blob: db38eca9730c872557352bd605d64bfdf3cbe7b8 [file] [log] [blame]
Tim Peterscffed4b2001-11-29 03:26:37 +00001What's New in Python 2.2c1
Tim Petersb3c9af12001-11-17 00:21:57 +00002XXX Release date: ??-Dec-2001 XXX
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum33bab012001-12-05 22:45:48 +00007- Fixed a leak: instance variables declared with __slots__ were never
8 deleted!
9
Guido van Rossum4b800852001-12-03 00:54:52 +000010- The "delete attribute" method of descriptor objects is called
11 __delete__, not __del__. In previous releases, it was mistakenly
12 called __del__, which created an unfortunate overloading condition
13 with finalizers. (The "get attribute" and "set attribute" methods
14 are still called __get__ and __set__, respectively.)
15
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000016- Some subtle issues with the super built-in were fixed:
17
18 (a) When super itself is subclassed, its __get__ method would still
19 return an instance of the base class (i.e., of super).
20
21 (b) super(C, C()).__class__ would return C rather than super. This
22 is confusing. To fix this, I decided to change the semantics of
23 super so that it only applies to code attributes, not to data
24 attributes. After all, overriding data attributes is not
25 supported anyway.
26
27 (c) The __get__ method didn't check whether the argument was an
28 instance of the type used in creation of the super instance.
29
Guido van Rossumcd7b7d62001-12-04 21:02:07 +000030- Previously, hash() of an instance of a subclass of a mutable type
31 (list or dictionary) would return some value, rather than raising
32 TypeError. This has been fixed. Also, directly calling
33 dict.__hash__ and list.__hash__ now raises the same TypeError
34 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000035
Guido van Rossumd331cb52001-12-05 19:46:42 +000036- New-style objects now support deleting their __dict__. This is for
37 all intents and purposes equivalent to assigning a brand new empty
38 dictionary, but saves space if the object is not used further.
39
Tim Petersb3c9af12001-11-17 00:21:57 +000040Core and builtins
41
Tim Peters3caca232001-12-06 06:23:26 +000042- -Qnew now works as documented in PEP 238: when -Qnew is passed on
43 the command line, all occurrences of "/" use true division instead
44 of classic division. See the PEP for details. Note that "all"
45 means all instances in library and 3rd-party modules, as well as in
46 your own code. As the PEP says, -Qnew is intended for use only in
47 educational environments with control over the libraries in use.
48
Tim Petersb3c9af12001-11-17 00:21:57 +000049Extension modules
50
Martin v. Löwis560da622001-11-24 09:24:51 +000051- gc.get_referents was renamed to gc.get_referrers.
52
Tim Petersb3c9af12001-11-17 00:21:57 +000053Library
54
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +000055- webbrowser defaults to netscape.exe on OS/2 now.
56
Martin v. Löwis652e1912001-11-25 14:50:56 +000057- Tix.ResizeHandle exposes detach_widget, hide, and show.
58
Martin v. Löwis714d2e22001-12-02 12:26:03 +000059- The charset alias windows_1252 has been added.
60
Tim Petersb3c9af12001-11-17 00:21:57 +000061Tools/Demos
62
63Build
64
65C API
66
Tim Peterscffed4b2001-11-29 03:26:37 +000067- PyArg_ParseTupleAndKeywords() requires that the number of entries in
68 the keyword list equals the number of argument specifiers. This
69 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
70 dump core in some bad cases. This has been repaired. As a result,
71 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
72 previously went unchallenged.
73
Tim Petersb3c9af12001-11-17 00:21:57 +000074New platforms
75
76Tests
77
78Windows
79
80Mac
81
82
Tim Peters84362bc2001-10-19 17:55:30 +000083What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000084Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000085===========================
86
87Type/class unification and new-style classes
88
Guido van Rossum3d27df02001-11-15 20:27:54 +000089- Multiple inheritance mixing new-style and classic classes in the
90 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000091
92 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000093 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000094
95 The MRO (method resolution order) for each base class is respected
96 according to its kind, but the MRO for the derived class is computed
97 using new-style MRO rules if any base clase is a new-style class.
98 This needs to be documented.
99
Tim Petersa427a2b2001-10-29 22:25:45 +0000100- The new builtin dictionary() constructor, and dictionary type, have
101 been renamed to dict. This reflects a decade of common usage.
102
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000103- dict() now accepts an iterable object producing 2-sequences. For
104 example, dict(d.items()) == d for any dictionary d. The argument,
105 and the elements of the argument, can be any iterable objects.
106
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000107- New-style classes can now have a __del__ method, which is called
108 when the instance is deleted (just like for classic classes).
109
Guido van Rossum12d955c2001-10-26 14:56:06 +0000110- Assignment to object.__dict__ is now possible, for objects that are
111 instances of new-style classes that have a __dict__ (unless the base
112 class forbids it).
113
Guido van Rossumc8e56452001-10-22 00:43:43 +0000114- Methods of built-in types now properly check for keyword arguments
115 (formerly these were silently ignored). The only built-in methods
116 that take keyword arguments are __call__, __init__ and __new__.
117
Guido van Rossum86443212001-10-27 22:28:54 +0000118- The socket function has been converted to a type; see below.
119
Tim Peters84362bc2001-10-19 17:55:30 +0000120Core and builtins
121
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000122- Assignment to __debug__ raises SyntaxError at compile-time. This
123 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000124 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000125
Guido van Rossum12d955c2001-10-26 14:56:06 +0000126- Clarified the error messages for unsupported operands to an operator
127 (like 1 + '').
128
Tim Peters84362bc2001-10-19 17:55:30 +0000129Extension modules
130
Tim Peters5ebfd362001-11-13 23:11:19 +0000131- mmap has a new keyword argument, "access", allowing a uniform way for
132 both Windows and Unix users to create read-only, write-through and
133 copy-on-write memory mappings. This was previously possible only on
134 Unix. A new keyword argument was required to support this in a
135 uniform way because the mmap() signuatures had diverged across
136 platforms. Thanks to Jay T Miller for repairing this!
137
Tim Peters169ded02001-11-03 19:57:21 +0000138- By default, the gc.garbage list now contains only those instances in
139 unreachable cycles that have __del__ methods; in 2.1 it contained all
140 instances in unreachable cycles. "Instances" here has been generalized
141 to include instances of both new-style and old-style classes.
142
Guido van Rossum12d955c2001-10-26 14:56:06 +0000143- The socket module defines a new method for socket objects,
144 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000145 send() until all data has been sent. Also, the socket function has
146 been converted to a subclassable type, like list and tuple (etc.)
147 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000148
149- Various bugfixes to the curses module. There is now a test suite
150 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000151
Guido van Rossum692adf12001-10-30 03:03:03 +0000152- binascii.b2a_base64 no longer places an arbitrary restriction of 57
153 bytes on its input.
154
Tim Peters84362bc2001-10-19 17:55:30 +0000155Library
156
Tim Peters5ebfd362001-11-13 23:11:19 +0000157- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000158 convenience function.
159
Tim Peters75335872001-11-03 19:35:43 +0000160- Symbolic group names in regular expressions must be unique. For
161 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
162 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000163 Python 2.2 detects this error at regexp compilation time;
164 previously, the error went undetected, and results were
165 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
166 pattern.subn() methods have been rewritten in C. Also, an
167 experimental function/method finditer() has been added, which works
168 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000169
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000170- Tix exposes more commands through the classes DirSelectBox,
171 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
172 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
173 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
174
Tim Peters98791af2001-10-23 01:59:54 +0000175- Traceback objects are now scanned by cyclic garbage collection, so
176 cycles created by casual use of sys.exc_info() no longer cause
177 permanent memory leaks (provided garbage collection is enabled).
178
Guido van Rossum49192142001-10-24 20:51:44 +0000179- os.extsep -- a new variable needed by the RISCOS support. It is the
180 separator used by extensions, and is '.' on all platforms except
181 RISCOS, where it is '/'. There is no need to use this variable
182 unless you have a masochistic desire to port your code to RISCOS.
183
Barry Warsaw012852b2001-11-16 16:17:27 +0000184- mimetypes.py has optional support for non-standard, but commonly
185 found types. guess_type() and guess_extension() now accept an
186 optional `strict' flag, defaulting to true, which controls whether
187 recognize non-standard types or not. A few non-standard types we
188 know about have been added. Also, when run as a script, there are
189 new -l and -e options.
190
191- statcache is now deprecated.
192
193- email.Utils.formatdate() now produces the preferred RFC 2822 style
194 dates with numeric timezones (it used to produce obsolete dates
195 hard coded to "GMT" timezone). An optional `localtime' flag is
196 added to produce dates in the local timezone, with daylight savings
197 time properly taken into account.
198
199- In pickle and cPickle, instead of masking errors in load() by
200 transforming them into SystemError, we let the original exception
201 propagate out. Also, implement support for __safe_for_unpickling__
202 in pickle, as it already was supported in cPickle.
203
Tim Peters84362bc2001-10-19 17:55:30 +0000204Tools/Demos
205
206Build
207
Barry Warsaw012852b2001-11-16 16:17:27 +0000208- The dbm module is built using libdb1 if available. The bsddb module
209 is built with libdb3 if available.
210
211- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
212
Tim Peters84362bc2001-10-19 17:55:30 +0000213C API
214
Tim Peters1fc240e2001-10-26 05:06:50 +0000215- New function PySequence_Fast_GET_SIZE() returns the size of a non-
216 NULL result from PySequence_Fast(), more quickly than calling
217 PySequence_Size().
218
Barry Warsaw012852b2001-11-16 16:17:27 +0000219- New argument unpacking function PyArg_UnpackTuple() added.
220
221- New functions PyObject_CallFunctionObjArgs() and
222 PyObject_CallMethodObjArgs() have been added to make it more
223 convenient and efficient to call functions and methods from C.
224
225- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
226 possible that this will propagate errors it didn't before.
227
228- New function PyObject_CheckReadBuffer(), which returns true if its
229 argument supports the single-segment readable buffer interface.
230
Tim Peters84362bc2001-10-19 17:55:30 +0000231New platforms
232
Guido van Rossum86443212001-10-27 22:28:54 +0000233- We've finally confirmed that this release builds on HP-UX 11.00,
234 *with* threads, and passes the test suite.
235
Tim Peters7a33d8b2001-11-05 02:51:07 +0000236- Thanks to a series of patches from Michael Muller, Python may build
237 again under OS/2 Visual Age C++.
238
Guido van Rossum49192142001-10-24 20:51:44 +0000239- Updated RISCOS port by Dietmar Schwertberger.
240
Tim Peters84362bc2001-10-19 17:55:30 +0000241Tests
242
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000243- Added a test script for the curses module. It isn't run automatically;
244 regrtest.py must be run with '-u curses' to enable it.
245
Tim Peters84362bc2001-10-19 17:55:30 +0000246Windows
247
Barry Warsaw012852b2001-11-16 16:17:27 +0000248Mac
249
250- PythonScript has been moved to unsupported and is slated to be
251 removed completely in the next release.
252
253- It should now be possible to build applets that work on both OS9 and
254 OSX.
255
256- The core is now linked with CoreServices not Carbon; as a side
257 result, default 8bit encoding on OSX is now ASCII.
258
259- Python should now build on OSX 10.1.1
260
Tim Peters84362bc2001-10-19 17:55:30 +0000261
Tim Petersabf925f2001-09-28 21:53:42 +0000262What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000263Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000264===========================
265
266Type/class unification and new-style classes
267
Guido van Rossum687ae002001-10-15 22:03:32 +0000268- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000269 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000270 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000271 remains: the __dict__ of a new-style class is a read-only proxy; you
272 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000273 __defined__ attribute of new-style types no longer exists, for lack
274 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000275 future a __cache__ may be resurrected with a similar function, if I
276 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000277
Tim Peters1c9ca872001-10-04 06:43:12 +0000278- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
279 always returned None, even when there was a class docstring).
280
281- doctest now finds and runs docstrings attached to new-style classes,
282 class methods, static methods, and properties.
283
Guido van Rossum9074ef62001-10-16 21:34:49 +0000284Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000285
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000286- A very subtle syntactical pitfall in list comprehensions was fixed.
287 For example: [a+b for a in 'abc', for b in 'def']. The comma in
288 this example is a mistake. Previously, this would silently let 'a'
289 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
290 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
291 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
292 Note that [a for a in <singleton>] is a convoluted way to say
293 [<singleton>] anyway, so it's not like any expressiveness is lost.
294
Guido van Rossum9074ef62001-10-16 21:34:49 +0000295- getattr(obj, name, default) now only catches AttributeError, as
296 documented, rather than returning the default value for all
297 exceptions (which could mask bugs in a __getattr__ hook, for
298 example).
299
Fred Drakecb7a6b52001-10-22 18:41:51 +0000300- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000301 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000302 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000303 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000304
Guido van Rossum1c486092001-10-19 02:05:35 +0000305- unicode(obj) now behaves more like str(obj), accepting arbitrary
306 objects, and calling a __unicode__ method if it exists.
307 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000308 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000309
Barry Warsawf6fb1712001-10-19 05:35:40 +0000310- isinstance() now allows any object as the first argument and a
311 class, a type or something with a __bases__ tuple attribute for the
312 second argument. The second argument may also be a tuple of a
313 class, type, or something with __bases__, in which case isinstance()
314 will return true if the first argument is an instance of any of the
315 things contained in the second argument tuple. E.g.
316
317 isinstance(x, (A, B))
318
319 returns true if x is an instance of A or B.
320
Guido van Rossum9074ef62001-10-16 21:34:49 +0000321Extension modules
322
323- thread.start_new_thread() now returns the thread ID (previously None).
324
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000325- binascii has now two quopri support functions, a2b_qp and b2a_qp.
326
Guido van Rossumc524d952001-10-19 01:31:59 +0000327- readline now supports setting the startup_hook and the
328 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000329
Guido van Rossumc524d952001-10-19 01:31:59 +0000330- os and posix supports chroot(), setgroups() and unsetenv() where
331 available. The stat(), fstat(), statvfs() and fstatvfs() functions
332 now return "pseudo-sequences" -- the various fields can now be
333 accessed as attributes (e.g. os.stat("/").st_mtime) but for
334 backwards compatibility they also behave as a fixed-length sequence.
335 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000336 attributes.
