyexpat now detects the expat version if expat.h defines it. A
1955 number of additional handlers are provided, which are only available
1956 since expat 1.95. In addition, the methods SetParamEntityParsing and
1957 GetInputContext of Parser objects are available with 1.95.x
1958 only. Parser objects now provide the ordered_attributes and
1959 specified_attributes attributes. A new module expat.model was added,
1960 which offers a number of additional constants if 1.95.x is used.
1961
1962- xml.dom offers the new functions registerDOMImplementation and
1963 getDOMImplementation.
1964
1965- xml.dom.minidom offers a toprettyxml method. A number of DOM
1966 conformance issues have been resolved. In particular, Element now
1967 has an hasAttributes method, and the handling of namespaces was
1968 improved.
1969
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001970- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1971 getting information about live Python code, and pydoc.py, a module
1972 for interactively converting docstrings to HTML or text.
1973 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001974 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001975 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1976 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001977
Tim Peters1eff7962001-03-01 02:31:33 +00001978- New library module difflib.py, primarily packaging the SequenceMatcher
1979 class at the heart of the popular ndiff.py file-comparison tool.
1980
1981- doctest.py (a framework for verifying Python code examples in docstrings)
1982 is now part of the std library.
1983
Tim Petersd66595f2001-02-04 03:09:53 +00001984Windows changes
1985
Guido van Rossume3955a82001-03-02 14:05:59 +00001986- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1987 small GUI that lets you browse the module docstrings using your
1988 default web browser.
1989
Tim Peters1eff7962001-03-01 02:31:33 +00001990- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1991 Platforms) is implemented. See
1992
1993 http://python.sourceforge.net/peps/pep-0235.html
1994
1995 for full details, especially the "Current Lower-Left Semantics" section.
1996 The new Windows import rules are simpler than before:
1997
1998 A. If the PYTHONCASEOK environment variable exists, same as
1999 before: silently accept the first case-insensitive match of any
2000 kind; raise ImportError if none found.
2001
2002 B. Else search sys.path for the first case-sensitive match; raise
2003 ImportError if none found.
2004
2005 The same rules have been implented on other platforms with case-
2006 insensitive but case-preserving filesystems too (including Cygwin, and
2007 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002008
Tim Peters25a9ce32001-02-19 07:06:36 +00002009- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2010 what it's supposed to do (and does do under NT and 2000) via direct
2011 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002012 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002013 all Win9x systems before.
2014
Tim Peters1eff7962001-03-01 02:31:33 +00002015- Build: Subproject _test (effectively) renamed to _testcapi.
2016
Tim Peters2fe289a2001-03-01 22:19:38 +00002017New platforms
2018
2019- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2020 Thanks to Steven Majewski!
2021
2022- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2023 Tishler!
2024
Guido van Rossum9089b272001-03-02 06:49:50 +00002025- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2026 Schwertberger! See RISCOS/README for more information -- it seems
2027 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002028 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002029
Tim Peters25a9ce32001-02-19 07:06:36 +00002030
Tim Petersd7b5e882001-01-25 03:36:26 +00002031What's New in Python 2.1 alpha 2?
2032=================================
Tim Peters40ead762001-01-27 05:35:26 +00002033
Tim Petersd7b5e882001-01-25 03:36:26 +00002034Core language, builtins, and interpreter
2035
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002036- Scopes nest. If a name is used in a function or class, but is not
2037 local, the definition in the nearest enclosing function scope will
2038 be used. One consequence of this change is that lambda statements
2039 could reference variables in the namespaces where the lambda is
2040 defined. In some unusual cases, this change will break code.
2041
2042 In all previous version of Python, names were resolved in exactly
2043 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002044 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002045 function A is defined within a function B, the names bound in B are
2046 not visible in A. The new rules make names bound in B visible in A,
2047 unless A contains a name binding that hides the binding in B.
2048
2049 Section 4.1 of the reference manual describes the new scoping rules
2050 in detail. The test script in Lib/test/test_scope.py demonstrates
2051 some of the effects of the change.
2052
2053 The new rules will cause existing code to break if it defines nested
2054 functions where an outer function has local variables with the same
2055 name as globals or builtins used by the inner function. Example:
2056
2057 def munge(str):
2058 def helper(x):
2059 return str(x)
2060 if type(str) != type(''):
2061 str = helper(str)
2062 return str.strip()
2063
2064 Under the old rules, the name str in helper() is bound to the
2065 builtin function str(). Under the new rules, it will be bound to
2066 the argument named str and an error will occur when helper() is
2067 called.
2068
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002069- The compiler will report a SyntaxError if "from ... import *" occurs
2070 in a function or class scope. The language reference has documented
2071 that this case is illegal, but the compiler never checked for it.
2072 The recent introduction of nested scope makes the meaning of this
2073 form of name binding ambiguous. In a future release, the compiler
2074 may allow this form when there is no possibility of ambiguity.
2075
Tim Peters40ead762001-01-27 05:35:26 +00002076- repr(string) is easier to read, now using hex escapes instead of octal,
2077 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2078
2079 >>> "\texample \r\n" + chr(0) + chr(255)
2080 '\texample \r\n\x00\xff' # in 2.1
2081 '\011example \015\012\000\377' # in 2.0
2082
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002083- Functions are now compared and hashed by identity, not by value, since
2084 the func_code attribute is writable.
2085
Fred Drakefb9d7122001-02-01 20:00:40 +00002086- Weak references (PEP 205) have been added. This involves a few
2087 changes in the core, an extension module (_weakref), and a Python
2088 module (weakref). The weakref module is the public interface. It
2089 includes support for "explicit" weak references, proxy objects, and
2090 mappings with weakly held values.
2091
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002092- A 'continue' statement can now appear in a try block within the body
2093 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002094 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002095
Tim Petersd7b5e882001-01-25 03:36:26 +00002096Standard library
2097
Barry Warsaw30dbd142001-01-31 22:14:01 +00002098- mailbox.py now has a new class, PortableUnixMailbox which is
2099 identical to UnixMailbox but uses a more portable scheme for
2100 determining From_ separators. Also, the constructors for all the
2101 classes in this module have a new optional `factory' argument, which
2102 is a callable used when new message classes must be instantiated by
2103 the next() method.
