blob: d97193d99cd645eb39118805b32a69709716ba04 [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 Rossum4b800852001-12-03 00:54:52 +00007- The "delete attribute" method of descriptor objects is called
8 __delete__, not __del__. In previous releases, it was mistakenly
9 called __del__, which created an unfortunate overloading condition
10 with finalizers. (The "get attribute" and "set attribute" methods
11 are still called __get__ and __set__, respectively.)
12
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000013- Some subtle issues with the super built-in were fixed:
14
15 (a) When super itself is subclassed, its __get__ method would still
16 return an instance of the base class (i.e., of super).
17
18 (b) super(C, C()).__class__ would return C rather than super. This
19 is confusing. To fix this, I decided to change the semantics of
20 super so that it only applies to code attributes, not to data
21 attributes. After all, overriding data attributes is not
22 supported anyway.
23
24 (c) The __get__ method didn't check whether the argument was an
25 instance of the type used in creation of the super instance.
26
27
Tim Petersb3c9af12001-11-17 00:21:57 +000028Core and builtins
29
30Extension modules
31
Martin v. Löwis560da622001-11-24 09:24:51 +000032- gc.get_referents was renamed to gc.get_referrers.
33
Tim Petersb3c9af12001-11-17 00:21:57 +000034Library
35
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +000036- webbrowser defaults to netscape.exe on OS/2 now.
37
Martin v. Löwis652e1912001-11-25 14:50:56 +000038- Tix.ResizeHandle exposes detach_widget, hide, and show.
39
Martin v. Löwis714d2e22001-12-02 12:26:03 +000040- The charset alias windows_1252 has been added.
41
Tim Petersb3c9af12001-11-17 00:21:57 +000042Tools/Demos
43
44Build
45
46C API
47
Tim Peterscffed4b2001-11-29 03:26:37 +000048- PyArg_ParseTupleAndKeywords() requires that the number of entries in
49 the keyword list equals the number of argument specifiers. This
50 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
51 dump core in some bad cases. This has been repaired. As a result,
52 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
53 previously went unchallenged.
54
Tim Petersb3c9af12001-11-17 00:21:57 +000055New platforms
56
57Tests
58
59Windows
60
61Mac
62
63
Tim Peters84362bc2001-10-19 17:55:30 +000064What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000065Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000066===========================
67
68Type/class unification and new-style classes
69
Guido van Rossum3d27df02001-11-15 20:27:54 +000070- Multiple inheritance mixing new-style and classic classes in the
71 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000072
73 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000074 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000075
76 The MRO (method resolution order) for each base class is respected
77 according to its kind, but the MRO for the derived class is computed
78 using new-style MRO rules if any base clase is a new-style class.
79 This needs to be documented.
80
Tim Petersa427a2b2001-10-29 22:25:45 +000081- The new builtin dictionary() constructor, and dictionary type, have
82 been renamed to dict. This reflects a decade of common usage.
83
Guido van Rossum3fc08d22001-11-15 20:33:10 +000084- dict() now accepts an iterable object producing 2-sequences. For
85 example, dict(d.items()) == d for any dictionary d. The argument,
86 and the elements of the argument, can be any iterable objects.
87
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000088- New-style classes can now have a __del__ method, which is called
89 when the instance is deleted (just like for classic classes).
90
Guido van Rossum12d955c2001-10-26 14:56:06 +000091- Assignment to object.__dict__ is now possible, for objects that are
92 instances of new-style classes that have a __dict__ (unless the base
93 class forbids it).
94
Guido van Rossumc8e56452001-10-22 00:43:43 +000095- Methods of built-in types now properly check for keyword arguments
96 (formerly these were silently ignored). The only built-in methods
97 that take keyword arguments are __call__, __init__ and __new__.
98
Guido van Rossum86443212001-10-27 22:28:54 +000099- The socket function has been converted to a type; see below.
100
Tim Peters84362bc2001-10-19 17:55:30 +0000101Core and builtins
102
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000103- Assignment to __debug__ raises SyntaxError at compile-time. This
104 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000105 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000106
Guido van Rossum12d955c2001-10-26 14:56:06 +0000107- Clarified the error messages for unsupported operands to an operator
108 (like 1 + '').
109
Tim Peters84362bc2001-10-19 17:55:30 +0000110Extension modules
111
Tim Peters5ebfd362001-11-13 23:11:19 +0000112- mmap has a new keyword argument, "access", allowing a uniform way for
113 both Windows and Unix users to create read-only, write-through and
114 copy-on-write memory mappings. This was previously possible only on
115 Unix. A new keyword argument was required to support this in a
116 uniform way because the mmap() signuatures had diverged across
117 platforms. Thanks to Jay T Miller for repairing this!
118
Tim Peters169ded02001-11-03 19:57:21 +0000119- By default, the gc.garbage list now contains only those instances in
120 unreachable cycles that have __del__ methods; in 2.1 it contained all
121 instances in unreachable cycles. "Instances" here has been generalized
122 to include instances of both new-style and old-style classes.
123
Guido van Rossum12d955c2001-10-26 14:56:06 +0000124- The socket module defines a new method for socket objects,
125 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000126 send() until all data has been sent. Also, the socket function has
127 been converted to a subclassable type, like list and tuple (etc.)
128 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000129
130- Various bugfixes to the curses module. There is now a test suite
131 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000132
Guido van Rossum692adf12001-10-30 03:03:03 +0000133- binascii.b2a_base64 no longer places an arbitrary restriction of 57
134 bytes on its input.
135
Tim Peters84362bc2001-10-19 17:55:30 +0000136Library
137
Tim Peters5ebfd362001-11-13 23:11:19 +0000138- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000139 convenience function.
140
Tim Peters75335872001-11-03 19:35:43 +0000141- Symbolic group names in regular expressions must be unique. For
142 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
143 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000144 Python 2.2 detects this error at regexp compilation time;
145 previously, the error went undetected, and results were
146 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
147 pattern.subn() methods have been rewritten in C. Also, an
148 experimental function/method finditer() has been added, which works
149 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000150
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000151- Tix exposes more commands through the classes DirSelectBox,
152 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
153 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
154 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
155
Tim Peters98791af2001-10-23 01:59:54 +0000156- Traceback objects are now scanned by cyclic garbage collection, so
157 cycles created by casual use of sys.exc_info() no longer cause
158 permanent memory leaks (provided garbage collection is enabled).
159
Guido van Rossum49192142001-10-24 20:51:44 +0000160- os.extsep -- a new variable needed by the RISCOS support. It is the
161 separator used by extensions, and is '.' on all platforms except
162 RISCOS, where it is '/'. There is no need to use this variable
163 unless you have a masochistic desire to port your code to RISCOS.
164
Barry Warsaw012852b2001-11-16 16:17:27 +0000165- mimetypes.py has optional support for non-standard, but commonly
166 found types. guess_type() and guess_extension() now accept an
167 optional `strict' flag, defaulting to true, which controls whether
168 recognize non-standard types or not. A few non-standard types we
169 know about have been added. Also, when run as a script, there are
170 new -l and -e options.
171
172- statcache is now deprecated.
173
174- email.Utils.formatdate() now produces the preferred RFC 2822 style
175 dates with numeric timezones (it used to produce obsolete dates
176 hard coded to "GMT" timezone). An optional `localtime' flag is
177 added to produce dates in the local timezone, with daylight savings
178 time properly taken into account.
179
180- In pickle and cPickle, instead of masking errors in load() by
181 transforming them into SystemError, we let the original exception
182 propagate out. Also, implement support for __safe_for_unpickling__
183 in pickle, as it already was supported in cPickle.
184
Tim Peters84362bc2001-10-19 17:55:30 +0000185Tools/Demos
186
187Build
188
Barry Warsaw012852b2001-11-16 16:17:27 +0000189- The dbm module is built using libdb1 if available. The bsddb module
190 is built with libdb3 if available.
191
192- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
193
Tim Peters84362bc2001-10-19 17:55:30 +0000194C API
195
Tim Peters1fc240e2001-10-26 05:06:50 +0000196- New function PySequence_Fast_GET_SIZE() returns the size of a non-
197 NULL result from PySequence_Fast(), more quickly than calling
198 PySequence_Size().
199
Barry Warsaw012852b2001-11-16 16:17:27 +0000200- New argument unpacking function PyArg_UnpackTuple() added.
201
202- New functions PyObject_CallFunctionObjArgs() and
203 PyObject_CallMethodObjArgs() have been added to make it more
204 convenient and efficient to call functions and methods from C.
205
206- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
207 possible that this will propagate errors it didn't before.
208
209- New function PyObject_CheckReadBuffer(), which returns true if its
210 argument supports the single-segment readable buffer interface.
211
Tim Peters84362bc2001-10-19 17:55:30 +0000212New platforms
213
Guido van Rossum86443212001-10-27 22:28:54 +0000214- We've finally confirmed that this release builds on HP-UX 11.00,
215 *with* threads, and passes the test suite.
216
Tim Peters7a33d8b2001-11-05 02:51:07 +0000217- Thanks to a series of patches from Michael Muller, Python may build
218 again under OS/2 Visual Age C++.
219
Guido van Rossum49192142001-10-24 20:51:44 +0000220- Updated RISCOS port by Dietmar Schwertberger.
221
Tim Peters84362bc2001-10-19 17:55:30 +0000222Tests
223
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000224- Added a test script for the curses module. It isn't run automatically;
225 regrtest.py must be run with '-u curses' to enable it.
226
Tim Peters84362bc2001-10-19 17:55:30 +0000227Windows
228
Barry Warsaw012852b2001-11-16 16:17:27 +0000229Mac
230
231- PythonScript has been moved to unsupported and is slated to be
232 removed completely in the next release.
233
234- It should now be possible to build applets that work on both OS9 and
235 OSX.
236
237- The core is now linked with CoreServices not Carbon; as a side
238 result, default 8bit encoding on OSX is now ASCII.
239
240- Python should now build on OSX 10.1.1
241
Tim Peters84362bc2001-10-19 17:55:30 +0000242
Tim Petersabf925f2001-09-28 21:53:42 +0000243What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000244Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000245===========================
246
247Type/class unification and new-style classes
248
Guido van Rossum687ae002001-10-15 22:03:32 +0000249- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000250 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000251 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000252 remains: the __dict__ of a new-style class is a read-only proxy; you
253 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000254 __defined__ attribute of new-style types no longer exists, for lack
255 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000256 future a __cache__ may be resurrected with a similar function, if I
257 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000258
Tim Peters1c9ca872001-10-04 06:43:12 +0000259- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
260 always returned None, even when there was a class docstring).
261
262- doctest now finds and runs docstrings attached to new-style classes,
263 class methods, static methods, and properties.
264
Guido van Rossum9074ef62001-10-16 21:34:49 +0000265Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000266
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000267- A very subtle syntactical pitfall in list comprehensions was fixed.
268 For example: [a+b for a in 'abc', for b in 'def']. The comma in
269 this example is a mistake. Previously, this would silently let 'a'
270 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
271 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
272 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
273 Note that [a for a in <singleton>] is a convoluted way to say
274 [<singleton>] anyway, so it's not like any expressiveness is lost.
275
Guido van Rossum9074ef62001-10-16 21:34:49 +0000276- getattr(obj, name, default) now only catches AttributeError, as
277 documented, rather than returning the default value for all
278 exceptions (which could mask bugs in a __getattr__ hook, for
279 example).
280
Fred Drakecb7a6b52001-10-22 18:41:51 +0000281- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000282 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000283 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000284 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000285
Guido van Rossum1c486092001-10-19 02:05:35 +0000286- unicode(obj) now behaves more like str(obj), accepting arbitrary
287 objects, and calling a __unicode__ method if it exists.
288 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000289 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000290
Barry Warsawf6fb1712001-10-19 05:35:40 +0000291- isinstance() now allows any object as the first argument and a
292 class, a type or something with a __bases__ tuple attribute for the
293 second argument. The second argument may also be a tuple of a
294 class, type, or something with __bases__, in which case isinstance()
295 will return true if the first argument is an instance of any of the
296 things contained in the second argument tuple. E.g.
297
298 isinstance(x, (A, B))
299
300 returns true if x is an instance of A or B.
301
Guido van Rossum9074ef62001-10-16 21:34:49 +0000302Extension modules
303
304- thread.start_new_thread() now returns the thread ID (previously None).
305
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000306- binascii has now two quopri support functions, a2b_qp and b2a_qp.
307
Guido van Rossumc524d952001-10-19 01:31:59 +0000308- readline now supports setting the startup_hook and the
309 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000310
Guido van Rossumc524d952001-10-19 01:31:59 +0000311- os and posix supports chroot(), setgroups() and unsetenv() where
312 available. The stat(), fstat(), statvfs() and fstatvfs() functions
313 now return "pseudo-sequences" -- the various fields can now be
314 accessed as attributes (e.g. os.stat("/").st_mtime) but for
315 backwards compatibility they also behave as a fixed-length sequence.
316 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000317 attributes.
318
319- time: localtime(), gmtime() and strptime() now return a
320 pseudo-sequence similar to the os.stat() return value, with
321 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000322
Guido van Rossum9074ef62001-10-16 21:34:49 +0000323- Decompression objects in the zlib module now accept an optional
324 second parameter to decompress() that specifies the maximum amount
325 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000326
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000327- optional SSL support in the socket module now exports OpenSSL
328 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
329 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000330 automatically seed its PRNG. Also, the keyfile and certfile
331 arguments to socket.ssl() are now optional.
332
333- posixmodule (and by extension, the os module on POSIX platforms) now
334 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000335
Guido van Rossum9074ef62001-10-16 21:34:49 +0000336Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000337
Tim Peters7402f792001-10-02 03:53:41 +0000338- doctest now excludes functions and classes not defined by the module
339 being tested, thanks to Tim Hochberg.
340
Fred Drakecb7a6b52001-10-22 18:41:51 +0000341- HotShot, a new profiler implemented using a C-based callback, has
342 been added. This substantially reduces the overhead of profiling,
343 but it is still quite preliminary. Support modules and
344 documentation will be added in upcoming releases (before 2.2 final).
