blob: 2d710677b5a01300020bc8d0fad3f6f9a7c19262 [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 Rossum9923ffe2002-06-04 19:52:53 +00009- Classes using __slots__ are now properly garbage collected.
10 [SF bug 519621]
11
12- Tightened the __slots__ rules: a slot name must be a valid Python
13 identifier.
14
Guido van Rossum2e4e0262002-06-04 05:58:34 +000015- The constructor for the module type now requires a name argument and
16 takes an optional docstring argument. Previously, this constructor
17 ignored its arguments. As a consequence, deriving a class from a
18 module (not from the module type) is now illegal; previously this
19 created an unnamed module, just like invoking the module type did.
20 [SF bug 563060]
21
Neal Norwitzd68f5172002-05-29 15:54:55 +000022- A new warning PendingDeprecationWarning was added to provide
23 direction on features which are in the process of being deprecated.
24 The warning will not be printed by default. To see the pending
25 deprecations, use -Walways::PendingDeprecationWarning::
26 as a command line option or warnings.filterwarnings() in code.
27
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000028- A new type object, 'basestring', is added. This is a common base type
Guido van Rossumcacfc072002-05-24 19:01:59 +000029 for 'str' and 'unicode', and can be used instead of
30 types.StringTypes, e.g. to test whether something is "a string":
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000031 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
Guido van Rossumcacfc072002-05-24 19:01:59 +000032 is an abstract base class and cannot be instantiated directly.
33
Fred Draked0ba6362002-05-02 21:28:26 +000034- Deprecated features of xrange objects have been removed as
35 promised. The start, stop, and step attributes and the tolist()
36 method no longer exist. xrange repetition and slicing have been
37 removed.
38
Guido van Rossum7dab2422002-04-26 19:40:56 +000039- New builtin function enumerate(x), from PEP 279. Example:
40 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
41 The argument can be an arbitrary iterable object.
42
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000043- The assert statement no longer tests __debug__ at runtime. This means
44 that assert statements cannot be disabled by assigning a false value
45 to __debug__.
46
Walter Dörwald068325e2002-04-15 13:36:47 +000047- A method zfill() was added to str and unicode, that fills a numeric
48 string to the left with zeros. For example,
49 "+123".zfill(6) -> "+00123".
50
Guido van Rossum862fe3c2002-04-15 12:36:47 +000051- Complex numbers supported divmod() and the // and % operators, but
52 these make no sense. Since this was documented, they're being
53 deprecated now.
54
Guido van Rossum26dd8302002-04-26 20:11:29 +000055- String and unicode methods lstrip(), rstrip() and strip() now take
56 an optional argument that specifies the characters to strip. For
57 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000058
Guido van Rossumc69343b2002-04-12 19:22:48 +000059- Added a new dict method pop(key). This removes and returns the
60 value corresponding to key. [SF patch #539949]
61
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000062- Changed new-style class instantiation so that when C's __new__
63 method returns something that's not a C instance, its __init__ is
64 not called. [SF bug #537450]
65
Guido van Rossum181e41a2002-04-06 00:23:25 +000066- Fixed super() to work correctly with class methods. [SF bug #535444]
67
Guido van Rossum47834462002-04-04 15:21:33 +000068- A new built-in type, bool, has been added, as well as built-in
69 names for its two values, True and False. Comparisons and sundry
70 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +000071 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +000072 is backward compatible.
73
Guido van Rossum95b62a62002-03-29 01:07:24 +000074- Fixed two bugs reported as SF #535905: under certain conditions,
75 deallocating a deeply nested structure could cause a segfault in the
76 garbage collector, due to interaction with the "trashcan" code;
77 access to the current frame during destruction of a local variable
78 could access a pointer to freed memory.
79
Neil Schemenauer9d50d132002-03-22 17:06:59 +000080- The optional object allocator has been enabled by default.
81
Guido van Rossum8c842552002-03-14 23:05:54 +000082- If you try to pickle an instance of a class that has __slots__ but
83 doesn't define or override __getstate__, a TypeError is now raised.
84 This is done by adding a bozo __getstate__ to the class that always
85 raises TypeError. (Before, this would appear to be pickled, but the
86 state of the slots would be lost.)
87
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000088- PyErr_Display will provide file and line information for all exceptions
89 that have an attribute print_file_and_line, not just SyntaxErrors.
90
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000091- The UTF-8 codec will now encode and decode Unicode surrogates
92 correctly and without raising exceptions for unpaired ones.
93
Neal Norwitz649b7592002-01-01 19:07:13 +000094- file.xreadlines() now raises a ValueError if the file is closed:
95 Previously, an xreadlines object was returned which would raise
96 a ValueError when the xreadlines.next() method was called.
97
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +000098- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +000099 An exception will now be raised if more than one argument is used.
100
Tim Petersaf8446f2001-12-21 21:36:50 +0000101Extension modules
102
Tim Peters81b92512002-04-29 01:37:32 +0000103- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000104 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000105 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000106
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000107- posix.killpg and posix.mknod have been added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000108
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000109- The locale module now exposes the C library's gettext interface.
110
Tim Petersfbf74f22002-03-14 19:06:01 +0000111- A security hole ("double free") was found in zlib-1.1.3, a popular
112 third party compression library used by some Python modules. The
113 hole was quickly plugged in zlib-1.1.4, and the Windows build of
114 Python now ships with zlib-1.1.4.
115
Martin v. Löwis688357e2002-04-08 21:28:20 +0000116- pwd, grp, and resource return enhanced tuples now, with symbolic
117 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000118
Martin v. Löwis99866332002-03-01 10:27:01 +0000119- array.array is now a type object. A new format character
120 'u' indicates Py_UNICODE arrays. For those, .tounicode and
121 .fromunicode methods are available. Arrays now support __iadd__
122 and __imul__.
123
Neal Norwitze790eae2002-01-01 21:14:12 +0000124- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000125 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
126 is called.
127
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000128- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
129 been added where available.
130
Tim Petersaf8446f2001-12-21 21:36:50 +0000131Library
132
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000133- getopt.gnu_getopt was added.
134
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000135- Stop using strings for exceptions. String objects used for
136 exceptions are now classes deriving from Exception. The objects
137 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
138 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000139
Walter Dörwald474458d2002-06-04 15:16:29 +0000140- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
141 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
142 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
143 big endian systems were added to the codecs module. The old names
144 BOM32_* and BOM64_* were off by a factor of 2.
145
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000146- added degree/radian conversion functions to the math module.
147
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000148- ftplib.retrlines() now tests for callback is None rather than testing
149 for False. Was causing an error when given a callback object which
150 was callable but also returned len() as zero. The change may
151 create new breakage if the caller relied on the undocumented behavior
152 and called with callback set to [] or some other False value not
153 identical to None.
154
Tim Peters46c04e12002-05-05 20:40:00 +0000155- random.gauss() uses a piece of hidden state used by nothing else,
156 and the .seed() and .whseed() methods failed to reset it. In other
157 words, setting the seed didn't completely determine the sequence of
158 results produced by random.gauss(). It does now. Programs repeatedly
159 mixing calls to a seed method with calls to gauss() may see different
160 results now.
161
Fred Drake7f781c92002-05-01 20:33:53 +0000162- The pickle.Pickler class grew a clear_memo() method to mimic that
163 provided by cPickle.Pickler.
164
Tim Peters81b92512002-04-29 01:37:32 +0000165- difflib's SequenceMatcher class now does a dynamic analysis of
166 which elements are so frequent as to constitute noise. For
167 comparing files as sequences of lines, this generally works better
168 than the IS_LINE_JUNK function, and function ndiff's linejunk
169 argument defaults to None now as a result. A happy benefit is
170 that SequenceMatcher may run much faster now when applied
171 to large files with many duplicate lines (for example, C program
172 text with lots of repeated "}" and "return NULL;" lines).
173
Guido van Rossum256705b2002-04-23 13:29:43 +0000174- New Text.dump() method in Tkinter module.
175
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000176- New distutils commands for building packagers were added to
177 support pkgtool on Solaris and swinstall on HP-UX.
178
179- distutils now has a new abstract binary packager base class
180 command/bdist_packager, which simplifies writing packagers.
181 This will hopefully provide the missing bits to encourage
182 people to submit more packagers, e.g. for Debian, FreeBSD
183 and other systems.
184
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000185- The UTF-16, -LE and -BE now raise a NotImplementedError
186 for all calls to .readline(). Previously, they used to just
187 produce garbage or fail with an encoding error -- UTF-16 is
188 a 2-byte encoding and the C lib's line reading APIs don't
189 work well with these.
190
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000191- compileall now supports quiet operation.
192
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000193- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000194 connections.
195
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000196- socket module: the SSL support was broken out of the main
197 _socket module C helper and placed into a new _ssl helper
198 which now gets imported by socket.py if available and working.
199
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000200- encodings package: added aliases for all supported IANA character
201 sets
202
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000203- ftplib: to safeguard the user's privacy, anonymous login will use
204 "anonymous@" as default password, rather than the real user and host
205 name.
206
Fred Drake36736122002-01-10 13:50:31 +0000207- webbrowser: tightened up the command passed to os.system() so that
208 arbitrary shell code can't be executed because a bogus URL was
209 passed in.
210
Tim Peters11bd9942002-02-01 00:52:29 +0000211- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000212 gettext.find an optional all argument. Translations will now fallback
213 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000214
Martin v. Löwis9668b932002-01-12 11:27:42 +0000215- distutils bdist commands now offer a --skip-build option.
216
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000217- warnings.warn now accepts a Warning instance as first argument.
218
Fred Drakefed7e852002-04-04 19:36:15 +0000219- The xml.sax.expatreader.ExpatParser class will no longer create
220 circular references by using itself as the locator that gets passed
221 to the content handler implementation. [SF bug #535474]
222
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000223- The email.Parser.Parser class now properly parses strings regardless
224 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
225 or CRLF). Also, the Header class's constructor default arguments
226 has changed slightly so that an explicit maxlinelen value is always
227 honored.
228
Tim Petersaf8446f2001-12-21 21:36:50 +0000229Tools/Demos
230
Marc-André Lemburg46260092002-04-04 16:17:11 +0000231- freeze.py now produces binaries which can import shared modules,
232 unlike before when this failed due to missing symbol exports in
233 the generated binary.
234
Tim Petersaf8446f2001-12-21 21:36:50 +0000235Build
236
Tim Peters639295f2002-04-21 07:30:30 +0000237- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
238 say how or when to configure it, or how to turn it off.
239
Martin v. Löwis1142de32002-03-29 16:28:31 +0000240- On Unix, a shared libpython2.3.so can be created with --enable-shared.
241
Tim Peters8deda702002-03-30 10:06:07 +0000242- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
243 preprocessor symbols were eliminated. The internal decisions they
244 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000245
Fred Drake7d28b732002-05-02 21:17:00 +0000246- The tools used to build the documentation now work under Cygwin as
247 well as Unix.
248
Tim Petersaf8446f2001-12-21 21:36:50 +0000249C API
250
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000251- Added new macro PySequence_ITEM(o, i) that directly calls
252 sq_item without rechecking that o is a sequence and without
253 adjusting for negative indices.
254
Fred Draked0ba6362002-05-02 21:28:26 +0000255- PyRange_New() now raises ValueError if the fourth argument is not 1.
256 This is part of the removal of deprecated features of the xrange
257 object.
258
Guido van Rossum517c7d42002-04-26 02:49:14 +0000259- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
260 coercion if both arguments have the same type but this type has the
261 CHECKTYPES flag set. This is to better support proxies.
262
Neil Schemenauer9344b142002-04-12 23:00:08 +0000263- The type of tp_free has been changed from "void (*)(PyObject *)" to
264 "void (*)(void *)".
265
266- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
267
Guido van Rossum0986d822002-04-08 01:38:42 +0000268- A type can now inherit its metatype from its base type. Previously,
269 when PyType_Ready() was called, if ob_type was found to be NULL, it
270 was always set to &PyType_Type; now it is set to base->ob_type,
271 where base is tp_base, defaulting to &PyObject_Type.
272
273- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
274
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000275- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000276
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000277- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000278 without going through the buffer API.
279
Martin v. Löwis7198a522002-01-01 19:59:11 +0000280- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
281
Tim Peters10a3bb52001-12-25 19:07:38 +0000282- An old #define of ANY as void has been removed from pyport.h. This
283 hasn't been used since Python's pre-ANSI days, and the #define has
284 been marked as obsolete since then. SF bug 495548 says it created
285 conflicts with other packages, so keeping it around wasn't harmless.
286
Tim Petersaf8446f2001-12-21 21:36:50 +0000287- Because Python's magic number scheme broke on January 1st, we decided
288 to stop Python development. Thanks for all the fish!
289
Tim Petersfb05db22002-03-11 00:24:00 +0000290- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000291 scheme to a new one. See Python/import.c for details.
292
Tim Petersaf8446f2001-12-21 21:36:50 +0000293New platforms
294
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000295- GNU/Hurd is now supported.
296
Tim Petersaf8446f2001-12-21 21:36:50 +0000297Tests
298
299Windows
300
Tim Peters08e72952002-04-16 20:48:01 +0000301- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
302 of that has been fixed in the installer (disabled Wise's "delete in-
303 use files" uninstall option).
304
Guido van Rossum181e41a2002-04-06 00:23:25 +0000305- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
306
Tim Peters33187922002-04-04 20:02:04 +0000307- The installer now installs Start menu shortcuts under (the local
308 equivalent of) "All Users" when doing an Admin install.
309
Tim Petersfb05db22002-03-11 00:24:00 +0000310- file.truncate([newsize]) now works on Windows for all newsize values.
311 It used to fail if newsize didn't fit in 32 bits, reflecting a
312 limitation of MS _chsize (which is no longer used).
313
Tim Petersab034fa2002-02-01 11:27:43 +0000314- os.waitpid() is now implemented for Windows, and can be used to block
315 until a specified process exits. This is similar to, but not exactly
316 the same as, os.waitpid() on POSIX systems. If you're waiting for
317 a specific process whose pid was obtained from one of the spawn()
318 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000319 See the docs for details. The docs were changed to clarify that
320 spawn functions return, and waitpid requires, a process handle on
321 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000322
Tim Peters11bd9942002-02-01 00:52:29 +0000323- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000324 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000325 to a nasty problem: before 2.3, if you got a temp file on Windows, it
326 got wrapped in an object whose close() method first closed the
327 underlying file, then deleted the file. This usually worked fine.
328 However, the spawn family of functions on Windows create (at a low C
329 level) the same set of open files in the spawned process Q as were
330 open in the spawning process P. If a temp file f was among them, then
331 doing f.close() in P first closed P's C-level file handle on f, but Q's
332 C-level file handle on f remained open, so the attempt in P to delete f
333 blew up with a "Permission denied" error (Windows doesn't allow
334 deleting open files). This was surprising, subtle, and difficult to
335 work around.
336
337- The os module now exports all the symbolic constants usable with the
338 low-level os.open() on Windows: the new constants in 2.3 are
339 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
340 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
341 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
342 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
343 (so specify both if you want both; note that neither is useful unless
344 specified with O_CREAT too).
345
Tim Petersaf8446f2001-12-21 21:36:50 +0000346Mac
347
348
Tim Peters909c0912001-12-14 23:16:18 +0000349What's New in Python 2.2 final?
350Release date: 21-Dec-2001
351===============================
352
353Type/class unification and new-style classes
354
Barry Warsaw52acb492001-12-21 20:04:22 +0000355- pickle.py, cPickle: allow pickling instances of new-style classes
356 with a custom metaclass.
357
Tim Peters909c0912001-12-14 23:16:18 +0000358Core and builtins
359
Barry Warsaw52acb492001-12-21 20:04:22 +0000360- weakref proxy object: when comparing, unwrap both arguments if both
361 are proxies.
362
Tim Peters909c0912001-12-14 23:16:18 +0000363Extension modules
364
Barry Warsaw52acb492001-12-21 20:04:22 +0000365- binascii.b2a_base64(): fix a potential buffer overrun when encoding
366 very short strings.
367
368- cPickle: the obscure "fast" mode was suspected of causing stack
369 overflows on the Mac. Hopefully fixed this by setting the recursion
370 limit much smaller. If the limit is too low (it only affects
371 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
372 when compiling cPickle.c (or in pyconfig.h).
373
Tim Peters909c0912001-12-14 23:16:18 +0000374Library
375
Barry Warsaw52acb492001-12-21 20:04:22 +0000376- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
377 close or delete time).
378
379- rfc822.py: fixed a bug where the address '<>' was converted to None
380 instead of an empty string (also fixes the email.Utils module).
381
382- xmlrpclib.py: version 1.0.0; uses precision for doubles.
