blob: 6dd99579fc659c2975734e5f3d2b51d8afaf4413 [file] [log] [blame]
Tim Peterscffed4b2001-11-29 03:26:37 +00001What's New in Python 2.2c1
Tim Petersb3c9af12001-11-17 00:21:57 +00002XXX Release date: ??-Dec-2001 XXX
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum33bab012001-12-05 22:45:48 +00007- Fixed a leak: instance variables declared with __slots__ were never
8 deleted!
9
Guido van Rossum4b800852001-12-03 00:54:52 +000010- The "delete attribute" method of descriptor objects is called
11 __delete__, not __del__. In previous releases, it was mistakenly
12 called __del__, which created an unfortunate overloading condition
13 with finalizers. (The "get attribute" and "set attribute" methods
14 are still called __get__ and __set__, respectively.)
15
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000016- Some subtle issues with the super built-in were fixed:
17
18 (a) When super itself is subclassed, its __get__ method would still
19 return an instance of the base class (i.e., of super).
20
21 (b) super(C, C()).__class__ would return C rather than super. This
22 is confusing. To fix this, I decided to change the semantics of
23 super so that it only applies to code attributes, not to data
24 attributes. After all, overriding data attributes is not
25 supported anyway.
26
27 (c) The __get__ method didn't check whether the argument was an
28 instance of the type used in creation of the super instance.
29
Guido van Rossumcd7b7d62001-12-04 21:02:07 +000030- Previously, hash() of an instance of a subclass of a mutable type
31 (list or dictionary) would return some value, rather than raising
32 TypeError. This has been fixed. Also, directly calling
33 dict.__hash__ and list.__hash__ now raises the same TypeError
34 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000035
Guido van Rossumd331cb52001-12-05 19:46:42 +000036- New-style objects now support deleting their __dict__. This is for
37 all intents and purposes equivalent to assigning a brand new empty
38 dictionary, but saves space if the object is not used further.
39
Tim Petersb3c9af12001-11-17 00:21:57 +000040Core and builtins
41
Tim Peters3caca232001-12-06 06:23:26 +000042- -Qnew now works as documented in PEP 238: when -Qnew is passed on
43 the command line, all occurrences of "/" use true division instead
44 of classic division. See the PEP for details. Note that "all"
45 means all instances in library and 3rd-party modules, as well as in
46 your own code. As the PEP says, -Qnew is intended for use only in
47 educational environments with control over the libraries in use.
48
Tim Petersb3c9af12001-11-17 00:21:57 +000049Extension modules
50
Martin v. Löwis560da622001-11-24 09:24:51 +000051- gc.get_referents was renamed to gc.get_referrers.
52
Tim Petersb3c9af12001-11-17 00:21:57 +000053Library
54
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +000055- webbrowser defaults to netscape.exe on OS/2 now.
56
Martin v. Löwis652e1912001-11-25 14:50:56 +000057- Tix.ResizeHandle exposes detach_widget, hide, and show.
58
Martin v. Löwis714d2e22001-12-02 12:26:03 +000059- The charset alias windows_1252 has been added.
60
Tim Petersb3c9af12001-11-17 00:21:57 +000061Tools/Demos
62
63Build
64
Jack Jansen1999ef42001-12-06 21:47:20 +000065- It is no longer necessary to use --with-suffix when building on a
66 case-insensitive file system (such as Mac OS X HFS+). In the build
67 directory an extension is used, but not in the installed python.
68
Tim Petersb3c9af12001-11-17 00:21:57 +000069C API
70
Tim Peterscffed4b2001-11-29 03:26:37 +000071- PyArg_ParseTupleAndKeywords() requires that the number of entries in
72 the keyword list equals the number of argument specifiers. This
73 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
74 dump core in some bad cases. This has been repaired. As a result,
75 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
76 previously went unchallenged.
77
Tim Petersb3c9af12001-11-17 00:21:57 +000078New platforms
79
80Tests
81
82Windows
83
84Mac
85
Jack Jansenffa260f2001-12-06 21:14:00 +000086- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
87 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +000088
Tim Peters84362bc2001-10-19 17:55:30 +000089What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000090Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000091===========================
92
93Type/class unification and new-style classes
94
Guido van Rossum3d27df02001-11-15 20:27:54 +000095- Multiple inheritance mixing new-style and classic classes in the
96 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000097
98 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000099 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000100
101 The MRO (method resolution order) for each base class is respected
102 according to its kind, but the MRO for the derived class is computed
103 using new-style MRO rules if any base clase is a new-style class.
104 This needs to be documented.
105
Tim Petersa427a2b2001-10-29 22:25:45 +0000106- The new builtin dictionary() constructor, and dictionary type, have
107 been renamed to dict. This reflects a decade of common usage.
108
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000109- dict() now accepts an iterable object producing 2-sequences. For
110 example, dict(d.items()) == d for any dictionary d. The argument,
111 and the elements of the argument, can be any iterable objects.
112
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000113- New-style classes can now have a __del__ method, which is called
114 when the instance is deleted (just like for classic classes).
115
Guido van Rossum12d955c2001-10-26 14:56:06 +0000116- Assignment to object.__dict__ is now possible, for objects that are
117 instances of new-style classes that have a __dict__ (unless the base
118 class forbids it).
119
Guido van Rossumc8e56452001-10-22 00:43:43 +0000120- Methods of built-in types now properly check for keyword arguments
121 (formerly these were silently ignored). The only built-in methods
122 that take keyword arguments are __call__, __init__ and __new__.
123
Guido van Rossum86443212001-10-27 22:28:54 +0000124- The socket function has been converted to a type; see below.
125
Tim Peters84362bc2001-10-19 17:55:30 +0000126Core and builtins
127
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000128- Assignment to __debug__ raises SyntaxError at compile-time. This
129 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000130 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000131
Guido van Rossum12d955c2001-10-26 14:56:06 +0000132- Clarified the error messages for unsupported operands to an operator
133 (like 1 + '').
134
Tim Peters84362bc2001-10-19 17:55:30 +0000135Extension modules
136
Tim Peters5ebfd362001-11-13 23:11:19 +0000137- mmap has a new keyword argument, "access", allowing a uniform way for
138 both Windows and Unix users to create read-only, write-through and
139 copy-on-write memory mappings. This was previously possible only on
140 Unix. A new keyword argument was required to support this in a
141 uniform way because the mmap() signuatures had diverged across
142 platforms. Thanks to Jay T Miller for repairing this!
143
Tim Peters169ded02001-11-03 19:57:21 +0000144- By default, the gc.garbage list now contains only those instances in
145 unreachable cycles that have __del__ methods; in 2.1 it contained all
146 instances in unreachable cycles. "Instances" here has been generalized
147 to include instances of both new-style and old-style classes.
148
Guido van Rossum12d955c2001-10-26 14:56:06 +0000149- The socket module defines a new method for socket objects,
150 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000151 send() until all data has been sent. Also, the socket function has
152 been converted to a subclassable type, like list and tuple (etc.)
153 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000154
155- Various bugfixes to the curses module. There is now a test suite
156 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000157
Guido van Rossum692adf12001-10-30 03:03:03 +0000158- binascii.b2a_base64 no longer places an arbitrary restriction of 57
159 bytes on its input.
160
Tim Peters84362bc2001-10-19 17:55:30 +0000161Library
162
Tim Peters5ebfd362001-11-13 23:11:19 +0000163- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000164 convenience function.
165
Tim Peters75335872001-11-03 19:35:43 +0000166- Symbolic group names in regular expressions must be unique. For
167 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
168 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000169 Python 2.2 detects this error at regexp compilation time;
170 previously, the error went undetected, and results were
171 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
172 pattern.subn() methods have been rewritten in C. Also, an
173 experimental function/method finditer() has been added, which works
174 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000175
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000176- Tix exposes more commands through the classes DirSelectBox,
177 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
178 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
179 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
180
Tim Peters98791af2001-10-23 01:59:54 +0000181- Traceback objects are now scanned by cyclic garbage collection, so
182 cycles created by casual use of sys.exc_info() no longer cause
183 permanent memory leaks (provided garbage collection is enabled).
184
Guido van Rossum49192142001-10-24 20:51:44 +0000185- os.extsep -- a new variable needed by the RISCOS support. It is the
186 separator used by extensions, and is '.' on all platforms except
187 RISCOS, where it is '/'. There is no need to use this variable
188 unless you have a masochistic desire to port your code to RISCOS.
189
Barry Warsaw012852b2001-11-16 16:17:27 +0000190- mimetypes.py has optional support for non-standard, but commonly
191 found types. guess_type() and guess_extension() now accept an
192 optional `strict' flag, defaulting to true, which controls whether
193 recognize non-standard types or not. A few non-standard types we
194 know about have been added. Also, when run as a script, there are
195 new -l and -e options.
196
197- statcache is now deprecated.
198
199- email.Utils.formatdate() now produces the preferred RFC 2822 style
200 dates with numeric timezones (it used to produce obsolete dates
201 hard coded to "GMT" timezone). An optional `localtime' flag is
202 added to produce dates in the local timezone, with daylight savings
203 time properly taken into account.
204
205- In pickle and cPickle, instead of masking errors in load() by
206 transforming them into SystemError, we let the original exception
207 propagate out. Also, implement support for __safe_for_unpickling__
208 in pickle, as it already was supported in cPickle.
209
Tim Peters84362bc2001-10-19 17:55:30 +0000210Tools/Demos
211
212Build
213
Barry Warsaw012852b2001-11-16 16:17:27 +0000214- The dbm module is built using libdb1 if available. The bsddb module
215 is built with libdb3 if available.
216
217- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
218
Tim Peters84362bc2001-10-19 17:55:30 +0000219C API
220
Tim Peters1fc240e2001-10-26 05:06:50 +0000221- New function PySequence_Fast_GET_SIZE() returns the size of a non-
222 NULL result from PySequence_Fast(), more quickly than calling
223 PySequence_Size().
224
Barry Warsaw012852b2001-11-16 16:17:27 +0000225- New argument unpacking function PyArg_UnpackTuple() added.
226
227- New functions PyObject_CallFunctionObjArgs() and
228 PyObject_CallMethodObjArgs() have been added to make it more
229 convenient and efficient to call functions and methods from C.
230
231- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
232 possible that this will propagate errors it didn't before.
233
234- New function PyObject_CheckReadBuffer(), which returns true if its
235 argument supports the single-segment readable buffer interface.
236
Tim Peters84362bc2001-10-19 17:55:30 +0000237New platforms
238
Guido van Rossum86443212001-10-27 22:28:54 +0000239- We've finally confirmed that this release builds on HP-UX 11.00,
240 *with* threads, and passes the test suite.
241
Tim Peters7a33d8b2001-11-05 02:51:07 +0000242- Thanks to a series of patches from Michael Muller, Python may build
243 again under OS/2 Visual Age C++.
244
Guido van Rossum49192142001-10-24 20:51:44 +0000245- Updated RISCOS port by Dietmar Schwertberger.
246
Tim Peters84362bc2001-10-19 17:55:30 +0000247Tests
248
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000249- Added a test script for the curses module. It isn't run automatically;
250 regrtest.py must be run with '-u curses' to enable it.
251
Tim Peters84362bc2001-10-19 17:55:30 +0000252Windows
253
Barry Warsaw012852b2001-11-16 16:17:27 +0000254Mac
255
256- PythonScript has been moved to unsupported and is slated to be
257 removed completely in the next release.
258
259- It should now be possible to build applets that work on both OS9 and
260 OSX.
261
262- The core is now linked with CoreServices not Carbon; as a side
263 result, default 8bit encoding on OSX is now ASCII.
264
265- Python should now build on OSX 10.1.1
266
Tim Peters84362bc2001-10-19 17:55:30 +0000267
Tim Petersabf925f2001-09-28 21:53:42 +0000268What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000269Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000270===========================
271
272Type/class unification and new-style classes
273
Guido van Rossum687ae002001-10-15 22:03:32 +0000274- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000275 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000276 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000277 remains: the __dict__ of a new-style class is a read-only proxy; you
278 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000279 __defined__ attribute of new-style types no longer exists, for lack
280 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000281 future a __cache__ may be resurrected with a similar function, if I
282 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000283
Tim Peters1c9ca872001-10-04 06:43:12 +0000284- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
285 always returned None, even when there was a class docstring).
286
287- doctest now finds and runs docstrings attached to new-style classes,
288 class methods, static methods, and properties.
289
Guido van Rossum9074ef62001-10-16 21:34:49 +0000290Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000291
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000292- A very subtle syntactical pitfall in list comprehensions was fixed.
293 For example: [a+b for a in 'abc', for b in 'def']. The comma in
294 this example is a mistake. Previously, this would silently let 'a'
295 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
296 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
297 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
298 Note that [a for a in <singleton>] is a convoluted way to say
299 [<singleton>] anyway, so it's not like any expressiveness is lost.
300
Guido van Rossum9074ef62001-10-16 21:34:49 +0000301- getattr(obj, name, default) now only catches AttributeError, as
302 documented, rather than returning the default value for all
303 exceptions (which could mask bugs in a __getattr__ hook, for
304 example).
305
Fred Drakecb7a6b52001-10-22 18:41:51 +0000306- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000307 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000308 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000309 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000310
Guido van Rossum1c486092001-10-19 02:05:35 +0000311- unicode(obj) now behaves more like str(obj), accepting arbitrary
312 objects, and calling a __unicode__ method if it exists.
313 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000314 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000315
Barry Warsawf6fb1712001-10-19 05:35:40 +0000316- isinstance() now allows any object as the first argument and a
317 class, a type or something with a __bases__ tuple attribute for the
318 second argument. The second argument may also be a tuple of a
319 class, type, or something with __bases__, in which case isinstance()
320 will return true if the first argument is an instance of any of the
321 things contained in the second argument tuple. E.g.
322
323 isinstance(x, (A, B))
324
325 returns true if x is an instance of A or B.
326
Guido van Rossum9074ef62001-10-16 21:34:49 +0000327Extension modules
328
329- thread.start_new_thread() now returns the thread ID (previously None).
330
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000331- binascii has now two quopri support functions, a2b_qp and b2a_qp.
332
Guido van Rossumc524d952001-10-19 01:31:59 +0000333- readline now supports setting the startup_hook and the
334 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000335
Guido van Rossumc524d952001-10-19 01:31:59 +0000336- os and posix supports chroot(), setgroups() and unsetenv() where
337 available. The stat(), fstat(), statvfs() and fstatvfs() functions
338 now return "pseudo-sequences" -- the various fields can now be
339 accessed as attributes (e.g. os.stat("/").st_mtime) but for
340 backwards compatibility they also behave as a fixed-length sequence.
