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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
Martin v. Löwis560da622001-11-24 09:24:51 +000011- gc.get_referents was renamed to gc.get_referrers.
12
Tim Petersb3c9af12001-11-17 00:21:57 +000013Library
14
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +000015- webbrowser defaults to netscape.exe on OS/2 now.
16
Tim Petersb3c9af12001-11-17 00:21:57 +000017Tools/Demos
18
19Build
20
21C API
22
23New platforms
24
25Tests
26
27Windows
28
29Mac
30
31
Tim Peters84362bc2001-10-19 17:55:30 +000032What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000033Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000034===========================
35
36Type/class unification and new-style classes
37
Guido van Rossum3d27df02001-11-15 20:27:54 +000038- Multiple inheritance mixing new-style and classic classes in the
39 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000040
41 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000042 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000043
44 The MRO (method resolution order) for each base class is respected
45 according to its kind, but the MRO for the derived class is computed
46 using new-style MRO rules if any base clase is a new-style class.
47 This needs to be documented.
48
Tim Petersa427a2b2001-10-29 22:25:45 +000049- The new builtin dictionary() constructor, and dictionary type, have
50 been renamed to dict. This reflects a decade of common usage.
51
Guido van Rossum3fc08d22001-11-15 20:33:10 +000052- dict() now accepts an iterable object producing 2-sequences. For
53 example, dict(d.items()) == d for any dictionary d. The argument,
54 and the elements of the argument, can be any iterable objects.
55
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000056- New-style classes can now have a __del__ method, which is called
57 when the instance is deleted (just like for classic classes).
58
Guido van Rossum12d955c2001-10-26 14:56:06 +000059- Assignment to object.__dict__ is now possible, for objects that are
60 instances of new-style classes that have a __dict__ (unless the base
61 class forbids it).
62
Guido van Rossumc8e56452001-10-22 00:43:43 +000063- Methods of built-in types now properly check for keyword arguments
64 (formerly these were silently ignored). The only built-in methods
65 that take keyword arguments are __call__, __init__ and __new__.
66
Guido van Rossum86443212001-10-27 22:28:54 +000067- The socket function has been converted to a type; see below.
68
Tim Peters84362bc2001-10-19 17:55:30 +000069Core and builtins
70
Jeremy Hylton249aaed2001-11-09 21:06:24 +000071- Assignment to __debug__ raises SyntaxError at compile-time. This
72 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +000073 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +000074
Guido van Rossum12d955c2001-10-26 14:56:06 +000075- Clarified the error messages for unsupported operands to an operator
76 (like 1 + '').
77
Tim Peters84362bc2001-10-19 17:55:30 +000078Extension modules
79
Tim Peters5ebfd362001-11-13 23:11:19 +000080- mmap has a new keyword argument, "access", allowing a uniform way for
81 both Windows and Unix users to create read-only, write-through and
82 copy-on-write memory mappings. This was previously possible only on
83 Unix. A new keyword argument was required to support this in a
84 uniform way because the mmap() signuatures had diverged across
85 platforms. Thanks to Jay T Miller for repairing this!
86
Tim Peters169ded02001-11-03 19:57:21 +000087- By default, the gc.garbage list now contains only those instances in
88 unreachable cycles that have __del__ methods; in 2.1 it contained all
89 instances in unreachable cycles. "Instances" here has been generalized
90 to include instances of both new-style and old-style classes.
91
Guido van Rossum12d955c2001-10-26 14:56:06 +000092- The socket module defines a new method for socket objects,
93 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000094 send() until all data has been sent. Also, the socket function has
95 been converted to a subclassable type, like list and tuple (etc.)
96 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000097
98- Various bugfixes to the curses module. There is now a test suite
99 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000100
Guido van Rossum692adf12001-10-30 03:03:03 +0000101- binascii.b2a_base64 no longer places an arbitrary restriction of 57
102 bytes on its input.
103
Tim Peters84362bc2001-10-19 17:55:30 +0000104Library
105
Tim Peters5ebfd362001-11-13 23:11:19 +0000106- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000107 convenience function.
108
Tim Peters75335872001-11-03 19:35:43 +0000109- Symbolic group names in regular expressions must be unique. For
110 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
111 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000112 Python 2.2 detects this error at regexp compilation time;
113 previously, the error went undetected, and results were
114 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
115 pattern.subn() methods have been rewritten in C. Also, an
116 experimental function/method finditer() has been added, which works
117 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000118
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000119- Tix exposes more commands through the classes DirSelectBox,
120 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
121 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
122 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
123
Tim Peters98791af2001-10-23 01:59:54 +0000124- Traceback objects are now scanned by cyclic garbage collection, so
125 cycles created by casual use of sys.exc_info() no longer cause
126 permanent memory leaks (provided garbage collection is enabled).
127
Guido van Rossum49192142001-10-24 20:51:44 +0000128- os.extsep -- a new variable needed by the RISCOS support. It is the
129 separator used by extensions, and is '.' on all platforms except
130 RISCOS, where it is '/'. There is no need to use this variable
131 unless you have a masochistic desire to port your code to RISCOS.
132
Barry Warsaw012852b2001-11-16 16:17:27 +0000133- mimetypes.py has optional support for non-standard, but commonly
134 found types. guess_type() and guess_extension() now accept an
135 optional `strict' flag, defaulting to true, which controls whether
136 recognize non-standard types or not. A few non-standard types we
137 know about have been added. Also, when run as a script, there are
138 new -l and -e options.
139
140- statcache is now deprecated.
141
142- email.Utils.formatdate() now produces the preferred RFC 2822 style
143 dates with numeric timezones (it used to produce obsolete dates
144 hard coded to "GMT" timezone). An optional `localtime' flag is
145 added to produce dates in the local timezone, with daylight savings
146 time properly taken into account.
147
148- In pickle and cPickle, instead of masking errors in load() by
149 transforming them into SystemError, we let the original exception
150 propagate out. Also, implement support for __safe_for_unpickling__
151 in pickle, as it already was supported in cPickle.
152
Tim Peters84362bc2001-10-19 17:55:30 +0000153Tools/Demos
154
155Build
156
Barry Warsaw012852b2001-11-16 16:17:27 +0000157- The dbm module is built using libdb1 if available. The bsddb module
158 is built with libdb3 if available.
159
160- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
161
Tim Peters84362bc2001-10-19 17:55:30 +0000162C API
163
Tim Peters1fc240e2001-10-26 05:06:50 +0000164- New function PySequence_Fast_GET_SIZE() returns the size of a non-
165 NULL result from PySequence_Fast(), more quickly than calling
166 PySequence_Size().
167
Barry Warsaw012852b2001-11-16 16:17:27 +0000168- New argument unpacking function PyArg_UnpackTuple() added.
169
170- New functions PyObject_CallFunctionObjArgs() and
171 PyObject_CallMethodObjArgs() have been added to make it more
172 convenient and efficient to call functions and methods from C.
173
174- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
175 possible that this will propagate errors it didn't before.
176
177- New function PyObject_CheckReadBuffer(), which returns true if its
178 argument supports the single-segment readable buffer interface.
179
Tim Peters84362bc2001-10-19 17:55:30 +0000180New platforms
181
Guido van Rossum86443212001-10-27 22:28:54 +0000182- We've finally confirmed that this release builds on HP-UX 11.00,
183 *with* threads, and passes the test suite.
184
Tim Peters7a33d8b2001-11-05 02:51:07 +0000185- Thanks to a series of patches from Michael Muller, Python may build
186 again under OS/2 Visual Age C++.
187
Guido van Rossum49192142001-10-24 20:51:44 +0000188- Updated RISCOS port by Dietmar Schwertberger.
189
Tim Peters84362bc2001-10-19 17:55:30 +0000190Tests
191
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000192- Added a test script for the curses module. It isn't run automatically;
193 regrtest.py must be run with '-u curses' to enable it.
194
Tim Peters84362bc2001-10-19 17:55:30 +0000195Windows
196
Barry Warsaw012852b2001-11-16 16:17:27 +0000197Mac
198
199- PythonScript has been moved to unsupported and is slated to be
200 removed completely in the next release.
201
202- It should now be possible to build applets that work on both OS9 and
203 OSX.
204
205- The core is now linked with CoreServices not Carbon; as a side
206 result, default 8bit encoding on OSX is now ASCII.
207
208- Python should now build on OSX 10.1.1
209
Tim Peters84362bc2001-10-19 17:55:30 +0000210
Tim Petersabf925f2001-09-28 21:53:42 +0000211What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000212Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000213===========================
214
215Type/class unification and new-style classes
216
Guido van Rossum687ae002001-10-15 22:03:32 +0000217- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000218 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000219 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000220 remains: the __dict__ of a new-style class is a read-only proxy; you
221 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000222 __defined__ attribute of new-style types no longer exists, for lack
223 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000224 future a __cache__ may be resurrected with a similar function, if I
225 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000226
Tim Peters1c9ca872001-10-04 06:43:12 +0000227- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
228 always returned None, even when there was a class docstring).
229
230- doctest now finds and runs docstrings attached to new-style classes,
231 class methods, static methods, and properties.
232
Guido van Rossum9074ef62001-10-16 21:34:49 +0000233Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000234
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000235- A very subtle syntactical pitfall in list comprehensions was fixed.
236 For example: [a+b for a in 'abc', for b in 'def']. The comma in
237 this example is a mistake. Previously, this would silently let 'a'
238 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
239 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
240 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
241 Note that [a for a in <singleton>] is a convoluted way to say
242 [<singleton>] anyway, so it's not like any expressiveness is lost.
243
Guido van Rossum9074ef62001-10-16 21:34:49 +0000244- getattr(obj, name, default) now only catches AttributeError, as
245 documented, rather than returning the default value for all
246 exceptions (which could mask bugs in a __getattr__ hook, for
247 example).
248
Fred Drakecb7a6b52001-10-22 18:41:51 +0000249- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000250 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000251 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000252 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000253
Guido van Rossum1c486092001-10-19 02:05:35 +0000254- unicode(obj) now behaves more like str(obj), accepting arbitrary
255 objects, and calling a __unicode__ method if it exists.
256 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000257 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000258
Barry Warsawf6fb1712001-10-19 05:35:40 +0000259- isinstance() now allows any object as the first argument and a
260 class, a type or something with a __bases__ tuple attribute for the
261 second argument. The second argument may also be a tuple of a
262 class, type, or something with __bases__, in which case isinstance()
263 will return true if the first argument is an instance of any of the
264 things contained in the second argument tuple. E.g.
265
266 isinstance(x, (A, B))
267
268 returns true if x is an instance of A or B.
