blob: e6fc808f1b9ae8778c36e1d517e583d2706421ea [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 Rossum49042042002-04-13 00:59:05 +00009- String methods lstrip(), rstrip() and strip() now take an optional
10 argument that specifies the characters to strip. For example,
11 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
12
Guido van Rossumc69343b2002-04-12 19:22:48 +000013- Added a new dict method pop(key). This removes and returns the
14 value corresponding to key. [SF patch #539949]
15
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000016- Changed new-style class instantiation so that when C's __new__
17 method returns something that's not a C instance, its __init__ is
18 not called. [SF bug #537450]
19
Guido van Rossum181e41a2002-04-06 00:23:25 +000020- Fixed super() to work correctly with class methods. [SF bug #535444]
21
Guido van Rossum47834462002-04-04 15:21:33 +000022- A new built-in type, bool, has been added, as well as built-in
23 names for its two values, True and False. Comparisons and sundry
24 other operations that return a truth value have been changed to
25 return a bool instead. Read PEP 285 for an explanantion of why this
26 is backward compatible.
27
Guido van Rossum95b62a62002-03-29 01:07:24 +000028- Fixed two bugs reported as SF #535905: under certain conditions,
29 deallocating a deeply nested structure could cause a segfault in the
30 garbage collector, due to interaction with the "trashcan" code;
31 access to the current frame during destruction of a local variable
32 could access a pointer to freed memory.
33
Neil Schemenauer9d50d132002-03-22 17:06:59 +000034- The optional object allocator has been enabled by default.
35
Guido van Rossum8c842552002-03-14 23:05:54 +000036- If you try to pickle an instance of a class that has __slots__ but
37 doesn't define or override __getstate__, a TypeError is now raised.
38 This is done by adding a bozo __getstate__ to the class that always
39 raises TypeError. (Before, this would appear to be pickled, but the
40 state of the slots would be lost.)
41
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000042- PyErr_Display will provide file and line information for all exceptions
43 that have an attribute print_file_and_line, not just SyntaxErrors.
44
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000045- The UTF-8 codec will now encode and decode Unicode surrogates
46 correctly and without raising exceptions for unpaired ones.
47
Neal Norwitz649b7592002-01-01 19:07:13 +000048- file.xreadlines() now raises a ValueError if the file is closed:
49 Previously, an xreadlines object was returned which would raise
50 a ValueError when the xreadlines.next() method was called.
51
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000052- posix.killpg has been added where available.
53
Neal Norwitz0c766a02002-03-27 13:03:09 +000054- sys.exit() inadvertantly allowed more than one argument.
55 An exception will now be raised if more than one argument is used.
56
Tim Petersaf8446f2001-12-21 21:36:50 +000057Extension modules
58
Martin v. Löwis06a83e92002-04-14 10:19:44 +000059- posix.mknod was added.
60
Martin v. Löwis2e64c342002-03-27 18:49:02 +000061- The locale module now exposes the C library's gettext interface.
62
Tim Petersfbf74f22002-03-14 19:06:01 +000063- A security hole ("double free") was found in zlib-1.1.3, a popular
64 third party compression library used by some Python modules. The
65 hole was quickly plugged in zlib-1.1.4, and the Windows build of
66 Python now ships with zlib-1.1.4.
67
Martin v. Löwis688357e2002-04-08 21:28:20 +000068- pwd, grp, and resource return enhanced tuples now, with symbolic
69 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000070
Martin v. Löwis99866332002-03-01 10:27:01 +000071- array.array is now a type object. A new format character
72 'u' indicates Py_UNICODE arrays. For those, .tounicode and
73 .fromunicode methods are available. Arrays now support __iadd__
74 and __imul__.
75
Neal Norwitze790eae2002-01-01 21:14:12 +000076- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000077 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
78 is called.
79
Tim Petersaf8446f2001-12-21 21:36:50 +000080Library
81
Marc-André Lemburg4179a012002-04-05 12:15:05 +000082- The UTF-16, -LE and -BE now raise a NotImplementedError
83 for all calls to .readline(). Previously, they used to just
84 produce garbage or fail with an encoding error -- UTF-16 is
85 a 2-byte encoding and the C lib's line reading APIs don't
86 work well with these.
87
Martin v. Löwis5c137c22002-03-18 12:44:08 +000088- compileall now supports quiet operation.
89
Martin v. Löwis587c98c2002-03-17 18:37:22 +000090- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
91 connections.
92
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +000093- socket module: the SSL support was broken out of the main
94 _socket module C helper and placed into a new _ssl helper
95 which now gets imported by socket.py if available and working.
96
Marc-André Lemburg37aa5802002-02-10 21:42:47 +000097- encodings package: added aliases for all supported IANA character
98 sets
99
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000100- ftplib: to safeguard the user's privacy, anonymous login will use
101 "anonymous@" as default password, rather than the real user and host
102 name.
103
Fred Drake36736122002-01-10 13:50:31 +0000104- webbrowser: tightened up the command passed to os.system() so that
105 arbitrary shell code can't be executed because a bogus URL was
106 passed in.
107
Tim Peters11bd9942002-02-01 00:52:29 +0000108- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000109 gettext.find an optional all argument. Translations will now fallback
110 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000111
Martin v. Löwis9668b932002-01-12 11:27:42 +0000112- distutils bdist commands now offer a --skip-build option.
113
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000114- warnings.warn now accepts a Warning instance as first argument.
115
Fred Drakefed7e852002-04-04 19:36:15 +0000116- The xml.sax.expatreader.ExpatParser class will no longer create
117 circular references by using itself as the locator that gets passed
118 to the content handler implementation. [SF bug #535474]
119
Tim Petersaf8446f2001-12-21 21:36:50 +0000120Tools/Demos
121
Marc-André Lemburg46260092002-04-04 16:17:11 +0000122- freeze.py now produces binaries which can import shared modules,
123 unlike before when this failed due to missing symbol exports in
124 the generated binary.
125
Tim Petersaf8446f2001-12-21 21:36:50 +0000126Build
127
Martin v. Löwis1142de32002-03-29 16:28:31 +0000128- On Unix, a shared libpython2.3.so can be created with --enable-shared.
129
Tim Peters8deda702002-03-30 10:06:07 +0000130- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
131 preprocessor symbols were eliminated. The internal decisions they
132 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000133
Tim Petersaf8446f2001-12-21 21:36:50 +0000134C API
135
Neil Schemenauer9344b142002-04-12 23:00:08 +0000136- The type of tp_free has been changed from "void (*)(PyObject *)" to
137 "void (*)(void *)".
138
139- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
140
Guido van Rossum0986d822002-04-08 01:38:42 +0000141- A type can now inherit its metatype from its base type. Previously,
142 when PyType_Ready() was called, if ob_type was found to be NULL, it
143 was always set to &PyType_Type; now it is set to base->ob_type,
144 where base is tp_base, defaulting to &PyObject_Type.
145
146- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
147
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000148- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
149 functions will be allocated using pymalloc if it is enabled. These
150 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
151 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
152 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
153 PyCore_* family of APIs have been removed.
154
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000155- The "u#" parser marker will now pass through Unicode object as-is
156 without going through the buffer API.
157
Martin v. Löwis7198a522002-01-01 19:59:11 +0000158- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
159
Tim Peters10a3bb52001-12-25 19:07:38 +0000160- An old #define of ANY as void has been removed from pyport.h. This
161 hasn't been used since Python's pre-ANSI days, and the #define has
162 been marked as obsolete since then. SF bug 495548 says it created
163 conflicts with other packages, so keeping it around wasn't harmless.
164
Tim Petersaf8446f2001-12-21 21:36:50 +0000165- Because Python's magic number scheme broke on January 1st, we decided
166 to stop Python development. Thanks for all the fish!
167
Tim Petersfb05db22002-03-11 00:24:00 +0000168- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000169 scheme to a new one. See Python/import.c for details.
170
Tim Petersaf8446f2001-12-21 21:36:50 +0000171New platforms
172
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000173- GNU/Hurd is now supported.
174
Tim Petersaf8446f2001-12-21 21:36:50 +0000175Tests
176
177Windows
178
Guido van Rossum181e41a2002-04-06 00:23:25 +0000179- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
180
Tim Peters33187922002-04-04 20:02:04 +0000181- The installer now installs Start menu shortcuts under (the local
182 equivalent of) "All Users" when doing an Admin install.
183
Tim Petersfb05db22002-03-11 00:24:00 +0000184- file.truncate([newsize]) now works on Windows for all newsize values.
185 It used to fail if newsize didn't fit in 32 bits, reflecting a
186 limitation of MS _chsize (which is no longer used).
187
Tim Petersab034fa2002-02-01 11:27:43 +0000188- os.waitpid() is now implemented for Windows, and can be used to block
189 until a specified process exits. This is similar to, but not exactly
190 the same as, os.waitpid() on POSIX systems. If you're waiting for
191 a specific process whose pid was obtained from one of the spawn()
192 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000193 See the docs for details. The docs were changed to clarify that
194 spawn functions return, and waitpid requires, a process handle on
195 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000196
Tim Peters11bd9942002-02-01 00:52:29 +0000197- New tempfile.TemporaryFile implementation for Windows: this doesn't
198 need a TemproraryFileWrapper wrapper anymore, and should be immune
199 to a nasty problem: before 2.3, if you got a temp file on Windows, it
200 got wrapped in an object whose close() method first closed the
201 underlying file, then deleted the file. This usually worked fine.
202 However, the spawn family of functions on Windows create (at a low C
203 level) the same set of open files in the spawned process Q as were
204 open in the spawning process P. If a temp file f was among them, then
205 doing f.close() in P first closed P's C-level file handle on f, but Q's
206 C-level file handle on f remained open, so the attempt in P to delete f
207 blew up with a "Permission denied" error (Windows doesn't allow
208 deleting open files). This was surprising, subtle, and difficult to
209 work around.
210
211- The os module now exports all the symbolic constants usable with the
212 low-level os.open() on Windows: the new constants in 2.3 are
213 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
214 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
215 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
216 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
217 (so specify both if you want both; note that neither is useful unless
218 specified with O_CREAT too).
219
Tim Petersaf8446f2001-12-21 21:36:50 +0000220Mac
221
222
Tim Peters909c0912001-12-14 23:16:18 +0000223What's New in Python 2.2 final?
224Release date: 21-Dec-2001
225===============================
226
227Type/class unification and new-style classes
228
Barry Warsaw52acb492001-12-21 20:04:22 +0000229- pickle.py, cPickle: allow pickling instances of new-style classes
230 with a custom metaclass.
231
Tim Peters909c0912001-12-14 23:16:18 +0000232Core and builtins
233
Barry Warsaw52acb492001-12-21 20:04:22 +0000234- weakref proxy object: when comparing, unwrap both arguments if both
235 are proxies.
236
Tim Peters909c0912001-12-14 23:16:18 +0000237Extension modules
238
Barry Warsaw52acb492001-12-21 20:04:22 +0000239- binascii.b2a_base64(): fix a potential buffer overrun when encoding
240 very short strings.
241
242- cPickle: the obscure "fast" mode was suspected of causing stack
243 overflows on the Mac. Hopefully fixed this by setting the recursion
244 limit much smaller. If the limit is too low (it only affects
245 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
246 when compiling cPickle.c (or in pyconfig.h).
247
Tim Peters909c0912001-12-14 23:16:18 +0000248Library
249
Barry Warsaw52acb492001-12-21 20:04:22 +0000250- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
251 close or delete time).
252
253- rfc822.py: fixed a bug where the address '<>' was converted to None
254 instead of an empty string (also fixes the email.Utils module).
255
256- xmlrpclib.py: version 1.0.0; uses precision for doubles.
257
258- test suite: the pickle and cPickle tests were not executing any code
259 when run from the standard regresssion test.
260
Tim Peters909c0912001-12-14 23:16:18 +0000261Tools/Demos
262
263Build
264
265C API
266
267New platforms
268
269Tests
270
271Windows
272
Barry Warsaw52acb492001-12-21 20:04:22 +0000273- distutils package: fixed broken Windows installers (bdist_wininst).
274
275- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
276 instances are deleted at process exit time.
277
278- socket.py: prevent mysterious warnings when socket instances are
279 deleted at process exit time.
280
281- posixmodule.c: fix a Windows crash with stat() of a filename ending
282 in backslash.
283
Tim Peters909c0912001-12-14 23:16:18 +0000284Mac
285
Barry Warsaw52acb492001-12-21 20:04:22 +0000286- The Carbon toolbox modules have been upgraded to Universal Headers
287 3.4, and experimental CoreGraphics and CarbonEvents modules have
288 been added. All only for framework-enabled MacOSX.
289
Tim Peters909c0912001-12-14 23:16:18 +0000290
Tim Peters6272dfd2001-12-13 19:34:00 +0000291What's New in Python 2.2c1?
292Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000293===========================
294
295Type/class unification and new-style classes
296
Barry Warsaw06557452001-12-14 20:47:12 +0000297- Guido's tutorial introduction to the new type/class features has
298 been extensively updated. See
299
300 http://www.python.org/2.2/descrintro.html
301
302 That remains the primary documentation in this area.
303
Guido van Rossum33bab012001-12-05 22:45:48 +0000304- Fixed a leak: instance variables declared with __slots__ were never
305 deleted!
306
Guido van Rossum4b800852001-12-03 00:54:52 +0000307- The "delete attribute" method of descriptor objects is called
308 __delete__, not __del__. In previous releases, it was mistakenly
309 called __del__, which created an unfortunate overloading condition
310 with finalizers. (The "get attribute" and "set attribute" methods
311 are still called __get__ and __set__, respectively.)
312
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000313- Some subtle issues with the super built-in were fixed:
314
315 (a) When super itself is subclassed, its __get__ method would still
316 return an instance of the base class (i.e., of super).
317
318 (b) super(C, C()).__class__ would return C rather than super. This
319 is confusing. To fix this, I decided to change the semantics of
320 super so that it only applies to code attributes, not to data
321 attributes. After all, overriding data attributes is not
322 supported anyway.
323
324 (c) The __get__ method didn't check whether the argument was an
325 instance of the type used in creation of the super instance.
326
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000327- Previously, hash() of an instance of a subclass of a mutable type
328 (list or dictionary) would return some value, rather than raising
329 TypeError. This has been fixed. Also, directly calling
330 dict.__hash__ and list.__hash__ now raises the same TypeError
331 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000332
Guido van Rossumd331cb52001-12-05 19:46:42 +0000333- New-style objects now support deleting their __dict__. This is for
334 all intents and purposes equivalent to assigning a brand new empty
335 dictionary, but saves space if the object is not used further.
336
Tim Petersb3c9af12001-11-17 00:21:57 +0000337Core and builtins
338
Tim Peters3caca232001-12-06 06:23:26 +0000339- -Qnew now works as documented in PEP 238: when -Qnew is passed on
340 the command line, all occurrences of "/" use true division instead
341 of classic division. See the PEP for details. Note that "all"
342 means all instances in library and 3rd-party modules, as well as in
343 your own code. As the PEP says, -Qnew is intended for use only in
344 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000345 Note that test_coercion.py in the standard Python test suite fails
346 under -Qnew; this is expected, and won't be repaired until true
347 division becomes the default (in the meantime, test_coercion is
348 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000349
Fred Drake6c01e252001-12-14 17:08:12 +0000350- complex() now only allows the first argument to be a string
351 argument, and raises TypeError if either the second arg is a string
352 or if the second arg is specified when the first is a string.
353
Tim Petersb3c9af12001-11-17 00:21:57 +0000354Extension modules
355
Martin v. Löwis560da622001-11-24 09:24:51 +0000356- gc.get_referents was renamed to gc.get_referrers.
357
Tim Petersb3c9af12001-11-17 00:21:57 +0000358Library
359
Tim Peters25059d32001-12-07 20:35:43 +0000360- Functions in the os.spawn() family now release the global interpreter
361 lock around calling the platform spawn. They should always have done
362 this, but did not before 2.2c1. Multithreaded programs calling
363 an os.spawn function with P_WAIT will no longer block all Python threads
364 until the spawned program completes. It's possible that some programs
365 relies on blocking, although more likely by accident than by design.
366
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000367- webbrowser defaults to netscape.exe on OS/2 now.