337
338- time: localtime(), gmtime() and strptime() now return a
339 pseudo-sequence similar to the os.stat() return value, with
340 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000341
Guido van Rossum9074ef62001-10-16 21:34:49 +0000342- Decompression objects in the zlib module now accept an optional
343 second parameter to decompress() that specifies the maximum amount
344 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000345
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000346- optional SSL support in the socket module now exports OpenSSL
347 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
348 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000349 automatically seed its PRNG. Also, the keyfile and certfile
350 arguments to socket.ssl() are now optional.
351
352- posixmodule (and by extension, the os module on POSIX platforms) now
353 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000354
Guido van Rossum9074ef62001-10-16 21:34:49 +0000355Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000356
Tim Peters7402f792001-10-02 03:53:41 +0000357- doctest now excludes functions and classes not defined by the module
358 being tested, thanks to Tim Hochberg.
359
Fred Drakecb7a6b52001-10-22 18:41:51 +0000360- HotShot, a new profiler implemented using a C-based callback, has
361 been added. This substantially reduces the overhead of profiling,
362 but it is still quite preliminary. Support modules and
363 documentation will be added in upcoming releases (before 2.2 final).
364
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000365- profile now produces correct output in situations where an exception
366 raised in Python is cleared by C code (e.g. hasattr()). This used
367 to cause wrong output, including spurious claims of recursive
368 functions and attribution of time spent to the wrong function.
369
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000370 The code and documentation for the derived OldProfile and HotProfile
371 profiling classes was removed. The code hasn't worked for years (if
372 you tried to use them, they raised exceptions). OldProfile
373 intended to reproduce the behavior of the profiler Python used more
374 than 7 years ago, and isn't interesting anymore. HotProfile intended
375 to provide a faster profiler (but producing less information), and
376 that's a worthy goal we intend to meet via a different approach (but
377 without losing information).
378
Tim Peterscce092d2001-10-09 05:31:56 +0000379- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000380 a much better system-specific calibration constant. The constant can
381 now be specified in an instance constructor, or as a Profile class or
382 instance variable, instead of by editing profile.py's source code.
383 Calibration must still be done manually (see the docs for the profile
384 module).
385
386 Note that Profile.calibrate() must be overriden by subclasses.
387 Improving the accuracy required exploiting detailed knowledge of
388 profiler internals; the earlier method abstracted away the details
389 and measured a simplified model instead, but consequently computed
390 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000391
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000392- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000393 which indicates whether output is intended for the header 'Q'
394 encoding.
395
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000396- The SocketServer.ThreadingMixIn class now closes the request after
397 finish_request() returns. (Not when it errors out though.)
398
Barry Warsawf6fb1712001-10-19 05:35:40 +0000399- The nntplib module's NNTP.body() method has grown a `file' argument
400 to allow saving the message body to a file.
401
402- The email package has added a class email.Parser.HeaderParser which
403 only parses headers and does not recurse into the message's body.
404 Also, the module/class MIMEAudio has been added for representing
405 audio data (contributed by Anthony Baxter).
406
407- ftplib should be able to handle files > 2GB.
408
409- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
410 ON, and OFF.
411
Fred Drakecb7a6b52001-10-22 18:41:51 +0000412- xml.dom.minidom NodeList objects now support the length attribute
413 and item() method as required by the DOM specifications.
414
Guido van Rossumed554f62001-10-02 23:15:37 +0000415Tools/Demos
416
417- Demo/dns was removed. It no longer serves any purpose; a package
418 derived from it is now maintained by Anthony Baxter, see
419 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000420
Barry Warsawf6fb1712001-10-19 05:35:40 +0000421- The freeze tool has been made more robust, and two new options have
422 been added: -X and -E.
423
Tim Petersabf925f2001-09-28 21:53:42 +0000424Build
425
Barry Warsawf6fb1712001-10-19 05:35:40 +0000426- configure will use CXX in LINKCC if CXX is used to build main() and
427 the system requires to link a C++ main using the C++ compiler.
428
Tim Petersabf925f2001-09-28 21:53:42 +0000429C API
430
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000431- The documentation for the tp_compare slot is updated to require that
432 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
433 not correct. This is not yet enforced but will be enforced in
434 Python 2.3; even later, we may use -2 to indicate errors and +2 for
435 "NotImplemented". Right now, -1 should be used for an error return.
436
Tim Petersd38b1c72001-09-30 05:09:37 +0000437- PyLong_AsLongLong() now accepts int (as well as long) arguments.
438 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
439 as long) arguments.
440
Guido van Rossum3c288632001-10-16 21:13:49 +0000441- PyThread_start_new_thread() now returns a long int giving the thread
442 ID, if one can be calculated; it returns -1 for error, 0 if no
443 thread ID is calculated (this is an incompatible change, but only
444 the thread module used this API). This code has only really been
445 tested on Linux and Windows; other platforms please beware (and
446 report any bugs or strange behavior).
447
Guido van Rossum1c486092001-10-19 02:05:35 +0000448- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
449 input.
450
Tim Petersabf925f2001-09-28 21:53:42 +0000451New platforms
452
453Tests
454
455Windows
456
Tim Peters04cf1d32001-10-09 22:39:40 +0000457- Installer: If you install IDLE, and don't disable file-extension
458 registration, a new "Edit with IDLE" context (right-click) menu entry
459 is created for .py and .pyw files.
460
Tim Peters1ce3cf72001-10-01 17:58:40 +0000461- The signal module now supports SIGBREAK on Windows, thanks to Steven
462 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
463 action remains to call Win32 ExitProcess(). This can be changed via
464 signal.signal(). For example:
465
466 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
467 # (SIGINT) behavior.
468 import signal
469 signal.signal(signal.SIGBREAK,
470 signal.default_int_handler)
471
472 try:
473 while 1:
474 pass
475 except KeyboardInterrupt:
476 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
477 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
478 # program without the possibility for any Python-level cleanup).
479 print "Clean exit"
480
Tim Petersabf925f2001-09-28 21:53:42 +0000481
Tim Petersb07352e2001-09-08 01:25:47 +0000482What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000483Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000484===========================
485
Guido van Rossum808eea72001-09-25 04:15:41 +0000486Type/class unification and new-style classes
487
488- pydoc and inspect are now aware of new-style classes;
489 e.g. help(list) at the interactive prompt now shows proper
490 documentation for all operations on list objects.
491
492- Applications using Jim Fulton's ExtensionClass module can now safely
493 be used with Python 2.2. In particular, Zope 2.4.1 now works with
494 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
495 examples also work again. It is hoped that Gtk and Boost also work
496 with 2.2a4 and beyond. (If you can confirm this, please write
497 webmaster@python.org; if there are still problems, please open a bug
498 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000499
Tim Peters66c1a522001-09-24 21:17:50 +0000500- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
501 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
502 in the constructed property object. fget, fset and fdel weren't
503 discoverable from Python in 2.2a3. __doc__ is new, and allows to
504 associate a docstring with a property.
505
Guido van Rossum808eea72001-09-25 04:15:41 +0000506- Comparison overloading is now more completely implemented. For
507 example, a str subclass instance can properly be compared to a str
508 instance, and it can properly overload comparison. Ditto for most
509 other built-in object types.
510
511- The repr() of new-style classes has changed; instead of <type
512 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
513 *except* for built-in types, which are still rendered as <type
514 'Foo'> (to avoid upsetting existing code that might parse or
515 otherwise rely on repr() of certain type objects).
516
517- The repr() of new-style objects is now always <Foo object at XXX>;
518 previously, it was sometimes <Foo instance at XXX>.
519
520- For new-style classes, what was previously called __getattr__ is now
521 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000522 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000523 one in classic classes is defined which is called only if regular
524 attribute access raises AttributeError; to catch *all* attribute
525 access, you can use __getattribute__ (for new-style classes). If
526 both are defined, __getattribute__ is called first, and if it raises
527 AttributeError, __getattr__ is called.
528
529- The __class__ attribute of new-style objects can be assigned to.
530 The new class must have the same C-level object layout as the old
531 class.
532
533- The builtin file type can be subclassed now. In the usual pattern,
534 "file" is the name of the builtin type, and file() is a new builtin
535 constructor, with the same signature as the builtin open() function.
536 file() is now the preferred way to open a file.
537
538- Previously, __new__ would only see sequential arguments passed to
539 the type in a constructor call; __init__ would see both sequential
540 and keyword arguments. This made no sense whatsoever any more, so
541 now both __new__ and __init__ see all arguments.
542
543- Previously, hash() applied to an instance of a subclass of str or
544 unicode always returned 0. This has been repaired.
545
546- Previously, an operation on an instance of a subclass of an
547 immutable type (int, long, float, complex, tuple, str, unicode),
548 where the subtype didn't override the operation (and so the
549 operation was handled by the builtin type), could return that
550 instance instead a value of the base type. For example, if s was of
551 a str sublass type, s[:] returned s as-is. Now it returns a str
552 with the same value as s.
553
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000554- Provisional support for pickling new-style objects has been added.
555
Guido van Rossum808eea72001-09-25 04:15:41 +0000556Core
557
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000558- file.writelines() now accepts any iterable object producing strings.
559
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000560- PyUnicode_FromEncodedObject() now works very much like
561 PyObject_Str(obj) in that it tries to use __str__/tp_str
562 on the object if the object is not a string or buffer. This
563 makes unicode() behave like str() when applied to non-string/buffer
564 objects.
565
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000566- PyFile_WriteObject now passes Unicode objects to the file's write
567 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000568 of a print statement must support Unicode objects, i.e. they must
569 at least convert them into ASCII strings.
570
Guido van Rossum624c8af2001-09-18 15:21:04 +0000571- Thread scheduling on Solaris should be improved; it is no longer
572 necessary to insert a small sleep at the start of a thread in order
573 to let other runnable threads be scheduled.
574
Tim Petersb07352e2001-09-08 01:25:47 +0000575Library
576
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000577- StringIO.StringIO instances and cStringIO.StringIO instances support
578 read character buffer compatible objects for their .write() methods.
579 These objects are converted to strings and then handled as such
580 by the instances.
581
Barry Warsaw2f600732001-09-24 04:28:10 +0000582- The "email" package has been added. This is basically a port of the
583 mimelib package <http://sf.net/projects/mimelib> with API changes
584 and some implementations updated to use iterators and generators.
585
Tim Peters8a9c2842001-09-22 21:30:22 +0000586- difflib.ndiff() and difflib.Differ.compare() are generators now. This
587 restores the ability of Tools/scripts/ndiff.py to start producing output
588 before the entire comparison is complete.
589
Barry Warsaw58b072d2001-09-22 04:44:21 +0000590- StringIO.StringIO instances and cStringIO.StringIO instances support
591 iteration just like file objects (i.e. their .readline() method is
592 called for each iteration until it returns an empty string).
593
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000594- The codecs module has grown four new helper APIs to access
595 builtin codecs: getencoder(), getdecoder(), getreader(),
596 getwriter().
597
Guido van Rossum624c8af2001-09-18 15:21:04 +0000598- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
599 simplifies writing XML RPC servers.
600
Barry Warsaw647d5e82001-09-28 17:01:02 +0000601- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000602 after interpretation of symbolic links. On non-Unix systems, this
603 is an alias for os.path.abspath().
604
Tim Peters16a77ad2001-09-08 04:00:12 +0000605- operator.indexOf() (PySequence_Index() in the C API) now works with any
606 iterable object.
607
Guido van Rossum624c8af2001-09-18 15:21:04 +0000608- smtplib now supports various authentication and security features of
609 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000610
Guido van Rossum624c8af2001-09-18 15:21:04 +0000611- hmac: a new module implementing keyed hashing for message
612 authentication.
613
614- mimetypes now recognizes more extensions and file types. At the
615 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000616
Guido van Rossum624c8af2001-09-18 15:21:04 +0000617- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000618 Python 2.2 bytecode generation. It has also been promoted from a
619 Tool to a standard library package. (Tools/compiler still exists as
620 a sample driver.)
621
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000622Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000623
Tim Petersb07352e2001-09-08 01:25:47 +0000624Build
625
Guido van Rossum624c8af2001-09-18 15:21:04 +0000626- Large file support (LFS) is now automatic when the platform supports
627 it; no more manual configuration tweaks are needed. On Linux, at
628 least, it's possible to have a system whose C library supports large
629 files but whose kernel doesn't; in this case, large file support is
630 still enabled but doesn't do you any good unless you upgrade your
631 kernel or share your Python executable with another system whose
632 kernel has large file support.
633
634- The configure script now supplies plausible defaults in a
635 cross-compilation environment. This doesn't mean that the supplied
636 values are always correct, or that cross-compilation now works
637 flawlessly -- but it's a first step (and it shuts up most of
638 autoconf's warnings about AC_TRY_RUN).
639
640- The Unix build is now a bit less chatty, courtesy of the parser
641 generator. The build is completely silent (except for errors) when
642 using "make -s", thanks to a -q option to setup.py.
643
Tim Petersb07352e2001-09-08 01:25:47 +0000644C API
645
Guido van Rossum624c8af2001-09-18 15:21:04 +0000646- The "structmember" API now supports some new flag bits to deny read
647 and/or write access to attributes in restricted execution mode.
648
Tim Petersb07352e2001-09-08 01:25:47 +0000649New platforms
650
Guido van Rossum624c8af2001-09-18 15:21:04 +0000651- Compaq's iPAQ handheld, running the "familiar" Linux distribution
652 (http://familiar.handhelds.org).
653
Tim Petersb07352e2001-09-08 01:25:47 +0000654Tests
655
Tim Peters8a9c2842001-09-22 21:30:22 +0000656- The "classic" standard tests, which work by comparing stdout to
657 an expected-output file under Lib/test/output/, no longer stop at
658 the first mismatch. Instead the test is run to completion, and a
659 variant of ndiff-style comparison is used to report all differences.
660 This is much easier to understand than the previous style of reporting.
661
662- The unittest-based standard tests now use regrtest's test_main()
663 convention, instead of running as a side-effect of merely being
664 imported. This allows these tests to be run in more natural and
665 flexible ways as unittests, outside the regrtest framework.
666
667- regrtest.py is much better integrated with unittest and doctest now,
668 especially in regard to reporting errors.
