blob: c63db58bddbc355f1b86af15af7523a12d073541 [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
Neil Schemenauer89e3ee02002-04-26 01:58:53 +00009- The assert statement no longer tests __debug__ at runtime. This means
10 that assert statements cannot be disabled by assigning a false value
11 to __debug__.
12
Walter Dörwald068325e2002-04-15 13:36:47 +000013- A method zfill() was added to str and unicode, that fills a numeric
14 string to the left with zeros. For example,
15 "+123".zfill(6) -> "+00123".
16
Guido van Rossum862fe3c2002-04-15 12:36:47 +000017- Complex numbers supported divmod() and the // and % operators, but
18 these make no sense. Since this was documented, they're being
19 deprecated now.
20
Guido van Rossum49042042002-04-13 00:59:05 +000021- String methods lstrip(), rstrip() and strip() now take an optional
22 argument that specifies the characters to strip. For example,
23 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
24
Guido van Rossumc69343b2002-04-12 19:22:48 +000025- Added a new dict method pop(key). This removes and returns the
26 value corresponding to key. [SF patch #539949]
27
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000028- Changed new-style class instantiation so that when C's __new__
29 method returns something that's not a C instance, its __init__ is
30 not called. [SF bug #537450]
31
Guido van Rossum181e41a2002-04-06 00:23:25 +000032- Fixed super() to work correctly with class methods. [SF bug #535444]
33
Guido van Rossum47834462002-04-04 15:21:33 +000034- A new built-in type, bool, has been added, as well as built-in
35 names for its two values, True and False. Comparisons and sundry
36 other operations that return a truth value have been changed to
37 return a bool instead. Read PEP 285 for an explanantion of why this
38 is backward compatible.
39
Guido van Rossum95b62a62002-03-29 01:07:24 +000040- Fixed two bugs reported as SF #535905: under certain conditions,
41 deallocating a deeply nested structure could cause a segfault in the
42 garbage collector, due to interaction with the "trashcan" code;
43 access to the current frame during destruction of a local variable
44 could access a pointer to freed memory.
45
Neil Schemenauer9d50d132002-03-22 17:06:59 +000046- The optional object allocator has been enabled by default.
47
Guido van Rossum8c842552002-03-14 23:05:54 +000048- If you try to pickle an instance of a class that has __slots__ but
49 doesn't define or override __getstate__, a TypeError is now raised.
50 This is done by adding a bozo __getstate__ to the class that always
51 raises TypeError. (Before, this would appear to be pickled, but the
52 state of the slots would be lost.)
53
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000054- PyErr_Display will provide file and line information for all exceptions
55 that have an attribute print_file_and_line, not just SyntaxErrors.
56
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000057- The UTF-8 codec will now encode and decode Unicode surrogates
58 correctly and without raising exceptions for unpaired ones.
59
Neal Norwitz649b7592002-01-01 19:07:13 +000060- file.xreadlines() now raises a ValueError if the file is closed:
61 Previously, an xreadlines object was returned which would raise
62 a ValueError when the xreadlines.next() method was called.
63
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000064- posix.killpg has been added where available.
65
Neal Norwitz0c766a02002-03-27 13:03:09 +000066- sys.exit() inadvertantly allowed more than one argument.
67 An exception will now be raised if more than one argument is used.
68
Tim Petersaf8446f2001-12-21 21:36:50 +000069Extension modules
70
Anthony Baxter83888952002-04-23 02:11:05 +000071- The bsddb.*open functions can now take 'None' as a filename.
72 This will create a temporary in-memory bsddb that won't be
73 written to disk.
74
Martin v. Löwis06a83e92002-04-14 10:19:44 +000075- posix.mknod was added.
76
Martin v. Löwis2e64c342002-03-27 18:49:02 +000077- The locale module now exposes the C library's gettext interface.
78
Tim Petersfbf74f22002-03-14 19:06:01 +000079- A security hole ("double free") was found in zlib-1.1.3, a popular
80 third party compression library used by some Python modules. The
81 hole was quickly plugged in zlib-1.1.4, and the Windows build of
82 Python now ships with zlib-1.1.4.
83
Martin v. Löwis688357e2002-04-08 21:28:20 +000084- pwd, grp, and resource return enhanced tuples now, with symbolic
85 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000086
Martin v. Löwis99866332002-03-01 10:27:01 +000087- array.array is now a type object. A new format character
88 'u' indicates Py_UNICODE arrays. For those, .tounicode and
89 .fromunicode methods are available. Arrays now support __iadd__
90 and __imul__.
91
Neal Norwitze790eae2002-01-01 21:14:12 +000092- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000093 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
94 is called.
95
Tim Petersaf8446f2001-12-21 21:36:50 +000096Library
97
Guido van Rossum256705b2002-04-23 13:29:43 +000098- New Text.dump() method in Tkinter module.
99
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000100- New distutils commands for building packagers were added to
101 support pkgtool on Solaris and swinstall on HP-UX.
102
103- distutils now has a new abstract binary packager base class
104 command/bdist_packager, which simplifies writing packagers.
105 This will hopefully provide the missing bits to encourage
106 people to submit more packagers, e.g. for Debian, FreeBSD
107 and other systems.
108
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000109- The UTF-16, -LE and -BE now raise a NotImplementedError
110 for all calls to .readline(). Previously, they used to just
111 produce garbage or fail with an encoding error -- UTF-16 is
112 a 2-byte encoding and the C lib's line reading APIs don't
113 work well with these.
114
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000115- compileall now supports quiet operation.
116
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000117- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
118 connections.
119
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000120- socket module: the SSL support was broken out of the main
121 _socket module C helper and placed into a new _ssl helper
122 which now gets imported by socket.py if available and working.
123
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000124- encodings package: added aliases for all supported IANA character
125 sets
126
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000127- ftplib: to safeguard the user's privacy, anonymous login will use
128 "anonymous@" as default password, rather than the real user and host
129 name.
130
Fred Drake36736122002-01-10 13:50:31 +0000131- webbrowser: tightened up the command passed to os.system() so that
132 arbitrary shell code can't be executed because a bogus URL was
133 passed in.
134
Tim Peters11bd9942002-02-01 00:52:29 +0000135- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000136 gettext.find an optional all argument. Translations will now fallback
137 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000138
Martin v. Löwis9668b932002-01-12 11:27:42 +0000139- distutils bdist commands now offer a --skip-build option.
140
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000141- warnings.warn now accepts a Warning instance as first argument.
142
Fred Drakefed7e852002-04-04 19:36:15 +0000143- The xml.sax.expatreader.ExpatParser class will no longer create
144 circular references by using itself as the locator that gets passed
145 to the content handler implementation. [SF bug #535474]
146
Tim Petersaf8446f2001-12-21 21:36:50 +0000147Tools/Demos
148
Marc-André Lemburg46260092002-04-04 16:17:11 +0000149- freeze.py now produces binaries which can import shared modules,
150 unlike before when this failed due to missing symbol exports in
151 the generated binary.
152
Tim Petersaf8446f2001-12-21 21:36:50 +0000153Build
154
Tim Peters639295f2002-04-21 07:30:30 +0000155- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
156 say how or when to configure it, or how to turn it off.
157
Martin v. Löwis1142de32002-03-29 16:28:31 +0000158- On Unix, a shared libpython2.3.so can be created with --enable-shared.
159
Tim Peters8deda702002-03-30 10:06:07 +0000160- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
161 preprocessor symbols were eliminated. The internal decisions they
162 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000163
Tim Petersaf8446f2001-12-21 21:36:50 +0000164C API
165
Guido van Rossum517c7d42002-04-26 02:49:14 +0000166- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
167 coercion if both arguments have the same type but this type has the
168 CHECKTYPES flag set. This is to better support proxies.
169
Neil Schemenauer9344b142002-04-12 23:00:08 +0000170- The type of tp_free has been changed from "void (*)(PyObject *)" to
171 "void (*)(void *)".
172
173- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
174
Guido van Rossum0986d822002-04-08 01:38:42 +0000175- A type can now inherit its metatype from its base type. Previously,
176 when PyType_Ready() was called, if ob_type was found to be NULL, it
177 was always set to &PyType_Type; now it is set to base->ob_type,
178 where base is tp_base, defaulting to &PyObject_Type.
179
180- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
181
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000182- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
183 functions will be allocated using pymalloc if it is enabled. These
184 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
185 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
186 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
187 PyCore_* family of APIs have been removed.
188
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000189- The "u#" parser marker will now pass through Unicode object as-is
190 without going through the buffer API.
191
Martin v. Löwis7198a522002-01-01 19:59:11 +0000192- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
193
Tim Peters10a3bb52001-12-25 19:07:38 +0000194- An old #define of ANY as void has been removed from pyport.h. This
195 hasn't been used since Python's pre-ANSI days, and the #define has
196 been marked as obsolete since then. SF bug 495548 says it created
197 conflicts with other packages, so keeping it around wasn't harmless.
198
Tim Petersaf8446f2001-12-21 21:36:50 +0000199- Because Python's magic number scheme broke on January 1st, we decided
200 to stop Python development. Thanks for all the fish!
201
Tim Petersfb05db22002-03-11 00:24:00 +0000202- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000203 scheme to a new one. See Python/import.c for details.
204
Tim Petersaf8446f2001-12-21 21:36:50 +0000205New platforms
206
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000207- GNU/Hurd is now supported.
208
Tim Petersaf8446f2001-12-21 21:36:50 +0000209Tests
210
211Windows
212
Tim Peters08e72952002-04-16 20:48:01 +0000213- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
214 of that has been fixed in the installer (disabled Wise's "delete in-
215 use files" uninstall option).
216
Guido van Rossum181e41a2002-04-06 00:23:25 +0000217- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
218
Tim Peters33187922002-04-04 20:02:04 +0000219- The installer now installs Start menu shortcuts under (the local
220 equivalent of) "All Users" when doing an Admin install.
221
Tim Petersfb05db22002-03-11 00:24:00 +0000222- file.truncate([newsize]) now works on Windows for all newsize values.
223 It used to fail if newsize didn't fit in 32 bits, reflecting a
224 limitation of MS _chsize (which is no longer used).
225
Tim Petersab034fa2002-02-01 11:27:43 +0000226- os.waitpid() is now implemented for Windows, and can be used to block
227 until a specified process exits. This is similar to, but not exactly
228 the same as, os.waitpid() on POSIX systems. If you're waiting for
229 a specific process whose pid was obtained from one of the spawn()
230 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000231 See the docs for details. The docs were changed to clarify that
232 spawn functions return, and waitpid requires, a process handle on
233 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000234
Tim Peters11bd9942002-02-01 00:52:29 +0000235- New tempfile.TemporaryFile implementation for Windows: this doesn't
236 need a TemproraryFileWrapper wrapper anymore, and should be immune
237 to a nasty problem: before 2.3, if you got a temp file on Windows, it
238 got wrapped in an object whose close() method first closed the
239 underlying file, then deleted the file. This usually worked fine.
240 However, the spawn family of functions on Windows create (at a low C
241 level) the same set of open files in the spawned process Q as were
242 open in the spawning process P. If a temp file f was among them, then
243 doing f.close() in P first closed P's C-level file handle on f, but Q's
244 C-level file handle on f remained open, so the attempt in P to delete f
245 blew up with a "Permission denied" error (Windows doesn't allow
246 deleting open files). This was surprising, subtle, and difficult to
247 work around.
248
249- The os module now exports all the symbolic constants usable with the
250 low-level os.open() on Windows: the new constants in 2.3 are
251 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
252 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
253 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
254 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
255 (so specify both if you want both; note that neither is useful unless
256 specified with O_CREAT too).
257
Tim Petersaf8446f2001-12-21 21:36:50 +0000258Mac
259
260
Tim Peters909c0912001-12-14 23:16:18 +0000261What's New in Python 2.2 final?
262Release date: 21-Dec-2001
263===============================
264
265Type/class unification and new-style classes
266
Barry Warsaw52acb492001-12-21 20:04:22 +0000267- pickle.py, cPickle: allow pickling instances of new-style classes
268 with a custom metaclass.
269
Tim Peters909c0912001-12-14 23:16:18 +0000270Core and builtins
271
Barry Warsaw52acb492001-12-21 20:04:22 +0000272- weakref proxy object: when comparing, unwrap both arguments if both
273 are proxies.
274
Tim Peters909c0912001-12-14 23:16:18 +0000275Extension modules
276
Barry Warsaw52acb492001-12-21 20:04:22 +0000277- binascii.b2a_base64(): fix a potential buffer overrun when encoding
278 very short strings.
279
280- cPickle: the obscure "fast" mode was suspected of causing stack
281 overflows on the Mac. Hopefully fixed this by setting the recursion
282 limit much smaller. If the limit is too low (it only affects
283 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
284 when compiling cPickle.c (or in pyconfig.h).
285
Tim Peters909c0912001-12-14 23:16:18 +0000286Library
287
Barry Warsaw52acb492001-12-21 20:04:22 +0000288- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
289 close or delete time).
290
291- rfc822.py: fixed a bug where the address '<>' was converted to None
292 instead of an empty string (also fixes the email.Utils module).
293
294- xmlrpclib.py: version 1.0.0; uses precision for doubles.
295
296- test suite: the pickle and cPickle tests were not executing any code
297 when run from the standard regresssion test.
298
Tim Peters909c0912001-12-14 23:16:18 +0000299Tools/Demos
300
301Build
302
303C API
304
305New platforms
306
307Tests
308
309Windows
310
Barry Warsaw52acb492001-12-21 20:04:22 +0000311- distutils package: fixed broken Windows installers (bdist_wininst).
312
313- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
314 instances are deleted at process exit time.
315
316- socket.py: prevent mysterious warnings when socket instances are
317 deleted at process exit time.
318
319- posixmodule.c: fix a Windows crash with stat() of a filename ending
320 in backslash.
321
Tim Peters909c0912001-12-14 23:16:18 +0000322Mac
323
Barry Warsaw52acb492001-12-21 20:04:22 +0000324- The Carbon toolbox modules have been upgraded to Universal Headers
325 3.4, and experimental CoreGraphics and CarbonEvents modules have
326 been added. All only for framework-enabled MacOSX.
327
Tim Peters909c0912001-12-14 23:16:18 +0000328
Tim Peters6272dfd2001-12-13 19:34:00 +0000329What's New in Python 2.2c1?
330Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000331===========================
332
333Type/class unification and new-style classes
334
Barry Warsaw06557452001-12-14 20:47:12 +0000335- Guido's tutorial introduction to the new type/class features has
336 been extensively updated. See
337
338 http://www.python.org/2.2/descrintro.html
339
340 That remains the primary documentation in this area.
341
Guido van Rossum33bab012001-12-05 22:45:48 +0000342- Fixed a leak: instance variables declared with __slots__ were never
343 deleted!
344
Guido van Rossum4b800852001-12-03 00:54:52 +0000345- The "delete attribute" method of descriptor objects is called
346 __delete__, not __del__. In previous releases, it was mistakenly
347 called __del__, which created an unfortunate overloading condition
348 with finalizers. (The "get attribute" and "set attribute" methods
349 are still called __get__ and __set__, respectively.)
350
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000351- Some subtle issues with the super built-in were fixed:
352
353 (a) When super itself is subclassed, its __get__ method would still
354 return an instance of the base class (i.e., of super).
355
356 (b) super(C, C()).__class__ would return C rather than super. This
357 is confusing. To fix this, I decided to change the semantics of
358 super so that it only applies to code attributes, not to data
359 attributes. After all, overriding data attributes is not
360 supported anyway.
361
362 (c) The __get__ method didn't check whether the argument was an
363 instance of the type used in creation of the super instance.
364
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000365- Previously, hash() of an instance of a subclass of a mutable type
366 (list or dictionary) would return some value, rather than raising
367 TypeError. This has been fixed. Also, directly calling
368 dict.__hash__ and list.__hash__ now raises the same TypeError
369 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000370
Guido van Rossumd331cb52001-12-05 19:46:42 +0000371- New-style objects now support deleting their __dict__. This is for
372 all intents and purposes equivalent to assigning a brand new empty
373 dictionary, but saves space if the object is not used further.