2104
Tim Petersd7b5e882001-01-25 03:36:26 +00002105- random.py is now self-contained, and offers all the functionality of
2106 the now-deprecated whrandom.py. See the docs for details. random.py
2107 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002108 and restoring the internal state of the generator; and jumpahead(n),
2109 for quickly forcing the internal state to be the same as if n calls to
2110 random() had been made. The latter is particularly useful for multi-
2111 threaded programs, creating one instance of the random.Random() class for
2112 each thread, then using .jumpahead() to force each instance to use a
2113 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002114
Tim Peters0de88fc2001-02-01 04:59:18 +00002115- random.py's seed() function is new. For bit-for-bit compatibility with
2116 prior releases, use the whseed function instead. The new seed function
2117 addresses two problems: (1) The old function couldn't produce more than
2118 about 2**24 distinct internal states; the new one about 2**45 (the best
2119 that can be done in the Wichmann-Hill generator). (2) The old function
2120 sometimes produced identical internal states when passed distinct
2121 integers, and there was no simple way to predict when that would happen;
2122 the new one guarantees to produce distinct internal states for all
2123 arguments in [0, 27814431486576L).
2124
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002125- The socket module now supports raw packets on Linux. The socket
2126 family is AF_PACKET.
2127
Tim Peters9ea17ac2001-02-02 05:57:15 +00002128- test_capi.py is a start at running tests of the Python C API. The tests
2129 are implemented by the new Modules/_testmodule.c.
2130
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002131- A new extension module, _symtable, provides provisional access to the
2132 internal symbol table used by the Python compiler. A higher-level
2133 interface will be added on top of _symtable in a future release.
2134
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002135- Removed the obsolete soundex module.
2136
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002137- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2138 the isSameNode method; NamedNodeMap the get method.
2139
2140- xml.sax.expatreader supports the lexical handler property; it
2141 generates comment, startCDATA, and endCDATA events.
2142
Tim Petersee826f82001-01-31 19:39:44 +00002143Windows changes
2144
2145- Build procedure: the zlib project is built in a different way that
2146 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002147 the zlib binary used. See PCbuild\readme.txt for details. Your old
2148 zlib-related directories can be deleted; you'll need to download fresh
2149 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002150
Tim Peters9ea17ac2001-02-02 05:57:15 +00002151- Build: New subproject _test for the benefit of test_capi.py (see above).
2152
Tim Petersb16c56f2001-02-02 21:24:51 +00002153- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2154 interface to some Python compiler internals).
2155
2156- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002157 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002158
Tim Petersa3a3a032000-11-30 05:22:44 +00002159What's New in Python 2.1 alpha 1?
2160=================================
2161
2162Core language, builtins, and interpreter
2163
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002164- There is a new Unicode companion to the PyObject_Str() API
2165 called PyObject_Unicode(). It behaves in the same way as the
2166 former, but assures that the returned value is an Unicode object
2167 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002168
Guido van Rossumf98eda02001-01-17 15:54:45 +00002169- The comparison operators support "rich comparison overloading" (PEP
2170 207). C extension types can provide a rich comparison function in
2171 the new tp_richcompare slot in the type object. The cmp() function
2172 and the C function PyObject_Compare() first try the new rich
2173 comparison operators before trying the old 3-way comparison. There
2174 is also a new C API PyObject_RichCompare() (which also falls back on
2175 the old 3-way comparison, but does not constrain the outcome of the
2176 rich comparison to a Boolean result).
2177
2178 The rich comparison function takes two objects (at least one of
2179 which is guaranteed to have the type that provided the function) and
2180 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2181 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2182 object, which may be NotImplemented (in which case the tp_compare
2183 slot function is used as a fallback, if defined).
2184
2185 Classes can overload individual comparison operators by defining one
2186 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002187 __ge__. There are no explicit "reflected argument" versions of
2188 these; instead, __lt__ and __gt__ are each other's reflection,
2189 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2190 reflection (similar at the C level). No other implications are
2191 made; in particular, Python does not assume that == is the Boolean
2192 inverse of !=, or that < is the Boolean inverse of >=. This makes
2193 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002194
2195 Classes or types that want to implement (in)equality tests but not
2196 the ordering operators (i.e. unordered types) should implement ==
2197 and !=, and raise an error for the ordering operators.
2198
Guido van Rossuma88479f2001-01-18 14:28:08 +00002199 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002200 Boolean; e.g. a matrix type might want to return a matrix of bits
2201 for A < B, giving elementwise comparisons. Such types should ensure
2202 that any interpretation of their value in a Boolean context raises
2203 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2204 at the C level) to always raise an exception.
2205
Guido van Rossuma88479f2001-01-18 14:28:08 +00002206- Complex numbers use rich comparisons to define == and != but raise
2207 an exception for <, <=, > and >=. Unfortunately, this also means
2208 that cmp() of two complex numbers raises an exception when the two
2209 numbers differ. Since it is not mathematically meaningful to compare
2210 complex numbers except for equality, I hope that this doesn't break
2211 too much code.
2212
Tim Peters3389f192001-02-18 08:48:49 +00002213- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002214 not defined by the language, other than that it's arbitrary but
2215 consistent (see the Reference Manual). An implementation detail changed
2216 in 2.1a1 such that None now compares less than any other object. Code
2217 relying on this new behavior (like code that relied on the previous
2218 behavior) does so at its own risk.
2219
Barry Warsaw573b5412001-01-15 20:43:18 +00002220- Functions and methods now support getting and setting arbitrarily
2221 named attributes (PEP 232). Functions have a new __dict__
2222 (a.k.a. func_dict) which hold the function attributes. Methods get
2223 and set attributes on their underlying im_func. It is a TypeError
2224 to set an attribute on a bound method.
2225
Guido van Rossum051e3352001-01-15 19:11:10 +00002226- The xrange() object implementation has been improved so that
2227 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2228 limitation that in this case len(xrange(sys.maxint)) can't be
2229 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2230 work fine as long as the index i doesn't actually reach 2**31.
2231 (Python uses regular ints for sequence and string indices; fixing
2232 that is much more work.)
2233
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002234- Two changes to from...import:
2235
Guido van Rossumba381232001-02-03 15:06:40 +00002236 1) "from M import X" now works even if (after loading module M)
2237 sys.modules['M'] is not a real module; it's basically a getattr()
2238 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002239
2240 2) "from M import *" now looks for M.__all__ to decide which names to
2241 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2242 filters out names starting with '_' as before. Whether or not
2243 __all__ exists, there's no restriction on the type of M.