669
Tim Petersb07352e2001-09-08 01:25:47 +0000670Windows
671
Guido van Rossum624c8af2001-09-18 15:21:04 +0000672- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000673 that support it (NTFS under Windows 2000). See "What's New in
674 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000675
Tim Petersb07352e2001-09-08 01:25:47 +0000676
Tim Petersedc99312001-08-22 21:36:50 +0000677What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000678Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000679===========================
680
681Core
682
Tim Peters9fffa3e2001-09-04 05:14:19 +0000683- Conversion of long to float now raises OverflowError if the long is too
684 big to represent as a C double.
685
Tim Peters32f453e2001-09-03 08:35:41 +0000686- The 3-argument builtin pow() no longer allows a third non-None argument
687 if either of the first two arguments is a float, or if both are of
688 integer types and the second argument is negative (in which latter case
689 the arguments are converted to float, so this is really the same
690 restriction).
691
Tim Peters5d2b77c2001-09-03 05:47:38 +0000692- The builtin dir() now returns more information, and sometimes much
693 more, generally naming all attributes of an object, and all attributes
694 reachable from the object via its class, and from its class's base
695 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
696 an empty list. In 2.2a3,
697
698 >>> dir([])
699 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
700 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
701 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
702 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
703 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
704 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
705 'reverse', 'sort']
706
707 dir(module) continues to return only the module's attributes, though.
708
Tim Petersbdee63f2001-09-02 03:40:59 +0000709- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000710 than raising OverflowError. This is a partial implementation of PEP
711 237. You can use -Wdefault::OverflowWarning to enable a warning for
712 this situation, and -Werror::OverflowWarning to revert to the old
713 OverflowError exception.
714
Guido van Rossum61c345f2001-09-04 03:26:15 +0000715- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000716 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000717 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
718 -Qold, meaning the / operator has its classic meaning and no
719 warnings are issued. Using -Qwarn issues a run-time warning about
720 all uses of classic division for int and long arguments; -Qwarnall
721 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +0000722 (for use with fixdiv.py).
723 [Note: the remainder of this paragraph (preserved below) became
724 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
725 <obsolete>
726 Using -Qnew is questionable; it turns on new division by default, but
727 only in the __main__ module. You can usefully combine -Qwarn or
728 -Qwarnall and -Qnew: this gives the __main__ module new division, and
729 warns about classic division everywhere else.
730 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +0000731
Tim Petersbdee63f2001-09-02 03:40:59 +0000732- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000733 long, float, str, unicode, and tuple. (The types complex, list and
734 dictionary can also be subclassed; this was introduced earlier.)
735 Note that restrictions apply when subclassing immutable built-in
736 types: you can only affect the value of the instance by overloading
737 __new__. You can add mutable attributes, and the subclass instances
738 will have a __dict__ attribute, but you cannot change the "value"
739 (as implemented by the base class) of an immutable subclass instance
740 once it is created.
741
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000742- The dictionary constructor now takes an optional argument, a
743 mapping-like object, and initializes the dictionary from its
744 (key, value) pairs.
745
Tim Petersbdee63f2001-09-02 03:40:59 +0000746- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000747 "cooperative super calls" in a multiple inheritance setting. For an
748 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
749
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000750- A new built-in type, property, has been added. This enables the
751 creation of "properties". These are attributes implemented by
752 getter and setter functions (or only one of these for read-only or
753 write-only attributes), without the need to override __getattr__.
754 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000755
Tim Petersbdee63f2001-09-02 03:40:59 +0000756- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000757 liberalized, to allow leading zeroes. Examples of literals now
758 legal that were SyntaxErrors before:
759
760 00.0 0e3 0100j 07.5 00000000000000000008.
761
Tim Petersbdee63f2001-09-02 03:40:59 +0000762- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000763 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
764
Tim Petersedc99312001-08-22 21:36:50 +0000765Library
766
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000767- telnetlib includes symbolic names for the options, and support for
768 setting an option negotiation callback.
769
Tim Petersa40c7932001-09-05 22:36:56 +0000770- The new C standard no longer requires that math libraries set errno to
771 ERANGE on overflow. For platform libraries that exploit this new
772 freedom, Python's overflow-checking was wholly broken. A new overflow-
773 checking scheme attempts to repair that, but may not be reliable on all
774 platforms (C doesn't seem to provide anything both useful and portable
775 in this area anymore).
776
Martin v. Löwis44f86962001-09-05 13:44:54 +0000777- Asynchronous timeout actions are available through the new class
778 threading.Timer.
779
Tim Peters78526162001-09-05 00:53:45 +0000780- math.log and math.log10 now return sensible results for even huge
781 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
782
Tim Petersbdee63f2001-09-02 03:40:59 +0000783- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000784 currently held. See the docs for the imp module.
785
Tim Petersbdee63f2001-09-02 03:40:59 +0000786- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000787 dumps containing ints written on platforms where Python ints are 8 bytes.
788 When read on a box where Python ints are 4 bytes, such values are
789 converted to Python longs.
790
Tim Petersbdee63f2001-09-02 03:40:59 +0000791- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000792 code objects is no longer allowed. This plugs a security hole.
793
Steve Purcell6091cd62001-09-06 16:05:17 +0000794- unittest.TestResult instances no longer store references to tracebacks
795 generated by test failures. This prevents unexpected dangling references
796 to objects that should be garbage collected between tests.
797
Tim Petersedc99312001-08-22 21:36:50 +0000798Tools
799
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000800- Tools/scripts/fixdiv.py has been added which can be used to fix
801 division operators as per PEP 238.
802
Tim Petersedc99312001-08-22 21:36:50 +0000803Build
804
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000805- If you are an adventurous person using Mac OS X you may want to look at
806 Mac/OSX. There is a Makefile there that will build Python as a real Mac
807 application, which can be used for experimenting with Carbon or Cocoa.
808 Discussion of this on pythonmac-sig, please.
809
Tim Peters7eea37e2001-09-04 22:08:56 +0000810C API
811
812- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000813
Tim Peters9fffa3e2001-09-04 05:14:19 +0000814- Note that PyLong_AsDouble can fail! This has always been true, but no
815 callers checked for it. It's more likely to fail now, because overflow
816 errors are properly detected now. The proper way to check:
817
818 double x = PyLong_AsDouble(some_long_object);
819 if (x == -1.0 && PyErr_Occurred()) {
820 /* The conversion failed. */
821 }
822
Tim Petersbdee63f2001-09-02 03:40:59 +0000823- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000824 compile but will not participate in GC. To upgrade an extension
825 module:
826
827 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000828
Neil Schemenauer4042c692001-08-30 15:38:01 +0000829 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
830 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000831
Neil Schemenauer4042c692001-08-30 15:38:01 +0000832 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
833 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000834
Neil Schemenauer4042c692001-08-30 15:38:01 +0000835 - remove PyGC_HEAD_SIZE from object size calculations
836
837 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
838
Tim Petersbdee63f2001-09-02 03:40:59 +0000839- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000840 These can be used safely to construct string objects from a
841 sprintf-style format string (similar to the format string supported
842 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000843
Tim Petersedc99312001-08-22 21:36:50 +0000844New platforms
845
Tim Petersb7da0902001-09-02 23:01:43 +0000846- Stephen Hansen contributed patches sufficient to get a clean compile
847 under Borland C (Windows), but he reports problems running it and ran
848 out of time to complete the port. Volunteers? Expect a MemoryError
849 when importing the types module; this is probably shallow, and
850 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000851
Tim Petersedc99312001-08-22 21:36:50 +0000852Tests
853
854Windows
855
Tim Peters6e13a562001-09-06 00:32:15 +0000856- Large file support is now enabled on Win32 platforms as well as on
857 Win64. This means that, for example, you can use f.tell() and f.seek()
858 to manipulate files larger than 2 gigabytes (provided you have enough
859 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000860 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
861 filesize limit, and large file support makes no difference there.
862 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
863 NTFS has no practical limit on file size, and files of any size can be
864 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000865
Tim Petersbdee63f2001-09-02 03:40:59 +0000866- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000867 points to command.com (patch from Brian Quinlan).
868
Tim Petersedc99312001-08-22 21:36:50 +0000869
Tim Peters20f51a72001-07-21 02:31:40 +0000870What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000871Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000872===========================
873
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000874Build
875
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000876- Tim Peters developed a brand new Windows installer using Wise 8.1,
877 generously donated to us by Wise Solutions.
878
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000879- configure supports a new option --enable-unicode, with the values
880 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
881 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000882
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000883- A new configure option --enable-framework builds a Mac OS X framework,
884 which "make frameworkinstall" will install. This provides a starting
885 point for more mac-like functionality, join pythonmac-sig@python.org
886 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000887
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000888- The NeXT platform is no longer supported.
889
890- The `new' module is now statically linked.
891
Tim Peters0afb6092001-08-15 06:06:44 +0000892Tools
893
894- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000895 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000896 the module docstring for details.
897
Tim Peters20f51a72001-07-21 02:31:40 +0000898Tests
899
Tim Peters5e824c32001-08-12 22:25:01 +0000900- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000901 platforms, allowing to give clearer test result output. regrtest
902 also has optional --use/-u switch to run normally disabled tests
903 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000904
Tim Peters20f51a72001-07-21 02:31:40 +0000905- Several new tests in the standard test suite, with special thanks to
906 Nick Mathewson.
907
908Core
909
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000910- The floor division operator // has been added as outlined in PEP
911 238. The / operator still provides classic division (and will until
912 Python 3.0) unless "from __future__ import division" is included, in
913 which case the / operator will provide true division. The operator
914 module provides truediv() and floordiv() functions. Augmented
915 assignment variants are included, as are the equivalent overloadable
916 methods and C API methods. See the PEP for a full discussion:
917 <http://python.sf.net/peps/pep-0238.html>
918
Tim Peters6cd6a822001-08-17 22:11:27 +0000919- Future statements are now effective in simulated interactive shells
920 (like IDLE). This should "just work" by magic, but read Michael
921 Hudson's "Future statements in simulated shells" PEP 264 for full
922 details: <http://python.sf.net/peps/pep-0264.html>.
923
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000924- The type/class unification (PEP 252-253) was integrated into the
925 trunk and is not so tentative any more (the exact specification of
926 some features is still tentative). A lot of work has done on fixing
927 bugs and adding robustness and features (performance still has to
928 come a long way).
929
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000930- Warnings about a mismatch in the Python API during extension import
931 now use the Python warning framework (which makes it possible to
932 write filters for these warnings).
933
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000934- A function's __dict__ (aka func_dict) will now always be a
935 dictionary. It used to be possible to delete it or set it to None,
936 but now both actions raise TypeErrors. It is still legal to set it
937 to a dictionary object. Getting func.__dict__ before any attributes
938 have been assigned now returns an empty dictionary instead of None.
939
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000940- A new command line option, -E, was added which disables the use of
941 all environment variables, or at least those that are specifically
942 significant to Python. Usually those have a name starting with
943 "PYTHON". This was used to fix a problem where the tests fail if
944 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
945 older distribution.
946
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000947Library
948
Tim Peters5e824c32001-08-12 22:25:01 +0000949- New class Differ and new functions ndiff() and restore() in difflib.py.
950 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000951 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000952
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000953- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
954 value using the minimal quoting required for the value; more
955 reliable than using xml.sax.saxutils.escape() for attribute values.
956
957- Readline completion support for cmd.Cmd was added.
958
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000959- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
960
961- Added function threading.BoundedSemaphore()
962
963- Added Ka-Ping Yee's cgitb.py module.
964
965- The `new' module now exposes the CO_xxx flags.
966
Martin v. Löwis560da622001-11-24 09:24:51 +0000967- The gc module offers the get_referents function.
968
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000969New platforms
970
971C API
972
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000973- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
974 which provide a cross-platform implementations for the
975 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
976 the standard sprintf() and vsprintf() C lib APIs, these versions
977 apply bounds checking on the used buffer which enhances protection
978 against buffer overruns.
979
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000980- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000981 and extensions using different Unicode widths is rendered next to
982 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000983 will result in an ImportError. Unicode extensions writers must make
984 sure to check the Unicode width compatibility in their extensions by
985 using at least one of the mangled Unicode APIs in the extension.
986
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000987- Two new flags METH_NOARGS and METH_O are available in method definition
988 tables to simplify implementation of methods with no arguments and a
989 single untyped argument. Calling such methods is more efficient than
990 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
991 deprecated.
992
Tim Petersc1731372001-08-04 08:12:36 +0000993Windows
994
995- "import module" now compiles module.pyw if it exists and nothing else
996 relevant is found.
997
Tim Peters20f51a72001-07-21 02:31:40 +0000998
Guido van Rossum55a78992001-07-17 17:22:32 +0000999What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001000Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001001===========================
1002
1003Core
Tim Petersa814db52001-05-14 07:05:58 +00001004
Tim Peters6d6c1a32001-08-02 04:15:00 +00001005- TENTATIVELY, a large amount of code implementing much of what's
1006 described in PEP 252 (Making Types Look More Like Classes) and PEP
1007 253 (Subtyping Built-in Types) was added. This will be released
1008 with Python 2.2a1. Documentation will be provided separately
1009 through http://www.python.org/2.2/. The purpose of releasing this
1010 with Python 2.2a1 is to test backwards compatibility. It is
1011 possible, though not likely, that a decision is made not to release
1012 this code as part of 2.2 final, if any serious backwards
1013 incompapatibilities are found during alpha testing that cannot be
1014 repaired.
1015
Guido van Rossum55a78992001-07-17 17:22:32 +00001016- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001017 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001018 more 'yield' statements. See PEP 255. Since this adds a new
1019 keyword to the language, this feature must be enabled by including a
1020 future statement: "from __future__ import generators" (see PEP 236).
1021 Generators will become a standard feature in a future release
1022 (probably 2.3). Without this future statement, 'yield' remains an
1023 ordinary identifier, but a warning is issued each time it is used.
1024 (These warnings currently don't conform to the warnings framework of
1025 PEP 230; we intend to fix this in 2.2a2.)
1026
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001027- The UTF-16 codec was modified to be more RFC compliant. It will now
1028 only remove BOM characters at the start of the string and then
1029 only if running in native mode (UTF-16-LE and -BE won't remove a
1030 leading BMO character).
1031
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001032- Strings now have a new method .decode() to complement the already
1033 existing .encode() method. These two methods provide direct access
1034 to the corresponding decoders and encoders of the registered codecs.