368
Martin v. Löwis652e1912001-11-25 14:50:56 +0000369- Tix.ResizeHandle exposes detach_widget, hide, and show.
370
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000371- The charset alias windows_1252 has been added.
372
Barry Warsaw06557452001-12-14 20:47:12 +0000373- types.StringTypes is a tuple containing the defined string types;
374 usually this will be (str, unicode), but if Python was compiled
375 without Unicode support it will be just (str,).
376
377- The pulldom and minidom modules were synchronized to PyXML.
378
Tim Petersb3c9af12001-11-17 00:21:57 +0000379Tools/Demos
380
Barry Warsaw06557452001-12-14 20:47:12 +0000381- A new script called Tools/scripts/google.py was added, which fires
382 off a search on Google.
383
Tim Petersb3c9af12001-11-17 00:21:57 +0000384Build
385
Barry Warsaw06557452001-12-14 20:47:12 +0000386- Note that release builds of Python should arrange to define the
387 preprocessor symbol NDEBUG on the command line (or equivalent).
388 In the 2.2 pre-release series we tried to define this by magic in
389 Python.h instead, but it proved to cause problems for extension
390 authors. The Unix, Windows and Mac builds now all define NDEBUG in
391 release builds via cmdline (or equivalent) instead. Ports to
392 other platforms should do likewise.
393
Jack Jansen1999ef42001-12-06 21:47:20 +0000394- It is no longer necessary to use --with-suffix when building on a
395 case-insensitive file system (such as Mac OS X HFS+). In the build
396 directory an extension is used, but not in the installed python.
397
Tim Petersb3c9af12001-11-17 00:21:57 +0000398C API
399
Tim Petersf582b822001-12-11 18:51:08 +0000400- New function PyDict_MergeFromSeq2() exposes the builtin dict
401 constructor's logic for updating a dictionary from an iterable object
402 producing key-value pairs.
403
Tim Peterscffed4b2001-11-29 03:26:37 +0000404- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000405 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000406 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
407 dump core in some bad cases. This has been repaired. As a result,
408 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
409 previously went unchallenged.
410
Tim Petersb3c9af12001-11-17 00:21:57 +0000411New platforms
412
413Tests
414
415Windows
416
417Mac
418
Jack Jansenffa260f2001-12-06 21:14:00 +0000419- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
420 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000421
Barry Warsaw06557452001-12-14 20:47:12 +0000422- Changed logic for finding python home in Mac OS X framework Pythons.
423 Now sys.executable points to the executable again, in stead of to
424 the shared library. The latter is used only for locating the python
425 home.
426
427
Tim Peters84362bc2001-10-19 17:55:30 +0000428What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000429Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000430===========================
431
432Type/class unification and new-style classes
433
Guido van Rossum3d27df02001-11-15 20:27:54 +0000434- Multiple inheritance mixing new-style and classic classes in the
435 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000436
437 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000438 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000439
440 The MRO (method resolution order) for each base class is respected
441 according to its kind, but the MRO for the derived class is computed
442 using new-style MRO rules if any base clase is a new-style class.
443 This needs to be documented.
444
Tim Petersa427a2b2001-10-29 22:25:45 +0000445- The new builtin dictionary() constructor, and dictionary type, have
446 been renamed to dict. This reflects a decade of common usage.
447
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000448- dict() now accepts an iterable object producing 2-sequences. For
449 example, dict(d.items()) == d for any dictionary d. The argument,
450 and the elements of the argument, can be any iterable objects.
451
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000452- New-style classes can now have a __del__ method, which is called
453 when the instance is deleted (just like for classic classes).
454
Guido van Rossum12d955c2001-10-26 14:56:06 +0000455- Assignment to object.__dict__ is now possible, for objects that are
456 instances of new-style classes that have a __dict__ (unless the base
457 class forbids it).
458
Guido van Rossumc8e56452001-10-22 00:43:43 +0000459- Methods of built-in types now properly check for keyword arguments
460 (formerly these were silently ignored). The only built-in methods
461 that take keyword arguments are __call__, __init__ and __new__.
462
Guido van Rossum86443212001-10-27 22:28:54 +0000463- The socket function has been converted to a type; see below.
464
Tim Peters84362bc2001-10-19 17:55:30 +0000465Core and builtins
466
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000467- Assignment to __debug__ raises SyntaxError at compile-time. This
468 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000469 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000470
Guido van Rossum12d955c2001-10-26 14:56:06 +0000471- Clarified the error messages for unsupported operands to an operator
472 (like 1 + '').
473
Tim Peters84362bc2001-10-19 17:55:30 +0000474Extension modules
475
Tim Peters5ebfd362001-11-13 23:11:19 +0000476- mmap has a new keyword argument, "access", allowing a uniform way for
477 both Windows and Unix users to create read-only, write-through and
478 copy-on-write memory mappings. This was previously possible only on
479 Unix. A new keyword argument was required to support this in a
480 uniform way because the mmap() signuatures had diverged across
481 platforms. Thanks to Jay T Miller for repairing this!
482
Tim Peters169ded02001-11-03 19:57:21 +0000483- By default, the gc.garbage list now contains only those instances in
484 unreachable cycles that have __del__ methods; in 2.1 it contained all
485 instances in unreachable cycles. "Instances" here has been generalized
486 to include instances of both new-style and old-style classes.
487
Guido van Rossum12d955c2001-10-26 14:56:06 +0000488- The socket module defines a new method for socket objects,
489 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000490 send() until all data has been sent. Also, the socket function has
491 been converted to a subclassable type, like list and tuple (etc.)
492 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000493
494- Various bugfixes to the curses module. There is now a test suite
495 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000496
Guido van Rossum692adf12001-10-30 03:03:03 +0000497- binascii.b2a_base64 no longer places an arbitrary restriction of 57
498 bytes on its input.
499
Tim Peters84362bc2001-10-19 17:55:30 +0000500Library
501
Tim Peters5ebfd362001-11-13 23:11:19 +0000502- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000503 convenience function.
504
Tim Peters75335872001-11-03 19:35:43 +0000505- Symbolic group names in regular expressions must be unique. For
506 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
507 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000508 Python 2.2 detects this error at regexp compilation time;
509 previously, the error went undetected, and results were
510 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
511 pattern.subn() methods have been rewritten in C. Also, an
512 experimental function/method finditer() has been added, which works
513 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000514
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000515- Tix exposes more commands through the classes DirSelectBox,
516 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
517 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
518 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
519
Tim Peters98791af2001-10-23 01:59:54 +0000520- Traceback objects are now scanned by cyclic garbage collection, so
521 cycles created by casual use of sys.exc_info() no longer cause
522 permanent memory leaks (provided garbage collection is enabled).
523
Guido van Rossum49192142001-10-24 20:51:44 +0000524- os.extsep -- a new variable needed by the RISCOS support. It is the
525 separator used by extensions, and is '.' on all platforms except
526 RISCOS, where it is '/'. There is no need to use this variable
527 unless you have a masochistic desire to port your code to RISCOS.
528
Barry Warsaw012852b2001-11-16 16:17:27 +0000529- mimetypes.py has optional support for non-standard, but commonly
530 found types. guess_type() and guess_extension() now accept an
531 optional `strict' flag, defaulting to true, which controls whether
532 recognize non-standard types or not. A few non-standard types we
533 know about have been added. Also, when run as a script, there are
534 new -l and -e options.
535
536- statcache is now deprecated.
537
538- email.Utils.formatdate() now produces the preferred RFC 2822 style
539 dates with numeric timezones (it used to produce obsolete dates
540 hard coded to "GMT" timezone). An optional `localtime' flag is
541 added to produce dates in the local timezone, with daylight savings
542 time properly taken into account.
543
544- In pickle and cPickle, instead of masking errors in load() by
545 transforming them into SystemError, we let the original exception
546 propagate out. Also, implement support for __safe_for_unpickling__
547 in pickle, as it already was supported in cPickle.
548
Tim Peters84362bc2001-10-19 17:55:30 +0000549Tools/Demos
550
551Build
552
Barry Warsaw012852b2001-11-16 16:17:27 +0000553- The dbm module is built using libdb1 if available. The bsddb module
554 is built with libdb3 if available.
555
556- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
557
Tim Peters84362bc2001-10-19 17:55:30 +0000558C API
559
Tim Peters1fc240e2001-10-26 05:06:50 +0000560- New function PySequence_Fast_GET_SIZE() returns the size of a non-
561 NULL result from PySequence_Fast(), more quickly than calling
562 PySequence_Size().
563
Barry Warsaw012852b2001-11-16 16:17:27 +0000564- New argument unpacking function PyArg_UnpackTuple() added.
565
566- New functions PyObject_CallFunctionObjArgs() and
567 PyObject_CallMethodObjArgs() have been added to make it more
568 convenient and efficient to call functions and methods from C.
569
570- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
571 possible that this will propagate errors it didn't before.
572
573- New function PyObject_CheckReadBuffer(), which returns true if its
574 argument supports the single-segment readable buffer interface.
575
Tim Peters84362bc2001-10-19 17:55:30 +0000576New platforms
577
Guido van Rossum86443212001-10-27 22:28:54 +0000578- We've finally confirmed that this release builds on HP-UX 11.00,
579 *with* threads, and passes the test suite.
580
Tim Peters7a33d8b2001-11-05 02:51:07 +0000581- Thanks to a series of patches from Michael Muller, Python may build
582 again under OS/2 Visual Age C++.
583
Guido van Rossum49192142001-10-24 20:51:44 +0000584- Updated RISCOS port by Dietmar Schwertberger.
585
Tim Peters84362bc2001-10-19 17:55:30 +0000586Tests
587
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000588- Added a test script for the curses module. It isn't run automatically;
589 regrtest.py must be run with '-u curses' to enable it.
590
Tim Peters84362bc2001-10-19 17:55:30 +0000591Windows
592
Barry Warsaw012852b2001-11-16 16:17:27 +0000593Mac
594
595- PythonScript has been moved to unsupported and is slated to be
596 removed completely in the next release.
597
598- It should now be possible to build applets that work on both OS9 and
599 OSX.
600
601- The core is now linked with CoreServices not Carbon; as a side
602 result, default 8bit encoding on OSX is now ASCII.
603
604- Python should now build on OSX 10.1.1
605
Tim Peters84362bc2001-10-19 17:55:30 +0000606
Tim Petersabf925f2001-09-28 21:53:42 +0000607What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000608Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000609===========================
610
611Type/class unification and new-style classes
612
Guido van Rossum687ae002001-10-15 22:03:32 +0000613- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000614 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000615 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000616 remains: the __dict__ of a new-style class is a read-only proxy; you
617 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000618 __defined__ attribute of new-style types no longer exists, for lack
619 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000620 future a __cache__ may be resurrected with a similar function, if I
621 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000622
Tim Peters1c9ca872001-10-04 06:43:12 +0000623- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
624 always returned None, even when there was a class docstring).
625
626- doctest now finds and runs docstrings attached to new-style classes,
627 class methods, static methods, and properties.
628
Guido van Rossum9074ef62001-10-16 21:34:49 +0000629Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000630
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000631- A very subtle syntactical pitfall in list comprehensions was fixed.
632 For example: [a+b for a in 'abc', for b in 'def']. The comma in
633 this example is a mistake. Previously, this would silently let 'a'
634 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
635 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
636 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
637 Note that [a for a in <singleton>] is a convoluted way to say
638 [<singleton>] anyway, so it's not like any expressiveness is lost.
639
Guido van Rossum9074ef62001-10-16 21:34:49 +0000640- getattr(obj, name, default) now only catches AttributeError, as
641 documented, rather than returning the default value for all
642 exceptions (which could mask bugs in a __getattr__ hook, for
643 example).
644
Fred Drakecb7a6b52001-10-22 18:41:51 +0000645- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000646 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000647 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000648 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000649
Guido van Rossum1c486092001-10-19 02:05:35 +0000650- unicode(obj) now behaves more like str(obj), accepting arbitrary
651 objects, and calling a __unicode__ method if it exists.
652 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000653 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000654
Barry Warsawf6fb1712001-10-19 05:35:40 +0000655- isinstance() now allows any object as the first argument and a
656 class, a type or something with a __bases__ tuple attribute for the
657 second argument. The second argument may also be a tuple of a
658 class, type, or something with __bases__, in which case isinstance()
659 will return true if the first argument is an instance of any of the
660 things contained in the second argument tuple. E.g.
661
662 isinstance(x, (A, B))
663
664 returns true if x is an instance of A or B.
665
Guido van Rossum9074ef62001-10-16 21:34:49 +0000666Extension modules
667
668- thread.start_new_thread() now returns the thread ID (previously None).
669
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000670- binascii has now two quopri support functions, a2b_qp and b2a_qp.
671
Guido van Rossumc524d952001-10-19 01:31:59 +0000672- readline now supports setting the startup_hook and the
673 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000674
Guido van Rossumc524d952001-10-19 01:31:59 +0000675- os and posix supports chroot(), setgroups() and unsetenv() where
676 available. The stat(), fstat(), statvfs() and fstatvfs() functions
677 now return "pseudo-sequences" -- the various fields can now be
678 accessed as attributes (e.g. os.stat("/").st_mtime) but for
679 backwards compatibility they also behave as a fixed-length sequence.
680 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000681 attributes.
682
683- time: localtime(), gmtime() and strptime() now return a
684 pseudo-sequence similar to the os.stat() return value, with
685 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000686
Guido van Rossum9074ef62001-10-16 21:34:49 +0000687- Decompression objects in the zlib module now accept an optional
688 second parameter to decompress() that specifies the maximum amount
689 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000690
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000691- optional SSL support in the socket module now exports OpenSSL
692 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
693 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000694 automatically seed its PRNG. Also, the keyfile and certfile
695 arguments to socket.ssl() are now optional.
696
697- posixmodule (and by extension, the os module on POSIX platforms) now
698 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000699
Guido van Rossum9074ef62001-10-16 21:34:49 +0000700Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000701
Tim Peters7402f792001-10-02 03:53:41 +0000702- doctest now excludes functions and classes not defined by the module
703 being tested, thanks to Tim Hochberg.
704
Fred Drakecb7a6b52001-10-22 18:41:51 +0000705- HotShot, a new profiler implemented using a C-based callback, has
706 been added. This substantially reduces the overhead of profiling,
707 but it is still quite preliminary. Support modules and
708 documentation will be added in upcoming releases (before 2.2 final).
709
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000710- profile now produces correct output in situations where an exception
711 raised in Python is cleared by C code (e.g. hasattr()). This used
712 to cause wrong output, including spurious claims of recursive
713 functions and attribution of time spent to the wrong function.
714
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000715 The code and documentation for the derived OldProfile and HotProfile
716 profiling classes was removed. The code hasn't worked for years (if
717 you tried to use them, they raised exceptions). OldProfile
718 intended to reproduce the behavior of the profiler Python used more
719 than 7 years ago, and isn't interesting anymore. HotProfile intended
720 to provide a faster profiler (but producing less information), and
721 that's a worthy goal we intend to meet via a different approach (but
722 without losing information).
723
Tim Peterscce092d2001-10-09 05:31:56 +0000724- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000725 a much better system-specific calibration constant. The constant can
726 now be specified in an instance constructor, or as a Profile class or
727 instance variable, instead of by editing profile.py's source code.
728 Calibration must still be done manually (see the docs for the profile
729 module).
730
731 Note that Profile.calibrate() must be overriden by subclasses.
732 Improving the accuracy required exploiting detailed knowledge of
733 profiler internals; the earlier method abstracted away the details
734 and measured a simplified model instead, but consequently computed
735 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000736
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000737- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000738 which indicates whether output is intended for the header 'Q'
739 encoding.
740
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000741- The SocketServer.ThreadingMixIn class now closes the request after
742 finish_request() returns. (Not when it errors out though.)
743
Barry Warsawf6fb1712001-10-19 05:35:40 +0000744- The nntplib module's NNTP.body() method has grown a `file' argument
745 to allow saving the message body to a file.
746
747- The email package has added a class email.Parser.HeaderParser which
748 only parses headers and does not recurse into the message's body.
749 Also, the module/class MIMEAudio has been added for representing
750 audio data (contributed by Anthony Baxter).
751
752- ftplib should be able to handle files > 2GB.
