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Tim Petersb3c9af12001-11-17 00:21:57 +00001What's New in Python 2.2c1?
2XXX Release date: ??-Dec-2001 XXX
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 Peters84362bc2001-10-19 17:55:30 +000028What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000029Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000030===========================
31
32Type/class unification and new-style classes
33
Guido van Rossum3d27df02001-11-15 20:27:54 +000034- Multiple inheritance mixing new-style and classic classes in the
35 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000036
37 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000038 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000039
40 The MRO (method resolution order) for each base class is respected
41 according to its kind, but the MRO for the derived class is computed
42 using new-style MRO rules if any base clase is a new-style class.
43 This needs to be documented.
44
Tim Petersa427a2b2001-10-29 22:25:45 +000045- The new builtin dictionary() constructor, and dictionary type, have
46 been renamed to dict. This reflects a decade of common usage.
47
Guido van Rossum3fc08d22001-11-15 20:33:10 +000048- dict() now accepts an iterable object producing 2-sequences. For
49 example, dict(d.items()) == d for any dictionary d. The argument,
50 and the elements of the argument, can be any iterable objects.
51
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000052- New-style classes can now have a __del__ method, which is called
53 when the instance is deleted (just like for classic classes).
54
Guido van Rossum12d955c2001-10-26 14:56:06 +000055- Assignment to object.__dict__ is now possible, for objects that are
56 instances of new-style classes that have a __dict__ (unless the base
57 class forbids it).
58
Guido van Rossumc8e56452001-10-22 00:43:43 +000059- Methods of built-in types now properly check for keyword arguments
60 (formerly these were silently ignored). The only built-in methods
61 that take keyword arguments are __call__, __init__ and __new__.
62
Guido van Rossum86443212001-10-27 22:28:54 +000063- The socket function has been converted to a type; see below.
64
Tim Peters84362bc2001-10-19 17:55:30 +000065Core and builtins
66
Jeremy Hylton249aaed2001-11-09 21:06:24 +000067- Assignment to __debug__ raises SyntaxError at compile-time. This
68 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +000069 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +000070
Guido van Rossum12d955c2001-10-26 14:56:06 +000071- Clarified the error messages for unsupported operands to an operator
72 (like 1 + '').
73
Tim Peters84362bc2001-10-19 17:55:30 +000074Extension modules
75
Tim Peters5ebfd362001-11-13 23:11:19 +000076- mmap has a new keyword argument, "access", allowing a uniform way for
77 both Windows and Unix users to create read-only, write-through and
78 copy-on-write memory mappings. This was previously possible only on
79 Unix. A new keyword argument was required to support this in a
80 uniform way because the mmap() signuatures had diverged across
81 platforms. Thanks to Jay T Miller for repairing this!
82
Tim Peters169ded02001-11-03 19:57:21 +000083- By default, the gc.garbage list now contains only those instances in
84 unreachable cycles that have __del__ methods; in 2.1 it contained all
85 instances in unreachable cycles. "Instances" here has been generalized
86 to include instances of both new-style and old-style classes.
87
Guido van Rossum12d955c2001-10-26 14:56:06 +000088- The socket module defines a new method for socket objects,
89 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000090 send() until all data has been sent. Also, the socket function has
91 been converted to a subclassable type, like list and tuple (etc.)
92 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000093
94- Various bugfixes to the curses module. There is now a test suite
95 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +000096
Guido van Rossum692adf12001-10-30 03:03:03 +000097- binascii.b2a_base64 no longer places an arbitrary restriction of 57
98 bytes on its input.
99
Tim Peters84362bc2001-10-19 17:55:30 +0000100Library
101
Tim Peters5ebfd362001-11-13 23:11:19 +0000102- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000103 convenience function.
104
Tim Peters75335872001-11-03 19:35:43 +0000105- Symbolic group names in regular expressions must be unique. For
106 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
107 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000108 Python 2.2 detects this error at regexp compilation time;
109 previously, the error went undetected, and results were
110 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
111 pattern.subn() methods have been rewritten in C. Also, an
112 experimental function/method finditer() has been added, which works
113 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000114
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000115- Tix exposes more commands through the classes DirSelectBox,
116 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
117 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
118 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
119
Tim Peters98791af2001-10-23 01:59:54 +0000120- Traceback objects are now scanned by cyclic garbage collection, so
121 cycles created by casual use of sys.exc_info() no longer cause
122 permanent memory leaks (provided garbage collection is enabled).
123
Guido van Rossum49192142001-10-24 20:51:44 +0000124- os.extsep -- a new variable needed by the RISCOS support. It is the
125 separator used by extensions, and is '.' on all platforms except
126 RISCOS, where it is '/'. There is no need to use this variable
127 unless you have a masochistic desire to port your code to RISCOS.
128
Barry Warsaw012852b2001-11-16 16:17:27 +0000129- mimetypes.py has optional support for non-standard, but commonly
130 found types. guess_type() and guess_extension() now accept an
131 optional `strict' flag, defaulting to true, which controls whether
132 recognize non-standard types or not. A few non-standard types we
133 know about have been added. Also, when run as a script, there are
134 new -l and -e options.
135
136- statcache is now deprecated.
137
138- email.Utils.formatdate() now produces the preferred RFC 2822 style
139 dates with numeric timezones (it used to produce obsolete dates
140 hard coded to "GMT" timezone). An optional `localtime' flag is
141 added to produce dates in the local timezone, with daylight savings
142 time properly taken into account.
143
144- In pickle and cPickle, instead of masking errors in load() by
145 transforming them into SystemError, we let the original exception
146 propagate out. Also, implement support for __safe_for_unpickling__
147 in pickle, as it already was supported in cPickle.
148
Tim Peters84362bc2001-10-19 17:55:30 +0000149Tools/Demos
150
151Build
152
Barry Warsaw012852b2001-11-16 16:17:27 +0000153- The dbm module is built using libdb1 if available. The bsddb module
154 is built with libdb3 if available.
155
156- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
157
Tim Peters84362bc2001-10-19 17:55:30 +0000158C API
159
Tim Peters1fc240e2001-10-26 05:06:50 +0000160- New function PySequence_Fast_GET_SIZE() returns the size of a non-
161 NULL result from PySequence_Fast(), more quickly than calling
162 PySequence_Size().
163
Barry Warsaw012852b2001-11-16 16:17:27 +0000164- New argument unpacking function PyArg_UnpackTuple() added.
165
166- New functions PyObject_CallFunctionObjArgs() and
167 PyObject_CallMethodObjArgs() have been added to make it more
168 convenient and efficient to call functions and methods from C.
169
170- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
171 possible that this will propagate errors it didn't before.
172
173- New function PyObject_CheckReadBuffer(), which returns true if its
174 argument supports the single-segment readable buffer interface.
175
Tim Peters84362bc2001-10-19 17:55:30 +0000176New platforms
177
Guido van Rossum86443212001-10-27 22:28:54 +0000178- We've finally confirmed that this release builds on HP-UX 11.00,
179 *with* threads, and passes the test suite.
180
Tim Peters7a33d8b2001-11-05 02:51:07 +0000181- Thanks to a series of patches from Michael Muller, Python may build
182 again under OS/2 Visual Age C++.
183
Guido van Rossum49192142001-10-24 20:51:44 +0000184- Updated RISCOS port by Dietmar Schwertberger.
185
Tim Peters84362bc2001-10-19 17:55:30 +0000186Tests
187
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000188- Added a test script for the curses module. It isn't run automatically;
189 regrtest.py must be run with '-u curses' to enable it.
190
Tim Peters84362bc2001-10-19 17:55:30 +0000191Windows
192
Barry Warsaw012852b2001-11-16 16:17:27 +0000193Mac
194
195- PythonScript has been moved to unsupported and is slated to be
196 removed completely in the next release.
197
198- It should now be possible to build applets that work on both OS9 and
199 OSX.
200
201- The core is now linked with CoreServices not Carbon; as a side
202 result, default 8bit encoding on OSX is now ASCII.
203
204- Python should now build on OSX 10.1.1
205
Tim Peters84362bc2001-10-19 17:55:30 +0000206
Tim Petersabf925f2001-09-28 21:53:42 +0000207What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000208Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000209===========================
210
211Type/class unification and new-style classes
212
Guido van Rossum687ae002001-10-15 22:03:32 +0000213- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000214 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000215 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000216 remains: the __dict__ of a new-style class is a read-only proxy; you
217 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000218 __defined__ attribute of new-style types no longer exists, for lack
219 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000220 future a __cache__ may be resurrected with a similar function, if I
221 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000222
Tim Peters1c9ca872001-10-04 06:43:12 +0000223- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
224 always returned None, even when there was a class docstring).
225
226- doctest now finds and runs docstrings attached to new-style classes,
227 class methods, static methods, and properties.
228
Guido van Rossum9074ef62001-10-16 21:34:49 +0000229Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000230
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000231- A very subtle syntactical pitfall in list comprehensions was fixed.
232 For example: [a+b for a in 'abc', for b in 'def']. The comma in
233 this example is a mistake. Previously, this would silently let 'a'
234 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
235 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
236 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
237 Note that [a for a in <singleton>] is a convoluted way to say
238 [<singleton>] anyway, so it's not like any expressiveness is lost.
239
Guido van Rossum9074ef62001-10-16 21:34:49 +0000240- getattr(obj, name, default) now only catches AttributeError, as
241 documented, rather than returning the default value for all
242 exceptions (which could mask bugs in a __getattr__ hook, for
243 example).
244
Fred Drakecb7a6b52001-10-22 18:41:51 +0000245- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000246 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000247 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000248 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000249
Guido van Rossum1c486092001-10-19 02:05:35 +0000250- unicode(obj) now behaves more like str(obj), accepting arbitrary
251 objects, and calling a __unicode__ method if it exists.
252 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000253 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000254
Barry Warsawf6fb1712001-10-19 05:35:40 +0000255- isinstance() now allows any object as the first argument and a
256 class, a type or something with a __bases__ tuple attribute for the
257 second argument. The second argument may also be a tuple of a
258 class, type, or something with __bases__, in which case isinstance()
259 will return true if the first argument is an instance of any of the
260 things contained in the second argument tuple. E.g.
261
262 isinstance(x, (A, B))
263
264 returns true if x is an instance of A or B.
265
Guido van Rossum9074ef62001-10-16 21:34:49 +0000266Extension modules
267
268- thread.start_new_thread() now returns the thread ID (previously None).
269
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000270- binascii has now two quopri support functions, a2b_qp and b2a_qp.
271
Guido van Rossumc524d952001-10-19 01:31:59 +0000272- readline now supports setting the startup_hook and the
273 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000274
Guido van Rossumc524d952001-10-19 01:31:59 +0000275- os and posix supports chroot(), setgroups() and unsetenv() where
276 available. The stat(), fstat(), statvfs() and fstatvfs() functions
277 now return "pseudo-sequences" -- the various fields can now be
278 accessed as attributes (e.g. os.stat("/").st_mtime) but for
279 backwards compatibility they also behave as a fixed-length sequence.
280 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000281 attributes.
282
283- time: localtime(), gmtime() and strptime() now return a
284 pseudo-sequence similar to the os.stat() return value, with
285 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000286
Guido van Rossum9074ef62001-10-16 21:34:49 +0000287- Decompression objects in the zlib module now accept an optional
288 second parameter to decompress() that specifies the maximum amount
289 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000290
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000291- optional SSL support in the socket module now exports OpenSSL
292 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
293 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000294 automatically seed its PRNG. Also, the keyfile and certfile
295 arguments to socket.ssl() are now optional.
296
297- posixmodule (and by extension, the os module on POSIX platforms) now
298 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000299
Guido van Rossum9074ef62001-10-16 21:34:49 +0000300Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000301
Tim Peters7402f792001-10-02 03:53:41 +0000302- doctest now excludes functions and classes not defined by the module
303 being tested, thanks to Tim Hochberg.
304
Fred Drakecb7a6b52001-10-22 18:41:51 +0000305- HotShot, a new profiler implemented using a C-based callback, has
306 been added. This substantially reduces the overhead of profiling,
307 but it is still quite preliminary. Support modules and
308 documentation will be added in upcoming releases (before 2.2 final).
309
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000310- profile now produces correct output in situations where an exception
311 raised in Python is cleared by C code (e.g. hasattr()). This used
312 to cause wrong output, including spurious claims of recursive
313 functions and attribution of time spent to the wrong function.
314
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000315 The code and documentation for the derived OldProfile and HotProfile
316 profiling classes was removed. The code hasn't worked for years (if
317 you tried to use them, they raised exceptions). OldProfile
318 intended to reproduce the behavior of the profiler Python used more
319 than 7 years ago, and isn't interesting anymore. HotProfile intended
320 to provide a faster profiler (but producing less information), and
321 that's a worthy goal we intend to meet via a different approach (but
322 without losing information).
323
Tim Peterscce092d2001-10-09 05:31:56 +0000324- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000325 a much better system-specific calibration constant. The constant can
326 now be specified in an instance constructor, or as a Profile class or
327 instance variable, instead of by editing profile.py's source code.
328 Calibration must still be done manually (see the docs for the profile
329 module).
330
331 Note that Profile.calibrate() must be overriden by subclasses.
332 Improving the accuracy required exploiting detailed knowledge of
333 profiler internals; the earlier method abstracted away the details
334 and measured a simplified model instead, but consequently computed
335 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000336
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000337- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000338 which indicates whether output is intended for the header 'Q'
339 encoding.
340
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000341- The SocketServer.ThreadingMixIn class now closes the request after
342 finish_request() returns. (Not when it errors out though.)
343
Barry Warsawf6fb1712001-10-19 05:35:40 +0000344- The nntplib module's NNTP.body() method has grown a `file' argument
345 to allow saving the message body to a file.
346
347- The email package has added a class email.Parser.HeaderParser which
348 only parses headers and does not recurse into the message's body.