1035
1036 To enhance the usability of the .encode() method, the special
1037 casing of Unicode object return values was dropped (Unicode objects
1038 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001039
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001040 Both methods will now return whatever the codec in charge of the
1041 requested encoding returns as object, e.g. Unicode codecs will
1042 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1043 will return u"äöü"). This enables codec writer to create codecs
1044 for various simple to use conversions.
1045
1046 New codecs were added to demonstrate these new features (the .encode()
1047 and .decode() columns indicate the type of the returned objects):
1048
1049 Name | .encode() | .decode() | Description
1050 ----------------------------------------------------------------------
1051 uu | string | string | UU codec (e.g. for email)
1052 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001053 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001054 zlib | string | string | zlib compression
1055 hex | string | string | 2-byte hex codec
1056 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1057
Mark Hammond2a0af792001-05-14 03:09:36 +00001058- Some operating systems now support the concept of a default Unicode
1059 encoding for file system operations. Notably, Windows supports 'mbcs'
1060 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001061 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001062 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001063
1064 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001065 functions that return filenames (such as os.listdir()) to return Python
1066 string objects pre-encoded using the default file system encoding for
1067 the platform. As this encoding is likely to be different from Python's
1068 default encoding, converting this name to a Unicode object before passing
1069 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001070 would attempt to use its default encoding (generally ASCII) rather than
1071 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001072
Tim Petersa814db52001-05-14 07:05:58 +00001073 In general, this change simply removes surprises when working with
1074 Unicode and the file system, making these operations work as you expect,
1075 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001076 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001077
Tim Peters61dff2b2001-05-08 15:43:37 +00001078- Float (and complex) literals in source code were evaluated to full
1079 precision only when running from a .py file; the same code loaded from a
1080 .pyc (or .pyo) file could suffer numeric differences starting at about the
1081 12th significant decimal digit. For example, on a machine with IEEE-754
1082 floating arithmetic,
1083
1084 x = 9007199254740992.0
1085 print long(x)
1086
1087 printed 9007199254740992 if run directly from .py, but 9007199254740000
1088 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1089 str(float) instead of repr(float) when building code objects. marshal
1090 now uses repr(float) instead, which should reproduce floats to full
1091 machine precision (assuming the platform C float<->string I/O conversion
1092 functions are of good quality).
1093
1094 This may cause floating-point results to change in some cases, and
1095 usually for the better, but may also cause numerically unstable
1096 algorithms to break.
1097
Tim Peters2f228e72001-05-13 00:19:31 +00001098- The implementation of dicts suffers fewer collisions, which has speed
1099 benefits. However, the order in which dict entries appear in dict.keys(),
1100 dict.values() and dict.items() may differ from previous releases for a
1101 given dict. Nothing is defined about this order, so no program should
1102 rely on it. Nevertheless, it's easy to write test cases that rely on the
1103 order by accident, typically because of printing the str() or repr() of a
1104 dict to an "expected results" file. See Lib/test/test_support.py's new
1105 sortdict(dict) function for a simple way to display a dict in sorted
1106 order.
1107
Tim Peters7a3bfc32001-06-12 01:22:22 +00001108- Many other small changes to dicts were made, resulting in faster
1109 operation along the most common code paths.
1110
Guido van Rossum10315822001-05-01 20:54:30 +00001111- Dictionary objects now support the "in" operator: "x in dict" means
1112 the same as dict.has_key(x).
1113
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001114- The update() method of dictionaries now accepts generic mapping
1115 objects. Specifically the argument object must support the .keys()
1116 and __getitem__() methods. This allows you to say, for example,
1117 {}.update(UserDict())
1118
Guido van Rossum10315822001-05-01 20:54:30 +00001119- Iterators were added; this is a generalized way of providing values
1120 to a for loop. See PEP 234. There's a new built-in function iter()
1121 to return an iterator. There's a new protocol to get the next value
1122 from an iterator using the next() method (in Python) or the
1123 tp_iternext slot (in C). There's a new protocol to get iterators
1124 using the __iter__() method (in Python) or the tp_iter slot (in C).
1125 Iterating (i.e. a for loop) over a dictionary generates its keys.
1126 Iterating over a file generates its lines.
1127
Tim Petersf553f892001-05-01 20:45:31 +00001128- The following functions were generalized to work nicely with iterator
1129 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001130 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001131 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1132 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001133 join() method of strings
1134 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001135 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1136 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001137 right-hand side of assignment statements with multiple targets, such as
1138 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001139
Tim Petersd85e1022001-05-11 21:51:48 +00001140- Accessing module attributes is significantly faster (for example,
1141 random.random or os.path or yourPythonModule.yourAttribute).
1142
Tim Peterse63415e2001-05-08 04:38:29 +00001143- Comparing dictionary objects via == and != is faster, and now works even
1144 if the keys and values don't support comparisons other than ==.
1145
Tim Peters95bf9392001-05-10 08:32:44 +00001146- Comparing dictionaries in ways other than == and != is slower: there were
1147 insecurities in the dict comparison implementation that could cause Python
1148 to crash if the element comparison routines for the dict keys and/or
1149 values mutated the dicts. Making the code bulletproof slowed it down.
1150
Tim Peterseb28ef22001-06-02 05:27:19 +00001151- Collisions in dicts are resolved via a new approach, which can help
1152 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001153 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001154 faster now. Thanks to Christian Tismer for pointing out the cause and
1155 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001156
Tim Peters52e155e2001-06-16 05:42:57 +00001157- repr() is much faster for large containers (dict, list, tuple).
1158
1159
Tim Petersa814db52001-05-14 07:05:58 +00001160Library
1161
Fred Drake960fdf92001-07-20 18:38:26 +00001162- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1163 were added to the string module. These a locale-indenpendent
1164 constants, unlike letters, lowercase, and uppercase. These are now
1165 use in appropriate locations in the standard library.
1166
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001167- The flags used in dlopen calls can now be configured using
1168 sys.setdlopenflags and queried using sys.getdlopenflags.
1169
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001170- Fredrik Lundh's xmlrpclib is now a standard library module. This
1171 provides full client-side XML-RPC support. In addition,
1172 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1173 one asyncore-based). Thanks to Eric Raymond for the documentation.
1174
Guido van Rossum643d3912001-07-05 14:46:25 +00001175- The xrange() object is simplified: it no longer supports slicing,
1176 repetition, comparisons, efficient 'in' checking, the tolist()
1177 method, or the start, stop and step attributes. See PEP 260.
1178
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001179- A new function fnmatch.filter to filter lists of file names was added.
1180
Barry Warsawffd674d2001-05-22 16:00:10 +00001181- calendar.py uses month and day names based on the current locale.
1182
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001183- strop is now *really* obsolete (this was announced before with 1.6),
1184 and issues DeprecationWarning when used (except for the four items
1185 that are still imported into string.py).
1186
Tim Petersa814db52001-05-14 07:05:58 +00001187- Cookie.py now sorts key+value pairs by key in output strings.
1188
1189- pprint.isrecursive(object) didn't correctly identify recursive objects.
1190 Now it does.
1191
Tim Peters95b3f782001-05-14 18:39:41 +00001192- pprint functions now much faster for large containers (tuple, list, dict).
1193
Tim Peters7b9542a2001-06-10 23:40:19 +00001194- New 'q' and 'Q' format codes in the struct module, corresponding to C
1195 types "long long" and "unsigned long long" (on Windows, __int64). In
1196 native mode, these can be used only when the platform C compiler supports
1197 these types (when HAVE_LONG_LONG is #define'd by the Python config
1198 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001199 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1200 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001201
Guido van Rossum83213cc2001-06-12 16:48:52 +00001202- The site module installs a new built-in function 'help' that invokes
1203 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1204 it displays a message reminding the user to use 'help()' or
1205 'help(object)'.
1206
Tim Petersa814db52001-05-14 07:05:58 +00001207Tests
1208
1209- New test_mutants.py runs dict comparisons where the key and value
1210 comparison operators mutute the dicts randomly during comparison. This
1211 rapidly causes Python to crash under earlier releases (not for the faint
1212 of heart: it can also cause Win9x to freeze or reboot!).
1213
1214- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001215 pprint.isreadable() return sensible results. Also verifies that simple
1216 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001217
Tim Peters4324aa32001-05-28 22:30:08 +00001218C API
1219
1220- Removed the unused last_is_sticky argument from the internal
1221 _PyTuple_Resize(). If this affects you, you were cheating.
1222
1223
Guido van Rossum55a78992001-07-17 17:22:32 +00001224======================================================================
1225
1226
Guido van Rossumffe13be2001-04-16 18:46:45 +00001227What's New in Python 2.1 (final)?
1228=================================
1229
1230We only changed a few things since the last release candidate, all in
1231Python library code:
1232
1233- A bug in the locale module was fixed that affected locales which
1234 define no grouping for numeric formatting.
1235
1236- A few bugs in the weakref module's implementations of weak
1237 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1238 and the test suite was updated to check for these bugs.
1239
1240- An old bug in the os.path.walk() function (introduced in Python
1241 2.0!) was fixed: a non-existent file would cause an exception
1242 instead of being ignored.
1243
1244- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1245 PyChecker.
1246
1247
Guido van Rossum5b08f132001-04-16 02:05:23 +00001248What's New in Python 2.1c2?
1249===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001250
Guido van Rossum5b08f132001-04-16 02:05:23 +00001251A flurry of small changes, and one showstopper fixed in the nick of
1252time made it necessary to release another release candidate. The list
1253here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001254
Guido van Rossum5b08f132001-04-16 02:05:23 +00001255Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001256
Guido van Rossum5b08f132001-04-16 02:05:23 +00001257- Tim discovered a nasty bug in the dictionary code, caused by
1258 PyDict_Next() calling dict_resize(), and the GC code's use of
1259 PyDict_Next() violating an assumption in dict_items(). This was
1260 fixed with considerable amounts of band-aid, but the net effect is a
1261 saner and more robust implementation.
1262
1263- Made a bunch of symbols static that were accidentally global.
1264
1265Build and Ports
1266
1267- The setup.py script didn't check for a new enough version of zlib
1268 (1.1.3 is needed). Now it does.
1269
1270- Changed "make clean" target to also remove shared libraries.
1271
1272- Added a more general warning about the SGI Irix optimizer to README.
1273
1274Library
1275
1276- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1277 omitted the slash between host and file.html.
1278
1279- The mailbox module's _Mailbox class contained a completely broken
1280 and undocumented seek() method. Ripped it out.
1281
1282- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1283 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1284
1285- Fixed a few last-minute bugs in unittest.
1286
1287Extensions
1288
1289- Reverted the patch to the OpenSSL code in socketmodule.c to support
1290 RAND_status() and the EGD, and the subsequent patch that tried to
1291 fix it for pre-0.9.5 versions; the problem with the patch is that on
1292 some systems it issues a warning whenever socket is imported, and
1293 that's unacceptable.
1294
1295Tests
1296
1297- Fixed the pickle tests to work with "import test.test_pickle".
1298
1299- Tweaked test_locale.py to actually run the test Windows.
1300
1301- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1302 not "wb" (which is not a valid mode at all).
1303
1304- Fix pstats browser crashes. Import readline if it exists to make
1305 the user interface nicer.
1306
1307- Add "import thread" to the top of test modules that import the
1308 threading module (test_asynchat and test_threadedtempfile). This
1309 prevents test failures caused by a broken threading module resulting
1310 from a previously caught failed import.
1311
1312- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1313 needed on some platforms (e.g. Solaris 8) when the tests are run
1314 twice in succession.
1315
1316- Skip rather than fail test_sunaudiodev if no audio device is found.
1317
1318
1319What's New in Python 2.1c1?
1320===========================
1321
1322This list was significantly updated when 2.1c2 was released; the 2.1c1
1323release didn't mention most changes that were actually part of 2.1c1:
1324
1325Legal
1326
1327- Copyright was assigned to the Python Software Foundation (PSF) and a
1328 PSF license (very similar to the CNRI license) was added.
1329
1330- The CNRI copyright notice was updated to include 2001.
1331
1332Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001333
Guido van Rossumc9932722001-04-12 02:31:27 +00001334- After a public outcry, assignment to __debug__ is no longer illegal;
1335 instead, a warning is issued. It will become illegal in 2.2.
1336
Guido van Rossum5b08f132001-04-16 02:05:23 +00001337- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1338 "%#x" now always prepends "0x", even if the value is zero.
1339
1340- Fixed some nits in the bytecode compiler.
1341
1342- Fixed core dumps when calling certain kinds of non-functions.
1343
1344- Fixed various core dumps caused by reference count bugs.
1345
1346Build and Ports
1347
1348- Use INSTALL_SCRIPT to install script files.
1349
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001350- New port: SCO Unixware 7, by Billy G. Allie.
1351
Guido van Rossum5b08f132001-04-16 02:05:23 +00001352- Updated RISCOS port.
1353
1354- Updated BeOS port and notes.
1355
1356- Various other porting problems resolved.
1357
1358Library
1359
1360- The TERMIOS and SOCKET modules are now truly obsolete and
1361 unnecessary. Their symbols are incorporated in the termios and
1362 socket modules.
1363
1364- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1365 better tests for pickling.
1366
1367- threading: make Condition.wait() robust against KeyboardInterrupt.
1368
1369- zipfile: add support to zipfile to support opening an archive
1370 represented by an open file rather than a file name. Fix bug where
1371 the archive was not properly closed. Fixed a bug in this bugfix
1372 where flush() was called for a read-only file.
1373
1374- imputil: added an uninstall() method to the ImportManager.
1375
1376- Canvas: fixed bugs in lower() and tkraise() methods.
1377
1378- SocketServer: API change (added overridable close_request() method)
1379 so that the TCP server can explicitly close the request.
1380
1381- pstats: Eric Raymond added a simple interactive statistics browser,
1382 invoked when the module is run as a script.
1383
1384- locale: fixed a problem in format().
1385
1386- webbrowser: made it work when the BROWSER environment variable has a
1387 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1388 KDE 2. Fixed some other nits.
1389
1390- unittest: changes to allow using a different exception than
1391 AssertionError, and added a few more function aliases. Some other
1392 small changes.
1393
1394- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1395
1396- asynchat: fixed a critical bug in asynchat that slipped through the
1397 2.1b2 release. Fixed another rare bug.
1398
1399- Fix some unqualified except: clauses (always a bad code example).
1400
1401XML
1402
1403- pyexpat: new API get_version_string().
1404
1405- Fixed some minidom bugs.
