blob: 4a949f4b377f58e5d26253a21255fe27936c891e [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
Neal Norwitz1f68fc72002-06-14 00:50:42 +00009- Fixed string.startswith and string.endswith builtin methods
10 so they accept negative indices. [SF bug 493951]
11
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +000012- Fixed a bug with a continue inside a try block and a yield in the
13 finally clause. [SF bug 567538]
14
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +000015- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +000016 with a third "stride" parameter. For example, "hello world"[::-1]
17 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +000018
Guido van Rossum9f7549b2002-06-10 21:39:42 +000019- Cycles going through the __class__ link of a new-style instance are
20 now detected by the garbage collector.
21
Guido van Rossum9923ffe2002-06-04 19:52:53 +000022- Classes using __slots__ are now properly garbage collected.
23 [SF bug 519621]
24
25- Tightened the __slots__ rules: a slot name must be a valid Python
26 identifier.
27
Guido van Rossum2e4e0262002-06-04 05:58:34 +000028- The constructor for the module type now requires a name argument and
29 takes an optional docstring argument. Previously, this constructor
30 ignored its arguments. As a consequence, deriving a class from a
31 module (not from the module type) is now illegal; previously this
32 created an unnamed module, just like invoking the module type did.
33 [SF bug 563060]
34
Neal Norwitzd68f5172002-05-29 15:54:55 +000035- A new warning PendingDeprecationWarning was added to provide
36 direction on features which are in the process of being deprecated.
37 The warning will not be printed by default. To see the pending
38 deprecations, use -Walways::PendingDeprecationWarning::
39 as a command line option or warnings.filterwarnings() in code.
40
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000041- A new type object, 'basestring', is added. This is a common base type
Guido van Rossumcacfc072002-05-24 19:01:59 +000042 for 'str' and 'unicode', and can be used instead of
43 types.StringTypes, e.g. to test whether something is "a string":
Neal Norwitz32a7e7f2002-05-31 19:58:02 +000044 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
Guido van Rossumcacfc072002-05-24 19:01:59 +000045 is an abstract base class and cannot be instantiated directly.
46
Fred Draked0ba6362002-05-02 21:28:26 +000047- Deprecated features of xrange objects have been removed as
48 promised. The start, stop, and step attributes and the tolist()
49 method no longer exist. xrange repetition and slicing have been
50 removed.
51
Guido van Rossum7dab2422002-04-26 19:40:56 +000052- New builtin function enumerate(x), from PEP 279. Example:
53 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
54 The argument can be an arbitrary iterable object.
55
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000056- The assert statement no longer tests __debug__ at runtime. This means
57 that assert statements cannot be disabled by assigning a false value
58 to __debug__.
59
Walter Dörwald068325e2002-04-15 13:36:47 +000060- A method zfill() was added to str and unicode, that fills a numeric
61 string to the left with zeros. For example,
62 "+123".zfill(6) -> "+00123".
63
Guido van Rossum862fe3c2002-04-15 12:36:47 +000064- Complex numbers supported divmod() and the // and % operators, but
65 these make no sense. Since this was documented, they're being
66 deprecated now.
67
Guido van Rossum26dd8302002-04-26 20:11:29 +000068- String and unicode methods lstrip(), rstrip() and strip() now take
69 an optional argument that specifies the characters to strip. For
70 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000071
Guido van Rossumc69343b2002-04-12 19:22:48 +000072- Added a new dict method pop(key). This removes and returns the
73 value corresponding to key. [SF patch #539949]
74
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000075- Changed new-style class instantiation so that when C's __new__
76 method returns something that's not a C instance, its __init__ is
77 not called. [SF bug #537450]
78
Guido van Rossum181e41a2002-04-06 00:23:25 +000079- Fixed super() to work correctly with class methods. [SF bug #535444]
80
Guido van Rossum47834462002-04-04 15:21:33 +000081- A new built-in type, bool, has been added, as well as built-in
82 names for its two values, True and False. Comparisons and sundry
83 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +000084 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +000085 is backward compatible.
86
Guido van Rossum95b62a62002-03-29 01:07:24 +000087- Fixed two bugs reported as SF #535905: under certain conditions,
88 deallocating a deeply nested structure could cause a segfault in the
89 garbage collector, due to interaction with the "trashcan" code;
90 access to the current frame during destruction of a local variable
91 could access a pointer to freed memory.
92
Neil Schemenauer9d50d132002-03-22 17:06:59 +000093- The optional object allocator has been enabled by default.
94
Guido van Rossum8c842552002-03-14 23:05:54 +000095- If you try to pickle an instance of a class that has __slots__ but
96 doesn't define or override __getstate__, a TypeError is now raised.
97 This is done by adding a bozo __getstate__ to the class that always
98 raises TypeError. (Before, this would appear to be pickled, but the
99 state of the slots would be lost.)
100
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000101- PyErr_Display will provide file and line information for all exceptions
102 that have an attribute print_file_and_line, not just SyntaxErrors.
103
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000104- The UTF-8 codec will now encode and decode Unicode surrogates
105 correctly and without raising exceptions for unpaired ones.
106
Neal Norwitz649b7592002-01-01 19:07:13 +0000107- file.xreadlines() now raises a ValueError if the file is closed:
108 Previously, an xreadlines object was returned which would raise
109 a ValueError when the xreadlines.next() method was called.
110
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000111- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000112 An exception will now be raised if more than one argument is used.
113
Tim Petersaf8446f2001-12-21 21:36:50 +0000114Extension modules
115
Tim Peters81b92512002-04-29 01:37:32 +0000116- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000117 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000118 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000119
Martin v. Löwis606edc12002-06-13 21:09:11 +0000120- posix.killpg, posix.mknod, and posix.getpgid have been added where
121 available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000122
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000123- The locale module now exposes the C library's gettext interface.
124
Tim Petersfbf74f22002-03-14 19:06:01 +0000125- A security hole ("double free") was found in zlib-1.1.3, a popular
126 third party compression library used by some Python modules. The
127 hole was quickly plugged in zlib-1.1.4, and the Windows build of
128 Python now ships with zlib-1.1.4.
129
Martin v. Löwis688357e2002-04-08 21:28:20 +0000130- pwd, grp, and resource return enhanced tuples now, with symbolic
131 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000132
Martin v. Löwis99866332002-03-01 10:27:01 +0000133- array.array is now a type object. A new format character
134 'u' indicates Py_UNICODE arrays. For those, .tounicode and
135 .fromunicode methods are available. Arrays now support __iadd__
136 and __imul__.
137
Neal Norwitze790eae2002-01-01 21:14:12 +0000138- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000139 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
140 is called.
141
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000142- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
143 been added where available.
144
Tim Petersaf8446f2001-12-21 21:36:50 +0000145Library
146
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000147- Some fixes in the copy module: when an object is copied through its
148 __reduce__ method, there was no check for a __setstate__ method on
149 the result [SF patch 565085]; deepcopy should treat instances of
150 custom metaclasses the same way it treats instances of type 'type'
151 [SF patch 560794].
152
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000153- Sockets now support timeout mode. After s.settimeout(T), where T is
154 a float expressing seconds, subsequent operations raise an exception
155 if they cannot be completed within T seconds. To disable timeout
156 mode, use s.settimeout(None).
157
158- getopt.gnu_getopt was added. This supports GNU-style option
159 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000160
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000161- Stop using strings for exceptions. String objects used for
162 exceptions are now classes deriving from Exception. The objects
163 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
164 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000165
Walter Dörwald474458d2002-06-04 15:16:29 +0000166- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
167 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
168 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
169 big endian systems were added to the codecs module. The old names
170 BOM32_* and BOM64_* were off by a factor of 2.
171
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000172- added degree/radian conversion functions to the math module.
173
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000174- ftplib.retrlines() now tests for callback is None rather than testing
175 for False. Was causing an error when given a callback object which
176 was callable but also returned len() as zero. The change may
177 create new breakage if the caller relied on the undocumented behavior
178 and called with callback set to [] or some other False value not
179 identical to None.
180
Tim Peters46c04e12002-05-05 20:40:00 +0000181- random.gauss() uses a piece of hidden state used by nothing else,
182 and the .seed() and .whseed() methods failed to reset it. In other
183 words, setting the seed didn't completely determine the sequence of
184 results produced by random.gauss(). It does now. Programs repeatedly
185 mixing calls to a seed method with calls to gauss() may see different
186 results now.
187
Fred Drake7f781c92002-05-01 20:33:53 +0000188- The pickle.Pickler class grew a clear_memo() method to mimic that
189 provided by cPickle.Pickler.
190
Tim Peters81b92512002-04-29 01:37:32 +0000191- difflib's SequenceMatcher class now does a dynamic analysis of
192 which elements are so frequent as to constitute noise. For
193 comparing files as sequences of lines, this generally works better
194 than the IS_LINE_JUNK function, and function ndiff's linejunk
195 argument defaults to None now as a result. A happy benefit is
196 that SequenceMatcher may run much faster now when applied
197 to large files with many duplicate lines (for example, C program
198 text with lots of repeated "}" and "return NULL;" lines).
199
Guido van Rossum256705b2002-04-23 13:29:43 +0000200- New Text.dump() method in Tkinter module.
201
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000202- New distutils commands for building packagers were added to
203 support pkgtool on Solaris and swinstall on HP-UX.
204
205- distutils now has a new abstract binary packager base class
206 command/bdist_packager, which simplifies writing packagers.
207 This will hopefully provide the missing bits to encourage
208 people to submit more packagers, e.g. for Debian, FreeBSD
209 and other systems.
210
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000211- The UTF-16, -LE and -BE now raise a NotImplementedError
212 for all calls to .readline(). Previously, they used to just
213 produce garbage or fail with an encoding error -- UTF-16 is
214 a 2-byte encoding and the C lib's line reading APIs don't
215 work well with these.
216
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000217- compileall now supports quiet operation.
218
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000219- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000220 connections.
221
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000222- socket module: the SSL support was broken out of the main
223 _socket module C helper and placed into a new _ssl helper
224 which now gets imported by socket.py if available and working.
225
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000226- encodings package: added aliases for all supported IANA character
227 sets
228
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000229- ftplib: to safeguard the user's privacy, anonymous login will use
230 "anonymous@" as default password, rather than the real user and host
231 name.
232
Fred Drake36736122002-01-10 13:50:31 +0000233- webbrowser: tightened up the command passed to os.system() so that
234 arbitrary shell code can't be executed because a bogus URL was
235 passed in.
236
Tim Peters11bd9942002-02-01 00:52:29 +0000237- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000238 gettext.find an optional all argument. Translations will now fallback
239 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000240
Martin v. Löwis9668b932002-01-12 11:27:42 +0000241- distutils bdist commands now offer a --skip-build option.
242
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000243- warnings.warn now accepts a Warning instance as first argument.
244
Fred Drakefed7e852002-04-04 19:36:15 +0000245- The xml.sax.expatreader.ExpatParser class will no longer create
246 circular references by using itself as the locator that gets passed
247 to the content handler implementation. [SF bug #535474]
248
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000249- The email.Parser.Parser class now properly parses strings regardless
250 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
251 or CRLF). Also, the Header class's constructor default arguments
252 has changed slightly so that an explicit maxlinelen value is always
253 honored.
254
Tim Petersaf8446f2001-12-21 21:36:50 +0000255Tools/Demos
256
Marc-André Lemburg46260092002-04-04 16:17:11 +0000257- freeze.py now produces binaries which can import shared modules,
258 unlike before when this failed due to missing symbol exports in
259 the generated binary.
260
Tim Petersaf8446f2001-12-21 21:36:50 +0000261Build
262
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000263- The configure option --without-doc-strings can be used to remove the
264 doc strings from the builtin functions and modules; this reduces the
265 size of the executable.
266
Tim Peters639295f2002-04-21 07:30:30 +0000267- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
268 say how or when to configure it, or how to turn it off.
269
Martin v. Löwis1142de32002-03-29 16:28:31 +0000270- On Unix, a shared libpython2.3.so can be created with --enable-shared.
271
Tim Peters8deda702002-03-30 10:06:07 +0000272- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
273 preprocessor symbols were eliminated. The internal decisions they
274 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000275
Fred Drake7d28b732002-05-02 21:17:00 +0000276- The tools used to build the documentation now work under Cygwin as
277 well as Unix.
278
Tim Petersaf8446f2001-12-21 21:36:50 +0000279C API
280
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000281- Added new macro PySequence_ITEM(o, i) that directly calls
282 sq_item without rechecking that o is a sequence and without
283 adjusting for negative indices.
284
Fred Draked0ba6362002-05-02 21:28:26 +0000285- PyRange_New() now raises ValueError if the fourth argument is not 1.
286 This is part of the removal of deprecated features of the xrange
287 object.
288
Guido van Rossum517c7d42002-04-26 02:49:14 +0000289- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
290 coercion if both arguments have the same type but this type has the
291 CHECKTYPES flag set. This is to better support proxies.
292
Neil Schemenauer9344b142002-04-12 23:00:08 +0000293- The type of tp_free has been changed from "void (*)(PyObject *)" to
294 "void (*)(void *)".
295
296- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
297
Guido van Rossum0986d822002-04-08 01:38:42 +0000298- A type can now inherit its metatype from its base type. Previously,
299 when PyType_Ready() was called, if ob_type was found to be NULL, it
300 was always set to &PyType_Type; now it is set to base->ob_type,
301 where base is tp_base, defaulting to &PyObject_Type.
302
303- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
304
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000305- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000306
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000307- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000308 without going through the buffer API.
309
Martin v. Löwis7198a522002-01-01 19:59:11 +0000310- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
311
Tim Peters10a3bb52001-12-25 19:07:38 +0000312- An old #define of ANY as void has been removed from pyport.h. This
313 hasn't been used since Python's pre-ANSI days, and the #define has
314 been marked as obsolete since then. SF bug 495548 says it created
315 conflicts with other packages, so keeping it around wasn't harmless.
316
Tim Petersaf8446f2001-12-21 21:36:50 +0000317- Because Python's magic number scheme broke on January 1st, we decided
318 to stop Python development. Thanks for all the fish!
319
Tim Petersfb05db22002-03-11 00:24:00 +0000320- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000321 scheme to a new one. See Python/import.c for details.
322
Tim Petersaf8446f2001-12-21 21:36:50 +0000323New platforms
324
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000325- AtheOS is now supported.
326
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000327- GNU/Hurd is now supported.
328
Tim Petersaf8446f2001-12-21 21:36:50 +0000329Tests
330
331Windows
332
Tim Peters08e72952002-04-16 20:48:01 +0000333- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
334 of that has been fixed in the installer (disabled Wise's "delete in-
335 use files" uninstall option).
336
Guido van Rossum181e41a2002-04-06 00:23:25 +0000337- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
338
Tim Peters33187922002-04-04 20:02:04 +0000339- The installer now installs Start menu shortcuts under (the local
340 equivalent of) "All Users" when doing an Admin install.
341
Tim Petersfb05db22002-03-11 00:24:00 +0000342- file.truncate([newsize]) now works on Windows for all newsize values.
343 It used to fail if newsize didn't fit in 32 bits, reflecting a
344 limitation of MS _chsize (which is no longer used).
345
Tim Petersab034fa2002-02-01 11:27:43 +0000346- os.waitpid() is now implemented for Windows, and can be used to block
347 until a specified process exits. This is similar to, but not exactly
348 the same as, os.waitpid() on POSIX systems. If you're waiting for
349 a specific process whose pid was obtained from one of the spawn()
350 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000351 See the docs for details. The docs were changed to clarify that
352 spawn functions return, and waitpid requires, a process handle on
353 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000354
Tim Peters11bd9942002-02-01 00:52:29 +0000355- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000356 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000357 to a nasty problem: before 2.3, if you got a temp file on Windows, it
358 got wrapped in an object whose close() method first closed the
359 underlying file, then deleted the file. This usually worked fine.
360 However, the spawn family of functions on Windows create (at a low C
361 level) the same set of open files in the spawned process Q as were
362 open in the spawning process P. If a temp file f was among them, then
363 doing f.close() in P first closed P's C-level file handle on f, but Q's
364 C-level file handle on f remained open, so the attempt in P to delete f
365 blew up with a "Permission denied" error (Windows doesn't allow
366 deleting open files). This was surprising, subtle, and difficult to
367 work around.
368
369- The os module now exports all the symbolic constants usable with the
370 low-level os.open() on Windows: the new constants in 2.3 are
371 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
372 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
373 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
374 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
375 (so specify both if you want both; note that neither is useful unless
376 specified with O_CREAT too).
377
Tim Petersaf8446f2001-12-21 21:36:50 +0000378Mac
379
380
Tim Peters909c0912001-12-14 23:16:18 +0000381What's New in Python 2.2 final?
382Release date: 21-Dec-2001
383===============================
384
385Type/class unification and new-style classes
386
Barry Warsaw52acb492001-12-21 20:04:22 +0000387- pickle.py, cPickle: allow pickling instances of new-style classes
388 with a custom metaclass.
