blob: 3d55574561eaa998f6435e9d6f65e6759e0eda1d [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
7Core and builtins
8
Guido van Rossum7dab2422002-04-26 19:40:56 +00009- New builtin function enumerate(x), from PEP 279. Example:
10 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
11 The argument can be an arbitrary iterable object.
12
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000013- The assert statement no longer tests __debug__ at runtime. This means
14 that assert statements cannot be disabled by assigning a false value
15 to __debug__.
16
Walter Dörwald068325e2002-04-15 13:36:47 +000017- A method zfill() was added to str and unicode, that fills a numeric
18 string to the left with zeros. For example,
19 "+123".zfill(6) -> "+00123".
20
Guido van Rossum862fe3c2002-04-15 12:36:47 +000021- Complex numbers supported divmod() and the // and % operators, but
22 these make no sense. Since this was documented, they're being
23 deprecated now.
24
Guido van Rossum26dd8302002-04-26 20:11:29 +000025- String and unicode methods lstrip(), rstrip() and strip() now take
26 an optional argument that specifies the characters to strip. For
27 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000028
Guido van Rossumc69343b2002-04-12 19:22:48 +000029- Added a new dict method pop(key). This removes and returns the
30 value corresponding to key. [SF patch #539949]
31
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000032- Changed new-style class instantiation so that when C's __new__
33 method returns something that's not a C instance, its __init__ is
34 not called. [SF bug #537450]
35
Guido van Rossum181e41a2002-04-06 00:23:25 +000036- Fixed super() to work correctly with class methods. [SF bug #535444]
37
Guido van Rossum47834462002-04-04 15:21:33 +000038- A new built-in type, bool, has been added, as well as built-in
39 names for its two values, True and False. Comparisons and sundry
40 other operations that return a truth value have been changed to
41 return a bool instead. Read PEP 285 for an explanantion of why this
42 is backward compatible.
43
Guido van Rossum95b62a62002-03-29 01:07:24 +000044- Fixed two bugs reported as SF #535905: under certain conditions,
45 deallocating a deeply nested structure could cause a segfault in the
46 garbage collector, due to interaction with the "trashcan" code;
47 access to the current frame during destruction of a local variable
48 could access a pointer to freed memory.
49
Neil Schemenauer9d50d132002-03-22 17:06:59 +000050- The optional object allocator has been enabled by default.
51
Guido van Rossum8c842552002-03-14 23:05:54 +000052- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000058- PyErr_Display will provide file and line information for all exceptions
59 that have an attribute print_file_and_line, not just SyntaxErrors.
60
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000061- The UTF-8 codec will now encode and decode Unicode surrogates
62 correctly and without raising exceptions for unpaired ones.
63
Neal Norwitz649b7592002-01-01 19:07:13 +000064- file.xreadlines() now raises a ValueError if the file is closed:
65 Previously, an xreadlines object was returned which would raise
66 a ValueError when the xreadlines.next() method was called.
67
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000068- posix.killpg has been added where available.
69
Neal Norwitz0c766a02002-03-27 13:03:09 +000070- sys.exit() inadvertantly allowed more than one argument.
71 An exception will now be raised if more than one argument is used.
72
Tim Petersaf8446f2001-12-21 21:36:50 +000073Extension modules
74
Tim Peters81b92512002-04-29 01:37:32 +000075- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +000076 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +000077 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +000078
Martin v. Löwis06a83e92002-04-14 10:19:44 +000079- posix.mknod was added.
80
Martin v. Löwis2e64c342002-03-27 18:49:02 +000081- The locale module now exposes the C library's gettext interface.
82
Tim Petersfbf74f22002-03-14 19:06:01 +000083- A security hole ("double free") was found in zlib-1.1.3, a popular
84 third party compression library used by some Python modules. The
85 hole was quickly plugged in zlib-1.1.4, and the Windows build of
86 Python now ships with zlib-1.1.4.
87
Martin v. Löwis688357e2002-04-08 21:28:20 +000088- pwd, grp, and resource return enhanced tuples now, with symbolic
89 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000090
Martin v. Löwis99866332002-03-01 10:27:01 +000091- array.array is now a type object. A new format character
92 'u' indicates Py_UNICODE arrays. For those, .tounicode and
93 .fromunicode methods are available. Arrays now support __iadd__
94 and __imul__.
95
Neal Norwitze790eae2002-01-01 21:14:12 +000096- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000097 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
98 is called.
99
Tim Petersaf8446f2001-12-21 21:36:50 +0000100Library
101
Fred Drake7f781c92002-05-01 20:33:53 +0000102- The pickle.Pickler class grew a clear_memo() method to mimic that
103 provided by cPickle.Pickler.
104
Tim Peters81b92512002-04-29 01:37:32 +0000105- difflib's SequenceMatcher class now does a dynamic analysis of
106 which elements are so frequent as to constitute noise. For
107 comparing files as sequences of lines, this generally works better
108 than the IS_LINE_JUNK function, and function ndiff's linejunk
109 argument defaults to None now as a result. A happy benefit is
110 that SequenceMatcher may run much faster now when applied
111 to large files with many duplicate lines (for example, C program
112 text with lots of repeated "}" and "return NULL;" lines).
113
Guido van Rossum256705b2002-04-23 13:29:43 +0000114- New Text.dump() method in Tkinter module.
115
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000116- New distutils commands for building packagers were added to
117 support pkgtool on Solaris and swinstall on HP-UX.
118
119- distutils now has a new abstract binary packager base class
120 command/bdist_packager, which simplifies writing packagers.
121 This will hopefully provide the missing bits to encourage
122 people to submit more packagers, e.g. for Debian, FreeBSD
123 and other systems.
124
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000125- The UTF-16, -LE and -BE now raise a NotImplementedError
126 for all calls to .readline(). Previously, they used to just
127 produce garbage or fail with an encoding error -- UTF-16 is
128 a 2-byte encoding and the C lib's line reading APIs don't
129 work well with these.
130
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000131- compileall now supports quiet operation.
132
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000133- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
134 connections.
135
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000136- socket module: the SSL support was broken out of the main
137 _socket module C helper and placed into a new _ssl helper
138 which now gets imported by socket.py if available and working.
139
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000140- encodings package: added aliases for all supported IANA character
141 sets
142
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000143- ftplib: to safeguard the user's privacy, anonymous login will use
144 "anonymous@" as default password, rather than the real user and host
145 name.
146
Fred Drake36736122002-01-10 13:50:31 +0000147- webbrowser: tightened up the command passed to os.system() so that
148 arbitrary shell code can't be executed because a bogus URL was
149 passed in.
150
Tim Peters11bd9942002-02-01 00:52:29 +0000151- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000152 gettext.find an optional all argument. Translations will now fallback
153 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000154
Martin v. Löwis9668b932002-01-12 11:27:42 +0000155- distutils bdist commands now offer a --skip-build option.
156
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000157- warnings.warn now accepts a Warning instance as first argument.
158
Fred Drakefed7e852002-04-04 19:36:15 +0000159- The xml.sax.expatreader.ExpatParser class will no longer create
160 circular references by using itself as the locator that gets passed
161 to the content handler implementation. [SF bug #535474]
162
Tim Petersaf8446f2001-12-21 21:36:50 +0000163Tools/Demos
164
Marc-André Lemburg46260092002-04-04 16:17:11 +0000165- freeze.py now produces binaries which can import shared modules,
166 unlike before when this failed due to missing symbol exports in
167 the generated binary.
168
Tim Petersaf8446f2001-12-21 21:36:50 +0000169Build
170
Tim Peters639295f2002-04-21 07:30:30 +0000171- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
172 say how or when to configure it, or how to turn it off.
173
Martin v. Löwis1142de32002-03-29 16:28:31 +0000174- On Unix, a shared libpython2.3.so can be created with --enable-shared.
175
Tim Peters8deda702002-03-30 10:06:07 +0000176- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
177 preprocessor symbols were eliminated. The internal decisions they
178 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000179
Tim Petersaf8446f2001-12-21 21:36:50 +0000180C API
181
Guido van Rossum517c7d42002-04-26 02:49:14 +0000182- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
183 coercion if both arguments have the same type but this type has the
184 CHECKTYPES flag set. This is to better support proxies.
185
Neil Schemenauer9344b142002-04-12 23:00:08 +0000186- The type of tp_free has been changed from "void (*)(PyObject *)" to
187 "void (*)(void *)".
188
189- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
190
Guido van Rossum0986d822002-04-08 01:38:42 +0000191- A type can now inherit its metatype from its base type. Previously,
192 when PyType_Ready() was called, if ob_type was found to be NULL, it
193 was always set to &PyType_Type; now it is set to base->ob_type,
194 where base is tp_base, defaulting to &PyObject_Type.
195
196- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
197
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000198- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
199 functions will be allocated using pymalloc if it is enabled. These
200 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
201 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
202 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
203 PyCore_* family of APIs have been removed.
204
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000205- The "u#" parser marker will now pass through Unicode object as-is
206 without going through the buffer API.
207
Martin v. Löwis7198a522002-01-01 19:59:11 +0000208- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
209
Tim Peters10a3bb52001-12-25 19:07:38 +0000210- An old #define of ANY as void has been removed from pyport.h. This
211 hasn't been used since Python's pre-ANSI days, and the #define has
212 been marked as obsolete since then. SF bug 495548 says it created
213 conflicts with other packages, so keeping it around wasn't harmless.
214
Tim Petersaf8446f2001-12-21 21:36:50 +0000215- Because Python's magic number scheme broke on January 1st, we decided
216 to stop Python development. Thanks for all the fish!
217
Tim Petersfb05db22002-03-11 00:24:00 +0000218- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000219 scheme to a new one. See Python/import.c for details.
220
Tim Petersaf8446f2001-12-21 21:36:50 +0000221New platforms
222
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000223- GNU/Hurd is now supported.
224
Tim Petersaf8446f2001-12-21 21:36:50 +0000225Tests
226
227Windows
228
Tim Peters08e72952002-04-16 20:48:01 +0000229- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
230 of that has been fixed in the installer (disabled Wise's "delete in-
231 use files" uninstall option).
232
Guido van Rossum181e41a2002-04-06 00:23:25 +0000233- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
234
Tim Peters33187922002-04-04 20:02:04 +0000235- The installer now installs Start menu shortcuts under (the local
236 equivalent of) "All Users" when doing an Admin install.
237
Tim Petersfb05db22002-03-11 00:24:00 +0000238- file.truncate([newsize]) now works on Windows for all newsize values.
239 It used to fail if newsize didn't fit in 32 bits, reflecting a
240 limitation of MS _chsize (which is no longer used).
241
Tim Petersab034fa2002-02-01 11:27:43 +0000242- os.waitpid() is now implemented for Windows, and can be used to block
243 until a specified process exits. This is similar to, but not exactly
244 the same as, os.waitpid() on POSIX systems. If you're waiting for
245 a specific process whose pid was obtained from one of the spawn()
246 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000247 See the docs for details. The docs were changed to clarify that
248 spawn functions return, and waitpid requires, a process handle on
249 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000250
Tim Peters11bd9942002-02-01 00:52:29 +0000251- New tempfile.TemporaryFile implementation for Windows: this doesn't
252 need a TemproraryFileWrapper wrapper anymore, and should be immune
253 to a nasty problem: before 2.3, if you got a temp file on Windows, it
254 got wrapped in an object whose close() method first closed the
255 underlying file, then deleted the file. This usually worked fine.
256 However, the spawn family of functions on Windows create (at a low C
257 level) the same set of open files in the spawned process Q as were
258 open in the spawning process P. If a temp file f was among them, then
259 doing f.close() in P first closed P's C-level file handle on f, but Q's
260 C-level file handle on f remained open, so the attempt in P to delete f
261 blew up with a "Permission denied" error (Windows doesn't allow
262 deleting open files). This was surprising, subtle, and difficult to
263 work around.
264
265- The os module now exports all the symbolic constants usable with the
266 low-level os.open() on Windows: the new constants in 2.3 are
267 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
268 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
269 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
270 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
271 (so specify both if you want both; note that neither is useful unless
272 specified with O_CREAT too).
273
Tim Petersaf8446f2001-12-21 21:36:50 +0000274Mac
275
276
Tim Peters909c0912001-12-14 23:16:18 +0000277What's New in Python 2.2 final?
278Release date: 21-Dec-2001
279===============================
280
281Type/class unification and new-style classes
282
Barry Warsaw52acb492001-12-21 20:04:22 +0000283- pickle.py, cPickle: allow pickling instances of new-style classes
284 with a custom metaclass.
285
Tim Peters909c0912001-12-14 23:16:18 +0000286Core and builtins
287
Barry Warsaw52acb492001-12-21 20:04:22 +0000288- weakref proxy object: when comparing, unwrap both arguments if both
289 are proxies.
290
Tim Peters909c0912001-12-14 23:16:18 +0000291Extension modules
292
Barry Warsaw52acb492001-12-21 20:04:22 +0000293- binascii.b2a_base64(): fix a potential buffer overrun when encoding
294 very short strings.
295
296- cPickle: the obscure "fast" mode was suspected of causing stack
297 overflows on the Mac. Hopefully fixed this by setting the recursion
298 limit much smaller. If the limit is too low (it only affects
299 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
300 when compiling cPickle.c (or in pyconfig.h).
301
Tim Peters909c0912001-12-14 23:16:18 +0000302Library
303
Barry Warsaw52acb492001-12-21 20:04:22 +0000304- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
305 close or delete time).
306
307- rfc822.py: fixed a bug where the address '<>' was converted to None
308 instead of an empty string (also fixes the email.Utils module).
309
310- xmlrpclib.py: version 1.0.0; uses precision for doubles.
311
312- test suite: the pickle and cPickle tests were not executing any code
313 when run from the standard regresssion test.
314
Tim Peters909c0912001-12-14 23:16:18 +0000315Tools/Demos
316
317Build
318
319C API
320
321New platforms
322
323Tests
324
325Windows
326
Barry Warsaw52acb492001-12-21 20:04:22 +0000327- distutils package: fixed broken Windows installers (bdist_wininst).
328
329- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
330 instances are deleted at process exit time.
331
332- socket.py: prevent mysterious warnings when socket instances are
333 deleted at process exit time.
334
335- posixmodule.c: fix a Windows crash with stat() of a filename ending
336 in backslash.
337
Tim Peters909c0912001-12-14 23:16:18 +0000338Mac
339
Barry Warsaw52acb492001-12-21 20:04:22 +0000340- The Carbon toolbox modules have been upgraded to Universal Headers
341 3.4, and experimental CoreGraphics and CarbonEvents modules have
342 been added. All only for framework-enabled MacOSX.
343
Tim Peters909c0912001-12-14 23:16:18 +0000344
Tim Peters6272dfd2001-12-13 19:34:00 +0000345What's New in Python 2.2c1?
346Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000347===========================
348
349Type/class unification and new-style classes
350
Barry Warsaw06557452001-12-14 20:47:12 +0000351- Guido's tutorial introduction to the new type/class features has
352 been extensively updated. See
353
354 http://www.python.org/2.2/descrintro.html
355
356 That remains the primary documentation in this area.
357
Guido van Rossum33bab012001-12-05 22:45:48 +0000358- Fixed a leak: instance variables declared with __slots__ were never
359 deleted!
360
Guido van Rossum4b800852001-12-03 00:54:52 +0000361- The "delete attribute" method of descriptor objects is called
362 __delete__, not __del__. In previous releases, it was mistakenly
363 called __del__, which created an unfortunate overloading condition
364 with finalizers. (The "get attribute" and "set attribute" methods
365 are still called __get__ and __set__, respectively.)
366
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000367- Some subtle issues with the super built-in were fixed:
368
369 (a) When super itself is subclassed, its __get__ method would still
370 return an instance of the base class (i.e., of super).
371
372 (b) super(C, C()).__class__ would return C rather than super. This
373 is confusing. To fix this, I decided to change the semantics of
374 super so that it only applies to code attributes, not to data
375 attributes. After all, overriding data attributes is not
376 supported anyway.
377
378 (c) The __get__ method didn't check whether the argument was an
379 instance of the type used in creation of the super instance.
380
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000381- Previously, hash() of an instance of a subclass of a mutable type
382 (list or dictionary) would return some value, rather than raising
383 TypeError. This has been fixed. Also, directly calling
384 dict.__hash__ and list.__hash__ now raises the same TypeError
385 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000386
Guido van Rossumd331cb52001-12-05 19:46:42 +0000387- New-style objects now support deleting their __dict__. This is for
388 all intents and purposes equivalent to assigning a brand new empty
389 dictionary, but saves space if the object is not used further.
