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Tim Peters909c0912001-12-14 23:16:18 +00001What's New in Python 2.2 final?
2Release date: 21-Dec-2001
3===============================
4
5Type/class unification and new-style classes
6
7Core and builtins
8
9Extension modules
10
11Library
12
13Tools/Demos
14
15Build
16
17C API
18
19New platforms
20
21Tests
22
23Windows
24
25Mac
26
27
Tim Peters6272dfd2001-12-13 19:34:00 +000028What's New in Python 2.2c1?
29Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +000030===========================
31
32Type/class unification and new-style classes
33
Barry Warsaw06557452001-12-14 20:47:12 +000034- Guido's tutorial introduction to the new type/class features has
35 been extensively updated. See
36
37 http://www.python.org/2.2/descrintro.html
38
39 That remains the primary documentation in this area.
40
Guido van Rossum33bab012001-12-05 22:45:48 +000041- Fixed a leak: instance variables declared with __slots__ were never
42 deleted!
43
Guido van Rossum4b800852001-12-03 00:54:52 +000044- The "delete attribute" method of descriptor objects is called
45 __delete__, not __del__. In previous releases, it was mistakenly
46 called __del__, which created an unfortunate overloading condition
47 with finalizers. (The "get attribute" and "set attribute" methods
48 are still called __get__ and __set__, respectively.)
49
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000050- Some subtle issues with the super built-in were fixed:
51
52 (a) When super itself is subclassed, its __get__ method would still
53 return an instance of the base class (i.e., of super).
54
55 (b) super(C, C()).__class__ would return C rather than super. This
56 is confusing. To fix this, I decided to change the semantics of
57 super so that it only applies to code attributes, not to data
58 attributes. After all, overriding data attributes is not
59 supported anyway.
60
61 (c) The __get__ method didn't check whether the argument was an
62 instance of the type used in creation of the super instance.
63
Guido van Rossumcd7b7d62001-12-04 21:02:07 +000064- Previously, hash() of an instance of a subclass of a mutable type
65 (list or dictionary) would return some value, rather than raising
66 TypeError. This has been fixed. Also, directly calling
67 dict.__hash__ and list.__hash__ now raises the same TypeError
68 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +000069
Guido van Rossumd331cb52001-12-05 19:46:42 +000070- New-style objects now support deleting their __dict__. This is for
71 all intents and purposes equivalent to assigning a brand new empty
72 dictionary, but saves space if the object is not used further.
73
Tim Petersb3c9af12001-11-17 00:21:57 +000074Core and builtins
75
Tim Peters3caca232001-12-06 06:23:26 +000076- -Qnew now works as documented in PEP 238: when -Qnew is passed on
77 the command line, all occurrences of "/" use true division instead
78 of classic division. See the PEP for details. Note that "all"
79 means all instances in library and 3rd-party modules, as well as in
80 your own code. As the PEP says, -Qnew is intended for use only in
81 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +000082 Note that test_coercion.py in the standard Python test suite fails
83 under -Qnew; this is expected, and won't be repaired until true
84 division becomes the default (in the meantime, test_coercion is
85 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +000086
Fred Drake6c01e252001-12-14 17:08:12 +000087- complex() now only allows the first argument to be a string
88 argument, and raises TypeError if either the second arg is a string
89 or if the second arg is specified when the first is a string.
90
Tim Petersb3c9af12001-11-17 00:21:57 +000091Extension modules
92
Martin v. Löwis560da622001-11-24 09:24:51 +000093- gc.get_referents was renamed to gc.get_referrers.
94
Tim Petersb3c9af12001-11-17 00:21:57 +000095Library
96
Tim Peters25059d32001-12-07 20:35:43 +000097- Functions in the os.spawn() family now release the global interpreter
98 lock around calling the platform spawn. They should always have done
99 this, but did not before 2.2c1. Multithreaded programs calling
100 an os.spawn function with P_WAIT will no longer block all Python threads
101 until the spawned program completes. It's possible that some programs
102 relies on blocking, although more likely by accident than by design.
103
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000104- webbrowser defaults to netscape.exe on OS/2 now.
105
Martin v. Löwis652e1912001-11-25 14:50:56 +0000106- Tix.ResizeHandle exposes detach_widget, hide, and show.
107
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000108- The charset alias windows_1252 has been added.
109
Barry Warsaw06557452001-12-14 20:47:12 +0000110- types.StringTypes is a tuple containing the defined string types;
111 usually this will be (str, unicode), but if Python was compiled
112 without Unicode support it will be just (str,).
113
114- The pulldom and minidom modules were synchronized to PyXML.
115
Tim Petersb3c9af12001-11-17 00:21:57 +0000116Tools/Demos
117
Barry Warsaw06557452001-12-14 20:47:12 +0000118- A new script called Tools/scripts/google.py was added, which fires
119 off a search on Google.
120
Tim Petersb3c9af12001-11-17 00:21:57 +0000121Build
122
Barry Warsaw06557452001-12-14 20:47:12 +0000123- Note that release builds of Python should arrange to define the
124 preprocessor symbol NDEBUG on the command line (or equivalent).
125 In the 2.2 pre-release series we tried to define this by magic in
126 Python.h instead, but it proved to cause problems for extension
127 authors. The Unix, Windows and Mac builds now all define NDEBUG in
128 release builds via cmdline (or equivalent) instead. Ports to
129 other platforms should do likewise.
130
Jack Jansen1999ef42001-12-06 21:47:20 +0000131- It is no longer necessary to use --with-suffix when building on a
132 case-insensitive file system (such as Mac OS X HFS+). In the build
133 directory an extension is used, but not in the installed python.
134
Tim Petersb3c9af12001-11-17 00:21:57 +0000135C API
136
Tim Petersf582b822001-12-11 18:51:08 +0000137- New function PyDict_MergeFromSeq2() exposes the builtin dict
138 constructor's logic for updating a dictionary from an iterable object
139 producing key-value pairs.
140
Tim Peterscffed4b2001-11-29 03:26:37 +0000141- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000142 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000143 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
144 dump core in some bad cases. This has been repaired. As a result,
145 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
146 previously went unchallenged.
147
Tim Petersb3c9af12001-11-17 00:21:57 +0000148New platforms
149
150Tests
151
152Windows
153
154Mac
155
Jack Jansenffa260f2001-12-06 21:14:00 +0000156- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
157 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000158
Barry Warsaw06557452001-12-14 20:47:12 +0000159- Changed logic for finding python home in Mac OS X framework Pythons.
160 Now sys.executable points to the executable again, in stead of to
161 the shared library. The latter is used only for locating the python
162 home.
163
164
Tim Peters84362bc2001-10-19 17:55:30 +0000165What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000166Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000167===========================
168
169Type/class unification and new-style classes
170
Guido van Rossum3d27df02001-11-15 20:27:54 +0000171- Multiple inheritance mixing new-style and classic classes in the
172 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000173
174 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000175 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000176
177 The MRO (method resolution order) for each base class is respected
178 according to its kind, but the MRO for the derived class is computed
179 using new-style MRO rules if any base clase is a new-style class.
180 This needs to be documented.
181
Tim Petersa427a2b2001-10-29 22:25:45 +0000182- The new builtin dictionary() constructor, and dictionary type, have
183 been renamed to dict. This reflects a decade of common usage.
184
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000185- dict() now accepts an iterable object producing 2-sequences. For
186 example, dict(d.items()) == d for any dictionary d. The argument,
187 and the elements of the argument, can be any iterable objects.
188
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000189- New-style classes can now have a __del__ method, which is called
190 when the instance is deleted (just like for classic classes).
191
Guido van Rossum12d955c2001-10-26 14:56:06 +0000192- Assignment to object.__dict__ is now possible, for objects that are
193 instances of new-style classes that have a __dict__ (unless the base
194 class forbids it).
195
Guido van Rossumc8e56452001-10-22 00:43:43 +0000196- Methods of built-in types now properly check for keyword arguments
197 (formerly these were silently ignored). The only built-in methods
198 that take keyword arguments are __call__, __init__ and __new__.
199
Guido van Rossum86443212001-10-27 22:28:54 +0000200- The socket function has been converted to a type; see below.
201
Tim Peters84362bc2001-10-19 17:55:30 +0000202Core and builtins
203
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000204- Assignment to __debug__ raises SyntaxError at compile-time. This
205 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000206 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000207
Guido van Rossum12d955c2001-10-26 14:56:06 +0000208- Clarified the error messages for unsupported operands to an operator
209 (like 1 + '').
210
Tim Peters84362bc2001-10-19 17:55:30 +0000211Extension modules
212
Tim Peters5ebfd362001-11-13 23:11:19 +0000213- mmap has a new keyword argument, "access", allowing a uniform way for
214 both Windows and Unix users to create read-only, write-through and
215 copy-on-write memory mappings. This was previously possible only on
216 Unix. A new keyword argument was required to support this in a
217 uniform way because the mmap() signuatures had diverged across
218 platforms. Thanks to Jay T Miller for repairing this!
219
Tim Peters169ded02001-11-03 19:57:21 +0000220- By default, the gc.garbage list now contains only those instances in
221 unreachable cycles that have __del__ methods; in 2.1 it contained all
222 instances in unreachable cycles. "Instances" here has been generalized
223 to include instances of both new-style and old-style classes.
224
Guido van Rossum12d955c2001-10-26 14:56:06 +0000225- The socket module defines a new method for socket objects,
226 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000227 send() until all data has been sent. Also, the socket function has
228 been converted to a subclassable type, like list and tuple (etc.)
229 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000230
231- Various bugfixes to the curses module. There is now a test suite
232 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000233
Guido van Rossum692adf12001-10-30 03:03:03 +0000234- binascii.b2a_base64 no longer places an arbitrary restriction of 57
235 bytes on its input.
236
Tim Peters84362bc2001-10-19 17:55:30 +0000237Library
238
Tim Peters5ebfd362001-11-13 23:11:19 +0000239- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000240 convenience function.
241
Tim Peters75335872001-11-03 19:35:43 +0000242- Symbolic group names in regular expressions must be unique. For
243 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
244 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000245 Python 2.2 detects this error at regexp compilation time;
246 previously, the error went undetected, and results were
247 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
248 pattern.subn() methods have been rewritten in C. Also, an
249 experimental function/method finditer() has been added, which works
250 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000251
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000252- Tix exposes more commands through the classes DirSelectBox,
253 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
254 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
255 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
256
Tim Peters98791af2001-10-23 01:59:54 +0000257- Traceback objects are now scanned by cyclic garbage collection, so
258 cycles created by casual use of sys.exc_info() no longer cause
259 permanent memory leaks (provided garbage collection is enabled).
260
Guido van Rossum49192142001-10-24 20:51:44 +0000261- os.extsep -- a new variable needed by the RISCOS support. It is the
262 separator used by extensions, and is '.' on all platforms except
263 RISCOS, where it is '/'. There is no need to use this variable
264 unless you have a masochistic desire to port your code to RISCOS.
265
Barry Warsaw012852b2001-11-16 16:17:27 +0000266- mimetypes.py has optional support for non-standard, but commonly
267 found types. guess_type() and guess_extension() now accept an
268 optional `strict' flag, defaulting to true, which controls whether
269 recognize non-standard types or not. A few non-standard types we
270 know about have been added. Also, when run as a script, there are
271 new -l and -e options.
272
273- statcache is now deprecated.
274
275- email.Utils.formatdate() now produces the preferred RFC 2822 style
276 dates with numeric timezones (it used to produce obsolete dates
277 hard coded to "GMT" timezone). An optional `localtime' flag is
278 added to produce dates in the local timezone, with daylight savings
279 time properly taken into account.
280
281- In pickle and cPickle, instead of masking errors in load() by
282 transforming them into SystemError, we let the original exception
283 propagate out. Also, implement support for __safe_for_unpickling__
284 in pickle, as it already was supported in cPickle.
285
Tim Peters84362bc2001-10-19 17:55:30 +0000286Tools/Demos
287
288Build
289
Barry Warsaw012852b2001-11-16 16:17:27 +0000290- The dbm module is built using libdb1 if available. The bsddb module
291 is built with libdb3 if available.
292
293- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
294
Tim Peters84362bc2001-10-19 17:55:30 +0000295C API
296
Tim Peters1fc240e2001-10-26 05:06:50 +0000297- New function PySequence_Fast_GET_SIZE() returns the size of a non-
298 NULL result from PySequence_Fast(), more quickly than calling
299 PySequence_Size().
300
Barry Warsaw012852b2001-11-16 16:17:27 +0000301- New argument unpacking function PyArg_UnpackTuple() added.
302
303- New functions PyObject_CallFunctionObjArgs() and
304 PyObject_CallMethodObjArgs() have been added to make it more
305 convenient and efficient to call functions and methods from C.
306
307- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
308 possible that this will propagate errors it didn't before.
309
310- New function PyObject_CheckReadBuffer(), which returns true if its
311 argument supports the single-segment readable buffer interface.
312
Tim Peters84362bc2001-10-19 17:55:30 +0000313New platforms
314
Guido van Rossum86443212001-10-27 22:28:54 +0000315- We've finally confirmed that this release builds on HP-UX 11.00,
316 *with* threads, and passes the test suite.
317
Tim Peters7a33d8b2001-11-05 02:51:07 +0000318- Thanks to a series of patches from Michael Muller, Python may build
319 again under OS/2 Visual Age C++.
320
Guido van Rossum49192142001-10-24 20:51:44 +0000321- Updated RISCOS port by Dietmar Schwertberger.
322
Tim Peters84362bc2001-10-19 17:55:30 +0000323Tests
324
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000325- Added a test script for the curses module. It isn't run automatically;
326 regrtest.py must be run with '-u curses' to enable it.
327
Tim Peters84362bc2001-10-19 17:55:30 +0000328Windows
329
Barry Warsaw012852b2001-11-16 16:17:27 +0000330Mac
331
332- PythonScript has been moved to unsupported and is slated to be
333 removed completely in the next release.
334
335- It should now be possible to build applets that work on both OS9 and
336 OSX.
337
338- The core is now linked with CoreServices not Carbon; as a side
339 result, default 8bit encoding on OSX is now ASCII.
340
341- Python should now build on OSX 10.1.1
342
Tim Peters84362bc2001-10-19 17:55:30 +0000343
Tim Petersabf925f2001-09-28 21:53:42 +0000344What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000345Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000346===========================
347
348Type/class unification and new-style classes
349
Guido van Rossum687ae002001-10-15 22:03:32 +0000350- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000351 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000352 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000353 remains: the __dict__ of a new-style class is a read-only proxy; you
354 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000355 __defined__ attribute of new-style types no longer exists, for lack
356 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000357 future a __cache__ may be resurrected with a similar function, if I
358 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000359
Tim Peters1c9ca872001-10-04 06:43:12 +0000360- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
361 always returned None, even when there was a class docstring).