269
Guido van Rossum9074ef62001-10-16 21:34:49 +0000270Extension modules
271
272- thread.start_new_thread() now returns the thread ID (previously None).
273
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000274- binascii has now two quopri support functions, a2b_qp and b2a_qp.
275
Guido van Rossumc524d952001-10-19 01:31:59 +0000276- readline now supports setting the startup_hook and the
277 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000278
Guido van Rossumc524d952001-10-19 01:31:59 +0000279- os and posix supports chroot(), setgroups() and unsetenv() where
280 available. The stat(), fstat(), statvfs() and fstatvfs() functions
281 now return "pseudo-sequences" -- the various fields can now be
282 accessed as attributes (e.g. os.stat("/").st_mtime) but for
283 backwards compatibility they also behave as a fixed-length sequence.
284 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000285 attributes.
286
287- time: localtime(), gmtime() and strptime() now return a
288 pseudo-sequence similar to the os.stat() return value, with
289 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000290
Guido van Rossum9074ef62001-10-16 21:34:49 +0000291- Decompression objects in the zlib module now accept an optional
292 second parameter to decompress() that specifies the maximum amount
293 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000294
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000295- optional SSL support in the socket module now exports OpenSSL
296 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
297 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000298 automatically seed its PRNG. Also, the keyfile and certfile
299 arguments to socket.ssl() are now optional.
300
301- posixmodule (and by extension, the os module on POSIX platforms) now
302 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000303
Guido van Rossum9074ef62001-10-16 21:34:49 +0000304Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000305
Tim Peters7402f792001-10-02 03:53:41 +0000306- doctest now excludes functions and classes not defined by the module
307 being tested, thanks to Tim Hochberg.
308
Fred Drakecb7a6b52001-10-22 18:41:51 +0000309- HotShot, a new profiler implemented using a C-based callback, has
310 been added. This substantially reduces the overhead of profiling,
311 but it is still quite preliminary. Support modules and
312 documentation will be added in upcoming releases (before 2.2 final).
313
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000314- profile now produces correct output in situations where an exception
315 raised in Python is cleared by C code (e.g. hasattr()). This used
316 to cause wrong output, including spurious claims of recursive
317 functions and attribution of time spent to the wrong function.
318
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000319 The code and documentation for the derived OldProfile and HotProfile
320 profiling classes was removed. The code hasn't worked for years (if
321 you tried to use them, they raised exceptions). OldProfile
322 intended to reproduce the behavior of the profiler Python used more
323 than 7 years ago, and isn't interesting anymore. HotProfile intended
324 to provide a faster profiler (but producing less information), and
325 that's a worthy goal we intend to meet via a different approach (but
326 without losing information).
327
Tim Peterscce092d2001-10-09 05:31:56 +0000328- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000329 a much better system-specific calibration constant. The constant can
330 now be specified in an instance constructor, or as a Profile class or
331 instance variable, instead of by editing profile.py's source code.
332 Calibration must still be done manually (see the docs for the profile
333 module).
334
335 Note that Profile.calibrate() must be overriden by subclasses.
336 Improving the accuracy required exploiting detailed knowledge of
337 profiler internals; the earlier method abstracted away the details
338 and measured a simplified model instead, but consequently computed
339 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000340
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000341- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000342 which indicates whether output is intended for the header 'Q'
343 encoding.
344
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000345- The SocketServer.ThreadingMixIn class now closes the request after
346 finish_request() returns. (Not when it errors out though.)
347
Barry Warsawf6fb1712001-10-19 05:35:40 +0000348- The nntplib module's NNTP.body() method has grown a `file' argument
349 to allow saving the message body to a file.
350
351- The email package has added a class email.Parser.HeaderParser which
352 only parses headers and does not recurse into the message's body.
353 Also, the module/class MIMEAudio has been added for representing
354 audio data (contributed by Anthony Baxter).
355
356- ftplib should be able to handle files > 2GB.
357
358- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
359 ON, and OFF.
360
Fred Drakecb7a6b52001-10-22 18:41:51 +0000361- xml.dom.minidom NodeList objects now support the length attribute
362 and item() method as required by the DOM specifications.
363
Guido van Rossumed554f62001-10-02 23:15:37 +0000364Tools/Demos
365
366- Demo/dns was removed. It no longer serves any purpose; a package
367 derived from it is now maintained by Anthony Baxter, see
368 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000369
Barry Warsawf6fb1712001-10-19 05:35:40 +0000370- The freeze tool has been made more robust, and two new options have
371 been added: -X and -E.
372
Tim Petersabf925f2001-09-28 21:53:42 +0000373Build
374
Barry Warsawf6fb1712001-10-19 05:35:40 +0000375- configure will use CXX in LINKCC if CXX is used to build main() and
376 the system requires to link a C++ main using the C++ compiler.
377
Tim Petersabf925f2001-09-28 21:53:42 +0000378C API
379
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000380- The documentation for the tp_compare slot is updated to require that
381 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
382 not correct. This is not yet enforced but will be enforced in
383 Python 2.3; even later, we may use -2 to indicate errors and +2 for
384 "NotImplemented". Right now, -1 should be used for an error return.
385
Tim Petersd38b1c72001-09-30 05:09:37 +0000386- PyLong_AsLongLong() now accepts int (as well as long) arguments.
387 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
388 as long) arguments.
389
Guido van Rossum3c288632001-10-16 21:13:49 +0000390- PyThread_start_new_thread() now returns a long int giving the thread
391 ID, if one can be calculated; it returns -1 for error, 0 if no
392 thread ID is calculated (this is an incompatible change, but only
393 the thread module used this API). This code has only really been
394 tested on Linux and Windows; other platforms please beware (and
395 report any bugs or strange behavior).
396
Guido van Rossum1c486092001-10-19 02:05:35 +0000397- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
398 input.
399
Tim Petersabf925f2001-09-28 21:53:42 +0000400New platforms
401
402Tests
403
404Windows
405
Tim Peters04cf1d32001-10-09 22:39:40 +0000406- Installer: If you install IDLE, and don't disable file-extension
407 registration, a new "Edit with IDLE" context (right-click) menu entry
408 is created for .py and .pyw files.
409
Tim Peters1ce3cf72001-10-01 17:58:40 +0000410- The signal module now supports SIGBREAK on Windows, thanks to Steven
411 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
412 action remains to call Win32 ExitProcess(). This can be changed via
413 signal.signal(). For example:
414
415 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
416 # (SIGINT) behavior.
417 import signal
418 signal.signal(signal.SIGBREAK,
419 signal.default_int_handler)
420
421 try:
422 while 1:
423 pass
424 except KeyboardInterrupt:
425 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
426 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
427 # program without the possibility for any Python-level cleanup).
428 print "Clean exit"
429
Tim Petersabf925f2001-09-28 21:53:42 +0000430
Tim Petersb07352e2001-09-08 01:25:47 +0000431What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000432Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000433===========================
434
Guido van Rossum808eea72001-09-25 04:15:41 +0000435Type/class unification and new-style classes
436
437- pydoc and inspect are now aware of new-style classes;
438 e.g. help(list) at the interactive prompt now shows proper
439 documentation for all operations on list objects.
440
441- Applications using Jim Fulton's ExtensionClass module can now safely
442 be used with Python 2.2. In particular, Zope 2.4.1 now works with
443 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
444 examples also work again. It is hoped that Gtk and Boost also work
445 with 2.2a4 and beyond. (If you can confirm this, please write
446 webmaster@python.org; if there are still problems, please open a bug
447 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000448
Tim Peters66c1a522001-09-24 21:17:50 +0000449- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
450 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
451 in the constructed property object. fget, fset and fdel weren't
452 discoverable from Python in 2.2a3. __doc__ is new, and allows to
453 associate a docstring with a property.
454
Guido van Rossum808eea72001-09-25 04:15:41 +0000455- Comparison overloading is now more completely implemented. For
456 example, a str subclass instance can properly be compared to a str
457 instance, and it can properly overload comparison. Ditto for most
458 other built-in object types.
459
460- The repr() of new-style classes has changed; instead of <type
461 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
462 *except* for built-in types, which are still rendered as <type
463 'Foo'> (to avoid upsetting existing code that might parse or
464 otherwise rely on repr() of certain type objects).
465
466- The repr() of new-style objects is now always <Foo object at XXX>;
467 previously, it was sometimes <Foo instance at XXX>.
468
469- For new-style classes, what was previously called __getattr__ is now
470 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000471 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000472 one in classic classes is defined which is called only if regular
473 attribute access raises AttributeError; to catch *all* attribute
474 access, you can use __getattribute__ (for new-style classes). If
475 both are defined, __getattribute__ is called first, and if it raises
476 AttributeError, __getattr__ is called.
477
478- The __class__ attribute of new-style objects can be assigned to.
479 The new class must have the same C-level object layout as the old
480 class.
481
482- The builtin file type can be subclassed now. In the usual pattern,
483 "file" is the name of the builtin type, and file() is a new builtin
484 constructor, with the same signature as the builtin open() function.
485 file() is now the preferred way to open a file.
486
487- Previously, __new__ would only see sequential arguments passed to
488 the type in a constructor call; __init__ would see both sequential
489 and keyword arguments. This made no sense whatsoever any more, so
490 now both __new__ and __init__ see all arguments.
491
492- Previously, hash() applied to an instance of a subclass of str or
493 unicode always returned 0. This has been repaired.
494
495- Previously, an operation on an instance of a subclass of an
496 immutable type (int, long, float, complex, tuple, str, unicode),
497 where the subtype didn't override the operation (and so the
498 operation was handled by the builtin type), could return that
499 instance instead a value of the base type. For example, if s was of
500 a str sublass type, s[:] returned s as-is. Now it returns a str
501 with the same value as s.
502
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000503- Provisional support for pickling new-style objects has been added.
504
Guido van Rossum808eea72001-09-25 04:15:41 +0000505Core
506
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000507- file.writelines() now accepts any iterable object producing strings.
508
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000509- PyUnicode_FromEncodedObject() now works very much like
510 PyObject_Str(obj) in that it tries to use __str__/tp_str
511 on the object if the object is not a string or buffer. This
512 makes unicode() behave like str() when applied to non-string/buffer
513 objects.
514
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000515- PyFile_WriteObject now passes Unicode objects to the file's write
516 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000517 of a print statement must support Unicode objects, i.e. they must
518 at least convert them into ASCII strings.
519
Guido van Rossum624c8af2001-09-18 15:21:04 +0000520- Thread scheduling on Solaris should be improved; it is no longer
521 necessary to insert a small sleep at the start of a thread in order
522 to let other runnable threads be scheduled.
523
Tim Petersb07352e2001-09-08 01:25:47 +0000524Library
525
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000526- StringIO.StringIO instances and cStringIO.StringIO instances support
527 read character buffer compatible objects for their .write() methods.