374
Tim Petersb3c9af12001-11-17 00:21:57 +0000375Core and builtins
376
Tim Peters3caca232001-12-06 06:23:26 +0000377- -Qnew now works as documented in PEP 238: when -Qnew is passed on
378 the command line, all occurrences of "/" use true division instead
379 of classic division. See the PEP for details. Note that "all"
380 means all instances in library and 3rd-party modules, as well as in
381 your own code. As the PEP says, -Qnew is intended for use only in
382 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000383 Note that test_coercion.py in the standard Python test suite fails
384 under -Qnew; this is expected, and won't be repaired until true
385 division becomes the default (in the meantime, test_coercion is
386 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000387
Fred Drake6c01e252001-12-14 17:08:12 +0000388- complex() now only allows the first argument to be a string
389 argument, and raises TypeError if either the second arg is a string
390 or if the second arg is specified when the first is a string.
391
Tim Petersb3c9af12001-11-17 00:21:57 +0000392Extension modules
393
Martin v. Löwis560da622001-11-24 09:24:51 +0000394- gc.get_referents was renamed to gc.get_referrers.
395
Tim Petersb3c9af12001-11-17 00:21:57 +0000396Library
397
Tim Peters25059d32001-12-07 20:35:43 +0000398- Functions in the os.spawn() family now release the global interpreter
399 lock around calling the platform spawn. They should always have done
400 this, but did not before 2.2c1. Multithreaded programs calling
401 an os.spawn function with P_WAIT will no longer block all Python threads
402 until the spawned program completes. It's possible that some programs
403 relies on blocking, although more likely by accident than by design.
404
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000405- webbrowser defaults to netscape.exe on OS/2 now.
406
Martin v. Löwis652e1912001-11-25 14:50:56 +0000407- Tix.ResizeHandle exposes detach_widget, hide, and show.
408
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000409- The charset alias windows_1252 has been added.
410
Barry Warsaw06557452001-12-14 20:47:12 +0000411- types.StringTypes is a tuple containing the defined string types;
412 usually this will be (str, unicode), but if Python was compiled
413 without Unicode support it will be just (str,).
414
415- The pulldom and minidom modules were synchronized to PyXML.
416
Tim Petersb3c9af12001-11-17 00:21:57 +0000417Tools/Demos
418
Barry Warsaw06557452001-12-14 20:47:12 +0000419- A new script called Tools/scripts/google.py was added, which fires
420 off a search on Google.
421
Tim Petersb3c9af12001-11-17 00:21:57 +0000422Build
423
Barry Warsaw06557452001-12-14 20:47:12 +0000424- Note that release builds of Python should arrange to define the
425 preprocessor symbol NDEBUG on the command line (or equivalent).
426 In the 2.2 pre-release series we tried to define this by magic in
427 Python.h instead, but it proved to cause problems for extension
428 authors. The Unix, Windows and Mac builds now all define NDEBUG in
429 release builds via cmdline (or equivalent) instead. Ports to
430 other platforms should do likewise.
431
Jack Jansen1999ef42001-12-06 21:47:20 +0000432- It is no longer necessary to use --with-suffix when building on a
433 case-insensitive file system (such as Mac OS X HFS+). In the build
434 directory an extension is used, but not in the installed python.
435
Tim Petersb3c9af12001-11-17 00:21:57 +0000436C API
437
Tim Petersf582b822001-12-11 18:51:08 +0000438- New function PyDict_MergeFromSeq2() exposes the builtin dict
439 constructor's logic for updating a dictionary from an iterable object
440 producing key-value pairs.
441
Tim Peterscffed4b2001-11-29 03:26:37 +0000442- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000443 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000444 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
445 dump core in some bad cases. This has been repaired. As a result,
446 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
447 previously went unchallenged.
448
Tim Petersb3c9af12001-11-17 00:21:57 +0000449New platforms
450
451Tests
452
453Windows
454
455Mac
456
Jack Jansenffa260f2001-12-06 21:14:00 +0000457- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
458 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000459
Barry Warsaw06557452001-12-14 20:47:12 +0000460- Changed logic for finding python home in Mac OS X framework Pythons.
461 Now sys.executable points to the executable again, in stead of to
462 the shared library. The latter is used only for locating the python
463 home.
464
465
Tim Peters84362bc2001-10-19 17:55:30 +0000466What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000467Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000468===========================
469
470Type/class unification and new-style classes
471
Guido van Rossum3d27df02001-11-15 20:27:54 +0000472- Multiple inheritance mixing new-style and classic classes in the
473 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000474
475 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000476 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000477
478 The MRO (method resolution order) for each base class is respected
479 according to its kind, but the MRO for the derived class is computed
480 using new-style MRO rules if any base clase is a new-style class.
481 This needs to be documented.
482
Tim Petersa427a2b2001-10-29 22:25:45 +0000483- The new builtin dictionary() constructor, and dictionary type, have
484 been renamed to dict. This reflects a decade of common usage.
485
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000486- dict() now accepts an iterable object producing 2-sequences. For
487 example, dict(d.items()) == d for any dictionary d. The argument,
488 and the elements of the argument, can be any iterable objects.
489
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000490- New-style classes can now have a __del__ method, which is called
491 when the instance is deleted (just like for classic classes).
492
Guido van Rossum12d955c2001-10-26 14:56:06 +0000493- Assignment to object.__dict__ is now possible, for objects that are
494 instances of new-style classes that have a __dict__ (unless the base
495 class forbids it).
496
Guido van Rossumc8e56452001-10-22 00:43:43 +0000497- Methods of built-in types now properly check for keyword arguments
498 (formerly these were silently ignored). The only built-in methods
499 that take keyword arguments are __call__, __init__ and __new__.
500
Guido van Rossum86443212001-10-27 22:28:54 +0000501- The socket function has been converted to a type; see below.
502
Tim Peters84362bc2001-10-19 17:55:30 +0000503Core and builtins
504
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000505- Assignment to __debug__ raises SyntaxError at compile-time. This
506 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000507 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000508
Guido van Rossum12d955c2001-10-26 14:56:06 +0000509- Clarified the error messages for unsupported operands to an operator
510 (like 1 + '').
511
Tim Peters84362bc2001-10-19 17:55:30 +0000512Extension modules
513
Tim Peters5ebfd362001-11-13 23:11:19 +0000514- mmap has a new keyword argument, "access", allowing a uniform way for
515 both Windows and Unix users to create read-only, write-through and
516 copy-on-write memory mappings. This was previously possible only on
517 Unix. A new keyword argument was required to support this in a
518 uniform way because the mmap() signuatures had diverged across
519 platforms. Thanks to Jay T Miller for repairing this!
520
Tim Peters169ded02001-11-03 19:57:21 +0000521- By default, the gc.garbage list now contains only those instances in
522 unreachable cycles that have __del__ methods; in 2.1 it contained all
523 instances in unreachable cycles. "Instances" here has been generalized
524 to include instances of both new-style and old-style classes.
525
Guido van Rossum12d955c2001-10-26 14:56:06 +0000526- The socket module defines a new method for socket objects,
527 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000528 send() until all data has been sent. Also, the socket function has
529 been converted to a subclassable type, like list and tuple (etc.)
530 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000531
532- Various bugfixes to the curses module. There is now a test suite
533 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000534
Guido van Rossum692adf12001-10-30 03:03:03 +0000535- binascii.b2a_base64 no longer places an arbitrary restriction of 57
536 bytes on its input.
537
Tim Peters84362bc2001-10-19 17:55:30 +0000538Library
539
Tim Peters5ebfd362001-11-13 23:11:19 +0000540- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000541 convenience function.
542
Tim Peters75335872001-11-03 19:35:43 +0000543- Symbolic group names in regular expressions must be unique. For
544 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
545 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000546 Python 2.2 detects this error at regexp compilation time;
547 previously, the error went undetected, and results were
548 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
549 pattern.subn() methods have been rewritten in C. Also, an
550 experimental function/method finditer() has been added, which works
551 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000552
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000553- Tix exposes more commands through the classes DirSelectBox,
554 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
555 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
556 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
557
Tim Peters98791af2001-10-23 01:59:54 +0000558- Traceback objects are now scanned by cyclic garbage collection, so
559 cycles created by casual use of sys.exc_info() no longer cause
560 permanent memory leaks (provided garbage collection is enabled).
561
Guido van Rossum49192142001-10-24 20:51:44 +0000562- os.extsep -- a new variable needed by the RISCOS support. It is the
563 separator used by extensions, and is '.' on all platforms except
564 RISCOS, where it is '/'. There is no need to use this variable
565 unless you have a masochistic desire to port your code to RISCOS.
566
Barry Warsaw012852b2001-11-16 16:17:27 +0000567- mimetypes.py has optional support for non-standard, but commonly
568 found types. guess_type() and guess_extension() now accept an
569 optional `strict' flag, defaulting to true, which controls whether
570 recognize non-standard types or not. A few non-standard types we
571 know about have been added. Also, when run as a script, there are
572 new -l and -e options.
573
574- statcache is now deprecated.
575
576- email.Utils.formatdate() now produces the preferred RFC 2822 style
577 dates with numeric timezones (it used to produce obsolete dates
578 hard coded to "GMT" timezone). An optional `localtime' flag is
579 added to produce dates in the local timezone, with daylight savings
580 time properly taken into account.
581
582- In pickle and cPickle, instead of masking errors in load() by
583 transforming them into SystemError, we let the original exception
584 propagate out. Also, implement support for __safe_for_unpickling__
585 in pickle, as it already was supported in cPickle.
586
Tim Peters84362bc2001-10-19 17:55:30 +0000587Tools/Demos
588
589Build
590
Barry Warsaw012852b2001-11-16 16:17:27 +0000591- The dbm module is built using libdb1 if available. The bsddb module
592 is built with libdb3 if available.
593
594- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
595
Tim Peters84362bc2001-10-19 17:55:30 +0000596C API
597
Tim Peters1fc240e2001-10-26 05:06:50 +0000598- New function PySequence_Fast_GET_SIZE() returns the size of a non-
599 NULL result from PySequence_Fast(), more quickly than calling
600 PySequence_Size().
601
Barry Warsaw012852b2001-11-16 16:17:27 +0000602- New argument unpacking function PyArg_UnpackTuple() added.
603
604- New functions PyObject_CallFunctionObjArgs() and
605 PyObject_CallMethodObjArgs() have been added to make it more
606 convenient and efficient to call functions and methods from C.
607
608- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
609 possible that this will propagate errors it didn't before.
610
611- New function PyObject_CheckReadBuffer(), which returns true if its
612 argument supports the single-segment readable buffer interface.
613
Tim Peters84362bc2001-10-19 17:55:30 +0000614New platforms
615
Guido van Rossum86443212001-10-27 22:28:54 +0000616- We've finally confirmed that this release builds on HP-UX 11.00,
617 *with* threads, and passes the test suite.
618
Tim Peters7a33d8b2001-11-05 02:51:07 +0000619- Thanks to a series of patches from Michael Muller, Python may build
620 again under OS/2 Visual Age C++.
621
Guido van Rossum49192142001-10-24 20:51:44 +0000622- Updated RISCOS port by Dietmar Schwertberger.
623
Tim Peters84362bc2001-10-19 17:55:30 +0000624Tests
625
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000626- Added a test script for the curses module. It isn't run automatically;
627 regrtest.py must be run with '-u curses' to enable it.
628
Tim Peters84362bc2001-10-19 17:55:30 +0000629Windows
630
Barry Warsaw012852b2001-11-16 16:17:27 +0000631Mac
632
633- PythonScript has been moved to unsupported and is slated to be
634 removed completely in the next release.
635
636- It should now be possible to build applets that work on both OS9 and
637 OSX.
638
639- The core is now linked with CoreServices not Carbon; as a side
640 result, default 8bit encoding on OSX is now ASCII.
641
642- Python should now build on OSX 10.1.1
643
Tim Peters84362bc2001-10-19 17:55:30 +0000644
Tim Petersabf925f2001-09-28 21:53:42 +0000645What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000646Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000647===========================
648
649Type/class unification and new-style classes
650
Guido van Rossum687ae002001-10-15 22:03:32 +0000651- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000652 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000653 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000654 remains: the __dict__ of a new-style class is a read-only proxy; you
655 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000656 __defined__ attribute of new-style types no longer exists, for lack
657 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000658 future a __cache__ may be resurrected with a similar function, if I
659 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000660
Tim Peters1c9ca872001-10-04 06:43:12 +0000661- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
662 always returned None, even when there was a class docstring).
663
664- doctest now finds and runs docstrings attached to new-style classes,
665 class methods, static methods, and properties.
666
Guido van Rossum9074ef62001-10-16 21:34:49 +0000667Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000668
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000669- A very subtle syntactical pitfall in list comprehensions was fixed.
670 For example: [a+b for a in 'abc', for b in 'def']. The comma in
671 this example is a mistake. Previously, this would silently let 'a'
672 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
673 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
674 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
675 Note that [a for a in <singleton>] is a convoluted way to say
676 [<singleton>] anyway, so it's not like any expressiveness is lost.
677
Guido van Rossum9074ef62001-10-16 21:34:49 +0000678- getattr(obj, name, default) now only catches AttributeError, as
679 documented, rather than returning the default value for all
680 exceptions (which could mask bugs in a __getattr__ hook, for
681 example).
682
Fred Drakecb7a6b52001-10-22 18:41:51 +0000683- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000684 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000685 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000686 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000687
Guido van Rossum1c486092001-10-19 02:05:35 +0000688- unicode(obj) now behaves more like str(obj), accepting arbitrary
689 objects, and calling a __unicode__ method if it exists.
690 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000691 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000692
Barry Warsawf6fb1712001-10-19 05:35:40 +0000693- isinstance() now allows any object as the first argument and a
694 class, a type or something with a __bases__ tuple attribute for the
695 second argument. The second argument may also be a tuple of a
696 class, type, or something with __bases__, in which case isinstance()
697 will return true if the first argument is an instance of any of the
698 things contained in the second argument tuple. E.g.
699
700 isinstance(x, (A, B))
701
702 returns true if x is an instance of A or B.
703
Guido van Rossum9074ef62001-10-16 21:34:49 +0000704Extension modules
705
706- thread.start_new_thread() now returns the thread ID (previously None).
707
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000708- binascii has now two quopri support functions, a2b_qp and b2a_qp.
709
Guido van Rossumc524d952001-10-19 01:31:59 +0000710- readline now supports setting the startup_hook and the
711 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000712
Guido van Rossumc524d952001-10-19 01:31:59 +0000713- os and posix supports chroot(), setgroups() and unsetenv() where
714 available. The stat(), fstat(), statvfs() and fstatvfs() functions
715 now return "pseudo-sequences" -- the various fields can now be
716 accessed as attributes (e.g. os.stat("/").st_mtime) but for
717 backwards compatibility they also behave as a fixed-length sequence.
718 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000719 attributes.
720
721- time: localtime(), gmtime() and strptime() now return a
722 pseudo-sequence similar to the os.stat() return value, with
723 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000724
Guido van Rossum9074ef62001-10-16 21:34:49 +0000725- Decompression objects in the zlib module now accept an optional
726 second parameter to decompress() that specifies the maximum amount
727 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000728
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000729- optional SSL support in the socket module now exports OpenSSL
730 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
731 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000732 automatically seed its PRNG. Also, the keyfile and certfile
733 arguments to socket.ssl() are now optional.
734
735- posixmodule (and by extension, the os module on POSIX platforms) now
736 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000737
Guido van Rossum9074ef62001-10-16 21:34:49 +0000738Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000739
Tim Peters7402f792001-10-02 03:53:41 +0000740- doctest now excludes functions and classes not defined by the module
741 being tested, thanks to Tim Hochberg.
742
Fred Drakecb7a6b52001-10-22 18:41:51 +0000743- HotShot, a new profiler implemented using a C-based callback, has
744 been added. This substantially reduces the overhead of profiling,
745 but it is still quite preliminary. Support modules and
746 documentation will be added in upcoming releases (before 2.2 final).
747
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000748- profile now produces correct output in situations where an exception
749 raised in Python is cleared by C code (e.g. hasattr()). This used
750 to cause wrong output, including spurious claims of recursive
751 functions and attribution of time spent to the wrong function.
752
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000753 The code and documentation for the derived OldProfile and HotProfile
754 profiling classes was removed. The code hasn't worked for years (if
755 you tried to use them, they raised exceptions). OldProfile
756 intended to reproduce the behavior of the profiler Python used more
757 than 7 years ago, and isn't interesting anymore. HotProfile intended
758 to provide a faster profiler (but producing less information), and
759 that's a worthy goal we intend to meet via a different approach (but
760 without losing information).