390
Tim Petersb3c9af12001-11-17 00:21:57 +0000391Core and builtins
392
Tim Peters3caca232001-12-06 06:23:26 +0000393- -Qnew now works as documented in PEP 238: when -Qnew is passed on
394 the command line, all occurrences of "/" use true division instead
395 of classic division. See the PEP for details. Note that "all"
396 means all instances in library and 3rd-party modules, as well as in
397 your own code. As the PEP says, -Qnew is intended for use only in
398 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000399 Note that test_coercion.py in the standard Python test suite fails
400 under -Qnew; this is expected, and won't be repaired until true
401 division becomes the default (in the meantime, test_coercion is
402 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000403
Fred Drake6c01e252001-12-14 17:08:12 +0000404- complex() now only allows the first argument to be a string
405 argument, and raises TypeError if either the second arg is a string
406 or if the second arg is specified when the first is a string.
407
Tim Petersb3c9af12001-11-17 00:21:57 +0000408Extension modules
409
Martin v. Löwis560da622001-11-24 09:24:51 +0000410- gc.get_referents was renamed to gc.get_referrers.
411
Tim Petersb3c9af12001-11-17 00:21:57 +0000412Library
413
Tim Peters25059d32001-12-07 20:35:43 +0000414- Functions in the os.spawn() family now release the global interpreter
415 lock around calling the platform spawn. They should always have done
416 this, but did not before 2.2c1. Multithreaded programs calling
417 an os.spawn function with P_WAIT will no longer block all Python threads
418 until the spawned program completes. It's possible that some programs
419 relies on blocking, although more likely by accident than by design.
420
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000421- webbrowser defaults to netscape.exe on OS/2 now.
422
Martin v. Löwis652e1912001-11-25 14:50:56 +0000423- Tix.ResizeHandle exposes detach_widget, hide, and show.
424
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000425- The charset alias windows_1252 has been added.
426
Barry Warsaw06557452001-12-14 20:47:12 +0000427- types.StringTypes is a tuple containing the defined string types;
428 usually this will be (str, unicode), but if Python was compiled
429 without Unicode support it will be just (str,).
430
431- The pulldom and minidom modules were synchronized to PyXML.
432
Tim Petersb3c9af12001-11-17 00:21:57 +0000433Tools/Demos
434
Barry Warsaw06557452001-12-14 20:47:12 +0000435- A new script called Tools/scripts/google.py was added, which fires
436 off a search on Google.
437
Tim Petersb3c9af12001-11-17 00:21:57 +0000438Build
439
Barry Warsaw06557452001-12-14 20:47:12 +0000440- Note that release builds of Python should arrange to define the
441 preprocessor symbol NDEBUG on the command line (or equivalent).
442 In the 2.2 pre-release series we tried to define this by magic in
443 Python.h instead, but it proved to cause problems for extension
444 authors. The Unix, Windows and Mac builds now all define NDEBUG in
445 release builds via cmdline (or equivalent) instead. Ports to
446 other platforms should do likewise.
447
Jack Jansen1999ef42001-12-06 21:47:20 +0000448- It is no longer necessary to use --with-suffix when building on a
449 case-insensitive file system (such as Mac OS X HFS+). In the build
450 directory an extension is used, but not in the installed python.
451
Tim Petersb3c9af12001-11-17 00:21:57 +0000452C API
453
Tim Petersf582b822001-12-11 18:51:08 +0000454- New function PyDict_MergeFromSeq2() exposes the builtin dict
455 constructor's logic for updating a dictionary from an iterable object
456 producing key-value pairs.
457
Tim Peterscffed4b2001-11-29 03:26:37 +0000458- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000459 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000460 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
461 dump core in some bad cases. This has been repaired. As a result,
462 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
463 previously went unchallenged.
464
Tim Petersb3c9af12001-11-17 00:21:57 +0000465New platforms
466
467Tests
468
469Windows
470
471Mac
472
Jack Jansenffa260f2001-12-06 21:14:00 +0000473- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
474 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000475
Barry Warsaw06557452001-12-14 20:47:12 +0000476- Changed logic for finding python home in Mac OS X framework Pythons.
477 Now sys.executable points to the executable again, in stead of to
478 the shared library. The latter is used only for locating the python
479 home.
480
481
Tim Peters84362bc2001-10-19 17:55:30 +0000482What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000483Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000484===========================
485
486Type/class unification and new-style classes
487
Guido van Rossum3d27df02001-11-15 20:27:54 +0000488- Multiple inheritance mixing new-style and classic classes in the
489 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000490
491 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000492 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000493
494 The MRO (method resolution order) for each base class is respected
495 according to its kind, but the MRO for the derived class is computed
496 using new-style MRO rules if any base clase is a new-style class.
497 This needs to be documented.
498
Tim Petersa427a2b2001-10-29 22:25:45 +0000499- The new builtin dictionary() constructor, and dictionary type, have
500 been renamed to dict. This reflects a decade of common usage.
501
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000502- dict() now accepts an iterable object producing 2-sequences. For
503 example, dict(d.items()) == d for any dictionary d. The argument,
504 and the elements of the argument, can be any iterable objects.
505
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000506- New-style classes can now have a __del__ method, which is called
507 when the instance is deleted (just like for classic classes).
508
Guido van Rossum12d955c2001-10-26 14:56:06 +0000509- Assignment to object.__dict__ is now possible, for objects that are
510 instances of new-style classes that have a __dict__ (unless the base
511 class forbids it).
512
Guido van Rossumc8e56452001-10-22 00:43:43 +0000513- Methods of built-in types now properly check for keyword arguments
514 (formerly these were silently ignored). The only built-in methods
515 that take keyword arguments are __call__, __init__ and __new__.
516
Guido van Rossum86443212001-10-27 22:28:54 +0000517- The socket function has been converted to a type; see below.
518
Tim Peters84362bc2001-10-19 17:55:30 +0000519Core and builtins
520
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000521- Assignment to __debug__ raises SyntaxError at compile-time. This
522 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000523 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000524
Guido van Rossum12d955c2001-10-26 14:56:06 +0000525- Clarified the error messages for unsupported operands to an operator
526 (like 1 + '').
527
Tim Peters84362bc2001-10-19 17:55:30 +0000528Extension modules
529
Tim Peters5ebfd362001-11-13 23:11:19 +0000530- mmap has a new keyword argument, "access", allowing a uniform way for
531 both Windows and Unix users to create read-only, write-through and
532 copy-on-write memory mappings. This was previously possible only on
533 Unix. A new keyword argument was required to support this in a
534 uniform way because the mmap() signuatures had diverged across
535 platforms. Thanks to Jay T Miller for repairing this!
536
Tim Peters169ded02001-11-03 19:57:21 +0000537- By default, the gc.garbage list now contains only those instances in
538 unreachable cycles that have __del__ methods; in 2.1 it contained all
539 instances in unreachable cycles. "Instances" here has been generalized
540 to include instances of both new-style and old-style classes.
541
Guido van Rossum12d955c2001-10-26 14:56:06 +0000542- The socket module defines a new method for socket objects,
543 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000544 send() until all data has been sent. Also, the socket function has
545 been converted to a subclassable type, like list and tuple (etc.)
546 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000547
548- Various bugfixes to the curses module. There is now a test suite
549 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000550
Guido van Rossum692adf12001-10-30 03:03:03 +0000551- binascii.b2a_base64 no longer places an arbitrary restriction of 57
552 bytes on its input.
553
Tim Peters84362bc2001-10-19 17:55:30 +0000554Library
555
Tim Peters5ebfd362001-11-13 23:11:19 +0000556- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000557 convenience function.
558
Tim Peters75335872001-11-03 19:35:43 +0000559- Symbolic group names in regular expressions must be unique. For
560 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
561 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000562 Python 2.2 detects this error at regexp compilation time;
563 previously, the error went undetected, and results were
564 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
565 pattern.subn() methods have been rewritten in C. Also, an
566 experimental function/method finditer() has been added, which works
567 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000568
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000569- Tix exposes more commands through the classes DirSelectBox,
570 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
571 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
572 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
573
Tim Peters98791af2001-10-23 01:59:54 +0000574- Traceback objects are now scanned by cyclic garbage collection, so
575 cycles created by casual use of sys.exc_info() no longer cause
576 permanent memory leaks (provided garbage collection is enabled).
577
Guido van Rossum49192142001-10-24 20:51:44 +0000578- os.extsep -- a new variable needed by the RISCOS support. It is the
579 separator used by extensions, and is '.' on all platforms except
580 RISCOS, where it is '/'. There is no need to use this variable
581 unless you have a masochistic desire to port your code to RISCOS.
582
Barry Warsaw012852b2001-11-16 16:17:27 +0000583- mimetypes.py has optional support for non-standard, but commonly
584 found types. guess_type() and guess_extension() now accept an
585 optional `strict' flag, defaulting to true, which controls whether
586 recognize non-standard types or not. A few non-standard types we
587 know about have been added. Also, when run as a script, there are
588 new -l and -e options.
589
590- statcache is now deprecated.
591
592- email.Utils.formatdate() now produces the preferred RFC 2822 style
593 dates with numeric timezones (it used to produce obsolete dates
594 hard coded to "GMT" timezone). An optional `localtime' flag is
595 added to produce dates in the local timezone, with daylight savings
596 time properly taken into account.
597
598- In pickle and cPickle, instead of masking errors in load() by
599 transforming them into SystemError, we let the original exception
600 propagate out. Also, implement support for __safe_for_unpickling__
601 in pickle, as it already was supported in cPickle.
602
Tim Peters84362bc2001-10-19 17:55:30 +0000603Tools/Demos
604
605Build
606
Barry Warsaw012852b2001-11-16 16:17:27 +0000607- The dbm module is built using libdb1 if available. The bsddb module
608 is built with libdb3 if available.
609
610- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
611
Tim Peters84362bc2001-10-19 17:55:30 +0000612C API
613
Tim Peters1fc240e2001-10-26 05:06:50 +0000614- New function PySequence_Fast_GET_SIZE() returns the size of a non-
615 NULL result from PySequence_Fast(), more quickly than calling
616 PySequence_Size().
617
Barry Warsaw012852b2001-11-16 16:17:27 +0000618- New argument unpacking function PyArg_UnpackTuple() added.
619
620- New functions PyObject_CallFunctionObjArgs() and
621 PyObject_CallMethodObjArgs() have been added to make it more
622 convenient and efficient to call functions and methods from C.
623
624- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
625 possible that this will propagate errors it didn't before.
626
627- New function PyObject_CheckReadBuffer(), which returns true if its
628 argument supports the single-segment readable buffer interface.
629
Tim Peters84362bc2001-10-19 17:55:30 +0000630New platforms
631
Guido van Rossum86443212001-10-27 22:28:54 +0000632- We've finally confirmed that this release builds on HP-UX 11.00,
633 *with* threads, and passes the test suite.
634
Tim Peters7a33d8b2001-11-05 02:51:07 +0000635- Thanks to a series of patches from Michael Muller, Python may build
636 again under OS/2 Visual Age C++.
637
Guido van Rossum49192142001-10-24 20:51:44 +0000638- Updated RISCOS port by Dietmar Schwertberger.
639
Tim Peters84362bc2001-10-19 17:55:30 +0000640Tests
641
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000642- Added a test script for the curses module. It isn't run automatically;
643 regrtest.py must be run with '-u curses' to enable it.
644
Tim Peters84362bc2001-10-19 17:55:30 +0000645Windows
646
Barry Warsaw012852b2001-11-16 16:17:27 +0000647Mac
648
649- PythonScript has been moved to unsupported and is slated to be
650 removed completely in the next release.
651
652- It should now be possible to build applets that work on both OS9 and
653 OSX.
654
655- The core is now linked with CoreServices not Carbon; as a side
656 result, default 8bit encoding on OSX is now ASCII.
657
658- Python should now build on OSX 10.1.1
659
Tim Peters84362bc2001-10-19 17:55:30 +0000660
Tim Petersabf925f2001-09-28 21:53:42 +0000661What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000662Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000663===========================
664
665Type/class unification and new-style classes
666
Guido van Rossum687ae002001-10-15 22:03:32 +0000667- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000668 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000669 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000670 remains: the __dict__ of a new-style class is a read-only proxy; you
671 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000672 __defined__ attribute of new-style types no longer exists, for lack
673 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000674 future a __cache__ may be resurrected with a similar function, if I
675 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000676
Tim Peters1c9ca872001-10-04 06:43:12 +0000677- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
678 always returned None, even when there was a class docstring).
679
680- doctest now finds and runs docstrings attached to new-style classes,
681 class methods, static methods, and properties.
682
Guido van Rossum9074ef62001-10-16 21:34:49 +0000683Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000684
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000685- A very subtle syntactical pitfall in list comprehensions was fixed.
686 For example: [a+b for a in 'abc', for b in 'def']. The comma in
687 this example is a mistake. Previously, this would silently let 'a'
688 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
689 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
690 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
691 Note that [a for a in <singleton>] is a convoluted way to say
692 [<singleton>] anyway, so it's not like any expressiveness is lost.
693
Guido van Rossum9074ef62001-10-16 21:34:49 +0000694- getattr(obj, name, default) now only catches AttributeError, as
695 documented, rather than returning the default value for all
696 exceptions (which could mask bugs in a __getattr__ hook, for
697 example).
698
Fred Drakecb7a6b52001-10-22 18:41:51 +0000699- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000700 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000701 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000702 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000703
Guido van Rossum1c486092001-10-19 02:05:35 +0000704- unicode(obj) now behaves more like str(obj), accepting arbitrary
705 objects, and calling a __unicode__ method if it exists.
706 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000707 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000708
Barry Warsawf6fb1712001-10-19 05:35:40 +0000709- isinstance() now allows any object as the first argument and a
710 class, a type or something with a __bases__ tuple attribute for the
711 second argument. The second argument may also be a tuple of a
712 class, type, or something with __bases__, in which case isinstance()
713 will return true if the first argument is an instance of any of the
714 things contained in the second argument tuple. E.g.
715
716 isinstance(x, (A, B))
717
718 returns true if x is an instance of A or B.
719
Guido van Rossum9074ef62001-10-16 21:34:49 +0000720Extension modules
721
722- thread.start_new_thread() now returns the thread ID (previously None).
723
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000724- binascii has now two quopri support functions, a2b_qp and b2a_qp.
725
Guido van Rossumc524d952001-10-19 01:31:59 +0000726- readline now supports setting the startup_hook and the
727 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000728
Guido van Rossumc524d952001-10-19 01:31:59 +0000729- os and posix supports chroot(), setgroups() and unsetenv() where
730 available. The stat(), fstat(), statvfs() and fstatvfs() functions
731 now return "pseudo-sequences" -- the various fields can now be
732 accessed as attributes (e.g. os.stat("/").st_mtime) but for
733 backwards compatibility they also behave as a fixed-length sequence.
734 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000735 attributes.
736
737- time: localtime(), gmtime() and strptime() now return a
738 pseudo-sequence similar to the os.stat() return value, with
739 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000740
Guido van Rossum9074ef62001-10-16 21:34:49 +0000741- Decompression objects in the zlib module now accept an optional
742 second parameter to decompress() that specifies the maximum amount
743 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000744
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000745- optional SSL support in the socket module now exports OpenSSL
746 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
747 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000748 automatically seed its PRNG. Also, the keyfile and certfile
749 arguments to socket.ssl() are now optional.
750
751- posixmodule (and by extension, the os module on POSIX platforms) now
752 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000753
Guido van Rossum9074ef62001-10-16 21:34:49 +0000754Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000755
Tim Peters7402f792001-10-02 03:53:41 +0000756- doctest now excludes functions and classes not defined by the module
757 being tested, thanks to Tim Hochberg.
758
Fred Drakecb7a6b52001-10-22 18:41:51 +0000759- HotShot, a new profiler implemented using a C-based callback, has
760 been added. This substantially reduces the overhead of profiling,
761 but it is still quite preliminary. Support modules and
762 documentation will be added in upcoming releases (before 2.2 final).
763
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000764- profile now produces correct output in situations where an exception
765 raised in Python is cleared by C code (e.g. hasattr()). This used
766 to cause wrong output, including spurious claims of recursive
767 functions and attribution of time spent to the wrong function.