341 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000342 attributes.
343
344- time: localtime(), gmtime() and strptime() now return a
345 pseudo-sequence similar to the os.stat() return value, with
346 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000347
Guido van Rossum9074ef62001-10-16 21:34:49 +0000348- Decompression objects in the zlib module now accept an optional
349 second parameter to decompress() that specifies the maximum amount
350 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000351
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000352- optional SSL support in the socket module now exports OpenSSL
353 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
354 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000355 automatically seed its PRNG. Also, the keyfile and certfile
356 arguments to socket.ssl() are now optional.
357
358- posixmodule (and by extension, the os module on POSIX platforms) now
359 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000360
Guido van Rossum9074ef62001-10-16 21:34:49 +0000361Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000362
Tim Peters7402f792001-10-02 03:53:41 +0000363- doctest now excludes functions and classes not defined by the module
364 being tested, thanks to Tim Hochberg.
365
Fred Drakecb7a6b52001-10-22 18:41:51 +0000366- HotShot, a new profiler implemented using a C-based callback, has
367 been added. This substantially reduces the overhead of profiling,
368 but it is still quite preliminary. Support modules and
369 documentation will be added in upcoming releases (before 2.2 final).
370
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000371- profile now produces correct output in situations where an exception
372 raised in Python is cleared by C code (e.g. hasattr()). This used
373 to cause wrong output, including spurious claims of recursive
374 functions and attribution of time spent to the wrong function.
375
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000376 The code and documentation for the derived OldProfile and HotProfile
377 profiling classes was removed. The code hasn't worked for years (if
378 you tried to use them, they raised exceptions). OldProfile
379 intended to reproduce the behavior of the profiler Python used more
380 than 7 years ago, and isn't interesting anymore. HotProfile intended
381 to provide a faster profiler (but producing less information), and
382 that's a worthy goal we intend to meet via a different approach (but
383 without losing information).
384
Tim Peterscce092d2001-10-09 05:31:56 +0000385- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000386 a much better system-specific calibration constant. The constant can
387 now be specified in an instance constructor, or as a Profile class or
388 instance variable, instead of by editing profile.py's source code.
389 Calibration must still be done manually (see the docs for the profile
390 module).
391
392 Note that Profile.calibrate() must be overriden by subclasses.
393 Improving the accuracy required exploiting detailed knowledge of
394 profiler internals; the earlier method abstracted away the details
395 and measured a simplified model instead, but consequently computed
396 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000397
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000398- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000399 which indicates whether output is intended for the header 'Q'
400 encoding.
401
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000402- The SocketServer.ThreadingMixIn class now closes the request after
403 finish_request() returns. (Not when it errors out though.)
404
Barry Warsawf6fb1712001-10-19 05:35:40 +0000405- The nntplib module's NNTP.body() method has grown a `file' argument
406 to allow saving the message body to a file.
407
408- The email package has added a class email.Parser.HeaderParser which
409 only parses headers and does not recurse into the message's body.
410 Also, the module/class MIMEAudio has been added for representing
411 audio data (contributed by Anthony Baxter).
412
413- ftplib should be able to handle files > 2GB.
414
415- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
416 ON, and OFF.
417
Fred Drakecb7a6b52001-10-22 18:41:51 +0000418- xml.dom.minidom NodeList objects now support the length attribute
419 and item() method as required by the DOM specifications.
420
Guido van Rossumed554f62001-10-02 23:15:37 +0000421Tools/Demos
422
423- Demo/dns was removed. It no longer serves any purpose; a package
424 derived from it is now maintained by Anthony Baxter, see
425 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000426
Barry Warsawf6fb1712001-10-19 05:35:40 +0000427- The freeze tool has been made more robust, and two new options have
428 been added: -X and -E.
429
Tim Petersabf925f2001-09-28 21:53:42 +0000430Build
431
Barry Warsawf6fb1712001-10-19 05:35:40 +0000432- configure will use CXX in LINKCC if CXX is used to build main() and
433 the system requires to link a C++ main using the C++ compiler.
434
Tim Petersabf925f2001-09-28 21:53:42 +0000435C API
436
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000437- The documentation for the tp_compare slot is updated to require that
438 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
439 not correct. This is not yet enforced but will be enforced in
440 Python 2.3; even later, we may use -2 to indicate errors and +2 for
441 "NotImplemented". Right now, -1 should be used for an error return.
442
Tim Petersd38b1c72001-09-30 05:09:37 +0000443- PyLong_AsLongLong() now accepts int (as well as long) arguments.
444 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
445 as long) arguments.
446
Guido van Rossum3c288632001-10-16 21:13:49 +0000447- PyThread_start_new_thread() now returns a long int giving the thread
448 ID, if one can be calculated; it returns -1 for error, 0 if no
449 thread ID is calculated (this is an incompatible change, but only
450 the thread module used this API). This code has only really been
451 tested on Linux and Windows; other platforms please beware (and
452 report any bugs or strange behavior).
453
Guido van Rossum1c486092001-10-19 02:05:35 +0000454- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
455 input.
456
Tim Petersabf925f2001-09-28 21:53:42 +0000457New platforms
458
459Tests
460
461Windows
462
Tim Peters04cf1d32001-10-09 22:39:40 +0000463- Installer: If you install IDLE, and don't disable file-extension
464 registration, a new "Edit with IDLE" context (right-click) menu entry
465 is created for .py and .pyw files.
466
Tim Peters1ce3cf72001-10-01 17:58:40 +0000467- The signal module now supports SIGBREAK on Windows, thanks to Steven
468 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
469 action remains to call Win32 ExitProcess(). This can be changed via
470 signal.signal(). For example:
471
472 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
473 # (SIGINT) behavior.
474 import signal
475 signal.signal(signal.SIGBREAK,
476 signal.default_int_handler)
477
478 try:
479 while 1:
480 pass
481 except KeyboardInterrupt:
482 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
483 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
484 # program without the possibility for any Python-level cleanup).
485 print "Clean exit"
486
Tim Petersabf925f2001-09-28 21:53:42 +0000487
Tim Petersb07352e2001-09-08 01:25:47 +0000488What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000489Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000490===========================
491
Guido van Rossum808eea72001-09-25 04:15:41 +0000492Type/class unification and new-style classes
493
494- pydoc and inspect are now aware of new-style classes;
495 e.g. help(list) at the interactive prompt now shows proper
496 documentation for all operations on list objects.
497
498- Applications using Jim Fulton's ExtensionClass module can now safely
499 be used with Python 2.2. In particular, Zope 2.4.1 now works with
500 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
501 examples also work again. It is hoped that Gtk and Boost also work
502 with 2.2a4 and beyond. (If you can confirm this, please write
503 webmaster@python.org; if there are still problems, please open a bug
504 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000505
Tim Peters66c1a522001-09-24 21:17:50 +0000506- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
507 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
508 in the constructed property object. fget, fset and fdel weren't
509 discoverable from Python in 2.2a3. __doc__ is new, and allows to
510 associate a docstring with a property.
511
Guido van Rossum808eea72001-09-25 04:15:41 +0000512- Comparison overloading is now more completely implemented. For
513 example, a str subclass instance can properly be compared to a str
514 instance, and it can properly overload comparison. Ditto for most
515 other built-in object types.
516
517- The repr() of new-style classes has changed; instead of <type
518 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
519 *except* for built-in types, which are still rendered as <type
520 'Foo'> (to avoid upsetting existing code that might parse or
521 otherwise rely on repr() of certain type objects).
522
523- The repr() of new-style objects is now always <Foo object at XXX>;
524 previously, it was sometimes <Foo instance at XXX>.
525
526- For new-style classes, what was previously called __getattr__ is now
527 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000528 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000529 one in classic classes is defined which is called only if regular
530 attribute access raises AttributeError; to catch *all* attribute
531 access, you can use __getattribute__ (for new-style classes). If
532 both are defined, __getattribute__ is called first, and if it raises
533 AttributeError, __getattr__ is called.
534
535- The __class__ attribute of new-style objects can be assigned to.
536 The new class must have the same C-level object layout as the old
537 class.
538
539- The builtin file type can be subclassed now. In the usual pattern,
540 "file" is the name of the builtin type, and file() is a new builtin
541 constructor, with the same signature as the builtin open() function.
542 file() is now the preferred way to open a file.
543
544- Previously, __new__ would only see sequential arguments passed to
545 the type in a constructor call; __init__ would see both sequential
546 and keyword arguments. This made no sense whatsoever any more, so
547 now both __new__ and __init__ see all arguments.
548
549- Previously, hash() applied to an instance of a subclass of str or
550 unicode always returned 0. This has been repaired.
551
552- Previously, an operation on an instance of a subclass of an
553 immutable type (int, long, float, complex, tuple, str, unicode),
554 where the subtype didn't override the operation (and so the
555 operation was handled by the builtin type), could return that
556 instance instead a value of the base type. For example, if s was of
557 a str sublass type, s[:] returned s as-is. Now it returns a str
558 with the same value as s.
559
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000560- Provisional support for pickling new-style objects has been added.
561
Guido van Rossum808eea72001-09-25 04:15:41 +0000562Core
563
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000564- file.writelines() now accepts any iterable object producing strings.
565
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000566- PyUnicode_FromEncodedObject() now works very much like
567 PyObject_Str(obj) in that it tries to use __str__/tp_str
568 on the object if the object is not a string or buffer. This
569 makes unicode() behave like str() when applied to non-string/buffer
570 objects.
571
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000572- PyFile_WriteObject now passes Unicode objects to the file's write
573 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000574 of a print statement must support Unicode objects, i.e. they must
575 at least convert them into ASCII strings.
576
Guido van Rossum624c8af2001-09-18 15:21:04 +0000577- Thread scheduling on Solaris should be improved; it is no longer
578 necessary to insert a small sleep at the start of a thread in order
579 to let other runnable threads be scheduled.
580
Tim Petersb07352e2001-09-08 01:25:47 +0000581Library
582
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000583- StringIO.StringIO instances and cStringIO.StringIO instances support
584 read character buffer compatible objects for their .write() methods.
585 These objects are converted to strings and then handled as such
586 by the instances.
587
Barry Warsaw2f600732001-09-24 04:28:10 +0000588- The "email" package has been added. This is basically a port of the
589 mimelib package <http://sf.net/projects/mimelib> with API changes
590 and some implementations updated to use iterators and generators.
591
Tim Peters8a9c2842001-09-22 21:30:22 +0000592- difflib.ndiff() and difflib.Differ.compare() are generators now. This
593 restores the ability of Tools/scripts/ndiff.py to start producing output
594 before the entire comparison is complete.
595
Barry Warsaw58b072d2001-09-22 04:44:21 +0000596- StringIO.StringIO instances and cStringIO.StringIO instances support
597 iteration just like file objects (i.e. their .readline() method is
598 called for each iteration until it returns an empty string).
599
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000600- The codecs module has grown four new helper APIs to access
601 builtin codecs: getencoder(), getdecoder(), getreader(),
602 getwriter().
603
Guido van Rossum624c8af2001-09-18 15:21:04 +0000604- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
605 simplifies writing XML RPC servers.
606
Barry Warsaw647d5e82001-09-28 17:01:02 +0000607- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000608 after interpretation of symbolic links. On non-Unix systems, this
609 is an alias for os.path.abspath().
610
Tim Peters16a77ad2001-09-08 04:00:12 +0000611- operator.indexOf() (PySequence_Index() in the C API) now works with any
612 iterable object.
613
Guido van Rossum624c8af2001-09-18 15:21:04 +0000614- smtplib now supports various authentication and security features of
615 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000616
Guido van Rossum624c8af2001-09-18 15:21:04 +0000617- hmac: a new module implementing keyed hashing for message
618 authentication.
619
620- mimetypes now recognizes more extensions and file types. At the
621 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000622
Guido van Rossum624c8af2001-09-18 15:21:04 +0000623- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000624 Python 2.2 bytecode generation. It has also been promoted from a
625 Tool to a standard library package. (Tools/compiler still exists as
626 a sample driver.)
627
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000628Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000629
Tim Petersb07352e2001-09-08 01:25:47 +0000630Build
631
Guido van Rossum624c8af2001-09-18 15:21:04 +0000632- Large file support (LFS) is now automatic when the platform supports
633 it; no more manual configuration tweaks are needed. On Linux, at
634 least, it's possible to have a system whose C library supports large
635 files but whose kernel doesn't; in this case, large file support is
636 still enabled but doesn't do you any good unless you upgrade your
637 kernel or share your Python executable with another system whose
638 kernel has large file support.
639
640- The configure script now supplies plausible defaults in a
641 cross-compilation environment. This doesn't mean that the supplied
642 values are always correct, or that cross-compilation now works
643 flawlessly -- but it's a first step (and it shuts up most of
644 autoconf's warnings about AC_TRY_RUN).
645
646- The Unix build is now a bit less chatty, courtesy of the parser
647 generator. The build is completely silent (except for errors) when
648 using "make -s", thanks to a -q option to setup.py.
649
Tim Petersb07352e2001-09-08 01:25:47 +0000650C API
651
Guido van Rossum624c8af2001-09-18 15:21:04 +0000652- The "structmember" API now supports some new flag bits to deny read
653 and/or write access to attributes in restricted execution mode.
654
Tim Petersb07352e2001-09-08 01:25:47 +0000655New platforms
656
Guido van Rossum624c8af2001-09-18 15:21:04 +0000657- Compaq's iPAQ handheld, running the "familiar" Linux distribution
658 (http://familiar.handhelds.org).
659
Tim Petersb07352e2001-09-08 01:25:47 +0000660Tests
661
Tim Peters8a9c2842001-09-22 21:30:22 +0000662- The "classic" standard tests, which work by comparing stdout to
663 an expected-output file under Lib/test/output/, no longer stop at
664 the first mismatch. Instead the test is run to completion, and a
665 variant of ndiff-style comparison is used to report all differences.
666 This is much easier to understand than the previous style of reporting.
667
668- The unittest-based standard tests now use regrtest's test_main()
669 convention, instead of running as a side-effect of merely being
670 imported. This allows these tests to be run in more natural and
671 flexible ways as unittests, outside the regrtest framework.