1406
1407Extensions
1408
1409- Fixed a core dump in _weakref. Removed the weakref.mapping()
1410 function (it adds nothing to the API).
1411
1412- Rationalized the use of header files in the readline module, to make
1413 it compile (albeit with some warnings) with the very recent readline
1414 4.2, without breaking for earlier versions.
1415
1416- Hopefully fixed a buffering problem in linuxaudiodev.
1417
1418- Attempted a fix to make the OpenSSL support in the socket module
1419 work again with pre-0.9.5 versions of OpenSSL.
1420
1421Tests
1422
1423- Added a test case for asynchat and asyncore.
1424
1425- Removed coupling between tests where one test failing could break
1426 another.
1427
1428Tools
1429
1430- Ping added an interactive help browser to pydoc, fixed some nits
1431 in the rest of the pydoc code, and added some features to his
1432 inspect module.
1433
1434- An updated python-mode.el version 4.1 which integrates Ken
1435 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1436 much nicer in XEmacs and Emacs. When stepping through your program
1437 with pdb, in either the shell window or the *Python* window, the
1438 source file and line will be tracked by an arrow. Very cool!
1439
1440- IDLE: syntax warnings in interactive mode are changed into errors.
1441
1442- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001443 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001444
1445- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001446
Barry Warsaw11e89c72001-04-11 20:37:57 +00001447
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001448What's New in Python 2.1 beta 2?
1449================================
1450
Guido van Rossum053ae352001-03-22 14:17:21 +00001451(Unlisted are many fixed bugs, more documentation, etc.)
1452
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001453Core language, builtins, and interpreter
1454
Guido van Rossum053ae352001-03-22 14:17:21 +00001455- The nested scopes work (enabled by "from __future__ import
1456 nested_scopes") is completed; in particular, the future now extends
1457 into code executed through exec, eval() and execfile(), and into the
1458 interactive interpreter.
1459
1460- When calling a base class method (e.g. BaseClass.__init__(self)),
1461 this is now allowed even if self is not strictly spoken a class
1462 instance (e.g. when using metaclasses or the Don Beaudry hook).
1463
1464- Slice objects are now comparable but not hashable; this prevents
1465 dict[:] from being accepted but meaningless.
1466
1467- Complex division is now calculated using less braindead algorithms.
1468 This doesn't change semantics except it's more likely to give useful
1469 results in extreme cases. Complex repr() now uses full precision
1470 like float repr().
1471
1472- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1473
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001474- It is illegal to assign to the name __debug__, which is set when the
1475 interpreter starts. It is effectively a compile-time constant.
1476
1477- A warning will be issued if a global statement for a variable
1478 follows a use or assignment of that variable.
1479
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001480Standard library
1481
Guido van Rossum053ae352001-03-22 14:17:21 +00001482- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1483 inspired by JUnit), is now part of the standard library. You now
1484 have a choice of two testing frameworks: unittest requires you to
1485 write testcases as separate code, doctest gathers them from
1486 docstrings. Both approaches have their advantages and
1487 disadvantages.
1488
1489- A new module Tix was added, which wraps the Tix extension library
1490 for Tk. With that module, it is not necessary to statically link
1491 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1492 require" command. See Demo/tix/.
1493
1494- tzparse.py is now obsolete.
1495
1496- In gzip.py, the seek() and tell() methods are removed -- they were
1497 non-functional anyway, and it's better if callers can test for their
1498 existence with hasattr().
1499
1500Python/C API
1501
1502- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1503 that's already in the dictionary during a PyDict_Next() iteration.
1504 This used to fail occasionally when a dictionary resize operation
1505 could be triggered that would rehash all the keys. All other
1506 modifications to the dictionary are still off-limits during a
1507 PyDict_Next() iteration!
1508
1509- New extended APIs related to passing compiler variables around.
1510
1511- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1512 implement isinstance() and issubclass().
1513
1514- Py_BuildValue() now has a "D" conversion to create a Python complex
1515 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001516
Fred Drake4e262a92001-03-22 18:26:47 +00001517- Extensions types which support weak references must now set the
1518 field allocated for the weak reference machinery to NULL themselves;
1519 this is done to avoid the cost of checking each object for having a
1520 weakly referencable type in PyObject_INIT(), since most types are
1521 not weakly referencable.
1522
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001523- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1524 free variables and cell variables to and from the frame's f_locals.
1525
1526- Variants of several functions defined in pythonrun.h have been added
1527 to support the nested_scopes future statement. The variants all end
1528 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1529 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1530 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001531 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001532
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001533Distutils
1534
1535- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1536 into the release tree.
1537
Tim Peters0e57abf2001-05-02 07:39:38 +00001538- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001539 (an uninstaller, more customization of the installer's display)
1540
1541- from Jack Jansen: added Mac-specific code to generate a dialog for
1542 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001543 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001544 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001545
1546- added 'platforms' and 'keywords' to the set of metadata that can be
1547 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001548
1549- applied patches from Jason Tishler to make the compiler class work with
1550 Cygwin.
1551
1552
Tim Peters2fe289a2001-03-01 22:19:38 +00001553What's New in Python 2.1 beta 1?
1554================================
Tim Petersd66595f2001-02-04 03:09:53 +00001555
1556Core language, builtins, and interpreter
1557
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001558- Following an outcry from the community about the amount of code
1559 broken by the nested scopes feature introduced in 2.1a2, we decided
1560 to make this feature optional, and to wait until Python 2.2 (or at
1561 least 6 months) to make it standard. The option can be enabled on a
1562 per-module basis by adding "from __future__ import nested_scopes" at
1563 the beginning of a module (before any other statements, but after
1564 comments and an optional docstring). See PEP 236 (Back to the
1565 __future__) for a description of the __future__ statement. PEP 227
1566 (Statically Nested Scopes) has been updated to reflect this change,
1567 and to clarify the semantics in a number of endcases.
1568
1569- The nested scopes code, when enabled, has been hardened, and most
1570 bugs and memory leaks in it have been fixed.
1571
1572- Compile-time warnings are now generated for a number of conditions
1573 that will break or change in meaning when nested scopes are enabled:
1574
1575 - Using "from...import *" or "exec" without in-clause in a function
1576 scope that also defines a lambda or nested function with one or
1577 more free (non-local) variables. The presence of the import* or
1578 bare exec makes it impossible for the compiler to determine the
1579 exact set of local variables in the outer scope, which makes it
1580 impossible to determine the bindings for free variables in the
1581 inner scope. To avoid the warning about import *, change it into
1582 an import of explicitly name object, or move the import* statement
1583 to the global scope; to avoid the warning about bare exec, use
1584 exec...in... (a good idea anyway -- there's a possibility that
1585 bare exec will be deprecated in the future).
1586
1587 - Use of a global variable in a nested scope with the same name as a
1588 local variable in a surrounding scope. This will change in
1589 meaning with nested scopes: the name in the inner scope will
1590 reference the variable in the outer scope rather than the global
1591 of the same name. To avoid the warning, either rename the outer
1592 variable, or use a global statement in the inner function.
1593
Neil Schemenauera35c6882001-02-27 04:45:05 +00001594- An optional object allocator has been included. This allocator is
1595 optimized for Python objects and should be faster and use less memory
1596 than the standard system allocator. It is not enabled by default
1597 because of possible thread safety problems. The allocator is only
1598 protected by the Python interpreter lock and it is possible that some
1599 extension modules require a thread safe allocator. The object
1600 allocator can be enabled by providing the "--with-pymalloc" option to
1601 configure.
1602
Tim Petersd66595f2001-02-04 03:09:53 +00001603Standard library
1604
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001605- pyexpat now detects the expat version if expat.h defines it. A
1606 number of additional handlers are provided, which are only available
1607 since expat 1.95. In addition, the methods SetParamEntityParsing and
1608 GetInputContext of Parser objects are available with 1.95.x
1609 only. Parser objects now provide the ordered_attributes and
1610 specified_attributes attributes. A new module expat.model was added,
1611 which offers a number of additional constants if 1.95.x is used.
1612
1613- xml.dom offers the new functions registerDOMImplementation and
1614 getDOMImplementation.
1615
1616- xml.dom.minidom offers a toprettyxml method. A number of DOM
1617 conformance issues have been resolved. In particular, Element now
1618 has an hasAttributes method, and the handling of namespaces was
1619 improved.
1620
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001621- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1622 getting information about live Python code, and pydoc.py, a module
1623 for interactively converting docstrings to HTML or text.
1624 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001625 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001626 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1627 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001628
Tim Peters1eff7962001-03-01 02:31:33 +00001629- New library module difflib.py, primarily packaging the SequenceMatcher
1630 class at the heart of the popular ndiff.py file-comparison tool.
1631
1632- doctest.py (a framework for verifying Python code examples in docstrings)
1633 is now part of the std library.
1634
Tim Petersd66595f2001-02-04 03:09:53 +00001635Windows changes
1636
Guido van Rossume3955a82001-03-02 14:05:59 +00001637- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1638 small GUI that lets you browse the module docstrings using your
1639 default web browser.
1640
Tim Peters1eff7962001-03-01 02:31:33 +00001641- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1642 Platforms) is implemented. See
1643
1644 http://python.sourceforge.net/peps/pep-0235.html
1645
1646 for full details, especially the "Current Lower-Left Semantics" section.
1647 The new Windows import rules are simpler than before:
1648
1649 A. If the PYTHONCASEOK environment variable exists, same as
1650 before: silently accept the first case-insensitive match of any
1651 kind; raise ImportError if none found.
1652
1653 B. Else search sys.path for the first case-sensitive match; raise
1654 ImportError if none found.
1655
1656 The same rules have been implented on other platforms with case-
1657 insensitive but case-preserving filesystems too (including Cygwin, and
1658 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001659
Tim Peters25a9ce32001-02-19 07:06:36 +00001660- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1661 what it's supposed to do (and does do under NT and 2000) via direct
1662 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001663 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001664 all Win9x systems before.
1665
Tim Peters1eff7962001-03-01 02:31:33 +00001666- Build: Subproject _test (effectively) renamed to _testcapi.
1667
Tim Peters2fe289a2001-03-01 22:19:38 +00001668New platforms
1669
1670- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1671 Thanks to Steven Majewski!
1672
1673- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1674 Tishler!
1675
Guido van Rossum9089b272001-03-02 06:49:50 +00001676- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1677 Schwertberger! See RISCOS/README for more information -- it seems
1678 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001679 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001680
Tim Peters25a9ce32001-02-19 07:06:36 +00001681
Tim Petersd7b5e882001-01-25 03:36:26 +00001682What's New in Python 2.1 alpha 2?
1683=================================
Tim Peters40ead762001-01-27 05:35:26 +00001684
Tim Petersd7b5e882001-01-25 03:36:26 +00001685Core language, builtins, and interpreter
1686
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001687- Scopes nest. If a name is used in a function or class, but is not
1688 local, the definition in the nearest enclosing function scope will
1689 be used. One consequence of this change is that lambda statements
1690 could reference variables in the namespaces where the lambda is
1691 defined. In some unusual cases, this change will break code.
1692
1693 In all previous version of Python, names were resolved in exactly
1694 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001695 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001696 function A is defined within a function B, the names bound in B are
1697 not visible in A. The new rules make names bound in B visible in A,
1698 unless A contains a name binding that hides the binding in B.
1699
1700 Section 4.1 of the reference manual describes the new scoping rules
1701 in detail. The test script in Lib/test/test_scope.py demonstrates
1702 some of the effects of the change.
1703
1704 The new rules will cause existing code to break if it defines nested
1705 functions where an outer function has local variables with the same
1706 name as globals or builtins used by the inner function. Example:
1707
1708 def munge(str):
1709 def helper(x):
1710 return str(x)
1711 if type(str) != type(''):
1712 str = helper(str)
1713 return str.strip()
1714
1715 Under the old rules, the name str in helper() is bound to the
1716 builtin function str(). Under the new rules, it will be bound to
1717 the argument named str and an error will occur when helper() is
1718 called.
1719
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001720- The compiler will report a SyntaxError if "from ... import *" occurs
1721 in a function or class scope. The language reference has documented
1722 that this case is illegal, but the compiler never checked for it.
1723 The recent introduction of nested scope makes the meaning of this
1724 form of name binding ambiguous. In a future release, the compiler
1725 may allow this form when there is no possibility of ambiguity.
1726
Tim Peters40ead762001-01-27 05:35:26 +00001727- repr(string) is easier to read, now using hex escapes instead of octal,
1728 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1729
1730 >>> "\texample \r\n" + chr(0) + chr(255)
1731 '\texample \r\n\x00\xff' # in 2.1
1732 '\011example \015\012\000\377' # in 2.0
1733
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001734- Functions are now compared and hashed by identity, not by value, since
1735 the func_code attribute is writable.
1736
Fred Drakefb9d7122001-02-01 20:00:40 +00001737- Weak references (PEP 205) have been added. This involves a few
1738 changes in the core, an extension module (_weakref), and a Python
1739 module (weakref). The weakref module is the public interface. It
1740 includes support for "explicit" weak references, proxy objects, and
1741 mappings with weakly held values.
1742
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001743- A 'continue' statement can now appear in a try block within the body
1744 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001745 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001746
Tim Petersd7b5e882001-01-25 03:36:26 +00001747Standard library
1748
Barry Warsaw30dbd142001-01-31 22:14:01 +00001749- mailbox.py now has a new class, PortableUnixMailbox which is
1750 identical to UnixMailbox but uses a more portable scheme for
1751 determining From_ separators. Also, the constructors for all the
1752 classes in this module have a new optional `factory' argument, which
1753 is a callable used when new message classes must be instantiated by
1754 the next() method.
1755
Tim Petersd7b5e882001-01-25 03:36:26 +00001756- random.py is now self-contained, and offers all the functionality of
1757 the now-deprecated whrandom.py. See the docs for details. random.py
1758 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001759 and restoring the internal state of the generator; and jumpahead(n),
1760 for quickly forcing the internal state to be the same as if n calls to
1761 random() had been made. The latter is particularly useful for multi-
1762 threaded programs, creating one instance of the random.Random() class for
1763 each thread, then using .jumpahead() to force each instance to use a
1764 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001765
Tim Peters0de88fc2001-02-01 04:59:18 +00001766- random.py's seed() function is new. For bit-for-bit compatibility with
1767 prior releases, use the whseed function instead. The new seed function
1768 addresses two problems: (1) The old function couldn't produce more than
1769 about 2**24 distinct internal states; the new one about 2**45 (the best
1770 that can be done in the Wichmann-Hill generator). (2) The old function
1771 sometimes produced identical internal states when passed distinct
1772 integers, and there was no simple way to predict when that would happen;
1773 the new one guarantees to produce distinct internal states for all
1774 arguments in [0, 27814431486576L).