768
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000769 The code and documentation for the derived OldProfile and HotProfile
770 profiling classes was removed. The code hasn't worked for years (if
771 you tried to use them, they raised exceptions). OldProfile
772 intended to reproduce the behavior of the profiler Python used more
773 than 7 years ago, and isn't interesting anymore. HotProfile intended
774 to provide a faster profiler (but producing less information), and
775 that's a worthy goal we intend to meet via a different approach (but
776 without losing information).
777
Tim Peterscce092d2001-10-09 05:31:56 +0000778- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000779 a much better system-specific calibration constant. The constant can
780 now be specified in an instance constructor, or as a Profile class or
781 instance variable, instead of by editing profile.py's source code.
782 Calibration must still be done manually (see the docs for the profile
783 module).
784
785 Note that Profile.calibrate() must be overriden by subclasses.
786 Improving the accuracy required exploiting detailed knowledge of
787 profiler internals; the earlier method abstracted away the details
788 and measured a simplified model instead, but consequently computed
789 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000790
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000791- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000792 which indicates whether output is intended for the header 'Q'
793 encoding.
794
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000795- The SocketServer.ThreadingMixIn class now closes the request after
796 finish_request() returns. (Not when it errors out though.)
797
Barry Warsawf6fb1712001-10-19 05:35:40 +0000798- The nntplib module's NNTP.body() method has grown a `file' argument
799 to allow saving the message body to a file.
800
801- The email package has added a class email.Parser.HeaderParser which
802 only parses headers and does not recurse into the message's body.
803 Also, the module/class MIMEAudio has been added for representing
804 audio data (contributed by Anthony Baxter).
805
806- ftplib should be able to handle files > 2GB.
807
808- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
809 ON, and OFF.
810
Fred Drakecb7a6b52001-10-22 18:41:51 +0000811- xml.dom.minidom NodeList objects now support the length attribute
812 and item() method as required by the DOM specifications.
813
Guido van Rossumed554f62001-10-02 23:15:37 +0000814Tools/Demos
815
816- Demo/dns was removed. It no longer serves any purpose; a package
817 derived from it is now maintained by Anthony Baxter, see
818 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000819
Barry Warsawf6fb1712001-10-19 05:35:40 +0000820- The freeze tool has been made more robust, and two new options have
821 been added: -X and -E.
822
Tim Petersabf925f2001-09-28 21:53:42 +0000823Build
824
Barry Warsawf6fb1712001-10-19 05:35:40 +0000825- configure will use CXX in LINKCC if CXX is used to build main() and
826 the system requires to link a C++ main using the C++ compiler.
827
Tim Petersabf925f2001-09-28 21:53:42 +0000828C API
829
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000830- The documentation for the tp_compare slot is updated to require that
831 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
832 not correct. This is not yet enforced but will be enforced in
833 Python 2.3; even later, we may use -2 to indicate errors and +2 for
834 "NotImplemented". Right now, -1 should be used for an error return.
835
Tim Petersd38b1c72001-09-30 05:09:37 +0000836- PyLong_AsLongLong() now accepts int (as well as long) arguments.
837 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
838 as long) arguments.
839
Guido van Rossum3c288632001-10-16 21:13:49 +0000840- PyThread_start_new_thread() now returns a long int giving the thread
841 ID, if one can be calculated; it returns -1 for error, 0 if no
842 thread ID is calculated (this is an incompatible change, but only
843 the thread module used this API). This code has only really been
844 tested on Linux and Windows; other platforms please beware (and
845 report any bugs or strange behavior).
846
Guido van Rossum1c486092001-10-19 02:05:35 +0000847- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
848 input.
849
Tim Petersabf925f2001-09-28 21:53:42 +0000850New platforms
851
852Tests
853
854Windows
855
Tim Peters04cf1d32001-10-09 22:39:40 +0000856- Installer: If you install IDLE, and don't disable file-extension
857 registration, a new "Edit with IDLE" context (right-click) menu entry
858 is created for .py and .pyw files.
859
Tim Peters1ce3cf72001-10-01 17:58:40 +0000860- The signal module now supports SIGBREAK on Windows, thanks to Steven
861 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
862 action remains to call Win32 ExitProcess(). This can be changed via
863 signal.signal(). For example:
864
865 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
866 # (SIGINT) behavior.
867 import signal
868 signal.signal(signal.SIGBREAK,
869 signal.default_int_handler)
870
871 try:
872 while 1:
873 pass
874 except KeyboardInterrupt:
875 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
876 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
877 # program without the possibility for any Python-level cleanup).
878 print "Clean exit"
879
Tim Petersabf925f2001-09-28 21:53:42 +0000880
Tim Petersb07352e2001-09-08 01:25:47 +0000881What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000882Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000883===========================
884
Guido van Rossum808eea72001-09-25 04:15:41 +0000885Type/class unification and new-style classes
886
887- pydoc and inspect are now aware of new-style classes;
888 e.g. help(list) at the interactive prompt now shows proper
889 documentation for all operations on list objects.
890
891- Applications using Jim Fulton's ExtensionClass module can now safely
892 be used with Python 2.2. In particular, Zope 2.4.1 now works with
893 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
894 examples also work again. It is hoped that Gtk and Boost also work
895 with 2.2a4 and beyond. (If you can confirm this, please write
896 webmaster@python.org; if there are still problems, please open a bug
897 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000898
Tim Peters66c1a522001-09-24 21:17:50 +0000899- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
900 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
901 in the constructed property object. fget, fset and fdel weren't
902 discoverable from Python in 2.2a3. __doc__ is new, and allows to
903 associate a docstring with a property.
904
Guido van Rossum808eea72001-09-25 04:15:41 +0000905- Comparison overloading is now more completely implemented. For
906 example, a str subclass instance can properly be compared to a str
907 instance, and it can properly overload comparison. Ditto for most
908 other built-in object types.
909
910- The repr() of new-style classes has changed; instead of <type
911 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
912 *except* for built-in types, which are still rendered as <type
913 'Foo'> (to avoid upsetting existing code that might parse or
914 otherwise rely on repr() of certain type objects).
915
916- The repr() of new-style objects is now always <Foo object at XXX>;
917 previously, it was sometimes <Foo instance at XXX>.
918
919- For new-style classes, what was previously called __getattr__ is now
920 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000921 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000922 one in classic classes is defined which is called only if regular
923 attribute access raises AttributeError; to catch *all* attribute
924 access, you can use __getattribute__ (for new-style classes). If
925 both are defined, __getattribute__ is called first, and if it raises
926 AttributeError, __getattr__ is called.
927
928- The __class__ attribute of new-style objects can be assigned to.
929 The new class must have the same C-level object layout as the old
930 class.
931
932- The builtin file type can be subclassed now. In the usual pattern,
933 "file" is the name of the builtin type, and file() is a new builtin
934 constructor, with the same signature as the builtin open() function.
935 file() is now the preferred way to open a file.
936
937- Previously, __new__ would only see sequential arguments passed to
938 the type in a constructor call; __init__ would see both sequential
939 and keyword arguments. This made no sense whatsoever any more, so
940 now both __new__ and __init__ see all arguments.
941
942- Previously, hash() applied to an instance of a subclass of str or
943 unicode always returned 0. This has been repaired.
944
945- Previously, an operation on an instance of a subclass of an
946 immutable type (int, long, float, complex, tuple, str, unicode),
947 where the subtype didn't override the operation (and so the
948 operation was handled by the builtin type), could return that
949 instance instead a value of the base type. For example, if s was of
950 a str sublass type, s[:] returned s as-is. Now it returns a str
951 with the same value as s.
952
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000953- Provisional support for pickling new-style objects has been added.
954
Guido van Rossum808eea72001-09-25 04:15:41 +0000955Core
956
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000957- file.writelines() now accepts any iterable object producing strings.
958
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000959- PyUnicode_FromEncodedObject() now works very much like
960 PyObject_Str(obj) in that it tries to use __str__/tp_str
961 on the object if the object is not a string or buffer. This
962 makes unicode() behave like str() when applied to non-string/buffer
963 objects.
964
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000965- PyFile_WriteObject now passes Unicode objects to the file's write
966 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000967 of a print statement must support Unicode objects, i.e. they must
968 at least convert them into ASCII strings.
969
Guido van Rossum624c8af2001-09-18 15:21:04 +0000970- Thread scheduling on Solaris should be improved; it is no longer
971 necessary to insert a small sleep at the start of a thread in order
972 to let other runnable threads be scheduled.
973
Tim Petersb07352e2001-09-08 01:25:47 +0000974Library
975
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000976- StringIO.StringIO instances and cStringIO.StringIO instances support
977 read character buffer compatible objects for their .write() methods.
978 These objects are converted to strings and then handled as such
979 by the instances.
980
Barry Warsaw2f600732001-09-24 04:28:10 +0000981- The "email" package has been added. This is basically a port of the
982 mimelib package <http://sf.net/projects/mimelib> with API changes
983 and some implementations updated to use iterators and generators.
984
Tim Peters8a9c2842001-09-22 21:30:22 +0000985- difflib.ndiff() and difflib.Differ.compare() are generators now. This
986 restores the ability of Tools/scripts/ndiff.py to start producing output
987 before the entire comparison is complete.
988
Barry Warsaw58b072d2001-09-22 04:44:21 +0000989- StringIO.StringIO instances and cStringIO.StringIO instances support
990 iteration just like file objects (i.e. their .readline() method is
991 called for each iteration until it returns an empty string).
992
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000993- The codecs module has grown four new helper APIs to access
994 builtin codecs: getencoder(), getdecoder(), getreader(),
995 getwriter().
996
Guido van Rossum624c8af2001-09-18 15:21:04 +0000997- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
998 simplifies writing XML RPC servers.
999
Barry Warsaw647d5e82001-09-28 17:01:02 +00001000- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001001 after interpretation of symbolic links. On non-Unix systems, this
1002 is an alias for os.path.abspath().
1003
Tim Peters16a77ad2001-09-08 04:00:12 +00001004- operator.indexOf() (PySequence_Index() in the C API) now works with any
1005 iterable object.
1006
Guido van Rossum624c8af2001-09-18 15:21:04 +00001007- smtplib now supports various authentication and security features of
1008 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001009
Guido van Rossum624c8af2001-09-18 15:21:04 +00001010- hmac: a new module implementing keyed hashing for message
1011 authentication.
1012
1013- mimetypes now recognizes more extensions and file types. At the
1014 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001015
Guido van Rossum624c8af2001-09-18 15:21:04 +00001016- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001017 Python 2.2 bytecode generation. It has also been promoted from a
1018 Tool to a standard library package. (Tools/compiler still exists as
1019 a sample driver.)
1020
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001021Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001022
Tim Petersb07352e2001-09-08 01:25:47 +00001023Build
1024
Guido van Rossum624c8af2001-09-18 15:21:04 +00001025- Large file support (LFS) is now automatic when the platform supports
1026 it; no more manual configuration tweaks are needed. On Linux, at
1027 least, it's possible to have a system whose C library supports large
1028 files but whose kernel doesn't; in this case, large file support is
1029 still enabled but doesn't do you any good unless you upgrade your
1030 kernel or share your Python executable with another system whose
1031 kernel has large file support.
1032
1033- The configure script now supplies plausible defaults in a
1034 cross-compilation environment. This doesn't mean that the supplied
1035 values are always correct, or that cross-compilation now works
1036 flawlessly -- but it's a first step (and it shuts up most of
1037 autoconf's warnings about AC_TRY_RUN).
1038
1039- The Unix build is now a bit less chatty, courtesy of the parser
1040 generator. The build is completely silent (except for errors) when
1041 using "make -s", thanks to a -q option to setup.py.
1042
Tim Petersb07352e2001-09-08 01:25:47 +00001043C API
1044
Guido van Rossum624c8af2001-09-18 15:21:04 +00001045- The "structmember" API now supports some new flag bits to deny read
1046 and/or write access to attributes in restricted execution mode.
1047
Tim Petersb07352e2001-09-08 01:25:47 +00001048New platforms
1049
Guido van Rossum624c8af2001-09-18 15:21:04 +00001050- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1051 (http://familiar.handhelds.org).
1052
Tim Petersb07352e2001-09-08 01:25:47 +00001053Tests
1054
Tim Peters8a9c2842001-09-22 21:30:22 +00001055- The "classic" standard tests, which work by comparing stdout to
1056 an expected-output file under Lib/test/output/, no longer stop at
1057 the first mismatch. Instead the test is run to completion, and a
1058 variant of ndiff-style comparison is used to report all differences.
1059 This is much easier to understand than the previous style of reporting.
1060
1061- The unittest-based standard tests now use regrtest's test_main()
1062 convention, instead of running as a side-effect of merely being
1063 imported. This allows these tests to be run in more natural and
1064 flexible ways as unittests, outside the regrtest framework.
1065
1066- regrtest.py is much better integrated with unittest and doctest now,
1067 especially in regard to reporting errors.
1068
Tim Petersb07352e2001-09-08 01:25:47 +00001069Windows
1070
Guido van Rossum624c8af2001-09-18 15:21:04 +00001071- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001072 that support it (NTFS under Windows 2000). See "What's New in
1073 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001074
Tim Petersb07352e2001-09-08 01:25:47 +00001075
Tim Petersedc99312001-08-22 21:36:50 +00001076What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001077Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001078===========================
1079
1080Core
1081
Tim Peters9fffa3e2001-09-04 05:14:19 +00001082- Conversion of long to float now raises OverflowError if the long is too
1083 big to represent as a C double.
1084
Tim Peters32f453e2001-09-03 08:35:41 +00001085- The 3-argument builtin pow() no longer allows a third non-None argument
1086 if either of the first two arguments is a float, or if both are of
1087 integer types and the second argument is negative (in which latter case
1088 the arguments are converted to float, so this is really the same
1089 restriction).
1090
Tim Peters5d2b77c2001-09-03 05:47:38 +00001091- The builtin dir() now returns more information, and sometimes much
1092 more, generally naming all attributes of an object, and all attributes
1093 reachable from the object via its class, and from its class's base
1094 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1095 an empty list. In 2.2a3,
1096
1097 >>> dir([])
1098 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1099 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1100 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1101 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1102 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1103 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1104 'reverse', 'sort']
1105
1106 dir(module) continues to return only the module's attributes, though.
1107
Tim Petersbdee63f2001-09-02 03:40:59 +00001108- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001109 than raising OverflowError. This is a partial implementation of PEP
1110 237. You can use -Wdefault::OverflowWarning to enable a warning for
1111 this situation, and -Werror::OverflowWarning to revert to the old
1112 OverflowError exception.
1113
Guido van Rossum61c345f2001-09-04 03:26:15 +00001114- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001115 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001116 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1117 -Qold, meaning the / operator has its classic meaning and no
1118 warnings are issued. Using -Qwarn issues a run-time warning about
1119 all uses of classic division for int and long arguments; -Qwarnall
1120 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001121 (for use with fixdiv.py).
1122 [Note: the remainder of this paragraph (preserved below) became
1123 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1124 <obsolete>
1125 Using -Qnew is questionable; it turns on new division by default, but
1126 only in the __main__ module. You can usefully combine -Qwarn or
1127 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1128 warns about classic division everywhere else.
1129 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001130
Tim Petersbdee63f2001-09-02 03:40:59 +00001131- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001132 long, float, str, unicode, and tuple. (The types complex, list and
1133 dictionary can also be subclassed; this was introduced earlier.)
1134 Note that restrictions apply when subclassing immutable built-in
1135 types: you can only affect the value of the instance by overloading
1136 __new__. You can add mutable attributes, and the subclass instances
1137 will have a __dict__ attribute, but you cannot change the "value"
1138 (as implemented by the base class) of an immutable subclass instance
1139 once it is created.
1140
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001141- The dictionary constructor now takes an optional argument, a
1142 mapping-like object, and initializes the dictionary from its
1143 (key, value) pairs.
1144
Tim Petersbdee63f2001-09-02 03:40:59 +00001145- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001146 "cooperative super calls" in a multiple inheritance setting. For an
1147 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1148
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001149- A new built-in type, property, has been added. This enables the
1150 creation of "properties". These are attributes implemented by
1151 getter and setter functions (or only one of these for read-only or
1152 write-only attributes), without the need to override __getattr__.
1153 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001154
Tim Petersbdee63f2001-09-02 03:40:59 +00001155- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001156 liberalized, to allow leading zeroes. Examples of literals now
1157 legal that were SyntaxErrors before:
1158
1159 00.0 0e3 0100j 07.5 00000000000000000008.
1160
Tim Petersbdee63f2001-09-02 03:40:59 +00001161- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001162 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1163
Tim Petersedc99312001-08-22 21:36:50 +00001164Library
1165
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001166- telnetlib includes symbolic names for the options, and support for
1167 setting an option negotiation callback.