2244
Guido van Rossumf61f1662001-01-10 20:13:55 +00002245- File objects have a new method, xreadlines(). This is the fastest
2246 way to iterate over all lines in a file:
2247
2248 for line in file.xreadlines():
2249 ...do something to line...
2250
2251 See the xreadlines module (mentioned below) for how to do this for
2252 other file-like objects.
2253
2254- Even if you don't use file.xreadlines(), you may expect a speedup on
2255 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002256 quite a bit in platform-specific ways: on systems (like Linux) that
2257 support flockfile(), getc_unlocked(), and funlockfile(), those are
2258 used by default. On systems (like Windows) without getc_unlocked(),
2259 a complicated (but still thread-safe) method using fgets() is used by
2260 default.
2261
Tim Petersd52269b2001-01-25 06:23:18 +00002262 You can force use of the fgets() method by #define'ing
2263 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002264 getc_unlocked()).
2265
Tim Petersd52269b2001-01-25 06:23:18 +00002266 You can force fgets() not to be used by #define'ing
2267 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002268 test_bufio.py fails -- and let us know if it does!).
2269
2270- In addition, the fileinput module, while still slower than the other
2271 methods on most platforms, has been sped up too, by using
2272 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002273
2274- Support for run-time warnings has been added, including a new
2275 command line option (-W) to specify the disposition of warnings.
2276 See the description of the warnings module below.
2277
2278- Extensive changes have been made to the coercion code. This mostly
2279 affects extension modules (which can now implement mixed-type
2280 numerical operators without having to use coercion), but
2281 occasionally, in boundary cases the coercion semantics have changed
2282 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002283 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002284 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002285 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002286
Guido van Rossumf98eda02001-01-17 15:54:45 +00002287- In connection with the coercion changes, a new built-in singleton
2288 object, NotImplemented is defined. This can be returned for
2289 operations that wish to indicate they are not implemented for a
2290 particular combination of arguments. From C, this is
2291 Py_NotImplemented.
2292
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002293- The interpreter accepts now bytecode files on the command line even
2294 if they do not have a .pyc or .pyo extension. On Linux, after executing
2295
Martin v. Löwise214baa2001-02-04 22:37:56 +00002296import imp,sys,string
2297magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2298reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2299open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002300
2301 any byte code file can be used as an executable (i.e. as an argument
2302 to execve(2)).
2303
Tim Peters9940b802000-12-01 07:59:35 +00002304- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002305 character. In 1.6 and earlier, they never produced a sign,
2306 and raised an error if the value of the long was too large
2307 to fit in a Python int. In 2.0, they produced a sign if and
2308 only if too large to fit in an int. This was inconsistent
2309 across platforms (because the size of an int varies across
2310 platforms), and inconsistent with hex() and oct(). Example:
2311
2312 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002313 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002314 'ffffffbe' # in 2.0 and before, on 32-bit machines
2315 >>> hex(-0x42L)
2316 '-0x42L' # in all versions of Python
2317
Tim Peters9940b802000-12-01 07:59:35 +00002318 The behavior of %d formats for negative Python longs remains
2319 the same as in 2.0 (although in 1.6 and before, they raised
2320 an error if the long didn't fit in a Python int).
2321
2322 %u formats don't make sense for Python longs, but are allowed
2323 and treated the same as %d in 2.1. In 2.0, a negative long
2324 formatted via %u produced a sign if and only if too large to
2325 fit in an int. In 1.6 and earlier, a negative long formatted
2326 via %u raised an error if it was too big to fit in an int.
2327
Guido van Rossum3661d392000-12-12 22:10:31 +00002328- Dictionary objects have an odd new method, popitem(). This removes
2329 an arbitrary item from the dictionary and returns it (in the form of
2330 a (key, value) pair). This can be useful for algorithms that use a
2331 dictionary as a bag of "to do" items and repeatedly need to pick one
2332 item. Such algorithms normally end up running in quadratic time;
2333 using popitem() they can usually be made to run in linear time.
2334
Tim Peters36cdad12000-12-29 02:06:45 +00002335Standard library
2336
Thomas Woutersfe385252001-01-19 23:16:56 +00002337- In the time module, the time argument to the functions strftime,
2338 localtime, gmtime, asctime and ctime is now optional, defaulting to
2339 the current time (in the local timezone).
2340
Guido van Rossumda91f222001-01-15 16:36:08 +00002341- The ftplib module now defaults to passive mode, which is deemed a
2342 more useful default given that clients are often inside firewalls
2343 these days. Note that this could break if ftplib is used to connect
2344 to a *server* that is inside a firewall, from outside; this is
2345 expected to be a very rare situation. To fix that, you can call
2346 ftp.set_pasv(0).
2347
Martin v. Löwis10a27872001-01-13 09:54:41 +00002348- The module site now treats .pth files not only for path configuration,
2349 but also supports extensions to the initialization code: Lines starting
2350 with import are executed.
2351
Guido van Rossumf61f1662001-01-10 20:13:55 +00002352- There's a new module, warnings, which implements a mechanism for
2353 issuing and filtering warnings. There are some new built-in
2354 exceptions that serve as warning categories, and a new command line
2355 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2356 turns warnings into errors). warnings.warn(message[, category])
2357 issues a warning message; this can also be called from C as
2358 PyErr_Warn(category, message).
2359
2360- A new module xreadlines was added. This exports a single factory
2361 function, xreadlines(). The intention is that this code is the
2362 absolutely fastest way to iterate over all lines in an open
2363 file(-like) object:
2364
2365 import xreadlines
2366 for line in xreadlines.xreadlines(file):
2367 ...do something to line...
2368
2369 This is equivalent to the previous the speed record holder using
2370 file.readlines(sizehint). Note that if file is a real file object
2371 (as opposed to a file-like object), this is equivalent:
2372
2373 for line in file.xreadlines():
2374 ...do something to line...
2375
Tim Peters36cdad12000-12-29 02:06:45 +00002376- The bisect module has new functions bisect_left, insort_left,
2377 bisect_right and insort_right. The old names bisect and insort
2378 are now aliases for bisect_right and insort_right. XXX_right
2379 and XXX_left methods differ in what happens when the new element
2380 compares equal to one or more elements already in the list: the
2381 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002382 right. Code that doesn't care where equal elements end up should
2383 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002384
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002385- The new curses.panel module wraps the panel library that forms part
2386 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2387
Guido van Rossumf61f1662001-01-10 20:13:55 +00002388- The SocketServer module now sets the allow_reuse_address flag by
2389 default in the TCPServer class.