528 These objects are converted to strings and then handled as such
529 by the instances.
530
Barry Warsaw2f600732001-09-24 04:28:10 +0000531- The "email" package has been added. This is basically a port of the
532 mimelib package <http://sf.net/projects/mimelib> with API changes
533 and some implementations updated to use iterators and generators.
534
Tim Peters8a9c2842001-09-22 21:30:22 +0000535- difflib.ndiff() and difflib.Differ.compare() are generators now. This
536 restores the ability of Tools/scripts/ndiff.py to start producing output
537 before the entire comparison is complete.
538
Barry Warsaw58b072d2001-09-22 04:44:21 +0000539- StringIO.StringIO instances and cStringIO.StringIO instances support
540 iteration just like file objects (i.e. their .readline() method is
541 called for each iteration until it returns an empty string).
542
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000543- The codecs module has grown four new helper APIs to access
544 builtin codecs: getencoder(), getdecoder(), getreader(),
545 getwriter().
546
Guido van Rossum624c8af2001-09-18 15:21:04 +0000547- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
548 simplifies writing XML RPC servers.
549
Barry Warsaw647d5e82001-09-28 17:01:02 +0000550- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000551 after interpretation of symbolic links. On non-Unix systems, this
552 is an alias for os.path.abspath().
553
Tim Peters16a77ad2001-09-08 04:00:12 +0000554- operator.indexOf() (PySequence_Index() in the C API) now works with any
555 iterable object.
556
Guido van Rossum624c8af2001-09-18 15:21:04 +0000557- smtplib now supports various authentication and security features of
558 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000559
Guido van Rossum624c8af2001-09-18 15:21:04 +0000560- hmac: a new module implementing keyed hashing for message
561 authentication.
562
563- mimetypes now recognizes more extensions and file types. At the
564 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000565
Guido van Rossum624c8af2001-09-18 15:21:04 +0000566- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000567 Python 2.2 bytecode generation. It has also been promoted from a
568 Tool to a standard library package. (Tools/compiler still exists as
569 a sample driver.)
570
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000571Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000572
Tim Petersb07352e2001-09-08 01:25:47 +0000573Build
574
Guido van Rossum624c8af2001-09-18 15:21:04 +0000575- Large file support (LFS) is now automatic when the platform supports
576 it; no more manual configuration tweaks are needed. On Linux, at
577 least, it's possible to have a system whose C library supports large
578 files but whose kernel doesn't; in this case, large file support is
579 still enabled but doesn't do you any good unless you upgrade your
580 kernel or share your Python executable with another system whose
581 kernel has large file support.
582
583- The configure script now supplies plausible defaults in a
584 cross-compilation environment. This doesn't mean that the supplied
585 values are always correct, or that cross-compilation now works
586 flawlessly -- but it's a first step (and it shuts up most of
587 autoconf's warnings about AC_TRY_RUN).
588
589- The Unix build is now a bit less chatty, courtesy of the parser
590 generator. The build is completely silent (except for errors) when
591 using "make -s", thanks to a -q option to setup.py.
592
Tim Petersb07352e2001-09-08 01:25:47 +0000593C API
594
Guido van Rossum624c8af2001-09-18 15:21:04 +0000595- The "structmember" API now supports some new flag bits to deny read
596 and/or write access to attributes in restricted execution mode.
597
Tim Petersb07352e2001-09-08 01:25:47 +0000598New platforms
599
Guido van Rossum624c8af2001-09-18 15:21:04 +0000600- Compaq's iPAQ handheld, running the "familiar" Linux distribution
601 (http://familiar.handhelds.org).
602
Tim Petersb07352e2001-09-08 01:25:47 +0000603Tests
604
Tim Peters8a9c2842001-09-22 21:30:22 +0000605- The "classic" standard tests, which work by comparing stdout to
606 an expected-output file under Lib/test/output/, no longer stop at
607 the first mismatch. Instead the test is run to completion, and a
608 variant of ndiff-style comparison is used to report all differences.
609 This is much easier to understand than the previous style of reporting.
610
611- The unittest-based standard tests now use regrtest's test_main()
612 convention, instead of running as a side-effect of merely being
613 imported. This allows these tests to be run in more natural and
614 flexible ways as unittests, outside the regrtest framework.
615
616- regrtest.py is much better integrated with unittest and doctest now,
617 especially in regard to reporting errors.
618
Tim Petersb07352e2001-09-08 01:25:47 +0000619Windows
620
Guido van Rossum624c8af2001-09-18 15:21:04 +0000621- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000622 that support it (NTFS under Windows 2000). See "What's New in
623 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000624
Tim Petersb07352e2001-09-08 01:25:47 +0000625
Tim Petersedc99312001-08-22 21:36:50 +0000626What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000627Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000628===========================
629
630Core
631
Tim Peters9fffa3e2001-09-04 05:14:19 +0000632- Conversion of long to float now raises OverflowError if the long is too
633 big to represent as a C double.
634
Tim Peters32f453e2001-09-03 08:35:41 +0000635- The 3-argument builtin pow() no longer allows a third non-None argument
636 if either of the first two arguments is a float, or if both are of
637 integer types and the second argument is negative (in which latter case
638 the arguments are converted to float, so this is really the same
639 restriction).
640
Tim Peters5d2b77c2001-09-03 05:47:38 +0000641- The builtin dir() now returns more information, and sometimes much
642 more, generally naming all attributes of an object, and all attributes
643 reachable from the object via its class, and from its class's base
644 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
645 an empty list. In 2.2a3,
646
647 >>> dir([])
648 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
649 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
650 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
651 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
652 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
653 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
654 'reverse', 'sort']
655
656 dir(module) continues to return only the module's attributes, though.
657
Tim Petersbdee63f2001-09-02 03:40:59 +0000658- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000659 than raising OverflowError. This is a partial implementation of PEP
660 237. You can use -Wdefault::OverflowWarning to enable a warning for
661 this situation, and -Werror::OverflowWarning to revert to the old
662 OverflowError exception.
663
Guido van Rossum61c345f2001-09-04 03:26:15 +0000664- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000665 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000666 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
667 -Qold, meaning the / operator has its classic meaning and no
668 warnings are issued. Using -Qwarn issues a run-time warning about
669 all uses of classic division for int and long arguments; -Qwarnall
670 also warns about classic division for float and complex arguments
671 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
672 new division by default, but only in the __main__ module. You can
673 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
674 __main__ module new division, and warns about classic division
675 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000676
Tim Petersbdee63f2001-09-02 03:40:59 +0000677- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000678 long, float, str, unicode, and tuple. (The types complex, list and
679 dictionary can also be subclassed; this was introduced earlier.)
680 Note that restrictions apply when subclassing immutable built-in
681 types: you can only affect the value of the instance by overloading
682 __new__. You can add mutable attributes, and the subclass instances
683 will have a __dict__ attribute, but you cannot change the "value"
684 (as implemented by the base class) of an immutable subclass instance
685 once it is created.
686
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000687- The dictionary constructor now takes an optional argument, a
688 mapping-like object, and initializes the dictionary from its
689 (key, value) pairs.
690
Tim Petersbdee63f2001-09-02 03:40:59 +0000691- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000692 "cooperative super calls" in a multiple inheritance setting. For an
693 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
694
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000695- A new built-in type, property, has been added. This enables the
696 creation of "properties". These are attributes implemented by
697 getter and setter functions (or only one of these for read-only or
698 write-only attributes), without the need to override __getattr__.
699 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000700
Tim Petersbdee63f2001-09-02 03:40:59 +0000701- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000702 liberalized, to allow leading zeroes. Examples of literals now
703 legal that were SyntaxErrors before:
704
705 00.0 0e3 0100j 07.5 00000000000000000008.
706
Tim Petersbdee63f2001-09-02 03:40:59 +0000707- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000708 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
709
Tim Petersedc99312001-08-22 21:36:50 +0000710Library
711
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000712- telnetlib includes symbolic names for the options, and support for
713 setting an option negotiation callback.
714
Tim Petersa40c7932001-09-05 22:36:56 +0000715- The new C standard no longer requires that math libraries set errno to
716 ERANGE on overflow. For platform libraries that exploit this new
717 freedom, Python's overflow-checking was wholly broken. A new overflow-
718 checking scheme attempts to repair that, but may not be reliable on all
719 platforms (C doesn't seem to provide anything both useful and portable
720 in this area anymore).
721
Martin v. Löwis44f86962001-09-05 13:44:54 +0000722- Asynchronous timeout actions are available through the new class
723 threading.Timer.
724
Tim Peters78526162001-09-05 00:53:45 +0000725- math.log and math.log10 now return sensible results for even huge
726 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
727
Tim Petersbdee63f2001-09-02 03:40:59 +0000728- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000729 currently held. See the docs for the imp module.
730
Tim Petersbdee63f2001-09-02 03:40:59 +0000731- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000732 dumps containing ints written on platforms where Python ints are 8 bytes.
733 When read on a box where Python ints are 4 bytes, such values are
734 converted to Python longs.
735
Tim Petersbdee63f2001-09-02 03:40:59 +0000736- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000737 code objects is no longer allowed. This plugs a security hole.
738
Steve Purcell6091cd62001-09-06 16:05:17 +0000739- unittest.TestResult instances no longer store references to tracebacks
740 generated by test failures. This prevents unexpected dangling references
741 to objects that should be garbage collected between tests.
742
Tim Petersedc99312001-08-22 21:36:50 +0000743Tools
744
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000745- Tools/scripts/fixdiv.py has been added which can be used to fix
746 division operators as per PEP 238.
747
Tim Petersedc99312001-08-22 21:36:50 +0000748Build
749
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000750- If you are an adventurous person using Mac OS X you may want to look at
751 Mac/OSX. There is a Makefile there that will build Python as a real Mac
752 application, which can be used for experimenting with Carbon or Cocoa.