1168
Tim Petersa40c7932001-09-05 22:36:56 +00001169- The new C standard no longer requires that math libraries set errno to
1170 ERANGE on overflow. For platform libraries that exploit this new
1171 freedom, Python's overflow-checking was wholly broken. A new overflow-
1172 checking scheme attempts to repair that, but may not be reliable on all
1173 platforms (C doesn't seem to provide anything both useful and portable
1174 in this area anymore).
1175
Martin v. Löwis44f86962001-09-05 13:44:54 +00001176- Asynchronous timeout actions are available through the new class
1177 threading.Timer.
1178
Tim Peters78526162001-09-05 00:53:45 +00001179- math.log and math.log10 now return sensible results for even huge
1180 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1181
Tim Petersbdee63f2001-09-02 03:40:59 +00001182- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001183 currently held. See the docs for the imp module.
1184
Tim Petersbdee63f2001-09-02 03:40:59 +00001185- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001186 dumps containing ints written on platforms where Python ints are 8 bytes.
1187 When read on a box where Python ints are 4 bytes, such values are
1188 converted to Python longs.
1189
Tim Petersbdee63f2001-09-02 03:40:59 +00001190- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001191 code objects is no longer allowed. This plugs a security hole.
1192
Steve Purcell6091cd62001-09-06 16:05:17 +00001193- unittest.TestResult instances no longer store references to tracebacks
1194 generated by test failures. This prevents unexpected dangling references
1195 to objects that should be garbage collected between tests.
1196
Tim Petersedc99312001-08-22 21:36:50 +00001197Tools
1198
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001199- Tools/scripts/fixdiv.py has been added which can be used to fix
1200 division operators as per PEP 238.
1201
Tim Petersedc99312001-08-22 21:36:50 +00001202Build
1203
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001204- If you are an adventurous person using Mac OS X you may want to look at
1205 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1206 application, which can be used for experimenting with Carbon or Cocoa.
1207 Discussion of this on pythonmac-sig, please.
1208
Tim Peters7eea37e2001-09-04 22:08:56 +00001209C API
1210
1211- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001212
Tim Peters9fffa3e2001-09-04 05:14:19 +00001213- Note that PyLong_AsDouble can fail! This has always been true, but no
1214 callers checked for it. It's more likely to fail now, because overflow
1215 errors are properly detected now. The proper way to check:
1216
1217 double x = PyLong_AsDouble(some_long_object);
1218 if (x == -1.0 && PyErr_Occurred()) {
1219 /* The conversion failed. */
1220 }
1221
Tim Petersbdee63f2001-09-02 03:40:59 +00001222- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001223 compile but will not participate in GC. To upgrade an extension
1224 module:
1225
1226 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001227
Neil Schemenauer4042c692001-08-30 15:38:01 +00001228 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1229 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001230
Neil Schemenauer4042c692001-08-30 15:38:01 +00001231 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1232 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001233
Neil Schemenauer4042c692001-08-30 15:38:01 +00001234 - remove PyGC_HEAD_SIZE from object size calculations
1235
1236 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1237
Tim Petersbdee63f2001-09-02 03:40:59 +00001238- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001239 These can be used safely to construct string objects from a
1240 sprintf-style format string (similar to the format string supported
1241 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001242
Tim Petersedc99312001-08-22 21:36:50 +00001243New platforms
1244
Tim Petersb7da0902001-09-02 23:01:43 +00001245- Stephen Hansen contributed patches sufficient to get a clean compile
1246 under Borland C (Windows), but he reports problems running it and ran
1247 out of time to complete the port. Volunteers? Expect a MemoryError
1248 when importing the types module; this is probably shallow, and
1249 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001250
Tim Petersedc99312001-08-22 21:36:50 +00001251Tests
1252
1253Windows
1254
Tim Peters6e13a562001-09-06 00:32:15 +00001255- Large file support is now enabled on Win32 platforms as well as on
1256 Win64. This means that, for example, you can use f.tell() and f.seek()
1257 to manipulate files larger than 2 gigabytes (provided you have enough
1258 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001259 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1260 filesize limit, and large file support makes no difference there.
1261 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1262 NTFS has no practical limit on file size, and files of any size can be
1263 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001264
Tim Petersbdee63f2001-09-02 03:40:59 +00001265- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001266 points to command.com (patch from Brian Quinlan).
1267
Tim Petersedc99312001-08-22 21:36:50 +00001268
Tim Peters20f51a72001-07-21 02:31:40 +00001269What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001270Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001271===========================
1272
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001273Build
1274
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001275- Tim Peters developed a brand new Windows installer using Wise 8.1,
1276 generously donated to us by Wise Solutions.
1277
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001278- configure supports a new option --enable-unicode, with the values
1279 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1280 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001281
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001282- A new configure option --enable-framework builds a Mac OS X framework,
1283 which "make frameworkinstall" will install. This provides a starting
1284 point for more mac-like functionality, join pythonmac-sig@python.org
1285 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001286
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001287- The NeXT platform is no longer supported.
1288
1289- The `new' module is now statically linked.
1290
Tim Peters0afb6092001-08-15 06:06:44 +00001291Tools
1292
1293- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001294 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001295 the module docstring for details.
1296
Tim Peters20f51a72001-07-21 02:31:40 +00001297Tests
1298
Tim Peters5e824c32001-08-12 22:25:01 +00001299- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001300 platforms, allowing to give clearer test result output. regrtest
1301 also has optional --use/-u switch to run normally disabled tests
1302 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001303
Tim Peters20f51a72001-07-21 02:31:40 +00001304- Several new tests in the standard test suite, with special thanks to
1305 Nick Mathewson.
1306
1307Core
1308
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001309- The floor division operator // has been added as outlined in PEP
1310 238. The / operator still provides classic division (and will until
1311 Python 3.0) unless "from __future__ import division" is included, in
1312 which case the / operator will provide true division. The operator
1313 module provides truediv() and floordiv() functions. Augmented
1314 assignment variants are included, as are the equivalent overloadable
1315 methods and C API methods. See the PEP for a full discussion:
1316 <http://python.sf.net/peps/pep-0238.html>
1317
Tim Peters6cd6a822001-08-17 22:11:27 +00001318- Future statements are now effective in simulated interactive shells
1319 (like IDLE). This should "just work" by magic, but read Michael
1320 Hudson's "Future statements in simulated shells" PEP 264 for full
1321 details: <http://python.sf.net/peps/pep-0264.html>.
1322
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001323- The type/class unification (PEP 252-253) was integrated into the
1324 trunk and is not so tentative any more (the exact specification of
1325 some features is still tentative). A lot of work has done on fixing
1326 bugs and adding robustness and features (performance still has to
1327 come a long way).
1328
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001329- Warnings about a mismatch in the Python API during extension import
1330 now use the Python warning framework (which makes it possible to
1331 write filters for these warnings).
1332
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001333- A function's __dict__ (aka func_dict) will now always be a
1334 dictionary. It used to be possible to delete it or set it to None,
1335 but now both actions raise TypeErrors. It is still legal to set it
1336 to a dictionary object. Getting func.__dict__ before any attributes
1337 have been assigned now returns an empty dictionary instead of None.
1338
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001339- A new command line option, -E, was added which disables the use of
1340 all environment variables, or at least those that are specifically
1341 significant to Python. Usually those have a name starting with
1342 "PYTHON". This was used to fix a problem where the tests fail if
1343 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1344 older distribution.
1345
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001346Library
1347
Tim Peters5e824c32001-08-12 22:25:01 +00001348- New class Differ and new functions ndiff() and restore() in difflib.py.
1349 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001350 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001351
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001352- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1353 value using the minimal quoting required for the value; more
1354 reliable than using xml.sax.saxutils.escape() for attribute values.
1355
1356- Readline completion support for cmd.Cmd was added.
1357
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001358- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1359
1360- Added function threading.BoundedSemaphore()
1361
1362- Added Ka-Ping Yee's cgitb.py module.
1363
1364- The `new' module now exposes the CO_xxx flags.
1365
Martin v. Löwis560da622001-11-24 09:24:51 +00001366- The gc module offers the get_referents function.
1367
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001368New platforms
1369
1370C API
1371
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001372- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1373 which provide a cross-platform implementations for the
1374 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1375 the standard sprintf() and vsprintf() C lib APIs, these versions
1376 apply bounds checking on the used buffer which enhances protection
1377 against buffer overruns.
1378
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001379- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001380 and extensions using different Unicode widths is rendered next to
1381 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001382 will result in an ImportError. Unicode extensions writers must make
1383 sure to check the Unicode width compatibility in their extensions by
1384 using at least one of the mangled Unicode APIs in the extension.
1385
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001386- Two new flags METH_NOARGS and METH_O are available in method definition
1387 tables to simplify implementation of methods with no arguments and a
1388 single untyped argument. Calling such methods is more efficient than
1389 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1390 deprecated.
1391
Tim Petersc1731372001-08-04 08:12:36 +00001392Windows
1393
1394- "import module" now compiles module.pyw if it exists and nothing else
1395 relevant is found.
1396
Tim Peters20f51a72001-07-21 02:31:40 +00001397
Guido van Rossum55a78992001-07-17 17:22:32 +00001398What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001399Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001400===========================
1401
1402Core
Tim Petersa814db52001-05-14 07:05:58 +00001403
Tim Peters6d6c1a32001-08-02 04:15:00 +00001404- TENTATIVELY, a large amount of code implementing much of what's
1405 described in PEP 252 (Making Types Look More Like Classes) and PEP
1406 253 (Subtyping Built-in Types) was added. This will be released
1407 with Python 2.2a1. Documentation will be provided separately
1408 through http://www.python.org/2.2/. The purpose of releasing this
1409 with Python 2.2a1 is to test backwards compatibility. It is
1410 possible, though not likely, that a decision is made not to release
1411 this code as part of 2.2 final, if any serious backwards
1412 incompapatibilities are found during alpha testing that cannot be
1413 repaired.
1414
Guido van Rossum55a78992001-07-17 17:22:32 +00001415- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001416 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001417 more 'yield' statements. See PEP 255. Since this adds a new
1418 keyword to the language, this feature must be enabled by including a
1419 future statement: "from __future__ import generators" (see PEP 236).
1420 Generators will become a standard feature in a future release
1421 (probably 2.3). Without this future statement, 'yield' remains an
1422 ordinary identifier, but a warning is issued each time it is used.
1423 (These warnings currently don't conform to the warnings framework of
1424 PEP 230; we intend to fix this in 2.2a2.)
1425
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001426- The UTF-16 codec was modified to be more RFC compliant. It will now
1427 only remove BOM characters at the start of the string and then
1428 only if running in native mode (UTF-16-LE and -BE won't remove a
1429 leading BMO character).
1430
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001431- Strings now have a new method .decode() to complement the already
1432 existing .encode() method. These two methods provide direct access
1433 to the corresponding decoders and encoders of the registered codecs.
1434
1435 To enhance the usability of the .encode() method, the special
1436 casing of Unicode object return values was dropped (Unicode objects
1437 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001438
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001439 Both methods will now return whatever the codec in charge of the
1440 requested encoding returns as object, e.g. Unicode codecs will
1441 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1442 will return u"äöü"). This enables codec writer to create codecs
1443 for various simple to use conversions.
1444
1445 New codecs were added to demonstrate these new features (the .encode()
1446 and .decode() columns indicate the type of the returned objects):
1447
1448 Name | .encode() | .decode() | Description
1449 ----------------------------------------------------------------------
1450 uu | string | string | UU codec (e.g. for email)
1451 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001452 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001453 zlib | string | string | zlib compression
1454 hex | string | string | 2-byte hex codec
1455 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1456
Mark Hammond2a0af792001-05-14 03:09:36 +00001457- Some operating systems now support the concept of a default Unicode
1458 encoding for file system operations. Notably, Windows supports 'mbcs'
1459 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001460 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001461 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001462
1463 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001464 functions that return filenames (such as os.listdir()) to return Python
1465 string objects pre-encoded using the default file system encoding for
1466 the platform. As this encoding is likely to be different from Python's
1467 default encoding, converting this name to a Unicode object before passing
1468 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001469 would attempt to use its default encoding (generally ASCII) rather than
1470 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001471
Tim Petersa814db52001-05-14 07:05:58 +00001472 In general, this change simply removes surprises when working with
1473 Unicode and the file system, making these operations work as you expect,
1474 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001475 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001476
Tim Peters61dff2b2001-05-08 15:43:37 +00001477- Float (and complex) literals in source code were evaluated to full
1478 precision only when running from a .py file; the same code loaded from a
1479 .pyc (or .pyo) file could suffer numeric differences starting at about the
1480 12th significant decimal digit. For example, on a machine with IEEE-754
1481 floating arithmetic,
1482
1483 x = 9007199254740992.0
1484 print long(x)
1485
1486 printed 9007199254740992 if run directly from .py, but 9007199254740000
1487 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1488 str(float) instead of repr(float) when building code objects. marshal
1489 now uses repr(float) instead, which should reproduce floats to full
1490 machine precision (assuming the platform C float<->string I/O conversion
1491 functions are of good quality).
1492
1493 This may cause floating-point results to change in some cases, and
1494 usually for the better, but may also cause numerically unstable
1495 algorithms to break.
1496
Tim Peters2f228e72001-05-13 00:19:31 +00001497- The implementation of dicts suffers fewer collisions, which has speed
1498 benefits. However, the order in which dict entries appear in dict.keys(),
1499 dict.values() and dict.items() may differ from previous releases for a
1500 given dict. Nothing is defined about this order, so no program should
1501 rely on it. Nevertheless, it's easy to write test cases that rely on the
1502 order by accident, typically because of printing the str() or repr() of a
1503 dict to an "expected results" file. See Lib/test/test_support.py's new
1504 sortdict(dict) function for a simple way to display a dict in sorted
1505 order.
1506
Tim Peters7a3bfc32001-06-12 01:22:22 +00001507- Many other small changes to dicts were made, resulting in faster
1508 operation along the most common code paths.
1509
Guido van Rossum10315822001-05-01 20:54:30 +00001510- Dictionary objects now support the "in" operator: "x in dict" means
1511 the same as dict.has_key(x).
1512
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001513- The update() method of dictionaries now accepts generic mapping
1514 objects. Specifically the argument object must support the .keys()
1515 and __getitem__() methods. This allows you to say, for example,
1516 {}.update(UserDict())
1517
Guido van Rossum10315822001-05-01 20:54:30 +00001518- Iterators were added; this is a generalized way of providing values
1519 to a for loop. See PEP 234. There's a new built-in function iter()
1520 to return an iterator. There's a new protocol to get the next value
1521 from an iterator using the next() method (in Python) or the
1522 tp_iternext slot (in C). There's a new protocol to get iterators
1523 using the __iter__() method (in Python) or the tp_iter slot (in C).
1524 Iterating (i.e. a for loop) over a dictionary generates its keys.
1525 Iterating over a file generates its lines.
1526
Tim Petersf553f892001-05-01 20:45:31 +00001527- The following functions were generalized to work nicely with iterator
1528 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001529 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001530 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1531 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001532 join() method of strings
1533 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001534 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1535 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001536 right-hand side of assignment statements with multiple targets, such as
1537 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001538
Tim Petersd85e1022001-05-11 21:51:48 +00001539- Accessing module attributes is significantly faster (for example,
1540 random.random or os.path or yourPythonModule.yourAttribute).
1541
Tim Peterse63415e2001-05-08 04:38:29 +00001542- Comparing dictionary objects via == and != is faster, and now works even
1543 if the keys and values don't support comparisons other than ==.
1544
Tim Peters95bf9392001-05-10 08:32:44 +00001545- Comparing dictionaries in ways other than == and != is slower: there were
1546 insecurities in the dict comparison implementation that could cause Python
1547 to crash if the element comparison routines for the dict keys and/or
1548 values mutated the dicts. Making the code bulletproof slowed it down.
1549
Tim Peterseb28ef22001-06-02 05:27:19 +00001550- Collisions in dicts are resolved via a new approach, which can help
1551 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001552 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001553 faster now. Thanks to Christian Tismer for pointing out the cause and
1554 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001555
Tim Peters52e155e2001-06-16 05:42:57 +00001556- repr() is much faster for large containers (dict, list, tuple).
1557
1558
Tim Petersa814db52001-05-14 07:05:58 +00001559Library
1560
Fred Drake960fdf92001-07-20 18:38:26 +00001561- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1562 were added to the string module. These a locale-indenpendent
1563 constants, unlike letters, lowercase, and uppercase. These are now
1564 use in appropriate locations in the standard library.