672
673- regrtest.py is much better integrated with unittest and doctest now,
674 especially in regard to reporting errors.
675
Tim Petersb07352e2001-09-08 01:25:47 +0000676Windows
677
Guido van Rossum624c8af2001-09-18 15:21:04 +0000678- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000679 that support it (NTFS under Windows 2000). See "What's New in
680 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000681
Tim Petersb07352e2001-09-08 01:25:47 +0000682
Tim Petersedc99312001-08-22 21:36:50 +0000683What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000684Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000685===========================
686
687Core
688
Tim Peters9fffa3e2001-09-04 05:14:19 +0000689- Conversion of long to float now raises OverflowError if the long is too
690 big to represent as a C double.
691
Tim Peters32f453e2001-09-03 08:35:41 +0000692- The 3-argument builtin pow() no longer allows a third non-None argument
693 if either of the first two arguments is a float, or if both are of
694 integer types and the second argument is negative (in which latter case
695 the arguments are converted to float, so this is really the same
696 restriction).
697
Tim Peters5d2b77c2001-09-03 05:47:38 +0000698- The builtin dir() now returns more information, and sometimes much
699 more, generally naming all attributes of an object, and all attributes
700 reachable from the object via its class, and from its class's base
701 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
702 an empty list. In 2.2a3,
703
704 >>> dir([])
705 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
706 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
707 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
708 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
709 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
710 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
711 'reverse', 'sort']
712
713 dir(module) continues to return only the module's attributes, though.
714
Tim Petersbdee63f2001-09-02 03:40:59 +0000715- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000716 than raising OverflowError. This is a partial implementation of PEP
717 237. You can use -Wdefault::OverflowWarning to enable a warning for
718 this situation, and -Werror::OverflowWarning to revert to the old
719 OverflowError exception.
720
Guido van Rossum61c345f2001-09-04 03:26:15 +0000721- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000722 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000723 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
724 -Qold, meaning the / operator has its classic meaning and no
725 warnings are issued. Using -Qwarn issues a run-time warning about
726 all uses of classic division for int and long arguments; -Qwarnall
727 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +0000728 (for use with fixdiv.py).
729 [Note: the remainder of this paragraph (preserved below) became
730 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
731 <obsolete>
732 Using -Qnew is questionable; it turns on new division by default, but
733 only in the __main__ module. You can usefully combine -Qwarn or
734 -Qwarnall and -Qnew: this gives the __main__ module new division, and
735 warns about classic division everywhere else.
736 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +0000737
Tim Petersbdee63f2001-09-02 03:40:59 +0000738- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000739 long, float, str, unicode, and tuple. (The types complex, list and
740 dictionary can also be subclassed; this was introduced earlier.)
741 Note that restrictions apply when subclassing immutable built-in
742 types: you can only affect the value of the instance by overloading
743 __new__. You can add mutable attributes, and the subclass instances
744 will have a __dict__ attribute, but you cannot change the "value"
745 (as implemented by the base class) of an immutable subclass instance
746 once it is created.
747
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000748- The dictionary constructor now takes an optional argument, a
749 mapping-like object, and initializes the dictionary from its
750 (key, value) pairs.
751
Tim Petersbdee63f2001-09-02 03:40:59 +0000752- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000753 "cooperative super calls" in a multiple inheritance setting. For an
754 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
755
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000756- A new built-in type, property, has been added. This enables the
757 creation of "properties". These are attributes implemented by
758 getter and setter functions (or only one of these for read-only or
759 write-only attributes), without the need to override __getattr__.
760 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000761
Tim Petersbdee63f2001-09-02 03:40:59 +0000762- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000763 liberalized, to allow leading zeroes. Examples of literals now
764 legal that were SyntaxErrors before:
765
766 00.0 0e3 0100j 07.5 00000000000000000008.
767
Tim Petersbdee63f2001-09-02 03:40:59 +0000768- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000769 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
770
Tim Petersedc99312001-08-22 21:36:50 +0000771Library
772
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000773- telnetlib includes symbolic names for the options, and support for
774 setting an option negotiation callback.
775
Tim Petersa40c7932001-09-05 22:36:56 +0000776- The new C standard no longer requires that math libraries set errno to
777 ERANGE on overflow. For platform libraries that exploit this new
778 freedom, Python's overflow-checking was wholly broken. A new overflow-
779 checking scheme attempts to repair that, but may not be reliable on all
780 platforms (C doesn't seem to provide anything both useful and portable
781 in this area anymore).
782
Martin v. Löwis44f86962001-09-05 13:44:54 +0000783- Asynchronous timeout actions are available through the new class
784 threading.Timer.
785
Tim Peters78526162001-09-05 00:53:45 +0000786- math.log and math.log10 now return sensible results for even huge
787 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
788
Tim Petersbdee63f2001-09-02 03:40:59 +0000789- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000790 currently held. See the docs for the imp module.
791
Tim Petersbdee63f2001-09-02 03:40:59 +0000792- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000793 dumps containing ints written on platforms where Python ints are 8 bytes.
794 When read on a box where Python ints are 4 bytes, such values are
795 converted to Python longs.
796
Tim Petersbdee63f2001-09-02 03:40:59 +0000797- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000798 code objects is no longer allowed. This plugs a security hole.
799
Steve Purcell6091cd62001-09-06 16:05:17 +0000800- unittest.TestResult instances no longer store references to tracebacks
801 generated by test failures. This prevents unexpected dangling references
802 to objects that should be garbage collected between tests.
803
Tim Petersedc99312001-08-22 21:36:50 +0000804Tools
805
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000806- Tools/scripts/fixdiv.py has been added which can be used to fix
807 division operators as per PEP 238.
808
Tim Petersedc99312001-08-22 21:36:50 +0000809Build
810
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000811- If you are an adventurous person using Mac OS X you may want to look at
812 Mac/OSX. There is a Makefile there that will build Python as a real Mac
813 application, which can be used for experimenting with Carbon or Cocoa.
814 Discussion of this on pythonmac-sig, please.
815
Tim Peters7eea37e2001-09-04 22:08:56 +0000816C API
817
818- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000819
Tim Peters9fffa3e2001-09-04 05:14:19 +0000820- Note that PyLong_AsDouble can fail! This has always been true, but no
821 callers checked for it. It's more likely to fail now, because overflow
822 errors are properly detected now. The proper way to check:
823
824 double x = PyLong_AsDouble(some_long_object);
825 if (x == -1.0 && PyErr_Occurred()) {
826 /* The conversion failed. */
827 }
828
Tim Petersbdee63f2001-09-02 03:40:59 +0000829- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000830 compile but will not participate in GC. To upgrade an extension
831 module:
832
833 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000834
Neil Schemenauer4042c692001-08-30 15:38:01 +0000835 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
836 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000837
Neil Schemenauer4042c692001-08-30 15:38:01 +0000838 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
839 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000840
Neil Schemenauer4042c692001-08-30 15:38:01 +0000841 - remove PyGC_HEAD_SIZE from object size calculations
842
843 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
844
Tim Petersbdee63f2001-09-02 03:40:59 +0000845- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000846 These can be used safely to construct string objects from a
847 sprintf-style format string (similar to the format string supported
848 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000849
Tim Petersedc99312001-08-22 21:36:50 +0000850New platforms
851
Tim Petersb7da0902001-09-02 23:01:43 +0000852- Stephen Hansen contributed patches sufficient to get a clean compile
853 under Borland C (Windows), but he reports problems running it and ran
854 out of time to complete the port. Volunteers? Expect a MemoryError
855 when importing the types module; this is probably shallow, and
856 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000857
Tim Petersedc99312001-08-22 21:36:50 +0000858Tests
859
860Windows
861
Tim Peters6e13a562001-09-06 00:32:15 +0000862- Large file support is now enabled on Win32 platforms as well as on
863 Win64. This means that, for example, you can use f.tell() and f.seek()
864 to manipulate files larger than 2 gigabytes (provided you have enough
865 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000866 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
867 filesize limit, and large file support makes no difference there.
868 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
869 NTFS has no practical limit on file size, and files of any size can be
870 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000871
Tim Petersbdee63f2001-09-02 03:40:59 +0000872- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000873 points to command.com (patch from Brian Quinlan).
874
Tim Petersedc99312001-08-22 21:36:50 +0000875
Tim Peters20f51a72001-07-21 02:31:40 +0000876What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000877Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000878===========================
879
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000880Build
881
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000882- Tim Peters developed a brand new Windows installer using Wise 8.1,
883 generously donated to us by Wise Solutions.
884
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000885- configure supports a new option --enable-unicode, with the values
886 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
887 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000888
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000889- A new configure option --enable-framework builds a Mac OS X framework,
890 which "make frameworkinstall" will install. This provides a starting
891 point for more mac-like functionality, join pythonmac-sig@python.org
892 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000893
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000894- The NeXT platform is no longer supported.
895
896- The `new' module is now statically linked.
897
Tim Peters0afb6092001-08-15 06:06:44 +0000898Tools
899
900- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000901 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000902 the module docstring for details.
903
Tim Peters20f51a72001-07-21 02:31:40 +0000904Tests
905
Tim Peters5e824c32001-08-12 22:25:01 +0000906- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000907 platforms, allowing to give clearer test result output. regrtest
908 also has optional --use/-u switch to run normally disabled tests
909 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000910
Tim Peters20f51a72001-07-21 02:31:40 +0000911- Several new tests in the standard test suite, with special thanks to
912 Nick Mathewson.
913
914Core
915
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000916- The floor division operator // has been added as outlined in PEP
917 238. The / operator still provides classic division (and will until
918 Python 3.0) unless "from __future__ import division" is included, in
919 which case the / operator will provide true division. The operator
920 module provides truediv() and floordiv() functions. Augmented
921 assignment variants are included, as are the equivalent overloadable
922 methods and C API methods. See the PEP for a full discussion:
923 <http://python.sf.net/peps/pep-0238.html>
924
Tim Peters6cd6a822001-08-17 22:11:27 +0000925- Future statements are now effective in simulated interactive shells
926 (like IDLE). This should "just work" by magic, but read Michael
927 Hudson's "Future statements in simulated shells" PEP 264 for full
928 details: <http://python.sf.net/peps/pep-0264.html>.
929
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000930- The type/class unification (PEP 252-253) was integrated into the
931 trunk and is not so tentative any more (the exact specification of
932 some features is still tentative). A lot of work has done on fixing
933 bugs and adding robustness and features (performance still has to
934 come a long way).
935
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000936- Warnings about a mismatch in the Python API during extension import
937 now use the Python warning framework (which makes it possible to
938 write filters for these warnings).
939
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000940- A function's __dict__ (aka func_dict) will now always be a
941 dictionary. It used to be possible to delete it or set it to None,
942 but now both actions raise TypeErrors. It is still legal to set it
943 to a dictionary object. Getting func.__dict__ before any attributes
944 have been assigned now returns an empty dictionary instead of None.
945
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000946- A new command line option, -E, was added which disables the use of
947 all environment variables, or at least those that are specifically
948 significant to Python. Usually those have a name starting with
949 "PYTHON". This was used to fix a problem where the tests fail if
950 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
951 older distribution.
952
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000953Library
954
Tim Peters5e824c32001-08-12 22:25:01 +0000955- New class Differ and new functions ndiff() and restore() in difflib.py.
956 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000957 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000958
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000959- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
960 value using the minimal quoting required for the value; more
961 reliable than using xml.sax.saxutils.escape() for attribute values.
962
963- Readline completion support for cmd.Cmd was added.
964
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000965- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
966
967- Added function threading.BoundedSemaphore()
968
969- Added Ka-Ping Yee's cgitb.py module.
970
971- The `new' module now exposes the CO_xxx flags.
972
Martin v. Löwis560da622001-11-24 09:24:51 +0000973- The gc module offers the get_referents function.
974
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000975New platforms
976
977C API
978
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000979- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
980 which provide a cross-platform implementations for the
981 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
982 the standard sprintf() and vsprintf() C lib APIs, these versions
983 apply bounds checking on the used buffer which enhances protection
984 against buffer overruns.
985
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000986- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000987 and extensions using different Unicode widths is rendered next to
988 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000989 will result in an ImportError. Unicode extensions writers must make
990 sure to check the Unicode width compatibility in their extensions by
991 using at least one of the mangled Unicode APIs in the extension.
992
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000993- Two new flags METH_NOARGS and METH_O are available in method definition
994 tables to simplify implementation of methods with no arguments and a
995 single untyped argument. Calling such methods is more efficient than
996 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
997 deprecated.
998
Tim Petersc1731372001-08-04 08:12:36 +0000999Windows
1000
1001- "import module" now compiles module.pyw if it exists and nothing else
1002 relevant is found.
1003
Tim Peters20f51a72001-07-21 02:31:40 +00001004
Guido van Rossum55a78992001-07-17 17:22:32 +00001005What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001006Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001007===========================
1008
1009Core
Tim Petersa814db52001-05-14 07:05:58 +00001010
Tim Peters6d6c1a32001-08-02 04:15:00 +00001011- TENTATIVELY, a large amount of code implementing much of what's
1012 described in PEP 252 (Making Types Look More Like Classes) and PEP
1013 253 (Subtyping Built-in Types) was added. This will be released
1014 with Python 2.2a1. Documentation will be provided separately
1015 through http://www.python.org/2.2/. The purpose of releasing this
1016 with Python 2.2a1 is to test backwards compatibility. It is
1017 possible, though not likely, that a decision is made not to release
1018 this code as part of 2.2 final, if any serious backwards
1019 incompapatibilities are found during alpha testing that cannot be
1020 repaired.
1021
Guido van Rossum55a78992001-07-17 17:22:32 +00001022- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001023 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001024 more 'yield' statements. See PEP 255. Since this adds a new
1025 keyword to the language, this feature must be enabled by including a
1026 future statement: "from __future__ import generators" (see PEP 236).
1027 Generators will become a standard feature in a future release
1028 (probably 2.3). Without this future statement, 'yield' remains an
1029 ordinary identifier, but a warning is issued each time it is used.
1030 (These warnings currently don't conform to the warnings framework of
1031 PEP 230; we intend to fix this in 2.2a2.)
1032
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001033- The UTF-16 codec was modified to be more RFC compliant. It will now
1034 only remove BOM characters at the start of the string and then
1035 only if running in native mode (UTF-16-LE and -BE won't remove a
1036 leading BMO character).