1775
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001776- The socket module now supports raw packets on Linux. The socket
1777 family is AF_PACKET.
1778
Tim Peters9ea17ac2001-02-02 05:57:15 +00001779- test_capi.py is a start at running tests of the Python C API. The tests
1780 are implemented by the new Modules/_testmodule.c.
1781
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001782- A new extension module, _symtable, provides provisional access to the
1783 internal symbol table used by the Python compiler. A higher-level
1784 interface will be added on top of _symtable in a future release.
1785
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001786- Removed the obsolete soundex module.
1787
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001788- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1789 the isSameNode method; NamedNodeMap the get method.
1790
1791- xml.sax.expatreader supports the lexical handler property; it
1792 generates comment, startCDATA, and endCDATA events.
1793
Tim Petersee826f82001-01-31 19:39:44 +00001794Windows changes
1795
1796- Build procedure: the zlib project is built in a different way that
1797 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001798 the zlib binary used. See PCbuild\readme.txt for details. Your old
1799 zlib-related directories can be deleted; you'll need to download fresh
1800 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001801
Tim Peters9ea17ac2001-02-02 05:57:15 +00001802- Build: New subproject _test for the benefit of test_capi.py (see above).
1803
Tim Petersb16c56f2001-02-02 21:24:51 +00001804- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1805 interface to some Python compiler internals).
1806
1807- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001808 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001809
Tim Petersa3a3a032000-11-30 05:22:44 +00001810What's New in Python 2.1 alpha 1?
1811=================================
1812
1813Core language, builtins, and interpreter
1814
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001815- There is a new Unicode companion to the PyObject_Str() API
1816 called PyObject_Unicode(). It behaves in the same way as the
1817 former, but assures that the returned value is an Unicode object
1818 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001819
Guido van Rossumf98eda02001-01-17 15:54:45 +00001820- The comparison operators support "rich comparison overloading" (PEP
1821 207). C extension types can provide a rich comparison function in
1822 the new tp_richcompare slot in the type object. The cmp() function
1823 and the C function PyObject_Compare() first try the new rich
1824 comparison operators before trying the old 3-way comparison. There
1825 is also a new C API PyObject_RichCompare() (which also falls back on
1826 the old 3-way comparison, but does not constrain the outcome of the
1827 rich comparison to a Boolean result).
1828
1829 The rich comparison function takes two objects (at least one of
1830 which is guaranteed to have the type that provided the function) and
1831 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1832 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1833 object, which may be NotImplemented (in which case the tp_compare
1834 slot function is used as a fallback, if defined).
1835
1836 Classes can overload individual comparison operators by defining one
1837 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001838 __ge__. There are no explicit "reflected argument" versions of
1839 these; instead, __lt__ and __gt__ are each other's reflection,
1840 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1841 reflection (similar at the C level). No other implications are
1842 made; in particular, Python does not assume that == is the Boolean
1843 inverse of !=, or that < is the Boolean inverse of >=. This makes
1844 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001845
1846 Classes or types that want to implement (in)equality tests but not
1847 the ordering operators (i.e. unordered types) should implement ==
1848 and !=, and raise an error for the ordering operators.
1849
Guido van Rossuma88479f2001-01-18 14:28:08 +00001850 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001851 Boolean; e.g. a matrix type might want to return a matrix of bits
1852 for A < B, giving elementwise comparisons. Such types should ensure
1853 that any interpretation of their value in a Boolean context raises
1854 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1855 at the C level) to always raise an exception.
1856
Guido van Rossuma88479f2001-01-18 14:28:08 +00001857- Complex numbers use rich comparisons to define == and != but raise
1858 an exception for <, <=, > and >=. Unfortunately, this also means
1859 that cmp() of two complex numbers raises an exception when the two
1860 numbers differ. Since it is not mathematically meaningful to compare
1861 complex numbers except for equality, I hope that this doesn't break
1862 too much code.
1863
Tim Peters3389f192001-02-18 08:48:49 +00001864- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001865 not defined by the language, other than that it's arbitrary but
1866 consistent (see the Reference Manual). An implementation detail changed
1867 in 2.1a1 such that None now compares less than any other object. Code
1868 relying on this new behavior (like code that relied on the previous
1869 behavior) does so at its own risk.
1870
Barry Warsaw573b5412001-01-15 20:43:18 +00001871- Functions and methods now support getting and setting arbitrarily
1872 named attributes (PEP 232). Functions have a new __dict__
1873 (a.k.a. func_dict) which hold the function attributes. Methods get
1874 and set attributes on their underlying im_func. It is a TypeError
1875 to set an attribute on a bound method.
1876
Guido van Rossum051e3352001-01-15 19:11:10 +00001877- The xrange() object implementation has been improved so that
1878 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1879 limitation that in this case len(xrange(sys.maxint)) can't be
1880 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1881 work fine as long as the index i doesn't actually reach 2**31.
1882 (Python uses regular ints for sequence and string indices; fixing
1883 that is much more work.)
1884
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001885- Two changes to from...import:
1886
Guido van Rossumba381232001-02-03 15:06:40 +00001887 1) "from M import X" now works even if (after loading module M)
1888 sys.modules['M'] is not a real module; it's basically a getattr()
1889 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001890
1891 2) "from M import *" now looks for M.__all__ to decide which names to
1892 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1893 filters out names starting with '_' as before. Whether or not
1894 __all__ exists, there's no restriction on the type of M.
1895
Guido van Rossumf61f1662001-01-10 20:13:55 +00001896- File objects have a new method, xreadlines(). This is the fastest
1897 way to iterate over all lines in a file:
1898
1899 for line in file.xreadlines():
1900 ...do something to line...
1901
1902 See the xreadlines module (mentioned below) for how to do this for
1903 other file-like objects.
1904
1905- Even if you don't use file.xreadlines(), you may expect a speedup on
1906 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001907 quite a bit in platform-specific ways: on systems (like Linux) that
1908 support flockfile(), getc_unlocked(), and funlockfile(), those are
1909 used by default. On systems (like Windows) without getc_unlocked(),
1910 a complicated (but still thread-safe) method using fgets() is used by
1911 default.
1912
Tim Petersd52269b2001-01-25 06:23:18 +00001913 You can force use of the fgets() method by #define'ing
1914 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001915 getc_unlocked()).
1916
Tim Petersd52269b2001-01-25 06:23:18 +00001917 You can force fgets() not to be used by #define'ing
1918 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001919 test_bufio.py fails -- and let us know if it does!).
1920
1921- In addition, the fileinput module, while still slower than the other
1922 methods on most platforms, has been sped up too, by using
1923 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001924
1925- Support for run-time warnings has been added, including a new
1926 command line option (-W) to specify the disposition of warnings.
1927 See the description of the warnings module below.
1928
1929- Extensive changes have been made to the coercion code. This mostly
1930 affects extension modules (which can now implement mixed-type
1931 numerical operators without having to use coercion), but
1932 occasionally, in boundary cases the coercion semantics have changed
1933 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001934 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001935 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001936 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001937
Guido van Rossumf98eda02001-01-17 15:54:45 +00001938- In connection with the coercion changes, a new built-in singleton
1939 object, NotImplemented is defined. This can be returned for
1940 operations that wish to indicate they are not implemented for a
1941 particular combination of arguments. From C, this is
1942 Py_NotImplemented.
1943
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001944- The interpreter accepts now bytecode files on the command line even
1945 if they do not have a .pyc or .pyo extension. On Linux, after executing
1946
Martin v. Löwise214baa2001-02-04 22:37:56 +00001947import imp,sys,string
1948magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1949reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1950open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001951
1952 any byte code file can be used as an executable (i.e. as an argument
1953 to execve(2)).
1954
Tim Peters9940b802000-12-01 07:59:35 +00001955- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001956 character. In 1.6 and earlier, they never produced a sign,
1957 and raised an error if the value of the long was too large
1958 to fit in a Python int. In 2.0, they produced a sign if and
1959 only if too large to fit in an int. This was inconsistent
1960 across platforms (because the size of an int varies across
1961 platforms), and inconsistent with hex() and oct(). Example:
1962
1963 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001964 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001965 'ffffffbe' # in 2.0 and before, on 32-bit machines
1966 >>> hex(-0x42L)
1967 '-0x42L' # in all versions of Python
1968
Tim Peters9940b802000-12-01 07:59:35 +00001969 The behavior of %d formats for negative Python longs remains
1970 the same as in 2.0 (although in 1.6 and before, they raised
1971 an error if the long didn't fit in a Python int).
1972
1973 %u formats don't make sense for Python longs, but are allowed
1974 and treated the same as %d in 2.1. In 2.0, a negative long
1975 formatted via %u produced a sign if and only if too large to
1976 fit in an int. In 1.6 and earlier, a negative long formatted
1977 via %u raised an error if it was too big to fit in an int.
1978
Guido van Rossum3661d392000-12-12 22:10:31 +00001979- Dictionary objects have an odd new method, popitem(). This removes
1980 an arbitrary item from the dictionary and returns it (in the form of
1981 a (key, value) pair). This can be useful for algorithms that use a
1982 dictionary as a bag of "to do" items and repeatedly need to pick one
1983 item. Such algorithms normally end up running in quadratic time;
1984 using popitem() they can usually be made to run in linear time.
1985
Tim Peters36cdad12000-12-29 02:06:45 +00001986Standard library
1987
Thomas Woutersfe385252001-01-19 23:16:56 +00001988- In the time module, the time argument to the functions strftime,
1989 localtime, gmtime, asctime and ctime is now optional, defaulting to
1990 the current time (in the local timezone).
1991
Guido van Rossumda91f222001-01-15 16:36:08 +00001992- The ftplib module now defaults to passive mode, which is deemed a
1993 more useful default given that clients are often inside firewalls
1994 these days. Note that this could break if ftplib is used to connect
1995 to a *server* that is inside a firewall, from outside; this is
1996 expected to be a very rare situation. To fix that, you can call
1997 ftp.set_pasv(0).
1998
Martin v. Löwis10a27872001-01-13 09:54:41 +00001999- The module site now treats .pth files not only for path configuration,
2000 but also supports extensions to the initialization code: Lines starting
2001 with import are executed.
2002
Guido van Rossumf61f1662001-01-10 20:13:55 +00002003- There's a new module, warnings, which implements a mechanism for
2004 issuing and filtering warnings. There are some new built-in
2005 exceptions that serve as warning categories, and a new command line
2006 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2007 turns warnings into errors). warnings.warn(message[, category])
2008 issues a warning message; this can also be called from C as
2009 PyErr_Warn(category, message).
2010
2011- A new module xreadlines was added. This exports a single factory
2012 function, xreadlines(). The intention is that this code is the
2013 absolutely fastest way to iterate over all lines in an open
2014 file(-like) object:
2015
2016 import xreadlines
2017 for line in xreadlines.xreadlines(file):
2018 ...do something to line...
2019
2020 This is equivalent to the previous the speed record holder using
2021 file.readlines(sizehint). Note that if file is a real file object
2022 (as opposed to a file-like object), this is equivalent:
2023
2024 for line in file.xreadlines():
2025 ...do something to line...
2026
Tim Peters36cdad12000-12-29 02:06:45 +00002027- The bisect module has new functions bisect_left, insort_left,
2028 bisect_right and insort_right. The old names bisect and insort
2029 are now aliases for bisect_right and insort_right. XXX_right
2030 and XXX_left methods differ in what happens when the new element
2031 compares equal to one or more elements already in the list: the
2032 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002033 right. Code that doesn't care where equal elements end up should
2034 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002035
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002036- The new curses.panel module wraps the panel library that forms part
2037 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2038
Guido van Rossumf61f1662001-01-10 20:13:55 +00002039- The SocketServer module now sets the allow_reuse_address flag by
2040 default in the TCPServer class.
2041
2042- A new function, sys._getframe(), returns the stack frame pointer of
2043 the caller. This is intended only as a building block for
2044 higher-level mechanisms such as string interpolation.
2045
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002046- The pyexpat module supports a number of new handlers, which are
2047 available only in expat 1.2. If invocation of a callback fails, it
2048 will report an additional frame in the traceback. Parser objects
2049 participate now in garbage collection. If expat reports an unknown
2050 encoding, pyexpat will try to use a Python codec; that works only
2051 for single-byte charsets. The parser type objects is exposed as
2052 XMLParserObject.
2053
2054- xml.dom now offers standard definitions for symbolic node type and
2055 exception code constants, and a hierarchy of DOM exceptions. minidom
2056 was adjusted to use them.
2057
2058- The conformance of xml.dom.minidom to the DOM specification was
2059 improved. It detects a number of additional error cases; the
2060 previous/next relationship works even when the tree is modified;
2061 Node supports the normalize() method; NamedNodeMap, DocumentType and
2062 DOMImplementation classes were added; Element supports the
2063 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2064 method.
2065
Guido van Rossumf61f1662001-01-10 20:13:55 +00002066Build issues
2067
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002068- For Unix (and Unix-compatible) builds, configuration and building of
2069 extension modules is now greatly automated. Rather than having to
2070 edit the Modules/Setup file to indicate which modules should be
2071 built and where their include files and libraries are, a
2072 distutils-based setup.py script now takes care of building most
2073 extension modules. All extension modules built this way are built
2074 as shared libraries. Only a few modules that must be linked
2075 statically are still listed in the Setup file; you won't need to
2076 edit their configuration.
2077
2078- Python should now build out of the box on Cygwin. If it doesn't,
2079 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002080
2081- Python now always uses its own (renamed) implementation of getopt()
2082 -- there's too much variation among C library getopt()
2083 implementations.
2084
2085- C++ compilers are better supported; the CXX macro is always set to a
2086 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002087
Tim Petersd92dfe02000-12-12 01:18:41 +00002088Windows changes
2089
2090- select module: By default under Windows, a select() call
2091 can specify no more than 64 sockets. Python now boosts
2092 this Microsoft default to 512. If you need even more than
2093 that, see the MS docs (you'll need to #define FD_SETSIZE
2094 and recompile Python from source).