1565
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001566- The flags used in dlopen calls can now be configured using
1567 sys.setdlopenflags and queried using sys.getdlopenflags.
1568
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001569- Fredrik Lundh's xmlrpclib is now a standard library module. This
1570 provides full client-side XML-RPC support. In addition,
1571 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1572 one asyncore-based). Thanks to Eric Raymond for the documentation.
1573
Guido van Rossum643d3912001-07-05 14:46:25 +00001574- The xrange() object is simplified: it no longer supports slicing,
1575 repetition, comparisons, efficient 'in' checking, the tolist()
1576 method, or the start, stop and step attributes. See PEP 260.
1577
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001578- A new function fnmatch.filter to filter lists of file names was added.
1579
Barry Warsawffd674d2001-05-22 16:00:10 +00001580- calendar.py uses month and day names based on the current locale.
1581
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001582- strop is now *really* obsolete (this was announced before with 1.6),
1583 and issues DeprecationWarning when used (except for the four items
1584 that are still imported into string.py).
1585
Tim Petersa814db52001-05-14 07:05:58 +00001586- Cookie.py now sorts key+value pairs by key in output strings.
1587
1588- pprint.isrecursive(object) didn't correctly identify recursive objects.
1589 Now it does.
1590
Tim Peters95b3f782001-05-14 18:39:41 +00001591- pprint functions now much faster for large containers (tuple, list, dict).
1592
Tim Peters7b9542a2001-06-10 23:40:19 +00001593- New 'q' and 'Q' format codes in the struct module, corresponding to C
1594 types "long long" and "unsigned long long" (on Windows, __int64). In
1595 native mode, these can be used only when the platform C compiler supports
1596 these types (when HAVE_LONG_LONG is #define'd by the Python config
1597 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001598 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1599 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001600
Guido van Rossum83213cc2001-06-12 16:48:52 +00001601- The site module installs a new built-in function 'help' that invokes
1602 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1603 it displays a message reminding the user to use 'help()' or
1604 'help(object)'.
1605
Tim Petersa814db52001-05-14 07:05:58 +00001606Tests
1607
1608- New test_mutants.py runs dict comparisons where the key and value
1609 comparison operators mutute the dicts randomly during comparison. This
1610 rapidly causes Python to crash under earlier releases (not for the faint
1611 of heart: it can also cause Win9x to freeze or reboot!).
1612
1613- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001614 pprint.isreadable() return sensible results. Also verifies that simple
1615 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001616
Tim Peters4324aa32001-05-28 22:30:08 +00001617C API
1618
1619- Removed the unused last_is_sticky argument from the internal
1620 _PyTuple_Resize(). If this affects you, you were cheating.
1621
1622
Guido van Rossum55a78992001-07-17 17:22:32 +00001623======================================================================
1624
1625
Guido van Rossumffe13be2001-04-16 18:46:45 +00001626What's New in Python 2.1 (final)?
1627=================================
1628
1629We only changed a few things since the last release candidate, all in
1630Python library code:
1631
1632- A bug in the locale module was fixed that affected locales which
1633 define no grouping for numeric formatting.
1634
1635- A few bugs in the weakref module's implementations of weak
1636 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1637 and the test suite was updated to check for these bugs.
1638
1639- An old bug in the os.path.walk() function (introduced in Python
1640 2.0!) was fixed: a non-existent file would cause an exception
1641 instead of being ignored.
1642
1643- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1644 PyChecker.
1645
1646
Guido van Rossum5b08f132001-04-16 02:05:23 +00001647What's New in Python 2.1c2?
1648===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001649
Guido van Rossum5b08f132001-04-16 02:05:23 +00001650A flurry of small changes, and one showstopper fixed in the nick of
1651time made it necessary to release another release candidate. The list
1652here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001653
Guido van Rossum5b08f132001-04-16 02:05:23 +00001654Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001655
Guido van Rossum5b08f132001-04-16 02:05:23 +00001656- Tim discovered a nasty bug in the dictionary code, caused by
1657 PyDict_Next() calling dict_resize(), and the GC code's use of
1658 PyDict_Next() violating an assumption in dict_items(). This was
1659 fixed with considerable amounts of band-aid, but the net effect is a
1660 saner and more robust implementation.
1661
1662- Made a bunch of symbols static that were accidentally global.
1663
1664Build and Ports
1665
1666- The setup.py script didn't check for a new enough version of zlib
1667 (1.1.3 is needed). Now it does.
1668
1669- Changed "make clean" target to also remove shared libraries.
1670
1671- Added a more general warning about the SGI Irix optimizer to README.
1672
1673Library
1674
1675- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1676 omitted the slash between host and file.html.
1677
1678- The mailbox module's _Mailbox class contained a completely broken
1679 and undocumented seek() method. Ripped it out.
1680
1681- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1682 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1683
1684- Fixed a few last-minute bugs in unittest.
1685
1686Extensions
1687
1688- Reverted the patch to the OpenSSL code in socketmodule.c to support
1689 RAND_status() and the EGD, and the subsequent patch that tried to
1690 fix it for pre-0.9.5 versions; the problem with the patch is that on
1691 some systems it issues a warning whenever socket is imported, and
1692 that's unacceptable.
1693
1694Tests
1695
1696- Fixed the pickle tests to work with "import test.test_pickle".
1697
1698- Tweaked test_locale.py to actually run the test Windows.
1699
1700- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1701 not "wb" (which is not a valid mode at all).
1702
1703- Fix pstats browser crashes. Import readline if it exists to make
1704 the user interface nicer.
1705
1706- Add "import thread" to the top of test modules that import the
1707 threading module (test_asynchat and test_threadedtempfile). This
1708 prevents test failures caused by a broken threading module resulting
1709 from a previously caught failed import.
1710
1711- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1712 needed on some platforms (e.g. Solaris 8) when the tests are run
1713 twice in succession.
1714
1715- Skip rather than fail test_sunaudiodev if no audio device is found.
1716
1717
1718What's New in Python 2.1c1?
1719===========================
1720
1721This list was significantly updated when 2.1c2 was released; the 2.1c1
1722release didn't mention most changes that were actually part of 2.1c1:
1723
1724Legal
1725
1726- Copyright was assigned to the Python Software Foundation (PSF) and a
1727 PSF license (very similar to the CNRI license) was added.
1728
1729- The CNRI copyright notice was updated to include 2001.
1730
1731Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001732
Guido van Rossumc9932722001-04-12 02:31:27 +00001733- After a public outcry, assignment to __debug__ is no longer illegal;
1734 instead, a warning is issued. It will become illegal in 2.2.
1735
Guido van Rossum5b08f132001-04-16 02:05:23 +00001736- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1737 "%#x" now always prepends "0x", even if the value is zero.
1738
1739- Fixed some nits in the bytecode compiler.
1740
1741- Fixed core dumps when calling certain kinds of non-functions.
1742
1743- Fixed various core dumps caused by reference count bugs.
1744
1745Build and Ports
1746
1747- Use INSTALL_SCRIPT to install script files.
1748
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001749- New port: SCO Unixware 7, by Billy G. Allie.
1750
Guido van Rossum5b08f132001-04-16 02:05:23 +00001751- Updated RISCOS port.
1752
1753- Updated BeOS port and notes.
1754
1755- Various other porting problems resolved.
1756
1757Library
1758
1759- The TERMIOS and SOCKET modules are now truly obsolete and
1760 unnecessary. Their symbols are incorporated in the termios and
1761 socket modules.
1762
1763- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1764 better tests for pickling.
1765
1766- threading: make Condition.wait() robust against KeyboardInterrupt.
1767
1768- zipfile: add support to zipfile to support opening an archive
1769 represented by an open file rather than a file name. Fix bug where
1770 the archive was not properly closed. Fixed a bug in this bugfix
1771 where flush() was called for a read-only file.
1772
1773- imputil: added an uninstall() method to the ImportManager.
1774
1775- Canvas: fixed bugs in lower() and tkraise() methods.
1776
1777- SocketServer: API change (added overridable close_request() method)
1778 so that the TCP server can explicitly close the request.
1779
1780- pstats: Eric Raymond added a simple interactive statistics browser,
1781 invoked when the module is run as a script.
1782
1783- locale: fixed a problem in format().
1784
1785- webbrowser: made it work when the BROWSER environment variable has a
1786 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1787 KDE 2. Fixed some other nits.
1788
1789- unittest: changes to allow using a different exception than
1790 AssertionError, and added a few more function aliases. Some other
1791 small changes.
1792
1793- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1794
1795- asynchat: fixed a critical bug in asynchat that slipped through the
1796 2.1b2 release. Fixed another rare bug.
1797
1798- Fix some unqualified except: clauses (always a bad code example).
1799
1800XML
1801
1802- pyexpat: new API get_version_string().
1803
1804- Fixed some minidom bugs.
1805
1806Extensions
1807
1808- Fixed a core dump in _weakref. Removed the weakref.mapping()
1809 function (it adds nothing to the API).
1810
1811- Rationalized the use of header files in the readline module, to make
1812 it compile (albeit with some warnings) with the very recent readline
1813 4.2, without breaking for earlier versions.
1814
1815- Hopefully fixed a buffering problem in linuxaudiodev.
1816
1817- Attempted a fix to make the OpenSSL support in the socket module
1818 work again with pre-0.9.5 versions of OpenSSL.
1819
1820Tests
1821
1822- Added a test case for asynchat and asyncore.
1823
1824- Removed coupling between tests where one test failing could break
1825 another.
1826
1827Tools
1828
1829- Ping added an interactive help browser to pydoc, fixed some nits
1830 in the rest of the pydoc code, and added some features to his
1831 inspect module.
1832
1833- An updated python-mode.el version 4.1 which integrates Ken
1834 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1835 much nicer in XEmacs and Emacs. When stepping through your program
1836 with pdb, in either the shell window or the *Python* window, the
1837 source file and line will be tracked by an arrow. Very cool!
1838
1839- IDLE: syntax warnings in interactive mode are changed into errors.
1840
1841- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001842 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001843
1844- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001845
Barry Warsaw11e89c72001-04-11 20:37:57 +00001846
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001847What's New in Python 2.1 beta 2?
1848================================
1849
Guido van Rossum053ae352001-03-22 14:17:21 +00001850(Unlisted are many fixed bugs, more documentation, etc.)
1851
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001852Core language, builtins, and interpreter
1853
Guido van Rossum053ae352001-03-22 14:17:21 +00001854- The nested scopes work (enabled by "from __future__ import
1855 nested_scopes") is completed; in particular, the future now extends
1856 into code executed through exec, eval() and execfile(), and into the
1857 interactive interpreter.
1858
1859- When calling a base class method (e.g. BaseClass.__init__(self)),
1860 this is now allowed even if self is not strictly spoken a class
1861 instance (e.g. when using metaclasses or the Don Beaudry hook).
1862
1863- Slice objects are now comparable but not hashable; this prevents
1864 dict[:] from being accepted but meaningless.
1865
1866- Complex division is now calculated using less braindead algorithms.
1867 This doesn't change semantics except it's more likely to give useful
1868 results in extreme cases. Complex repr() now uses full precision
1869 like float repr().
1870
1871- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1872
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001873- It is illegal to assign to the name __debug__, which is set when the
1874 interpreter starts. It is effectively a compile-time constant.
1875
1876- A warning will be issued if a global statement for a variable
1877 follows a use or assignment of that variable.
1878
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001879Standard library
1880
Guido van Rossum053ae352001-03-22 14:17:21 +00001881- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1882 inspired by JUnit), is now part of the standard library. You now
1883 have a choice of two testing frameworks: unittest requires you to
1884 write testcases as separate code, doctest gathers them from
1885 docstrings. Both approaches have their advantages and
1886 disadvantages.
1887
1888- A new module Tix was added, which wraps the Tix extension library
1889 for Tk. With that module, it is not necessary to statically link
1890 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1891 require" command. See Demo/tix/.
1892
1893- tzparse.py is now obsolete.
1894
1895- In gzip.py, the seek() and tell() methods are removed -- they were
1896 non-functional anyway, and it's better if callers can test for their
1897 existence with hasattr().
1898
1899Python/C API
1900
1901- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1902 that's already in the dictionary during a PyDict_Next() iteration.
1903 This used to fail occasionally when a dictionary resize operation
1904 could be triggered that would rehash all the keys. All other
1905 modifications to the dictionary are still off-limits during a
1906 PyDict_Next() iteration!
1907
1908- New extended APIs related to passing compiler variables around.
1909
1910- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1911 implement isinstance() and issubclass().
1912
1913- Py_BuildValue() now has a "D" conversion to create a Python complex
1914 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001915
Fred Drake4e262a92001-03-22 18:26:47 +00001916- Extensions types which support weak references must now set the
1917 field allocated for the weak reference machinery to NULL themselves;
1918 this is done to avoid the cost of checking each object for having a
1919 weakly referencable type in PyObject_INIT(), since most types are
1920 not weakly referencable.
1921
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001922- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1923 free variables and cell variables to and from the frame's f_locals.
1924
1925- Variants of several functions defined in pythonrun.h have been added
1926 to support the nested_scopes future statement. The variants all end
1927 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1928 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1929 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001930 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001931
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001932Distutils
1933
1934- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1935 into the release tree.
1936
Tim Peters0e57abf2001-05-02 07:39:38 +00001937- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001938 (an uninstaller, more customization of the installer's display)
1939
1940- from Jack Jansen: added Mac-specific code to generate a dialog for
1941 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001942 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001943 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001944
1945- added 'platforms' and 'keywords' to the set of metadata that can be
1946 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001947
1948- applied patches from Jason Tishler to make the compiler class work with
1949 Cygwin.
1950
1951
Tim Peters2fe289a2001-03-01 22:19:38 +00001952What's New in Python 2.1 beta 1?
1953================================
Tim Petersd66595f2001-02-04 03:09:53 +00001954
1955Core language, builtins, and interpreter
1956
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001957- Following an outcry from the community about the amount of code
1958 broken by the nested scopes feature introduced in 2.1a2, we decided
1959 to make this feature optional, and to wait until Python 2.2 (or at
1960 least 6 months) to make it standard. The option can be enabled on a
1961 per-module basis by adding "from __future__ import nested_scopes" at
1962 the beginning of a module (before any other statements, but after
1963 comments and an optional docstring). See PEP 236 (Back to the
1964 __future__) for a description of the __future__ statement. PEP 227
1965 (Statically Nested Scopes) has been updated to reflect this change,
1966 and to clarify the semantics in a number of endcases.
1967
1968- The nested scopes code, when enabled, has been hardened, and most
1969 bugs and memory leaks in it have been fixed.
1970
1971- Compile-time warnings are now generated for a number of conditions
1972 that will break or change in meaning when nested scopes are enabled:
1973
1974 - Using "from...import *" or "exec" without in-clause in a function
1975 scope that also defines a lambda or nested function with one or
1976 more free (non-local) variables. The presence of the import* or
1977 bare exec makes it impossible for the compiler to determine the
1978 exact set of local variables in the outer scope, which makes it
1979 impossible to determine the bindings for free variables in the
1980 inner scope. To avoid the warning about import *, change it into
1981 an import of explicitly name object, or move the import* statement
1982 to the global scope; to avoid the warning about bare exec, use
1983 exec...in... (a good idea anyway -- there's a possibility that
1984 bare exec will be deprecated in the future).
1985
1986 - Use of a global variable in a nested scope with the same name as a
1987 local variable in a surrounding scope. This will change in
1988 meaning with nested scopes: the name in the inner scope will
1989 reference the variable in the outer scope rather than the global
1990 of the same name. To avoid the warning, either rename the outer
1991 variable, or use a global statement in the inner function.
1992
Neil Schemenauera35c6882001-02-27 04:45:05 +00001993- An optional object allocator has been included. This allocator is
1994 optimized for Python objects and should be faster and use less memory
1995 than the standard system allocator. It is not enabled by default
1996 because of possible thread safety problems. The allocator is only
1997 protected by the Python interpreter lock and it is possible that some
1998 extension modules require a thread safe allocator. The object
1999 allocator can be enabled by providing the "--with-pymalloc" option to
2000 configure.
2001
Tim Petersd66595f2001-02-04 03:09:53 +00002002Standard library
2003
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002004- pyexpat now detects the expat version if expat.h defines it. A
2005 number of additional handlers are provided, which are only available
2006 since expat 1.95. In addition, the methods SetParamEntityParsing and
2007 GetInputContext of Parser objects are available with 1.95.x
2008 only. Parser objects now provide the ordered_attributes and
2009 specified_attributes attributes. A new module expat.model was added,
2010 which offers a number of additional constants if 1.95.x is used.