1037
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001038- Strings now have a new method .decode() to complement the already
1039 existing .encode() method. These two methods provide direct access
1040 to the corresponding decoders and encoders of the registered codecs.
1041
1042 To enhance the usability of the .encode() method, the special
1043 casing of Unicode object return values was dropped (Unicode objects
1044 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001045
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001046 Both methods will now return whatever the codec in charge of the
1047 requested encoding returns as object, e.g. Unicode codecs will
1048 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1049 will return u"äöü"). This enables codec writer to create codecs
1050 for various simple to use conversions.
1051
1052 New codecs were added to demonstrate these new features (the .encode()
1053 and .decode() columns indicate the type of the returned objects):
1054
1055 Name | .encode() | .decode() | Description
1056 ----------------------------------------------------------------------
1057 uu | string | string | UU codec (e.g. for email)
1058 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001059 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001060 zlib | string | string | zlib compression
1061 hex | string | string | 2-byte hex codec
1062 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1063
Mark Hammond2a0af792001-05-14 03:09:36 +00001064- Some operating systems now support the concept of a default Unicode
1065 encoding for file system operations. Notably, Windows supports 'mbcs'
1066 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001067 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001068 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001069
1070 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001071 functions that return filenames (such as os.listdir()) to return Python
1072 string objects pre-encoded using the default file system encoding for
1073 the platform. As this encoding is likely to be different from Python's
1074 default encoding, converting this name to a Unicode object before passing
1075 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001076 would attempt to use its default encoding (generally ASCII) rather than
1077 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001078
Tim Petersa814db52001-05-14 07:05:58 +00001079 In general, this change simply removes surprises when working with
1080 Unicode and the file system, making these operations work as you expect,
1081 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001082 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001083
Tim Peters61dff2b2001-05-08 15:43:37 +00001084- Float (and complex) literals in source code were evaluated to full
1085 precision only when running from a .py file; the same code loaded from a
1086 .pyc (or .pyo) file could suffer numeric differences starting at about the
1087 12th significant decimal digit. For example, on a machine with IEEE-754
1088 floating arithmetic,
1089
1090 x = 9007199254740992.0
1091 print long(x)
1092
1093 printed 9007199254740992 if run directly from .py, but 9007199254740000
1094 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1095 str(float) instead of repr(float) when building code objects. marshal
1096 now uses repr(float) instead, which should reproduce floats to full
1097 machine precision (assuming the platform C float<->string I/O conversion
1098 functions are of good quality).
1099
1100 This may cause floating-point results to change in some cases, and
1101 usually for the better, but may also cause numerically unstable
1102 algorithms to break.
1103
Tim Peters2f228e72001-05-13 00:19:31 +00001104- The implementation of dicts suffers fewer collisions, which has speed
1105 benefits. However, the order in which dict entries appear in dict.keys(),
1106 dict.values() and dict.items() may differ from previous releases for a
1107 given dict. Nothing is defined about this order, so no program should
1108 rely on it. Nevertheless, it's easy to write test cases that rely on the
1109 order by accident, typically because of printing the str() or repr() of a
1110 dict to an "expected results" file. See Lib/test/test_support.py's new
1111 sortdict(dict) function for a simple way to display a dict in sorted
1112 order.
1113
Tim Peters7a3bfc32001-06-12 01:22:22 +00001114- Many other small changes to dicts were made, resulting in faster
1115 operation along the most common code paths.
1116
Guido van Rossum10315822001-05-01 20:54:30 +00001117- Dictionary objects now support the "in" operator: "x in dict" means
1118 the same as dict.has_key(x).
1119
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001120- The update() method of dictionaries now accepts generic mapping
1121 objects. Specifically the argument object must support the .keys()
1122 and __getitem__() methods. This allows you to say, for example,
1123 {}.update(UserDict())
1124
Guido van Rossum10315822001-05-01 20:54:30 +00001125- Iterators were added; this is a generalized way of providing values
1126 to a for loop. See PEP 234. There's a new built-in function iter()
1127 to return an iterator. There's a new protocol to get the next value
1128 from an iterator using the next() method (in Python) or the
1129 tp_iternext slot (in C). There's a new protocol to get iterators
1130 using the __iter__() method (in Python) or the tp_iter slot (in C).
1131 Iterating (i.e. a for loop) over a dictionary generates its keys.
1132 Iterating over a file generates its lines.
1133
Tim Petersf553f892001-05-01 20:45:31 +00001134- The following functions were generalized to work nicely with iterator
1135 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001136 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001137 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1138 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001139 join() method of strings
1140 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001141 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1142 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001143 right-hand side of assignment statements with multiple targets, such as
1144 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001145
Tim Petersd85e1022001-05-11 21:51:48 +00001146- Accessing module attributes is significantly faster (for example,
1147 random.random or os.path or yourPythonModule.yourAttribute).
1148
Tim Peterse63415e2001-05-08 04:38:29 +00001149- Comparing dictionary objects via == and != is faster, and now works even
1150 if the keys and values don't support comparisons other than ==.
1151
Tim Peters95bf9392001-05-10 08:32:44 +00001152- Comparing dictionaries in ways other than == and != is slower: there were
1153 insecurities in the dict comparison implementation that could cause Python
1154 to crash if the element comparison routines for the dict keys and/or
1155 values mutated the dicts. Making the code bulletproof slowed it down.
1156
Tim Peterseb28ef22001-06-02 05:27:19 +00001157- Collisions in dicts are resolved via a new approach, which can help
1158 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001159 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001160 faster now. Thanks to Christian Tismer for pointing out the cause and
1161 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001162
Tim Peters52e155e2001-06-16 05:42:57 +00001163- repr() is much faster for large containers (dict, list, tuple).
1164
1165
Tim Petersa814db52001-05-14 07:05:58 +00001166Library
1167
Fred Drake960fdf92001-07-20 18:38:26 +00001168- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1169 were added to the string module. These a locale-indenpendent
1170 constants, unlike letters, lowercase, and uppercase. These are now
1171 use in appropriate locations in the standard library.
1172
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001173- The flags used in dlopen calls can now be configured using
1174 sys.setdlopenflags and queried using sys.getdlopenflags.
1175
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001176- Fredrik Lundh's xmlrpclib is now a standard library module. This
1177 provides full client-side XML-RPC support. In addition,
1178 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1179 one asyncore-based). Thanks to Eric Raymond for the documentation.
1180
Guido van Rossum643d3912001-07-05 14:46:25 +00001181- The xrange() object is simplified: it no longer supports slicing,
1182 repetition, comparisons, efficient 'in' checking, the tolist()
1183 method, or the start, stop and step attributes. See PEP 260.
1184
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001185- A new function fnmatch.filter to filter lists of file names was added.
1186
Barry Warsawffd674d2001-05-22 16:00:10 +00001187- calendar.py uses month and day names based on the current locale.
1188
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001189- strop is now *really* obsolete (this was announced before with 1.6),
1190 and issues DeprecationWarning when used (except for the four items
1191 that are still imported into string.py).
1192
Tim Petersa814db52001-05-14 07:05:58 +00001193- Cookie.py now sorts key+value pairs by key in output strings.
1194
1195- pprint.isrecursive(object) didn't correctly identify recursive objects.
1196 Now it does.
1197
Tim Peters95b3f782001-05-14 18:39:41 +00001198- pprint functions now much faster for large containers (tuple, list, dict).
1199
Tim Peters7b9542a2001-06-10 23:40:19 +00001200- New 'q' and 'Q' format codes in the struct module, corresponding to C
1201 types "long long" and "unsigned long long" (on Windows, __int64). In
1202 native mode, these can be used only when the platform C compiler supports
1203 these types (when HAVE_LONG_LONG is #define'd by the Python config
1204 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001205 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1206 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001207
Guido van Rossum83213cc2001-06-12 16:48:52 +00001208- The site module installs a new built-in function 'help' that invokes
1209 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1210 it displays a message reminding the user to use 'help()' or
1211 'help(object)'.
1212
Tim Petersa814db52001-05-14 07:05:58 +00001213Tests
1214
1215- New test_mutants.py runs dict comparisons where the key and value
1216 comparison operators mutute the dicts randomly during comparison. This
1217 rapidly causes Python to crash under earlier releases (not for the faint
1218 of heart: it can also cause Win9x to freeze or reboot!).
1219
1220- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001221 pprint.isreadable() return sensible results. Also verifies that simple
1222 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001223
Tim Peters4324aa32001-05-28 22:30:08 +00001224C API
1225
1226- Removed the unused last_is_sticky argument from the internal
1227 _PyTuple_Resize(). If this affects you, you were cheating.
1228
1229
Guido van Rossum55a78992001-07-17 17:22:32 +00001230======================================================================
1231
1232
Guido van Rossumffe13be2001-04-16 18:46:45 +00001233What's New in Python 2.1 (final)?
1234=================================
1235
1236We only changed a few things since the last release candidate, all in
1237Python library code:
1238
1239- A bug in the locale module was fixed that affected locales which
1240 define no grouping for numeric formatting.
1241
1242- A few bugs in the weakref module's implementations of weak
1243 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1244 and the test suite was updated to check for these bugs.
1245
1246- An old bug in the os.path.walk() function (introduced in Python
1247 2.0!) was fixed: a non-existent file would cause an exception
1248 instead of being ignored.
1249
1250- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1251 PyChecker.
1252
1253
Guido van Rossum5b08f132001-04-16 02:05:23 +00001254What's New in Python 2.1c2?
1255===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001256
Guido van Rossum5b08f132001-04-16 02:05:23 +00001257A flurry of small changes, and one showstopper fixed in the nick of
1258time made it necessary to release another release candidate. The list
1259here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001260
Guido van Rossum5b08f132001-04-16 02:05:23 +00001261Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001262
Guido van Rossum5b08f132001-04-16 02:05:23 +00001263- Tim discovered a nasty bug in the dictionary code, caused by
1264 PyDict_Next() calling dict_resize(), and the GC code's use of
1265 PyDict_Next() violating an assumption in dict_items(). This was
1266 fixed with considerable amounts of band-aid, but the net effect is a
1267 saner and more robust implementation.
1268
1269- Made a bunch of symbols static that were accidentally global.
1270
1271Build and Ports
1272
1273- The setup.py script didn't check for a new enough version of zlib
1274 (1.1.3 is needed). Now it does.
1275
1276- Changed "make clean" target to also remove shared libraries.
1277
1278- Added a more general warning about the SGI Irix optimizer to README.
1279
1280Library
1281
1282- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1283 omitted the slash between host and file.html.
1284
1285- The mailbox module's _Mailbox class contained a completely broken
1286 and undocumented seek() method. Ripped it out.
1287
1288- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1289 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1290
1291- Fixed a few last-minute bugs in unittest.
1292
1293Extensions
1294
1295- Reverted the patch to the OpenSSL code in socketmodule.c to support
1296 RAND_status() and the EGD, and the subsequent patch that tried to
1297 fix it for pre-0.9.5 versions; the problem with the patch is that on
1298 some systems it issues a warning whenever socket is imported, and
1299 that's unacceptable.
1300
1301Tests
1302
1303- Fixed the pickle tests to work with "import test.test_pickle".
1304
1305- Tweaked test_locale.py to actually run the test Windows.
1306
1307- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1308 not "wb" (which is not a valid mode at all).
1309
1310- Fix pstats browser crashes. Import readline if it exists to make
1311 the user interface nicer.
1312
1313- Add "import thread" to the top of test modules that import the
1314 threading module (test_asynchat and test_threadedtempfile). This
1315 prevents test failures caused by a broken threading module resulting
1316 from a previously caught failed import.
1317
1318- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1319 needed on some platforms (e.g. Solaris 8) when the tests are run
1320 twice in succession.
1321
1322- Skip rather than fail test_sunaudiodev if no audio device is found.
1323
1324
1325What's New in Python 2.1c1?
1326===========================
1327
1328This list was significantly updated when 2.1c2 was released; the 2.1c1
1329release didn't mention most changes that were actually part of 2.1c1:
1330
1331Legal
1332
1333- Copyright was assigned to the Python Software Foundation (PSF) and a
1334 PSF license (very similar to the CNRI license) was added.
1335
1336- The CNRI copyright notice was updated to include 2001.
1337
1338Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001339
Guido van Rossumc9932722001-04-12 02:31:27 +00001340- After a public outcry, assignment to __debug__ is no longer illegal;
1341 instead, a warning is issued. It will become illegal in 2.2.
1342
Guido van Rossum5b08f132001-04-16 02:05:23 +00001343- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1344 "%#x" now always prepends "0x", even if the value is zero.
1345
1346- Fixed some nits in the bytecode compiler.
1347
1348- Fixed core dumps when calling certain kinds of non-functions.
1349
1350- Fixed various core dumps caused by reference count bugs.
1351
1352Build and Ports
1353
1354- Use INSTALL_SCRIPT to install script files.
1355
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001356- New port: SCO Unixware 7, by Billy G. Allie.
1357
Guido van Rossum5b08f132001-04-16 02:05:23 +00001358- Updated RISCOS port.
1359
1360- Updated BeOS port and notes.
1361
1362- Various other porting problems resolved.
1363
1364Library
1365
1366- The TERMIOS and SOCKET modules are now truly obsolete and
1367 unnecessary. Their symbols are incorporated in the termios and
1368 socket modules.
1369
1370- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1371 better tests for pickling.
1372
1373- threading: make Condition.wait() robust against KeyboardInterrupt.
1374
1375- zipfile: add support to zipfile to support opening an archive
1376 represented by an open file rather than a file name. Fix bug where
1377 the archive was not properly closed. Fixed a bug in this bugfix
1378 where flush() was called for a read-only file.
1379
1380- imputil: added an uninstall() method to the ImportManager.
1381
1382- Canvas: fixed bugs in lower() and tkraise() methods.
1383
1384- SocketServer: API change (added overridable close_request() method)
1385 so that the TCP server can explicitly close the request.
1386
1387- pstats: Eric Raymond added a simple interactive statistics browser,
1388 invoked when the module is run as a script.
1389
1390- locale: fixed a problem in format().
1391
1392- webbrowser: made it work when the BROWSER environment variable has a
1393 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1394 KDE 2. Fixed some other nits.
1395
1396- unittest: changes to allow using a different exception than
1397 AssertionError, and added a few more function aliases. Some other
1398 small changes.
1399
1400- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1401
1402- asynchat: fixed a critical bug in asynchat that slipped through the
1403 2.1b2 release. Fixed another rare bug.