389
Tim Peters909c0912001-12-14 23:16:18 +0000390Core and builtins
391
Barry Warsaw52acb492001-12-21 20:04:22 +0000392- weakref proxy object: when comparing, unwrap both arguments if both
393 are proxies.
394
Tim Peters909c0912001-12-14 23:16:18 +0000395Extension modules
396
Barry Warsaw52acb492001-12-21 20:04:22 +0000397- binascii.b2a_base64(): fix a potential buffer overrun when encoding
398 very short strings.
399
400- cPickle: the obscure "fast" mode was suspected of causing stack
401 overflows on the Mac. Hopefully fixed this by setting the recursion
402 limit much smaller. If the limit is too low (it only affects
403 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
404 when compiling cPickle.c (or in pyconfig.h).
405
Tim Peters909c0912001-12-14 23:16:18 +0000406Library
407
Barry Warsaw52acb492001-12-21 20:04:22 +0000408- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
409 close or delete time).
410
411- rfc822.py: fixed a bug where the address '<>' was converted to None
412 instead of an empty string (also fixes the email.Utils module).
413
414- xmlrpclib.py: version 1.0.0; uses precision for doubles.
415
416- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000417 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000418
Tim Peters909c0912001-12-14 23:16:18 +0000419Tools/Demos
420
421Build
422
423C API
424
425New platforms
426
427Tests
428
429Windows
430
Barry Warsaw52acb492001-12-21 20:04:22 +0000431- distutils package: fixed broken Windows installers (bdist_wininst).
432
433- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
434 instances are deleted at process exit time.
435
436- socket.py: prevent mysterious warnings when socket instances are
437 deleted at process exit time.
438
439- posixmodule.c: fix a Windows crash with stat() of a filename ending
440 in backslash.
441
Tim Peters909c0912001-12-14 23:16:18 +0000442Mac
443
Barry Warsaw52acb492001-12-21 20:04:22 +0000444- The Carbon toolbox modules have been upgraded to Universal Headers
445 3.4, and experimental CoreGraphics and CarbonEvents modules have
446 been added. All only for framework-enabled MacOSX.
447
Tim Peters909c0912001-12-14 23:16:18 +0000448
Tim Peters6272dfd2001-12-13 19:34:00 +0000449What's New in Python 2.2c1?
450Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000451===========================
452
453Type/class unification and new-style classes
454
Barry Warsaw06557452001-12-14 20:47:12 +0000455- Guido's tutorial introduction to the new type/class features has
456 been extensively updated. See
457
458 http://www.python.org/2.2/descrintro.html
459
460 That remains the primary documentation in this area.
461
Guido van Rossum33bab012001-12-05 22:45:48 +0000462- Fixed a leak: instance variables declared with __slots__ were never
463 deleted!
464
Guido van Rossum4b800852001-12-03 00:54:52 +0000465- The "delete attribute" method of descriptor objects is called
466 __delete__, not __del__. In previous releases, it was mistakenly
467 called __del__, which created an unfortunate overloading condition
468 with finalizers. (The "get attribute" and "set attribute" methods
469 are still called __get__ and __set__, respectively.)
470
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000471- Some subtle issues with the super built-in were fixed:
472
473 (a) When super itself is subclassed, its __get__ method would still
474 return an instance of the base class (i.e., of super).
475
476 (b) super(C, C()).__class__ would return C rather than super. This
477 is confusing. To fix this, I decided to change the semantics of
478 super so that it only applies to code attributes, not to data
479 attributes. After all, overriding data attributes is not
480 supported anyway.
481
482 (c) The __get__ method didn't check whether the argument was an
483 instance of the type used in creation of the super instance.
484
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000485- Previously, hash() of an instance of a subclass of a mutable type
486 (list or dictionary) would return some value, rather than raising
487 TypeError. This has been fixed. Also, directly calling
488 dict.__hash__ and list.__hash__ now raises the same TypeError
489 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000490
Guido van Rossumd331cb52001-12-05 19:46:42 +0000491- New-style objects now support deleting their __dict__. This is for
492 all intents and purposes equivalent to assigning a brand new empty
493 dictionary, but saves space if the object is not used further.
494
Tim Petersb3c9af12001-11-17 00:21:57 +0000495Core and builtins
496
Tim Peters3caca232001-12-06 06:23:26 +0000497- -Qnew now works as documented in PEP 238: when -Qnew is passed on
498 the command line, all occurrences of "/" use true division instead
499 of classic division. See the PEP for details. Note that "all"
500 means all instances in library and 3rd-party modules, as well as in
501 your own code. As the PEP says, -Qnew is intended for use only in
502 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000503 Note that test_coercion.py in the standard Python test suite fails
504 under -Qnew; this is expected, and won't be repaired until true
505 division becomes the default (in the meantime, test_coercion is
506 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000507
Fred Drake6c01e252001-12-14 17:08:12 +0000508- complex() now only allows the first argument to be a string
509 argument, and raises TypeError if either the second arg is a string
510 or if the second arg is specified when the first is a string.
511
Tim Petersb3c9af12001-11-17 00:21:57 +0000512Extension modules
513
Martin v. Löwis560da622001-11-24 09:24:51 +0000514- gc.get_referents was renamed to gc.get_referrers.
515
Tim Petersb3c9af12001-11-17 00:21:57 +0000516Library
517
Tim Peters25059d32001-12-07 20:35:43 +0000518- Functions in the os.spawn() family now release the global interpreter
519 lock around calling the platform spawn. They should always have done
520 this, but did not before 2.2c1. Multithreaded programs calling
521 an os.spawn function with P_WAIT will no longer block all Python threads
522 until the spawned program completes. It's possible that some programs
523 relies on blocking, although more likely by accident than by design.
524
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000525- webbrowser defaults to netscape.exe on OS/2 now.
526
Martin v. Löwis652e1912001-11-25 14:50:56 +0000527- Tix.ResizeHandle exposes detach_widget, hide, and show.
528
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000529- The charset alias windows_1252 has been added.
530
Barry Warsaw06557452001-12-14 20:47:12 +0000531- types.StringTypes is a tuple containing the defined string types;
532 usually this will be (str, unicode), but if Python was compiled
533 without Unicode support it will be just (str,).
534
535- The pulldom and minidom modules were synchronized to PyXML.
536
Tim Petersb3c9af12001-11-17 00:21:57 +0000537Tools/Demos
538
Barry Warsaw06557452001-12-14 20:47:12 +0000539- A new script called Tools/scripts/google.py was added, which fires
540 off a search on Google.
541
Tim Petersb3c9af12001-11-17 00:21:57 +0000542Build
543
Barry Warsaw06557452001-12-14 20:47:12 +0000544- Note that release builds of Python should arrange to define the
545 preprocessor symbol NDEBUG on the command line (or equivalent).
546 In the 2.2 pre-release series we tried to define this by magic in
547 Python.h instead, but it proved to cause problems for extension
548 authors. The Unix, Windows and Mac builds now all define NDEBUG in
549 release builds via cmdline (or equivalent) instead. Ports to
550 other platforms should do likewise.
551
Jack Jansen1999ef42001-12-06 21:47:20 +0000552- It is no longer necessary to use --with-suffix when building on a
553 case-insensitive file system (such as Mac OS X HFS+). In the build
554 directory an extension is used, but not in the installed python.
555
Tim Petersb3c9af12001-11-17 00:21:57 +0000556C API
557
Tim Petersf582b822001-12-11 18:51:08 +0000558- New function PyDict_MergeFromSeq2() exposes the builtin dict
559 constructor's logic for updating a dictionary from an iterable object
560 producing key-value pairs.
561
Tim Peterscffed4b2001-11-29 03:26:37 +0000562- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000563 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000564 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
565 dump core in some bad cases. This has been repaired. As a result,
566 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
567 previously went unchallenged.
568
Tim Petersb3c9af12001-11-17 00:21:57 +0000569New platforms
570
571Tests
572
573Windows
574
575Mac
576
Jack Jansenffa260f2001-12-06 21:14:00 +0000577- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
578 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000579
Barry Warsaw06557452001-12-14 20:47:12 +0000580- Changed logic for finding python home in Mac OS X framework Pythons.
581 Now sys.executable points to the executable again, in stead of to
582 the shared library. The latter is used only for locating the python
583 home.
584
585
Tim Peters84362bc2001-10-19 17:55:30 +0000586What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000587Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000588===========================
589
590Type/class unification and new-style classes
591
Guido van Rossum3d27df02001-11-15 20:27:54 +0000592- Multiple inheritance mixing new-style and classic classes in the
593 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000594
595 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000596 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000597
598 The MRO (method resolution order) for each base class is respected
599 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000600 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000601 This needs to be documented.
602
Tim Petersa427a2b2001-10-29 22:25:45 +0000603- The new builtin dictionary() constructor, and dictionary type, have
604 been renamed to dict. This reflects a decade of common usage.
605
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000606- dict() now accepts an iterable object producing 2-sequences. For
607 example, dict(d.items()) == d for any dictionary d. The argument,
608 and the elements of the argument, can be any iterable objects.
609
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000610- New-style classes can now have a __del__ method, which is called
611 when the instance is deleted (just like for classic classes).
612
Guido van Rossum12d955c2001-10-26 14:56:06 +0000613- Assignment to object.__dict__ is now possible, for objects that are
614 instances of new-style classes that have a __dict__ (unless the base
615 class forbids it).
616
Guido van Rossumc8e56452001-10-22 00:43:43 +0000617- Methods of built-in types now properly check for keyword arguments
618 (formerly these were silently ignored). The only built-in methods
619 that take keyword arguments are __call__, __init__ and __new__.
620
Guido van Rossum86443212001-10-27 22:28:54 +0000621- The socket function has been converted to a type; see below.
622
Tim Peters84362bc2001-10-19 17:55:30 +0000623Core and builtins
624
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000625- Assignment to __debug__ raises SyntaxError at compile-time. This
626 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000627 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000628
Guido van Rossum12d955c2001-10-26 14:56:06 +0000629- Clarified the error messages for unsupported operands to an operator
630 (like 1 + '').
631
Tim Peters84362bc2001-10-19 17:55:30 +0000632Extension modules
633
Tim Peters5ebfd362001-11-13 23:11:19 +0000634- mmap has a new keyword argument, "access", allowing a uniform way for
635 both Windows and Unix users to create read-only, write-through and
636 copy-on-write memory mappings. This was previously possible only on
637 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000638 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000639 platforms. Thanks to Jay T Miller for repairing this!
640
Tim Peters169ded02001-11-03 19:57:21 +0000641- By default, the gc.garbage list now contains only those instances in
642 unreachable cycles that have __del__ methods; in 2.1 it contained all
643 instances in unreachable cycles. "Instances" here has been generalized
644 to include instances of both new-style and old-style classes.
645
Guido van Rossum12d955c2001-10-26 14:56:06 +0000646- The socket module defines a new method for socket objects,
647 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000648 send() until all data has been sent. Also, the socket function has
649 been converted to a subclassable type, like list and tuple (etc.)
650 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000651
652- Various bugfixes to the curses module. There is now a test suite
653 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000654
Guido van Rossum692adf12001-10-30 03:03:03 +0000655- binascii.b2a_base64 no longer places an arbitrary restriction of 57
656 bytes on its input.
657
Tim Peters84362bc2001-10-19 17:55:30 +0000658Library
659
Tim Peters5ebfd362001-11-13 23:11:19 +0000660- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000661 convenience function.
662
Tim Peters75335872001-11-03 19:35:43 +0000663- Symbolic group names in regular expressions must be unique. For
664 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
665 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000666 Python 2.2 detects this error at regexp compilation time;
667 previously, the error went undetected, and results were
668 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
669 pattern.subn() methods have been rewritten in C. Also, an
670 experimental function/method finditer() has been added, which works
671 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000672
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000673- Tix exposes more commands through the classes DirSelectBox,
674 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
675 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
676 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
677
Tim Peters98791af2001-10-23 01:59:54 +0000678- Traceback objects are now scanned by cyclic garbage collection, so
679 cycles created by casual use of sys.exc_info() no longer cause
680 permanent memory leaks (provided garbage collection is enabled).
681
Guido van Rossum49192142001-10-24 20:51:44 +0000682- os.extsep -- a new variable needed by the RISCOS support. It is the
683 separator used by extensions, and is '.' on all platforms except
684 RISCOS, where it is '/'. There is no need to use this variable
685 unless you have a masochistic desire to port your code to RISCOS.
686
Barry Warsaw012852b2001-11-16 16:17:27 +0000687- mimetypes.py has optional support for non-standard, but commonly
688 found types. guess_type() and guess_extension() now accept an
689 optional `strict' flag, defaulting to true, which controls whether
690 recognize non-standard types or not. A few non-standard types we
691 know about have been added. Also, when run as a script, there are
692 new -l and -e options.
693
694- statcache is now deprecated.
695
696- email.Utils.formatdate() now produces the preferred RFC 2822 style
697 dates with numeric timezones (it used to produce obsolete dates
698 hard coded to "GMT" timezone). An optional `localtime' flag is
699 added to produce dates in the local timezone, with daylight savings
700 time properly taken into account.
701
702- In pickle and cPickle, instead of masking errors in load() by
703 transforming them into SystemError, we let the original exception
704 propagate out. Also, implement support for __safe_for_unpickling__
705 in pickle, as it already was supported in cPickle.
706
Tim Peters84362bc2001-10-19 17:55:30 +0000707Tools/Demos
708
709Build
710
Barry Warsaw012852b2001-11-16 16:17:27 +0000711- The dbm module is built using libdb1 if available. The bsddb module
712 is built with libdb3 if available.
713
714- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
715
Tim Peters84362bc2001-10-19 17:55:30 +0000716C API
717
Tim Peters1fc240e2001-10-26 05:06:50 +0000718- New function PySequence_Fast_GET_SIZE() returns the size of a non-
719 NULL result from PySequence_Fast(), more quickly than calling
720 PySequence_Size().
721
Barry Warsaw012852b2001-11-16 16:17:27 +0000722- New argument unpacking function PyArg_UnpackTuple() added.
723
724- New functions PyObject_CallFunctionObjArgs() and
725 PyObject_CallMethodObjArgs() have been added to make it more
726 convenient and efficient to call functions and methods from C.
727
728- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
729 possible that this will propagate errors it didn't before.
730
731- New function PyObject_CheckReadBuffer(), which returns true if its
732 argument supports the single-segment readable buffer interface.
733
Tim Peters84362bc2001-10-19 17:55:30 +0000734New platforms
735
Guido van Rossum86443212001-10-27 22:28:54 +0000736- We've finally confirmed that this release builds on HP-UX 11.00,
737 *with* threads, and passes the test suite.
738
Tim Peters7a33d8b2001-11-05 02:51:07 +0000739- Thanks to a series of patches from Michael Muller, Python may build
740 again under OS/2 Visual Age C++.
741
Guido van Rossum49192142001-10-24 20:51:44 +0000742- Updated RISCOS port by Dietmar Schwertberger.
743
Tim Peters84362bc2001-10-19 17:55:30 +0000744Tests
745
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000746- Added a test script for the curses module. It isn't run automatically;
747 regrtest.py must be run with '-u curses' to enable it.
748
Tim Peters84362bc2001-10-19 17:55:30 +0000749Windows
750
Barry Warsaw012852b2001-11-16 16:17:27 +0000751Mac
752
753- PythonScript has been moved to unsupported and is slated to be
754 removed completely in the next release.
755
756- It should now be possible to build applets that work on both OS9 and
757 OSX.
758
759- The core is now linked with CoreServices not Carbon; as a side
760 result, default 8bit encoding on OSX is now ASCII.
761
762- Python should now build on OSX 10.1.1
763
Tim Peters84362bc2001-10-19 17:55:30 +0000764
Tim Petersabf925f2001-09-28 21:53:42 +0000765What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000766Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000767===========================
768
769Type/class unification and new-style classes
770
Guido van Rossum687ae002001-10-15 22:03:32 +0000771- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000772 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000773 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000774 remains: the __dict__ of a new-style class is a read-only proxy; you
775 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000776 __defined__ attribute of new-style types no longer exists, for lack
777 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000778 future a __cache__ may be resurrected with a similar function, if I
779 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000780
Tim Peters1c9ca872001-10-04 06:43:12 +0000781- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
782 always returned None, even when there was a class docstring).
783
784- doctest now finds and runs docstrings attached to new-style classes,
785 class methods, static methods, and properties.
786
Guido van Rossum9074ef62001-10-16 21:34:49 +0000787Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000788
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000789- A very subtle syntactical pitfall in list comprehensions was fixed.
790 For example: [a+b for a in 'abc', for b in 'def']. The comma in
791 this example is a mistake. Previously, this would silently let 'a'
792 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
793 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
794 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
795 Note that [a for a in <singleton>] is a convoluted way to say
796 [<singleton>] anyway, so it's not like any expressiveness is lost.
797
Guido van Rossum9074ef62001-10-16 21:34:49 +0000798- getattr(obj, name, default) now only catches AttributeError, as
799 documented, rather than returning the default value for all
800 exceptions (which could mask bugs in a __getattr__ hook, for
801 example).