753
754- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
755 ON, and OFF.
756
Fred Drakecb7a6b52001-10-22 18:41:51 +0000757- xml.dom.minidom NodeList objects now support the length attribute
758 and item() method as required by the DOM specifications.
759
Guido van Rossumed554f62001-10-02 23:15:37 +0000760Tools/Demos
761
762- Demo/dns was removed. It no longer serves any purpose; a package
763 derived from it is now maintained by Anthony Baxter, see
764 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000765
Barry Warsawf6fb1712001-10-19 05:35:40 +0000766- The freeze tool has been made more robust, and two new options have
767 been added: -X and -E.
768
Tim Petersabf925f2001-09-28 21:53:42 +0000769Build
770
Barry Warsawf6fb1712001-10-19 05:35:40 +0000771- configure will use CXX in LINKCC if CXX is used to build main() and
772 the system requires to link a C++ main using the C++ compiler.
773
Tim Petersabf925f2001-09-28 21:53:42 +0000774C API
775
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000776- The documentation for the tp_compare slot is updated to require that
777 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
778 not correct. This is not yet enforced but will be enforced in
779 Python 2.3; even later, we may use -2 to indicate errors and +2 for
780 "NotImplemented". Right now, -1 should be used for an error return.
781
Tim Petersd38b1c72001-09-30 05:09:37 +0000782- PyLong_AsLongLong() now accepts int (as well as long) arguments.
783 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
784 as long) arguments.
785
Guido van Rossum3c288632001-10-16 21:13:49 +0000786- PyThread_start_new_thread() now returns a long int giving the thread
787 ID, if one can be calculated; it returns -1 for error, 0 if no
788 thread ID is calculated (this is an incompatible change, but only
789 the thread module used this API). This code has only really been
790 tested on Linux and Windows; other platforms please beware (and
791 report any bugs or strange behavior).
792
Guido van Rossum1c486092001-10-19 02:05:35 +0000793- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
794 input.
795
Tim Petersabf925f2001-09-28 21:53:42 +0000796New platforms
797
798Tests
799
800Windows
801
Tim Peters04cf1d32001-10-09 22:39:40 +0000802- Installer: If you install IDLE, and don't disable file-extension
803 registration, a new "Edit with IDLE" context (right-click) menu entry
804 is created for .py and .pyw files.
805
Tim Peters1ce3cf72001-10-01 17:58:40 +0000806- The signal module now supports SIGBREAK on Windows, thanks to Steven
807 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
808 action remains to call Win32 ExitProcess(). This can be changed via
809 signal.signal(). For example:
810
811 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
812 # (SIGINT) behavior.
813 import signal
814 signal.signal(signal.SIGBREAK,
815 signal.default_int_handler)
816
817 try:
818 while 1:
819 pass
820 except KeyboardInterrupt:
821 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
822 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
823 # program without the possibility for any Python-level cleanup).
824 print "Clean exit"
825
Tim Petersabf925f2001-09-28 21:53:42 +0000826
Tim Petersb07352e2001-09-08 01:25:47 +0000827What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000828Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000829===========================
830
Guido van Rossum808eea72001-09-25 04:15:41 +0000831Type/class unification and new-style classes
832
833- pydoc and inspect are now aware of new-style classes;
834 e.g. help(list) at the interactive prompt now shows proper
835 documentation for all operations on list objects.
836
837- Applications using Jim Fulton's ExtensionClass module can now safely
838 be used with Python 2.2. In particular, Zope 2.4.1 now works with
839 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
840 examples also work again. It is hoped that Gtk and Boost also work
841 with 2.2a4 and beyond. (If you can confirm this, please write
842 webmaster@python.org; if there are still problems, please open a bug
843 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000844
Tim Peters66c1a522001-09-24 21:17:50 +0000845- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
846 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
847 in the constructed property object. fget, fset and fdel weren't
848 discoverable from Python in 2.2a3. __doc__ is new, and allows to
849 associate a docstring with a property.
850
Guido van Rossum808eea72001-09-25 04:15:41 +0000851- Comparison overloading is now more completely implemented. For
852 example, a str subclass instance can properly be compared to a str
853 instance, and it can properly overload comparison. Ditto for most
854 other built-in object types.
855
856- The repr() of new-style classes has changed; instead of <type
857 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
858 *except* for built-in types, which are still rendered as <type
859 'Foo'> (to avoid upsetting existing code that might parse or
860 otherwise rely on repr() of certain type objects).
861
862- The repr() of new-style objects is now always <Foo object at XXX>;
863 previously, it was sometimes <Foo instance at XXX>.
864
865- For new-style classes, what was previously called __getattr__ is now
866 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000867 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000868 one in classic classes is defined which is called only if regular
869 attribute access raises AttributeError; to catch *all* attribute
870 access, you can use __getattribute__ (for new-style classes). If
871 both are defined, __getattribute__ is called first, and if it raises
872 AttributeError, __getattr__ is called.
873
874- The __class__ attribute of new-style objects can be assigned to.
875 The new class must have the same C-level object layout as the old
876 class.
877
878- The builtin file type can be subclassed now. In the usual pattern,
879 "file" is the name of the builtin type, and file() is a new builtin
880 constructor, with the same signature as the builtin open() function.
881 file() is now the preferred way to open a file.
882
883- Previously, __new__ would only see sequential arguments passed to
884 the type in a constructor call; __init__ would see both sequential
885 and keyword arguments. This made no sense whatsoever any more, so
886 now both __new__ and __init__ see all arguments.
887
888- Previously, hash() applied to an instance of a subclass of str or
889 unicode always returned 0. This has been repaired.
890
891- Previously, an operation on an instance of a subclass of an
892 immutable type (int, long, float, complex, tuple, str, unicode),
893 where the subtype didn't override the operation (and so the
894 operation was handled by the builtin type), could return that
895 instance instead a value of the base type. For example, if s was of
896 a str sublass type, s[:] returned s as-is. Now it returns a str
897 with the same value as s.
898
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000899- Provisional support for pickling new-style objects has been added.
900
Guido van Rossum808eea72001-09-25 04:15:41 +0000901Core
902
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000903- file.writelines() now accepts any iterable object producing strings.
904
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000905- PyUnicode_FromEncodedObject() now works very much like
906 PyObject_Str(obj) in that it tries to use __str__/tp_str
907 on the object if the object is not a string or buffer. This
908 makes unicode() behave like str() when applied to non-string/buffer
909 objects.
910
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000911- PyFile_WriteObject now passes Unicode objects to the file's write
912 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000913 of a print statement must support Unicode objects, i.e. they must
914 at least convert them into ASCII strings.
915
Guido van Rossum624c8af2001-09-18 15:21:04 +0000916- Thread scheduling on Solaris should be improved; it is no longer
917 necessary to insert a small sleep at the start of a thread in order
918 to let other runnable threads be scheduled.
919
Tim Petersb07352e2001-09-08 01:25:47 +0000920Library
921
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000922- StringIO.StringIO instances and cStringIO.StringIO instances support
923 read character buffer compatible objects for their .write() methods.
924 These objects are converted to strings and then handled as such
925 by the instances.
926
Barry Warsaw2f600732001-09-24 04:28:10 +0000927- The "email" package has been added. This is basically a port of the
928 mimelib package <http://sf.net/projects/mimelib> with API changes
929 and some implementations updated to use iterators and generators.
930
Tim Peters8a9c2842001-09-22 21:30:22 +0000931- difflib.ndiff() and difflib.Differ.compare() are generators now. This
932 restores the ability of Tools/scripts/ndiff.py to start producing output
933 before the entire comparison is complete.
934
Barry Warsaw58b072d2001-09-22 04:44:21 +0000935- StringIO.StringIO instances and cStringIO.StringIO instances support
936 iteration just like file objects (i.e. their .readline() method is
937 called for each iteration until it returns an empty string).
938
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000939- The codecs module has grown four new helper APIs to access
940 builtin codecs: getencoder(), getdecoder(), getreader(),
941 getwriter().
942
Guido van Rossum624c8af2001-09-18 15:21:04 +0000943- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
944 simplifies writing XML RPC servers.
945
Barry Warsaw647d5e82001-09-28 17:01:02 +0000946- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000947 after interpretation of symbolic links. On non-Unix systems, this
948 is an alias for os.path.abspath().
949
Tim Peters16a77ad2001-09-08 04:00:12 +0000950- operator.indexOf() (PySequence_Index() in the C API) now works with any
951 iterable object.
952
Guido van Rossum624c8af2001-09-18 15:21:04 +0000953- smtplib now supports various authentication and security features of
954 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000955
Guido van Rossum624c8af2001-09-18 15:21:04 +0000956- hmac: a new module implementing keyed hashing for message
957 authentication.
958
959- mimetypes now recognizes more extensions and file types. At the
960 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000961
Guido van Rossum624c8af2001-09-18 15:21:04 +0000962- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000963 Python 2.2 bytecode generation. It has also been promoted from a
964 Tool to a standard library package. (Tools/compiler still exists as
965 a sample driver.)
966
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000967Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000968
Tim Petersb07352e2001-09-08 01:25:47 +0000969Build
970
Guido van Rossum624c8af2001-09-18 15:21:04 +0000971- Large file support (LFS) is now automatic when the platform supports
972 it; no more manual configuration tweaks are needed. On Linux, at
973 least, it's possible to have a system whose C library supports large
974 files but whose kernel doesn't; in this case, large file support is
975 still enabled but doesn't do you any good unless you upgrade your
976 kernel or share your Python executable with another system whose
977 kernel has large file support.
978
979- The configure script now supplies plausible defaults in a
980 cross-compilation environment. This doesn't mean that the supplied
981 values are always correct, or that cross-compilation now works
982 flawlessly -- but it's a first step (and it shuts up most of
983 autoconf's warnings about AC_TRY_RUN).
984
985- The Unix build is now a bit less chatty, courtesy of the parser
986 generator. The build is completely silent (except for errors) when
987 using "make -s", thanks to a -q option to setup.py.
988
Tim Petersb07352e2001-09-08 01:25:47 +0000989C API
990
Guido van Rossum624c8af2001-09-18 15:21:04 +0000991- The "structmember" API now supports some new flag bits to deny read
992 and/or write access to attributes in restricted execution mode.
993
Tim Petersb07352e2001-09-08 01:25:47 +0000994New platforms
995
Guido van Rossum624c8af2001-09-18 15:21:04 +0000996- Compaq's iPAQ handheld, running the "familiar" Linux distribution
997 (http://familiar.handhelds.org).
998
Tim Petersb07352e2001-09-08 01:25:47 +0000999Tests
1000
Tim Peters8a9c2842001-09-22 21:30:22 +00001001- The "classic" standard tests, which work by comparing stdout to
1002 an expected-output file under Lib/test/output/, no longer stop at
1003 the first mismatch. Instead the test is run to completion, and a
1004 variant of ndiff-style comparison is used to report all differences.
1005 This is much easier to understand than the previous style of reporting.
1006
1007- The unittest-based standard tests now use regrtest's test_main()
1008 convention, instead of running as a side-effect of merely being
1009 imported. This allows these tests to be run in more natural and
1010 flexible ways as unittests, outside the regrtest framework.
1011
1012- regrtest.py is much better integrated with unittest and doctest now,
1013 especially in regard to reporting errors.
1014
Tim Petersb07352e2001-09-08 01:25:47 +00001015Windows
1016
Guido van Rossum624c8af2001-09-18 15:21:04 +00001017- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001018 that support it (NTFS under Windows 2000). See "What's New in
1019 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001020
Tim Petersb07352e2001-09-08 01:25:47 +00001021
Tim Petersedc99312001-08-22 21:36:50 +00001022What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001023Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001024===========================
1025
1026Core
1027
Tim Peters9fffa3e2001-09-04 05:14:19 +00001028- Conversion of long to float now raises OverflowError if the long is too
1029 big to represent as a C double.
1030
Tim Peters32f453e2001-09-03 08:35:41 +00001031- The 3-argument builtin pow() no longer allows a third non-None argument
1032 if either of the first two arguments is a float, or if both are of
1033 integer types and the second argument is negative (in which latter case
1034 the arguments are converted to float, so this is really the same
1035 restriction).
1036
Tim Peters5d2b77c2001-09-03 05:47:38 +00001037- The builtin dir() now returns more information, and sometimes much
1038 more, generally naming all attributes of an object, and all attributes
1039 reachable from the object via its class, and from its class's base
1040 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1041 an empty list. In 2.2a3,
1042
1043 >>> dir([])
1044 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1045 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1046 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1047 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1048 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1049 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1050 'reverse', 'sort']
1051
1052 dir(module) continues to return only the module's attributes, though.
1053
Tim Petersbdee63f2001-09-02 03:40:59 +00001054- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001055 than raising OverflowError. This is a partial implementation of PEP
1056 237. You can use -Wdefault::OverflowWarning to enable a warning for
1057 this situation, and -Werror::OverflowWarning to revert to the old
1058 OverflowError exception.
1059
Guido van Rossum61c345f2001-09-04 03:26:15 +00001060- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001061 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001062 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1063 -Qold, meaning the / operator has its classic meaning and no
1064 warnings are issued. Using -Qwarn issues a run-time warning about
1065 all uses of classic division for int and long arguments; -Qwarnall
1066 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001067 (for use with fixdiv.py).
1068 [Note: the remainder of this paragraph (preserved below) became
1069 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1070 <obsolete>
1071 Using -Qnew is questionable; it turns on new division by default, but
1072 only in the __main__ module. You can usefully combine -Qwarn or
1073 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1074 warns about classic division everywhere else.
1075 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001076
Tim Petersbdee63f2001-09-02 03:40:59 +00001077- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001078 long, float, str, unicode, and tuple. (The types complex, list and
1079 dictionary can also be subclassed; this was introduced earlier.)
1080 Note that restrictions apply when subclassing immutable built-in
1081 types: you can only affect the value of the instance by overloading
1082 __new__. You can add mutable attributes, and the subclass instances
1083 will have a __dict__ attribute, but you cannot change the "value"
1084 (as implemented by the base class) of an immutable subclass instance
1085 once it is created.
1086
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001087- The dictionary constructor now takes an optional argument, a
1088 mapping-like object, and initializes the dictionary from its
1089 (key, value) pairs.
1090
Tim Petersbdee63f2001-09-02 03:40:59 +00001091- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001092 "cooperative super calls" in a multiple inheritance setting. For an
1093 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1094
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001095- A new built-in type, property, has been added. This enables the
1096 creation of "properties". These are attributes implemented by
1097 getter and setter functions (or only one of these for read-only or
1098 write-only attributes), without the need to override __getattr__.
1099 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001100
Tim Petersbdee63f2001-09-02 03:40:59 +00001101- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001102 liberalized, to allow leading zeroes. Examples of literals now
1103 legal that were SyntaxErrors before:
1104
1105 00.0 0e3 0100j 07.5 00000000000000000008.
1106
Tim Petersbdee63f2001-09-02 03:40:59 +00001107- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001108 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1109
Tim Petersedc99312001-08-22 21:36:50 +00001110Library
1111
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001112- telnetlib includes symbolic names for the options, and support for
1113 setting an option negotiation callback.
1114
Tim Petersa40c7932001-09-05 22:36:56 +00001115- The new C standard no longer requires that math libraries set errno to
1116 ERANGE on overflow. For platform libraries that exploit this new
1117 freedom, Python's overflow-checking was wholly broken. A new overflow-
1118 checking scheme attempts to repair that, but may not be reliable on all
1119 platforms (C doesn't seem to provide anything both useful and portable
1120 in this area anymore).
1121
Martin v. Löwis44f86962001-09-05 13:44:54 +00001122- Asynchronous timeout actions are available through the new class
1123 threading.Timer.
1124
Tim Peters78526162001-09-05 00:53:45 +00001125- math.log and math.log10 now return sensible results for even huge
1126 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1127
Tim Petersbdee63f2001-09-02 03:40:59 +00001128- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001129 currently held. See the docs for the imp module.
1130
Tim Petersbdee63f2001-09-02 03:40:59 +00001131- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001132 dumps containing ints written on platforms where Python ints are 8 bytes.
1133 When read on a box where Python ints are 4 bytes, such values are
1134 converted to Python longs.
1135
Tim Petersbdee63f2001-09-02 03:40:59 +00001136- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001137 code objects is no longer allowed. This plugs a security hole.