349 Also, the module/class MIMEAudio has been added for representing
350 audio data (contributed by Anthony Baxter).
351
352- ftplib should be able to handle files > 2GB.
353
354- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
355 ON, and OFF.
356
Fred Drakecb7a6b52001-10-22 18:41:51 +0000357- xml.dom.minidom NodeList objects now support the length attribute
358 and item() method as required by the DOM specifications.
359
Guido van Rossumed554f62001-10-02 23:15:37 +0000360Tools/Demos
361
362- Demo/dns was removed. It no longer serves any purpose; a package
363 derived from it is now maintained by Anthony Baxter, see
364 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000365
Barry Warsawf6fb1712001-10-19 05:35:40 +0000366- The freeze tool has been made more robust, and two new options have
367 been added: -X and -E.
368
Tim Petersabf925f2001-09-28 21:53:42 +0000369Build
370
Barry Warsawf6fb1712001-10-19 05:35:40 +0000371- configure will use CXX in LINKCC if CXX is used to build main() and
372 the system requires to link a C++ main using the C++ compiler.
373
Tim Petersabf925f2001-09-28 21:53:42 +0000374C API
375
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000376- The documentation for the tp_compare slot is updated to require that
377 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
378 not correct. This is not yet enforced but will be enforced in
379 Python 2.3; even later, we may use -2 to indicate errors and +2 for
380 "NotImplemented". Right now, -1 should be used for an error return.
381
Tim Petersd38b1c72001-09-30 05:09:37 +0000382- PyLong_AsLongLong() now accepts int (as well as long) arguments.
383 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
384 as long) arguments.
385
Guido van Rossum3c288632001-10-16 21:13:49 +0000386- PyThread_start_new_thread() now returns a long int giving the thread
387 ID, if one can be calculated; it returns -1 for error, 0 if no
388 thread ID is calculated (this is an incompatible change, but only
389 the thread module used this API). This code has only really been
390 tested on Linux and Windows; other platforms please beware (and
391 report any bugs or strange behavior).
392
Guido van Rossum1c486092001-10-19 02:05:35 +0000393- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
394 input.
395
Tim Petersabf925f2001-09-28 21:53:42 +0000396New platforms
397
398Tests
399
400Windows
401
Tim Peters04cf1d32001-10-09 22:39:40 +0000402- Installer: If you install IDLE, and don't disable file-extension
403 registration, a new "Edit with IDLE" context (right-click) menu entry
404 is created for .py and .pyw files.
405
Tim Peters1ce3cf72001-10-01 17:58:40 +0000406- The signal module now supports SIGBREAK on Windows, thanks to Steven
407 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
408 action remains to call Win32 ExitProcess(). This can be changed via
409 signal.signal(). For example:
410
411 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
412 # (SIGINT) behavior.
413 import signal
414 signal.signal(signal.SIGBREAK,
415 signal.default_int_handler)
416
417 try:
418 while 1:
419 pass
420 except KeyboardInterrupt:
421 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
422 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
423 # program without the possibility for any Python-level cleanup).
424 print "Clean exit"
425
Tim Petersabf925f2001-09-28 21:53:42 +0000426
Tim Petersb07352e2001-09-08 01:25:47 +0000427What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000428Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000429===========================
430
Guido van Rossum808eea72001-09-25 04:15:41 +0000431Type/class unification and new-style classes
432
433- pydoc and inspect are now aware of new-style classes;
434 e.g. help(list) at the interactive prompt now shows proper
435 documentation for all operations on list objects.
436
437- Applications using Jim Fulton's ExtensionClass module can now safely
438 be used with Python 2.2. In particular, Zope 2.4.1 now works with
439 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
440 examples also work again. It is hoped that Gtk and Boost also work
441 with 2.2a4 and beyond. (If you can confirm this, please write
442 webmaster@python.org; if there are still problems, please open a bug
443 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000444
Tim Peters66c1a522001-09-24 21:17:50 +0000445- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
446 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
447 in the constructed property object. fget, fset and fdel weren't
448 discoverable from Python in 2.2a3. __doc__ is new, and allows to
449 associate a docstring with a property.
450
Guido van Rossum808eea72001-09-25 04:15:41 +0000451- Comparison overloading is now more completely implemented. For
452 example, a str subclass instance can properly be compared to a str
453 instance, and it can properly overload comparison. Ditto for most
454 other built-in object types.
455
456- The repr() of new-style classes has changed; instead of <type
457 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
458 *except* for built-in types, which are still rendered as <type
459 'Foo'> (to avoid upsetting existing code that might parse or
460 otherwise rely on repr() of certain type objects).
461
462- The repr() of new-style objects is now always <Foo object at XXX>;
463 previously, it was sometimes <Foo instance at XXX>.
464
465- For new-style classes, what was previously called __getattr__ is now
466 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000467 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000468 one in classic classes is defined which is called only if regular
469 attribute access raises AttributeError; to catch *all* attribute
470 access, you can use __getattribute__ (for new-style classes). If
471 both are defined, __getattribute__ is called first, and if it raises
472 AttributeError, __getattr__ is called.
473
474- The __class__ attribute of new-style objects can be assigned to.
475 The new class must have the same C-level object layout as the old
476 class.
477
478- The builtin file type can be subclassed now. In the usual pattern,
479 "file" is the name of the builtin type, and file() is a new builtin
480 constructor, with the same signature as the builtin open() function.
481 file() is now the preferred way to open a file.
482
483- Previously, __new__ would only see sequential arguments passed to
484 the type in a constructor call; __init__ would see both sequential
485 and keyword arguments. This made no sense whatsoever any more, so
486 now both __new__ and __init__ see all arguments.
487
488- Previously, hash() applied to an instance of a subclass of str or
489 unicode always returned 0. This has been repaired.
490
491- Previously, an operation on an instance of a subclass of an
492 immutable type (int, long, float, complex, tuple, str, unicode),
493 where the subtype didn't override the operation (and so the
494 operation was handled by the builtin type), could return that
495 instance instead a value of the base type. For example, if s was of
496 a str sublass type, s[:] returned s as-is. Now it returns a str
497 with the same value as s.
498
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000499- Provisional support for pickling new-style objects has been added.
500
Guido van Rossum808eea72001-09-25 04:15:41 +0000501Core
502
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000503- file.writelines() now accepts any iterable object producing strings.
504
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000505- PyUnicode_FromEncodedObject() now works very much like
506 PyObject_Str(obj) in that it tries to use __str__/tp_str
507 on the object if the object is not a string or buffer. This
508 makes unicode() behave like str() when applied to non-string/buffer
509 objects.
510
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000511- PyFile_WriteObject now passes Unicode objects to the file's write
512 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000513 of a print statement must support Unicode objects, i.e. they must
514 at least convert them into ASCII strings.
515
Guido van Rossum624c8af2001-09-18 15:21:04 +0000516- Thread scheduling on Solaris should be improved; it is no longer
517 necessary to insert a small sleep at the start of a thread in order
518 to let other runnable threads be scheduled.
519
Tim Petersb07352e2001-09-08 01:25:47 +0000520Library
521
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000522- StringIO.StringIO instances and cStringIO.StringIO instances support
523 read character buffer compatible objects for their .write() methods.
524 These objects are converted to strings and then handled as such
525 by the instances.
526
Barry Warsaw2f600732001-09-24 04:28:10 +0000527- The "email" package has been added. This is basically a port of the
528 mimelib package <http://sf.net/projects/mimelib> with API changes
529 and some implementations updated to use iterators and generators.
530
Tim Peters8a9c2842001-09-22 21:30:22 +0000531- difflib.ndiff() and difflib.Differ.compare() are generators now. This
532 restores the ability of Tools/scripts/ndiff.py to start producing output
533 before the entire comparison is complete.
534
Barry Warsaw58b072d2001-09-22 04:44:21 +0000535- StringIO.StringIO instances and cStringIO.StringIO instances support
536 iteration just like file objects (i.e. their .readline() method is
537 called for each iteration until it returns an empty string).
538
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000539- The codecs module has grown four new helper APIs to access
540 builtin codecs: getencoder(), getdecoder(), getreader(),
541 getwriter().
542
Guido van Rossum624c8af2001-09-18 15:21:04 +0000543- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
544 simplifies writing XML RPC servers.
545
Barry Warsaw647d5e82001-09-28 17:01:02 +0000546- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000547 after interpretation of symbolic links. On non-Unix systems, this
548 is an alias for os.path.abspath().
549
Tim Peters16a77ad2001-09-08 04:00:12 +0000550- operator.indexOf() (PySequence_Index() in the C API) now works with any
551 iterable object.
552
Guido van Rossum624c8af2001-09-18 15:21:04 +0000553- smtplib now supports various authentication and security features of
554 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000555
Guido van Rossum624c8af2001-09-18 15:21:04 +0000556- hmac: a new module implementing keyed hashing for message
557 authentication.
558
559- mimetypes now recognizes more extensions and file types. At the
560 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000561
Guido van Rossum624c8af2001-09-18 15:21:04 +0000562- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000563 Python 2.2 bytecode generation. It has also been promoted from a
564 Tool to a standard library package. (Tools/compiler still exists as
565 a sample driver.)
566
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000567Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000568
Tim Petersb07352e2001-09-08 01:25:47 +0000569Build
570
Guido van Rossum624c8af2001-09-18 15:21:04 +0000571- Large file support (LFS) is now automatic when the platform supports
572 it; no more manual configuration tweaks are needed. On Linux, at
573 least, it's possible to have a system whose C library supports large
574 files but whose kernel doesn't; in this case, large file support is
575 still enabled but doesn't do you any good unless you upgrade your
576 kernel or share your Python executable with another system whose
577 kernel has large file support.
578
579- The configure script now supplies plausible defaults in a
580 cross-compilation environment. This doesn't mean that the supplied
581 values are always correct, or that cross-compilation now works
582 flawlessly -- but it's a first step (and it shuts up most of
583 autoconf's warnings about AC_TRY_RUN).
584
585- The Unix build is now a bit less chatty, courtesy of the parser
586 generator. The build is completely silent (except for errors) when
587 using "make -s", thanks to a -q option to setup.py.
588
Tim Petersb07352e2001-09-08 01:25:47 +0000589C API
590
Guido van Rossum624c8af2001-09-18 15:21:04 +0000591- The "structmember" API now supports some new flag bits to deny read
592 and/or write access to attributes in restricted execution mode.
593
Tim Petersb07352e2001-09-08 01:25:47 +0000594New platforms
595
Guido van Rossum624c8af2001-09-18 15:21:04 +0000596- Compaq's iPAQ handheld, running the "familiar" Linux distribution
597 (http://familiar.handhelds.org).
598
Tim Petersb07352e2001-09-08 01:25:47 +0000599Tests
600
Tim Peters8a9c2842001-09-22 21:30:22 +0000601- The "classic" standard tests, which work by comparing stdout to
602 an expected-output file under Lib/test/output/, no longer stop at
603 the first mismatch. Instead the test is run to completion, and a
604 variant of ndiff-style comparison is used to report all differences.
605 This is much easier to understand than the previous style of reporting.
606
607- The unittest-based standard tests now use regrtest's test_main()
608 convention, instead of running as a side-effect of merely being
609 imported. This allows these tests to be run in more natural and
610 flexible ways as unittests, outside the regrtest framework.
611
612- regrtest.py is much better integrated with unittest and doctest now,
613 especially in regard to reporting errors.
614
Tim Petersb07352e2001-09-08 01:25:47 +0000615Windows
616
Guido van Rossum624c8af2001-09-18 15:21:04 +0000617- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000618 that support it (NTFS under Windows 2000). See "What's New in
619 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000620
Tim Petersb07352e2001-09-08 01:25:47 +0000621
Tim Petersedc99312001-08-22 21:36:50 +0000622What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000623Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000624===========================
625
626Core
627
Tim Peters9fffa3e2001-09-04 05:14:19 +0000628- Conversion of long to float now raises OverflowError if the long is too
629 big to represent as a C double.
630
Tim Peters32f453e2001-09-03 08:35:41 +0000631- The 3-argument builtin pow() no longer allows a third non-None argument
632 if either of the first two arguments is a float, or if both are of
633 integer types and the second argument is negative (in which latter case
634 the arguments are converted to float, so this is really the same
635 restriction).
636
Tim Peters5d2b77c2001-09-03 05:47:38 +0000637- The builtin dir() now returns more information, and sometimes much
638 more, generally naming all attributes of an object, and all attributes
639 reachable from the object via its class, and from its class's base
640 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
641 an empty list. In 2.2a3,
642
643 >>> dir([])
644 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
645 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
646 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
647 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
648 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
649 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
650 'reverse', 'sort']
651
652 dir(module) continues to return only the module's attributes, though.
653
Tim Petersbdee63f2001-09-02 03:40:59 +0000654- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000655 than raising OverflowError. This is a partial implementation of PEP
656 237. You can use -Wdefault::OverflowWarning to enable a warning for
657 this situation, and -Werror::OverflowWarning to revert to the old
658 OverflowError exception.
659
Guido van Rossum61c345f2001-09-04 03:26:15 +0000660- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000661 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000662 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
663 -Qold, meaning the / operator has its classic meaning and no
664 warnings are issued. Using -Qwarn issues a run-time warning about
665 all uses of classic division for int and long arguments; -Qwarnall
666 also warns about classic division for float and complex arguments
667 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
668 new division by default, but only in the __main__ module. You can
669 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
670 __main__ module new division, and warns about classic division
671 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000672
Tim Petersbdee63f2001-09-02 03:40:59 +0000673- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000674 long, float, str, unicode, and tuple. (The types complex, list and
675 dictionary can also be subclassed; this was introduced earlier.)
676 Note that restrictions apply when subclassing immutable built-in
677 types: you can only affect the value of the instance by overloading
678 __new__. You can add mutable attributes, and the subclass instances
679 will have a __dict__ attribute, but you cannot change the "value"
680 (as implemented by the base class) of an immutable subclass instance
681 once it is created.