2390
2391- A new function, sys._getframe(), returns the stack frame pointer of
2392 the caller. This is intended only as a building block for
2393 higher-level mechanisms such as string interpolation.
2394
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002395- The pyexpat module supports a number of new handlers, which are
2396 available only in expat 1.2. If invocation of a callback fails, it
2397 will report an additional frame in the traceback. Parser objects
2398 participate now in garbage collection. If expat reports an unknown
2399 encoding, pyexpat will try to use a Python codec; that works only
2400 for single-byte charsets. The parser type objects is exposed as
2401 XMLParserObject.
2402
2403- xml.dom now offers standard definitions for symbolic node type and
2404 exception code constants, and a hierarchy of DOM exceptions. minidom
2405 was adjusted to use them.
2406
2407- The conformance of xml.dom.minidom to the DOM specification was
2408 improved. It detects a number of additional error cases; the
2409 previous/next relationship works even when the tree is modified;
2410 Node supports the normalize() method; NamedNodeMap, DocumentType and
2411 DOMImplementation classes were added; Element supports the
2412 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2413 method.
2414
Guido van Rossumf61f1662001-01-10 20:13:55 +00002415Build issues
2416
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002417- For Unix (and Unix-compatible) builds, configuration and building of
2418 extension modules is now greatly automated. Rather than having to
2419 edit the Modules/Setup file to indicate which modules should be
2420 built and where their include files and libraries are, a
2421 distutils-based setup.py script now takes care of building most
2422 extension modules. All extension modules built this way are built
2423 as shared libraries. Only a few modules that must be linked
2424 statically are still listed in the Setup file; you won't need to
2425 edit their configuration.
2426
2427- Python should now build out of the box on Cygwin. If it doesn't,
2428 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002429
2430- Python now always uses its own (renamed) implementation of getopt()
2431 -- there's too much variation among C library getopt()
2432 implementations.
2433
2434- C++ compilers are better supported; the CXX macro is always set to a
2435 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002436
Tim Petersd92dfe02000-12-12 01:18:41 +00002437Windows changes
2438
2439- select module: By default under Windows, a select() call
2440 can specify no more than 64 sockets. Python now boosts
2441 this Microsoft default to 512. If you need even more than
2442 that, see the MS docs (you'll need to #define FD_SETSIZE
2443 and recompile Python from source).
2444
Guido van Rossumf61f1662001-01-10 20:13:55 +00002445- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2446 subdirectory is no more!
2447
Tim Petersa3a3a032000-11-30 05:22:44 +00002448
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002449What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002450=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002451
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002452Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002453changes are in the file HISTORY. If you are making the jump directly
2454from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2455HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002456
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002457Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2458the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2459http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002460
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002461--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002462
2463======================================================================
2464
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002465What's new in 2.0 (since release candidate 1)?
2466==============================================
2467
2468Standard library
2469
2470- The copy_reg module was modified to clarify its intended use: to
2471 register pickle support for extension types, not for classes.
2472 pickle() will raise a TypeError if it is passed a class.
2473
2474- Fixed a bug in gettext's "normalize and expand" code that prevented
2475 it from finding an existing .mo file.
2476
2477- Restored support for HTTP/0.9 servers in httplib.
2478
Tim Peters989b7b92000-10-16 20:24:53 +00002479- The math module was changed to stop raising OverflowError in case of
2480 underflow, and return 0 instead in underflow cases. Whether Python
2481 used to raise OverflowError in case of underflow was platform-
2482 dependent (it did when the platform math library set errno to ERANGE
2483 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002484
2485- Fixed a bug in StringIO that occurred when the file position was not
2486 at the end of the file and write() was called with enough data to
2487 extend past the end of the file.
2488
2489- Fixed a bug that caused Tkinter error messages to get lost on
2490 Windows. The bug was fixed by replacing direct use of
2491 interp->result with Tcl_GetStringResult(interp).
2492
2493- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2494 redirect response.
2495
2496- Several changes were made to distutils: Some debugging code was
2497 removed from util. Fixed the installer used when an external zip
2498 program (like WinZip) is not found; the source code for this
2499 installer is in Misc/distutils. check_lib() was modified to behave
2500 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2501 test for whether installed modules are on sys.path was changed to
2502 use both normcase() and normpath().
2503
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002504- Several minor bugs were fixed in the xml package (the minidom,
2505 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002506
2507- The regression test driver (regrtest.py) behavior when invoked with
2508 -l changed: It now reports a count of objects that are recognized as
2509 garbage but not freed by the garbage collector.
2510
Tim Peters989b7b92000-10-16 20:24:53 +00002511- The regression test for the math module was changed to test
2512 exceptional behavior when the test is run in verbose mode. Python
2513 cannot yet guarantee consistent exception behavior across platforms,
2514 so the exception part of test_math is run only in verbose mode, and
2515 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002516
2517Internals
2518
2519- PyOS_CheckStack() has been disabled on Win64, where it caused
2520 test_sre to fail.
2521
2522Build issues
2523
2524- Changed compiler flags, so that gcc is always invoked with -Wall and
2525 -Wstrict-prototypes. Users compiling Python with GCC should see
2526 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002527 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002528 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002529
Tim Petersa3a3a032000-11-30 05:22:44 +00002530- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002531
2532Tools and other miscellany
2533
2534- The compiler in Tools/compiler was updated to support the new
2535 language features introduced in 2.0: extended print statement, list
2536 comprehensions, and augmented assignments. The new compiler should
2537 also be backwards compatible with Python 1.5.2; the compiler will
2538 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002539 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002540
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002541What's new in 2.0 release candidate 1 (since beta 2)?
2542=====================================================
2543
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002544What is release candidate 1?
2545
2546We believe that release candidate 1 will fix all known bugs that we
2547intend to fix for the 2.0 final release. This release should be a bit
2548more stable than the previous betas. We would like to see even more
2549widespread testing before the final release, so we are producing this
2550release candidate. The final release will be exactly the same unless
2551any show-stopping (or brown bag) bugs are found by testers of the
2552release candidate.