753 Discussion of this on pythonmac-sig, please.
754
Tim Peters7eea37e2001-09-04 22:08:56 +0000755C API
756
757- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000758
Tim Peters9fffa3e2001-09-04 05:14:19 +0000759- Note that PyLong_AsDouble can fail! This has always been true, but no
760 callers checked for it. It's more likely to fail now, because overflow
761 errors are properly detected now. The proper way to check:
762
763 double x = PyLong_AsDouble(some_long_object);
764 if (x == -1.0 && PyErr_Occurred()) {
765 /* The conversion failed. */
766 }
767
Tim Petersbdee63f2001-09-02 03:40:59 +0000768- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000769 compile but will not participate in GC. To upgrade an extension
770 module:
771
772 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000773
Neil Schemenauer4042c692001-08-30 15:38:01 +0000774 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
775 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000776
Neil Schemenauer4042c692001-08-30 15:38:01 +0000777 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
778 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000779
Neil Schemenauer4042c692001-08-30 15:38:01 +0000780 - remove PyGC_HEAD_SIZE from object size calculations
781
782 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
783
Tim Petersbdee63f2001-09-02 03:40:59 +0000784- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000785 These can be used safely to construct string objects from a
786 sprintf-style format string (similar to the format string supported
787 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000788
Tim Petersedc99312001-08-22 21:36:50 +0000789New platforms
790
Tim Petersb7da0902001-09-02 23:01:43 +0000791- Stephen Hansen contributed patches sufficient to get a clean compile
792 under Borland C (Windows), but he reports problems running it and ran
793 out of time to complete the port. Volunteers? Expect a MemoryError
794 when importing the types module; this is probably shallow, and
795 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000796
Tim Petersedc99312001-08-22 21:36:50 +0000797Tests
798
799Windows
800
Tim Peters6e13a562001-09-06 00:32:15 +0000801- Large file support is now enabled on Win32 platforms as well as on
802 Win64. This means that, for example, you can use f.tell() and f.seek()
803 to manipulate files larger than 2 gigabytes (provided you have enough
804 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000805 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
806 filesize limit, and large file support makes no difference there.
807 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
808 NTFS has no practical limit on file size, and files of any size can be
809 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000810
Tim Petersbdee63f2001-09-02 03:40:59 +0000811- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000812 points to command.com (patch from Brian Quinlan).
813
Tim Petersedc99312001-08-22 21:36:50 +0000814
Tim Peters20f51a72001-07-21 02:31:40 +0000815What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000816Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000817===========================
818
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000819Build
820
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000821- Tim Peters developed a brand new Windows installer using Wise 8.1,
822 generously donated to us by Wise Solutions.
823
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000824- configure supports a new option --enable-unicode, with the values
825 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
826 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000827
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000828- A new configure option --enable-framework builds a Mac OS X framework,
829 which "make frameworkinstall" will install. This provides a starting
830 point for more mac-like functionality, join pythonmac-sig@python.org
831 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000832
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000833- The NeXT platform is no longer supported.
834
835- The `new' module is now statically linked.
836
Tim Peters0afb6092001-08-15 06:06:44 +0000837Tools
838
839- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000840 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000841 the module docstring for details.
842
Tim Peters20f51a72001-07-21 02:31:40 +0000843Tests
844
Tim Peters5e824c32001-08-12 22:25:01 +0000845- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000846 platforms, allowing to give clearer test result output. regrtest
847 also has optional --use/-u switch to run normally disabled tests
848 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000849
Tim Peters20f51a72001-07-21 02:31:40 +0000850- Several new tests in the standard test suite, with special thanks to
851 Nick Mathewson.
852
853Core
854
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000855- The floor division operator // has been added as outlined in PEP
856 238. The / operator still provides classic division (and will until
857 Python 3.0) unless "from __future__ import division" is included, in
858 which case the / operator will provide true division. The operator
859 module provides truediv() and floordiv() functions. Augmented
860 assignment variants are included, as are the equivalent overloadable
861 methods and C API methods. See the PEP for a full discussion:
862 <http://python.sf.net/peps/pep-0238.html>
863
Tim Peters6cd6a822001-08-17 22:11:27 +0000864- Future statements are now effective in simulated interactive shells
865 (like IDLE). This should "just work" by magic, but read Michael
866 Hudson's "Future statements in simulated shells" PEP 264 for full
867 details: <http://python.sf.net/peps/pep-0264.html>.
868
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000869- The type/class unification (PEP 252-253) was integrated into the
870 trunk and is not so tentative any more (the exact specification of
871 some features is still tentative). A lot of work has done on fixing
872 bugs and adding robustness and features (performance still has to
873 come a long way).
874
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000875- Warnings about a mismatch in the Python API during extension import
876 now use the Python warning framework (which makes it possible to
877 write filters for these warnings).
878
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000879- A function's __dict__ (aka func_dict) will now always be a
880 dictionary. It used to be possible to delete it or set it to None,
881 but now both actions raise TypeErrors. It is still legal to set it
882 to a dictionary object. Getting func.__dict__ before any attributes
883 have been assigned now returns an empty dictionary instead of None.
884
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000885- A new command line option, -E, was added which disables the use of
886 all environment variables, or at least those that are specifically
887 significant to Python. Usually those have a name starting with
888 "PYTHON". This was used to fix a problem where the tests fail if
889 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
890 older distribution.
891
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000892Library
893
Tim Peters5e824c32001-08-12 22:25:01 +0000894- New class Differ and new functions ndiff() and restore() in difflib.py.
895 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000896 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000897
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000898- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
899 value using the minimal quoting required for the value; more
900 reliable than using xml.sax.saxutils.escape() for attribute values.
901
902- Readline completion support for cmd.Cmd was added.
903
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000904- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
905
906- Added function threading.BoundedSemaphore()
907
908- Added Ka-Ping Yee's cgitb.py module.
909
910- The `new' module now exposes the CO_xxx flags.
911
Martin v. Löwis560da622001-11-24 09:24:51 +0000912- The gc module offers the get_referents function.
913
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000914New platforms
915
916C API
917
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000918- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
919 which provide a cross-platform implementations for the
920 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
921 the standard sprintf() and vsprintf() C lib APIs, these versions
922 apply bounds checking on the used buffer which enhances protection
923 against buffer overruns.
924
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000925- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000926 and extensions using different Unicode widths is rendered next to
927 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000928 will result in an ImportError. Unicode extensions writers must make
929 sure to check the Unicode width compatibility in their extensions by
930 using at least one of the mangled Unicode APIs in the extension.
931
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000932- Two new flags METH_NOARGS and METH_O are available in method definition
933 tables to simplify implementation of methods with no arguments and a
934 single untyped argument. Calling such methods is more efficient than
935 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
936 deprecated.
937
Tim Petersc1731372001-08-04 08:12:36 +0000938Windows
939
940- "import module" now compiles module.pyw if it exists and nothing else
941 relevant is found.
942
Tim Peters20f51a72001-07-21 02:31:40 +0000943
Guido van Rossum55a78992001-07-17 17:22:32 +0000944What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000945Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000946===========================
947
948Core
Tim Petersa814db52001-05-14 07:05:58 +0000949
Tim Peters6d6c1a32001-08-02 04:15:00 +0000950- TENTATIVELY, a large amount of code implementing much of what's
951 described in PEP 252 (Making Types Look More Like Classes) and PEP
952 253 (Subtyping Built-in Types) was added. This will be released
953 with Python 2.2a1. Documentation will be provided separately
954 through http://www.python.org/2.2/. The purpose of releasing this
955 with Python 2.2a1 is to test backwards compatibility. It is
956 possible, though not likely, that a decision is made not to release
957 this code as part of 2.2 final, if any serious backwards
958 incompapatibilities are found during alpha testing that cannot be
959 repaired.
960
Guido van Rossum55a78992001-07-17 17:22:32 +0000961- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000962 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000963 more 'yield' statements. See PEP 255. Since this adds a new
964 keyword to the language, this feature must be enabled by including a
965 future statement: "from __future__ import generators" (see PEP 236).
966 Generators will become a standard feature in a future release
967 (probably 2.3). Without this future statement, 'yield' remains an
968 ordinary identifier, but a warning is issued each time it is used.
969 (These warnings currently don't conform to the warnings framework of
970 PEP 230; we intend to fix this in 2.2a2.)
971
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000972- The UTF-16 codec was modified to be more RFC compliant. It will now
973 only remove BOM characters at the start of the string and then
974 only if running in native mode (UTF-16-LE and -BE won't remove a
975 leading BMO character).
976
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000977- Strings now have a new method .decode() to complement the already
978 existing .encode() method. These two methods provide direct access
979 to the corresponding decoders and encoders of the registered codecs.
980
981 To enhance the usability of the .encode() method, the special
982 casing of Unicode object return values was dropped (Unicode objects
983 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000984
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000985 Both methods will now return whatever the codec in charge of the
986 requested encoding returns as object, e.g. Unicode codecs will
987 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
988 will return u"äöü"). This enables codec writer to create codecs
989 for various simple to use conversions.
990
991 New codecs were added to demonstrate these new features (the .encode()
992 and .decode() columns indicate the type of the returned objects):
993
994 Name | .encode() | .decode() | Description
995 ----------------------------------------------------------------------
996 uu | string | string | UU codec (e.g. for email)
997 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000998 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000999 zlib | string | string | zlib compression
1000 hex | string | string | 2-byte hex codec
1001 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1002
Mark Hammond2a0af792001-05-14 03:09:36 +00001003- Some operating systems now support the concept of a default Unicode
1004 encoding for file system operations. Notably, Windows supports 'mbcs'
1005 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001006 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001007 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001008
1009 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001010 functions that return filenames (such as os.listdir()) to return Python
1011 string objects pre-encoded using the default file system encoding for
1012 the platform. As this encoding is likely to be different from Python's
1013 default encoding, converting this name to a Unicode object before passing
1014 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001015 would attempt to use its default encoding (generally ASCII) rather than
1016 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001017
Tim Petersa814db52001-05-14 07:05:58 +00001018 In general, this change simply removes surprises when working with
1019 Unicode and the file system, making these operations work as you expect,
1020 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001021 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001022
Tim Peters61dff2b2001-05-08 15:43:37 +00001023- Float (and complex) literals in source code were evaluated to full
1024 precision only when running from a .py file; the same code loaded from a
1025 .pyc (or .pyo) file could suffer numeric differences starting at about the
1026 12th significant decimal digit. For example, on a machine with IEEE-754
1027 floating arithmetic,
1028
1029 x = 9007199254740992.0
1030 print long(x)
1031
1032 printed 9007199254740992 if run directly from .py, but 9007199254740000
1033 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1034 str(float) instead of repr(float) when building code objects. marshal
1035 now uses repr(float) instead, which should reproduce floats to full
1036 machine precision (assuming the platform C float<->string I/O conversion
1037 functions are of good quality).
1038
1039 This may cause floating-point results to change in some cases, and
1040 usually for the better, but may also cause numerically unstable
1041 algorithms to break.
1042
Tim Peters2f228e72001-05-13 00:19:31 +00001043- The implementation of dicts suffers fewer collisions, which has speed
1044 benefits. However, the order in which dict entries appear in dict.keys(),
1045 dict.values() and dict.items() may differ from previous releases for a
1046 given dict. Nothing is defined about this order, so no program should
1047 rely on it. Nevertheless, it's easy to write test cases that rely on the
1048 order by accident, typically because of printing the str() or repr() of a
1049 dict to an "expected results" file. See Lib/test/test_support.py's new
1050 sortdict(dict) function for a simple way to display a dict in sorted
1051 order.