345
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000346- profile now produces correct output in situations where an exception
347 raised in Python is cleared by C code (e.g. hasattr()). This used
348 to cause wrong output, including spurious claims of recursive
349 functions and attribution of time spent to the wrong function.
350
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000351 The code and documentation for the derived OldProfile and HotProfile
352 profiling classes was removed. The code hasn't worked for years (if
353 you tried to use them, they raised exceptions). OldProfile
354 intended to reproduce the behavior of the profiler Python used more
355 than 7 years ago, and isn't interesting anymore. HotProfile intended
356 to provide a faster profiler (but producing less information), and
357 that's a worthy goal we intend to meet via a different approach (but
358 without losing information).
359
Tim Peterscce092d2001-10-09 05:31:56 +0000360- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000361 a much better system-specific calibration constant. The constant can
362 now be specified in an instance constructor, or as a Profile class or
363 instance variable, instead of by editing profile.py's source code.
364 Calibration must still be done manually (see the docs for the profile
365 module).
366
367 Note that Profile.calibrate() must be overriden by subclasses.
368 Improving the accuracy required exploiting detailed knowledge of
369 profiler internals; the earlier method abstracted away the details
370 and measured a simplified model instead, but consequently computed
371 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000372
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000373- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000374 which indicates whether output is intended for the header 'Q'
375 encoding.
376
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000377- The SocketServer.ThreadingMixIn class now closes the request after
378 finish_request() returns. (Not when it errors out though.)
379
Barry Warsawf6fb1712001-10-19 05:35:40 +0000380- The nntplib module's NNTP.body() method has grown a `file' argument
381 to allow saving the message body to a file.
382
383- The email package has added a class email.Parser.HeaderParser which
384 only parses headers and does not recurse into the message's body.
385 Also, the module/class MIMEAudio has been added for representing
386 audio data (contributed by Anthony Baxter).
387
388- ftplib should be able to handle files > 2GB.
389
390- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
391 ON, and OFF.
392
Fred Drakecb7a6b52001-10-22 18:41:51 +0000393- xml.dom.minidom NodeList objects now support the length attribute
394 and item() method as required by the DOM specifications.
395
Guido van Rossumed554f62001-10-02 23:15:37 +0000396Tools/Demos
397
398- Demo/dns was removed. It no longer serves any purpose; a package
399 derived from it is now maintained by Anthony Baxter, see
400 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000401
Barry Warsawf6fb1712001-10-19 05:35:40 +0000402- The freeze tool has been made more robust, and two new options have
403 been added: -X and -E.
404
Tim Petersabf925f2001-09-28 21:53:42 +0000405Build
406
Barry Warsawf6fb1712001-10-19 05:35:40 +0000407- configure will use CXX in LINKCC if CXX is used to build main() and
408 the system requires to link a C++ main using the C++ compiler.
409
Tim Petersabf925f2001-09-28 21:53:42 +0000410C API
411
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000412- The documentation for the tp_compare slot is updated to require that
413 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
414 not correct. This is not yet enforced but will be enforced in
415 Python 2.3; even later, we may use -2 to indicate errors and +2 for
416 "NotImplemented". Right now, -1 should be used for an error return.
417
Tim Petersd38b1c72001-09-30 05:09:37 +0000418- PyLong_AsLongLong() now accepts int (as well as long) arguments.
419 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
420 as long) arguments.
421
Guido van Rossum3c288632001-10-16 21:13:49 +0000422- PyThread_start_new_thread() now returns a long int giving the thread
423 ID, if one can be calculated; it returns -1 for error, 0 if no
424 thread ID is calculated (this is an incompatible change, but only
425 the thread module used this API). This code has only really been
426 tested on Linux and Windows; other platforms please beware (and
427 report any bugs or strange behavior).
428
Guido van Rossum1c486092001-10-19 02:05:35 +0000429- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
430 input.
431
Tim Petersabf925f2001-09-28 21:53:42 +0000432New platforms
433
434Tests
435
436Windows
437
Tim Peters04cf1d32001-10-09 22:39:40 +0000438- Installer: If you install IDLE, and don't disable file-extension
439 registration, a new "Edit with IDLE" context (right-click) menu entry
440 is created for .py and .pyw files.
441
Tim Peters1ce3cf72001-10-01 17:58:40 +0000442- The signal module now supports SIGBREAK on Windows, thanks to Steven
443 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
444 action remains to call Win32 ExitProcess(). This can be changed via
445 signal.signal(). For example:
446
447 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
448 # (SIGINT) behavior.
449 import signal
450 signal.signal(signal.SIGBREAK,
451 signal.default_int_handler)
452
453 try:
454 while 1:
455 pass
456 except KeyboardInterrupt:
457 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
458 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
459 # program without the possibility for any Python-level cleanup).
460 print "Clean exit"
461
Tim Petersabf925f2001-09-28 21:53:42 +0000462
Tim Petersb07352e2001-09-08 01:25:47 +0000463What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000464Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000465===========================
466
Guido van Rossum808eea72001-09-25 04:15:41 +0000467Type/class unification and new-style classes
468
469- pydoc and inspect are now aware of new-style classes;
470 e.g. help(list) at the interactive prompt now shows proper
471 documentation for all operations on list objects.
472
473- Applications using Jim Fulton's ExtensionClass module can now safely
474 be used with Python 2.2. In particular, Zope 2.4.1 now works with
475 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
476 examples also work again. It is hoped that Gtk and Boost also work
477 with 2.2a4 and beyond. (If you can confirm this, please write
478 webmaster@python.org; if there are still problems, please open a bug
479 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000480
Tim Peters66c1a522001-09-24 21:17:50 +0000481- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
482 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
483 in the constructed property object. fget, fset and fdel weren't
484 discoverable from Python in 2.2a3. __doc__ is new, and allows to
485 associate a docstring with a property.
486
Guido van Rossum808eea72001-09-25 04:15:41 +0000487- Comparison overloading is now more completely implemented. For
488 example, a str subclass instance can properly be compared to a str
489 instance, and it can properly overload comparison. Ditto for most
490 other built-in object types.
491
492- The repr() of new-style classes has changed; instead of <type
493 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
494 *except* for built-in types, which are still rendered as <type
495 'Foo'> (to avoid upsetting existing code that might parse or
496 otherwise rely on repr() of certain type objects).
497
498- The repr() of new-style objects is now always <Foo object at XXX>;
499 previously, it was sometimes <Foo instance at XXX>.
500
501- For new-style classes, what was previously called __getattr__ is now
502 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000503 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000504 one in classic classes is defined which is called only if regular
505 attribute access raises AttributeError; to catch *all* attribute
506 access, you can use __getattribute__ (for new-style classes). If
507 both are defined, __getattribute__ is called first, and if it raises
508 AttributeError, __getattr__ is called.
509
510- The __class__ attribute of new-style objects can be assigned to.
511 The new class must have the same C-level object layout as the old
512 class.
513
514- The builtin file type can be subclassed now. In the usual pattern,
515 "file" is the name of the builtin type, and file() is a new builtin
516 constructor, with the same signature as the builtin open() function.
517 file() is now the preferred way to open a file.
518
519- Previously, __new__ would only see sequential arguments passed to
520 the type in a constructor call; __init__ would see both sequential
521 and keyword arguments. This made no sense whatsoever any more, so
522 now both __new__ and __init__ see all arguments.
523
524- Previously, hash() applied to an instance of a subclass of str or
525 unicode always returned 0. This has been repaired.
526
527- Previously, an operation on an instance of a subclass of an
528 immutable type (int, long, float, complex, tuple, str, unicode),
529 where the subtype didn't override the operation (and so the
530 operation was handled by the builtin type), could return that
531 instance instead a value of the base type. For example, if s was of
532 a str sublass type, s[:] returned s as-is. Now it returns a str
533 with the same value as s.
534
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000535- Provisional support for pickling new-style objects has been added.
536
Guido van Rossum808eea72001-09-25 04:15:41 +0000537Core
538
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000539- file.writelines() now accepts any iterable object producing strings.
540
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000541- PyUnicode_FromEncodedObject() now works very much like
542 PyObject_Str(obj) in that it tries to use __str__/tp_str
543 on the object if the object is not a string or buffer. This
544 makes unicode() behave like str() when applied to non-string/buffer
545 objects.
546
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000547- PyFile_WriteObject now passes Unicode objects to the file's write
548 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000549 of a print statement must support Unicode objects, i.e. they must
550 at least convert them into ASCII strings.
551
Guido van Rossum624c8af2001-09-18 15:21:04 +0000552- Thread scheduling on Solaris should be improved; it is no longer
553 necessary to insert a small sleep at the start of a thread in order
554 to let other runnable threads be scheduled.
555
Tim Petersb07352e2001-09-08 01:25:47 +0000556Library
557
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000558- StringIO.StringIO instances and cStringIO.StringIO instances support
559 read character buffer compatible objects for their .write() methods.
560 These objects are converted to strings and then handled as such
561 by the instances.
562
Barry Warsaw2f600732001-09-24 04:28:10 +0000563- The "email" package has been added. This is basically a port of the
564 mimelib package <http://sf.net/projects/mimelib> with API changes
565 and some implementations updated to use iterators and generators.
566
Tim Peters8a9c2842001-09-22 21:30:22 +0000567- difflib.ndiff() and difflib.Differ.compare() are generators now. This
568 restores the ability of Tools/scripts/ndiff.py to start producing output
569 before the entire comparison is complete.
570
Barry Warsaw58b072d2001-09-22 04:44:21 +0000571- StringIO.StringIO instances and cStringIO.StringIO instances support
572 iteration just like file objects (i.e. their .readline() method is
573 called for each iteration until it returns an empty string).
574
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000575- The codecs module has grown four new helper APIs to access
576 builtin codecs: getencoder(), getdecoder(), getreader(),
577 getwriter().
578
Guido van Rossum624c8af2001-09-18 15:21:04 +0000579- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
580 simplifies writing XML RPC servers.
581
Barry Warsaw647d5e82001-09-28 17:01:02 +0000582- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000583 after interpretation of symbolic links. On non-Unix systems, this
584 is an alias for os.path.abspath().
585
Tim Peters16a77ad2001-09-08 04:00:12 +0000586- operator.indexOf() (PySequence_Index() in the C API) now works with any
587 iterable object.
588
Guido van Rossum624c8af2001-09-18 15:21:04 +0000589- smtplib now supports various authentication and security features of
590 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000591
Guido van Rossum624c8af2001-09-18 15:21:04 +0000592- hmac: a new module implementing keyed hashing for message
593 authentication.
594
595- mimetypes now recognizes more extensions and file types. At the
596 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000597
Guido van Rossum624c8af2001-09-18 15:21:04 +0000598- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000599 Python 2.2 bytecode generation. It has also been promoted from a
600 Tool to a standard library package. (Tools/compiler still exists as
601 a sample driver.)
602
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000603Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000604
Tim Petersb07352e2001-09-08 01:25:47 +0000605Build
606
Guido van Rossum624c8af2001-09-18 15:21:04 +0000607- Large file support (LFS) is now automatic when the platform supports
608 it; no more manual configuration tweaks are needed. On Linux, at
609 least, it's possible to have a system whose C library supports large
610 files but whose kernel doesn't; in this case, large file support is
611 still enabled but doesn't do you any good unless you upgrade your
612 kernel or share your Python executable with another system whose
613 kernel has large file support.
614
615- The configure script now supplies plausible defaults in a
616 cross-compilation environment. This doesn't mean that the supplied
617 values are always correct, or that cross-compilation now works
618 flawlessly -- but it's a first step (and it shuts up most of
619 autoconf's warnings about AC_TRY_RUN).
620
621- The Unix build is now a bit less chatty, courtesy of the parser
622 generator. The build is completely silent (except for errors) when
623 using "make -s", thanks to a -q option to setup.py.
624
Tim Petersb07352e2001-09-08 01:25:47 +0000625C API
626
Guido van Rossum624c8af2001-09-18 15:21:04 +0000627- The "structmember" API now supports some new flag bits to deny read
628 and/or write access to attributes in restricted execution mode.
629
Tim Petersb07352e2001-09-08 01:25:47 +0000630New platforms
631
Guido van Rossum624c8af2001-09-18 15:21:04 +0000632- Compaq's iPAQ handheld, running the "familiar" Linux distribution
633 (http://familiar.handhelds.org).
634
Tim Petersb07352e2001-09-08 01:25:47 +0000635Tests
636
Tim Peters8a9c2842001-09-22 21:30:22 +0000637- The "classic" standard tests, which work by comparing stdout to
638 an expected-output file under Lib/test/output/, no longer stop at
639 the first mismatch. Instead the test is run to completion, and a
640 variant of ndiff-style comparison is used to report all differences.
641 This is much easier to understand than the previous style of reporting.
642
643- The unittest-based standard tests now use regrtest's test_main()
644 convention, instead of running as a side-effect of merely being
645 imported. This allows these tests to be run in more natural and
646 flexible ways as unittests, outside the regrtest framework.
647
648- regrtest.py is much better integrated with unittest and doctest now,
649 especially in regard to reporting errors.
650
Tim Petersb07352e2001-09-08 01:25:47 +0000651Windows
652
Guido van Rossum624c8af2001-09-18 15:21:04 +0000653- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000654 that support it (NTFS under Windows 2000). See "What's New in
655 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000656
Tim Petersb07352e2001-09-08 01:25:47 +0000657
Tim Petersedc99312001-08-22 21:36:50 +0000658What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000659Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000660===========================
661
662Core
663
Tim Peters9fffa3e2001-09-04 05:14:19 +0000664- Conversion of long to float now raises OverflowError if the long is too
665 big to represent as a C double.
666
Tim Peters32f453e2001-09-03 08:35:41 +0000667- The 3-argument builtin pow() no longer allows a third non-None argument
668 if either of the first two arguments is a float, or if both are of
669 integer types and the second argument is negative (in which latter case
670 the arguments are converted to float, so this is really the same
671 restriction).
672
Tim Peters5d2b77c2001-09-03 05:47:38 +0000673- The builtin dir() now returns more information, and sometimes much
674 more, generally naming all attributes of an object, and all attributes
675 reachable from the object via its class, and from its class's base
676 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
677 an empty list. In 2.2a3,
678
679 >>> dir([])
680 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
681 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
682 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
683 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
684 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
685 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
686 'reverse', 'sort']
687
688 dir(module) continues to return only the module's attributes, though.
