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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
Tim Peters25059d32001-12-07 20:35:43 +000055- Functions in the os.spawn() family now release the global interpreter
56 lock around calling the platform spawn. They should always have done
57 this, but did not before 2.2c1. Multithreaded programs calling
58 an os.spawn function with P_WAIT will no longer block all Python threads
59 until the spawned program completes. It's possible that some programs
60 relies on blocking, although more likely by accident than by design.
61
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +000062- webbrowser defaults to netscape.exe on OS/2 now.
63
Martin v. Löwis652e1912001-11-25 14:50:56 +000064- Tix.ResizeHandle exposes detach_widget, hide, and show.
65
Martin v. Löwis714d2e22001-12-02 12:26:03 +000066- The charset alias windows_1252 has been added.
67
Tim Petersb3c9af12001-11-17 00:21:57 +000068Tools/Demos
69
70Build
71
Jack Jansen1999ef42001-12-06 21:47:20 +000072- It is no longer necessary to use --with-suffix when building on a
73 case-insensitive file system (such as Mac OS X HFS+). In the build
74 directory an extension is used, but not in the installed python.
75
Tim Petersb3c9af12001-11-17 00:21:57 +000076C API
77
Tim Petersf582b822001-12-11 18:51:08 +000078- New function PyDict_MergeFromSeq2() exposes the builtin dict
79 constructor's logic for updating a dictionary from an iterable object
80 producing key-value pairs.
81
Tim Peterscffed4b2001-11-29 03:26:37 +000082- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +000083 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +000084 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
85 dump core in some bad cases. This has been repaired. As a result,
86 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
87 previously went unchallenged.
88
Tim Petersb3c9af12001-11-17 00:21:57 +000089New platforms
90
91Tests
92
93Windows
94
95Mac
96
Jack Jansenffa260f2001-12-06 21:14:00 +000097- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
98 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +000099
Tim Peters84362bc2001-10-19 17:55:30 +0000100What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000101Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000102===========================
103
104Type/class unification and new-style classes
105
Guido van Rossum3d27df02001-11-15 20:27:54 +0000106- Multiple inheritance mixing new-style and classic classes in the
107 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000108
109 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000110 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000111
112 The MRO (method resolution order) for each base class is respected
113 according to its kind, but the MRO for the derived class is computed
114 using new-style MRO rules if any base clase is a new-style class.
115 This needs to be documented.
116
Tim Petersa427a2b2001-10-29 22:25:45 +0000117- The new builtin dictionary() constructor, and dictionary type, have
118 been renamed to dict. This reflects a decade of common usage.
119
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000120- dict() now accepts an iterable object producing 2-sequences. For
121 example, dict(d.items()) == d for any dictionary d. The argument,
122 and the elements of the argument, can be any iterable objects.
123
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000124- New-style classes can now have a __del__ method, which is called
125 when the instance is deleted (just like for classic classes).
126
Guido van Rossum12d955c2001-10-26 14:56:06 +0000127- Assignment to object.__dict__ is now possible, for objects that are
128 instances of new-style classes that have a __dict__ (unless the base
129 class forbids it).
130
Guido van Rossumc8e56452001-10-22 00:43:43 +0000131- Methods of built-in types now properly check for keyword arguments
132 (formerly these were silently ignored). The only built-in methods
133 that take keyword arguments are __call__, __init__ and __new__.
134
Guido van Rossum86443212001-10-27 22:28:54 +0000135- The socket function has been converted to a type; see below.
136
Tim Peters84362bc2001-10-19 17:55:30 +0000137Core and builtins
138
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000139- Assignment to __debug__ raises SyntaxError at compile-time. This
140 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000141 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000142
Guido van Rossum12d955c2001-10-26 14:56:06 +0000143- Clarified the error messages for unsupported operands to an operator
144 (like 1 + '').
145
Tim Peters84362bc2001-10-19 17:55:30 +0000146Extension modules
147
Tim Peters5ebfd362001-11-13 23:11:19 +0000148- mmap has a new keyword argument, "access", allowing a uniform way for
149 both Windows and Unix users to create read-only, write-through and
150 copy-on-write memory mappings. This was previously possible only on
151 Unix. A new keyword argument was required to support this in a
152 uniform way because the mmap() signuatures had diverged across
153 platforms. Thanks to Jay T Miller for repairing this!
154
Tim Peters169ded02001-11-03 19:57:21 +0000155- By default, the gc.garbage list now contains only those instances in
156 unreachable cycles that have __del__ methods; in 2.1 it contained all
157 instances in unreachable cycles. "Instances" here has been generalized
158 to include instances of both new-style and old-style classes.
159
Guido van Rossum12d955c2001-10-26 14:56:06 +0000160- The socket module defines a new method for socket objects,
161 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000162 send() until all data has been sent. Also, the socket function has
163 been converted to a subclassable type, like list and tuple (etc.)
164 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000165
166- Various bugfixes to the curses module. There is now a test suite
167 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000168
Guido van Rossum692adf12001-10-30 03:03:03 +0000169- binascii.b2a_base64 no longer places an arbitrary restriction of 57
170 bytes on its input.
171
Tim Peters84362bc2001-10-19 17:55:30 +0000172Library
173
Tim Peters5ebfd362001-11-13 23:11:19 +0000174- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000175 convenience function.
176
Tim Peters75335872001-11-03 19:35:43 +0000177- Symbolic group names in regular expressions must be unique. For
178 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
179 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000180 Python 2.2 detects this error at regexp compilation time;
181 previously, the error went undetected, and results were
182 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
183 pattern.subn() methods have been rewritten in C. Also, an
184 experimental function/method finditer() has been added, which works
185 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000186
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000187- Tix exposes more commands through the classes DirSelectBox,
188 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
189 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
190 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
191
Tim Peters98791af2001-10-23 01:59:54 +0000192- Traceback objects are now scanned by cyclic garbage collection, so
193 cycles created by casual use of sys.exc_info() no longer cause
194 permanent memory leaks (provided garbage collection is enabled).
195
Guido van Rossum49192142001-10-24 20:51:44 +0000196- os.extsep -- a new variable needed by the RISCOS support. It is the
197 separator used by extensions, and is '.' on all platforms except
198 RISCOS, where it is '/'. There is no need to use this variable
199 unless you have a masochistic desire to port your code to RISCOS.
200
Barry Warsaw012852b2001-11-16 16:17:27 +0000201- mimetypes.py has optional support for non-standard, but commonly
202 found types. guess_type() and guess_extension() now accept an
203 optional `strict' flag, defaulting to true, which controls whether
204 recognize non-standard types or not. A few non-standard types we
205 know about have been added. Also, when run as a script, there are
206 new -l and -e options.
207
208- statcache is now deprecated.
209
210- email.Utils.formatdate() now produces the preferred RFC 2822 style
211 dates with numeric timezones (it used to produce obsolete dates
212 hard coded to "GMT" timezone). An optional `localtime' flag is
213 added to produce dates in the local timezone, with daylight savings
214 time properly taken into account.
215
216- In pickle and cPickle, instead of masking errors in load() by
217 transforming them into SystemError, we let the original exception
218 propagate out. Also, implement support for __safe_for_unpickling__
219 in pickle, as it already was supported in cPickle.
220
Tim Peters84362bc2001-10-19 17:55:30 +0000221Tools/Demos
222
223Build
224
Barry Warsaw012852b2001-11-16 16:17:27 +0000225- The dbm module is built using libdb1 if available. The bsddb module
226 is built with libdb3 if available.
227
228- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
229
Tim Peters84362bc2001-10-19 17:55:30 +0000230C API
231
Tim Peters1fc240e2001-10-26 05:06:50 +0000232- New function PySequence_Fast_GET_SIZE() returns the size of a non-
233 NULL result from PySequence_Fast(), more quickly than calling
234 PySequence_Size().
235
Barry Warsaw012852b2001-11-16 16:17:27 +0000236- New argument unpacking function PyArg_UnpackTuple() added.
237
238- New functions PyObject_CallFunctionObjArgs() and
239 PyObject_CallMethodObjArgs() have been added to make it more
240 convenient and efficient to call functions and methods from C.
241
242- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
243 possible that this will propagate errors it didn't before.
244
245- New function PyObject_CheckReadBuffer(), which returns true if its
246 argument supports the single-segment readable buffer interface.
247
Tim Peters84362bc2001-10-19 17:55:30 +0000248New platforms
249
Guido van Rossum86443212001-10-27 22:28:54 +0000250- We've finally confirmed that this release builds on HP-UX 11.00,
251 *with* threads, and passes the test suite.
252
Tim Peters7a33d8b2001-11-05 02:51:07 +0000253- Thanks to a series of patches from Michael Muller, Python may build
254 again under OS/2 Visual Age C++.
255
Guido van Rossum49192142001-10-24 20:51:44 +0000256- Updated RISCOS port by Dietmar Schwertberger.
257
Tim Peters84362bc2001-10-19 17:55:30 +0000258Tests
259
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000260- Added a test script for the curses module. It isn't run automatically;
261 regrtest.py must be run with '-u curses' to enable it.
262
Tim Peters84362bc2001-10-19 17:55:30 +0000263Windows
264
Barry Warsaw012852b2001-11-16 16:17:27 +0000265Mac
266
267- PythonScript has been moved to unsupported and is slated to be
268 removed completely in the next release.
269
270- It should now be possible to build applets that work on both OS9 and
271 OSX.
272
273- The core is now linked with CoreServices not Carbon; as a side
274 result, default 8bit encoding on OSX is now ASCII.
275
276- Python should now build on OSX 10.1.1
277
Tim Peters84362bc2001-10-19 17:55:30 +0000278
Tim Petersabf925f2001-09-28 21:53:42 +0000279What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000280Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000281===========================
282
283Type/class unification and new-style classes
284
Guido van Rossum687ae002001-10-15 22:03:32 +0000285- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000286 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000287 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000288 remains: the __dict__ of a new-style class is a read-only proxy; you
289 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000290 __defined__ attribute of new-style types no longer exists, for lack
291 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000292 future a __cache__ may be resurrected with a similar function, if I
293 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000294
Tim Peters1c9ca872001-10-04 06:43:12 +0000295- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
296 always returned None, even when there was a class docstring).
297
298- doctest now finds and runs docstrings attached to new-style classes,
299 class methods, static methods, and properties.
300
Guido van Rossum9074ef62001-10-16 21:34:49 +0000301Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000302
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000303- A very subtle syntactical pitfall in list comprehensions was fixed.
304 For example: [a+b for a in 'abc', for b in 'def']. The comma in
305 this example is a mistake. Previously, this would silently let 'a'
306 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
307 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
308 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
309 Note that [a for a in <singleton>] is a convoluted way to say
310 [<singleton>] anyway, so it's not like any expressiveness is lost.
311
Guido van Rossum9074ef62001-10-16 21:34:49 +0000312- getattr(obj, name, default) now only catches AttributeError, as
313 documented, rather than returning the default value for all
314 exceptions (which could mask bugs in a __getattr__ hook, for
315 example).
316
Fred Drakecb7a6b52001-10-22 18:41:51 +0000317- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000318 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000319 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000320 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000321
Guido van Rossum1c486092001-10-19 02:05:35 +0000322- unicode(obj) now behaves more like str(obj), accepting arbitrary
323 objects, and calling a __unicode__ method if it exists.
324 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000325 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000326
Barry Warsawf6fb1712001-10-19 05:35:40 +0000327- isinstance() now allows any object as the first argument and a
328 class, a type or something with a __bases__ tuple attribute for the
329 second argument. The second argument may also be a tuple of a
330 class, type, or something with __bases__, in which case isinstance()
331 will return true if the first argument is an instance of any of the
332 things contained in the second argument tuple. E.g.
333
334 isinstance(x, (A, B))
335
336 returns true if x is an instance of A or B.
337
Guido van Rossum9074ef62001-10-16 21:34:49 +0000338Extension modules
339
340- thread.start_new_thread() now returns the thread ID (previously None).
341
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000342- binascii has now two quopri support functions, a2b_qp and b2a_qp.
343
Guido van Rossumc524d952001-10-19 01:31:59 +0000344- readline now supports setting the startup_hook and the
345 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000346
Guido van Rossumc524d952001-10-19 01:31:59 +0000347- os and posix supports chroot(), setgroups() and unsetenv() where
348 available. The stat(), fstat(), statvfs() and fstatvfs() functions
349 now return "pseudo-sequences" -- the various fields can now be
350 accessed as attributes (e.g. os.stat("/").st_mtime) but for
351 backwards compatibility they also behave as a fixed-length sequence.
352 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000353 attributes.
354
355- time: localtime(), gmtime() and strptime() now return a
356 pseudo-sequence similar to the os.stat() return value, with
357 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000358
Guido van Rossum9074ef62001-10-16 21:34:49 +0000359- Decompression objects in the zlib module now accept an optional
360 second parameter to decompress() that specifies the maximum amount
361 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000362
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000363- optional SSL support in the socket module now exports OpenSSL
364 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
365 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000366 automatically seed its PRNG. Also, the keyfile and certfile
367 arguments to socket.ssl() are now optional.
368
369- posixmodule (and by extension, the os module on POSIX platforms) now
370 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000371
Guido van Rossum9074ef62001-10-16 21:34:49 +0000372Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000373
Tim Peters7402f792001-10-02 03:53:41 +0000374- doctest now excludes functions and classes not defined by the module
375 being tested, thanks to Tim Hochberg.
376
Fred Drakecb7a6b52001-10-22 18:41:51 +0000377- HotShot, a new profiler implemented using a C-based callback, has
378 been added. This substantially reduces the overhead of profiling,
379 but it is still quite preliminary. Support modules and
380 documentation will be added in upcoming releases (before 2.2 final).
381
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000382- profile now produces correct output in situations where an exception
383 raised in Python is cleared by C code (e.g. hasattr()). This used
384 to cause wrong output, including spurious claims of recursive
385 functions and attribution of time spent to the wrong function.