2553
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002554All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002555to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002556
2557Core language, builtins, and interpreter
2558
2559- A bug that caused crashes when __coerce__ was used with augmented
2560 assignment, e.g. +=, was fixed.
2561
2562- Raise ZeroDivisionError when raising zero to a negative number,
2563 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2564 power operator and the result of math.pow(0.0, -2.0) will vary by
2565 platform. On Linux, it raises a ValueError.
2566
2567- A bug in Unicode string interpolation was fixed that occasionally
2568 caused errors with formats including "%%". For example, the
2569 following expression "%% %s" % u"abc" no longer raises a TypeError.
2570
2571- Compilation of deeply nested expressions raises MemoryError instead
2572 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2573
2574- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2575 rendering them useless. They are now written in binary mode again.
2576
2577Standard library
2578
2579- Keyword arguments are now accepted for most pattern and match object
2580 methods in SRE, the standard regular expression engine.
2581
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002582- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002583 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002584
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002585- Several bugs in the Unicode handling and error handling in _tkinter
2586 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002587
2588- Fix memory management errors in Merge() and Tkapp_Call() routines.
2589
2590- Several changes were made to cStringIO to make it compatible with
2591 the file-like object interface and with StringIO. If operations are
2592 performed on a closed object, an exception is raised. The truncate
2593 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002594 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002595
2596- There were many changes made to the linuxaudiodev module and its
2597 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002598 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002599
2600 Note that this module is named poorly, because it should work
2601 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002602 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002603
2604 The module now raises exceptions when errors occur instead of
2605 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2606 audio) and defines a getptr() method that calls the
2607 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2608
2609- The library_version attribute, introduced in an earlier beta, was
2610 removed because it can not be supported with early versions of the C
2611 readline library, which provides no way to determine the version at
2612 compile-time.
2613
2614- The binascii module is now enabled on Win64.
2615
Tim Peters46446d62000-10-09 21:19:31 +00002616- tokenize.py no longer suffers "recursion depth" errors when parsing
2617 programs with very long string literals.
2618
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002619Internals
2620
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002621- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002622 which is called when the interpreter starts up to determine where
2623 the standard library is installed. These vulnerabilities affect all
2624 previous versions of Python and can be exploited by setting very
2625 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2626 setuid Python script, although use of the wrapper in
2627 Misc/setuid-prog.c will eliminate the vulnerability.
2628
2629- Fixed garbage collection bugs in instance creation that were
2630 triggered when errors occurred during initialization. The solution,
2631 applied in cPickle and in PyInstance_New(), is to call
2632 PyObject_GC_Init() after the initialization of the object's
2633 container attributes is complete.
2634
2635- pyexpat adds definitions of PyModule_AddStringConstant and
2636 PyModule_AddObject if the Python version is less than 2.0, which
2637 provides compatibility with PyXML on Python 1.5.2.
2638
2639- If the platform has a bogus definition for LONG_BIT (the number of
2640 bits in a long), an error will be reported at compile time.
2641
2642- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2643 collection crashes and possibly other, unreported crashes.
2644
2645- Fixed a memory leak in _PyUnicode_Fini().
2646
2647Build issues
2648
2649- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002650 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002651 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002652
2653- The mmap.PAGESIZE constant is now initialized using sysconf when
2654 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2655
2656- The md5 file should now compile on all platforms.
2657
2658- The select module now compiles on platforms that do not define
2659 POLLRDNORM and related constants.
2660
2661- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002662 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002663
Jeremy Hylton10921202000-10-09 18:34:12 +00002664- BeOS: A number of changes were made to the build and installation
2665 process. ar-fake now operates on a directory of object files.
2666 dl_export.h is gone, and its macros now appear on the mwcc command
2667 line during build on PPC BeOS.
2668
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002669- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002670 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002671
2672- Cygwin: Support for shared libraries, Tkinter, and sockets.
2673
2674- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2675
2676Tools and other miscellany
2677
2678- Removed debugging prints from main used with freeze.
2679
Tim Peters46446d62000-10-09 21:19:31 +00002680- IDLE auto-indent no longer crashes when it encounters Unicode
2681 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002682
2683What's new in 2.0 beta 2 (since beta 1)?
2684========================================
2685
2686Core language, builtins, and interpreter
2687
Tim Peters482c0212000-09-26 06:33:09 +00002688- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002689 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002690
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002691- Add -h and -V command line options to print the usage message and
2692 Python version number and exit immediately.
2693
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002694- eval() and exec accept Unicode objects as code parameters.
2695
2696- getattr() and setattr() now also accept Unicode objects for the
2697 attribute name, which are converted to strings using the default
2698 encoding before lookup.
2699
2700- Multiplication on string and Unicode now does proper bounds
2701 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2702 string is too long."
2703
2704- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002705 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002706
Jeremy Hylton1b618592000-09-26 05:32:36 +00002707
2708Standard library and extensions
2709
Guido van Rossum5b08f132001-04-16 02:05:23 +00002710- socket module: the OpenSSL code now adds support for RAND_status()
2711 and EGD (Entropy Gathering Device).
2712
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002713- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002714 argument checking; it still takes no arguments.
2715
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002716- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002717
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002718- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002719
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002720- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002721
2722- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002723 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002724
2725- copy: Copy Unicode objects atomically.
2726
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002727- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002728
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002729- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002730
Fred Drake67233bc2000-09-26 16:40:27 +00002731- dbm: Add get() and setdefault() methods to dbm object. Add constant
2732 `library' to module that names the library used. Added doc strings
2733 and method names to error messages. Uses configure to determine
2734 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2735 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002736
2737- distutils: Update to version 0.9.3.
2738
2739- dl: Add several dl.RTLD_ constants.
2740
2741- fpectl: Now supported on FreeBSD.
2742
2743- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2744 found by the collector will be saved in gc.garbage. This is useful
2745 for debugging a program that creates reference cycles.
2746
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002747- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002748 of HTTP class. Do not close socket on zero-length response. Do not
2749 crash when server sends invalid content-length header.
2750
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002751- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002752
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002753- marshal: When reading a short, sign-extend on platforms where shorts
2754 are bigger than 16 bits. When reading a long, repair the unportable
2755 sign extension that was being done for 64-bit machines. (It assumed
2756 that signed right shift sign-extends.)