689
Tim Petersbdee63f2001-09-02 03:40:59 +0000690- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000691 than raising OverflowError. This is a partial implementation of PEP
692 237. You can use -Wdefault::OverflowWarning to enable a warning for
693 this situation, and -Werror::OverflowWarning to revert to the old
694 OverflowError exception.
695
Guido van Rossum61c345f2001-09-04 03:26:15 +0000696- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000697 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000698 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
699 -Qold, meaning the / operator has its classic meaning and no
700 warnings are issued. Using -Qwarn issues a run-time warning about
701 all uses of classic division for int and long arguments; -Qwarnall
702 also warns about classic division for float and complex arguments
703 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
704 new division by default, but only in the __main__ module. You can
705 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
706 __main__ module new division, and warns about classic division
707 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000708
Tim Petersbdee63f2001-09-02 03:40:59 +0000709- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000710 long, float, str, unicode, and tuple. (The types complex, list and
711 dictionary can also be subclassed; this was introduced earlier.)
712 Note that restrictions apply when subclassing immutable built-in
713 types: you can only affect the value of the instance by overloading
714 __new__. You can add mutable attributes, and the subclass instances
715 will have a __dict__ attribute, but you cannot change the "value"
716 (as implemented by the base class) of an immutable subclass instance
717 once it is created.
718
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000719- The dictionary constructor now takes an optional argument, a
720 mapping-like object, and initializes the dictionary from its
721 (key, value) pairs.
722
Tim Petersbdee63f2001-09-02 03:40:59 +0000723- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000724 "cooperative super calls" in a multiple inheritance setting. For an
725 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
726
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000727- A new built-in type, property, has been added. This enables the
728 creation of "properties". These are attributes implemented by
729 getter and setter functions (or only one of these for read-only or
730 write-only attributes), without the need to override __getattr__.
731 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000732
Tim Petersbdee63f2001-09-02 03:40:59 +0000733- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000734 liberalized, to allow leading zeroes. Examples of literals now
735 legal that were SyntaxErrors before:
736
737 00.0 0e3 0100j 07.5 00000000000000000008.
738
Tim Petersbdee63f2001-09-02 03:40:59 +0000739- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000740 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
741
Tim Petersedc99312001-08-22 21:36:50 +0000742Library
743
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000744- telnetlib includes symbolic names for the options, and support for
745 setting an option negotiation callback.
746
Tim Petersa40c7932001-09-05 22:36:56 +0000747- The new C standard no longer requires that math libraries set errno to
748 ERANGE on overflow. For platform libraries that exploit this new
749 freedom, Python's overflow-checking was wholly broken. A new overflow-
750 checking scheme attempts to repair that, but may not be reliable on all
751 platforms (C doesn't seem to provide anything both useful and portable
752 in this area anymore).
753
Martin v. Löwis44f86962001-09-05 13:44:54 +0000754- Asynchronous timeout actions are available through the new class
755 threading.Timer.
756
Tim Peters78526162001-09-05 00:53:45 +0000757- math.log and math.log10 now return sensible results for even huge
758 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
759
Tim Petersbdee63f2001-09-02 03:40:59 +0000760- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000761 currently held. See the docs for the imp module.
762
Tim Petersbdee63f2001-09-02 03:40:59 +0000763- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000764 dumps containing ints written on platforms where Python ints are 8 bytes.
765 When read on a box where Python ints are 4 bytes, such values are
766 converted to Python longs.
767
Tim Petersbdee63f2001-09-02 03:40:59 +0000768- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000769 code objects is no longer allowed. This plugs a security hole.
770
Steve Purcell6091cd62001-09-06 16:05:17 +0000771- unittest.TestResult instances no longer store references to tracebacks
772 generated by test failures. This prevents unexpected dangling references
773 to objects that should be garbage collected between tests.
774
Tim Petersedc99312001-08-22 21:36:50 +0000775Tools
776
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000777- Tools/scripts/fixdiv.py has been added which can be used to fix
778 division operators as per PEP 238.
779
Tim Petersedc99312001-08-22 21:36:50 +0000780Build
781
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000782- If you are an adventurous person using Mac OS X you may want to look at
783 Mac/OSX. There is a Makefile there that will build Python as a real Mac
784 application, which can be used for experimenting with Carbon or Cocoa.
785 Discussion of this on pythonmac-sig, please.
786
Tim Peters7eea37e2001-09-04 22:08:56 +0000787C API
788
789- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000790
Tim Peters9fffa3e2001-09-04 05:14:19 +0000791- Note that PyLong_AsDouble can fail! This has always been true, but no
792 callers checked for it. It's more likely to fail now, because overflow
793 errors are properly detected now. The proper way to check:
794
795 double x = PyLong_AsDouble(some_long_object);
796 if (x == -1.0 && PyErr_Occurred()) {
797 /* The conversion failed. */
798 }
799
Tim Petersbdee63f2001-09-02 03:40:59 +0000800- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000801 compile but will not participate in GC. To upgrade an extension
802 module:
803
804 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000805
Neil Schemenauer4042c692001-08-30 15:38:01 +0000806 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
807 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000808
Neil Schemenauer4042c692001-08-30 15:38:01 +0000809 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
810 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000811
Neil Schemenauer4042c692001-08-30 15:38:01 +0000812 - remove PyGC_HEAD_SIZE from object size calculations
813
814 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
815
Tim Petersbdee63f2001-09-02 03:40:59 +0000816- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000817 These can be used safely to construct string objects from a
818 sprintf-style format string (similar to the format string supported
819 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000820
Tim Petersedc99312001-08-22 21:36:50 +0000821New platforms
822
Tim Petersb7da0902001-09-02 23:01:43 +0000823- Stephen Hansen contributed patches sufficient to get a clean compile
824 under Borland C (Windows), but he reports problems running it and ran
825 out of time to complete the port. Volunteers? Expect a MemoryError
826 when importing the types module; this is probably shallow, and
827 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000828
Tim Petersedc99312001-08-22 21:36:50 +0000829Tests
830
831Windows
832
Tim Peters6e13a562001-09-06 00:32:15 +0000833- Large file support is now enabled on Win32 platforms as well as on
834 Win64. This means that, for example, you can use f.tell() and f.seek()
835 to manipulate files larger than 2 gigabytes (provided you have enough
836 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000837 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
838 filesize limit, and large file support makes no difference there.
839 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
840 NTFS has no practical limit on file size, and files of any size can be
841 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000842
Tim Petersbdee63f2001-09-02 03:40:59 +0000843- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000844 points to command.com (patch from Brian Quinlan).
845
Tim Petersedc99312001-08-22 21:36:50 +0000846
Tim Peters20f51a72001-07-21 02:31:40 +0000847What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000848Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000849===========================
850
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000851Build
852
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000853- Tim Peters developed a brand new Windows installer using Wise 8.1,
854 generously donated to us by Wise Solutions.
855
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000856- configure supports a new option --enable-unicode, with the values
857 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
858 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000859
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000860- A new configure option --enable-framework builds a Mac OS X framework,
861 which "make frameworkinstall" will install. This provides a starting
862 point for more mac-like functionality, join pythonmac-sig@python.org
863 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000864
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000865- The NeXT platform is no longer supported.
866
867- The `new' module is now statically linked.
868
Tim Peters0afb6092001-08-15 06:06:44 +0000869Tools
870
871- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000872 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000873 the module docstring for details.
874
Tim Peters20f51a72001-07-21 02:31:40 +0000875Tests
876
Tim Peters5e824c32001-08-12 22:25:01 +0000877- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000878 platforms, allowing to give clearer test result output. regrtest
879 also has optional --use/-u switch to run normally disabled tests
880 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000881
Tim Peters20f51a72001-07-21 02:31:40 +0000882- Several new tests in the standard test suite, with special thanks to
883 Nick Mathewson.
884
885Core
886
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000887- The floor division operator // has been added as outlined in PEP
888 238. The / operator still provides classic division (and will until
889 Python 3.0) unless "from __future__ import division" is included, in
890 which case the / operator will provide true division. The operator
891 module provides truediv() and floordiv() functions. Augmented
892 assignment variants are included, as are the equivalent overloadable
893 methods and C API methods. See the PEP for a full discussion:
894 <http://python.sf.net/peps/pep-0238.html>
895
Tim Peters6cd6a822001-08-17 22:11:27 +0000896- Future statements are now effective in simulated interactive shells
897 (like IDLE). This should "just work" by magic, but read Michael
898 Hudson's "Future statements in simulated shells" PEP 264 for full
899 details: <http://python.sf.net/peps/pep-0264.html>.
900
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000901- The type/class unification (PEP 252-253) was integrated into the
902 trunk and is not so tentative any more (the exact specification of
903 some features is still tentative). A lot of work has done on fixing
904 bugs and adding robustness and features (performance still has to
905 come a long way).
906
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000907- Warnings about a mismatch in the Python API during extension import
908 now use the Python warning framework (which makes it possible to
909 write filters for these warnings).
910
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000911- A function's __dict__ (aka func_dict) will now always be a
912 dictionary. It used to be possible to delete it or set it to None,
913 but now both actions raise TypeErrors. It is still legal to set it
914 to a dictionary object. Getting func.__dict__ before any attributes
915 have been assigned now returns an empty dictionary instead of None.
916
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000917- A new command line option, -E, was added which disables the use of
918 all environment variables, or at least those that are specifically
919 significant to Python. Usually those have a name starting with
920 "PYTHON". This was used to fix a problem where the tests fail if
921 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
922 older distribution.
923
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000924Library
925
Tim Peters5e824c32001-08-12 22:25:01 +0000926- New class Differ and new functions ndiff() and restore() in difflib.py.
927 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000928 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000929
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000930- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
931 value using the minimal quoting required for the value; more
932 reliable than using xml.sax.saxutils.escape() for attribute values.
933
934- Readline completion support for cmd.Cmd was added.
935
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000936- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
937
938- Added function threading.BoundedSemaphore()
939
940- Added Ka-Ping Yee's cgitb.py module.
941
942- The `new' module now exposes the CO_xxx flags.
943
Martin v. Löwis560da622001-11-24 09:24:51 +0000944- The gc module offers the get_referents function.
945
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000946New platforms
947
948C API
949
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000950- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
951 which provide a cross-platform implementations for the
952 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
953 the standard sprintf() and vsprintf() C lib APIs, these versions
954 apply bounds checking on the used buffer which enhances protection
955 against buffer overruns.
956
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000957- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000958 and extensions using different Unicode widths is rendered next to
959 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000960 will result in an ImportError. Unicode extensions writers must make
961 sure to check the Unicode width compatibility in their extensions by
962 using at least one of the mangled Unicode APIs in the extension.
963
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000964- Two new flags METH_NOARGS and METH_O are available in method definition
965 tables to simplify implementation of methods with no arguments and a
966 single untyped argument. Calling such methods is more efficient than
967 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
968 deprecated.
969
Tim Petersc1731372001-08-04 08:12:36 +0000970Windows
971
972- "import module" now compiles module.pyw if it exists and nothing else
973 relevant is found.
974
Tim Peters20f51a72001-07-21 02:31:40 +0000975
Guido van Rossum55a78992001-07-17 17:22:32 +0000976What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000977Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000978===========================
979
980Core
Tim Petersa814db52001-05-14 07:05:58 +0000981
Tim Peters6d6c1a32001-08-02 04:15:00 +0000982- TENTATIVELY, a large amount of code implementing much of what's
983 described in PEP 252 (Making Types Look More Like Classes) and PEP
984 253 (Subtyping Built-in Types) was added. This will be released
985 with Python 2.2a1. Documentation will be provided separately
986 through http://www.python.org/2.2/. The purpose of releasing this
987 with Python 2.2a1 is to test backwards compatibility. It is
988 possible, though not likely, that a decision is made not to release
989 this code as part of 2.2 final, if any serious backwards
990 incompapatibilities are found during alpha testing that cannot be
991 repaired.
992
Guido van Rossum55a78992001-07-17 17:22:32 +0000993- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000994 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000995 more 'yield' statements. See PEP 255. Since this adds a new
996 keyword to the language, this feature must be enabled by including a
997 future statement: "from __future__ import generators" (see PEP 236).
998 Generators will become a standard feature in a future release
999 (probably 2.3). Without this future statement, 'yield' remains an
1000 ordinary identifier, but a warning is issued each time it is used.
1001 (These warnings currently don't conform to the warnings framework of
1002 PEP 230; we intend to fix this in 2.2a2.)
1003
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001004- The UTF-16 codec was modified to be more RFC compliant. It will now
1005 only remove BOM characters at the start of the string and then
1006 only if running in native mode (UTF-16-LE and -BE won't remove a
1007 leading BMO character).
1008
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001009- Strings now have a new method .decode() to complement the already
1010 existing .encode() method. These two methods provide direct access
1011 to the corresponding decoders and encoders of the registered codecs.
1012
1013 To enhance the usability of the .encode() method, the special
1014 casing of Unicode object return values was dropped (Unicode objects
1015 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001016
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001017 Both methods will now return whatever the codec in charge of the
1018 requested encoding returns as object, e.g. Unicode codecs will
1019 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1020 will return u"äöü"). This enables codec writer to create codecs
1021 for various simple to use conversions.