362
363- doctest now finds and runs docstrings attached to new-style classes,
364 class methods, static methods, and properties.
365
Guido van Rossum9074ef62001-10-16 21:34:49 +0000366Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000367
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000368- A very subtle syntactical pitfall in list comprehensions was fixed.
369 For example: [a+b for a in 'abc', for b in 'def']. The comma in
370 this example is a mistake. Previously, this would silently let 'a'
371 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
372 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
373 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
374 Note that [a for a in <singleton>] is a convoluted way to say
375 [<singleton>] anyway, so it's not like any expressiveness is lost.
376
Guido van Rossum9074ef62001-10-16 21:34:49 +0000377- getattr(obj, name, default) now only catches AttributeError, as
378 documented, rather than returning the default value for all
379 exceptions (which could mask bugs in a __getattr__ hook, for
380 example).
381
Fred Drakecb7a6b52001-10-22 18:41:51 +0000382- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000383 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000384 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000385 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000386
Guido van Rossum1c486092001-10-19 02:05:35 +0000387- unicode(obj) now behaves more like str(obj), accepting arbitrary
388 objects, and calling a __unicode__ method if it exists.
389 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000390 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000391
Barry Warsawf6fb1712001-10-19 05:35:40 +0000392- isinstance() now allows any object as the first argument and a
393 class, a type or something with a __bases__ tuple attribute for the
394 second argument. The second argument may also be a tuple of a
395 class, type, or something with __bases__, in which case isinstance()
396 will return true if the first argument is an instance of any of the
397 things contained in the second argument tuple. E.g.
398
399 isinstance(x, (A, B))
400
401 returns true if x is an instance of A or B.
402
Guido van Rossum9074ef62001-10-16 21:34:49 +0000403Extension modules
404
405- thread.start_new_thread() now returns the thread ID (previously None).
406
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000407- binascii has now two quopri support functions, a2b_qp and b2a_qp.
408
Guido van Rossumc524d952001-10-19 01:31:59 +0000409- readline now supports setting the startup_hook and the
410 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000411
Guido van Rossumc524d952001-10-19 01:31:59 +0000412- os and posix supports chroot(), setgroups() and unsetenv() where
413 available. The stat(), fstat(), statvfs() and fstatvfs() functions
414 now return "pseudo-sequences" -- the various fields can now be
415 accessed as attributes (e.g. os.stat("/").st_mtime) but for
416 backwards compatibility they also behave as a fixed-length sequence.
417 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000418 attributes.
419
420- time: localtime(), gmtime() and strptime() now return a
421 pseudo-sequence similar to the os.stat() return value, with
422 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000423
Guido van Rossum9074ef62001-10-16 21:34:49 +0000424- Decompression objects in the zlib module now accept an optional
425 second parameter to decompress() that specifies the maximum amount
426 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000427
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000428- optional SSL support in the socket module now exports OpenSSL
429 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
430 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000431 automatically seed its PRNG. Also, the keyfile and certfile
432 arguments to socket.ssl() are now optional.
433
434- posixmodule (and by extension, the os module on POSIX platforms) now
435 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000436
Guido van Rossum9074ef62001-10-16 21:34:49 +0000437Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000438
Tim Peters7402f792001-10-02 03:53:41 +0000439- doctest now excludes functions and classes not defined by the module
440 being tested, thanks to Tim Hochberg.
441
Fred Drakecb7a6b52001-10-22 18:41:51 +0000442- HotShot, a new profiler implemented using a C-based callback, has
443 been added. This substantially reduces the overhead of profiling,
444 but it is still quite preliminary. Support modules and
445 documentation will be added in upcoming releases (before 2.2 final).
446
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000447- profile now produces correct output in situations where an exception
448 raised in Python is cleared by C code (e.g. hasattr()). This used
449 to cause wrong output, including spurious claims of recursive
450 functions and attribution of time spent to the wrong function.
451
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000452 The code and documentation for the derived OldProfile and HotProfile
453 profiling classes was removed. The code hasn't worked for years (if
454 you tried to use them, they raised exceptions). OldProfile
455 intended to reproduce the behavior of the profiler Python used more
456 than 7 years ago, and isn't interesting anymore. HotProfile intended
457 to provide a faster profiler (but producing less information), and
458 that's a worthy goal we intend to meet via a different approach (but
459 without losing information).
460
Tim Peterscce092d2001-10-09 05:31:56 +0000461- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000462 a much better system-specific calibration constant. The constant can
463 now be specified in an instance constructor, or as a Profile class or
464 instance variable, instead of by editing profile.py's source code.
465 Calibration must still be done manually (see the docs for the profile
466 module).
467
468 Note that Profile.calibrate() must be overriden by subclasses.
469 Improving the accuracy required exploiting detailed knowledge of
470 profiler internals; the earlier method abstracted away the details
471 and measured a simplified model instead, but consequently computed
472 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000473
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000474- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000475 which indicates whether output is intended for the header 'Q'
476 encoding.
477
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000478- The SocketServer.ThreadingMixIn class now closes the request after
479 finish_request() returns. (Not when it errors out though.)
480
Barry Warsawf6fb1712001-10-19 05:35:40 +0000481- The nntplib module's NNTP.body() method has grown a `file' argument
482 to allow saving the message body to a file.
483
484- The email package has added a class email.Parser.HeaderParser which
485 only parses headers and does not recurse into the message's body.
486 Also, the module/class MIMEAudio has been added for representing
487 audio data (contributed by Anthony Baxter).
488
489- ftplib should be able to handle files > 2GB.
490
491- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
492 ON, and OFF.
493
Fred Drakecb7a6b52001-10-22 18:41:51 +0000494- xml.dom.minidom NodeList objects now support the length attribute
495 and item() method as required by the DOM specifications.
496
Guido van Rossumed554f62001-10-02 23:15:37 +0000497Tools/Demos
498
499- Demo/dns was removed. It no longer serves any purpose; a package
500 derived from it is now maintained by Anthony Baxter, see
501 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000502
Barry Warsawf6fb1712001-10-19 05:35:40 +0000503- The freeze tool has been made more robust, and two new options have
504 been added: -X and -E.
505
Tim Petersabf925f2001-09-28 21:53:42 +0000506Build
507
Barry Warsawf6fb1712001-10-19 05:35:40 +0000508- configure will use CXX in LINKCC if CXX is used to build main() and
509 the system requires to link a C++ main using the C++ compiler.
510
Tim Petersabf925f2001-09-28 21:53:42 +0000511C API
512
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000513- The documentation for the tp_compare slot is updated to require that
514 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
515 not correct. This is not yet enforced but will be enforced in
516 Python 2.3; even later, we may use -2 to indicate errors and +2 for
517 "NotImplemented". Right now, -1 should be used for an error return.
518
Tim Petersd38b1c72001-09-30 05:09:37 +0000519- PyLong_AsLongLong() now accepts int (as well as long) arguments.
520 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
521 as long) arguments.
522
Guido van Rossum3c288632001-10-16 21:13:49 +0000523- PyThread_start_new_thread() now returns a long int giving the thread
524 ID, if one can be calculated; it returns -1 for error, 0 if no
525 thread ID is calculated (this is an incompatible change, but only
526 the thread module used this API). This code has only really been
527 tested on Linux and Windows; other platforms please beware (and
528 report any bugs or strange behavior).
529
Guido van Rossum1c486092001-10-19 02:05:35 +0000530- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
531 input.
532
Tim Petersabf925f2001-09-28 21:53:42 +0000533New platforms
534
535Tests
536
537Windows
538
Tim Peters04cf1d32001-10-09 22:39:40 +0000539- Installer: If you install IDLE, and don't disable file-extension
540 registration, a new "Edit with IDLE" context (right-click) menu entry
541 is created for .py and .pyw files.
542
Tim Peters1ce3cf72001-10-01 17:58:40 +0000543- The signal module now supports SIGBREAK on Windows, thanks to Steven
544 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
545 action remains to call Win32 ExitProcess(). This can be changed via
546 signal.signal(). For example:
547
548 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
549 # (SIGINT) behavior.
550 import signal
551 signal.signal(signal.SIGBREAK,
552 signal.default_int_handler)
553
554 try:
555 while 1:
556 pass
557 except KeyboardInterrupt:
558 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
559 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
560 # program without the possibility for any Python-level cleanup).
561 print "Clean exit"
562
Tim Petersabf925f2001-09-28 21:53:42 +0000563
Tim Petersb07352e2001-09-08 01:25:47 +0000564What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000565Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000566===========================
567
Guido van Rossum808eea72001-09-25 04:15:41 +0000568Type/class unification and new-style classes
569
570- pydoc and inspect are now aware of new-style classes;
571 e.g. help(list) at the interactive prompt now shows proper
572 documentation for all operations on list objects.
573
574- Applications using Jim Fulton's ExtensionClass module can now safely
575 be used with Python 2.2. In particular, Zope 2.4.1 now works with
576 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
577 examples also work again. It is hoped that Gtk and Boost also work
578 with 2.2a4 and beyond. (If you can confirm this, please write
579 webmaster@python.org; if there are still problems, please open a bug
580 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000581
Tim Peters66c1a522001-09-24 21:17:50 +0000582- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
583 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
584 in the constructed property object. fget, fset and fdel weren't
585 discoverable from Python in 2.2a3. __doc__ is new, and allows to
586 associate a docstring with a property.
587
Guido van Rossum808eea72001-09-25 04:15:41 +0000588- Comparison overloading is now more completely implemented. For
589 example, a str subclass instance can properly be compared to a str
590 instance, and it can properly overload comparison. Ditto for most
591 other built-in object types.
592
593- The repr() of new-style classes has changed; instead of <type
594 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
595 *except* for built-in types, which are still rendered as <type
596 'Foo'> (to avoid upsetting existing code that might parse or
597 otherwise rely on repr() of certain type objects).
598
599- The repr() of new-style objects is now always <Foo object at XXX>;
600 previously, it was sometimes <Foo instance at XXX>.
601
602- For new-style classes, what was previously called __getattr__ is now
603 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000604 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000605 one in classic classes is defined which is called only if regular
606 attribute access raises AttributeError; to catch *all* attribute
607 access, you can use __getattribute__ (for new-style classes). If
608 both are defined, __getattribute__ is called first, and if it raises
609 AttributeError, __getattr__ is called.
610
611- The __class__ attribute of new-style objects can be assigned to.
612 The new class must have the same C-level object layout as the old
613 class.
614
615- The builtin file type can be subclassed now. In the usual pattern,
616 "file" is the name of the builtin type, and file() is a new builtin
617 constructor, with the same signature as the builtin open() function.
618 file() is now the preferred way to open a file.
619
620- Previously, __new__ would only see sequential arguments passed to
621 the type in a constructor call; __init__ would see both sequential
622 and keyword arguments. This made no sense whatsoever any more, so
623 now both __new__ and __init__ see all arguments.
624
625- Previously, hash() applied to an instance of a subclass of str or
626 unicode always returned 0. This has been repaired.
627
628- Previously, an operation on an instance of a subclass of an
629 immutable type (int, long, float, complex, tuple, str, unicode),
630 where the subtype didn't override the operation (and so the
631 operation was handled by the builtin type), could return that
632 instance instead a value of the base type. For example, if s was of
633 a str sublass type, s[:] returned s as-is. Now it returns a str
634 with the same value as s.
635
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000636- Provisional support for pickling new-style objects has been added.
637
Guido van Rossum808eea72001-09-25 04:15:41 +0000638Core
639
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000640- file.writelines() now accepts any iterable object producing strings.
641
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000642- PyUnicode_FromEncodedObject() now works very much like
643 PyObject_Str(obj) in that it tries to use __str__/tp_str
644 on the object if the object is not a string or buffer. This
645 makes unicode() behave like str() when applied to non-string/buffer
646 objects.
647
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000648- PyFile_WriteObject now passes Unicode objects to the file's write
649 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000650 of a print statement must support Unicode objects, i.e. they must
651 at least convert them into ASCII strings.
652
Guido van Rossum624c8af2001-09-18 15:21:04 +0000653- Thread scheduling on Solaris should be improved; it is no longer
654 necessary to insert a small sleep at the start of a thread in order
655 to let other runnable threads be scheduled.
656
Tim Petersb07352e2001-09-08 01:25:47 +0000657Library
658
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000659- StringIO.StringIO instances and cStringIO.StringIO instances support
660 read character buffer compatible objects for their .write() methods.
661 These objects are converted to strings and then handled as such
662 by the instances.
663
Barry Warsaw2f600732001-09-24 04:28:10 +0000664- The "email" package has been added. This is basically a port of the
665 mimelib package <http://sf.net/projects/mimelib> with API changes
666 and some implementations updated to use iterators and generators.
667
Tim Peters8a9c2842001-09-22 21:30:22 +0000668- difflib.ndiff() and difflib.Differ.compare() are generators now. This
669 restores the ability of Tools/scripts/ndiff.py to start producing output
670 before the entire comparison is complete.
671
Barry Warsaw58b072d2001-09-22 04:44:21 +0000672- StringIO.StringIO instances and cStringIO.StringIO instances support
673 iteration just like file objects (i.e. their .readline() method is
674 called for each iteration until it returns an empty string).
675
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000676- The codecs module has grown four new helper APIs to access
677 builtin codecs: getencoder(), getdecoder(), getreader(),
678 getwriter().
679
Guido van Rossum624c8af2001-09-18 15:21:04 +0000680- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
681 simplifies writing XML RPC servers.
682
Barry Warsaw647d5e82001-09-28 17:01:02 +0000683- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000684 after interpretation of symbolic links. On non-Unix systems, this
685 is an alias for os.path.abspath().
686
Tim Peters16a77ad2001-09-08 04:00:12 +0000687- operator.indexOf() (PySequence_Index() in the C API) now works with any
688 iterable object.
689
Guido van Rossum624c8af2001-09-18 15:21:04 +0000690- smtplib now supports various authentication and security features of
691 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000692
Guido van Rossum624c8af2001-09-18 15:21:04 +0000693- hmac: a new module implementing keyed hashing for message
694 authentication.
695
696- mimetypes now recognizes more extensions and file types. At the
697 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000698
Guido van Rossum624c8af2001-09-18 15:21:04 +0000699- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000700 Python 2.2 bytecode generation. It has also been promoted from a
701 Tool to a standard library package. (Tools/compiler still exists as
702 a sample driver.)
703
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000704Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000705
Tim Petersb07352e2001-09-08 01:25:47 +0000706Build
707
Guido van Rossum624c8af2001-09-18 15:21:04 +0000708- Large file support (LFS) is now automatic when the platform supports
709 it; no more manual configuration tweaks are needed. On Linux, at
710 least, it's possible to have a system whose C library supports large
711 files but whose kernel doesn't; in this case, large file support is
712 still enabled but doesn't do you any good unless you upgrade your
713 kernel or share your Python executable with another system whose
714 kernel has large file support.