386
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000387 The code and documentation for the derived OldProfile and HotProfile
388 profiling classes was removed. The code hasn't worked for years (if
389 you tried to use them, they raised exceptions). OldProfile
390 intended to reproduce the behavior of the profiler Python used more
391 than 7 years ago, and isn't interesting anymore. HotProfile intended
392 to provide a faster profiler (but producing less information), and
393 that's a worthy goal we intend to meet via a different approach (but
394 without losing information).
395
Tim Peterscce092d2001-10-09 05:31:56 +0000396- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000397 a much better system-specific calibration constant. The constant can
398 now be specified in an instance constructor, or as a Profile class or
399 instance variable, instead of by editing profile.py's source code.
400 Calibration must still be done manually (see the docs for the profile
401 module).
402
403 Note that Profile.calibrate() must be overriden by subclasses.
404 Improving the accuracy required exploiting detailed knowledge of
405 profiler internals; the earlier method abstracted away the details
406 and measured a simplified model instead, but consequently computed
407 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000408
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000409- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000410 which indicates whether output is intended for the header 'Q'
411 encoding.
412
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000413- The SocketServer.ThreadingMixIn class now closes the request after
414 finish_request() returns. (Not when it errors out though.)
415
Barry Warsawf6fb1712001-10-19 05:35:40 +0000416- The nntplib module's NNTP.body() method has grown a `file' argument
417 to allow saving the message body to a file.
418
419- The email package has added a class email.Parser.HeaderParser which
420 only parses headers and does not recurse into the message's body.
421 Also, the module/class MIMEAudio has been added for representing
422 audio data (contributed by Anthony Baxter).
423
424- ftplib should be able to handle files > 2GB.
425
426- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
427 ON, and OFF.
428
Fred Drakecb7a6b52001-10-22 18:41:51 +0000429- xml.dom.minidom NodeList objects now support the length attribute
430 and item() method as required by the DOM specifications.
431
Guido van Rossumed554f62001-10-02 23:15:37 +0000432Tools/Demos
433
434- Demo/dns was removed. It no longer serves any purpose; a package
435 derived from it is now maintained by Anthony Baxter, see
436 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000437
Barry Warsawf6fb1712001-10-19 05:35:40 +0000438- The freeze tool has been made more robust, and two new options have
439 been added: -X and -E.
440
Tim Petersabf925f2001-09-28 21:53:42 +0000441Build
442
Barry Warsawf6fb1712001-10-19 05:35:40 +0000443- configure will use CXX in LINKCC if CXX is used to build main() and
444 the system requires to link a C++ main using the C++ compiler.
445
Tim Petersabf925f2001-09-28 21:53:42 +0000446C API
447
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000448- The documentation for the tp_compare slot is updated to require that
449 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
450 not correct. This is not yet enforced but will be enforced in
451 Python 2.3; even later, we may use -2 to indicate errors and +2 for
452 "NotImplemented". Right now, -1 should be used for an error return.
453
Tim Petersd38b1c72001-09-30 05:09:37 +0000454- PyLong_AsLongLong() now accepts int (as well as long) arguments.
455 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
456 as long) arguments.
457
Guido van Rossum3c288632001-10-16 21:13:49 +0000458- PyThread_start_new_thread() now returns a long int giving the thread
459 ID, if one can be calculated; it returns -1 for error, 0 if no
460 thread ID is calculated (this is an incompatible change, but only
461 the thread module used this API). This code has only really been
462 tested on Linux and Windows; other platforms please beware (and
463 report any bugs or strange behavior).
464
Guido van Rossum1c486092001-10-19 02:05:35 +0000465- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
466 input.
467
Tim Petersabf925f2001-09-28 21:53:42 +0000468New platforms
469
470Tests
471
472Windows
473
Tim Peters04cf1d32001-10-09 22:39:40 +0000474- Installer: If you install IDLE, and don't disable file-extension
475 registration, a new "Edit with IDLE" context (right-click) menu entry
476 is created for .py and .pyw files.
477
Tim Peters1ce3cf72001-10-01 17:58:40 +0000478- The signal module now supports SIGBREAK on Windows, thanks to Steven
479 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
480 action remains to call Win32 ExitProcess(). This can be changed via
481 signal.signal(). For example:
482
483 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
484 # (SIGINT) behavior.
485 import signal
486 signal.signal(signal.SIGBREAK,
487 signal.default_int_handler)
488
489 try:
490 while 1:
491 pass
492 except KeyboardInterrupt:
493 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
494 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
495 # program without the possibility for any Python-level cleanup).
496 print "Clean exit"
497
Tim Petersabf925f2001-09-28 21:53:42 +0000498
Tim Petersb07352e2001-09-08 01:25:47 +0000499What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000500Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000501===========================
502
Guido van Rossum808eea72001-09-25 04:15:41 +0000503Type/class unification and new-style classes
504
505- pydoc and inspect are now aware of new-style classes;
506 e.g. help(list) at the interactive prompt now shows proper
507 documentation for all operations on list objects.
508
509- Applications using Jim Fulton's ExtensionClass module can now safely
510 be used with Python 2.2. In particular, Zope 2.4.1 now works with
511 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
512 examples also work again. It is hoped that Gtk and Boost also work
513 with 2.2a4 and beyond. (If you can confirm this, please write
514 webmaster@python.org; if there are still problems, please open a bug
515 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000516
Tim Peters66c1a522001-09-24 21:17:50 +0000517- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
518 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
519 in the constructed property object. fget, fset and fdel weren't
520 discoverable from Python in 2.2a3. __doc__ is new, and allows to
521 associate a docstring with a property.
522
Guido van Rossum808eea72001-09-25 04:15:41 +0000523- Comparison overloading is now more completely implemented. For
524 example, a str subclass instance can properly be compared to a str
525 instance, and it can properly overload comparison. Ditto for most
526 other built-in object types.
527
528- The repr() of new-style classes has changed; instead of <type
529 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
530 *except* for built-in types, which are still rendered as <type
531 'Foo'> (to avoid upsetting existing code that might parse or
532 otherwise rely on repr() of certain type objects).
533
534- The repr() of new-style objects is now always <Foo object at XXX>;
535 previously, it was sometimes <Foo instance at XXX>.
536
537- For new-style classes, what was previously called __getattr__ is now
538 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000539 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000540 one in classic classes is defined which is called only if regular
541 attribute access raises AttributeError; to catch *all* attribute
542 access, you can use __getattribute__ (for new-style classes). If
543 both are defined, __getattribute__ is called first, and if it raises
544 AttributeError, __getattr__ is called.
545
546- The __class__ attribute of new-style objects can be assigned to.
547 The new class must have the same C-level object layout as the old
548 class.
549
550- The builtin file type can be subclassed now. In the usual pattern,
551 "file" is the name of the builtin type, and file() is a new builtin
552 constructor, with the same signature as the builtin open() function.
553 file() is now the preferred way to open a file.
554
555- Previously, __new__ would only see sequential arguments passed to
556 the type in a constructor call; __init__ would see both sequential
557 and keyword arguments. This made no sense whatsoever any more, so
558 now both __new__ and __init__ see all arguments.
559
560- Previously, hash() applied to an instance of a subclass of str or
561 unicode always returned 0. This has been repaired.
562
563- Previously, an operation on an instance of a subclass of an
564 immutable type (int, long, float, complex, tuple, str, unicode),
565 where the subtype didn't override the operation (and so the
566 operation was handled by the builtin type), could return that
567 instance instead a value of the base type. For example, if s was of
568 a str sublass type, s[:] returned s as-is. Now it returns a str
569 with the same value as s.
570
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000571- Provisional support for pickling new-style objects has been added.
572
Guido van Rossum808eea72001-09-25 04:15:41 +0000573Core
574
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000575- file.writelines() now accepts any iterable object producing strings.
576
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000577- PyUnicode_FromEncodedObject() now works very much like
578 PyObject_Str(obj) in that it tries to use __str__/tp_str
579 on the object if the object is not a string or buffer. This
580 makes unicode() behave like str() when applied to non-string/buffer
581 objects.
582
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000583- PyFile_WriteObject now passes Unicode objects to the file's write
584 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000585 of a print statement must support Unicode objects, i.e. they must
586 at least convert them into ASCII strings.
587
Guido van Rossum624c8af2001-09-18 15:21:04 +0000588- Thread scheduling on Solaris should be improved; it is no longer
589 necessary to insert a small sleep at the start of a thread in order
590 to let other runnable threads be scheduled.
591
Tim Petersb07352e2001-09-08 01:25:47 +0000592Library
593
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000594- StringIO.StringIO instances and cStringIO.StringIO instances support
595 read character buffer compatible objects for their .write() methods.
596 These objects are converted to strings and then handled as such
597 by the instances.
598
Barry Warsaw2f600732001-09-24 04:28:10 +0000599- The "email" package has been added. This is basically a port of the
600 mimelib package <http://sf.net/projects/mimelib> with API changes
601 and some implementations updated to use iterators and generators.
602
Tim Peters8a9c2842001-09-22 21:30:22 +0000603- difflib.ndiff() and difflib.Differ.compare() are generators now. This
604 restores the ability of Tools/scripts/ndiff.py to start producing output
605 before the entire comparison is complete.
606
Barry Warsaw58b072d2001-09-22 04:44:21 +0000607- StringIO.StringIO instances and cStringIO.StringIO instances support
608 iteration just like file objects (i.e. their .readline() method is
609 called for each iteration until it returns an empty string).
610
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000611- The codecs module has grown four new helper APIs to access
612 builtin codecs: getencoder(), getdecoder(), getreader(),
613 getwriter().
614
Guido van Rossum624c8af2001-09-18 15:21:04 +0000615- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
616 simplifies writing XML RPC servers.
617
Barry Warsaw647d5e82001-09-28 17:01:02 +0000618- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000619 after interpretation of symbolic links. On non-Unix systems, this
620 is an alias for os.path.abspath().
621
Tim Peters16a77ad2001-09-08 04:00:12 +0000622- operator.indexOf() (PySequence_Index() in the C API) now works with any
623 iterable object.
624
Guido van Rossum624c8af2001-09-18 15:21:04 +0000625- smtplib now supports various authentication and security features of
626 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000627
Guido van Rossum624c8af2001-09-18 15:21:04 +0000628- hmac: a new module implementing keyed hashing for message
629 authentication.
630
631- mimetypes now recognizes more extensions and file types. At the
632 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000633
Guido van Rossum624c8af2001-09-18 15:21:04 +0000634- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000635 Python 2.2 bytecode generation. It has also been promoted from a
636 Tool to a standard library package. (Tools/compiler still exists as
637 a sample driver.)
638
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000639Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000640
Tim Petersb07352e2001-09-08 01:25:47 +0000641Build
642
Guido van Rossum624c8af2001-09-18 15:21:04 +0000643- Large file support (LFS) is now automatic when the platform supports
644 it; no more manual configuration tweaks are needed. On Linux, at
645 least, it's possible to have a system whose C library supports large
646 files but whose kernel doesn't; in this case, large file support is
647 still enabled but doesn't do you any good unless you upgrade your
648 kernel or share your Python executable with another system whose
649 kernel has large file support.
650
651- The configure script now supplies plausible defaults in a
652 cross-compilation environment. This doesn't mean that the supplied
653 values are always correct, or that cross-compilation now works
654 flawlessly -- but it's a first step (and it shuts up most of
655 autoconf's warnings about AC_TRY_RUN).
656
657- The Unix build is now a bit less chatty, courtesy of the parser
658 generator. The build is completely silent (except for errors) when
659 using "make -s", thanks to a -q option to setup.py.
660
Tim Petersb07352e2001-09-08 01:25:47 +0000661C API
662
Guido van Rossum624c8af2001-09-18 15:21:04 +0000663- The "structmember" API now supports some new flag bits to deny read
664 and/or write access to attributes in restricted execution mode.
665
Tim Petersb07352e2001-09-08 01:25:47 +0000666New platforms
667
Guido van Rossum624c8af2001-09-18 15:21:04 +0000668- Compaq's iPAQ handheld, running the "familiar" Linux distribution
669 (http://familiar.handhelds.org).
670
Tim Petersb07352e2001-09-08 01:25:47 +0000671Tests
672
Tim Peters8a9c2842001-09-22 21:30:22 +0000673- The "classic" standard tests, which work by comparing stdout to
674 an expected-output file under Lib/test/output/, no longer stop at
675 the first mismatch. Instead the test is run to completion, and a
676 variant of ndiff-style comparison is used to report all differences.
677 This is much easier to understand than the previous style of reporting.
678
679- The unittest-based standard tests now use regrtest's test_main()
680 convention, instead of running as a side-effect of merely being
681 imported. This allows these tests to be run in more natural and
682 flexible ways as unittests, outside the regrtest framework.
683
684- regrtest.py is much better integrated with unittest and doctest now,
685 especially in regard to reporting errors.
686
Tim Petersb07352e2001-09-08 01:25:47 +0000687Windows
688
Guido van Rossum624c8af2001-09-18 15:21:04 +0000689- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000690 that support it (NTFS under Windows 2000). See "What's New in
691 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000692
Tim Petersb07352e2001-09-08 01:25:47 +0000693
Tim Petersedc99312001-08-22 21:36:50 +0000694What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000695Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000696===========================
697
698Core
699
Tim Peters9fffa3e2001-09-04 05:14:19 +0000700- Conversion of long to float now raises OverflowError if the long is too
701 big to represent as a C double.
702
Tim Peters32f453e2001-09-03 08:35:41 +0000703- The 3-argument builtin pow() no longer allows a third non-None argument
704 if either of the first two arguments is a float, or if both are of
705 integer types and the second argument is negative (in which latter case
706 the arguments are converted to float, so this is really the same
707 restriction).
708
Tim Peters5d2b77c2001-09-03 05:47:38 +0000709- The builtin dir() now returns more information, and sometimes much
710 more, generally naming all attributes of an object, and all attributes
711 reachable from the object via its class, and from its class's base
712 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
713 an empty list. In 2.2a3,
714
715 >>> dir([])
716 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
717 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
718 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
719 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
720 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
721 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
722 'reverse', 'sort']
723
724 dir(module) continues to return only the module's attributes, though.