383
384- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000385 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000386
Tim Peters909c0912001-12-14 23:16:18 +0000387Tools/Demos
388
389Build
390
391C API
392
393New platforms
394
395Tests
396
397Windows
398
Barry Warsaw52acb492001-12-21 20:04:22 +0000399- distutils package: fixed broken Windows installers (bdist_wininst).
400
401- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
402 instances are deleted at process exit time.
403
404- socket.py: prevent mysterious warnings when socket instances are
405 deleted at process exit time.
406
407- posixmodule.c: fix a Windows crash with stat() of a filename ending
408 in backslash.
409
Tim Peters909c0912001-12-14 23:16:18 +0000410Mac
411
Barry Warsaw52acb492001-12-21 20:04:22 +0000412- The Carbon toolbox modules have been upgraded to Universal Headers
413 3.4, and experimental CoreGraphics and CarbonEvents modules have
414 been added. All only for framework-enabled MacOSX.
415
Tim Peters909c0912001-12-14 23:16:18 +0000416
Tim Peters6272dfd2001-12-13 19:34:00 +0000417What's New in Python 2.2c1?
418Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000419===========================
420
421Type/class unification and new-style classes
422
Barry Warsaw06557452001-12-14 20:47:12 +0000423- Guido's tutorial introduction to the new type/class features has
424 been extensively updated. See
425
426 http://www.python.org/2.2/descrintro.html
427
428 That remains the primary documentation in this area.
429
Guido van Rossum33bab012001-12-05 22:45:48 +0000430- Fixed a leak: instance variables declared with __slots__ were never
431 deleted!
432
Guido van Rossum4b800852001-12-03 00:54:52 +0000433- The "delete attribute" method of descriptor objects is called
434 __delete__, not __del__. In previous releases, it was mistakenly
435 called __del__, which created an unfortunate overloading condition
436 with finalizers. (The "get attribute" and "set attribute" methods
437 are still called __get__ and __set__, respectively.)
438
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000439- Some subtle issues with the super built-in were fixed:
440
441 (a) When super itself is subclassed, its __get__ method would still
442 return an instance of the base class (i.e., of super).
443
444 (b) super(C, C()).__class__ would return C rather than super. This
445 is confusing. To fix this, I decided to change the semantics of
446 super so that it only applies to code attributes, not to data
447 attributes. After all, overriding data attributes is not
448 supported anyway.
449
450 (c) The __get__ method didn't check whether the argument was an
451 instance of the type used in creation of the super instance.
452
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000453- Previously, hash() of an instance of a subclass of a mutable type
454 (list or dictionary) would return some value, rather than raising
455 TypeError. This has been fixed. Also, directly calling
456 dict.__hash__ and list.__hash__ now raises the same TypeError
457 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000458
Guido van Rossumd331cb52001-12-05 19:46:42 +0000459- New-style objects now support deleting their __dict__. This is for
460 all intents and purposes equivalent to assigning a brand new empty
461 dictionary, but saves space if the object is not used further.
462
Tim Petersb3c9af12001-11-17 00:21:57 +0000463Core and builtins
464
Tim Peters3caca232001-12-06 06:23:26 +0000465- -Qnew now works as documented in PEP 238: when -Qnew is passed on
466 the command line, all occurrences of "/" use true division instead
467 of classic division. See the PEP for details. Note that "all"
468 means all instances in library and 3rd-party modules, as well as in
469 your own code. As the PEP says, -Qnew is intended for use only in
470 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000471 Note that test_coercion.py in the standard Python test suite fails
472 under -Qnew; this is expected, and won't be repaired until true
473 division becomes the default (in the meantime, test_coercion is
474 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000475
Fred Drake6c01e252001-12-14 17:08:12 +0000476- complex() now only allows the first argument to be a string
477 argument, and raises TypeError if either the second arg is a string
478 or if the second arg is specified when the first is a string.
479
Tim Petersb3c9af12001-11-17 00:21:57 +0000480Extension modules
481
Martin v. Löwis560da622001-11-24 09:24:51 +0000482- gc.get_referents was renamed to gc.get_referrers.
483
Tim Petersb3c9af12001-11-17 00:21:57 +0000484Library
485
Tim Peters25059d32001-12-07 20:35:43 +0000486- Functions in the os.spawn() family now release the global interpreter
487 lock around calling the platform spawn. They should always have done
488 this, but did not before 2.2c1. Multithreaded programs calling
489 an os.spawn function with P_WAIT will no longer block all Python threads
490 until the spawned program completes. It's possible that some programs
491 relies on blocking, although more likely by accident than by design.
492
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000493- webbrowser defaults to netscape.exe on OS/2 now.
494
Martin v. Löwis652e1912001-11-25 14:50:56 +0000495- Tix.ResizeHandle exposes detach_widget, hide, and show.
496
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000497- The charset alias windows_1252 has been added.
498
Barry Warsaw06557452001-12-14 20:47:12 +0000499- types.StringTypes is a tuple containing the defined string types;
500 usually this will be (str, unicode), but if Python was compiled
501 without Unicode support it will be just (str,).
502
503- The pulldom and minidom modules were synchronized to PyXML.
504
Tim Petersb3c9af12001-11-17 00:21:57 +0000505Tools/Demos
506
Barry Warsaw06557452001-12-14 20:47:12 +0000507- A new script called Tools/scripts/google.py was added, which fires
508 off a search on Google.
509
Tim Petersb3c9af12001-11-17 00:21:57 +0000510Build
511
Barry Warsaw06557452001-12-14 20:47:12 +0000512- Note that release builds of Python should arrange to define the
513 preprocessor symbol NDEBUG on the command line (or equivalent).
514 In the 2.2 pre-release series we tried to define this by magic in
515 Python.h instead, but it proved to cause problems for extension
516 authors. The Unix, Windows and Mac builds now all define NDEBUG in
517 release builds via cmdline (or equivalent) instead. Ports to
518 other platforms should do likewise.
519
Jack Jansen1999ef42001-12-06 21:47:20 +0000520- It is no longer necessary to use --with-suffix when building on a
521 case-insensitive file system (such as Mac OS X HFS+). In the build
522 directory an extension is used, but not in the installed python.
523
Tim Petersb3c9af12001-11-17 00:21:57 +0000524C API
525
Tim Petersf582b822001-12-11 18:51:08 +0000526- New function PyDict_MergeFromSeq2() exposes the builtin dict
527 constructor's logic for updating a dictionary from an iterable object
528 producing key-value pairs.
529
Tim Peterscffed4b2001-11-29 03:26:37 +0000530- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000531 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000532 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
533 dump core in some bad cases. This has been repaired. As a result,
534 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
535 previously went unchallenged.
536
Tim Petersb3c9af12001-11-17 00:21:57 +0000537New platforms
538
539Tests
540
541Windows
542
543Mac
544
Jack Jansenffa260f2001-12-06 21:14:00 +0000545- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
546 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000547
Barry Warsaw06557452001-12-14 20:47:12 +0000548- Changed logic for finding python home in Mac OS X framework Pythons.
549 Now sys.executable points to the executable again, in stead of to
550 the shared library. The latter is used only for locating the python
551 home.
552
553
Tim Peters84362bc2001-10-19 17:55:30 +0000554What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000555Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000556===========================
557
558Type/class unification and new-style classes
559
Guido van Rossum3d27df02001-11-15 20:27:54 +0000560- Multiple inheritance mixing new-style and classic classes in the
561 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000562
563 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000564 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000565
566 The MRO (method resolution order) for each base class is respected
567 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000568 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000569 This needs to be documented.
570
Tim Petersa427a2b2001-10-29 22:25:45 +0000571- The new builtin dictionary() constructor, and dictionary type, have
572 been renamed to dict. This reflects a decade of common usage.
573
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000574- dict() now accepts an iterable object producing 2-sequences. For
575 example, dict(d.items()) == d for any dictionary d. The argument,
576 and the elements of the argument, can be any iterable objects.
577
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000578- New-style classes can now have a __del__ method, which is called
579 when the instance is deleted (just like for classic classes).
580
Guido van Rossum12d955c2001-10-26 14:56:06 +0000581- Assignment to object.__dict__ is now possible, for objects that are
582 instances of new-style classes that have a __dict__ (unless the base
583 class forbids it).
584
Guido van Rossumc8e56452001-10-22 00:43:43 +0000585- Methods of built-in types now properly check for keyword arguments
586 (formerly these were silently ignored). The only built-in methods
587 that take keyword arguments are __call__, __init__ and __new__.
588
Guido van Rossum86443212001-10-27 22:28:54 +0000589- The socket function has been converted to a type; see below.
590
Tim Peters84362bc2001-10-19 17:55:30 +0000591Core and builtins
592
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000593- Assignment to __debug__ raises SyntaxError at compile-time. This
594 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000595 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000596
Guido van Rossum12d955c2001-10-26 14:56:06 +0000597- Clarified the error messages for unsupported operands to an operator
598 (like 1 + '').
599
Tim Peters84362bc2001-10-19 17:55:30 +0000600Extension modules
601
Tim Peters5ebfd362001-11-13 23:11:19 +0000602- mmap has a new keyword argument, "access", allowing a uniform way for
603 both Windows and Unix users to create read-only, write-through and
604 copy-on-write memory mappings. This was previously possible only on
605 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000606 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000607 platforms. Thanks to Jay T Miller for repairing this!
608
Tim Peters169ded02001-11-03 19:57:21 +0000609- By default, the gc.garbage list now contains only those instances in
610 unreachable cycles that have __del__ methods; in 2.1 it contained all
611 instances in unreachable cycles. "Instances" here has been generalized
612 to include instances of both new-style and old-style classes.
613
Guido van Rossum12d955c2001-10-26 14:56:06 +0000614- The socket module defines a new method for socket objects,
615 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000616 send() until all data has been sent. Also, the socket function has
617 been converted to a subclassable type, like list and tuple (etc.)
618 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000619
620- Various bugfixes to the curses module. There is now a test suite
621 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000622
Guido van Rossum692adf12001-10-30 03:03:03 +0000623- binascii.b2a_base64 no longer places an arbitrary restriction of 57
624 bytes on its input.
625
Tim Peters84362bc2001-10-19 17:55:30 +0000626Library
627
Tim Peters5ebfd362001-11-13 23:11:19 +0000628- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000629 convenience function.
630
Tim Peters75335872001-11-03 19:35:43 +0000631- Symbolic group names in regular expressions must be unique. For
632 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
633 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000634 Python 2.2 detects this error at regexp compilation time;
635 previously, the error went undetected, and results were
636 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
637 pattern.subn() methods have been rewritten in C. Also, an
638 experimental function/method finditer() has been added, which works
639 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000640
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000641- Tix exposes more commands through the classes DirSelectBox,
642 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
643 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
644 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
645
Tim Peters98791af2001-10-23 01:59:54 +0000646- Traceback objects are now scanned by cyclic garbage collection, so
647 cycles created by casual use of sys.exc_info() no longer cause
648 permanent memory leaks (provided garbage collection is enabled).
649
Guido van Rossum49192142001-10-24 20:51:44 +0000650- os.extsep -- a new variable needed by the RISCOS support. It is the
651 separator used by extensions, and is '.' on all platforms except
652 RISCOS, where it is '/'. There is no need to use this variable
653 unless you have a masochistic desire to port your code to RISCOS.
654
Barry Warsaw012852b2001-11-16 16:17:27 +0000655- mimetypes.py has optional support for non-standard, but commonly
656 found types. guess_type() and guess_extension() now accept an
657 optional `strict' flag, defaulting to true, which controls whether
658 recognize non-standard types or not. A few non-standard types we
659 know about have been added. Also, when run as a script, there are
660 new -l and -e options.
661
662- statcache is now deprecated.
663
664- email.Utils.formatdate() now produces the preferred RFC 2822 style
665 dates with numeric timezones (it used to produce obsolete dates
666 hard coded to "GMT" timezone). An optional `localtime' flag is
667 added to produce dates in the local timezone, with daylight savings
668 time properly taken into account.
669
670- In pickle and cPickle, instead of masking errors in load() by
671 transforming them into SystemError, we let the original exception
672 propagate out. Also, implement support for __safe_for_unpickling__
673 in pickle, as it already was supported in cPickle.
674
Tim Peters84362bc2001-10-19 17:55:30 +0000675Tools/Demos
676
677Build
678
Barry Warsaw012852b2001-11-16 16:17:27 +0000679- The dbm module is built using libdb1 if available. The bsddb module
680 is built with libdb3 if available.
681
682- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
683
Tim Peters84362bc2001-10-19 17:55:30 +0000684C API
685
Tim Peters1fc240e2001-10-26 05:06:50 +0000686- New function PySequence_Fast_GET_SIZE() returns the size of a non-
687 NULL result from PySequence_Fast(), more quickly than calling
688 PySequence_Size().
689
Barry Warsaw012852b2001-11-16 16:17:27 +0000690- New argument unpacking function PyArg_UnpackTuple() added.
691
692- New functions PyObject_CallFunctionObjArgs() and
693 PyObject_CallMethodObjArgs() have been added to make it more
694 convenient and efficient to call functions and methods from C.
695
696- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
697 possible that this will propagate errors it didn't before.
698
699- New function PyObject_CheckReadBuffer(), which returns true if its
700 argument supports the single-segment readable buffer interface.
701
Tim Peters84362bc2001-10-19 17:55:30 +0000702New platforms
703
Guido van Rossum86443212001-10-27 22:28:54 +0000704- We've finally confirmed that this release builds on HP-UX 11.00,
705 *with* threads, and passes the test suite.
706
Tim Peters7a33d8b2001-11-05 02:51:07 +0000707- Thanks to a series of patches from Michael Muller, Python may build
708 again under OS/2 Visual Age C++.
709
Guido van Rossum49192142001-10-24 20:51:44 +0000710- Updated RISCOS port by Dietmar Schwertberger.
711
Tim Peters84362bc2001-10-19 17:55:30 +0000712Tests
713
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000714- Added a test script for the curses module. It isn't run automatically;
715 regrtest.py must be run with '-u curses' to enable it.
716
Tim Peters84362bc2001-10-19 17:55:30 +0000717Windows
718
Barry Warsaw012852b2001-11-16 16:17:27 +0000719Mac
720
721- PythonScript has been moved to unsupported and is slated to be
722 removed completely in the next release.
723
724- It should now be possible to build applets that work on both OS9 and
725 OSX.
726
727- The core is now linked with CoreServices not Carbon; as a side
728 result, default 8bit encoding on OSX is now ASCII.
729
730- Python should now build on OSX 10.1.1
731
Tim Peters84362bc2001-10-19 17:55:30 +0000732
Tim Petersabf925f2001-09-28 21:53:42 +0000733What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000734Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000735===========================
736
737Type/class unification and new-style classes
738
Guido van Rossum687ae002001-10-15 22:03:32 +0000739- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000740 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000741 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000742 remains: the __dict__ of a new-style class is a read-only proxy; you
743 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000744 __defined__ attribute of new-style types no longer exists, for lack
745 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000746 future a __cache__ may be resurrected with a similar function, if I
747 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000748
Tim Peters1c9ca872001-10-04 06:43:12 +0000749- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
750 always returned None, even when there was a class docstring).
751
752- doctest now finds and runs docstrings attached to new-style classes,
753 class methods, static methods, and properties.
754
Guido van Rossum9074ef62001-10-16 21:34:49 +0000755Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000756
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000757- A very subtle syntactical pitfall in list comprehensions was fixed.
758 For example: [a+b for a in 'abc', for b in 'def']. The comma in
759 this example is a mistake. Previously, this would silently let 'a'
760 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
761 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
762 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
763 Note that [a for a in <singleton>] is a convoluted way to say
764 [<singleton>] anyway, so it's not like any expressiveness is lost.
765
Guido van Rossum9074ef62001-10-16 21:34:49 +0000766- getattr(obj, name, default) now only catches AttributeError, as
767 documented, rather than returning the default value for all
768 exceptions (which could mask bugs in a __getattr__ hook, for
769 example).
770
Fred Drakecb7a6b52001-10-22 18:41:51 +0000771- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000772 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000773 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000774 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000775
Guido van Rossum1c486092001-10-19 02:05:35 +0000776- unicode(obj) now behaves more like str(obj), accepting arbitrary
777 objects, and calling a __unicode__ method if it exists.
778 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000779 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000780
Barry Warsawf6fb1712001-10-19 05:35:40 +0000781- isinstance() now allows any object as the first argument and a
782 class, a type or something with a __bases__ tuple attribute for the
783 second argument. The second argument may also be a tuple of a
784 class, type, or something with __bases__, in which case isinstance()
785 will return true if the first argument is an instance of any of the
786 things contained in the second argument tuple. E.g.
787
788 isinstance(x, (A, B))
789
790 returns true if x is an instance of A or B.
791
Guido van Rossum9074ef62001-10-16 21:34:49 +0000792Extension modules
793
794- thread.start_new_thread() now returns the thread ID (previously None).
795
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000796- binascii has now two quopri support functions, a2b_qp and b2a_qp.