802
Fred Drakecb7a6b52001-10-22 18:41:51 +0000803- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000804 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000805 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000806 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000807
Guido van Rossum1c486092001-10-19 02:05:35 +0000808- unicode(obj) now behaves more like str(obj), accepting arbitrary
809 objects, and calling a __unicode__ method if it exists.
810 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000811 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000812
Barry Warsawf6fb1712001-10-19 05:35:40 +0000813- isinstance() now allows any object as the first argument and a
814 class, a type or something with a __bases__ tuple attribute for the
815 second argument. The second argument may also be a tuple of a
816 class, type, or something with __bases__, in which case isinstance()
817 will return true if the first argument is an instance of any of the
818 things contained in the second argument tuple. E.g.
819
820 isinstance(x, (A, B))
821
822 returns true if x is an instance of A or B.
823
Guido van Rossum9074ef62001-10-16 21:34:49 +0000824Extension modules
825
826- thread.start_new_thread() now returns the thread ID (previously None).
827
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000828- binascii has now two quopri support functions, a2b_qp and b2a_qp.
829
Guido van Rossumc524d952001-10-19 01:31:59 +0000830- readline now supports setting the startup_hook and the
831 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000832
Guido van Rossumc524d952001-10-19 01:31:59 +0000833- os and posix supports chroot(), setgroups() and unsetenv() where
834 available. The stat(), fstat(), statvfs() and fstatvfs() functions
835 now return "pseudo-sequences" -- the various fields can now be
836 accessed as attributes (e.g. os.stat("/").st_mtime) but for
837 backwards compatibility they also behave as a fixed-length sequence.
838 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000839 attributes.
840
841- time: localtime(), gmtime() and strptime() now return a
842 pseudo-sequence similar to the os.stat() return value, with
843 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000844
Guido van Rossum9074ef62001-10-16 21:34:49 +0000845- Decompression objects in the zlib module now accept an optional
846 second parameter to decompress() that specifies the maximum amount
847 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000848
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000849- optional SSL support in the socket module now exports OpenSSL
850 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
851 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000852 automatically seed its PRNG. Also, the keyfile and certfile
853 arguments to socket.ssl() are now optional.
854
855- posixmodule (and by extension, the os module on POSIX platforms) now
856 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000857
Guido van Rossum9074ef62001-10-16 21:34:49 +0000858Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000859
Tim Peters7402f792001-10-02 03:53:41 +0000860- doctest now excludes functions and classes not defined by the module
861 being tested, thanks to Tim Hochberg.
862
Fred Drakecb7a6b52001-10-22 18:41:51 +0000863- HotShot, a new profiler implemented using a C-based callback, has
864 been added. This substantially reduces the overhead of profiling,
865 but it is still quite preliminary. Support modules and
866 documentation will be added in upcoming releases (before 2.2 final).
867
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000868- profile now produces correct output in situations where an exception
869 raised in Python is cleared by C code (e.g. hasattr()). This used
870 to cause wrong output, including spurious claims of recursive
871 functions and attribution of time spent to the wrong function.
872
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000873 The code and documentation for the derived OldProfile and HotProfile
874 profiling classes was removed. The code hasn't worked for years (if
875 you tried to use them, they raised exceptions). OldProfile
876 intended to reproduce the behavior of the profiler Python used more
877 than 7 years ago, and isn't interesting anymore. HotProfile intended
878 to provide a faster profiler (but producing less information), and
879 that's a worthy goal we intend to meet via a different approach (but
880 without losing information).
881
Tim Peterscce092d2001-10-09 05:31:56 +0000882- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000883 a much better system-specific calibration constant. The constant can
884 now be specified in an instance constructor, or as a Profile class or
885 instance variable, instead of by editing profile.py's source code.
886 Calibration must still be done manually (see the docs for the profile
887 module).
888
889 Note that Profile.calibrate() must be overriden by subclasses.
890 Improving the accuracy required exploiting detailed knowledge of
891 profiler internals; the earlier method abstracted away the details
892 and measured a simplified model instead, but consequently computed
893 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000894
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000895- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000896 which indicates whether output is intended for the header 'Q'
897 encoding.
898
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000899- The SocketServer.ThreadingMixIn class now closes the request after
900 finish_request() returns. (Not when it errors out though.)
901
Barry Warsawf6fb1712001-10-19 05:35:40 +0000902- The nntplib module's NNTP.body() method has grown a `file' argument
903 to allow saving the message body to a file.
904
905- The email package has added a class email.Parser.HeaderParser which
906 only parses headers and does not recurse into the message's body.
907 Also, the module/class MIMEAudio has been added for representing
908 audio data (contributed by Anthony Baxter).
909
910- ftplib should be able to handle files > 2GB.
911
912- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
913 ON, and OFF.
914
Fred Drakecb7a6b52001-10-22 18:41:51 +0000915- xml.dom.minidom NodeList objects now support the length attribute
916 and item() method as required by the DOM specifications.
917
Guido van Rossumed554f62001-10-02 23:15:37 +0000918Tools/Demos
919
920- Demo/dns was removed. It no longer serves any purpose; a package
921 derived from it is now maintained by Anthony Baxter, see
922 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000923
Barry Warsawf6fb1712001-10-19 05:35:40 +0000924- The freeze tool has been made more robust, and two new options have
925 been added: -X and -E.
926
Tim Petersabf925f2001-09-28 21:53:42 +0000927Build
928
Barry Warsawf6fb1712001-10-19 05:35:40 +0000929- configure will use CXX in LINKCC if CXX is used to build main() and
930 the system requires to link a C++ main using the C++ compiler.
931
Tim Petersabf925f2001-09-28 21:53:42 +0000932C API
933
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000934- The documentation for the tp_compare slot is updated to require that
935 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
936 not correct. This is not yet enforced but will be enforced in
937 Python 2.3; even later, we may use -2 to indicate errors and +2 for
938 "NotImplemented". Right now, -1 should be used for an error return.
939
Tim Petersd38b1c72001-09-30 05:09:37 +0000940- PyLong_AsLongLong() now accepts int (as well as long) arguments.
941 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
942 as long) arguments.
943
Guido van Rossum3c288632001-10-16 21:13:49 +0000944- PyThread_start_new_thread() now returns a long int giving the thread
945 ID, if one can be calculated; it returns -1 for error, 0 if no
946 thread ID is calculated (this is an incompatible change, but only
947 the thread module used this API). This code has only really been
948 tested on Linux and Windows; other platforms please beware (and
949 report any bugs or strange behavior).
950
Guido van Rossum1c486092001-10-19 02:05:35 +0000951- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
952 input.
953
Tim Petersabf925f2001-09-28 21:53:42 +0000954New platforms
955
956Tests
957
958Windows
959
Tim Peters04cf1d32001-10-09 22:39:40 +0000960- Installer: If you install IDLE, and don't disable file-extension
961 registration, a new "Edit with IDLE" context (right-click) menu entry
962 is created for .py and .pyw files.
963
Tim Peters1ce3cf72001-10-01 17:58:40 +0000964- The signal module now supports SIGBREAK on Windows, thanks to Steven
965 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
966 action remains to call Win32 ExitProcess(). This can be changed via
967 signal.signal(). For example:
968
969 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
970 # (SIGINT) behavior.
971 import signal
972 signal.signal(signal.SIGBREAK,
973 signal.default_int_handler)
974
975 try:
976 while 1:
977 pass
978 except KeyboardInterrupt:
979 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
980 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
981 # program without the possibility for any Python-level cleanup).
982 print "Clean exit"
983
Tim Petersabf925f2001-09-28 21:53:42 +0000984
Tim Petersb07352e2001-09-08 01:25:47 +0000985What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000986Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000987===========================
988
Guido van Rossum808eea72001-09-25 04:15:41 +0000989Type/class unification and new-style classes
990
991- pydoc and inspect are now aware of new-style classes;
992 e.g. help(list) at the interactive prompt now shows proper
993 documentation for all operations on list objects.
994
995- Applications using Jim Fulton's ExtensionClass module can now safely
996 be used with Python 2.2. In particular, Zope 2.4.1 now works with
997 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
998 examples also work again. It is hoped that Gtk and Boost also work
999 with 2.2a4 and beyond. (If you can confirm this, please write
1000 webmaster@python.org; if there are still problems, please open a bug
1001 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001002
Tim Peters66c1a522001-09-24 21:17:50 +00001003- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001004 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001005 in the constructed property object. fget, fset and fdel weren't
1006 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1007 associate a docstring with a property.
1008
Guido van Rossum808eea72001-09-25 04:15:41 +00001009- Comparison overloading is now more completely implemented. For
1010 example, a str subclass instance can properly be compared to a str
1011 instance, and it can properly overload comparison. Ditto for most
1012 other built-in object types.
1013
1014- The repr() of new-style classes has changed; instead of <type
1015 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1016 *except* for built-in types, which are still rendered as <type
1017 'Foo'> (to avoid upsetting existing code that might parse or
1018 otherwise rely on repr() of certain type objects).
1019
1020- The repr() of new-style objects is now always <Foo object at XXX>;
1021 previously, it was sometimes <Foo instance at XXX>.
1022
1023- For new-style classes, what was previously called __getattr__ is now
1024 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001025 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001026 one in classic classes is defined which is called only if regular
1027 attribute access raises AttributeError; to catch *all* attribute
1028 access, you can use __getattribute__ (for new-style classes). If
1029 both are defined, __getattribute__ is called first, and if it raises
1030 AttributeError, __getattr__ is called.
1031
1032- The __class__ attribute of new-style objects can be assigned to.
1033 The new class must have the same C-level object layout as the old
1034 class.
1035
1036- The builtin file type can be subclassed now. In the usual pattern,
1037 "file" is the name of the builtin type, and file() is a new builtin
1038 constructor, with the same signature as the builtin open() function.
1039 file() is now the preferred way to open a file.
1040
1041- Previously, __new__ would only see sequential arguments passed to
1042 the type in a constructor call; __init__ would see both sequential
1043 and keyword arguments. This made no sense whatsoever any more, so
1044 now both __new__ and __init__ see all arguments.
1045
1046- Previously, hash() applied to an instance of a subclass of str or
1047 unicode always returned 0. This has been repaired.
1048
1049- Previously, an operation on an instance of a subclass of an
1050 immutable type (int, long, float, complex, tuple, str, unicode),
1051 where the subtype didn't override the operation (and so the
1052 operation was handled by the builtin type), could return that
1053 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001054 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001055 with the same value as s.
1056
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001057- Provisional support for pickling new-style objects has been added.
1058
Guido van Rossum808eea72001-09-25 04:15:41 +00001059Core
1060
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001061- file.writelines() now accepts any iterable object producing strings.
1062
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001063- PyUnicode_FromEncodedObject() now works very much like
1064 PyObject_Str(obj) in that it tries to use __str__/tp_str
1065 on the object if the object is not a string or buffer. This
1066 makes unicode() behave like str() when applied to non-string/buffer
1067 objects.
1068
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001069- PyFile_WriteObject now passes Unicode objects to the file's write
1070 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001071 of a print statement must support Unicode objects, i.e. they must
1072 at least convert them into ASCII strings.
1073
Guido van Rossum624c8af2001-09-18 15:21:04 +00001074- Thread scheduling on Solaris should be improved; it is no longer
1075 necessary to insert a small sleep at the start of a thread in order
1076 to let other runnable threads be scheduled.
1077
Tim Petersb07352e2001-09-08 01:25:47 +00001078Library
1079
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001080- StringIO.StringIO instances and cStringIO.StringIO instances support
1081 read character buffer compatible objects for their .write() methods.
1082 These objects are converted to strings and then handled as such
1083 by the instances.
1084
Barry Warsaw2f600732001-09-24 04:28:10 +00001085- The "email" package has been added. This is basically a port of the
1086 mimelib package <http://sf.net/projects/mimelib> with API changes
1087 and some implementations updated to use iterators and generators.
1088
Tim Peters8a9c2842001-09-22 21:30:22 +00001089- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1090 restores the ability of Tools/scripts/ndiff.py to start producing output
1091 before the entire comparison is complete.
1092
Barry Warsaw58b072d2001-09-22 04:44:21 +00001093- StringIO.StringIO instances and cStringIO.StringIO instances support
1094 iteration just like file objects (i.e. their .readline() method is
1095 called for each iteration until it returns an empty string).
1096
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001097- The codecs module has grown four new helper APIs to access
1098 builtin codecs: getencoder(), getdecoder(), getreader(),
1099 getwriter().
1100
Guido van Rossum624c8af2001-09-18 15:21:04 +00001101- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1102 simplifies writing XML RPC servers.
1103
Barry Warsaw647d5e82001-09-28 17:01:02 +00001104- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001105 after interpretation of symbolic links. On non-Unix systems, this
1106 is an alias for os.path.abspath().
1107
Tim Peters16a77ad2001-09-08 04:00:12 +00001108- operator.indexOf() (PySequence_Index() in the C API) now works with any
1109 iterable object.
1110
Guido van Rossum624c8af2001-09-18 15:21:04 +00001111- smtplib now supports various authentication and security features of
1112 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001113
Guido van Rossum624c8af2001-09-18 15:21:04 +00001114- hmac: a new module implementing keyed hashing for message
1115 authentication.
1116
1117- mimetypes now recognizes more extensions and file types. At the
1118 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001119
Guido van Rossum624c8af2001-09-18 15:21:04 +00001120- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001121 Python 2.2 bytecode generation. It has also been promoted from a
1122 Tool to a standard library package. (Tools/compiler still exists as
1123 a sample driver.)
1124
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001125Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001126
Tim Petersb07352e2001-09-08 01:25:47 +00001127Build
1128
Guido van Rossum624c8af2001-09-18 15:21:04 +00001129- Large file support (LFS) is now automatic when the platform supports
1130 it; no more manual configuration tweaks are needed. On Linux, at
1131 least, it's possible to have a system whose C library supports large
1132 files but whose kernel doesn't; in this case, large file support is
1133 still enabled but doesn't do you any good unless you upgrade your
1134 kernel or share your Python executable with another system whose
1135 kernel has large file support.
1136
1137- The configure script now supplies plausible defaults in a
1138 cross-compilation environment. This doesn't mean that the supplied
1139 values are always correct, or that cross-compilation now works
1140 flawlessly -- but it's a first step (and it shuts up most of
1141 autoconf's warnings about AC_TRY_RUN).
1142
1143- The Unix build is now a bit less chatty, courtesy of the parser
1144 generator. The build is completely silent (except for errors) when
1145 using "make -s", thanks to a -q option to setup.py.
1146
Tim Petersb07352e2001-09-08 01:25:47 +00001147C API
1148
Guido van Rossum624c8af2001-09-18 15:21:04 +00001149- The "structmember" API now supports some new flag bits to deny read
1150 and/or write access to attributes in restricted execution mode.
1151
Tim Petersb07352e2001-09-08 01:25:47 +00001152New platforms
1153
Guido van Rossum624c8af2001-09-18 15:21:04 +00001154- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1155 (http://familiar.handhelds.org).
1156
Tim Petersb07352e2001-09-08 01:25:47 +00001157Tests
1158
Tim Peters8a9c2842001-09-22 21:30:22 +00001159- The "classic" standard tests, which work by comparing stdout to
1160 an expected-output file under Lib/test/output/, no longer stop at
1161 the first mismatch. Instead the test is run to completion, and a
1162 variant of ndiff-style comparison is used to report all differences.
1163 This is much easier to understand than the previous style of reporting.
1164
1165- The unittest-based standard tests now use regrtest's test_main()
1166 convention, instead of running as a side-effect of merely being
1167 imported. This allows these tests to be run in more natural and
1168 flexible ways as unittests, outside the regrtest framework.
1169
1170- regrtest.py is much better integrated with unittest and doctest now,
1171 especially in regard to reporting errors.
1172
Tim Petersb07352e2001-09-08 01:25:47 +00001173Windows
1174
Guido van Rossum624c8af2001-09-18 15:21:04 +00001175- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001176 that support it (NTFS under Windows 2000). See "What's New in
1177 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001178
Tim Petersb07352e2001-09-08 01:25:47 +00001179
Tim Petersedc99312001-08-22 21:36:50 +00001180What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001181Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001182===========================
1183
1184Core
1185
Tim Peters9fffa3e2001-09-04 05:14:19 +00001186- Conversion of long to float now raises OverflowError if the long is too
1187 big to represent as a C double.
1188
Tim Peters32f453e2001-09-03 08:35:41 +00001189- The 3-argument builtin pow() no longer allows a third non-None argument
1190 if either of the first two arguments is a float, or if both are of
1191 integer types and the second argument is negative (in which latter case
1192 the arguments are converted to float, so this is really the same
1193 restriction).
1194
Tim Peters5d2b77c2001-09-03 05:47:38 +00001195- The builtin dir() now returns more information, and sometimes much
1196 more, generally naming all attributes of an object, and all attributes
1197 reachable from the object via its class, and from its class's base
1198 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1199 an empty list. In 2.2a3,
1200
1201 >>> dir([])
1202 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1203 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1204 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1205 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1206 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1207 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1208 'reverse', 'sort']
1209
1210 dir(module) continues to return only the module's attributes, though.