682
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000683- The dictionary constructor now takes an optional argument, a
684 mapping-like object, and initializes the dictionary from its
685 (key, value) pairs.
686
Tim Petersbdee63f2001-09-02 03:40:59 +0000687- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000688 "cooperative super calls" in a multiple inheritance setting. For an
689 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
690
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000691- A new built-in type, property, has been added. This enables the
692 creation of "properties". These are attributes implemented by
693 getter and setter functions (or only one of these for read-only or
694 write-only attributes), without the need to override __getattr__.
695 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000696
Tim Petersbdee63f2001-09-02 03:40:59 +0000697- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000698 liberalized, to allow leading zeroes. Examples of literals now
699 legal that were SyntaxErrors before:
700
701 00.0 0e3 0100j 07.5 00000000000000000008.
702
Tim Petersbdee63f2001-09-02 03:40:59 +0000703- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000704 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
705
Tim Petersedc99312001-08-22 21:36:50 +0000706Library
707
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000708- telnetlib includes symbolic names for the options, and support for
709 setting an option negotiation callback.
710
Tim Petersa40c7932001-09-05 22:36:56 +0000711- The new C standard no longer requires that math libraries set errno to
712 ERANGE on overflow. For platform libraries that exploit this new
713 freedom, Python's overflow-checking was wholly broken. A new overflow-
714 checking scheme attempts to repair that, but may not be reliable on all
715 platforms (C doesn't seem to provide anything both useful and portable
716 in this area anymore).
717
Martin v. Löwis44f86962001-09-05 13:44:54 +0000718- Asynchronous timeout actions are available through the new class
719 threading.Timer.
720
Tim Peters78526162001-09-05 00:53:45 +0000721- math.log and math.log10 now return sensible results for even huge
722 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
723
Tim Petersbdee63f2001-09-02 03:40:59 +0000724- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000725 currently held. See the docs for the imp module.
726
Tim Petersbdee63f2001-09-02 03:40:59 +0000727- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000728 dumps containing ints written on platforms where Python ints are 8 bytes.
729 When read on a box where Python ints are 4 bytes, such values are
730 converted to Python longs.
731
Tim Petersbdee63f2001-09-02 03:40:59 +0000732- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000733 code objects is no longer allowed. This plugs a security hole.
734
Steve Purcell6091cd62001-09-06 16:05:17 +0000735- unittest.TestResult instances no longer store references to tracebacks
736 generated by test failures. This prevents unexpected dangling references
737 to objects that should be garbage collected between tests.
738
Tim Petersedc99312001-08-22 21:36:50 +0000739Tools
740
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000741- Tools/scripts/fixdiv.py has been added which can be used to fix
742 division operators as per PEP 238.
743
Tim Petersedc99312001-08-22 21:36:50 +0000744Build
745
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000746- If you are an adventurous person using Mac OS X you may want to look at
747 Mac/OSX. There is a Makefile there that will build Python as a real Mac
748 application, which can be used for experimenting with Carbon or Cocoa.
749 Discussion of this on pythonmac-sig, please.
750
Tim Peters7eea37e2001-09-04 22:08:56 +0000751C API
752
753- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000754
Tim Peters9fffa3e2001-09-04 05:14:19 +0000755- Note that PyLong_AsDouble can fail! This has always been true, but no
756 callers checked for it. It's more likely to fail now, because overflow
757 errors are properly detected now. The proper way to check:
758
759 double x = PyLong_AsDouble(some_long_object);
760 if (x == -1.0 && PyErr_Occurred()) {
761 /* The conversion failed. */
762 }
763
Tim Petersbdee63f2001-09-02 03:40:59 +0000764- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000765 compile but will not participate in GC. To upgrade an extension
766 module:
767
768 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000769
Neil Schemenauer4042c692001-08-30 15:38:01 +0000770 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
771 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000772
Neil Schemenauer4042c692001-08-30 15:38:01 +0000773 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
774 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000775
Neil Schemenauer4042c692001-08-30 15:38:01 +0000776 - remove PyGC_HEAD_SIZE from object size calculations
777
778 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
779
Tim Petersbdee63f2001-09-02 03:40:59 +0000780- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000781 These can be used safely to construct string objects from a
782 sprintf-style format string (similar to the format string supported
783 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000784
Tim Petersedc99312001-08-22 21:36:50 +0000785New platforms
786
Tim Petersb7da0902001-09-02 23:01:43 +0000787- Stephen Hansen contributed patches sufficient to get a clean compile
788 under Borland C (Windows), but he reports problems running it and ran
789 out of time to complete the port. Volunteers? Expect a MemoryError
790 when importing the types module; this is probably shallow, and
791 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000792
Tim Petersedc99312001-08-22 21:36:50 +0000793Tests
794
795Windows
796
Tim Peters6e13a562001-09-06 00:32:15 +0000797- Large file support is now enabled on Win32 platforms as well as on
798 Win64. This means that, for example, you can use f.tell() and f.seek()
799 to manipulate files larger than 2 gigabytes (provided you have enough
800 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000801 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
802 filesize limit, and large file support makes no difference there.
803 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
804 NTFS has no practical limit on file size, and files of any size can be
805 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000806
Tim Petersbdee63f2001-09-02 03:40:59 +0000807- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000808 points to command.com (patch from Brian Quinlan).
809
Tim Petersedc99312001-08-22 21:36:50 +0000810
Tim Peters20f51a72001-07-21 02:31:40 +0000811What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000812Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000813===========================
814
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000815Build
816
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000817- Tim Peters developed a brand new Windows installer using Wise 8.1,
818 generously donated to us by Wise Solutions.
819
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000820- configure supports a new option --enable-unicode, with the values
821 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
822 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000823
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000824- A new configure option --enable-framework builds a Mac OS X framework,
825 which "make frameworkinstall" will install. This provides a starting
826 point for more mac-like functionality, join pythonmac-sig@python.org
827 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000828
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000829- The NeXT platform is no longer supported.
830
831- The `new' module is now statically linked.
832
Tim Peters0afb6092001-08-15 06:06:44 +0000833Tools
834
835- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000836 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000837 the module docstring for details.
838
Tim Peters20f51a72001-07-21 02:31:40 +0000839Tests
840
Tim Peters5e824c32001-08-12 22:25:01 +0000841- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000842 platforms, allowing to give clearer test result output. regrtest
843 also has optional --use/-u switch to run normally disabled tests
844 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000845
Tim Peters20f51a72001-07-21 02:31:40 +0000846- Several new tests in the standard test suite, with special thanks to
847 Nick Mathewson.
848
849Core
850
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000851- The floor division operator // has been added as outlined in PEP
852 238. The / operator still provides classic division (and will until
853 Python 3.0) unless "from __future__ import division" is included, in
854 which case the / operator will provide true division. The operator
855 module provides truediv() and floordiv() functions. Augmented
856 assignment variants are included, as are the equivalent overloadable
857 methods and C API methods. See the PEP for a full discussion:
858 <http://python.sf.net/peps/pep-0238.html>
859
Tim Peters6cd6a822001-08-17 22:11:27 +0000860- Future statements are now effective in simulated interactive shells
861 (like IDLE). This should "just work" by magic, but read Michael
862 Hudson's "Future statements in simulated shells" PEP 264 for full
863 details: <http://python.sf.net/peps/pep-0264.html>.
864
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000865- The type/class unification (PEP 252-253) was integrated into the
866 trunk and is not so tentative any more (the exact specification of
867 some features is still tentative). A lot of work has done on fixing
868 bugs and adding robustness and features (performance still has to
869 come a long way).
870
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000871- Warnings about a mismatch in the Python API during extension import
872 now use the Python warning framework (which makes it possible to
873 write filters for these warnings).
874
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000875- A function's __dict__ (aka func_dict) will now always be a
876 dictionary. It used to be possible to delete it or set it to None,
877 but now both actions raise TypeErrors. It is still legal to set it
878 to a dictionary object. Getting func.__dict__ before any attributes
879 have been assigned now returns an empty dictionary instead of None.
880
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000881- A new command line option, -E, was added which disables the use of
882 all environment variables, or at least those that are specifically
883 significant to Python. Usually those have a name starting with
884 "PYTHON". This was used to fix a problem where the tests fail if
885 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
886 older distribution.
887
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000888Library
889
Tim Peters5e824c32001-08-12 22:25:01 +0000890- New class Differ and new functions ndiff() and restore() in difflib.py.
891 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000892 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000893
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000894- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
895 value using the minimal quoting required for the value; more
896 reliable than using xml.sax.saxutils.escape() for attribute values.
897
898- Readline completion support for cmd.Cmd was added.
899
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000900- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
901
902- Added function threading.BoundedSemaphore()
903
904- Added Ka-Ping Yee's cgitb.py module.
905
906- The `new' module now exposes the CO_xxx flags.
907
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000908New platforms
909
910C API
911
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000912- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
913 which provide a cross-platform implementations for the
914 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
915 the standard sprintf() and vsprintf() C lib APIs, these versions
916 apply bounds checking on the used buffer which enhances protection
917 against buffer overruns.
918
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000919- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000920 and extensions using different Unicode widths is rendered next to
921 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000922 will result in an ImportError. Unicode extensions writers must make
923 sure to check the Unicode width compatibility in their extensions by
924 using at least one of the mangled Unicode APIs in the extension.
925
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000926- Two new flags METH_NOARGS and METH_O are available in method definition
927 tables to simplify implementation of methods with no arguments and a
928 single untyped argument. Calling such methods is more efficient than
929 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
930 deprecated.
931
Tim Petersc1731372001-08-04 08:12:36 +0000932Windows
933
934- "import module" now compiles module.pyw if it exists and nothing else
935 relevant is found.
936
Tim Peters20f51a72001-07-21 02:31:40 +0000937
Guido van Rossum55a78992001-07-17 17:22:32 +0000938What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000939Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000940===========================
941
942Core
Tim Petersa814db52001-05-14 07:05:58 +0000943
Tim Peters6d6c1a32001-08-02 04:15:00 +0000944- TENTATIVELY, a large amount of code implementing much of what's
945 described in PEP 252 (Making Types Look More Like Classes) and PEP
946 253 (Subtyping Built-in Types) was added. This will be released
947 with Python 2.2a1. Documentation will be provided separately
948 through http://www.python.org/2.2/. The purpose of releasing this
949 with Python 2.2a1 is to test backwards compatibility. It is
950 possible, though not likely, that a decision is made not to release
951 this code as part of 2.2 final, if any serious backwards
952 incompapatibilities are found during alpha testing that cannot be
953 repaired.
954
Guido van Rossum55a78992001-07-17 17:22:32 +0000955- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000956 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000957 more 'yield' statements. See PEP 255. Since this adds a new
958 keyword to the language, this feature must be enabled by including a
959 future statement: "from __future__ import generators" (see PEP 236).
960 Generators will become a standard feature in a future release
961 (probably 2.3). Without this future statement, 'yield' remains an
962 ordinary identifier, but a warning is issued each time it is used.
963 (These warnings currently don't conform to the warnings framework of
964 PEP 230; we intend to fix this in 2.2a2.)
965
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000966- The UTF-16 codec was modified to be more RFC compliant. It will now
967 only remove BOM characters at the start of the string and then
968 only if running in native mode (UTF-16-LE and -BE won't remove a
969 leading BMO character).
970
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000971- Strings now have a new method .decode() to complement the already
972 existing .encode() method. These two methods provide direct access
973 to the corresponding decoders and encoders of the registered codecs.
974
975 To enhance the usability of the .encode() method, the special
976 casing of Unicode object return values was dropped (Unicode objects
977 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000978
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000979 Both methods will now return whatever the codec in charge of the
980 requested encoding returns as object, e.g. Unicode codecs will
981 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
982 will return u"äöü"). This enables codec writer to create codecs
983 for various simple to use conversions.
984
985 New codecs were added to demonstrate these new features (the .encode()
986 and .decode() columns indicate the type of the returned objects):
987
988 Name | .encode() | .decode() | Description
989 ----------------------------------------------------------------------
990 uu | string | string | UU codec (e.g. for email)
991 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000992 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000993 zlib | string | string | zlib compression
994 hex | string | string | 2-byte hex codec
995 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
996
Mark Hammond2a0af792001-05-14 03:09:36 +0000997- Some operating systems now support the concept of a default Unicode
998 encoding for file system operations. Notably, Windows supports 'mbcs'
999 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001000 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001001 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001002
1003 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001004 functions that return filenames (such as os.listdir()) to return Python
1005 string objects pre-encoded using the default file system encoding for
1006 the platform. As this encoding is likely to be different from Python's
1007 default encoding, converting this name to a Unicode object before passing
1008 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001009 would attempt to use its default encoding (generally ASCII) rather than
1010 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001011
Tim Petersa814db52001-05-14 07:05:58 +00001012 In general, this change simply removes surprises when working with
1013 Unicode and the file system, making these operations work as you expect,
1014 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001015 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001016
Tim Peters61dff2b2001-05-08 15:43:37 +00001017- Float (and complex) literals in source code were evaluated to full
1018 precision only when running from a .py file; the same code loaded from a
1019 .pyc (or .pyo) file could suffer numeric differences starting at about the
1020 12th significant decimal digit. For example, on a machine with IEEE-754
1021 floating arithmetic,
1022
1023 x = 9007199254740992.0
1024 print long(x)
1025
1026 printed 9007199254740992 if run directly from .py, but 9007199254740000
1027 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1028 str(float) instead of repr(float) when building code objects. marshal
1029 now uses repr(float) instead, which should reproduce floats to full
1030 machine precision (assuming the platform C float<->string I/O conversion
1031 functions are of good quality).
1032
1033 This may cause floating-point results to change in some cases, and
1034 usually for the better, but may also cause numerically unstable
1035 algorithms to break.