797
Guido van Rossumc524d952001-10-19 01:31:59 +0000798- readline now supports setting the startup_hook and the
799 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000800
Guido van Rossumc524d952001-10-19 01:31:59 +0000801- os and posix supports chroot(), setgroups() and unsetenv() where
802 available. The stat(), fstat(), statvfs() and fstatvfs() functions
803 now return "pseudo-sequences" -- the various fields can now be
804 accessed as attributes (e.g. os.stat("/").st_mtime) but for
805 backwards compatibility they also behave as a fixed-length sequence.
806 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000807 attributes.
808
809- time: localtime(), gmtime() and strptime() now return a
810 pseudo-sequence similar to the os.stat() return value, with
811 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000812
Guido van Rossum9074ef62001-10-16 21:34:49 +0000813- Decompression objects in the zlib module now accept an optional
814 second parameter to decompress() that specifies the maximum amount
815 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000816
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000817- optional SSL support in the socket module now exports OpenSSL
818 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
819 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000820 automatically seed its PRNG. Also, the keyfile and certfile
821 arguments to socket.ssl() are now optional.
822
823- posixmodule (and by extension, the os module on POSIX platforms) now
824 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000825
Guido van Rossum9074ef62001-10-16 21:34:49 +0000826Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000827
Tim Peters7402f792001-10-02 03:53:41 +0000828- doctest now excludes functions and classes not defined by the module
829 being tested, thanks to Tim Hochberg.
830
Fred Drakecb7a6b52001-10-22 18:41:51 +0000831- HotShot, a new profiler implemented using a C-based callback, has
832 been added. This substantially reduces the overhead of profiling,
833 but it is still quite preliminary. Support modules and
834 documentation will be added in upcoming releases (before 2.2 final).
835
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000836- profile now produces correct output in situations where an exception
837 raised in Python is cleared by C code (e.g. hasattr()). This used
838 to cause wrong output, including spurious claims of recursive
839 functions and attribution of time spent to the wrong function.
840
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000841 The code and documentation for the derived OldProfile and HotProfile
842 profiling classes was removed. The code hasn't worked for years (if
843 you tried to use them, they raised exceptions). OldProfile
844 intended to reproduce the behavior of the profiler Python used more
845 than 7 years ago, and isn't interesting anymore. HotProfile intended
846 to provide a faster profiler (but producing less information), and
847 that's a worthy goal we intend to meet via a different approach (but
848 without losing information).
849
Tim Peterscce092d2001-10-09 05:31:56 +0000850- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000851 a much better system-specific calibration constant. The constant can
852 now be specified in an instance constructor, or as a Profile class or
853 instance variable, instead of by editing profile.py's source code.
854 Calibration must still be done manually (see the docs for the profile
855 module).
856
857 Note that Profile.calibrate() must be overriden by subclasses.
858 Improving the accuracy required exploiting detailed knowledge of
859 profiler internals; the earlier method abstracted away the details
860 and measured a simplified model instead, but consequently computed
861 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000862
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000863- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000864 which indicates whether output is intended for the header 'Q'
865 encoding.
866
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000867- The SocketServer.ThreadingMixIn class now closes the request after
868 finish_request() returns. (Not when it errors out though.)
869
Barry Warsawf6fb1712001-10-19 05:35:40 +0000870- The nntplib module's NNTP.body() method has grown a `file' argument
871 to allow saving the message body to a file.
872
873- The email package has added a class email.Parser.HeaderParser which
874 only parses headers and does not recurse into the message's body.
875 Also, the module/class MIMEAudio has been added for representing
876 audio data (contributed by Anthony Baxter).
877
878- ftplib should be able to handle files > 2GB.
879
880- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
881 ON, and OFF.
882
Fred Drakecb7a6b52001-10-22 18:41:51 +0000883- xml.dom.minidom NodeList objects now support the length attribute
884 and item() method as required by the DOM specifications.
885
Guido van Rossumed554f62001-10-02 23:15:37 +0000886Tools/Demos
887
888- Demo/dns was removed. It no longer serves any purpose; a package
889 derived from it is now maintained by Anthony Baxter, see
890 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000891
Barry Warsawf6fb1712001-10-19 05:35:40 +0000892- The freeze tool has been made more robust, and two new options have
893 been added: -X and -E.
894
Tim Petersabf925f2001-09-28 21:53:42 +0000895Build
896
Barry Warsawf6fb1712001-10-19 05:35:40 +0000897- configure will use CXX in LINKCC if CXX is used to build main() and
898 the system requires to link a C++ main using the C++ compiler.
899
Tim Petersabf925f2001-09-28 21:53:42 +0000900C API
901
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000902- The documentation for the tp_compare slot is updated to require that
903 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
904 not correct. This is not yet enforced but will be enforced in
905 Python 2.3; even later, we may use -2 to indicate errors and +2 for
906 "NotImplemented". Right now, -1 should be used for an error return.
907
Tim Petersd38b1c72001-09-30 05:09:37 +0000908- PyLong_AsLongLong() now accepts int (as well as long) arguments.
909 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
910 as long) arguments.
911
Guido van Rossum3c288632001-10-16 21:13:49 +0000912- PyThread_start_new_thread() now returns a long int giving the thread
913 ID, if one can be calculated; it returns -1 for error, 0 if no
914 thread ID is calculated (this is an incompatible change, but only
915 the thread module used this API). This code has only really been
916 tested on Linux and Windows; other platforms please beware (and
917 report any bugs or strange behavior).
918
Guido van Rossum1c486092001-10-19 02:05:35 +0000919- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
920 input.
921
Tim Petersabf925f2001-09-28 21:53:42 +0000922New platforms
923
924Tests
925
926Windows
927
Tim Peters04cf1d32001-10-09 22:39:40 +0000928- Installer: If you install IDLE, and don't disable file-extension
929 registration, a new "Edit with IDLE" context (right-click) menu entry
930 is created for .py and .pyw files.
931
Tim Peters1ce3cf72001-10-01 17:58:40 +0000932- The signal module now supports SIGBREAK on Windows, thanks to Steven
933 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
934 action remains to call Win32 ExitProcess(). This can be changed via
935 signal.signal(). For example:
936
937 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
938 # (SIGINT) behavior.
939 import signal
940 signal.signal(signal.SIGBREAK,
941 signal.default_int_handler)
942
943 try:
944 while 1:
945 pass
946 except KeyboardInterrupt:
947 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
948 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
949 # program without the possibility for any Python-level cleanup).
950 print "Clean exit"
951
Tim Petersabf925f2001-09-28 21:53:42 +0000952
Tim Petersb07352e2001-09-08 01:25:47 +0000953What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000954Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000955===========================
956
Guido van Rossum808eea72001-09-25 04:15:41 +0000957Type/class unification and new-style classes
958
959- pydoc and inspect are now aware of new-style classes;
960 e.g. help(list) at the interactive prompt now shows proper
961 documentation for all operations on list objects.
962
963- Applications using Jim Fulton's ExtensionClass module can now safely
964 be used with Python 2.2. In particular, Zope 2.4.1 now works with
965 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
966 examples also work again. It is hoped that Gtk and Boost also work
967 with 2.2a4 and beyond. (If you can confirm this, please write
968 webmaster@python.org; if there are still problems, please open a bug
969 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000970
Tim Peters66c1a522001-09-24 21:17:50 +0000971- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000972 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +0000973 in the constructed property object. fget, fset and fdel weren't
974 discoverable from Python in 2.2a3. __doc__ is new, and allows to
975 associate a docstring with a property.
976
Guido van Rossum808eea72001-09-25 04:15:41 +0000977- Comparison overloading is now more completely implemented. For
978 example, a str subclass instance can properly be compared to a str
979 instance, and it can properly overload comparison. Ditto for most
980 other built-in object types.
981
982- The repr() of new-style classes has changed; instead of <type
983 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
984 *except* for built-in types, which are still rendered as <type
985 'Foo'> (to avoid upsetting existing code that might parse or
986 otherwise rely on repr() of certain type objects).
987
988- The repr() of new-style objects is now always <Foo object at XXX>;
989 previously, it was sometimes <Foo instance at XXX>.
990
991- For new-style classes, what was previously called __getattr__ is now
992 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000993 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000994 one in classic classes is defined which is called only if regular
995 attribute access raises AttributeError; to catch *all* attribute
996 access, you can use __getattribute__ (for new-style classes). If
997 both are defined, __getattribute__ is called first, and if it raises
998 AttributeError, __getattr__ is called.
999
1000- The __class__ attribute of new-style objects can be assigned to.
1001 The new class must have the same C-level object layout as the old
1002 class.
1003
1004- The builtin file type can be subclassed now. In the usual pattern,
1005 "file" is the name of the builtin type, and file() is a new builtin
1006 constructor, with the same signature as the builtin open() function.
1007 file() is now the preferred way to open a file.
1008
1009- Previously, __new__ would only see sequential arguments passed to
1010 the type in a constructor call; __init__ would see both sequential
1011 and keyword arguments. This made no sense whatsoever any more, so
1012 now both __new__ and __init__ see all arguments.
1013
1014- Previously, hash() applied to an instance of a subclass of str or
1015 unicode always returned 0. This has been repaired.
1016
1017- Previously, an operation on an instance of a subclass of an
1018 immutable type (int, long, float, complex, tuple, str, unicode),
1019 where the subtype didn't override the operation (and so the
1020 operation was handled by the builtin type), could return that
1021 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001022 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001023 with the same value as s.
1024
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001025- Provisional support for pickling new-style objects has been added.
1026
Guido van Rossum808eea72001-09-25 04:15:41 +00001027Core
1028
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001029- file.writelines() now accepts any iterable object producing strings.
1030
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001031- PyUnicode_FromEncodedObject() now works very much like
1032 PyObject_Str(obj) in that it tries to use __str__/tp_str
1033 on the object if the object is not a string or buffer. This
1034 makes unicode() behave like str() when applied to non-string/buffer
1035 objects.
1036
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001037- PyFile_WriteObject now passes Unicode objects to the file's write
1038 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001039 of a print statement must support Unicode objects, i.e. they must
1040 at least convert them into ASCII strings.
1041
Guido van Rossum624c8af2001-09-18 15:21:04 +00001042- Thread scheduling on Solaris should be improved; it is no longer
1043 necessary to insert a small sleep at the start of a thread in order
1044 to let other runnable threads be scheduled.
1045
Tim Petersb07352e2001-09-08 01:25:47 +00001046Library
1047
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001048- StringIO.StringIO instances and cStringIO.StringIO instances support
1049 read character buffer compatible objects for their .write() methods.
1050 These objects are converted to strings and then handled as such
1051 by the instances.
1052
Barry Warsaw2f600732001-09-24 04:28:10 +00001053- The "email" package has been added. This is basically a port of the
1054 mimelib package <http://sf.net/projects/mimelib> with API changes
1055 and some implementations updated to use iterators and generators.
1056
Tim Peters8a9c2842001-09-22 21:30:22 +00001057- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1058 restores the ability of Tools/scripts/ndiff.py to start producing output
1059 before the entire comparison is complete.
1060
Barry Warsaw58b072d2001-09-22 04:44:21 +00001061- StringIO.StringIO instances and cStringIO.StringIO instances support
1062 iteration just like file objects (i.e. their .readline() method is
1063 called for each iteration until it returns an empty string).
1064
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001065- The codecs module has grown four new helper APIs to access
1066 builtin codecs: getencoder(), getdecoder(), getreader(),
1067 getwriter().
1068
Guido van Rossum624c8af2001-09-18 15:21:04 +00001069- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1070 simplifies writing XML RPC servers.
1071
Barry Warsaw647d5e82001-09-28 17:01:02 +00001072- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001073 after interpretation of symbolic links. On non-Unix systems, this
1074 is an alias for os.path.abspath().
1075
Tim Peters16a77ad2001-09-08 04:00:12 +00001076- operator.indexOf() (PySequence_Index() in the C API) now works with any
1077 iterable object.
1078
Guido van Rossum624c8af2001-09-18 15:21:04 +00001079- smtplib now supports various authentication and security features of
1080 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001081
Guido van Rossum624c8af2001-09-18 15:21:04 +00001082- hmac: a new module implementing keyed hashing for message
1083 authentication.
1084
1085- mimetypes now recognizes more extensions and file types. At the
1086 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001087
Guido van Rossum624c8af2001-09-18 15:21:04 +00001088- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001089 Python 2.2 bytecode generation. It has also been promoted from a
1090 Tool to a standard library package. (Tools/compiler still exists as
1091 a sample driver.)
1092
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001093Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001094
Tim Petersb07352e2001-09-08 01:25:47 +00001095Build
1096
Guido van Rossum624c8af2001-09-18 15:21:04 +00001097- Large file support (LFS) is now automatic when the platform supports
1098 it; no more manual configuration tweaks are needed. On Linux, at
1099 least, it's possible to have a system whose C library supports large
1100 files but whose kernel doesn't; in this case, large file support is
1101 still enabled but doesn't do you any good unless you upgrade your
1102 kernel or share your Python executable with another system whose
1103 kernel has large file support.
1104
1105- The configure script now supplies plausible defaults in a
1106 cross-compilation environment. This doesn't mean that the supplied
1107 values are always correct, or that cross-compilation now works
1108 flawlessly -- but it's a first step (and it shuts up most of
1109 autoconf's warnings about AC_TRY_RUN).
1110
1111- The Unix build is now a bit less chatty, courtesy of the parser
1112 generator. The build is completely silent (except for errors) when
1113 using "make -s", thanks to a -q option to setup.py.
1114
Tim Petersb07352e2001-09-08 01:25:47 +00001115C API
1116
Guido van Rossum624c8af2001-09-18 15:21:04 +00001117- The "structmember" API now supports some new flag bits to deny read
1118 and/or write access to attributes in restricted execution mode.
1119
Tim Petersb07352e2001-09-08 01:25:47 +00001120New platforms
1121
Guido van Rossum624c8af2001-09-18 15:21:04 +00001122- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1123 (http://familiar.handhelds.org).
1124
Tim Petersb07352e2001-09-08 01:25:47 +00001125Tests
1126
Tim Peters8a9c2842001-09-22 21:30:22 +00001127- The "classic" standard tests, which work by comparing stdout to
1128 an expected-output file under Lib/test/output/, no longer stop at
1129 the first mismatch. Instead the test is run to completion, and a
1130 variant of ndiff-style comparison is used to report all differences.
1131 This is much easier to understand than the previous style of reporting.
1132
1133- The unittest-based standard tests now use regrtest's test_main()
1134 convention, instead of running as a side-effect of merely being
1135 imported. This allows these tests to be run in more natural and
1136 flexible ways as unittests, outside the regrtest framework.
1137
1138- regrtest.py is much better integrated with unittest and doctest now,
1139 especially in regard to reporting errors.
1140
Tim Petersb07352e2001-09-08 01:25:47 +00001141Windows
1142
Guido van Rossum624c8af2001-09-18 15:21:04 +00001143- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001144 that support it (NTFS under Windows 2000). See "What's New in
1145 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001146
Tim Petersb07352e2001-09-08 01:25:47 +00001147
Tim Petersedc99312001-08-22 21:36:50 +00001148What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001149Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001150===========================
1151
1152Core
1153
Tim Peters9fffa3e2001-09-04 05:14:19 +00001154- Conversion of long to float now raises OverflowError if the long is too
1155 big to represent as a C double.
1156
Tim Peters32f453e2001-09-03 08:35:41 +00001157- The 3-argument builtin pow() no longer allows a third non-None argument
1158 if either of the first two arguments is a float, or if both are of
1159 integer types and the second argument is negative (in which latter case
1160 the arguments are converted to float, so this is really the same
1161 restriction).
1162
Tim Peters5d2b77c2001-09-03 05:47:38 +00001163- The builtin dir() now returns more information, and sometimes much
1164 more, generally naming all attributes of an object, and all attributes
1165 reachable from the object via its class, and from its class's base
1166 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1167 an empty list. In 2.2a3,
1168
1169 >>> dir([])
1170 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1171 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1172 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1173 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1174 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1175 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1176 'reverse', 'sort']
1177
1178 dir(module) continues to return only the module's attributes, though.
1179
Tim Petersbdee63f2001-09-02 03:40:59 +00001180- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001181 than raising OverflowError. This is a partial implementation of PEP
1182 237. You can use -Wdefault::OverflowWarning to enable a warning for
1183 this situation, and -Werror::OverflowWarning to revert to the old
1184 OverflowError exception.
1185
Guido van Rossum61c345f2001-09-04 03:26:15 +00001186- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001187 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001188 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1189 -Qold, meaning the / operator has its classic meaning and no
1190 warnings are issued. Using -Qwarn issues a run-time warning about
1191 all uses of classic division for int and long arguments; -Qwarnall
1192 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001193 (for use with fixdiv.py).