2011
2012- xml.dom offers the new functions registerDOMImplementation and
2013 getDOMImplementation.
2014
2015- xml.dom.minidom offers a toprettyxml method. A number of DOM
2016 conformance issues have been resolved. In particular, Element now
2017 has an hasAttributes method, and the handling of namespaces was
2018 improved.
2019
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002020- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2021 getting information about live Python code, and pydoc.py, a module
2022 for interactively converting docstrings to HTML or text.
2023 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002024 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002025 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2026 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002027
Tim Peters1eff7962001-03-01 02:31:33 +00002028- New library module difflib.py, primarily packaging the SequenceMatcher
2029 class at the heart of the popular ndiff.py file-comparison tool.
2030
2031- doctest.py (a framework for verifying Python code examples in docstrings)
2032 is now part of the std library.
2033
Tim Petersd66595f2001-02-04 03:09:53 +00002034Windows changes
2035
Guido van Rossume3955a82001-03-02 14:05:59 +00002036- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2037 small GUI that lets you browse the module docstrings using your
2038 default web browser.
2039
Tim Peters1eff7962001-03-01 02:31:33 +00002040- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2041 Platforms) is implemented. See
2042
2043 http://python.sourceforge.net/peps/pep-0235.html
2044
2045 for full details, especially the "Current Lower-Left Semantics" section.
2046 The new Windows import rules are simpler than before:
2047
2048 A. If the PYTHONCASEOK environment variable exists, same as
2049 before: silently accept the first case-insensitive match of any
2050 kind; raise ImportError if none found.
2051
2052 B. Else search sys.path for the first case-sensitive match; raise
2053 ImportError if none found.
2054
2055 The same rules have been implented on other platforms with case-
2056 insensitive but case-preserving filesystems too (including Cygwin, and
2057 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002058
Tim Peters25a9ce32001-02-19 07:06:36 +00002059- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2060 what it's supposed to do (and does do under NT and 2000) via direct
2061 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002062 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002063 all Win9x systems before.
2064
Tim Peters1eff7962001-03-01 02:31:33 +00002065- Build: Subproject _test (effectively) renamed to _testcapi.
2066
Tim Peters2fe289a2001-03-01 22:19:38 +00002067New platforms
2068
2069- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2070 Thanks to Steven Majewski!
2071
2072- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2073 Tishler!
2074
Guido van Rossum9089b272001-03-02 06:49:50 +00002075- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2076 Schwertberger! See RISCOS/README for more information -- it seems
2077 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002078 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002079
Tim Peters25a9ce32001-02-19 07:06:36 +00002080
Tim Petersd7b5e882001-01-25 03:36:26 +00002081What's New in Python 2.1 alpha 2?
2082=================================
Tim Peters40ead762001-01-27 05:35:26 +00002083
Tim Petersd7b5e882001-01-25 03:36:26 +00002084Core language, builtins, and interpreter
2085
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002086- Scopes nest. If a name is used in a function or class, but is not
2087 local, the definition in the nearest enclosing function scope will
2088 be used. One consequence of this change is that lambda statements
2089 could reference variables in the namespaces where the lambda is
2090 defined. In some unusual cases, this change will break code.
2091
2092 In all previous version of Python, names were resolved in exactly
2093 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002094 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002095 function A is defined within a function B, the names bound in B are
2096 not visible in A. The new rules make names bound in B visible in A,
2097 unless A contains a name binding that hides the binding in B.
2098
2099 Section 4.1 of the reference manual describes the new scoping rules
2100 in detail. The test script in Lib/test/test_scope.py demonstrates
2101 some of the effects of the change.
2102
2103 The new rules will cause existing code to break if it defines nested
2104 functions where an outer function has local variables with the same
2105 name as globals or builtins used by the inner function. Example:
2106
2107 def munge(str):
2108 def helper(x):
2109 return str(x)
2110 if type(str) != type(''):
2111 str = helper(str)
2112 return str.strip()
2113
2114 Under the old rules, the name str in helper() is bound to the
2115 builtin function str(). Under the new rules, it will be bound to
2116 the argument named str and an error will occur when helper() is
2117 called.
2118
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002119- The compiler will report a SyntaxError if "from ... import *" occurs
2120 in a function or class scope. The language reference has documented
2121 that this case is illegal, but the compiler never checked for it.
2122 The recent introduction of nested scope makes the meaning of this
2123 form of name binding ambiguous. In a future release, the compiler
2124 may allow this form when there is no possibility of ambiguity.
2125
Tim Peters40ead762001-01-27 05:35:26 +00002126- repr(string) is easier to read, now using hex escapes instead of octal,
2127 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2128
2129 >>> "\texample \r\n" + chr(0) + chr(255)
2130 '\texample \r\n\x00\xff' # in 2.1
2131 '\011example \015\012\000\377' # in 2.0
2132
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002133- Functions are now compared and hashed by identity, not by value, since
2134 the func_code attribute is writable.
2135
Fred Drakefb9d7122001-02-01 20:00:40 +00002136- Weak references (PEP 205) have been added. This involves a few
2137 changes in the core, an extension module (_weakref), and a Python
2138 module (weakref). The weakref module is the public interface. It
2139 includes support for "explicit" weak references, proxy objects, and
2140 mappings with weakly held values.
2141
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002142- A 'continue' statement can now appear in a try block within the body
2143 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002144 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002145
Tim Petersd7b5e882001-01-25 03:36:26 +00002146Standard library
2147
Barry Warsaw30dbd142001-01-31 22:14:01 +00002148- mailbox.py now has a new class, PortableUnixMailbox which is
2149 identical to UnixMailbox but uses a more portable scheme for
2150 determining From_ separators. Also, the constructors for all the
2151 classes in this module have a new optional `factory' argument, which
2152 is a callable used when new message classes must be instantiated by
2153 the next() method.
2154
Tim Petersd7b5e882001-01-25 03:36:26 +00002155- random.py is now self-contained, and offers all the functionality of
2156 the now-deprecated whrandom.py. See the docs for details. random.py
2157 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002158 and restoring the internal state of the generator; and jumpahead(n),
2159 for quickly forcing the internal state to be the same as if n calls to
2160 random() had been made. The latter is particularly useful for multi-
2161 threaded programs, creating one instance of the random.Random() class for
2162 each thread, then using .jumpahead() to force each instance to use a
2163 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002164
Tim Peters0de88fc2001-02-01 04:59:18 +00002165- random.py's seed() function is new. For bit-for-bit compatibility with
2166 prior releases, use the whseed function instead. The new seed function
2167 addresses two problems: (1) The old function couldn't produce more than
2168 about 2**24 distinct internal states; the new one about 2**45 (the best
2169 that can be done in the Wichmann-Hill generator). (2) The old function
2170 sometimes produced identical internal states when passed distinct
2171 integers, and there was no simple way to predict when that would happen;
2172 the new one guarantees to produce distinct internal states for all
2173 arguments in [0, 27814431486576L).
2174
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002175- The socket module now supports raw packets on Linux. The socket
2176 family is AF_PACKET.
2177
Tim Peters9ea17ac2001-02-02 05:57:15 +00002178- test_capi.py is a start at running tests of the Python C API. The tests
2179 are implemented by the new Modules/_testmodule.c.
2180
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002181- A new extension module, _symtable, provides provisional access to the
2182 internal symbol table used by the Python compiler. A higher-level
2183 interface will be added on top of _symtable in a future release.
2184
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002185- Removed the obsolete soundex module.
2186
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002187- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2188 the isSameNode method; NamedNodeMap the get method.
2189
2190- xml.sax.expatreader supports the lexical handler property; it
2191 generates comment, startCDATA, and endCDATA events.
2192
Tim Petersee826f82001-01-31 19:39:44 +00002193Windows changes
2194
2195- Build procedure: the zlib project is built in a different way that
2196 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002197 the zlib binary used. See PCbuild\readme.txt for details. Your old
2198 zlib-related directories can be deleted; you'll need to download fresh
2199 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002200
Tim Peters9ea17ac2001-02-02 05:57:15 +00002201- Build: New subproject _test for the benefit of test_capi.py (see above).
2202
Tim Petersb16c56f2001-02-02 21:24:51 +00002203- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2204 interface to some Python compiler internals).
2205
2206- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002207 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002208
Tim Petersa3a3a032000-11-30 05:22:44 +00002209What's New in Python 2.1 alpha 1?
2210=================================
2211
2212Core language, builtins, and interpreter
2213
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002214- There is a new Unicode companion to the PyObject_Str() API
2215 called PyObject_Unicode(). It behaves in the same way as the
2216 former, but assures that the returned value is an Unicode object
2217 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002218
Guido van Rossumf98eda02001-01-17 15:54:45 +00002219- The comparison operators support "rich comparison overloading" (PEP
2220 207). C extension types can provide a rich comparison function in
2221 the new tp_richcompare slot in the type object. The cmp() function
2222 and the C function PyObject_Compare() first try the new rich
2223 comparison operators before trying the old 3-way comparison. There
2224 is also a new C API PyObject_RichCompare() (which also falls back on
2225 the old 3-way comparison, but does not constrain the outcome of the
2226 rich comparison to a Boolean result).
2227
2228 The rich comparison function takes two objects (at least one of
2229 which is guaranteed to have the type that provided the function) and
2230 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2231 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2232 object, which may be NotImplemented (in which case the tp_compare
2233 slot function is used as a fallback, if defined).
2234
2235 Classes can overload individual comparison operators by defining one
2236 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002237 __ge__. There are no explicit "reflected argument" versions of
2238 these; instead, __lt__ and __gt__ are each other's reflection,
2239 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2240 reflection (similar at the C level). No other implications are
2241 made; in particular, Python does not assume that == is the Boolean
2242 inverse of !=, or that < is the Boolean inverse of >=. This makes
2243 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002244
2245 Classes or types that want to implement (in)equality tests but not
2246 the ordering operators (i.e. unordered types) should implement ==
2247 and !=, and raise an error for the ordering operators.
2248
Guido van Rossuma88479f2001-01-18 14:28:08 +00002249 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002250 Boolean; e.g. a matrix type might want to return a matrix of bits
2251 for A < B, giving elementwise comparisons. Such types should ensure
2252 that any interpretation of their value in a Boolean context raises
2253 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2254 at the C level) to always raise an exception.
2255
Guido van Rossuma88479f2001-01-18 14:28:08 +00002256- Complex numbers use rich comparisons to define == and != but raise
2257 an exception for <, <=, > and >=. Unfortunately, this also means
2258 that cmp() of two complex numbers raises an exception when the two
2259 numbers differ. Since it is not mathematically meaningful to compare
2260 complex numbers except for equality, I hope that this doesn't break
2261 too much code.
2262
Tim Peters3389f192001-02-18 08:48:49 +00002263- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002264 not defined by the language, other than that it's arbitrary but
2265 consistent (see the Reference Manual). An implementation detail changed
2266 in 2.1a1 such that None now compares less than any other object. Code
2267 relying on this new behavior (like code that relied on the previous
2268 behavior) does so at its own risk.
2269
Barry Warsaw573b5412001-01-15 20:43:18 +00002270- Functions and methods now support getting and setting arbitrarily
2271 named attributes (PEP 232). Functions have a new __dict__
2272 (a.k.a. func_dict) which hold the function attributes. Methods get
2273 and set attributes on their underlying im_func. It is a TypeError
2274 to set an attribute on a bound method.
2275
Guido van Rossum051e3352001-01-15 19:11:10 +00002276- The xrange() object implementation has been improved so that
2277 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2278 limitation that in this case len(xrange(sys.maxint)) can't be
2279 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2280 work fine as long as the index i doesn't actually reach 2**31.
2281 (Python uses regular ints for sequence and string indices; fixing
2282 that is much more work.)
2283
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002284- Two changes to from...import:
2285
Guido van Rossumba381232001-02-03 15:06:40 +00002286 1) "from M import X" now works even if (after loading module M)
2287 sys.modules['M'] is not a real module; it's basically a getattr()
2288 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002289
2290 2) "from M import *" now looks for M.__all__ to decide which names to
2291 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2292 filters out names starting with '_' as before. Whether or not
2293 __all__ exists, there's no restriction on the type of M.
2294
Guido van Rossumf61f1662001-01-10 20:13:55 +00002295- File objects have a new method, xreadlines(). This is the fastest
2296 way to iterate over all lines in a file:
2297
2298 for line in file.xreadlines():
2299 ...do something to line...
2300
2301 See the xreadlines module (mentioned below) for how to do this for
2302 other file-like objects.
2303
2304- Even if you don't use file.xreadlines(), you may expect a speedup on
2305 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002306 quite a bit in platform-specific ways: on systems (like Linux) that
2307 support flockfile(), getc_unlocked(), and funlockfile(), those are
2308 used by default. On systems (like Windows) without getc_unlocked(),
2309 a complicated (but still thread-safe) method using fgets() is used by
2310 default.
2311
Tim Petersd52269b2001-01-25 06:23:18 +00002312 You can force use of the fgets() method by #define'ing
2313 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002314 getc_unlocked()).
2315
Tim Petersd52269b2001-01-25 06:23:18 +00002316 You can force fgets() not to be used by #define'ing
2317 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002318 test_bufio.py fails -- and let us know if it does!).
2319
2320- In addition, the fileinput module, while still slower than the other
2321 methods on most platforms, has been sped up too, by using
2322 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002323
2324- Support for run-time warnings has been added, including a new
2325 command line option (-W) to specify the disposition of warnings.
2326 See the description of the warnings module below.
2327
2328- Extensive changes have been made to the coercion code. This mostly
2329 affects extension modules (which can now implement mixed-type
2330 numerical operators without having to use coercion), but
2331 occasionally, in boundary cases the coercion semantics have changed
2332 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002333 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002334 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002335 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002336
Guido van Rossumf98eda02001-01-17 15:54:45 +00002337- In connection with the coercion changes, a new built-in singleton
2338 object, NotImplemented is defined. This can be returned for
2339 operations that wish to indicate they are not implemented for a
2340 particular combination of arguments. From C, this is
2341 Py_NotImplemented.
2342
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002343- The interpreter accepts now bytecode files on the command line even
2344 if they do not have a .pyc or .pyo extension. On Linux, after executing
2345
Martin v. Löwise214baa2001-02-04 22:37:56 +00002346import imp,sys,string
2347magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2348reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2349open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002350
2351 any byte code file can be used as an executable (i.e. as an argument
2352 to execve(2)).
2353
Tim Peters9940b802000-12-01 07:59:35 +00002354- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002355 character. In 1.6 and earlier, they never produced a sign,
2356 and raised an error if the value of the long was too large
2357 to fit in a Python int. In 2.0, they produced a sign if and
2358 only if too large to fit in an int. This was inconsistent
2359 across platforms (because the size of an int varies across
2360 platforms), and inconsistent with hex() and oct(). Example:
2361
2362 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002363 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002364 'ffffffbe' # in 2.0 and before, on 32-bit machines
2365 >>> hex(-0x42L)
2366 '-0x42L' # in all versions of Python
2367
Tim Peters9940b802000-12-01 07:59:35 +00002368 The behavior of %d formats for negative Python longs remains
2369 the same as in 2.0 (although in 1.6 and before, they raised
2370 an error if the long didn't fit in a Python int).
2371
2372 %u formats don't make sense for Python longs, but are allowed
2373 and treated the same as %d in 2.1. In 2.0, a negative long
2374 formatted via %u produced a sign if and only if too large to
2375 fit in an int. In 1.6 and earlier, a negative long formatted
2376 via %u raised an error if it was too big to fit in an int.
2377
Guido van Rossum3661d392000-12-12 22:10:31 +00002378- Dictionary objects have an odd new method, popitem(). This removes
2379 an arbitrary item from the dictionary and returns it (in the form of
2380 a (key, value) pair). This can be useful for algorithms that use a
2381 dictionary as a bag of "to do" items and repeatedly need to pick one
2382 item. Such algorithms normally end up running in quadratic time;
2383 using popitem() they can usually be made to run in linear time.
2384
Tim Peters36cdad12000-12-29 02:06:45 +00002385Standard library
2386
Thomas Woutersfe385252001-01-19 23:16:56 +00002387- In the time module, the time argument to the functions strftime,
2388 localtime, gmtime, asctime and ctime is now optional, defaulting to
2389 the current time (in the local timezone).