725
Tim Petersbdee63f2001-09-02 03:40:59 +0000726- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000727 than raising OverflowError. This is a partial implementation of PEP
728 237. You can use -Wdefault::OverflowWarning to enable a warning for
729 this situation, and -Werror::OverflowWarning to revert to the old
730 OverflowError exception.
731
Guido van Rossum61c345f2001-09-04 03:26:15 +0000732- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000733 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000734 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
735 -Qold, meaning the / operator has its classic meaning and no
736 warnings are issued. Using -Qwarn issues a run-time warning about
737 all uses of classic division for int and long arguments; -Qwarnall
738 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +0000739 (for use with fixdiv.py).
740 [Note: the remainder of this paragraph (preserved below) became
741 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
742 <obsolete>
743 Using -Qnew is questionable; it turns on new division by default, but
744 only in the __main__ module. You can usefully combine -Qwarn or
745 -Qwarnall and -Qnew: this gives the __main__ module new division, and
746 warns about classic division everywhere else.
747 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +0000748
Tim Petersbdee63f2001-09-02 03:40:59 +0000749- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000750 long, float, str, unicode, and tuple. (The types complex, list and
751 dictionary can also be subclassed; this was introduced earlier.)
752 Note that restrictions apply when subclassing immutable built-in
753 types: you can only affect the value of the instance by overloading
754 __new__. You can add mutable attributes, and the subclass instances
755 will have a __dict__ attribute, but you cannot change the "value"
756 (as implemented by the base class) of an immutable subclass instance
757 once it is created.
758
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000759- The dictionary constructor now takes an optional argument, a
760 mapping-like object, and initializes the dictionary from its
761 (key, value) pairs.
762
Tim Petersbdee63f2001-09-02 03:40:59 +0000763- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000764 "cooperative super calls" in a multiple inheritance setting. For an
765 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
766
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000767- A new built-in type, property, has been added. This enables the
768 creation of "properties". These are attributes implemented by
769 getter and setter functions (or only one of these for read-only or
770 write-only attributes), without the need to override __getattr__.
771 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000772
Tim Petersbdee63f2001-09-02 03:40:59 +0000773- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000774 liberalized, to allow leading zeroes. Examples of literals now
775 legal that were SyntaxErrors before:
776
777 00.0 0e3 0100j 07.5 00000000000000000008.
778
Tim Petersbdee63f2001-09-02 03:40:59 +0000779- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000780 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
781
Tim Petersedc99312001-08-22 21:36:50 +0000782Library
783
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000784- telnetlib includes symbolic names for the options, and support for
785 setting an option negotiation callback.
786
Tim Petersa40c7932001-09-05 22:36:56 +0000787- The new C standard no longer requires that math libraries set errno to
788 ERANGE on overflow. For platform libraries that exploit this new
789 freedom, Python's overflow-checking was wholly broken. A new overflow-
790 checking scheme attempts to repair that, but may not be reliable on all
791 platforms (C doesn't seem to provide anything both useful and portable
792 in this area anymore).
793
Martin v. Löwis44f86962001-09-05 13:44:54 +0000794- Asynchronous timeout actions are available through the new class
795 threading.Timer.
796
Tim Peters78526162001-09-05 00:53:45 +0000797- math.log and math.log10 now return sensible results for even huge
798 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
799
Tim Petersbdee63f2001-09-02 03:40:59 +0000800- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000801 currently held. See the docs for the imp module.
802
Tim Petersbdee63f2001-09-02 03:40:59 +0000803- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000804 dumps containing ints written on platforms where Python ints are 8 bytes.
805 When read on a box where Python ints are 4 bytes, such values are
806 converted to Python longs.
807
Tim Petersbdee63f2001-09-02 03:40:59 +0000808- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000809 code objects is no longer allowed. This plugs a security hole.
810
Steve Purcell6091cd62001-09-06 16:05:17 +0000811- unittest.TestResult instances no longer store references to tracebacks
812 generated by test failures. This prevents unexpected dangling references
813 to objects that should be garbage collected between tests.
814
Tim Petersedc99312001-08-22 21:36:50 +0000815Tools
816
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000817- Tools/scripts/fixdiv.py has been added which can be used to fix
818 division operators as per PEP 238.
819
Tim Petersedc99312001-08-22 21:36:50 +0000820Build
821
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000822- If you are an adventurous person using Mac OS X you may want to look at
823 Mac/OSX. There is a Makefile there that will build Python as a real Mac
824 application, which can be used for experimenting with Carbon or Cocoa.
825 Discussion of this on pythonmac-sig, please.
826
Tim Peters7eea37e2001-09-04 22:08:56 +0000827C API
828
829- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000830
Tim Peters9fffa3e2001-09-04 05:14:19 +0000831- Note that PyLong_AsDouble can fail! This has always been true, but no
832 callers checked for it. It's more likely to fail now, because overflow
833 errors are properly detected now. The proper way to check:
834
835 double x = PyLong_AsDouble(some_long_object);
836 if (x == -1.0 && PyErr_Occurred()) {
837 /* The conversion failed. */
838 }
839
Tim Petersbdee63f2001-09-02 03:40:59 +0000840- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000841 compile but will not participate in GC. To upgrade an extension
842 module:
843
844 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000845
Neil Schemenauer4042c692001-08-30 15:38:01 +0000846 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
847 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000848
Neil Schemenauer4042c692001-08-30 15:38:01 +0000849 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
850 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000851
Neil Schemenauer4042c692001-08-30 15:38:01 +0000852 - remove PyGC_HEAD_SIZE from object size calculations
853
854 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
855
Tim Petersbdee63f2001-09-02 03:40:59 +0000856- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000857 These can be used safely to construct string objects from a
858 sprintf-style format string (similar to the format string supported
859 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000860
Tim Petersedc99312001-08-22 21:36:50 +0000861New platforms
862
Tim Petersb7da0902001-09-02 23:01:43 +0000863- Stephen Hansen contributed patches sufficient to get a clean compile
864 under Borland C (Windows), but he reports problems running it and ran
865 out of time to complete the port. Volunteers? Expect a MemoryError
866 when importing the types module; this is probably shallow, and
867 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000868
Tim Petersedc99312001-08-22 21:36:50 +0000869Tests
870
871Windows
872
Tim Peters6e13a562001-09-06 00:32:15 +0000873- Large file support is now enabled on Win32 platforms as well as on
874 Win64. This means that, for example, you can use f.tell() and f.seek()
875 to manipulate files larger than 2 gigabytes (provided you have enough
876 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000877 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
878 filesize limit, and large file support makes no difference there.
879 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
880 NTFS has no practical limit on file size, and files of any size can be
881 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000882
Tim Petersbdee63f2001-09-02 03:40:59 +0000883- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000884 points to command.com (patch from Brian Quinlan).
885
Tim Petersedc99312001-08-22 21:36:50 +0000886
Tim Peters20f51a72001-07-21 02:31:40 +0000887What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000888Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000889===========================
890
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000891Build
892
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000893- Tim Peters developed a brand new Windows installer using Wise 8.1,
894 generously donated to us by Wise Solutions.
895
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000896- configure supports a new option --enable-unicode, with the values
897 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
898 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000899
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000900- A new configure option --enable-framework builds a Mac OS X framework,
901 which "make frameworkinstall" will install. This provides a starting
902 point for more mac-like functionality, join pythonmac-sig@python.org
903 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000904
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000905- The NeXT platform is no longer supported.
906
907- The `new' module is now statically linked.
908
Tim Peters0afb6092001-08-15 06:06:44 +0000909Tools
910
911- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000912 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000913 the module docstring for details.
914
Tim Peters20f51a72001-07-21 02:31:40 +0000915Tests
916
Tim Peters5e824c32001-08-12 22:25:01 +0000917- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000918 platforms, allowing to give clearer test result output. regrtest
919 also has optional --use/-u switch to run normally disabled tests
920 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000921
Tim Peters20f51a72001-07-21 02:31:40 +0000922- Several new tests in the standard test suite, with special thanks to
923 Nick Mathewson.
924
925Core
926
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000927- The floor division operator // has been added as outlined in PEP
928 238. The / operator still provides classic division (and will until
929 Python 3.0) unless "from __future__ import division" is included, in
930 which case the / operator will provide true division. The operator
931 module provides truediv() and floordiv() functions. Augmented
932 assignment variants are included, as are the equivalent overloadable
933 methods and C API methods. See the PEP for a full discussion:
934 <http://python.sf.net/peps/pep-0238.html>
935
Tim Peters6cd6a822001-08-17 22:11:27 +0000936- Future statements are now effective in simulated interactive shells
937 (like IDLE). This should "just work" by magic, but read Michael
938 Hudson's "Future statements in simulated shells" PEP 264 for full
939 details: <http://python.sf.net/peps/pep-0264.html>.
940
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000941- The type/class unification (PEP 252-253) was integrated into the
942 trunk and is not so tentative any more (the exact specification of
943 some features is still tentative). A lot of work has done on fixing
944 bugs and adding robustness and features (performance still has to
945 come a long way).
946
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000947- Warnings about a mismatch in the Python API during extension import
948 now use the Python warning framework (which makes it possible to
949 write filters for these warnings).
950
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000951- A function's __dict__ (aka func_dict) will now always be a
952 dictionary. It used to be possible to delete it or set it to None,
953 but now both actions raise TypeErrors. It is still legal to set it
954 to a dictionary object. Getting func.__dict__ before any attributes
955 have been assigned now returns an empty dictionary instead of None.
956
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000957- A new command line option, -E, was added which disables the use of
958 all environment variables, or at least those that are specifically
959 significant to Python. Usually those have a name starting with
960 "PYTHON". This was used to fix a problem where the tests fail if
961 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
962 older distribution.
963
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000964Library
965
Tim Peters5e824c32001-08-12 22:25:01 +0000966- New class Differ and new functions ndiff() and restore() in difflib.py.
967 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000968 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000969
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000970- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
971 value using the minimal quoting required for the value; more
972 reliable than using xml.sax.saxutils.escape() for attribute values.
973
974- Readline completion support for cmd.Cmd was added.
975
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000976- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
977
978- Added function threading.BoundedSemaphore()
979
980- Added Ka-Ping Yee's cgitb.py module.
981
982- The `new' module now exposes the CO_xxx flags.
983
Martin v. Löwis560da622001-11-24 09:24:51 +0000984- The gc module offers the get_referents function.
985
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000986New platforms
987
988C API
989
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000990- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
991 which provide a cross-platform implementations for the
992 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
993 the standard sprintf() and vsprintf() C lib APIs, these versions
994 apply bounds checking on the used buffer which enhances protection
995 against buffer overruns.
996
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000997- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000998 and extensions using different Unicode widths is rendered next to
999 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001000 will result in an ImportError. Unicode extensions writers must make
1001 sure to check the Unicode width compatibility in their extensions by
1002 using at least one of the mangled Unicode APIs in the extension.
1003
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001004- Two new flags METH_NOARGS and METH_O are available in method definition
1005 tables to simplify implementation of methods with no arguments and a
1006 single untyped argument. Calling such methods is more efficient than
1007 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1008 deprecated.
1009
Tim Petersc1731372001-08-04 08:12:36 +00001010Windows
1011
1012- "import module" now compiles module.pyw if it exists and nothing else
1013 relevant is found.
1014
Tim Peters20f51a72001-07-21 02:31:40 +00001015
Guido van Rossum55a78992001-07-17 17:22:32 +00001016What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001017Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001018===========================
1019
1020Core
Tim Petersa814db52001-05-14 07:05:58 +00001021
Tim Peters6d6c1a32001-08-02 04:15:00 +00001022- TENTATIVELY, a large amount of code implementing much of what's
1023 described in PEP 252 (Making Types Look More Like Classes) and PEP
1024 253 (Subtyping Built-in Types) was added. This will be released
1025 with Python 2.2a1. Documentation will be provided separately
1026 through http://www.python.org/2.2/. The purpose of releasing this
1027 with Python 2.2a1 is to test backwards compatibility. It is
1028 possible, though not likely, that a decision is made not to release
1029 this code as part of 2.2 final, if any serious backwards
1030 incompapatibilities are found during alpha testing that cannot be
1031 repaired.
1032
Guido van Rossum55a78992001-07-17 17:22:32 +00001033- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001034 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001035 more 'yield' statements. See PEP 255. Since this adds a new
1036 keyword to the language, this feature must be enabled by including a
1037 future statement: "from __future__ import generators" (see PEP 236).
1038 Generators will become a standard feature in a future release
1039 (probably 2.3). Without this future statement, 'yield' remains an
1040 ordinary identifier, but a warning is issued each time it is used.
1041 (These warnings currently don't conform to the warnings framework of
1042 PEP 230; we intend to fix this in 2.2a2.)
1043
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001044- The UTF-16 codec was modified to be more RFC compliant. It will now
1045 only remove BOM characters at the start of the string and then
1046 only if running in native mode (UTF-16-LE and -BE won't remove a
1047 leading BMO character).
1048
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001049- Strings now have a new method .decode() to complement the already
1050 existing .encode() method. These two methods provide direct access
1051 to the corresponding decoders and encoders of the registered codecs.
1052
1053 To enhance the usability of the .encode() method, the special
1054 casing of Unicode object return values was dropped (Unicode objects
1055 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001056
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001057 Both methods will now return whatever the codec in charge of the
1058 requested encoding returns as object, e.g. Unicode codecs will
1059 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1060 will return u"äöü"). This enables codec writer to create codecs
1061 for various simple to use conversions.