1194 [Note: the remainder of this paragraph (preserved below) became
1195 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1196 <obsolete>
1197 Using -Qnew is questionable; it turns on new division by default, but
1198 only in the __main__ module. You can usefully combine -Qwarn or
1199 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1200 warns about classic division everywhere else.
1201 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001202
Tim Petersbdee63f2001-09-02 03:40:59 +00001203- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001204 long, float, str, unicode, and tuple. (The types complex, list and
1205 dictionary can also be subclassed; this was introduced earlier.)
1206 Note that restrictions apply when subclassing immutable built-in
1207 types: you can only affect the value of the instance by overloading
1208 __new__. You can add mutable attributes, and the subclass instances
1209 will have a __dict__ attribute, but you cannot change the "value"
1210 (as implemented by the base class) of an immutable subclass instance
1211 once it is created.
1212
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001213- The dictionary constructor now takes an optional argument, a
1214 mapping-like object, and initializes the dictionary from its
1215 (key, value) pairs.
1216
Tim Petersbdee63f2001-09-02 03:40:59 +00001217- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001218 "cooperative super calls" in a multiple inheritance setting. For an
1219 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1220
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001221- A new built-in type, property, has been added. This enables the
1222 creation of "properties". These are attributes implemented by
1223 getter and setter functions (or only one of these for read-only or
1224 write-only attributes), without the need to override __getattr__.
1225 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001226
Tim Petersbdee63f2001-09-02 03:40:59 +00001227- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001228 liberalized, to allow leading zeroes. Examples of literals now
1229 legal that were SyntaxErrors before:
1230
1231 00.0 0e3 0100j 07.5 00000000000000000008.
1232
Tim Petersbdee63f2001-09-02 03:40:59 +00001233- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001234 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1235
Tim Petersedc99312001-08-22 21:36:50 +00001236Library
1237
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001238- telnetlib includes symbolic names for the options, and support for
1239 setting an option negotiation callback.
1240
Tim Petersa40c7932001-09-05 22:36:56 +00001241- The new C standard no longer requires that math libraries set errno to
1242 ERANGE on overflow. For platform libraries that exploit this new
1243 freedom, Python's overflow-checking was wholly broken. A new overflow-
1244 checking scheme attempts to repair that, but may not be reliable on all
1245 platforms (C doesn't seem to provide anything both useful and portable
1246 in this area anymore).
1247
Martin v. Löwis44f86962001-09-05 13:44:54 +00001248- Asynchronous timeout actions are available through the new class
1249 threading.Timer.
1250
Tim Peters78526162001-09-05 00:53:45 +00001251- math.log and math.log10 now return sensible results for even huge
1252 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1253
Tim Petersbdee63f2001-09-02 03:40:59 +00001254- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001255 currently held. See the docs for the imp module.
1256
Tim Petersbdee63f2001-09-02 03:40:59 +00001257- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001258 dumps containing ints written on platforms where Python ints are 8 bytes.
1259 When read on a box where Python ints are 4 bytes, such values are
1260 converted to Python longs.
1261
Tim Petersbdee63f2001-09-02 03:40:59 +00001262- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001263 code objects is no longer allowed. This plugs a security hole.
1264
Steve Purcell6091cd62001-09-06 16:05:17 +00001265- unittest.TestResult instances no longer store references to tracebacks
1266 generated by test failures. This prevents unexpected dangling references
1267 to objects that should be garbage collected between tests.
1268
Tim Petersedc99312001-08-22 21:36:50 +00001269Tools
1270
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001271- Tools/scripts/fixdiv.py has been added which can be used to fix
1272 division operators as per PEP 238.
1273
Tim Petersedc99312001-08-22 21:36:50 +00001274Build
1275
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001276- If you are an adventurous person using Mac OS X you may want to look at
1277 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1278 application, which can be used for experimenting with Carbon or Cocoa.
1279 Discussion of this on pythonmac-sig, please.
1280
Tim Peters7eea37e2001-09-04 22:08:56 +00001281C API
1282
1283- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001284
Tim Peters9fffa3e2001-09-04 05:14:19 +00001285- Note that PyLong_AsDouble can fail! This has always been true, but no
1286 callers checked for it. It's more likely to fail now, because overflow
1287 errors are properly detected now. The proper way to check:
1288
1289 double x = PyLong_AsDouble(some_long_object);
1290 if (x == -1.0 && PyErr_Occurred()) {
1291 /* The conversion failed. */
1292 }
1293
Tim Petersbdee63f2001-09-02 03:40:59 +00001294- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001295 compile but will not participate in GC. To upgrade an extension
1296 module:
1297
1298 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001299
Neil Schemenauer4042c692001-08-30 15:38:01 +00001300 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1301 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001302
Neil Schemenauer4042c692001-08-30 15:38:01 +00001303 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1304 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001305
Neil Schemenauer4042c692001-08-30 15:38:01 +00001306 - remove PyGC_HEAD_SIZE from object size calculations
1307
1308 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1309
Tim Petersbdee63f2001-09-02 03:40:59 +00001310- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001311 These can be used safely to construct string objects from a
1312 sprintf-style format string (similar to the format string supported
1313 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001314
Tim Petersedc99312001-08-22 21:36:50 +00001315New platforms
1316
Tim Petersb7da0902001-09-02 23:01:43 +00001317- Stephen Hansen contributed patches sufficient to get a clean compile
1318 under Borland C (Windows), but he reports problems running it and ran
1319 out of time to complete the port. Volunteers? Expect a MemoryError
1320 when importing the types module; this is probably shallow, and
1321 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001322
Tim Petersedc99312001-08-22 21:36:50 +00001323Tests
1324
1325Windows
1326
Tim Peters6e13a562001-09-06 00:32:15 +00001327- Large file support is now enabled on Win32 platforms as well as on
1328 Win64. This means that, for example, you can use f.tell() and f.seek()
1329 to manipulate files larger than 2 gigabytes (provided you have enough
1330 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001331 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1332 filesize limit, and large file support makes no difference there.
1333 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1334 NTFS has no practical limit on file size, and files of any size can be
1335 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001336
Tim Petersbdee63f2001-09-02 03:40:59 +00001337- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001338 points to command.com (patch from Brian Quinlan).
1339
Tim Petersedc99312001-08-22 21:36:50 +00001340
Tim Peters20f51a72001-07-21 02:31:40 +00001341What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001342Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001343===========================
1344
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001345Build
1346
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001347- Tim Peters developed a brand new Windows installer using Wise 8.1,
1348 generously donated to us by Wise Solutions.
1349
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001350- configure supports a new option --enable-unicode, with the values
1351 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1352 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001353
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001354- A new configure option --enable-framework builds a Mac OS X framework,
1355 which "make frameworkinstall" will install. This provides a starting
1356 point for more mac-like functionality, join pythonmac-sig@python.org
1357 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001358
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001359- The NeXT platform is no longer supported.
1360
1361- The `new' module is now statically linked.
1362
Tim Peters0afb6092001-08-15 06:06:44 +00001363Tools
1364
1365- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001366 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001367 the module docstring for details.
1368
Tim Peters20f51a72001-07-21 02:31:40 +00001369Tests
1370
Tim Peters5e824c32001-08-12 22:25:01 +00001371- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001372 platforms, allowing to give clearer test result output. regrtest
1373 also has optional --use/-u switch to run normally disabled tests
1374 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001375
Tim Peters20f51a72001-07-21 02:31:40 +00001376- Several new tests in the standard test suite, with special thanks to
1377 Nick Mathewson.
1378
1379Core
1380
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001381- The floor division operator // has been added as outlined in PEP
1382 238. The / operator still provides classic division (and will until
1383 Python 3.0) unless "from __future__ import division" is included, in
1384 which case the / operator will provide true division. The operator
1385 module provides truediv() and floordiv() functions. Augmented
1386 assignment variants are included, as are the equivalent overloadable
1387 methods and C API methods. See the PEP for a full discussion:
1388 <http://python.sf.net/peps/pep-0238.html>
1389
Tim Peters6cd6a822001-08-17 22:11:27 +00001390- Future statements are now effective in simulated interactive shells
1391 (like IDLE). This should "just work" by magic, but read Michael
1392 Hudson's "Future statements in simulated shells" PEP 264 for full
1393 details: <http://python.sf.net/peps/pep-0264.html>.
1394
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001395- The type/class unification (PEP 252-253) was integrated into the
1396 trunk and is not so tentative any more (the exact specification of
1397 some features is still tentative). A lot of work has done on fixing
1398 bugs and adding robustness and features (performance still has to
1399 come a long way).
1400
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001401- Warnings about a mismatch in the Python API during extension import
1402 now use the Python warning framework (which makes it possible to
1403 write filters for these warnings).
1404
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001405- A function's __dict__ (aka func_dict) will now always be a
1406 dictionary. It used to be possible to delete it or set it to None,
1407 but now both actions raise TypeErrors. It is still legal to set it
1408 to a dictionary object. Getting func.__dict__ before any attributes
1409 have been assigned now returns an empty dictionary instead of None.
1410
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001411- A new command line option, -E, was added which disables the use of
1412 all environment variables, or at least those that are specifically
1413 significant to Python. Usually those have a name starting with
1414 "PYTHON". This was used to fix a problem where the tests fail if
1415 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1416 older distribution.
1417
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001418Library
1419
Tim Peters5e824c32001-08-12 22:25:01 +00001420- New class Differ and new functions ndiff() and restore() in difflib.py.
1421 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001422 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001423
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001424- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1425 value using the minimal quoting required for the value; more
1426 reliable than using xml.sax.saxutils.escape() for attribute values.
1427
1428- Readline completion support for cmd.Cmd was added.
1429
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001430- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1431
1432- Added function threading.BoundedSemaphore()
1433
1434- Added Ka-Ping Yee's cgitb.py module.
1435
1436- The `new' module now exposes the CO_xxx flags.
1437
Martin v. Löwis560da622001-11-24 09:24:51 +00001438- The gc module offers the get_referents function.
1439
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001440New platforms
1441
1442C API
1443
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001444- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1445 which provide a cross-platform implementations for the
1446 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1447 the standard sprintf() and vsprintf() C lib APIs, these versions
1448 apply bounds checking on the used buffer which enhances protection
1449 against buffer overruns.
1450
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001451- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001452 and extensions using different Unicode widths is rendered next to
1453 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001454 will result in an ImportError. Unicode extensions writers must make
1455 sure to check the Unicode width compatibility in their extensions by
1456 using at least one of the mangled Unicode APIs in the extension.
1457
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001458- Two new flags METH_NOARGS and METH_O are available in method definition
1459 tables to simplify implementation of methods with no arguments and a
1460 single untyped argument. Calling such methods is more efficient than
1461 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1462 deprecated.
1463
Tim Petersc1731372001-08-04 08:12:36 +00001464Windows
1465
1466- "import module" now compiles module.pyw if it exists and nothing else
1467 relevant is found.
1468
Tim Peters20f51a72001-07-21 02:31:40 +00001469
Guido van Rossum55a78992001-07-17 17:22:32 +00001470What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001471Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001472===========================
1473
1474Core
Tim Petersa814db52001-05-14 07:05:58 +00001475
Tim Peters6d6c1a32001-08-02 04:15:00 +00001476- TENTATIVELY, a large amount of code implementing much of what's
1477 described in PEP 252 (Making Types Look More Like Classes) and PEP
1478 253 (Subtyping Built-in Types) was added. This will be released
1479 with Python 2.2a1. Documentation will be provided separately
1480 through http://www.python.org/2.2/. The purpose of releasing this
1481 with Python 2.2a1 is to test backwards compatibility. It is
1482 possible, though not likely, that a decision is made not to release
1483 this code as part of 2.2 final, if any serious backwards
1484 incompapatibilities are found during alpha testing that cannot be
1485 repaired.
1486
Guido van Rossum55a78992001-07-17 17:22:32 +00001487- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001488 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001489 more 'yield' statements. See PEP 255. Since this adds a new
1490 keyword to the language, this feature must be enabled by including a
1491 future statement: "from __future__ import generators" (see PEP 236).
1492 Generators will become a standard feature in a future release
1493 (probably 2.3). Without this future statement, 'yield' remains an
1494 ordinary identifier, but a warning is issued each time it is used.
1495 (These warnings currently don't conform to the warnings framework of
1496 PEP 230; we intend to fix this in 2.2a2.)
1497
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001498- The UTF-16 codec was modified to be more RFC compliant. It will now
1499 only remove BOM characters at the start of the string and then
1500 only if running in native mode (UTF-16-LE and -BE won't remove a
1501 leading BMO character).
1502
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001503- Strings now have a new method .decode() to complement the already
1504 existing .encode() method. These two methods provide direct access
1505 to the corresponding decoders and encoders of the registered codecs.
1506
1507 To enhance the usability of the .encode() method, the special
1508 casing of Unicode object return values was dropped (Unicode objects
1509 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001510
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001511 Both methods will now return whatever the codec in charge of the
1512 requested encoding returns as object, e.g. Unicode codecs will
1513 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1514 will return u"äöü"). This enables codec writer to create codecs
1515 for various simple to use conversions.
1516
1517 New codecs were added to demonstrate these new features (the .encode()
1518 and .decode() columns indicate the type of the returned objects):
1519
1520 Name | .encode() | .decode() | Description
1521 ----------------------------------------------------------------------
1522 uu | string | string | UU codec (e.g. for email)
1523 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001524 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001525 zlib | string | string | zlib compression
1526 hex | string | string | 2-byte hex codec
1527 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1528
Mark Hammond2a0af792001-05-14 03:09:36 +00001529- Some operating systems now support the concept of a default Unicode
1530 encoding for file system operations. Notably, Windows supports 'mbcs'
1531 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001532 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001533 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001534
1535 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001536 functions that return filenames (such as os.listdir()) to return Python
1537 string objects pre-encoded using the default file system encoding for
1538 the platform. As this encoding is likely to be different from Python's
1539 default encoding, converting this name to a Unicode object before passing
1540 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001541 would attempt to use its default encoding (generally ASCII) rather than
1542 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001543
Tim Petersa814db52001-05-14 07:05:58 +00001544 In general, this change simply removes surprises when working with
1545 Unicode and the file system, making these operations work as you expect,
1546 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001547 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001548
Tim Peters61dff2b2001-05-08 15:43:37 +00001549- Float (and complex) literals in source code were evaluated to full
1550 precision only when running from a .py file; the same code loaded from a
1551 .pyc (or .pyo) file could suffer numeric differences starting at about the
1552 12th significant decimal digit. For example, on a machine with IEEE-754
1553 floating arithmetic,
1554
1555 x = 9007199254740992.0
1556 print long(x)
1557
1558 printed 9007199254740992 if run directly from .py, but 9007199254740000
1559 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1560 str(float) instead of repr(float) when building code objects. marshal
1561 now uses repr(float) instead, which should reproduce floats to full
1562 machine precision (assuming the platform C float<->string I/O conversion
1563 functions are of good quality).
1564
1565 This may cause floating-point results to change in some cases, and
1566 usually for the better, but may also cause numerically unstable
1567 algorithms to break.
1568
Tim Peters2f228e72001-05-13 00:19:31 +00001569- The implementation of dicts suffers fewer collisions, which has speed
1570 benefits. However, the order in which dict entries appear in dict.keys(),
1571 dict.values() and dict.items() may differ from previous releases for a
1572 given dict. Nothing is defined about this order, so no program should
1573 rely on it. Nevertheless, it's easy to write test cases that rely on the
1574 order by accident, typically because of printing the str() or repr() of a
1575 dict to an "expected results" file. See Lib/test/test_support.py's new
1576 sortdict(dict) function for a simple way to display a dict in sorted
1577 order.
1578
Tim Peters7a3bfc32001-06-12 01:22:22 +00001579- Many other small changes to dicts were made, resulting in faster
1580 operation along the most common code paths.
1581
Guido van Rossum10315822001-05-01 20:54:30 +00001582- Dictionary objects now support the "in" operator: "x in dict" means
1583 the same as dict.has_key(x).
1584
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001585- The update() method of dictionaries now accepts generic mapping
1586 objects. Specifically the argument object must support the .keys()
1587 and __getitem__() methods. This allows you to say, for example,
1588 {}.update(UserDict())
1589
Guido van Rossum10315822001-05-01 20:54:30 +00001590- Iterators were added; this is a generalized way of providing values
1591 to a for loop. See PEP 234. There's a new built-in function iter()
1592 to return an iterator. There's a new protocol to get the next value
1593 from an iterator using the next() method (in Python) or the
1594 tp_iternext slot (in C). There's a new protocol to get iterators
1595 using the __iter__() method (in Python) or the tp_iter slot (in C).