1211
Tim Petersbdee63f2001-09-02 03:40:59 +00001212- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001213 than raising OverflowError. This is a partial implementation of PEP
1214 237. You can use -Wdefault::OverflowWarning to enable a warning for
1215 this situation, and -Werror::OverflowWarning to revert to the old
1216 OverflowError exception.
1217
Guido van Rossum61c345f2001-09-04 03:26:15 +00001218- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001219 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001220 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1221 -Qold, meaning the / operator has its classic meaning and no
1222 warnings are issued. Using -Qwarn issues a run-time warning about
1223 all uses of classic division for int and long arguments; -Qwarnall
1224 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001225 (for use with fixdiv.py).
1226 [Note: the remainder of this paragraph (preserved below) became
1227 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1228 <obsolete>
1229 Using -Qnew is questionable; it turns on new division by default, but
1230 only in the __main__ module. You can usefully combine -Qwarn or
1231 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1232 warns about classic division everywhere else.
1233 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001234
Tim Petersbdee63f2001-09-02 03:40:59 +00001235- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001236 long, float, str, unicode, and tuple. (The types complex, list and
1237 dictionary can also be subclassed; this was introduced earlier.)
1238 Note that restrictions apply when subclassing immutable built-in
1239 types: you can only affect the value of the instance by overloading
1240 __new__. You can add mutable attributes, and the subclass instances
1241 will have a __dict__ attribute, but you cannot change the "value"
1242 (as implemented by the base class) of an immutable subclass instance
1243 once it is created.
1244
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001245- The dictionary constructor now takes an optional argument, a
1246 mapping-like object, and initializes the dictionary from its
1247 (key, value) pairs.
1248
Tim Petersbdee63f2001-09-02 03:40:59 +00001249- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001250 "cooperative super calls" in a multiple inheritance setting. For an
1251 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1252
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001253- A new built-in type, property, has been added. This enables the
1254 creation of "properties". These are attributes implemented by
1255 getter and setter functions (or only one of these for read-only or
1256 write-only attributes), without the need to override __getattr__.
1257 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001258
Tim Petersbdee63f2001-09-02 03:40:59 +00001259- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001260 liberalized, to allow leading zeroes. Examples of literals now
1261 legal that were SyntaxErrors before:
1262
1263 00.0 0e3 0100j 07.5 00000000000000000008.
1264
Tim Petersbdee63f2001-09-02 03:40:59 +00001265- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001266 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1267
Tim Petersedc99312001-08-22 21:36:50 +00001268Library
1269
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001270- telnetlib includes symbolic names for the options, and support for
1271 setting an option negotiation callback.
1272
Tim Petersa40c7932001-09-05 22:36:56 +00001273- The new C standard no longer requires that math libraries set errno to
1274 ERANGE on overflow. For platform libraries that exploit this new
1275 freedom, Python's overflow-checking was wholly broken. A new overflow-
1276 checking scheme attempts to repair that, but may not be reliable on all
1277 platforms (C doesn't seem to provide anything both useful and portable
1278 in this area anymore).
1279
Martin v. Löwis44f86962001-09-05 13:44:54 +00001280- Asynchronous timeout actions are available through the new class
1281 threading.Timer.
1282
Tim Peters78526162001-09-05 00:53:45 +00001283- math.log and math.log10 now return sensible results for even huge
1284 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1285
Tim Petersbdee63f2001-09-02 03:40:59 +00001286- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001287 currently held. See the docs for the imp module.
1288
Tim Petersbdee63f2001-09-02 03:40:59 +00001289- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001290 dumps containing ints written on platforms where Python ints are 8 bytes.
1291 When read on a box where Python ints are 4 bytes, such values are
1292 converted to Python longs.
1293
Tim Petersbdee63f2001-09-02 03:40:59 +00001294- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001295 code objects is no longer allowed. This plugs a security hole.
1296
Steve Purcell6091cd62001-09-06 16:05:17 +00001297- unittest.TestResult instances no longer store references to tracebacks
1298 generated by test failures. This prevents unexpected dangling references
1299 to objects that should be garbage collected between tests.
1300
Tim Petersedc99312001-08-22 21:36:50 +00001301Tools
1302
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001303- Tools/scripts/fixdiv.py has been added which can be used to fix
1304 division operators as per PEP 238.
1305
Tim Petersedc99312001-08-22 21:36:50 +00001306Build
1307
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001308- If you are an adventurous person using Mac OS X you may want to look at
1309 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1310 application, which can be used for experimenting with Carbon or Cocoa.
1311 Discussion of this on pythonmac-sig, please.
1312
Tim Peters7eea37e2001-09-04 22:08:56 +00001313C API
1314
1315- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001316
Tim Peters9fffa3e2001-09-04 05:14:19 +00001317- Note that PyLong_AsDouble can fail! This has always been true, but no
1318 callers checked for it. It's more likely to fail now, because overflow
1319 errors are properly detected now. The proper way to check:
1320
1321 double x = PyLong_AsDouble(some_long_object);
1322 if (x == -1.0 && PyErr_Occurred()) {
1323 /* The conversion failed. */
1324 }
1325
Tim Petersbdee63f2001-09-02 03:40:59 +00001326- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001327 compile but will not participate in GC. To upgrade an extension
1328 module:
1329
1330 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001331
Neil Schemenauer4042c692001-08-30 15:38:01 +00001332 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1333 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001334
Neil Schemenauer4042c692001-08-30 15:38:01 +00001335 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1336 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001337
Neil Schemenauer4042c692001-08-30 15:38:01 +00001338 - remove PyGC_HEAD_SIZE from object size calculations
1339
1340 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1341
Tim Petersbdee63f2001-09-02 03:40:59 +00001342- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001343 These can be used safely to construct string objects from a
1344 sprintf-style format string (similar to the format string supported
1345 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001346
Tim Petersedc99312001-08-22 21:36:50 +00001347New platforms
1348
Tim Petersb7da0902001-09-02 23:01:43 +00001349- Stephen Hansen contributed patches sufficient to get a clean compile
1350 under Borland C (Windows), but he reports problems running it and ran
1351 out of time to complete the port. Volunteers? Expect a MemoryError
1352 when importing the types module; this is probably shallow, and
1353 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001354
Tim Petersedc99312001-08-22 21:36:50 +00001355Tests
1356
1357Windows
1358
Tim Peters6e13a562001-09-06 00:32:15 +00001359- Large file support is now enabled on Win32 platforms as well as on
1360 Win64. This means that, for example, you can use f.tell() and f.seek()
1361 to manipulate files larger than 2 gigabytes (provided you have enough
1362 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001363 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1364 filesize limit, and large file support makes no difference there.
1365 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1366 NTFS has no practical limit on file size, and files of any size can be
1367 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001368
Tim Petersbdee63f2001-09-02 03:40:59 +00001369- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001370 points to command.com (patch from Brian Quinlan).
1371
Tim Petersedc99312001-08-22 21:36:50 +00001372
Tim Peters20f51a72001-07-21 02:31:40 +00001373What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001374Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001375===========================
1376
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001377Build
1378
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001379- Tim Peters developed a brand new Windows installer using Wise 8.1,
1380 generously donated to us by Wise Solutions.
1381
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001382- configure supports a new option --enable-unicode, with the values
1383 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1384 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001385
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001386- A new configure option --enable-framework builds a Mac OS X framework,
1387 which "make frameworkinstall" will install. This provides a starting
1388 point for more mac-like functionality, join pythonmac-sig@python.org
1389 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001390
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001391- The NeXT platform is no longer supported.
1392
1393- The `new' module is now statically linked.
1394
Tim Peters0afb6092001-08-15 06:06:44 +00001395Tools
1396
1397- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001398 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001399 the module docstring for details.
1400
Tim Peters20f51a72001-07-21 02:31:40 +00001401Tests
1402
Tim Peters5e824c32001-08-12 22:25:01 +00001403- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001404 platforms, allowing to give clearer test result output. regrtest
1405 also has optional --use/-u switch to run normally disabled tests
1406 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001407
Tim Peters20f51a72001-07-21 02:31:40 +00001408- Several new tests in the standard test suite, with special thanks to
1409 Nick Mathewson.
1410
1411Core
1412
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001413- The floor division operator // has been added as outlined in PEP
1414 238. The / operator still provides classic division (and will until
1415 Python 3.0) unless "from __future__ import division" is included, in
1416 which case the / operator will provide true division. The operator
1417 module provides truediv() and floordiv() functions. Augmented
1418 assignment variants are included, as are the equivalent overloadable
1419 methods and C API methods. See the PEP for a full discussion:
1420 <http://python.sf.net/peps/pep-0238.html>
1421
Tim Peters6cd6a822001-08-17 22:11:27 +00001422- Future statements are now effective in simulated interactive shells
1423 (like IDLE). This should "just work" by magic, but read Michael
1424 Hudson's "Future statements in simulated shells" PEP 264 for full
1425 details: <http://python.sf.net/peps/pep-0264.html>.
1426
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001427- The type/class unification (PEP 252-253) was integrated into the
1428 trunk and is not so tentative any more (the exact specification of
1429 some features is still tentative). A lot of work has done on fixing
1430 bugs and adding robustness and features (performance still has to
1431 come a long way).
1432
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001433- Warnings about a mismatch in the Python API during extension import
1434 now use the Python warning framework (which makes it possible to
1435 write filters for these warnings).
1436
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001437- A function's __dict__ (aka func_dict) will now always be a
1438 dictionary. It used to be possible to delete it or set it to None,
1439 but now both actions raise TypeErrors. It is still legal to set it
1440 to a dictionary object. Getting func.__dict__ before any attributes
1441 have been assigned now returns an empty dictionary instead of None.
1442
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001443- A new command line option, -E, was added which disables the use of
1444 all environment variables, or at least those that are specifically
1445 significant to Python. Usually those have a name starting with
1446 "PYTHON". This was used to fix a problem where the tests fail if
1447 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1448 older distribution.
1449
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001450Library
1451
Tim Peters5e824c32001-08-12 22:25:01 +00001452- New class Differ and new functions ndiff() and restore() in difflib.py.
1453 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001454 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001455
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001456- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1457 value using the minimal quoting required for the value; more
1458 reliable than using xml.sax.saxutils.escape() for attribute values.
1459
1460- Readline completion support for cmd.Cmd was added.
1461
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001462- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1463
1464- Added function threading.BoundedSemaphore()
1465
1466- Added Ka-Ping Yee's cgitb.py module.
1467
1468- The `new' module now exposes the CO_xxx flags.
1469
Martin v. Löwis560da622001-11-24 09:24:51 +00001470- The gc module offers the get_referents function.
1471
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001472New platforms
1473
1474C API
1475
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001476- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1477 which provide a cross-platform implementations for the
1478 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1479 the standard sprintf() and vsprintf() C lib APIs, these versions
1480 apply bounds checking on the used buffer which enhances protection
1481 against buffer overruns.
1482
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001483- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001484 and extensions using different Unicode widths is rendered next to
1485 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001486 will result in an ImportError. Unicode extensions writers must make
1487 sure to check the Unicode width compatibility in their extensions by
1488 using at least one of the mangled Unicode APIs in the extension.
1489
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001490- Two new flags METH_NOARGS and METH_O are available in method definition
1491 tables to simplify implementation of methods with no arguments and a
1492 single untyped argument. Calling such methods is more efficient than
1493 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1494 deprecated.
1495
Tim Petersc1731372001-08-04 08:12:36 +00001496Windows
1497
1498- "import module" now compiles module.pyw if it exists and nothing else
1499 relevant is found.
1500
Tim Peters20f51a72001-07-21 02:31:40 +00001501
Guido van Rossum55a78992001-07-17 17:22:32 +00001502What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001503Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001504===========================
1505
1506Core
Tim Petersa814db52001-05-14 07:05:58 +00001507
Tim Peters6d6c1a32001-08-02 04:15:00 +00001508- TENTATIVELY, a large amount of code implementing much of what's
1509 described in PEP 252 (Making Types Look More Like Classes) and PEP
1510 253 (Subtyping Built-in Types) was added. This will be released
1511 with Python 2.2a1. Documentation will be provided separately
1512 through http://www.python.org/2.2/. The purpose of releasing this
1513 with Python 2.2a1 is to test backwards compatibility. It is
1514 possible, though not likely, that a decision is made not to release
1515 this code as part of 2.2 final, if any serious backwards
1516 incompapatibilities are found during alpha testing that cannot be
1517 repaired.
1518
Guido van Rossum55a78992001-07-17 17:22:32 +00001519- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001520 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001521 more 'yield' statements. See PEP 255. Since this adds a new
1522 keyword to the language, this feature must be enabled by including a
1523 future statement: "from __future__ import generators" (see PEP 236).
1524 Generators will become a standard feature in a future release
1525 (probably 2.3). Without this future statement, 'yield' remains an
1526 ordinary identifier, but a warning is issued each time it is used.
1527 (These warnings currently don't conform to the warnings framework of
1528 PEP 230; we intend to fix this in 2.2a2.)
1529
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001530- The UTF-16 codec was modified to be more RFC compliant. It will now
1531 only remove BOM characters at the start of the string and then
1532 only if running in native mode (UTF-16-LE and -BE won't remove a
1533 leading BMO character).
1534
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001535- Strings now have a new method .decode() to complement the already
1536 existing .encode() method. These two methods provide direct access
1537 to the corresponding decoders and encoders of the registered codecs.
1538
1539 To enhance the usability of the .encode() method, the special
1540 casing of Unicode object return values was dropped (Unicode objects
1541 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001542
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001543 Both methods will now return whatever the codec in charge of the
1544 requested encoding returns as object, e.g. Unicode codecs will
1545 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1546 will return u"äöü"). This enables codec writer to create codecs
1547 for various simple to use conversions.
1548
1549 New codecs were added to demonstrate these new features (the .encode()
1550 and .decode() columns indicate the type of the returned objects):
1551
1552 Name | .encode() | .decode() | Description
1553 ----------------------------------------------------------------------
1554 uu | string | string | UU codec (e.g. for email)
1555 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001556 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001557 zlib | string | string | zlib compression
1558 hex | string | string | 2-byte hex codec
1559 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1560
Mark Hammond2a0af792001-05-14 03:09:36 +00001561- Some operating systems now support the concept of a default Unicode
1562 encoding for file system operations. Notably, Windows supports 'mbcs'
1563 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001564 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001565 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001566
1567 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001568 functions that return filenames (such as os.listdir()) to return Python
1569 string objects pre-encoded using the default file system encoding for
1570 the platform. As this encoding is likely to be different from Python's
1571 default encoding, converting this name to a Unicode object before passing
1572 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001573 would attempt to use its default encoding (generally ASCII) rather than
1574 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001575
Tim Petersa814db52001-05-14 07:05:58 +00001576 In general, this change simply removes surprises when working with
1577 Unicode and the file system, making these operations work as you expect,
1578 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001579 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001580
Tim Peters61dff2b2001-05-08 15:43:37 +00001581- Float (and complex) literals in source code were evaluated to full
1582 precision only when running from a .py file; the same code loaded from a
1583 .pyc (or .pyo) file could suffer numeric differences starting at about the
1584 12th significant decimal digit. For example, on a machine with IEEE-754
1585 floating arithmetic,
1586
1587 x = 9007199254740992.0
1588 print long(x)
1589
1590 printed 9007199254740992 if run directly from .py, but 9007199254740000
1591 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1592 str(float) instead of repr(float) when building code objects. marshal
1593 now uses repr(float) instead, which should reproduce floats to full
1594 machine precision (assuming the platform C float<->string I/O conversion
1595 functions are of good quality).
1596
1597 This may cause floating-point results to change in some cases, and
1598 usually for the better, but may also cause numerically unstable
1599 algorithms to break.
1600
Tim Peters2f228e72001-05-13 00:19:31 +00001601- The implementation of dicts suffers fewer collisions, which has speed
1602 benefits. However, the order in which dict entries appear in dict.keys(),
1603 dict.values() and dict.items() may differ from previous releases for a
1604 given dict. Nothing is defined about this order, so no program should
1605 rely on it. Nevertheless, it's easy to write test cases that rely on the
1606 order by accident, typically because of printing the str() or repr() of a
1607 dict to an "expected results" file. See Lib/test/test_support.py's new
1608 sortdict(dict) function for a simple way to display a dict in sorted
1609 order.
1610
Tim Peters7a3bfc32001-06-12 01:22:22 +00001611- Many other small changes to dicts were made, resulting in faster
1612 operation along the most common code paths.
1613
Guido van Rossum10315822001-05-01 20:54:30 +00001614- Dictionary objects now support the "in" operator: "x in dict" means
1615 the same as dict.has_key(x).