1138
Steve Purcell6091cd62001-09-06 16:05:17 +00001139- unittest.TestResult instances no longer store references to tracebacks
1140 generated by test failures. This prevents unexpected dangling references
1141 to objects that should be garbage collected between tests.
1142
Tim Petersedc99312001-08-22 21:36:50 +00001143Tools
1144
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001145- Tools/scripts/fixdiv.py has been added which can be used to fix
1146 division operators as per PEP 238.
1147
Tim Petersedc99312001-08-22 21:36:50 +00001148Build
1149
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001150- If you are an adventurous person using Mac OS X you may want to look at
1151 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1152 application, which can be used for experimenting with Carbon or Cocoa.
1153 Discussion of this on pythonmac-sig, please.
1154
Tim Peters7eea37e2001-09-04 22:08:56 +00001155C API
1156
1157- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001158
Tim Peters9fffa3e2001-09-04 05:14:19 +00001159- Note that PyLong_AsDouble can fail! This has always been true, but no
1160 callers checked for it. It's more likely to fail now, because overflow
1161 errors are properly detected now. The proper way to check:
1162
1163 double x = PyLong_AsDouble(some_long_object);
1164 if (x == -1.0 && PyErr_Occurred()) {
1165 /* The conversion failed. */
1166 }
1167
Tim Petersbdee63f2001-09-02 03:40:59 +00001168- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001169 compile but will not participate in GC. To upgrade an extension
1170 module:
1171
1172 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001173
Neil Schemenauer4042c692001-08-30 15:38:01 +00001174 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1175 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001176
Neil Schemenauer4042c692001-08-30 15:38:01 +00001177 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1178 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001179
Neil Schemenauer4042c692001-08-30 15:38:01 +00001180 - remove PyGC_HEAD_SIZE from object size calculations
1181
1182 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1183
Tim Petersbdee63f2001-09-02 03:40:59 +00001184- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001185 These can be used safely to construct string objects from a
1186 sprintf-style format string (similar to the format string supported
1187 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001188
Tim Petersedc99312001-08-22 21:36:50 +00001189New platforms
1190
Tim Petersb7da0902001-09-02 23:01:43 +00001191- Stephen Hansen contributed patches sufficient to get a clean compile
1192 under Borland C (Windows), but he reports problems running it and ran
1193 out of time to complete the port. Volunteers? Expect a MemoryError
1194 when importing the types module; this is probably shallow, and
1195 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001196
Tim Petersedc99312001-08-22 21:36:50 +00001197Tests
1198
1199Windows
1200
Tim Peters6e13a562001-09-06 00:32:15 +00001201- Large file support is now enabled on Win32 platforms as well as on
1202 Win64. This means that, for example, you can use f.tell() and f.seek()
1203 to manipulate files larger than 2 gigabytes (provided you have enough
1204 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001205 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1206 filesize limit, and large file support makes no difference there.
1207 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1208 NTFS has no practical limit on file size, and files of any size can be
1209 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001210
Tim Petersbdee63f2001-09-02 03:40:59 +00001211- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001212 points to command.com (patch from Brian Quinlan).
1213
Tim Petersedc99312001-08-22 21:36:50 +00001214
Tim Peters20f51a72001-07-21 02:31:40 +00001215What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001216Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001217===========================
1218
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001219Build
1220
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001221- Tim Peters developed a brand new Windows installer using Wise 8.1,
1222 generously donated to us by Wise Solutions.
1223
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001224- configure supports a new option --enable-unicode, with the values
1225 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1226 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001227
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001228- A new configure option --enable-framework builds a Mac OS X framework,
1229 which "make frameworkinstall" will install. This provides a starting
1230 point for more mac-like functionality, join pythonmac-sig@python.org
1231 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001232
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001233- The NeXT platform is no longer supported.
1234
1235- The `new' module is now statically linked.
1236
Tim Peters0afb6092001-08-15 06:06:44 +00001237Tools
1238
1239- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001240 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001241 the module docstring for details.
1242
Tim Peters20f51a72001-07-21 02:31:40 +00001243Tests
1244
Tim Peters5e824c32001-08-12 22:25:01 +00001245- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001246 platforms, allowing to give clearer test result output. regrtest
1247 also has optional --use/-u switch to run normally disabled tests
1248 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001249
Tim Peters20f51a72001-07-21 02:31:40 +00001250- Several new tests in the standard test suite, with special thanks to
1251 Nick Mathewson.
1252
1253Core
1254
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001255- The floor division operator // has been added as outlined in PEP
1256 238. The / operator still provides classic division (and will until
1257 Python 3.0) unless "from __future__ import division" is included, in
1258 which case the / operator will provide true division. The operator
1259 module provides truediv() and floordiv() functions. Augmented
1260 assignment variants are included, as are the equivalent overloadable
1261 methods and C API methods. See the PEP for a full discussion:
1262 <http://python.sf.net/peps/pep-0238.html>
1263
Tim Peters6cd6a822001-08-17 22:11:27 +00001264- Future statements are now effective in simulated interactive shells
1265 (like IDLE). This should "just work" by magic, but read Michael
1266 Hudson's "Future statements in simulated shells" PEP 264 for full
1267 details: <http://python.sf.net/peps/pep-0264.html>.
1268
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001269- The type/class unification (PEP 252-253) was integrated into the
1270 trunk and is not so tentative any more (the exact specification of
1271 some features is still tentative). A lot of work has done on fixing
1272 bugs and adding robustness and features (performance still has to
1273 come a long way).
1274
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001275- Warnings about a mismatch in the Python API during extension import
1276 now use the Python warning framework (which makes it possible to
1277 write filters for these warnings).
1278
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001279- A function's __dict__ (aka func_dict) will now always be a
1280 dictionary. It used to be possible to delete it or set it to None,
1281 but now both actions raise TypeErrors. It is still legal to set it
1282 to a dictionary object. Getting func.__dict__ before any attributes
1283 have been assigned now returns an empty dictionary instead of None.
1284
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001285- A new command line option, -E, was added which disables the use of
1286 all environment variables, or at least those that are specifically
1287 significant to Python. Usually those have a name starting with
1288 "PYTHON". This was used to fix a problem where the tests fail if
1289 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1290 older distribution.
1291
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001292Library
1293
Tim Peters5e824c32001-08-12 22:25:01 +00001294- New class Differ and new functions ndiff() and restore() in difflib.py.
1295 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001296 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001297
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001298- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1299 value using the minimal quoting required for the value; more
1300 reliable than using xml.sax.saxutils.escape() for attribute values.
1301
1302- Readline completion support for cmd.Cmd was added.
1303
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001304- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1305
1306- Added function threading.BoundedSemaphore()
1307
1308- Added Ka-Ping Yee's cgitb.py module.
1309
1310- The `new' module now exposes the CO_xxx flags.
1311
Martin v. Löwis560da622001-11-24 09:24:51 +00001312- The gc module offers the get_referents function.
1313
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001314New platforms
1315
1316C API
1317
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001318- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1319 which provide a cross-platform implementations for the
1320 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1321 the standard sprintf() and vsprintf() C lib APIs, these versions
1322 apply bounds checking on the used buffer which enhances protection
1323 against buffer overruns.
1324
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001325- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001326 and extensions using different Unicode widths is rendered next to
1327 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001328 will result in an ImportError. Unicode extensions writers must make
1329 sure to check the Unicode width compatibility in their extensions by
1330 using at least one of the mangled Unicode APIs in the extension.
1331
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001332- Two new flags METH_NOARGS and METH_O are available in method definition
1333 tables to simplify implementation of methods with no arguments and a
1334 single untyped argument. Calling such methods is more efficient than
1335 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1336 deprecated.
1337
Tim Petersc1731372001-08-04 08:12:36 +00001338Windows
1339
1340- "import module" now compiles module.pyw if it exists and nothing else
1341 relevant is found.
1342
Tim Peters20f51a72001-07-21 02:31:40 +00001343
Guido van Rossum55a78992001-07-17 17:22:32 +00001344What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001345Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001346===========================
1347
1348Core
Tim Petersa814db52001-05-14 07:05:58 +00001349
Tim Peters6d6c1a32001-08-02 04:15:00 +00001350- TENTATIVELY, a large amount of code implementing much of what's
1351 described in PEP 252 (Making Types Look More Like Classes) and PEP
1352 253 (Subtyping Built-in Types) was added. This will be released
1353 with Python 2.2a1. Documentation will be provided separately
1354 through http://www.python.org/2.2/. The purpose of releasing this
1355 with Python 2.2a1 is to test backwards compatibility. It is
1356 possible, though not likely, that a decision is made not to release
1357 this code as part of 2.2 final, if any serious backwards
1358 incompapatibilities are found during alpha testing that cannot be
1359 repaired.
1360
Guido van Rossum55a78992001-07-17 17:22:32 +00001361- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001362 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001363 more 'yield' statements. See PEP 255. Since this adds a new
1364 keyword to the language, this feature must be enabled by including a
1365 future statement: "from __future__ import generators" (see PEP 236).
1366 Generators will become a standard feature in a future release
1367 (probably 2.3). Without this future statement, 'yield' remains an
1368 ordinary identifier, but a warning is issued each time it is used.
1369 (These warnings currently don't conform to the warnings framework of
1370 PEP 230; we intend to fix this in 2.2a2.)
1371
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001372- The UTF-16 codec was modified to be more RFC compliant. It will now
1373 only remove BOM characters at the start of the string and then
1374 only if running in native mode (UTF-16-LE and -BE won't remove a
1375 leading BMO character).
1376
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001377- Strings now have a new method .decode() to complement the already
1378 existing .encode() method. These two methods provide direct access
1379 to the corresponding decoders and encoders of the registered codecs.
1380
1381 To enhance the usability of the .encode() method, the special
1382 casing of Unicode object return values was dropped (Unicode objects
1383 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001384
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001385 Both methods will now return whatever the codec in charge of the
1386 requested encoding returns as object, e.g. Unicode codecs will
1387 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1388 will return u"äöü"). This enables codec writer to create codecs
1389 for various simple to use conversions.
1390
1391 New codecs were added to demonstrate these new features (the .encode()
1392 and .decode() columns indicate the type of the returned objects):
1393
1394 Name | .encode() | .decode() | Description
1395 ----------------------------------------------------------------------
1396 uu | string | string | UU codec (e.g. for email)
1397 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001398 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001399 zlib | string | string | zlib compression
1400 hex | string | string | 2-byte hex codec
1401 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1402
Mark Hammond2a0af792001-05-14 03:09:36 +00001403- Some operating systems now support the concept of a default Unicode
1404 encoding for file system operations. Notably, Windows supports 'mbcs'
1405 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001406 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001407 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001408
1409 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001410 functions that return filenames (such as os.listdir()) to return Python
1411 string objects pre-encoded using the default file system encoding for
1412 the platform. As this encoding is likely to be different from Python's
1413 default encoding, converting this name to a Unicode object before passing
1414 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001415 would attempt to use its default encoding (generally ASCII) rather than
1416 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001417
Tim Petersa814db52001-05-14 07:05:58 +00001418 In general, this change simply removes surprises when working with
1419 Unicode and the file system, making these operations work as you expect,
1420 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001421 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001422
Tim Peters61dff2b2001-05-08 15:43:37 +00001423- Float (and complex) literals in source code were evaluated to full
1424 precision only when running from a .py file; the same code loaded from a
1425 .pyc (or .pyo) file could suffer numeric differences starting at about the
1426 12th significant decimal digit. For example, on a machine with IEEE-754
1427 floating arithmetic,
1428
1429 x = 9007199254740992.0
1430 print long(x)
1431
1432 printed 9007199254740992 if run directly from .py, but 9007199254740000
1433 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1434 str(float) instead of repr(float) when building code objects. marshal
1435 now uses repr(float) instead, which should reproduce floats to full
1436 machine precision (assuming the platform C float<->string I/O conversion
1437 functions are of good quality).
1438
1439 This may cause floating-point results to change in some cases, and
1440 usually for the better, but may also cause numerically unstable
1441 algorithms to break.
1442
Tim Peters2f228e72001-05-13 00:19:31 +00001443- The implementation of dicts suffers fewer collisions, which has speed
1444 benefits. However, the order in which dict entries appear in dict.keys(),
1445 dict.values() and dict.items() may differ from previous releases for a
1446 given dict. Nothing is defined about this order, so no program should
1447 rely on it. Nevertheless, it's easy to write test cases that rely on the
1448 order by accident, typically because of printing the str() or repr() of a
1449 dict to an "expected results" file. See Lib/test/test_support.py's new
1450 sortdict(dict) function for a simple way to display a dict in sorted
1451 order.
1452
Tim Peters7a3bfc32001-06-12 01:22:22 +00001453- Many other small changes to dicts were made, resulting in faster
1454 operation along the most common code paths.
1455
Guido van Rossum10315822001-05-01 20:54:30 +00001456- Dictionary objects now support the "in" operator: "x in dict" means
1457 the same as dict.has_key(x).
1458
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001459- The update() method of dictionaries now accepts generic mapping
1460 objects. Specifically the argument object must support the .keys()
1461 and __getitem__() methods. This allows you to say, for example,
1462 {}.update(UserDict())
1463
Guido van Rossum10315822001-05-01 20:54:30 +00001464- Iterators were added; this is a generalized way of providing values
1465 to a for loop. See PEP 234. There's a new built-in function iter()
1466 to return an iterator. There's a new protocol to get the next value
1467 from an iterator using the next() method (in Python) or the
1468 tp_iternext slot (in C). There's a new protocol to get iterators
1469 using the __iter__() method (in Python) or the tp_iter slot (in C).
1470 Iterating (i.e. a for loop) over a dictionary generates its keys.
1471 Iterating over a file generates its lines.
1472
Tim Petersf553f892001-05-01 20:45:31 +00001473- The following functions were generalized to work nicely with iterator
1474 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001475 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001476 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1477 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001478 join() method of strings
1479 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001480 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1481 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001482 right-hand side of assignment statements with multiple targets, such as
1483 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001484
Tim Petersd85e1022001-05-11 21:51:48 +00001485- Accessing module attributes is significantly faster (for example,
1486 random.random or os.path or yourPythonModule.yourAttribute).
1487
Tim Peterse63415e2001-05-08 04:38:29 +00001488- Comparing dictionary objects via == and != is faster, and now works even
1489 if the keys and values don't support comparisons other than ==.
1490
Tim Peters95bf9392001-05-10 08:32:44 +00001491- Comparing dictionaries in ways other than == and != is slower: there were
1492 insecurities in the dict comparison implementation that could cause Python
1493 to crash if the element comparison routines for the dict keys and/or
1494 values mutated the dicts. Making the code bulletproof slowed it down.
1495
Tim Peterseb28ef22001-06-02 05:27:19 +00001496- Collisions in dicts are resolved via a new approach, which can help
1497 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001498 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001499 faster now. Thanks to Christian Tismer for pointing out the cause and
1500 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001501
Tim Peters52e155e2001-06-16 05:42:57 +00001502- repr() is much faster for large containers (dict, list, tuple).
1503
1504
Tim Petersa814db52001-05-14 07:05:58 +00001505Library
1506
Fred Drake960fdf92001-07-20 18:38:26 +00001507- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1508 were added to the string module. These a locale-indenpendent
1509 constants, unlike letters, lowercase, and uppercase. These are now
1510 use in appropriate locations in the standard library.
1511
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001512- The flags used in dlopen calls can now be configured using
1513 sys.setdlopenflags and queried using sys.getdlopenflags.
1514
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001515- Fredrik Lundh's xmlrpclib is now a standard library module. This
1516 provides full client-side XML-RPC support. In addition,
1517 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1518 one asyncore-based). Thanks to Eric Raymond for the documentation.
1519
Guido van Rossum643d3912001-07-05 14:46:25 +00001520- The xrange() object is simplified: it no longer supports slicing,
1521 repetition, comparisons, efficient 'in' checking, the tolist()
1522 method, or the start, stop and step attributes. See PEP 260.
1523
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001524- A new function fnmatch.filter to filter lists of file names was added.
1525
Barry Warsawffd674d2001-05-22 16:00:10 +00001526- calendar.py uses month and day names based on the current locale.