1022
1023 New codecs were added to demonstrate these new features (the .encode()
1024 and .decode() columns indicate the type of the returned objects):
1025
1026 Name | .encode() | .decode() | Description
1027 ----------------------------------------------------------------------
1028 uu | string | string | UU codec (e.g. for email)
1029 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001030 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001031 zlib | string | string | zlib compression
1032 hex | string | string | 2-byte hex codec
1033 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1034
Mark Hammond2a0af792001-05-14 03:09:36 +00001035- Some operating systems now support the concept of a default Unicode
1036 encoding for file system operations. Notably, Windows supports 'mbcs'
1037 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001038 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001039 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001040
1041 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001042 functions that return filenames (such as os.listdir()) to return Python
1043 string objects pre-encoded using the default file system encoding for
1044 the platform. As this encoding is likely to be different from Python's
1045 default encoding, converting this name to a Unicode object before passing
1046 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001047 would attempt to use its default encoding (generally ASCII) rather than
1048 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001049
Tim Petersa814db52001-05-14 07:05:58 +00001050 In general, this change simply removes surprises when working with
1051 Unicode and the file system, making these operations work as you expect,
1052 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001053 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001054
Tim Peters61dff2b2001-05-08 15:43:37 +00001055- Float (and complex) literals in source code were evaluated to full
1056 precision only when running from a .py file; the same code loaded from a
1057 .pyc (or .pyo) file could suffer numeric differences starting at about the
1058 12th significant decimal digit. For example, on a machine with IEEE-754
1059 floating arithmetic,
1060
1061 x = 9007199254740992.0
1062 print long(x)
1063
1064 printed 9007199254740992 if run directly from .py, but 9007199254740000
1065 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1066 str(float) instead of repr(float) when building code objects. marshal
1067 now uses repr(float) instead, which should reproduce floats to full
1068 machine precision (assuming the platform C float<->string I/O conversion
1069 functions are of good quality).
1070
1071 This may cause floating-point results to change in some cases, and
1072 usually for the better, but may also cause numerically unstable
1073 algorithms to break.
1074
Tim Peters2f228e72001-05-13 00:19:31 +00001075- The implementation of dicts suffers fewer collisions, which has speed
1076 benefits. However, the order in which dict entries appear in dict.keys(),
1077 dict.values() and dict.items() may differ from previous releases for a
1078 given dict. Nothing is defined about this order, so no program should
1079 rely on it. Nevertheless, it's easy to write test cases that rely on the
1080 order by accident, typically because of printing the str() or repr() of a
1081 dict to an "expected results" file. See Lib/test/test_support.py's new
1082 sortdict(dict) function for a simple way to display a dict in sorted
1083 order.
1084
Tim Peters7a3bfc32001-06-12 01:22:22 +00001085- Many other small changes to dicts were made, resulting in faster
1086 operation along the most common code paths.
1087
Guido van Rossum10315822001-05-01 20:54:30 +00001088- Dictionary objects now support the "in" operator: "x in dict" means
1089 the same as dict.has_key(x).
1090
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001091- The update() method of dictionaries now accepts generic mapping
1092 objects. Specifically the argument object must support the .keys()
1093 and __getitem__() methods. This allows you to say, for example,
1094 {}.update(UserDict())
1095
Guido van Rossum10315822001-05-01 20:54:30 +00001096- Iterators were added; this is a generalized way of providing values
1097 to a for loop. See PEP 234. There's a new built-in function iter()
1098 to return an iterator. There's a new protocol to get the next value
1099 from an iterator using the next() method (in Python) or the
1100 tp_iternext slot (in C). There's a new protocol to get iterators
1101 using the __iter__() method (in Python) or the tp_iter slot (in C).
1102 Iterating (i.e. a for loop) over a dictionary generates its keys.
1103 Iterating over a file generates its lines.
1104
Tim Petersf553f892001-05-01 20:45:31 +00001105- The following functions were generalized to work nicely with iterator
1106 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001107 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001108 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1109 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001110 join() method of strings
1111 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001112 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1113 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001114 right-hand side of assignment statements with multiple targets, such as
1115 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001116
Tim Petersd85e1022001-05-11 21:51:48 +00001117- Accessing module attributes is significantly faster (for example,
1118 random.random or os.path or yourPythonModule.yourAttribute).
1119
Tim Peterse63415e2001-05-08 04:38:29 +00001120- Comparing dictionary objects via == and != is faster, and now works even
1121 if the keys and values don't support comparisons other than ==.
1122
Tim Peters95bf9392001-05-10 08:32:44 +00001123- Comparing dictionaries in ways other than == and != is slower: there were
1124 insecurities in the dict comparison implementation that could cause Python
1125 to crash if the element comparison routines for the dict keys and/or
1126 values mutated the dicts. Making the code bulletproof slowed it down.
1127
Tim Peterseb28ef22001-06-02 05:27:19 +00001128- Collisions in dicts are resolved via a new approach, which can help
1129 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001130 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001131 faster now. Thanks to Christian Tismer for pointing out the cause and
1132 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001133
Tim Peters52e155e2001-06-16 05:42:57 +00001134- repr() is much faster for large containers (dict, list, tuple).
1135
1136
Tim Petersa814db52001-05-14 07:05:58 +00001137Library
1138
Fred Drake960fdf92001-07-20 18:38:26 +00001139- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1140 were added to the string module. These a locale-indenpendent
1141 constants, unlike letters, lowercase, and uppercase. These are now
1142 use in appropriate locations in the standard library.
1143
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001144- The flags used in dlopen calls can now be configured using
1145 sys.setdlopenflags and queried using sys.getdlopenflags.
1146
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001147- Fredrik Lundh's xmlrpclib is now a standard library module. This
1148 provides full client-side XML-RPC support. In addition,
1149 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1150 one asyncore-based). Thanks to Eric Raymond for the documentation.
1151
Guido van Rossum643d3912001-07-05 14:46:25 +00001152- The xrange() object is simplified: it no longer supports slicing,
1153 repetition, comparisons, efficient 'in' checking, the tolist()
1154 method, or the start, stop and step attributes. See PEP 260.
1155
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001156- A new function fnmatch.filter to filter lists of file names was added.
1157
Barry Warsawffd674d2001-05-22 16:00:10 +00001158- calendar.py uses month and day names based on the current locale.
1159
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001160- strop is now *really* obsolete (this was announced before with 1.6),
1161 and issues DeprecationWarning when used (except for the four items
1162 that are still imported into string.py).
1163
Tim Petersa814db52001-05-14 07:05:58 +00001164- Cookie.py now sorts key+value pairs by key in output strings.
1165
1166- pprint.isrecursive(object) didn't correctly identify recursive objects.
1167 Now it does.
1168
Tim Peters95b3f782001-05-14 18:39:41 +00001169- pprint functions now much faster for large containers (tuple, list, dict).
1170
Tim Peters7b9542a2001-06-10 23:40:19 +00001171- New 'q' and 'Q' format codes in the struct module, corresponding to C
1172 types "long long" and "unsigned long long" (on Windows, __int64). In
1173 native mode, these can be used only when the platform C compiler supports
1174 these types (when HAVE_LONG_LONG is #define'd by the Python config
1175 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001176 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1177 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001178
Guido van Rossum83213cc2001-06-12 16:48:52 +00001179- The site module installs a new built-in function 'help' that invokes
1180 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1181 it displays a message reminding the user to use 'help()' or
1182 'help(object)'.
1183
Tim Petersa814db52001-05-14 07:05:58 +00001184Tests
1185
1186- New test_mutants.py runs dict comparisons where the key and value
1187 comparison operators mutute the dicts randomly during comparison. This
1188 rapidly causes Python to crash under earlier releases (not for the faint
1189 of heart: it can also cause Win9x to freeze or reboot!).
1190
1191- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001192 pprint.isreadable() return sensible results. Also verifies that simple
1193 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001194
Tim Peters4324aa32001-05-28 22:30:08 +00001195C API
1196
1197- Removed the unused last_is_sticky argument from the internal
1198 _PyTuple_Resize(). If this affects you, you were cheating.
1199
1200
Guido van Rossum55a78992001-07-17 17:22:32 +00001201======================================================================
1202
1203
Guido van Rossumffe13be2001-04-16 18:46:45 +00001204What's New in Python 2.1 (final)?
1205=================================
1206
1207We only changed a few things since the last release candidate, all in
1208Python library code:
1209
1210- A bug in the locale module was fixed that affected locales which
1211 define no grouping for numeric formatting.
1212
1213- A few bugs in the weakref module's implementations of weak
1214 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1215 and the test suite was updated to check for these bugs.
1216
1217- An old bug in the os.path.walk() function (introduced in Python
1218 2.0!) was fixed: a non-existent file would cause an exception
1219 instead of being ignored.
1220
1221- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1222 PyChecker.
1223
1224
Guido van Rossum5b08f132001-04-16 02:05:23 +00001225What's New in Python 2.1c2?
1226===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001227
Guido van Rossum5b08f132001-04-16 02:05:23 +00001228A flurry of small changes, and one showstopper fixed in the nick of
1229time made it necessary to release another release candidate. The list
1230here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001231
Guido van Rossum5b08f132001-04-16 02:05:23 +00001232Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001233
Guido van Rossum5b08f132001-04-16 02:05:23 +00001234- Tim discovered a nasty bug in the dictionary code, caused by
1235 PyDict_Next() calling dict_resize(), and the GC code's use of
1236 PyDict_Next() violating an assumption in dict_items(). This was
1237 fixed with considerable amounts of band-aid, but the net effect is a
1238 saner and more robust implementation.
1239
1240- Made a bunch of symbols static that were accidentally global.
1241
1242Build and Ports
1243
1244- The setup.py script didn't check for a new enough version of zlib
1245 (1.1.3 is needed). Now it does.
1246
1247- Changed "make clean" target to also remove shared libraries.
1248
1249- Added a more general warning about the SGI Irix optimizer to README.
1250
1251Library
1252
1253- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1254 omitted the slash between host and file.html.
1255
1256- The mailbox module's _Mailbox class contained a completely broken
1257 and undocumented seek() method. Ripped it out.
1258
1259- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1260 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1261
1262- Fixed a few last-minute bugs in unittest.
1263
1264Extensions
1265
1266- Reverted the patch to the OpenSSL code in socketmodule.c to support
1267 RAND_status() and the EGD, and the subsequent patch that tried to
1268 fix it for pre-0.9.5 versions; the problem with the patch is that on
1269 some systems it issues a warning whenever socket is imported, and
1270 that's unacceptable.
1271
1272Tests
1273
1274- Fixed the pickle tests to work with "import test.test_pickle".
1275
1276- Tweaked test_locale.py to actually run the test Windows.
1277
1278- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1279 not "wb" (which is not a valid mode at all).
1280
1281- Fix pstats browser crashes. Import readline if it exists to make
1282 the user interface nicer.
1283
1284- Add "import thread" to the top of test modules that import the
1285 threading module (test_asynchat and test_threadedtempfile). This
1286 prevents test failures caused by a broken threading module resulting
1287 from a previously caught failed import.
1288
1289- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1290 needed on some platforms (e.g. Solaris 8) when the tests are run
1291 twice in succession.
1292
1293- Skip rather than fail test_sunaudiodev if no audio device is found.
1294
1295
1296What's New in Python 2.1c1?
1297===========================
1298
1299This list was significantly updated when 2.1c2 was released; the 2.1c1
1300release didn't mention most changes that were actually part of 2.1c1:
1301
1302Legal
1303
1304- Copyright was assigned to the Python Software Foundation (PSF) and a
1305 PSF license (very similar to the CNRI license) was added.
1306
1307- The CNRI copyright notice was updated to include 2001.
1308
1309Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001310
Guido van Rossumc9932722001-04-12 02:31:27 +00001311- After a public outcry, assignment to __debug__ is no longer illegal;
1312 instead, a warning is issued. It will become illegal in 2.2.
1313
Guido van Rossum5b08f132001-04-16 02:05:23 +00001314- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1315 "%#x" now always prepends "0x", even if the value is zero.
1316
1317- Fixed some nits in the bytecode compiler.
1318
1319- Fixed core dumps when calling certain kinds of non-functions.
1320
1321- Fixed various core dumps caused by reference count bugs.
1322
1323Build and Ports
1324
1325- Use INSTALL_SCRIPT to install script files.
1326
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001327- New port: SCO Unixware 7, by Billy G. Allie.
1328
Guido van Rossum5b08f132001-04-16 02:05:23 +00001329- Updated RISCOS port.
1330
1331- Updated BeOS port and notes.
1332
1333- Various other porting problems resolved.
1334
1335Library
1336
1337- The TERMIOS and SOCKET modules are now truly obsolete and
1338 unnecessary. Their symbols are incorporated in the termios and
1339 socket modules.
1340
1341- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1342 better tests for pickling.
1343
1344- threading: make Condition.wait() robust against KeyboardInterrupt.
1345
1346- zipfile: add support to zipfile to support opening an archive
1347 represented by an open file rather than a file name. Fix bug where
1348 the archive was not properly closed. Fixed a bug in this bugfix
1349 where flush() was called for a read-only file.
1350
1351- imputil: added an uninstall() method to the ImportManager.
1352
1353- Canvas: fixed bugs in lower() and tkraise() methods.
1354
1355- SocketServer: API change (added overridable close_request() method)
1356 so that the TCP server can explicitly close the request.
1357
1358- pstats: Eric Raymond added a simple interactive statistics browser,
1359 invoked when the module is run as a script.
1360
1361- locale: fixed a problem in format().
1362
1363- webbrowser: made it work when the BROWSER environment variable has a
1364 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1365 KDE 2. Fixed some other nits.
1366
1367- unittest: changes to allow using a different exception than
1368 AssertionError, and added a few more function aliases. Some other
1369 small changes.
1370
1371- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1372
1373- asynchat: fixed a critical bug in asynchat that slipped through the
1374 2.1b2 release. Fixed another rare bug.
1375
1376- Fix some unqualified except: clauses (always a bad code example).
1377
1378XML
1379
1380- pyexpat: new API get_version_string().
1381
1382- Fixed some minidom bugs.
1383
1384Extensions
1385
1386- Fixed a core dump in _weakref. Removed the weakref.mapping()
1387 function (it adds nothing to the API).
1388
1389- Rationalized the use of header files in the readline module, to make
1390 it compile (albeit with some warnings) with the very recent readline
1391 4.2, without breaking for earlier versions.
1392
1393- Hopefully fixed a buffering problem in linuxaudiodev.
1394
1395- Attempted a fix to make the OpenSSL support in the socket module
1396 work again with pre-0.9.5 versions of OpenSSL.
1397
1398Tests
1399
1400- Added a test case for asynchat and asyncore.
1401
1402- Removed coupling between tests where one test failing could break
1403 another.
1404
1405Tools
1406
1407- Ping added an interactive help browser to pydoc, fixed some nits
1408 in the rest of the pydoc code, and added some features to his
1409 inspect module.