1062
1063 New codecs were added to demonstrate these new features (the .encode()
1064 and .decode() columns indicate the type of the returned objects):
1065
1066 Name | .encode() | .decode() | Description
1067 ----------------------------------------------------------------------
1068 uu | string | string | UU codec (e.g. for email)
1069 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001070 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001071 zlib | string | string | zlib compression
1072 hex | string | string | 2-byte hex codec
1073 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1074
Mark Hammond2a0af792001-05-14 03:09:36 +00001075- Some operating systems now support the concept of a default Unicode
1076 encoding for file system operations. Notably, Windows supports 'mbcs'
1077 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001078 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001079 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001080
1081 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001082 functions that return filenames (such as os.listdir()) to return Python
1083 string objects pre-encoded using the default file system encoding for
1084 the platform. As this encoding is likely to be different from Python's
1085 default encoding, converting this name to a Unicode object before passing
1086 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001087 would attempt to use its default encoding (generally ASCII) rather than
1088 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001089
Tim Petersa814db52001-05-14 07:05:58 +00001090 In general, this change simply removes surprises when working with
1091 Unicode and the file system, making these operations work as you expect,
1092 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001093 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001094
Tim Peters61dff2b2001-05-08 15:43:37 +00001095- Float (and complex) literals in source code were evaluated to full
1096 precision only when running from a .py file; the same code loaded from a
1097 .pyc (or .pyo) file could suffer numeric differences starting at about the
1098 12th significant decimal digit. For example, on a machine with IEEE-754
1099 floating arithmetic,
1100
1101 x = 9007199254740992.0
1102 print long(x)
1103
1104 printed 9007199254740992 if run directly from .py, but 9007199254740000
1105 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1106 str(float) instead of repr(float) when building code objects. marshal
1107 now uses repr(float) instead, which should reproduce floats to full
1108 machine precision (assuming the platform C float<->string I/O conversion
1109 functions are of good quality).
1110
1111 This may cause floating-point results to change in some cases, and
1112 usually for the better, but may also cause numerically unstable
1113 algorithms to break.
1114
Tim Peters2f228e72001-05-13 00:19:31 +00001115- The implementation of dicts suffers fewer collisions, which has speed
1116 benefits. However, the order in which dict entries appear in dict.keys(),
1117 dict.values() and dict.items() may differ from previous releases for a
1118 given dict. Nothing is defined about this order, so no program should
1119 rely on it. Nevertheless, it's easy to write test cases that rely on the
1120 order by accident, typically because of printing the str() or repr() of a
1121 dict to an "expected results" file. See Lib/test/test_support.py's new
1122 sortdict(dict) function for a simple way to display a dict in sorted
1123 order.
1124
Tim Peters7a3bfc32001-06-12 01:22:22 +00001125- Many other small changes to dicts were made, resulting in faster
1126 operation along the most common code paths.
1127
Guido van Rossum10315822001-05-01 20:54:30 +00001128- Dictionary objects now support the "in" operator: "x in dict" means
1129 the same as dict.has_key(x).
1130
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001131- The update() method of dictionaries now accepts generic mapping
1132 objects. Specifically the argument object must support the .keys()
1133 and __getitem__() methods. This allows you to say, for example,
1134 {}.update(UserDict())
1135
Guido van Rossum10315822001-05-01 20:54:30 +00001136- Iterators were added; this is a generalized way of providing values
1137 to a for loop. See PEP 234. There's a new built-in function iter()
1138 to return an iterator. There's a new protocol to get the next value
1139 from an iterator using the next() method (in Python) or the
1140 tp_iternext slot (in C). There's a new protocol to get iterators
1141 using the __iter__() method (in Python) or the tp_iter slot (in C).
1142 Iterating (i.e. a for loop) over a dictionary generates its keys.
1143 Iterating over a file generates its lines.
1144
Tim Petersf553f892001-05-01 20:45:31 +00001145- The following functions were generalized to work nicely with iterator
1146 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001147 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001148 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1149 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001150 join() method of strings
1151 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001152 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1153 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001154 right-hand side of assignment statements with multiple targets, such as
1155 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001156
Tim Petersd85e1022001-05-11 21:51:48 +00001157- Accessing module attributes is significantly faster (for example,
1158 random.random or os.path or yourPythonModule.yourAttribute).
1159
Tim Peterse63415e2001-05-08 04:38:29 +00001160- Comparing dictionary objects via == and != is faster, and now works even
1161 if the keys and values don't support comparisons other than ==.
1162
Tim Peters95bf9392001-05-10 08:32:44 +00001163- Comparing dictionaries in ways other than == and != is slower: there were
1164 insecurities in the dict comparison implementation that could cause Python
1165 to crash if the element comparison routines for the dict keys and/or
1166 values mutated the dicts. Making the code bulletproof slowed it down.
1167
Tim Peterseb28ef22001-06-02 05:27:19 +00001168- Collisions in dicts are resolved via a new approach, which can help
1169 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001170 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001171 faster now. Thanks to Christian Tismer for pointing out the cause and
1172 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001173
Tim Peters52e155e2001-06-16 05:42:57 +00001174- repr() is much faster for large containers (dict, list, tuple).
1175
1176
Tim Petersa814db52001-05-14 07:05:58 +00001177Library
1178
Fred Drake960fdf92001-07-20 18:38:26 +00001179- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1180 were added to the string module. These a locale-indenpendent
1181 constants, unlike letters, lowercase, and uppercase. These are now
1182 use in appropriate locations in the standard library.
1183
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001184- The flags used in dlopen calls can now be configured using
1185 sys.setdlopenflags and queried using sys.getdlopenflags.
1186
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001187- Fredrik Lundh's xmlrpclib is now a standard library module. This
1188 provides full client-side XML-RPC support. In addition,
1189 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1190 one asyncore-based). Thanks to Eric Raymond for the documentation.
1191
Guido van Rossum643d3912001-07-05 14:46:25 +00001192- The xrange() object is simplified: it no longer supports slicing,
1193 repetition, comparisons, efficient 'in' checking, the tolist()
1194 method, or the start, stop and step attributes. See PEP 260.
1195
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001196- A new function fnmatch.filter to filter lists of file names was added.
1197
Barry Warsawffd674d2001-05-22 16:00:10 +00001198- calendar.py uses month and day names based on the current locale.
1199
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001200- strop is now *really* obsolete (this was announced before with 1.6),
1201 and issues DeprecationWarning when used (except for the four items
1202 that are still imported into string.py).
1203
Tim Petersa814db52001-05-14 07:05:58 +00001204- Cookie.py now sorts key+value pairs by key in output strings.
1205
1206- pprint.isrecursive(object) didn't correctly identify recursive objects.
1207 Now it does.
1208
Tim Peters95b3f782001-05-14 18:39:41 +00001209- pprint functions now much faster for large containers (tuple, list, dict).
1210
Tim Peters7b9542a2001-06-10 23:40:19 +00001211- New 'q' and 'Q' format codes in the struct module, corresponding to C
1212 types "long long" and "unsigned long long" (on Windows, __int64). In
1213 native mode, these can be used only when the platform C compiler supports
1214 these types (when HAVE_LONG_LONG is #define'd by the Python config
1215 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001216 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1217 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001218
Guido van Rossum83213cc2001-06-12 16:48:52 +00001219- The site module installs a new built-in function 'help' that invokes
1220 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1221 it displays a message reminding the user to use 'help()' or
1222 'help(object)'.
1223
Tim Petersa814db52001-05-14 07:05:58 +00001224Tests
1225
1226- New test_mutants.py runs dict comparisons where the key and value
1227 comparison operators mutute the dicts randomly during comparison. This
1228 rapidly causes Python to crash under earlier releases (not for the faint
1229 of heart: it can also cause Win9x to freeze or reboot!).
1230
1231- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001232 pprint.isreadable() return sensible results. Also verifies that simple
1233 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001234
Tim Peters4324aa32001-05-28 22:30:08 +00001235C API
1236
1237- Removed the unused last_is_sticky argument from the internal
1238 _PyTuple_Resize(). If this affects you, you were cheating.
1239
1240
Guido van Rossum55a78992001-07-17 17:22:32 +00001241======================================================================
1242
1243
Guido van Rossumffe13be2001-04-16 18:46:45 +00001244What's New in Python 2.1 (final)?
1245=================================
1246
1247We only changed a few things since the last release candidate, all in
1248Python library code:
1249
1250- A bug in the locale module was fixed that affected locales which
1251 define no grouping for numeric formatting.
1252
1253- A few bugs in the weakref module's implementations of weak
1254 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1255 and the test suite was updated to check for these bugs.
1256
1257- An old bug in the os.path.walk() function (introduced in Python
1258 2.0!) was fixed: a non-existent file would cause an exception
1259 instead of being ignored.
1260
1261- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1262 PyChecker.
1263
1264
Guido van Rossum5b08f132001-04-16 02:05:23 +00001265What's New in Python 2.1c2?
1266===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001267
Guido van Rossum5b08f132001-04-16 02:05:23 +00001268A flurry of small changes, and one showstopper fixed in the nick of
1269time made it necessary to release another release candidate. The list
1270here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001271
Guido van Rossum5b08f132001-04-16 02:05:23 +00001272Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001273
Guido van Rossum5b08f132001-04-16 02:05:23 +00001274- Tim discovered a nasty bug in the dictionary code, caused by
1275 PyDict_Next() calling dict_resize(), and the GC code's use of
1276 PyDict_Next() violating an assumption in dict_items(). This was
1277 fixed with considerable amounts of band-aid, but the net effect is a
1278 saner and more robust implementation.
1279
1280- Made a bunch of symbols static that were accidentally global.
1281
1282Build and Ports
1283
1284- The setup.py script didn't check for a new enough version of zlib
1285 (1.1.3 is needed). Now it does.
1286
1287- Changed "make clean" target to also remove shared libraries.
1288
1289- Added a more general warning about the SGI Irix optimizer to README.
1290
1291Library
1292
1293- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1294 omitted the slash between host and file.html.
1295
1296- The mailbox module's _Mailbox class contained a completely broken
1297 and undocumented seek() method. Ripped it out.
1298
1299- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1300 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1301
1302- Fixed a few last-minute bugs in unittest.
1303
1304Extensions
1305
1306- Reverted the patch to the OpenSSL code in socketmodule.c to support
1307 RAND_status() and the EGD, and the subsequent patch that tried to
1308 fix it for pre-0.9.5 versions; the problem with the patch is that on
1309 some systems it issues a warning whenever socket is imported, and
1310 that's unacceptable.
1311
1312Tests
1313
1314- Fixed the pickle tests to work with "import test.test_pickle".
1315
1316- Tweaked test_locale.py to actually run the test Windows.
1317
1318- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1319 not "wb" (which is not a valid mode at all).
1320
1321- Fix pstats browser crashes. Import readline if it exists to make
1322 the user interface nicer.
1323
1324- Add "import thread" to the top of test modules that import the
1325 threading module (test_asynchat and test_threadedtempfile). This
1326 prevents test failures caused by a broken threading module resulting
1327 from a previously caught failed import.
1328
1329- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1330 needed on some platforms (e.g. Solaris 8) when the tests are run
1331 twice in succession.
1332
1333- Skip rather than fail test_sunaudiodev if no audio device is found.
1334
1335
1336What's New in Python 2.1c1?
1337===========================
1338
1339This list was significantly updated when 2.1c2 was released; the 2.1c1
1340release didn't mention most changes that were actually part of 2.1c1:
1341
1342Legal
1343
1344- Copyright was assigned to the Python Software Foundation (PSF) and a
1345 PSF license (very similar to the CNRI license) was added.
1346
1347- The CNRI copyright notice was updated to include 2001.
1348
1349Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001350
Guido van Rossumc9932722001-04-12 02:31:27 +00001351- After a public outcry, assignment to __debug__ is no longer illegal;
1352 instead, a warning is issued. It will become illegal in 2.2.
1353
Guido van Rossum5b08f132001-04-16 02:05:23 +00001354- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1355 "%#x" now always prepends "0x", even if the value is zero.
1356
1357- Fixed some nits in the bytecode compiler.
1358
1359- Fixed core dumps when calling certain kinds of non-functions.
1360
1361- Fixed various core dumps caused by reference count bugs.
1362
1363Build and Ports
1364
1365- Use INSTALL_SCRIPT to install script files.
1366
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001367- New port: SCO Unixware 7, by Billy G. Allie.
1368
Guido van Rossum5b08f132001-04-16 02:05:23 +00001369- Updated RISCOS port.
1370
1371- Updated BeOS port and notes.
1372
1373- Various other porting problems resolved.
1374
1375Library
1376
1377- The TERMIOS and SOCKET modules are now truly obsolete and
1378 unnecessary. Their symbols are incorporated in the termios and
1379 socket modules.
1380
1381- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1382 better tests for pickling.
1383
1384- threading: make Condition.wait() robust against KeyboardInterrupt.
1385
1386- zipfile: add support to zipfile to support opening an archive
1387 represented by an open file rather than a file name. Fix bug where
1388 the archive was not properly closed. Fixed a bug in this bugfix
1389 where flush() was called for a read-only file.
1390
1391- imputil: added an uninstall() method to the ImportManager.
1392
1393- Canvas: fixed bugs in lower() and tkraise() methods.
1394
1395- SocketServer: API change (added overridable close_request() method)
1396 so that the TCP server can explicitly close the request.
1397
1398- pstats: Eric Raymond added a simple interactive statistics browser,
1399 invoked when the module is run as a script.
1400
1401- locale: fixed a problem in format().
1402
1403- webbrowser: made it work when the BROWSER environment variable has a
1404 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1405 KDE 2. Fixed some other nits.
1406
1407- unittest: changes to allow using a different exception than
1408 AssertionError, and added a few more function aliases. Some other
1409 small changes.
1410
1411- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1412
1413- asynchat: fixed a critical bug in asynchat that slipped through the
1414 2.1b2 release. Fixed another rare bug.
1415
1416- Fix some unqualified except: clauses (always a bad code example).
1417
1418XML
1419
1420- pyexpat: new API get_version_string().
1421
1422- Fixed some minidom bugs.
1423
1424Extensions
1425
1426- Fixed a core dump in _weakref. Removed the weakref.mapping()
1427 function (it adds nothing to the API).
1428
1429- Rationalized the use of header files in the readline module, to make
1430 it compile (albeit with some warnings) with the very recent readline
1431 4.2, without breaking for earlier versions.
1432
1433- Hopefully fixed a buffering problem in linuxaudiodev.
1434
1435- Attempted a fix to make the OpenSSL support in the socket module
1436 work again with pre-0.9.5 versions of OpenSSL.
1437
1438Tests
1439
1440- Added a test case for asynchat and asyncore.
1441
1442- Removed coupling between tests where one test failing could break
1443 another.
1444
1445Tools
1446
1447- Ping added an interactive help browser to pydoc, fixed some nits
1448 in the rest of the pydoc code, and added some features to his
1449 inspect module.