2757
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002758- operator: Add contains(), invert(), __invert__() as aliases for
2759 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002760
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002761- os: Add support for popen2() and popen3() on all platforms where
2762 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002763
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002764- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002765 clicking on a file in Explorer (or passing the file name to the
2766 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002767
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002768- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002769 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002770
2771- pickle: Now raises ValueError when an invalid pickle that contains
2772 a non-string repr where a string repr was expected. This behavior
2773 matches cPickle.
2774
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002775- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002776
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002777- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778
2779- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002780 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002781 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002782
2783- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002784 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002785
2786- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002787 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002788 few cycles during startup since the first call to
2789 setdefaultencoding() will initialize the codec registry and the
2790 encodings package.
2791
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792- socket: Support for size hint in readlines() method of object returned
2793 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002794
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002795- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002796 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002797 is followed by whitespace.
2798
Tim Petersa3a3a032000-11-30 05:22:44 +00002799- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002800
2801- struct: Check ranges for bytes and shorts.
2802
2803- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002804 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002805
2806- Tkinter: Image objects are now guaranteed to have unique ids. Set
2807 event.delta to zero if Tk version doesn't support mousewheel.
2808 Removed some debugging prints.
2809
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002810- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002811
Fred Drake67233bc2000-09-26 16:40:27 +00002812- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002813 which works around a bug in Norton AntiVirus 2000 that leads directly
2814 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002815
2816- xml: New version detection code allows PyXML to override standard
2817 XML package if PyXML version is greater than 0.6.1.
2818
Fred Drake64bb3802000-09-26 16:21:35 +00002819- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2820 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2821 tree only for nodes which are sufficiently interesting to a specific
2822 application. Does not provide the HTML-specific extensions. Still
2823 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002824
Fred Drake64bb3802000-09-26 16:21:35 +00002825- xml.sax: SAX 2 support for Python, including all the handler
2826 interfaces needed to process XML 1.0 compliant XML. Some
2827 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002828
Fred Drake64bb3802000-09-26 16:21:35 +00002829- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2830 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002831
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002832
Jeremy Hylton1b618592000-09-26 05:32:36 +00002833C API
2834
2835- Add three new convenience functions for module initialization --
2836 PyModule_AddObject(), PyModule_AddIntConstant(), and
2837 PyModule_AddStringConstant().
2838
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002839- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002840 removed and add #error to Python.h if NULL isn't defined after
2841 #include of stdio.h.
2842
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002843- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002844 backwards compatibility (at the source level) with old extensions.
2845
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002846- A wrapper API was added for signal() and sigaction(). Instead of
2847 either function, always use PyOS_getsig() to get a signal handler
2848 and PyOS_setsig() to set one. A new convenience typedef
2849 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002850
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002851- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002852 internal data buffer and size of a string object -- or the default
2853 encoded version of a Unicode object.
2854
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002855- PyString_Size() and PyString_AsString() accept Unicode objects.
2856
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002857- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002858 exists). INT_MAX and LONG_MAX will always be defined, even if
2859 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002860
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002861- PyFloat_FromString takes a second argument, pend, that was
2862 effectively useless. It is now officially useless but preserved for
2863 backwards compatibility. If the pend argument is not NULL, *pend is
2864 set to NULL.
2865
2866- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2867 for the attribute name. See note on getattr() above.
2868
2869- A few bug fixes to argument processing for Unicode.
2870 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2871 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2872 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002873 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002874
2875- Py_BuildValue accepts B format (for bgen-generated code).
2876
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002877
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878Internals
2879
2880- On Unix, fix code for finding Python installation directory so that
2881 it works when argv[0] is a relative path.
2882
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002883- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002884 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002885 rather than by generating a copy of the object.
2886
Tim Peters482c0212000-09-26 06:33:09 +00002887- Several of the internal Unicode tables are much smaller now, and
2888 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002889
Jeremy Hylton97693b02000-09-26 17:42:51 +00002890- In the garbage collector: Fixed bug in collection of tuples. Fixed
2891 bug that caused some instances to be removed from the container set
2892 while they were still live. Fixed parsing in gc.set_debug() for
2893 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002894
2895- Fixed refcount problem in instance deallocation that only occurred
2896 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2897
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002898- On Windows, getpythonregpath is now protected against null data in
2899 registry key.
2900
2901- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002902 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002903
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002904
Jeremy Hylton1b618592000-09-26 05:32:36 +00002905Build and platform-specific issues
2906
2907- Better support of GNU Pth via --with-pth configure option.
2908
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002909- Python/C API now properly exposed to dynamically-loaded extension
2910 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002911
2912- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2913 Don't define MS_SYNC to be zero when it is undefined. Added missing
2914 prototypes in posixmodule.c.
2915
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002916- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002917 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002918
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002919- Fix largefile support on older NetBSD systems and OpenBSD by adding
2920 define for TELL64.
2921
2922
2923Tools and other miscellany
2924
2925- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2926
2927- freeze: The modulefinder now works with 2.0 opcodes.
2928
Tim Petersa3a3a032000-11-30 05:22:44 +00002929- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002930 Move hackery of sys.argv until after the Tk instance has been
2931 created, which allows the application-specific Tkinter
2932 initialization to be executed if present; also pass an explicit
2933 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002934
Jeremy Hylton1b618592000-09-26 05:32:36 +00002935
2936What's new in 2.0 beta 1?
2937=========================
2938
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002939Source Incompatibilities
2940------------------------
2941
2942None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2943such as single-argument append(), connect() and bind(), and changes to
2944str(long) and repr(float).
2945
2946
2947Binary Incompatibilities
2948------------------------
2949
2950- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2951with Python 2.0; these extensions will have to be rebuilt for Python
29522.0.
2953
2954- On Windows, attempting to import a third party extension built for
2955Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2956can do about this. Check your PYTHONPATH environment variable!
2957
2958- Python bytecode files (*.pyc and *.pyo) are not compatible between
2959releases.
2960
2961
2962Overview of Changes Since 1.6
2963-----------------------------
2964
2965There are many new modules (including brand new XML support through
2966the xml package, and i18n support through the gettext module); a list
2967of all new modules is included below. Lots of bugs have been fixed.
2968
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002969The process for making major new changes to the language has changed
2970since Python 1.6. Enhancements must now be documented by a Python
2971Enhancement Proposal (PEP) before they can be accepted.