1036
Tim Peters2f228e72001-05-13 00:19:31 +00001037- The implementation of dicts suffers fewer collisions, which has speed
1038 benefits. However, the order in which dict entries appear in dict.keys(),
1039 dict.values() and dict.items() may differ from previous releases for a
1040 given dict. Nothing is defined about this order, so no program should
1041 rely on it. Nevertheless, it's easy to write test cases that rely on the
1042 order by accident, typically because of printing the str() or repr() of a
1043 dict to an "expected results" file. See Lib/test/test_support.py's new
1044 sortdict(dict) function for a simple way to display a dict in sorted
1045 order.
1046
Tim Peters7a3bfc32001-06-12 01:22:22 +00001047- Many other small changes to dicts were made, resulting in faster
1048 operation along the most common code paths.
1049
Guido van Rossum10315822001-05-01 20:54:30 +00001050- Dictionary objects now support the "in" operator: "x in dict" means
1051 the same as dict.has_key(x).
1052
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001053- The update() method of dictionaries now accepts generic mapping
1054 objects. Specifically the argument object must support the .keys()
1055 and __getitem__() methods. This allows you to say, for example,
1056 {}.update(UserDict())
1057
Guido van Rossum10315822001-05-01 20:54:30 +00001058- Iterators were added; this is a generalized way of providing values
1059 to a for loop. See PEP 234. There's a new built-in function iter()
1060 to return an iterator. There's a new protocol to get the next value
1061 from an iterator using the next() method (in Python) or the
1062 tp_iternext slot (in C). There's a new protocol to get iterators
1063 using the __iter__() method (in Python) or the tp_iter slot (in C).
1064 Iterating (i.e. a for loop) over a dictionary generates its keys.
1065 Iterating over a file generates its lines.
1066
Tim Petersf553f892001-05-01 20:45:31 +00001067- The following functions were generalized to work nicely with iterator
1068 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001069 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001070 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1071 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001072 join() method of strings
1073 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001074 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1075 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001076 right-hand side of assignment statements with multiple targets, such as
1077 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001078
Tim Petersd85e1022001-05-11 21:51:48 +00001079- Accessing module attributes is significantly faster (for example,
1080 random.random or os.path or yourPythonModule.yourAttribute).
1081
Tim Peterse63415e2001-05-08 04:38:29 +00001082- Comparing dictionary objects via == and != is faster, and now works even
1083 if the keys and values don't support comparisons other than ==.
1084
Tim Peters95bf9392001-05-10 08:32:44 +00001085- Comparing dictionaries in ways other than == and != is slower: there were
1086 insecurities in the dict comparison implementation that could cause Python
1087 to crash if the element comparison routines for the dict keys and/or
1088 values mutated the dicts. Making the code bulletproof slowed it down.
1089
Tim Peterseb28ef22001-06-02 05:27:19 +00001090- Collisions in dicts are resolved via a new approach, which can help
1091 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001092 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001093 faster now. Thanks to Christian Tismer for pointing out the cause and
1094 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001095
Tim Peters52e155e2001-06-16 05:42:57 +00001096- repr() is much faster for large containers (dict, list, tuple).
1097
1098
Tim Petersa814db52001-05-14 07:05:58 +00001099Library
1100
Fred Drake960fdf92001-07-20 18:38:26 +00001101- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1102 were added to the string module. These a locale-indenpendent
1103 constants, unlike letters, lowercase, and uppercase. These are now
1104 use in appropriate locations in the standard library.
1105
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001106- The flags used in dlopen calls can now be configured using
1107 sys.setdlopenflags and queried using sys.getdlopenflags.
1108
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001109- Fredrik Lundh's xmlrpclib is now a standard library module. This
1110 provides full client-side XML-RPC support. In addition,
1111 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1112 one asyncore-based). Thanks to Eric Raymond for the documentation.
1113
Guido van Rossum643d3912001-07-05 14:46:25 +00001114- The xrange() object is simplified: it no longer supports slicing,
1115 repetition, comparisons, efficient 'in' checking, the tolist()
1116 method, or the start, stop and step attributes. See PEP 260.
1117
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001118- A new function fnmatch.filter to filter lists of file names was added.
1119
Barry Warsawffd674d2001-05-22 16:00:10 +00001120- calendar.py uses month and day names based on the current locale.
1121
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001122- strop is now *really* obsolete (this was announced before with 1.6),
1123 and issues DeprecationWarning when used (except for the four items
1124 that are still imported into string.py).
1125
Tim Petersa814db52001-05-14 07:05:58 +00001126- Cookie.py now sorts key+value pairs by key in output strings.
1127
1128- pprint.isrecursive(object) didn't correctly identify recursive objects.
1129 Now it does.
1130
Tim Peters95b3f782001-05-14 18:39:41 +00001131- pprint functions now much faster for large containers (tuple, list, dict).
1132
Tim Peters7b9542a2001-06-10 23:40:19 +00001133- New 'q' and 'Q' format codes in the struct module, corresponding to C
1134 types "long long" and "unsigned long long" (on Windows, __int64). In
1135 native mode, these can be used only when the platform C compiler supports
1136 these types (when HAVE_LONG_LONG is #define'd by the Python config
1137 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001138 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1139 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001140
Guido van Rossum83213cc2001-06-12 16:48:52 +00001141- The site module installs a new built-in function 'help' that invokes
1142 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1143 it displays a message reminding the user to use 'help()' or
1144 'help(object)'.
1145
Tim Petersa814db52001-05-14 07:05:58 +00001146Tests
1147
1148- New test_mutants.py runs dict comparisons where the key and value
1149 comparison operators mutute the dicts randomly during comparison. This
1150 rapidly causes Python to crash under earlier releases (not for the faint
1151 of heart: it can also cause Win9x to freeze or reboot!).
1152
1153- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001154 pprint.isreadable() return sensible results. Also verifies that simple
1155 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001156
Tim Peters4324aa32001-05-28 22:30:08 +00001157C API
1158
1159- Removed the unused last_is_sticky argument from the internal
1160 _PyTuple_Resize(). If this affects you, you were cheating.
1161
1162
Guido van Rossum55a78992001-07-17 17:22:32 +00001163======================================================================
1164
1165
Guido van Rossumffe13be2001-04-16 18:46:45 +00001166What's New in Python 2.1 (final)?
1167=================================
1168
1169We only changed a few things since the last release candidate, all in
1170Python library code:
1171
1172- A bug in the locale module was fixed that affected locales which
1173 define no grouping for numeric formatting.
1174
1175- A few bugs in the weakref module's implementations of weak
1176 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1177 and the test suite was updated to check for these bugs.
1178
1179- An old bug in the os.path.walk() function (introduced in Python
1180 2.0!) was fixed: a non-existent file would cause an exception
1181 instead of being ignored.
1182
1183- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1184 PyChecker.
1185
1186
Guido van Rossum5b08f132001-04-16 02:05:23 +00001187What's New in Python 2.1c2?
1188===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001189
Guido van Rossum5b08f132001-04-16 02:05:23 +00001190A flurry of small changes, and one showstopper fixed in the nick of
1191time made it necessary to release another release candidate. The list
1192here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001193
Guido van Rossum5b08f132001-04-16 02:05:23 +00001194Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001195
Guido van Rossum5b08f132001-04-16 02:05:23 +00001196- Tim discovered a nasty bug in the dictionary code, caused by
1197 PyDict_Next() calling dict_resize(), and the GC code's use of
1198 PyDict_Next() violating an assumption in dict_items(). This was
1199 fixed with considerable amounts of band-aid, but the net effect is a
1200 saner and more robust implementation.
1201
1202- Made a bunch of symbols static that were accidentally global.
1203
1204Build and Ports
1205
1206- The setup.py script didn't check for a new enough version of zlib
1207 (1.1.3 is needed). Now it does.
1208
1209- Changed "make clean" target to also remove shared libraries.
1210
1211- Added a more general warning about the SGI Irix optimizer to README.
1212
1213Library
1214
1215- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1216 omitted the slash between host and file.html.
1217
1218- The mailbox module's _Mailbox class contained a completely broken
1219 and undocumented seek() method. Ripped it out.
1220
1221- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1222 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1223
1224- Fixed a few last-minute bugs in unittest.
1225
1226Extensions
1227
1228- Reverted the patch to the OpenSSL code in socketmodule.c to support
1229 RAND_status() and the EGD, and the subsequent patch that tried to
1230 fix it for pre-0.9.5 versions; the problem with the patch is that on
1231 some systems it issues a warning whenever socket is imported, and
1232 that's unacceptable.
1233
1234Tests
1235
1236- Fixed the pickle tests to work with "import test.test_pickle".
1237
1238- Tweaked test_locale.py to actually run the test Windows.
1239
1240- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1241 not "wb" (which is not a valid mode at all).
1242
1243- Fix pstats browser crashes. Import readline if it exists to make
1244 the user interface nicer.
1245
1246- Add "import thread" to the top of test modules that import the
1247 threading module (test_asynchat and test_threadedtempfile). This
1248 prevents test failures caused by a broken threading module resulting
1249 from a previously caught failed import.
1250
1251- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1252 needed on some platforms (e.g. Solaris 8) when the tests are run
1253 twice in succession.
1254
1255- Skip rather than fail test_sunaudiodev if no audio device is found.
1256
1257
1258What's New in Python 2.1c1?
1259===========================
1260
1261This list was significantly updated when 2.1c2 was released; the 2.1c1
1262release didn't mention most changes that were actually part of 2.1c1:
1263
1264Legal
1265
1266- Copyright was assigned to the Python Software Foundation (PSF) and a
1267 PSF license (very similar to the CNRI license) was added.
1268
1269- The CNRI copyright notice was updated to include 2001.
1270
1271Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001272
Guido van Rossumc9932722001-04-12 02:31:27 +00001273- After a public outcry, assignment to __debug__ is no longer illegal;
1274 instead, a warning is issued. It will become illegal in 2.2.
1275
Guido van Rossum5b08f132001-04-16 02:05:23 +00001276- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1277 "%#x" now always prepends "0x", even if the value is zero.
1278
1279- Fixed some nits in the bytecode compiler.
1280
1281- Fixed core dumps when calling certain kinds of non-functions.
1282
1283- Fixed various core dumps caused by reference count bugs.
1284
1285Build and Ports
1286
1287- Use INSTALL_SCRIPT to install script files.
1288
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001289- New port: SCO Unixware 7, by Billy G. Allie.
1290
Guido van Rossum5b08f132001-04-16 02:05:23 +00001291- Updated RISCOS port.
1292
1293- Updated BeOS port and notes.
1294
1295- Various other porting problems resolved.
1296
1297Library
1298
1299- The TERMIOS and SOCKET modules are now truly obsolete and
1300 unnecessary. Their symbols are incorporated in the termios and
1301 socket modules.
1302
1303- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1304 better tests for pickling.
1305
1306- threading: make Condition.wait() robust against KeyboardInterrupt.
1307
1308- zipfile: add support to zipfile to support opening an archive
1309 represented by an open file rather than a file name. Fix bug where
1310 the archive was not properly closed. Fixed a bug in this bugfix
1311 where flush() was called for a read-only file.
1312
1313- imputil: added an uninstall() method to the ImportManager.
1314
1315- Canvas: fixed bugs in lower() and tkraise() methods.
1316
1317- SocketServer: API change (added overridable close_request() method)
1318 so that the TCP server can explicitly close the request.
1319
1320- pstats: Eric Raymond added a simple interactive statistics browser,
1321 invoked when the module is run as a script.
1322
1323- locale: fixed a problem in format().
1324
1325- webbrowser: made it work when the BROWSER environment variable has a
1326 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1327 KDE 2. Fixed some other nits.
1328
1329- unittest: changes to allow using a different exception than
1330 AssertionError, and added a few more function aliases. Some other
1331 small changes.
1332
1333- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1334
1335- asynchat: fixed a critical bug in asynchat that slipped through the
1336 2.1b2 release. Fixed another rare bug.
1337
1338- Fix some unqualified except: clauses (always a bad code example).
1339
1340XML
1341
1342- pyexpat: new API get_version_string().
1343
1344- Fixed some minidom bugs.
1345
1346Extensions
1347
1348- Fixed a core dump in _weakref. Removed the weakref.mapping()
1349 function (it adds nothing to the API).
1350
1351- Rationalized the use of header files in the readline module, to make
1352 it compile (albeit with some warnings) with the very recent readline
1353 4.2, without breaking for earlier versions.
1354
1355- Hopefully fixed a buffering problem in linuxaudiodev.
1356
1357- Attempted a fix to make the OpenSSL support in the socket module
1358 work again with pre-0.9.5 versions of OpenSSL.
1359
1360Tests
1361
1362- Added a test case for asynchat and asyncore.
1363
1364- Removed coupling between tests where one test failing could break
1365 another.
1366
1367Tools
1368
1369- Ping added an interactive help browser to pydoc, fixed some nits
1370 in the rest of the pydoc code, and added some features to his
1371 inspect module.
1372
1373- An updated python-mode.el version 4.1 which integrates Ken
1374 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1375 much nicer in XEmacs and Emacs. When stepping through your program
1376 with pdb, in either the shell window or the *Python* window, the
1377 source file and line will be tracked by an arrow. Very cool!
1378
1379- IDLE: syntax warnings in interactive mode are changed into errors.
1380
1381- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001382 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001383
1384- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001385
Barry Warsaw11e89c72001-04-11 20:37:57 +00001386
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001387What's New in Python 2.1 beta 2?
1388================================
1389
Guido van Rossum053ae352001-03-22 14:17:21 +00001390(Unlisted are many fixed bugs, more documentation, etc.)
1391
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001392Core language, builtins, and interpreter
1393
Guido van Rossum053ae352001-03-22 14:17:21 +00001394- The nested scopes work (enabled by "from __future__ import
1395 nested_scopes") is completed; in particular, the future now extends
1396 into code executed through exec, eval() and execfile(), and into the
1397 interactive interpreter.