1450
1451- An updated python-mode.el version 4.1 which integrates Ken
1452 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1453 much nicer in XEmacs and Emacs. When stepping through your program
1454 with pdb, in either the shell window or the *Python* window, the
1455 source file and line will be tracked by an arrow. Very cool!
1456
1457- IDLE: syntax warnings in interactive mode are changed into errors.
1458
1459- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001460 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001461
1462- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001463
Barry Warsaw11e89c72001-04-11 20:37:57 +00001464
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001465What's New in Python 2.1 beta 2?
1466================================
1467
Guido van Rossum053ae352001-03-22 14:17:21 +00001468(Unlisted are many fixed bugs, more documentation, etc.)
1469
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001470Core language, builtins, and interpreter
1471
Guido van Rossum053ae352001-03-22 14:17:21 +00001472- The nested scopes work (enabled by "from __future__ import
1473 nested_scopes") is completed; in particular, the future now extends
1474 into code executed through exec, eval() and execfile(), and into the
1475 interactive interpreter.
1476
1477- When calling a base class method (e.g. BaseClass.__init__(self)),
1478 this is now allowed even if self is not strictly spoken a class
1479 instance (e.g. when using metaclasses or the Don Beaudry hook).
1480
1481- Slice objects are now comparable but not hashable; this prevents
1482 dict[:] from being accepted but meaningless.
1483
1484- Complex division is now calculated using less braindead algorithms.
1485 This doesn't change semantics except it's more likely to give useful
1486 results in extreme cases. Complex repr() now uses full precision
1487 like float repr().
1488
1489- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1490
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001491- It is illegal to assign to the name __debug__, which is set when the
1492 interpreter starts. It is effectively a compile-time constant.
1493
1494- A warning will be issued if a global statement for a variable
1495 follows a use or assignment of that variable.
1496
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001497Standard library
1498
Guido van Rossum053ae352001-03-22 14:17:21 +00001499- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1500 inspired by JUnit), is now part of the standard library. You now
1501 have a choice of two testing frameworks: unittest requires you to
1502 write testcases as separate code, doctest gathers them from
1503 docstrings. Both approaches have their advantages and
1504 disadvantages.
1505
1506- A new module Tix was added, which wraps the Tix extension library
1507 for Tk. With that module, it is not necessary to statically link
1508 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1509 require" command. See Demo/tix/.
1510
1511- tzparse.py is now obsolete.
1512
1513- In gzip.py, the seek() and tell() methods are removed -- they were
1514 non-functional anyway, and it's better if callers can test for their
1515 existence with hasattr().
1516
1517Python/C API
1518
1519- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1520 that's already in the dictionary during a PyDict_Next() iteration.
1521 This used to fail occasionally when a dictionary resize operation
1522 could be triggered that would rehash all the keys. All other
1523 modifications to the dictionary are still off-limits during a
1524 PyDict_Next() iteration!
1525
1526- New extended APIs related to passing compiler variables around.
1527
1528- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1529 implement isinstance() and issubclass().
1530
1531- Py_BuildValue() now has a "D" conversion to create a Python complex
1532 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001533
Fred Drake4e262a92001-03-22 18:26:47 +00001534- Extensions types which support weak references must now set the
1535 field allocated for the weak reference machinery to NULL themselves;
1536 this is done to avoid the cost of checking each object for having a
1537 weakly referencable type in PyObject_INIT(), since most types are
1538 not weakly referencable.
1539
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001540- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1541 free variables and cell variables to and from the frame's f_locals.
1542
1543- Variants of several functions defined in pythonrun.h have been added
1544 to support the nested_scopes future statement. The variants all end
1545 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1546 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1547 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001548 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001549
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001550Distutils
1551
1552- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1553 into the release tree.
1554
Tim Peters0e57abf2001-05-02 07:39:38 +00001555- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001556 (an uninstaller, more customization of the installer's display)
1557
1558- from Jack Jansen: added Mac-specific code to generate a dialog for
1559 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001560 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001561 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001562
1563- added 'platforms' and 'keywords' to the set of metadata that can be
1564 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001565
1566- applied patches from Jason Tishler to make the compiler class work with
1567 Cygwin.
1568
1569
Tim Peters2fe289a2001-03-01 22:19:38 +00001570What's New in Python 2.1 beta 1?
1571================================
Tim Petersd66595f2001-02-04 03:09:53 +00001572
1573Core language, builtins, and interpreter
1574
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001575- Following an outcry from the community about the amount of code
1576 broken by the nested scopes feature introduced in 2.1a2, we decided
1577 to make this feature optional, and to wait until Python 2.2 (or at
1578 least 6 months) to make it standard. The option can be enabled on a
1579 per-module basis by adding "from __future__ import nested_scopes" at
1580 the beginning of a module (before any other statements, but after
1581 comments and an optional docstring). See PEP 236 (Back to the
1582 __future__) for a description of the __future__ statement. PEP 227
1583 (Statically Nested Scopes) has been updated to reflect this change,
1584 and to clarify the semantics in a number of endcases.
1585
1586- The nested scopes code, when enabled, has been hardened, and most
1587 bugs and memory leaks in it have been fixed.
1588
1589- Compile-time warnings are now generated for a number of conditions
1590 that will break or change in meaning when nested scopes are enabled:
1591
1592 - Using "from...import *" or "exec" without in-clause in a function
1593 scope that also defines a lambda or nested function with one or
1594 more free (non-local) variables. The presence of the import* or
1595 bare exec makes it impossible for the compiler to determine the
1596 exact set of local variables in the outer scope, which makes it
1597 impossible to determine the bindings for free variables in the
1598 inner scope. To avoid the warning about import *, change it into
1599 an import of explicitly name object, or move the import* statement
1600 to the global scope; to avoid the warning about bare exec, use
1601 exec...in... (a good idea anyway -- there's a possibility that
1602 bare exec will be deprecated in the future).
1603
1604 - Use of a global variable in a nested scope with the same name as a
1605 local variable in a surrounding scope. This will change in
1606 meaning with nested scopes: the name in the inner scope will
1607 reference the variable in the outer scope rather than the global
1608 of the same name. To avoid the warning, either rename the outer
1609 variable, or use a global statement in the inner function.
1610
Neil Schemenauera35c6882001-02-27 04:45:05 +00001611- An optional object allocator has been included. This allocator is
1612 optimized for Python objects and should be faster and use less memory
1613 than the standard system allocator. It is not enabled by default
1614 because of possible thread safety problems. The allocator is only
1615 protected by the Python interpreter lock and it is possible that some
1616 extension modules require a thread safe allocator. The object
1617 allocator can be enabled by providing the "--with-pymalloc" option to
1618 configure.
1619
Tim Petersd66595f2001-02-04 03:09:53 +00001620Standard library
1621
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001622- pyexpat now detects the expat version if expat.h defines it. A
1623 number of additional handlers are provided, which are only available
1624 since expat 1.95. In addition, the methods SetParamEntityParsing and
1625 GetInputContext of Parser objects are available with 1.95.x
1626 only. Parser objects now provide the ordered_attributes and
1627 specified_attributes attributes. A new module expat.model was added,
1628 which offers a number of additional constants if 1.95.x is used.
1629
1630- xml.dom offers the new functions registerDOMImplementation and
1631 getDOMImplementation.
1632
1633- xml.dom.minidom offers a toprettyxml method. A number of DOM
1634 conformance issues have been resolved. In particular, Element now
1635 has an hasAttributes method, and the handling of namespaces was
1636 improved.
1637
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001638- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1639 getting information about live Python code, and pydoc.py, a module
1640 for interactively converting docstrings to HTML or text.
1641 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001642 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001643 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1644 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001645
Tim Peters1eff7962001-03-01 02:31:33 +00001646- New library module difflib.py, primarily packaging the SequenceMatcher
1647 class at the heart of the popular ndiff.py file-comparison tool.
1648
1649- doctest.py (a framework for verifying Python code examples in docstrings)
1650 is now part of the std library.
1651
Tim Petersd66595f2001-02-04 03:09:53 +00001652Windows changes
1653
Guido van Rossume3955a82001-03-02 14:05:59 +00001654- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1655 small GUI that lets you browse the module docstrings using your
1656 default web browser.
1657
Tim Peters1eff7962001-03-01 02:31:33 +00001658- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1659 Platforms) is implemented. See
1660
1661 http://python.sourceforge.net/peps/pep-0235.html
1662
1663 for full details, especially the "Current Lower-Left Semantics" section.
1664 The new Windows import rules are simpler than before:
1665
1666 A. If the PYTHONCASEOK environment variable exists, same as
1667 before: silently accept the first case-insensitive match of any
1668 kind; raise ImportError if none found.
1669
1670 B. Else search sys.path for the first case-sensitive match; raise
1671 ImportError if none found.
1672
1673 The same rules have been implented on other platforms with case-
1674 insensitive but case-preserving filesystems too (including Cygwin, and
1675 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001676
Tim Peters25a9ce32001-02-19 07:06:36 +00001677- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1678 what it's supposed to do (and does do under NT and 2000) via direct
1679 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001680 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001681 all Win9x systems before.
1682
Tim Peters1eff7962001-03-01 02:31:33 +00001683- Build: Subproject _test (effectively) renamed to _testcapi.
1684
Tim Peters2fe289a2001-03-01 22:19:38 +00001685New platforms
1686
1687- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1688 Thanks to Steven Majewski!
1689
1690- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1691 Tishler!
1692
Guido van Rossum9089b272001-03-02 06:49:50 +00001693- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1694 Schwertberger! See RISCOS/README for more information -- it seems
1695 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001696 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001697
Tim Peters25a9ce32001-02-19 07:06:36 +00001698
Tim Petersd7b5e882001-01-25 03:36:26 +00001699What's New in Python 2.1 alpha 2?
1700=================================
Tim Peters40ead762001-01-27 05:35:26 +00001701
Tim Petersd7b5e882001-01-25 03:36:26 +00001702Core language, builtins, and interpreter
1703
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001704- Scopes nest. If a name is used in a function or class, but is not
1705 local, the definition in the nearest enclosing function scope will
1706 be used. One consequence of this change is that lambda statements
1707 could reference variables in the namespaces where the lambda is
1708 defined. In some unusual cases, this change will break code.
1709
1710 In all previous version of Python, names were resolved in exactly
1711 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001712 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001713 function A is defined within a function B, the names bound in B are
1714 not visible in A. The new rules make names bound in B visible in A,
1715 unless A contains a name binding that hides the binding in B.
1716
1717 Section 4.1 of the reference manual describes the new scoping rules
1718 in detail. The test script in Lib/test/test_scope.py demonstrates
1719 some of the effects of the change.
1720
1721 The new rules will cause existing code to break if it defines nested
1722 functions where an outer function has local variables with the same
1723 name as globals or builtins used by the inner function. Example:
1724
1725 def munge(str):
1726 def helper(x):
1727 return str(x)
1728 if type(str) != type(''):
1729 str = helper(str)
1730 return str.strip()
1731
1732 Under the old rules, the name str in helper() is bound to the
1733 builtin function str(). Under the new rules, it will be bound to
1734 the argument named str and an error will occur when helper() is
1735 called.
1736
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001737- The compiler will report a SyntaxError if "from ... import *" occurs
1738 in a function or class scope. The language reference has documented
1739 that this case is illegal, but the compiler never checked for it.
1740 The recent introduction of nested scope makes the meaning of this
1741 form of name binding ambiguous. In a future release, the compiler
1742 may allow this form when there is no possibility of ambiguity.
1743
Tim Peters40ead762001-01-27 05:35:26 +00001744- repr(string) is easier to read, now using hex escapes instead of octal,
1745 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1746
1747 >>> "\texample \r\n" + chr(0) + chr(255)
1748 '\texample \r\n\x00\xff' # in 2.1
1749 '\011example \015\012\000\377' # in 2.0
1750
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001751- Functions are now compared and hashed by identity, not by value, since
1752 the func_code attribute is writable.
1753
Fred Drakefb9d7122001-02-01 20:00:40 +00001754- Weak references (PEP 205) have been added. This involves a few
1755 changes in the core, an extension module (_weakref), and a Python
1756 module (weakref). The weakref module is the public interface. It
1757 includes support for "explicit" weak references, proxy objects, and
1758 mappings with weakly held values.
1759
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001760- A 'continue' statement can now appear in a try block within the body
1761 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001762 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001763
Tim Petersd7b5e882001-01-25 03:36:26 +00001764Standard library
1765
Barry Warsaw30dbd142001-01-31 22:14:01 +00001766- mailbox.py now has a new class, PortableUnixMailbox which is
1767 identical to UnixMailbox but uses a more portable scheme for
1768 determining From_ separators. Also, the constructors for all the
1769 classes in this module have a new optional `factory' argument, which
1770 is a callable used when new message classes must be instantiated by
1771 the next() method.
1772
Tim Petersd7b5e882001-01-25 03:36:26 +00001773- random.py is now self-contained, and offers all the functionality of
1774 the now-deprecated whrandom.py. See the docs for details. random.py
1775 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001776 and restoring the internal state of the generator; and jumpahead(n),
1777 for quickly forcing the internal state to be the same as if n calls to
1778 random() had been made. The latter is particularly useful for multi-
1779 threaded programs, creating one instance of the random.Random() class for
1780 each thread, then using .jumpahead() to force each instance to use a
1781 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001782
Tim Peters0de88fc2001-02-01 04:59:18 +00001783- random.py's seed() function is new. For bit-for-bit compatibility with
1784 prior releases, use the whseed function instead. The new seed function
1785 addresses two problems: (1) The old function couldn't produce more than
1786 about 2**24 distinct internal states; the new one about 2**45 (the best
1787 that can be done in the Wichmann-Hill generator). (2) The old function
1788 sometimes produced identical internal states when passed distinct
1789 integers, and there was no simple way to predict when that would happen;
1790 the new one guarantees to produce distinct internal states for all
1791 arguments in [0, 27814431486576L).
1792
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001793- The socket module now supports raw packets on Linux. The socket
1794 family is AF_PACKET.
1795
Tim Peters9ea17ac2001-02-02 05:57:15 +00001796- test_capi.py is a start at running tests of the Python C API. The tests
1797 are implemented by the new Modules/_testmodule.c.