2972
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002973There are several important syntax enhancements, described in more
2974detail below:
2975
2976 - Augmented assignment, e.g. x += 1
2977
2978 - List comprehensions, e.g. [x**2 for x in range(10)]
2979
2980 - Extended import statement, e.g. import Module as Name
2981
2982 - Extended print statement, e.g. print >> file, "Hello"
2983
2984Other important changes:
2985
2986 - Optional collection of cyclical garbage
2987
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002988Python Enhancement Proposal (PEP)
2989---------------------------------
2990
2991PEP stands for Python Enhancement Proposal. A PEP is a design
2992document providing information to the Python community, or describing
2993a new feature for Python. The PEP should provide a concise technical
2994specification of the feature and a rationale for the feature.
2995
2996We intend PEPs to be the primary mechanisms for proposing new
2997features, for collecting community input on an issue, and for
2998documenting the design decisions that have gone into Python. The PEP
2999author is responsible for building consensus within the community and
3000documenting dissenting opinions.
3001
3002The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003003
3004Augmented Assignment
3005--------------------
3006
3007This must have been the most-requested feature of the past years!
3008Eleven new assignment operators were added:
3009
Guido van Rossume905e952000-09-05 12:42:46 +00003010 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003011
3012For example,
3013
3014 A += B
3015
3016is similar to
3017
3018 A = A + B
3019
3020except that A is evaluated only once (relevant when A is something
3021like dict[index].attr).
3022
3023However, if A is a mutable object, A may be modified in place. Thus,
3024if A is a number or a string, A += B has the same effect as A = A+B
3025(except A is only evaluated once); but if a is a list, A += B has the
3026same effect as A.extend(B)!
3027
3028Classes and built-in object types can override the new operators in
3029order to implement the in-place behavior; the not-in-place behavior is
3030used automatically as a fallback when an object doesn't implement the
3031in-place behavior. For classes, the method name is derived from the
3032method name for the corresponding not-in-place operator by inserting
3033an 'i' in front of the name, e.g. __iadd__ implements in-place
3034__add__.
3035
3036Augmented assignment was implemented by Thomas Wouters.
3037
3038
3039List Comprehensions
3040-------------------
3041
3042This is a flexible new notation for lists whose elements are computed
3043from another list (or lists). The simplest form is:
3044
3045 [<expression> for <variable> in <sequence>]
3046
Guido van Rossum56db0952000-09-06 23:34:25 +00003047For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003048This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003049
3050You can also add a condition:
3051
3052 [<expression> for <variable> in <sequence> if <condition>]
3053
3054For example, [w for w in words if w == w.lower()] would yield the list
3055of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003056than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003057
3058You can also have nested for loops and more than one 'if' clause. For
3059example, here's a function that flattens a sequence of sequences::
3060
3061 def flatten(seq):
3062 return [x for subseq in seq for x in subseq]
3063
3064 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3065
3066This prints
3067
3068 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3069
3070List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003071Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003072
3073
3074Extended Import Statement
3075-------------------------
3076
3077Many people have asked for a way to import a module under a different
3078name. This can be accomplished like this:
3079
3080 import foo
3081 bar = foo
3082 del foo
3083
3084but this common idiom gets old quickly. A simple extension of the
3085import statement now allows this to be written as follows:
3086
3087 import foo as bar
3088
3089There's also a variant for 'from ... import':
3090
3091 from foo import bar as spam
3092
3093This also works with packages; e.g. you can write this:
3094
3095 import test.regrtest as regrtest
3096
3097Note that 'as' is not a new keyword -- it is recognized only in this
3098context (this is only possible because the syntax for the import
3099statement doesn't involve expressions).
3100
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003101Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003102
3103
3104Extended Print Statement
3105------------------------
3106
3107Easily the most controversial new feature, this extension to the print
3108statement adds an option to make the output go to a different file
3109than the default sys.stdout.
3110
3111For example, to write an error message to sys.stderr, you can now
3112write:
3113
3114 print >> sys.stderr, "Error: bad dog!"
3115
3116As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003117evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003118
3119 print >> None, "Hello world"
3120
3121is equivalent to
3122
3123 print "Hello world"
3124
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003125Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003126
3127
3128Optional Collection of Cyclical Garbage
3129---------------------------------------
3130
3131Python is now equipped with a garbage collector that can hunt down
3132cyclical references between Python objects. It's no replacement for
3133reference counting; in fact, it depends on the reference counts being
3134correct, and decides that a set of objects belong to a cycle if all
3135their reference counts can be accounted for from their references to
3136each other. This devious scheme was first proposed by Eric Tiedemann,
3137and brought to implementation by Neil Schemenauer.
3138
3139There's a module "gc" that lets you control some parameters of the
3140garbage collection. There's also an option to the configure script
3141that lets you enable or disable the garbage collection. In 2.0b1,
3142it's on by default, so that we (hopefully) can collect decent user
3143experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003144performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003145off by default in the final 2.0 release.
3146
3147
3148Smaller Changes
3149---------------
3150
3151A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3152map(None, seq1, seq2, ...) when the sequences have the same length;
3153i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3154the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003155zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003156
3157sys.version_info is a tuple (major, minor, micro, level, serial).
3158
3159Dictionaries have an odd new method, setdefault(key, default).
3160dict.setdefault(key, default) returns dict[key] if it exists; if not,
3161it sets dict[key] to default and returns that value. Thus:
3162
3163 dict.setdefault(key, []).append(item)
3164
3165does the same work as this common idiom:
3166
3167 if not dict.has_key(key):
3168 dict[key] = []
3169 dict[key].append(item)
3170
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003171There are two new variants of SyntaxError that are raised for
3172indentation-related errors: IndentationError and TabError.
3173
3174Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3175escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003176
3177The limits on the size of expressions and file in Python source code
3178have been raised from 2**16 to 2**32. Previous versions of Python
3179were limited because the maximum argument size the Python VM accepted
3180was 2**16. This limited the size of object constructor expressions,
3181e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3182limit was raised thanks to a patch by Charles Waldman that effectively
3183fixes the problem. It is now much more likely that you will be
3184limited by available memory than by an arbitrary limit in Python.