1052
Tim Peters7a3bfc32001-06-12 01:22:22 +00001053- Many other small changes to dicts were made, resulting in faster
1054 operation along the most common code paths.
1055
Guido van Rossum10315822001-05-01 20:54:30 +00001056- Dictionary objects now support the "in" operator: "x in dict" means
1057 the same as dict.has_key(x).
1058
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001059- The update() method of dictionaries now accepts generic mapping
1060 objects. Specifically the argument object must support the .keys()
1061 and __getitem__() methods. This allows you to say, for example,
1062 {}.update(UserDict())
1063
Guido van Rossum10315822001-05-01 20:54:30 +00001064- Iterators were added; this is a generalized way of providing values
1065 to a for loop. See PEP 234. There's a new built-in function iter()
1066 to return an iterator. There's a new protocol to get the next value
1067 from an iterator using the next() method (in Python) or the
1068 tp_iternext slot (in C). There's a new protocol to get iterators
1069 using the __iter__() method (in Python) or the tp_iter slot (in C).
1070 Iterating (i.e. a for loop) over a dictionary generates its keys.
1071 Iterating over a file generates its lines.
1072
Tim Petersf553f892001-05-01 20:45:31 +00001073- The following functions were generalized to work nicely with iterator
1074 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001075 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001076 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1077 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001078 join() method of strings
1079 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001080 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1081 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001082 right-hand side of assignment statements with multiple targets, such as
1083 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001084
Tim Petersd85e1022001-05-11 21:51:48 +00001085- Accessing module attributes is significantly faster (for example,
1086 random.random or os.path or yourPythonModule.yourAttribute).
1087
Tim Peterse63415e2001-05-08 04:38:29 +00001088- Comparing dictionary objects via == and != is faster, and now works even
1089 if the keys and values don't support comparisons other than ==.
1090
Tim Peters95bf9392001-05-10 08:32:44 +00001091- Comparing dictionaries in ways other than == and != is slower: there were
1092 insecurities in the dict comparison implementation that could cause Python
1093 to crash if the element comparison routines for the dict keys and/or
1094 values mutated the dicts. Making the code bulletproof slowed it down.
1095
Tim Peterseb28ef22001-06-02 05:27:19 +00001096- Collisions in dicts are resolved via a new approach, which can help
1097 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001098 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001099 faster now. Thanks to Christian Tismer for pointing out the cause and
1100 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001101
Tim Peters52e155e2001-06-16 05:42:57 +00001102- repr() is much faster for large containers (dict, list, tuple).
1103
1104
Tim Petersa814db52001-05-14 07:05:58 +00001105Library
1106
Fred Drake960fdf92001-07-20 18:38:26 +00001107- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1108 were added to the string module. These a locale-indenpendent
1109 constants, unlike letters, lowercase, and uppercase. These are now
1110 use in appropriate locations in the standard library.
1111
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001112- The flags used in dlopen calls can now be configured using
1113 sys.setdlopenflags and queried using sys.getdlopenflags.
1114
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001115- Fredrik Lundh's xmlrpclib is now a standard library module. This
1116 provides full client-side XML-RPC support. In addition,
1117 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1118 one asyncore-based). Thanks to Eric Raymond for the documentation.
1119
Guido van Rossum643d3912001-07-05 14:46:25 +00001120- The xrange() object is simplified: it no longer supports slicing,
1121 repetition, comparisons, efficient 'in' checking, the tolist()
1122 method, or the start, stop and step attributes. See PEP 260.
1123
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001124- A new function fnmatch.filter to filter lists of file names was added.
1125
Barry Warsawffd674d2001-05-22 16:00:10 +00001126- calendar.py uses month and day names based on the current locale.
1127
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001128- strop is now *really* obsolete (this was announced before with 1.6),
1129 and issues DeprecationWarning when used (except for the four items
1130 that are still imported into string.py).
1131
Tim Petersa814db52001-05-14 07:05:58 +00001132- Cookie.py now sorts key+value pairs by key in output strings.
1133
1134- pprint.isrecursive(object) didn't correctly identify recursive objects.
1135 Now it does.
1136
Tim Peters95b3f782001-05-14 18:39:41 +00001137- pprint functions now much faster for large containers (tuple, list, dict).
1138
Tim Peters7b9542a2001-06-10 23:40:19 +00001139- New 'q' and 'Q' format codes in the struct module, corresponding to C
1140 types "long long" and "unsigned long long" (on Windows, __int64). In
1141 native mode, these can be used only when the platform C compiler supports
1142 these types (when HAVE_LONG_LONG is #define'd by the Python config
1143 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001144 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1145 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001146
Guido van Rossum83213cc2001-06-12 16:48:52 +00001147- The site module installs a new built-in function 'help' that invokes
1148 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1149 it displays a message reminding the user to use 'help()' or
1150 'help(object)'.
1151
Tim Petersa814db52001-05-14 07:05:58 +00001152Tests
1153
1154- New test_mutants.py runs dict comparisons where the key and value
1155 comparison operators mutute the dicts randomly during comparison. This
1156 rapidly causes Python to crash under earlier releases (not for the faint
1157 of heart: it can also cause Win9x to freeze or reboot!).
1158
1159- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001160 pprint.isreadable() return sensible results. Also verifies that simple
1161 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001162
Tim Peters4324aa32001-05-28 22:30:08 +00001163C API
1164
1165- Removed the unused last_is_sticky argument from the internal
1166 _PyTuple_Resize(). If this affects you, you were cheating.
1167
1168
Guido van Rossum55a78992001-07-17 17:22:32 +00001169======================================================================
1170
1171
Guido van Rossumffe13be2001-04-16 18:46:45 +00001172What's New in Python 2.1 (final)?
1173=================================
1174
1175We only changed a few things since the last release candidate, all in
1176Python library code:
1177
1178- A bug in the locale module was fixed that affected locales which
1179 define no grouping for numeric formatting.
1180
1181- A few bugs in the weakref module's implementations of weak
1182 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1183 and the test suite was updated to check for these bugs.
1184
1185- An old bug in the os.path.walk() function (introduced in Python
1186 2.0!) was fixed: a non-existent file would cause an exception
1187 instead of being ignored.
1188
1189- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1190 PyChecker.
1191
1192
Guido van Rossum5b08f132001-04-16 02:05:23 +00001193What's New in Python 2.1c2?
1194===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001195
Guido van Rossum5b08f132001-04-16 02:05:23 +00001196A flurry of small changes, and one showstopper fixed in the nick of
1197time made it necessary to release another release candidate. The list
1198here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001199
Guido van Rossum5b08f132001-04-16 02:05:23 +00001200Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001201
Guido van Rossum5b08f132001-04-16 02:05:23 +00001202- Tim discovered a nasty bug in the dictionary code, caused by
1203 PyDict_Next() calling dict_resize(), and the GC code's use of
1204 PyDict_Next() violating an assumption in dict_items(). This was
1205 fixed with considerable amounts of band-aid, but the net effect is a
1206 saner and more robust implementation.
1207
1208- Made a bunch of symbols static that were accidentally global.
1209
1210Build and Ports
1211
1212- The setup.py script didn't check for a new enough version of zlib
1213 (1.1.3 is needed). Now it does.
1214
1215- Changed "make clean" target to also remove shared libraries.
1216
1217- Added a more general warning about the SGI Irix optimizer to README.
1218
1219Library
1220
1221- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1222 omitted the slash between host and file.html.
1223
1224- The mailbox module's _Mailbox class contained a completely broken
1225 and undocumented seek() method. Ripped it out.
1226
1227- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1228 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1229
1230- Fixed a few last-minute bugs in unittest.
1231
1232Extensions
1233
1234- Reverted the patch to the OpenSSL code in socketmodule.c to support
1235 RAND_status() and the EGD, and the subsequent patch that tried to
1236 fix it for pre-0.9.5 versions; the problem with the patch is that on
1237 some systems it issues a warning whenever socket is imported, and
1238 that's unacceptable.
1239
1240Tests
1241
1242- Fixed the pickle tests to work with "import test.test_pickle".
1243
1244- Tweaked test_locale.py to actually run the test Windows.
1245
1246- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1247 not "wb" (which is not a valid mode at all).
1248
1249- Fix pstats browser crashes. Import readline if it exists to make
1250 the user interface nicer.
1251
1252- Add "import thread" to the top of test modules that import the
1253 threading module (test_asynchat and test_threadedtempfile). This
1254 prevents test failures caused by a broken threading module resulting
1255 from a previously caught failed import.
1256
1257- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1258 needed on some platforms (e.g. Solaris 8) when the tests are run
1259 twice in succession.
1260
1261- Skip rather than fail test_sunaudiodev if no audio device is found.
1262
1263
1264What's New in Python 2.1c1?
1265===========================
1266
1267This list was significantly updated when 2.1c2 was released; the 2.1c1
1268release didn't mention most changes that were actually part of 2.1c1:
1269
1270Legal
1271
1272- Copyright was assigned to the Python Software Foundation (PSF) and a
1273 PSF license (very similar to the CNRI license) was added.
1274
1275- The CNRI copyright notice was updated to include 2001.
1276
1277Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001278
Guido van Rossumc9932722001-04-12 02:31:27 +00001279- After a public outcry, assignment to __debug__ is no longer illegal;
1280 instead, a warning is issued. It will become illegal in 2.2.
1281
Guido van Rossum5b08f132001-04-16 02:05:23 +00001282- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1283 "%#x" now always prepends "0x", even if the value is zero.
1284
1285- Fixed some nits in the bytecode compiler.
1286
1287- Fixed core dumps when calling certain kinds of non-functions.
1288
1289- Fixed various core dumps caused by reference count bugs.
1290
1291Build and Ports
1292
1293- Use INSTALL_SCRIPT to install script files.
1294
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001295- New port: SCO Unixware 7, by Billy G. Allie.
1296
Guido van Rossum5b08f132001-04-16 02:05:23 +00001297- Updated RISCOS port.
1298
1299- Updated BeOS port and notes.
1300
1301- Various other porting problems resolved.
1302
1303Library
1304
1305- The TERMIOS and SOCKET modules are now truly obsolete and
1306 unnecessary. Their symbols are incorporated in the termios and
1307 socket modules.
1308
1309- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1310 better tests for pickling.
1311
1312- threading: make Condition.wait() robust against KeyboardInterrupt.
1313
1314- zipfile: add support to zipfile to support opening an archive
1315 represented by an open file rather than a file name. Fix bug where
1316 the archive was not properly closed. Fixed a bug in this bugfix
1317 where flush() was called for a read-only file.