2095
Guido van Rossumf61f1662001-01-10 20:13:55 +00002096- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2097 subdirectory is no more!
2098
Tim Petersa3a3a032000-11-30 05:22:44 +00002099
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002100What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002101=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002102
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002103Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002104changes are in the file HISTORY. If you are making the jump directly
2105from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2106HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002107
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002108Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2109the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2110http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002111
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002112--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002113
2114======================================================================
2115
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002116What's new in 2.0 (since release candidate 1)?
2117==============================================
2118
2119Standard library
2120
2121- The copy_reg module was modified to clarify its intended use: to
2122 register pickle support for extension types, not for classes.
2123 pickle() will raise a TypeError if it is passed a class.
2124
2125- Fixed a bug in gettext's "normalize and expand" code that prevented
2126 it from finding an existing .mo file.
2127
2128- Restored support for HTTP/0.9 servers in httplib.
2129
Tim Peters989b7b92000-10-16 20:24:53 +00002130- The math module was changed to stop raising OverflowError in case of
2131 underflow, and return 0 instead in underflow cases. Whether Python
2132 used to raise OverflowError in case of underflow was platform-
2133 dependent (it did when the platform math library set errno to ERANGE
2134 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002135
2136- Fixed a bug in StringIO that occurred when the file position was not
2137 at the end of the file and write() was called with enough data to
2138 extend past the end of the file.
2139
2140- Fixed a bug that caused Tkinter error messages to get lost on
2141 Windows. The bug was fixed by replacing direct use of
2142 interp->result with Tcl_GetStringResult(interp).
2143
2144- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2145 redirect response.
2146
2147- Several changes were made to distutils: Some debugging code was
2148 removed from util. Fixed the installer used when an external zip
2149 program (like WinZip) is not found; the source code for this
2150 installer is in Misc/distutils. check_lib() was modified to behave
2151 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2152 test for whether installed modules are on sys.path was changed to
2153 use both normcase() and normpath().
2154
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002155- Several minor bugs were fixed in the xml package (the minidom,
2156 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002157
2158- The regression test driver (regrtest.py) behavior when invoked with
2159 -l changed: It now reports a count of objects that are recognized as
2160 garbage but not freed by the garbage collector.
2161
Tim Peters989b7b92000-10-16 20:24:53 +00002162- The regression test for the math module was changed to test
2163 exceptional behavior when the test is run in verbose mode. Python
2164 cannot yet guarantee consistent exception behavior across platforms,
2165 so the exception part of test_math is run only in verbose mode, and
2166 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002167
2168Internals
2169
2170- PyOS_CheckStack() has been disabled on Win64, where it caused
2171 test_sre to fail.
2172
2173Build issues
2174
2175- Changed compiler flags, so that gcc is always invoked with -Wall and
2176 -Wstrict-prototypes. Users compiling Python with GCC should see
2177 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002178 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002179 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002180
Tim Petersa3a3a032000-11-30 05:22:44 +00002181- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002182
2183Tools and other miscellany
2184
2185- The compiler in Tools/compiler was updated to support the new
2186 language features introduced in 2.0: extended print statement, list
2187 comprehensions, and augmented assignments. The new compiler should
2188 also be backwards compatible with Python 1.5.2; the compiler will
2189 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002190 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002191
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002192What's new in 2.0 release candidate 1 (since beta 2)?
2193=====================================================
2194
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002195What is release candidate 1?
2196
2197We believe that release candidate 1 will fix all known bugs that we
2198intend to fix for the 2.0 final release. This release should be a bit
2199more stable than the previous betas. We would like to see even more
2200widespread testing before the final release, so we are producing this
2201release candidate. The final release will be exactly the same unless
2202any show-stopping (or brown bag) bugs are found by testers of the
2203release candidate.
2204
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002205All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002206to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002207
2208Core language, builtins, and interpreter
2209
2210- A bug that caused crashes when __coerce__ was used with augmented
2211 assignment, e.g. +=, was fixed.
2212
2213- Raise ZeroDivisionError when raising zero to a negative number,
2214 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2215 power operator and the result of math.pow(0.0, -2.0) will vary by
2216 platform. On Linux, it raises a ValueError.
2217
2218- A bug in Unicode string interpolation was fixed that occasionally
2219 caused errors with formats including "%%". For example, the
2220 following expression "%% %s" % u"abc" no longer raises a TypeError.
2221
2222- Compilation of deeply nested expressions raises MemoryError instead
2223 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2224
2225- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2226 rendering them useless. They are now written in binary mode again.
2227
2228Standard library
2229
2230- Keyword arguments are now accepted for most pattern and match object
2231 methods in SRE, the standard regular expression engine.
2232
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002233- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002234 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002235
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002236- Several bugs in the Unicode handling and error handling in _tkinter
2237 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002238
2239- Fix memory management errors in Merge() and Tkapp_Call() routines.
2240
2241- Several changes were made to cStringIO to make it compatible with
2242 the file-like object interface and with StringIO. If operations are
2243 performed on a closed object, an exception is raised. The truncate
2244 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002245 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002246
2247- There were many changes made to the linuxaudiodev module and its
2248 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002249 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002250
2251 Note that this module is named poorly, because it should work
2252 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002253 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002254
2255 The module now raises exceptions when errors occur instead of
2256 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2257 audio) and defines a getptr() method that calls the
2258 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2259
2260- The library_version attribute, introduced in an earlier beta, was
2261 removed because it can not be supported with early versions of the C
2262 readline library, which provides no way to determine the version at
2263 compile-time.
2264
2265- The binascii module is now enabled on Win64.
2266
Tim Peters46446d62000-10-09 21:19:31 +00002267- tokenize.py no longer suffers "recursion depth" errors when parsing
2268 programs with very long string literals.
2269
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002270Internals
2271
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002272- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002273 which is called when the interpreter starts up to determine where
2274 the standard library is installed. These vulnerabilities affect all
2275 previous versions of Python and can be exploited by setting very
2276 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2277 setuid Python script, although use of the wrapper in
2278 Misc/setuid-prog.c will eliminate the vulnerability.
2279
2280- Fixed garbage collection bugs in instance creation that were
2281 triggered when errors occurred during initialization. The solution,
2282 applied in cPickle and in PyInstance_New(), is to call
2283 PyObject_GC_Init() after the initialization of the object's
2284 container attributes is complete.
2285
2286- pyexpat adds definitions of PyModule_AddStringConstant and
2287 PyModule_AddObject if the Python version is less than 2.0, which
2288 provides compatibility with PyXML on Python 1.5.2.
2289
2290- If the platform has a bogus definition for LONG_BIT (the number of
2291 bits in a long), an error will be reported at compile time.
2292
2293- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2294 collection crashes and possibly other, unreported crashes.
2295
2296- Fixed a memory leak in _PyUnicode_Fini().
2297
2298Build issues
2299
2300- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002301 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002302 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002303
2304- The mmap.PAGESIZE constant is now initialized using sysconf when
2305 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2306
2307- The md5 file should now compile on all platforms.
2308
2309- The select module now compiles on platforms that do not define
2310 POLLRDNORM and related constants.
2311
2312- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002313 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002314
Jeremy Hylton10921202000-10-09 18:34:12 +00002315- BeOS: A number of changes were made to the build and installation
2316 process. ar-fake now operates on a directory of object files.
2317 dl_export.h is gone, and its macros now appear on the mwcc command
2318 line during build on PPC BeOS.
2319
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002320- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002321 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002322
2323- Cygwin: Support for shared libraries, Tkinter, and sockets.
2324
2325- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2326
2327Tools and other miscellany
2328
2329- Removed debugging prints from main used with freeze.
2330
Tim Peters46446d62000-10-09 21:19:31 +00002331- IDLE auto-indent no longer crashes when it encounters Unicode
2332 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002333
2334What's new in 2.0 beta 2 (since beta 1)?
2335========================================
2336
2337Core language, builtins, and interpreter
2338
Tim Peters482c0212000-09-26 06:33:09 +00002339- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002340 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002341
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002342- Add -h and -V command line options to print the usage message and
2343 Python version number and exit immediately.
2344
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002345- eval() and exec accept Unicode objects as code parameters.
2346
2347- getattr() and setattr() now also accept Unicode objects for the
2348 attribute name, which are converted to strings using the default
2349 encoding before lookup.
2350
2351- Multiplication on string and Unicode now does proper bounds
2352 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2353 string is too long."
2354
2355- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002356 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002357
Jeremy Hylton1b618592000-09-26 05:32:36 +00002358
2359Standard library and extensions
2360
Guido van Rossum5b08f132001-04-16 02:05:23 +00002361- socket module: the OpenSSL code now adds support for RAND_status()
2362 and EGD (Entropy Gathering Device).
2363
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002364- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002365 argument checking; it still takes no arguments.
2366
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002367- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002368
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002369- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002370
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002371- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002372
2373- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002374 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002375
2376- copy: Copy Unicode objects atomically.
2377
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002378- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002379
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002380- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002381
Fred Drake67233bc2000-09-26 16:40:27 +00002382- dbm: Add get() and setdefault() methods to dbm object. Add constant
2383 `library' to module that names the library used. Added doc strings
2384 and method names to error messages. Uses configure to determine
2385 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2386 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002387
2388- distutils: Update to version 0.9.3.
2389
2390- dl: Add several dl.RTLD_ constants.
2391
2392- fpectl: Now supported on FreeBSD.
2393
2394- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2395 found by the collector will be saved in gc.garbage. This is useful
2396 for debugging a program that creates reference cycles.
2397
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002398- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002399 of HTTP class. Do not close socket on zero-length response. Do not
2400 crash when server sends invalid content-length header.
2401
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002402- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002403
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002404- marshal: When reading a short, sign-extend on platforms where shorts
2405 are bigger than 16 bits. When reading a long, repair the unportable
2406 sign extension that was being done for 64-bit machines. (It assumed
2407 that signed right shift sign-extends.)
2408
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002409- operator: Add contains(), invert(), __invert__() as aliases for
2410 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002411
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002412- os: Add support for popen2() and popen3() on all platforms where
2413 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002414
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002415- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002416 clicking on a file in Explorer (or passing the file name to the
2417 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002418
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002419- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002420 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002421
2422- pickle: Now raises ValueError when an invalid pickle that contains
2423 a non-string repr where a string repr was expected. This behavior
2424 matches cPickle.
2425
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002426- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002427
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002428- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002429
2430- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002431 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002432 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002433
2434- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002435 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002436
2437- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002438 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002439 few cycles during startup since the first call to
2440 setdefaultencoding() will initialize the codec registry and the
2441 encodings package.
2442
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002443- socket: Support for size hint in readlines() method of object returned
2444 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002445
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002446- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002447 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002448 is followed by whitespace.
2449
Tim Petersa3a3a032000-11-30 05:22:44 +00002450- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002451
2452- struct: Check ranges for bytes and shorts.
2453
2454- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002455 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002456
2457- Tkinter: Image objects are now guaranteed to have unique ids. Set
2458 event.delta to zero if Tk version doesn't support mousewheel.
2459 Removed some debugging prints.
2460
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002461- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002462
Fred Drake67233bc2000-09-26 16:40:27 +00002463- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002464 which works around a bug in Norton AntiVirus 2000 that leads directly
2465 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002466
2467- xml: New version detection code allows PyXML to override standard
2468 XML package if PyXML version is greater than 0.6.1.
2469
Fred Drake64bb3802000-09-26 16:21:35 +00002470- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2471 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2472 tree only for nodes which are sufficiently interesting to a specific
2473 application. Does not provide the HTML-specific extensions. Still
2474 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002475
Fred Drake64bb3802000-09-26 16:21:35 +00002476- xml.sax: SAX 2 support for Python, including all the handler
2477 interfaces needed to process XML 1.0 compliant XML. Some
2478 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002479
Fred Drake64bb3802000-09-26 16:21:35 +00002480- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2481 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002482
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002483
Jeremy Hylton1b618592000-09-26 05:32:36 +00002484C API
2485
2486- Add three new convenience functions for module initialization --
2487 PyModule_AddObject(), PyModule_AddIntConstant(), and
2488 PyModule_AddStringConstant().
2489
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002490- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002491 removed and add #error to Python.h if NULL isn't defined after
2492 #include of stdio.h.
2493
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002494- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002495 backwards compatibility (at the source level) with old extensions.
2496
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002497- A wrapper API was added for signal() and sigaction(). Instead of
2498 either function, always use PyOS_getsig() to get a signal handler
2499 and PyOS_setsig() to set one. A new convenience typedef
2500 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002501
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002502- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002503 internal data buffer and size of a string object -- or the default
2504 encoded version of a Unicode object.
2505
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002506- PyString_Size() and PyString_AsString() accept Unicode objects.
2507
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002508- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002509 exists). INT_MAX and LONG_MAX will always be defined, even if
2510 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002511
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002512- PyFloat_FromString takes a second argument, pend, that was
2513 effectively useless. It is now officially useless but preserved for
2514 backwards compatibility. If the pend argument is not NULL, *pend is
2515 set to NULL.
2516
2517- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2518 for the attribute name. See note on getattr() above.
2519
2520- A few bug fixes to argument processing for Unicode.
2521 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2522 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2523 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002524 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002525
2526- Py_BuildValue accepts B format (for bgen-generated code).
2527
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002528
Jeremy Hylton1b618592000-09-26 05:32:36 +00002529Internals
2530
2531- On Unix, fix code for finding Python installation directory so that
2532 it works when argv[0] is a relative path.
2533
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002534- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002535 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002536 rather than by generating a copy of the object.
2537
Tim Peters482c0212000-09-26 06:33:09 +00002538- Several of the internal Unicode tables are much smaller now, and
2539 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002540
Jeremy Hylton97693b02000-09-26 17:42:51 +00002541- In the garbage collector: Fixed bug in collection of tuples. Fixed
2542 bug that caused some instances to be removed from the container set
2543 while they were still live. Fixed parsing in gc.set_debug() for
2544 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002545
2546- Fixed refcount problem in instance deallocation that only occurred
2547 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2548
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002549- On Windows, getpythonregpath is now protected against null data in
2550 registry key.
2551
2552- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002553 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002554
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002555
Jeremy Hylton1b618592000-09-26 05:32:36 +00002556Build and platform-specific issues
2557
2558- Better support of GNU Pth via --with-pth configure option.