1616
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001617- The update() method of dictionaries now accepts generic mapping
1618 objects. Specifically the argument object must support the .keys()
1619 and __getitem__() methods. This allows you to say, for example,
1620 {}.update(UserDict())
1621
Guido van Rossum10315822001-05-01 20:54:30 +00001622- Iterators were added; this is a generalized way of providing values
1623 to a for loop. See PEP 234. There's a new built-in function iter()
1624 to return an iterator. There's a new protocol to get the next value
1625 from an iterator using the next() method (in Python) or the
1626 tp_iternext slot (in C). There's a new protocol to get iterators
1627 using the __iter__() method (in Python) or the tp_iter slot (in C).
1628 Iterating (i.e. a for loop) over a dictionary generates its keys.
1629 Iterating over a file generates its lines.
1630
Tim Petersf553f892001-05-01 20:45:31 +00001631- The following functions were generalized to work nicely with iterator
1632 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001633 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001634 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1635 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001636 join() method of strings
1637 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001638 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1639 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001640 right-hand side of assignment statements with multiple targets, such as
1641 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001642
Tim Petersd85e1022001-05-11 21:51:48 +00001643- Accessing module attributes is significantly faster (for example,
1644 random.random or os.path or yourPythonModule.yourAttribute).
1645
Tim Peterse63415e2001-05-08 04:38:29 +00001646- Comparing dictionary objects via == and != is faster, and now works even
1647 if the keys and values don't support comparisons other than ==.
1648
Tim Peters95bf9392001-05-10 08:32:44 +00001649- Comparing dictionaries in ways other than == and != is slower: there were
1650 insecurities in the dict comparison implementation that could cause Python
1651 to crash if the element comparison routines for the dict keys and/or
1652 values mutated the dicts. Making the code bulletproof slowed it down.
1653
Tim Peterseb28ef22001-06-02 05:27:19 +00001654- Collisions in dicts are resolved via a new approach, which can help
1655 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001656 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001657 faster now. Thanks to Christian Tismer for pointing out the cause and
1658 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001659
Tim Peters52e155e2001-06-16 05:42:57 +00001660- repr() is much faster for large containers (dict, list, tuple).
1661
1662
Tim Petersa814db52001-05-14 07:05:58 +00001663Library
1664
Fred Drake960fdf92001-07-20 18:38:26 +00001665- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1666 were added to the string module. These a locale-indenpendent
1667 constants, unlike letters, lowercase, and uppercase. These are now
1668 use in appropriate locations in the standard library.
1669
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001670- The flags used in dlopen calls can now be configured using
1671 sys.setdlopenflags and queried using sys.getdlopenflags.
1672
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001673- Fredrik Lundh's xmlrpclib is now a standard library module. This
1674 provides full client-side XML-RPC support. In addition,
1675 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1676 one asyncore-based). Thanks to Eric Raymond for the documentation.
1677
Guido van Rossum643d3912001-07-05 14:46:25 +00001678- The xrange() object is simplified: it no longer supports slicing,
1679 repetition, comparisons, efficient 'in' checking, the tolist()
1680 method, or the start, stop and step attributes. See PEP 260.
1681
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001682- A new function fnmatch.filter to filter lists of file names was added.
1683
Barry Warsawffd674d2001-05-22 16:00:10 +00001684- calendar.py uses month and day names based on the current locale.
1685
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001686- strop is now *really* obsolete (this was announced before with 1.6),
1687 and issues DeprecationWarning when used (except for the four items
1688 that are still imported into string.py).
1689
Tim Petersa814db52001-05-14 07:05:58 +00001690- Cookie.py now sorts key+value pairs by key in output strings.
1691
1692- pprint.isrecursive(object) didn't correctly identify recursive objects.
1693 Now it does.
1694
Tim Peters95b3f782001-05-14 18:39:41 +00001695- pprint functions now much faster for large containers (tuple, list, dict).
1696
Tim Peters7b9542a2001-06-10 23:40:19 +00001697- New 'q' and 'Q' format codes in the struct module, corresponding to C
1698 types "long long" and "unsigned long long" (on Windows, __int64). In
1699 native mode, these can be used only when the platform C compiler supports
1700 these types (when HAVE_LONG_LONG is #define'd by the Python config
1701 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001702 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1703 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001704
Guido van Rossum83213cc2001-06-12 16:48:52 +00001705- The site module installs a new built-in function 'help' that invokes
1706 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1707 it displays a message reminding the user to use 'help()' or
1708 'help(object)'.
1709
Tim Petersa814db52001-05-14 07:05:58 +00001710Tests
1711
1712- New test_mutants.py runs dict comparisons where the key and value
1713 comparison operators mutute the dicts randomly during comparison. This
1714 rapidly causes Python to crash under earlier releases (not for the faint
1715 of heart: it can also cause Win9x to freeze or reboot!).
1716
1717- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001718 pprint.isreadable() return sensible results. Also verifies that simple
1719 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001720
Tim Peters4324aa32001-05-28 22:30:08 +00001721C API
1722
1723- Removed the unused last_is_sticky argument from the internal
1724 _PyTuple_Resize(). If this affects you, you were cheating.
1725
1726
Guido van Rossum55a78992001-07-17 17:22:32 +00001727======================================================================
1728
1729
Guido van Rossumffe13be2001-04-16 18:46:45 +00001730What's New in Python 2.1 (final)?
1731=================================
1732
1733We only changed a few things since the last release candidate, all in
1734Python library code:
1735
1736- A bug in the locale module was fixed that affected locales which
1737 define no grouping for numeric formatting.
1738
1739- A few bugs in the weakref module's implementations of weak
1740 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1741 and the test suite was updated to check for these bugs.
1742
1743- An old bug in the os.path.walk() function (introduced in Python
1744 2.0!) was fixed: a non-existent file would cause an exception
1745 instead of being ignored.
1746
1747- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1748 PyChecker.
1749
1750
Guido van Rossum5b08f132001-04-16 02:05:23 +00001751What's New in Python 2.1c2?
1752===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001753
Guido van Rossum5b08f132001-04-16 02:05:23 +00001754A flurry of small changes, and one showstopper fixed in the nick of
1755time made it necessary to release another release candidate. The list
1756here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001757
Guido van Rossum5b08f132001-04-16 02:05:23 +00001758Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001759
Guido van Rossum5b08f132001-04-16 02:05:23 +00001760- Tim discovered a nasty bug in the dictionary code, caused by
1761 PyDict_Next() calling dict_resize(), and the GC code's use of
1762 PyDict_Next() violating an assumption in dict_items(). This was
1763 fixed with considerable amounts of band-aid, but the net effect is a
1764 saner and more robust implementation.
1765
1766- Made a bunch of symbols static that were accidentally global.
1767
1768Build and Ports
1769
1770- The setup.py script didn't check for a new enough version of zlib
1771 (1.1.3 is needed). Now it does.
1772
1773- Changed "make clean" target to also remove shared libraries.
1774
1775- Added a more general warning about the SGI Irix optimizer to README.
1776
1777Library
1778
1779- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1780 omitted the slash between host and file.html.
1781
1782- The mailbox module's _Mailbox class contained a completely broken
1783 and undocumented seek() method. Ripped it out.
1784
1785- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1786 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1787
1788- Fixed a few last-minute bugs in unittest.
1789
1790Extensions
1791
1792- Reverted the patch to the OpenSSL code in socketmodule.c to support
1793 RAND_status() and the EGD, and the subsequent patch that tried to
1794 fix it for pre-0.9.5 versions; the problem with the patch is that on
1795 some systems it issues a warning whenever socket is imported, and
1796 that's unacceptable.
1797
1798Tests
1799
1800- Fixed the pickle tests to work with "import test.test_pickle".
1801
1802- Tweaked test_locale.py to actually run the test Windows.
1803
1804- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1805 not "wb" (which is not a valid mode at all).
1806
1807- Fix pstats browser crashes. Import readline if it exists to make
1808 the user interface nicer.
1809
1810- Add "import thread" to the top of test modules that import the
1811 threading module (test_asynchat and test_threadedtempfile). This
1812 prevents test failures caused by a broken threading module resulting
1813 from a previously caught failed import.
1814
1815- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1816 needed on some platforms (e.g. Solaris 8) when the tests are run
1817 twice in succession.
1818
1819- Skip rather than fail test_sunaudiodev if no audio device is found.
1820
1821
1822What's New in Python 2.1c1?
1823===========================
1824
1825This list was significantly updated when 2.1c2 was released; the 2.1c1
1826release didn't mention most changes that were actually part of 2.1c1:
1827
1828Legal
1829
1830- Copyright was assigned to the Python Software Foundation (PSF) and a
1831 PSF license (very similar to the CNRI license) was added.
1832
1833- The CNRI copyright notice was updated to include 2001.
1834
1835Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001836
Guido van Rossumc9932722001-04-12 02:31:27 +00001837- After a public outcry, assignment to __debug__ is no longer illegal;
1838 instead, a warning is issued. It will become illegal in 2.2.
1839
Guido van Rossum5b08f132001-04-16 02:05:23 +00001840- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1841 "%#x" now always prepends "0x", even if the value is zero.
1842
1843- Fixed some nits in the bytecode compiler.
1844
1845- Fixed core dumps when calling certain kinds of non-functions.
1846
1847- Fixed various core dumps caused by reference count bugs.
1848
1849Build and Ports
1850
1851- Use INSTALL_SCRIPT to install script files.
1852
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001853- New port: SCO Unixware 7, by Billy G. Allie.
1854
Guido van Rossum5b08f132001-04-16 02:05:23 +00001855- Updated RISCOS port.
1856
1857- Updated BeOS port and notes.
1858
1859- Various other porting problems resolved.
1860
1861Library
1862
1863- The TERMIOS and SOCKET modules are now truly obsolete and
1864 unnecessary. Their symbols are incorporated in the termios and
1865 socket modules.
1866
1867- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1868 better tests for pickling.
1869
1870- threading: make Condition.wait() robust against KeyboardInterrupt.
1871
1872- zipfile: add support to zipfile to support opening an archive
1873 represented by an open file rather than a file name. Fix bug where
1874 the archive was not properly closed. Fixed a bug in this bugfix
1875 where flush() was called for a read-only file.
1876
1877- imputil: added an uninstall() method to the ImportManager.
1878
1879- Canvas: fixed bugs in lower() and tkraise() methods.
1880
1881- SocketServer: API change (added overridable close_request() method)
1882 so that the TCP server can explicitly close the request.
1883
1884- pstats: Eric Raymond added a simple interactive statistics browser,
1885 invoked when the module is run as a script.
1886
1887- locale: fixed a problem in format().
1888
1889- webbrowser: made it work when the BROWSER environment variable has a
1890 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1891 KDE 2. Fixed some other nits.
1892
1893- unittest: changes to allow using a different exception than
1894 AssertionError, and added a few more function aliases. Some other
1895 small changes.
1896
1897- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1898
1899- asynchat: fixed a critical bug in asynchat that slipped through the
1900 2.1b2 release. Fixed another rare bug.
1901
1902- Fix some unqualified except: clauses (always a bad code example).
1903
1904XML
1905
1906- pyexpat: new API get_version_string().
1907
1908- Fixed some minidom bugs.
1909
1910Extensions
1911
1912- Fixed a core dump in _weakref. Removed the weakref.mapping()
1913 function (it adds nothing to the API).
1914
1915- Rationalized the use of header files in the readline module, to make
1916 it compile (albeit with some warnings) with the very recent readline
1917 4.2, without breaking for earlier versions.
1918
1919- Hopefully fixed a buffering problem in linuxaudiodev.
1920
1921- Attempted a fix to make the OpenSSL support in the socket module
1922 work again with pre-0.9.5 versions of OpenSSL.
1923
1924Tests
1925
1926- Added a test case for asynchat and asyncore.
1927
1928- Removed coupling between tests where one test failing could break
1929 another.
1930
1931Tools
1932
1933- Ping added an interactive help browser to pydoc, fixed some nits
1934 in the rest of the pydoc code, and added some features to his
1935 inspect module.
1936
1937- An updated python-mode.el version 4.1 which integrates Ken
1938 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1939 much nicer in XEmacs and Emacs. When stepping through your program
1940 with pdb, in either the shell window or the *Python* window, the
1941 source file and line will be tracked by an arrow. Very cool!
1942
1943- IDLE: syntax warnings in interactive mode are changed into errors.
1944
1945- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001946 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001947
1948- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001949
Barry Warsaw11e89c72001-04-11 20:37:57 +00001950
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001951What's New in Python 2.1 beta 2?
1952================================
1953
Guido van Rossum053ae352001-03-22 14:17:21 +00001954(Unlisted are many fixed bugs, more documentation, etc.)
1955
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001956Core language, builtins, and interpreter
1957
Guido van Rossum053ae352001-03-22 14:17:21 +00001958- The nested scopes work (enabled by "from __future__ import
1959 nested_scopes") is completed; in particular, the future now extends
1960 into code executed through exec, eval() and execfile(), and into the
1961 interactive interpreter.
1962
1963- When calling a base class method (e.g. BaseClass.__init__(self)),
1964 this is now allowed even if self is not strictly spoken a class
1965 instance (e.g. when using metaclasses or the Don Beaudry hook).
1966
1967- Slice objects are now comparable but not hashable; this prevents
1968 dict[:] from being accepted but meaningless.
1969
1970- Complex division is now calculated using less braindead algorithms.
1971 This doesn't change semantics except it's more likely to give useful
1972 results in extreme cases. Complex repr() now uses full precision
1973 like float repr().
1974
1975- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1976
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001977- It is illegal to assign to the name __debug__, which is set when the
1978 interpreter starts. It is effectively a compile-time constant.
1979
1980- A warning will be issued if a global statement for a variable
1981 follows a use or assignment of that variable.
1982
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001983Standard library
1984
Guido van Rossum053ae352001-03-22 14:17:21 +00001985- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1986 inspired by JUnit), is now part of the standard library. You now
1987 have a choice of two testing frameworks: unittest requires you to
1988 write testcases as separate code, doctest gathers them from
1989 docstrings. Both approaches have their advantages and
1990 disadvantages.
1991
1992- A new module Tix was added, which wraps the Tix extension library
1993 for Tk. With that module, it is not necessary to statically link
1994 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1995 require" command. See Demo/tix/.
1996
1997- tzparse.py is now obsolete.
1998
1999- In gzip.py, the seek() and tell() methods are removed -- they were
2000 non-functional anyway, and it's better if callers can test for their
2001 existence with hasattr().
2002
2003Python/C API
2004
2005- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2006 that's already in the dictionary during a PyDict_Next() iteration.
2007 This used to fail occasionally when a dictionary resize operation
2008 could be triggered that would rehash all the keys. All other
2009 modifications to the dictionary are still off-limits during a
2010 PyDict_Next() iteration!
2011
2012- New extended APIs related to passing compiler variables around.
2013
2014- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2015 implement isinstance() and issubclass().
2016
2017- Py_BuildValue() now has a "D" conversion to create a Python complex
2018 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002019
Fred Drake4e262a92001-03-22 18:26:47 +00002020- Extensions types which support weak references must now set the
2021 field allocated for the weak reference machinery to NULL themselves;
2022 this is done to avoid the cost of checking each object for having a
2023 weakly referencable type in PyObject_INIT(), since most types are
2024 not weakly referencable.
2025
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002026- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2027 free variables and cell variables to and from the frame's f_locals.
2028
2029- Variants of several functions defined in pythonrun.h have been added
2030 to support the nested_scopes future statement. The variants all end
2031 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2032 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2033 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002034 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002035
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002036Distutils
2037
2038- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2039 into the release tree.
2040
Tim Peters0e57abf2001-05-02 07:39:38 +00002041- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002042 (an uninstaller, more customization of the installer's display)
2043
2044- from Jack Jansen: added Mac-specific code to generate a dialog for
2045 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002046 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002047 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002048
2049- added 'platforms' and 'keywords' to the set of metadata that can be
2050 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002051
2052- applied patches from Jason Tishler to make the compiler class work with
2053 Cygwin.
2054
2055
Tim Peters2fe289a2001-03-01 22:19:38 +00002056What's New in Python 2.1 beta 1?
2057================================
Tim Petersd66595f2001-02-04 03:09:53 +00002058
2059Core language, builtins, and interpreter
2060
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002061- Following an outcry from the community about the amount of code
2062 broken by the nested scopes feature introduced in 2.1a2, we decided
2063 to make this feature optional, and to wait until Python 2.2 (or at
2064 least 6 months) to make it standard. The option can be enabled on a
2065 per-module basis by adding "from __future__ import nested_scopes" at
2066 the beginning of a module (before any other statements, but after
2067 comments and an optional docstring). See PEP 236 (Back to the
2068 __future__) for a description of the __future__ statement. PEP 227
2069 (Statically Nested Scopes) has been updated to reflect this change,
2070 and to clarify the semantics in a number of endcases.
2071
2072- The nested scopes code, when enabled, has been hardened, and most
2073 bugs and memory leaks in it have been fixed.