1398
1399- When calling a base class method (e.g. BaseClass.__init__(self)),
1400 this is now allowed even if self is not strictly spoken a class
1401 instance (e.g. when using metaclasses or the Don Beaudry hook).
1402
1403- Slice objects are now comparable but not hashable; this prevents
1404 dict[:] from being accepted but meaningless.
1405
1406- Complex division is now calculated using less braindead algorithms.
1407 This doesn't change semantics except it's more likely to give useful
1408 results in extreme cases. Complex repr() now uses full precision
1409 like float repr().
1410
1411- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1412
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001413- It is illegal to assign to the name __debug__, which is set when the
1414 interpreter starts. It is effectively a compile-time constant.
1415
1416- A warning will be issued if a global statement for a variable
1417 follows a use or assignment of that variable.
1418
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001419Standard library
1420
Guido van Rossum053ae352001-03-22 14:17:21 +00001421- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1422 inspired by JUnit), is now part of the standard library. You now
1423 have a choice of two testing frameworks: unittest requires you to
1424 write testcases as separate code, doctest gathers them from
1425 docstrings. Both approaches have their advantages and
1426 disadvantages.
1427
1428- A new module Tix was added, which wraps the Tix extension library
1429 for Tk. With that module, it is not necessary to statically link
1430 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1431 require" command. See Demo/tix/.
1432
1433- tzparse.py is now obsolete.
1434
1435- In gzip.py, the seek() and tell() methods are removed -- they were
1436 non-functional anyway, and it's better if callers can test for their
1437 existence with hasattr().
1438
1439Python/C API
1440
1441- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1442 that's already in the dictionary during a PyDict_Next() iteration.
1443 This used to fail occasionally when a dictionary resize operation
1444 could be triggered that would rehash all the keys. All other
1445 modifications to the dictionary are still off-limits during a
1446 PyDict_Next() iteration!
1447
1448- New extended APIs related to passing compiler variables around.
1449
1450- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1451 implement isinstance() and issubclass().
1452
1453- Py_BuildValue() now has a "D" conversion to create a Python complex
1454 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001455
Fred Drake4e262a92001-03-22 18:26:47 +00001456- Extensions types which support weak references must now set the
1457 field allocated for the weak reference machinery to NULL themselves;
1458 this is done to avoid the cost of checking each object for having a
1459 weakly referencable type in PyObject_INIT(), since most types are
1460 not weakly referencable.
1461
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001462- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1463 free variables and cell variables to and from the frame's f_locals.
1464
1465- Variants of several functions defined in pythonrun.h have been added
1466 to support the nested_scopes future statement. The variants all end
1467 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1468 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1469 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001470 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001471
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001472Distutils
1473
1474- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1475 into the release tree.
1476
Tim Peters0e57abf2001-05-02 07:39:38 +00001477- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001478 (an uninstaller, more customization of the installer's display)
1479
1480- from Jack Jansen: added Mac-specific code to generate a dialog for
1481 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001482 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001483 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001484
1485- added 'platforms' and 'keywords' to the set of metadata that can be
1486 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001487
1488- applied patches from Jason Tishler to make the compiler class work with
1489 Cygwin.
1490
1491
Tim Peters2fe289a2001-03-01 22:19:38 +00001492What's New in Python 2.1 beta 1?
1493================================
Tim Petersd66595f2001-02-04 03:09:53 +00001494
1495Core language, builtins, and interpreter
1496
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001497- Following an outcry from the community about the amount of code
1498 broken by the nested scopes feature introduced in 2.1a2, we decided
1499 to make this feature optional, and to wait until Python 2.2 (or at
1500 least 6 months) to make it standard. The option can be enabled on a
1501 per-module basis by adding "from __future__ import nested_scopes" at
1502 the beginning of a module (before any other statements, but after
1503 comments and an optional docstring). See PEP 236 (Back to the
1504 __future__) for a description of the __future__ statement. PEP 227
1505 (Statically Nested Scopes) has been updated to reflect this change,
1506 and to clarify the semantics in a number of endcases.
1507
1508- The nested scopes code, when enabled, has been hardened, and most
1509 bugs and memory leaks in it have been fixed.
1510
1511- Compile-time warnings are now generated for a number of conditions
1512 that will break or change in meaning when nested scopes are enabled:
1513
1514 - Using "from...import *" or "exec" without in-clause in a function
1515 scope that also defines a lambda or nested function with one or
1516 more free (non-local) variables. The presence of the import* or
1517 bare exec makes it impossible for the compiler to determine the
1518 exact set of local variables in the outer scope, which makes it
1519 impossible to determine the bindings for free variables in the
1520 inner scope. To avoid the warning about import *, change it into
1521 an import of explicitly name object, or move the import* statement
1522 to the global scope; to avoid the warning about bare exec, use
1523 exec...in... (a good idea anyway -- there's a possibility that
1524 bare exec will be deprecated in the future).
1525
1526 - Use of a global variable in a nested scope with the same name as a
1527 local variable in a surrounding scope. This will change in
1528 meaning with nested scopes: the name in the inner scope will
1529 reference the variable in the outer scope rather than the global
1530 of the same name. To avoid the warning, either rename the outer
1531 variable, or use a global statement in the inner function.
1532
Neil Schemenauera35c6882001-02-27 04:45:05 +00001533- An optional object allocator has been included. This allocator is
1534 optimized for Python objects and should be faster and use less memory
1535 than the standard system allocator. It is not enabled by default
1536 because of possible thread safety problems. The allocator is only
1537 protected by the Python interpreter lock and it is possible that some
1538 extension modules require a thread safe allocator. The object
1539 allocator can be enabled by providing the "--with-pymalloc" option to
1540 configure.
1541
Tim Petersd66595f2001-02-04 03:09:53 +00001542Standard library
1543
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001544- pyexpat now detects the expat version if expat.h defines it. A
1545 number of additional handlers are provided, which are only available
1546 since expat 1.95. In addition, the methods SetParamEntityParsing and
1547 GetInputContext of Parser objects are available with 1.95.x
1548 only. Parser objects now provide the ordered_attributes and
1549 specified_attributes attributes. A new module expat.model was added,
1550 which offers a number of additional constants if 1.95.x is used.
1551
1552- xml.dom offers the new functions registerDOMImplementation and
1553 getDOMImplementation.
1554
1555- xml.dom.minidom offers a toprettyxml method. A number of DOM
1556 conformance issues have been resolved. In particular, Element now
1557 has an hasAttributes method, and the handling of namespaces was
1558 improved.
1559
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001560- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1561 getting information about live Python code, and pydoc.py, a module
1562 for interactively converting docstrings to HTML or text.
1563 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001564 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001565 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1566 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001567
Tim Peters1eff7962001-03-01 02:31:33 +00001568- New library module difflib.py, primarily packaging the SequenceMatcher
1569 class at the heart of the popular ndiff.py file-comparison tool.
1570
1571- doctest.py (a framework for verifying Python code examples in docstrings)
1572 is now part of the std library.
1573
Tim Petersd66595f2001-02-04 03:09:53 +00001574Windows changes
1575
Guido van Rossume3955a82001-03-02 14:05:59 +00001576- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1577 small GUI that lets you browse the module docstrings using your
1578 default web browser.
1579
Tim Peters1eff7962001-03-01 02:31:33 +00001580- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1581 Platforms) is implemented. See
1582
1583 http://python.sourceforge.net/peps/pep-0235.html
1584
1585 for full details, especially the "Current Lower-Left Semantics" section.
1586 The new Windows import rules are simpler than before:
1587
1588 A. If the PYTHONCASEOK environment variable exists, same as
1589 before: silently accept the first case-insensitive match of any
1590 kind; raise ImportError if none found.
1591
1592 B. Else search sys.path for the first case-sensitive match; raise
1593 ImportError if none found.
1594
1595 The same rules have been implented on other platforms with case-
1596 insensitive but case-preserving filesystems too (including Cygwin, and
1597 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001598
Tim Peters25a9ce32001-02-19 07:06:36 +00001599- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1600 what it's supposed to do (and does do under NT and 2000) via direct
1601 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001602 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001603 all Win9x systems before.
1604
Tim Peters1eff7962001-03-01 02:31:33 +00001605- Build: Subproject _test (effectively) renamed to _testcapi.
1606
Tim Peters2fe289a2001-03-01 22:19:38 +00001607New platforms
1608
1609- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1610 Thanks to Steven Majewski!
1611
1612- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1613 Tishler!
1614
Guido van Rossum9089b272001-03-02 06:49:50 +00001615- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1616 Schwertberger! See RISCOS/README for more information -- it seems
1617 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001618 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001619
Tim Peters25a9ce32001-02-19 07:06:36 +00001620
Tim Petersd7b5e882001-01-25 03:36:26 +00001621What's New in Python 2.1 alpha 2?
1622=================================
Tim Peters40ead762001-01-27 05:35:26 +00001623
Tim Petersd7b5e882001-01-25 03:36:26 +00001624Core language, builtins, and interpreter
1625
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001626- Scopes nest. If a name is used in a function or class, but is not
1627 local, the definition in the nearest enclosing function scope will
1628 be used. One consequence of this change is that lambda statements
1629 could reference variables in the namespaces where the lambda is
1630 defined. In some unusual cases, this change will break code.
1631
1632 In all previous version of Python, names were resolved in exactly
1633 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001634 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001635 function A is defined within a function B, the names bound in B are
1636 not visible in A. The new rules make names bound in B visible in A,
1637 unless A contains a name binding that hides the binding in B.
1638
1639 Section 4.1 of the reference manual describes the new scoping rules
1640 in detail. The test script in Lib/test/test_scope.py demonstrates
1641 some of the effects of the change.
1642
1643 The new rules will cause existing code to break if it defines nested
1644 functions where an outer function has local variables with the same
1645 name as globals or builtins used by the inner function. Example:
1646
1647 def munge(str):
1648 def helper(x):
1649 return str(x)
1650 if type(str) != type(''):
1651 str = helper(str)
1652 return str.strip()
1653
1654 Under the old rules, the name str in helper() is bound to the
1655 builtin function str(). Under the new rules, it will be bound to
1656 the argument named str and an error will occur when helper() is
1657 called.
1658
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001659- The compiler will report a SyntaxError if "from ... import *" occurs
1660 in a function or class scope. The language reference has documented
1661 that this case is illegal, but the compiler never checked for it.
1662 The recent introduction of nested scope makes the meaning of this
1663 form of name binding ambiguous. In a future release, the compiler
1664 may allow this form when there is no possibility of ambiguity.
1665
Tim Peters40ead762001-01-27 05:35:26 +00001666- repr(string) is easier to read, now using hex escapes instead of octal,
1667 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1668
1669 >>> "\texample \r\n" + chr(0) + chr(255)
1670 '\texample \r\n\x00\xff' # in 2.1
1671 '\011example \015\012\000\377' # in 2.0
1672
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001673- Functions are now compared and hashed by identity, not by value, since
1674 the func_code attribute is writable.
1675
Fred Drakefb9d7122001-02-01 20:00:40 +00001676- Weak references (PEP 205) have been added. This involves a few
1677 changes in the core, an extension module (_weakref), and a Python
1678 module (weakref). The weakref module is the public interface. It
1679 includes support for "explicit" weak references, proxy objects, and
1680 mappings with weakly held values.
1681
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001682- A 'continue' statement can now appear in a try block within the body
1683 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001684 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001685
Tim Petersd7b5e882001-01-25 03:36:26 +00001686Standard library
1687
Barry Warsaw30dbd142001-01-31 22:14:01 +00001688- mailbox.py now has a new class, PortableUnixMailbox which is
1689 identical to UnixMailbox but uses a more portable scheme for
1690 determining From_ separators. Also, the constructors for all the
1691 classes in this module have a new optional `factory' argument, which
1692 is a callable used when new message classes must be instantiated by
1693 the next() method.
1694
Tim Petersd7b5e882001-01-25 03:36:26 +00001695- random.py is now self-contained, and offers all the functionality of
1696 the now-deprecated whrandom.py. See the docs for details. random.py
1697 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001698 and restoring the internal state of the generator; and jumpahead(n),
1699 for quickly forcing the internal state to be the same as if n calls to
1700 random() had been made. The latter is particularly useful for multi-
1701 threaded programs, creating one instance of the random.Random() class for
1702 each thread, then using .jumpahead() to force each instance to use a
1703 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001704
Tim Peters0de88fc2001-02-01 04:59:18 +00001705- random.py's seed() function is new. For bit-for-bit compatibility with
1706 prior releases, use the whseed function instead. The new seed function
1707 addresses two problems: (1) The old function couldn't produce more than
1708 about 2**24 distinct internal states; the new one about 2**45 (the best
1709 that can be done in the Wichmann-Hill generator). (2) The old function
1710 sometimes produced identical internal states when passed distinct
1711 integers, and there was no simple way to predict when that would happen;
1712 the new one guarantees to produce distinct internal states for all
1713 arguments in [0, 27814431486576L).
1714
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001715- The socket module now supports raw packets on Linux. The socket
1716 family is AF_PACKET.
1717
Tim Peters9ea17ac2001-02-02 05:57:15 +00001718- test_capi.py is a start at running tests of the Python C API. The tests
1719 are implemented by the new Modules/_testmodule.c.
1720
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001721- A new extension module, _symtable, provides provisional access to the
1722 internal symbol table used by the Python compiler. A higher-level
1723 interface will be added on top of _symtable in a future release.
1724
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001725- Removed the obsolete soundex module.
1726
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001727- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1728 the isSameNode method; NamedNodeMap the get method.
1729
1730- xml.sax.expatreader supports the lexical handler property; it
1731 generates comment, startCDATA, and endCDATA events.
1732
Tim Petersee826f82001-01-31 19:39:44 +00001733Windows changes
1734
1735- Build procedure: the zlib project is built in a different way that
1736 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001737 the zlib binary used. See PCbuild\readme.txt for details. Your old
1738 zlib-related directories can be deleted; you'll need to download fresh
1739 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001740
Tim Peters9ea17ac2001-02-02 05:57:15 +00001741- Build: New subproject _test for the benefit of test_capi.py (see above).