2390
Guido van Rossumda91f222001-01-15 16:36:08 +00002391- The ftplib module now defaults to passive mode, which is deemed a
2392 more useful default given that clients are often inside firewalls
2393 these days. Note that this could break if ftplib is used to connect
2394 to a *server* that is inside a firewall, from outside; this is
2395 expected to be a very rare situation. To fix that, you can call
2396 ftp.set_pasv(0).
2397
Martin v. Löwis10a27872001-01-13 09:54:41 +00002398- The module site now treats .pth files not only for path configuration,
2399 but also supports extensions to the initialization code: Lines starting
2400 with import are executed.
2401
Guido van Rossumf61f1662001-01-10 20:13:55 +00002402- There's a new module, warnings, which implements a mechanism for
2403 issuing and filtering warnings. There are some new built-in
2404 exceptions that serve as warning categories, and a new command line
2405 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2406 turns warnings into errors). warnings.warn(message[, category])
2407 issues a warning message; this can also be called from C as
2408 PyErr_Warn(category, message).
2409
2410- A new module xreadlines was added. This exports a single factory
2411 function, xreadlines(). The intention is that this code is the
2412 absolutely fastest way to iterate over all lines in an open
2413 file(-like) object:
2414
2415 import xreadlines
2416 for line in xreadlines.xreadlines(file):
2417 ...do something to line...
2418
2419 This is equivalent to the previous the speed record holder using
2420 file.readlines(sizehint). Note that if file is a real file object
2421 (as opposed to a file-like object), this is equivalent:
2422
2423 for line in file.xreadlines():
2424 ...do something to line...
2425
Tim Peters36cdad12000-12-29 02:06:45 +00002426- The bisect module has new functions bisect_left, insort_left,
2427 bisect_right and insort_right. The old names bisect and insort
2428 are now aliases for bisect_right and insort_right. XXX_right
2429 and XXX_left methods differ in what happens when the new element
2430 compares equal to one or more elements already in the list: the
2431 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002432 right. Code that doesn't care where equal elements end up should
2433 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002434
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002435- The new curses.panel module wraps the panel library that forms part
2436 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2437
Guido van Rossumf61f1662001-01-10 20:13:55 +00002438- The SocketServer module now sets the allow_reuse_address flag by
2439 default in the TCPServer class.
2440
2441- A new function, sys._getframe(), returns the stack frame pointer of
2442 the caller. This is intended only as a building block for
2443 higher-level mechanisms such as string interpolation.
2444
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002445- The pyexpat module supports a number of new handlers, which are
2446 available only in expat 1.2. If invocation of a callback fails, it
2447 will report an additional frame in the traceback. Parser objects
2448 participate now in garbage collection. If expat reports an unknown
2449 encoding, pyexpat will try to use a Python codec; that works only
2450 for single-byte charsets. The parser type objects is exposed as
2451 XMLParserObject.
2452
2453- xml.dom now offers standard definitions for symbolic node type and
2454 exception code constants, and a hierarchy of DOM exceptions. minidom
2455 was adjusted to use them.
2456
2457- The conformance of xml.dom.minidom to the DOM specification was
2458 improved. It detects a number of additional error cases; the
2459 previous/next relationship works even when the tree is modified;
2460 Node supports the normalize() method; NamedNodeMap, DocumentType and
2461 DOMImplementation classes were added; Element supports the
2462 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2463 method.
2464
Guido van Rossumf61f1662001-01-10 20:13:55 +00002465Build issues
2466
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002467- For Unix (and Unix-compatible) builds, configuration and building of
2468 extension modules is now greatly automated. Rather than having to
2469 edit the Modules/Setup file to indicate which modules should be
2470 built and where their include files and libraries are, a
2471 distutils-based setup.py script now takes care of building most
2472 extension modules. All extension modules built this way are built
2473 as shared libraries. Only a few modules that must be linked
2474 statically are still listed in the Setup file; you won't need to
2475 edit their configuration.
2476
2477- Python should now build out of the box on Cygwin. If it doesn't,
2478 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002479
2480- Python now always uses its own (renamed) implementation of getopt()
2481 -- there's too much variation among C library getopt()
2482 implementations.
2483
2484- C++ compilers are better supported; the CXX macro is always set to a
2485 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002486
Tim Petersd92dfe02000-12-12 01:18:41 +00002487Windows changes
2488
2489- select module: By default under Windows, a select() call
2490 can specify no more than 64 sockets. Python now boosts
2491 this Microsoft default to 512. If you need even more than
2492 that, see the MS docs (you'll need to #define FD_SETSIZE
2493 and recompile Python from source).
2494
Guido van Rossumf61f1662001-01-10 20:13:55 +00002495- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2496 subdirectory is no more!
2497
Tim Petersa3a3a032000-11-30 05:22:44 +00002498
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002499What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002500=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002501
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002502Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002503changes are in the file HISTORY. If you are making the jump directly
2504from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2505HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002506
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002507Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2508the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2509http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002510
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002511--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002512
2513======================================================================
2514
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002515What's new in 2.0 (since release candidate 1)?
2516==============================================
2517
2518Standard library
2519
2520- The copy_reg module was modified to clarify its intended use: to
2521 register pickle support for extension types, not for classes.
2522 pickle() will raise a TypeError if it is passed a class.
2523
2524- Fixed a bug in gettext's "normalize and expand" code that prevented
2525 it from finding an existing .mo file.
2526
2527- Restored support for HTTP/0.9 servers in httplib.
2528
Tim Peters989b7b92000-10-16 20:24:53 +00002529- The math module was changed to stop raising OverflowError in case of
2530 underflow, and return 0 instead in underflow cases. Whether Python
2531 used to raise OverflowError in case of underflow was platform-
2532 dependent (it did when the platform math library set errno to ERANGE
2533 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002534
2535- Fixed a bug in StringIO that occurred when the file position was not
2536 at the end of the file and write() was called with enough data to
2537 extend past the end of the file.
2538
2539- Fixed a bug that caused Tkinter error messages to get lost on
2540 Windows. The bug was fixed by replacing direct use of
2541 interp->result with Tcl_GetStringResult(interp).
2542
2543- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2544 redirect response.
2545
2546- Several changes were made to distutils: Some debugging code was
2547 removed from util. Fixed the installer used when an external zip
2548 program (like WinZip) is not found; the source code for this
2549 installer is in Misc/distutils. check_lib() was modified to behave
2550 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2551 test for whether installed modules are on sys.path was changed to
2552 use both normcase() and normpath().
2553
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002554- Several minor bugs were fixed in the xml package (the minidom,
2555 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002556
2557- The regression test driver (regrtest.py) behavior when invoked with
2558 -l changed: It now reports a count of objects that are recognized as
2559 garbage but not freed by the garbage collector.
2560
Tim Peters989b7b92000-10-16 20:24:53 +00002561- The regression test for the math module was changed to test
2562 exceptional behavior when the test is run in verbose mode. Python
2563 cannot yet guarantee consistent exception behavior across platforms,
2564 so the exception part of test_math is run only in verbose mode, and
2565 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002566
2567Internals
2568
2569- PyOS_CheckStack() has been disabled on Win64, where it caused
2570 test_sre to fail.
2571
2572Build issues
2573
2574- Changed compiler flags, so that gcc is always invoked with -Wall and
2575 -Wstrict-prototypes. Users compiling Python with GCC should see
2576 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002577 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002578 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002579
Tim Petersa3a3a032000-11-30 05:22:44 +00002580- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002581
2582Tools and other miscellany
2583
2584- The compiler in Tools/compiler was updated to support the new
2585 language features introduced in 2.0: extended print statement, list
2586 comprehensions, and augmented assignments. The new compiler should
2587 also be backwards compatible with Python 1.5.2; the compiler will
2588 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002589 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002590
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002591What's new in 2.0 release candidate 1 (since beta 2)?
2592=====================================================
2593
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002594What is release candidate 1?
2595
2596We believe that release candidate 1 will fix all known bugs that we
2597intend to fix for the 2.0 final release. This release should be a bit
2598more stable than the previous betas. We would like to see even more
2599widespread testing before the final release, so we are producing this
2600release candidate. The final release will be exactly the same unless
2601any show-stopping (or brown bag) bugs are found by testers of the
2602release candidate.
2603
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002604All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002605to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002606
2607Core language, builtins, and interpreter
2608
2609- A bug that caused crashes when __coerce__ was used with augmented
2610 assignment, e.g. +=, was fixed.
2611
2612- Raise ZeroDivisionError when raising zero to a negative number,
2613 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2614 power operator and the result of math.pow(0.0, -2.0) will vary by
2615 platform. On Linux, it raises a ValueError.
2616
2617- A bug in Unicode string interpolation was fixed that occasionally
2618 caused errors with formats including "%%". For example, the
2619 following expression "%% %s" % u"abc" no longer raises a TypeError.
2620
2621- Compilation of deeply nested expressions raises MemoryError instead
2622 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2623
2624- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2625 rendering them useless. They are now written in binary mode again.
2626
2627Standard library
2628
2629- Keyword arguments are now accepted for most pattern and match object
2630 methods in SRE, the standard regular expression engine.
2631
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002632- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002633 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002634
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002635- Several bugs in the Unicode handling and error handling in _tkinter
2636 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002637
2638- Fix memory management errors in Merge() and Tkapp_Call() routines.
2639
2640- Several changes were made to cStringIO to make it compatible with
2641 the file-like object interface and with StringIO. If operations are
2642 performed on a closed object, an exception is raised. The truncate
2643 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002644 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002645
2646- There were many changes made to the linuxaudiodev module and its
2647 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002648 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002649
2650 Note that this module is named poorly, because it should work
2651 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002652 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002653
2654 The module now raises exceptions when errors occur instead of
2655 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2656 audio) and defines a getptr() method that calls the
2657 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2658
2659- The library_version attribute, introduced in an earlier beta, was
2660 removed because it can not be supported with early versions of the C
2661 readline library, which provides no way to determine the version at
2662 compile-time.
2663
2664- The binascii module is now enabled on Win64.
2665
Tim Peters46446d62000-10-09 21:19:31 +00002666- tokenize.py no longer suffers "recursion depth" errors when parsing
2667 programs with very long string literals.
2668
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002669Internals
2670
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002671- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002672 which is called when the interpreter starts up to determine where
2673 the standard library is installed. These vulnerabilities affect all
2674 previous versions of Python and can be exploited by setting very
2675 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2676 setuid Python script, although use of the wrapper in
2677 Misc/setuid-prog.c will eliminate the vulnerability.
2678
2679- Fixed garbage collection bugs in instance creation that were
2680 triggered when errors occurred during initialization. The solution,
2681 applied in cPickle and in PyInstance_New(), is to call
2682 PyObject_GC_Init() after the initialization of the object's
2683 container attributes is complete.
2684
2685- pyexpat adds definitions of PyModule_AddStringConstant and
2686 PyModule_AddObject if the Python version is less than 2.0, which
2687 provides compatibility with PyXML on Python 1.5.2.
2688
2689- If the platform has a bogus definition for LONG_BIT (the number of
2690 bits in a long), an error will be reported at compile time.
2691
2692- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2693 collection crashes and possibly other, unreported crashes.
2694
2695- Fixed a memory leak in _PyUnicode_Fini().
2696
2697Build issues
2698
2699- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002700 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002701 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002702
2703- The mmap.PAGESIZE constant is now initialized using sysconf when
2704 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2705
2706- The md5 file should now compile on all platforms.
2707
2708- The select module now compiles on platforms that do not define
2709 POLLRDNORM and related constants.
2710
2711- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002712 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002713
Jeremy Hylton10921202000-10-09 18:34:12 +00002714- BeOS: A number of changes were made to the build and installation
2715 process. ar-fake now operates on a directory of object files.
2716 dl_export.h is gone, and its macros now appear on the mwcc command
2717 line during build on PPC BeOS.
2718
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002719- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002720 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002721
2722- Cygwin: Support for shared libraries, Tkinter, and sockets.
2723
2724- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2725
2726Tools and other miscellany
2727
2728- Removed debugging prints from main used with freeze.
2729
Tim Peters46446d62000-10-09 21:19:31 +00002730- IDLE auto-indent no longer crashes when it encounters Unicode
2731 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002732
2733What's new in 2.0 beta 2 (since beta 1)?
2734========================================
2735
2736Core language, builtins, and interpreter
2737
Tim Peters482c0212000-09-26 06:33:09 +00002738- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002739 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002740
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002741- Add -h and -V command line options to print the usage message and
2742 Python version number and exit immediately.
2743
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002744- eval() and exec accept Unicode objects as code parameters.
2745
2746- getattr() and setattr() now also accept Unicode objects for the
2747 attribute name, which are converted to strings using the default
2748 encoding before lookup.
2749
2750- Multiplication on string and Unicode now does proper bounds
2751 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2752 string is too long."
2753
2754- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002755 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002756
Jeremy Hylton1b618592000-09-26 05:32:36 +00002757
2758Standard library and extensions
2759
Guido van Rossum5b08f132001-04-16 02:05:23 +00002760- socket module: the OpenSSL code now adds support for RAND_status()
2761 and EGD (Entropy Gathering Device).
2762
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002763- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002764 argument checking; it still takes no arguments.
2765
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002766- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002767
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002768- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002769
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002770- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002771
2772- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002773 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002774
2775- copy: Copy Unicode objects atomically.
2776
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002777- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002779- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002780
Fred Drake67233bc2000-09-26 16:40:27 +00002781- dbm: Add get() and setdefault() methods to dbm object. Add constant
2782 `library' to module that names the library used. Added doc strings
2783 and method names to error messages. Uses configure to determine
2784 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2785 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002786
2787- distutils: Update to version 0.9.3.
2788
2789- dl: Add several dl.RTLD_ constants.
2790
2791- fpectl: Now supported on FreeBSD.
2792
2793- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2794 found by the collector will be saved in gc.garbage. This is useful
2795 for debugging a program that creates reference cycles.
2796
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002797- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002798 of HTTP class. Do not close socket on zero-length response. Do not
2799 crash when server sends invalid content-length header.
2800
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002801- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002802
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002803- marshal: When reading a short, sign-extend on platforms where shorts
2804 are bigger than 16 bits. When reading a long, repair the unportable
2805 sign extension that was being done for 64-bit machines. (It assumed
2806 that signed right shift sign-extends.)
2807
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002808- operator: Add contains(), invert(), __invert__() as aliases for
2809 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002810
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002811- os: Add support for popen2() and popen3() on all platforms where
2812 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002813
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002814- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002815 clicking on a file in Explorer (or passing the file name to the
2816 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002817
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002818- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002819 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002820
2821- pickle: Now raises ValueError when an invalid pickle that contains
2822 a non-string repr where a string repr was expected. This behavior
2823 matches cPickle.
2824
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002825- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002826
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002827- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002828
2829- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002830 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002831 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002832
2833- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002834 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002835
2836- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002837 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002838 few cycles during startup since the first call to
2839 setdefaultencoding() will initialize the codec registry and the
2840 encodings package.
2841
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002842- socket: Support for size hint in readlines() method of object returned
2843 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002844
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002845- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002846 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002847 is followed by whitespace.
2848
Tim Petersa3a3a032000-11-30 05:22:44 +00002849- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002850
2851- struct: Check ranges for bytes and shorts.
2852
2853- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002854 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002855
2856- Tkinter: Image objects are now guaranteed to have unique ids. Set
2857 event.delta to zero if Tk version doesn't support mousewheel.
2858 Removed some debugging prints.
2859
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002860- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002861
Fred Drake67233bc2000-09-26 16:40:27 +00002862- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002863 which works around a bug in Norton AntiVirus 2000 that leads directly
2864 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002865
2866- xml: New version detection code allows PyXML to override standard
2867 XML package if PyXML version is greater than 0.6.1.
2868
Fred Drake64bb3802000-09-26 16:21:35 +00002869- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2870 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2871 tree only for nodes which are sufficiently interesting to a specific
2872 application. Does not provide the HTML-specific extensions. Still
2873 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874
Fred Drake64bb3802000-09-26 16:21:35 +00002875- xml.sax: SAX 2 support for Python, including all the handler
2876 interfaces needed to process XML 1.0 compliant XML. Some
2877 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878
Fred Drake64bb3802000-09-26 16:21:35 +00002879- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2880 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002881
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002882
Jeremy Hylton1b618592000-09-26 05:32:36 +00002883C API
2884
2885- Add three new convenience functions for module initialization --
2886 PyModule_AddObject(), PyModule_AddIntConstant(), and
2887 PyModule_AddStringConstant().
2888
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002889- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002890 removed and add #error to Python.h if NULL isn't defined after
2891 #include of stdio.h.