2559
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002560- Python/C API now properly exposed to dynamically-loaded extension
2561 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002562
2563- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2564 Don't define MS_SYNC to be zero when it is undefined. Added missing
2565 prototypes in posixmodule.c.
2566
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002567- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002568 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002569
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002570- Fix largefile support on older NetBSD systems and OpenBSD by adding
2571 define for TELL64.
2572
2573
2574Tools and other miscellany
2575
2576- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2577
2578- freeze: The modulefinder now works with 2.0 opcodes.
2579
Tim Petersa3a3a032000-11-30 05:22:44 +00002580- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002581 Move hackery of sys.argv until after the Tk instance has been
2582 created, which allows the application-specific Tkinter
2583 initialization to be executed if present; also pass an explicit
2584 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002585
Jeremy Hylton1b618592000-09-26 05:32:36 +00002586
2587What's new in 2.0 beta 1?
2588=========================
2589
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002590Source Incompatibilities
2591------------------------
2592
2593None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2594such as single-argument append(), connect() and bind(), and changes to
2595str(long) and repr(float).
2596
2597
2598Binary Incompatibilities
2599------------------------
2600
2601- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2602with Python 2.0; these extensions will have to be rebuilt for Python
26032.0.
2604
2605- On Windows, attempting to import a third party extension built for
2606Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2607can do about this. Check your PYTHONPATH environment variable!
2608
2609- Python bytecode files (*.pyc and *.pyo) are not compatible between
2610releases.
2611
2612
2613Overview of Changes Since 1.6
2614-----------------------------
2615
2616There are many new modules (including brand new XML support through
2617the xml package, and i18n support through the gettext module); a list
2618of all new modules is included below. Lots of bugs have been fixed.
2619
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002620The process for making major new changes to the language has changed
2621since Python 1.6. Enhancements must now be documented by a Python
2622Enhancement Proposal (PEP) before they can be accepted.
2623
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002624There are several important syntax enhancements, described in more
2625detail below:
2626
2627 - Augmented assignment, e.g. x += 1
2628
2629 - List comprehensions, e.g. [x**2 for x in range(10)]
2630
2631 - Extended import statement, e.g. import Module as Name
2632
2633 - Extended print statement, e.g. print >> file, "Hello"
2634
2635Other important changes:
2636
2637 - Optional collection of cyclical garbage
2638
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002639Python Enhancement Proposal (PEP)
2640---------------------------------
2641
2642PEP stands for Python Enhancement Proposal. A PEP is a design
2643document providing information to the Python community, or describing
2644a new feature for Python. The PEP should provide a concise technical
2645specification of the feature and a rationale for the feature.
2646
2647We intend PEPs to be the primary mechanisms for proposing new
2648features, for collecting community input on an issue, and for
2649documenting the design decisions that have gone into Python. The PEP
2650author is responsible for building consensus within the community and
2651documenting dissenting opinions.
2652
2653The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002654
2655Augmented Assignment
2656--------------------
2657
2658This must have been the most-requested feature of the past years!
2659Eleven new assignment operators were added:
2660
Guido van Rossume905e952000-09-05 12:42:46 +00002661 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002662
2663For example,
2664
2665 A += B
2666
2667is similar to
2668
2669 A = A + B
2670
2671except that A is evaluated only once (relevant when A is something
2672like dict[index].attr).
2673
2674However, if A is a mutable object, A may be modified in place. Thus,
2675if A is a number or a string, A += B has the same effect as A = A+B
2676(except A is only evaluated once); but if a is a list, A += B has the
2677same effect as A.extend(B)!
2678
2679Classes and built-in object types can override the new operators in
2680order to implement the in-place behavior; the not-in-place behavior is
2681used automatically as a fallback when an object doesn't implement the
2682in-place behavior. For classes, the method name is derived from the
2683method name for the corresponding not-in-place operator by inserting
2684an 'i' in front of the name, e.g. __iadd__ implements in-place
2685__add__.
2686
2687Augmented assignment was implemented by Thomas Wouters.
2688
2689
2690List Comprehensions
2691-------------------
2692
2693This is a flexible new notation for lists whose elements are computed
2694from another list (or lists). The simplest form is:
2695
2696 [<expression> for <variable> in <sequence>]
2697
Guido van Rossum56db0952000-09-06 23:34:25 +00002698For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002699This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002700
2701You can also add a condition:
2702
2703 [<expression> for <variable> in <sequence> if <condition>]
2704
2705For example, [w for w in words if w == w.lower()] would yield the list
2706of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002707than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002708
2709You can also have nested for loops and more than one 'if' clause. For
2710example, here's a function that flattens a sequence of sequences::
2711
2712 def flatten(seq):
2713 return [x for subseq in seq for x in subseq]
2714
2715 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2716
2717This prints
2718
2719 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2720
2721List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002722Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002723
2724
2725Extended Import Statement
2726-------------------------
2727
2728Many people have asked for a way to import a module under a different
2729name. This can be accomplished like this:
2730
2731 import foo
2732 bar = foo
2733 del foo
2734
2735but this common idiom gets old quickly. A simple extension of the
2736import statement now allows this to be written as follows:
2737
2738 import foo as bar
2739
2740There's also a variant for 'from ... import':
2741
2742 from foo import bar as spam
2743
2744This also works with packages; e.g. you can write this:
2745
2746 import test.regrtest as regrtest
2747
2748Note that 'as' is not a new keyword -- it is recognized only in this
2749context (this is only possible because the syntax for the import
2750statement doesn't involve expressions).
2751
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002752Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002753
2754
2755Extended Print Statement
2756------------------------
2757
2758Easily the most controversial new feature, this extension to the print
2759statement adds an option to make the output go to a different file
2760than the default sys.stdout.
2761
2762For example, to write an error message to sys.stderr, you can now
2763write:
2764
2765 print >> sys.stderr, "Error: bad dog!"
2766
2767As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002768evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002769
2770 print >> None, "Hello world"
2771
2772is equivalent to
2773
2774 print "Hello world"
2775
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002776Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002777
2778
2779Optional Collection of Cyclical Garbage
2780---------------------------------------
2781
2782Python is now equipped with a garbage collector that can hunt down
2783cyclical references between Python objects. It's no replacement for
2784reference counting; in fact, it depends on the reference counts being
2785correct, and decides that a set of objects belong to a cycle if all
2786their reference counts can be accounted for from their references to
2787each other. This devious scheme was first proposed by Eric Tiedemann,
2788and brought to implementation by Neil Schemenauer.
2789
2790There's a module "gc" that lets you control some parameters of the
2791garbage collection. There's also an option to the configure script
2792that lets you enable or disable the garbage collection. In 2.0b1,
2793it's on by default, so that we (hopefully) can collect decent user
2794experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002795performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002796off by default in the final 2.0 release.
2797
2798
2799Smaller Changes
2800---------------
2801
2802A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2803map(None, seq1, seq2, ...) when the sequences have the same length;
2804i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2805the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002806zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002807
2808sys.version_info is a tuple (major, minor, micro, level, serial).
2809
2810Dictionaries have an odd new method, setdefault(key, default).
2811dict.setdefault(key, default) returns dict[key] if it exists; if not,
2812it sets dict[key] to default and returns that value. Thus:
2813
2814 dict.setdefault(key, []).append(item)
2815
2816does the same work as this common idiom:
2817
2818 if not dict.has_key(key):
2819 dict[key] = []
2820 dict[key].append(item)
2821
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002822There are two new variants of SyntaxError that are raised for
2823indentation-related errors: IndentationError and TabError.
2824
2825Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2826escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002827
2828The limits on the size of expressions and file in Python source code
2829have been raised from 2**16 to 2**32. Previous versions of Python
2830were limited because the maximum argument size the Python VM accepted
2831was 2**16. This limited the size of object constructor expressions,
2832e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2833limit was raised thanks to a patch by Charles Waldman that effectively
2834fixes the problem. It is now much more likely that you will be
2835limited by available memory than by an arbitrary limit in Python.
2836
2837The interpreter's maximum recursion depth can be modified by Python
2838programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2839limit is the maximum number of recursive calls that can be made by
2840Python code. The limit exists to prevent infinite recursion from
2841overflowing the C stack and causing a core dump. The default value is
28421000. The maximum safe value for a particular platform can be found
2843by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002844
2845New Modules and Packages
2846------------------------
2847
2848atexit - for registering functions to be called when Python exits.
2849
2850imputil - Greg Stein's alternative API for writing custom import
2851hooks.
2852
2853pyexpat - an interface to the Expat XML parser, contributed by Paul
2854Prescod.
2855
2856xml - a new package with XML support code organized (so far) in three
2857subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2858would fill a volume. There's a special feature whereby a
2859user-installed package named _xmlplus overrides the standard
2860xmlpackage; this is intended to give the XML SIG a hook to distribute
2861backwards-compatible updates to the standard xml package.
2862
2863webbrowser - a platform-independent API to launch a web browser.
2864
2865
Guido van Rossume905e952000-09-05 12:42:46 +00002866Changed Modules
2867---------------
2868
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002869array -- new methods for array objects: count, extend, index, pop, and
2870remove
2871
2872binascii -- new functions b2a_hex and a2b_hex that convert between
2873binary data and its hex representation
2874
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002875calendar -- Many new functions that support features including control
2876over which day of the week is the first day, returning strings instead
2877of printing them. Also new symbolic constants for days of week,
2878e.g. MONDAY, ..., SUNDAY.
2879
2880cgi -- FieldStorage objects have a getvalue method that works like a
2881dictionary's get method and returns the value attribute of the object.
2882
2883ConfigParser -- The parser object has new methods has_option,
2884remove_section, remove_option, set, and write. They allow the module
2885to be used for writing config files as well as reading them.
2886
2887ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002888optionally support the RFC 959 REST command.
2889
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002890gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002891
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002892httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2893the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002894
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002895locale -- implement getdefaultlocale for Win32 and Macintosh
2896
2897marshal -- no longer dumps core when marshaling deeply nested or
2898recursive data structures
2899
2900os -- new functions isatty, seteuid, setegid, setreuid, setregid
2901
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002902os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2903support under Unix.
2904
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002905os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002906
2907os.path -- fix semantics of os.path.commonprefix
2908
2909smtplib -- support for sending very long messages
2910
2911socket -- new function getfqdn()
2912
2913readline -- new functions to read, write and truncate history files.
2914The readline section of the library reference manual contains an
2915example.
2916
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002917select -- add interface to poll system call
2918
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002919shutil -- new copyfileobj function
2920
2921SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2922HTTP server.
2923
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002924Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002925
2926urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002927e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002928
2929whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002930
2931
2932Obsolete Modules
2933----------------
2934
2935None. However note that 1.6 made a whole slew of modules obsolete:
2936stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2937poly, zmod, strop, util, whatsound.
2938
2939
2940Changed, New, Obsolete Tools
2941----------------------------
2942
Tim Peters8b092332000-09-05 20:15:25 +00002943None.
Guido van Rossume905e952000-09-05 12:42:46 +00002944
2945
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002946C-level Changes
2947---------------
2948
2949Several cleanup jobs were carried out throughout the source code.
2950
2951All C code was converted to ANSI C; we got rid of all uses of the
2952Py_PROTO() macro, which makes the header files a lot more readable.
2953
2954Most of the portability hacks were moved to a new header file,
2955pyport.h; several other new header files were added and some old
2956header files were removed, in an attempt to create a more rational set
2957of header files. (Few of these ever need to be included explicitly;
2958they are all included by Python.h.)
2959
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002960Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002961and Win64, especially for the new Intel Itanium processor. Mick also
2962added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002963
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002964The C APIs to return an object's size have been update to consistently
2965use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2966previous versions, the abstract interfaces used PyXXX_Length and the
2967concrete interfaces used PyXXX_Size. The old names,
2968e.g. PyObject_Length, are still available for backwards compatibility
2969at the API level, but are deprecated.
2970
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002971The PyOS_CheckStack function has been implemented on Windows by
2972Fredrik Lundh. It prevents Python from failing with a stack overflow
2973on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002974
2975The GC changes resulted in creation of two new slots on object,
2976tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002977the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002978
2979The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002980C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002981
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002982PyErr_Format has been updated to automatically calculate the size of
2983the buffer needed to hold the formatted result string. This change
2984prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002985
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002986New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002987
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002988PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2989that are the same as their non-Ex counterparts except they take an
2990extra flag argument that tells them to close the file when done.
2991
2992XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002993
Tim Peters8b092332000-09-05 20:15:25 +00002994
2995Windows Changes
2996---------------
2997
2998New popen2/popen3/peopen4 in os module (see Changed Modules above).
2999
3000os.popen is much more usable on Windows 95 and 98. See Microsoft
3001Knowledge Base article Q150956. The Win9x workaround described there
3002is implemented by the new w9xpopen.exe helper in the root of your
3003Python installation. Note that Python uses this internally; it is not
3004a standalone program.
3005
3006Administrator privileges are no longer required to install Python
3007on Windows NT or Windows 2000. If you have administrator privileges,
3008Python's registry info will be written under HKEY_LOCAL_MACHINE.
3009Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003010under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003011uses of Python, but will prevent some advanced uses from working
3012(for example, running a Python script as an NT service, or possibly
3013from CGI).
3014
3015[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3016installer; instead, it installs the needed Tcl/Tk files directly in the
3017Python directory. If you already have a Tcl/Tk installation, this
3018wastes some disk space (about 4 Megs) but avoids problems with
3019conflicting Tcl/Tk installations, and makes it much easier for Python
3020to ensure that Tcl/Tk can find all its files.
3021
3022[This was new in 1.6] The Windows installer now installs by default in
3023\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3024
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003025
3026Updates to the changes between 1.5.2 and 1.6
3027--------------------------------------------
3028
3029The 1.6 NEWS file can't be changed after the release is done, so here
3030is some late-breaking news:
3031
3032New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3033and changes to getlocale() and setlocale().
3034
3035The new module is now enabled per default.
3036
3037It is not true that the encodings codecs cannot be used for normal
3038strings: the string.encode() (which is also present on 8-bit strings
3039!) allows using them for 8-bit strings too, e.g. to convert files from
3040cp1252 (Windows) to latin-1 or vice-versa.
3041
3042Japanese codecs are available from Tamito KAJIYAMA:
3043http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3044
3045
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003046======================================================================