1404
1405- Fix some unqualified except: clauses (always a bad code example).
1406
1407XML
1408
1409- pyexpat: new API get_version_string().
1410
1411- Fixed some minidom bugs.
1412
1413Extensions
1414
1415- Fixed a core dump in _weakref. Removed the weakref.mapping()
1416 function (it adds nothing to the API).
1417
1418- Rationalized the use of header files in the readline module, to make
1419 it compile (albeit with some warnings) with the very recent readline
1420 4.2, without breaking for earlier versions.
1421
1422- Hopefully fixed a buffering problem in linuxaudiodev.
1423
1424- Attempted a fix to make the OpenSSL support in the socket module
1425 work again with pre-0.9.5 versions of OpenSSL.
1426
1427Tests
1428
1429- Added a test case for asynchat and asyncore.
1430
1431- Removed coupling between tests where one test failing could break
1432 another.
1433
1434Tools
1435
1436- Ping added an interactive help browser to pydoc, fixed some nits
1437 in the rest of the pydoc code, and added some features to his
1438 inspect module.
1439
1440- An updated python-mode.el version 4.1 which integrates Ken
1441 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1442 much nicer in XEmacs and Emacs. When stepping through your program
1443 with pdb, in either the shell window or the *Python* window, the
1444 source file and line will be tracked by an arrow. Very cool!
1445
1446- IDLE: syntax warnings in interactive mode are changed into errors.
1447
1448- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001449 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001450
1451- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001452
Barry Warsaw11e89c72001-04-11 20:37:57 +00001453
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001454What's New in Python 2.1 beta 2?
1455================================
1456
Guido van Rossum053ae352001-03-22 14:17:21 +00001457(Unlisted are many fixed bugs, more documentation, etc.)
1458
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001459Core language, builtins, and interpreter
1460
Guido van Rossum053ae352001-03-22 14:17:21 +00001461- The nested scopes work (enabled by "from __future__ import
1462 nested_scopes") is completed; in particular, the future now extends
1463 into code executed through exec, eval() and execfile(), and into the
1464 interactive interpreter.
1465
1466- When calling a base class method (e.g. BaseClass.__init__(self)),
1467 this is now allowed even if self is not strictly spoken a class
1468 instance (e.g. when using metaclasses or the Don Beaudry hook).
1469
1470- Slice objects are now comparable but not hashable; this prevents
1471 dict[:] from being accepted but meaningless.
1472
1473- Complex division is now calculated using less braindead algorithms.
1474 This doesn't change semantics except it's more likely to give useful
1475 results in extreme cases. Complex repr() now uses full precision
1476 like float repr().
1477
1478- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1479
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001480- It is illegal to assign to the name __debug__, which is set when the
1481 interpreter starts. It is effectively a compile-time constant.
1482
1483- A warning will be issued if a global statement for a variable
1484 follows a use or assignment of that variable.
1485
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001486Standard library
1487
Guido van Rossum053ae352001-03-22 14:17:21 +00001488- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1489 inspired by JUnit), is now part of the standard library. You now
1490 have a choice of two testing frameworks: unittest requires you to
1491 write testcases as separate code, doctest gathers them from
1492 docstrings. Both approaches have their advantages and
1493 disadvantages.
1494
1495- A new module Tix was added, which wraps the Tix extension library
1496 for Tk. With that module, it is not necessary to statically link
1497 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1498 require" command. See Demo/tix/.
1499
1500- tzparse.py is now obsolete.
1501
1502- In gzip.py, the seek() and tell() methods are removed -- they were
1503 non-functional anyway, and it's better if callers can test for their
1504 existence with hasattr().
1505
1506Python/C API
1507
1508- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1509 that's already in the dictionary during a PyDict_Next() iteration.
1510 This used to fail occasionally when a dictionary resize operation
1511 could be triggered that would rehash all the keys. All other
1512 modifications to the dictionary are still off-limits during a
1513 PyDict_Next() iteration!
1514
1515- New extended APIs related to passing compiler variables around.
1516
1517- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1518 implement isinstance() and issubclass().
1519
1520- Py_BuildValue() now has a "D" conversion to create a Python complex
1521 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001522
Fred Drake4e262a92001-03-22 18:26:47 +00001523- Extensions types which support weak references must now set the
1524 field allocated for the weak reference machinery to NULL themselves;
1525 this is done to avoid the cost of checking each object for having a
1526 weakly referencable type in PyObject_INIT(), since most types are
1527 not weakly referencable.
1528
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001529- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1530 free variables and cell variables to and from the frame's f_locals.
1531
1532- Variants of several functions defined in pythonrun.h have been added
1533 to support the nested_scopes future statement. The variants all end
1534 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1535 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1536 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001537 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001538
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001539Distutils
1540
1541- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1542 into the release tree.
1543
Tim Peters0e57abf2001-05-02 07:39:38 +00001544- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001545 (an uninstaller, more customization of the installer's display)
1546
1547- from Jack Jansen: added Mac-specific code to generate a dialog for
1548 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001549 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001550 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001551
1552- added 'platforms' and 'keywords' to the set of metadata that can be
1553 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001554
1555- applied patches from Jason Tishler to make the compiler class work with
1556 Cygwin.
1557
1558
Tim Peters2fe289a2001-03-01 22:19:38 +00001559What's New in Python 2.1 beta 1?
1560================================
Tim Petersd66595f2001-02-04 03:09:53 +00001561
1562Core language, builtins, and interpreter
1563
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001564- Following an outcry from the community about the amount of code
1565 broken by the nested scopes feature introduced in 2.1a2, we decided
1566 to make this feature optional, and to wait until Python 2.2 (or at
1567 least 6 months) to make it standard. The option can be enabled on a
1568 per-module basis by adding "from __future__ import nested_scopes" at
1569 the beginning of a module (before any other statements, but after
1570 comments and an optional docstring). See PEP 236 (Back to the
1571 __future__) for a description of the __future__ statement. PEP 227
1572 (Statically Nested Scopes) has been updated to reflect this change,
1573 and to clarify the semantics in a number of endcases.
1574
1575- The nested scopes code, when enabled, has been hardened, and most
1576 bugs and memory leaks in it have been fixed.
1577
1578- Compile-time warnings are now generated for a number of conditions
1579 that will break or change in meaning when nested scopes are enabled:
1580
1581 - Using "from...import *" or "exec" without in-clause in a function
1582 scope that also defines a lambda or nested function with one or
1583 more free (non-local) variables. The presence of the import* or
1584 bare exec makes it impossible for the compiler to determine the
1585 exact set of local variables in the outer scope, which makes it
1586 impossible to determine the bindings for free variables in the
1587 inner scope. To avoid the warning about import *, change it into
1588 an import of explicitly name object, or move the import* statement
1589 to the global scope; to avoid the warning about bare exec, use
1590 exec...in... (a good idea anyway -- there's a possibility that
1591 bare exec will be deprecated in the future).
1592
1593 - Use of a global variable in a nested scope with the same name as a
1594 local variable in a surrounding scope. This will change in
1595 meaning with nested scopes: the name in the inner scope will
1596 reference the variable in the outer scope rather than the global
1597 of the same name. To avoid the warning, either rename the outer
1598 variable, or use a global statement in the inner function.
1599
Neil Schemenauera35c6882001-02-27 04:45:05 +00001600- An optional object allocator has been included. This allocator is
1601 optimized for Python objects and should be faster and use less memory
1602 than the standard system allocator. It is not enabled by default
1603 because of possible thread safety problems. The allocator is only
1604 protected by the Python interpreter lock and it is possible that some
1605 extension modules require a thread safe allocator. The object
1606 allocator can be enabled by providing the "--with-pymalloc" option to
1607 configure.
1608
Tim Petersd66595f2001-02-04 03:09:53 +00001609Standard library
1610
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001611- pyexpat now detects the expat version if expat.h defines it. A
1612 number of additional handlers are provided, which are only available
1613 since expat 1.95. In addition, the methods SetParamEntityParsing and
1614 GetInputContext of Parser objects are available with 1.95.x
1615 only. Parser objects now provide the ordered_attributes and
1616 specified_attributes attributes. A new module expat.model was added,
1617 which offers a number of additional constants if 1.95.x is used.
1618
1619- xml.dom offers the new functions registerDOMImplementation and
1620 getDOMImplementation.
1621
1622- xml.dom.minidom offers a toprettyxml method. A number of DOM
1623 conformance issues have been resolved. In particular, Element now
1624 has an hasAttributes method, and the handling of namespaces was
1625 improved.
1626
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001627- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1628 getting information about live Python code, and pydoc.py, a module
1629 for interactively converting docstrings to HTML or text.
1630 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001631 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001632 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1633 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001634
Tim Peters1eff7962001-03-01 02:31:33 +00001635- New library module difflib.py, primarily packaging the SequenceMatcher
1636 class at the heart of the popular ndiff.py file-comparison tool.
1637
1638- doctest.py (a framework for verifying Python code examples in docstrings)
1639 is now part of the std library.
1640
Tim Petersd66595f2001-02-04 03:09:53 +00001641Windows changes
1642
Guido van Rossume3955a82001-03-02 14:05:59 +00001643- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1644 small GUI that lets you browse the module docstrings using your
1645 default web browser.
1646
Tim Peters1eff7962001-03-01 02:31:33 +00001647- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1648 Platforms) is implemented. See
1649
1650 http://python.sourceforge.net/peps/pep-0235.html
1651
1652 for full details, especially the "Current Lower-Left Semantics" section.
1653 The new Windows import rules are simpler than before:
1654
1655 A. If the PYTHONCASEOK environment variable exists, same as
1656 before: silently accept the first case-insensitive match of any
1657 kind; raise ImportError if none found.
1658
1659 B. Else search sys.path for the first case-sensitive match; raise
1660 ImportError if none found.
1661
1662 The same rules have been implented on other platforms with case-
1663 insensitive but case-preserving filesystems too (including Cygwin, and
1664 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001665
Tim Peters25a9ce32001-02-19 07:06:36 +00001666- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1667 what it's supposed to do (and does do under NT and 2000) via direct
1668 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001669 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001670 all Win9x systems before.
1671
Tim Peters1eff7962001-03-01 02:31:33 +00001672- Build: Subproject _test (effectively) renamed to _testcapi.
1673
Tim Peters2fe289a2001-03-01 22:19:38 +00001674New platforms
1675
1676- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1677 Thanks to Steven Majewski!
1678
1679- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1680 Tishler!
1681
Guido van Rossum9089b272001-03-02 06:49:50 +00001682- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1683 Schwertberger! See RISCOS/README for more information -- it seems
1684 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001685 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001686
Tim Peters25a9ce32001-02-19 07:06:36 +00001687
Tim Petersd7b5e882001-01-25 03:36:26 +00001688What's New in Python 2.1 alpha 2?
1689=================================
Tim Peters40ead762001-01-27 05:35:26 +00001690
Tim Petersd7b5e882001-01-25 03:36:26 +00001691Core language, builtins, and interpreter
1692
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001693- Scopes nest. If a name is used in a function or class, but is not
1694 local, the definition in the nearest enclosing function scope will
1695 be used. One consequence of this change is that lambda statements
1696 could reference variables in the namespaces where the lambda is
1697 defined. In some unusual cases, this change will break code.
1698
1699 In all previous version of Python, names were resolved in exactly
1700 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001701 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001702 function A is defined within a function B, the names bound in B are
1703 not visible in A. The new rules make names bound in B visible in A,
1704 unless A contains a name binding that hides the binding in B.
1705
1706 Section 4.1 of the reference manual describes the new scoping rules
1707 in detail. The test script in Lib/test/test_scope.py demonstrates
1708 some of the effects of the change.
1709
1710 The new rules will cause existing code to break if it defines nested
1711 functions where an outer function has local variables with the same
1712 name as globals or builtins used by the inner function. Example:
1713
1714 def munge(str):
1715 def helper(x):
1716 return str(x)
1717 if type(str) != type(''):
1718 str = helper(str)
1719 return str.strip()
1720
1721 Under the old rules, the name str in helper() is bound to the
1722 builtin function str(). Under the new rules, it will be bound to
1723 the argument named str and an error will occur when helper() is
1724 called.
1725
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001726- The compiler will report a SyntaxError if "from ... import *" occurs
1727 in a function or class scope. The language reference has documented
1728 that this case is illegal, but the compiler never checked for it.
1729 The recent introduction of nested scope makes the meaning of this
1730 form of name binding ambiguous. In a future release, the compiler
1731 may allow this form when there is no possibility of ambiguity.
1732
Tim Peters40ead762001-01-27 05:35:26 +00001733- repr(string) is easier to read, now using hex escapes instead of octal,
1734 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1735
1736 >>> "\texample \r\n" + chr(0) + chr(255)
1737 '\texample \r\n\x00\xff' # in 2.1
1738 '\011example \015\012\000\377' # in 2.0
1739
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001740- Functions are now compared and hashed by identity, not by value, since
1741 the func_code attribute is writable.
1742
Fred Drakefb9d7122001-02-01 20:00:40 +00001743- Weak references (PEP 205) have been added. This involves a few
1744 changes in the core, an extension module (_weakref), and a Python
1745 module (weakref). The weakref module is the public interface. It
1746 includes support for "explicit" weak references, proxy objects, and
1747 mappings with weakly held values.
1748
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001749- A 'continue' statement can now appear in a try block within the body
1750 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001751 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001752
Tim Petersd7b5e882001-01-25 03:36:26 +00001753Standard library
1754
Barry Warsaw30dbd142001-01-31 22:14:01 +00001755- mailbox.py now has a new class, PortableUnixMailbox which is
1756 identical to UnixMailbox but uses a more portable scheme for
1757 determining From_ separators. Also, the constructors for all the
1758 classes in this module have a new optional `factory' argument, which
1759 is a callable used when new message classes must be instantiated by
1760 the next() method.