2892
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002893- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002894 backwards compatibility (at the source level) with old extensions.
2895
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002896- A wrapper API was added for signal() and sigaction(). Instead of
2897 either function, always use PyOS_getsig() to get a signal handler
2898 and PyOS_setsig() to set one. A new convenience typedef
2899 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002900
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002901- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902 internal data buffer and size of a string object -- or the default
2903 encoded version of a Unicode object.
2904
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002905- PyString_Size() and PyString_AsString() accept Unicode objects.
2906
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002907- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002908 exists). INT_MAX and LONG_MAX will always be defined, even if
2909 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002910
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002911- PyFloat_FromString takes a second argument, pend, that was
2912 effectively useless. It is now officially useless but preserved for
2913 backwards compatibility. If the pend argument is not NULL, *pend is
2914 set to NULL.
2915
2916- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2917 for the attribute name. See note on getattr() above.
2918
2919- A few bug fixes to argument processing for Unicode.
2920 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2921 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2922 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002923 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002924
2925- Py_BuildValue accepts B format (for bgen-generated code).
2926
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002927
Jeremy Hylton1b618592000-09-26 05:32:36 +00002928Internals
2929
2930- On Unix, fix code for finding Python installation directory so that
2931 it works when argv[0] is a relative path.
2932
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002933- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002934 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002935 rather than by generating a copy of the object.
2936
Tim Peters482c0212000-09-26 06:33:09 +00002937- Several of the internal Unicode tables are much smaller now, and
2938 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002939
Jeremy Hylton97693b02000-09-26 17:42:51 +00002940- In the garbage collector: Fixed bug in collection of tuples. Fixed
2941 bug that caused some instances to be removed from the container set
2942 while they were still live. Fixed parsing in gc.set_debug() for
2943 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002944
2945- Fixed refcount problem in instance deallocation that only occurred
2946 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2947
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002948- On Windows, getpythonregpath is now protected against null data in
2949 registry key.
2950
2951- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002952 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002953
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002954
Jeremy Hylton1b618592000-09-26 05:32:36 +00002955Build and platform-specific issues
2956
2957- Better support of GNU Pth via --with-pth configure option.
2958
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002959- Python/C API now properly exposed to dynamically-loaded extension
2960 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002961
2962- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2963 Don't define MS_SYNC to be zero when it is undefined. Added missing
2964 prototypes in posixmodule.c.
2965
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002966- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002967 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002968
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002969- Fix largefile support on older NetBSD systems and OpenBSD by adding
2970 define for TELL64.
2971
2972
2973Tools and other miscellany
2974
2975- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2976
2977- freeze: The modulefinder now works with 2.0 opcodes.
2978
Tim Petersa3a3a032000-11-30 05:22:44 +00002979- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002980 Move hackery of sys.argv until after the Tk instance has been
2981 created, which allows the application-specific Tkinter
2982 initialization to be executed if present; also pass an explicit
2983 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002984
Jeremy Hylton1b618592000-09-26 05:32:36 +00002985
2986What's new in 2.0 beta 1?
2987=========================
2988
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002989Source Incompatibilities
2990------------------------
2991
2992None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2993such as single-argument append(), connect() and bind(), and changes to
2994str(long) and repr(float).
2995
2996
2997Binary Incompatibilities
2998------------------------
2999
3000- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3001with Python 2.0; these extensions will have to be rebuilt for Python
30022.0.
3003
3004- On Windows, attempting to import a third party extension built for
3005Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3006can do about this. Check your PYTHONPATH environment variable!
3007
3008- Python bytecode files (*.pyc and *.pyo) are not compatible between
3009releases.
3010
3011
3012Overview of Changes Since 1.6
3013-----------------------------
3014
3015There are many new modules (including brand new XML support through
3016the xml package, and i18n support through the gettext module); a list
3017of all new modules is included below. Lots of bugs have been fixed.
3018
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003019The process for making major new changes to the language has changed
3020since Python 1.6. Enhancements must now be documented by a Python
3021Enhancement Proposal (PEP) before they can be accepted.
3022
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003023There are several important syntax enhancements, described in more
3024detail below:
3025
3026 - Augmented assignment, e.g. x += 1
3027
3028 - List comprehensions, e.g. [x**2 for x in range(10)]
3029
3030 - Extended import statement, e.g. import Module as Name
3031
3032 - Extended print statement, e.g. print >> file, "Hello"
3033
3034Other important changes:
3035
3036 - Optional collection of cyclical garbage
3037
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003038Python Enhancement Proposal (PEP)
3039---------------------------------
3040
3041PEP stands for Python Enhancement Proposal. A PEP is a design
3042document providing information to the Python community, or describing
3043a new feature for Python. The PEP should provide a concise technical
3044specification of the feature and a rationale for the feature.
3045
3046We intend PEPs to be the primary mechanisms for proposing new
3047features, for collecting community input on an issue, and for
3048documenting the design decisions that have gone into Python. The PEP
3049author is responsible for building consensus within the community and
3050documenting dissenting opinions.
3051
3052The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003053
3054Augmented Assignment
3055--------------------
3056
3057This must have been the most-requested feature of the past years!
3058Eleven new assignment operators were added:
3059
Guido van Rossume905e952000-09-05 12:42:46 +00003060 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003061
3062For example,
3063
3064 A += B
3065
3066is similar to
3067
3068 A = A + B
3069
3070except that A is evaluated only once (relevant when A is something
3071like dict[index].attr).
3072
3073However, if A is a mutable object, A may be modified in place. Thus,
3074if A is a number or a string, A += B has the same effect as A = A+B
3075(except A is only evaluated once); but if a is a list, A += B has the
3076same effect as A.extend(B)!
3077
3078Classes and built-in object types can override the new operators in
3079order to implement the in-place behavior; the not-in-place behavior is
3080used automatically as a fallback when an object doesn't implement the
3081in-place behavior. For classes, the method name is derived from the
3082method name for the corresponding not-in-place operator by inserting
3083an 'i' in front of the name, e.g. __iadd__ implements in-place
3084__add__.
3085
3086Augmented assignment was implemented by Thomas Wouters.
3087
3088
3089List Comprehensions
3090-------------------
3091
3092This is a flexible new notation for lists whose elements are computed
3093from another list (or lists). The simplest form is:
3094
3095 [<expression> for <variable> in <sequence>]
3096
Guido van Rossum56db0952000-09-06 23:34:25 +00003097For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003098This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003099
3100You can also add a condition:
3101
3102 [<expression> for <variable> in <sequence> if <condition>]
3103
3104For example, [w for w in words if w == w.lower()] would yield the list
3105of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003106than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003107
3108You can also have nested for loops and more than one 'if' clause. For
3109example, here's a function that flattens a sequence of sequences::
3110
3111 def flatten(seq):
3112 return [x for subseq in seq for x in subseq]
3113
3114 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3115
3116This prints
3117
3118 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3119
3120List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003121Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003122
3123
3124Extended Import Statement
3125-------------------------
3126
3127Many people have asked for a way to import a module under a different
3128name. This can be accomplished like this:
3129
3130 import foo
3131 bar = foo
3132 del foo
3133
3134but this common idiom gets old quickly. A simple extension of the
3135import statement now allows this to be written as follows:
3136
3137 import foo as bar
3138
3139There's also a variant for 'from ... import':
3140
3141 from foo import bar as spam
3142
3143This also works with packages; e.g. you can write this:
3144
3145 import test.regrtest as regrtest
3146
3147Note that 'as' is not a new keyword -- it is recognized only in this
3148context (this is only possible because the syntax for the import
3149statement doesn't involve expressions).
3150
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003151Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003152
3153
3154Extended Print Statement
3155------------------------
3156
3157Easily the most controversial new feature, this extension to the print
3158statement adds an option to make the output go to a different file
3159than the default sys.stdout.
3160
3161For example, to write an error message to sys.stderr, you can now
3162write:
3163
3164 print >> sys.stderr, "Error: bad dog!"
3165
3166As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003167evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003168
3169 print >> None, "Hello world"
3170
3171is equivalent to
3172
3173 print "Hello world"
3174
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003175Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003176
3177
3178Optional Collection of Cyclical Garbage
3179---------------------------------------
3180
3181Python is now equipped with a garbage collector that can hunt down
3182cyclical references between Python objects. It's no replacement for
3183reference counting; in fact, it depends on the reference counts being
3184correct, and decides that a set of objects belong to a cycle if all
3185their reference counts can be accounted for from their references to
3186each other. This devious scheme was first proposed by Eric Tiedemann,
3187and brought to implementation by Neil Schemenauer.
3188
3189There's a module "gc" that lets you control some parameters of the
3190garbage collection. There's also an option to the configure script
3191that lets you enable or disable the garbage collection. In 2.0b1,
3192it's on by default, so that we (hopefully) can collect decent user
3193experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003194performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003195off by default in the final 2.0 release.
3196
3197
3198Smaller Changes
3199---------------
3200
3201A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3202map(None, seq1, seq2, ...) when the sequences have the same length;
3203i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3204the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003205zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003206
3207sys.version_info is a tuple (major, minor, micro, level, serial).
3208
3209Dictionaries have an odd new method, setdefault(key, default).
3210dict.setdefault(key, default) returns dict[key] if it exists; if not,
3211it sets dict[key] to default and returns that value. Thus:
3212
3213 dict.setdefault(key, []).append(item)
3214
3215does the same work as this common idiom:
3216
3217 if not dict.has_key(key):
3218 dict[key] = []
3219 dict[key].append(item)
3220
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003221There are two new variants of SyntaxError that are raised for
3222indentation-related errors: IndentationError and TabError.
3223
3224Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3225escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003226
3227The limits on the size of expressions and file in Python source code
3228have been raised from 2**16 to 2**32. Previous versions of Python
3229were limited because the maximum argument size the Python VM accepted
3230was 2**16. This limited the size of object constructor expressions,
3231e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3232limit was raised thanks to a patch by Charles Waldman that effectively
3233fixes the problem. It is now much more likely that you will be
3234limited by available memory than by an arbitrary limit in Python.
3235
3236The interpreter's maximum recursion depth can be modified by Python
3237programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3238limit is the maximum number of recursive calls that can be made by
3239Python code. The limit exists to prevent infinite recursion from
3240overflowing the C stack and causing a core dump. The default value is
32411000. The maximum safe value for a particular platform can be found
3242by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003243
3244New Modules and Packages
3245------------------------
3246
3247atexit - for registering functions to be called when Python exits.
3248
3249imputil - Greg Stein's alternative API for writing custom import
3250hooks.
3251
3252pyexpat - an interface to the Expat XML parser, contributed by Paul
3253Prescod.
3254
3255xml - a new package with XML support code organized (so far) in three
3256subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3257would fill a volume. There's a special feature whereby a
3258user-installed package named _xmlplus overrides the standard
3259xmlpackage; this is intended to give the XML SIG a hook to distribute
3260backwards-compatible updates to the standard xml package.
3261
3262webbrowser - a platform-independent API to launch a web browser.
3263
3264
Guido van Rossume905e952000-09-05 12:42:46 +00003265Changed Modules
3266---------------
3267
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003268array -- new methods for array objects: count, extend, index, pop, and
3269remove
3270
3271binascii -- new functions b2a_hex and a2b_hex that convert between
3272binary data and its hex representation
3273
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003274calendar -- Many new functions that support features including control
3275over which day of the week is the first day, returning strings instead
3276of printing them. Also new symbolic constants for days of week,
3277e.g. MONDAY, ..., SUNDAY.
3278
3279cgi -- FieldStorage objects have a getvalue method that works like a
3280dictionary's get method and returns the value attribute of the object.
3281
3282ConfigParser -- The parser object has new methods has_option,
3283remove_section, remove_option, set, and write. They allow the module
3284to be used for writing config files as well as reading them.
3285
3286ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003287optionally support the RFC 959 REST command.
3288
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003289gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003290
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003291httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3292the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003293
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003294locale -- implement getdefaultlocale for Win32 and Macintosh
3295
3296marshal -- no longer dumps core when marshaling deeply nested or
3297recursive data structures
3298
3299os -- new functions isatty, seteuid, setegid, setreuid, setregid
3300
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003301os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3302support under Unix.
3303
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003304os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003305
3306os.path -- fix semantics of os.path.commonprefix
3307
3308smtplib -- support for sending very long messages
3309
3310socket -- new function getfqdn()
3311
3312readline -- new functions to read, write and truncate history files.
3313The readline section of the library reference manual contains an
3314example.
3315
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003316select -- add interface to poll system call
3317
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003318shutil -- new copyfileobj function
3319
3320SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3321HTTP server.
3322
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003323Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003324
3325urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003326e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003327
3328whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003329
3330
3331Obsolete Modules
3332----------------
3333
3334None. However note that 1.6 made a whole slew of modules obsolete:
3335stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3336poly, zmod, strop, util, whatsound.
3337
3338
3339Changed, New, Obsolete Tools
3340----------------------------
3341
Tim Peters8b092332000-09-05 20:15:25 +00003342None.
Guido van Rossume905e952000-09-05 12:42:46 +00003343
3344
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003345C-level Changes
3346---------------
3347
3348Several cleanup jobs were carried out throughout the source code.
3349
3350All C code was converted to ANSI C; we got rid of all uses of the
3351Py_PROTO() macro, which makes the header files a lot more readable.
3352
3353Most of the portability hacks were moved to a new header file,
3354pyport.h; several other new header files were added and some old
3355header files were removed, in an attempt to create a more rational set
3356of header files. (Few of these ever need to be included explicitly;
3357they are all included by Python.h.)
3358
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003359Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003360and Win64, especially for the new Intel Itanium processor. Mick also
3361added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003362
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003363The C APIs to return an object's size have been update to consistently
3364use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3365previous versions, the abstract interfaces used PyXXX_Length and the
3366concrete interfaces used PyXXX_Size. The old names,
3367e.g. PyObject_Length, are still available for backwards compatibility
3368at the API level, but are deprecated.
3369
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003370The PyOS_CheckStack function has been implemented on Windows by
3371Fredrik Lundh. It prevents Python from failing with a stack overflow
3372on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003373
3374The GC changes resulted in creation of two new slots on object,
3375tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003376the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003377
3378The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003379C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003380
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003381PyErr_Format has been updated to automatically calculate the size of
3382the buffer needed to hold the formatted result string. This change
3383prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003384
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003385New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003386
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003387PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3388that are the same as their non-Ex counterparts except they take an
3389extra flag argument that tells them to close the file when done.
3390
3391XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003392
Tim Peters8b092332000-09-05 20:15:25 +00003393
3394Windows Changes
3395---------------
3396
3397New popen2/popen3/peopen4 in os module (see Changed Modules above).
3398
3399os.popen is much more usable on Windows 95 and 98. See Microsoft
3400Knowledge Base article Q150956. The Win9x workaround described there
3401is implemented by the new w9xpopen.exe helper in the root of your
3402Python installation. Note that Python uses this internally; it is not
3403a standalone program.
3404
3405Administrator privileges are no longer required to install Python
3406on Windows NT or Windows 2000. If you have administrator privileges,
3407Python's registry info will be written under HKEY_LOCAL_MACHINE.
3408Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003409under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003410uses of Python, but will prevent some advanced uses from working
3411(for example, running a Python script as an NT service, or possibly
3412from CGI).
3413
3414[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3415installer; instead, it installs the needed Tcl/Tk files directly in the
3416Python directory. If you already have a Tcl/Tk installation, this
3417wastes some disk space (about 4 Megs) but avoids problems with
3418conflicting Tcl/Tk installations, and makes it much easier for Python
3419to ensure that Tcl/Tk can find all its files.
3420
3421[This was new in 1.6] The Windows installer now installs by default in
3422\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3423
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003424
3425Updates to the changes between 1.5.2 and 1.6
3426--------------------------------------------
3427
3428The 1.6 NEWS file can't be changed after the release is done, so here
3429is some late-breaking news:
3430
3431New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3432and changes to getlocale() and setlocale().
3433
3434The new module is now enabled per default.
3435
3436It is not true that the encodings codecs cannot be used for normal
3437strings: the string.encode() (which is also present on 8-bit strings
3438!) allows using them for 8-bit strings too, e.g. to convert files from
3439cp1252 (Windows) to latin-1 or vice-versa.
3440
3441Japanese codecs are available from Tamito KAJIYAMA:
3442http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3443
3444
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003445======================================================================