761
Tim Peterscce092d2001-10-09 05:31:56 +0000762- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000763 a much better system-specific calibration constant. The constant can
764 now be specified in an instance constructor, or as a Profile class or
765 instance variable, instead of by editing profile.py's source code.
766 Calibration must still be done manually (see the docs for the profile
767 module).
768
769 Note that Profile.calibrate() must be overriden by subclasses.
770 Improving the accuracy required exploiting detailed knowledge of
771 profiler internals; the earlier method abstracted away the details
772 and measured a simplified model instead, but consequently computed
773 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000774
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000775- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000776 which indicates whether output is intended for the header 'Q'
777 encoding.
778
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000779- The SocketServer.ThreadingMixIn class now closes the request after
780 finish_request() returns. (Not when it errors out though.)
781
Barry Warsawf6fb1712001-10-19 05:35:40 +0000782- The nntplib module's NNTP.body() method has grown a `file' argument
783 to allow saving the message body to a file.
784
785- The email package has added a class email.Parser.HeaderParser which
786 only parses headers and does not recurse into the message's body.
787 Also, the module/class MIMEAudio has been added for representing
788 audio data (contributed by Anthony Baxter).
789
790- ftplib should be able to handle files > 2GB.
791
792- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
793 ON, and OFF.
794
Fred Drakecb7a6b52001-10-22 18:41:51 +0000795- xml.dom.minidom NodeList objects now support the length attribute
796 and item() method as required by the DOM specifications.
797
Guido van Rossumed554f62001-10-02 23:15:37 +0000798Tools/Demos
799
800- Demo/dns was removed. It no longer serves any purpose; a package
801 derived from it is now maintained by Anthony Baxter, see
802 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000803
Barry Warsawf6fb1712001-10-19 05:35:40 +0000804- The freeze tool has been made more robust, and two new options have
805 been added: -X and -E.
806
Tim Petersabf925f2001-09-28 21:53:42 +0000807Build
808
Barry Warsawf6fb1712001-10-19 05:35:40 +0000809- configure will use CXX in LINKCC if CXX is used to build main() and
810 the system requires to link a C++ main using the C++ compiler.
811
Tim Petersabf925f2001-09-28 21:53:42 +0000812C API
813
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000814- The documentation for the tp_compare slot is updated to require that
815 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
816 not correct. This is not yet enforced but will be enforced in
817 Python 2.3; even later, we may use -2 to indicate errors and +2 for
818 "NotImplemented". Right now, -1 should be used for an error return.
819
Tim Petersd38b1c72001-09-30 05:09:37 +0000820- PyLong_AsLongLong() now accepts int (as well as long) arguments.
821 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
822 as long) arguments.
823
Guido van Rossum3c288632001-10-16 21:13:49 +0000824- PyThread_start_new_thread() now returns a long int giving the thread
825 ID, if one can be calculated; it returns -1 for error, 0 if no
826 thread ID is calculated (this is an incompatible change, but only
827 the thread module used this API). This code has only really been
828 tested on Linux and Windows; other platforms please beware (and
829 report any bugs or strange behavior).
830
Guido van Rossum1c486092001-10-19 02:05:35 +0000831- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
832 input.
833
Tim Petersabf925f2001-09-28 21:53:42 +0000834New platforms
835
836Tests
837
838Windows
839
Tim Peters04cf1d32001-10-09 22:39:40 +0000840- Installer: If you install IDLE, and don't disable file-extension
841 registration, a new "Edit with IDLE" context (right-click) menu entry
842 is created for .py and .pyw files.
843
Tim Peters1ce3cf72001-10-01 17:58:40 +0000844- The signal module now supports SIGBREAK on Windows, thanks to Steven
845 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
846 action remains to call Win32 ExitProcess(). This can be changed via
847 signal.signal(). For example:
848
849 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
850 # (SIGINT) behavior.
851 import signal
852 signal.signal(signal.SIGBREAK,
853 signal.default_int_handler)
854
855 try:
856 while 1:
857 pass
858 except KeyboardInterrupt:
859 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
860 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
861 # program without the possibility for any Python-level cleanup).
862 print "Clean exit"
863
Tim Petersabf925f2001-09-28 21:53:42 +0000864
Tim Petersb07352e2001-09-08 01:25:47 +0000865What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000866Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000867===========================
868
Guido van Rossum808eea72001-09-25 04:15:41 +0000869Type/class unification and new-style classes
870
871- pydoc and inspect are now aware of new-style classes;
872 e.g. help(list) at the interactive prompt now shows proper
873 documentation for all operations on list objects.
874
875- Applications using Jim Fulton's ExtensionClass module can now safely
876 be used with Python 2.2. In particular, Zope 2.4.1 now works with
877 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
878 examples also work again. It is hoped that Gtk and Boost also work
879 with 2.2a4 and beyond. (If you can confirm this, please write
880 webmaster@python.org; if there are still problems, please open a bug
881 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000882
Tim Peters66c1a522001-09-24 21:17:50 +0000883- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
884 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
885 in the constructed property object. fget, fset and fdel weren't
886 discoverable from Python in 2.2a3. __doc__ is new, and allows to
887 associate a docstring with a property.
888
Guido van Rossum808eea72001-09-25 04:15:41 +0000889- Comparison overloading is now more completely implemented. For
890 example, a str subclass instance can properly be compared to a str
891 instance, and it can properly overload comparison. Ditto for most
892 other built-in object types.
893
894- The repr() of new-style classes has changed; instead of <type
895 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
896 *except* for built-in types, which are still rendered as <type
897 'Foo'> (to avoid upsetting existing code that might parse or
898 otherwise rely on repr() of certain type objects).
899
900- The repr() of new-style objects is now always <Foo object at XXX>;
901 previously, it was sometimes <Foo instance at XXX>.
902
903- For new-style classes, what was previously called __getattr__ is now
904 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000905 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000906 one in classic classes is defined which is called only if regular
907 attribute access raises AttributeError; to catch *all* attribute
908 access, you can use __getattribute__ (for new-style classes). If
909 both are defined, __getattribute__ is called first, and if it raises
910 AttributeError, __getattr__ is called.
911
912- The __class__ attribute of new-style objects can be assigned to.
913 The new class must have the same C-level object layout as the old
914 class.
915
916- The builtin file type can be subclassed now. In the usual pattern,
917 "file" is the name of the builtin type, and file() is a new builtin
918 constructor, with the same signature as the builtin open() function.
919 file() is now the preferred way to open a file.
920
921- Previously, __new__ would only see sequential arguments passed to
922 the type in a constructor call; __init__ would see both sequential
923 and keyword arguments. This made no sense whatsoever any more, so
924 now both __new__ and __init__ see all arguments.
925
926- Previously, hash() applied to an instance of a subclass of str or
927 unicode always returned 0. This has been repaired.
928
929- Previously, an operation on an instance of a subclass of an
930 immutable type (int, long, float, complex, tuple, str, unicode),
931 where the subtype didn't override the operation (and so the
932 operation was handled by the builtin type), could return that
933 instance instead a value of the base type. For example, if s was of
934 a str sublass type, s[:] returned s as-is. Now it returns a str
935 with the same value as s.
936
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000937- Provisional support for pickling new-style objects has been added.
938
Guido van Rossum808eea72001-09-25 04:15:41 +0000939Core
940
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000941- file.writelines() now accepts any iterable object producing strings.
942
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000943- PyUnicode_FromEncodedObject() now works very much like
944 PyObject_Str(obj) in that it tries to use __str__/tp_str
945 on the object if the object is not a string or buffer. This
946 makes unicode() behave like str() when applied to non-string/buffer
947 objects.
948
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000949- PyFile_WriteObject now passes Unicode objects to the file's write
950 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000951 of a print statement must support Unicode objects, i.e. they must
952 at least convert them into ASCII strings.
953
Guido van Rossum624c8af2001-09-18 15:21:04 +0000954- Thread scheduling on Solaris should be improved; it is no longer
955 necessary to insert a small sleep at the start of a thread in order
956 to let other runnable threads be scheduled.
957
Tim Petersb07352e2001-09-08 01:25:47 +0000958Library
959
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000960- StringIO.StringIO instances and cStringIO.StringIO instances support
961 read character buffer compatible objects for their .write() methods.
962 These objects are converted to strings and then handled as such
963 by the instances.
964
Barry Warsaw2f600732001-09-24 04:28:10 +0000965- The "email" package has been added. This is basically a port of the
966 mimelib package <http://sf.net/projects/mimelib> with API changes
967 and some implementations updated to use iterators and generators.
968
Tim Peters8a9c2842001-09-22 21:30:22 +0000969- difflib.ndiff() and difflib.Differ.compare() are generators now. This
970 restores the ability of Tools/scripts/ndiff.py to start producing output
971 before the entire comparison is complete.
972
Barry Warsaw58b072d2001-09-22 04:44:21 +0000973- StringIO.StringIO instances and cStringIO.StringIO instances support
974 iteration just like file objects (i.e. their .readline() method is
975 called for each iteration until it returns an empty string).
976
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000977- The codecs module has grown four new helper APIs to access
978 builtin codecs: getencoder(), getdecoder(), getreader(),
979 getwriter().
980
Guido van Rossum624c8af2001-09-18 15:21:04 +0000981- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
982 simplifies writing XML RPC servers.
983
Barry Warsaw647d5e82001-09-28 17:01:02 +0000984- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000985 after interpretation of symbolic links. On non-Unix systems, this
986 is an alias for os.path.abspath().
987
Tim Peters16a77ad2001-09-08 04:00:12 +0000988- operator.indexOf() (PySequence_Index() in the C API) now works with any
989 iterable object.
990
Guido van Rossum624c8af2001-09-18 15:21:04 +0000991- smtplib now supports various authentication and security features of
992 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000993
Guido van Rossum624c8af2001-09-18 15:21:04 +0000994- hmac: a new module implementing keyed hashing for message
995 authentication.
996
997- mimetypes now recognizes more extensions and file types. At the
998 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000999
Guido van Rossum624c8af2001-09-18 15:21:04 +00001000- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001001 Python 2.2 bytecode generation. It has also been promoted from a
1002 Tool to a standard library package. (Tools/compiler still exists as
1003 a sample driver.)
1004
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001005Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001006
Tim Petersb07352e2001-09-08 01:25:47 +00001007Build
1008
Guido van Rossum624c8af2001-09-18 15:21:04 +00001009- Large file support (LFS) is now automatic when the platform supports
1010 it; no more manual configuration tweaks are needed. On Linux, at
1011 least, it's possible to have a system whose C library supports large
1012 files but whose kernel doesn't; in this case, large file support is
1013 still enabled but doesn't do you any good unless you upgrade your
1014 kernel or share your Python executable with another system whose
1015 kernel has large file support.
1016
1017- The configure script now supplies plausible defaults in a
1018 cross-compilation environment. This doesn't mean that the supplied
1019 values are always correct, or that cross-compilation now works
1020 flawlessly -- but it's a first step (and it shuts up most of
1021 autoconf's warnings about AC_TRY_RUN).
1022
1023- The Unix build is now a bit less chatty, courtesy of the parser
1024 generator. The build is completely silent (except for errors) when
1025 using "make -s", thanks to a -q option to setup.py.
1026
Tim Petersb07352e2001-09-08 01:25:47 +00001027C API
1028
Guido van Rossum624c8af2001-09-18 15:21:04 +00001029- The "structmember" API now supports some new flag bits to deny read
1030 and/or write access to attributes in restricted execution mode.
1031
Tim Petersb07352e2001-09-08 01:25:47 +00001032New platforms
1033
Guido van Rossum624c8af2001-09-18 15:21:04 +00001034- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1035 (http://familiar.handhelds.org).
1036
Tim Petersb07352e2001-09-08 01:25:47 +00001037Tests
1038
Tim Peters8a9c2842001-09-22 21:30:22 +00001039- The "classic" standard tests, which work by comparing stdout to
1040 an expected-output file under Lib/test/output/, no longer stop at
1041 the first mismatch. Instead the test is run to completion, and a
1042 variant of ndiff-style comparison is used to report all differences.
1043 This is much easier to understand than the previous style of reporting.
1044
1045- The unittest-based standard tests now use regrtest's test_main()
1046 convention, instead of running as a side-effect of merely being
1047 imported. This allows these tests to be run in more natural and
1048 flexible ways as unittests, outside the regrtest framework.
1049
1050- regrtest.py is much better integrated with unittest and doctest now,
1051 especially in regard to reporting errors.
1052
Tim Petersb07352e2001-09-08 01:25:47 +00001053Windows
1054
Guido van Rossum624c8af2001-09-18 15:21:04 +00001055- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001056 that support it (NTFS under Windows 2000). See "What's New in
1057 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001058
Tim Petersb07352e2001-09-08 01:25:47 +00001059
Tim Petersedc99312001-08-22 21:36:50 +00001060What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001061Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001062===========================
1063
1064Core
1065
Tim Peters9fffa3e2001-09-04 05:14:19 +00001066- Conversion of long to float now raises OverflowError if the long is too
1067 big to represent as a C double.
1068
Tim Peters32f453e2001-09-03 08:35:41 +00001069- The 3-argument builtin pow() no longer allows a third non-None argument
1070 if either of the first two arguments is a float, or if both are of
1071 integer types and the second argument is negative (in which latter case
1072 the arguments are converted to float, so this is really the same
1073 restriction).
1074
Tim Peters5d2b77c2001-09-03 05:47:38 +00001075- The builtin dir() now returns more information, and sometimes much
1076 more, generally naming all attributes of an object, and all attributes
1077 reachable from the object via its class, and from its class's base
1078 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1079 an empty list. In 2.2a3,
1080
1081 >>> dir([])
1082 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1083 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1084 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1085 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1086 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1087 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1088 'reverse', 'sort']
1089
1090 dir(module) continues to return only the module's attributes, though.
1091
Tim Petersbdee63f2001-09-02 03:40:59 +00001092- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001093 than raising OverflowError. This is a partial implementation of PEP
1094 237. You can use -Wdefault::OverflowWarning to enable a warning for
1095 this situation, and -Werror::OverflowWarning to revert to the old
1096 OverflowError exception.
1097
Guido van Rossum61c345f2001-09-04 03:26:15 +00001098- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001099 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001100 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1101 -Qold, meaning the / operator has its classic meaning and no
1102 warnings are issued. Using -Qwarn issues a run-time warning about
1103 all uses of classic division for int and long arguments; -Qwarnall
1104 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001105 (for use with fixdiv.py).
1106 [Note: the remainder of this paragraph (preserved below) became
1107 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1108 <obsolete>
1109 Using -Qnew is questionable; it turns on new division by default, but
1110 only in the __main__ module. You can usefully combine -Qwarn or
1111 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1112 warns about classic division everywhere else.
1113 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001114
Tim Petersbdee63f2001-09-02 03:40:59 +00001115- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001116 long, float, str, unicode, and tuple. (The types complex, list and
1117 dictionary can also be subclassed; this was introduced earlier.)
1118 Note that restrictions apply when subclassing immutable built-in
1119 types: you can only affect the value of the instance by overloading
1120 __new__. You can add mutable attributes, and the subclass instances
1121 will have a __dict__ attribute, but you cannot change the "value"
1122 (as implemented by the base class) of an immutable subclass instance
1123 once it is created.
1124
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001125- The dictionary constructor now takes an optional argument, a
1126 mapping-like object, and initializes the dictionary from its
1127 (key, value) pairs.
1128
Tim Petersbdee63f2001-09-02 03:40:59 +00001129- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001130 "cooperative super calls" in a multiple inheritance setting. For an
1131 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1132
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001133- A new built-in type, property, has been added. This enables the
1134 creation of "properties". These are attributes implemented by
1135 getter and setter functions (or only one of these for read-only or
1136 write-only attributes), without the need to override __getattr__.
1137 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001138
Tim Petersbdee63f2001-09-02 03:40:59 +00001139- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001140 liberalized, to allow leading zeroes. Examples of literals now
1141 legal that were SyntaxErrors before:
1142
1143 00.0 0e3 0100j 07.5 00000000000000000008.
1144
Tim Petersbdee63f2001-09-02 03:40:59 +00001145- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001146 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1147
Tim Petersedc99312001-08-22 21:36:50 +00001148Library
1149
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001150- telnetlib includes symbolic names for the options, and support for
1151 setting an option negotiation callback.
1152
Tim Petersa40c7932001-09-05 22:36:56 +00001153- The new C standard no longer requires that math libraries set errno to
1154 ERANGE on overflow. For platform libraries that exploit this new
1155 freedom, Python's overflow-checking was wholly broken. A new overflow-
1156 checking scheme attempts to repair that, but may not be reliable on all
1157 platforms (C doesn't seem to provide anything both useful and portable
1158 in this area anymore).