2074
2075- Compile-time warnings are now generated for a number of conditions
2076 that will break or change in meaning when nested scopes are enabled:
2077
2078 - Using "from...import *" or "exec" without in-clause in a function
2079 scope that also defines a lambda or nested function with one or
2080 more free (non-local) variables. The presence of the import* or
2081 bare exec makes it impossible for the compiler to determine the
2082 exact set of local variables in the outer scope, which makes it
2083 impossible to determine the bindings for free variables in the
2084 inner scope. To avoid the warning about import *, change it into
2085 an import of explicitly name object, or move the import* statement
2086 to the global scope; to avoid the warning about bare exec, use
2087 exec...in... (a good idea anyway -- there's a possibility that
2088 bare exec will be deprecated in the future).
2089
2090 - Use of a global variable in a nested scope with the same name as a
2091 local variable in a surrounding scope. This will change in
2092 meaning with nested scopes: the name in the inner scope will
2093 reference the variable in the outer scope rather than the global
2094 of the same name. To avoid the warning, either rename the outer
2095 variable, or use a global statement in the inner function.
2096
Neil Schemenauera35c6882001-02-27 04:45:05 +00002097- An optional object allocator has been included. This allocator is
2098 optimized for Python objects and should be faster and use less memory
2099 than the standard system allocator. It is not enabled by default
2100 because of possible thread safety problems. The allocator is only
2101 protected by the Python interpreter lock and it is possible that some
2102 extension modules require a thread safe allocator. The object
2103 allocator can be enabled by providing the "--with-pymalloc" option to
2104 configure.
2105
Tim Petersd66595f2001-02-04 03:09:53 +00002106Standard library
2107
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002108- pyexpat now detects the expat version if expat.h defines it. A
2109 number of additional handlers are provided, which are only available
2110 since expat 1.95. In addition, the methods SetParamEntityParsing and
2111 GetInputContext of Parser objects are available with 1.95.x
2112 only. Parser objects now provide the ordered_attributes and
2113 specified_attributes attributes. A new module expat.model was added,
2114 which offers a number of additional constants if 1.95.x is used.
2115
2116- xml.dom offers the new functions registerDOMImplementation and
2117 getDOMImplementation.
2118
2119- xml.dom.minidom offers a toprettyxml method. A number of DOM
2120 conformance issues have been resolved. In particular, Element now
2121 has an hasAttributes method, and the handling of namespaces was
2122 improved.
2123
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002124- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2125 getting information about live Python code, and pydoc.py, a module
2126 for interactively converting docstrings to HTML or text.
2127 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002128 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002129 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2130 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002131
Tim Peters1eff7962001-03-01 02:31:33 +00002132- New library module difflib.py, primarily packaging the SequenceMatcher
2133 class at the heart of the popular ndiff.py file-comparison tool.
2134
2135- doctest.py (a framework for verifying Python code examples in docstrings)
2136 is now part of the std library.
2137
Tim Petersd66595f2001-02-04 03:09:53 +00002138Windows changes
2139
Guido van Rossume3955a82001-03-02 14:05:59 +00002140- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2141 small GUI that lets you browse the module docstrings using your
2142 default web browser.
2143
Tim Peters1eff7962001-03-01 02:31:33 +00002144- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2145 Platforms) is implemented. See
2146
2147 http://python.sourceforge.net/peps/pep-0235.html
2148
2149 for full details, especially the "Current Lower-Left Semantics" section.
2150 The new Windows import rules are simpler than before:
2151
2152 A. If the PYTHONCASEOK environment variable exists, same as
2153 before: silently accept the first case-insensitive match of any
2154 kind; raise ImportError if none found.
2155
2156 B. Else search sys.path for the first case-sensitive match; raise
2157 ImportError if none found.
2158
2159 The same rules have been implented on other platforms with case-
2160 insensitive but case-preserving filesystems too (including Cygwin, and
2161 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002162
Tim Peters25a9ce32001-02-19 07:06:36 +00002163- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2164 what it's supposed to do (and does do under NT and 2000) via direct
2165 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002166 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002167 all Win9x systems before.
2168
Tim Peters1eff7962001-03-01 02:31:33 +00002169- Build: Subproject _test (effectively) renamed to _testcapi.
2170
Tim Peters2fe289a2001-03-01 22:19:38 +00002171New platforms
2172
2173- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2174 Thanks to Steven Majewski!
2175
2176- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2177 Tishler!
2178
Guido van Rossum9089b272001-03-02 06:49:50 +00002179- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2180 Schwertberger! See RISCOS/README for more information -- it seems
2181 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002182 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002183
Tim Peters25a9ce32001-02-19 07:06:36 +00002184
Tim Petersd7b5e882001-01-25 03:36:26 +00002185What's New in Python 2.1 alpha 2?
2186=================================
Tim Peters40ead762001-01-27 05:35:26 +00002187
Tim Petersd7b5e882001-01-25 03:36:26 +00002188Core language, builtins, and interpreter
2189
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002190- Scopes nest. If a name is used in a function or class, but is not
2191 local, the definition in the nearest enclosing function scope will
2192 be used. One consequence of this change is that lambda statements
2193 could reference variables in the namespaces where the lambda is
2194 defined. In some unusual cases, this change will break code.
2195
2196 In all previous version of Python, names were resolved in exactly
2197 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002198 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002199 function A is defined within a function B, the names bound in B are
2200 not visible in A. The new rules make names bound in B visible in A,
2201 unless A contains a name binding that hides the binding in B.
2202
2203 Section 4.1 of the reference manual describes the new scoping rules
2204 in detail. The test script in Lib/test/test_scope.py demonstrates
2205 some of the effects of the change.
2206
2207 The new rules will cause existing code to break if it defines nested
2208 functions where an outer function has local variables with the same
2209 name as globals or builtins used by the inner function. Example:
2210
2211 def munge(str):
2212 def helper(x):
2213 return str(x)
2214 if type(str) != type(''):
2215 str = helper(str)
2216 return str.strip()
2217
2218 Under the old rules, the name str in helper() is bound to the
2219 builtin function str(). Under the new rules, it will be bound to
2220 the argument named str and an error will occur when helper() is
2221 called.
2222
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002223- The compiler will report a SyntaxError if "from ... import *" occurs
2224 in a function or class scope. The language reference has documented
2225 that this case is illegal, but the compiler never checked for it.
2226 The recent introduction of nested scope makes the meaning of this
2227 form of name binding ambiguous. In a future release, the compiler
2228 may allow this form when there is no possibility of ambiguity.
2229
Tim Peters40ead762001-01-27 05:35:26 +00002230- repr(string) is easier to read, now using hex escapes instead of octal,
2231 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2232
2233 >>> "\texample \r\n" + chr(0) + chr(255)
2234 '\texample \r\n\x00\xff' # in 2.1
2235 '\011example \015\012\000\377' # in 2.0
2236
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002237- Functions are now compared and hashed by identity, not by value, since
2238 the func_code attribute is writable.
2239
Fred Drakefb9d7122001-02-01 20:00:40 +00002240- Weak references (PEP 205) have been added. This involves a few
2241 changes in the core, an extension module (_weakref), and a Python
2242 module (weakref). The weakref module is the public interface. It
2243 includes support for "explicit" weak references, proxy objects, and
2244 mappings with weakly held values.
2245
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002246- A 'continue' statement can now appear in a try block within the body
2247 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002248 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002249
Tim Petersd7b5e882001-01-25 03:36:26 +00002250Standard library
2251
Barry Warsaw30dbd142001-01-31 22:14:01 +00002252- mailbox.py now has a new class, PortableUnixMailbox which is
2253 identical to UnixMailbox but uses a more portable scheme for
2254 determining From_ separators. Also, the constructors for all the
2255 classes in this module have a new optional `factory' argument, which
2256 is a callable used when new message classes must be instantiated by
2257 the next() method.
2258
Tim Petersd7b5e882001-01-25 03:36:26 +00002259- random.py is now self-contained, and offers all the functionality of
2260 the now-deprecated whrandom.py. See the docs for details. random.py
2261 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002262 and restoring the internal state of the generator; and jumpahead(n),
2263 for quickly forcing the internal state to be the same as if n calls to
2264 random() had been made. The latter is particularly useful for multi-
2265 threaded programs, creating one instance of the random.Random() class for
2266 each thread, then using .jumpahead() to force each instance to use a
2267 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002268
Tim Peters0de88fc2001-02-01 04:59:18 +00002269- random.py's seed() function is new. For bit-for-bit compatibility with
2270 prior releases, use the whseed function instead. The new seed function
2271 addresses two problems: (1) The old function couldn't produce more than
2272 about 2**24 distinct internal states; the new one about 2**45 (the best
2273 that can be done in the Wichmann-Hill generator). (2) The old function
2274 sometimes produced identical internal states when passed distinct
2275 integers, and there was no simple way to predict when that would happen;
2276 the new one guarantees to produce distinct internal states for all
2277 arguments in [0, 27814431486576L).
2278
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002279- The socket module now supports raw packets on Linux. The socket
2280 family is AF_PACKET.
2281
Tim Peters9ea17ac2001-02-02 05:57:15 +00002282- test_capi.py is a start at running tests of the Python C API. The tests
2283 are implemented by the new Modules/_testmodule.c.
2284
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002285- A new extension module, _symtable, provides provisional access to the
2286 internal symbol table used by the Python compiler. A higher-level
2287 interface will be added on top of _symtable in a future release.
2288
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002289- Removed the obsolete soundex module.
2290
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002291- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2292 the isSameNode method; NamedNodeMap the get method.
2293
2294- xml.sax.expatreader supports the lexical handler property; it
2295 generates comment, startCDATA, and endCDATA events.
2296
Tim Petersee826f82001-01-31 19:39:44 +00002297Windows changes
2298
2299- Build procedure: the zlib project is built in a different way that
2300 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002301 the zlib binary used. See PCbuild\readme.txt for details. Your old
2302 zlib-related directories can be deleted; you'll need to download fresh
2303 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002304
Tim Peters9ea17ac2001-02-02 05:57:15 +00002305- Build: New subproject _test for the benefit of test_capi.py (see above).
2306
Tim Petersb16c56f2001-02-02 21:24:51 +00002307- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2308 interface to some Python compiler internals).
2309
2310- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002311 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002312
Tim Petersa3a3a032000-11-30 05:22:44 +00002313What's New in Python 2.1 alpha 1?
2314=================================
2315
2316Core language, builtins, and interpreter
2317
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002318- There is a new Unicode companion to the PyObject_Str() API
2319 called PyObject_Unicode(). It behaves in the same way as the
2320 former, but assures that the returned value is an Unicode object
2321 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002322
Guido van Rossumf98eda02001-01-17 15:54:45 +00002323- The comparison operators support "rich comparison overloading" (PEP
2324 207). C extension types can provide a rich comparison function in
2325 the new tp_richcompare slot in the type object. The cmp() function
2326 and the C function PyObject_Compare() first try the new rich
2327 comparison operators before trying the old 3-way comparison. There
2328 is also a new C API PyObject_RichCompare() (which also falls back on
2329 the old 3-way comparison, but does not constrain the outcome of the
2330 rich comparison to a Boolean result).
2331
2332 The rich comparison function takes two objects (at least one of
2333 which is guaranteed to have the type that provided the function) and
2334 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2335 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2336 object, which may be NotImplemented (in which case the tp_compare
2337 slot function is used as a fallback, if defined).
2338
2339 Classes can overload individual comparison operators by defining one
2340 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002341 __ge__. There are no explicit "reflected argument" versions of
2342 these; instead, __lt__ and __gt__ are each other's reflection,
2343 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2344 reflection (similar at the C level). No other implications are
2345 made; in particular, Python does not assume that == is the Boolean
2346 inverse of !=, or that < is the Boolean inverse of >=. This makes
2347 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002348
2349 Classes or types that want to implement (in)equality tests but not
2350 the ordering operators (i.e. unordered types) should implement ==
2351 and !=, and raise an error for the ordering operators.
2352
Guido van Rossuma88479f2001-01-18 14:28:08 +00002353 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002354 Boolean; e.g. a matrix type might want to return a matrix of bits
2355 for A < B, giving elementwise comparisons. Such types should ensure
2356 that any interpretation of their value in a Boolean context raises
2357 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2358 at the C level) to always raise an exception.
2359
Guido van Rossuma88479f2001-01-18 14:28:08 +00002360- Complex numbers use rich comparisons to define == and != but raise
2361 an exception for <, <=, > and >=. Unfortunately, this also means
2362 that cmp() of two complex numbers raises an exception when the two
2363 numbers differ. Since it is not mathematically meaningful to compare
2364 complex numbers except for equality, I hope that this doesn't break
2365 too much code.
2366
Tim Peters3389f192001-02-18 08:48:49 +00002367- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002368 not defined by the language, other than that it's arbitrary but
2369 consistent (see the Reference Manual). An implementation detail changed
2370 in 2.1a1 such that None now compares less than any other object. Code
2371 relying on this new behavior (like code that relied on the previous
2372 behavior) does so at its own risk.
2373
Barry Warsaw573b5412001-01-15 20:43:18 +00002374- Functions and methods now support getting and setting arbitrarily
2375 named attributes (PEP 232). Functions have a new __dict__
2376 (a.k.a. func_dict) which hold the function attributes. Methods get
2377 and set attributes on their underlying im_func. It is a TypeError
2378 to set an attribute on a bound method.
2379
Guido van Rossum051e3352001-01-15 19:11:10 +00002380- The xrange() object implementation has been improved so that
2381 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2382 limitation that in this case len(xrange(sys.maxint)) can't be
2383 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2384 work fine as long as the index i doesn't actually reach 2**31.
2385 (Python uses regular ints for sequence and string indices; fixing
2386 that is much more work.)
2387
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002388- Two changes to from...import:
2389
Guido van Rossumba381232001-02-03 15:06:40 +00002390 1) "from M import X" now works even if (after loading module M)
2391 sys.modules['M'] is not a real module; it's basically a getattr()
2392 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002393
2394 2) "from M import *" now looks for M.__all__ to decide which names to
2395 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2396 filters out names starting with '_' as before. Whether or not
2397 __all__ exists, there's no restriction on the type of M.
2398
Guido van Rossumf61f1662001-01-10 20:13:55 +00002399- File objects have a new method, xreadlines(). This is the fastest
2400 way to iterate over all lines in a file:
2401
2402 for line in file.xreadlines():
2403 ...do something to line...
2404
2405 See the xreadlines module (mentioned below) for how to do this for
2406 other file-like objects.
2407
2408- Even if you don't use file.xreadlines(), you may expect a speedup on
2409 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002410 quite a bit in platform-specific ways: on systems (like Linux) that
2411 support flockfile(), getc_unlocked(), and funlockfile(), those are
2412 used by default. On systems (like Windows) without getc_unlocked(),
2413 a complicated (but still thread-safe) method using fgets() is used by
2414 default.
2415
Tim Petersd52269b2001-01-25 06:23:18 +00002416 You can force use of the fgets() method by #define'ing
2417 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002418 getc_unlocked()).
2419
Tim Petersd52269b2001-01-25 06:23:18 +00002420 You can force fgets() not to be used by #define'ing
2421 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002422 test_bufio.py fails -- and let us know if it does!).
2423
2424- In addition, the fileinput module, while still slower than the other
2425 methods on most platforms, has been sped up too, by using
2426 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002427
2428- Support for run-time warnings has been added, including a new
2429 command line option (-W) to specify the disposition of warnings.
2430 See the description of the warnings module below.
2431
2432- Extensive changes have been made to the coercion code. This mostly
2433 affects extension modules (which can now implement mixed-type
2434 numerical operators without having to use coercion), but
2435 occasionally, in boundary cases the coercion semantics have changed
2436 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002437 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002438 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002439 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002440
Guido van Rossumf98eda02001-01-17 15:54:45 +00002441- In connection with the coercion changes, a new built-in singleton
2442 object, NotImplemented is defined. This can be returned for
2443 operations that wish to indicate they are not implemented for a
2444 particular combination of arguments. From C, this is
2445 Py_NotImplemented.
2446
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002447- The interpreter accepts now bytecode files on the command line even
2448 if they do not have a .pyc or .pyo extension. On Linux, after executing
2449
Martin v. Löwise214baa2001-02-04 22:37:56 +00002450import imp,sys,string
2451magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2452reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2453open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002454
2455 any byte code file can be used as an executable (i.e. as an argument
2456 to execve(2)).
2457
Tim Peters9940b802000-12-01 07:59:35 +00002458- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002459 character. In 1.6 and earlier, they never produced a sign,
2460 and raised an error if the value of the long was too large
2461 to fit in a Python int. In 2.0, they produced a sign if and
2462 only if too large to fit in an int. This was inconsistent
2463 across platforms (because the size of an int varies across
2464 platforms), and inconsistent with hex() and oct(). Example:
2465
2466 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002467 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002468 'ffffffbe' # in 2.0 and before, on 32-bit machines
2469 >>> hex(-0x42L)
2470 '-0x42L' # in all versions of Python
2471
Tim Peters9940b802000-12-01 07:59:35 +00002472 The behavior of %d formats for negative Python longs remains
2473 the same as in 2.0 (although in 1.6 and before, they raised
2474 an error if the long didn't fit in a Python int).