1410
1411- An updated python-mode.el version 4.1 which integrates Ken
1412 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1413 much nicer in XEmacs and Emacs. When stepping through your program
1414 with pdb, in either the shell window or the *Python* window, the
1415 source file and line will be tracked by an arrow. Very cool!
1416
1417- IDLE: syntax warnings in interactive mode are changed into errors.
1418
1419- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001420 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001421
1422- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001423
Barry Warsaw11e89c72001-04-11 20:37:57 +00001424
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001425What's New in Python 2.1 beta 2?
1426================================
1427
Guido van Rossum053ae352001-03-22 14:17:21 +00001428(Unlisted are many fixed bugs, more documentation, etc.)
1429
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001430Core language, builtins, and interpreter
1431
Guido van Rossum053ae352001-03-22 14:17:21 +00001432- The nested scopes work (enabled by "from __future__ import
1433 nested_scopes") is completed; in particular, the future now extends
1434 into code executed through exec, eval() and execfile(), and into the
1435 interactive interpreter.
1436
1437- When calling a base class method (e.g. BaseClass.__init__(self)),
1438 this is now allowed even if self is not strictly spoken a class
1439 instance (e.g. when using metaclasses or the Don Beaudry hook).
1440
1441- Slice objects are now comparable but not hashable; this prevents
1442 dict[:] from being accepted but meaningless.
1443
1444- Complex division is now calculated using less braindead algorithms.
1445 This doesn't change semantics except it's more likely to give useful
1446 results in extreme cases. Complex repr() now uses full precision
1447 like float repr().
1448
1449- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1450
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001451- It is illegal to assign to the name __debug__, which is set when the
1452 interpreter starts. It is effectively a compile-time constant.
1453
1454- A warning will be issued if a global statement for a variable
1455 follows a use or assignment of that variable.
1456
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001457Standard library
1458
Guido van Rossum053ae352001-03-22 14:17:21 +00001459- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1460 inspired by JUnit), is now part of the standard library. You now
1461 have a choice of two testing frameworks: unittest requires you to
1462 write testcases as separate code, doctest gathers them from
1463 docstrings. Both approaches have their advantages and
1464 disadvantages.
1465
1466- A new module Tix was added, which wraps the Tix extension library
1467 for Tk. With that module, it is not necessary to statically link
1468 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1469 require" command. See Demo/tix/.
1470
1471- tzparse.py is now obsolete.
1472
1473- In gzip.py, the seek() and tell() methods are removed -- they were
1474 non-functional anyway, and it's better if callers can test for their
1475 existence with hasattr().
1476
1477Python/C API
1478
1479- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1480 that's already in the dictionary during a PyDict_Next() iteration.
1481 This used to fail occasionally when a dictionary resize operation
1482 could be triggered that would rehash all the keys. All other
1483 modifications to the dictionary are still off-limits during a
1484 PyDict_Next() iteration!
1485
1486- New extended APIs related to passing compiler variables around.
1487
1488- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1489 implement isinstance() and issubclass().
1490
1491- Py_BuildValue() now has a "D" conversion to create a Python complex
1492 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001493
Fred Drake4e262a92001-03-22 18:26:47 +00001494- Extensions types which support weak references must now set the
1495 field allocated for the weak reference machinery to NULL themselves;
1496 this is done to avoid the cost of checking each object for having a
1497 weakly referencable type in PyObject_INIT(), since most types are
1498 not weakly referencable.
1499
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001500- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1501 free variables and cell variables to and from the frame's f_locals.
1502
1503- Variants of several functions defined in pythonrun.h have been added
1504 to support the nested_scopes future statement. The variants all end
1505 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1506 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1507 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001508 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001509
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001510Distutils
1511
1512- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1513 into the release tree.
1514
Tim Peters0e57abf2001-05-02 07:39:38 +00001515- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001516 (an uninstaller, more customization of the installer's display)
1517
1518- from Jack Jansen: added Mac-specific code to generate a dialog for
1519 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001520 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001521 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001522
1523- added 'platforms' and 'keywords' to the set of metadata that can be
1524 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001525
1526- applied patches from Jason Tishler to make the compiler class work with
1527 Cygwin.
1528
1529
Tim Peters2fe289a2001-03-01 22:19:38 +00001530What's New in Python 2.1 beta 1?
1531================================
Tim Petersd66595f2001-02-04 03:09:53 +00001532
1533Core language, builtins, and interpreter
1534
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001535- Following an outcry from the community about the amount of code
1536 broken by the nested scopes feature introduced in 2.1a2, we decided
1537 to make this feature optional, and to wait until Python 2.2 (or at
1538 least 6 months) to make it standard. The option can be enabled on a
1539 per-module basis by adding "from __future__ import nested_scopes" at
1540 the beginning of a module (before any other statements, but after
1541 comments and an optional docstring). See PEP 236 (Back to the
1542 __future__) for a description of the __future__ statement. PEP 227
1543 (Statically Nested Scopes) has been updated to reflect this change,
1544 and to clarify the semantics in a number of endcases.
1545
1546- The nested scopes code, when enabled, has been hardened, and most
1547 bugs and memory leaks in it have been fixed.
1548
1549- Compile-time warnings are now generated for a number of conditions
1550 that will break or change in meaning when nested scopes are enabled:
1551
1552 - Using "from...import *" or "exec" without in-clause in a function
1553 scope that also defines a lambda or nested function with one or
1554 more free (non-local) variables. The presence of the import* or
1555 bare exec makes it impossible for the compiler to determine the
1556 exact set of local variables in the outer scope, which makes it
1557 impossible to determine the bindings for free variables in the
1558 inner scope. To avoid the warning about import *, change it into
1559 an import of explicitly name object, or move the import* statement
1560 to the global scope; to avoid the warning about bare exec, use
1561 exec...in... (a good idea anyway -- there's a possibility that
1562 bare exec will be deprecated in the future).
1563
1564 - Use of a global variable in a nested scope with the same name as a
1565 local variable in a surrounding scope. This will change in
1566 meaning with nested scopes: the name in the inner scope will
1567 reference the variable in the outer scope rather than the global
1568 of the same name. To avoid the warning, either rename the outer
1569 variable, or use a global statement in the inner function.
1570
Neil Schemenauera35c6882001-02-27 04:45:05 +00001571- An optional object allocator has been included. This allocator is
1572 optimized for Python objects and should be faster and use less memory
1573 than the standard system allocator. It is not enabled by default
1574 because of possible thread safety problems. The allocator is only
1575 protected by the Python interpreter lock and it is possible that some
1576 extension modules require a thread safe allocator. The object
1577 allocator can be enabled by providing the "--with-pymalloc" option to
1578 configure.
1579
Tim Petersd66595f2001-02-04 03:09:53 +00001580Standard library
1581
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001582- pyexpat now detects the expat version if expat.h defines it. A
1583 number of additional handlers are provided, which are only available
1584 since expat 1.95. In addition, the methods SetParamEntityParsing and
1585 GetInputContext of Parser objects are available with 1.95.x
1586 only. Parser objects now provide the ordered_attributes and
1587 specified_attributes attributes. A new module expat.model was added,
1588 which offers a number of additional constants if 1.95.x is used.
1589
1590- xml.dom offers the new functions registerDOMImplementation and
1591 getDOMImplementation.
1592
1593- xml.dom.minidom offers a toprettyxml method. A number of DOM
1594 conformance issues have been resolved. In particular, Element now
1595 has an hasAttributes method, and the handling of namespaces was
1596 improved.
1597
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001598- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1599 getting information about live Python code, and pydoc.py, a module
1600 for interactively converting docstrings to HTML or text.
1601 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001602 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001603 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1604 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001605
Tim Peters1eff7962001-03-01 02:31:33 +00001606- New library module difflib.py, primarily packaging the SequenceMatcher
1607 class at the heart of the popular ndiff.py file-comparison tool.
1608
1609- doctest.py (a framework for verifying Python code examples in docstrings)
1610 is now part of the std library.
1611
Tim Petersd66595f2001-02-04 03:09:53 +00001612Windows changes
1613
Guido van Rossume3955a82001-03-02 14:05:59 +00001614- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1615 small GUI that lets you browse the module docstrings using your
1616 default web browser.
1617
Tim Peters1eff7962001-03-01 02:31:33 +00001618- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1619 Platforms) is implemented. See
1620
1621 http://python.sourceforge.net/peps/pep-0235.html
1622
1623 for full details, especially the "Current Lower-Left Semantics" section.
1624 The new Windows import rules are simpler than before:
1625
1626 A. If the PYTHONCASEOK environment variable exists, same as
1627 before: silently accept the first case-insensitive match of any
1628 kind; raise ImportError if none found.
1629
1630 B. Else search sys.path for the first case-sensitive match; raise
1631 ImportError if none found.
1632
1633 The same rules have been implented on other platforms with case-
1634 insensitive but case-preserving filesystems too (including Cygwin, and
1635 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001636
Tim Peters25a9ce32001-02-19 07:06:36 +00001637- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1638 what it's supposed to do (and does do under NT and 2000) via direct
1639 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001640 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001641 all Win9x systems before.
1642
Tim Peters1eff7962001-03-01 02:31:33 +00001643- Build: Subproject _test (effectively) renamed to _testcapi.
1644
Tim Peters2fe289a2001-03-01 22:19:38 +00001645New platforms
1646
1647- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1648 Thanks to Steven Majewski!
1649
1650- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1651 Tishler!
1652
Guido van Rossum9089b272001-03-02 06:49:50 +00001653- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1654 Schwertberger! See RISCOS/README for more information -- it seems
1655 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001656 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001657
Tim Peters25a9ce32001-02-19 07:06:36 +00001658
Tim Petersd7b5e882001-01-25 03:36:26 +00001659What's New in Python 2.1 alpha 2?
1660=================================
Tim Peters40ead762001-01-27 05:35:26 +00001661
Tim Petersd7b5e882001-01-25 03:36:26 +00001662Core language, builtins, and interpreter
1663
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001664- Scopes nest. If a name is used in a function or class, but is not
1665 local, the definition in the nearest enclosing function scope will
1666 be used. One consequence of this change is that lambda statements
1667 could reference variables in the namespaces where the lambda is
1668 defined. In some unusual cases, this change will break code.
1669
1670 In all previous version of Python, names were resolved in exactly
1671 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001672 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001673 function A is defined within a function B, the names bound in B are
1674 not visible in A. The new rules make names bound in B visible in A,
1675 unless A contains a name binding that hides the binding in B.
1676
1677 Section 4.1 of the reference manual describes the new scoping rules
1678 in detail. The test script in Lib/test/test_scope.py demonstrates
1679 some of the effects of the change.
1680
1681 The new rules will cause existing code to break if it defines nested
1682 functions where an outer function has local variables with the same
1683 name as globals or builtins used by the inner function. Example:
1684
1685 def munge(str):
1686 def helper(x):
1687 return str(x)
1688 if type(str) != type(''):
1689 str = helper(str)
1690 return str.strip()
1691
1692 Under the old rules, the name str in helper() is bound to the
1693 builtin function str(). Under the new rules, it will be bound to
1694 the argument named str and an error will occur when helper() is
1695 called.
1696
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001697- The compiler will report a SyntaxError if "from ... import *" occurs
1698 in a function or class scope. The language reference has documented
1699 that this case is illegal, but the compiler never checked for it.
1700 The recent introduction of nested scope makes the meaning of this
1701 form of name binding ambiguous. In a future release, the compiler
1702 may allow this form when there is no possibility of ambiguity.
1703
Tim Peters40ead762001-01-27 05:35:26 +00001704- repr(string) is easier to read, now using hex escapes instead of octal,
1705 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1706
1707 >>> "\texample \r\n" + chr(0) + chr(255)
1708 '\texample \r\n\x00\xff' # in 2.1
1709 '\011example \015\012\000\377' # in 2.0
1710
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001711- Functions are now compared and hashed by identity, not by value, since
1712 the func_code attribute is writable.
1713
Fred Drakefb9d7122001-02-01 20:00:40 +00001714- Weak references (PEP 205) have been added. This involves a few
1715 changes in the core, an extension module (_weakref), and a Python
1716 module (weakref). The weakref module is the public interface. It
1717 includes support for "explicit" weak references, proxy objects, and
1718 mappings with weakly held values.
1719
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001720- A 'continue' statement can now appear in a try block within the body
1721 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001722 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001723
Tim Petersd7b5e882001-01-25 03:36:26 +00001724Standard library
1725
Barry Warsaw30dbd142001-01-31 22:14:01 +00001726- mailbox.py now has a new class, PortableUnixMailbox which is
1727 identical to UnixMailbox but uses a more portable scheme for
1728 determining From_ separators. Also, the constructors for all the
1729 classes in this module have a new optional `factory' argument, which
1730 is a callable used when new message classes must be instantiated by
1731 the next() method.
1732
Tim Petersd7b5e882001-01-25 03:36:26 +00001733- random.py is now self-contained, and offers all the functionality of
1734 the now-deprecated whrandom.py. See the docs for details. random.py
1735 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001736 and restoring the internal state of the generator; and jumpahead(n),
1737 for quickly forcing the internal state to be the same as if n calls to
1738 random() had been made. The latter is particularly useful for multi-
1739 threaded programs, creating one instance of the random.Random() class for
1740 each thread, then using .jumpahead() to force each instance to use a
1741 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001742
Tim Peters0de88fc2001-02-01 04:59:18 +00001743- random.py's seed() function is new. For bit-for-bit compatibility with
1744 prior releases, use the whseed function instead. The new seed function
1745 addresses two problems: (1) The old function couldn't produce more than
1746 about 2**24 distinct internal states; the new one about 2**45 (the best
1747 that can be done in the Wichmann-Hill generator). (2) The old function
1748 sometimes produced identical internal states when passed distinct
1749 integers, and there was no simple way to predict when that would happen;
1750 the new one guarantees to produce distinct internal states for all
1751 arguments in [0, 27814431486576L).
1752
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001753- The socket module now supports raw packets on Linux. The socket
1754 family is AF_PACKET.