1798
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001799- A new extension module, _symtable, provides provisional access to the
1800 internal symbol table used by the Python compiler. A higher-level
1801 interface will be added on top of _symtable in a future release.
1802
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001803- Removed the obsolete soundex module.
1804
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001805- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1806 the isSameNode method; NamedNodeMap the get method.
1807
1808- xml.sax.expatreader supports the lexical handler property; it
1809 generates comment, startCDATA, and endCDATA events.
1810
Tim Petersee826f82001-01-31 19:39:44 +00001811Windows changes
1812
1813- Build procedure: the zlib project is built in a different way that
1814 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001815 the zlib binary used. See PCbuild\readme.txt for details. Your old
1816 zlib-related directories can be deleted; you'll need to download fresh
1817 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001818
Tim Peters9ea17ac2001-02-02 05:57:15 +00001819- Build: New subproject _test for the benefit of test_capi.py (see above).
1820
Tim Petersb16c56f2001-02-02 21:24:51 +00001821- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1822 interface to some Python compiler internals).
1823
1824- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001825 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001826
Tim Petersa3a3a032000-11-30 05:22:44 +00001827What's New in Python 2.1 alpha 1?
1828=================================
1829
1830Core language, builtins, and interpreter
1831
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001832- There is a new Unicode companion to the PyObject_Str() API
1833 called PyObject_Unicode(). It behaves in the same way as the
1834 former, but assures that the returned value is an Unicode object
1835 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001836
Guido van Rossumf98eda02001-01-17 15:54:45 +00001837- The comparison operators support "rich comparison overloading" (PEP
1838 207). C extension types can provide a rich comparison function in
1839 the new tp_richcompare slot in the type object. The cmp() function
1840 and the C function PyObject_Compare() first try the new rich
1841 comparison operators before trying the old 3-way comparison. There
1842 is also a new C API PyObject_RichCompare() (which also falls back on
1843 the old 3-way comparison, but does not constrain the outcome of the
1844 rich comparison to a Boolean result).
1845
1846 The rich comparison function takes two objects (at least one of
1847 which is guaranteed to have the type that provided the function) and
1848 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1849 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1850 object, which may be NotImplemented (in which case the tp_compare
1851 slot function is used as a fallback, if defined).
1852
1853 Classes can overload individual comparison operators by defining one
1854 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001855 __ge__. There are no explicit "reflected argument" versions of
1856 these; instead, __lt__ and __gt__ are each other's reflection,
1857 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1858 reflection (similar at the C level). No other implications are
1859 made; in particular, Python does not assume that == is the Boolean
1860 inverse of !=, or that < is the Boolean inverse of >=. This makes
1861 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001862
1863 Classes or types that want to implement (in)equality tests but not
1864 the ordering operators (i.e. unordered types) should implement ==
1865 and !=, and raise an error for the ordering operators.
1866
Guido van Rossuma88479f2001-01-18 14:28:08 +00001867 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001868 Boolean; e.g. a matrix type might want to return a matrix of bits
1869 for A < B, giving elementwise comparisons. Such types should ensure
1870 that any interpretation of their value in a Boolean context raises
1871 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1872 at the C level) to always raise an exception.
1873
Guido van Rossuma88479f2001-01-18 14:28:08 +00001874- Complex numbers use rich comparisons to define == and != but raise
1875 an exception for <, <=, > and >=. Unfortunately, this also means
1876 that cmp() of two complex numbers raises an exception when the two
1877 numbers differ. Since it is not mathematically meaningful to compare
1878 complex numbers except for equality, I hope that this doesn't break
1879 too much code.
1880
Tim Peters3389f192001-02-18 08:48:49 +00001881- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001882 not defined by the language, other than that it's arbitrary but
1883 consistent (see the Reference Manual). An implementation detail changed
1884 in 2.1a1 such that None now compares less than any other object. Code
1885 relying on this new behavior (like code that relied on the previous
1886 behavior) does so at its own risk.
1887
Barry Warsaw573b5412001-01-15 20:43:18 +00001888- Functions and methods now support getting and setting arbitrarily
1889 named attributes (PEP 232). Functions have a new __dict__
1890 (a.k.a. func_dict) which hold the function attributes. Methods get
1891 and set attributes on their underlying im_func. It is a TypeError
1892 to set an attribute on a bound method.
1893
Guido van Rossum051e3352001-01-15 19:11:10 +00001894- The xrange() object implementation has been improved so that
1895 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1896 limitation that in this case len(xrange(sys.maxint)) can't be
1897 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1898 work fine as long as the index i doesn't actually reach 2**31.
1899 (Python uses regular ints for sequence and string indices; fixing
1900 that is much more work.)
1901
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001902- Two changes to from...import:
1903
Guido van Rossumba381232001-02-03 15:06:40 +00001904 1) "from M import X" now works even if (after loading module M)
1905 sys.modules['M'] is not a real module; it's basically a getattr()
1906 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001907
1908 2) "from M import *" now looks for M.__all__ to decide which names to
1909 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1910 filters out names starting with '_' as before. Whether or not
1911 __all__ exists, there's no restriction on the type of M.
1912
Guido van Rossumf61f1662001-01-10 20:13:55 +00001913- File objects have a new method, xreadlines(). This is the fastest
1914 way to iterate over all lines in a file:
1915
1916 for line in file.xreadlines():
1917 ...do something to line...
1918
1919 See the xreadlines module (mentioned below) for how to do this for
1920 other file-like objects.
1921
1922- Even if you don't use file.xreadlines(), you may expect a speedup on
1923 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001924 quite a bit in platform-specific ways: on systems (like Linux) that
1925 support flockfile(), getc_unlocked(), and funlockfile(), those are
1926 used by default. On systems (like Windows) without getc_unlocked(),
1927 a complicated (but still thread-safe) method using fgets() is used by
1928 default.
1929
Tim Petersd52269b2001-01-25 06:23:18 +00001930 You can force use of the fgets() method by #define'ing
1931 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001932 getc_unlocked()).
1933
Tim Petersd52269b2001-01-25 06:23:18 +00001934 You can force fgets() not to be used by #define'ing
1935 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001936 test_bufio.py fails -- and let us know if it does!).
1937
1938- In addition, the fileinput module, while still slower than the other
1939 methods on most platforms, has been sped up too, by using
1940 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001941
1942- Support for run-time warnings has been added, including a new
1943 command line option (-W) to specify the disposition of warnings.
1944 See the description of the warnings module below.
1945
1946- Extensive changes have been made to the coercion code. This mostly
1947 affects extension modules (which can now implement mixed-type
1948 numerical operators without having to use coercion), but
1949 occasionally, in boundary cases the coercion semantics have changed
1950 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001951 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001952 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001953 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001954
Guido van Rossumf98eda02001-01-17 15:54:45 +00001955- In connection with the coercion changes, a new built-in singleton
1956 object, NotImplemented is defined. This can be returned for
1957 operations that wish to indicate they are not implemented for a
1958 particular combination of arguments. From C, this is
1959 Py_NotImplemented.
1960
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001961- The interpreter accepts now bytecode files on the command line even
1962 if they do not have a .pyc or .pyo extension. On Linux, after executing
1963
Martin v. Löwise214baa2001-02-04 22:37:56 +00001964import imp,sys,string
1965magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1966reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1967open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001968
1969 any byte code file can be used as an executable (i.e. as an argument
1970 to execve(2)).
1971
Tim Peters9940b802000-12-01 07:59:35 +00001972- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001973 character. In 1.6 and earlier, they never produced a sign,
1974 and raised an error if the value of the long was too large
1975 to fit in a Python int. In 2.0, they produced a sign if and
1976 only if too large to fit in an int. This was inconsistent
1977 across platforms (because the size of an int varies across
1978 platforms), and inconsistent with hex() and oct(). Example:
1979
1980 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001981 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001982 'ffffffbe' # in 2.0 and before, on 32-bit machines
1983 >>> hex(-0x42L)
1984 '-0x42L' # in all versions of Python
1985
Tim Peters9940b802000-12-01 07:59:35 +00001986 The behavior of %d formats for negative Python longs remains
1987 the same as in 2.0 (although in 1.6 and before, they raised
1988 an error if the long didn't fit in a Python int).
1989
1990 %u formats don't make sense for Python longs, but are allowed
1991 and treated the same as %d in 2.1. In 2.0, a negative long
1992 formatted via %u produced a sign if and only if too large to
1993 fit in an int. In 1.6 and earlier, a negative long formatted
1994 via %u raised an error if it was too big to fit in an int.
1995
Guido van Rossum3661d392000-12-12 22:10:31 +00001996- Dictionary objects have an odd new method, popitem(). This removes
1997 an arbitrary item from the dictionary and returns it (in the form of
1998 a (key, value) pair). This can be useful for algorithms that use a
1999 dictionary as a bag of "to do" items and repeatedly need to pick one
2000 item. Such algorithms normally end up running in quadratic time;
2001 using popitem() they can usually be made to run in linear time.
2002
Tim Peters36cdad12000-12-29 02:06:45 +00002003Standard library
2004
Thomas Woutersfe385252001-01-19 23:16:56 +00002005- In the time module, the time argument to the functions strftime,
2006 localtime, gmtime, asctime and ctime is now optional, defaulting to
2007 the current time (in the local timezone).
2008
Guido van Rossumda91f222001-01-15 16:36:08 +00002009- The ftplib module now defaults to passive mode, which is deemed a
2010 more useful default given that clients are often inside firewalls
2011 these days. Note that this could break if ftplib is used to connect
2012 to a *server* that is inside a firewall, from outside; this is
2013 expected to be a very rare situation. To fix that, you can call
2014 ftp.set_pasv(0).
2015
Martin v. Löwis10a27872001-01-13 09:54:41 +00002016- The module site now treats .pth files not only for path configuration,
2017 but also supports extensions to the initialization code: Lines starting
2018 with import are executed.
2019
Guido van Rossumf61f1662001-01-10 20:13:55 +00002020- There's a new module, warnings, which implements a mechanism for
2021 issuing and filtering warnings. There are some new built-in
2022 exceptions that serve as warning categories, and a new command line
2023 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2024 turns warnings into errors). warnings.warn(message[, category])
2025 issues a warning message; this can also be called from C as
2026 PyErr_Warn(category, message).
2027
2028- A new module xreadlines was added. This exports a single factory
2029 function, xreadlines(). The intention is that this code is the
2030 absolutely fastest way to iterate over all lines in an open
2031 file(-like) object:
2032
2033 import xreadlines
2034 for line in xreadlines.xreadlines(file):
2035 ...do something to line...
2036
2037 This is equivalent to the previous the speed record holder using
2038 file.readlines(sizehint). Note that if file is a real file object
2039 (as opposed to a file-like object), this is equivalent:
2040
2041 for line in file.xreadlines():
2042 ...do something to line...
2043
Tim Peters36cdad12000-12-29 02:06:45 +00002044- The bisect module has new functions bisect_left, insort_left,
2045 bisect_right and insort_right. The old names bisect and insort
2046 are now aliases for bisect_right and insort_right. XXX_right
2047 and XXX_left methods differ in what happens when the new element
2048 compares equal to one or more elements already in the list: the
2049 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002050 right. Code that doesn't care where equal elements end up should
2051 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002052
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002053- The new curses.panel module wraps the panel library that forms part
2054 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2055
Guido van Rossumf61f1662001-01-10 20:13:55 +00002056- The SocketServer module now sets the allow_reuse_address flag by
2057 default in the TCPServer class.
2058
2059- A new function, sys._getframe(), returns the stack frame pointer of
2060 the caller. This is intended only as a building block for
2061 higher-level mechanisms such as string interpolation.
2062
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002063- The pyexpat module supports a number of new handlers, which are
2064 available only in expat 1.2. If invocation of a callback fails, it
2065 will report an additional frame in the traceback. Parser objects
2066 participate now in garbage collection. If expat reports an unknown
2067 encoding, pyexpat will try to use a Python codec; that works only
2068 for single-byte charsets. The parser type objects is exposed as
2069 XMLParserObject.
2070
2071- xml.dom now offers standard definitions for symbolic node type and
2072 exception code constants, and a hierarchy of DOM exceptions. minidom
2073 was adjusted to use them.
2074
2075- The conformance of xml.dom.minidom to the DOM specification was
2076 improved. It detects a number of additional error cases; the
2077 previous/next relationship works even when the tree is modified;
2078 Node supports the normalize() method; NamedNodeMap, DocumentType and
2079 DOMImplementation classes were added; Element supports the
2080 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2081 method.
2082
Guido van Rossumf61f1662001-01-10 20:13:55 +00002083Build issues
2084
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002085- For Unix (and Unix-compatible) builds, configuration and building of
2086 extension modules is now greatly automated. Rather than having to
2087 edit the Modules/Setup file to indicate which modules should be
2088 built and where their include files and libraries are, a
2089 distutils-based setup.py script now takes care of building most
2090 extension modules. All extension modules built this way are built
2091 as shared libraries. Only a few modules that must be linked
2092 statically are still listed in the Setup file; you won't need to
2093 edit their configuration.
2094
2095- Python should now build out of the box on Cygwin. If it doesn't,
2096 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002097
2098- Python now always uses its own (renamed) implementation of getopt()
2099 -- there's too much variation among C library getopt()
2100 implementations.
2101
2102- C++ compilers are better supported; the CXX macro is always set to a
2103 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002104
Tim Petersd92dfe02000-12-12 01:18:41 +00002105Windows changes
2106
2107- select module: By default under Windows, a select() call
2108 can specify no more than 64 sockets. Python now boosts
2109 this Microsoft default to 512. If you need even more than
2110 that, see the MS docs (you'll need to #define FD_SETSIZE
2111 and recompile Python from source).
2112
Guido van Rossumf61f1662001-01-10 20:13:55 +00002113- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2114 subdirectory is no more!
2115
Tim Petersa3a3a032000-11-30 05:22:44 +00002116
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002117What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002118=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002119
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002120Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002121changes are in the file HISTORY. If you are making the jump directly
2122from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2123HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002124
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002125Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2126the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2127http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002128
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002129--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002130
2131======================================================================
2132
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002133What's new in 2.0 (since release candidate 1)?