2475
2476 %u formats don't make sense for Python longs, but are allowed
2477 and treated the same as %d in 2.1. In 2.0, a negative long
2478 formatted via %u produced a sign if and only if too large to
2479 fit in an int. In 1.6 and earlier, a negative long formatted
2480 via %u raised an error if it was too big to fit in an int.
2481
Guido van Rossum3661d392000-12-12 22:10:31 +00002482- Dictionary objects have an odd new method, popitem(). This removes
2483 an arbitrary item from the dictionary and returns it (in the form of
2484 a (key, value) pair). This can be useful for algorithms that use a
2485 dictionary as a bag of "to do" items and repeatedly need to pick one
2486 item. Such algorithms normally end up running in quadratic time;
2487 using popitem() they can usually be made to run in linear time.
2488
Tim Peters36cdad12000-12-29 02:06:45 +00002489Standard library
2490
Thomas Woutersfe385252001-01-19 23:16:56 +00002491- In the time module, the time argument to the functions strftime,
2492 localtime, gmtime, asctime and ctime is now optional, defaulting to
2493 the current time (in the local timezone).
2494
Guido van Rossumda91f222001-01-15 16:36:08 +00002495- The ftplib module now defaults to passive mode, which is deemed a
2496 more useful default given that clients are often inside firewalls
2497 these days. Note that this could break if ftplib is used to connect
2498 to a *server* that is inside a firewall, from outside; this is
2499 expected to be a very rare situation. To fix that, you can call
2500 ftp.set_pasv(0).
2501
Martin v. Löwis10a27872001-01-13 09:54:41 +00002502- The module site now treats .pth files not only for path configuration,
2503 but also supports extensions to the initialization code: Lines starting
2504 with import are executed.
2505
Guido van Rossumf61f1662001-01-10 20:13:55 +00002506- There's a new module, warnings, which implements a mechanism for
2507 issuing and filtering warnings. There are some new built-in
2508 exceptions that serve as warning categories, and a new command line
2509 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2510 turns warnings into errors). warnings.warn(message[, category])
2511 issues a warning message; this can also be called from C as
2512 PyErr_Warn(category, message).
2513
2514- A new module xreadlines was added. This exports a single factory
2515 function, xreadlines(). The intention is that this code is the
2516 absolutely fastest way to iterate over all lines in an open
2517 file(-like) object:
2518
2519 import xreadlines
2520 for line in xreadlines.xreadlines(file):
2521 ...do something to line...
2522
2523 This is equivalent to the previous the speed record holder using
2524 file.readlines(sizehint). Note that if file is a real file object
2525 (as opposed to a file-like object), this is equivalent:
2526
2527 for line in file.xreadlines():
2528 ...do something to line...
2529
Tim Peters36cdad12000-12-29 02:06:45 +00002530- The bisect module has new functions bisect_left, insort_left,
2531 bisect_right and insort_right. The old names bisect and insort
2532 are now aliases for bisect_right and insort_right. XXX_right
2533 and XXX_left methods differ in what happens when the new element
2534 compares equal to one or more elements already in the list: the
2535 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002536 right. Code that doesn't care where equal elements end up should
2537 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002538
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002539- The new curses.panel module wraps the panel library that forms part
2540 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2541
Guido van Rossumf61f1662001-01-10 20:13:55 +00002542- The SocketServer module now sets the allow_reuse_address flag by
2543 default in the TCPServer class.
2544
2545- A new function, sys._getframe(), returns the stack frame pointer of
2546 the caller. This is intended only as a building block for
2547 higher-level mechanisms such as string interpolation.
2548
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002549- The pyexpat module supports a number of new handlers, which are
2550 available only in expat 1.2. If invocation of a callback fails, it
2551 will report an additional frame in the traceback. Parser objects
2552 participate now in garbage collection. If expat reports an unknown
2553 encoding, pyexpat will try to use a Python codec; that works only
2554 for single-byte charsets. The parser type objects is exposed as
2555 XMLParserObject.
2556
2557- xml.dom now offers standard definitions for symbolic node type and
2558 exception code constants, and a hierarchy of DOM exceptions. minidom
2559 was adjusted to use them.
2560
2561- The conformance of xml.dom.minidom to the DOM specification was
2562 improved. It detects a number of additional error cases; the
2563 previous/next relationship works even when the tree is modified;
2564 Node supports the normalize() method; NamedNodeMap, DocumentType and
2565 DOMImplementation classes were added; Element supports the
2566 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2567 method.
2568
Guido van Rossumf61f1662001-01-10 20:13:55 +00002569Build issues
2570
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002571- For Unix (and Unix-compatible) builds, configuration and building of
2572 extension modules is now greatly automated. Rather than having to
2573 edit the Modules/Setup file to indicate which modules should be
2574 built and where their include files and libraries are, a
2575 distutils-based setup.py script now takes care of building most
2576 extension modules. All extension modules built this way are built
2577 as shared libraries. Only a few modules that must be linked
2578 statically are still listed in the Setup file; you won't need to
2579 edit their configuration.
2580
2581- Python should now build out of the box on Cygwin. If it doesn't,
2582 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002583
2584- Python now always uses its own (renamed) implementation of getopt()
2585 -- there's too much variation among C library getopt()
2586 implementations.
2587
2588- C++ compilers are better supported; the CXX macro is always set to a
2589 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002590
Tim Petersd92dfe02000-12-12 01:18:41 +00002591Windows changes
2592
2593- select module: By default under Windows, a select() call
2594 can specify no more than 64 sockets. Python now boosts
2595 this Microsoft default to 512. If you need even more than
2596 that, see the MS docs (you'll need to #define FD_SETSIZE
2597 and recompile Python from source).
2598
Guido van Rossumf61f1662001-01-10 20:13:55 +00002599- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2600 subdirectory is no more!
2601
Tim Petersa3a3a032000-11-30 05:22:44 +00002602
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002603What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002604=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002605
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002606Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002607changes are in the file HISTORY. If you are making the jump directly
2608from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2609HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002610
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002611Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2612the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2613http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002614
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002615--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002616
2617======================================================================
2618
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002619What's new in 2.0 (since release candidate 1)?
2620==============================================
2621
2622Standard library
2623
2624- The copy_reg module was modified to clarify its intended use: to
2625 register pickle support for extension types, not for classes.
2626 pickle() will raise a TypeError if it is passed a class.
2627
2628- Fixed a bug in gettext's "normalize and expand" code that prevented
2629 it from finding an existing .mo file.
2630
2631- Restored support for HTTP/0.9 servers in httplib.
2632
Tim Peters989b7b92000-10-16 20:24:53 +00002633- The math module was changed to stop raising OverflowError in case of
2634 underflow, and return 0 instead in underflow cases. Whether Python
2635 used to raise OverflowError in case of underflow was platform-
2636 dependent (it did when the platform math library set errno to ERANGE
2637 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002638
2639- Fixed a bug in StringIO that occurred when the file position was not
2640 at the end of the file and write() was called with enough data to
2641 extend past the end of the file.
2642
2643- Fixed a bug that caused Tkinter error messages to get lost on
2644 Windows. The bug was fixed by replacing direct use of
2645 interp->result with Tcl_GetStringResult(interp).
2646
2647- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2648 redirect response.
2649
2650- Several changes were made to distutils: Some debugging code was
2651 removed from util. Fixed the installer used when an external zip
2652 program (like WinZip) is not found; the source code for this
2653 installer is in Misc/distutils. check_lib() was modified to behave
2654 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2655 test for whether installed modules are on sys.path was changed to
2656 use both normcase() and normpath().
2657
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002658- Several minor bugs were fixed in the xml package (the minidom,
2659 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002660
2661- The regression test driver (regrtest.py) behavior when invoked with
2662 -l changed: It now reports a count of objects that are recognized as
2663 garbage but not freed by the garbage collector.
2664
Tim Peters989b7b92000-10-16 20:24:53 +00002665- The regression test for the math module was changed to test
2666 exceptional behavior when the test is run in verbose mode. Python
2667 cannot yet guarantee consistent exception behavior across platforms,
2668 so the exception part of test_math is run only in verbose mode, and
2669 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002670
2671Internals
2672
2673- PyOS_CheckStack() has been disabled on Win64, where it caused
2674 test_sre to fail.
2675
2676Build issues
2677
2678- Changed compiler flags, so that gcc is always invoked with -Wall and
2679 -Wstrict-prototypes. Users compiling Python with GCC should see
2680 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002681 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002682 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002683
Tim Petersa3a3a032000-11-30 05:22:44 +00002684- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002685
2686Tools and other miscellany
2687
2688- The compiler in Tools/compiler was updated to support the new
2689 language features introduced in 2.0: extended print statement, list
2690 comprehensions, and augmented assignments. The new compiler should
2691 also be backwards compatible with Python 1.5.2; the compiler will
2692 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002693 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002694
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002695What's new in 2.0 release candidate 1 (since beta 2)?
2696=====================================================
2697
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002698What is release candidate 1?
2699
2700We believe that release candidate 1 will fix all known bugs that we
2701intend to fix for the 2.0 final release. This release should be a bit
2702more stable than the previous betas. We would like to see even more
2703widespread testing before the final release, so we are producing this
2704release candidate. The final release will be exactly the same unless
2705any show-stopping (or brown bag) bugs are found by testers of the
2706release candidate.
2707
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002708All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002709to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002710
2711Core language, builtins, and interpreter
2712
2713- A bug that caused crashes when __coerce__ was used with augmented
2714 assignment, e.g. +=, was fixed.
2715
2716- Raise ZeroDivisionError when raising zero to a negative number,
2717 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2718 power operator and the result of math.pow(0.0, -2.0) will vary by
2719 platform. On Linux, it raises a ValueError.
2720
2721- A bug in Unicode string interpolation was fixed that occasionally
2722 caused errors with formats including "%%". For example, the
2723 following expression "%% %s" % u"abc" no longer raises a TypeError.
2724
2725- Compilation of deeply nested expressions raises MemoryError instead
2726 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2727
2728- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2729 rendering them useless. They are now written in binary mode again.
2730
2731Standard library
2732
2733- Keyword arguments are now accepted for most pattern and match object
2734 methods in SRE, the standard regular expression engine.
2735
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002736- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002737 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002738
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002739- Several bugs in the Unicode handling and error handling in _tkinter
2740 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002741
2742- Fix memory management errors in Merge() and Tkapp_Call() routines.
2743
2744- Several changes were made to cStringIO to make it compatible with
2745 the file-like object interface and with StringIO. If operations are
2746 performed on a closed object, an exception is raised. The truncate
2747 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002748 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002749
2750- There were many changes made to the linuxaudiodev module and its
2751 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002752 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002753
2754 Note that this module is named poorly, because it should work
2755 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002756 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002757
2758 The module now raises exceptions when errors occur instead of
2759 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2760 audio) and defines a getptr() method that calls the
2761 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2762
2763- The library_version attribute, introduced in an earlier beta, was
2764 removed because it can not be supported with early versions of the C
2765 readline library, which provides no way to determine the version at
2766 compile-time.
2767
2768- The binascii module is now enabled on Win64.
2769
Tim Peters46446d62000-10-09 21:19:31 +00002770- tokenize.py no longer suffers "recursion depth" errors when parsing
2771 programs with very long string literals.
2772
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002773Internals
2774
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002775- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002776 which is called when the interpreter starts up to determine where
2777 the standard library is installed. These vulnerabilities affect all
2778 previous versions of Python and can be exploited by setting very
2779 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2780 setuid Python script, although use of the wrapper in
2781 Misc/setuid-prog.c will eliminate the vulnerability.
2782
2783- Fixed garbage collection bugs in instance creation that were
2784 triggered when errors occurred during initialization. The solution,
2785 applied in cPickle and in PyInstance_New(), is to call
2786 PyObject_GC_Init() after the initialization of the object's
2787 container attributes is complete.
2788
2789- pyexpat adds definitions of PyModule_AddStringConstant and
2790 PyModule_AddObject if the Python version is less than 2.0, which
2791 provides compatibility with PyXML on Python 1.5.2.
2792
2793- If the platform has a bogus definition for LONG_BIT (the number of
2794 bits in a long), an error will be reported at compile time.
2795
2796- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2797 collection crashes and possibly other, unreported crashes.
2798
2799- Fixed a memory leak in _PyUnicode_Fini().
2800
2801Build issues
2802
2803- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002804 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002805 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002806
2807- The mmap.PAGESIZE constant is now initialized using sysconf when
2808 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2809
2810- The md5 file should now compile on all platforms.
2811
2812- The select module now compiles on platforms that do not define
2813 POLLRDNORM and related constants.
2814
2815- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002816 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002817
Jeremy Hylton10921202000-10-09 18:34:12 +00002818- BeOS: A number of changes were made to the build and installation
2819 process. ar-fake now operates on a directory of object files.
2820 dl_export.h is gone, and its macros now appear on the mwcc command
2821 line during build on PPC BeOS.
2822
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002823- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002824 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002825
2826- Cygwin: Support for shared libraries, Tkinter, and sockets.
2827
2828- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2829
2830Tools and other miscellany
2831
2832- Removed debugging prints from main used with freeze.
2833
Tim Peters46446d62000-10-09 21:19:31 +00002834- IDLE auto-indent no longer crashes when it encounters Unicode
2835 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002836
2837What's new in 2.0 beta 2 (since beta 1)?
2838========================================
2839
2840Core language, builtins, and interpreter
2841
Tim Peters482c0212000-09-26 06:33:09 +00002842- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002843 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002844
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002845- Add -h and -V command line options to print the usage message and
2846 Python version number and exit immediately.
2847
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002848- eval() and exec accept Unicode objects as code parameters.
2849
2850- getattr() and setattr() now also accept Unicode objects for the
2851 attribute name, which are converted to strings using the default
2852 encoding before lookup.
2853
2854- Multiplication on string and Unicode now does proper bounds
2855 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2856 string is too long."
2857
2858- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002859 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002860
Jeremy Hylton1b618592000-09-26 05:32:36 +00002861
2862Standard library and extensions
2863
Guido van Rossum5b08f132001-04-16 02:05:23 +00002864- socket module: the OpenSSL code now adds support for RAND_status()
2865 and EGD (Entropy Gathering Device).
2866
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002867- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002868 argument checking; it still takes no arguments.
2869
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002870- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002871
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002872- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002873
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002874- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002875
2876- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002877 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878
2879- copy: Copy Unicode objects atomically.
2880
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002881- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002883- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002884
Fred Drake67233bc2000-09-26 16:40:27 +00002885- dbm: Add get() and setdefault() methods to dbm object. Add constant
2886 `library' to module that names the library used. Added doc strings
2887 and method names to error messages. Uses configure to determine
2888 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2889 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002890
2891- distutils: Update to version 0.9.3.
2892
2893- dl: Add several dl.RTLD_ constants.
2894
2895- fpectl: Now supported on FreeBSD.
2896
2897- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2898 found by the collector will be saved in gc.garbage. This is useful
2899 for debugging a program that creates reference cycles.
2900
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002901- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902 of HTTP class. Do not close socket on zero-length response. Do not
2903 crash when server sends invalid content-length header.
2904
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002905- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002906
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002907- marshal: When reading a short, sign-extend on platforms where shorts
2908 are bigger than 16 bits. When reading a long, repair the unportable
2909 sign extension that was being done for 64-bit machines. (It assumed
2910 that signed right shift sign-extends.)
2911
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002912- operator: Add contains(), invert(), __invert__() as aliases for
2913 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002914
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002915- os: Add support for popen2() and popen3() on all platforms where
2916 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002917
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002918- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002919 clicking on a file in Explorer (or passing the file name to the
2920 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002921
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002922- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002923 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002924
2925- pickle: Now raises ValueError when an invalid pickle that contains
2926 a non-string repr where a string repr was expected. This behavior
2927 matches cPickle.
2928
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002929- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002930
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002931- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002932
2933- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002934 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002935 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002936
2937- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002938 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002939
2940- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002941 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002942 few cycles during startup since the first call to
2943 setdefaultencoding() will initialize the codec registry and the
2944 encodings package.
2945
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002946- socket: Support for size hint in readlines() method of object returned
2947 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002948
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002949- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002950 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002951 is followed by whitespace.
2952
Tim Petersa3a3a032000-11-30 05:22:44 +00002953- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002954
2955- struct: Check ranges for bytes and shorts.
2956
2957- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002958 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002959
2960- Tkinter: Image objects are now guaranteed to have unique ids. Set
2961 event.delta to zero if Tk version doesn't support mousewheel.