715
716- The configure script now supplies plausible defaults in a
717 cross-compilation environment. This doesn't mean that the supplied
718 values are always correct, or that cross-compilation now works
719 flawlessly -- but it's a first step (and it shuts up most of
720 autoconf's warnings about AC_TRY_RUN).
721
722- The Unix build is now a bit less chatty, courtesy of the parser
723 generator. The build is completely silent (except for errors) when
724 using "make -s", thanks to a -q option to setup.py.
725
Tim Petersb07352e2001-09-08 01:25:47 +0000726C API
727
Guido van Rossum624c8af2001-09-18 15:21:04 +0000728- The "structmember" API now supports some new flag bits to deny read
729 and/or write access to attributes in restricted execution mode.
730
Tim Petersb07352e2001-09-08 01:25:47 +0000731New platforms
732
Guido van Rossum624c8af2001-09-18 15:21:04 +0000733- Compaq's iPAQ handheld, running the "familiar" Linux distribution
734 (http://familiar.handhelds.org).
735
Tim Petersb07352e2001-09-08 01:25:47 +0000736Tests
737
Tim Peters8a9c2842001-09-22 21:30:22 +0000738- The "classic" standard tests, which work by comparing stdout to
739 an expected-output file under Lib/test/output/, no longer stop at
740 the first mismatch. Instead the test is run to completion, and a
741 variant of ndiff-style comparison is used to report all differences.
742 This is much easier to understand than the previous style of reporting.
743
744- The unittest-based standard tests now use regrtest's test_main()
745 convention, instead of running as a side-effect of merely being
746 imported. This allows these tests to be run in more natural and
747 flexible ways as unittests, outside the regrtest framework.
748
749- regrtest.py is much better integrated with unittest and doctest now,
750 especially in regard to reporting errors.
751
Tim Petersb07352e2001-09-08 01:25:47 +0000752Windows
753
Guido van Rossum624c8af2001-09-18 15:21:04 +0000754- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000755 that support it (NTFS under Windows 2000). See "What's New in
756 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000757
Tim Petersb07352e2001-09-08 01:25:47 +0000758
Tim Petersedc99312001-08-22 21:36:50 +0000759What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000760Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000761===========================
762
763Core
764
Tim Peters9fffa3e2001-09-04 05:14:19 +0000765- Conversion of long to float now raises OverflowError if the long is too
766 big to represent as a C double.
767
Tim Peters32f453e2001-09-03 08:35:41 +0000768- The 3-argument builtin pow() no longer allows a third non-None argument
769 if either of the first two arguments is a float, or if both are of
770 integer types and the second argument is negative (in which latter case
771 the arguments are converted to float, so this is really the same
772 restriction).
773
Tim Peters5d2b77c2001-09-03 05:47:38 +0000774- The builtin dir() now returns more information, and sometimes much
775 more, generally naming all attributes of an object, and all attributes
776 reachable from the object via its class, and from its class's base
777 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
778 an empty list. In 2.2a3,
779
780 >>> dir([])
781 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
782 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
783 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
784 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
785 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
786 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
787 'reverse', 'sort']
788
789 dir(module) continues to return only the module's attributes, though.
790
Tim Petersbdee63f2001-09-02 03:40:59 +0000791- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000792 than raising OverflowError. This is a partial implementation of PEP
793 237. You can use -Wdefault::OverflowWarning to enable a warning for
794 this situation, and -Werror::OverflowWarning to revert to the old
795 OverflowError exception.
796
Guido van Rossum61c345f2001-09-04 03:26:15 +0000797- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000798 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000799 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
800 -Qold, meaning the / operator has its classic meaning and no
801 warnings are issued. Using -Qwarn issues a run-time warning about
802 all uses of classic division for int and long arguments; -Qwarnall
803 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +0000804 (for use with fixdiv.py).
805 [Note: the remainder of this paragraph (preserved below) became
806 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
807 <obsolete>
808 Using -Qnew is questionable; it turns on new division by default, but
809 only in the __main__ module. You can usefully combine -Qwarn or
810 -Qwarnall and -Qnew: this gives the __main__ module new division, and
811 warns about classic division everywhere else.
812 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +0000813
Tim Petersbdee63f2001-09-02 03:40:59 +0000814- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000815 long, float, str, unicode, and tuple. (The types complex, list and
816 dictionary can also be subclassed; this was introduced earlier.)
817 Note that restrictions apply when subclassing immutable built-in
818 types: you can only affect the value of the instance by overloading
819 __new__. You can add mutable attributes, and the subclass instances
820 will have a __dict__ attribute, but you cannot change the "value"
821 (as implemented by the base class) of an immutable subclass instance
822 once it is created.
823
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000824- The dictionary constructor now takes an optional argument, a
825 mapping-like object, and initializes the dictionary from its
826 (key, value) pairs.
827
Tim Petersbdee63f2001-09-02 03:40:59 +0000828- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000829 "cooperative super calls" in a multiple inheritance setting. For an
830 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
831
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000832- A new built-in type, property, has been added. This enables the
833 creation of "properties". These are attributes implemented by
834 getter and setter functions (or only one of these for read-only or
835 write-only attributes), without the need to override __getattr__.
836 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000837
Tim Petersbdee63f2001-09-02 03:40:59 +0000838- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000839 liberalized, to allow leading zeroes. Examples of literals now
840 legal that were SyntaxErrors before:
841
842 00.0 0e3 0100j 07.5 00000000000000000008.
843
Tim Petersbdee63f2001-09-02 03:40:59 +0000844- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000845 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
846
Tim Petersedc99312001-08-22 21:36:50 +0000847Library
848
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000849- telnetlib includes symbolic names for the options, and support for
850 setting an option negotiation callback.
851
Tim Petersa40c7932001-09-05 22:36:56 +0000852- The new C standard no longer requires that math libraries set errno to
853 ERANGE on overflow. For platform libraries that exploit this new
854 freedom, Python's overflow-checking was wholly broken. A new overflow-
855 checking scheme attempts to repair that, but may not be reliable on all
856 platforms (C doesn't seem to provide anything both useful and portable
857 in this area anymore).
858
Martin v. Löwis44f86962001-09-05 13:44:54 +0000859- Asynchronous timeout actions are available through the new class
860 threading.Timer.
861
Tim Peters78526162001-09-05 00:53:45 +0000862- math.log and math.log10 now return sensible results for even huge
863 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
864
Tim Petersbdee63f2001-09-02 03:40:59 +0000865- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000866 currently held. See the docs for the imp module.
867
Tim Petersbdee63f2001-09-02 03:40:59 +0000868- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000869 dumps containing ints written on platforms where Python ints are 8 bytes.
870 When read on a box where Python ints are 4 bytes, such values are
871 converted to Python longs.
872
Tim Petersbdee63f2001-09-02 03:40:59 +0000873- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000874 code objects is no longer allowed. This plugs a security hole.
875
Steve Purcell6091cd62001-09-06 16:05:17 +0000876- unittest.TestResult instances no longer store references to tracebacks
877 generated by test failures. This prevents unexpected dangling references
878 to objects that should be garbage collected between tests.
879
Tim Petersedc99312001-08-22 21:36:50 +0000880Tools
881
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000882- Tools/scripts/fixdiv.py has been added which can be used to fix
883 division operators as per PEP 238.
884
Tim Petersedc99312001-08-22 21:36:50 +0000885Build
886
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000887- If you are an adventurous person using Mac OS X you may want to look at
888 Mac/OSX. There is a Makefile there that will build Python as a real Mac
889 application, which can be used for experimenting with Carbon or Cocoa.
890 Discussion of this on pythonmac-sig, please.
891
Tim Peters7eea37e2001-09-04 22:08:56 +0000892C API
893
894- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000895
Tim Peters9fffa3e2001-09-04 05:14:19 +0000896- Note that PyLong_AsDouble can fail! This has always been true, but no
897 callers checked for it. It's more likely to fail now, because overflow
898 errors are properly detected now. The proper way to check:
899
900 double x = PyLong_AsDouble(some_long_object);
901 if (x == -1.0 && PyErr_Occurred()) {
902 /* The conversion failed. */
903 }
904
Tim Petersbdee63f2001-09-02 03:40:59 +0000905- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000906 compile but will not participate in GC. To upgrade an extension
907 module:
908
909 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000910
Neil Schemenauer4042c692001-08-30 15:38:01 +0000911 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
912 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000913
Neil Schemenauer4042c692001-08-30 15:38:01 +0000914 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
915 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000916
Neil Schemenauer4042c692001-08-30 15:38:01 +0000917 - remove PyGC_HEAD_SIZE from object size calculations
918
919 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
920
Tim Petersbdee63f2001-09-02 03:40:59 +0000921- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000922 These can be used safely to construct string objects from a
923 sprintf-style format string (similar to the format string supported
924 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000925
Tim Petersedc99312001-08-22 21:36:50 +0000926New platforms
927
Tim Petersb7da0902001-09-02 23:01:43 +0000928- Stephen Hansen contributed patches sufficient to get a clean compile
929 under Borland C (Windows), but he reports problems running it and ran
930 out of time to complete the port. Volunteers? Expect a MemoryError
931 when importing the types module; this is probably shallow, and
932 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000933
Tim Petersedc99312001-08-22 21:36:50 +0000934Tests
935
936Windows
937
Tim Peters6e13a562001-09-06 00:32:15 +0000938- Large file support is now enabled on Win32 platforms as well as on
939 Win64. This means that, for example, you can use f.tell() and f.seek()
940 to manipulate files larger than 2 gigabytes (provided you have enough
941 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000942 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
943 filesize limit, and large file support makes no difference there.
944 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
945 NTFS has no practical limit on file size, and files of any size can be
946 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000947
Tim Petersbdee63f2001-09-02 03:40:59 +0000948- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000949 points to command.com (patch from Brian Quinlan).
950
Tim Petersedc99312001-08-22 21:36:50 +0000951
Tim Peters20f51a72001-07-21 02:31:40 +0000952What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000953Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000954===========================
955
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000956Build
957
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000958- Tim Peters developed a brand new Windows installer using Wise 8.1,
959 generously donated to us by Wise Solutions.
960
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000961- configure supports a new option --enable-unicode, with the values
962 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
963 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000964
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000965- A new configure option --enable-framework builds a Mac OS X framework,
966 which "make frameworkinstall" will install. This provides a starting
967 point for more mac-like functionality, join pythonmac-sig@python.org
968 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000969
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000970- The NeXT platform is no longer supported.
971
972- The `new' module is now statically linked.
973
Tim Peters0afb6092001-08-15 06:06:44 +0000974Tools
975
976- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000977 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000978 the module docstring for details.
979
Tim Peters20f51a72001-07-21 02:31:40 +0000980Tests
981
Tim Peters5e824c32001-08-12 22:25:01 +0000982- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000983 platforms, allowing to give clearer test result output. regrtest
984 also has optional --use/-u switch to run normally disabled tests
985 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000986
Tim Peters20f51a72001-07-21 02:31:40 +0000987- Several new tests in the standard test suite, with special thanks to
988 Nick Mathewson.
989
990Core
991
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000992- The floor division operator // has been added as outlined in PEP
993 238. The / operator still provides classic division (and will until
994 Python 3.0) unless "from __future__ import division" is included, in
995 which case the / operator will provide true division. The operator
996 module provides truediv() and floordiv() functions. Augmented
997 assignment variants are included, as are the equivalent overloadable
998 methods and C API methods. See the PEP for a full discussion:
999 <http://python.sf.net/peps/pep-0238.html>
1000
Tim Peters6cd6a822001-08-17 22:11:27 +00001001- Future statements are now effective in simulated interactive shells
1002 (like IDLE). This should "just work" by magic, but read Michael
1003 Hudson's "Future statements in simulated shells" PEP 264 for full
1004 details: <http://python.sf.net/peps/pep-0264.html>.
1005
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001006- The type/class unification (PEP 252-253) was integrated into the
1007 trunk and is not so tentative any more (the exact specification of
1008 some features is still tentative). A lot of work has done on fixing
1009 bugs and adding robustness and features (performance still has to
1010 come a long way).
1011
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001012- Warnings about a mismatch in the Python API during extension import
1013 now use the Python warning framework (which makes it possible to
1014 write filters for these warnings).
1015
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001016- A function's __dict__ (aka func_dict) will now always be a
1017 dictionary. It used to be possible to delete it or set it to None,
1018 but now both actions raise TypeErrors. It is still legal to set it
1019 to a dictionary object. Getting func.__dict__ before any attributes
1020 have been assigned now returns an empty dictionary instead of None.
1021
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001022- A new command line option, -E, was added which disables the use of
1023 all environment variables, or at least those that are specifically
1024 significant to Python. Usually those have a name starting with
1025 "PYTHON". This was used to fix a problem where the tests fail if
1026 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1027 older distribution.
1028
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001029Library
1030
Tim Peters5e824c32001-08-12 22:25:01 +00001031- New class Differ and new functions ndiff() and restore() in difflib.py.
1032 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001033 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001034
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001035- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1036 value using the minimal quoting required for the value; more
1037 reliable than using xml.sax.saxutils.escape() for attribute values.
1038
1039- Readline completion support for cmd.Cmd was added.
1040
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001041- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1042
1043- Added function threading.BoundedSemaphore()
1044
1045- Added Ka-Ping Yee's cgitb.py module.
1046
1047- The `new' module now exposes the CO_xxx flags.
1048
Martin v. Löwis560da622001-11-24 09:24:51 +00001049- The gc module offers the get_referents function.
1050
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001051New platforms
1052
1053C API
1054
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001055- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1056 which provide a cross-platform implementations for the
1057 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1058 the standard sprintf() and vsprintf() C lib APIs, these versions
1059 apply bounds checking on the used buffer which enhances protection
1060 against buffer overruns.
1061
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001062- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001063 and extensions using different Unicode widths is rendered next to
1064 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001065 will result in an ImportError. Unicode extensions writers must make
1066 sure to check the Unicode width compatibility in their extensions by
1067 using at least one of the mangled Unicode APIs in the extension.
1068
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001069- Two new flags METH_NOARGS and METH_O are available in method definition
1070 tables to simplify implementation of methods with no arguments and a
1071 single untyped argument. Calling such methods is more efficient than
1072 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1073 deprecated.
1074
Tim Petersc1731372001-08-04 08:12:36 +00001075Windows
1076
1077- "import module" now compiles module.pyw if it exists and nothing else
1078 relevant is found.