1596 Iterating (i.e. a for loop) over a dictionary generates its keys.
1597 Iterating over a file generates its lines.
1598
Tim Petersf553f892001-05-01 20:45:31 +00001599- The following functions were generalized to work nicely with iterator
1600 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001601 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001602 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1603 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001604 join() method of strings
1605 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001606 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1607 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001608 right-hand side of assignment statements with multiple targets, such as
1609 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001610
Tim Petersd85e1022001-05-11 21:51:48 +00001611- Accessing module attributes is significantly faster (for example,
1612 random.random or os.path or yourPythonModule.yourAttribute).
1613
Tim Peterse63415e2001-05-08 04:38:29 +00001614- Comparing dictionary objects via == and != is faster, and now works even
1615 if the keys and values don't support comparisons other than ==.
1616
Tim Peters95bf9392001-05-10 08:32:44 +00001617- Comparing dictionaries in ways other than == and != is slower: there were
1618 insecurities in the dict comparison implementation that could cause Python
1619 to crash if the element comparison routines for the dict keys and/or
1620 values mutated the dicts. Making the code bulletproof slowed it down.
1621
Tim Peterseb28ef22001-06-02 05:27:19 +00001622- Collisions in dicts are resolved via a new approach, which can help
1623 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001624 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001625 faster now. Thanks to Christian Tismer for pointing out the cause and
1626 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001627
Tim Peters52e155e2001-06-16 05:42:57 +00001628- repr() is much faster for large containers (dict, list, tuple).
1629
1630
Tim Petersa814db52001-05-14 07:05:58 +00001631Library
1632
Fred Drake960fdf92001-07-20 18:38:26 +00001633- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1634 were added to the string module. These a locale-indenpendent
1635 constants, unlike letters, lowercase, and uppercase. These are now
1636 use in appropriate locations in the standard library.
1637
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001638- The flags used in dlopen calls can now be configured using
1639 sys.setdlopenflags and queried using sys.getdlopenflags.
1640
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001641- Fredrik Lundh's xmlrpclib is now a standard library module. This
1642 provides full client-side XML-RPC support. In addition,
1643 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1644 one asyncore-based). Thanks to Eric Raymond for the documentation.
1645
Guido van Rossum643d3912001-07-05 14:46:25 +00001646- The xrange() object is simplified: it no longer supports slicing,
1647 repetition, comparisons, efficient 'in' checking, the tolist()
1648 method, or the start, stop and step attributes. See PEP 260.
1649
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001650- A new function fnmatch.filter to filter lists of file names was added.
1651
Barry Warsawffd674d2001-05-22 16:00:10 +00001652- calendar.py uses month and day names based on the current locale.
1653
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001654- strop is now *really* obsolete (this was announced before with 1.6),
1655 and issues DeprecationWarning when used (except for the four items
1656 that are still imported into string.py).
1657
Tim Petersa814db52001-05-14 07:05:58 +00001658- Cookie.py now sorts key+value pairs by key in output strings.
1659
1660- pprint.isrecursive(object) didn't correctly identify recursive objects.
1661 Now it does.
1662
Tim Peters95b3f782001-05-14 18:39:41 +00001663- pprint functions now much faster for large containers (tuple, list, dict).
1664
Tim Peters7b9542a2001-06-10 23:40:19 +00001665- New 'q' and 'Q' format codes in the struct module, corresponding to C
1666 types "long long" and "unsigned long long" (on Windows, __int64). In
1667 native mode, these can be used only when the platform C compiler supports
1668 these types (when HAVE_LONG_LONG is #define'd by the Python config
1669 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001670 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1671 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001672
Guido van Rossum83213cc2001-06-12 16:48:52 +00001673- The site module installs a new built-in function 'help' that invokes
1674 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1675 it displays a message reminding the user to use 'help()' or
1676 'help(object)'.
1677
Tim Petersa814db52001-05-14 07:05:58 +00001678Tests
1679
1680- New test_mutants.py runs dict comparisons where the key and value
1681 comparison operators mutute the dicts randomly during comparison. This
1682 rapidly causes Python to crash under earlier releases (not for the faint
1683 of heart: it can also cause Win9x to freeze or reboot!).
1684
1685- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001686 pprint.isreadable() return sensible results. Also verifies that simple
1687 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001688
Tim Peters4324aa32001-05-28 22:30:08 +00001689C API
1690
1691- Removed the unused last_is_sticky argument from the internal
1692 _PyTuple_Resize(). If this affects you, you were cheating.
1693
1694
Guido van Rossum55a78992001-07-17 17:22:32 +00001695======================================================================
1696
1697
Guido van Rossumffe13be2001-04-16 18:46:45 +00001698What's New in Python 2.1 (final)?
1699=================================
1700
1701We only changed a few things since the last release candidate, all in
1702Python library code:
1703
1704- A bug in the locale module was fixed that affected locales which
1705 define no grouping for numeric formatting.
1706
1707- A few bugs in the weakref module's implementations of weak
1708 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1709 and the test suite was updated to check for these bugs.
1710
1711- An old bug in the os.path.walk() function (introduced in Python
1712 2.0!) was fixed: a non-existent file would cause an exception
1713 instead of being ignored.
1714
1715- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1716 PyChecker.
1717
1718
Guido van Rossum5b08f132001-04-16 02:05:23 +00001719What's New in Python 2.1c2?
1720===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001721
Guido van Rossum5b08f132001-04-16 02:05:23 +00001722A flurry of small changes, and one showstopper fixed in the nick of
1723time made it necessary to release another release candidate. The list
1724here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001725
Guido van Rossum5b08f132001-04-16 02:05:23 +00001726Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001727
Guido van Rossum5b08f132001-04-16 02:05:23 +00001728- Tim discovered a nasty bug in the dictionary code, caused by
1729 PyDict_Next() calling dict_resize(), and the GC code's use of
1730 PyDict_Next() violating an assumption in dict_items(). This was
1731 fixed with considerable amounts of band-aid, but the net effect is a
1732 saner and more robust implementation.
1733
1734- Made a bunch of symbols static that were accidentally global.
1735
1736Build and Ports
1737
1738- The setup.py script didn't check for a new enough version of zlib
1739 (1.1.3 is needed). Now it does.
1740
1741- Changed "make clean" target to also remove shared libraries.
1742
1743- Added a more general warning about the SGI Irix optimizer to README.
1744
1745Library
1746
1747- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1748 omitted the slash between host and file.html.
1749
1750- The mailbox module's _Mailbox class contained a completely broken
1751 and undocumented seek() method. Ripped it out.
1752
1753- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1754 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1755
1756- Fixed a few last-minute bugs in unittest.
1757
1758Extensions
1759
1760- Reverted the patch to the OpenSSL code in socketmodule.c to support
1761 RAND_status() and the EGD, and the subsequent patch that tried to
1762 fix it for pre-0.9.5 versions; the problem with the patch is that on
1763 some systems it issues a warning whenever socket is imported, and
1764 that's unacceptable.
1765
1766Tests
1767
1768- Fixed the pickle tests to work with "import test.test_pickle".
1769
1770- Tweaked test_locale.py to actually run the test Windows.
1771
1772- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1773 not "wb" (which is not a valid mode at all).
1774
1775- Fix pstats browser crashes. Import readline if it exists to make
1776 the user interface nicer.
1777
1778- Add "import thread" to the top of test modules that import the
1779 threading module (test_asynchat and test_threadedtempfile). This
1780 prevents test failures caused by a broken threading module resulting
1781 from a previously caught failed import.
1782
1783- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1784 needed on some platforms (e.g. Solaris 8) when the tests are run
1785 twice in succession.
1786
1787- Skip rather than fail test_sunaudiodev if no audio device is found.
1788
1789
1790What's New in Python 2.1c1?
1791===========================
1792
1793This list was significantly updated when 2.1c2 was released; the 2.1c1
1794release didn't mention most changes that were actually part of 2.1c1:
1795
1796Legal
1797
1798- Copyright was assigned to the Python Software Foundation (PSF) and a
1799 PSF license (very similar to the CNRI license) was added.
1800
1801- The CNRI copyright notice was updated to include 2001.
1802
1803Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001804
Guido van Rossumc9932722001-04-12 02:31:27 +00001805- After a public outcry, assignment to __debug__ is no longer illegal;
1806 instead, a warning is issued. It will become illegal in 2.2.
1807
Guido van Rossum5b08f132001-04-16 02:05:23 +00001808- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1809 "%#x" now always prepends "0x", even if the value is zero.
1810
1811- Fixed some nits in the bytecode compiler.
1812
1813- Fixed core dumps when calling certain kinds of non-functions.
1814
1815- Fixed various core dumps caused by reference count bugs.
1816
1817Build and Ports
1818
1819- Use INSTALL_SCRIPT to install script files.
1820
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001821- New port: SCO Unixware 7, by Billy G. Allie.
1822
Guido van Rossum5b08f132001-04-16 02:05:23 +00001823- Updated RISCOS port.
1824
1825- Updated BeOS port and notes.
1826
1827- Various other porting problems resolved.
1828
1829Library
1830
1831- The TERMIOS and SOCKET modules are now truly obsolete and
1832 unnecessary. Their symbols are incorporated in the termios and
1833 socket modules.
1834
1835- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1836 better tests for pickling.
1837
1838- threading: make Condition.wait() robust against KeyboardInterrupt.
1839
1840- zipfile: add support to zipfile to support opening an archive
1841 represented by an open file rather than a file name. Fix bug where
1842 the archive was not properly closed. Fixed a bug in this bugfix
1843 where flush() was called for a read-only file.
1844
1845- imputil: added an uninstall() method to the ImportManager.
1846
1847- Canvas: fixed bugs in lower() and tkraise() methods.
1848
1849- SocketServer: API change (added overridable close_request() method)
1850 so that the TCP server can explicitly close the request.
1851
1852- pstats: Eric Raymond added a simple interactive statistics browser,
1853 invoked when the module is run as a script.
1854
1855- locale: fixed a problem in format().
1856
1857- webbrowser: made it work when the BROWSER environment variable has a
1858 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1859 KDE 2. Fixed some other nits.
1860
1861- unittest: changes to allow using a different exception than
1862 AssertionError, and added a few more function aliases. Some other
1863 small changes.
1864
1865- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1866
1867- asynchat: fixed a critical bug in asynchat that slipped through the
1868 2.1b2 release. Fixed another rare bug.
1869
1870- Fix some unqualified except: clauses (always a bad code example).
1871
1872XML
1873
1874- pyexpat: new API get_version_string().
1875
1876- Fixed some minidom bugs.
1877
1878Extensions
1879
1880- Fixed a core dump in _weakref. Removed the weakref.mapping()
1881 function (it adds nothing to the API).
1882
1883- Rationalized the use of header files in the readline module, to make
1884 it compile (albeit with some warnings) with the very recent readline
1885 4.2, without breaking for earlier versions.
1886
1887- Hopefully fixed a buffering problem in linuxaudiodev.
1888
1889- Attempted a fix to make the OpenSSL support in the socket module
1890 work again with pre-0.9.5 versions of OpenSSL.
1891
1892Tests
1893
1894- Added a test case for asynchat and asyncore.
1895
1896- Removed coupling between tests where one test failing could break
1897 another.
1898
1899Tools
1900
1901- Ping added an interactive help browser to pydoc, fixed some nits
1902 in the rest of the pydoc code, and added some features to his
1903 inspect module.
1904
1905- An updated python-mode.el version 4.1 which integrates Ken
1906 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1907 much nicer in XEmacs and Emacs. When stepping through your program
1908 with pdb, in either the shell window or the *Python* window, the
1909 source file and line will be tracked by an arrow. Very cool!
1910
1911- IDLE: syntax warnings in interactive mode are changed into errors.
1912
1913- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001914 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001915
1916- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001917
Barry Warsaw11e89c72001-04-11 20:37:57 +00001918
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001919What's New in Python 2.1 beta 2?
1920================================
1921
Guido van Rossum053ae352001-03-22 14:17:21 +00001922(Unlisted are many fixed bugs, more documentation, etc.)
1923
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001924Core language, builtins, and interpreter
1925
Guido van Rossum053ae352001-03-22 14:17:21 +00001926- The nested scopes work (enabled by "from __future__ import
1927 nested_scopes") is completed; in particular, the future now extends
1928 into code executed through exec, eval() and execfile(), and into the
1929 interactive interpreter.
1930
1931- When calling a base class method (e.g. BaseClass.__init__(self)),
1932 this is now allowed even if self is not strictly spoken a class
1933 instance (e.g. when using metaclasses or the Don Beaudry hook).
1934
1935- Slice objects are now comparable but not hashable; this prevents
1936 dict[:] from being accepted but meaningless.
1937
1938- Complex division is now calculated using less braindead algorithms.
1939 This doesn't change semantics except it's more likely to give useful
1940 results in extreme cases. Complex repr() now uses full precision
1941 like float repr().
1942
1943- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1944
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001945- It is illegal to assign to the name __debug__, which is set when the
1946 interpreter starts. It is effectively a compile-time constant.
1947
1948- A warning will be issued if a global statement for a variable
1949 follows a use or assignment of that variable.
1950
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001951Standard library
1952
Guido van Rossum053ae352001-03-22 14:17:21 +00001953- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1954 inspired by JUnit), is now part of the standard library. You now
1955 have a choice of two testing frameworks: unittest requires you to
1956 write testcases as separate code, doctest gathers them from
1957 docstrings. Both approaches have their advantages and
1958 disadvantages.
1959
1960- A new module Tix was added, which wraps the Tix extension library
1961 for Tk. With that module, it is not necessary to statically link
1962 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1963 require" command. See Demo/tix/.
1964
1965- tzparse.py is now obsolete.
1966
1967- In gzip.py, the seek() and tell() methods are removed -- they were
1968 non-functional anyway, and it's better if callers can test for their
1969 existence with hasattr().
1970
1971Python/C API
1972
1973- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1974 that's already in the dictionary during a PyDict_Next() iteration.
1975 This used to fail occasionally when a dictionary resize operation
1976 could be triggered that would rehash all the keys. All other
1977 modifications to the dictionary are still off-limits during a
1978 PyDict_Next() iteration!
1979
1980- New extended APIs related to passing compiler variables around.
1981
1982- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1983 implement isinstance() and issubclass().
1984
1985- Py_BuildValue() now has a "D" conversion to create a Python complex
1986 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001987
Fred Drake4e262a92001-03-22 18:26:47 +00001988- Extensions types which support weak references must now set the
1989 field allocated for the weak reference machinery to NULL themselves;
1990 this is done to avoid the cost of checking each object for having a
1991 weakly referencable type in PyObject_INIT(), since most types are
1992 not weakly referencable.
1993
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001994- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1995 free variables and cell variables to and from the frame's f_locals.
1996
1997- Variants of several functions defined in pythonrun.h have been added
1998 to support the nested_scopes future statement. The variants all end
1999 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2000 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2001 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002002 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002003
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002004Distutils
2005
2006- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2007 into the release tree.
2008
Tim Peters0e57abf2001-05-02 07:39:38 +00002009- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002010 (an uninstaller, more customization of the installer's display)
2011
2012- from Jack Jansen: added Mac-specific code to generate a dialog for
2013 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002014 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002015 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002016
2017- added 'platforms' and 'keywords' to the set of metadata that can be
2018 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002019
2020- applied patches from Jason Tishler to make the compiler class work with
2021 Cygwin.
2022
2023
Tim Peters2fe289a2001-03-01 22:19:38 +00002024What's New in Python 2.1 beta 1?
2025================================
Tim Petersd66595f2001-02-04 03:09:53 +00002026
2027Core language, builtins, and interpreter
2028
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002029- Following an outcry from the community about the amount of code
2030 broken by the nested scopes feature introduced in 2.1a2, we decided
2031 to make this feature optional, and to wait until Python 2.2 (or at
2032 least 6 months) to make it standard. The option can be enabled on a
2033 per-module basis by adding "from __future__ import nested_scopes" at
2034 the beginning of a module (before any other statements, but after
2035 comments and an optional docstring). See PEP 236 (Back to the
2036 __future__) for a description of the __future__ statement. PEP 227
2037 (Statically Nested Scopes) has been updated to reflect this change,
2038 and to clarify the semantics in a number of endcases.
2039
2040- The nested scopes code, when enabled, has been hardened, and most
2041 bugs and memory leaks in it have been fixed.
2042
2043- Compile-time warnings are now generated for a number of conditions
2044 that will break or change in meaning when nested scopes are enabled:
2045
2046 - Using "from...import *" or "exec" without in-clause in a function
2047 scope that also defines a lambda or nested function with one or
2048 more free (non-local) variables. The presence of the import* or
2049 bare exec makes it impossible for the compiler to determine the
2050 exact set of local variables in the outer scope, which makes it
2051 impossible to determine the bindings for free variables in the
2052 inner scope. To avoid the warning about import *, change it into
2053 an import of explicitly name object, or move the import* statement
2054 to the global scope; to avoid the warning about bare exec, use
2055 exec...in... (a good idea anyway -- there's a possibility that
2056 bare exec will be deprecated in the future).