1527
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001528- strop is now *really* obsolete (this was announced before with 1.6),
1529 and issues DeprecationWarning when used (except for the four items
1530 that are still imported into string.py).
1531
Tim Petersa814db52001-05-14 07:05:58 +00001532- Cookie.py now sorts key+value pairs by key in output strings.
1533
1534- pprint.isrecursive(object) didn't correctly identify recursive objects.
1535 Now it does.
1536
Tim Peters95b3f782001-05-14 18:39:41 +00001537- pprint functions now much faster for large containers (tuple, list, dict).
1538
Tim Peters7b9542a2001-06-10 23:40:19 +00001539- New 'q' and 'Q' format codes in the struct module, corresponding to C
1540 types "long long" and "unsigned long long" (on Windows, __int64). In
1541 native mode, these can be used only when the platform C compiler supports
1542 these types (when HAVE_LONG_LONG is #define'd by the Python config
1543 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001544 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1545 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001546
Guido van Rossum83213cc2001-06-12 16:48:52 +00001547- The site module installs a new built-in function 'help' that invokes
1548 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1549 it displays a message reminding the user to use 'help()' or
1550 'help(object)'.
1551
Tim Petersa814db52001-05-14 07:05:58 +00001552Tests
1553
1554- New test_mutants.py runs dict comparisons where the key and value
1555 comparison operators mutute the dicts randomly during comparison. This
1556 rapidly causes Python to crash under earlier releases (not for the faint
1557 of heart: it can also cause Win9x to freeze or reboot!).
1558
1559- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001560 pprint.isreadable() return sensible results. Also verifies that simple
1561 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001562
Tim Peters4324aa32001-05-28 22:30:08 +00001563C API
1564
1565- Removed the unused last_is_sticky argument from the internal
1566 _PyTuple_Resize(). If this affects you, you were cheating.
1567
1568
Guido van Rossum55a78992001-07-17 17:22:32 +00001569======================================================================
1570
1571
Guido van Rossumffe13be2001-04-16 18:46:45 +00001572What's New in Python 2.1 (final)?
1573=================================
1574
1575We only changed a few things since the last release candidate, all in
1576Python library code:
1577
1578- A bug in the locale module was fixed that affected locales which
1579 define no grouping for numeric formatting.
1580
1581- A few bugs in the weakref module's implementations of weak
1582 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1583 and the test suite was updated to check for these bugs.
1584
1585- An old bug in the os.path.walk() function (introduced in Python
1586 2.0!) was fixed: a non-existent file would cause an exception
1587 instead of being ignored.
1588
1589- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1590 PyChecker.
1591
1592
Guido van Rossum5b08f132001-04-16 02:05:23 +00001593What's New in Python 2.1c2?
1594===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001595
Guido van Rossum5b08f132001-04-16 02:05:23 +00001596A flurry of small changes, and one showstopper fixed in the nick of
1597time made it necessary to release another release candidate. The list
1598here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001599
Guido van Rossum5b08f132001-04-16 02:05:23 +00001600Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001601
Guido van Rossum5b08f132001-04-16 02:05:23 +00001602- Tim discovered a nasty bug in the dictionary code, caused by
1603 PyDict_Next() calling dict_resize(), and the GC code's use of
1604 PyDict_Next() violating an assumption in dict_items(). This was
1605 fixed with considerable amounts of band-aid, but the net effect is a
1606 saner and more robust implementation.
1607
1608- Made a bunch of symbols static that were accidentally global.
1609
1610Build and Ports
1611
1612- The setup.py script didn't check for a new enough version of zlib
1613 (1.1.3 is needed). Now it does.
1614
1615- Changed "make clean" target to also remove shared libraries.
1616
1617- Added a more general warning about the SGI Irix optimizer to README.
1618
1619Library
1620
1621- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1622 omitted the slash between host and file.html.
1623
1624- The mailbox module's _Mailbox class contained a completely broken
1625 and undocumented seek() method. Ripped it out.
1626
1627- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1628 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1629
1630- Fixed a few last-minute bugs in unittest.
1631
1632Extensions
1633
1634- Reverted the patch to the OpenSSL code in socketmodule.c to support
1635 RAND_status() and the EGD, and the subsequent patch that tried to
1636 fix it for pre-0.9.5 versions; the problem with the patch is that on
1637 some systems it issues a warning whenever socket is imported, and
1638 that's unacceptable.
1639
1640Tests
1641
1642- Fixed the pickle tests to work with "import test.test_pickle".
1643
1644- Tweaked test_locale.py to actually run the test Windows.
1645
1646- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1647 not "wb" (which is not a valid mode at all).
1648
1649- Fix pstats browser crashes. Import readline if it exists to make
1650 the user interface nicer.
1651
1652- Add "import thread" to the top of test modules that import the
1653 threading module (test_asynchat and test_threadedtempfile). This
1654 prevents test failures caused by a broken threading module resulting
1655 from a previously caught failed import.
1656
1657- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1658 needed on some platforms (e.g. Solaris 8) when the tests are run
1659 twice in succession.
1660
1661- Skip rather than fail test_sunaudiodev if no audio device is found.
1662
1663
1664What's New in Python 2.1c1?
1665===========================
1666
1667This list was significantly updated when 2.1c2 was released; the 2.1c1
1668release didn't mention most changes that were actually part of 2.1c1:
1669
1670Legal
1671
1672- Copyright was assigned to the Python Software Foundation (PSF) and a
1673 PSF license (very similar to the CNRI license) was added.
1674
1675- The CNRI copyright notice was updated to include 2001.
1676
1677Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001678
Guido van Rossumc9932722001-04-12 02:31:27 +00001679- After a public outcry, assignment to __debug__ is no longer illegal;
1680 instead, a warning is issued. It will become illegal in 2.2.
1681
Guido van Rossum5b08f132001-04-16 02:05:23 +00001682- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1683 "%#x" now always prepends "0x", even if the value is zero.
1684
1685- Fixed some nits in the bytecode compiler.
1686
1687- Fixed core dumps when calling certain kinds of non-functions.
1688
1689- Fixed various core dumps caused by reference count bugs.
1690
1691Build and Ports
1692
1693- Use INSTALL_SCRIPT to install script files.
1694
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001695- New port: SCO Unixware 7, by Billy G. Allie.
1696
Guido van Rossum5b08f132001-04-16 02:05:23 +00001697- Updated RISCOS port.
1698
1699- Updated BeOS port and notes.
1700
1701- Various other porting problems resolved.
1702
1703Library
1704
1705- The TERMIOS and SOCKET modules are now truly obsolete and
1706 unnecessary. Their symbols are incorporated in the termios and
1707 socket modules.
1708
1709- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1710 better tests for pickling.
1711
1712- threading: make Condition.wait() robust against KeyboardInterrupt.
1713
1714- zipfile: add support to zipfile to support opening an archive
1715 represented by an open file rather than a file name. Fix bug where
1716 the archive was not properly closed. Fixed a bug in this bugfix
1717 where flush() was called for a read-only file.
1718
1719- imputil: added an uninstall() method to the ImportManager.
1720
1721- Canvas: fixed bugs in lower() and tkraise() methods.
1722
1723- SocketServer: API change (added overridable close_request() method)
1724 so that the TCP server can explicitly close the request.
1725
1726- pstats: Eric Raymond added a simple interactive statistics browser,
1727 invoked when the module is run as a script.
1728
1729- locale: fixed a problem in format().
1730
1731- webbrowser: made it work when the BROWSER environment variable has a
1732 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1733 KDE 2. Fixed some other nits.
1734
1735- unittest: changes to allow using a different exception than
1736 AssertionError, and added a few more function aliases. Some other
1737 small changes.
1738
1739- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1740
1741- asynchat: fixed a critical bug in asynchat that slipped through the
1742 2.1b2 release. Fixed another rare bug.
1743
1744- Fix some unqualified except: clauses (always a bad code example).
1745
1746XML
1747
1748- pyexpat: new API get_version_string().
1749
1750- Fixed some minidom bugs.
1751
1752Extensions
1753
1754- Fixed a core dump in _weakref. Removed the weakref.mapping()
1755 function (it adds nothing to the API).
1756
1757- Rationalized the use of header files in the readline module, to make
1758 it compile (albeit with some warnings) with the very recent readline
1759 4.2, without breaking for earlier versions.
1760
1761- Hopefully fixed a buffering problem in linuxaudiodev.
1762
1763- Attempted a fix to make the OpenSSL support in the socket module
1764 work again with pre-0.9.5 versions of OpenSSL.
1765
1766Tests
1767
1768- Added a test case for asynchat and asyncore.
1769
1770- Removed coupling between tests where one test failing could break
1771 another.
1772
1773Tools
1774
1775- Ping added an interactive help browser to pydoc, fixed some nits
1776 in the rest of the pydoc code, and added some features to his
1777 inspect module.
1778
1779- An updated python-mode.el version 4.1 which integrates Ken
1780 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1781 much nicer in XEmacs and Emacs. When stepping through your program
1782 with pdb, in either the shell window or the *Python* window, the
1783 source file and line will be tracked by an arrow. Very cool!
1784
1785- IDLE: syntax warnings in interactive mode are changed into errors.
1786
1787- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001788 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001789
1790- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001791
Barry Warsaw11e89c72001-04-11 20:37:57 +00001792
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001793What's New in Python 2.1 beta 2?
1794================================
1795
Guido van Rossum053ae352001-03-22 14:17:21 +00001796(Unlisted are many fixed bugs, more documentation, etc.)
1797
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001798Core language, builtins, and interpreter
1799
Guido van Rossum053ae352001-03-22 14:17:21 +00001800- The nested scopes work (enabled by "from __future__ import
1801 nested_scopes") is completed; in particular, the future now extends
1802 into code executed through exec, eval() and execfile(), and into the
1803 interactive interpreter.
1804
1805- When calling a base class method (e.g. BaseClass.__init__(self)),
1806 this is now allowed even if self is not strictly spoken a class
1807 instance (e.g. when using metaclasses or the Don Beaudry hook).
1808
1809- Slice objects are now comparable but not hashable; this prevents
1810 dict[:] from being accepted but meaningless.
1811
1812- Complex division is now calculated using less braindead algorithms.
1813 This doesn't change semantics except it's more likely to give useful
1814 results in extreme cases. Complex repr() now uses full precision
1815 like float repr().
1816
1817- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1818
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001819- It is illegal to assign to the name __debug__, which is set when the
1820 interpreter starts. It is effectively a compile-time constant.
1821
1822- A warning will be issued if a global statement for a variable
1823 follows a use or assignment of that variable.
1824
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001825Standard library
1826
Guido van Rossum053ae352001-03-22 14:17:21 +00001827- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1828 inspired by JUnit), is now part of the standard library. You now
1829 have a choice of two testing frameworks: unittest requires you to
1830 write testcases as separate code, doctest gathers them from
1831 docstrings. Both approaches have their advantages and
1832 disadvantages.
1833
1834- A new module Tix was added, which wraps the Tix extension library
1835 for Tk. With that module, it is not necessary to statically link
1836 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1837 require" command. See Demo/tix/.
1838
1839- tzparse.py is now obsolete.
1840
1841- In gzip.py, the seek() and tell() methods are removed -- they were
1842 non-functional anyway, and it's better if callers can test for their
1843 existence with hasattr().
1844
1845Python/C API
1846
1847- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1848 that's already in the dictionary during a PyDict_Next() iteration.
1849 This used to fail occasionally when a dictionary resize operation
1850 could be triggered that would rehash all the keys. All other
1851 modifications to the dictionary are still off-limits during a
1852 PyDict_Next() iteration!
1853
1854- New extended APIs related to passing compiler variables around.
1855
1856- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1857 implement isinstance() and issubclass().
1858
1859- Py_BuildValue() now has a "D" conversion to create a Python complex
1860 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001861
Fred Drake4e262a92001-03-22 18:26:47 +00001862- Extensions types which support weak references must now set the
1863 field allocated for the weak reference machinery to NULL themselves;
1864 this is done to avoid the cost of checking each object for having a
1865 weakly referencable type in PyObject_INIT(), since most types are
1866 not weakly referencable.
1867
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001868- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1869 free variables and cell variables to and from the frame's f_locals.
1870
1871- Variants of several functions defined in pythonrun.h have been added
1872 to support the nested_scopes future statement. The variants all end
1873 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1874 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1875 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001876 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001877
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001878Distutils
1879
1880- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1881 into the release tree.
1882
Tim Peters0e57abf2001-05-02 07:39:38 +00001883- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001884 (an uninstaller, more customization of the installer's display)
1885
1886- from Jack Jansen: added Mac-specific code to generate a dialog for
1887 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001888 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001889 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001890
1891- added 'platforms' and 'keywords' to the set of metadata that can be
1892 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001893
1894- applied patches from Jason Tishler to make the compiler class work with
1895 Cygwin.
1896
1897
Tim Peters2fe289a2001-03-01 22:19:38 +00001898What's New in Python 2.1 beta 1?
1899================================
Tim Petersd66595f2001-02-04 03:09:53 +00001900
1901Core language, builtins, and interpreter
1902
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001903- Following an outcry from the community about the amount of code
1904 broken by the nested scopes feature introduced in 2.1a2, we decided
1905 to make this feature optional, and to wait until Python 2.2 (or at
1906 least 6 months) to make it standard. The option can be enabled on a
1907 per-module basis by adding "from __future__ import nested_scopes" at
1908 the beginning of a module (before any other statements, but after
1909 comments and an optional docstring). See PEP 236 (Back to the
1910 __future__) for a description of the __future__ statement. PEP 227
1911 (Statically Nested Scopes) has been updated to reflect this change,
1912 and to clarify the semantics in a number of endcases.
1913
1914- The nested scopes code, when enabled, has been hardened, and most
1915 bugs and memory leaks in it have been fixed.
1916
1917- Compile-time warnings are now generated for a number of conditions
1918 that will break or change in meaning when nested scopes are enabled:
1919
1920 - Using "from...import *" or "exec" without in-clause in a function
1921 scope that also defines a lambda or nested function with one or
1922 more free (non-local) variables. The presence of the import* or
1923 bare exec makes it impossible for the compiler to determine the
1924 exact set of local variables in the outer scope, which makes it
1925 impossible to determine the bindings for free variables in the
1926 inner scope. To avoid the warning about import *, change it into
1927 an import of explicitly name object, or move the import* statement
1928 to the global scope; to avoid the warning about bare exec, use
1929 exec...in... (a good idea anyway -- there's a possibility that
1930 bare exec will be deprecated in the future).
1931
1932 - Use of a global variable in a nested scope with the same name as a
1933 local variable in a surrounding scope. This will change in
1934 meaning with nested scopes: the name in the inner scope will
1935 reference the variable in the outer scope rather than the global
1936 of the same name. To avoid the warning, either rename the outer
1937 variable, or use a global statement in the inner function.
1938
Neil Schemenauera35c6882001-02-27 04:45:05 +00001939- An optional object allocator has been included. This allocator is
1940 optimized for Python objects and should be faster and use less memory
1941 than the standard system allocator. It is not enabled by default
1942 because of possible thread safety problems. The allocator is only
1943 protected by the Python interpreter lock and it is possible that some
1944 extension modules require a thread safe allocator. The object
1945 allocator can be enabled by providing the "--with-pymalloc" option to
1946 configure.
1947
Tim Petersd66595f2001-02-04 03:09:53 +00001948Standard library
1949
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001950- pyexpat now detects the expat version if expat.h defines it. A
1951 number of additional handlers are provided, which are only available
1952 since expat 1.95. In addition, the methods SetParamEntityParsing and
1953 GetInputContext of Parser objects are available with 1.95.x
1954 only. Parser objects now provide the ordered_attributes and
1955 specified_attributes attributes. A new module expat.model was added,
1956 which offers a number of additional constants if 1.95.x is used.
1957
1958- xml.dom offers the new functions registerDOMImplementation and
1959 getDOMImplementation.
1960
1961- xml.dom.minidom offers a toprettyxml method. A number of DOM
1962 conformance issues have been resolved. In particular, Element now
1963 has an hasAttributes method, and the handling of namespaces was
1964 improved.
1965
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001966- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1967 getting information about live Python code, and pydoc.py, a module
1968 for interactively converting docstrings to HTML or text.