1159
Martin v. Löwis44f86962001-09-05 13:44:54 +00001160- Asynchronous timeout actions are available through the new class
1161 threading.Timer.
1162
Tim Peters78526162001-09-05 00:53:45 +00001163- math.log and math.log10 now return sensible results for even huge
1164 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1165
Tim Petersbdee63f2001-09-02 03:40:59 +00001166- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001167 currently held. See the docs for the imp module.
1168
Tim Petersbdee63f2001-09-02 03:40:59 +00001169- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001170 dumps containing ints written on platforms where Python ints are 8 bytes.
1171 When read on a box where Python ints are 4 bytes, such values are
1172 converted to Python longs.
1173
Tim Petersbdee63f2001-09-02 03:40:59 +00001174- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001175 code objects is no longer allowed. This plugs a security hole.
1176
Steve Purcell6091cd62001-09-06 16:05:17 +00001177- unittest.TestResult instances no longer store references to tracebacks
1178 generated by test failures. This prevents unexpected dangling references
1179 to objects that should be garbage collected between tests.
1180
Tim Petersedc99312001-08-22 21:36:50 +00001181Tools
1182
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001183- Tools/scripts/fixdiv.py has been added which can be used to fix
1184 division operators as per PEP 238.
1185
Tim Petersedc99312001-08-22 21:36:50 +00001186Build
1187
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001188- If you are an adventurous person using Mac OS X you may want to look at
1189 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1190 application, which can be used for experimenting with Carbon or Cocoa.
1191 Discussion of this on pythonmac-sig, please.
1192
Tim Peters7eea37e2001-09-04 22:08:56 +00001193C API
1194
1195- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001196
Tim Peters9fffa3e2001-09-04 05:14:19 +00001197- Note that PyLong_AsDouble can fail! This has always been true, but no
1198 callers checked for it. It's more likely to fail now, because overflow
1199 errors are properly detected now. The proper way to check:
1200
1201 double x = PyLong_AsDouble(some_long_object);
1202 if (x == -1.0 && PyErr_Occurred()) {
1203 /* The conversion failed. */
1204 }
1205
Tim Petersbdee63f2001-09-02 03:40:59 +00001206- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001207 compile but will not participate in GC. To upgrade an extension
1208 module:
1209
1210 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001211
Neil Schemenauer4042c692001-08-30 15:38:01 +00001212 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1213 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001214
Neil Schemenauer4042c692001-08-30 15:38:01 +00001215 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1216 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001217
Neil Schemenauer4042c692001-08-30 15:38:01 +00001218 - remove PyGC_HEAD_SIZE from object size calculations
1219
1220 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1221
Tim Petersbdee63f2001-09-02 03:40:59 +00001222- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001223 These can be used safely to construct string objects from a
1224 sprintf-style format string (similar to the format string supported
1225 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001226
Tim Petersedc99312001-08-22 21:36:50 +00001227New platforms
1228
Tim Petersb7da0902001-09-02 23:01:43 +00001229- Stephen Hansen contributed patches sufficient to get a clean compile
1230 under Borland C (Windows), but he reports problems running it and ran
1231 out of time to complete the port. Volunteers? Expect a MemoryError
1232 when importing the types module; this is probably shallow, and
1233 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001234
Tim Petersedc99312001-08-22 21:36:50 +00001235Tests
1236
1237Windows
1238
Tim Peters6e13a562001-09-06 00:32:15 +00001239- Large file support is now enabled on Win32 platforms as well as on
1240 Win64. This means that, for example, you can use f.tell() and f.seek()
1241 to manipulate files larger than 2 gigabytes (provided you have enough
1242 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001243 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1244 filesize limit, and large file support makes no difference there.
1245 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1246 NTFS has no practical limit on file size, and files of any size can be
1247 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001248
Tim Petersbdee63f2001-09-02 03:40:59 +00001249- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001250 points to command.com (patch from Brian Quinlan).
1251
Tim Petersedc99312001-08-22 21:36:50 +00001252
Tim Peters20f51a72001-07-21 02:31:40 +00001253What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001254Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001255===========================
1256
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001257Build
1258
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001259- Tim Peters developed a brand new Windows installer using Wise 8.1,
1260 generously donated to us by Wise Solutions.
1261
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001262- configure supports a new option --enable-unicode, with the values
1263 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1264 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001265
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001266- A new configure option --enable-framework builds a Mac OS X framework,
1267 which "make frameworkinstall" will install. This provides a starting
1268 point for more mac-like functionality, join pythonmac-sig@python.org
1269 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001270
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001271- The NeXT platform is no longer supported.
1272
1273- The `new' module is now statically linked.
1274
Tim Peters0afb6092001-08-15 06:06:44 +00001275Tools
1276
1277- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001278 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001279 the module docstring for details.
1280
Tim Peters20f51a72001-07-21 02:31:40 +00001281Tests
1282
Tim Peters5e824c32001-08-12 22:25:01 +00001283- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001284 platforms, allowing to give clearer test result output. regrtest
1285 also has optional --use/-u switch to run normally disabled tests
1286 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001287
Tim Peters20f51a72001-07-21 02:31:40 +00001288- Several new tests in the standard test suite, with special thanks to
1289 Nick Mathewson.
1290
1291Core
1292
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001293- The floor division operator // has been added as outlined in PEP
1294 238. The / operator still provides classic division (and will until
1295 Python 3.0) unless "from __future__ import division" is included, in
1296 which case the / operator will provide true division. The operator
1297 module provides truediv() and floordiv() functions. Augmented
1298 assignment variants are included, as are the equivalent overloadable
1299 methods and C API methods. See the PEP for a full discussion:
1300 <http://python.sf.net/peps/pep-0238.html>
1301
Tim Peters6cd6a822001-08-17 22:11:27 +00001302- Future statements are now effective in simulated interactive shells
1303 (like IDLE). This should "just work" by magic, but read Michael
1304 Hudson's "Future statements in simulated shells" PEP 264 for full
1305 details: <http://python.sf.net/peps/pep-0264.html>.
1306
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001307- The type/class unification (PEP 252-253) was integrated into the
1308 trunk and is not so tentative any more (the exact specification of
1309 some features is still tentative). A lot of work has done on fixing
1310 bugs and adding robustness and features (performance still has to
1311 come a long way).
1312
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001313- Warnings about a mismatch in the Python API during extension import
1314 now use the Python warning framework (which makes it possible to
1315 write filters for these warnings).
1316
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001317- A function's __dict__ (aka func_dict) will now always be a
1318 dictionary. It used to be possible to delete it or set it to None,
1319 but now both actions raise TypeErrors. It is still legal to set it
1320 to a dictionary object. Getting func.__dict__ before any attributes
1321 have been assigned now returns an empty dictionary instead of None.
1322
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001323- A new command line option, -E, was added which disables the use of
1324 all environment variables, or at least those that are specifically
1325 significant to Python. Usually those have a name starting with
1326 "PYTHON". This was used to fix a problem where the tests fail if
1327 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1328 older distribution.
1329
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001330Library
1331
Tim Peters5e824c32001-08-12 22:25:01 +00001332- New class Differ and new functions ndiff() and restore() in difflib.py.
1333 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001334 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001335
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001336- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1337 value using the minimal quoting required for the value; more
1338 reliable than using xml.sax.saxutils.escape() for attribute values.
1339
1340- Readline completion support for cmd.Cmd was added.
1341
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001342- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1343
1344- Added function threading.BoundedSemaphore()
1345
1346- Added Ka-Ping Yee's cgitb.py module.
1347
1348- The `new' module now exposes the CO_xxx flags.
1349
Martin v. Löwis560da622001-11-24 09:24:51 +00001350- The gc module offers the get_referents function.
1351
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001352New platforms
1353
1354C API
1355
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001356- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1357 which provide a cross-platform implementations for the
1358 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1359 the standard sprintf() and vsprintf() C lib APIs, these versions
1360 apply bounds checking on the used buffer which enhances protection
1361 against buffer overruns.
1362
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001363- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001364 and extensions using different Unicode widths is rendered next to
1365 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001366 will result in an ImportError. Unicode extensions writers must make
1367 sure to check the Unicode width compatibility in their extensions by
1368 using at least one of the mangled Unicode APIs in the extension.
1369
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001370- Two new flags METH_NOARGS and METH_O are available in method definition
1371 tables to simplify implementation of methods with no arguments and a
1372 single untyped argument. Calling such methods is more efficient than
1373 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1374 deprecated.
1375
Tim Petersc1731372001-08-04 08:12:36 +00001376Windows
1377
1378- "import module" now compiles module.pyw if it exists and nothing else
1379 relevant is found.
1380
Tim Peters20f51a72001-07-21 02:31:40 +00001381
Guido van Rossum55a78992001-07-17 17:22:32 +00001382What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001383Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001384===========================
1385
1386Core
Tim Petersa814db52001-05-14 07:05:58 +00001387
Tim Peters6d6c1a32001-08-02 04:15:00 +00001388- TENTATIVELY, a large amount of code implementing much of what's
1389 described in PEP 252 (Making Types Look More Like Classes) and PEP
1390 253 (Subtyping Built-in Types) was added. This will be released
1391 with Python 2.2a1. Documentation will be provided separately
1392 through http://www.python.org/2.2/. The purpose of releasing this
1393 with Python 2.2a1 is to test backwards compatibility. It is
1394 possible, though not likely, that a decision is made not to release
1395 this code as part of 2.2 final, if any serious backwards
1396 incompapatibilities are found during alpha testing that cannot be
1397 repaired.
1398
Guido van Rossum55a78992001-07-17 17:22:32 +00001399- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001400 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001401 more 'yield' statements. See PEP 255. Since this adds a new
1402 keyword to the language, this feature must be enabled by including a
1403 future statement: "from __future__ import generators" (see PEP 236).
1404 Generators will become a standard feature in a future release
1405 (probably 2.3). Without this future statement, 'yield' remains an
1406 ordinary identifier, but a warning is issued each time it is used.
1407 (These warnings currently don't conform to the warnings framework of
1408 PEP 230; we intend to fix this in 2.2a2.)
1409
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001410- The UTF-16 codec was modified to be more RFC compliant. It will now
1411 only remove BOM characters at the start of the string and then
1412 only if running in native mode (UTF-16-LE and -BE won't remove a
1413 leading BMO character).
1414
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001415- Strings now have a new method .decode() to complement the already
1416 existing .encode() method. These two methods provide direct access
1417 to the corresponding decoders and encoders of the registered codecs.
1418
1419 To enhance the usability of the .encode() method, the special
1420 casing of Unicode object return values was dropped (Unicode objects
1421 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001422
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001423 Both methods will now return whatever the codec in charge of the
1424 requested encoding returns as object, e.g. Unicode codecs will
1425 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1426 will return u"äöü"). This enables codec writer to create codecs
1427 for various simple to use conversions.
1428
1429 New codecs were added to demonstrate these new features (the .encode()
1430 and .decode() columns indicate the type of the returned objects):
1431
1432 Name | .encode() | .decode() | Description
1433 ----------------------------------------------------------------------
1434 uu | string | string | UU codec (e.g. for email)
1435 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001436 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001437 zlib | string | string | zlib compression
1438 hex | string | string | 2-byte hex codec
1439 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1440
Mark Hammond2a0af792001-05-14 03:09:36 +00001441- Some operating systems now support the concept of a default Unicode
1442 encoding for file system operations. Notably, Windows supports 'mbcs'
1443 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001444 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001445 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001446
1447 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001448 functions that return filenames (such as os.listdir()) to return Python
1449 string objects pre-encoded using the default file system encoding for
1450 the platform. As this encoding is likely to be different from Python's
1451 default encoding, converting this name to a Unicode object before passing
1452 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001453 would attempt to use its default encoding (generally ASCII) rather than
1454 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001455
Tim Petersa814db52001-05-14 07:05:58 +00001456 In general, this change simply removes surprises when working with
1457 Unicode and the file system, making these operations work as you expect,
1458 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001459 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001460
Tim Peters61dff2b2001-05-08 15:43:37 +00001461- Float (and complex) literals in source code were evaluated to full
1462 precision only when running from a .py file; the same code loaded from a
1463 .pyc (or .pyo) file could suffer numeric differences starting at about the
1464 12th significant decimal digit. For example, on a machine with IEEE-754
1465 floating arithmetic,
1466
1467 x = 9007199254740992.0
1468 print long(x)
1469
1470 printed 9007199254740992 if run directly from .py, but 9007199254740000
1471 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1472 str(float) instead of repr(float) when building code objects. marshal
1473 now uses repr(float) instead, which should reproduce floats to full
1474 machine precision (assuming the platform C float<->string I/O conversion
1475 functions are of good quality).
1476
1477 This may cause floating-point results to change in some cases, and
1478 usually for the better, but may also cause numerically unstable
1479 algorithms to break.
1480
Tim Peters2f228e72001-05-13 00:19:31 +00001481- The implementation of dicts suffers fewer collisions, which has speed
1482 benefits. However, the order in which dict entries appear in dict.keys(),
1483 dict.values() and dict.items() may differ from previous releases for a
1484 given dict. Nothing is defined about this order, so no program should
1485 rely on it. Nevertheless, it's easy to write test cases that rely on the
1486 order by accident, typically because of printing the str() or repr() of a
1487 dict to an "expected results" file. See Lib/test/test_support.py's new
1488 sortdict(dict) function for a simple way to display a dict in sorted
1489 order.
1490
Tim Peters7a3bfc32001-06-12 01:22:22 +00001491- Many other small changes to dicts were made, resulting in faster
1492 operation along the most common code paths.
1493
Guido van Rossum10315822001-05-01 20:54:30 +00001494- Dictionary objects now support the "in" operator: "x in dict" means
1495 the same as dict.has_key(x).
1496
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001497- The update() method of dictionaries now accepts generic mapping
1498 objects. Specifically the argument object must support the .keys()
1499 and __getitem__() methods. This allows you to say, for example,
1500 {}.update(UserDict())
1501
Guido van Rossum10315822001-05-01 20:54:30 +00001502- Iterators were added; this is a generalized way of providing values
1503 to a for loop. See PEP 234. There's a new built-in function iter()
1504 to return an iterator. There's a new protocol to get the next value
1505 from an iterator using the next() method (in Python) or the
1506 tp_iternext slot (in C). There's a new protocol to get iterators
1507 using the __iter__() method (in Python) or the tp_iter slot (in C).
1508 Iterating (i.e. a for loop) over a dictionary generates its keys.
1509 Iterating over a file generates its lines.
1510
Tim Petersf553f892001-05-01 20:45:31 +00001511- The following functions were generalized to work nicely with iterator
1512 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001513 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001514 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1515 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001516 join() method of strings
1517 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001518 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1519 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001520 right-hand side of assignment statements with multiple targets, such as
1521 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001522
Tim Petersd85e1022001-05-11 21:51:48 +00001523- Accessing module attributes is significantly faster (for example,
1524 random.random or os.path or yourPythonModule.yourAttribute).
1525
Tim Peterse63415e2001-05-08 04:38:29 +00001526- Comparing dictionary objects via == and != is faster, and now works even
1527 if the keys and values don't support comparisons other than ==.
1528
Tim Peters95bf9392001-05-10 08:32:44 +00001529- Comparing dictionaries in ways other than == and != is slower: there were
1530 insecurities in the dict comparison implementation that could cause Python
1531 to crash if the element comparison routines for the dict keys and/or
1532 values mutated the dicts. Making the code bulletproof slowed it down.
1533
Tim Peterseb28ef22001-06-02 05:27:19 +00001534- Collisions in dicts are resolved via a new approach, which can help
1535 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001536 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001537 faster now. Thanks to Christian Tismer for pointing out the cause and
1538 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001539
Tim Peters52e155e2001-06-16 05:42:57 +00001540- repr() is much faster for large containers (dict, list, tuple).
1541
1542
Tim Petersa814db52001-05-14 07:05:58 +00001543Library
1544
Fred Drake960fdf92001-07-20 18:38:26 +00001545- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1546 were added to the string module. These a locale-indenpendent
1547 constants, unlike letters, lowercase, and uppercase. These are now
1548 use in appropriate locations in the standard library.
1549
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001550- The flags used in dlopen calls can now be configured using
1551 sys.setdlopenflags and queried using sys.getdlopenflags.