3185
3186The interpreter's maximum recursion depth can be modified by Python
3187programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3188limit is the maximum number of recursive calls that can be made by
3189Python code. The limit exists to prevent infinite recursion from
3190overflowing the C stack and causing a core dump. The default value is
31911000. The maximum safe value for a particular platform can be found
3192by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003193
3194New Modules and Packages
3195------------------------
3196
3197atexit - for registering functions to be called when Python exits.
3198
3199imputil - Greg Stein's alternative API for writing custom import
3200hooks.
3201
3202pyexpat - an interface to the Expat XML parser, contributed by Paul
3203Prescod.
3204
3205xml - a new package with XML support code organized (so far) in three
3206subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3207would fill a volume. There's a special feature whereby a
3208user-installed package named _xmlplus overrides the standard
3209xmlpackage; this is intended to give the XML SIG a hook to distribute
3210backwards-compatible updates to the standard xml package.
3211
3212webbrowser - a platform-independent API to launch a web browser.
3213
3214
Guido van Rossume905e952000-09-05 12:42:46 +00003215Changed Modules
3216---------------
3217
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003218array -- new methods for array objects: count, extend, index, pop, and
3219remove
3220
3221binascii -- new functions b2a_hex and a2b_hex that convert between
3222binary data and its hex representation
3223
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003224calendar -- Many new functions that support features including control
3225over which day of the week is the first day, returning strings instead
3226of printing them. Also new symbolic constants for days of week,
3227e.g. MONDAY, ..., SUNDAY.
3228
3229cgi -- FieldStorage objects have a getvalue method that works like a
3230dictionary's get method and returns the value attribute of the object.
3231
3232ConfigParser -- The parser object has new methods has_option,
3233remove_section, remove_option, set, and write. They allow the module
3234to be used for writing config files as well as reading them.
3235
3236ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003237optionally support the RFC 959 REST command.
3238
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003239gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003240
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003241httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3242the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003243
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003244locale -- implement getdefaultlocale for Win32 and Macintosh
3245
3246marshal -- no longer dumps core when marshaling deeply nested or
3247recursive data structures
3248
3249os -- new functions isatty, seteuid, setegid, setreuid, setregid
3250
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003251os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3252support under Unix.
3253
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003254os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003255
3256os.path -- fix semantics of os.path.commonprefix
3257
3258smtplib -- support for sending very long messages
3259
3260socket -- new function getfqdn()
3261
3262readline -- new functions to read, write and truncate history files.
3263The readline section of the library reference manual contains an
3264example.
3265
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003266select -- add interface to poll system call
3267
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003268shutil -- new copyfileobj function
3269
3270SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3271HTTP server.
3272
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003273Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003274
3275urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003276e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003277
3278whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003279
3280
3281Obsolete Modules
3282----------------
3283
3284None. However note that 1.6 made a whole slew of modules obsolete:
3285stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3286poly, zmod, strop, util, whatsound.
3287
3288
3289Changed, New, Obsolete Tools
3290----------------------------
3291
Tim Peters8b092332000-09-05 20:15:25 +00003292None.
Guido van Rossume905e952000-09-05 12:42:46 +00003293
3294
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003295C-level Changes
3296---------------
3297
3298Several cleanup jobs were carried out throughout the source code.
3299
3300All C code was converted to ANSI C; we got rid of all uses of the
3301Py_PROTO() macro, which makes the header files a lot more readable.
3302
3303Most of the portability hacks were moved to a new header file,
3304pyport.h; several other new header files were added and some old
3305header files were removed, in an attempt to create a more rational set
3306of header files. (Few of these ever need to be included explicitly;
3307they are all included by Python.h.)
3308
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003309Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003310and Win64, especially for the new Intel Itanium processor. Mick also
3311added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003312
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003313The C APIs to return an object's size have been update to consistently
3314use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3315previous versions, the abstract interfaces used PyXXX_Length and the
3316concrete interfaces used PyXXX_Size. The old names,
3317e.g. PyObject_Length, are still available for backwards compatibility
3318at the API level, but are deprecated.
3319
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003320The PyOS_CheckStack function has been implemented on Windows by
3321Fredrik Lundh. It prevents Python from failing with a stack overflow
3322on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003323
3324The GC changes resulted in creation of two new slots on object,
3325tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003326the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003327
3328The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003329C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003330
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003331PyErr_Format has been updated to automatically calculate the size of
3332the buffer needed to hold the formatted result string. This change
3333prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003334
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003335New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003336
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003337PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3338that are the same as their non-Ex counterparts except they take an
3339extra flag argument that tells them to close the file when done.
3340
3341XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003342
Tim Peters8b092332000-09-05 20:15:25 +00003343
3344Windows Changes
3345---------------
3346
3347New popen2/popen3/peopen4 in os module (see Changed Modules above).
3348
3349os.popen is much more usable on Windows 95 and 98. See Microsoft
3350Knowledge Base article Q150956. The Win9x workaround described there
3351is implemented by the new w9xpopen.exe helper in the root of your
3352Python installation. Note that Python uses this internally; it is not
3353a standalone program.
3354
3355Administrator privileges are no longer required to install Python
3356on Windows NT or Windows 2000. If you have administrator privileges,
3357Python's registry info will be written under HKEY_LOCAL_MACHINE.
3358Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003359under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003360uses of Python, but will prevent some advanced uses from working
3361(for example, running a Python script as an NT service, or possibly
3362from CGI).
3363
3364[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3365installer; instead, it installs the needed Tcl/Tk files directly in the
3366Python directory. If you already have a Tcl/Tk installation, this
3367wastes some disk space (about 4 Megs) but avoids problems with
3368conflicting Tcl/Tk installations, and makes it much easier for Python
3369to ensure that Tcl/Tk can find all its files.
3370
3371[This was new in 1.6] The Windows installer now installs by default in
3372\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3373
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003374
3375Updates to the changes between 1.5.2 and 1.6
3376--------------------------------------------
3377
3378The 1.6 NEWS file can't be changed after the release is done, so here
3379is some late-breaking news:
3380
3381New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3382and changes to getlocale() and setlocale().
3383
3384The new module is now enabled per default.
3385
3386It is not true that the encodings codecs cannot be used for normal
3387strings: the string.encode() (which is also present on 8-bit strings
3388!) allows using them for 8-bit strings too, e.g. to convert files from
3389cp1252 (Windows) to latin-1 or vice-versa.
3390
3391Japanese codecs are available from Tamito KAJIYAMA:
3392http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3393
3394
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003395======================================================================