2057
2058 - Use of a global variable in a nested scope with the same name as a
2059 local variable in a surrounding scope. This will change in
2060 meaning with nested scopes: the name in the inner scope will
2061 reference the variable in the outer scope rather than the global
2062 of the same name. To avoid the warning, either rename the outer
2063 variable, or use a global statement in the inner function.
2064
Neil Schemenauera35c6882001-02-27 04:45:05 +00002065- An optional object allocator has been included. This allocator is
2066 optimized for Python objects and should be faster and use less memory
2067 than the standard system allocator. It is not enabled by default
2068 because of possible thread safety problems. The allocator is only
2069 protected by the Python interpreter lock and it is possible that some
2070 extension modules require a thread safe allocator. The object
2071 allocator can be enabled by providing the "--with-pymalloc" option to
2072 configure.
2073
Tim Petersd66595f2001-02-04 03:09:53 +00002074Standard library
2075
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002076- pyexpat now detects the expat version if expat.h defines it. A
2077 number of additional handlers are provided, which are only available
2078 since expat 1.95. In addition, the methods SetParamEntityParsing and
2079 GetInputContext of Parser objects are available with 1.95.x
2080 only. Parser objects now provide the ordered_attributes and
2081 specified_attributes attributes. A new module expat.model was added,
2082 which offers a number of additional constants if 1.95.x is used.
2083
2084- xml.dom offers the new functions registerDOMImplementation and
2085 getDOMImplementation.
2086
2087- xml.dom.minidom offers a toprettyxml method. A number of DOM
2088 conformance issues have been resolved. In particular, Element now
2089 has an hasAttributes method, and the handling of namespaces was
2090 improved.
2091
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002092- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2093 getting information about live Python code, and pydoc.py, a module
2094 for interactively converting docstrings to HTML or text.
2095 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002096 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002097 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2098 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002099
Tim Peters1eff7962001-03-01 02:31:33 +00002100- New library module difflib.py, primarily packaging the SequenceMatcher
2101 class at the heart of the popular ndiff.py file-comparison tool.
2102
2103- doctest.py (a framework for verifying Python code examples in docstrings)
2104 is now part of the std library.
2105
Tim Petersd66595f2001-02-04 03:09:53 +00002106Windows changes
2107
Guido van Rossume3955a82001-03-02 14:05:59 +00002108- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2109 small GUI that lets you browse the module docstrings using your
2110 default web browser.
2111
Tim Peters1eff7962001-03-01 02:31:33 +00002112- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2113 Platforms) is implemented. See
2114
2115 http://python.sourceforge.net/peps/pep-0235.html
2116
2117 for full details, especially the "Current Lower-Left Semantics" section.
2118 The new Windows import rules are simpler than before:
2119
2120 A. If the PYTHONCASEOK environment variable exists, same as
2121 before: silently accept the first case-insensitive match of any
2122 kind; raise ImportError if none found.
2123
2124 B. Else search sys.path for the first case-sensitive match; raise
2125 ImportError if none found.
2126
2127 The same rules have been implented on other platforms with case-
2128 insensitive but case-preserving filesystems too (including Cygwin, and
2129 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002130
Tim Peters25a9ce32001-02-19 07:06:36 +00002131- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2132 what it's supposed to do (and does do under NT and 2000) via direct
2133 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002134 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002135 all Win9x systems before.
2136
Tim Peters1eff7962001-03-01 02:31:33 +00002137- Build: Subproject _test (effectively) renamed to _testcapi.
2138
Tim Peters2fe289a2001-03-01 22:19:38 +00002139New platforms
2140
2141- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2142 Thanks to Steven Majewski!
2143
2144- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2145 Tishler!
2146
Guido van Rossum9089b272001-03-02 06:49:50 +00002147- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2148 Schwertberger! See RISCOS/README for more information -- it seems
2149 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002150 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002151
Tim Peters25a9ce32001-02-19 07:06:36 +00002152
Tim Petersd7b5e882001-01-25 03:36:26 +00002153What's New in Python 2.1 alpha 2?
2154=================================
Tim Peters40ead762001-01-27 05:35:26 +00002155
Tim Petersd7b5e882001-01-25 03:36:26 +00002156Core language, builtins, and interpreter
2157
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002158- Scopes nest. If a name is used in a function or class, but is not
2159 local, the definition in the nearest enclosing function scope will
2160 be used. One consequence of this change is that lambda statements
2161 could reference variables in the namespaces where the lambda is
2162 defined. In some unusual cases, this change will break code.
2163
2164 In all previous version of Python, names were resolved in exactly
2165 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002166 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002167 function A is defined within a function B, the names bound in B are
2168 not visible in A. The new rules make names bound in B visible in A,
2169 unless A contains a name binding that hides the binding in B.
2170
2171 Section 4.1 of the reference manual describes the new scoping rules
2172 in detail. The test script in Lib/test/test_scope.py demonstrates
2173 some of the effects of the change.
2174
2175 The new rules will cause existing code to break if it defines nested
2176 functions where an outer function has local variables with the same
2177 name as globals or builtins used by the inner function. Example:
2178
2179 def munge(str):
2180 def helper(x):
2181 return str(x)
2182 if type(str) != type(''):
2183 str = helper(str)
2184 return str.strip()
2185
2186 Under the old rules, the name str in helper() is bound to the
2187 builtin function str(). Under the new rules, it will be bound to
2188 the argument named str and an error will occur when helper() is
2189 called.
2190
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002191- The compiler will report a SyntaxError if "from ... import *" occurs
2192 in a function or class scope. The language reference has documented
2193 that this case is illegal, but the compiler never checked for it.
2194 The recent introduction of nested scope makes the meaning of this
2195 form of name binding ambiguous. In a future release, the compiler
2196 may allow this form when there is no possibility of ambiguity.
2197
Tim Peters40ead762001-01-27 05:35:26 +00002198- repr(string) is easier to read, now using hex escapes instead of octal,
2199 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2200
2201 >>> "\texample \r\n" + chr(0) + chr(255)
2202 '\texample \r\n\x00\xff' # in 2.1
2203 '\011example \015\012\000\377' # in 2.0
2204
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002205- Functions are now compared and hashed by identity, not by value, since
2206 the func_code attribute is writable.
2207
Fred Drakefb9d7122001-02-01 20:00:40 +00002208- Weak references (PEP 205) have been added. This involves a few
2209 changes in the core, an extension module (_weakref), and a Python
2210 module (weakref). The weakref module is the public interface. It
2211 includes support for "explicit" weak references, proxy objects, and
2212 mappings with weakly held values.
2213
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002214- A 'continue' statement can now appear in a try block within the body
2215 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002216 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002217
Tim Petersd7b5e882001-01-25 03:36:26 +00002218Standard library
2219
Barry Warsaw30dbd142001-01-31 22:14:01 +00002220- mailbox.py now has a new class, PortableUnixMailbox which is
2221 identical to UnixMailbox but uses a more portable scheme for
2222 determining From_ separators. Also, the constructors for all the
2223 classes in this module have a new optional `factory' argument, which
2224 is a callable used when new message classes must be instantiated by
2225 the next() method.
2226
Tim Petersd7b5e882001-01-25 03:36:26 +00002227- random.py is now self-contained, and offers all the functionality of
2228 the now-deprecated whrandom.py. See the docs for details. random.py
2229 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002230 and restoring the internal state of the generator; and jumpahead(n),
2231 for quickly forcing the internal state to be the same as if n calls to
2232 random() had been made. The latter is particularly useful for multi-
2233 threaded programs, creating one instance of the random.Random() class for
2234 each thread, then using .jumpahead() to force each instance to use a
2235 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002236
Tim Peters0de88fc2001-02-01 04:59:18 +00002237- random.py's seed() function is new. For bit-for-bit compatibility with
2238 prior releases, use the whseed function instead. The new seed function
2239 addresses two problems: (1) The old function couldn't produce more than
2240 about 2**24 distinct internal states; the new one about 2**45 (the best
2241 that can be done in the Wichmann-Hill generator). (2) The old function
2242 sometimes produced identical internal states when passed distinct
2243 integers, and there was no simple way to predict when that would happen;
2244 the new one guarantees to produce distinct internal states for all
2245 arguments in [0, 27814431486576L).
2246
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002247- The socket module now supports raw packets on Linux. The socket
2248 family is AF_PACKET.
2249
Tim Peters9ea17ac2001-02-02 05:57:15 +00002250- test_capi.py is a start at running tests of the Python C API. The tests
2251 are implemented by the new Modules/_testmodule.c.
2252
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002253- A new extension module, _symtable, provides provisional access to the
2254 internal symbol table used by the Python compiler. A higher-level
2255 interface will be added on top of _symtable in a future release.
2256
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002257- Removed the obsolete soundex module.
2258
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002259- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2260 the isSameNode method; NamedNodeMap the get method.
2261
2262- xml.sax.expatreader supports the lexical handler property; it
2263 generates comment, startCDATA, and endCDATA events.
2264
Tim Petersee826f82001-01-31 19:39:44 +00002265Windows changes
2266
2267- Build procedure: the zlib project is built in a different way that
2268 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002269 the zlib binary used. See PCbuild\readme.txt for details. Your old
2270 zlib-related directories can be deleted; you'll need to download fresh
2271 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002272
Tim Peters9ea17ac2001-02-02 05:57:15 +00002273- Build: New subproject _test for the benefit of test_capi.py (see above).
2274
Tim Petersb16c56f2001-02-02 21:24:51 +00002275- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2276 interface to some Python compiler internals).
2277
2278- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002279 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002280
Tim Petersa3a3a032000-11-30 05:22:44 +00002281What's New in Python 2.1 alpha 1?
2282=================================
2283
2284Core language, builtins, and interpreter
2285
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002286- There is a new Unicode companion to the PyObject_Str() API
2287 called PyObject_Unicode(). It behaves in the same way as the
2288 former, but assures that the returned value is an Unicode object
2289 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002290
Guido van Rossumf98eda02001-01-17 15:54:45 +00002291- The comparison operators support "rich comparison overloading" (PEP
2292 207). C extension types can provide a rich comparison function in
2293 the new tp_richcompare slot in the type object. The cmp() function
2294 and the C function PyObject_Compare() first try the new rich
2295 comparison operators before trying the old 3-way comparison. There
2296 is also a new C API PyObject_RichCompare() (which also falls back on
2297 the old 3-way comparison, but does not constrain the outcome of the
2298 rich comparison to a Boolean result).
2299
2300 The rich comparison function takes two objects (at least one of
2301 which is guaranteed to have the type that provided the function) and
2302 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2303 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2304 object, which may be NotImplemented (in which case the tp_compare
2305 slot function is used as a fallback, if defined).
2306
2307 Classes can overload individual comparison operators by defining one
2308 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002309 __ge__. There are no explicit "reflected argument" versions of
2310 these; instead, __lt__ and __gt__ are each other's reflection,
2311 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2312 reflection (similar at the C level). No other implications are
2313 made; in particular, Python does not assume that == is the Boolean
2314 inverse of !=, or that < is the Boolean inverse of >=. This makes
2315 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002316
2317 Classes or types that want to implement (in)equality tests but not
2318 the ordering operators (i.e. unordered types) should implement ==
2319 and !=, and raise an error for the ordering operators.
2320
Guido van Rossuma88479f2001-01-18 14:28:08 +00002321 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002322 Boolean; e.g. a matrix type might want to return a matrix of bits
2323 for A < B, giving elementwise comparisons. Such types should ensure
2324 that any interpretation of their value in a Boolean context raises
2325 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2326 at the C level) to always raise an exception.
2327
Guido van Rossuma88479f2001-01-18 14:28:08 +00002328- Complex numbers use rich comparisons to define == and != but raise
2329 an exception for <, <=, > and >=. Unfortunately, this also means
2330 that cmp() of two complex numbers raises an exception when the two
2331 numbers differ. Since it is not mathematically meaningful to compare
2332 complex numbers except for equality, I hope that this doesn't break
2333 too much code.
2334
Tim Peters3389f192001-02-18 08:48:49 +00002335- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002336 not defined by the language, other than that it's arbitrary but
2337 consistent (see the Reference Manual). An implementation detail changed
2338 in 2.1a1 such that None now compares less than any other object. Code
2339 relying on this new behavior (like code that relied on the previous
2340 behavior) does so at its own risk.
2341
Barry Warsaw573b5412001-01-15 20:43:18 +00002342- Functions and methods now support getting and setting arbitrarily
2343 named attributes (PEP 232). Functions have a new __dict__
2344 (a.k.a. func_dict) which hold the function attributes. Methods get
2345 and set attributes on their underlying im_func. It is a TypeError
2346 to set an attribute on a bound method.
2347
Guido van Rossum051e3352001-01-15 19:11:10 +00002348- The xrange() object implementation has been improved so that
2349 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2350 limitation that in this case len(xrange(sys.maxint)) can't be
2351 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2352 work fine as long as the index i doesn't actually reach 2**31.
2353 (Python uses regular ints for sequence and string indices; fixing
2354 that is much more work.)
2355
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002356- Two changes to from...import:
2357
Guido van Rossumba381232001-02-03 15:06:40 +00002358 1) "from M import X" now works even if (after loading module M)
2359 sys.modules['M'] is not a real module; it's basically a getattr()
2360 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002361
2362 2) "from M import *" now looks for M.__all__ to decide which names to
2363 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2364 filters out names starting with '_' as before. Whether or not
2365 __all__ exists, there's no restriction on the type of M.
2366
Guido van Rossumf61f1662001-01-10 20:13:55 +00002367- File objects have a new method, xreadlines(). This is the fastest
2368 way to iterate over all lines in a file:
2369
2370 for line in file.xreadlines():
2371 ...do something to line...
2372
2373 See the xreadlines module (mentioned below) for how to do this for
2374 other file-like objects.
2375
2376- Even if you don't use file.xreadlines(), you may expect a speedup on
2377 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002378 quite a bit in platform-specific ways: on systems (like Linux) that
2379 support flockfile(), getc_unlocked(), and funlockfile(), those are
2380 used by default. On systems (like Windows) without getc_unlocked(),
2381 a complicated (but still thread-safe) method using fgets() is used by
2382 default.
2383
Tim Petersd52269b2001-01-25 06:23:18 +00002384 You can force use of the fgets() method by #define'ing
2385 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002386 getc_unlocked()).
2387
Tim Petersd52269b2001-01-25 06:23:18 +00002388 You can force fgets() not to be used by #define'ing
2389 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002390 test_bufio.py fails -- and let us know if it does!).
2391
2392- In addition, the fileinput module, while still slower than the other
2393 methods on most platforms, has been sped up too, by using
2394 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002395
2396- Support for run-time warnings has been added, including a new
2397 command line option (-W) to specify the disposition of warnings.
2398 See the description of the warnings module below.
2399
2400- Extensive changes have been made to the coercion code. This mostly
2401 affects extension modules (which can now implement mixed-type
2402 numerical operators without having to use coercion), but
2403 occasionally, in boundary cases the coercion semantics have changed
2404 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002405 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002406 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002407 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002408
Guido van Rossumf98eda02001-01-17 15:54:45 +00002409- In connection with the coercion changes, a new built-in singleton
2410 object, NotImplemented is defined. This can be returned for
2411 operations that wish to indicate they are not implemented for a
2412 particular combination of arguments. From C, this is
2413 Py_NotImplemented.
2414
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002415- The interpreter accepts now bytecode files on the command line even
2416 if they do not have a .pyc or .pyo extension. On Linux, after executing
2417
Martin v. Löwise214baa2001-02-04 22:37:56 +00002418import imp,sys,string
2419magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2420reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2421open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002422
2423 any byte code file can be used as an executable (i.e. as an argument
2424 to execve(2)).
2425
Tim Peters9940b802000-12-01 07:59:35 +00002426- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002427 character. In 1.6 and earlier, they never produced a sign,
2428 and raised an error if the value of the long was too large
2429 to fit in a Python int. In 2.0, they produced a sign if and
2430 only if too large to fit in an int. This was inconsistent
2431 across platforms (because the size of an int varies across
2432 platforms), and inconsistent with hex() and oct(). Example:
2433
2434 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002435 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002436 'ffffffbe' # in 2.0 and before, on 32-bit machines
2437 >>> hex(-0x42L)
2438 '-0x42L' # in all versions of Python
2439
Tim Peters9940b802000-12-01 07:59:35 +00002440 The behavior of %d formats for negative Python longs remains
2441 the same as in 2.0 (although in 1.6 and before, they raised
2442 an error if the long didn't fit in a Python int).
2443
2444 %u formats don't make sense for Python longs, but are allowed
2445 and treated the same as %d in 2.1. In 2.0, a negative long
2446 formatted via %u produced a sign if and only if too large to
2447 fit in an int. In 1.6 and earlier, a negative long formatted
2448 via %u raised an error if it was too big to fit in an int.