1552
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001553- Fredrik Lundh's xmlrpclib is now a standard library module. This
1554 provides full client-side XML-RPC support. In addition,
1555 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1556 one asyncore-based). Thanks to Eric Raymond for the documentation.
1557
Guido van Rossum643d3912001-07-05 14:46:25 +00001558- The xrange() object is simplified: it no longer supports slicing,
1559 repetition, comparisons, efficient 'in' checking, the tolist()
1560 method, or the start, stop and step attributes. See PEP 260.
1561
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001562- A new function fnmatch.filter to filter lists of file names was added.
1563
Barry Warsawffd674d2001-05-22 16:00:10 +00001564- calendar.py uses month and day names based on the current locale.
1565
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001566- strop is now *really* obsolete (this was announced before with 1.6),
1567 and issues DeprecationWarning when used (except for the four items
1568 that are still imported into string.py).
1569
Tim Petersa814db52001-05-14 07:05:58 +00001570- Cookie.py now sorts key+value pairs by key in output strings.
1571
1572- pprint.isrecursive(object) didn't correctly identify recursive objects.
1573 Now it does.
1574
Tim Peters95b3f782001-05-14 18:39:41 +00001575- pprint functions now much faster for large containers (tuple, list, dict).
1576
Tim Peters7b9542a2001-06-10 23:40:19 +00001577- New 'q' and 'Q' format codes in the struct module, corresponding to C
1578 types "long long" and "unsigned long long" (on Windows, __int64). In
1579 native mode, these can be used only when the platform C compiler supports
1580 these types (when HAVE_LONG_LONG is #define'd by the Python config
1581 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001582 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1583 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001584
Guido van Rossum83213cc2001-06-12 16:48:52 +00001585- The site module installs a new built-in function 'help' that invokes
1586 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1587 it displays a message reminding the user to use 'help()' or
1588 'help(object)'.
1589
Tim Petersa814db52001-05-14 07:05:58 +00001590Tests
1591
1592- New test_mutants.py runs dict comparisons where the key and value
1593 comparison operators mutute the dicts randomly during comparison. This
1594 rapidly causes Python to crash under earlier releases (not for the faint
1595 of heart: it can also cause Win9x to freeze or reboot!).
1596
1597- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001598 pprint.isreadable() return sensible results. Also verifies that simple
1599 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001600
Tim Peters4324aa32001-05-28 22:30:08 +00001601C API
1602
1603- Removed the unused last_is_sticky argument from the internal
1604 _PyTuple_Resize(). If this affects you, you were cheating.
1605
1606
Guido van Rossum55a78992001-07-17 17:22:32 +00001607======================================================================
1608
1609
Guido van Rossumffe13be2001-04-16 18:46:45 +00001610What's New in Python 2.1 (final)?
1611=================================
1612
1613We only changed a few things since the last release candidate, all in
1614Python library code:
1615
1616- A bug in the locale module was fixed that affected locales which
1617 define no grouping for numeric formatting.
1618
1619- A few bugs in the weakref module's implementations of weak
1620 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1621 and the test suite was updated to check for these bugs.
1622
1623- An old bug in the os.path.walk() function (introduced in Python
1624 2.0!) was fixed: a non-existent file would cause an exception
1625 instead of being ignored.
1626
1627- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1628 PyChecker.
1629
1630
Guido van Rossum5b08f132001-04-16 02:05:23 +00001631What's New in Python 2.1c2?
1632===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001633
Guido van Rossum5b08f132001-04-16 02:05:23 +00001634A flurry of small changes, and one showstopper fixed in the nick of
1635time made it necessary to release another release candidate. The list
1636here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001637
Guido van Rossum5b08f132001-04-16 02:05:23 +00001638Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001639
Guido van Rossum5b08f132001-04-16 02:05:23 +00001640- Tim discovered a nasty bug in the dictionary code, caused by
1641 PyDict_Next() calling dict_resize(), and the GC code's use of
1642 PyDict_Next() violating an assumption in dict_items(). This was
1643 fixed with considerable amounts of band-aid, but the net effect is a
1644 saner and more robust implementation.
1645
1646- Made a bunch of symbols static that were accidentally global.
1647
1648Build and Ports
1649
1650- The setup.py script didn't check for a new enough version of zlib
1651 (1.1.3 is needed). Now it does.
1652
1653- Changed "make clean" target to also remove shared libraries.
1654
1655- Added a more general warning about the SGI Irix optimizer to README.
1656
1657Library
1658
1659- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1660 omitted the slash between host and file.html.
1661
1662- The mailbox module's _Mailbox class contained a completely broken
1663 and undocumented seek() method. Ripped it out.
1664
1665- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1666 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1667
1668- Fixed a few last-minute bugs in unittest.
1669
1670Extensions
1671
1672- Reverted the patch to the OpenSSL code in socketmodule.c to support
1673 RAND_status() and the EGD, and the subsequent patch that tried to
1674 fix it for pre-0.9.5 versions; the problem with the patch is that on
1675 some systems it issues a warning whenever socket is imported, and
1676 that's unacceptable.
1677
1678Tests
1679
1680- Fixed the pickle tests to work with "import test.test_pickle".
1681
1682- Tweaked test_locale.py to actually run the test Windows.
1683
1684- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1685 not "wb" (which is not a valid mode at all).
1686
1687- Fix pstats browser crashes. Import readline if it exists to make
1688 the user interface nicer.
1689
1690- Add "import thread" to the top of test modules that import the
1691 threading module (test_asynchat and test_threadedtempfile). This
1692 prevents test failures caused by a broken threading module resulting
1693 from a previously caught failed import.
1694
1695- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1696 needed on some platforms (e.g. Solaris 8) when the tests are run
1697 twice in succession.
1698
1699- Skip rather than fail test_sunaudiodev if no audio device is found.
1700
1701
1702What's New in Python 2.1c1?
1703===========================
1704
1705This list was significantly updated when 2.1c2 was released; the 2.1c1
1706release didn't mention most changes that were actually part of 2.1c1:
1707
1708Legal
1709
1710- Copyright was assigned to the Python Software Foundation (PSF) and a
1711 PSF license (very similar to the CNRI license) was added.
1712
1713- The CNRI copyright notice was updated to include 2001.
1714
1715Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001716
Guido van Rossumc9932722001-04-12 02:31:27 +00001717- After a public outcry, assignment to __debug__ is no longer illegal;
1718 instead, a warning is issued. It will become illegal in 2.2.
1719
Guido van Rossum5b08f132001-04-16 02:05:23 +00001720- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1721 "%#x" now always prepends "0x", even if the value is zero.
1722
1723- Fixed some nits in the bytecode compiler.
1724
1725- Fixed core dumps when calling certain kinds of non-functions.
1726
1727- Fixed various core dumps caused by reference count bugs.
1728
1729Build and Ports
1730
1731- Use INSTALL_SCRIPT to install script files.
1732
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001733- New port: SCO Unixware 7, by Billy G. Allie.
1734
Guido van Rossum5b08f132001-04-16 02:05:23 +00001735- Updated RISCOS port.
1736
1737- Updated BeOS port and notes.
1738
1739- Various other porting problems resolved.
1740
1741Library
1742
1743- The TERMIOS and SOCKET modules are now truly obsolete and
1744 unnecessary. Their symbols are incorporated in the termios and
1745 socket modules.
1746
1747- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1748 better tests for pickling.
1749
1750- threading: make Condition.wait() robust against KeyboardInterrupt.
1751
1752- zipfile: add support to zipfile to support opening an archive
1753 represented by an open file rather than a file name. Fix bug where
1754 the archive was not properly closed. Fixed a bug in this bugfix
1755 where flush() was called for a read-only file.
1756
1757- imputil: added an uninstall() method to the ImportManager.
1758
1759- Canvas: fixed bugs in lower() and tkraise() methods.
1760
1761- SocketServer: API change (added overridable close_request() method)
1762 so that the TCP server can explicitly close the request.
1763
1764- pstats: Eric Raymond added a simple interactive statistics browser,
1765 invoked when the module is run as a script.
1766
1767- locale: fixed a problem in format().
1768
1769- webbrowser: made it work when the BROWSER environment variable has a
1770 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1771 KDE 2. Fixed some other nits.
1772
1773- unittest: changes to allow using a different exception than
1774 AssertionError, and added a few more function aliases. Some other
1775 small changes.
1776
1777- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1778
1779- asynchat: fixed a critical bug in asynchat that slipped through the
1780 2.1b2 release. Fixed another rare bug.
1781
1782- Fix some unqualified except: clauses (always a bad code example).
1783
1784XML
1785
1786- pyexpat: new API get_version_string().
1787
1788- Fixed some minidom bugs.
1789
1790Extensions
1791
1792- Fixed a core dump in _weakref. Removed the weakref.mapping()
1793 function (it adds nothing to the API).
1794
1795- Rationalized the use of header files in the readline module, to make
1796 it compile (albeit with some warnings) with the very recent readline
1797 4.2, without breaking for earlier versions.
1798
1799- Hopefully fixed a buffering problem in linuxaudiodev.
1800
1801- Attempted a fix to make the OpenSSL support in the socket module
1802 work again with pre-0.9.5 versions of OpenSSL.
1803
1804Tests
1805
1806- Added a test case for asynchat and asyncore.
1807
1808- Removed coupling between tests where one test failing could break
1809 another.
1810
1811Tools
1812
1813- Ping added an interactive help browser to pydoc, fixed some nits
1814 in the rest of the pydoc code, and added some features to his
1815 inspect module.
1816
1817- An updated python-mode.el version 4.1 which integrates Ken
1818 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1819 much nicer in XEmacs and Emacs. When stepping through your program
1820 with pdb, in either the shell window or the *Python* window, the
1821 source file and line will be tracked by an arrow. Very cool!
1822
1823- IDLE: syntax warnings in interactive mode are changed into errors.
1824
1825- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001826 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001827
1828- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001829
Barry Warsaw11e89c72001-04-11 20:37:57 +00001830
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001831What's New in Python 2.1 beta 2?
1832================================
1833
Guido van Rossum053ae352001-03-22 14:17:21 +00001834(Unlisted are many fixed bugs, more documentation, etc.)
1835
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001836Core language, builtins, and interpreter
1837
Guido van Rossum053ae352001-03-22 14:17:21 +00001838- The nested scopes work (enabled by "from __future__ import
1839 nested_scopes") is completed; in particular, the future now extends
1840 into code executed through exec, eval() and execfile(), and into the
1841 interactive interpreter.
1842
1843- When calling a base class method (e.g. BaseClass.__init__(self)),
1844 this is now allowed even if self is not strictly spoken a class
1845 instance (e.g. when using metaclasses or the Don Beaudry hook).
1846
1847- Slice objects are now comparable but not hashable; this prevents
1848 dict[:] from being accepted but meaningless.
1849
1850- Complex division is now calculated using less braindead algorithms.
1851 This doesn't change semantics except it's more likely to give useful
1852 results in extreme cases. Complex repr() now uses full precision
1853 like float repr().
1854
1855- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1856
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001857- It is illegal to assign to the name __debug__, which is set when the
1858 interpreter starts. It is effectively a compile-time constant.
1859
1860- A warning will be issued if a global statement for a variable
1861 follows a use or assignment of that variable.
1862
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001863Standard library
1864
Guido van Rossum053ae352001-03-22 14:17:21 +00001865- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1866 inspired by JUnit), is now part of the standard library. You now
1867 have a choice of two testing frameworks: unittest requires you to
1868 write testcases as separate code, doctest gathers them from
1869 docstrings. Both approaches have their advantages and
1870 disadvantages.
1871
1872- A new module Tix was added, which wraps the Tix extension library
1873 for Tk. With that module, it is not necessary to statically link
1874 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1875 require" command. See Demo/tix/.
1876
1877- tzparse.py is now obsolete.
1878
1879- In gzip.py, the seek() and tell() methods are removed -- they were
1880 non-functional anyway, and it's better if callers can test for their
1881 existence with hasattr().
1882
1883Python/C API
1884
1885- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1886 that's already in the dictionary during a PyDict_Next() iteration.
1887 This used to fail occasionally when a dictionary resize operation
1888 could be triggered that would rehash all the keys. All other
1889 modifications to the dictionary are still off-limits during a
1890 PyDict_Next() iteration!
1891
1892- New extended APIs related to passing compiler variables around.
1893
1894- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1895 implement isinstance() and issubclass().
1896
1897- Py_BuildValue() now has a "D" conversion to create a Python complex
1898 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001899
Fred Drake4e262a92001-03-22 18:26:47 +00001900- Extensions types which support weak references must now set the
1901 field allocated for the weak reference machinery to NULL themselves;
1902 this is done to avoid the cost of checking each object for having a
1903 weakly referencable type in PyObject_INIT(), since most types are
1904 not weakly referencable.
1905
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001906- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1907 free variables and cell variables to and from the frame's f_locals.
1908
1909- Variants of several functions defined in pythonrun.h have been added
1910 to support the nested_scopes future statement. The variants all end
1911 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1912 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1913 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001914 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001915
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001916Distutils
1917
1918- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1919 into the release tree.
1920
Tim Peters0e57abf2001-05-02 07:39:38 +00001921- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001922 (an uninstaller, more customization of the installer's display)
1923
1924- from Jack Jansen: added Mac-specific code to generate a dialog for
1925 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001926 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001927 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001928
1929- added 'platforms' and 'keywords' to the set of metadata that can be
1930 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001931
1932- applied patches from Jason Tishler to make the compiler class work with
1933 Cygwin.
1934
1935
Tim Peters2fe289a2001-03-01 22:19:38 +00001936What's New in Python 2.1 beta 1?
1937================================
Tim Petersd66595f2001-02-04 03:09:53 +00001938
1939Core language, builtins, and interpreter
1940
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001941- Following an outcry from the community about the amount of code
1942 broken by the nested scopes feature introduced in 2.1a2, we decided
1943 to make this feature optional, and to wait until Python 2.2 (or at
1944 least 6 months) to make it standard. The option can be enabled on a
1945 per-module basis by adding "from __future__ import nested_scopes" at
1946 the beginning of a module (before any other statements, but after
1947 comments and an optional docstring). See PEP 236 (Back to the
1948 __future__) for a description of the __future__ statement. PEP 227
1949 (Statically Nested Scopes) has been updated to reflect this change,
1950 and to clarify the semantics in a number of endcases.
1951
1952- The nested scopes code, when enabled, has been hardened, and most
1953 bugs and memory leaks in it have been fixed.
1954
1955- Compile-time warnings are now generated for a number of conditions
1956 that will break or change in meaning when nested scopes are enabled:
1957
1958 - Using "from...import *" or "exec" without in-clause in a function
1959 scope that also defines a lambda or nested function with one or
1960 more free (non-local) variables. The presence of the import* or
1961 bare exec makes it impossible for the compiler to determine the
1962 exact set of local variables in the outer scope, which makes it
1963 impossible to determine the bindings for free variables in the
1964 inner scope. To avoid the warning about import *, change it into
1965 an import of explicitly name object, or move the import* statement
1966 to the global scope; to avoid the warning about bare exec, use
1967 exec...in... (a good idea anyway -- there's a possibility that
1968 bare exec will be deprecated in the future).
1969
1970 - Use of a global variable in a nested scope with the same name as a
1971 local variable in a surrounding scope. This will change in
1972 meaning with nested scopes: the name in the inner scope will
1973 reference the variable in the outer scope rather than the global
1974 of the same name. To avoid the warning, either rename the outer
1975 variable, or use a global statement in the inner function.
1976
Neil Schemenauera35c6882001-02-27 04:45:05 +00001977- An optional object allocator has been included. This allocator is
1978 optimized for Python objects and should be faster and use less memory
1979 than the standard system allocator. It is not enabled by default
1980 because of possible thread safety problems. The allocator is only
1981 protected by the Python interpreter lock and it is possible that some
1982 extension modules require a thread safe allocator. The object
1983 allocator can be enabled by providing the "--with-pymalloc" option to
1984 configure.
1985
Tim Petersd66595f2001-02-04 03:09:53 +00001986Standard library
1987
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001988- pyexpat now detects the expat version if expat.h defines it. A
1989 number of additional handlers are provided, which are only available
1990 since expat 1.95. In addition, the methods SetParamEntityParsing and
1991 GetInputContext of Parser objects are available with 1.95.x
1992 only. Parser objects now provide the ordered_attributes and
1993 specified_attributes attributes. A new module expat.model was added,
1994 which offers a number of additional constants if 1.95.x is used.