1079
Tim Peters20f51a72001-07-21 02:31:40 +00001080
Guido van Rossum55a78992001-07-17 17:22:32 +00001081What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001082Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001083===========================
1084
1085Core
Tim Petersa814db52001-05-14 07:05:58 +00001086
Tim Peters6d6c1a32001-08-02 04:15:00 +00001087- TENTATIVELY, a large amount of code implementing much of what's
1088 described in PEP 252 (Making Types Look More Like Classes) and PEP
1089 253 (Subtyping Built-in Types) was added. This will be released
1090 with Python 2.2a1. Documentation will be provided separately
1091 through http://www.python.org/2.2/. The purpose of releasing this
1092 with Python 2.2a1 is to test backwards compatibility. It is
1093 possible, though not likely, that a decision is made not to release
1094 this code as part of 2.2 final, if any serious backwards
1095 incompapatibilities are found during alpha testing that cannot be
1096 repaired.
1097
Guido van Rossum55a78992001-07-17 17:22:32 +00001098- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001099 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001100 more 'yield' statements. See PEP 255. Since this adds a new
1101 keyword to the language, this feature must be enabled by including a
1102 future statement: "from __future__ import generators" (see PEP 236).
1103 Generators will become a standard feature in a future release
1104 (probably 2.3). Without this future statement, 'yield' remains an
1105 ordinary identifier, but a warning is issued each time it is used.
1106 (These warnings currently don't conform to the warnings framework of
1107 PEP 230; we intend to fix this in 2.2a2.)
1108
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001109- The UTF-16 codec was modified to be more RFC compliant. It will now
1110 only remove BOM characters at the start of the string and then
1111 only if running in native mode (UTF-16-LE and -BE won't remove a
1112 leading BMO character).
1113
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001114- Strings now have a new method .decode() to complement the already
1115 existing .encode() method. These two methods provide direct access
1116 to the corresponding decoders and encoders of the registered codecs.
1117
1118 To enhance the usability of the .encode() method, the special
1119 casing of Unicode object return values was dropped (Unicode objects
1120 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001121
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001122 Both methods will now return whatever the codec in charge of the
1123 requested encoding returns as object, e.g. Unicode codecs will
1124 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1125 will return u"äöü"). This enables codec writer to create codecs
1126 for various simple to use conversions.
1127
1128 New codecs were added to demonstrate these new features (the .encode()
1129 and .decode() columns indicate the type of the returned objects):
1130
1131 Name | .encode() | .decode() | Description
1132 ----------------------------------------------------------------------
1133 uu | string | string | UU codec (e.g. for email)
1134 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001135 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001136 zlib | string | string | zlib compression
1137 hex | string | string | 2-byte hex codec
1138 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1139
Mark Hammond2a0af792001-05-14 03:09:36 +00001140- Some operating systems now support the concept of a default Unicode
1141 encoding for file system operations. Notably, Windows supports 'mbcs'
1142 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001143 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001144 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001145
1146 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001147 functions that return filenames (such as os.listdir()) to return Python
1148 string objects pre-encoded using the default file system encoding for
1149 the platform. As this encoding is likely to be different from Python's
1150 default encoding, converting this name to a Unicode object before passing
1151 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001152 would attempt to use its default encoding (generally ASCII) rather than
1153 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001154
Tim Petersa814db52001-05-14 07:05:58 +00001155 In general, this change simply removes surprises when working with
1156 Unicode and the file system, making these operations work as you expect,
1157 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001158 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001159
Tim Peters61dff2b2001-05-08 15:43:37 +00001160- Float (and complex) literals in source code were evaluated to full
1161 precision only when running from a .py file; the same code loaded from a
1162 .pyc (or .pyo) file could suffer numeric differences starting at about the
1163 12th significant decimal digit. For example, on a machine with IEEE-754
1164 floating arithmetic,
1165
1166 x = 9007199254740992.0
1167 print long(x)
1168
1169 printed 9007199254740992 if run directly from .py, but 9007199254740000
1170 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1171 str(float) instead of repr(float) when building code objects. marshal
1172 now uses repr(float) instead, which should reproduce floats to full
1173 machine precision (assuming the platform C float<->string I/O conversion
1174 functions are of good quality).
1175
1176 This may cause floating-point results to change in some cases, and
1177 usually for the better, but may also cause numerically unstable
1178 algorithms to break.
1179
Tim Peters2f228e72001-05-13 00:19:31 +00001180- The implementation of dicts suffers fewer collisions, which has speed
1181 benefits. However, the order in which dict entries appear in dict.keys(),
1182 dict.values() and dict.items() may differ from previous releases for a
1183 given dict. Nothing is defined about this order, so no program should
1184 rely on it. Nevertheless, it's easy to write test cases that rely on the
1185 order by accident, typically because of printing the str() or repr() of a
1186 dict to an "expected results" file. See Lib/test/test_support.py's new
1187 sortdict(dict) function for a simple way to display a dict in sorted
1188 order.
1189
Tim Peters7a3bfc32001-06-12 01:22:22 +00001190- Many other small changes to dicts were made, resulting in faster
1191 operation along the most common code paths.
1192
Guido van Rossum10315822001-05-01 20:54:30 +00001193- Dictionary objects now support the "in" operator: "x in dict" means
1194 the same as dict.has_key(x).
1195
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001196- The update() method of dictionaries now accepts generic mapping
1197 objects. Specifically the argument object must support the .keys()
1198 and __getitem__() methods. This allows you to say, for example,
1199 {}.update(UserDict())
1200
Guido van Rossum10315822001-05-01 20:54:30 +00001201- Iterators were added; this is a generalized way of providing values
1202 to a for loop. See PEP 234. There's a new built-in function iter()
1203 to return an iterator. There's a new protocol to get the next value
1204 from an iterator using the next() method (in Python) or the
1205 tp_iternext slot (in C). There's a new protocol to get iterators
1206 using the __iter__() method (in Python) or the tp_iter slot (in C).
1207 Iterating (i.e. a for loop) over a dictionary generates its keys.
1208 Iterating over a file generates its lines.
1209
Tim Petersf553f892001-05-01 20:45:31 +00001210- The following functions were generalized to work nicely with iterator
1211 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001212 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001213 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1214 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001215 join() method of strings
1216 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001217 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1218 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001219 right-hand side of assignment statements with multiple targets, such as
1220 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001221
Tim Petersd85e1022001-05-11 21:51:48 +00001222- Accessing module attributes is significantly faster (for example,
1223 random.random or os.path or yourPythonModule.yourAttribute).
1224
Tim Peterse63415e2001-05-08 04:38:29 +00001225- Comparing dictionary objects via == and != is faster, and now works even
1226 if the keys and values don't support comparisons other than ==.
1227
Tim Peters95bf9392001-05-10 08:32:44 +00001228- Comparing dictionaries in ways other than == and != is slower: there were
1229 insecurities in the dict comparison implementation that could cause Python
1230 to crash if the element comparison routines for the dict keys and/or
1231 values mutated the dicts. Making the code bulletproof slowed it down.
1232
Tim Peterseb28ef22001-06-02 05:27:19 +00001233- Collisions in dicts are resolved via a new approach, which can help
1234 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001235 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001236 faster now. Thanks to Christian Tismer for pointing out the cause and
1237 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001238
Tim Peters52e155e2001-06-16 05:42:57 +00001239- repr() is much faster for large containers (dict, list, tuple).
1240
1241
Tim Petersa814db52001-05-14 07:05:58 +00001242Library
1243
Fred Drake960fdf92001-07-20 18:38:26 +00001244- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1245 were added to the string module. These a locale-indenpendent
1246 constants, unlike letters, lowercase, and uppercase. These are now
1247 use in appropriate locations in the standard library.
1248
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001249- The flags used in dlopen calls can now be configured using
1250 sys.setdlopenflags and queried using sys.getdlopenflags.
1251
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001252- Fredrik Lundh's xmlrpclib is now a standard library module. This
1253 provides full client-side XML-RPC support. In addition,
1254 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1255 one asyncore-based). Thanks to Eric Raymond for the documentation.
1256
Guido van Rossum643d3912001-07-05 14:46:25 +00001257- The xrange() object is simplified: it no longer supports slicing,
1258 repetition, comparisons, efficient 'in' checking, the tolist()
1259 method, or the start, stop and step attributes. See PEP 260.
1260
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001261- A new function fnmatch.filter to filter lists of file names was added.
1262
Barry Warsawffd674d2001-05-22 16:00:10 +00001263- calendar.py uses month and day names based on the current locale.
1264
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001265- strop is now *really* obsolete (this was announced before with 1.6),
1266 and issues DeprecationWarning when used (except for the four items
1267 that are still imported into string.py).
1268
Tim Petersa814db52001-05-14 07:05:58 +00001269- Cookie.py now sorts key+value pairs by key in output strings.
1270
1271- pprint.isrecursive(object) didn't correctly identify recursive objects.
1272 Now it does.
1273
Tim Peters95b3f782001-05-14 18:39:41 +00001274- pprint functions now much faster for large containers (tuple, list, dict).
1275
Tim Peters7b9542a2001-06-10 23:40:19 +00001276- New 'q' and 'Q' format codes in the struct module, corresponding to C
1277 types "long long" and "unsigned long long" (on Windows, __int64). In
1278 native mode, these can be used only when the platform C compiler supports
1279 these types (when HAVE_LONG_LONG is #define'd by the Python config
1280 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001281 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1282 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001283
Guido van Rossum83213cc2001-06-12 16:48:52 +00001284- The site module installs a new built-in function 'help' that invokes
1285 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1286 it displays a message reminding the user to use 'help()' or
1287 'help(object)'.
1288
Tim Petersa814db52001-05-14 07:05:58 +00001289Tests
1290
1291- New test_mutants.py runs dict comparisons where the key and value
1292 comparison operators mutute the dicts randomly during comparison. This
1293 rapidly causes Python to crash under earlier releases (not for the faint
1294 of heart: it can also cause Win9x to freeze or reboot!).
1295
1296- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001297 pprint.isreadable() return sensible results. Also verifies that simple
1298 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001299
Tim Peters4324aa32001-05-28 22:30:08 +00001300C API
1301
1302- Removed the unused last_is_sticky argument from the internal
1303 _PyTuple_Resize(). If this affects you, you were cheating.
1304
1305
Guido van Rossum55a78992001-07-17 17:22:32 +00001306======================================================================
1307
1308
Guido van Rossumffe13be2001-04-16 18:46:45 +00001309What's New in Python 2.1 (final)?
1310=================================
1311
1312We only changed a few things since the last release candidate, all in
1313Python library code:
1314
1315- A bug in the locale module was fixed that affected locales which
1316 define no grouping for numeric formatting.
1317
1318- A few bugs in the weakref module's implementations of weak
1319 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1320 and the test suite was updated to check for these bugs.
1321
1322- An old bug in the os.path.walk() function (introduced in Python
1323 2.0!) was fixed: a non-existent file would cause an exception
1324 instead of being ignored.
1325
1326- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1327 PyChecker.
1328
1329
Guido van Rossum5b08f132001-04-16 02:05:23 +00001330What's New in Python 2.1c2?
1331===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001332
Guido van Rossum5b08f132001-04-16 02:05:23 +00001333A flurry of small changes, and one showstopper fixed in the nick of
1334time made it necessary to release another release candidate. The list
1335here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001336
Guido van Rossum5b08f132001-04-16 02:05:23 +00001337Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001338
Guido van Rossum5b08f132001-04-16 02:05:23 +00001339- Tim discovered a nasty bug in the dictionary code, caused by
1340 PyDict_Next() calling dict_resize(), and the GC code's use of
1341 PyDict_Next() violating an assumption in dict_items(). This was
1342 fixed with considerable amounts of band-aid, but the net effect is a
1343 saner and more robust implementation.
1344
1345- Made a bunch of symbols static that were accidentally global.
1346
1347Build and Ports
1348
1349- The setup.py script didn't check for a new enough version of zlib
1350 (1.1.3 is needed). Now it does.
1351
1352- Changed "make clean" target to also remove shared libraries.
1353
1354- Added a more general warning about the SGI Irix optimizer to README.
1355
1356Library
1357
1358- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1359 omitted the slash between host and file.html.
1360
1361- The mailbox module's _Mailbox class contained a completely broken
1362 and undocumented seek() method. Ripped it out.
1363
1364- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1365 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1366
1367- Fixed a few last-minute bugs in unittest.
1368
1369Extensions
1370
1371- Reverted the patch to the OpenSSL code in socketmodule.c to support
1372 RAND_status() and the EGD, and the subsequent patch that tried to
1373 fix it for pre-0.9.5 versions; the problem with the patch is that on
1374 some systems it issues a warning whenever socket is imported, and
1375 that's unacceptable.
1376
1377Tests
1378
1379- Fixed the pickle tests to work with "import test.test_pickle".
1380
1381- Tweaked test_locale.py to actually run the test Windows.
1382
1383- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1384 not "wb" (which is not a valid mode at all).
1385
1386- Fix pstats browser crashes. Import readline if it exists to make
1387 the user interface nicer.
1388
1389- Add "import thread" to the top of test modules that import the
1390 threading module (test_asynchat and test_threadedtempfile). This
1391 prevents test failures caused by a broken threading module resulting
1392 from a previously caught failed import.
1393
1394- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1395 needed on some platforms (e.g. Solaris 8) when the tests are run
1396 twice in succession.
1397
1398- Skip rather than fail test_sunaudiodev if no audio device is found.
1399
1400
1401What's New in Python 2.1c1?
1402===========================
1403
1404This list was significantly updated when 2.1c2 was released; the 2.1c1
1405release didn't mention most changes that were actually part of 2.1c1:
1406
1407Legal
1408
1409- Copyright was assigned to the Python Software Foundation (PSF) and a
1410 PSF license (very similar to the CNRI license) was added.
1411
1412- The CNRI copyright notice was updated to include 2001.
1413
1414Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001415
Guido van Rossumc9932722001-04-12 02:31:27 +00001416- After a public outcry, assignment to __debug__ is no longer illegal;
1417 instead, a warning is issued. It will become illegal in 2.2.
1418
Guido van Rossum5b08f132001-04-16 02:05:23 +00001419- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1420 "%#x" now always prepends "0x", even if the value is zero.
1421
1422- Fixed some nits in the bytecode compiler.
1423
1424- Fixed core dumps when calling certain kinds of non-functions.
1425
1426- Fixed various core dumps caused by reference count bugs.
1427
1428Build and Ports
1429
1430- Use INSTALL_SCRIPT to install script files.
1431
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001432- New port: SCO Unixware 7, by Billy G. Allie.
1433
Guido van Rossum5b08f132001-04-16 02:05:23 +00001434- Updated RISCOS port.
1435
1436- Updated BeOS port and notes.
1437
1438- Various other porting problems resolved.