1318
1319- imputil: added an uninstall() method to the ImportManager.
1320
1321- Canvas: fixed bugs in lower() and tkraise() methods.
1322
1323- SocketServer: API change (added overridable close_request() method)
1324 so that the TCP server can explicitly close the request.
1325
1326- pstats: Eric Raymond added a simple interactive statistics browser,
1327 invoked when the module is run as a script.
1328
1329- locale: fixed a problem in format().
1330
1331- webbrowser: made it work when the BROWSER environment variable has a
1332 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1333 KDE 2. Fixed some other nits.
1334
1335- unittest: changes to allow using a different exception than
1336 AssertionError, and added a few more function aliases. Some other
1337 small changes.
1338
1339- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1340
1341- asynchat: fixed a critical bug in asynchat that slipped through the
1342 2.1b2 release. Fixed another rare bug.
1343
1344- Fix some unqualified except: clauses (always a bad code example).
1345
1346XML
1347
1348- pyexpat: new API get_version_string().
1349
1350- Fixed some minidom bugs.
1351
1352Extensions
1353
1354- Fixed a core dump in _weakref. Removed the weakref.mapping()
1355 function (it adds nothing to the API).
1356
1357- Rationalized the use of header files in the readline module, to make
1358 it compile (albeit with some warnings) with the very recent readline
1359 4.2, without breaking for earlier versions.
1360
1361- Hopefully fixed a buffering problem in linuxaudiodev.
1362
1363- Attempted a fix to make the OpenSSL support in the socket module
1364 work again with pre-0.9.5 versions of OpenSSL.
1365
1366Tests
1367
1368- Added a test case for asynchat and asyncore.
1369
1370- Removed coupling between tests where one test failing could break
1371 another.
1372
1373Tools
1374
1375- Ping added an interactive help browser to pydoc, fixed some nits
1376 in the rest of the pydoc code, and added some features to his
1377 inspect module.
1378
1379- An updated python-mode.el version 4.1 which integrates Ken
1380 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1381 much nicer in XEmacs and Emacs. When stepping through your program
1382 with pdb, in either the shell window or the *Python* window, the
1383 source file and line will be tracked by an arrow. Very cool!
1384
1385- IDLE: syntax warnings in interactive mode are changed into errors.
1386
1387- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001388 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001389
1390- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001391
Barry Warsaw11e89c72001-04-11 20:37:57 +00001392
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001393What's New in Python 2.1 beta 2?
1394================================
1395
Guido van Rossum053ae352001-03-22 14:17:21 +00001396(Unlisted are many fixed bugs, more documentation, etc.)
1397
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001398Core language, builtins, and interpreter
1399
Guido van Rossum053ae352001-03-22 14:17:21 +00001400- The nested scopes work (enabled by "from __future__ import
1401 nested_scopes") is completed; in particular, the future now extends
1402 into code executed through exec, eval() and execfile(), and into the
1403 interactive interpreter.
1404
1405- When calling a base class method (e.g. BaseClass.__init__(self)),
1406 this is now allowed even if self is not strictly spoken a class
1407 instance (e.g. when using metaclasses or the Don Beaudry hook).
1408
1409- Slice objects are now comparable but not hashable; this prevents
1410 dict[:] from being accepted but meaningless.
1411
1412- Complex division is now calculated using less braindead algorithms.
1413 This doesn't change semantics except it's more likely to give useful
1414 results in extreme cases. Complex repr() now uses full precision
1415 like float repr().
1416
1417- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1418
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001419- It is illegal to assign to the name __debug__, which is set when the
1420 interpreter starts. It is effectively a compile-time constant.
1421
1422- A warning will be issued if a global statement for a variable
1423 follows a use or assignment of that variable.
1424
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001425Standard library
1426
Guido van Rossum053ae352001-03-22 14:17:21 +00001427- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1428 inspired by JUnit), is now part of the standard library. You now
1429 have a choice of two testing frameworks: unittest requires you to
1430 write testcases as separate code, doctest gathers them from
1431 docstrings. Both approaches have their advantages and
1432 disadvantages.
1433
1434- A new module Tix was added, which wraps the Tix extension library
1435 for Tk. With that module, it is not necessary to statically link
1436 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1437 require" command. See Demo/tix/.
1438
1439- tzparse.py is now obsolete.
1440
1441- In gzip.py, the seek() and tell() methods are removed -- they were
1442 non-functional anyway, and it's better if callers can test for their
1443 existence with hasattr().
1444
1445Python/C API
1446
1447- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1448 that's already in the dictionary during a PyDict_Next() iteration.
1449 This used to fail occasionally when a dictionary resize operation
1450 could be triggered that would rehash all the keys. All other
1451 modifications to the dictionary are still off-limits during a
1452 PyDict_Next() iteration!
1453
1454- New extended APIs related to passing compiler variables around.
1455
1456- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1457 implement isinstance() and issubclass().
1458
1459- Py_BuildValue() now has a "D" conversion to create a Python complex
1460 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001461
Fred Drake4e262a92001-03-22 18:26:47 +00001462- Extensions types which support weak references must now set the
1463 field allocated for the weak reference machinery to NULL themselves;
1464 this is done to avoid the cost of checking each object for having a
1465 weakly referencable type in PyObject_INIT(), since most types are
1466 not weakly referencable.
1467
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001468- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1469 free variables and cell variables to and from the frame's f_locals.
1470
1471- Variants of several functions defined in pythonrun.h have been added
1472 to support the nested_scopes future statement. The variants all end
1473 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1474 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1475 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001476 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001477
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001478Distutils
1479
1480- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1481 into the release tree.
1482
Tim Peters0e57abf2001-05-02 07:39:38 +00001483- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001484 (an uninstaller, more customization of the installer's display)
1485
1486- from Jack Jansen: added Mac-specific code to generate a dialog for
1487 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001488 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001489 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001490
1491- added 'platforms' and 'keywords' to the set of metadata that can be
1492 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001493
1494- applied patches from Jason Tishler to make the compiler class work with
1495 Cygwin.
1496
1497
Tim Peters2fe289a2001-03-01 22:19:38 +00001498What's New in Python 2.1 beta 1?
1499================================
Tim Petersd66595f2001-02-04 03:09:53 +00001500
1501Core language, builtins, and interpreter
1502
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001503- Following an outcry from the community about the amount of code
1504 broken by the nested scopes feature introduced in 2.1a2, we decided
1505 to make this feature optional, and to wait until Python 2.2 (or at
1506 least 6 months) to make it standard. The option can be enabled on a
1507 per-module basis by adding "from __future__ import nested_scopes" at
1508 the beginning of a module (before any other statements, but after
1509 comments and an optional docstring). See PEP 236 (Back to the
1510 __future__) for a description of the __future__ statement. PEP 227
1511 (Statically Nested Scopes) has been updated to reflect this change,
1512 and to clarify the semantics in a number of endcases.
1513
1514- The nested scopes code, when enabled, has been hardened, and most
1515 bugs and memory leaks in it have been fixed.
1516
1517- Compile-time warnings are now generated for a number of conditions
1518 that will break or change in meaning when nested scopes are enabled:
1519
1520 - Using "from...import *" or "exec" without in-clause in a function
1521 scope that also defines a lambda or nested function with one or
1522 more free (non-local) variables. The presence of the import* or
1523 bare exec makes it impossible for the compiler to determine the
1524 exact set of local variables in the outer scope, which makes it
1525 impossible to determine the bindings for free variables in the
1526 inner scope. To avoid the warning about import *, change it into
1527 an import of explicitly name object, or move the import* statement
1528 to the global scope; to avoid the warning about bare exec, use
1529 exec...in... (a good idea anyway -- there's a possibility that
1530 bare exec will be deprecated in the future).
1531
1532 - Use of a global variable in a nested scope with the same name as a
1533 local variable in a surrounding scope. This will change in
1534 meaning with nested scopes: the name in the inner scope will
1535 reference the variable in the outer scope rather than the global
1536 of the same name. To avoid the warning, either rename the outer
1537 variable, or use a global statement in the inner function.
1538
Neil Schemenauera35c6882001-02-27 04:45:05 +00001539- An optional object allocator has been included. This allocator is
1540 optimized for Python objects and should be faster and use less memory
1541 than the standard system allocator. It is not enabled by default
1542 because of possible thread safety problems. The allocator is only
1543 protected by the Python interpreter lock and it is possible that some
1544 extension modules require a thread safe allocator. The object
1545 allocator can be enabled by providing the "--with-pymalloc" option to
1546 configure.
1547
Tim Petersd66595f2001-02-04 03:09:53 +00001548Standard library
1549
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001550- pyexpat now detects the expat version if expat.h defines it. A
1551 number of additional handlers are provided, which are only available
1552 since expat 1.95. In addition, the methods SetParamEntityParsing and
1553 GetInputContext of Parser objects are available with 1.95.x
1554 only. Parser objects now provide the ordered_attributes and
1555 specified_attributes attributes. A new module expat.model was added,
1556 which offers a number of additional constants if 1.95.x is used.
1557
1558- xml.dom offers the new functions registerDOMImplementation and
1559 getDOMImplementation.
1560
1561- xml.dom.minidom offers a toprettyxml method. A number of DOM
1562 conformance issues have been resolved. In particular, Element now
1563 has an hasAttributes method, and the handling of namespaces was
1564 improved.
1565
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001566- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1567 getting information about live Python code, and pydoc.py, a module
1568 for interactively converting docstrings to HTML or text.
1569 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001570 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001571 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1572 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001573
Tim Peters1eff7962001-03-01 02:31:33 +00001574- New library module difflib.py, primarily packaging the SequenceMatcher
1575 class at the heart of the popular ndiff.py file-comparison tool.
1576
1577- doctest.py (a framework for verifying Python code examples in docstrings)
1578 is now part of the std library.
1579
Tim Petersd66595f2001-02-04 03:09:53 +00001580Windows changes
1581
Guido van Rossume3955a82001-03-02 14:05:59 +00001582- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1583 small GUI that lets you browse the module docstrings using your
1584 default web browser.
1585
Tim Peters1eff7962001-03-01 02:31:33 +00001586- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1587 Platforms) is implemented. See
1588
1589 http://python.sourceforge.net/peps/pep-0235.html
1590
1591 for full details, especially the "Current Lower-Left Semantics" section.
1592 The new Windows import rules are simpler than before:
1593
1594 A. If the PYTHONCASEOK environment variable exists, same as
1595 before: silently accept the first case-insensitive match of any
1596 kind; raise ImportError if none found.