1969 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001970 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001971 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1972 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001973
Tim Peters1eff7962001-03-01 02:31:33 +00001974- New library module difflib.py, primarily packaging the SequenceMatcher
1975 class at the heart of the popular ndiff.py file-comparison tool.
1976
1977- doctest.py (a framework for verifying Python code examples in docstrings)
1978 is now part of the std library.
1979
Tim Petersd66595f2001-02-04 03:09:53 +00001980Windows changes
1981
Guido van Rossume3955a82001-03-02 14:05:59 +00001982- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1983 small GUI that lets you browse the module docstrings using your
1984 default web browser.
1985
Tim Peters1eff7962001-03-01 02:31:33 +00001986- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1987 Platforms) is implemented. See
1988
1989 http://python.sourceforge.net/peps/pep-0235.html
1990
1991 for full details, especially the "Current Lower-Left Semantics" section.
1992 The new Windows import rules are simpler than before:
1993
1994 A. If the PYTHONCASEOK environment variable exists, same as
1995 before: silently accept the first case-insensitive match of any
1996 kind; raise ImportError if none found.
1997
1998 B. Else search sys.path for the first case-sensitive match; raise
1999 ImportError if none found.
2000
2001 The same rules have been implented on other platforms with case-
2002 insensitive but case-preserving filesystems too (including Cygwin, and
2003 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002004
Tim Peters25a9ce32001-02-19 07:06:36 +00002005- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2006 what it's supposed to do (and does do under NT and 2000) via direct
2007 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002008 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002009 all Win9x systems before.
2010
Tim Peters1eff7962001-03-01 02:31:33 +00002011- Build: Subproject _test (effectively) renamed to _testcapi.
2012
Tim Peters2fe289a2001-03-01 22:19:38 +00002013New platforms
2014
2015- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2016 Thanks to Steven Majewski!
2017
2018- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2019 Tishler!
2020
Guido van Rossum9089b272001-03-02 06:49:50 +00002021- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2022 Schwertberger! See RISCOS/README for more information -- it seems
2023 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002024 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002025
Tim Peters25a9ce32001-02-19 07:06:36 +00002026
Tim Petersd7b5e882001-01-25 03:36:26 +00002027What's New in Python 2.1 alpha 2?
2028=================================
Tim Peters40ead762001-01-27 05:35:26 +00002029
Tim Petersd7b5e882001-01-25 03:36:26 +00002030Core language, builtins, and interpreter
2031
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002032- Scopes nest. If a name is used in a function or class, but is not
2033 local, the definition in the nearest enclosing function scope will
2034 be used. One consequence of this change is that lambda statements
2035 could reference variables in the namespaces where the lambda is
2036 defined. In some unusual cases, this change will break code.
2037
2038 In all previous version of Python, names were resolved in exactly
2039 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002040 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002041 function A is defined within a function B, the names bound in B are
2042 not visible in A. The new rules make names bound in B visible in A,
2043 unless A contains a name binding that hides the binding in B.
2044
2045 Section 4.1 of the reference manual describes the new scoping rules
2046 in detail. The test script in Lib/test/test_scope.py demonstrates
2047 some of the effects of the change.
2048
2049 The new rules will cause existing code to break if it defines nested
2050 functions where an outer function has local variables with the same
2051 name as globals or builtins used by the inner function. Example:
2052
2053 def munge(str):
2054 def helper(x):
2055 return str(x)
2056 if type(str) != type(''):
2057 str = helper(str)
2058 return str.strip()
2059
2060 Under the old rules, the name str in helper() is bound to the
2061 builtin function str(). Under the new rules, it will be bound to
2062 the argument named str and an error will occur when helper() is
2063 called.
2064
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002065- The compiler will report a SyntaxError if "from ... import *" occurs
2066 in a function or class scope. The language reference has documented
2067 that this case is illegal, but the compiler never checked for it.
2068 The recent introduction of nested scope makes the meaning of this
2069 form of name binding ambiguous. In a future release, the compiler
2070 may allow this form when there is no possibility of ambiguity.
2071
Tim Peters40ead762001-01-27 05:35:26 +00002072- repr(string) is easier to read, now using hex escapes instead of octal,
2073 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2074
2075 >>> "\texample \r\n" + chr(0) + chr(255)
2076 '\texample \r\n\x00\xff' # in 2.1
2077 '\011example \015\012\000\377' # in 2.0
2078
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002079- Functions are now compared and hashed by identity, not by value, since
2080 the func_code attribute is writable.
2081
Fred Drakefb9d7122001-02-01 20:00:40 +00002082- Weak references (PEP 205) have been added. This involves a few
2083 changes in the core, an extension module (_weakref), and a Python
2084 module (weakref). The weakref module is the public interface. It
2085 includes support for "explicit" weak references, proxy objects, and
2086 mappings with weakly held values.
2087
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002088- A 'continue' statement can now appear in a try block within the body
2089 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002090 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002091
Tim Petersd7b5e882001-01-25 03:36:26 +00002092Standard library
2093
Barry Warsaw30dbd142001-01-31 22:14:01 +00002094- mailbox.py now has a new class, PortableUnixMailbox which is
2095 identical to UnixMailbox but uses a more portable scheme for
2096 determining From_ separators. Also, the constructors for all the
2097 classes in this module have a new optional `factory' argument, which
2098 is a callable used when new message classes must be instantiated by
2099 the next() method.
2100
Tim Petersd7b5e882001-01-25 03:36:26 +00002101- random.py is now self-contained, and offers all the functionality of
2102 the now-deprecated whrandom.py. See the docs for details. random.py
2103 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002104 and restoring the internal state of the generator; and jumpahead(n),
2105 for quickly forcing the internal state to be the same as if n calls to
2106 random() had been made. The latter is particularly useful for multi-
2107 threaded programs, creating one instance of the random.Random() class for
2108 each thread, then using .jumpahead() to force each instance to use a
2109 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002110
Tim Peters0de88fc2001-02-01 04:59:18 +00002111- random.py's seed() function is new. For bit-for-bit compatibility with
2112 prior releases, use the whseed function instead. The new seed function
2113 addresses two problems: (1) The old function couldn't produce more than
2114 about 2**24 distinct internal states; the new one about 2**45 (the best
2115 that can be done in the Wichmann-Hill generator). (2) The old function
2116 sometimes produced identical internal states when passed distinct
2117 integers, and there was no simple way to predict when that would happen;
2118 the new one guarantees to produce distinct internal states for all
2119 arguments in [0, 27814431486576L).
2120
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002121- The socket module now supports raw packets on Linux. The socket
2122 family is AF_PACKET.
2123
Tim Peters9ea17ac2001-02-02 05:57:15 +00002124- test_capi.py is a start at running tests of the Python C API. The tests
2125 are implemented by the new Modules/_testmodule.c.
2126
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002127- A new extension module, _symtable, provides provisional access to the
2128 internal symbol table used by the Python compiler. A higher-level
2129 interface will be added on top of _symtable in a future release.
2130
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002131- Removed the obsolete soundex module.
2132
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002133- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2134 the isSameNode method; NamedNodeMap the get method.
2135
2136- xml.sax.expatreader supports the lexical handler property; it
2137 generates comment, startCDATA, and endCDATA events.
2138
Tim Petersee826f82001-01-31 19:39:44 +00002139Windows changes
2140
2141- Build procedure: the zlib project is built in a different way that
2142 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002143 the zlib binary used. See PCbuild\readme.txt for details. Your old
2144 zlib-related directories can be deleted; you'll need to download fresh
2145 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002146
Tim Peters9ea17ac2001-02-02 05:57:15 +00002147- Build: New subproject _test for the benefit of test_capi.py (see above).
2148
Tim Petersb16c56f2001-02-02 21:24:51 +00002149- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2150 interface to some Python compiler internals).
2151
2152- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002153 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002154
Tim Petersa3a3a032000-11-30 05:22:44 +00002155What's New in Python 2.1 alpha 1?
2156=================================
2157
2158Core language, builtins, and interpreter
2159
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002160- There is a new Unicode companion to the PyObject_Str() API
2161 called PyObject_Unicode(). It behaves in the same way as the
2162 former, but assures that the returned value is an Unicode object
2163 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002164
Guido van Rossumf98eda02001-01-17 15:54:45 +00002165- The comparison operators support "rich comparison overloading" (PEP
2166 207). C extension types can provide a rich comparison function in
2167 the new tp_richcompare slot in the type object. The cmp() function
2168 and the C function PyObject_Compare() first try the new rich
2169 comparison operators before trying the old 3-way comparison. There
2170 is also a new C API PyObject_RichCompare() (which also falls back on
2171 the old 3-way comparison, but does not constrain the outcome of the
2172 rich comparison to a Boolean result).
2173
2174 The rich comparison function takes two objects (at least one of
2175 which is guaranteed to have the type that provided the function) and
2176 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2177 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2178 object, which may be NotImplemented (in which case the tp_compare
2179 slot function is used as a fallback, if defined).
2180
2181 Classes can overload individual comparison operators by defining one
2182 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002183 __ge__. There are no explicit "reflected argument" versions of
2184 these; instead, __lt__ and __gt__ are each other's reflection,
2185 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2186 reflection (similar at the C level). No other implications are
2187 made; in particular, Python does not assume that == is the Boolean
2188 inverse of !=, or that < is the Boolean inverse of >=. This makes
2189 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002190
2191 Classes or types that want to implement (in)equality tests but not
2192 the ordering operators (i.e. unordered types) should implement ==
2193 and !=, and raise an error for the ordering operators.
2194
Guido van Rossuma88479f2001-01-18 14:28:08 +00002195 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002196 Boolean; e.g. a matrix type might want to return a matrix of bits
2197 for A < B, giving elementwise comparisons. Such types should ensure
2198 that any interpretation of their value in a Boolean context raises
2199 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2200 at the C level) to always raise an exception.
2201
Guido van Rossuma88479f2001-01-18 14:28:08 +00002202- Complex numbers use rich comparisons to define == and != but raise
2203 an exception for <, <=, > and >=. Unfortunately, this also means
2204 that cmp() of two complex numbers raises an exception when the two
2205 numbers differ. Since it is not mathematically meaningful to compare
2206 complex numbers except for equality, I hope that this doesn't break
2207 too much code.
2208
Tim Peters3389f192001-02-18 08:48:49 +00002209- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002210 not defined by the language, other than that it's arbitrary but
2211 consistent (see the Reference Manual). An implementation detail changed
2212 in 2.1a1 such that None now compares less than any other object. Code
2213 relying on this new behavior (like code that relied on the previous
2214 behavior) does so at its own risk.
2215
Barry Warsaw573b5412001-01-15 20:43:18 +00002216- Functions and methods now support getting and setting arbitrarily
2217 named attributes (PEP 232). Functions have a new __dict__
2218 (a.k.a. func_dict) which hold the function attributes. Methods get
2219 and set attributes on their underlying im_func. It is a TypeError
2220 to set an attribute on a bound method.
2221
Guido van Rossum051e3352001-01-15 19:11:10 +00002222- The xrange() object implementation has been improved so that
2223 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2224 limitation that in this case len(xrange(sys.maxint)) can't be
2225 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2226 work fine as long as the index i doesn't actually reach 2**31.
2227 (Python uses regular ints for sequence and string indices; fixing
2228 that is much more work.)
2229
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002230- Two changes to from...import:
2231
Guido van Rossumba381232001-02-03 15:06:40 +00002232 1) "from M import X" now works even if (after loading module M)
2233 sys.modules['M'] is not a real module; it's basically a getattr()
2234 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002235
2236 2) "from M import *" now looks for M.__all__ to decide which names to
2237 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2238 filters out names starting with '_' as before. Whether or not
2239 __all__ exists, there's no restriction on the type of M.
2240
Guido van Rossumf61f1662001-01-10 20:13:55 +00002241- File objects have a new method, xreadlines(). This is the fastest
2242 way to iterate over all lines in a file:
2243
2244 for line in file.xreadlines():
2245 ...do something to line...
2246
2247 See the xreadlines module (mentioned below) for how to do this for
2248 other file-like objects.
2249
2250- Even if you don't use file.xreadlines(), you may expect a speedup on
2251 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002252 quite a bit in platform-specific ways: on systems (like Linux) that
2253 support flockfile(), getc_unlocked(), and funlockfile(), those are
2254 used by default. On systems (like Windows) without getc_unlocked(),
2255 a complicated (but still thread-safe) method using fgets() is used by
2256 default.
2257
Tim Petersd52269b2001-01-25 06:23:18 +00002258 You can force use of the fgets() method by #define'ing
2259 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002260 getc_unlocked()).
2261
Tim Petersd52269b2001-01-25 06:23:18 +00002262 You can force fgets() not to be used by #define'ing
2263 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002264 test_bufio.py fails -- and let us know if it does!).
2265
2266- In addition, the fileinput module, while still slower than the other
2267 methods on most platforms, has been sped up too, by using
2268 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002269
2270- Support for run-time warnings has been added, including a new
2271 command line option (-W) to specify the disposition of warnings.
2272 See the description of the warnings module below.
2273
2274- Extensive changes have been made to the coercion code. This mostly
2275 affects extension modules (which can now implement mixed-type
2276 numerical operators without having to use coercion), but
2277 occasionally, in boundary cases the coercion semantics have changed
2278 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002279 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002280 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002281 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002282
Guido van Rossumf98eda02001-01-17 15:54:45 +00002283- In connection with the coercion changes, a new built-in singleton
2284 object, NotImplemented is defined. This can be returned for
2285 operations that wish to indicate they are not implemented for a
2286 particular combination of arguments. From C, this is
2287 Py_NotImplemented.
2288
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002289- The interpreter accepts now bytecode files on the command line even
2290 if they do not have a .pyc or .pyo extension. On Linux, after executing
2291
Martin v. Löwise214baa2001-02-04 22:37:56 +00002292import imp,sys,string
2293magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2294reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2295open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002296
2297 any byte code file can be used as an executable (i.e. as an argument
2298 to execve(2)).
2299
Tim Peters9940b802000-12-01 07:59:35 +00002300- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002301 character. In 1.6 and earlier, they never produced a sign,
2302 and raised an error if the value of the long was too large
2303 to fit in a Python int. In 2.0, they produced a sign if and
2304 only if too large to fit in an int. This was inconsistent
2305 across platforms (because the size of an int varies across
2306 platforms), and inconsistent with hex() and oct(). Example:
2307
2308 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002309 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002310 'ffffffbe' # in 2.0 and before, on 32-bit machines
2311 >>> hex(-0x42L)
2312 '-0x42L' # in all versions of Python
2313
Tim Peters9940b802000-12-01 07:59:35 +00002314 The behavior of %d formats for negative Python longs remains
2315 the same as in 2.0 (although in 1.6 and before, they raised
2316 an error if the long didn't fit in a Python int).
2317
2318 %u formats don't make sense for Python longs, but are allowed
2319 and treated the same as %d in 2.1. In 2.0, a negative long
2320 formatted via %u produced a sign if and only if too large to
2321 fit in an int. In 1.6 and earlier, a negative long formatted
2322 via %u raised an error if it was too big to fit in an int.
2323
Guido van Rossum3661d392000-12-12 22:10:31 +00002324- Dictionary objects have an odd new method, popitem(). This removes
2325 an arbitrary item from the dictionary and returns it (in the form of
2326 a (key, value) pair). This can be useful for algorithms that use a
2327 dictionary as a bag of "to do" items and repeatedly need to pick one
2328 item. Such algorithms normally end up running in quadratic time;
2329 using popitem() they can usually be made to run in linear time.
2330
Tim Peters36cdad12000-12-29 02:06:45 +00002331Standard library
2332
Thomas Woutersfe385252001-01-19 23:16:56 +00002333- In the time module, the time argument to the functions strftime,
2334 localtime, gmtime, asctime and ctime is now optional, defaulting to
2335 the current time (in the local timezone).
2336
Guido van Rossumda91f222001-01-15 16:36:08 +00002337- The ftplib module now defaults to passive mode, which is deemed a
2338 more useful default given that clients are often inside firewalls
2339 these days. Note that this could break if ftplib is used to connect
2340 to a *server* that is inside a firewall, from outside; this is
2341 expected to be a very rare situation. To fix that, you can call
2342 ftp.set_pasv(0).