1761
Tim Petersd7b5e882001-01-25 03:36:26 +00001762- random.py is now self-contained, and offers all the functionality of
1763 the now-deprecated whrandom.py. See the docs for details. random.py
1764 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001765 and restoring the internal state of the generator; and jumpahead(n),
1766 for quickly forcing the internal state to be the same as if n calls to
1767 random() had been made. The latter is particularly useful for multi-
1768 threaded programs, creating one instance of the random.Random() class for
1769 each thread, then using .jumpahead() to force each instance to use a
1770 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001771
Tim Peters0de88fc2001-02-01 04:59:18 +00001772- random.py's seed() function is new. For bit-for-bit compatibility with
1773 prior releases, use the whseed function instead. The new seed function
1774 addresses two problems: (1) The old function couldn't produce more than
1775 about 2**24 distinct internal states; the new one about 2**45 (the best
1776 that can be done in the Wichmann-Hill generator). (2) The old function
1777 sometimes produced identical internal states when passed distinct
1778 integers, and there was no simple way to predict when that would happen;
1779 the new one guarantees to produce distinct internal states for all
1780 arguments in [0, 27814431486576L).
1781
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001782- The socket module now supports raw packets on Linux. The socket
1783 family is AF_PACKET.
1784
Tim Peters9ea17ac2001-02-02 05:57:15 +00001785- test_capi.py is a start at running tests of the Python C API. The tests
1786 are implemented by the new Modules/_testmodule.c.
1787
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001788- A new extension module, _symtable, provides provisional access to the
1789 internal symbol table used by the Python compiler. A higher-level
1790 interface will be added on top of _symtable in a future release.
1791
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001792- Removed the obsolete soundex module.
1793
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001794- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1795 the isSameNode method; NamedNodeMap the get method.
1796
1797- xml.sax.expatreader supports the lexical handler property; it
1798 generates comment, startCDATA, and endCDATA events.
1799
Tim Petersee826f82001-01-31 19:39:44 +00001800Windows changes
1801
1802- Build procedure: the zlib project is built in a different way that
1803 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001804 the zlib binary used. See PCbuild\readme.txt for details. Your old
1805 zlib-related directories can be deleted; you'll need to download fresh
1806 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001807
Tim Peters9ea17ac2001-02-02 05:57:15 +00001808- Build: New subproject _test for the benefit of test_capi.py (see above).
1809
Tim Petersb16c56f2001-02-02 21:24:51 +00001810- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1811 interface to some Python compiler internals).
1812
1813- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001814 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001815
Tim Petersa3a3a032000-11-30 05:22:44 +00001816What's New in Python 2.1 alpha 1?
1817=================================
1818
1819Core language, builtins, and interpreter
1820
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001821- There is a new Unicode companion to the PyObject_Str() API
1822 called PyObject_Unicode(). It behaves in the same way as the
1823 former, but assures that the returned value is an Unicode object
1824 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001825
Guido van Rossumf98eda02001-01-17 15:54:45 +00001826- The comparison operators support "rich comparison overloading" (PEP
1827 207). C extension types can provide a rich comparison function in
1828 the new tp_richcompare slot in the type object. The cmp() function
1829 and the C function PyObject_Compare() first try the new rich
1830 comparison operators before trying the old 3-way comparison. There
1831 is also a new C API PyObject_RichCompare() (which also falls back on
1832 the old 3-way comparison, but does not constrain the outcome of the
1833 rich comparison to a Boolean result).
1834
1835 The rich comparison function takes two objects (at least one of
1836 which is guaranteed to have the type that provided the function) and
1837 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1838 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1839 object, which may be NotImplemented (in which case the tp_compare
1840 slot function is used as a fallback, if defined).
1841
1842 Classes can overload individual comparison operators by defining one
1843 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001844 __ge__. There are no explicit "reflected argument" versions of
1845 these; instead, __lt__ and __gt__ are each other's reflection,
1846 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1847 reflection (similar at the C level). No other implications are
1848 made; in particular, Python does not assume that == is the Boolean
1849 inverse of !=, or that < is the Boolean inverse of >=. This makes
1850 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001851
1852 Classes or types that want to implement (in)equality tests but not
1853 the ordering operators (i.e. unordered types) should implement ==
1854 and !=, and raise an error for the ordering operators.
1855
Guido van Rossuma88479f2001-01-18 14:28:08 +00001856 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001857 Boolean; e.g. a matrix type might want to return a matrix of bits
1858 for A < B, giving elementwise comparisons. Such types should ensure
1859 that any interpretation of their value in a Boolean context raises
1860 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1861 at the C level) to always raise an exception.
1862
Guido van Rossuma88479f2001-01-18 14:28:08 +00001863- Complex numbers use rich comparisons to define == and != but raise
1864 an exception for <, <=, > and >=. Unfortunately, this also means
1865 that cmp() of two complex numbers raises an exception when the two
1866 numbers differ. Since it is not mathematically meaningful to compare
1867 complex numbers except for equality, I hope that this doesn't break
1868 too much code.
1869
Tim Peters3389f192001-02-18 08:48:49 +00001870- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001871 not defined by the language, other than that it's arbitrary but
1872 consistent (see the Reference Manual). An implementation detail changed
1873 in 2.1a1 such that None now compares less than any other object. Code
1874 relying on this new behavior (like code that relied on the previous
1875 behavior) does so at its own risk.
1876
Barry Warsaw573b5412001-01-15 20:43:18 +00001877- Functions and methods now support getting and setting arbitrarily
1878 named attributes (PEP 232). Functions have a new __dict__
1879 (a.k.a. func_dict) which hold the function attributes. Methods get
1880 and set attributes on their underlying im_func. It is a TypeError
1881 to set an attribute on a bound method.
1882
Guido van Rossum051e3352001-01-15 19:11:10 +00001883- The xrange() object implementation has been improved so that
1884 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1885 limitation that in this case len(xrange(sys.maxint)) can't be
1886 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1887 work fine as long as the index i doesn't actually reach 2**31.
1888 (Python uses regular ints for sequence and string indices; fixing
1889 that is much more work.)
1890
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001891- Two changes to from...import:
1892
Guido van Rossumba381232001-02-03 15:06:40 +00001893 1) "from M import X" now works even if (after loading module M)
1894 sys.modules['M'] is not a real module; it's basically a getattr()
1895 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001896
1897 2) "from M import *" now looks for M.__all__ to decide which names to
1898 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1899 filters out names starting with '_' as before. Whether or not
1900 __all__ exists, there's no restriction on the type of M.
1901
Guido van Rossumf61f1662001-01-10 20:13:55 +00001902- File objects have a new method, xreadlines(). This is the fastest
1903 way to iterate over all lines in a file:
1904
1905 for line in file.xreadlines():
1906 ...do something to line...
1907
1908 See the xreadlines module (mentioned below) for how to do this for
1909 other file-like objects.
1910
1911- Even if you don't use file.xreadlines(), you may expect a speedup on
1912 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001913 quite a bit in platform-specific ways: on systems (like Linux) that
1914 support flockfile(), getc_unlocked(), and funlockfile(), those are
1915 used by default. On systems (like Windows) without getc_unlocked(),
1916 a complicated (but still thread-safe) method using fgets() is used by
1917 default.
1918
Tim Petersd52269b2001-01-25 06:23:18 +00001919 You can force use of the fgets() method by #define'ing
1920 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001921 getc_unlocked()).
1922
Tim Petersd52269b2001-01-25 06:23:18 +00001923 You can force fgets() not to be used by #define'ing
1924 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001925 test_bufio.py fails -- and let us know if it does!).
1926
1927- In addition, the fileinput module, while still slower than the other
1928 methods on most platforms, has been sped up too, by using
1929 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001930
1931- Support for run-time warnings has been added, including a new
1932 command line option (-W) to specify the disposition of warnings.
1933 See the description of the warnings module below.
1934
1935- Extensive changes have been made to the coercion code. This mostly
1936 affects extension modules (which can now implement mixed-type
1937 numerical operators without having to use coercion), but
1938 occasionally, in boundary cases the coercion semantics have changed
1939 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001940 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001941 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001942 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001943
Guido van Rossumf98eda02001-01-17 15:54:45 +00001944- In connection with the coercion changes, a new built-in singleton
1945 object, NotImplemented is defined. This can be returned for
1946 operations that wish to indicate they are not implemented for a
1947 particular combination of arguments. From C, this is
1948 Py_NotImplemented.
1949
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001950- The interpreter accepts now bytecode files on the command line even
1951 if they do not have a .pyc or .pyo extension. On Linux, after executing
1952
Martin v. Löwise214baa2001-02-04 22:37:56 +00001953import imp,sys,string
1954magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1955reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1956open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001957
1958 any byte code file can be used as an executable (i.e. as an argument
1959 to execve(2)).
1960
Tim Peters9940b802000-12-01 07:59:35 +00001961- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001962 character. In 1.6 and earlier, they never produced a sign,
1963 and raised an error if the value of the long was too large
1964 to fit in a Python int. In 2.0, they produced a sign if and
1965 only if too large to fit in an int. This was inconsistent
1966 across platforms (because the size of an int varies across
1967 platforms), and inconsistent with hex() and oct(). Example:
1968
1969 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001970 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001971 'ffffffbe' # in 2.0 and before, on 32-bit machines
1972 >>> hex(-0x42L)
1973 '-0x42L' # in all versions of Python
1974
Tim Peters9940b802000-12-01 07:59:35 +00001975 The behavior of %d formats for negative Python longs remains
1976 the same as in 2.0 (although in 1.6 and before, they raised
1977 an error if the long didn't fit in a Python int).
1978
1979 %u formats don't make sense for Python longs, but are allowed
1980 and treated the same as %d in 2.1. In 2.0, a negative long
1981 formatted via %u produced a sign if and only if too large to
1982 fit in an int. In 1.6 and earlier, a negative long formatted
1983 via %u raised an error if it was too big to fit in an int.
1984
Guido van Rossum3661d392000-12-12 22:10:31 +00001985- Dictionary objects have an odd new method, popitem(). This removes
1986 an arbitrary item from the dictionary and returns it (in the form of
1987 a (key, value) pair). This can be useful for algorithms that use a
1988 dictionary as a bag of "to do" items and repeatedly need to pick one
1989 item. Such algorithms normally end up running in quadratic time;
1990 using popitem() they can usually be made to run in linear time.
1991
Tim Peters36cdad12000-12-29 02:06:45 +00001992Standard library
1993
Thomas Woutersfe385252001-01-19 23:16:56 +00001994- In the time module, the time argument to the functions strftime,
1995 localtime, gmtime, asctime and ctime is now optional, defaulting to
1996 the current time (in the local timezone).
1997
Guido van Rossumda91f222001-01-15 16:36:08 +00001998- The ftplib module now defaults to passive mode, which is deemed a
1999 more useful default given that clients are often inside firewalls
2000 these days. Note that this could break if ftplib is used to connect
2001 to a *server* that is inside a firewall, from outside; this is
2002 expected to be a very rare situation. To fix that, you can call
2003 ftp.set_pasv(0).
2004
Martin v. Löwis10a27872001-01-13 09:54:41 +00002005- The module site now treats .pth files not only for path configuration,
2006 but also supports extensions to the initialization code: Lines starting
2007 with import are executed.
2008
Guido van Rossumf61f1662001-01-10 20:13:55 +00002009- There's a new module, warnings, which implements a mechanism for
2010 issuing and filtering warnings. There are some new built-in
2011 exceptions that serve as warning categories, and a new command line
2012 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2013 turns warnings into errors). warnings.warn(message[, category])
2014 issues a warning message; this can also be called from C as
2015 PyErr_Warn(category, message).
2016
2017- A new module xreadlines was added. This exports a single factory
2018 function, xreadlines(). The intention is that this code is the
2019 absolutely fastest way to iterate over all lines in an open
2020 file(-like) object:
2021
2022 import xreadlines
2023 for line in xreadlines.xreadlines(file):
2024 ...do something to line...
2025
2026 This is equivalent to the previous the speed record holder using
2027 file.readlines(sizehint). Note that if file is a real file object
2028 (as opposed to a file-like object), this is equivalent:
2029
2030 for line in file.xreadlines():
2031 ...do something to line...
2032
Tim Peters36cdad12000-12-29 02:06:45 +00002033- The bisect module has new functions bisect_left, insort_left,
2034 bisect_right and insort_right. The old names bisect and insort
2035 are now aliases for bisect_right and insort_right. XXX_right
2036 and XXX_left methods differ in what happens when the new element
2037 compares equal to one or more elements already in the list: the
2038 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002039 right. Code that doesn't care where equal elements end up should
2040 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002041
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002042- The new curses.panel module wraps the panel library that forms part
2043 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2044
Guido van Rossumf61f1662001-01-10 20:13:55 +00002045- The SocketServer module now sets the allow_reuse_address flag by
2046 default in the TCPServer class.
2047
2048- A new function, sys._getframe(), returns the stack frame pointer of
2049 the caller. This is intended only as a building block for
2050 higher-level mechanisms such as string interpolation.
2051
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002052- The pyexpat module supports a number of new handlers, which are
2053 available only in expat 1.2. If invocation of a callback fails, it
2054 will report an additional frame in the traceback. Parser objects
2055 participate now in garbage collection. If expat reports an unknown
2056 encoding, pyexpat will try to use a Python codec; that works only
2057 for single-byte charsets. The parser type objects is exposed as
2058 XMLParserObject.
2059
2060- xml.dom now offers standard definitions for symbolic node type and
2061 exception code constants, and a hierarchy of DOM exceptions. minidom
2062 was adjusted to use them.
2063
2064- The conformance of xml.dom.minidom to the DOM specification was
2065 improved. It detects a number of additional error cases; the
2066 previous/next relationship works even when the tree is modified;
2067 Node supports the normalize() method; NamedNodeMap, DocumentType and
2068 DOMImplementation classes were added; Element supports the
2069 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2070 method.
2071
Guido van Rossumf61f1662001-01-10 20:13:55 +00002072Build issues
2073
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002074- For Unix (and Unix-compatible) builds, configuration and building of
2075 extension modules is now greatly automated. Rather than having to
2076 edit the Modules/Setup file to indicate which modules should be
2077 built and where their include files and libraries are, a
2078 distutils-based setup.py script now takes care of building most
2079 extension modules. All extension modules built this way are built
2080 as shared libraries. Only a few modules that must be linked
2081 statically are still listed in the Setup file; you won't need to
2082 edit their configuration.
2083
2084- Python should now build out of the box on Cygwin. If it doesn't,
2085 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002086
2087- Python now always uses its own (renamed) implementation of getopt()
2088 -- there's too much variation among C library getopt()
2089 implementations.
2090
2091- C++ compilers are better supported; the CXX macro is always set to a
2092 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002093
Tim Petersd92dfe02000-12-12 01:18:41 +00002094Windows changes
2095
2096- select module: By default under Windows, a select() call
2097 can specify no more than 64 sockets. Python now boosts
2098 this Microsoft default to 512. If you need even more than
2099 that, see the MS docs (you'll need to #define FD_SETSIZE
2100 and recompile Python from source).