1995
1996- xml.dom offers the new functions registerDOMImplementation and
1997 getDOMImplementation.
1998
1999- xml.dom.minidom offers a toprettyxml method. A number of DOM
2000 conformance issues have been resolved. In particular, Element now
2001 has an hasAttributes method, and the handling of namespaces was
2002 improved.
2003
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002004- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2005 getting information about live Python code, and pydoc.py, a module
2006 for interactively converting docstrings to HTML or text.
2007 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002008 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002009 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2010 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002011
Tim Peters1eff7962001-03-01 02:31:33 +00002012- New library module difflib.py, primarily packaging the SequenceMatcher
2013 class at the heart of the popular ndiff.py file-comparison tool.
2014
2015- doctest.py (a framework for verifying Python code examples in docstrings)
2016 is now part of the std library.
2017
Tim Petersd66595f2001-02-04 03:09:53 +00002018Windows changes
2019
Guido van Rossume3955a82001-03-02 14:05:59 +00002020- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2021 small GUI that lets you browse the module docstrings using your
2022 default web browser.
2023
Tim Peters1eff7962001-03-01 02:31:33 +00002024- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2025 Platforms) is implemented. See
2026
2027 http://python.sourceforge.net/peps/pep-0235.html
2028
2029 for full details, especially the "Current Lower-Left Semantics" section.
2030 The new Windows import rules are simpler than before:
2031
2032 A. If the PYTHONCASEOK environment variable exists, same as
2033 before: silently accept the first case-insensitive match of any
2034 kind; raise ImportError if none found.
2035
2036 B. Else search sys.path for the first case-sensitive match; raise
2037 ImportError if none found.
2038
2039 The same rules have been implented on other platforms with case-
2040 insensitive but case-preserving filesystems too (including Cygwin, and
2041 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002042
Tim Peters25a9ce32001-02-19 07:06:36 +00002043- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2044 what it's supposed to do (and does do under NT and 2000) via direct
2045 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002046 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002047 all Win9x systems before.
2048
Tim Peters1eff7962001-03-01 02:31:33 +00002049- Build: Subproject _test (effectively) renamed to _testcapi.
2050
Tim Peters2fe289a2001-03-01 22:19:38 +00002051New platforms
2052
2053- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2054 Thanks to Steven Majewski!
2055
2056- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2057 Tishler!
2058
Guido van Rossum9089b272001-03-02 06:49:50 +00002059- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2060 Schwertberger! See RISCOS/README for more information -- it seems
2061 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002062 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002063
Tim Peters25a9ce32001-02-19 07:06:36 +00002064
Tim Petersd7b5e882001-01-25 03:36:26 +00002065What's New in Python 2.1 alpha 2?
2066=================================
Tim Peters40ead762001-01-27 05:35:26 +00002067
Tim Petersd7b5e882001-01-25 03:36:26 +00002068Core language, builtins, and interpreter
2069
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002070- Scopes nest. If a name is used in a function or class, but is not
2071 local, the definition in the nearest enclosing function scope will
2072 be used. One consequence of this change is that lambda statements
2073 could reference variables in the namespaces where the lambda is
2074 defined. In some unusual cases, this change will break code.
2075
2076 In all previous version of Python, names were resolved in exactly
2077 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002078 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002079 function A is defined within a function B, the names bound in B are
2080 not visible in A. The new rules make names bound in B visible in A,
2081 unless A contains a name binding that hides the binding in B.
2082
2083 Section 4.1 of the reference manual describes the new scoping rules
2084 in detail. The test script in Lib/test/test_scope.py demonstrates
2085 some of the effects of the change.
2086
2087 The new rules will cause existing code to break if it defines nested
2088 functions where an outer function has local variables with the same
2089 name as globals or builtins used by the inner function. Example:
2090
2091 def munge(str):
2092 def helper(x):
2093 return str(x)
2094 if type(str) != type(''):
2095 str = helper(str)
2096 return str.strip()
2097
2098 Under the old rules, the name str in helper() is bound to the
2099 builtin function str(). Under the new rules, it will be bound to
2100 the argument named str and an error will occur when helper() is
2101 called.
2102
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002103- The compiler will report a SyntaxError if "from ... import *" occurs
2104 in a function or class scope. The language reference has documented
2105 that this case is illegal, but the compiler never checked for it.
2106 The recent introduction of nested scope makes the meaning of this
2107 form of name binding ambiguous. In a future release, the compiler
2108 may allow this form when there is no possibility of ambiguity.
2109
Tim Peters40ead762001-01-27 05:35:26 +00002110- repr(string) is easier to read, now using hex escapes instead of octal,
2111 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2112
2113 >>> "\texample \r\n" + chr(0) + chr(255)
2114 '\texample \r\n\x00\xff' # in 2.1
2115 '\011example \015\012\000\377' # in 2.0
2116
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002117- Functions are now compared and hashed by identity, not by value, since
2118 the func_code attribute is writable.
2119
Fred Drakefb9d7122001-02-01 20:00:40 +00002120- Weak references (PEP 205) have been added. This involves a few
2121 changes in the core, an extension module (_weakref), and a Python
2122 module (weakref). The weakref module is the public interface. It
2123 includes support for "explicit" weak references, proxy objects, and
2124 mappings with weakly held values.
2125
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002126- A 'continue' statement can now appear in a try block within the body
2127 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002128 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002129
Tim Petersd7b5e882001-01-25 03:36:26 +00002130Standard library
2131
Barry Warsaw30dbd142001-01-31 22:14:01 +00002132- mailbox.py now has a new class, PortableUnixMailbox which is
2133 identical to UnixMailbox but uses a more portable scheme for
2134 determining From_ separators. Also, the constructors for all the
2135 classes in this module have a new optional `factory' argument, which
2136 is a callable used when new message classes must be instantiated by
2137 the next() method.
2138
Tim Petersd7b5e882001-01-25 03:36:26 +00002139- random.py is now self-contained, and offers all the functionality of
2140 the now-deprecated whrandom.py. See the docs for details. random.py
2141 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002142 and restoring the internal state of the generator; and jumpahead(n),
2143 for quickly forcing the internal state to be the same as if n calls to
2144 random() had been made. The latter is particularly useful for multi-
2145 threaded programs, creating one instance of the random.Random() class for
2146 each thread, then using .jumpahead() to force each instance to use a
2147 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002148
Tim Peters0de88fc2001-02-01 04:59:18 +00002149- random.py's seed() function is new. For bit-for-bit compatibility with
2150 prior releases, use the whseed function instead. The new seed function
2151 addresses two problems: (1) The old function couldn't produce more than
2152 about 2**24 distinct internal states; the new one about 2**45 (the best
2153 that can be done in the Wichmann-Hill generator). (2) The old function
2154 sometimes produced identical internal states when passed distinct
2155 integers, and there was no simple way to predict when that would happen;
2156 the new one guarantees to produce distinct internal states for all
2157 arguments in [0, 27814431486576L).
2158
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002159- The socket module now supports raw packets on Linux. The socket
2160 family is AF_PACKET.
2161
Tim Peters9ea17ac2001-02-02 05:57:15 +00002162- test_capi.py is a start at running tests of the Python C API. The tests
2163 are implemented by the new Modules/_testmodule.c.
2164
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002165- A new extension module, _symtable, provides provisional access to the
2166 internal symbol table used by the Python compiler. A higher-level
2167 interface will be added on top of _symtable in a future release.
2168
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002169- Removed the obsolete soundex module.
2170
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002171- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2172 the isSameNode method; NamedNodeMap the get method.
2173
2174- xml.sax.expatreader supports the lexical handler property; it
2175 generates comment, startCDATA, and endCDATA events.
2176
Tim Petersee826f82001-01-31 19:39:44 +00002177Windows changes
2178
2179- Build procedure: the zlib project is built in a different way that
2180 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002181 the zlib binary used. See PCbuild\readme.txt for details. Your old
2182 zlib-related directories can be deleted; you'll need to download fresh
2183 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002184
Tim Peters9ea17ac2001-02-02 05:57:15 +00002185- Build: New subproject _test for the benefit of test_capi.py (see above).
2186
Tim Petersb16c56f2001-02-02 21:24:51 +00002187- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2188 interface to some Python compiler internals).
2189
2190- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002191 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002192
Tim Petersa3a3a032000-11-30 05:22:44 +00002193What's New in Python 2.1 alpha 1?
2194=================================
2195
2196Core language, builtins, and interpreter
2197
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002198- There is a new Unicode companion to the PyObject_Str() API
2199 called PyObject_Unicode(). It behaves in the same way as the
2200 former, but assures that the returned value is an Unicode object
2201 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002202
Guido van Rossumf98eda02001-01-17 15:54:45 +00002203- The comparison operators support "rich comparison overloading" (PEP
2204 207). C extension types can provide a rich comparison function in
2205 the new tp_richcompare slot in the type object. The cmp() function
2206 and the C function PyObject_Compare() first try the new rich
2207 comparison operators before trying the old 3-way comparison. There
2208 is also a new C API PyObject_RichCompare() (which also falls back on
2209 the old 3-way comparison, but does not constrain the outcome of the
2210 rich comparison to a Boolean result).
2211
2212 The rich comparison function takes two objects (at least one of
2213 which is guaranteed to have the type that provided the function) and
2214 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2215 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2216 object, which may be NotImplemented (in which case the tp_compare
2217 slot function is used as a fallback, if defined).
2218
2219 Classes can overload individual comparison operators by defining one
2220 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002221 __ge__. There are no explicit "reflected argument" versions of
2222 these; instead, __lt__ and __gt__ are each other's reflection,
2223 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2224 reflection (similar at the C level). No other implications are
2225 made; in particular, Python does not assume that == is the Boolean
2226 inverse of !=, or that < is the Boolean inverse of >=. This makes
2227 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002228
2229 Classes or types that want to implement (in)equality tests but not
2230 the ordering operators (i.e. unordered types) should implement ==
2231 and !=, and raise an error for the ordering operators.
2232
Guido van Rossuma88479f2001-01-18 14:28:08 +00002233 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002234 Boolean; e.g. a matrix type might want to return a matrix of bits
2235 for A < B, giving elementwise comparisons. Such types should ensure
2236 that any interpretation of their value in a Boolean context raises
2237 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2238 at the C level) to always raise an exception.
2239
Guido van Rossuma88479f2001-01-18 14:28:08 +00002240- Complex numbers use rich comparisons to define == and != but raise
2241 an exception for <, <=, > and >=. Unfortunately, this also means
2242 that cmp() of two complex numbers raises an exception when the two
2243 numbers differ. Since it is not mathematically meaningful to compare
2244 complex numbers except for equality, I hope that this doesn't break
2245 too much code.
2246
Tim Peters3389f192001-02-18 08:48:49 +00002247- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002248 not defined by the language, other than that it's arbitrary but
2249 consistent (see the Reference Manual). An implementation detail changed
2250 in 2.1a1 such that None now compares less than any other object. Code
2251 relying on this new behavior (like code that relied on the previous
2252 behavior) does so at its own risk.
2253
Barry Warsaw573b5412001-01-15 20:43:18 +00002254- Functions and methods now support getting and setting arbitrarily
2255 named attributes (PEP 232). Functions have a new __dict__
2256 (a.k.a. func_dict) which hold the function attributes. Methods get
2257 and set attributes on their underlying im_func. It is a TypeError
2258 to set an attribute on a bound method.
2259
Guido van Rossum051e3352001-01-15 19:11:10 +00002260- The xrange() object implementation has been improved so that
2261 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2262 limitation that in this case len(xrange(sys.maxint)) can't be
2263 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2264 work fine as long as the index i doesn't actually reach 2**31.
2265 (Python uses regular ints for sequence and string indices; fixing
2266 that is much more work.)
2267
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002268- Two changes to from...import:
2269
Guido van Rossumba381232001-02-03 15:06:40 +00002270 1) "from M import X" now works even if (after loading module M)
2271 sys.modules['M'] is not a real module; it's basically a getattr()
2272 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002273
2274 2) "from M import *" now looks for M.__all__ to decide which names to
2275 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2276 filters out names starting with '_' as before. Whether or not
2277 __all__ exists, there's no restriction on the type of M.
2278
Guido van Rossumf61f1662001-01-10 20:13:55 +00002279- File objects have a new method, xreadlines(). This is the fastest
2280 way to iterate over all lines in a file:
2281
2282 for line in file.xreadlines():
2283 ...do something to line...
2284
2285 See the xreadlines module (mentioned below) for how to do this for
2286 other file-like objects.
2287
2288- Even if you don't use file.xreadlines(), you may expect a speedup on
2289 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002290 quite a bit in platform-specific ways: on systems (like Linux) that
2291 support flockfile(), getc_unlocked(), and funlockfile(), those are
2292 used by default. On systems (like Windows) without getc_unlocked(),
2293 a complicated (but still thread-safe) method using fgets() is used by
2294 default.
2295
Tim Petersd52269b2001-01-25 06:23:18 +00002296 You can force use of the fgets() method by #define'ing
2297 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002298 getc_unlocked()).
2299
Tim Petersd52269b2001-01-25 06:23:18 +00002300 You can force fgets() not to be used by #define'ing
2301 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002302 test_bufio.py fails -- and let us know if it does!).
2303
2304- In addition, the fileinput module, while still slower than the other
2305 methods on most platforms, has been sped up too, by using
2306 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002307
2308- Support for run-time warnings has been added, including a new
2309 command line option (-W) to specify the disposition of warnings.
2310 See the description of the warnings module below.
2311
2312- Extensive changes have been made to the coercion code. This mostly
2313 affects extension modules (which can now implement mixed-type
2314 numerical operators without having to use coercion), but
2315 occasionally, in boundary cases the coercion semantics have changed
2316 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002317 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002318 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002319 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002320
Guido van Rossumf98eda02001-01-17 15:54:45 +00002321- In connection with the coercion changes, a new built-in singleton
2322 object, NotImplemented is defined. This can be returned for
2323 operations that wish to indicate they are not implemented for a
2324 particular combination of arguments. From C, this is
2325 Py_NotImplemented.
2326
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002327- The interpreter accepts now bytecode files on the command line even
2328 if they do not have a .pyc or .pyo extension. On Linux, after executing
2329
Martin v. Löwise214baa2001-02-04 22:37:56 +00002330import imp,sys,string
2331magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2332reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2333open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002334
2335 any byte code file can be used as an executable (i.e. as an argument
2336 to execve(2)).
2337
Tim Peters9940b802000-12-01 07:59:35 +00002338- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002339 character. In 1.6 and earlier, they never produced a sign,
2340 and raised an error if the value of the long was too large
2341 to fit in a Python int. In 2.0, they produced a sign if and
2342 only if too large to fit in an int. This was inconsistent
2343 across platforms (because the size of an int varies across
2344 platforms), and inconsistent with hex() and oct(). Example:
2345
2346 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002347 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002348 'ffffffbe' # in 2.0 and before, on 32-bit machines
2349 >>> hex(-0x42L)
2350 '-0x42L' # in all versions of Python
2351
Tim Peters9940b802000-12-01 07:59:35 +00002352 The behavior of %d formats for negative Python longs remains
2353 the same as in 2.0 (although in 1.6 and before, they raised
2354 an error if the long didn't fit in a Python int).
2355
2356 %u formats don't make sense for Python longs, but are allowed
2357 and treated the same as %d in 2.1. In 2.0, a negative long
2358 formatted via %u produced a sign if and only if too large to
2359 fit in an int. In 1.6 and earlier, a negative long formatted
2360 via %u raised an error if it was too big to fit in an int.
2361
Guido van Rossum3661d392000-12-12 22:10:31 +00002362- Dictionary objects have an odd new method, popitem(). This removes
2363 an arbitrary item from the dictionary and returns it (in the form of
2364 a (key, value) pair). This can be useful for algorithms that use a
2365 dictionary as a bag of "to do" items and repeatedly need to pick one
2366 item. Such algorithms normally end up running in quadratic time;
2367 using popitem() they can usually be made to run in linear time.
2368
Tim Peters36cdad12000-12-29 02:06:45 +00002369Standard library
2370
Thomas Woutersfe385252001-01-19 23:16:56 +00002371- In the time module, the time argument to the functions strftime,
2372 localtime, gmtime, asctime and ctime is now optional, defaulting to
2373 the current time (in the local timezone).