2343
Martin v. Löwis10a27872001-01-13 09:54:41 +00002344- The module site now treats .pth files not only for path configuration,
2345 but also supports extensions to the initialization code: Lines starting
2346 with import are executed.
2347
Guido van Rossumf61f1662001-01-10 20:13:55 +00002348- There's a new module, warnings, which implements a mechanism for
2349 issuing and filtering warnings. There are some new built-in
2350 exceptions that serve as warning categories, and a new command line
2351 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2352 turns warnings into errors). warnings.warn(message[, category])
2353 issues a warning message; this can also be called from C as
2354 PyErr_Warn(category, message).
2355
2356- A new module xreadlines was added. This exports a single factory
2357 function, xreadlines(). The intention is that this code is the
2358 absolutely fastest way to iterate over all lines in an open
2359 file(-like) object:
2360
2361 import xreadlines
2362 for line in xreadlines.xreadlines(file):
2363 ...do something to line...
2364
2365 This is equivalent to the previous the speed record holder using
2366 file.readlines(sizehint). Note that if file is a real file object
2367 (as opposed to a file-like object), this is equivalent:
2368
2369 for line in file.xreadlines():
2370 ...do something to line...
2371
Tim Peters36cdad12000-12-29 02:06:45 +00002372- The bisect module has new functions bisect_left, insort_left,
2373 bisect_right and insort_right. The old names bisect and insort
2374 are now aliases for bisect_right and insort_right. XXX_right
2375 and XXX_left methods differ in what happens when the new element
2376 compares equal to one or more elements already in the list: the
2377 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002378 right. Code that doesn't care where equal elements end up should
2379 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002380
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002381- The new curses.panel module wraps the panel library that forms part
2382 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2383
Guido van Rossumf61f1662001-01-10 20:13:55 +00002384- The SocketServer module now sets the allow_reuse_address flag by
2385 default in the TCPServer class.
2386
2387- A new function, sys._getframe(), returns the stack frame pointer of
2388 the caller. This is intended only as a building block for
2389 higher-level mechanisms such as string interpolation.
2390
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002391- The pyexpat module supports a number of new handlers, which are
2392 available only in expat 1.2. If invocation of a callback fails, it
2393 will report an additional frame in the traceback. Parser objects
2394 participate now in garbage collection. If expat reports an unknown
2395 encoding, pyexpat will try to use a Python codec; that works only
2396 for single-byte charsets. The parser type objects is exposed as
2397 XMLParserObject.
2398
2399- xml.dom now offers standard definitions for symbolic node type and
2400 exception code constants, and a hierarchy of DOM exceptions. minidom
2401 was adjusted to use them.
2402
2403- The conformance of xml.dom.minidom to the DOM specification was
2404 improved. It detects a number of additional error cases; the
2405 previous/next relationship works even when the tree is modified;
2406 Node supports the normalize() method; NamedNodeMap, DocumentType and
2407 DOMImplementation classes were added; Element supports the
2408 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2409 method.
2410
Guido van Rossumf61f1662001-01-10 20:13:55 +00002411Build issues
2412
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002413- For Unix (and Unix-compatible) builds, configuration and building of
2414 extension modules is now greatly automated. Rather than having to
2415 edit the Modules/Setup file to indicate which modules should be
2416 built and where their include files and libraries are, a
2417 distutils-based setup.py script now takes care of building most
2418 extension modules. All extension modules built this way are built
2419 as shared libraries. Only a few modules that must be linked
2420 statically are still listed in the Setup file; you won't need to
2421 edit their configuration.
2422
2423- Python should now build out of the box on Cygwin. If it doesn't,
2424 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002425
2426- Python now always uses its own (renamed) implementation of getopt()
2427 -- there's too much variation among C library getopt()
2428 implementations.
2429
2430- C++ compilers are better supported; the CXX macro is always set to a
2431 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002432
Tim Petersd92dfe02000-12-12 01:18:41 +00002433Windows changes
2434
2435- select module: By default under Windows, a select() call
2436 can specify no more than 64 sockets. Python now boosts
2437 this Microsoft default to 512. If you need even more than
2438 that, see the MS docs (you'll need to #define FD_SETSIZE
2439 and recompile Python from source).
2440
Guido van Rossumf61f1662001-01-10 20:13:55 +00002441- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2442 subdirectory is no more!
2443
Tim Petersa3a3a032000-11-30 05:22:44 +00002444
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002445What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002446=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002447
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002448Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002449changes are in the file HISTORY. If you are making the jump directly
2450from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2451HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002452
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002453Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2454the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2455http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002456
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002457--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002458
2459======================================================================
2460
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002461What's new in 2.0 (since release candidate 1)?
2462==============================================
2463
2464Standard library
2465
2466- The copy_reg module was modified to clarify its intended use: to
2467 register pickle support for extension types, not for classes.
2468 pickle() will raise a TypeError if it is passed a class.
2469
2470- Fixed a bug in gettext's "normalize and expand" code that prevented
2471 it from finding an existing .mo file.
2472
2473- Restored support for HTTP/0.9 servers in httplib.
2474
Tim Peters989b7b92000-10-16 20:24:53 +00002475- The math module was changed to stop raising OverflowError in case of
2476 underflow, and return 0 instead in underflow cases. Whether Python
2477 used to raise OverflowError in case of underflow was platform-
2478 dependent (it did when the platform math library set errno to ERANGE
2479 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002480
2481- Fixed a bug in StringIO that occurred when the file position was not
2482 at the end of the file and write() was called with enough data to
2483 extend past the end of the file.
2484
2485- Fixed a bug that caused Tkinter error messages to get lost on
2486 Windows. The bug was fixed by replacing direct use of
2487 interp->result with Tcl_GetStringResult(interp).
2488
2489- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2490 redirect response.
2491
2492- Several changes were made to distutils: Some debugging code was
2493 removed from util. Fixed the installer used when an external zip
2494 program (like WinZip) is not found; the source code for this
2495 installer is in Misc/distutils. check_lib() was modified to behave
2496 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2497 test for whether installed modules are on sys.path was changed to
2498 use both normcase() and normpath().
2499
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002500- Several minor bugs were fixed in the xml package (the minidom,
2501 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002502
2503- The regression test driver (regrtest.py) behavior when invoked with
2504 -l changed: It now reports a count of objects that are recognized as
2505 garbage but not freed by the garbage collector.
2506
Tim Peters989b7b92000-10-16 20:24:53 +00002507- The regression test for the math module was changed to test
2508 exceptional behavior when the test is run in verbose mode. Python
2509 cannot yet guarantee consistent exception behavior across platforms,
2510 so the exception part of test_math is run only in verbose mode, and
2511 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002512
2513Internals
2514
2515- PyOS_CheckStack() has been disabled on Win64, where it caused
2516 test_sre to fail.
2517
2518Build issues
2519
2520- Changed compiler flags, so that gcc is always invoked with -Wall and
2521 -Wstrict-prototypes. Users compiling Python with GCC should see
2522 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002523 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002524 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002525
Tim Petersa3a3a032000-11-30 05:22:44 +00002526- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002527
2528Tools and other miscellany
2529
2530- The compiler in Tools/compiler was updated to support the new
2531 language features introduced in 2.0: extended print statement, list
2532 comprehensions, and augmented assignments. The new compiler should
2533 also be backwards compatible with Python 1.5.2; the compiler will
2534 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002535 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002536
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002537What's new in 2.0 release candidate 1 (since beta 2)?
2538=====================================================
2539
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002540What is release candidate 1?
2541
2542We believe that release candidate 1 will fix all known bugs that we
2543intend to fix for the 2.0 final release. This release should be a bit
2544more stable than the previous betas. We would like to see even more
2545widespread testing before the final release, so we are producing this
2546release candidate. The final release will be exactly the same unless
2547any show-stopping (or brown bag) bugs are found by testers of the
2548release candidate.
2549
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002550All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002551to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002552
2553Core language, builtins, and interpreter
2554
2555- A bug that caused crashes when __coerce__ was used with augmented
2556 assignment, e.g. +=, was fixed.
2557
2558- Raise ZeroDivisionError when raising zero to a negative number,
2559 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2560 power operator and the result of math.pow(0.0, -2.0) will vary by
2561 platform. On Linux, it raises a ValueError.
2562
2563- A bug in Unicode string interpolation was fixed that occasionally
2564 caused errors with formats including "%%". For example, the
2565 following expression "%% %s" % u"abc" no longer raises a TypeError.
2566
2567- Compilation of deeply nested expressions raises MemoryError instead
2568 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2569
2570- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2571 rendering them useless. They are now written in binary mode again.
2572
2573Standard library
2574
2575- Keyword arguments are now accepted for most pattern and match object
2576 methods in SRE, the standard regular expression engine.
2577
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002578- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002579 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002580
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002581- Several bugs in the Unicode handling and error handling in _tkinter
2582 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002583
2584- Fix memory management errors in Merge() and Tkapp_Call() routines.
2585
2586- Several changes were made to cStringIO to make it compatible with
2587 the file-like object interface and with StringIO. If operations are
2588 performed on a closed object, an exception is raised. The truncate
2589 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002590 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002591
2592- There were many changes made to the linuxaudiodev module and its
2593 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002594 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002595
2596 Note that this module is named poorly, because it should work
2597 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002598 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002599
2600 The module now raises exceptions when errors occur instead of
2601 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2602 audio) and defines a getptr() method that calls the
2603 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2604
2605- The library_version attribute, introduced in an earlier beta, was
2606 removed because it can not be supported with early versions of the C
2607 readline library, which provides no way to determine the version at
2608 compile-time.
2609
2610- The binascii module is now enabled on Win64.
2611
Tim Peters46446d62000-10-09 21:19:31 +00002612- tokenize.py no longer suffers "recursion depth" errors when parsing
2613 programs with very long string literals.
2614
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002615Internals
2616
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002617- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002618 which is called when the interpreter starts up to determine where
2619 the standard library is installed. These vulnerabilities affect all
2620 previous versions of Python and can be exploited by setting very
2621 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2622 setuid Python script, although use of the wrapper in
2623 Misc/setuid-prog.c will eliminate the vulnerability.
2624
2625- Fixed garbage collection bugs in instance creation that were
2626 triggered when errors occurred during initialization. The solution,
2627 applied in cPickle and in PyInstance_New(), is to call
2628 PyObject_GC_Init() after the initialization of the object's
2629 container attributes is complete.
2630
2631- pyexpat adds definitions of PyModule_AddStringConstant and
2632 PyModule_AddObject if the Python version is less than 2.0, which
2633 provides compatibility with PyXML on Python 1.5.2.
2634
2635- If the platform has a bogus definition for LONG_BIT (the number of
2636 bits in a long), an error will be reported at compile time.
2637
2638- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2639 collection crashes and possibly other, unreported crashes.
2640
2641- Fixed a memory leak in _PyUnicode_Fini().
2642
2643Build issues
2644
2645- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002646 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002647 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002648
2649- The mmap.PAGESIZE constant is now initialized using sysconf when
2650 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2651
2652- The md5 file should now compile on all platforms.
2653
2654- The select module now compiles on platforms that do not define
2655 POLLRDNORM and related constants.
2656
2657- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002658 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002659
Jeremy Hylton10921202000-10-09 18:34:12 +00002660- BeOS: A number of changes were made to the build and installation
2661 process. ar-fake now operates on a directory of object files.
2662 dl_export.h is gone, and its macros now appear on the mwcc command
2663 line during build on PPC BeOS.
2664
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002665- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002666 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002667
2668- Cygwin: Support for shared libraries, Tkinter, and sockets.
2669
2670- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2671
2672Tools and other miscellany
2673
2674- Removed debugging prints from main used with freeze.
2675
Tim Peters46446d62000-10-09 21:19:31 +00002676- IDLE auto-indent no longer crashes when it encounters Unicode
2677 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002678
2679What's new in 2.0 beta 2 (since beta 1)?
2680========================================
2681
2682Core language, builtins, and interpreter
2683
Tim Peters482c0212000-09-26 06:33:09 +00002684- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002685 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002686
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002687- Add -h and -V command line options to print the usage message and
2688 Python version number and exit immediately.
2689
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002690- eval() and exec accept Unicode objects as code parameters.
2691
2692- getattr() and setattr() now also accept Unicode objects for the
2693 attribute name, which are converted to strings using the default
2694 encoding before lookup.
2695
2696- Multiplication on string and Unicode now does proper bounds
2697 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2698 string is too long."
2699
2700- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002701 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002702
Jeremy Hylton1b618592000-09-26 05:32:36 +00002703
2704Standard library and extensions
2705
Guido van Rossum5b08f132001-04-16 02:05:23 +00002706- socket module: the OpenSSL code now adds support for RAND_status()
2707 and EGD (Entropy Gathering Device).
2708
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002709- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002710 argument checking; it still takes no arguments.
2711
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002712- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002713
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002714- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002715
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002716- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002717
2718- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002719 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002720
2721- copy: Copy Unicode objects atomically.
2722
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002723- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002724
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002725- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002726
Fred Drake67233bc2000-09-26 16:40:27 +00002727- dbm: Add get() and setdefault() methods to dbm object. Add constant
2728 `library' to module that names the library used. Added doc strings
2729 and method names to error messages. Uses configure to determine
2730 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2731 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002732
2733- distutils: Update to version 0.9.3.
2734
2735- dl: Add several dl.RTLD_ constants.
2736
2737- fpectl: Now supported on FreeBSD.
2738
2739- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2740 found by the collector will be saved in gc.garbage. This is useful
2741 for debugging a program that creates reference cycles.
2742
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002743- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002744 of HTTP class. Do not close socket on zero-length response. Do not
2745 crash when server sends invalid content-length header.
2746
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002747- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002748
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002749- marshal: When reading a short, sign-extend on platforms where shorts
2750 are bigger than 16 bits. When reading a long, repair the unportable
2751 sign extension that was being done for 64-bit machines. (It assumed
2752 that signed right shift sign-extends.)
2753
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002754- operator: Add contains(), invert(), __invert__() as aliases for
2755 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002756
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002757- os: Add support for popen2() and popen3() on all platforms where
2758 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002759
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002760- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002761 clicking on a file in Explorer (or passing the file name to the
2762 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002763
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002764- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002765 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002766
2767- pickle: Now raises ValueError when an invalid pickle that contains
2768 a non-string repr where a string repr was expected. This behavior
2769 matches cPickle.
2770
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002771- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002772
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002773- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002774
2775- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002776 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002777 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778
2779- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002780 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002781
2782- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002783 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002784 few cycles during startup since the first call to
2785 setdefaultencoding() will initialize the codec registry and the
2786 encodings package.
2787
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002788- socket: Support for size hint in readlines() method of object returned
2789 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002790
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002791- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002792 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793 is followed by whitespace.
2794
Tim Petersa3a3a032000-11-30 05:22:44 +00002795- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002796
2797- struct: Check ranges for bytes and shorts.
2798
2799- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002800 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002801
2802- Tkinter: Image objects are now guaranteed to have unique ids. Set
2803 event.delta to zero if Tk version doesn't support mousewheel.
2804 Removed some debugging prints.
2805
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002806- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002807
Fred Drake67233bc2000-09-26 16:40:27 +00002808- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002809 which works around a bug in Norton AntiVirus 2000 that leads directly
2810 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002811
2812- xml: New version detection code allows PyXML to override standard
2813 XML package if PyXML version is greater than 0.6.1.
2814
Fred Drake64bb3802000-09-26 16:21:35 +00002815- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2816 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2817 tree only for nodes which are sufficiently interesting to a specific
2818 application. Does not provide the HTML-specific extensions. Still
2819 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002820
Fred Drake64bb3802000-09-26 16:21:35 +00002821- xml.sax: SAX 2 support for Python, including all the handler
2822 interfaces needed to process XML 1.0 compliant XML. Some
2823 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002824
Fred Drake64bb3802000-09-26 16:21:35 +00002825- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2826 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002827
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002828
Jeremy Hylton1b618592000-09-26 05:32:36 +00002829C API
2830
2831- Add three new convenience functions for module initialization --
2832 PyModule_AddObject(), PyModule_AddIntConstant(), and
2833 PyModule_AddStringConstant().
2834
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002835- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002836 removed and add #error to Python.h if NULL isn't defined after
2837 #include of stdio.h.
2838
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002839- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002840 backwards compatibility (at the source level) with old extensions.