2962 Removed some debugging prints.
2963
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002964- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002965
Fred Drake67233bc2000-09-26 16:40:27 +00002966- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002967 which works around a bug in Norton AntiVirus 2000 that leads directly
2968 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002969
2970- xml: New version detection code allows PyXML to override standard
2971 XML package if PyXML version is greater than 0.6.1.
2972
Fred Drake64bb3802000-09-26 16:21:35 +00002973- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2974 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2975 tree only for nodes which are sufficiently interesting to a specific
2976 application. Does not provide the HTML-specific extensions. Still
2977 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002978
Fred Drake64bb3802000-09-26 16:21:35 +00002979- xml.sax: SAX 2 support for Python, including all the handler
2980 interfaces needed to process XML 1.0 compliant XML. Some
2981 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002982
Fred Drake64bb3802000-09-26 16:21:35 +00002983- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2984 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002985
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002986
Jeremy Hylton1b618592000-09-26 05:32:36 +00002987C API
2988
2989- Add three new convenience functions for module initialization --
2990 PyModule_AddObject(), PyModule_AddIntConstant(), and
2991 PyModule_AddStringConstant().
2992
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002993- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002994 removed and add #error to Python.h if NULL isn't defined after
2995 #include of stdio.h.
2996
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002997- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002998 backwards compatibility (at the source level) with old extensions.
2999
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003000- A wrapper API was added for signal() and sigaction(). Instead of
3001 either function, always use PyOS_getsig() to get a signal handler
3002 and PyOS_setsig() to set one. A new convenience typedef
3003 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003004
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003005- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003006 internal data buffer and size of a string object -- or the default
3007 encoded version of a Unicode object.
3008
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003009- PyString_Size() and PyString_AsString() accept Unicode objects.
3010
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003011- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003012 exists). INT_MAX and LONG_MAX will always be defined, even if
3013 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003014
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003015- PyFloat_FromString takes a second argument, pend, that was
3016 effectively useless. It is now officially useless but preserved for
3017 backwards compatibility. If the pend argument is not NULL, *pend is
3018 set to NULL.
3019
3020- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3021 for the attribute name. See note on getattr() above.
3022
3023- A few bug fixes to argument processing for Unicode.
3024 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3025 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3026 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003027 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003028
3029- Py_BuildValue accepts B format (for bgen-generated code).
3030
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003031
Jeremy Hylton1b618592000-09-26 05:32:36 +00003032Internals
3033
3034- On Unix, fix code for finding Python installation directory so that
3035 it works when argv[0] is a relative path.
3036
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003037- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003038 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003039 rather than by generating a copy of the object.
3040
Tim Peters482c0212000-09-26 06:33:09 +00003041- Several of the internal Unicode tables are much smaller now, and
3042 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003043
Jeremy Hylton97693b02000-09-26 17:42:51 +00003044- In the garbage collector: Fixed bug in collection of tuples. Fixed
3045 bug that caused some instances to be removed from the container set
3046 while they were still live. Fixed parsing in gc.set_debug() for
3047 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003048
3049- Fixed refcount problem in instance deallocation that only occurred
3050 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3051
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003052- On Windows, getpythonregpath is now protected against null data in
3053 registry key.
3054
3055- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003056 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003057
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003058
Jeremy Hylton1b618592000-09-26 05:32:36 +00003059Build and platform-specific issues
3060
3061- Better support of GNU Pth via --with-pth configure option.
3062
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003063- Python/C API now properly exposed to dynamically-loaded extension
3064 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003065
3066- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3067 Don't define MS_SYNC to be zero when it is undefined. Added missing
3068 prototypes in posixmodule.c.
3069
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003070- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003071 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003072
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003073- Fix largefile support on older NetBSD systems and OpenBSD by adding
3074 define for TELL64.
3075
3076
3077Tools and other miscellany
3078
3079- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3080
3081- freeze: The modulefinder now works with 2.0 opcodes.
3082
Tim Petersa3a3a032000-11-30 05:22:44 +00003083- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003084 Move hackery of sys.argv until after the Tk instance has been
3085 created, which allows the application-specific Tkinter
3086 initialization to be executed if present; also pass an explicit
3087 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003088
Jeremy Hylton1b618592000-09-26 05:32:36 +00003089
3090What's new in 2.0 beta 1?
3091=========================
3092
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003093Source Incompatibilities
3094------------------------
3095
3096None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3097such as single-argument append(), connect() and bind(), and changes to
3098str(long) and repr(float).
3099
3100
3101Binary Incompatibilities
3102------------------------
3103
3104- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3105with Python 2.0; these extensions will have to be rebuilt for Python
31062.0.
3107
3108- On Windows, attempting to import a third party extension built for
3109Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3110can do about this. Check your PYTHONPATH environment variable!
3111
3112- Python bytecode files (*.pyc and *.pyo) are not compatible between
3113releases.
3114
3115
3116Overview of Changes Since 1.6
3117-----------------------------
3118
3119There are many new modules (including brand new XML support through
3120the xml package, and i18n support through the gettext module); a list
3121of all new modules is included below. Lots of bugs have been fixed.
3122
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003123The process for making major new changes to the language has changed
3124since Python 1.6. Enhancements must now be documented by a Python
3125Enhancement Proposal (PEP) before they can be accepted.
3126
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003127There are several important syntax enhancements, described in more
3128detail below:
3129
3130 - Augmented assignment, e.g. x += 1
3131
3132 - List comprehensions, e.g. [x**2 for x in range(10)]
3133
3134 - Extended import statement, e.g. import Module as Name
3135
3136 - Extended print statement, e.g. print >> file, "Hello"
3137
3138Other important changes:
3139
3140 - Optional collection of cyclical garbage
3141
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003142Python Enhancement Proposal (PEP)
3143---------------------------------
3144
3145PEP stands for Python Enhancement Proposal. A PEP is a design
3146document providing information to the Python community, or describing
3147a new feature for Python. The PEP should provide a concise technical
3148specification of the feature and a rationale for the feature.
3149
3150We intend PEPs to be the primary mechanisms for proposing new
3151features, for collecting community input on an issue, and for
3152documenting the design decisions that have gone into Python. The PEP
3153author is responsible for building consensus within the community and
3154documenting dissenting opinions.
3155
3156The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003157
3158Augmented Assignment
3159--------------------
3160
3161This must have been the most-requested feature of the past years!
3162Eleven new assignment operators were added:
3163
Guido van Rossume905e952000-09-05 12:42:46 +00003164 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003165
3166For example,
3167
3168 A += B
3169
3170is similar to
3171
3172 A = A + B
3173
3174except that A is evaluated only once (relevant when A is something
3175like dict[index].attr).
3176
3177However, if A is a mutable object, A may be modified in place. Thus,
3178if A is a number or a string, A += B has the same effect as A = A+B
3179(except A is only evaluated once); but if a is a list, A += B has the
3180same effect as A.extend(B)!
3181
3182Classes and built-in object types can override the new operators in
3183order to implement the in-place behavior; the not-in-place behavior is
3184used automatically as a fallback when an object doesn't implement the
3185in-place behavior. For classes, the method name is derived from the
3186method name for the corresponding not-in-place operator by inserting
3187an 'i' in front of the name, e.g. __iadd__ implements in-place
3188__add__.
3189
3190Augmented assignment was implemented by Thomas Wouters.
3191
3192
3193List Comprehensions
3194-------------------
3195
3196This is a flexible new notation for lists whose elements are computed
3197from another list (or lists). The simplest form is:
3198
3199 [<expression> for <variable> in <sequence>]
3200
Guido van Rossum56db0952000-09-06 23:34:25 +00003201For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003202This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003203
3204You can also add a condition:
3205
3206 [<expression> for <variable> in <sequence> if <condition>]
3207
3208For example, [w for w in words if w == w.lower()] would yield the list
3209of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003210than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003211
3212You can also have nested for loops and more than one 'if' clause. For
3213example, here's a function that flattens a sequence of sequences::
3214
3215 def flatten(seq):
3216 return [x for subseq in seq for x in subseq]
3217
3218 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3219
3220This prints
3221
3222 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3223
3224List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003225Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003226
3227
3228Extended Import Statement
3229-------------------------
3230
3231Many people have asked for a way to import a module under a different
3232name. This can be accomplished like this:
3233
3234 import foo
3235 bar = foo
3236 del foo
3237
3238but this common idiom gets old quickly. A simple extension of the
3239import statement now allows this to be written as follows:
3240
3241 import foo as bar
3242
3243There's also a variant for 'from ... import':
3244
3245 from foo import bar as spam
3246
3247This also works with packages; e.g. you can write this:
3248
3249 import test.regrtest as regrtest
3250
3251Note that 'as' is not a new keyword -- it is recognized only in this
3252context (this is only possible because the syntax for the import
3253statement doesn't involve expressions).
3254
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003255Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003256
3257
3258Extended Print Statement
3259------------------------
3260
3261Easily the most controversial new feature, this extension to the print
3262statement adds an option to make the output go to a different file
3263than the default sys.stdout.
3264
3265For example, to write an error message to sys.stderr, you can now
3266write:
3267
3268 print >> sys.stderr, "Error: bad dog!"
3269
3270As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003271evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003272
3273 print >> None, "Hello world"
3274
3275is equivalent to
3276
3277 print "Hello world"
3278
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003279Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003280
3281
3282Optional Collection of Cyclical Garbage
3283---------------------------------------
3284
3285Python is now equipped with a garbage collector that can hunt down
3286cyclical references between Python objects. It's no replacement for
3287reference counting; in fact, it depends on the reference counts being
3288correct, and decides that a set of objects belong to a cycle if all
3289their reference counts can be accounted for from their references to
3290each other. This devious scheme was first proposed by Eric Tiedemann,
3291and brought to implementation by Neil Schemenauer.
3292
3293There's a module "gc" that lets you control some parameters of the
3294garbage collection. There's also an option to the configure script
3295that lets you enable or disable the garbage collection. In 2.0b1,
3296it's on by default, so that we (hopefully) can collect decent user
3297experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003298performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003299off by default in the final 2.0 release.
3300
3301
3302Smaller Changes
3303---------------
3304
3305A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3306map(None, seq1, seq2, ...) when the sequences have the same length;
3307i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3308the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003309zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003310
3311sys.version_info is a tuple (major, minor, micro, level, serial).
3312
3313Dictionaries have an odd new method, setdefault(key, default).
3314dict.setdefault(key, default) returns dict[key] if it exists; if not,
3315it sets dict[key] to default and returns that value. Thus:
3316
3317 dict.setdefault(key, []).append(item)
3318
3319does the same work as this common idiom:
3320
3321 if not dict.has_key(key):
3322 dict[key] = []
3323 dict[key].append(item)
3324
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003325There are two new variants of SyntaxError that are raised for
3326indentation-related errors: IndentationError and TabError.
3327
3328Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3329escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003330
3331The limits on the size of expressions and file in Python source code
3332have been raised from 2**16 to 2**32. Previous versions of Python
3333were limited because the maximum argument size the Python VM accepted
3334was 2**16. This limited the size of object constructor expressions,
3335e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3336limit was raised thanks to a patch by Charles Waldman that effectively
3337fixes the problem. It is now much more likely that you will be
3338limited by available memory than by an arbitrary limit in Python.
3339
3340The interpreter's maximum recursion depth can be modified by Python
3341programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3342limit is the maximum number of recursive calls that can be made by
3343Python code. The limit exists to prevent infinite recursion from
3344overflowing the C stack and causing a core dump. The default value is
33451000. The maximum safe value for a particular platform can be found
3346by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003347
3348New Modules and Packages
3349------------------------
3350
3351atexit - for registering functions to be called when Python exits.
3352
3353imputil - Greg Stein's alternative API for writing custom import
3354hooks.
3355
3356pyexpat - an interface to the Expat XML parser, contributed by Paul
3357Prescod.
3358
3359xml - a new package with XML support code organized (so far) in three
3360subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3361would fill a volume. There's a special feature whereby a
3362user-installed package named _xmlplus overrides the standard
3363xmlpackage; this is intended to give the XML SIG a hook to distribute
3364backwards-compatible updates to the standard xml package.
3365
3366webbrowser - a platform-independent API to launch a web browser.
3367
3368
Guido van Rossume905e952000-09-05 12:42:46 +00003369Changed Modules
3370---------------
3371
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003372array -- new methods for array objects: count, extend, index, pop, and
3373remove
3374
3375binascii -- new functions b2a_hex and a2b_hex that convert between
3376binary data and its hex representation
3377
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003378calendar -- Many new functions that support features including control
3379over which day of the week is the first day, returning strings instead
3380of printing them. Also new symbolic constants for days of week,
3381e.g. MONDAY, ..., SUNDAY.
3382
3383cgi -- FieldStorage objects have a getvalue method that works like a
3384dictionary's get method and returns the value attribute of the object.
3385
3386ConfigParser -- The parser object has new methods has_option,
3387remove_section, remove_option, set, and write. They allow the module
3388to be used for writing config files as well as reading them.
3389
3390ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003391optionally support the RFC 959 REST command.
3392
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003393gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003394
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003395httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3396the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003397
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003398locale -- implement getdefaultlocale for Win32 and Macintosh
3399
3400marshal -- no longer dumps core when marshaling deeply nested or
3401recursive data structures
3402
3403os -- new functions isatty, seteuid, setegid, setreuid, setregid
3404
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003405os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3406support under Unix.
3407
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003408os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003409
3410os.path -- fix semantics of os.path.commonprefix
3411
3412smtplib -- support for sending very long messages
3413
3414socket -- new function getfqdn()
3415
3416readline -- new functions to read, write and truncate history files.
3417The readline section of the library reference manual contains an
3418example.
3419
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003420select -- add interface to poll system call
3421
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003422shutil -- new copyfileobj function
3423
3424SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3425HTTP server.
3426
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003427Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003428
3429urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003430e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003431
3432whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003433
3434
3435Obsolete Modules
3436----------------
3437
3438None. However note that 1.6 made a whole slew of modules obsolete:
3439stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3440poly, zmod, strop, util, whatsound.
3441
3442
3443Changed, New, Obsolete Tools
3444----------------------------
3445
Tim Peters8b092332000-09-05 20:15:25 +00003446None.
Guido van Rossume905e952000-09-05 12:42:46 +00003447
3448
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003449C-level Changes
3450---------------
3451
3452Several cleanup jobs were carried out throughout the source code.
3453
3454All C code was converted to ANSI C; we got rid of all uses of the
3455Py_PROTO() macro, which makes the header files a lot more readable.
3456
3457Most of the portability hacks were moved to a new header file,
3458pyport.h; several other new header files were added and some old
3459header files were removed, in an attempt to create a more rational set
3460of header files. (Few of these ever need to be included explicitly;
3461they are all included by Python.h.)
3462
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003463Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003464and Win64, especially for the new Intel Itanium processor. Mick also
3465added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003466
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003467The C APIs to return an object's size have been update to consistently
3468use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3469previous versions, the abstract interfaces used PyXXX_Length and the
3470concrete interfaces used PyXXX_Size. The old names,
3471e.g. PyObject_Length, are still available for backwards compatibility
3472at the API level, but are deprecated.
3473
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003474The PyOS_CheckStack function has been implemented on Windows by
3475Fredrik Lundh. It prevents Python from failing with a stack overflow
3476on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003477
3478The GC changes resulted in creation of two new slots on object,
3479tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003480the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003481
3482The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003483C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003484
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003485PyErr_Format has been updated to automatically calculate the size of
3486the buffer needed to hold the formatted result string. This change
3487prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003488
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003489New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003490
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003491PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3492that are the same as their non-Ex counterparts except they take an
3493extra flag argument that tells them to close the file when done.
3494
3495XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003496
Tim Peters8b092332000-09-05 20:15:25 +00003497
3498Windows Changes
3499---------------
3500
3501New popen2/popen3/peopen4 in os module (see Changed Modules above).
3502
3503os.popen is much more usable on Windows 95 and 98. See Microsoft
3504Knowledge Base article Q150956. The Win9x workaround described there
3505is implemented by the new w9xpopen.exe helper in the root of your
3506Python installation. Note that Python uses this internally; it is not
3507a standalone program.
3508
3509Administrator privileges are no longer required to install Python
3510on Windows NT or Windows 2000. If you have administrator privileges,
3511Python's registry info will be written under HKEY_LOCAL_MACHINE.
3512Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003513under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003514uses of Python, but will prevent some advanced uses from working
3515(for example, running a Python script as an NT service, or possibly
3516from CGI).
3517
3518[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3519installer; instead, it installs the needed Tcl/Tk files directly in the
3520Python directory. If you already have a Tcl/Tk installation, this
3521wastes some disk space (about 4 Megs) but avoids problems with
3522conflicting Tcl/Tk installations, and makes it much easier for Python
3523to ensure that Tcl/Tk can find all its files.
3524
3525[This was new in 1.6] The Windows installer now installs by default in
3526\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3527
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003528
3529Updates to the changes between 1.5.2 and 1.6
3530--------------------------------------------
3531
3532The 1.6 NEWS file can't be changed after the release is done, so here
3533is some late-breaking news:
3534
3535New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3536and changes to getlocale() and setlocale().
3537
3538The new module is now enabled per default.
3539
3540It is not true that the encodings codecs cannot be used for normal
3541strings: the string.encode() (which is also present on 8-bit strings
3542!) allows using them for 8-bit strings too, e.g. to convert files from
3543cp1252 (Windows) to latin-1 or vice-versa.
3544
3545Japanese codecs are available from Tamito KAJIYAMA:
3546http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3547
3548
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003549======================================================================