2101
Guido van Rossumf61f1662001-01-10 20:13:55 +00002102- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2103 subdirectory is no more!
2104
Tim Petersa3a3a032000-11-30 05:22:44 +00002105
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002106What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002107=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002108
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002109Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002110changes are in the file HISTORY. If you are making the jump directly
2111from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2112HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002113
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002114Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2115the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2116http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002117
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002118--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002119
2120======================================================================
2121
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002122What's new in 2.0 (since release candidate 1)?
2123==============================================
2124
2125Standard library
2126
2127- The copy_reg module was modified to clarify its intended use: to
2128 register pickle support for extension types, not for classes.
2129 pickle() will raise a TypeError if it is passed a class.
2130
2131- Fixed a bug in gettext's "normalize and expand" code that prevented
2132 it from finding an existing .mo file.
2133
2134- Restored support for HTTP/0.9 servers in httplib.
2135
Tim Peters989b7b92000-10-16 20:24:53 +00002136- The math module was changed to stop raising OverflowError in case of
2137 underflow, and return 0 instead in underflow cases. Whether Python
2138 used to raise OverflowError in case of underflow was platform-
2139 dependent (it did when the platform math library set errno to ERANGE
2140 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002141
2142- Fixed a bug in StringIO that occurred when the file position was not
2143 at the end of the file and write() was called with enough data to
2144 extend past the end of the file.
2145
2146- Fixed a bug that caused Tkinter error messages to get lost on
2147 Windows. The bug was fixed by replacing direct use of
2148 interp->result with Tcl_GetStringResult(interp).
2149
2150- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2151 redirect response.
2152
2153- Several changes were made to distutils: Some debugging code was
2154 removed from util. Fixed the installer used when an external zip
2155 program (like WinZip) is not found; the source code for this
2156 installer is in Misc/distutils. check_lib() was modified to behave
2157 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2158 test for whether installed modules are on sys.path was changed to
2159 use both normcase() and normpath().
2160
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002161- Several minor bugs were fixed in the xml package (the minidom,
2162 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002163
2164- The regression test driver (regrtest.py) behavior when invoked with
2165 -l changed: It now reports a count of objects that are recognized as
2166 garbage but not freed by the garbage collector.
2167
Tim Peters989b7b92000-10-16 20:24:53 +00002168- The regression test for the math module was changed to test
2169 exceptional behavior when the test is run in verbose mode. Python
2170 cannot yet guarantee consistent exception behavior across platforms,
2171 so the exception part of test_math is run only in verbose mode, and
2172 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002173
2174Internals
2175
2176- PyOS_CheckStack() has been disabled on Win64, where it caused
2177 test_sre to fail.
2178
2179Build issues
2180
2181- Changed compiler flags, so that gcc is always invoked with -Wall and
2182 -Wstrict-prototypes. Users compiling Python with GCC should see
2183 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002184 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002185 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002186
Tim Petersa3a3a032000-11-30 05:22:44 +00002187- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002188
2189Tools and other miscellany
2190
2191- The compiler in Tools/compiler was updated to support the new
2192 language features introduced in 2.0: extended print statement, list
2193 comprehensions, and augmented assignments. The new compiler should
2194 also be backwards compatible with Python 1.5.2; the compiler will
2195 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002196 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002197
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002198What's new in 2.0 release candidate 1 (since beta 2)?
2199=====================================================
2200
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002201What is release candidate 1?
2202
2203We believe that release candidate 1 will fix all known bugs that we
2204intend to fix for the 2.0 final release. This release should be a bit
2205more stable than the previous betas. We would like to see even more
2206widespread testing before the final release, so we are producing this
2207release candidate. The final release will be exactly the same unless
2208any show-stopping (or brown bag) bugs are found by testers of the
2209release candidate.
2210
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002211All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002212to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002213
2214Core language, builtins, and interpreter
2215
2216- A bug that caused crashes when __coerce__ was used with augmented
2217 assignment, e.g. +=, was fixed.
2218
2219- Raise ZeroDivisionError when raising zero to a negative number,
2220 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2221 power operator and the result of math.pow(0.0, -2.0) will vary by
2222 platform. On Linux, it raises a ValueError.
2223
2224- A bug in Unicode string interpolation was fixed that occasionally
2225 caused errors with formats including "%%". For example, the
2226 following expression "%% %s" % u"abc" no longer raises a TypeError.
2227
2228- Compilation of deeply nested expressions raises MemoryError instead
2229 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2230
2231- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2232 rendering them useless. They are now written in binary mode again.
2233
2234Standard library
2235
2236- Keyword arguments are now accepted for most pattern and match object
2237 methods in SRE, the standard regular expression engine.
2238
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002239- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002240 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002241
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002242- Several bugs in the Unicode handling and error handling in _tkinter
2243 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002244
2245- Fix memory management errors in Merge() and Tkapp_Call() routines.
2246
2247- Several changes were made to cStringIO to make it compatible with
2248 the file-like object interface and with StringIO. If operations are
2249 performed on a closed object, an exception is raised. The truncate
2250 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002251 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002252
2253- There were many changes made to the linuxaudiodev module and its
2254 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002255 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002256
2257 Note that this module is named poorly, because it should work
2258 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002259 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002260
2261 The module now raises exceptions when errors occur instead of
2262 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2263 audio) and defines a getptr() method that calls the
2264 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2265
2266- The library_version attribute, introduced in an earlier beta, was
2267 removed because it can not be supported with early versions of the C
2268 readline library, which provides no way to determine the version at
2269 compile-time.
2270
2271- The binascii module is now enabled on Win64.
2272
Tim Peters46446d62000-10-09 21:19:31 +00002273- tokenize.py no longer suffers "recursion depth" errors when parsing
2274 programs with very long string literals.
2275
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002276Internals
2277
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002278- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002279 which is called when the interpreter starts up to determine where
2280 the standard library is installed. These vulnerabilities affect all
2281 previous versions of Python and can be exploited by setting very
2282 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2283 setuid Python script, although use of the wrapper in
2284 Misc/setuid-prog.c will eliminate the vulnerability.
2285
2286- Fixed garbage collection bugs in instance creation that were
2287 triggered when errors occurred during initialization. The solution,
2288 applied in cPickle and in PyInstance_New(), is to call
2289 PyObject_GC_Init() after the initialization of the object's
2290 container attributes is complete.
2291
2292- pyexpat adds definitions of PyModule_AddStringConstant and
2293 PyModule_AddObject if the Python version is less than 2.0, which
2294 provides compatibility with PyXML on Python 1.5.2.
2295
2296- If the platform has a bogus definition for LONG_BIT (the number of
2297 bits in a long), an error will be reported at compile time.
2298
2299- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2300 collection crashes and possibly other, unreported crashes.
2301
2302- Fixed a memory leak in _PyUnicode_Fini().
2303
2304Build issues
2305
2306- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002307 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002308 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002309
2310- The mmap.PAGESIZE constant is now initialized using sysconf when
2311 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2312
2313- The md5 file should now compile on all platforms.
2314
2315- The select module now compiles on platforms that do not define
2316 POLLRDNORM and related constants.
2317
2318- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002319 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002320
Jeremy Hylton10921202000-10-09 18:34:12 +00002321- BeOS: A number of changes were made to the build and installation
2322 process. ar-fake now operates on a directory of object files.
2323 dl_export.h is gone, and its macros now appear on the mwcc command
2324 line during build on PPC BeOS.
2325
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002326- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002327 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002328
2329- Cygwin: Support for shared libraries, Tkinter, and sockets.
2330
2331- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2332
2333Tools and other miscellany
2334
2335- Removed debugging prints from main used with freeze.
2336
Tim Peters46446d62000-10-09 21:19:31 +00002337- IDLE auto-indent no longer crashes when it encounters Unicode
2338 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002339
2340What's new in 2.0 beta 2 (since beta 1)?
2341========================================
2342
2343Core language, builtins, and interpreter
2344
Tim Peters482c0212000-09-26 06:33:09 +00002345- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002346 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002347
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002348- Add -h and -V command line options to print the usage message and
2349 Python version number and exit immediately.
2350
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002351- eval() and exec accept Unicode objects as code parameters.
2352
2353- getattr() and setattr() now also accept Unicode objects for the
2354 attribute name, which are converted to strings using the default
2355 encoding before lookup.
2356
2357- Multiplication on string and Unicode now does proper bounds
2358 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2359 string is too long."
2360
2361- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002362 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002363
Jeremy Hylton1b618592000-09-26 05:32:36 +00002364
2365Standard library and extensions
2366
Guido van Rossum5b08f132001-04-16 02:05:23 +00002367- socket module: the OpenSSL code now adds support for RAND_status()
2368 and EGD (Entropy Gathering Device).
2369
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002370- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002371 argument checking; it still takes no arguments.
2372
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002373- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002374
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002375- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002376
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002377- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002378
2379- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002380 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002381
2382- copy: Copy Unicode objects atomically.
2383
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002384- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002385
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002386- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002387
Fred Drake67233bc2000-09-26 16:40:27 +00002388- dbm: Add get() and setdefault() methods to dbm object. Add constant
2389 `library' to module that names the library used. Added doc strings
2390 and method names to error messages. Uses configure to determine
2391 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2392 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002393
2394- distutils: Update to version 0.9.3.
2395
2396- dl: Add several dl.RTLD_ constants.
2397
2398- fpectl: Now supported on FreeBSD.
2399
2400- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2401 found by the collector will be saved in gc.garbage. This is useful
2402 for debugging a program that creates reference cycles.
2403
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002404- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002405 of HTTP class. Do not close socket on zero-length response. Do not
2406 crash when server sends invalid content-length header.
2407
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002408- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002409
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002410- marshal: When reading a short, sign-extend on platforms where shorts
2411 are bigger than 16 bits. When reading a long, repair the unportable
2412 sign extension that was being done for 64-bit machines. (It assumed
2413 that signed right shift sign-extends.)
2414
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002415- operator: Add contains(), invert(), __invert__() as aliases for
2416 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002417
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002418- os: Add support for popen2() and popen3() on all platforms where
2419 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002420
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002421- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002422 clicking on a file in Explorer (or passing the file name to the
2423 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002424
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002425- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002426 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002427
2428- pickle: Now raises ValueError when an invalid pickle that contains
2429 a non-string repr where a string repr was expected. This behavior
2430 matches cPickle.
2431
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002432- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002433
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002434- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002435
2436- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002437 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002438 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002439
2440- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002441 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002442
2443- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002444 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002445 few cycles during startup since the first call to
2446 setdefaultencoding() will initialize the codec registry and the
2447 encodings package.
2448
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002449- socket: Support for size hint in readlines() method of object returned
2450 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002451
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002452- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002453 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002454 is followed by whitespace.
2455
Tim Petersa3a3a032000-11-30 05:22:44 +00002456- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002457
2458- struct: Check ranges for bytes and shorts.
2459
2460- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002461 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002462
2463- Tkinter: Image objects are now guaranteed to have unique ids. Set
2464 event.delta to zero if Tk version doesn't support mousewheel.
2465 Removed some debugging prints.
2466
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002467- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002468
Fred Drake67233bc2000-09-26 16:40:27 +00002469- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002470 which works around a bug in Norton AntiVirus 2000 that leads directly
2471 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002472
2473- xml: New version detection code allows PyXML to override standard
2474 XML package if PyXML version is greater than 0.6.1.
2475
Fred Drake64bb3802000-09-26 16:21:35 +00002476- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2477 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2478 tree only for nodes which are sufficiently interesting to a specific
2479 application. Does not provide the HTML-specific extensions. Still
2480 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002481
Fred Drake64bb3802000-09-26 16:21:35 +00002482- xml.sax: SAX 2 support for Python, including all the handler
2483 interfaces needed to process XML 1.0 compliant XML. Some
2484 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002485
Fred Drake64bb3802000-09-26 16:21:35 +00002486- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2487 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002488
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002489
Jeremy Hylton1b618592000-09-26 05:32:36 +00002490C API
2491
2492- Add three new convenience functions for module initialization --
2493 PyModule_AddObject(), PyModule_AddIntConstant(), and
2494 PyModule_AddStringConstant().
2495
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002496- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002497 removed and add #error to Python.h if NULL isn't defined after
2498 #include of stdio.h.
2499
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002500- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002501 backwards compatibility (at the source level) with old extensions.
2502
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002503- A wrapper API was added for signal() and sigaction(). Instead of
2504 either function, always use PyOS_getsig() to get a signal handler
2505 and PyOS_setsig() to set one. A new convenience typedef
2506 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002507
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002508- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002509 internal data buffer and size of a string object -- or the default
2510 encoded version of a Unicode object.
2511
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002512- PyString_Size() and PyString_AsString() accept Unicode objects.
2513
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002514- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002515 exists). INT_MAX and LONG_MAX will always be defined, even if
2516 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002517
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002518- PyFloat_FromString takes a second argument, pend, that was
2519 effectively useless. It is now officially useless but preserved for
2520 backwards compatibility. If the pend argument is not NULL, *pend is
2521 set to NULL.
2522
2523- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2524 for the attribute name. See note on getattr() above.
2525
2526- A few bug fixes to argument processing for Unicode.
2527 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2528 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2529 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002530 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002531
2532- Py_BuildValue accepts B format (for bgen-generated code).
2533
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002534
Jeremy Hylton1b618592000-09-26 05:32:36 +00002535Internals
2536
2537- On Unix, fix code for finding Python installation directory so that
2538 it works when argv[0] is a relative path.
2539
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002540- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002541 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002542 rather than by generating a copy of the object.
2543
Tim Peters482c0212000-09-26 06:33:09 +00002544- Several of the internal Unicode tables are much smaller now, and
2545 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002546
Jeremy Hylton97693b02000-09-26 17:42:51 +00002547- In the garbage collector: Fixed bug in collection of tuples. Fixed
2548 bug that caused some instances to be removed from the container set
2549 while they were still live. Fixed parsing in gc.set_debug() for
2550 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002551
2552- Fixed refcount problem in instance deallocation that only occurred
2553 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2554
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002555- On Windows, getpythonregpath is now protected against null data in
2556 registry key.
2557
2558- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002559 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002560
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002561
Jeremy Hylton1b618592000-09-26 05:32:36 +00002562Build and platform-specific issues
2563
2564- Better support of GNU Pth via --with-pth configure option.