2134==============================================
2135
2136Standard library
2137
2138- The copy_reg module was modified to clarify its intended use: to
2139 register pickle support for extension types, not for classes.
2140 pickle() will raise a TypeError if it is passed a class.
2141
2142- Fixed a bug in gettext's "normalize and expand" code that prevented
2143 it from finding an existing .mo file.
2144
2145- Restored support for HTTP/0.9 servers in httplib.
2146
Tim Peters989b7b92000-10-16 20:24:53 +00002147- The math module was changed to stop raising OverflowError in case of
2148 underflow, and return 0 instead in underflow cases. Whether Python
2149 used to raise OverflowError in case of underflow was platform-
2150 dependent (it did when the platform math library set errno to ERANGE
2151 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002152
2153- Fixed a bug in StringIO that occurred when the file position was not
2154 at the end of the file and write() was called with enough data to
2155 extend past the end of the file.
2156
2157- Fixed a bug that caused Tkinter error messages to get lost on
2158 Windows. The bug was fixed by replacing direct use of
2159 interp->result with Tcl_GetStringResult(interp).
2160
2161- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2162 redirect response.
2163
2164- Several changes were made to distutils: Some debugging code was
2165 removed from util. Fixed the installer used when an external zip
2166 program (like WinZip) is not found; the source code for this
2167 installer is in Misc/distutils. check_lib() was modified to behave
2168 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2169 test for whether installed modules are on sys.path was changed to
2170 use both normcase() and normpath().
2171
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002172- Several minor bugs were fixed in the xml package (the minidom,
2173 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002174
2175- The regression test driver (regrtest.py) behavior when invoked with
2176 -l changed: It now reports a count of objects that are recognized as
2177 garbage but not freed by the garbage collector.
2178
Tim Peters989b7b92000-10-16 20:24:53 +00002179- The regression test for the math module was changed to test
2180 exceptional behavior when the test is run in verbose mode. Python
2181 cannot yet guarantee consistent exception behavior across platforms,
2182 so the exception part of test_math is run only in verbose mode, and
2183 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002184
2185Internals
2186
2187- PyOS_CheckStack() has been disabled on Win64, where it caused
2188 test_sre to fail.
2189
2190Build issues
2191
2192- Changed compiler flags, so that gcc is always invoked with -Wall and
2193 -Wstrict-prototypes. Users compiling Python with GCC should see
2194 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002195 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002196 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002197
Tim Petersa3a3a032000-11-30 05:22:44 +00002198- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002199
2200Tools and other miscellany
2201
2202- The compiler in Tools/compiler was updated to support the new
2203 language features introduced in 2.0: extended print statement, list
2204 comprehensions, and augmented assignments. The new compiler should
2205 also be backwards compatible with Python 1.5.2; the compiler will
2206 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002207 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002208
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002209What's new in 2.0 release candidate 1 (since beta 2)?
2210=====================================================
2211
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002212What is release candidate 1?
2213
2214We believe that release candidate 1 will fix all known bugs that we
2215intend to fix for the 2.0 final release. This release should be a bit
2216more stable than the previous betas. We would like to see even more
2217widespread testing before the final release, so we are producing this
2218release candidate. The final release will be exactly the same unless
2219any show-stopping (or brown bag) bugs are found by testers of the
2220release candidate.
2221
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002222All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002223to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002224
2225Core language, builtins, and interpreter
2226
2227- A bug that caused crashes when __coerce__ was used with augmented
2228 assignment, e.g. +=, was fixed.
2229
2230- Raise ZeroDivisionError when raising zero to a negative number,
2231 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2232 power operator and the result of math.pow(0.0, -2.0) will vary by
2233 platform. On Linux, it raises a ValueError.
2234
2235- A bug in Unicode string interpolation was fixed that occasionally
2236 caused errors with formats including "%%". For example, the
2237 following expression "%% %s" % u"abc" no longer raises a TypeError.
2238
2239- Compilation of deeply nested expressions raises MemoryError instead
2240 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2241
2242- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2243 rendering them useless. They are now written in binary mode again.
2244
2245Standard library
2246
2247- Keyword arguments are now accepted for most pattern and match object
2248 methods in SRE, the standard regular expression engine.
2249
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002250- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002251 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002252
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002253- Several bugs in the Unicode handling and error handling in _tkinter
2254 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002255
2256- Fix memory management errors in Merge() and Tkapp_Call() routines.
2257
2258- Several changes were made to cStringIO to make it compatible with
2259 the file-like object interface and with StringIO. If operations are
2260 performed on a closed object, an exception is raised. The truncate
2261 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002262 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002263
2264- There were many changes made to the linuxaudiodev module and its
2265 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002266 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002267
2268 Note that this module is named poorly, because it should work
2269 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002270 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002271
2272 The module now raises exceptions when errors occur instead of
2273 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2274 audio) and defines a getptr() method that calls the
2275 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2276
2277- The library_version attribute, introduced in an earlier beta, was
2278 removed because it can not be supported with early versions of the C
2279 readline library, which provides no way to determine the version at
2280 compile-time.
2281
2282- The binascii module is now enabled on Win64.
2283
Tim Peters46446d62000-10-09 21:19:31 +00002284- tokenize.py no longer suffers "recursion depth" errors when parsing
2285 programs with very long string literals.
2286
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002287Internals
2288
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002289- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002290 which is called when the interpreter starts up to determine where
2291 the standard library is installed. These vulnerabilities affect all
2292 previous versions of Python and can be exploited by setting very
2293 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2294 setuid Python script, although use of the wrapper in
2295 Misc/setuid-prog.c will eliminate the vulnerability.
2296
2297- Fixed garbage collection bugs in instance creation that were
2298 triggered when errors occurred during initialization. The solution,
2299 applied in cPickle and in PyInstance_New(), is to call
2300 PyObject_GC_Init() after the initialization of the object's
2301 container attributes is complete.
2302
2303- pyexpat adds definitions of PyModule_AddStringConstant and
2304 PyModule_AddObject if the Python version is less than 2.0, which
2305 provides compatibility with PyXML on Python 1.5.2.
2306
2307- If the platform has a bogus definition for LONG_BIT (the number of
2308 bits in a long), an error will be reported at compile time.
2309
2310- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2311 collection crashes and possibly other, unreported crashes.
2312
2313- Fixed a memory leak in _PyUnicode_Fini().
2314
2315Build issues
2316
2317- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002318 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002319 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002320
2321- The mmap.PAGESIZE constant is now initialized using sysconf when
2322 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2323
2324- The md5 file should now compile on all platforms.
2325
2326- The select module now compiles on platforms that do not define
2327 POLLRDNORM and related constants.
2328
2329- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002330 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002331
Jeremy Hylton10921202000-10-09 18:34:12 +00002332- BeOS: A number of changes were made to the build and installation
2333 process. ar-fake now operates on a directory of object files.
2334 dl_export.h is gone, and its macros now appear on the mwcc command
2335 line during build on PPC BeOS.
2336
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002337- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002338 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002339
2340- Cygwin: Support for shared libraries, Tkinter, and sockets.
2341
2342- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2343
2344Tools and other miscellany
2345
2346- Removed debugging prints from main used with freeze.
2347
Tim Peters46446d62000-10-09 21:19:31 +00002348- IDLE auto-indent no longer crashes when it encounters Unicode
2349 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002350
2351What's new in 2.0 beta 2 (since beta 1)?
2352========================================
2353
2354Core language, builtins, and interpreter
2355
Tim Peters482c0212000-09-26 06:33:09 +00002356- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002357 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002358
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002359- Add -h and -V command line options to print the usage message and
2360 Python version number and exit immediately.
2361
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002362- eval() and exec accept Unicode objects as code parameters.
2363
2364- getattr() and setattr() now also accept Unicode objects for the
2365 attribute name, which are converted to strings using the default
2366 encoding before lookup.
2367
2368- Multiplication on string and Unicode now does proper bounds
2369 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2370 string is too long."
2371
2372- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002373 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002374
Jeremy Hylton1b618592000-09-26 05:32:36 +00002375
2376Standard library and extensions
2377
Guido van Rossum5b08f132001-04-16 02:05:23 +00002378- socket module: the OpenSSL code now adds support for RAND_status()
2379 and EGD (Entropy Gathering Device).
2380
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002381- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002382 argument checking; it still takes no arguments.
2383
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002384- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002385
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002386- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002387
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002388- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002389
2390- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002391 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002392
2393- copy: Copy Unicode objects atomically.
2394
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002395- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002396
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002397- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002398
Fred Drake67233bc2000-09-26 16:40:27 +00002399- dbm: Add get() and setdefault() methods to dbm object. Add constant
2400 `library' to module that names the library used. Added doc strings
2401 and method names to error messages. Uses configure to determine
2402 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2403 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002404
2405- distutils: Update to version 0.9.3.
2406
2407- dl: Add several dl.RTLD_ constants.
2408
2409- fpectl: Now supported on FreeBSD.
2410
2411- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2412 found by the collector will be saved in gc.garbage. This is useful
2413 for debugging a program that creates reference cycles.
2414
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002415- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002416 of HTTP class. Do not close socket on zero-length response. Do not
2417 crash when server sends invalid content-length header.
2418
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002419- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002420
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002421- marshal: When reading a short, sign-extend on platforms where shorts
2422 are bigger than 16 bits. When reading a long, repair the unportable
2423 sign extension that was being done for 64-bit machines. (It assumed
2424 that signed right shift sign-extends.)
2425
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002426- operator: Add contains(), invert(), __invert__() as aliases for
2427 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002428
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002429- os: Add support for popen2() and popen3() on all platforms where
2430 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002431
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002432- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002433 clicking on a file in Explorer (or passing the file name to the
2434 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002435
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002436- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002437 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002438
2439- pickle: Now raises ValueError when an invalid pickle that contains
2440 a non-string repr where a string repr was expected. This behavior
2441 matches cPickle.
2442
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002443- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002444
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002445- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002446
2447- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002448 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002449 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002450
2451- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002452 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002453
2454- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002455 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002456 few cycles during startup since the first call to
2457 setdefaultencoding() will initialize the codec registry and the
2458 encodings package.
2459
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002460- socket: Support for size hint in readlines() method of object returned
2461 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002462
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002463- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002464 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002465 is followed by whitespace.
2466
Tim Petersa3a3a032000-11-30 05:22:44 +00002467- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002468
2469- struct: Check ranges for bytes and shorts.
2470
2471- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002472 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002473
2474- Tkinter: Image objects are now guaranteed to have unique ids. Set
2475 event.delta to zero if Tk version doesn't support mousewheel.
2476 Removed some debugging prints.
2477
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002478- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002479
Fred Drake67233bc2000-09-26 16:40:27 +00002480- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002481 which works around a bug in Norton AntiVirus 2000 that leads directly
2482 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002483
2484- xml: New version detection code allows PyXML to override standard
2485 XML package if PyXML version is greater than 0.6.1.
2486
Fred Drake64bb3802000-09-26 16:21:35 +00002487- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2488 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2489 tree only for nodes which are sufficiently interesting to a specific
2490 application. Does not provide the HTML-specific extensions. Still
2491 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002492
Fred Drake64bb3802000-09-26 16:21:35 +00002493- xml.sax: SAX 2 support for Python, including all the handler
2494 interfaces needed to process XML 1.0 compliant XML. Some
2495 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002496
Fred Drake64bb3802000-09-26 16:21:35 +00002497- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2498 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002499
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002500
Jeremy Hylton1b618592000-09-26 05:32:36 +00002501C API
2502
2503- Add three new convenience functions for module initialization --
2504 PyModule_AddObject(), PyModule_AddIntConstant(), and
2505 PyModule_AddStringConstant().
2506
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002507- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002508 removed and add #error to Python.h if NULL isn't defined after
2509 #include of stdio.h.
2510
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002511- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002512 backwards compatibility (at the source level) with old extensions.
2513
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002514- A wrapper API was added for signal() and sigaction(). Instead of
2515 either function, always use PyOS_getsig() to get a signal handler
2516 and PyOS_setsig() to set one. A new convenience typedef
2517 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002518
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002519- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002520 internal data buffer and size of a string object -- or the default
2521 encoded version of a Unicode object.
2522
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002523- PyString_Size() and PyString_AsString() accept Unicode objects.
2524
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002525- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002526 exists). INT_MAX and LONG_MAX will always be defined, even if
2527 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002528
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002529- PyFloat_FromString takes a second argument, pend, that was
2530 effectively useless. It is now officially useless but preserved for
2531 backwards compatibility. If the pend argument is not NULL, *pend is
2532 set to NULL.
2533
2534- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2535 for the attribute name. See note on getattr() above.
2536
2537- A few bug fixes to argument processing for Unicode.
2538 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2539 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2540 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002541 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002542
2543- Py_BuildValue accepts B format (for bgen-generated code).
2544
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002545
Jeremy Hylton1b618592000-09-26 05:32:36 +00002546Internals
2547
2548- On Unix, fix code for finding Python installation directory so that
2549 it works when argv[0] is a relative path.
2550
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002551- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002552 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002553 rather than by generating a copy of the object.
2554
Tim Peters482c0212000-09-26 06:33:09 +00002555- Several of the internal Unicode tables are much smaller now, and
2556 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002557
Jeremy Hylton97693b02000-09-26 17:42:51 +00002558- In the garbage collector: Fixed bug in collection of tuples. Fixed
2559 bug that caused some instances to be removed from the container set
2560 while they were still live. Fixed parsing in gc.set_debug() for
2561 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002562
2563- Fixed refcount problem in instance deallocation that only occurred
2564 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2565
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002566- On Windows, getpythonregpath is now protected against null data in
2567 registry key.
2568
2569- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002570 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002571
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002572
Jeremy Hylton1b618592000-09-26 05:32:36 +00002573Build and platform-specific issues
2574
2575- Better support of GNU Pth via --with-pth configure option.
2576
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002577- Python/C API now properly exposed to dynamically-loaded extension
2578 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002579
2580- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2581 Don't define MS_SYNC to be zero when it is undefined. Added missing
2582 prototypes in posixmodule.c.