2374
Guido van Rossumda91f222001-01-15 16:36:08 +00002375- The ftplib module now defaults to passive mode, which is deemed a
2376 more useful default given that clients are often inside firewalls
2377 these days. Note that this could break if ftplib is used to connect
2378 to a *server* that is inside a firewall, from outside; this is
2379 expected to be a very rare situation. To fix that, you can call
2380 ftp.set_pasv(0).
2381
Martin v. Löwis10a27872001-01-13 09:54:41 +00002382- The module site now treats .pth files not only for path configuration,
2383 but also supports extensions to the initialization code: Lines starting
2384 with import are executed.
2385
Guido van Rossumf61f1662001-01-10 20:13:55 +00002386- There's a new module, warnings, which implements a mechanism for
2387 issuing and filtering warnings. There are some new built-in
2388 exceptions that serve as warning categories, and a new command line
2389 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2390 turns warnings into errors). warnings.warn(message[, category])
2391 issues a warning message; this can also be called from C as
2392 PyErr_Warn(category, message).
2393
2394- A new module xreadlines was added. This exports a single factory
2395 function, xreadlines(). The intention is that this code is the
2396 absolutely fastest way to iterate over all lines in an open
2397 file(-like) object:
2398
2399 import xreadlines
2400 for line in xreadlines.xreadlines(file):
2401 ...do something to line...
2402
2403 This is equivalent to the previous the speed record holder using
2404 file.readlines(sizehint). Note that if file is a real file object
2405 (as opposed to a file-like object), this is equivalent:
2406
2407 for line in file.xreadlines():
2408 ...do something to line...
2409
Tim Peters36cdad12000-12-29 02:06:45 +00002410- The bisect module has new functions bisect_left, insort_left,
2411 bisect_right and insort_right. The old names bisect and insort
2412 are now aliases for bisect_right and insort_right. XXX_right
2413 and XXX_left methods differ in what happens when the new element
2414 compares equal to one or more elements already in the list: the
2415 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002416 right. Code that doesn't care where equal elements end up should
2417 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002418
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002419- The new curses.panel module wraps the panel library that forms part
2420 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2421
Guido van Rossumf61f1662001-01-10 20:13:55 +00002422- The SocketServer module now sets the allow_reuse_address flag by
2423 default in the TCPServer class.
2424
2425- A new function, sys._getframe(), returns the stack frame pointer of
2426 the caller. This is intended only as a building block for
2427 higher-level mechanisms such as string interpolation.
2428
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002429- The pyexpat module supports a number of new handlers, which are
2430 available only in expat 1.2. If invocation of a callback fails, it
2431 will report an additional frame in the traceback. Parser objects
2432 participate now in garbage collection. If expat reports an unknown
2433 encoding, pyexpat will try to use a Python codec; that works only
2434 for single-byte charsets. The parser type objects is exposed as
2435 XMLParserObject.
2436
2437- xml.dom now offers standard definitions for symbolic node type and
2438 exception code constants, and a hierarchy of DOM exceptions. minidom
2439 was adjusted to use them.
2440
2441- The conformance of xml.dom.minidom to the DOM specification was
2442 improved. It detects a number of additional error cases; the
2443 previous/next relationship works even when the tree is modified;
2444 Node supports the normalize() method; NamedNodeMap, DocumentType and
2445 DOMImplementation classes were added; Element supports the
2446 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2447 method.
2448
Guido van Rossumf61f1662001-01-10 20:13:55 +00002449Build issues
2450
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002451- For Unix (and Unix-compatible) builds, configuration and building of
2452 extension modules is now greatly automated. Rather than having to
2453 edit the Modules/Setup file to indicate which modules should be
2454 built and where their include files and libraries are, a
2455 distutils-based setup.py script now takes care of building most
2456 extension modules. All extension modules built this way are built
2457 as shared libraries. Only a few modules that must be linked
2458 statically are still listed in the Setup file; you won't need to
2459 edit their configuration.
2460
2461- Python should now build out of the box on Cygwin. If it doesn't,
2462 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002463
2464- Python now always uses its own (renamed) implementation of getopt()
2465 -- there's too much variation among C library getopt()
2466 implementations.
2467
2468- C++ compilers are better supported; the CXX macro is always set to a
2469 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002470
Tim Petersd92dfe02000-12-12 01:18:41 +00002471Windows changes
2472
2473- select module: By default under Windows, a select() call
2474 can specify no more than 64 sockets. Python now boosts
2475 this Microsoft default to 512. If you need even more than
2476 that, see the MS docs (you'll need to #define FD_SETSIZE
2477 and recompile Python from source).
2478
Guido van Rossumf61f1662001-01-10 20:13:55 +00002479- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2480 subdirectory is no more!
2481
Tim Petersa3a3a032000-11-30 05:22:44 +00002482
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002483What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002484=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002485
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002486Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002487changes are in the file HISTORY. If you are making the jump directly
2488from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2489HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002490
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002491Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2492the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2493http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002494
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002495--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002496
2497======================================================================
2498
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002499What's new in 2.0 (since release candidate 1)?
2500==============================================
2501
2502Standard library
2503
2504- The copy_reg module was modified to clarify its intended use: to
2505 register pickle support for extension types, not for classes.
2506 pickle() will raise a TypeError if it is passed a class.
2507
2508- Fixed a bug in gettext's "normalize and expand" code that prevented
2509 it from finding an existing .mo file.
2510
2511- Restored support for HTTP/0.9 servers in httplib.
2512
Tim Peters989b7b92000-10-16 20:24:53 +00002513- The math module was changed to stop raising OverflowError in case of
2514 underflow, and return 0 instead in underflow cases. Whether Python
2515 used to raise OverflowError in case of underflow was platform-
2516 dependent (it did when the platform math library set errno to ERANGE
2517 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002518
2519- Fixed a bug in StringIO that occurred when the file position was not
2520 at the end of the file and write() was called with enough data to
2521 extend past the end of the file.
2522
2523- Fixed a bug that caused Tkinter error messages to get lost on
2524 Windows. The bug was fixed by replacing direct use of
2525 interp->result with Tcl_GetStringResult(interp).
2526
2527- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2528 redirect response.
2529
2530- Several changes were made to distutils: Some debugging code was
2531 removed from util. Fixed the installer used when an external zip
2532 program (like WinZip) is not found; the source code for this
2533 installer is in Misc/distutils. check_lib() was modified to behave
2534 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2535 test for whether installed modules are on sys.path was changed to
2536 use both normcase() and normpath().
2537
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002538- Several minor bugs were fixed in the xml package (the minidom,
2539 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002540
2541- The regression test driver (regrtest.py) behavior when invoked with
2542 -l changed: It now reports a count of objects that are recognized as
2543 garbage but not freed by the garbage collector.
2544
Tim Peters989b7b92000-10-16 20:24:53 +00002545- The regression test for the math module was changed to test
2546 exceptional behavior when the test is run in verbose mode. Python
2547 cannot yet guarantee consistent exception behavior across platforms,
2548 so the exception part of test_math is run only in verbose mode, and
2549 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002550
2551Internals
2552
2553- PyOS_CheckStack() has been disabled on Win64, where it caused
2554 test_sre to fail.
2555
2556Build issues
2557
2558- Changed compiler flags, so that gcc is always invoked with -Wall and
2559 -Wstrict-prototypes. Users compiling Python with GCC should see
2560 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002561 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002562 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002563
Tim Petersa3a3a032000-11-30 05:22:44 +00002564- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002565
2566Tools and other miscellany
2567
2568- The compiler in Tools/compiler was updated to support the new
2569 language features introduced in 2.0: extended print statement, list
2570 comprehensions, and augmented assignments. The new compiler should
2571 also be backwards compatible with Python 1.5.2; the compiler will
2572 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002573 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002574
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002575What's new in 2.0 release candidate 1 (since beta 2)?
2576=====================================================
2577
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002578What is release candidate 1?
2579
2580We believe that release candidate 1 will fix all known bugs that we
2581intend to fix for the 2.0 final release. This release should be a bit
2582more stable than the previous betas. We would like to see even more
2583widespread testing before the final release, so we are producing this
2584release candidate. The final release will be exactly the same unless
2585any show-stopping (or brown bag) bugs are found by testers of the
2586release candidate.
2587
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002588All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002589to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002590
2591Core language, builtins, and interpreter
2592
2593- A bug that caused crashes when __coerce__ was used with augmented
2594 assignment, e.g. +=, was fixed.
2595
2596- Raise ZeroDivisionError when raising zero to a negative number,
2597 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2598 power operator and the result of math.pow(0.0, -2.0) will vary by
2599 platform. On Linux, it raises a ValueError.
2600
2601- A bug in Unicode string interpolation was fixed that occasionally
2602 caused errors with formats including "%%". For example, the
2603 following expression "%% %s" % u"abc" no longer raises a TypeError.
2604
2605- Compilation of deeply nested expressions raises MemoryError instead
2606 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2607
2608- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2609 rendering them useless. They are now written in binary mode again.
2610
2611Standard library
2612
2613- Keyword arguments are now accepted for most pattern and match object
2614 methods in SRE, the standard regular expression engine.
2615
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002616- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002617 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002618
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002619- Several bugs in the Unicode handling and error handling in _tkinter
2620 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002621
2622- Fix memory management errors in Merge() and Tkapp_Call() routines.
2623
2624- Several changes were made to cStringIO to make it compatible with
2625 the file-like object interface and with StringIO. If operations are
2626 performed on a closed object, an exception is raised. The truncate
2627 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002628 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002629
2630- There were many changes made to the linuxaudiodev module and its
2631 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002632 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002633
2634 Note that this module is named poorly, because it should work
2635 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002636 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002637
2638 The module now raises exceptions when errors occur instead of
2639 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2640 audio) and defines a getptr() method that calls the
2641 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2642
2643- The library_version attribute, introduced in an earlier beta, was
2644 removed because it can not be supported with early versions of the C
2645 readline library, which provides no way to determine the version at
2646 compile-time.
2647
2648- The binascii module is now enabled on Win64.
2649
Tim Peters46446d62000-10-09 21:19:31 +00002650- tokenize.py no longer suffers "recursion depth" errors when parsing
2651 programs with very long string literals.
2652
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002653Internals
2654
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002655- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002656 which is called when the interpreter starts up to determine where
2657 the standard library is installed. These vulnerabilities affect all
2658 previous versions of Python and can be exploited by setting very
2659 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2660 setuid Python script, although use of the wrapper in
2661 Misc/setuid-prog.c will eliminate the vulnerability.
2662
2663- Fixed garbage collection bugs in instance creation that were
2664 triggered when errors occurred during initialization. The solution,
2665 applied in cPickle and in PyInstance_New(), is to call
2666 PyObject_GC_Init() after the initialization of the object's
2667 container attributes is complete.
2668
2669- pyexpat adds definitions of PyModule_AddStringConstant and
2670 PyModule_AddObject if the Python version is less than 2.0, which
2671 provides compatibility with PyXML on Python 1.5.2.
2672
2673- If the platform has a bogus definition for LONG_BIT (the number of
2674 bits in a long), an error will be reported at compile time.
2675
2676- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2677 collection crashes and possibly other, unreported crashes.
2678
2679- Fixed a memory leak in _PyUnicode_Fini().
2680
2681Build issues
2682
2683- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002684 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002685 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002686
2687- The mmap.PAGESIZE constant is now initialized using sysconf when
2688 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2689
2690- The md5 file should now compile on all platforms.
2691
2692- The select module now compiles on platforms that do not define
2693 POLLRDNORM and related constants.
2694
2695- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002696 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002697
Jeremy Hylton10921202000-10-09 18:34:12 +00002698- BeOS: A number of changes were made to the build and installation
2699 process. ar-fake now operates on a directory of object files.
2700 dl_export.h is gone, and its macros now appear on the mwcc command
2701 line during build on PPC BeOS.
2702
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002703- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002704 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002705
2706- Cygwin: Support for shared libraries, Tkinter, and sockets.
2707
2708- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2709
2710Tools and other miscellany
2711
2712- Removed debugging prints from main used with freeze.
2713
Tim Peters46446d62000-10-09 21:19:31 +00002714- IDLE auto-indent no longer crashes when it encounters Unicode
2715 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002716
2717What's new in 2.0 beta 2 (since beta 1)?
2718========================================
2719
2720Core language, builtins, and interpreter
2721
Tim Peters482c0212000-09-26 06:33:09 +00002722- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002723 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002724
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002725- Add -h and -V command line options to print the usage message and
2726 Python version number and exit immediately.
2727
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002728- eval() and exec accept Unicode objects as code parameters.
2729
2730- getattr() and setattr() now also accept Unicode objects for the
2731 attribute name, which are converted to strings using the default
2732 encoding before lookup.
2733
2734- Multiplication on string and Unicode now does proper bounds
2735 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2736 string is too long."
2737
2738- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002739 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002740
Jeremy Hylton1b618592000-09-26 05:32:36 +00002741
2742Standard library and extensions
2743
Guido van Rossum5b08f132001-04-16 02:05:23 +00002744- socket module: the OpenSSL code now adds support for RAND_status()
2745 and EGD (Entropy Gathering Device).
2746
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002747- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002748 argument checking; it still takes no arguments.
2749
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002750- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002751
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002752- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002753
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002754- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002755
2756- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002757 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002758
2759- copy: Copy Unicode objects atomically.
2760
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002761- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002762
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002763- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002764
Fred Drake67233bc2000-09-26 16:40:27 +00002765- dbm: Add get() and setdefault() methods to dbm object. Add constant
2766 `library' to module that names the library used. Added doc strings
2767 and method names to error messages. Uses configure to determine
2768 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2769 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002770
2771- distutils: Update to version 0.9.3.
2772
2773- dl: Add several dl.RTLD_ constants.
2774
2775- fpectl: Now supported on FreeBSD.
2776
2777- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2778 found by the collector will be saved in gc.garbage. This is useful
2779 for debugging a program that creates reference cycles.
2780
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002781- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002782 of HTTP class. Do not close socket on zero-length response. Do not
2783 crash when server sends invalid content-length header.
2784
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002785- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002786
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002787- marshal: When reading a short, sign-extend on platforms where shorts
2788 are bigger than 16 bits. When reading a long, repair the unportable
2789 sign extension that was being done for 64-bit machines. (It assumed
2790 that signed right shift sign-extends.)
2791
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792- operator: Add contains(), invert(), __invert__() as aliases for
2793 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002794
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002795- os: Add support for popen2() and popen3() on all platforms where
2796 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002797
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002798- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002799 clicking on a file in Explorer (or passing the file name to the
2800 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002801
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002802- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002803 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002804
2805- pickle: Now raises ValueError when an invalid pickle that contains
2806 a non-string repr where a string repr was expected. This behavior
2807 matches cPickle.
2808
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002809- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002810
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002811- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002812
2813- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002814 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002815 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002816
2817- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002818 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002819
2820- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002821 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002822 few cycles during startup since the first call to
2823 setdefaultencoding() will initialize the codec registry and the
2824 encodings package.
2825
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002826- socket: Support for size hint in readlines() method of object returned
2827 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002828
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002829- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002830 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002831 is followed by whitespace.
2832
Tim Petersa3a3a032000-11-30 05:22:44 +00002833- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002834
2835- struct: Check ranges for bytes and shorts.
2836
2837- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002838 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
2840- Tkinter: Image objects are now guaranteed to have unique ids. Set
2841 event.delta to zero if Tk version doesn't support mousewheel.
2842 Removed some debugging prints.
2843
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002844- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002845
Fred Drake67233bc2000-09-26 16:40:27 +00002846- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002847 which works around a bug in Norton AntiVirus 2000 that leads directly
2848 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002849
2850- xml: New version detection code allows PyXML to override standard
2851 XML package if PyXML version is greater than 0.6.1.
2852
Fred Drake64bb3802000-09-26 16:21:35 +00002853- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2854 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2855 tree only for nodes which are sufficiently interesting to a specific
2856 application. Does not provide the HTML-specific extensions. Still
2857 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002858
Fred Drake64bb3802000-09-26 16:21:35 +00002859- xml.sax: SAX 2 support for Python, including all the handler
2860 interfaces needed to process XML 1.0 compliant XML. Some
2861 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002862
Fred Drake64bb3802000-09-26 16:21:35 +00002863- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2864 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002865
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002866
Jeremy Hylton1b618592000-09-26 05:32:36 +00002867C API
2868
2869- Add three new convenience functions for module initialization --
2870 PyModule_AddObject(), PyModule_AddIntConstant(), and
2871 PyModule_AddStringConstant().
2872
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002873- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874 removed and add #error to Python.h if NULL isn't defined after
2875 #include of stdio.h.