1597
1598 B. Else search sys.path for the first case-sensitive match; raise
1599 ImportError if none found.
1600
1601 The same rules have been implented on other platforms with case-
1602 insensitive but case-preserving filesystems too (including Cygwin, and
1603 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001604
Tim Peters25a9ce32001-02-19 07:06:36 +00001605- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1606 what it's supposed to do (and does do under NT and 2000) via direct
1607 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001608 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001609 all Win9x systems before.
1610
Tim Peters1eff7962001-03-01 02:31:33 +00001611- Build: Subproject _test (effectively) renamed to _testcapi.
1612
Tim Peters2fe289a2001-03-01 22:19:38 +00001613New platforms
1614
1615- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1616 Thanks to Steven Majewski!
1617
1618- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1619 Tishler!
1620
Guido van Rossum9089b272001-03-02 06:49:50 +00001621- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1622 Schwertberger! See RISCOS/README for more information -- it seems
1623 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001624 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001625
Tim Peters25a9ce32001-02-19 07:06:36 +00001626
Tim Petersd7b5e882001-01-25 03:36:26 +00001627What's New in Python 2.1 alpha 2?
1628=================================
Tim Peters40ead762001-01-27 05:35:26 +00001629
Tim Petersd7b5e882001-01-25 03:36:26 +00001630Core language, builtins, and interpreter
1631
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001632- Scopes nest. If a name is used in a function or class, but is not
1633 local, the definition in the nearest enclosing function scope will
1634 be used. One consequence of this change is that lambda statements
1635 could reference variables in the namespaces where the lambda is
1636 defined. In some unusual cases, this change will break code.
1637
1638 In all previous version of Python, names were resolved in exactly
1639 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001640 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001641 function A is defined within a function B, the names bound in B are
1642 not visible in A. The new rules make names bound in B visible in A,
1643 unless A contains a name binding that hides the binding in B.
1644
1645 Section 4.1 of the reference manual describes the new scoping rules
1646 in detail. The test script in Lib/test/test_scope.py demonstrates
1647 some of the effects of the change.
1648
1649 The new rules will cause existing code to break if it defines nested
1650 functions where an outer function has local variables with the same
1651 name as globals or builtins used by the inner function. Example:
1652
1653 def munge(str):
1654 def helper(x):
1655 return str(x)
1656 if type(str) != type(''):
1657 str = helper(str)
1658 return str.strip()
1659
1660 Under the old rules, the name str in helper() is bound to the
1661 builtin function str(). Under the new rules, it will be bound to
1662 the argument named str and an error will occur when helper() is
1663 called.
1664
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001665- The compiler will report a SyntaxError if "from ... import *" occurs
1666 in a function or class scope. The language reference has documented
1667 that this case is illegal, but the compiler never checked for it.
1668 The recent introduction of nested scope makes the meaning of this
1669 form of name binding ambiguous. In a future release, the compiler
1670 may allow this form when there is no possibility of ambiguity.
1671
Tim Peters40ead762001-01-27 05:35:26 +00001672- repr(string) is easier to read, now using hex escapes instead of octal,
1673 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1674
1675 >>> "\texample \r\n" + chr(0) + chr(255)
1676 '\texample \r\n\x00\xff' # in 2.1
1677 '\011example \015\012\000\377' # in 2.0
1678
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001679- Functions are now compared and hashed by identity, not by value, since
1680 the func_code attribute is writable.
1681
Fred Drakefb9d7122001-02-01 20:00:40 +00001682- Weak references (PEP 205) have been added. This involves a few
1683 changes in the core, an extension module (_weakref), and a Python
1684 module (weakref). The weakref module is the public interface. It
1685 includes support for "explicit" weak references, proxy objects, and
1686 mappings with weakly held values.
1687
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001688- A 'continue' statement can now appear in a try block within the body
1689 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001690 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001691
Tim Petersd7b5e882001-01-25 03:36:26 +00001692Standard library
1693
Barry Warsaw30dbd142001-01-31 22:14:01 +00001694- mailbox.py now has a new class, PortableUnixMailbox which is
1695 identical to UnixMailbox but uses a more portable scheme for
1696 determining From_ separators. Also, the constructors for all the
1697 classes in this module have a new optional `factory' argument, which
1698 is a callable used when new message classes must be instantiated by
1699 the next() method.
1700
Tim Petersd7b5e882001-01-25 03:36:26 +00001701- random.py is now self-contained, and offers all the functionality of
1702 the now-deprecated whrandom.py. See the docs for details. random.py
1703 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001704 and restoring the internal state of the generator; and jumpahead(n),
1705 for quickly forcing the internal state to be the same as if n calls to
1706 random() had been made. The latter is particularly useful for multi-
1707 threaded programs, creating one instance of the random.Random() class for
1708 each thread, then using .jumpahead() to force each instance to use a
1709 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001710
Tim Peters0de88fc2001-02-01 04:59:18 +00001711- random.py's seed() function is new. For bit-for-bit compatibility with
1712 prior releases, use the whseed function instead. The new seed function
1713 addresses two problems: (1) The old function couldn't produce more than
1714 about 2**24 distinct internal states; the new one about 2**45 (the best
1715 that can be done in the Wichmann-Hill generator). (2) The old function
1716 sometimes produced identical internal states when passed distinct
1717 integers, and there was no simple way to predict when that would happen;
1718 the new one guarantees to produce distinct internal states for all
1719 arguments in [0, 27814431486576L).
1720
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001721- The socket module now supports raw packets on Linux. The socket
1722 family is AF_PACKET.
1723
Tim Peters9ea17ac2001-02-02 05:57:15 +00001724- test_capi.py is a start at running tests of the Python C API. The tests
1725 are implemented by the new Modules/_testmodule.c.
1726
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001727- A new extension module, _symtable, provides provisional access to the
1728 internal symbol table used by the Python compiler. A higher-level
1729 interface will be added on top of _symtable in a future release.
1730
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001731- Removed the obsolete soundex module.
1732
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001733- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1734 the isSameNode method; NamedNodeMap the get method.
1735
1736- xml.sax.expatreader supports the lexical handler property; it
1737 generates comment, startCDATA, and endCDATA events.
1738
Tim Petersee826f82001-01-31 19:39:44 +00001739Windows changes
1740
1741- Build procedure: the zlib project is built in a different way that
1742 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001743 the zlib binary used. See PCbuild\readme.txt for details. Your old
1744 zlib-related directories can be deleted; you'll need to download fresh
1745 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001746
Tim Peters9ea17ac2001-02-02 05:57:15 +00001747- Build: New subproject _test for the benefit of test_capi.py (see above).
1748
Tim Petersb16c56f2001-02-02 21:24:51 +00001749- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1750 interface to some Python compiler internals).
1751
1752- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001753 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001754
Tim Petersa3a3a032000-11-30 05:22:44 +00001755What's New in Python 2.1 alpha 1?
1756=================================
1757
1758Core language, builtins, and interpreter
1759
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001760- There is a new Unicode companion to the PyObject_Str() API
1761 called PyObject_Unicode(). It behaves in the same way as the
1762 former, but assures that the returned value is an Unicode object
1763 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001764
Guido van Rossumf98eda02001-01-17 15:54:45 +00001765- The comparison operators support "rich comparison overloading" (PEP
1766 207). C extension types can provide a rich comparison function in
1767 the new tp_richcompare slot in the type object. The cmp() function
1768 and the C function PyObject_Compare() first try the new rich
1769 comparison operators before trying the old 3-way comparison. There
1770 is also a new C API PyObject_RichCompare() (which also falls back on
1771 the old 3-way comparison, but does not constrain the outcome of the
1772 rich comparison to a Boolean result).
1773
1774 The rich comparison function takes two objects (at least one of
1775 which is guaranteed to have the type that provided the function) and
1776 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1777 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1778 object, which may be NotImplemented (in which case the tp_compare
1779 slot function is used as a fallback, if defined).
1780
1781 Classes can overload individual comparison operators by defining one
1782 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001783 __ge__. There are no explicit "reflected argument" versions of
1784 these; instead, __lt__ and __gt__ are each other's reflection,
1785 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1786 reflection (similar at the C level). No other implications are
1787 made; in particular, Python does not assume that == is the Boolean
1788 inverse of !=, or that < is the Boolean inverse of >=. This makes
1789 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001790
1791 Classes or types that want to implement (in)equality tests but not
1792 the ordering operators (i.e. unordered types) should implement ==
1793 and !=, and raise an error for the ordering operators.
1794
Guido van Rossuma88479f2001-01-18 14:28:08 +00001795 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001796 Boolean; e.g. a matrix type might want to return a matrix of bits
1797 for A < B, giving elementwise comparisons. Such types should ensure
1798 that any interpretation of their value in a Boolean context raises
1799 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1800 at the C level) to always raise an exception.
1801
Guido van Rossuma88479f2001-01-18 14:28:08 +00001802- Complex numbers use rich comparisons to define == and != but raise
1803 an exception for <, <=, > and >=. Unfortunately, this also means
1804 that cmp() of two complex numbers raises an exception when the two
1805 numbers differ. Since it is not mathematically meaningful to compare
1806 complex numbers except for equality, I hope that this doesn't break
1807 too much code.
1808
Tim Peters3389f192001-02-18 08:48:49 +00001809- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001810 not defined by the language, other than that it's arbitrary but
1811 consistent (see the Reference Manual). An implementation detail changed
1812 in 2.1a1 such that None now compares less than any other object. Code
1813 relying on this new behavior (like code that relied on the previous
1814 behavior) does so at its own risk.
1815
Barry Warsaw573b5412001-01-15 20:43:18 +00001816- Functions and methods now support getting and setting arbitrarily
1817 named attributes (PEP 232). Functions have a new __dict__
1818 (a.k.a. func_dict) which hold the function attributes. Methods get
1819 and set attributes on their underlying im_func. It is a TypeError
1820 to set an attribute on a bound method.
1821
Guido van Rossum051e3352001-01-15 19:11:10 +00001822- The xrange() object implementation has been improved so that
1823 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1824 limitation that in this case len(xrange(sys.maxint)) can't be
1825 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1826 work fine as long as the index i doesn't actually reach 2**31.
1827 (Python uses regular ints for sequence and string indices; fixing
1828 that is much more work.)
1829
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001830- Two changes to from...import:
1831
Guido van Rossumba381232001-02-03 15:06:40 +00001832 1) "from M import X" now works even if (after loading module M)
1833 sys.modules['M'] is not a real module; it's basically a getattr()
1834 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001835
1836 2) "from M import *" now looks for M.__all__ to decide which names to
1837 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1838 filters out names starting with '_' as before. Whether or not
1839 __all__ exists, there's no restriction on the type of M.