2583
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002584- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002585 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002586
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002587- Fix largefile support on older NetBSD systems and OpenBSD by adding
2588 define for TELL64.
2589
2590
2591Tools and other miscellany
2592
2593- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2594
2595- freeze: The modulefinder now works with 2.0 opcodes.
2596
Tim Petersa3a3a032000-11-30 05:22:44 +00002597- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002598 Move hackery of sys.argv until after the Tk instance has been
2599 created, which allows the application-specific Tkinter
2600 initialization to be executed if present; also pass an explicit
2601 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002602
Jeremy Hylton1b618592000-09-26 05:32:36 +00002603
2604What's new in 2.0 beta 1?
2605=========================
2606
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002607Source Incompatibilities
2608------------------------
2609
2610None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2611such as single-argument append(), connect() and bind(), and changes to
2612str(long) and repr(float).
2613
2614
2615Binary Incompatibilities
2616------------------------
2617
2618- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2619with Python 2.0; these extensions will have to be rebuilt for Python
26202.0.
2621
2622- On Windows, attempting to import a third party extension built for
2623Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2624can do about this. Check your PYTHONPATH environment variable!
2625
2626- Python bytecode files (*.pyc and *.pyo) are not compatible between
2627releases.
2628
2629
2630Overview of Changes Since 1.6
2631-----------------------------
2632
2633There are many new modules (including brand new XML support through
2634the xml package, and i18n support through the gettext module); a list
2635of all new modules is included below. Lots of bugs have been fixed.
2636
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002637The process for making major new changes to the language has changed
2638since Python 1.6. Enhancements must now be documented by a Python
2639Enhancement Proposal (PEP) before they can be accepted.
2640
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002641There are several important syntax enhancements, described in more
2642detail below:
2643
2644 - Augmented assignment, e.g. x += 1
2645
2646 - List comprehensions, e.g. [x**2 for x in range(10)]
2647
2648 - Extended import statement, e.g. import Module as Name
2649
2650 - Extended print statement, e.g. print >> file, "Hello"
2651
2652Other important changes:
2653
2654 - Optional collection of cyclical garbage
2655
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002656Python Enhancement Proposal (PEP)
2657---------------------------------
2658
2659PEP stands for Python Enhancement Proposal. A PEP is a design
2660document providing information to the Python community, or describing
2661a new feature for Python. The PEP should provide a concise technical
2662specification of the feature and a rationale for the feature.
2663
2664We intend PEPs to be the primary mechanisms for proposing new
2665features, for collecting community input on an issue, and for
2666documenting the design decisions that have gone into Python. The PEP
2667author is responsible for building consensus within the community and
2668documenting dissenting opinions.
2669
2670The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002671
2672Augmented Assignment
2673--------------------
2674
2675This must have been the most-requested feature of the past years!
2676Eleven new assignment operators were added:
2677
Guido van Rossume905e952000-09-05 12:42:46 +00002678 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002679
2680For example,
2681
2682 A += B
2683
2684is similar to
2685
2686 A = A + B
2687
2688except that A is evaluated only once (relevant when A is something
2689like dict[index].attr).
2690
2691However, if A is a mutable object, A may be modified in place. Thus,
2692if A is a number or a string, A += B has the same effect as A = A+B
2693(except A is only evaluated once); but if a is a list, A += B has the
2694same effect as A.extend(B)!
2695
2696Classes and built-in object types can override the new operators in
2697order to implement the in-place behavior; the not-in-place behavior is
2698used automatically as a fallback when an object doesn't implement the
2699in-place behavior. For classes, the method name is derived from the
2700method name for the corresponding not-in-place operator by inserting
2701an 'i' in front of the name, e.g. __iadd__ implements in-place
2702__add__.
2703
2704Augmented assignment was implemented by Thomas Wouters.
2705
2706
2707List Comprehensions
2708-------------------
2709
2710This is a flexible new notation for lists whose elements are computed
2711from another list (or lists). The simplest form is:
2712
2713 [<expression> for <variable> in <sequence>]
2714
Guido van Rossum56db0952000-09-06 23:34:25 +00002715For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002716This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002717
2718You can also add a condition:
2719
2720 [<expression> for <variable> in <sequence> if <condition>]
2721
2722For example, [w for w in words if w == w.lower()] would yield the list
2723of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002724than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002725
2726You can also have nested for loops and more than one 'if' clause. For
2727example, here's a function that flattens a sequence of sequences::
2728
2729 def flatten(seq):
2730 return [x for subseq in seq for x in subseq]
2731
2732 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2733
2734This prints
2735
2736 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2737
2738List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002739Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002740
2741
2742Extended Import Statement
2743-------------------------
2744
2745Many people have asked for a way to import a module under a different
2746name. This can be accomplished like this:
2747
2748 import foo
2749 bar = foo
2750 del foo
2751
2752but this common idiom gets old quickly. A simple extension of the
2753import statement now allows this to be written as follows:
2754
2755 import foo as bar
2756
2757There's also a variant for 'from ... import':
2758
2759 from foo import bar as spam
2760
2761This also works with packages; e.g. you can write this:
2762
2763 import test.regrtest as regrtest
2764
2765Note that 'as' is not a new keyword -- it is recognized only in this
2766context (this is only possible because the syntax for the import
2767statement doesn't involve expressions).
2768
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002769Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002770
2771
2772Extended Print Statement
2773------------------------
2774
2775Easily the most controversial new feature, this extension to the print
2776statement adds an option to make the output go to a different file
2777than the default sys.stdout.
2778
2779For example, to write an error message to sys.stderr, you can now
2780write:
2781
2782 print >> sys.stderr, "Error: bad dog!"
2783
2784As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002785evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002786
2787 print >> None, "Hello world"
2788
2789is equivalent to
2790
2791 print "Hello world"
2792
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002793Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002794
2795
2796Optional Collection of Cyclical Garbage
2797---------------------------------------
2798
2799Python is now equipped with a garbage collector that can hunt down
2800cyclical references between Python objects. It's no replacement for
2801reference counting; in fact, it depends on the reference counts being
2802correct, and decides that a set of objects belong to a cycle if all
2803their reference counts can be accounted for from their references to
2804each other. This devious scheme was first proposed by Eric Tiedemann,
2805and brought to implementation by Neil Schemenauer.
2806
2807There's a module "gc" that lets you control some parameters of the
2808garbage collection. There's also an option to the configure script
2809that lets you enable or disable the garbage collection. In 2.0b1,
2810it's on by default, so that we (hopefully) can collect decent user
2811experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002812performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002813off by default in the final 2.0 release.
2814
2815
2816Smaller Changes
2817---------------
2818
2819A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2820map(None, seq1, seq2, ...) when the sequences have the same length;
2821i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2822the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002823zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002824
2825sys.version_info is a tuple (major, minor, micro, level, serial).
2826
2827Dictionaries have an odd new method, setdefault(key, default).
2828dict.setdefault(key, default) returns dict[key] if it exists; if not,
2829it sets dict[key] to default and returns that value. Thus:
2830
2831 dict.setdefault(key, []).append(item)
2832
2833does the same work as this common idiom:
2834
2835 if not dict.has_key(key):
2836 dict[key] = []
2837 dict[key].append(item)
2838
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002839There are two new variants of SyntaxError that are raised for
2840indentation-related errors: IndentationError and TabError.
2841
2842Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2843escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002844
2845The limits on the size of expressions and file in Python source code
2846have been raised from 2**16 to 2**32. Previous versions of Python
2847were limited because the maximum argument size the Python VM accepted
2848was 2**16. This limited the size of object constructor expressions,
2849e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2850limit was raised thanks to a patch by Charles Waldman that effectively
2851fixes the problem. It is now much more likely that you will be
2852limited by available memory than by an arbitrary limit in Python.
2853
2854The interpreter's maximum recursion depth can be modified by Python
2855programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2856limit is the maximum number of recursive calls that can be made by
2857Python code. The limit exists to prevent infinite recursion from
2858overflowing the C stack and causing a core dump. The default value is
28591000. The maximum safe value for a particular platform can be found
2860by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002861
2862New Modules and Packages
2863------------------------
2864
2865atexit - for registering functions to be called when Python exits.
2866
2867imputil - Greg Stein's alternative API for writing custom import
2868hooks.
2869
2870pyexpat - an interface to the Expat XML parser, contributed by Paul
2871Prescod.
2872
2873xml - a new package with XML support code organized (so far) in three
2874subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2875would fill a volume. There's a special feature whereby a
2876user-installed package named _xmlplus overrides the standard
2877xmlpackage; this is intended to give the XML SIG a hook to distribute
2878backwards-compatible updates to the standard xml package.
2879
2880webbrowser - a platform-independent API to launch a web browser.
2881
2882
Guido van Rossume905e952000-09-05 12:42:46 +00002883Changed Modules
2884---------------
2885
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002886array -- new methods for array objects: count, extend, index, pop, and
2887remove
2888
2889binascii -- new functions b2a_hex and a2b_hex that convert between
2890binary data and its hex representation
2891
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002892calendar -- Many new functions that support features including control
2893over which day of the week is the first day, returning strings instead
2894of printing them. Also new symbolic constants for days of week,
2895e.g. MONDAY, ..., SUNDAY.
2896
2897cgi -- FieldStorage objects have a getvalue method that works like a
2898dictionary's get method and returns the value attribute of the object.
2899
2900ConfigParser -- The parser object has new methods has_option,
2901remove_section, remove_option, set, and write. They allow the module
2902to be used for writing config files as well as reading them.
2903
2904ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002905optionally support the RFC 959 REST command.
2906
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002907gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002908
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002909httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2910the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002911
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002912locale -- implement getdefaultlocale for Win32 and Macintosh
2913
2914marshal -- no longer dumps core when marshaling deeply nested or
2915recursive data structures
2916
2917os -- new functions isatty, seteuid, setegid, setreuid, setregid
2918
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002919os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2920support under Unix.
2921
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002922os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002923
2924os.path -- fix semantics of os.path.commonprefix
2925
2926smtplib -- support for sending very long messages
2927
2928socket -- new function getfqdn()
2929
2930readline -- new functions to read, write and truncate history files.
2931The readline section of the library reference manual contains an
2932example.
2933
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002934select -- add interface to poll system call
2935
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002936shutil -- new copyfileobj function
2937
2938SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2939HTTP server.
2940
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002941Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002942
2943urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002944e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002945
2946whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002947
2948
2949Obsolete Modules
2950----------------
2951
2952None. However note that 1.6 made a whole slew of modules obsolete:
2953stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2954poly, zmod, strop, util, whatsound.
2955
2956
2957Changed, New, Obsolete Tools
2958----------------------------
2959
Tim Peters8b092332000-09-05 20:15:25 +00002960None.
Guido van Rossume905e952000-09-05 12:42:46 +00002961
2962
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002963C-level Changes
2964---------------
2965
2966Several cleanup jobs were carried out throughout the source code.
2967
2968All C code was converted to ANSI C; we got rid of all uses of the
2969Py_PROTO() macro, which makes the header files a lot more readable.
2970
2971Most of the portability hacks were moved to a new header file,
2972pyport.h; several other new header files were added and some old
2973header files were removed, in an attempt to create a more rational set
2974of header files. (Few of these ever need to be included explicitly;
2975they are all included by Python.h.)
2976
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002977Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002978and Win64, especially for the new Intel Itanium processor. Mick also
2979added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002980
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002981The C APIs to return an object's size have been update to consistently
2982use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2983previous versions, the abstract interfaces used PyXXX_Length and the
2984concrete interfaces used PyXXX_Size. The old names,
2985e.g. PyObject_Length, are still available for backwards compatibility
2986at the API level, but are deprecated.
2987
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002988The PyOS_CheckStack function has been implemented on Windows by
2989Fredrik Lundh. It prevents Python from failing with a stack overflow
2990on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002991
2992The GC changes resulted in creation of two new slots on object,
2993tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002994the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002995
2996The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002997C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002998
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002999PyErr_Format has been updated to automatically calculate the size of
3000the buffer needed to hold the formatted result string. This change
3001prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003002
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003003New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003004
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003005PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3006that are the same as their non-Ex counterparts except they take an
3007extra flag argument that tells them to close the file when done.
3008
3009XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003010
Tim Peters8b092332000-09-05 20:15:25 +00003011
3012Windows Changes
3013---------------
3014
3015New popen2/popen3/peopen4 in os module (see Changed Modules above).
3016
3017os.popen is much more usable on Windows 95 and 98. See Microsoft
3018Knowledge Base article Q150956. The Win9x workaround described there
3019is implemented by the new w9xpopen.exe helper in the root of your
3020Python installation. Note that Python uses this internally; it is not
3021a standalone program.
3022
3023Administrator privileges are no longer required to install Python
3024on Windows NT or Windows 2000. If you have administrator privileges,
3025Python's registry info will be written under HKEY_LOCAL_MACHINE.
3026Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003027under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003028uses of Python, but will prevent some advanced uses from working
3029(for example, running a Python script as an NT service, or possibly
3030from CGI).
3031
3032[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3033installer; instead, it installs the needed Tcl/Tk files directly in the
3034Python directory. If you already have a Tcl/Tk installation, this
3035wastes some disk space (about 4 Megs) but avoids problems with
3036conflicting Tcl/Tk installations, and makes it much easier for Python
3037to ensure that Tcl/Tk can find all its files.
3038
3039[This was new in 1.6] The Windows installer now installs by default in
3040\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3041
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003042
3043Updates to the changes between 1.5.2 and 1.6
3044--------------------------------------------
3045
3046The 1.6 NEWS file can't be changed after the release is done, so here
3047is some late-breaking news:
3048
3049New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3050and changes to getlocale() and setlocale().
3051
3052The new module is now enabled per default.
3053
3054It is not true that the encodings codecs cannot be used for normal
3055strings: the string.encode() (which is also present on 8-bit strings
3056!) allows using them for 8-bit strings too, e.g. to convert files from
3057cp1252 (Windows) to latin-1 or vice-versa.
3058
3059Japanese codecs are available from Tamito KAJIYAMA:
3060http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3061
3062
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003063======================================================================