1755
Tim Peters9ea17ac2001-02-02 05:57:15 +00001756- test_capi.py is a start at running tests of the Python C API. The tests
1757 are implemented by the new Modules/_testmodule.c.
1758
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001759- A new extension module, _symtable, provides provisional access to the
1760 internal symbol table used by the Python compiler. A higher-level
1761 interface will be added on top of _symtable in a future release.
1762
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001763- Removed the obsolete soundex module.
1764
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001765- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1766 the isSameNode method; NamedNodeMap the get method.
1767
1768- xml.sax.expatreader supports the lexical handler property; it
1769 generates comment, startCDATA, and endCDATA events.
1770
Tim Petersee826f82001-01-31 19:39:44 +00001771Windows changes
1772
1773- Build procedure: the zlib project is built in a different way that
1774 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001775 the zlib binary used. See PCbuild\readme.txt for details. Your old
1776 zlib-related directories can be deleted; you'll need to download fresh
1777 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001778
Tim Peters9ea17ac2001-02-02 05:57:15 +00001779- Build: New subproject _test for the benefit of test_capi.py (see above).
1780
Tim Petersb16c56f2001-02-02 21:24:51 +00001781- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1782 interface to some Python compiler internals).
1783
1784- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001785 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001786
Tim Petersa3a3a032000-11-30 05:22:44 +00001787What's New in Python 2.1 alpha 1?
1788=================================
1789
1790Core language, builtins, and interpreter
1791
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001792- There is a new Unicode companion to the PyObject_Str() API
1793 called PyObject_Unicode(). It behaves in the same way as the
1794 former, but assures that the returned value is an Unicode object
1795 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001796
Guido van Rossumf98eda02001-01-17 15:54:45 +00001797- The comparison operators support "rich comparison overloading" (PEP
1798 207). C extension types can provide a rich comparison function in
1799 the new tp_richcompare slot in the type object. The cmp() function
1800 and the C function PyObject_Compare() first try the new rich
1801 comparison operators before trying the old 3-way comparison. There
1802 is also a new C API PyObject_RichCompare() (which also falls back on
1803 the old 3-way comparison, but does not constrain the outcome of the
1804 rich comparison to a Boolean result).
1805
1806 The rich comparison function takes two objects (at least one of
1807 which is guaranteed to have the type that provided the function) and
1808 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1809 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1810 object, which may be NotImplemented (in which case the tp_compare
1811 slot function is used as a fallback, if defined).
1812
1813 Classes can overload individual comparison operators by defining one
1814 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001815 __ge__. There are no explicit "reflected argument" versions of
1816 these; instead, __lt__ and __gt__ are each other's reflection,
1817 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1818 reflection (similar at the C level). No other implications are
1819 made; in particular, Python does not assume that == is the Boolean
1820 inverse of !=, or that < is the Boolean inverse of >=. This makes
1821 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001822
1823 Classes or types that want to implement (in)equality tests but not
1824 the ordering operators (i.e. unordered types) should implement ==
1825 and !=, and raise an error for the ordering operators.
1826
Guido van Rossuma88479f2001-01-18 14:28:08 +00001827 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001828 Boolean; e.g. a matrix type might want to return a matrix of bits
1829 for A < B, giving elementwise comparisons. Such types should ensure
1830 that any interpretation of their value in a Boolean context raises
1831 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1832 at the C level) to always raise an exception.
1833
Guido van Rossuma88479f2001-01-18 14:28:08 +00001834- Complex numbers use rich comparisons to define == and != but raise
1835 an exception for <, <=, > and >=. Unfortunately, this also means
1836 that cmp() of two complex numbers raises an exception when the two
1837 numbers differ. Since it is not mathematically meaningful to compare
1838 complex numbers except for equality, I hope that this doesn't break
1839 too much code.
1840
Tim Peters3389f192001-02-18 08:48:49 +00001841- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001842 not defined by the language, other than that it's arbitrary but
1843 consistent (see the Reference Manual). An implementation detail changed
1844 in 2.1a1 such that None now compares less than any other object. Code
1845 relying on this new behavior (like code that relied on the previous
1846 behavior) does so at its own risk.
1847
Barry Warsaw573b5412001-01-15 20:43:18 +00001848- Functions and methods now support getting and setting arbitrarily
1849 named attributes (PEP 232). Functions have a new __dict__
1850 (a.k.a. func_dict) which hold the function attributes. Methods get
1851 and set attributes on their underlying im_func. It is a TypeError
1852 to set an attribute on a bound method.
1853
Guido van Rossum051e3352001-01-15 19:11:10 +00001854- The xrange() object implementation has been improved so that
1855 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1856 limitation that in this case len(xrange(sys.maxint)) can't be
1857 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1858 work fine as long as the index i doesn't actually reach 2**31.
1859 (Python uses regular ints for sequence and string indices; fixing
1860 that is much more work.)
1861
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001862- Two changes to from...import:
1863
Guido van Rossumba381232001-02-03 15:06:40 +00001864 1) "from M import X" now works even if (after loading module M)
1865 sys.modules['M'] is not a real module; it's basically a getattr()
1866 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001867
1868 2) "from M import *" now looks for M.__all__ to decide which names to
1869 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1870 filters out names starting with '_' as before. Whether or not
1871 __all__ exists, there's no restriction on the type of M.
1872
Guido van Rossumf61f1662001-01-10 20:13:55 +00001873- File objects have a new method, xreadlines(). This is the fastest
1874 way to iterate over all lines in a file:
1875
1876 for line in file.xreadlines():
1877 ...do something to line...
1878
1879 See the xreadlines module (mentioned below) for how to do this for
1880 other file-like objects.
1881
1882- Even if you don't use file.xreadlines(), you may expect a speedup on
1883 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001884 quite a bit in platform-specific ways: on systems (like Linux) that
1885 support flockfile(), getc_unlocked(), and funlockfile(), those are
1886 used by default. On systems (like Windows) without getc_unlocked(),
1887 a complicated (but still thread-safe) method using fgets() is used by
1888 default.
1889
Tim Petersd52269b2001-01-25 06:23:18 +00001890 You can force use of the fgets() method by #define'ing
1891 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001892 getc_unlocked()).
1893
Tim Petersd52269b2001-01-25 06:23:18 +00001894 You can force fgets() not to be used by #define'ing
1895 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001896 test_bufio.py fails -- and let us know if it does!).
1897
1898- In addition, the fileinput module, while still slower than the other
1899 methods on most platforms, has been sped up too, by using
1900 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001901
1902- Support for run-time warnings has been added, including a new
1903 command line option (-W) to specify the disposition of warnings.
1904 See the description of the warnings module below.
1905
1906- Extensive changes have been made to the coercion code. This mostly
1907 affects extension modules (which can now implement mixed-type
1908 numerical operators without having to use coercion), but
1909 occasionally, in boundary cases the coercion semantics have changed
1910 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001911 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001912 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001913 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001914
Guido van Rossumf98eda02001-01-17 15:54:45 +00001915- In connection with the coercion changes, a new built-in singleton
1916 object, NotImplemented is defined. This can be returned for
1917 operations that wish to indicate they are not implemented for a
1918 particular combination of arguments. From C, this is
1919 Py_NotImplemented.
1920
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001921- The interpreter accepts now bytecode files on the command line even
1922 if they do not have a .pyc or .pyo extension. On Linux, after executing
1923
Martin v. Löwise214baa2001-02-04 22:37:56 +00001924import imp,sys,string
1925magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1926reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1927open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001928
1929 any byte code file can be used as an executable (i.e. as an argument
1930 to execve(2)).
1931
Tim Peters9940b802000-12-01 07:59:35 +00001932- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001933 character. In 1.6 and earlier, they never produced a sign,
1934 and raised an error if the value of the long was too large
1935 to fit in a Python int. In 2.0, they produced a sign if and
1936 only if too large to fit in an int. This was inconsistent
1937 across platforms (because the size of an int varies across
1938 platforms), and inconsistent with hex() and oct(). Example:
1939
1940 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001941 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001942 'ffffffbe' # in 2.0 and before, on 32-bit machines
1943 >>> hex(-0x42L)
1944 '-0x42L' # in all versions of Python
1945
Tim Peters9940b802000-12-01 07:59:35 +00001946 The behavior of %d formats for negative Python longs remains
1947 the same as in 2.0 (although in 1.6 and before, they raised
1948 an error if the long didn't fit in a Python int).
1949
1950 %u formats don't make sense for Python longs, but are allowed
1951 and treated the same as %d in 2.1. In 2.0, a negative long
1952 formatted via %u produced a sign if and only if too large to
1953 fit in an int. In 1.6 and earlier, a negative long formatted
1954 via %u raised an error if it was too big to fit in an int.
1955
Guido van Rossum3661d392000-12-12 22:10:31 +00001956- Dictionary objects have an odd new method, popitem(). This removes
1957 an arbitrary item from the dictionary and returns it (in the form of
1958 a (key, value) pair). This can be useful for algorithms that use a
1959 dictionary as a bag of "to do" items and repeatedly need to pick one
1960 item. Such algorithms normally end up running in quadratic time;
1961 using popitem() they can usually be made to run in linear time.
1962
Tim Peters36cdad12000-12-29 02:06:45 +00001963Standard library
1964
Thomas Woutersfe385252001-01-19 23:16:56 +00001965- In the time module, the time argument to the functions strftime,
1966 localtime, gmtime, asctime and ctime is now optional, defaulting to
1967 the current time (in the local timezone).
1968
Guido van Rossumda91f222001-01-15 16:36:08 +00001969- The ftplib module now defaults to passive mode, which is deemed a
1970 more useful default given that clients are often inside firewalls
1971 these days. Note that this could break if ftplib is used to connect
1972 to a *server* that is inside a firewall, from outside; this is
1973 expected to be a very rare situation. To fix that, you can call
1974 ftp.set_pasv(0).
1975
Martin v. Löwis10a27872001-01-13 09:54:41 +00001976- The module site now treats .pth files not only for path configuration,
1977 but also supports extensions to the initialization code: Lines starting
1978 with import are executed.
1979
Guido van Rossumf61f1662001-01-10 20:13:55 +00001980- There's a new module, warnings, which implements a mechanism for
1981 issuing and filtering warnings. There are some new built-in
1982 exceptions that serve as warning categories, and a new command line
1983 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1984 turns warnings into errors). warnings.warn(message[, category])
1985 issues a warning message; this can also be called from C as
1986 PyErr_Warn(category, message).
1987
1988- A new module xreadlines was added. This exports a single factory
1989 function, xreadlines(). The intention is that this code is the
1990 absolutely fastest way to iterate over all lines in an open
1991 file(-like) object:
1992
1993 import xreadlines
1994 for line in xreadlines.xreadlines(file):
1995 ...do something to line...
1996
1997 This is equivalent to the previous the speed record holder using
1998 file.readlines(sizehint). Note that if file is a real file object
1999 (as opposed to a file-like object), this is equivalent:
2000
2001 for line in file.xreadlines():
2002 ...do something to line...
2003
Tim Peters36cdad12000-12-29 02:06:45 +00002004- The bisect module has new functions bisect_left, insort_left,
2005 bisect_right and insort_right. The old names bisect and insort
2006 are now aliases for bisect_right and insort_right. XXX_right
2007 and XXX_left methods differ in what happens when the new element
2008 compares equal to one or more elements already in the list: the
2009 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002010 right. Code that doesn't care where equal elements end up should
2011 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002012
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002013- The new curses.panel module wraps the panel library that forms part
2014 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2015
Guido van Rossumf61f1662001-01-10 20:13:55 +00002016- The SocketServer module now sets the allow_reuse_address flag by
2017 default in the TCPServer class.
2018
2019- A new function, sys._getframe(), returns the stack frame pointer of
2020 the caller. This is intended only as a building block for
2021 higher-level mechanisms such as string interpolation.
2022
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002023- The pyexpat module supports a number of new handlers, which are
2024 available only in expat 1.2. If invocation of a callback fails, it
2025 will report an additional frame in the traceback. Parser objects
2026 participate now in garbage collection. If expat reports an unknown
2027 encoding, pyexpat will try to use a Python codec; that works only
2028 for single-byte charsets. The parser type objects is exposed as
2029 XMLParserObject.
2030
2031- xml.dom now offers standard definitions for symbolic node type and
2032 exception code constants, and a hierarchy of DOM exceptions. minidom
2033 was adjusted to use them.
2034
2035- The conformance of xml.dom.minidom to the DOM specification was
2036 improved. It detects a number of additional error cases; the
2037 previous/next relationship works even when the tree is modified;
2038 Node supports the normalize() method; NamedNodeMap, DocumentType and
2039 DOMImplementation classes were added; Element supports the
2040 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2041 method.
2042
Guido van Rossumf61f1662001-01-10 20:13:55 +00002043Build issues
2044
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002045- For Unix (and Unix-compatible) builds, configuration and building of
2046 extension modules is now greatly automated. Rather than having to
2047 edit the Modules/Setup file to indicate which modules should be
2048 built and where their include files and libraries are, a
2049 distutils-based setup.py script now takes care of building most
2050 extension modules. All extension modules built this way are built
2051 as shared libraries. Only a few modules that must be linked
2052 statically are still listed in the Setup file; you won't need to
2053 edit their configuration.
2054
2055- Python should now build out of the box on Cygwin. If it doesn't,
2056 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002057
2058- Python now always uses its own (renamed) implementation of getopt()
2059 -- there's too much variation among C library getopt()
2060 implementations.
2061
2062- C++ compilers are better supported; the CXX macro is always set to a
2063 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002064
Tim Petersd92dfe02000-12-12 01:18:41 +00002065Windows changes
2066
2067- select module: By default under Windows, a select() call
2068 can specify no more than 64 sockets. Python now boosts
2069 this Microsoft default to 512. If you need even more than
2070 that, see the MS docs (you'll need to #define FD_SETSIZE
2071 and recompile Python from source).
2072
Guido van Rossumf61f1662001-01-10 20:13:55 +00002073- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2074 subdirectory is no more!
2075
Tim Petersa3a3a032000-11-30 05:22:44 +00002076
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002077What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002078=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002079
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002080Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002081changes are in the file HISTORY. If you are making the jump directly
2082from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2083HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002084
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002085Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2086the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2087http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002088
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002089--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002090
2091======================================================================
2092
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002093What's new in 2.0 (since release candidate 1)?