1742
Tim Petersb16c56f2001-02-02 21:24:51 +00001743- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1744 interface to some Python compiler internals).
1745
1746- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001747 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001748
Tim Petersa3a3a032000-11-30 05:22:44 +00001749What's New in Python 2.1 alpha 1?
1750=================================
1751
1752Core language, builtins, and interpreter
1753
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001754- There is a new Unicode companion to the PyObject_Str() API
1755 called PyObject_Unicode(). It behaves in the same way as the
1756 former, but assures that the returned value is an Unicode object
1757 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001758
Guido van Rossumf98eda02001-01-17 15:54:45 +00001759- The comparison operators support "rich comparison overloading" (PEP
1760 207). C extension types can provide a rich comparison function in
1761 the new tp_richcompare slot in the type object. The cmp() function
1762 and the C function PyObject_Compare() first try the new rich
1763 comparison operators before trying the old 3-way comparison. There
1764 is also a new C API PyObject_RichCompare() (which also falls back on
1765 the old 3-way comparison, but does not constrain the outcome of the
1766 rich comparison to a Boolean result).
1767
1768 The rich comparison function takes two objects (at least one of
1769 which is guaranteed to have the type that provided the function) and
1770 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1771 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1772 object, which may be NotImplemented (in which case the tp_compare
1773 slot function is used as a fallback, if defined).
1774
1775 Classes can overload individual comparison operators by defining one
1776 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001777 __ge__. There are no explicit "reflected argument" versions of
1778 these; instead, __lt__ and __gt__ are each other's reflection,
1779 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1780 reflection (similar at the C level). No other implications are
1781 made; in particular, Python does not assume that == is the Boolean
1782 inverse of !=, or that < is the Boolean inverse of >=. This makes
1783 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001784
1785 Classes or types that want to implement (in)equality tests but not
1786 the ordering operators (i.e. unordered types) should implement ==
1787 and !=, and raise an error for the ordering operators.
1788
Guido van Rossuma88479f2001-01-18 14:28:08 +00001789 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001790 Boolean; e.g. a matrix type might want to return a matrix of bits
1791 for A < B, giving elementwise comparisons. Such types should ensure
1792 that any interpretation of their value in a Boolean context raises
1793 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1794 at the C level) to always raise an exception.
1795
Guido van Rossuma88479f2001-01-18 14:28:08 +00001796- Complex numbers use rich comparisons to define == and != but raise
1797 an exception for <, <=, > and >=. Unfortunately, this also means
1798 that cmp() of two complex numbers raises an exception when the two
1799 numbers differ. Since it is not mathematically meaningful to compare
1800 complex numbers except for equality, I hope that this doesn't break
1801 too much code.
1802
Tim Peters3389f192001-02-18 08:48:49 +00001803- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001804 not defined by the language, other than that it's arbitrary but
1805 consistent (see the Reference Manual). An implementation detail changed
1806 in 2.1a1 such that None now compares less than any other object. Code
1807 relying on this new behavior (like code that relied on the previous
1808 behavior) does so at its own risk.
1809
Barry Warsaw573b5412001-01-15 20:43:18 +00001810- Functions and methods now support getting and setting arbitrarily
1811 named attributes (PEP 232). Functions have a new __dict__
1812 (a.k.a. func_dict) which hold the function attributes. Methods get
1813 and set attributes on their underlying im_func. It is a TypeError
1814 to set an attribute on a bound method.
1815
Guido van Rossum051e3352001-01-15 19:11:10 +00001816- The xrange() object implementation has been improved so that
1817 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1818 limitation that in this case len(xrange(sys.maxint)) can't be
1819 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1820 work fine as long as the index i doesn't actually reach 2**31.
1821 (Python uses regular ints for sequence and string indices; fixing
1822 that is much more work.)
1823
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001824- Two changes to from...import:
1825
Guido van Rossumba381232001-02-03 15:06:40 +00001826 1) "from M import X" now works even if (after loading module M)
1827 sys.modules['M'] is not a real module; it's basically a getattr()
1828 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001829
1830 2) "from M import *" now looks for M.__all__ to decide which names to
1831 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1832 filters out names starting with '_' as before. Whether or not
1833 __all__ exists, there's no restriction on the type of M.
1834
Guido van Rossumf61f1662001-01-10 20:13:55 +00001835- File objects have a new method, xreadlines(). This is the fastest
1836 way to iterate over all lines in a file:
1837
1838 for line in file.xreadlines():
1839 ...do something to line...
1840
1841 See the xreadlines module (mentioned below) for how to do this for
1842 other file-like objects.
1843
1844- Even if you don't use file.xreadlines(), you may expect a speedup on
1845 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001846 quite a bit in platform-specific ways: on systems (like Linux) that
1847 support flockfile(), getc_unlocked(), and funlockfile(), those are
1848 used by default. On systems (like Windows) without getc_unlocked(),
1849 a complicated (but still thread-safe) method using fgets() is used by
1850 default.
1851
Tim Petersd52269b2001-01-25 06:23:18 +00001852 You can force use of the fgets() method by #define'ing
1853 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001854 getc_unlocked()).
1855
Tim Petersd52269b2001-01-25 06:23:18 +00001856 You can force fgets() not to be used by #define'ing
1857 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001858 test_bufio.py fails -- and let us know if it does!).
1859
1860- In addition, the fileinput module, while still slower than the other
1861 methods on most platforms, has been sped up too, by using
1862 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001863
1864- Support for run-time warnings has been added, including a new
1865 command line option (-W) to specify the disposition of warnings.
1866 See the description of the warnings module below.
1867
1868- Extensive changes have been made to the coercion code. This mostly
1869 affects extension modules (which can now implement mixed-type
1870 numerical operators without having to use coercion), but
1871 occasionally, in boundary cases the coercion semantics have changed
1872 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001873 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001874 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001875 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001876
Guido van Rossumf98eda02001-01-17 15:54:45 +00001877- In connection with the coercion changes, a new built-in singleton
1878 object, NotImplemented is defined. This can be returned for
1879 operations that wish to indicate they are not implemented for a
1880 particular combination of arguments. From C, this is
1881 Py_NotImplemented.
1882
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001883- The interpreter accepts now bytecode files on the command line even
1884 if they do not have a .pyc or .pyo extension. On Linux, after executing
1885
Martin v. Löwise214baa2001-02-04 22:37:56 +00001886import imp,sys,string
1887magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1888reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1889open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001890
1891 any byte code file can be used as an executable (i.e. as an argument
1892 to execve(2)).
1893
Tim Peters9940b802000-12-01 07:59:35 +00001894- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001895 character. In 1.6 and earlier, they never produced a sign,
1896 and raised an error if the value of the long was too large
1897 to fit in a Python int. In 2.0, they produced a sign if and
1898 only if too large to fit in an int. This was inconsistent
1899 across platforms (because the size of an int varies across
1900 platforms), and inconsistent with hex() and oct(). Example:
1901
1902 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001903 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001904 'ffffffbe' # in 2.0 and before, on 32-bit machines
1905 >>> hex(-0x42L)
1906 '-0x42L' # in all versions of Python
1907
Tim Peters9940b802000-12-01 07:59:35 +00001908 The behavior of %d formats for negative Python longs remains
1909 the same as in 2.0 (although in 1.6 and before, they raised
1910 an error if the long didn't fit in a Python int).
1911
1912 %u formats don't make sense for Python longs, but are allowed
1913 and treated the same as %d in 2.1. In 2.0, a negative long
1914 formatted via %u produced a sign if and only if too large to
1915 fit in an int. In 1.6 and earlier, a negative long formatted
1916 via %u raised an error if it was too big to fit in an int.
1917
Guido van Rossum3661d392000-12-12 22:10:31 +00001918- Dictionary objects have an odd new method, popitem(). This removes
1919 an arbitrary item from the dictionary and returns it (in the form of
1920 a (key, value) pair). This can be useful for algorithms that use a
1921 dictionary as a bag of "to do" items and repeatedly need to pick one
1922 item. Such algorithms normally end up running in quadratic time;
1923 using popitem() they can usually be made to run in linear time.
1924
Tim Peters36cdad12000-12-29 02:06:45 +00001925Standard library
1926
Thomas Woutersfe385252001-01-19 23:16:56 +00001927- In the time module, the time argument to the functions strftime,
1928 localtime, gmtime, asctime and ctime is now optional, defaulting to
1929 the current time (in the local timezone).
1930
Guido van Rossumda91f222001-01-15 16:36:08 +00001931- The ftplib module now defaults to passive mode, which is deemed a
1932 more useful default given that clients are often inside firewalls
1933 these days. Note that this could break if ftplib is used to connect
1934 to a *server* that is inside a firewall, from outside; this is
1935 expected to be a very rare situation. To fix that, you can call
1936 ftp.set_pasv(0).
1937
Martin v. Löwis10a27872001-01-13 09:54:41 +00001938- The module site now treats .pth files not only for path configuration,
1939 but also supports extensions to the initialization code: Lines starting
1940 with import are executed.
1941
Guido van Rossumf61f1662001-01-10 20:13:55 +00001942- There's a new module, warnings, which implements a mechanism for
1943 issuing and filtering warnings. There are some new built-in
1944 exceptions that serve as warning categories, and a new command line
1945 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1946 turns warnings into errors). warnings.warn(message[, category])
1947 issues a warning message; this can also be called from C as
1948 PyErr_Warn(category, message).
1949
1950- A new module xreadlines was added. This exports a single factory
1951 function, xreadlines(). The intention is that this code is the
1952 absolutely fastest way to iterate over all lines in an open
1953 file(-like) object:
1954
1955 import xreadlines
1956 for line in xreadlines.xreadlines(file):
1957 ...do something to line...
1958
1959 This is equivalent to the previous the speed record holder using
1960 file.readlines(sizehint). Note that if file is a real file object
1961 (as opposed to a file-like object), this is equivalent:
1962
1963 for line in file.xreadlines():
1964 ...do something to line...
1965
Tim Peters36cdad12000-12-29 02:06:45 +00001966- The bisect module has new functions bisect_left, insort_left,
1967 bisect_right and insort_right. The old names bisect and insort
1968 are now aliases for bisect_right and insort_right. XXX_right
1969 and XXX_left methods differ in what happens when the new element
1970 compares equal to one or more elements already in the list: the
1971 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001972 right. Code that doesn't care where equal elements end up should
1973 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001974
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001975- The new curses.panel module wraps the panel library that forms part
1976 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1977
Guido van Rossumf61f1662001-01-10 20:13:55 +00001978- The SocketServer module now sets the allow_reuse_address flag by
1979 default in the TCPServer class.
1980
1981- A new function, sys._getframe(), returns the stack frame pointer of
1982 the caller. This is intended only as a building block for
1983 higher-level mechanisms such as string interpolation.
1984
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001985- The pyexpat module supports a number of new handlers, which are
1986 available only in expat 1.2. If invocation of a callback fails, it
1987 will report an additional frame in the traceback. Parser objects
1988 participate now in garbage collection. If expat reports an unknown
1989 encoding, pyexpat will try to use a Python codec; that works only
1990 for single-byte charsets. The parser type objects is exposed as
1991 XMLParserObject.
1992
1993- xml.dom now offers standard definitions for symbolic node type and
1994 exception code constants, and a hierarchy of DOM exceptions. minidom
1995 was adjusted to use them.
1996
1997- The conformance of xml.dom.minidom to the DOM specification was
1998 improved. It detects a number of additional error cases; the
1999 previous/next relationship works even when the tree is modified;
2000 Node supports the normalize() method; NamedNodeMap, DocumentType and
2001 DOMImplementation classes were added; Element supports the
2002 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2003 method.
2004
Guido van Rossumf61f1662001-01-10 20:13:55 +00002005Build issues
2006
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002007- For Unix (and Unix-compatible) builds, configuration and building of
2008 extension modules is now greatly automated. Rather than having to
2009 edit the Modules/Setup file to indicate which modules should be
2010 built and where their include files and libraries are, a
2011 distutils-based setup.py script now takes care of building most
2012 extension modules. All extension modules built this way are built
2013 as shared libraries. Only a few modules that must be linked
2014 statically are still listed in the Setup file; you won't need to
2015 edit their configuration.
2016
2017- Python should now build out of the box on Cygwin. If it doesn't,
2018 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002019
2020- Python now always uses its own (renamed) implementation of getopt()
2021 -- there's too much variation among C library getopt()
2022 implementations.
2023
2024- C++ compilers are better supported; the CXX macro is always set to a
2025 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002026
Tim Petersd92dfe02000-12-12 01:18:41 +00002027Windows changes
2028
2029- select module: By default under Windows, a select() call
2030 can specify no more than 64 sockets. Python now boosts
2031 this Microsoft default to 512. If you need even more than
2032 that, see the MS docs (you'll need to #define FD_SETSIZE
2033 and recompile Python from source).
2034
Guido van Rossumf61f1662001-01-10 20:13:55 +00002035- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2036 subdirectory is no more!
2037
Tim Petersa3a3a032000-11-30 05:22:44 +00002038
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002039What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002040=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002041
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002042Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002043changes are in the file HISTORY. If you are making the jump directly
2044from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2045HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002046
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002047Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2048the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2049http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002050
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002051--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002052
2053======================================================================
2054
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002055What's new in 2.0 (since release candidate 1)?
2056==============================================
2057
2058Standard library
2059
2060- The copy_reg module was modified to clarify its intended use: to
2061 register pickle support for extension types, not for classes.
2062 pickle() will raise a TypeError if it is passed a class.
2063
2064- Fixed a bug in gettext's "normalize and expand" code that prevented
2065 it from finding an existing .mo file.
2066
2067- Restored support for HTTP/0.9 servers in httplib.