2565
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002566- Python/C API now properly exposed to dynamically-loaded extension
2567 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002568
2569- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2570 Don't define MS_SYNC to be zero when it is undefined. Added missing
2571 prototypes in posixmodule.c.
2572
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002573- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002574 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002575
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002576- Fix largefile support on older NetBSD systems and OpenBSD by adding
2577 define for TELL64.
2578
2579
2580Tools and other miscellany
2581
2582- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2583
2584- freeze: The modulefinder now works with 2.0 opcodes.
2585
Tim Petersa3a3a032000-11-30 05:22:44 +00002586- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002587 Move hackery of sys.argv until after the Tk instance has been
2588 created, which allows the application-specific Tkinter
2589 initialization to be executed if present; also pass an explicit
2590 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002591
Jeremy Hylton1b618592000-09-26 05:32:36 +00002592
2593What's new in 2.0 beta 1?
2594=========================
2595
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002596Source Incompatibilities
2597------------------------
2598
2599None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2600such as single-argument append(), connect() and bind(), and changes to
2601str(long) and repr(float).
2602
2603
2604Binary Incompatibilities
2605------------------------
2606
2607- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2608with Python 2.0; these extensions will have to be rebuilt for Python
26092.0.
2610
2611- On Windows, attempting to import a third party extension built for
2612Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2613can do about this. Check your PYTHONPATH environment variable!
2614
2615- Python bytecode files (*.pyc and *.pyo) are not compatible between
2616releases.
2617
2618
2619Overview of Changes Since 1.6
2620-----------------------------
2621
2622There are many new modules (including brand new XML support through
2623the xml package, and i18n support through the gettext module); a list
2624of all new modules is included below. Lots of bugs have been fixed.
2625
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002626The process for making major new changes to the language has changed
2627since Python 1.6. Enhancements must now be documented by a Python
2628Enhancement Proposal (PEP) before they can be accepted.
2629
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002630There are several important syntax enhancements, described in more
2631detail below:
2632
2633 - Augmented assignment, e.g. x += 1
2634
2635 - List comprehensions, e.g. [x**2 for x in range(10)]
2636
2637 - Extended import statement, e.g. import Module as Name
2638
2639 - Extended print statement, e.g. print >> file, "Hello"
2640
2641Other important changes:
2642
2643 - Optional collection of cyclical garbage
2644
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002645Python Enhancement Proposal (PEP)
2646---------------------------------
2647
2648PEP stands for Python Enhancement Proposal. A PEP is a design
2649document providing information to the Python community, or describing
2650a new feature for Python. The PEP should provide a concise technical
2651specification of the feature and a rationale for the feature.
2652
2653We intend PEPs to be the primary mechanisms for proposing new
2654features, for collecting community input on an issue, and for
2655documenting the design decisions that have gone into Python. The PEP
2656author is responsible for building consensus within the community and
2657documenting dissenting opinions.
2658
2659The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002660
2661Augmented Assignment
2662--------------------
2663
2664This must have been the most-requested feature of the past years!
2665Eleven new assignment operators were added:
2666
Guido van Rossume905e952000-09-05 12:42:46 +00002667 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002668
2669For example,
2670
2671 A += B
2672
2673is similar to
2674
2675 A = A + B
2676
2677except that A is evaluated only once (relevant when A is something
2678like dict[index].attr).
2679
2680However, if A is a mutable object, A may be modified in place. Thus,
2681if A is a number or a string, A += B has the same effect as A = A+B
2682(except A is only evaluated once); but if a is a list, A += B has the
2683same effect as A.extend(B)!
2684
2685Classes and built-in object types can override the new operators in
2686order to implement the in-place behavior; the not-in-place behavior is
2687used automatically as a fallback when an object doesn't implement the
2688in-place behavior. For classes, the method name is derived from the
2689method name for the corresponding not-in-place operator by inserting
2690an 'i' in front of the name, e.g. __iadd__ implements in-place
2691__add__.
2692
2693Augmented assignment was implemented by Thomas Wouters.
2694
2695
2696List Comprehensions
2697-------------------
2698
2699This is a flexible new notation for lists whose elements are computed
2700from another list (or lists). The simplest form is:
2701
2702 [<expression> for <variable> in <sequence>]
2703
Guido van Rossum56db0952000-09-06 23:34:25 +00002704For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002705This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002706
2707You can also add a condition:
2708
2709 [<expression> for <variable> in <sequence> if <condition>]
2710
2711For example, [w for w in words if w == w.lower()] would yield the list
2712of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002713than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002714
2715You can also have nested for loops and more than one 'if' clause. For
2716example, here's a function that flattens a sequence of sequences::
2717
2718 def flatten(seq):
2719 return [x for subseq in seq for x in subseq]
2720
2721 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2722
2723This prints
2724
2725 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2726
2727List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002728Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002729
2730
2731Extended Import Statement
2732-------------------------
2733
2734Many people have asked for a way to import a module under a different
2735name. This can be accomplished like this:
2736
2737 import foo
2738 bar = foo
2739 del foo
2740
2741but this common idiom gets old quickly. A simple extension of the
2742import statement now allows this to be written as follows:
2743
2744 import foo as bar
2745
2746There's also a variant for 'from ... import':
2747
2748 from foo import bar as spam
2749
2750This also works with packages; e.g. you can write this:
2751
2752 import test.regrtest as regrtest
2753
2754Note that 'as' is not a new keyword -- it is recognized only in this
2755context (this is only possible because the syntax for the import
2756statement doesn't involve expressions).
2757
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002758Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002759
2760
2761Extended Print Statement
2762------------------------
2763
2764Easily the most controversial new feature, this extension to the print
2765statement adds an option to make the output go to a different file
2766than the default sys.stdout.
2767
2768For example, to write an error message to sys.stderr, you can now
2769write:
2770
2771 print >> sys.stderr, "Error: bad dog!"
2772
2773As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002774evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002775
2776 print >> None, "Hello world"
2777
2778is equivalent to
2779
2780 print "Hello world"
2781
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002782Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002783
2784
2785Optional Collection of Cyclical Garbage
2786---------------------------------------
2787
2788Python is now equipped with a garbage collector that can hunt down
2789cyclical references between Python objects. It's no replacement for
2790reference counting; in fact, it depends on the reference counts being
2791correct, and decides that a set of objects belong to a cycle if all
2792their reference counts can be accounted for from their references to
2793each other. This devious scheme was first proposed by Eric Tiedemann,
2794and brought to implementation by Neil Schemenauer.
2795
2796There's a module "gc" that lets you control some parameters of the
2797garbage collection. There's also an option to the configure script
2798that lets you enable or disable the garbage collection. In 2.0b1,
2799it's on by default, so that we (hopefully) can collect decent user
2800experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002801performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002802off by default in the final 2.0 release.
2803
2804
2805Smaller Changes
2806---------------
2807
2808A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2809map(None, seq1, seq2, ...) when the sequences have the same length;
2810i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2811the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002812zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002813
2814sys.version_info is a tuple (major, minor, micro, level, serial).
2815
2816Dictionaries have an odd new method, setdefault(key, default).
2817dict.setdefault(key, default) returns dict[key] if it exists; if not,
2818it sets dict[key] to default and returns that value. Thus:
2819
2820 dict.setdefault(key, []).append(item)
2821
2822does the same work as this common idiom:
2823
2824 if not dict.has_key(key):
2825 dict[key] = []
2826 dict[key].append(item)
2827
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002828There are two new variants of SyntaxError that are raised for
2829indentation-related errors: IndentationError and TabError.
2830
2831Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2832escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002833
2834The limits on the size of expressions and file in Python source code
2835have been raised from 2**16 to 2**32. Previous versions of Python
2836were limited because the maximum argument size the Python VM accepted
2837was 2**16. This limited the size of object constructor expressions,
2838e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2839limit was raised thanks to a patch by Charles Waldman that effectively
2840fixes the problem. It is now much more likely that you will be
2841limited by available memory than by an arbitrary limit in Python.
2842
2843The interpreter's maximum recursion depth can be modified by Python
2844programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2845limit is the maximum number of recursive calls that can be made by
2846Python code. The limit exists to prevent infinite recursion from
2847overflowing the C stack and causing a core dump. The default value is
28481000. The maximum safe value for a particular platform can be found
2849by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002850
2851New Modules and Packages
2852------------------------
2853
2854atexit - for registering functions to be called when Python exits.
2855
2856imputil - Greg Stein's alternative API for writing custom import
2857hooks.
2858
2859pyexpat - an interface to the Expat XML parser, contributed by Paul
2860Prescod.
2861
2862xml - a new package with XML support code organized (so far) in three
2863subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2864would fill a volume. There's a special feature whereby a
2865user-installed package named _xmlplus overrides the standard
2866xmlpackage; this is intended to give the XML SIG a hook to distribute
2867backwards-compatible updates to the standard xml package.
2868
2869webbrowser - a platform-independent API to launch a web browser.
2870
2871
Guido van Rossume905e952000-09-05 12:42:46 +00002872Changed Modules
2873---------------
2874
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002875array -- new methods for array objects: count, extend, index, pop, and
2876remove
2877
2878binascii -- new functions b2a_hex and a2b_hex that convert between
2879binary data and its hex representation
2880
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002881calendar -- Many new functions that support features including control
2882over which day of the week is the first day, returning strings instead
2883of printing them. Also new symbolic constants for days of week,
2884e.g. MONDAY, ..., SUNDAY.
2885
2886cgi -- FieldStorage objects have a getvalue method that works like a
2887dictionary's get method and returns the value attribute of the object.
2888
2889ConfigParser -- The parser object has new methods has_option,
2890remove_section, remove_option, set, and write. They allow the module
2891to be used for writing config files as well as reading them.
2892
2893ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002894optionally support the RFC 959 REST command.
2895
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002896gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002897
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002898httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2899the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002900
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002901locale -- implement getdefaultlocale for Win32 and Macintosh
2902
2903marshal -- no longer dumps core when marshaling deeply nested or
2904recursive data structures
2905
2906os -- new functions isatty, seteuid, setegid, setreuid, setregid
2907
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002908os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2909support under Unix.
2910
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002911os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002912
2913os.path -- fix semantics of os.path.commonprefix
2914
2915smtplib -- support for sending very long messages
2916
2917socket -- new function getfqdn()
2918
2919readline -- new functions to read, write and truncate history files.
2920The readline section of the library reference manual contains an
2921example.
2922
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002923select -- add interface to poll system call
2924
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002925shutil -- new copyfileobj function
2926
2927SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2928HTTP server.
2929
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002930Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002931
2932urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002933e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002934
2935whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002936
2937
2938Obsolete Modules
2939----------------
2940
2941None. However note that 1.6 made a whole slew of modules obsolete:
2942stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2943poly, zmod, strop, util, whatsound.
2944
2945
2946Changed, New, Obsolete Tools
2947----------------------------
2948
Tim Peters8b092332000-09-05 20:15:25 +00002949None.
Guido van Rossume905e952000-09-05 12:42:46 +00002950
2951
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002952C-level Changes
2953---------------
2954
2955Several cleanup jobs were carried out throughout the source code.
2956
2957All C code was converted to ANSI C; we got rid of all uses of the
2958Py_PROTO() macro, which makes the header files a lot more readable.
2959
2960Most of the portability hacks were moved to a new header file,
2961pyport.h; several other new header files were added and some old
2962header files were removed, in an attempt to create a more rational set
2963of header files. (Few of these ever need to be included explicitly;
2964they are all included by Python.h.)
2965
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002966Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002967and Win64, especially for the new Intel Itanium processor. Mick also
2968added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002969
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002970The C APIs to return an object's size have been update to consistently
2971use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2972previous versions, the abstract interfaces used PyXXX_Length and the
2973concrete interfaces used PyXXX_Size. The old names,
2974e.g. PyObject_Length, are still available for backwards compatibility
2975at the API level, but are deprecated.
2976
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002977The PyOS_CheckStack function has been implemented on Windows by
2978Fredrik Lundh. It prevents Python from failing with a stack overflow
2979on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002980
2981The GC changes resulted in creation of two new slots on object,
2982tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002983the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002984
2985The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002986C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002987
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002988PyErr_Format has been updated to automatically calculate the size of
2989the buffer needed to hold the formatted result string. This change
2990prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002991
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002992New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002993
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002994PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2995that are the same as their non-Ex counterparts except they take an
2996extra flag argument that tells them to close the file when done.
2997
2998XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002999
Tim Peters8b092332000-09-05 20:15:25 +00003000
3001Windows Changes
3002---------------
3003
3004New popen2/popen3/peopen4 in os module (see Changed Modules above).
3005
3006os.popen is much more usable on Windows 95 and 98. See Microsoft
3007Knowledge Base article Q150956. The Win9x workaround described there
3008is implemented by the new w9xpopen.exe helper in the root of your
3009Python installation. Note that Python uses this internally; it is not
3010a standalone program.
3011
3012Administrator privileges are no longer required to install Python
3013on Windows NT or Windows 2000. If you have administrator privileges,
3014Python's registry info will be written under HKEY_LOCAL_MACHINE.
3015Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003016under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003017uses of Python, but will prevent some advanced uses from working
3018(for example, running a Python script as an NT service, or possibly
3019from CGI).
3020
3021[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3022installer; instead, it installs the needed Tcl/Tk files directly in the
3023Python directory. If you already have a Tcl/Tk installation, this
3024wastes some disk space (about 4 Megs) but avoids problems with
3025conflicting Tcl/Tk installations, and makes it much easier for Python
3026to ensure that Tcl/Tk can find all its files.
3027
3028[This was new in 1.6] The Windows installer now installs by default in
3029\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3030
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003031
3032Updates to the changes between 1.5.2 and 1.6
3033--------------------------------------------
3034
3035The 1.6 NEWS file can't be changed after the release is done, so here
3036is some late-breaking news:
3037
3038New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3039and changes to getlocale() and setlocale().
3040
3041The new module is now enabled per default.
3042
3043It is not true that the encodings codecs cannot be used for normal
3044strings: the string.encode() (which is also present on 8-bit strings
3045!) allows using them for 8-bit strings too, e.g. to convert files from
3046cp1252 (Windows) to latin-1 or vice-versa.
3047
3048Japanese codecs are available from Tamito KAJIYAMA:
3049http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3050
3051
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003052======================================================================