1439
1440Library
1441
1442- The TERMIOS and SOCKET modules are now truly obsolete and
1443 unnecessary. Their symbols are incorporated in the termios and
1444 socket modules.
1445
1446- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1447 better tests for pickling.
1448
1449- threading: make Condition.wait() robust against KeyboardInterrupt.
1450
1451- zipfile: add support to zipfile to support opening an archive
1452 represented by an open file rather than a file name. Fix bug where
1453 the archive was not properly closed. Fixed a bug in this bugfix
1454 where flush() was called for a read-only file.
1455
1456- imputil: added an uninstall() method to the ImportManager.
1457
1458- Canvas: fixed bugs in lower() and tkraise() methods.
1459
1460- SocketServer: API change (added overridable close_request() method)
1461 so that the TCP server can explicitly close the request.
1462
1463- pstats: Eric Raymond added a simple interactive statistics browser,
1464 invoked when the module is run as a script.
1465
1466- locale: fixed a problem in format().
1467
1468- webbrowser: made it work when the BROWSER environment variable has a
1469 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1470 KDE 2. Fixed some other nits.
1471
1472- unittest: changes to allow using a different exception than
1473 AssertionError, and added a few more function aliases. Some other
1474 small changes.
1475
1476- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1477
1478- asynchat: fixed a critical bug in asynchat that slipped through the
1479 2.1b2 release. Fixed another rare bug.
1480
1481- Fix some unqualified except: clauses (always a bad code example).
1482
1483XML
1484
1485- pyexpat: new API get_version_string().
1486
1487- Fixed some minidom bugs.
1488
1489Extensions
1490
1491- Fixed a core dump in _weakref. Removed the weakref.mapping()
1492 function (it adds nothing to the API).
1493
1494- Rationalized the use of header files in the readline module, to make
1495 it compile (albeit with some warnings) with the very recent readline
1496 4.2, without breaking for earlier versions.
1497
1498- Hopefully fixed a buffering problem in linuxaudiodev.
1499
1500- Attempted a fix to make the OpenSSL support in the socket module
1501 work again with pre-0.9.5 versions of OpenSSL.
1502
1503Tests
1504
1505- Added a test case for asynchat and asyncore.
1506
1507- Removed coupling between tests where one test failing could break
1508 another.
1509
1510Tools
1511
1512- Ping added an interactive help browser to pydoc, fixed some nits
1513 in the rest of the pydoc code, and added some features to his
1514 inspect module.
1515
1516- An updated python-mode.el version 4.1 which integrates Ken
1517 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1518 much nicer in XEmacs and Emacs. When stepping through your program
1519 with pdb, in either the shell window or the *Python* window, the
1520 source file and line will be tracked by an arrow. Very cool!
1521
1522- IDLE: syntax warnings in interactive mode are changed into errors.
1523
1524- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001525 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001526
1527- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001528
Barry Warsaw11e89c72001-04-11 20:37:57 +00001529
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001530What's New in Python 2.1 beta 2?
1531================================
1532
Guido van Rossum053ae352001-03-22 14:17:21 +00001533(Unlisted are many fixed bugs, more documentation, etc.)
1534
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001535Core language, builtins, and interpreter
1536
Guido van Rossum053ae352001-03-22 14:17:21 +00001537- The nested scopes work (enabled by "from __future__ import
1538 nested_scopes") is completed; in particular, the future now extends
1539 into code executed through exec, eval() and execfile(), and into the
1540 interactive interpreter.
1541
1542- When calling a base class method (e.g. BaseClass.__init__(self)),
1543 this is now allowed even if self is not strictly spoken a class
1544 instance (e.g. when using metaclasses or the Don Beaudry hook).
1545
1546- Slice objects are now comparable but not hashable; this prevents
1547 dict[:] from being accepted but meaningless.
1548
1549- Complex division is now calculated using less braindead algorithms.
1550 This doesn't change semantics except it's more likely to give useful
1551 results in extreme cases. Complex repr() now uses full precision
1552 like float repr().
1553
1554- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1555
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001556- It is illegal to assign to the name __debug__, which is set when the
1557 interpreter starts. It is effectively a compile-time constant.
1558
1559- A warning will be issued if a global statement for a variable
1560 follows a use or assignment of that variable.
1561
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001562Standard library
1563
Guido van Rossum053ae352001-03-22 14:17:21 +00001564- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1565 inspired by JUnit), is now part of the standard library. You now
1566 have a choice of two testing frameworks: unittest requires you to
1567 write testcases as separate code, doctest gathers them from
1568 docstrings. Both approaches have their advantages and
1569 disadvantages.
1570
1571- A new module Tix was added, which wraps the Tix extension library
1572 for Tk. With that module, it is not necessary to statically link
1573 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1574 require" command. See Demo/tix/.
1575
1576- tzparse.py is now obsolete.
1577
1578- In gzip.py, the seek() and tell() methods are removed -- they were
1579 non-functional anyway, and it's better if callers can test for their
1580 existence with hasattr().
1581
1582Python/C API
1583
1584- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1585 that's already in the dictionary during a PyDict_Next() iteration.
1586 This used to fail occasionally when a dictionary resize operation
1587 could be triggered that would rehash all the keys. All other
1588 modifications to the dictionary are still off-limits during a
1589 PyDict_Next() iteration!
1590
1591- New extended APIs related to passing compiler variables around.
1592
1593- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1594 implement isinstance() and issubclass().
1595
1596- Py_BuildValue() now has a "D" conversion to create a Python complex
1597 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001598
Fred Drake4e262a92001-03-22 18:26:47 +00001599- Extensions types which support weak references must now set the
1600 field allocated for the weak reference machinery to NULL themselves;
1601 this is done to avoid the cost of checking each object for having a
1602 weakly referencable type in PyObject_INIT(), since most types are
1603 not weakly referencable.
1604
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001605- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1606 free variables and cell variables to and from the frame's f_locals.
1607
1608- Variants of several functions defined in pythonrun.h have been added
1609 to support the nested_scopes future statement. The variants all end
1610 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1611 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1612 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001613 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001614
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001615Distutils
1616
1617- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1618 into the release tree.
1619
Tim Peters0e57abf2001-05-02 07:39:38 +00001620- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001621 (an uninstaller, more customization of the installer's display)
1622
1623- from Jack Jansen: added Mac-specific code to generate a dialog for
1624 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001625 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001626 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001627
1628- added 'platforms' and 'keywords' to the set of metadata that can be
1629 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001630
1631- applied patches from Jason Tishler to make the compiler class work with
1632 Cygwin.
1633
1634
Tim Peters2fe289a2001-03-01 22:19:38 +00001635What's New in Python 2.1 beta 1?
1636================================
Tim Petersd66595f2001-02-04 03:09:53 +00001637
1638Core language, builtins, and interpreter
1639
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001640- Following an outcry from the community about the amount of code
1641 broken by the nested scopes feature introduced in 2.1a2, we decided
1642 to make this feature optional, and to wait until Python 2.2 (or at
1643 least 6 months) to make it standard. The option can be enabled on a
1644 per-module basis by adding "from __future__ import nested_scopes" at
1645 the beginning of a module (before any other statements, but after
1646 comments and an optional docstring). See PEP 236 (Back to the
1647 __future__) for a description of the __future__ statement. PEP 227
1648 (Statically Nested Scopes) has been updated to reflect this change,
1649 and to clarify the semantics in a number of endcases.
1650
1651- The nested scopes code, when enabled, has been hardened, and most
1652 bugs and memory leaks in it have been fixed.
1653
1654- Compile-time warnings are now generated for a number of conditions
1655 that will break or change in meaning when nested scopes are enabled:
1656
1657 - Using "from...import *" or "exec" without in-clause in a function
1658 scope that also defines a lambda or nested function with one or
1659 more free (non-local) variables. The presence of the import* or
1660 bare exec makes it impossible for the compiler to determine the
1661 exact set of local variables in the outer scope, which makes it
1662 impossible to determine the bindings for free variables in the
1663 inner scope. To avoid the warning about import *, change it into
1664 an import of explicitly name object, or move the import* statement
1665 to the global scope; to avoid the warning about bare exec, use
1666 exec...in... (a good idea anyway -- there's a possibility that
1667 bare exec will be deprecated in the future).
1668
1669 - Use of a global variable in a nested scope with the same name as a
1670 local variable in a surrounding scope. This will change in
1671 meaning with nested scopes: the name in the inner scope will
1672 reference the variable in the outer scope rather than the global
1673 of the same name. To avoid the warning, either rename the outer
1674 variable, or use a global statement in the inner function.
1675
Neil Schemenauera35c6882001-02-27 04:45:05 +00001676- An optional object allocator has been included. This allocator is
1677 optimized for Python objects and should be faster and use less memory
1678 than the standard system allocator. It is not enabled by default
1679 because of possible thread safety problems. The allocator is only
1680 protected by the Python interpreter lock and it is possible that some
1681 extension modules require a thread safe allocator. The object
1682 allocator can be enabled by providing the "--with-pymalloc" option to
1683 configure.
1684
Tim Petersd66595f2001-02-04 03:09:53 +00001685Standard library
1686
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001687- pyexpat now detects the expat version if expat.h defines it. A
1688 number of additional handlers are provided, which are only available
1689 since expat 1.95. In addition, the methods SetParamEntityParsing and
1690 GetInputContext of Parser objects are available with 1.95.x
1691 only. Parser objects now provide the ordered_attributes and
1692 specified_attributes attributes. A new module expat.model was added,
1693 which offers a number of additional constants if 1.95.x is used.
1694
1695- xml.dom offers the new functions registerDOMImplementation and
1696 getDOMImplementation.
1697
1698- xml.dom.minidom offers a toprettyxml method. A number of DOM
1699 conformance issues have been resolved. In particular, Element now
1700 has an hasAttributes method, and the handling of namespaces was
1701 improved.
1702
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001703- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1704 getting information about live Python code, and pydoc.py, a module
1705 for interactively converting docstrings to HTML or text.
1706 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001707 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001708 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1709 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001710
Tim Peters1eff7962001-03-01 02:31:33 +00001711- New library module difflib.py, primarily packaging the SequenceMatcher
1712 class at the heart of the popular ndiff.py file-comparison tool.
1713
1714- doctest.py (a framework for verifying Python code examples in docstrings)
1715 is now part of the std library.
1716
Tim Petersd66595f2001-02-04 03:09:53 +00001717Windows changes
1718
Guido van Rossume3955a82001-03-02 14:05:59 +00001719- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1720 small GUI that lets you browse the module docstrings using your
1721 default web browser.
1722
Tim Peters1eff7962001-03-01 02:31:33 +00001723- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1724 Platforms) is implemented. See
1725
1726 http://python.sourceforge.net/peps/pep-0235.html
1727
1728 for full details, especially the "Current Lower-Left Semantics" section.
1729 The new Windows import rules are simpler than before:
1730
1731 A. If the PYTHONCASEOK environment variable exists, same as
1732 before: silently accept the first case-insensitive match of any
1733 kind; raise ImportError if none found.
1734
1735 B. Else search sys.path for the first case-sensitive match; raise
1736 ImportError if none found.
1737
1738 The same rules have been implented on other platforms with case-
1739 insensitive but case-preserving filesystems too (including Cygwin, and
1740 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001741
Tim Peters25a9ce32001-02-19 07:06:36 +00001742- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1743 what it's supposed to do (and does do under NT and 2000) via direct
1744 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001745 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001746 all Win9x systems before.
1747
Tim Peters1eff7962001-03-01 02:31:33 +00001748- Build: Subproject _test (effectively) renamed to _testcapi.
1749
Tim Peters2fe289a2001-03-01 22:19:38 +00001750New platforms
1751
1752- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1753 Thanks to Steven Majewski!
1754
1755- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1756 Tishler!
1757
Guido van Rossum9089b272001-03-02 06:49:50 +00001758- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1759 Schwertberger! See RISCOS/README for more information -- it seems
1760 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001761 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001762
Tim Peters25a9ce32001-02-19 07:06:36 +00001763
Tim Petersd7b5e882001-01-25 03:36:26 +00001764What's New in Python 2.1 alpha 2?
1765=================================
Tim Peters40ead762001-01-27 05:35:26 +00001766
Tim Petersd7b5e882001-01-25 03:36:26 +00001767Core language, builtins, and interpreter
1768
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001769- Scopes nest. If a name is used in a function or class, but is not
1770 local, the definition in the nearest enclosing function scope will
1771 be used. One consequence of this change is that lambda statements
1772 could reference variables in the namespaces where the lambda is
1773 defined. In some unusual cases, this change will break code.
1774
1775 In all previous version of Python, names were resolved in exactly
1776 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001777 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001778 function A is defined within a function B, the names bound in B are
1779 not visible in A. The new rules make names bound in B visible in A,
1780 unless A contains a name binding that hides the binding in B.
1781
1782 Section 4.1 of the reference manual describes the new scoping rules
1783 in detail. The test script in Lib/test/test_scope.py demonstrates
1784 some of the effects of the change.
1785
1786 The new rules will cause existing code to break if it defines nested
1787 functions where an outer function has local variables with the same
1788 name as globals or builtins used by the inner function. Example:
1789
1790 def munge(str):
1791 def helper(x):
1792 return str(x)
1793 if type(str) != type(''):
1794 str = helper(str)
1795 return str.strip()
1796
1797 Under the old rules, the name str in helper() is bound to the
1798 builtin function str(). Under the new rules, it will be bound to
1799 the argument named str and an error will occur when helper() is
1800 called.
1801
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001802- The compiler will report a SyntaxError if "from ... import *" occurs
1803 in a function or class scope. The language reference has documented
1804 that this case is illegal, but the compiler never checked for it.
1805 The recent introduction of nested scope makes the meaning of this
1806 form of name binding ambiguous. In a future release, the compiler
1807 may allow this form when there is no possibility of ambiguity.
1808
Tim Peters40ead762001-01-27 05:35:26 +00001809- repr(string) is easier to read, now using hex escapes instead of octal,
1810 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1811
1812 >>> "\texample \r\n" + chr(0) + chr(255)
1813 '\texample \r\n\x00\xff' # in 2.1
1814 '\011example \015\012\000\377' # in 2.0
1815
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001816- Functions are now compared and hashed by identity, not by value, since
1817 the func_code attribute is writable.
1818
Fred Drakefb9d7122001-02-01 20:00:40 +00001819- Weak references (PEP 205) have been added. This involves a few
1820 changes in the core, an extension module (_weakref), and a Python
1821 module (weakref). The weakref module is the public interface. It
1822 includes support for "explicit" weak references, proxy objects, and
1823 mappings with weakly held values.