2068
Tim Peters989b7b92000-10-16 20:24:53 +00002069- The math module was changed to stop raising OverflowError in case of
2070 underflow, and return 0 instead in underflow cases. Whether Python
2071 used to raise OverflowError in case of underflow was platform-
2072 dependent (it did when the platform math library set errno to ERANGE
2073 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002074
2075- Fixed a bug in StringIO that occurred when the file position was not
2076 at the end of the file and write() was called with enough data to
2077 extend past the end of the file.
2078
2079- Fixed a bug that caused Tkinter error messages to get lost on
2080 Windows. The bug was fixed by replacing direct use of
2081 interp->result with Tcl_GetStringResult(interp).
2082
2083- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2084 redirect response.
2085
2086- Several changes were made to distutils: Some debugging code was
2087 removed from util. Fixed the installer used when an external zip
2088 program (like WinZip) is not found; the source code for this
2089 installer is in Misc/distutils. check_lib() was modified to behave
2090 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2091 test for whether installed modules are on sys.path was changed to
2092 use both normcase() and normpath().
2093
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002094- Several minor bugs were fixed in the xml package (the minidom,
2095 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002096
2097- The regression test driver (regrtest.py) behavior when invoked with
2098 -l changed: It now reports a count of objects that are recognized as
2099 garbage but not freed by the garbage collector.
2100
Tim Peters989b7b92000-10-16 20:24:53 +00002101- The regression test for the math module was changed to test
2102 exceptional behavior when the test is run in verbose mode. Python
2103 cannot yet guarantee consistent exception behavior across platforms,
2104 so the exception part of test_math is run only in verbose mode, and
2105 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002106
2107Internals
2108
2109- PyOS_CheckStack() has been disabled on Win64, where it caused
2110 test_sre to fail.
2111
2112Build issues
2113
2114- Changed compiler flags, so that gcc is always invoked with -Wall and
2115 -Wstrict-prototypes. Users compiling Python with GCC should see
2116 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002117 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002118 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002119
Tim Petersa3a3a032000-11-30 05:22:44 +00002120- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002121
2122Tools and other miscellany
2123
2124- The compiler in Tools/compiler was updated to support the new
2125 language features introduced in 2.0: extended print statement, list
2126 comprehensions, and augmented assignments. The new compiler should
2127 also be backwards compatible with Python 1.5.2; the compiler will
2128 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002129 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002130
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002131What's new in 2.0 release candidate 1 (since beta 2)?
2132=====================================================
2133
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002134What is release candidate 1?
2135
2136We believe that release candidate 1 will fix all known bugs that we
2137intend to fix for the 2.0 final release. This release should be a bit
2138more stable than the previous betas. We would like to see even more
2139widespread testing before the final release, so we are producing this
2140release candidate. The final release will be exactly the same unless
2141any show-stopping (or brown bag) bugs are found by testers of the
2142release candidate.
2143
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002144All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002145to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002146
2147Core language, builtins, and interpreter
2148
2149- A bug that caused crashes when __coerce__ was used with augmented
2150 assignment, e.g. +=, was fixed.
2151
2152- Raise ZeroDivisionError when raising zero to a negative number,
2153 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2154 power operator and the result of math.pow(0.0, -2.0) will vary by
2155 platform. On Linux, it raises a ValueError.
2156
2157- A bug in Unicode string interpolation was fixed that occasionally
2158 caused errors with formats including "%%". For example, the
2159 following expression "%% %s" % u"abc" no longer raises a TypeError.
2160
2161- Compilation of deeply nested expressions raises MemoryError instead
2162 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2163
2164- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2165 rendering them useless. They are now written in binary mode again.
2166
2167Standard library
2168
2169- Keyword arguments are now accepted for most pattern and match object
2170 methods in SRE, the standard regular expression engine.
2171
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002172- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002173 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002174
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002175- Several bugs in the Unicode handling and error handling in _tkinter
2176 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002177
2178- Fix memory management errors in Merge() and Tkapp_Call() routines.
2179
2180- Several changes were made to cStringIO to make it compatible with
2181 the file-like object interface and with StringIO. If operations are
2182 performed on a closed object, an exception is raised. The truncate
2183 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002184 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002185
2186- There were many changes made to the linuxaudiodev module and its
2187 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002188 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002189
2190 Note that this module is named poorly, because it should work
2191 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002192 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002193
2194 The module now raises exceptions when errors occur instead of
2195 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2196 audio) and defines a getptr() method that calls the
2197 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2198
2199- The library_version attribute, introduced in an earlier beta, was
2200 removed because it can not be supported with early versions of the C
2201 readline library, which provides no way to determine the version at
2202 compile-time.
2203
2204- The binascii module is now enabled on Win64.
2205
Tim Peters46446d62000-10-09 21:19:31 +00002206- tokenize.py no longer suffers "recursion depth" errors when parsing
2207 programs with very long string literals.
2208
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002209Internals
2210
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002211- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002212 which is called when the interpreter starts up to determine where
2213 the standard library is installed. These vulnerabilities affect all
2214 previous versions of Python and can be exploited by setting very
2215 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2216 setuid Python script, although use of the wrapper in
2217 Misc/setuid-prog.c will eliminate the vulnerability.
2218
2219- Fixed garbage collection bugs in instance creation that were
2220 triggered when errors occurred during initialization. The solution,
2221 applied in cPickle and in PyInstance_New(), is to call
2222 PyObject_GC_Init() after the initialization of the object's
2223 container attributes is complete.
2224
2225- pyexpat adds definitions of PyModule_AddStringConstant and
2226 PyModule_AddObject if the Python version is less than 2.0, which
2227 provides compatibility with PyXML on Python 1.5.2.
2228
2229- If the platform has a bogus definition for LONG_BIT (the number of
2230 bits in a long), an error will be reported at compile time.
2231
2232- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2233 collection crashes and possibly other, unreported crashes.
2234
2235- Fixed a memory leak in _PyUnicode_Fini().
2236
2237Build issues
2238
2239- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002240 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002241 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002242
2243- The mmap.PAGESIZE constant is now initialized using sysconf when
2244 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2245
2246- The md5 file should now compile on all platforms.
2247
2248- The select module now compiles on platforms that do not define
2249 POLLRDNORM and related constants.
2250
2251- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002252 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002253
Jeremy Hylton10921202000-10-09 18:34:12 +00002254- BeOS: A number of changes were made to the build and installation
2255 process. ar-fake now operates on a directory of object files.
2256 dl_export.h is gone, and its macros now appear on the mwcc command
2257 line during build on PPC BeOS.
2258
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002259- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002260 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002261
2262- Cygwin: Support for shared libraries, Tkinter, and sockets.
2263
2264- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2265
2266Tools and other miscellany
2267
2268- Removed debugging prints from main used with freeze.
2269
Tim Peters46446d62000-10-09 21:19:31 +00002270- IDLE auto-indent no longer crashes when it encounters Unicode
2271 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002272
2273What's new in 2.0 beta 2 (since beta 1)?
2274========================================
2275
2276Core language, builtins, and interpreter
2277
Tim Peters482c0212000-09-26 06:33:09 +00002278- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002279 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002280
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002281- Add -h and -V command line options to print the usage message and
2282 Python version number and exit immediately.
2283
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002284- eval() and exec accept Unicode objects as code parameters.
2285
2286- getattr() and setattr() now also accept Unicode objects for the
2287 attribute name, which are converted to strings using the default
2288 encoding before lookup.
2289
2290- Multiplication on string and Unicode now does proper bounds
2291 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2292 string is too long."
2293
2294- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002295 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002296
Jeremy Hylton1b618592000-09-26 05:32:36 +00002297
2298Standard library and extensions
2299
Guido van Rossum5b08f132001-04-16 02:05:23 +00002300- socket module: the OpenSSL code now adds support for RAND_status()
2301 and EGD (Entropy Gathering Device).
2302
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002303- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002304 argument checking; it still takes no arguments.
2305
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002306- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002307
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002308- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002309
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002310- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002311
2312- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002313 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002314
2315- copy: Copy Unicode objects atomically.
2316
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002317- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002318
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002319- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002320
Fred Drake67233bc2000-09-26 16:40:27 +00002321- dbm: Add get() and setdefault() methods to dbm object. Add constant
2322 `library' to module that names the library used. Added doc strings
2323 and method names to error messages. Uses configure to determine
2324 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2325 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002326
2327- distutils: Update to version 0.9.3.
2328
2329- dl: Add several dl.RTLD_ constants.
2330
2331- fpectl: Now supported on FreeBSD.
2332
2333- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2334 found by the collector will be saved in gc.garbage. This is useful
2335 for debugging a program that creates reference cycles.
2336
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002337- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002338 of HTTP class. Do not close socket on zero-length response. Do not
2339 crash when server sends invalid content-length header.
2340
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002341- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002342
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002343- marshal: When reading a short, sign-extend on platforms where shorts
2344 are bigger than 16 bits. When reading a long, repair the unportable
2345 sign extension that was being done for 64-bit machines. (It assumed
2346 that signed right shift sign-extends.)
2347
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002348- operator: Add contains(), invert(), __invert__() as aliases for
2349 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002350
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002351- os: Add support for popen2() and popen3() on all platforms where
2352 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002353
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002354- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002355 clicking on a file in Explorer (or passing the file name to the
2356 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002357
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002358- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002359 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002360
2361- pickle: Now raises ValueError when an invalid pickle that contains
2362 a non-string repr where a string repr was expected. This behavior
2363 matches cPickle.
2364
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002365- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002366
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002367- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002368
2369- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002370 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002371 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002372
2373- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002374 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002375
2376- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002377 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002378 few cycles during startup since the first call to
2379 setdefaultencoding() will initialize the codec registry and the
2380 encodings package.
2381
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002382- socket: Support for size hint in readlines() method of object returned
2383 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002384
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002385- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002386 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002387 is followed by whitespace.
2388
Tim Petersa3a3a032000-11-30 05:22:44 +00002389- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002390
2391- struct: Check ranges for bytes and shorts.
2392
2393- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002394 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002395
2396- Tkinter: Image objects are now guaranteed to have unique ids. Set
2397 event.delta to zero if Tk version doesn't support mousewheel.
2398 Removed some debugging prints.
2399
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002400- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002401
Fred Drake67233bc2000-09-26 16:40:27 +00002402- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002403 which works around a bug in Norton AntiVirus 2000 that leads directly
2404 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002405
2406- xml: New version detection code allows PyXML to override standard
2407 XML package if PyXML version is greater than 0.6.1.
2408
Fred Drake64bb3802000-09-26 16:21:35 +00002409- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2410 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2411 tree only for nodes which are sufficiently interesting to a specific
2412 application. Does not provide the HTML-specific extensions. Still
2413 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002414
Fred Drake64bb3802000-09-26 16:21:35 +00002415- xml.sax: SAX 2 support for Python, including all the handler
2416 interfaces needed to process XML 1.0 compliant XML. Some
2417 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002418
Fred Drake64bb3802000-09-26 16:21:35 +00002419- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2420 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002421
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002422
Jeremy Hylton1b618592000-09-26 05:32:36 +00002423C API
2424
2425- Add three new convenience functions for module initialization --
2426 PyModule_AddObject(), PyModule_AddIntConstant(), and
2427 PyModule_AddStringConstant().
2428
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002429- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002430 removed and add #error to Python.h if NULL isn't defined after
2431 #include of stdio.h.
2432
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002433- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002434 backwards compatibility (at the source level) with old extensions.
2435
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002436- A wrapper API was added for signal() and sigaction(). Instead of
2437 either function, always use PyOS_getsig() to get a signal handler
2438 and PyOS_setsig() to set one. A new convenience typedef
2439 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002440
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002441- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002442 internal data buffer and size of a string object -- or the default
2443 encoded version of a Unicode object.
2444
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002445- PyString_Size() and PyString_AsString() accept Unicode objects.
2446
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002447- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002448 exists). INT_MAX and LONG_MAX will always be defined, even if
2449 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002450
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002451- PyFloat_FromString takes a second argument, pend, that was
2452 effectively useless. It is now officially useless but preserved for
2453 backwards compatibility. If the pend argument is not NULL, *pend is
2454 set to NULL.
2455
2456- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2457 for the attribute name. See note on getattr() above.
2458
2459- A few bug fixes to argument processing for Unicode.
2460 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2461 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2462 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002463 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002464
2465- Py_BuildValue accepts B format (for bgen-generated code).
2466
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002467
Jeremy Hylton1b618592000-09-26 05:32:36 +00002468Internals
2469
2470- On Unix, fix code for finding Python installation directory so that
2471 it works when argv[0] is a relative path.
2472
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002473- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002474 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002475 rather than by generating a copy of the object.
2476
Tim Peters482c0212000-09-26 06:33:09 +00002477- Several of the internal Unicode tables are much smaller now, and
2478 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002479
Jeremy Hylton97693b02000-09-26 17:42:51 +00002480- In the garbage collector: Fixed bug in collection of tuples. Fixed
2481 bug that caused some instances to be removed from the container set
2482 while they were still live. Fixed parsing in gc.set_debug() for
2483 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002484
2485- Fixed refcount problem in instance deallocation that only occurred
2486 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2487
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002488- On Windows, getpythonregpath is now protected against null data in
2489 registry key.
2490
2491- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002492 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002493
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002494
Jeremy Hylton1b618592000-09-26 05:32:36 +00002495Build and platform-specific issues
2496
2497- Better support of GNU Pth via --with-pth configure option.
2498
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002499- Python/C API now properly exposed to dynamically-loaded extension
2500 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002501
2502- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2503 Don't define MS_SYNC to be zero when it is undefined. Added missing
2504 prototypes in posixmodule.c.
2505
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002506- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002507 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002508
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002509- Fix largefile support on older NetBSD systems and OpenBSD by adding
2510 define for TELL64.