2449
Guido van Rossum3661d392000-12-12 22:10:31 +00002450- Dictionary objects have an odd new method, popitem(). This removes
2451 an arbitrary item from the dictionary and returns it (in the form of
2452 a (key, value) pair). This can be useful for algorithms that use a
2453 dictionary as a bag of "to do" items and repeatedly need to pick one
2454 item. Such algorithms normally end up running in quadratic time;
2455 using popitem() they can usually be made to run in linear time.
2456
Tim Peters36cdad12000-12-29 02:06:45 +00002457Standard library
2458
Thomas Woutersfe385252001-01-19 23:16:56 +00002459- In the time module, the time argument to the functions strftime,
2460 localtime, gmtime, asctime and ctime is now optional, defaulting to
2461 the current time (in the local timezone).
2462
Guido van Rossumda91f222001-01-15 16:36:08 +00002463- The ftplib module now defaults to passive mode, which is deemed a
2464 more useful default given that clients are often inside firewalls
2465 these days. Note that this could break if ftplib is used to connect
2466 to a *server* that is inside a firewall, from outside; this is
2467 expected to be a very rare situation. To fix that, you can call
2468 ftp.set_pasv(0).
2469
Martin v. Löwis10a27872001-01-13 09:54:41 +00002470- The module site now treats .pth files not only for path configuration,
2471 but also supports extensions to the initialization code: Lines starting
2472 with import are executed.
2473
Guido van Rossumf61f1662001-01-10 20:13:55 +00002474- There's a new module, warnings, which implements a mechanism for
2475 issuing and filtering warnings. There are some new built-in
2476 exceptions that serve as warning categories, and a new command line
2477 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2478 turns warnings into errors). warnings.warn(message[, category])
2479 issues a warning message; this can also be called from C as
2480 PyErr_Warn(category, message).
2481
2482- A new module xreadlines was added. This exports a single factory
2483 function, xreadlines(). The intention is that this code is the
2484 absolutely fastest way to iterate over all lines in an open
2485 file(-like) object:
2486
2487 import xreadlines
2488 for line in xreadlines.xreadlines(file):
2489 ...do something to line...
2490
2491 This is equivalent to the previous the speed record holder using
2492 file.readlines(sizehint). Note that if file is a real file object
2493 (as opposed to a file-like object), this is equivalent:
2494
2495 for line in file.xreadlines():
2496 ...do something to line...
2497
Tim Peters36cdad12000-12-29 02:06:45 +00002498- The bisect module has new functions bisect_left, insort_left,
2499 bisect_right and insort_right. The old names bisect and insort
2500 are now aliases for bisect_right and insort_right. XXX_right
2501 and XXX_left methods differ in what happens when the new element
2502 compares equal to one or more elements already in the list: the
2503 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002504 right. Code that doesn't care where equal elements end up should
2505 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002506
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002507- The new curses.panel module wraps the panel library that forms part
2508 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2509
Guido van Rossumf61f1662001-01-10 20:13:55 +00002510- The SocketServer module now sets the allow_reuse_address flag by
2511 default in the TCPServer class.
2512
2513- A new function, sys._getframe(), returns the stack frame pointer of
2514 the caller. This is intended only as a building block for
2515 higher-level mechanisms such as string interpolation.
2516
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002517- The pyexpat module supports a number of new handlers, which are
2518 available only in expat 1.2. If invocation of a callback fails, it
2519 will report an additional frame in the traceback. Parser objects
2520 participate now in garbage collection. If expat reports an unknown
2521 encoding, pyexpat will try to use a Python codec; that works only
2522 for single-byte charsets. The parser type objects is exposed as
2523 XMLParserObject.
2524
2525- xml.dom now offers standard definitions for symbolic node type and
2526 exception code constants, and a hierarchy of DOM exceptions. minidom
2527 was adjusted to use them.
2528
2529- The conformance of xml.dom.minidom to the DOM specification was
2530 improved. It detects a number of additional error cases; the
2531 previous/next relationship works even when the tree is modified;
2532 Node supports the normalize() method; NamedNodeMap, DocumentType and
2533 DOMImplementation classes were added; Element supports the
2534 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2535 method.
2536
Guido van Rossumf61f1662001-01-10 20:13:55 +00002537Build issues
2538
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002539- For Unix (and Unix-compatible) builds, configuration and building of
2540 extension modules is now greatly automated. Rather than having to
2541 edit the Modules/Setup file to indicate which modules should be
2542 built and where their include files and libraries are, a
2543 distutils-based setup.py script now takes care of building most
2544 extension modules. All extension modules built this way are built
2545 as shared libraries. Only a few modules that must be linked
2546 statically are still listed in the Setup file; you won't need to
2547 edit their configuration.
2548
2549- Python should now build out of the box on Cygwin. If it doesn't,
2550 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002551
2552- Python now always uses its own (renamed) implementation of getopt()
2553 -- there's too much variation among C library getopt()
2554 implementations.
2555
2556- C++ compilers are better supported; the CXX macro is always set to a
2557 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002558
Tim Petersd92dfe02000-12-12 01:18:41 +00002559Windows changes
2560
2561- select module: By default under Windows, a select() call
2562 can specify no more than 64 sockets. Python now boosts
2563 this Microsoft default to 512. If you need even more than
2564 that, see the MS docs (you'll need to #define FD_SETSIZE
2565 and recompile Python from source).
2566
Guido van Rossumf61f1662001-01-10 20:13:55 +00002567- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2568 subdirectory is no more!
2569
Tim Petersa3a3a032000-11-30 05:22:44 +00002570
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002571What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002572=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002573
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002574Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002575changes are in the file HISTORY. If you are making the jump directly
2576from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2577HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002578
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002579Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2580the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2581http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002582
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002583--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002584
2585======================================================================
2586
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002587What's new in 2.0 (since release candidate 1)?
2588==============================================
2589
2590Standard library
2591
2592- The copy_reg module was modified to clarify its intended use: to
2593 register pickle support for extension types, not for classes.
2594 pickle() will raise a TypeError if it is passed a class.
2595
2596- Fixed a bug in gettext's "normalize and expand" code that prevented
2597 it from finding an existing .mo file.
2598
2599- Restored support for HTTP/0.9 servers in httplib.
2600
Tim Peters989b7b92000-10-16 20:24:53 +00002601- The math module was changed to stop raising OverflowError in case of
2602 underflow, and return 0 instead in underflow cases. Whether Python
2603 used to raise OverflowError in case of underflow was platform-
2604 dependent (it did when the platform math library set errno to ERANGE
2605 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002606
2607- Fixed a bug in StringIO that occurred when the file position was not
2608 at the end of the file and write() was called with enough data to
2609 extend past the end of the file.
2610
2611- Fixed a bug that caused Tkinter error messages to get lost on
2612 Windows. The bug was fixed by replacing direct use of
2613 interp->result with Tcl_GetStringResult(interp).
2614
2615- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2616 redirect response.
2617
2618- Several changes were made to distutils: Some debugging code was
2619 removed from util. Fixed the installer used when an external zip
2620 program (like WinZip) is not found; the source code for this
2621 installer is in Misc/distutils. check_lib() was modified to behave
2622 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2623 test for whether installed modules are on sys.path was changed to
2624 use both normcase() and normpath().
2625
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002626- Several minor bugs were fixed in the xml package (the minidom,
2627 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002628
2629- The regression test driver (regrtest.py) behavior when invoked with
2630 -l changed: It now reports a count of objects that are recognized as
2631 garbage but not freed by the garbage collector.
2632
Tim Peters989b7b92000-10-16 20:24:53 +00002633- The regression test for the math module was changed to test
2634 exceptional behavior when the test is run in verbose mode. Python
2635 cannot yet guarantee consistent exception behavior across platforms,
2636 so the exception part of test_math is run only in verbose mode, and
2637 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002638
2639Internals
2640
2641- PyOS_CheckStack() has been disabled on Win64, where it caused
2642 test_sre to fail.
2643
2644Build issues
2645
2646- Changed compiler flags, so that gcc is always invoked with -Wall and
2647 -Wstrict-prototypes. Users compiling Python with GCC should see
2648 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002649 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002650 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002651
Tim Petersa3a3a032000-11-30 05:22:44 +00002652- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002653
2654Tools and other miscellany
2655
2656- The compiler in Tools/compiler was updated to support the new
2657 language features introduced in 2.0: extended print statement, list
2658 comprehensions, and augmented assignments. The new compiler should
2659 also be backwards compatible with Python 1.5.2; the compiler will
2660 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002661 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002662
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002663What's new in 2.0 release candidate 1 (since beta 2)?
2664=====================================================
2665
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002666What is release candidate 1?
2667
2668We believe that release candidate 1 will fix all known bugs that we
2669intend to fix for the 2.0 final release. This release should be a bit
2670more stable than the previous betas. We would like to see even more
2671widespread testing before the final release, so we are producing this
2672release candidate. The final release will be exactly the same unless
2673any show-stopping (or brown bag) bugs are found by testers of the
2674release candidate.
2675
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002676All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002677to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002678
2679Core language, builtins, and interpreter
2680
2681- A bug that caused crashes when __coerce__ was used with augmented
2682 assignment, e.g. +=, was fixed.
2683
2684- Raise ZeroDivisionError when raising zero to a negative number,
2685 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2686 power operator and the result of math.pow(0.0, -2.0) will vary by
2687 platform. On Linux, it raises a ValueError.
2688
2689- A bug in Unicode string interpolation was fixed that occasionally
2690 caused errors with formats including "%%". For example, the
2691 following expression "%% %s" % u"abc" no longer raises a TypeError.
2692
2693- Compilation of deeply nested expressions raises MemoryError instead
2694 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2695
2696- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2697 rendering them useless. They are now written in binary mode again.
2698
2699Standard library
2700
2701- Keyword arguments are now accepted for most pattern and match object
2702 methods in SRE, the standard regular expression engine.
2703
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002704- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002705 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002706
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002707- Several bugs in the Unicode handling and error handling in _tkinter
2708 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002709
2710- Fix memory management errors in Merge() and Tkapp_Call() routines.
2711
2712- Several changes were made to cStringIO to make it compatible with
2713 the file-like object interface and with StringIO. If operations are
2714 performed on a closed object, an exception is raised. The truncate
2715 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002716 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002717
2718- There were many changes made to the linuxaudiodev module and its
2719 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002720 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002721
2722 Note that this module is named poorly, because it should work
2723 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002724 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002725
2726 The module now raises exceptions when errors occur instead of
2727 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2728 audio) and defines a getptr() method that calls the
2729 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2730
2731- The library_version attribute, introduced in an earlier beta, was
2732 removed because it can not be supported with early versions of the C
2733 readline library, which provides no way to determine the version at
2734 compile-time.
2735
2736- The binascii module is now enabled on Win64.
2737
Tim Peters46446d62000-10-09 21:19:31 +00002738- tokenize.py no longer suffers "recursion depth" errors when parsing
2739 programs with very long string literals.
2740
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002741Internals
2742
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002743- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002744 which is called when the interpreter starts up to determine where
2745 the standard library is installed. These vulnerabilities affect all
2746 previous versions of Python and can be exploited by setting very
2747 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2748 setuid Python script, although use of the wrapper in
2749 Misc/setuid-prog.c will eliminate the vulnerability.
2750
2751- Fixed garbage collection bugs in instance creation that were
2752 triggered when errors occurred during initialization. The solution,
2753 applied in cPickle and in PyInstance_New(), is to call
2754 PyObject_GC_Init() after the initialization of the object's
2755 container attributes is complete.
2756
2757- pyexpat adds definitions of PyModule_AddStringConstant and
2758 PyModule_AddObject if the Python version is less than 2.0, which
2759 provides compatibility with PyXML on Python 1.5.2.
2760
2761- If the platform has a bogus definition for LONG_BIT (the number of
2762 bits in a long), an error will be reported at compile time.
2763
2764- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2765 collection crashes and possibly other, unreported crashes.
2766
2767- Fixed a memory leak in _PyUnicode_Fini().
2768
2769Build issues
2770
2771- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002772 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002773 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002774
2775- The mmap.PAGESIZE constant is now initialized using sysconf when
2776 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2777
2778- The md5 file should now compile on all platforms.
2779
2780- The select module now compiles on platforms that do not define
2781 POLLRDNORM and related constants.
2782
2783- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002784 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002785
Jeremy Hylton10921202000-10-09 18:34:12 +00002786- BeOS: A number of changes were made to the build and installation
2787 process. ar-fake now operates on a directory of object files.
2788 dl_export.h is gone, and its macros now appear on the mwcc command
2789 line during build on PPC BeOS.
2790
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002791- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002792 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002793
2794- Cygwin: Support for shared libraries, Tkinter, and sockets.
2795
2796- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2797
2798Tools and other miscellany
2799
2800- Removed debugging prints from main used with freeze.
2801
Tim Peters46446d62000-10-09 21:19:31 +00002802- IDLE auto-indent no longer crashes when it encounters Unicode
2803 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002804
2805What's new in 2.0 beta 2 (since beta 1)?
2806========================================
2807
2808Core language, builtins, and interpreter
2809
Tim Peters482c0212000-09-26 06:33:09 +00002810- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002811 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002812
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002813- Add -h and -V command line options to print the usage message and
2814 Python version number and exit immediately.
2815
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002816- eval() and exec accept Unicode objects as code parameters.
2817
2818- getattr() and setattr() now also accept Unicode objects for the
2819 attribute name, which are converted to strings using the default
2820 encoding before lookup.
2821
2822- Multiplication on string and Unicode now does proper bounds
2823 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2824 string is too long."
2825
2826- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002827 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002828
Jeremy Hylton1b618592000-09-26 05:32:36 +00002829
2830Standard library and extensions
2831
Guido van Rossum5b08f132001-04-16 02:05:23 +00002832- socket module: the OpenSSL code now adds support for RAND_status()
2833 and EGD (Entropy Gathering Device).
2834
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002835- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002836 argument checking; it still takes no arguments.
2837
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002838- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002840- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002842- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002843
2844- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002845 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002846
2847- copy: Copy Unicode objects atomically.
2848
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002849- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002850
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002851- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002852
Fred Drake67233bc2000-09-26 16:40:27 +00002853- dbm: Add get() and setdefault() methods to dbm object. Add constant
2854 `library' to module that names the library used. Added doc strings
2855 and method names to error messages. Uses configure to determine
2856 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2857 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002858
2859- distutils: Update to version 0.9.3.
2860
2861- dl: Add several dl.RTLD_ constants.
2862
2863- fpectl: Now supported on FreeBSD.
2864
2865- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2866 found by the collector will be saved in gc.garbage. This is useful
2867 for debugging a program that creates reference cycles.
2868
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002869- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002870 of HTTP class. Do not close socket on zero-length response. Do not
2871 crash when server sends invalid content-length header.
2872
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002873- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002875- marshal: When reading a short, sign-extend on platforms where shorts
2876 are bigger than 16 bits. When reading a long, repair the unportable
2877 sign extension that was being done for 64-bit machines. (It assumed
2878 that signed right shift sign-extends.)
2879
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002880- operator: Add contains(), invert(), __invert__() as aliases for
2881 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002883- os: Add support for popen2() and popen3() on all platforms where
2884 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002885
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002886- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002887 clicking on a file in Explorer (or passing the file name to the
2888 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002889
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002890- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002891 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002892
2893- pickle: Now raises ValueError when an invalid pickle that contains
2894 a non-string repr where a string repr was expected. This behavior
2895 matches cPickle.
2896
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002897- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002898
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002899- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002900
2901- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002902 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002903 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002904
2905- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002906 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002907
2908- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002909 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002910 few cycles during startup since the first call to
2911 setdefaultencoding() will initialize the codec registry and the
2912 encodings package.
2913
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002914- socket: Support for size hint in readlines() method of object returned
2915 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002916
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002917- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002918 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002919 is followed by whitespace.
2920
Tim Petersa3a3a032000-11-30 05:22:44 +00002921- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002922
2923- struct: Check ranges for bytes and shorts.
2924
2925- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002926 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002927
2928- Tkinter: Image objects are now guaranteed to have unique ids. Set
2929 event.delta to zero if Tk version doesn't support mousewheel.
2930 Removed some debugging prints.
2931
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002932- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002933
Fred Drake67233bc2000-09-26 16:40:27 +00002934- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002935 which works around a bug in Norton AntiVirus 2000 that leads directly
2936 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002937
2938- xml: New version detection code allows PyXML to override standard
2939 XML package if PyXML version is greater than 0.6.1.
2940
Fred Drake64bb3802000-09-26 16:21:35 +00002941- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2942 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2943 tree only for nodes which are sufficiently interesting to a specific
2944 application. Does not provide the HTML-specific extensions. Still
2945 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002946
Fred Drake64bb3802000-09-26 16:21:35 +00002947- xml.sax: SAX 2 support for Python, including all the handler
2948 interfaces needed to process XML 1.0 compliant XML. Some
2949 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002950
Fred Drake64bb3802000-09-26 16:21:35 +00002951- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2952 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002953
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002954
Jeremy Hylton1b618592000-09-26 05:32:36 +00002955C API
2956
2957- Add three new convenience functions for module initialization --
2958 PyModule_AddObject(), PyModule_AddIntConstant(), and
2959 PyModule_AddStringConstant().
2960
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002961- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002962 removed and add #error to Python.h if NULL isn't defined after
2963 #include of stdio.h.