1824
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001825- A 'continue' statement can now appear in a try block within the body
1826 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001827 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001828
Tim Petersd7b5e882001-01-25 03:36:26 +00001829Standard library
1830
Barry Warsaw30dbd142001-01-31 22:14:01 +00001831- mailbox.py now has a new class, PortableUnixMailbox which is
1832 identical to UnixMailbox but uses a more portable scheme for
1833 determining From_ separators. Also, the constructors for all the
1834 classes in this module have a new optional `factory' argument, which
1835 is a callable used when new message classes must be instantiated by
1836 the next() method.
1837
Tim Petersd7b5e882001-01-25 03:36:26 +00001838- random.py is now self-contained, and offers all the functionality of
1839 the now-deprecated whrandom.py. See the docs for details. random.py
1840 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001841 and restoring the internal state of the generator; and jumpahead(n),
1842 for quickly forcing the internal state to be the same as if n calls to
1843 random() had been made. The latter is particularly useful for multi-
1844 threaded programs, creating one instance of the random.Random() class for
1845 each thread, then using .jumpahead() to force each instance to use a
1846 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001847
Tim Peters0de88fc2001-02-01 04:59:18 +00001848- random.py's seed() function is new. For bit-for-bit compatibility with
1849 prior releases, use the whseed function instead. The new seed function
1850 addresses two problems: (1) The old function couldn't produce more than
1851 about 2**24 distinct internal states; the new one about 2**45 (the best
1852 that can be done in the Wichmann-Hill generator). (2) The old function
1853 sometimes produced identical internal states when passed distinct
1854 integers, and there was no simple way to predict when that would happen;
1855 the new one guarantees to produce distinct internal states for all
1856 arguments in [0, 27814431486576L).
1857
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001858- The socket module now supports raw packets on Linux. The socket
1859 family is AF_PACKET.
1860
Tim Peters9ea17ac2001-02-02 05:57:15 +00001861- test_capi.py is a start at running tests of the Python C API. The tests
1862 are implemented by the new Modules/_testmodule.c.
1863
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001864- A new extension module, _symtable, provides provisional access to the
1865 internal symbol table used by the Python compiler. A higher-level
1866 interface will be added on top of _symtable in a future release.
1867
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001868- Removed the obsolete soundex module.
1869
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001870- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1871 the isSameNode method; NamedNodeMap the get method.
1872
1873- xml.sax.expatreader supports the lexical handler property; it
1874 generates comment, startCDATA, and endCDATA events.
1875
Tim Petersee826f82001-01-31 19:39:44 +00001876Windows changes
1877
1878- Build procedure: the zlib project is built in a different way that
1879 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001880 the zlib binary used. See PCbuild\readme.txt for details. Your old
1881 zlib-related directories can be deleted; you'll need to download fresh
1882 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001883
Tim Peters9ea17ac2001-02-02 05:57:15 +00001884- Build: New subproject _test for the benefit of test_capi.py (see above).
1885
Tim Petersb16c56f2001-02-02 21:24:51 +00001886- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1887 interface to some Python compiler internals).
1888
1889- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001890 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001891
Tim Petersa3a3a032000-11-30 05:22:44 +00001892What's New in Python 2.1 alpha 1?
1893=================================
1894
1895Core language, builtins, and interpreter
1896
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001897- There is a new Unicode companion to the PyObject_Str() API
1898 called PyObject_Unicode(). It behaves in the same way as the
1899 former, but assures that the returned value is an Unicode object
1900 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001901
Guido van Rossumf98eda02001-01-17 15:54:45 +00001902- The comparison operators support "rich comparison overloading" (PEP
1903 207). C extension types can provide a rich comparison function in
1904 the new tp_richcompare slot in the type object. The cmp() function
1905 and the C function PyObject_Compare() first try the new rich
1906 comparison operators before trying the old 3-way comparison. There
1907 is also a new C API PyObject_RichCompare() (which also falls back on
1908 the old 3-way comparison, but does not constrain the outcome of the
1909 rich comparison to a Boolean result).
1910
1911 The rich comparison function takes two objects (at least one of
1912 which is guaranteed to have the type that provided the function) and
1913 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1914 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1915 object, which may be NotImplemented (in which case the tp_compare
1916 slot function is used as a fallback, if defined).
1917
1918 Classes can overload individual comparison operators by defining one
1919 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001920 __ge__. There are no explicit "reflected argument" versions of
1921 these; instead, __lt__ and __gt__ are each other's reflection,
1922 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1923 reflection (similar at the C level). No other implications are
1924 made; in particular, Python does not assume that == is the Boolean
1925 inverse of !=, or that < is the Boolean inverse of >=. This makes
1926 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001927
1928 Classes or types that want to implement (in)equality tests but not
1929 the ordering operators (i.e. unordered types) should implement ==
1930 and !=, and raise an error for the ordering operators.
1931
Guido van Rossuma88479f2001-01-18 14:28:08 +00001932 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001933 Boolean; e.g. a matrix type might want to return a matrix of bits
1934 for A < B, giving elementwise comparisons. Such types should ensure
1935 that any interpretation of their value in a Boolean context raises
1936 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1937 at the C level) to always raise an exception.
1938
Guido van Rossuma88479f2001-01-18 14:28:08 +00001939- Complex numbers use rich comparisons to define == and != but raise
1940 an exception for <, <=, > and >=. Unfortunately, this also means
1941 that cmp() of two complex numbers raises an exception when the two
1942 numbers differ. Since it is not mathematically meaningful to compare
1943 complex numbers except for equality, I hope that this doesn't break
1944 too much code.
1945
Tim Peters3389f192001-02-18 08:48:49 +00001946- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001947 not defined by the language, other than that it's arbitrary but
1948 consistent (see the Reference Manual). An implementation detail changed
1949 in 2.1a1 such that None now compares less than any other object. Code
1950 relying on this new behavior (like code that relied on the previous
1951 behavior) does so at its own risk.
1952
Barry Warsaw573b5412001-01-15 20:43:18 +00001953- Functions and methods now support getting and setting arbitrarily
1954 named attributes (PEP 232). Functions have a new __dict__
1955 (a.k.a. func_dict) which hold the function attributes. Methods get
1956 and set attributes on their underlying im_func. It is a TypeError
1957 to set an attribute on a bound method.
1958
Guido van Rossum051e3352001-01-15 19:11:10 +00001959- The xrange() object implementation has been improved so that
1960 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1961 limitation that in this case len(xrange(sys.maxint)) can't be
1962 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1963 work fine as long as the index i doesn't actually reach 2**31.
1964 (Python uses regular ints for sequence and string indices; fixing
1965 that is much more work.)
1966
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001967- Two changes to from...import:
1968
Guido van Rossumba381232001-02-03 15:06:40 +00001969 1) "from M import X" now works even if (after loading module M)
1970 sys.modules['M'] is not a real module; it's basically a getattr()
1971 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001972
1973 2) "from M import *" now looks for M.__all__ to decide which names to
1974 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1975 filters out names starting with '_' as before. Whether or not
1976 __all__ exists, there's no restriction on the type of M.
1977
Guido van Rossumf61f1662001-01-10 20:13:55 +00001978- File objects have a new method, xreadlines(). This is the fastest
1979 way to iterate over all lines in a file:
1980
1981 for line in file.xreadlines():
1982 ...do something to line...
1983
1984 See the xreadlines module (mentioned below) for how to do this for
1985 other file-like objects.
1986
1987- Even if you don't use file.xreadlines(), you may expect a speedup on
1988 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001989 quite a bit in platform-specific ways: on systems (like Linux) that
1990 support flockfile(), getc_unlocked(), and funlockfile(), those are
1991 used by default. On systems (like Windows) without getc_unlocked(),
1992 a complicated (but still thread-safe) method using fgets() is used by
1993 default.
1994
Tim Petersd52269b2001-01-25 06:23:18 +00001995 You can force use of the fgets() method by #define'ing
1996 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001997 getc_unlocked()).
1998
Tim Petersd52269b2001-01-25 06:23:18 +00001999 You can force fgets() not to be used by #define'ing
2000 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002001 test_bufio.py fails -- and let us know if it does!).
2002
2003- In addition, the fileinput module, while still slower than the other
2004 methods on most platforms, has been sped up too, by using
2005 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002006
2007- Support for run-time warnings has been added, including a new
2008 command line option (-W) to specify the disposition of warnings.
2009 See the description of the warnings module below.
2010
2011- Extensive changes have been made to the coercion code. This mostly
2012 affects extension modules (which can now implement mixed-type
2013 numerical operators without having to use coercion), but
2014 occasionally, in boundary cases the coercion semantics have changed
2015 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002016 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002017 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002018 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002019
Guido van Rossumf98eda02001-01-17 15:54:45 +00002020- In connection with the coercion changes, a new built-in singleton
2021 object, NotImplemented is defined. This can be returned for
2022 operations that wish to indicate they are not implemented for a
2023 particular combination of arguments. From C, this is
2024 Py_NotImplemented.
2025
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002026- The interpreter accepts now bytecode files on the command line even
2027 if they do not have a .pyc or .pyo extension. On Linux, after executing
2028
Martin v. Löwise214baa2001-02-04 22:37:56 +00002029import imp,sys,string
2030magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2031reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2032open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002033
2034 any byte code file can be used as an executable (i.e. as an argument
2035 to execve(2)).
2036
Tim Peters9940b802000-12-01 07:59:35 +00002037- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002038 character. In 1.6 and earlier, they never produced a sign,
2039 and raised an error if the value of the long was too large
2040 to fit in a Python int. In 2.0, they produced a sign if and
2041 only if too large to fit in an int. This was inconsistent
2042 across platforms (because the size of an int varies across
2043 platforms), and inconsistent with hex() and oct(). Example:
2044
2045 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002046 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002047 'ffffffbe' # in 2.0 and before, on 32-bit machines
2048 >>> hex(-0x42L)
2049 '-0x42L' # in all versions of Python
2050
Tim Peters9940b802000-12-01 07:59:35 +00002051 The behavior of %d formats for negative Python longs remains
2052 the same as in 2.0 (although in 1.6 and before, they raised
2053 an error if the long didn't fit in a Python int).
2054
2055 %u formats don't make sense for Python longs, but are allowed
2056 and treated the same as %d in 2.1. In 2.0, a negative long
2057 formatted via %u produced a sign if and only if too large to
2058 fit in an int. In 1.6 and earlier, a negative long formatted
2059 via %u raised an error if it was too big to fit in an int.
2060
Guido van Rossum3661d392000-12-12 22:10:31 +00002061- Dictionary objects have an odd new method, popitem(). This removes
2062 an arbitrary item from the dictionary and returns it (in the form of
2063 a (key, value) pair). This can be useful for algorithms that use a
2064 dictionary as a bag of "to do" items and repeatedly need to pick one
2065 item. Such algorithms normally end up running in quadratic time;
2066 using popitem() they can usually be made to run in linear time.
2067
Tim Peters36cdad12000-12-29 02:06:45 +00002068Standard library
2069
Thomas Woutersfe385252001-01-19 23:16:56 +00002070- In the time module, the time argument to the functions strftime,
2071 localtime, gmtime, asctime and ctime is now optional, defaulting to
2072 the current time (in the local timezone).
2073
Guido van Rossumda91f222001-01-15 16:36:08 +00002074- The ftplib module now defaults to passive mode, which is deemed a
2075 more useful default given that clients are often inside firewalls
2076 these days. Note that this could break if ftplib is used to connect
2077 to a *server* that is inside a firewall, from outside; this is
2078 expected to be a very rare situation. To fix that, you can call
2079 ftp.set_pasv(0).
2080
Martin v. Löwis10a27872001-01-13 09:54:41 +00002081- The module site now treats .pth files not only for path configuration,
2082 but also supports extensions to the initialization code: Lines starting
2083 with import are executed.
2084
Guido van Rossumf61f1662001-01-10 20:13:55 +00002085- There's a new module, warnings, which implements a mechanism for
2086 issuing and filtering warnings. There are some new built-in
2087 exceptions that serve as warning categories, and a new command line
2088 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2089 turns warnings into errors). warnings.warn(message[, category])
2090 issues a warning message; this can also be called from C as
2091 PyErr_Warn(category, message).
2092
2093- A new module xreadlines was added. This exports a single factory
2094 function, xreadlines(). The intention is that this code is the
2095 absolutely fastest way to iterate over all lines in an open
2096 file(-like) object:
2097
2098 import xreadlines
2099 for line in xreadlines.xreadlines(file):
2100 ...do something to line...
2101
2102 This is equivalent to the previous the speed record holder using
2103 file.readlines(sizehint). Note that if file is a real file object
2104 (as opposed to a file-like object), this is equivalent:
2105
2106 for line in file.xreadlines():
2107 ...do something to line...
2108
Tim Peters36cdad12000-12-29 02:06:45 +00002109- The bisect module has new functions bisect_left, insort_left,
2110 bisect_right and insort_right. The old names bisect and insort
2111 are now aliases for bisect_right and insort_right. XXX_right
2112 and XXX_left methods differ in what happens when the new element
2113 compares equal to one or more elements already in the list: the
2114 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002115 right. Code that doesn't care where equal elements end up should
2116 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002117
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002118- The new curses.panel module wraps the panel library that forms part
2119 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2120
Guido van Rossumf61f1662001-01-10 20:13:55 +00002121- The SocketServer module now sets the allow_reuse_address flag by
2122 default in the TCPServer class.
2123
2124- A new function, sys._getframe(), returns the stack frame pointer of
2125 the caller. This is intended only as a building block for
2126 higher-level mechanisms such as string interpolation.
2127
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002128- The pyexpat module supports a number of new handlers, which are
2129 available only in expat 1.2. If invocation of a callback fails, it
2130 will report an additional frame in the traceback. Parser objects
2131 participate now in garbage collection. If expat reports an unknown
2132 encoding, pyexpat will try to use a Python codec; that works only
2133 for single-byte charsets. The parser type objects is exposed as
2134 XMLParserObject.
2135
2136- xml.dom now offers standard definitions for symbolic node type and
2137 exception code constants, and a hierarchy of DOM exceptions. minidom
2138 was adjusted to use them.
2139
2140- The conformance of xml.dom.minidom to the DOM specification was
2141 improved. It detects a number of additional error cases; the
2142 previous/next relationship works even when the tree is modified;
2143 Node supports the normalize() method; NamedNodeMap, DocumentType and
2144 DOMImplementation classes were added; Element supports the
2145 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2146 method.
2147
Guido van Rossumf61f1662001-01-10 20:13:55 +00002148Build issues
2149
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002150- For Unix (and Unix-compatible) builds, configuration and building of
2151 extension modules is now greatly automated. Rather than having to
2152 edit the Modules/Setup file to indicate which modules should be
2153 built and where their include files and libraries are, a
2154 distutils-based setup.py script now takes care of building most
2155 extension modules. All extension modules built this way are built
2156 as shared libraries. Only a few modules that must be linked
2157 statically are still listed in the Setup file; you won't need to
2158 edit their configuration.