2511
2512
2513Tools and other miscellany
2514
2515- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2516
2517- freeze: The modulefinder now works with 2.0 opcodes.
2518
Tim Petersa3a3a032000-11-30 05:22:44 +00002519- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002520 Move hackery of sys.argv until after the Tk instance has been
2521 created, which allows the application-specific Tkinter
2522 initialization to be executed if present; also pass an explicit
2523 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002524
Jeremy Hylton1b618592000-09-26 05:32:36 +00002525
2526What's new in 2.0 beta 1?
2527=========================
2528
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002529Source Incompatibilities
2530------------------------
2531
2532None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2533such as single-argument append(), connect() and bind(), and changes to
2534str(long) and repr(float).
2535
2536
2537Binary Incompatibilities
2538------------------------
2539
2540- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2541with Python 2.0; these extensions will have to be rebuilt for Python
25422.0.
2543
2544- On Windows, attempting to import a third party extension built for
2545Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2546can do about this. Check your PYTHONPATH environment variable!
2547
2548- Python bytecode files (*.pyc and *.pyo) are not compatible between
2549releases.
2550
2551
2552Overview of Changes Since 1.6
2553-----------------------------
2554
2555There are many new modules (including brand new XML support through
2556the xml package, and i18n support through the gettext module); a list
2557of all new modules is included below. Lots of bugs have been fixed.
2558
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002559The process for making major new changes to the language has changed
2560since Python 1.6. Enhancements must now be documented by a Python
2561Enhancement Proposal (PEP) before they can be accepted.
2562
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002563There are several important syntax enhancements, described in more
2564detail below:
2565
2566 - Augmented assignment, e.g. x += 1
2567
2568 - List comprehensions, e.g. [x**2 for x in range(10)]
2569
2570 - Extended import statement, e.g. import Module as Name
2571
2572 - Extended print statement, e.g. print >> file, "Hello"
2573
2574Other important changes:
2575
2576 - Optional collection of cyclical garbage
2577
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002578Python Enhancement Proposal (PEP)
2579---------------------------------
2580
2581PEP stands for Python Enhancement Proposal. A PEP is a design
2582document providing information to the Python community, or describing
2583a new feature for Python. The PEP should provide a concise technical
2584specification of the feature and a rationale for the feature.
2585
2586We intend PEPs to be the primary mechanisms for proposing new
2587features, for collecting community input on an issue, and for
2588documenting the design decisions that have gone into Python. The PEP
2589author is responsible for building consensus within the community and
2590documenting dissenting opinions.
2591
2592The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002593
2594Augmented Assignment
2595--------------------
2596
2597This must have been the most-requested feature of the past years!
2598Eleven new assignment operators were added:
2599
Guido van Rossume905e952000-09-05 12:42:46 +00002600 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002601
2602For example,
2603
2604 A += B
2605
2606is similar to
2607
2608 A = A + B
2609
2610except that A is evaluated only once (relevant when A is something
2611like dict[index].attr).
2612
2613However, if A is a mutable object, A may be modified in place. Thus,
2614if A is a number or a string, A += B has the same effect as A = A+B
2615(except A is only evaluated once); but if a is a list, A += B has the
2616same effect as A.extend(B)!
2617
2618Classes and built-in object types can override the new operators in
2619order to implement the in-place behavior; the not-in-place behavior is
2620used automatically as a fallback when an object doesn't implement the
2621in-place behavior. For classes, the method name is derived from the
2622method name for the corresponding not-in-place operator by inserting
2623an 'i' in front of the name, e.g. __iadd__ implements in-place
2624__add__.
2625
2626Augmented assignment was implemented by Thomas Wouters.
2627
2628
2629List Comprehensions
2630-------------------
2631
2632This is a flexible new notation for lists whose elements are computed
2633from another list (or lists). The simplest form is:
2634
2635 [<expression> for <variable> in <sequence>]
2636
Guido van Rossum56db0952000-09-06 23:34:25 +00002637For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002638This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002639
2640You can also add a condition:
2641
2642 [<expression> for <variable> in <sequence> if <condition>]
2643
2644For example, [w for w in words if w == w.lower()] would yield the list
2645of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002646than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002647
2648You can also have nested for loops and more than one 'if' clause. For
2649example, here's a function that flattens a sequence of sequences::
2650
2651 def flatten(seq):
2652 return [x for subseq in seq for x in subseq]
2653
2654 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2655
2656This prints
2657
2658 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2659
2660List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002661Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002662
2663
2664Extended Import Statement
2665-------------------------
2666
2667Many people have asked for a way to import a module under a different
2668name. This can be accomplished like this:
2669
2670 import foo
2671 bar = foo
2672 del foo
2673
2674but this common idiom gets old quickly. A simple extension of the
2675import statement now allows this to be written as follows:
2676
2677 import foo as bar
2678
2679There's also a variant for 'from ... import':
2680
2681 from foo import bar as spam
2682
2683This also works with packages; e.g. you can write this:
2684
2685 import test.regrtest as regrtest
2686
2687Note that 'as' is not a new keyword -- it is recognized only in this
2688context (this is only possible because the syntax for the import
2689statement doesn't involve expressions).
2690
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002691Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002692
2693
2694Extended Print Statement
2695------------------------
2696
2697Easily the most controversial new feature, this extension to the print
2698statement adds an option to make the output go to a different file
2699than the default sys.stdout.
2700
2701For example, to write an error message to sys.stderr, you can now
2702write:
2703
2704 print >> sys.stderr, "Error: bad dog!"
2705
2706As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002707evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002708
2709 print >> None, "Hello world"
2710
2711is equivalent to
2712
2713 print "Hello world"
2714
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002715Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002716
2717
2718Optional Collection of Cyclical Garbage
2719---------------------------------------
2720
2721Python is now equipped with a garbage collector that can hunt down
2722cyclical references between Python objects. It's no replacement for
2723reference counting; in fact, it depends on the reference counts being
2724correct, and decides that a set of objects belong to a cycle if all
2725their reference counts can be accounted for from their references to
2726each other. This devious scheme was first proposed by Eric Tiedemann,
2727and brought to implementation by Neil Schemenauer.
2728
2729There's a module "gc" that lets you control some parameters of the
2730garbage collection. There's also an option to the configure script
2731that lets you enable or disable the garbage collection. In 2.0b1,
2732it's on by default, so that we (hopefully) can collect decent user
2733experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002734performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002735off by default in the final 2.0 release.
2736
2737
2738Smaller Changes
2739---------------
2740
2741A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2742map(None, seq1, seq2, ...) when the sequences have the same length;
2743i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2744the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002745zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002746
2747sys.version_info is a tuple (major, minor, micro, level, serial).
2748
2749Dictionaries have an odd new method, setdefault(key, default).
2750dict.setdefault(key, default) returns dict[key] if it exists; if not,
2751it sets dict[key] to default and returns that value. Thus:
2752
2753 dict.setdefault(key, []).append(item)
2754
2755does the same work as this common idiom:
2756
2757 if not dict.has_key(key):
2758 dict[key] = []
2759 dict[key].append(item)
2760
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002761There are two new variants of SyntaxError that are raised for
2762indentation-related errors: IndentationError and TabError.
2763
2764Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2765escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002766
2767The limits on the size of expressions and file in Python source code
2768have been raised from 2**16 to 2**32. Previous versions of Python
2769were limited because the maximum argument size the Python VM accepted
2770was 2**16. This limited the size of object constructor expressions,
2771e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2772limit was raised thanks to a patch by Charles Waldman that effectively
2773fixes the problem. It is now much more likely that you will be
2774limited by available memory than by an arbitrary limit in Python.
2775
2776The interpreter's maximum recursion depth can be modified by Python
2777programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2778limit is the maximum number of recursive calls that can be made by
2779Python code. The limit exists to prevent infinite recursion from
2780overflowing the C stack and causing a core dump. The default value is
27811000. The maximum safe value for a particular platform can be found
2782by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002783
2784New Modules and Packages
2785------------------------
2786
2787atexit - for registering functions to be called when Python exits.
2788
2789imputil - Greg Stein's alternative API for writing custom import
2790hooks.
2791
2792pyexpat - an interface to the Expat XML parser, contributed by Paul
2793Prescod.
2794
2795xml - a new package with XML support code organized (so far) in three
2796subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2797would fill a volume. There's a special feature whereby a
2798user-installed package named _xmlplus overrides the standard
2799xmlpackage; this is intended to give the XML SIG a hook to distribute
2800backwards-compatible updates to the standard xml package.
2801
2802webbrowser - a platform-independent API to launch a web browser.
2803
2804
Guido van Rossume905e952000-09-05 12:42:46 +00002805Changed Modules
2806---------------
2807
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002808array -- new methods for array objects: count, extend, index, pop, and
2809remove
2810
2811binascii -- new functions b2a_hex and a2b_hex that convert between
2812binary data and its hex representation
2813
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002814calendar -- Many new functions that support features including control
2815over which day of the week is the first day, returning strings instead
2816of printing them. Also new symbolic constants for days of week,
2817e.g. MONDAY, ..., SUNDAY.
2818
2819cgi -- FieldStorage objects have a getvalue method that works like a
2820dictionary's get method and returns the value attribute of the object.
2821
2822ConfigParser -- The parser object has new methods has_option,
2823remove_section, remove_option, set, and write. They allow the module
2824to be used for writing config files as well as reading them.
2825
2826ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002827optionally support the RFC 959 REST command.
2828
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002829gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002830
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002831httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2832the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002833
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002834locale -- implement getdefaultlocale for Win32 and Macintosh
2835
2836marshal -- no longer dumps core when marshaling deeply nested or
2837recursive data structures
2838
2839os -- new functions isatty, seteuid, setegid, setreuid, setregid
2840
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002841os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2842support under Unix.
2843
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002844os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002845
2846os.path -- fix semantics of os.path.commonprefix
2847
2848smtplib -- support for sending very long messages
2849
2850socket -- new function getfqdn()
2851
2852readline -- new functions to read, write and truncate history files.
2853The readline section of the library reference manual contains an
2854example.
2855
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002856select -- add interface to poll system call
2857
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002858shutil -- new copyfileobj function
2859
2860SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2861HTTP server.
2862
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002863Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002864
2865urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002866e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002867
2868whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002869
2870
2871Obsolete Modules
2872----------------
2873
2874None. However note that 1.6 made a whole slew of modules obsolete:
2875stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2876poly, zmod, strop, util, whatsound.
2877
2878
2879Changed, New, Obsolete Tools
2880----------------------------
2881
Tim Peters8b092332000-09-05 20:15:25 +00002882None.
Guido van Rossume905e952000-09-05 12:42:46 +00002883
2884
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002885C-level Changes
2886---------------
2887
2888Several cleanup jobs were carried out throughout the source code.
2889
2890All C code was converted to ANSI C; we got rid of all uses of the
2891Py_PROTO() macro, which makes the header files a lot more readable.
2892
2893Most of the portability hacks were moved to a new header file,
2894pyport.h; several other new header files were added and some old
2895header files were removed, in an attempt to create a more rational set
2896of header files. (Few of these ever need to be included explicitly;
2897they are all included by Python.h.)
2898
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002899Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002900and Win64, especially for the new Intel Itanium processor. Mick also
2901added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002902
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002903The C APIs to return an object's size have been update to consistently
2904use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2905previous versions, the abstract interfaces used PyXXX_Length and the
2906concrete interfaces used PyXXX_Size. The old names,
2907e.g. PyObject_Length, are still available for backwards compatibility
2908at the API level, but are deprecated.
2909
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002910The PyOS_CheckStack function has been implemented on Windows by
2911Fredrik Lundh. It prevents Python from failing with a stack overflow
2912on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002913
2914The GC changes resulted in creation of two new slots on object,
2915tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002916the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002917
2918The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002919C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002920
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002921PyErr_Format has been updated to automatically calculate the size of
2922the buffer needed to hold the formatted result string. This change
2923prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002924
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002925New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002926
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002927PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2928that are the same as their non-Ex counterparts except they take an
2929extra flag argument that tells them to close the file when done.
2930
2931XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002932
Tim Peters8b092332000-09-05 20:15:25 +00002933
2934Windows Changes
2935---------------
2936
2937New popen2/popen3/peopen4 in os module (see Changed Modules above).
2938
2939os.popen is much more usable on Windows 95 and 98. See Microsoft
2940Knowledge Base article Q150956. The Win9x workaround described there
2941is implemented by the new w9xpopen.exe helper in the root of your
2942Python installation. Note that Python uses this internally; it is not
2943a standalone program.
2944
2945Administrator privileges are no longer required to install Python
2946on Windows NT or Windows 2000. If you have administrator privileges,
2947Python's registry info will be written under HKEY_LOCAL_MACHINE.
2948Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002949under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002950uses of Python, but will prevent some advanced uses from working
2951(for example, running a Python script as an NT service, or possibly
2952from CGI).
2953
2954[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2955installer; instead, it installs the needed Tcl/Tk files directly in the
2956Python directory. If you already have a Tcl/Tk installation, this
2957wastes some disk space (about 4 Megs) but avoids problems with
2958conflicting Tcl/Tk installations, and makes it much easier for Python
2959to ensure that Tcl/Tk can find all its files.
2960
2961[This was new in 1.6] The Windows installer now installs by default in
2962\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2963
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002964
2965Updates to the changes between 1.5.2 and 1.6
2966--------------------------------------------
2967
2968The 1.6 NEWS file can't be changed after the release is done, so here
2969is some late-breaking news:
2970
2971New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2972and changes to getlocale() and setlocale().
2973
2974The new module is now enabled per default.
2975
2976It is not true that the encodings codecs cannot be used for normal
2977strings: the string.encode() (which is also present on 8-bit strings
2978!) allows using them for 8-bit strings too, e.g. to convert files from
2979cp1252 (Windows) to latin-1 or vice-versa.
2980
2981Japanese codecs are available from Tamito KAJIYAMA:
2982http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2983
2984
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002985======================================================================