2964
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002965- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002966 backwards compatibility (at the source level) with old extensions.
2967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002968- A wrapper API was added for signal() and sigaction(). Instead of
2969 either function, always use PyOS_getsig() to get a signal handler
2970 and PyOS_setsig() to set one. A new convenience typedef
2971 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002972
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002973- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002974 internal data buffer and size of a string object -- or the default
2975 encoded version of a Unicode object.
2976
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002977- PyString_Size() and PyString_AsString() accept Unicode objects.
2978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002979- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002980 exists). INT_MAX and LONG_MAX will always be defined, even if
2981 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002982
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002983- PyFloat_FromString takes a second argument, pend, that was
2984 effectively useless. It is now officially useless but preserved for
2985 backwards compatibility. If the pend argument is not NULL, *pend is
2986 set to NULL.
2987
2988- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2989 for the attribute name. See note on getattr() above.
2990
2991- A few bug fixes to argument processing for Unicode.
2992 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2993 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2994 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002995 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002996
2997- Py_BuildValue accepts B format (for bgen-generated code).
2998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002999
Jeremy Hylton1b618592000-09-26 05:32:36 +00003000Internals
3001
3002- On Unix, fix code for finding Python installation directory so that
3003 it works when argv[0] is a relative path.
3004
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003005- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003006 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003007 rather than by generating a copy of the object.
3008
Tim Peters482c0212000-09-26 06:33:09 +00003009- Several of the internal Unicode tables are much smaller now, and
3010 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003011
Jeremy Hylton97693b02000-09-26 17:42:51 +00003012- In the garbage collector: Fixed bug in collection of tuples. Fixed
3013 bug that caused some instances to be removed from the container set
3014 while they were still live. Fixed parsing in gc.set_debug() for
3015 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003016
3017- Fixed refcount problem in instance deallocation that only occurred
3018 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3019
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003020- On Windows, getpythonregpath is now protected against null data in
3021 registry key.
3022
3023- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003024 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003025
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003026
Jeremy Hylton1b618592000-09-26 05:32:36 +00003027Build and platform-specific issues
3028
3029- Better support of GNU Pth via --with-pth configure option.
3030
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003031- Python/C API now properly exposed to dynamically-loaded extension
3032 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003033
3034- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3035 Don't define MS_SYNC to be zero when it is undefined. Added missing
3036 prototypes in posixmodule.c.
3037
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003038- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003039 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003040
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003041- Fix largefile support on older NetBSD systems and OpenBSD by adding
3042 define for TELL64.
3043
3044
3045Tools and other miscellany
3046
3047- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3048
3049- freeze: The modulefinder now works with 2.0 opcodes.
3050
Tim Petersa3a3a032000-11-30 05:22:44 +00003051- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003052 Move hackery of sys.argv until after the Tk instance has been
3053 created, which allows the application-specific Tkinter
3054 initialization to be executed if present; also pass an explicit
3055 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003056
Jeremy Hylton1b618592000-09-26 05:32:36 +00003057
3058What's new in 2.0 beta 1?
3059=========================
3060
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003061Source Incompatibilities
3062------------------------
3063
3064None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3065such as single-argument append(), connect() and bind(), and changes to
3066str(long) and repr(float).
3067
3068
3069Binary Incompatibilities
3070------------------------
3071
3072- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3073with Python 2.0; these extensions will have to be rebuilt for Python
30742.0.
3075
3076- On Windows, attempting to import a third party extension built for
3077Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3078can do about this. Check your PYTHONPATH environment variable!
3079
3080- Python bytecode files (*.pyc and *.pyo) are not compatible between
3081releases.
3082
3083
3084Overview of Changes Since 1.6
3085-----------------------------
3086
3087There are many new modules (including brand new XML support through
3088the xml package, and i18n support through the gettext module); a list
3089of all new modules is included below. Lots of bugs have been fixed.
3090
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003091The process for making major new changes to the language has changed
3092since Python 1.6. Enhancements must now be documented by a Python
3093Enhancement Proposal (PEP) before they can be accepted.
3094
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003095There are several important syntax enhancements, described in more
3096detail below:
3097
3098 - Augmented assignment, e.g. x += 1
3099
3100 - List comprehensions, e.g. [x**2 for x in range(10)]
3101
3102 - Extended import statement, e.g. import Module as Name
3103
3104 - Extended print statement, e.g. print >> file, "Hello"
3105
3106Other important changes:
3107
3108 - Optional collection of cyclical garbage
3109
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003110Python Enhancement Proposal (PEP)
3111---------------------------------
3112
3113PEP stands for Python Enhancement Proposal. A PEP is a design
3114document providing information to the Python community, or describing
3115a new feature for Python. The PEP should provide a concise technical
3116specification of the feature and a rationale for the feature.
3117
3118We intend PEPs to be the primary mechanisms for proposing new
3119features, for collecting community input on an issue, and for
3120documenting the design decisions that have gone into Python. The PEP
3121author is responsible for building consensus within the community and
3122documenting dissenting opinions.
3123
3124The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003125
3126Augmented Assignment
3127--------------------
3128
3129This must have been the most-requested feature of the past years!
3130Eleven new assignment operators were added:
3131
Guido van Rossume905e952000-09-05 12:42:46 +00003132 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003133
3134For example,
3135
3136 A += B
3137
3138is similar to
3139
3140 A = A + B
3141
3142except that A is evaluated only once (relevant when A is something
3143like dict[index].attr).
3144
3145However, if A is a mutable object, A may be modified in place. Thus,
3146if A is a number or a string, A += B has the same effect as A = A+B
3147(except A is only evaluated once); but if a is a list, A += B has the
3148same effect as A.extend(B)!
3149
3150Classes and built-in object types can override the new operators in
3151order to implement the in-place behavior; the not-in-place behavior is
3152used automatically as a fallback when an object doesn't implement the
3153in-place behavior. For classes, the method name is derived from the
3154method name for the corresponding not-in-place operator by inserting
3155an 'i' in front of the name, e.g. __iadd__ implements in-place
3156__add__.
3157
3158Augmented assignment was implemented by Thomas Wouters.
3159
3160
3161List Comprehensions
3162-------------------
3163
3164This is a flexible new notation for lists whose elements are computed
3165from another list (or lists). The simplest form is:
3166
3167 [<expression> for <variable> in <sequence>]
3168
Guido van Rossum56db0952000-09-06 23:34:25 +00003169For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003170This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003171
3172You can also add a condition:
3173
3174 [<expression> for <variable> in <sequence> if <condition>]
3175
3176For example, [w for w in words if w == w.lower()] would yield the list
3177of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003178than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003179
3180You can also have nested for loops and more than one 'if' clause. For
3181example, here's a function that flattens a sequence of sequences::
3182
3183 def flatten(seq):
3184 return [x for subseq in seq for x in subseq]
3185
3186 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3187
3188This prints
3189
3190 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3191
3192List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003193Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003194
3195
3196Extended Import Statement
3197-------------------------
3198
3199Many people have asked for a way to import a module under a different
3200name. This can be accomplished like this:
3201
3202 import foo
3203 bar = foo
3204 del foo
3205
3206but this common idiom gets old quickly. A simple extension of the
3207import statement now allows this to be written as follows:
3208
3209 import foo as bar
3210
3211There's also a variant for 'from ... import':
3212
3213 from foo import bar as spam
3214
3215This also works with packages; e.g. you can write this:
3216
3217 import test.regrtest as regrtest
3218
3219Note that 'as' is not a new keyword -- it is recognized only in this
3220context (this is only possible because the syntax for the import
3221statement doesn't involve expressions).
3222
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003223Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003224
3225
3226Extended Print Statement
3227------------------------
3228
3229Easily the most controversial new feature, this extension to the print
3230statement adds an option to make the output go to a different file
3231than the default sys.stdout.
3232
3233For example, to write an error message to sys.stderr, you can now
3234write:
3235
3236 print >> sys.stderr, "Error: bad dog!"
3237
3238As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003239evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003240
3241 print >> None, "Hello world"
3242
3243is equivalent to
3244
3245 print "Hello world"
3246
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003247Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003248
3249
3250Optional Collection of Cyclical Garbage
3251---------------------------------------
3252
3253Python is now equipped with a garbage collector that can hunt down
3254cyclical references between Python objects. It's no replacement for
3255reference counting; in fact, it depends on the reference counts being
3256correct, and decides that a set of objects belong to a cycle if all
3257their reference counts can be accounted for from their references to
3258each other. This devious scheme was first proposed by Eric Tiedemann,
3259and brought to implementation by Neil Schemenauer.
3260
3261There's a module "gc" that lets you control some parameters of the
3262garbage collection. There's also an option to the configure script
3263that lets you enable or disable the garbage collection. In 2.0b1,
3264it's on by default, so that we (hopefully) can collect decent user
3265experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003266performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003267off by default in the final 2.0 release.
3268
3269
3270Smaller Changes
3271---------------
3272
3273A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3274map(None, seq1, seq2, ...) when the sequences have the same length;
3275i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3276the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003277zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003278
3279sys.version_info is a tuple (major, minor, micro, level, serial).
3280
3281Dictionaries have an odd new method, setdefault(key, default).
3282dict.setdefault(key, default) returns dict[key] if it exists; if not,
3283it sets dict[key] to default and returns that value. Thus:
3284
3285 dict.setdefault(key, []).append(item)
3286
3287does the same work as this common idiom:
3288
3289 if not dict.has_key(key):
3290 dict[key] = []
3291 dict[key].append(item)
3292
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003293There are two new variants of SyntaxError that are raised for
3294indentation-related errors: IndentationError and TabError.
3295
3296Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3297escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003298
3299The limits on the size of expressions and file in Python source code
3300have been raised from 2**16 to 2**32. Previous versions of Python
3301were limited because the maximum argument size the Python VM accepted
3302was 2**16. This limited the size of object constructor expressions,
3303e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3304limit was raised thanks to a patch by Charles Waldman that effectively
3305fixes the problem. It is now much more likely that you will be
3306limited by available memory than by an arbitrary limit in Python.
3307
3308The interpreter's maximum recursion depth can be modified by Python
3309programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3310limit is the maximum number of recursive calls that can be made by
3311Python code. The limit exists to prevent infinite recursion from
3312overflowing the C stack and causing a core dump. The default value is
33131000. The maximum safe value for a particular platform can be found
3314by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003315
3316New Modules and Packages
3317------------------------
3318
3319atexit - for registering functions to be called when Python exits.
3320
3321imputil - Greg Stein's alternative API for writing custom import
3322hooks.
3323
3324pyexpat - an interface to the Expat XML parser, contributed by Paul
3325Prescod.
3326
3327xml - a new package with XML support code organized (so far) in three
3328subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3329would fill a volume. There's a special feature whereby a
3330user-installed package named _xmlplus overrides the standard
3331xmlpackage; this is intended to give the XML SIG a hook to distribute
3332backwards-compatible updates to the standard xml package.
3333
3334webbrowser - a platform-independent API to launch a web browser.
3335
3336
Guido van Rossume905e952000-09-05 12:42:46 +00003337Changed Modules
3338---------------
3339
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003340array -- new methods for array objects: count, extend, index, pop, and
3341remove
3342
3343binascii -- new functions b2a_hex and a2b_hex that convert between
3344binary data and its hex representation
3345
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003346calendar -- Many new functions that support features including control
3347over which day of the week is the first day, returning strings instead
3348of printing them. Also new symbolic constants for days of week,
3349e.g. MONDAY, ..., SUNDAY.
3350
3351cgi -- FieldStorage objects have a getvalue method that works like a
3352dictionary's get method and returns the value attribute of the object.
3353
3354ConfigParser -- The parser object has new methods has_option,
3355remove_section, remove_option, set, and write. They allow the module
3356to be used for writing config files as well as reading them.
3357
3358ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003359optionally support the RFC 959 REST command.
3360
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003361gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003362
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003363httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3364the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003365
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003366locale -- implement getdefaultlocale for Win32 and Macintosh
3367
3368marshal -- no longer dumps core when marshaling deeply nested or
3369recursive data structures
3370
3371os -- new functions isatty, seteuid, setegid, setreuid, setregid
3372
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003373os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3374support under Unix.
3375
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003376os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003377
3378os.path -- fix semantics of os.path.commonprefix
3379
3380smtplib -- support for sending very long messages
3381
3382socket -- new function getfqdn()
3383
3384readline -- new functions to read, write and truncate history files.
3385The readline section of the library reference manual contains an
3386example.
3387
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003388select -- add interface to poll system call
3389
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003390shutil -- new copyfileobj function
3391
3392SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3393HTTP server.
3394
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003395Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003396
3397urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003398e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003399
3400whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003401
3402
3403Obsolete Modules
3404----------------
3405
3406None. However note that 1.6 made a whole slew of modules obsolete:
3407stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3408poly, zmod, strop, util, whatsound.
3409
3410
3411Changed, New, Obsolete Tools
3412----------------------------
3413
Tim Peters8b092332000-09-05 20:15:25 +00003414None.
Guido van Rossume905e952000-09-05 12:42:46 +00003415
3416
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003417C-level Changes
3418---------------
3419
3420Several cleanup jobs were carried out throughout the source code.
3421
3422All C code was converted to ANSI C; we got rid of all uses of the
3423Py_PROTO() macro, which makes the header files a lot more readable.
3424
3425Most of the portability hacks were moved to a new header file,
3426pyport.h; several other new header files were added and some old
3427header files were removed, in an attempt to create a more rational set
3428of header files. (Few of these ever need to be included explicitly;
3429they are all included by Python.h.)
3430
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003431Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003432and Win64, especially for the new Intel Itanium processor. Mick also
3433added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003434
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003435The C APIs to return an object's size have been update to consistently
3436use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3437previous versions, the abstract interfaces used PyXXX_Length and the
3438concrete interfaces used PyXXX_Size. The old names,
3439e.g. PyObject_Length, are still available for backwards compatibility
3440at the API level, but are deprecated.
3441
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003442The PyOS_CheckStack function has been implemented on Windows by
3443Fredrik Lundh. It prevents Python from failing with a stack overflow
3444on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003445
3446The GC changes resulted in creation of two new slots on object,
3447tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003448the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003449
3450The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003451C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003452
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003453PyErr_Format has been updated to automatically calculate the size of
3454the buffer needed to hold the formatted result string. This change
3455prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003456
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003457New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003458
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003459PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3460that are the same as their non-Ex counterparts except they take an
3461extra flag argument that tells them to close the file when done.
3462
3463XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003464
Tim Peters8b092332000-09-05 20:15:25 +00003465
3466Windows Changes
3467---------------
3468
3469New popen2/popen3/peopen4 in os module (see Changed Modules above).
3470
3471os.popen is much more usable on Windows 95 and 98. See Microsoft
3472Knowledge Base article Q150956. The Win9x workaround described there
3473is implemented by the new w9xpopen.exe helper in the root of your
3474Python installation. Note that Python uses this internally; it is not
3475a standalone program.
3476
3477Administrator privileges are no longer required to install Python
3478on Windows NT or Windows 2000. If you have administrator privileges,
3479Python's registry info will be written under HKEY_LOCAL_MACHINE.
3480Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003481under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003482uses of Python, but will prevent some advanced uses from working
3483(for example, running a Python script as an NT service, or possibly
3484from CGI).
3485
3486[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3487installer; instead, it installs the needed Tcl/Tk files directly in the
3488Python directory. If you already have a Tcl/Tk installation, this
3489wastes some disk space (about 4 Megs) but avoids problems with
3490conflicting Tcl/Tk installations, and makes it much easier for Python
3491to ensure that Tcl/Tk can find all its files.
3492
3493[This was new in 1.6] The Windows installer now installs by default in
3494\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3495
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003496
3497Updates to the changes between 1.5.2 and 1.6
3498--------------------------------------------
3499
3500The 1.6 NEWS file can't be changed after the release is done, so here
3501is some late-breaking news:
3502
3503New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3504and changes to getlocale() and setlocale().
3505
3506The new module is now enabled per default.
3507
3508It is not true that the encodings codecs cannot be used for normal
3509strings: the string.encode() (which is also present on 8-bit strings
3510!) allows using them for 8-bit strings too, e.g. to convert files from
3511cp1252 (Windows) to latin-1 or vice-versa.
3512
3513Japanese codecs are available from Tamito KAJIYAMA:
3514http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3515
3516
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003517======================================================================