2841
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002842- A wrapper API was added for signal() and sigaction(). Instead of
2843 either function, always use PyOS_getsig() to get a signal handler
2844 and PyOS_setsig() to set one. A new convenience typedef
2845 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002846
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002847- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002848 internal data buffer and size of a string object -- or the default
2849 encoded version of a Unicode object.
2850
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002851- PyString_Size() and PyString_AsString() accept Unicode objects.
2852
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002853- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002854 exists). INT_MAX and LONG_MAX will always be defined, even if
2855 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002856
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002857- PyFloat_FromString takes a second argument, pend, that was
2858 effectively useless. It is now officially useless but preserved for
2859 backwards compatibility. If the pend argument is not NULL, *pend is
2860 set to NULL.
2861
2862- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2863 for the attribute name. See note on getattr() above.
2864
2865- A few bug fixes to argument processing for Unicode.
2866 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2867 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2868 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002869 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002870
2871- Py_BuildValue accepts B format (for bgen-generated code).
2872
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002873
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874Internals
2875
2876- On Unix, fix code for finding Python installation directory so that
2877 it works when argv[0] is a relative path.
2878
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002879- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002880 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002881 rather than by generating a copy of the object.
2882
Tim Peters482c0212000-09-26 06:33:09 +00002883- Several of the internal Unicode tables are much smaller now, and
2884 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002885
Jeremy Hylton97693b02000-09-26 17:42:51 +00002886- In the garbage collector: Fixed bug in collection of tuples. Fixed
2887 bug that caused some instances to be removed from the container set
2888 while they were still live. Fixed parsing in gc.set_debug() for
2889 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002890
2891- Fixed refcount problem in instance deallocation that only occurred
2892 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2893
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002894- On Windows, getpythonregpath is now protected against null data in
2895 registry key.
2896
2897- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002898 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002899
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002900
Jeremy Hylton1b618592000-09-26 05:32:36 +00002901Build and platform-specific issues
2902
2903- Better support of GNU Pth via --with-pth configure option.
2904
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002905- Python/C API now properly exposed to dynamically-loaded extension
2906 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002907
2908- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2909 Don't define MS_SYNC to be zero when it is undefined. Added missing
2910 prototypes in posixmodule.c.
2911
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002912- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002913 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002914
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002915- Fix largefile support on older NetBSD systems and OpenBSD by adding
2916 define for TELL64.
2917
2918
2919Tools and other miscellany
2920
2921- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2922
2923- freeze: The modulefinder now works with 2.0 opcodes.
2924
Tim Petersa3a3a032000-11-30 05:22:44 +00002925- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002926 Move hackery of sys.argv until after the Tk instance has been
2927 created, which allows the application-specific Tkinter
2928 initialization to be executed if present; also pass an explicit
2929 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002930
Jeremy Hylton1b618592000-09-26 05:32:36 +00002931
2932What's new in 2.0 beta 1?
2933=========================
2934
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002935Source Incompatibilities
2936------------------------
2937
2938None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2939such as single-argument append(), connect() and bind(), and changes to
2940str(long) and repr(float).
2941
2942
2943Binary Incompatibilities
2944------------------------
2945
2946- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2947with Python 2.0; these extensions will have to be rebuilt for Python
29482.0.
2949
2950- On Windows, attempting to import a third party extension built for
2951Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2952can do about this. Check your PYTHONPATH environment variable!
2953
2954- Python bytecode files (*.pyc and *.pyo) are not compatible between
2955releases.
2956
2957
2958Overview of Changes Since 1.6
2959-----------------------------
2960
2961There are many new modules (including brand new XML support through
2962the xml package, and i18n support through the gettext module); a list
2963of all new modules is included below. Lots of bugs have been fixed.
2964
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002965The process for making major new changes to the language has changed
2966since Python 1.6. Enhancements must now be documented by a Python
2967Enhancement Proposal (PEP) before they can be accepted.
2968
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002969There are several important syntax enhancements, described in more
2970detail below:
2971
2972 - Augmented assignment, e.g. x += 1
2973
2974 - List comprehensions, e.g. [x**2 for x in range(10)]
2975
2976 - Extended import statement, e.g. import Module as Name
2977
2978 - Extended print statement, e.g. print >> file, "Hello"
2979
2980Other important changes:
2981
2982 - Optional collection of cyclical garbage
2983
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002984Python Enhancement Proposal (PEP)
2985---------------------------------
2986
2987PEP stands for Python Enhancement Proposal. A PEP is a design
2988document providing information to the Python community, or describing
2989a new feature for Python. The PEP should provide a concise technical
2990specification of the feature and a rationale for the feature.
2991
2992We intend PEPs to be the primary mechanisms for proposing new
2993features, for collecting community input on an issue, and for
2994documenting the design decisions that have gone into Python. The PEP
2995author is responsible for building consensus within the community and
2996documenting dissenting opinions.
2997
2998The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002999
3000Augmented Assignment
3001--------------------
3002
3003This must have been the most-requested feature of the past years!
3004Eleven new assignment operators were added:
3005
Guido van Rossume905e952000-09-05 12:42:46 +00003006 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003007
3008For example,
3009
3010 A += B
3011
3012is similar to
3013
3014 A = A + B
3015
3016except that A is evaluated only once (relevant when A is something
3017like dict[index].attr).
3018
3019However, if A is a mutable object, A may be modified in place. Thus,
3020if A is a number or a string, A += B has the same effect as A = A+B
3021(except A is only evaluated once); but if a is a list, A += B has the
3022same effect as A.extend(B)!
3023
3024Classes and built-in object types can override the new operators in
3025order to implement the in-place behavior; the not-in-place behavior is
3026used automatically as a fallback when an object doesn't implement the
3027in-place behavior. For classes, the method name is derived from the
3028method name for the corresponding not-in-place operator by inserting
3029an 'i' in front of the name, e.g. __iadd__ implements in-place
3030__add__.
3031
3032Augmented assignment was implemented by Thomas Wouters.
3033
3034
3035List Comprehensions
3036-------------------
3037
3038This is a flexible new notation for lists whose elements are computed
3039from another list (or lists). The simplest form is:
3040
3041 [<expression> for <variable> in <sequence>]
3042
Guido van Rossum56db0952000-09-06 23:34:25 +00003043For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003044This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003045
3046You can also add a condition:
3047
3048 [<expression> for <variable> in <sequence> if <condition>]
3049
3050For example, [w for w in words if w == w.lower()] would yield the list
3051of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003052than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003053
3054You can also have nested for loops and more than one 'if' clause. For
3055example, here's a function that flattens a sequence of sequences::
3056
3057 def flatten(seq):
3058 return [x for subseq in seq for x in subseq]
3059
3060 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3061
3062This prints
3063
3064 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3065
3066List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003067Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003068
3069
3070Extended Import Statement
3071-------------------------
3072
3073Many people have asked for a way to import a module under a different
3074name. This can be accomplished like this:
3075
3076 import foo
3077 bar = foo
3078 del foo
3079
3080but this common idiom gets old quickly. A simple extension of the
3081import statement now allows this to be written as follows:
3082
3083 import foo as bar
3084
3085There's also a variant for 'from ... import':
3086
3087 from foo import bar as spam
3088
3089This also works with packages; e.g. you can write this:
3090
3091 import test.regrtest as regrtest
3092
3093Note that 'as' is not a new keyword -- it is recognized only in this
3094context (this is only possible because the syntax for the import
3095statement doesn't involve expressions).
3096
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003097Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003098
3099
3100Extended Print Statement
3101------------------------
3102
3103Easily the most controversial new feature, this extension to the print
3104statement adds an option to make the output go to a different file
3105than the default sys.stdout.
3106
3107For example, to write an error message to sys.stderr, you can now
3108write:
3109
3110 print >> sys.stderr, "Error: bad dog!"
3111
3112As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003113evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003114
3115 print >> None, "Hello world"
3116
3117is equivalent to
3118
3119 print "Hello world"
3120
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003121Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003122
3123
3124Optional Collection of Cyclical Garbage
3125---------------------------------------
3126
3127Python is now equipped with a garbage collector that can hunt down
3128cyclical references between Python objects. It's no replacement for
3129reference counting; in fact, it depends on the reference counts being
3130correct, and decides that a set of objects belong to a cycle if all
3131their reference counts can be accounted for from their references to
3132each other. This devious scheme was first proposed by Eric Tiedemann,
3133and brought to implementation by Neil Schemenauer.
3134
3135There's a module "gc" that lets you control some parameters of the
3136garbage collection. There's also an option to the configure script
3137that lets you enable or disable the garbage collection. In 2.0b1,
3138it's on by default, so that we (hopefully) can collect decent user
3139experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003140performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003141off by default in the final 2.0 release.
3142
3143
3144Smaller Changes
3145---------------
3146
3147A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3148map(None, seq1, seq2, ...) when the sequences have the same length;
3149i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3150the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003151zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003152
3153sys.version_info is a tuple (major, minor, micro, level, serial).
3154
3155Dictionaries have an odd new method, setdefault(key, default).
3156dict.setdefault(key, default) returns dict[key] if it exists; if not,
3157it sets dict[key] to default and returns that value. Thus:
3158
3159 dict.setdefault(key, []).append(item)
3160
3161does the same work as this common idiom:
3162
3163 if not dict.has_key(key):
3164 dict[key] = []
3165 dict[key].append(item)
3166
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003167There are two new variants of SyntaxError that are raised for
3168indentation-related errors: IndentationError and TabError.
3169
3170Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3171escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003172
3173The limits on the size of expressions and file in Python source code
3174have been raised from 2**16 to 2**32. Previous versions of Python
3175were limited because the maximum argument size the Python VM accepted
3176was 2**16. This limited the size of object constructor expressions,
3177e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3178limit was raised thanks to a patch by Charles Waldman that effectively
3179fixes the problem. It is now much more likely that you will be
3180limited by available memory than by an arbitrary limit in Python.
3181
3182The interpreter's maximum recursion depth can be modified by Python
3183programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3184limit is the maximum number of recursive calls that can be made by
3185Python code. The limit exists to prevent infinite recursion from
3186overflowing the C stack and causing a core dump. The default value is
31871000. The maximum safe value for a particular platform can be found
3188by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003189
3190New Modules and Packages
3191------------------------
3192
3193atexit - for registering functions to be called when Python exits.
3194
3195imputil - Greg Stein's alternative API for writing custom import
3196hooks.
3197
3198pyexpat - an interface to the Expat XML parser, contributed by Paul
3199Prescod.
3200
3201xml - a new package with XML support code organized (so far) in three
3202subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3203would fill a volume. There's a special feature whereby a
3204user-installed package named _xmlplus overrides the standard
3205xmlpackage; this is intended to give the XML SIG a hook to distribute
3206backwards-compatible updates to the standard xml package.
3207
3208webbrowser - a platform-independent API to launch a web browser.
3209
3210
Guido van Rossume905e952000-09-05 12:42:46 +00003211Changed Modules
3212---------------
3213
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003214array -- new methods for array objects: count, extend, index, pop, and
3215remove
3216
3217binascii -- new functions b2a_hex and a2b_hex that convert between
3218binary data and its hex representation
3219
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003220calendar -- Many new functions that support features including control
3221over which day of the week is the first day, returning strings instead
3222of printing them. Also new symbolic constants for days of week,
3223e.g. MONDAY, ..., SUNDAY.
3224
3225cgi -- FieldStorage objects have a getvalue method that works like a
3226dictionary's get method and returns the value attribute of the object.
3227
3228ConfigParser -- The parser object has new methods has_option,
3229remove_section, remove_option, set, and write. They allow the module
3230to be used for writing config files as well as reading them.
3231
3232ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003233optionally support the RFC 959 REST command.
3234
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003235gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003236
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003237httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3238the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003239
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003240locale -- implement getdefaultlocale for Win32 and Macintosh
3241
3242marshal -- no longer dumps core when marshaling deeply nested or
3243recursive data structures
3244
3245os -- new functions isatty, seteuid, setegid, setreuid, setregid
3246
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003247os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3248support under Unix.
3249
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003250os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003251
3252os.path -- fix semantics of os.path.commonprefix
3253
3254smtplib -- support for sending very long messages
3255
3256socket -- new function getfqdn()
3257
3258readline -- new functions to read, write and truncate history files.
3259The readline section of the library reference manual contains an
3260example.
3261
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003262select -- add interface to poll system call
3263
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003264shutil -- new copyfileobj function
3265
3266SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3267HTTP server.
3268
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003269Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003270
3271urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003272e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003273
3274whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003275
3276
3277Obsolete Modules
3278----------------
3279
3280None. However note that 1.6 made a whole slew of modules obsolete:
3281stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3282poly, zmod, strop, util, whatsound.
3283
3284
3285Changed, New, Obsolete Tools
3286----------------------------
3287
Tim Peters8b092332000-09-05 20:15:25 +00003288None.
Guido van Rossume905e952000-09-05 12:42:46 +00003289
3290
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003291C-level Changes
3292---------------
3293
3294Several cleanup jobs were carried out throughout the source code.
3295
3296All C code was converted to ANSI C; we got rid of all uses of the
3297Py_PROTO() macro, which makes the header files a lot more readable.
3298
3299Most of the portability hacks were moved to a new header file,
3300pyport.h; several other new header files were added and some old
3301header files were removed, in an attempt to create a more rational set
3302of header files. (Few of these ever need to be included explicitly;
3303they are all included by Python.h.)
3304
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003305Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003306and Win64, especially for the new Intel Itanium processor. Mick also
3307added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003308
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003309The C APIs to return an object's size have been update to consistently
3310use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3311previous versions, the abstract interfaces used PyXXX_Length and the
3312concrete interfaces used PyXXX_Size. The old names,
3313e.g. PyObject_Length, are still available for backwards compatibility
3314at the API level, but are deprecated.
3315
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003316The PyOS_CheckStack function has been implemented on Windows by
3317Fredrik Lundh. It prevents Python from failing with a stack overflow
3318on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003319
3320The GC changes resulted in creation of two new slots on object,
3321tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003322the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003323
3324The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003325C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003326
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003327PyErr_Format has been updated to automatically calculate the size of
3328the buffer needed to hold the formatted result string. This change
3329prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003330
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003331New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003332
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003333PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3334that are the same as their non-Ex counterparts except they take an
3335extra flag argument that tells them to close the file when done.
3336
3337XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003338
Tim Peters8b092332000-09-05 20:15:25 +00003339
3340Windows Changes
3341---------------
3342
3343New popen2/popen3/peopen4 in os module (see Changed Modules above).
3344
3345os.popen is much more usable on Windows 95 and 98. See Microsoft
3346Knowledge Base article Q150956. The Win9x workaround described there
3347is implemented by the new w9xpopen.exe helper in the root of your
3348Python installation. Note that Python uses this internally; it is not
3349a standalone program.
3350
3351Administrator privileges are no longer required to install Python
3352on Windows NT or Windows 2000. If you have administrator privileges,
3353Python's registry info will be written under HKEY_LOCAL_MACHINE.
3354Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003355under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003356uses of Python, but will prevent some advanced uses from working
3357(for example, running a Python script as an NT service, or possibly
3358from CGI).
3359
3360[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3361installer; instead, it installs the needed Tcl/Tk files directly in the
3362Python directory. If you already have a Tcl/Tk installation, this
3363wastes some disk space (about 4 Megs) but avoids problems with
3364conflicting Tcl/Tk installations, and makes it much easier for Python
3365to ensure that Tcl/Tk can find all its files.
3366
3367[This was new in 1.6] The Windows installer now installs by default in
3368\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3369
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003370
3371Updates to the changes between 1.5.2 and 1.6
3372--------------------------------------------
3373
3374The 1.6 NEWS file can't be changed after the release is done, so here
3375is some late-breaking news:
3376
3377New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3378and changes to getlocale() and setlocale().
3379
3380The new module is now enabled per default.
3381
3382It is not true that the encodings codecs cannot be used for normal
3383strings: the string.encode() (which is also present on 8-bit strings
3384!) allows using them for 8-bit strings too, e.g. to convert files from
3385cp1252 (Windows) to latin-1 or vice-versa.
3386
3387Japanese codecs are available from Tamito KAJIYAMA:
3388http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3389
3390
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003391======================================================================