2094==============================================
2095
2096Standard library
2097
2098- The copy_reg module was modified to clarify its intended use: to
2099 register pickle support for extension types, not for classes.
2100 pickle() will raise a TypeError if it is passed a class.
2101
2102- Fixed a bug in gettext's "normalize and expand" code that prevented
2103 it from finding an existing .mo file.
2104
2105- Restored support for HTTP/0.9 servers in httplib.
2106
Tim Peters989b7b92000-10-16 20:24:53 +00002107- The math module was changed to stop raising OverflowError in case of
2108 underflow, and return 0 instead in underflow cases. Whether Python
2109 used to raise OverflowError in case of underflow was platform-
2110 dependent (it did when the platform math library set errno to ERANGE
2111 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002112
2113- Fixed a bug in StringIO that occurred when the file position was not
2114 at the end of the file and write() was called with enough data to
2115 extend past the end of the file.
2116
2117- Fixed a bug that caused Tkinter error messages to get lost on
2118 Windows. The bug was fixed by replacing direct use of
2119 interp->result with Tcl_GetStringResult(interp).
2120
2121- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2122 redirect response.
2123
2124- Several changes were made to distutils: Some debugging code was
2125 removed from util. Fixed the installer used when an external zip
2126 program (like WinZip) is not found; the source code for this
2127 installer is in Misc/distutils. check_lib() was modified to behave
2128 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2129 test for whether installed modules are on sys.path was changed to
2130 use both normcase() and normpath().
2131
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002132- Several minor bugs were fixed in the xml package (the minidom,
2133 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002134
2135- The regression test driver (regrtest.py) behavior when invoked with
2136 -l changed: It now reports a count of objects that are recognized as
2137 garbage but not freed by the garbage collector.
2138
Tim Peters989b7b92000-10-16 20:24:53 +00002139- The regression test for the math module was changed to test
2140 exceptional behavior when the test is run in verbose mode. Python
2141 cannot yet guarantee consistent exception behavior across platforms,
2142 so the exception part of test_math is run only in verbose mode, and
2143 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002144
2145Internals
2146
2147- PyOS_CheckStack() has been disabled on Win64, where it caused
2148 test_sre to fail.
2149
2150Build issues
2151
2152- Changed compiler flags, so that gcc is always invoked with -Wall and
2153 -Wstrict-prototypes. Users compiling Python with GCC should see
2154 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002155 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002156 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002157
Tim Petersa3a3a032000-11-30 05:22:44 +00002158- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002159
2160Tools and other miscellany
2161
2162- The compiler in Tools/compiler was updated to support the new
2163 language features introduced in 2.0: extended print statement, list
2164 comprehensions, and augmented assignments. The new compiler should
2165 also be backwards compatible with Python 1.5.2; the compiler will
2166 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002167 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002168
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002169What's new in 2.0 release candidate 1 (since beta 2)?
2170=====================================================
2171
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002172What is release candidate 1?
2173
2174We believe that release candidate 1 will fix all known bugs that we
2175intend to fix for the 2.0 final release. This release should be a bit
2176more stable than the previous betas. We would like to see even more
2177widespread testing before the final release, so we are producing this
2178release candidate. The final release will be exactly the same unless
2179any show-stopping (or brown bag) bugs are found by testers of the
2180release candidate.
2181
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002182All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002183to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002184
2185Core language, builtins, and interpreter
2186
2187- A bug that caused crashes when __coerce__ was used with augmented
2188 assignment, e.g. +=, was fixed.
2189
2190- Raise ZeroDivisionError when raising zero to a negative number,
2191 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2192 power operator and the result of math.pow(0.0, -2.0) will vary by
2193 platform. On Linux, it raises a ValueError.
2194
2195- A bug in Unicode string interpolation was fixed that occasionally
2196 caused errors with formats including "%%". For example, the
2197 following expression "%% %s" % u"abc" no longer raises a TypeError.
2198
2199- Compilation of deeply nested expressions raises MemoryError instead
2200 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2201
2202- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2203 rendering them useless. They are now written in binary mode again.
2204
2205Standard library
2206
2207- Keyword arguments are now accepted for most pattern and match object
2208 methods in SRE, the standard regular expression engine.
2209
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002210- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002211 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002212
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002213- Several bugs in the Unicode handling and error handling in _tkinter
2214 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002215
2216- Fix memory management errors in Merge() and Tkapp_Call() routines.
2217
2218- Several changes were made to cStringIO to make it compatible with
2219 the file-like object interface and with StringIO. If operations are
2220 performed on a closed object, an exception is raised. The truncate
2221 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002222 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002223
2224- There were many changes made to the linuxaudiodev module and its
2225 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002226 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002227
2228 Note that this module is named poorly, because it should work
2229 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002230 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002231
2232 The module now raises exceptions when errors occur instead of
2233 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2234 audio) and defines a getptr() method that calls the
2235 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2236
2237- The library_version attribute, introduced in an earlier beta, was
2238 removed because it can not be supported with early versions of the C
2239 readline library, which provides no way to determine the version at
2240 compile-time.
2241
2242- The binascii module is now enabled on Win64.
2243
Tim Peters46446d62000-10-09 21:19:31 +00002244- tokenize.py no longer suffers "recursion depth" errors when parsing
2245 programs with very long string literals.
2246
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002247Internals
2248
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002249- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002250 which is called when the interpreter starts up to determine where
2251 the standard library is installed. These vulnerabilities affect all
2252 previous versions of Python and can be exploited by setting very
2253 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2254 setuid Python script, although use of the wrapper in
2255 Misc/setuid-prog.c will eliminate the vulnerability.
2256
2257- Fixed garbage collection bugs in instance creation that were
2258 triggered when errors occurred during initialization. The solution,
2259 applied in cPickle and in PyInstance_New(), is to call
2260 PyObject_GC_Init() after the initialization of the object's
2261 container attributes is complete.
2262
2263- pyexpat adds definitions of PyModule_AddStringConstant and
2264 PyModule_AddObject if the Python version is less than 2.0, which
2265 provides compatibility with PyXML on Python 1.5.2.
2266
2267- If the platform has a bogus definition for LONG_BIT (the number of
2268 bits in a long), an error will be reported at compile time.
2269
2270- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2271 collection crashes and possibly other, unreported crashes.
2272
2273- Fixed a memory leak in _PyUnicode_Fini().
2274
2275Build issues
2276
2277- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002278 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002279 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002280
2281- The mmap.PAGESIZE constant is now initialized using sysconf when
2282 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2283
2284- The md5 file should now compile on all platforms.
2285
2286- The select module now compiles on platforms that do not define
2287 POLLRDNORM and related constants.
2288
2289- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002290 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002291
Jeremy Hylton10921202000-10-09 18:34:12 +00002292- BeOS: A number of changes were made to the build and installation
2293 process. ar-fake now operates on a directory of object files.
2294 dl_export.h is gone, and its macros now appear on the mwcc command
2295 line during build on PPC BeOS.
2296
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002297- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002298 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002299
2300- Cygwin: Support for shared libraries, Tkinter, and sockets.
2301
2302- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2303
2304Tools and other miscellany
2305
2306- Removed debugging prints from main used with freeze.
2307
Tim Peters46446d62000-10-09 21:19:31 +00002308- IDLE auto-indent no longer crashes when it encounters Unicode
2309 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002310
2311What's new in 2.0 beta 2 (since beta 1)?
2312========================================
2313
2314Core language, builtins, and interpreter
2315
Tim Peters482c0212000-09-26 06:33:09 +00002316- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002317 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002318
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002319- Add -h and -V command line options to print the usage message and
2320 Python version number and exit immediately.
2321
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002322- eval() and exec accept Unicode objects as code parameters.
2323
2324- getattr() and setattr() now also accept Unicode objects for the
2325 attribute name, which are converted to strings using the default
2326 encoding before lookup.
2327
2328- Multiplication on string and Unicode now does proper bounds
2329 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2330 string is too long."
2331
2332- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002333 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002334
Jeremy Hylton1b618592000-09-26 05:32:36 +00002335
2336Standard library and extensions
2337
Guido van Rossum5b08f132001-04-16 02:05:23 +00002338- socket module: the OpenSSL code now adds support for RAND_status()
2339 and EGD (Entropy Gathering Device).
2340
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002341- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002342 argument checking; it still takes no arguments.
2343
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002344- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002345
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002346- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002347
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002348- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002349
2350- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002351 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002352
2353- copy: Copy Unicode objects atomically.
2354
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002355- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002356
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002357- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002358
Fred Drake67233bc2000-09-26 16:40:27 +00002359- dbm: Add get() and setdefault() methods to dbm object. Add constant
2360 `library' to module that names the library used. Added doc strings
2361 and method names to error messages. Uses configure to determine
2362 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2363 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002364
2365- distutils: Update to version 0.9.3.
2366
2367- dl: Add several dl.RTLD_ constants.
2368
2369- fpectl: Now supported on FreeBSD.
2370
2371- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2372 found by the collector will be saved in gc.garbage. This is useful
2373 for debugging a program that creates reference cycles.
2374
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002375- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002376 of HTTP class. Do not close socket on zero-length response. Do not
2377 crash when server sends invalid content-length header.
2378
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002379- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002380
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002381- marshal: When reading a short, sign-extend on platforms where shorts
2382 are bigger than 16 bits. When reading a long, repair the unportable
2383 sign extension that was being done for 64-bit machines. (It assumed
2384 that signed right shift sign-extends.)
2385
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002386- operator: Add contains(), invert(), __invert__() as aliases for
2387 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002388
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002389- os: Add support for popen2() and popen3() on all platforms where
2390 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002391
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002392- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002393 clicking on a file in Explorer (or passing the file name to the
2394 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002395
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002396- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002397 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002398
2399- pickle: Now raises ValueError when an invalid pickle that contains
2400 a non-string repr where a string repr was expected. This behavior
2401 matches cPickle.
2402
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002403- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002404
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002405- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002406
2407- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002408 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002409 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002410
2411- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002412 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002413
2414- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002415 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002416 few cycles during startup since the first call to
2417 setdefaultencoding() will initialize the codec registry and the
2418 encodings package.
2419
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002420- socket: Support for size hint in readlines() method of object returned
2421 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002422
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002423- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002424 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002425 is followed by whitespace.
2426
Tim Petersa3a3a032000-11-30 05:22:44 +00002427- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002428
2429- struct: Check ranges for bytes and shorts.
2430
2431- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002432 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002433
2434- Tkinter: Image objects are now guaranteed to have unique ids. Set
2435 event.delta to zero if Tk version doesn't support mousewheel.
2436 Removed some debugging prints.
2437
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002438- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002439
Fred Drake67233bc2000-09-26 16:40:27 +00002440- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002441 which works around a bug in Norton AntiVirus 2000 that leads directly
2442 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002443
2444- xml: New version detection code allows PyXML to override standard
2445 XML package if PyXML version is greater than 0.6.1.
2446
Fred Drake64bb3802000-09-26 16:21:35 +00002447- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2448 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2449 tree only for nodes which are sufficiently interesting to a specific
2450 application. Does not provide the HTML-specific extensions. Still
2451 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002452
Fred Drake64bb3802000-09-26 16:21:35 +00002453- xml.sax: SAX 2 support for Python, including all the handler
2454 interfaces needed to process XML 1.0 compliant XML. Some
2455 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002456
Fred Drake64bb3802000-09-26 16:21:35 +00002457- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2458 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002459
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002460
Jeremy Hylton1b618592000-09-26 05:32:36 +00002461C API
2462
2463- Add three new convenience functions for module initialization --
2464 PyModule_AddObject(), PyModule_AddIntConstant(), and
2465 PyModule_AddStringConstant().
2466
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002467- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002468 removed and add #error to Python.h if NULL isn't defined after
2469 #include of stdio.h.
2470
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002471- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002472 backwards compatibility (at the source level) with old extensions.
2473
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002474- A wrapper API was added for signal() and sigaction(). Instead of
2475 either function, always use PyOS_getsig() to get a signal handler
2476 and PyOS_setsig() to set one. A new convenience typedef
2477 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002478
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002479- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002480 internal data buffer and size of a string object -- or the default
2481 encoded version of a Unicode object.
2482
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002483- PyString_Size() and PyString_AsString() accept Unicode objects.
2484
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002485- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002486 exists). INT_MAX and LONG_MAX will always be defined, even if
2487 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002488
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002489- PyFloat_FromString takes a second argument, pend, that was
2490 effectively useless. It is now officially useless but preserved for
2491 backwards compatibility. If the pend argument is not NULL, *pend is
2492 set to NULL.
2493
2494- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2495 for the attribute name. See note on getattr() above.
2496
2497- A few bug fixes to argument processing for Unicode.
2498 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2499 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2500 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002501 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002502
2503- Py_BuildValue accepts B format (for bgen-generated code).
2504
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002505
Jeremy Hylton1b618592000-09-26 05:32:36 +00002506Internals
2507
2508- On Unix, fix code for finding Python installation directory so that
2509 it works when argv[0] is a relative path.
2510
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002511- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002512 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002513 rather than by generating a copy of the object.
2514
Tim Peters482c0212000-09-26 06:33:09 +00002515- Several of the internal Unicode tables are much smaller now, and
2516 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002517
Jeremy Hylton97693b02000-09-26 17:42:51 +00002518- In the garbage collector: Fixed bug in collection of tuples. Fixed
2519 bug that caused some instances to be removed from the container set
2520 while they were still live. Fixed parsing in gc.set_debug() for
2521 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002522
2523- Fixed refcount problem in instance deallocation that only occurred
2524 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2525
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002526- On Windows, getpythonregpath is now protected against null data in
2527 registry key.
2528
2529- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002530 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002531
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002532
Jeremy Hylton1b618592000-09-26 05:32:36 +00002533Build and platform-specific issues
2534
2535- Better support of GNU Pth via --with-pth configure option.
2536
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002537- Python/C API now properly exposed to dynamically-loaded extension
2538 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002539
2540- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2541 Don't define MS_SYNC to be zero when it is undefined. Added missing
2542 prototypes in posixmodule.c.