2876
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002877- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878 backwards compatibility (at the source level) with old extensions.
2879
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002880- A wrapper API was added for signal() and sigaction(). Instead of
2881 either function, always use PyOS_getsig() to get a signal handler
2882 and PyOS_setsig() to set one. A new convenience typedef
2883 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002884
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002885- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002886 internal data buffer and size of a string object -- or the default
2887 encoded version of a Unicode object.
2888
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002889- PyString_Size() and PyString_AsString() accept Unicode objects.
2890
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002891- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002892 exists). INT_MAX and LONG_MAX will always be defined, even if
2893 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002894
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002895- PyFloat_FromString takes a second argument, pend, that was
2896 effectively useless. It is now officially useless but preserved for
2897 backwards compatibility. If the pend argument is not NULL, *pend is
2898 set to NULL.
2899
2900- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2901 for the attribute name. See note on getattr() above.
2902
2903- A few bug fixes to argument processing for Unicode.
2904 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2905 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2906 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002907 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002908
2909- Py_BuildValue accepts B format (for bgen-generated code).
2910
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002911
Jeremy Hylton1b618592000-09-26 05:32:36 +00002912Internals
2913
2914- On Unix, fix code for finding Python installation directory so that
2915 it works when argv[0] is a relative path.
2916
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002917- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002918 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002919 rather than by generating a copy of the object.
2920
Tim Peters482c0212000-09-26 06:33:09 +00002921- Several of the internal Unicode tables are much smaller now, and
2922 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002923
Jeremy Hylton97693b02000-09-26 17:42:51 +00002924- In the garbage collector: Fixed bug in collection of tuples. Fixed
2925 bug that caused some instances to be removed from the container set
2926 while they were still live. Fixed parsing in gc.set_debug() for
2927 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002928
2929- Fixed refcount problem in instance deallocation that only occurred
2930 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2931
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002932- On Windows, getpythonregpath is now protected against null data in
2933 registry key.
2934
2935- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002936 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002937
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002938
Jeremy Hylton1b618592000-09-26 05:32:36 +00002939Build and platform-specific issues
2940
2941- Better support of GNU Pth via --with-pth configure option.
2942
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002943- Python/C API now properly exposed to dynamically-loaded extension
2944 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002945
2946- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2947 Don't define MS_SYNC to be zero when it is undefined. Added missing
2948 prototypes in posixmodule.c.
2949
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002950- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002951 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002952
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002953- Fix largefile support on older NetBSD systems and OpenBSD by adding
2954 define for TELL64.
2955
2956
2957Tools and other miscellany
2958
2959- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2960
2961- freeze: The modulefinder now works with 2.0 opcodes.
2962
Tim Petersa3a3a032000-11-30 05:22:44 +00002963- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002964 Move hackery of sys.argv until after the Tk instance has been
2965 created, which allows the application-specific Tkinter
2966 initialization to be executed if present; also pass an explicit
2967 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002968
Jeremy Hylton1b618592000-09-26 05:32:36 +00002969
2970What's new in 2.0 beta 1?
2971=========================
2972
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002973Source Incompatibilities
2974------------------------
2975
2976None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2977such as single-argument append(), connect() and bind(), and changes to
2978str(long) and repr(float).
2979
2980
2981Binary Incompatibilities
2982------------------------
2983
2984- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2985with Python 2.0; these extensions will have to be rebuilt for Python
29862.0.
2987
2988- On Windows, attempting to import a third party extension built for
2989Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2990can do about this. Check your PYTHONPATH environment variable!
2991
2992- Python bytecode files (*.pyc and *.pyo) are not compatible between
2993releases.
2994
2995
2996Overview of Changes Since 1.6
2997-----------------------------
2998
2999There are many new modules (including brand new XML support through
3000the xml package, and i18n support through the gettext module); a list
3001of all new modules is included below. Lots of bugs have been fixed.
3002
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003003The process for making major new changes to the language has changed
3004since Python 1.6. Enhancements must now be documented by a Python
3005Enhancement Proposal (PEP) before they can be accepted.
3006
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003007There are several important syntax enhancements, described in more
3008detail below:
3009
3010 - Augmented assignment, e.g. x += 1
3011
3012 - List comprehensions, e.g. [x**2 for x in range(10)]
3013
3014 - Extended import statement, e.g. import Module as Name
3015
3016 - Extended print statement, e.g. print >> file, "Hello"
3017
3018Other important changes:
3019
3020 - Optional collection of cyclical garbage
3021
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003022Python Enhancement Proposal (PEP)
3023---------------------------------
3024
3025PEP stands for Python Enhancement Proposal. A PEP is a design
3026document providing information to the Python community, or describing
3027a new feature for Python. The PEP should provide a concise technical
3028specification of the feature and a rationale for the feature.
3029
3030We intend PEPs to be the primary mechanisms for proposing new
3031features, for collecting community input on an issue, and for
3032documenting the design decisions that have gone into Python. The PEP
3033author is responsible for building consensus within the community and
3034documenting dissenting opinions.
3035
3036The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003037
3038Augmented Assignment
3039--------------------
3040
3041This must have been the most-requested feature of the past years!
3042Eleven new assignment operators were added:
3043
Guido van Rossume905e952000-09-05 12:42:46 +00003044 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003045
3046For example,
3047
3048 A += B
3049
3050is similar to
3051
3052 A = A + B
3053
3054except that A is evaluated only once (relevant when A is something
3055like dict[index].attr).
3056
3057However, if A is a mutable object, A may be modified in place. Thus,
3058if A is a number or a string, A += B has the same effect as A = A+B
3059(except A is only evaluated once); but if a is a list, A += B has the
3060same effect as A.extend(B)!
3061
3062Classes and built-in object types can override the new operators in
3063order to implement the in-place behavior; the not-in-place behavior is
3064used automatically as a fallback when an object doesn't implement the
3065in-place behavior. For classes, the method name is derived from the
3066method name for the corresponding not-in-place operator by inserting
3067an 'i' in front of the name, e.g. __iadd__ implements in-place
3068__add__.
3069
3070Augmented assignment was implemented by Thomas Wouters.
3071
3072
3073List Comprehensions
3074-------------------
3075
3076This is a flexible new notation for lists whose elements are computed
3077from another list (or lists). The simplest form is:
3078
3079 [<expression> for <variable> in <sequence>]
3080
Guido van Rossum56db0952000-09-06 23:34:25 +00003081For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003082This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003083
3084You can also add a condition:
3085
3086 [<expression> for <variable> in <sequence> if <condition>]
3087
3088For example, [w for w in words if w == w.lower()] would yield the list
3089of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003090than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003091
3092You can also have nested for loops and more than one 'if' clause. For
3093example, here's a function that flattens a sequence of sequences::
3094
3095 def flatten(seq):
3096 return [x for subseq in seq for x in subseq]
3097
3098 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3099
3100This prints
3101
3102 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3103
3104List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003105Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003106
3107
3108Extended Import Statement
3109-------------------------
3110
3111Many people have asked for a way to import a module under a different
3112name. This can be accomplished like this:
3113
3114 import foo
3115 bar = foo
3116 del foo
3117
3118but this common idiom gets old quickly. A simple extension of the
3119import statement now allows this to be written as follows:
3120
3121 import foo as bar
3122
3123There's also a variant for 'from ... import':
3124
3125 from foo import bar as spam
3126
3127This also works with packages; e.g. you can write this:
3128
3129 import test.regrtest as regrtest
3130
3131Note that 'as' is not a new keyword -- it is recognized only in this
3132context (this is only possible because the syntax for the import
3133statement doesn't involve expressions).
3134
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003135Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003136
3137
3138Extended Print Statement
3139------------------------
3140
3141Easily the most controversial new feature, this extension to the print
3142statement adds an option to make the output go to a different file
3143than the default sys.stdout.
3144
3145For example, to write an error message to sys.stderr, you can now
3146write:
3147
3148 print >> sys.stderr, "Error: bad dog!"
3149
3150As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003151evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003152
3153 print >> None, "Hello world"
3154
3155is equivalent to
3156
3157 print "Hello world"
3158
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003159Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003160
3161
3162Optional Collection of Cyclical Garbage
3163---------------------------------------
3164
3165Python is now equipped with a garbage collector that can hunt down
3166cyclical references between Python objects. It's no replacement for
3167reference counting; in fact, it depends on the reference counts being
3168correct, and decides that a set of objects belong to a cycle if all
3169their reference counts can be accounted for from their references to
3170each other. This devious scheme was first proposed by Eric Tiedemann,
3171and brought to implementation by Neil Schemenauer.
3172
3173There's a module "gc" that lets you control some parameters of the
3174garbage collection. There's also an option to the configure script
3175that lets you enable or disable the garbage collection. In 2.0b1,
3176it's on by default, so that we (hopefully) can collect decent user
3177experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003178performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003179off by default in the final 2.0 release.
3180
3181
3182Smaller Changes
3183---------------
3184
3185A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3186map(None, seq1, seq2, ...) when the sequences have the same length;
3187i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3188the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003189zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003190
3191sys.version_info is a tuple (major, minor, micro, level, serial).
3192
3193Dictionaries have an odd new method, setdefault(key, default).
3194dict.setdefault(key, default) returns dict[key] if it exists; if not,
3195it sets dict[key] to default and returns that value. Thus:
3196
3197 dict.setdefault(key, []).append(item)
3198
3199does the same work as this common idiom:
3200
3201 if not dict.has_key(key):
3202 dict[key] = []
3203 dict[key].append(item)
3204
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003205There are two new variants of SyntaxError that are raised for
3206indentation-related errors: IndentationError and TabError.
3207
3208Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3209escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003210
3211The limits on the size of expressions and file in Python source code
3212have been raised from 2**16 to 2**32. Previous versions of Python
3213were limited because the maximum argument size the Python VM accepted
3214was 2**16. This limited the size of object constructor expressions,
3215e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3216limit was raised thanks to a patch by Charles Waldman that effectively
3217fixes the problem. It is now much more likely that you will be
3218limited by available memory than by an arbitrary limit in Python.
3219
3220The interpreter's maximum recursion depth can be modified by Python
3221programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3222limit is the maximum number of recursive calls that can be made by
3223Python code. The limit exists to prevent infinite recursion from
3224overflowing the C stack and causing a core dump. The default value is
32251000. The maximum safe value for a particular platform can be found
3226by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003227
3228New Modules and Packages
3229------------------------
3230
3231atexit - for registering functions to be called when Python exits.
3232
3233imputil - Greg Stein's alternative API for writing custom import
3234hooks.
3235
3236pyexpat - an interface to the Expat XML parser, contributed by Paul
3237Prescod.
3238
3239xml - a new package with XML support code organized (so far) in three
3240subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3241would fill a volume. There's a special feature whereby a
3242user-installed package named _xmlplus overrides the standard
3243xmlpackage; this is intended to give the XML SIG a hook to distribute
3244backwards-compatible updates to the standard xml package.
3245
3246webbrowser - a platform-independent API to launch a web browser.
3247
3248
Guido van Rossume905e952000-09-05 12:42:46 +00003249Changed Modules
3250---------------
3251
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003252array -- new methods for array objects: count, extend, index, pop, and
3253remove
3254
3255binascii -- new functions b2a_hex and a2b_hex that convert between
3256binary data and its hex representation
3257
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003258calendar -- Many new functions that support features including control
3259over which day of the week is the first day, returning strings instead
3260of printing them. Also new symbolic constants for days of week,
3261e.g. MONDAY, ..., SUNDAY.
3262
3263cgi -- FieldStorage objects have a getvalue method that works like a
3264dictionary's get method and returns the value attribute of the object.
3265
3266ConfigParser -- The parser object has new methods has_option,
3267remove_section, remove_option, set, and write. They allow the module
3268to be used for writing config files as well as reading them.
3269
3270ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003271optionally support the RFC 959 REST command.
3272
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003273gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003274
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003275httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3276the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003277
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003278locale -- implement getdefaultlocale for Win32 and Macintosh
3279
3280marshal -- no longer dumps core when marshaling deeply nested or
3281recursive data structures
3282
3283os -- new functions isatty, seteuid, setegid, setreuid, setregid
3284
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003285os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3286support under Unix.
3287
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003288os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003289
3290os.path -- fix semantics of os.path.commonprefix
3291
3292smtplib -- support for sending very long messages
3293
3294socket -- new function getfqdn()
3295
3296readline -- new functions to read, write and truncate history files.
3297The readline section of the library reference manual contains an
3298example.
3299
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003300select -- add interface to poll system call
3301
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003302shutil -- new copyfileobj function
3303
3304SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3305HTTP server.
3306
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003307Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003308
3309urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003310e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003311
3312whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003313
3314
3315Obsolete Modules
3316----------------
3317
3318None. However note that 1.6 made a whole slew of modules obsolete:
3319stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3320poly, zmod, strop, util, whatsound.
3321
3322
3323Changed, New, Obsolete Tools
3324----------------------------
3325
Tim Peters8b092332000-09-05 20:15:25 +00003326None.
Guido van Rossume905e952000-09-05 12:42:46 +00003327
3328
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003329C-level Changes
3330---------------
3331
3332Several cleanup jobs were carried out throughout the source code.
3333
3334All C code was converted to ANSI C; we got rid of all uses of the
3335Py_PROTO() macro, which makes the header files a lot more readable.
3336
3337Most of the portability hacks were moved to a new header file,
3338pyport.h; several other new header files were added and some old
3339header files were removed, in an attempt to create a more rational set
3340of header files. (Few of these ever need to be included explicitly;
3341they are all included by Python.h.)
3342
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003343Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003344and Win64, especially for the new Intel Itanium processor. Mick also
3345added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003346
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003347The C APIs to return an object's size have been update to consistently
3348use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3349previous versions, the abstract interfaces used PyXXX_Length and the
3350concrete interfaces used PyXXX_Size. The old names,
3351e.g. PyObject_Length, are still available for backwards compatibility
3352at the API level, but are deprecated.
3353
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003354The PyOS_CheckStack function has been implemented on Windows by
3355Fredrik Lundh. It prevents Python from failing with a stack overflow
3356on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003357
3358The GC changes resulted in creation of two new slots on object,
3359tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003360the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003361
3362The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003363C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003364
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003365PyErr_Format has been updated to automatically calculate the size of
3366the buffer needed to hold the formatted result string. This change
3367prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003368
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003369New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003370
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003371PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3372that are the same as their non-Ex counterparts except they take an
3373extra flag argument that tells them to close the file when done.
3374
3375XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003376
Tim Peters8b092332000-09-05 20:15:25 +00003377
3378Windows Changes
3379---------------
3380
3381New popen2/popen3/peopen4 in os module (see Changed Modules above).
3382
3383os.popen is much more usable on Windows 95 and 98. See Microsoft
3384Knowledge Base article Q150956. The Win9x workaround described there
3385is implemented by the new w9xpopen.exe helper in the root of your
3386Python installation. Note that Python uses this internally; it is not
3387a standalone program.
3388
3389Administrator privileges are no longer required to install Python
3390on Windows NT or Windows 2000. If you have administrator privileges,
3391Python's registry info will be written under HKEY_LOCAL_MACHINE.
3392Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003393under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003394uses of Python, but will prevent some advanced uses from working
3395(for example, running a Python script as an NT service, or possibly
3396from CGI).
3397
3398[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3399installer; instead, it installs the needed Tcl/Tk files directly in the
3400Python directory. If you already have a Tcl/Tk installation, this
3401wastes some disk space (about 4 Megs) but avoids problems with
3402conflicting Tcl/Tk installations, and makes it much easier for Python
3403to ensure that Tcl/Tk can find all its files.
3404
3405[This was new in 1.6] The Windows installer now installs by default in
3406\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3407
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003408
3409Updates to the changes between 1.5.2 and 1.6
3410--------------------------------------------
3411
3412The 1.6 NEWS file can't be changed after the release is done, so here
3413is some late-breaking news:
3414
3415New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3416and changes to getlocale() and setlocale().
3417
3418The new module is now enabled per default.
3419
3420It is not true that the encodings codecs cannot be used for normal
3421strings: the string.encode() (which is also present on 8-bit strings
3422!) allows using them for 8-bit strings too, e.g. to convert files from
3423cp1252 (Windows) to latin-1 or vice-versa.
3424
3425Japanese codecs are available from Tamito KAJIYAMA:
3426http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3427
3428
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003429======================================================================