2159
2160- Python should now build out of the box on Cygwin. If it doesn't,
2161 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002162
2163- Python now always uses its own (renamed) implementation of getopt()
2164 -- there's too much variation among C library getopt()
2165 implementations.
2166
2167- C++ compilers are better supported; the CXX macro is always set to a
2168 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002169
Tim Petersd92dfe02000-12-12 01:18:41 +00002170Windows changes
2171
2172- select module: By default under Windows, a select() call
2173 can specify no more than 64 sockets. Python now boosts
2174 this Microsoft default to 512. If you need even more than
2175 that, see the MS docs (you'll need to #define FD_SETSIZE
2176 and recompile Python from source).
2177
Guido van Rossumf61f1662001-01-10 20:13:55 +00002178- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2179 subdirectory is no more!
2180
Tim Petersa3a3a032000-11-30 05:22:44 +00002181
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002182What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002183=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002184
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002185Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002186changes are in the file HISTORY. If you are making the jump directly
2187from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2188HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002189
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002190Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2191the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2192http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002193
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002194--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002195
2196======================================================================
2197
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002198What's new in 2.0 (since release candidate 1)?
2199==============================================
2200
2201Standard library
2202
2203- The copy_reg module was modified to clarify its intended use: to
2204 register pickle support for extension types, not for classes.
2205 pickle() will raise a TypeError if it is passed a class.
2206
2207- Fixed a bug in gettext's "normalize and expand" code that prevented
2208 it from finding an existing .mo file.
2209
2210- Restored support for HTTP/0.9 servers in httplib.
2211
Tim Peters989b7b92000-10-16 20:24:53 +00002212- The math module was changed to stop raising OverflowError in case of
2213 underflow, and return 0 instead in underflow cases. Whether Python
2214 used to raise OverflowError in case of underflow was platform-
2215 dependent (it did when the platform math library set errno to ERANGE
2216 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002217
2218- Fixed a bug in StringIO that occurred when the file position was not
2219 at the end of the file and write() was called with enough data to
2220 extend past the end of the file.
2221
2222- Fixed a bug that caused Tkinter error messages to get lost on
2223 Windows. The bug was fixed by replacing direct use of
2224 interp->result with Tcl_GetStringResult(interp).
2225
2226- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2227 redirect response.
2228
2229- Several changes were made to distutils: Some debugging code was
2230 removed from util. Fixed the installer used when an external zip
2231 program (like WinZip) is not found; the source code for this
2232 installer is in Misc/distutils. check_lib() was modified to behave
2233 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2234 test for whether installed modules are on sys.path was changed to
2235 use both normcase() and normpath().
2236
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002237- Several minor bugs were fixed in the xml package (the minidom,
2238 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002239
2240- The regression test driver (regrtest.py) behavior when invoked with
2241 -l changed: It now reports a count of objects that are recognized as
2242 garbage but not freed by the garbage collector.
2243
Tim Peters989b7b92000-10-16 20:24:53 +00002244- The regression test for the math module was changed to test
2245 exceptional behavior when the test is run in verbose mode. Python
2246 cannot yet guarantee consistent exception behavior across platforms,
2247 so the exception part of test_math is run only in verbose mode, and
2248 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002249
2250Internals
2251
2252- PyOS_CheckStack() has been disabled on Win64, where it caused
2253 test_sre to fail.
2254
2255Build issues
2256
2257- Changed compiler flags, so that gcc is always invoked with -Wall and
2258 -Wstrict-prototypes. Users compiling Python with GCC should see
2259 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002260 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002261 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002262
Tim Petersa3a3a032000-11-30 05:22:44 +00002263- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002264
2265Tools and other miscellany
2266
2267- The compiler in Tools/compiler was updated to support the new
2268 language features introduced in 2.0: extended print statement, list
2269 comprehensions, and augmented assignments. The new compiler should
2270 also be backwards compatible with Python 1.5.2; the compiler will
2271 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002272 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002273
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002274What's new in 2.0 release candidate 1 (since beta 2)?
2275=====================================================
2276
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002277What is release candidate 1?
2278
2279We believe that release candidate 1 will fix all known bugs that we
2280intend to fix for the 2.0 final release. This release should be a bit
2281more stable than the previous betas. We would like to see even more
2282widespread testing before the final release, so we are producing this
2283release candidate. The final release will be exactly the same unless
2284any show-stopping (or brown bag) bugs are found by testers of the
2285release candidate.
2286
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002287All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002288to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002289
2290Core language, builtins, and interpreter
2291
2292- A bug that caused crashes when __coerce__ was used with augmented
2293 assignment, e.g. +=, was fixed.
2294
2295- Raise ZeroDivisionError when raising zero to a negative number,
2296 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2297 power operator and the result of math.pow(0.0, -2.0) will vary by
2298 platform. On Linux, it raises a ValueError.
2299
2300- A bug in Unicode string interpolation was fixed that occasionally
2301 caused errors with formats including "%%". For example, the
2302 following expression "%% %s" % u"abc" no longer raises a TypeError.
2303
2304- Compilation of deeply nested expressions raises MemoryError instead
2305 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2306
2307- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2308 rendering them useless. They are now written in binary mode again.
2309
2310Standard library
2311
2312- Keyword arguments are now accepted for most pattern and match object
2313 methods in SRE, the standard regular expression engine.
2314
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002315- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002316 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002317
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002318- Several bugs in the Unicode handling and error handling in _tkinter
2319 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002320
2321- Fix memory management errors in Merge() and Tkapp_Call() routines.
2322
2323- Several changes were made to cStringIO to make it compatible with
2324 the file-like object interface and with StringIO. If operations are
2325 performed on a closed object, an exception is raised. The truncate
2326 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002327 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002328
2329- There were many changes made to the linuxaudiodev module and its
2330 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002331 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002332
2333 Note that this module is named poorly, because it should work
2334 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002335 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002336
2337 The module now raises exceptions when errors occur instead of
2338 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2339 audio) and defines a getptr() method that calls the
2340 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2341
2342- The library_version attribute, introduced in an earlier beta, was
2343 removed because it can not be supported with early versions of the C
2344 readline library, which provides no way to determine the version at
2345 compile-time.
2346
2347- The binascii module is now enabled on Win64.
2348
Tim Peters46446d62000-10-09 21:19:31 +00002349- tokenize.py no longer suffers "recursion depth" errors when parsing
2350 programs with very long string literals.
2351
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002352Internals
2353
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002354- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002355 which is called when the interpreter starts up to determine where
2356 the standard library is installed. These vulnerabilities affect all
2357 previous versions of Python and can be exploited by setting very
2358 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2359 setuid Python script, although use of the wrapper in
2360 Misc/setuid-prog.c will eliminate the vulnerability.
2361
2362- Fixed garbage collection bugs in instance creation that were
2363 triggered when errors occurred during initialization. The solution,
2364 applied in cPickle and in PyInstance_New(), is to call
2365 PyObject_GC_Init() after the initialization of the object's
2366 container attributes is complete.
2367
2368- pyexpat adds definitions of PyModule_AddStringConstant and
2369 PyModule_AddObject if the Python version is less than 2.0, which
2370 provides compatibility with PyXML on Python 1.5.2.
2371
2372- If the platform has a bogus definition for LONG_BIT (the number of
2373 bits in a long), an error will be reported at compile time.
2374
2375- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2376 collection crashes and possibly other, unreported crashes.
2377
2378- Fixed a memory leak in _PyUnicode_Fini().
2379
2380Build issues
2381
2382- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002383 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002384 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002385
2386- The mmap.PAGESIZE constant is now initialized using sysconf when
2387 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2388
2389- The md5 file should now compile on all platforms.
2390
2391- The select module now compiles on platforms that do not define
2392 POLLRDNORM and related constants.
2393
2394- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002395 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002396
Jeremy Hylton10921202000-10-09 18:34:12 +00002397- BeOS: A number of changes were made to the build and installation
2398 process. ar-fake now operates on a directory of object files.
2399 dl_export.h is gone, and its macros now appear on the mwcc command
2400 line during build on PPC BeOS.
2401
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002402- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002403 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002404
2405- Cygwin: Support for shared libraries, Tkinter, and sockets.
2406
2407- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2408
2409Tools and other miscellany
2410
2411- Removed debugging prints from main used with freeze.
2412
Tim Peters46446d62000-10-09 21:19:31 +00002413- IDLE auto-indent no longer crashes when it encounters Unicode
2414 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002415
2416What's new in 2.0 beta 2 (since beta 1)?
2417========================================
2418
2419Core language, builtins, and interpreter
2420
Tim Peters482c0212000-09-26 06:33:09 +00002421- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002422 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002423
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002424- Add -h and -V command line options to print the usage message and
2425 Python version number and exit immediately.
2426
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002427- eval() and exec accept Unicode objects as code parameters.
2428
2429- getattr() and setattr() now also accept Unicode objects for the
2430 attribute name, which are converted to strings using the default
2431 encoding before lookup.
2432
2433- Multiplication on string and Unicode now does proper bounds
2434 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2435 string is too long."
2436
2437- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002438 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002439
Jeremy Hylton1b618592000-09-26 05:32:36 +00002440
2441Standard library and extensions
2442
Guido van Rossum5b08f132001-04-16 02:05:23 +00002443- socket module: the OpenSSL code now adds support for RAND_status()
2444 and EGD (Entropy Gathering Device).
2445
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002446- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002447 argument checking; it still takes no arguments.
2448
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002449- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002450
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002451- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002452
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002453- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002454
2455- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002456 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002457
2458- copy: Copy Unicode objects atomically.
2459
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002460- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002461
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002462- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002463
Fred Drake67233bc2000-09-26 16:40:27 +00002464- dbm: Add get() and setdefault() methods to dbm object. Add constant
2465 `library' to module that names the library used. Added doc strings
2466 and method names to error messages. Uses configure to determine
2467 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2468 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002469
2470- distutils: Update to version 0.9.3.
2471
2472- dl: Add several dl.RTLD_ constants.
2473
2474- fpectl: Now supported on FreeBSD.
2475
2476- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2477 found by the collector will be saved in gc.garbage. This is useful
2478 for debugging a program that creates reference cycles.
2479
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002480- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002481 of HTTP class. Do not close socket on zero-length response. Do not
2482 crash when server sends invalid content-length header.
2483
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002484- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002485
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002486- marshal: When reading a short, sign-extend on platforms where shorts
2487 are bigger than 16 bits. When reading a long, repair the unportable
2488 sign extension that was being done for 64-bit machines. (It assumed
2489 that signed right shift sign-extends.)
2490
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002491- operator: Add contains(), invert(), __invert__() as aliases for
2492 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002493
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002494- os: Add support for popen2() and popen3() on all platforms where
2495 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002496
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002497- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002498 clicking on a file in Explorer (or passing the file name to the
2499 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002500
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002501- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002502 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002503
2504- pickle: Now raises ValueError when an invalid pickle that contains
2505 a non-string repr where a string repr was expected. This behavior
2506 matches cPickle.
2507
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002508- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002509
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002510- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002511
2512- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002513 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002514 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002515
2516- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002517 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002518
2519- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002520 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002521 few cycles during startup since the first call to
2522 setdefaultencoding() will initialize the codec registry and the
2523 encodings package.
2524
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002525- socket: Support for size hint in readlines() method of object returned
2526 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002527
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002528- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002529 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002530 is followed by whitespace.
2531
Tim Petersa3a3a032000-11-30 05:22:44 +00002532- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002533
2534- struct: Check ranges for bytes and shorts.
2535
2536- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002537 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002538
2539- Tkinter: Image objects are now guaranteed to have unique ids. Set
2540 event.delta to zero if Tk version doesn't support mousewheel.
2541 Removed some debugging prints.
2542
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002543- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002544
Fred Drake67233bc2000-09-26 16:40:27 +00002545- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002546 which works around a bug in Norton AntiVirus 2000 that leads directly
2547 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002548
2549- xml: New version detection code allows PyXML to override standard
2550 XML package if PyXML version is greater than 0.6.1.
2551
Fred Drake64bb3802000-09-26 16:21:35 +00002552- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2553 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2554 tree only for nodes which are sufficiently interesting to a specific
2555 application. Does not provide the HTML-specific extensions. Still
2556 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002557
Fred Drake64bb3802000-09-26 16:21:35 +00002558- xml.sax: SAX 2 support for Python, including all the handler
2559 interfaces needed to process XML 1.0 compliant XML. Some
2560 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002561
Fred Drake64bb3802000-09-26 16:21:35 +00002562- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2563 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002564
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002565
Jeremy Hylton1b618592000-09-26 05:32:36 +00002566C API
2567
2568- Add three new convenience functions for module initialization --
2569 PyModule_AddObject(), PyModule_AddIntConstant(), and
2570 PyModule_AddStringConstant().
2571
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002572- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002573 removed and add #error to Python.h if NULL isn't defined after
2574 #include of stdio.h.
2575
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002576- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002577 backwards compatibility (at the source level) with old extensions.
2578
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002579- A wrapper API was added for signal() and sigaction(). Instead of
2580 either function, always use PyOS_getsig() to get a signal handler
2581 and PyOS_setsig() to set one. A new convenience typedef
2582 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002583
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002584- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002585 internal data buffer and size of a string object -- or the default
2586 encoded version of a Unicode object.
2587
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002588- PyString_Size() and PyString_AsString() accept Unicode objects.
2589
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002590- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002591 exists). INT_MAX and LONG_MAX will always be defined, even if
2592 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002593
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002594- PyFloat_FromString takes a second argument, pend, that was
2595 effectively useless. It is now officially useless but preserved for
2596 backwards compatibility. If the pend argument is not NULL, *pend is
2597 set to NULL.
2598
2599- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2600 for the attribute name. See note on getattr() above.
2601
2602- A few bug fixes to argument processing for Unicode.
2603 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2604 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2605 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002606 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002607
2608- Py_BuildValue accepts B format (for bgen-generated code).
2609
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002610
Jeremy Hylton1b618592000-09-26 05:32:36 +00002611Internals
2612
2613- On Unix, fix code for finding Python installation directory so that
2614 it works when argv[0] is a relative path.
2615
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002616- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002617 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002618 rather than by generating a copy of the object.
2619
Tim Peters482c0212000-09-26 06:33:09 +00002620- Several of the internal Unicode tables are much smaller now, and
2621 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002622
Jeremy Hylton97693b02000-09-26 17:42:51 +00002623- In the garbage collector: Fixed bug in collection of tuples. Fixed
2624 bug that caused some instances to be removed from the container set
2625 while they were still live. Fixed parsing in gc.set_debug() for
2626 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002627
2628- Fixed refcount problem in instance deallocation that only occurred
2629 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2630
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002631- On Windows, getpythonregpath is now protected against null data in
2632 registry key.