2543
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002544- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002545 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002546
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002547- Fix largefile support on older NetBSD systems and OpenBSD by adding
2548 define for TELL64.
2549
2550
2551Tools and other miscellany
2552
2553- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2554
2555- freeze: The modulefinder now works with 2.0 opcodes.
2556
Tim Petersa3a3a032000-11-30 05:22:44 +00002557- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002558 Move hackery of sys.argv until after the Tk instance has been
2559 created, which allows the application-specific Tkinter
2560 initialization to be executed if present; also pass an explicit
2561 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002562
Jeremy Hylton1b618592000-09-26 05:32:36 +00002563
2564What's new in 2.0 beta 1?
2565=========================
2566
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002567Source Incompatibilities
2568------------------------
2569
2570None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2571such as single-argument append(), connect() and bind(), and changes to
2572str(long) and repr(float).
2573
2574
2575Binary Incompatibilities
2576------------------------
2577
2578- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2579with Python 2.0; these extensions will have to be rebuilt for Python
25802.0.
2581
2582- On Windows, attempting to import a third party extension built for
2583Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2584can do about this. Check your PYTHONPATH environment variable!
2585
2586- Python bytecode files (*.pyc and *.pyo) are not compatible between
2587releases.
2588
2589
2590Overview of Changes Since 1.6
2591-----------------------------
2592
2593There are many new modules (including brand new XML support through
2594the xml package, and i18n support through the gettext module); a list
2595of all new modules is included below. Lots of bugs have been fixed.
2596
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002597The process for making major new changes to the language has changed
2598since Python 1.6. Enhancements must now be documented by a Python
2599Enhancement Proposal (PEP) before they can be accepted.
2600
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002601There are several important syntax enhancements, described in more
2602detail below:
2603
2604 - Augmented assignment, e.g. x += 1
2605
2606 - List comprehensions, e.g. [x**2 for x in range(10)]
2607
2608 - Extended import statement, e.g. import Module as Name
2609
2610 - Extended print statement, e.g. print >> file, "Hello"
2611
2612Other important changes:
2613
2614 - Optional collection of cyclical garbage
2615
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002616Python Enhancement Proposal (PEP)
2617---------------------------------
2618
2619PEP stands for Python Enhancement Proposal. A PEP is a design
2620document providing information to the Python community, or describing
2621a new feature for Python. The PEP should provide a concise technical
2622specification of the feature and a rationale for the feature.
2623
2624We intend PEPs to be the primary mechanisms for proposing new
2625features, for collecting community input on an issue, and for
2626documenting the design decisions that have gone into Python. The PEP
2627author is responsible for building consensus within the community and
2628documenting dissenting opinions.
2629
2630The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002631
2632Augmented Assignment
2633--------------------
2634
2635This must have been the most-requested feature of the past years!
2636Eleven new assignment operators were added:
2637
Guido van Rossume905e952000-09-05 12:42:46 +00002638 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002639
2640For example,
2641
2642 A += B
2643
2644is similar to
2645
2646 A = A + B
2647
2648except that A is evaluated only once (relevant when A is something
2649like dict[index].attr).
2650
2651However, if A is a mutable object, A may be modified in place. Thus,
2652if A is a number or a string, A += B has the same effect as A = A+B
2653(except A is only evaluated once); but if a is a list, A += B has the
2654same effect as A.extend(B)!
2655
2656Classes and built-in object types can override the new operators in
2657order to implement the in-place behavior; the not-in-place behavior is
2658used automatically as a fallback when an object doesn't implement the
2659in-place behavior. For classes, the method name is derived from the
2660method name for the corresponding not-in-place operator by inserting
2661an 'i' in front of the name, e.g. __iadd__ implements in-place
2662__add__.
2663
2664Augmented assignment was implemented by Thomas Wouters.
2665
2666
2667List Comprehensions
2668-------------------
2669
2670This is a flexible new notation for lists whose elements are computed
2671from another list (or lists). The simplest form is:
2672
2673 [<expression> for <variable> in <sequence>]
2674
Guido van Rossum56db0952000-09-06 23:34:25 +00002675For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002676This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002677
2678You can also add a condition:
2679
2680 [<expression> for <variable> in <sequence> if <condition>]
2681
2682For example, [w for w in words if w == w.lower()] would yield the list
2683of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002684than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002685
2686You can also have nested for loops and more than one 'if' clause. For
2687example, here's a function that flattens a sequence of sequences::
2688
2689 def flatten(seq):
2690 return [x for subseq in seq for x in subseq]
2691
2692 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2693
2694This prints
2695
2696 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2697
2698List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002699Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002700
2701
2702Extended Import Statement
2703-------------------------
2704
2705Many people have asked for a way to import a module under a different
2706name. This can be accomplished like this:
2707
2708 import foo
2709 bar = foo
2710 del foo
2711
2712but this common idiom gets old quickly. A simple extension of the
2713import statement now allows this to be written as follows:
2714
2715 import foo as bar
2716
2717There's also a variant for 'from ... import':
2718
2719 from foo import bar as spam
2720
2721This also works with packages; e.g. you can write this:
2722
2723 import test.regrtest as regrtest
2724
2725Note that 'as' is not a new keyword -- it is recognized only in this
2726context (this is only possible because the syntax for the import
2727statement doesn't involve expressions).
2728
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002729Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002730
2731
2732Extended Print Statement
2733------------------------
2734
2735Easily the most controversial new feature, this extension to the print
2736statement adds an option to make the output go to a different file
2737than the default sys.stdout.
2738
2739For example, to write an error message to sys.stderr, you can now
2740write:
2741
2742 print >> sys.stderr, "Error: bad dog!"
2743
2744As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002745evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002746
2747 print >> None, "Hello world"
2748
2749is equivalent to
2750
2751 print "Hello world"
2752
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002753Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002754
2755
2756Optional Collection of Cyclical Garbage
2757---------------------------------------
2758
2759Python is now equipped with a garbage collector that can hunt down
2760cyclical references between Python objects. It's no replacement for
2761reference counting; in fact, it depends on the reference counts being
2762correct, and decides that a set of objects belong to a cycle if all
2763their reference counts can be accounted for from their references to
2764each other. This devious scheme was first proposed by Eric Tiedemann,
2765and brought to implementation by Neil Schemenauer.
2766
2767There's a module "gc" that lets you control some parameters of the
2768garbage collection. There's also an option to the configure script
2769that lets you enable or disable the garbage collection. In 2.0b1,
2770it's on by default, so that we (hopefully) can collect decent user
2771experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002772performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002773off by default in the final 2.0 release.
2774
2775
2776Smaller Changes
2777---------------
2778
2779A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2780map(None, seq1, seq2, ...) when the sequences have the same length;
2781i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2782the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002783zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002784
2785sys.version_info is a tuple (major, minor, micro, level, serial).
2786
2787Dictionaries have an odd new method, setdefault(key, default).
2788dict.setdefault(key, default) returns dict[key] if it exists; if not,
2789it sets dict[key] to default and returns that value. Thus:
2790
2791 dict.setdefault(key, []).append(item)
2792
2793does the same work as this common idiom:
2794
2795 if not dict.has_key(key):
2796 dict[key] = []
2797 dict[key].append(item)
2798
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002799There are two new variants of SyntaxError that are raised for
2800indentation-related errors: IndentationError and TabError.
2801
2802Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2803escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002804
2805The limits on the size of expressions and file in Python source code
2806have been raised from 2**16 to 2**32. Previous versions of Python
2807were limited because the maximum argument size the Python VM accepted
2808was 2**16. This limited the size of object constructor expressions,
2809e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2810limit was raised thanks to a patch by Charles Waldman that effectively
2811fixes the problem. It is now much more likely that you will be
2812limited by available memory than by an arbitrary limit in Python.
2813
2814The interpreter's maximum recursion depth can be modified by Python
2815programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2816limit is the maximum number of recursive calls that can be made by
2817Python code. The limit exists to prevent infinite recursion from
2818overflowing the C stack and causing a core dump. The default value is
28191000. The maximum safe value for a particular platform can be found
2820by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002821
2822New Modules and Packages
2823------------------------
2824
2825atexit - for registering functions to be called when Python exits.
2826
2827imputil - Greg Stein's alternative API for writing custom import
2828hooks.
2829
2830pyexpat - an interface to the Expat XML parser, contributed by Paul
2831Prescod.
2832
2833xml - a new package with XML support code organized (so far) in three
2834subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2835would fill a volume. There's a special feature whereby a
2836user-installed package named _xmlplus overrides the standard
2837xmlpackage; this is intended to give the XML SIG a hook to distribute
2838backwards-compatible updates to the standard xml package.
2839
2840webbrowser - a platform-independent API to launch a web browser.
2841
2842
Guido van Rossume905e952000-09-05 12:42:46 +00002843Changed Modules
2844---------------
2845
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002846array -- new methods for array objects: count, extend, index, pop, and
2847remove
2848
2849binascii -- new functions b2a_hex and a2b_hex that convert between
2850binary data and its hex representation
2851
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002852calendar -- Many new functions that support features including control
2853over which day of the week is the first day, returning strings instead
2854of printing them. Also new symbolic constants for days of week,
2855e.g. MONDAY, ..., SUNDAY.
2856
2857cgi -- FieldStorage objects have a getvalue method that works like a
2858dictionary's get method and returns the value attribute of the object.
2859
2860ConfigParser -- The parser object has new methods has_option,
2861remove_section, remove_option, set, and write. They allow the module
2862to be used for writing config files as well as reading them.
2863
2864ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002865optionally support the RFC 959 REST command.
2866
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002867gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002868
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002869httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2870the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002871
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002872locale -- implement getdefaultlocale for Win32 and Macintosh
2873
2874marshal -- no longer dumps core when marshaling deeply nested or
2875recursive data structures
2876
2877os -- new functions isatty, seteuid, setegid, setreuid, setregid
2878
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002879os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2880support under Unix.
2881
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002882os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002883
2884os.path -- fix semantics of os.path.commonprefix
2885
2886smtplib -- support for sending very long messages
2887
2888socket -- new function getfqdn()
2889
2890readline -- new functions to read, write and truncate history files.
2891The readline section of the library reference manual contains an
2892example.
2893
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002894select -- add interface to poll system call
2895
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002896shutil -- new copyfileobj function
2897
2898SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2899HTTP server.
2900
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002901Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002902
2903urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002904e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002905
2906whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002907
2908
2909Obsolete Modules
2910----------------
2911
2912None. However note that 1.6 made a whole slew of modules obsolete:
2913stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2914poly, zmod, strop, util, whatsound.
2915
2916
2917Changed, New, Obsolete Tools
2918----------------------------
2919
Tim Peters8b092332000-09-05 20:15:25 +00002920None.
Guido van Rossume905e952000-09-05 12:42:46 +00002921
2922
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002923C-level Changes
2924---------------
2925
2926Several cleanup jobs were carried out throughout the source code.
2927
2928All C code was converted to ANSI C; we got rid of all uses of the
2929Py_PROTO() macro, which makes the header files a lot more readable.
2930
2931Most of the portability hacks were moved to a new header file,
2932pyport.h; several other new header files were added and some old
2933header files were removed, in an attempt to create a more rational set
2934of header files. (Few of these ever need to be included explicitly;
2935they are all included by Python.h.)
2936
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002937Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002938and Win64, especially for the new Intel Itanium processor. Mick also
2939added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002940
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002941The C APIs to return an object's size have been update to consistently
2942use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2943previous versions, the abstract interfaces used PyXXX_Length and the
2944concrete interfaces used PyXXX_Size. The old names,
2945e.g. PyObject_Length, are still available for backwards compatibility
2946at the API level, but are deprecated.
2947
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002948The PyOS_CheckStack function has been implemented on Windows by
2949Fredrik Lundh. It prevents Python from failing with a stack overflow
2950on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002951
2952The GC changes resulted in creation of two new slots on object,
2953tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002954the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002955
2956The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002957C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002958
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002959PyErr_Format has been updated to automatically calculate the size of
2960the buffer needed to hold the formatted result string. This change
2961prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002962
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002963New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002964
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002965PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2966that are the same as their non-Ex counterparts except they take an
2967extra flag argument that tells them to close the file when done.
2968
2969XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002970
Tim Peters8b092332000-09-05 20:15:25 +00002971
2972Windows Changes
2973---------------
2974
2975New popen2/popen3/peopen4 in os module (see Changed Modules above).
2976
2977os.popen is much more usable on Windows 95 and 98. See Microsoft
2978Knowledge Base article Q150956. The Win9x workaround described there
2979is implemented by the new w9xpopen.exe helper in the root of your
2980Python installation. Note that Python uses this internally; it is not
2981a standalone program.
2982
2983Administrator privileges are no longer required to install Python
2984on Windows NT or Windows 2000. If you have administrator privileges,
2985Python's registry info will be written under HKEY_LOCAL_MACHINE.
2986Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002987under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002988uses of Python, but will prevent some advanced uses from working
2989(for example, running a Python script as an NT service, or possibly
2990from CGI).
2991
2992[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2993installer; instead, it installs the needed Tcl/Tk files directly in the
2994Python directory. If you already have a Tcl/Tk installation, this
2995wastes some disk space (about 4 Megs) but avoids problems with
2996conflicting Tcl/Tk installations, and makes it much easier for Python
2997to ensure that Tcl/Tk can find all its files.
2998
2999[This was new in 1.6] The Windows installer now installs by default in
3000\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3001
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003002
3003Updates to the changes between 1.5.2 and 1.6
3004--------------------------------------------
3005
3006The 1.6 NEWS file can't be changed after the release is done, so here
3007is some late-breaking news:
3008
3009New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3010and changes to getlocale() and setlocale().
3011
3012The new module is now enabled per default.
3013
3014It is not true that the encodings codecs cannot be used for normal
3015strings: the string.encode() (which is also present on 8-bit strings
3016!) allows using them for 8-bit strings too, e.g. to convert files from
3017cp1252 (Windows) to latin-1 or vice-versa.
3018
3019Japanese codecs are available from Tamito KAJIYAMA:
3020http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3021
3022
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003023======================================================================