2633
2634- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002635 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002636
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002637
Jeremy Hylton1b618592000-09-26 05:32:36 +00002638Build and platform-specific issues
2639
2640- Better support of GNU Pth via --with-pth configure option.
2641
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002642- Python/C API now properly exposed to dynamically-loaded extension
2643 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002644
2645- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2646 Don't define MS_SYNC to be zero when it is undefined. Added missing
2647 prototypes in posixmodule.c.
2648
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002649- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002650 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002651
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002652- Fix largefile support on older NetBSD systems and OpenBSD by adding
2653 define for TELL64.
2654
2655
2656Tools and other miscellany
2657
2658- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2659
2660- freeze: The modulefinder now works with 2.0 opcodes.
2661
Tim Petersa3a3a032000-11-30 05:22:44 +00002662- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002663 Move hackery of sys.argv until after the Tk instance has been
2664 created, which allows the application-specific Tkinter
2665 initialization to be executed if present; also pass an explicit
2666 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002667
Jeremy Hylton1b618592000-09-26 05:32:36 +00002668
2669What's new in 2.0 beta 1?
2670=========================
2671
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002672Source Incompatibilities
2673------------------------
2674
2675None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2676such as single-argument append(), connect() and bind(), and changes to
2677str(long) and repr(float).
2678
2679
2680Binary Incompatibilities
2681------------------------
2682
2683- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2684with Python 2.0; these extensions will have to be rebuilt for Python
26852.0.
2686
2687- On Windows, attempting to import a third party extension built for
2688Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2689can do about this. Check your PYTHONPATH environment variable!
2690
2691- Python bytecode files (*.pyc and *.pyo) are not compatible between
2692releases.
2693
2694
2695Overview of Changes Since 1.6
2696-----------------------------
2697
2698There are many new modules (including brand new XML support through
2699the xml package, and i18n support through the gettext module); a list
2700of all new modules is included below. Lots of bugs have been fixed.
2701
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002702The process for making major new changes to the language has changed
2703since Python 1.6. Enhancements must now be documented by a Python
2704Enhancement Proposal (PEP) before they can be accepted.
2705
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002706There are several important syntax enhancements, described in more
2707detail below:
2708
2709 - Augmented assignment, e.g. x += 1
2710
2711 - List comprehensions, e.g. [x**2 for x in range(10)]
2712
2713 - Extended import statement, e.g. import Module as Name
2714
2715 - Extended print statement, e.g. print >> file, "Hello"
2716
2717Other important changes:
2718
2719 - Optional collection of cyclical garbage
2720
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002721Python Enhancement Proposal (PEP)
2722---------------------------------
2723
2724PEP stands for Python Enhancement Proposal. A PEP is a design
2725document providing information to the Python community, or describing
2726a new feature for Python. The PEP should provide a concise technical
2727specification of the feature and a rationale for the feature.
2728
2729We intend PEPs to be the primary mechanisms for proposing new
2730features, for collecting community input on an issue, and for
2731documenting the design decisions that have gone into Python. The PEP
2732author is responsible for building consensus within the community and
2733documenting dissenting opinions.
2734
2735The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002736
2737Augmented Assignment
2738--------------------
2739
2740This must have been the most-requested feature of the past years!
2741Eleven new assignment operators were added:
2742
Guido van Rossume905e952000-09-05 12:42:46 +00002743 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002744
2745For example,
2746
2747 A += B
2748
2749is similar to
2750
2751 A = A + B
2752
2753except that A is evaluated only once (relevant when A is something
2754like dict[index].attr).
2755
2756However, if A is a mutable object, A may be modified in place. Thus,
2757if A is a number or a string, A += B has the same effect as A = A+B
2758(except A is only evaluated once); but if a is a list, A += B has the
2759same effect as A.extend(B)!
2760
2761Classes and built-in object types can override the new operators in
2762order to implement the in-place behavior; the not-in-place behavior is
2763used automatically as a fallback when an object doesn't implement the
2764in-place behavior. For classes, the method name is derived from the
2765method name for the corresponding not-in-place operator by inserting
2766an 'i' in front of the name, e.g. __iadd__ implements in-place
2767__add__.
2768
2769Augmented assignment was implemented by Thomas Wouters.
2770
2771
2772List Comprehensions
2773-------------------
2774
2775This is a flexible new notation for lists whose elements are computed
2776from another list (or lists). The simplest form is:
2777
2778 [<expression> for <variable> in <sequence>]
2779
Guido van Rossum56db0952000-09-06 23:34:25 +00002780For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002781This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002782
2783You can also add a condition:
2784
2785 [<expression> for <variable> in <sequence> if <condition>]
2786
2787For example, [w for w in words if w == w.lower()] would yield the list
2788of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002789than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002790
2791You can also have nested for loops and more than one 'if' clause. For
2792example, here's a function that flattens a sequence of sequences::
2793
2794 def flatten(seq):
2795 return [x for subseq in seq for x in subseq]
2796
2797 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2798
2799This prints
2800
2801 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2802
2803List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002804Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002805
2806
2807Extended Import Statement
2808-------------------------
2809
2810Many people have asked for a way to import a module under a different
2811name. This can be accomplished like this:
2812
2813 import foo
2814 bar = foo
2815 del foo
2816
2817but this common idiom gets old quickly. A simple extension of the
2818import statement now allows this to be written as follows:
2819
2820 import foo as bar
2821
2822There's also a variant for 'from ... import':
2823
2824 from foo import bar as spam
2825
2826This also works with packages; e.g. you can write this:
2827
2828 import test.regrtest as regrtest
2829
2830Note that 'as' is not a new keyword -- it is recognized only in this
2831context (this is only possible because the syntax for the import
2832statement doesn't involve expressions).
2833
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002834Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002835
2836
2837Extended Print Statement
2838------------------------
2839
2840Easily the most controversial new feature, this extension to the print
2841statement adds an option to make the output go to a different file
2842than the default sys.stdout.
2843
2844For example, to write an error message to sys.stderr, you can now
2845write:
2846
2847 print >> sys.stderr, "Error: bad dog!"
2848
2849As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002850evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002851
2852 print >> None, "Hello world"
2853
2854is equivalent to
2855
2856 print "Hello world"
2857
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002858Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002859
2860
2861Optional Collection of Cyclical Garbage
2862---------------------------------------
2863
2864Python is now equipped with a garbage collector that can hunt down
2865cyclical references between Python objects. It's no replacement for
2866reference counting; in fact, it depends on the reference counts being
2867correct, and decides that a set of objects belong to a cycle if all
2868their reference counts can be accounted for from their references to
2869each other. This devious scheme was first proposed by Eric Tiedemann,
2870and brought to implementation by Neil Schemenauer.
2871
2872There's a module "gc" that lets you control some parameters of the
2873garbage collection. There's also an option to the configure script
2874that lets you enable or disable the garbage collection. In 2.0b1,
2875it's on by default, so that we (hopefully) can collect decent user
2876experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002877performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002878off by default in the final 2.0 release.
2879
2880
2881Smaller Changes
2882---------------
2883
2884A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2885map(None, seq1, seq2, ...) when the sequences have the same length;
2886i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2887the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002888zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002889
2890sys.version_info is a tuple (major, minor, micro, level, serial).
2891
2892Dictionaries have an odd new method, setdefault(key, default).
2893dict.setdefault(key, default) returns dict[key] if it exists; if not,
2894it sets dict[key] to default and returns that value. Thus:
2895
2896 dict.setdefault(key, []).append(item)
2897
2898does the same work as this common idiom:
2899
2900 if not dict.has_key(key):
2901 dict[key] = []
2902 dict[key].append(item)
2903
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002904There are two new variants of SyntaxError that are raised for
2905indentation-related errors: IndentationError and TabError.
2906
2907Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2908escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002909
2910The limits on the size of expressions and file in Python source code
2911have been raised from 2**16 to 2**32. Previous versions of Python
2912were limited because the maximum argument size the Python VM accepted
2913was 2**16. This limited the size of object constructor expressions,
2914e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2915limit was raised thanks to a patch by Charles Waldman that effectively
2916fixes the problem. It is now much more likely that you will be
2917limited by available memory than by an arbitrary limit in Python.
2918
2919The interpreter's maximum recursion depth can be modified by Python
2920programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2921limit is the maximum number of recursive calls that can be made by
2922Python code. The limit exists to prevent infinite recursion from
2923overflowing the C stack and causing a core dump. The default value is
29241000. The maximum safe value for a particular platform can be found
2925by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002926
2927New Modules and Packages
2928------------------------
2929
2930atexit - for registering functions to be called when Python exits.
2931
2932imputil - Greg Stein's alternative API for writing custom import
2933hooks.
2934
2935pyexpat - an interface to the Expat XML parser, contributed by Paul
2936Prescod.
2937
2938xml - a new package with XML support code organized (so far) in three
2939subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2940would fill a volume. There's a special feature whereby a
2941user-installed package named _xmlplus overrides the standard
2942xmlpackage; this is intended to give the XML SIG a hook to distribute
2943backwards-compatible updates to the standard xml package.
2944
2945webbrowser - a platform-independent API to launch a web browser.
2946
2947
Guido van Rossume905e952000-09-05 12:42:46 +00002948Changed Modules
2949---------------
2950
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002951array -- new methods for array objects: count, extend, index, pop, and
2952remove
2953
2954binascii -- new functions b2a_hex and a2b_hex that convert between
2955binary data and its hex representation
2956
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002957calendar -- Many new functions that support features including control
2958over which day of the week is the first day, returning strings instead
2959of printing them. Also new symbolic constants for days of week,
2960e.g. MONDAY, ..., SUNDAY.
2961
2962cgi -- FieldStorage objects have a getvalue method that works like a
2963dictionary's get method and returns the value attribute of the object.
2964
2965ConfigParser -- The parser object has new methods has_option,
2966remove_section, remove_option, set, and write. They allow the module
2967to be used for writing config files as well as reading them.
2968
2969ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002970optionally support the RFC 959 REST command.
2971
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002972gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002973
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002974httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2975the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002976
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002977locale -- implement getdefaultlocale for Win32 and Macintosh
2978
2979marshal -- no longer dumps core when marshaling deeply nested or
2980recursive data structures
2981
2982os -- new functions isatty, seteuid, setegid, setreuid, setregid
2983
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002984os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2985support under Unix.
2986
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002987os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002988
2989os.path -- fix semantics of os.path.commonprefix
2990
2991smtplib -- support for sending very long messages
2992
2993socket -- new function getfqdn()
2994
2995readline -- new functions to read, write and truncate history files.
2996The readline section of the library reference manual contains an
2997example.
2998
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002999select -- add interface to poll system call
3000
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003001shutil -- new copyfileobj function
3002
3003SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3004HTTP server.
3005
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003006Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003007
3008urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003009e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003010
3011whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003012
3013
3014Obsolete Modules
3015----------------
3016
3017None. However note that 1.6 made a whole slew of modules obsolete:
3018stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3019poly, zmod, strop, util, whatsound.
3020
3021
3022Changed, New, Obsolete Tools
3023----------------------------
3024
Tim Peters8b092332000-09-05 20:15:25 +00003025None.
Guido van Rossume905e952000-09-05 12:42:46 +00003026
3027
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003028C-level Changes
3029---------------
3030
3031Several cleanup jobs were carried out throughout the source code.
3032
3033All C code was converted to ANSI C; we got rid of all uses of the
3034Py_PROTO() macro, which makes the header files a lot more readable.
3035
3036Most of the portability hacks were moved to a new header file,
3037pyport.h; several other new header files were added and some old
3038header files were removed, in an attempt to create a more rational set
3039of header files. (Few of these ever need to be included explicitly;
3040they are all included by Python.h.)
3041
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003042Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003043and Win64, especially for the new Intel Itanium processor. Mick also
3044added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003045
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003046The C APIs to return an object's size have been update to consistently
3047use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3048previous versions, the abstract interfaces used PyXXX_Length and the
3049concrete interfaces used PyXXX_Size. The old names,
3050e.g. PyObject_Length, are still available for backwards compatibility
3051at the API level, but are deprecated.
3052
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003053The PyOS_CheckStack function has been implemented on Windows by
3054Fredrik Lundh. It prevents Python from failing with a stack overflow
3055on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003056
3057The GC changes resulted in creation of two new slots on object,
3058tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003059the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003060
3061The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003062C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003063
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003064PyErr_Format has been updated to automatically calculate the size of
3065the buffer needed to hold the formatted result string. This change
3066prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003067
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003068New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003069
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003070PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3071that are the same as their non-Ex counterparts except they take an
3072extra flag argument that tells them to close the file when done.
3073
3074XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003075
Tim Peters8b092332000-09-05 20:15:25 +00003076
3077Windows Changes
3078---------------
3079
3080New popen2/popen3/peopen4 in os module (see Changed Modules above).
3081
3082os.popen is much more usable on Windows 95 and 98. See Microsoft
3083Knowledge Base article Q150956. The Win9x workaround described there
3084is implemented by the new w9xpopen.exe helper in the root of your
3085Python installation. Note that Python uses this internally; it is not
3086a standalone program.
3087
3088Administrator privileges are no longer required to install Python
3089on Windows NT or Windows 2000. If you have administrator privileges,
3090Python's registry info will be written under HKEY_LOCAL_MACHINE.
3091Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003092under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003093uses of Python, but will prevent some advanced uses from working
3094(for example, running a Python script as an NT service, or possibly
3095from CGI).
3096
3097[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3098installer; instead, it installs the needed Tcl/Tk files directly in the
3099Python directory. If you already have a Tcl/Tk installation, this
3100wastes some disk space (about 4 Megs) but avoids problems with
3101conflicting Tcl/Tk installations, and makes it much easier for Python
3102to ensure that Tcl/Tk can find all its files.
3103
3104[This was new in 1.6] The Windows installer now installs by default in
3105\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3106
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003107
3108Updates to the changes between 1.5.2 and 1.6
3109--------------------------------------------
3110
3111The 1.6 NEWS file can't be changed after the release is done, so here
3112is some late-breaking news:
3113
3114New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3115and changes to getlocale() and setlocale().
3116
3117The new module is now enabled per default.
3118
3119It is not true that the encodings codecs cannot be used for normal
3120strings: the string.encode() (which is also present on 8-bit strings
3121!) allows using them for 8-bit strings too, e.g. to convert files from
3122cp1252 (Windows) to latin-1 or vice-versa.
3123
3124Japanese codecs are available from Tamito KAJIYAMA:
3125http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3126
3127
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003128======================================================================