1840
Guido van Rossumf61f1662001-01-10 20:13:55 +00001841- File objects have a new method, xreadlines(). This is the fastest
1842 way to iterate over all lines in a file:
1843
1844 for line in file.xreadlines():
1845 ...do something to line...
1846
1847 See the xreadlines module (mentioned below) for how to do this for
1848 other file-like objects.
1849
1850- Even if you don't use file.xreadlines(), you may expect a speedup on
1851 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001852 quite a bit in platform-specific ways: on systems (like Linux) that
1853 support flockfile(), getc_unlocked(), and funlockfile(), those are
1854 used by default. On systems (like Windows) without getc_unlocked(),
1855 a complicated (but still thread-safe) method using fgets() is used by
1856 default.
1857
Tim Petersd52269b2001-01-25 06:23:18 +00001858 You can force use of the fgets() method by #define'ing
1859 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001860 getc_unlocked()).
1861
Tim Petersd52269b2001-01-25 06:23:18 +00001862 You can force fgets() not to be used by #define'ing
1863 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001864 test_bufio.py fails -- and let us know if it does!).
1865
1866- In addition, the fileinput module, while still slower than the other
1867 methods on most platforms, has been sped up too, by using
1868 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001869
1870- Support for run-time warnings has been added, including a new
1871 command line option (-W) to specify the disposition of warnings.
1872 See the description of the warnings module below.
1873
1874- Extensive changes have been made to the coercion code. This mostly
1875 affects extension modules (which can now implement mixed-type
1876 numerical operators without having to use coercion), but
1877 occasionally, in boundary cases the coercion semantics have changed
1878 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001879 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001880 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001881 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001882
Guido van Rossumf98eda02001-01-17 15:54:45 +00001883- In connection with the coercion changes, a new built-in singleton
1884 object, NotImplemented is defined. This can be returned for
1885 operations that wish to indicate they are not implemented for a
1886 particular combination of arguments. From C, this is
1887 Py_NotImplemented.
1888
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001889- The interpreter accepts now bytecode files on the command line even
1890 if they do not have a .pyc or .pyo extension. On Linux, after executing
1891
Martin v. Löwise214baa2001-02-04 22:37:56 +00001892import imp,sys,string
1893magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1894reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1895open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001896
1897 any byte code file can be used as an executable (i.e. as an argument
1898 to execve(2)).
1899
Tim Peters9940b802000-12-01 07:59:35 +00001900- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001901 character. In 1.6 and earlier, they never produced a sign,
1902 and raised an error if the value of the long was too large
1903 to fit in a Python int. In 2.0, they produced a sign if and
1904 only if too large to fit in an int. This was inconsistent
1905 across platforms (because the size of an int varies across
1906 platforms), and inconsistent with hex() and oct(). Example:
1907
1908 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001909 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001910 'ffffffbe' # in 2.0 and before, on 32-bit machines
1911 >>> hex(-0x42L)
1912 '-0x42L' # in all versions of Python
1913
Tim Peters9940b802000-12-01 07:59:35 +00001914 The behavior of %d formats for negative Python longs remains
1915 the same as in 2.0 (although in 1.6 and before, they raised
1916 an error if the long didn't fit in a Python int).
1917
1918 %u formats don't make sense for Python longs, but are allowed
1919 and treated the same as %d in 2.1. In 2.0, a negative long
1920 formatted via %u produced a sign if and only if too large to
1921 fit in an int. In 1.6 and earlier, a negative long formatted
1922 via %u raised an error if it was too big to fit in an int.
1923
Guido van Rossum3661d392000-12-12 22:10:31 +00001924- Dictionary objects have an odd new method, popitem(). This removes
1925 an arbitrary item from the dictionary and returns it (in the form of
1926 a (key, value) pair). This can be useful for algorithms that use a
1927 dictionary as a bag of "to do" items and repeatedly need to pick one
1928 item. Such algorithms normally end up running in quadratic time;
1929 using popitem() they can usually be made to run in linear time.
1930
Tim Peters36cdad12000-12-29 02:06:45 +00001931Standard library
1932
Thomas Woutersfe385252001-01-19 23:16:56 +00001933- In the time module, the time argument to the functions strftime,
1934 localtime, gmtime, asctime and ctime is now optional, defaulting to
1935 the current time (in the local timezone).
1936
Guido van Rossumda91f222001-01-15 16:36:08 +00001937- The ftplib module now defaults to passive mode, which is deemed a
1938 more useful default given that clients are often inside firewalls
1939 these days. Note that this could break if ftplib is used to connect
1940 to a *server* that is inside a firewall, from outside; this is
1941 expected to be a very rare situation. To fix that, you can call
1942 ftp.set_pasv(0).
1943
Martin v. Löwis10a27872001-01-13 09:54:41 +00001944- The module site now treats .pth files not only for path configuration,
1945 but also supports extensions to the initialization code: Lines starting
1946 with import are executed.
1947
Guido van Rossumf61f1662001-01-10 20:13:55 +00001948- There's a new module, warnings, which implements a mechanism for
1949 issuing and filtering warnings. There are some new built-in
1950 exceptions that serve as warning categories, and a new command line
1951 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1952 turns warnings into errors). warnings.warn(message[, category])
1953 issues a warning message; this can also be called from C as
1954 PyErr_Warn(category, message).
1955
1956- A new module xreadlines was added. This exports a single factory
1957 function, xreadlines(). The intention is that this code is the
1958 absolutely fastest way to iterate over all lines in an open
1959 file(-like) object:
1960
1961 import xreadlines
1962 for line in xreadlines.xreadlines(file):
1963 ...do something to line...
1964
1965 This is equivalent to the previous the speed record holder using
1966 file.readlines(sizehint). Note that if file is a real file object
1967 (as opposed to a file-like object), this is equivalent:
1968
1969 for line in file.xreadlines():
1970 ...do something to line...
1971
Tim Peters36cdad12000-12-29 02:06:45 +00001972- The bisect module has new functions bisect_left, insort_left,
1973 bisect_right and insort_right. The old names bisect and insort
1974 are now aliases for bisect_right and insort_right. XXX_right
1975 and XXX_left methods differ in what happens when the new element
1976 compares equal to one or more elements already in the list: the
1977 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001978 right. Code that doesn't care where equal elements end up should
1979 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001980
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001981- The new curses.panel module wraps the panel library that forms part
1982 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1983
Guido van Rossumf61f1662001-01-10 20:13:55 +00001984- The SocketServer module now sets the allow_reuse_address flag by
1985 default in the TCPServer class.
1986
1987- A new function, sys._getframe(), returns the stack frame pointer of
1988 the caller. This is intended only as a building block for
1989 higher-level mechanisms such as string interpolation.
1990
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001991- The pyexpat module supports a number of new handlers, which are
1992 available only in expat 1.2. If invocation of a callback fails, it
1993 will report an additional frame in the traceback. Parser objects
1994 participate now in garbage collection. If expat reports an unknown
1995 encoding, pyexpat will try to use a Python codec; that works only
1996 for single-byte charsets. The parser type objects is exposed as
1997 XMLParserObject.
1998
1999- xml.dom now offers standard definitions for symbolic node type and
2000 exception code constants, and a hierarchy of DOM exceptions. minidom
2001 was adjusted to use them.
2002
2003- The conformance of xml.dom.minidom to the DOM specification was
2004 improved. It detects a number of additional error cases; the
2005 previous/next relationship works even when the tree is modified;
2006 Node supports the normalize() method; NamedNodeMap, DocumentType and
2007 DOMImplementation classes were added; Element supports the
2008 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2009 method.
2010
Guido van Rossumf61f1662001-01-10 20:13:55 +00002011Build issues
2012
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002013- For Unix (and Unix-compatible) builds, configuration and building of
2014 extension modules is now greatly automated. Rather than having to
2015 edit the Modules/Setup file to indicate which modules should be
2016 built and where their include files and libraries are, a
2017 distutils-based setup.py script now takes care of building most
2018 extension modules. All extension modules built this way are built
2019 as shared libraries. Only a few modules that must be linked
2020 statically are still listed in the Setup file; you won't need to
2021 edit their configuration.
2022
2023- Python should now build out of the box on Cygwin. If it doesn't,
2024 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002025
2026- Python now always uses its own (renamed) implementation of getopt()
2027 -- there's too much variation among C library getopt()
2028 implementations.
2029
2030- C++ compilers are better supported; the CXX macro is always set to a
2031 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002032
Tim Petersd92dfe02000-12-12 01:18:41 +00002033Windows changes
2034
2035- select module: By default under Windows, a select() call
2036 can specify no more than 64 sockets. Python now boosts
2037 this Microsoft default to 512. If you need even more than
2038 that, see the MS docs (you'll need to #define FD_SETSIZE
2039 and recompile Python from source).
2040
Guido van Rossumf61f1662001-01-10 20:13:55 +00002041- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2042 subdirectory is no more!
2043
Tim Petersa3a3a032000-11-30 05:22:44 +00002044
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002045What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002046=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002047
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002048Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002049changes are in the file HISTORY. If you are making the jump directly
2050from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2051HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002052
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002053Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2054the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2055http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002056
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002057--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002058
2059======================================================================
2060
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002061What's new in 2.0 (since release candidate 1)?
2062==============================================
2063
2064Standard library
2065
2066- The copy_reg module was modified to clarify its intended use: to
2067 register pickle support for extension types, not for classes.
2068 pickle() will raise a TypeError if it is passed a class.
2069
2070- Fixed a bug in gettext's "normalize and expand" code that prevented
2071 it from finding an existing .mo file.
2072
2073- Restored support for HTTP/0.9 servers in httplib.
2074
Tim Peters989b7b92000-10-16 20:24:53 +00002075- The math module was changed to stop raising OverflowError in case of
2076 underflow, and return 0 instead in underflow cases. Whether Python
2077 used to raise OverflowError in case of underflow was platform-
2078 dependent (it did when the platform math library set errno to ERANGE
2079 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002080
2081- Fixed a bug in StringIO that occurred when the file position was not
2082 at the end of the file and write() was called with enough data to
2083 extend past the end of the file.
2084
2085- Fixed a bug that caused Tkinter error messages to get lost on
2086 Windows. The bug was fixed by replacing direct use of
2087 interp->result with Tcl_GetStringResult(interp).
2088
2089- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2090 redirect response.
2091
2092- Several changes were made to distutils: Some debugging code was
2093 removed from util. Fixed the installer used when an external zip
2094 program (like WinZip) is not found; the source code for this
2095 installer is in Misc/distutils. check_lib() was modified to behave
2096 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2097 test for whether installed modules are on sys.path was changed to
2098 use both normcase() and normpath().
2099
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002100- Several minor bugs were fixed in the xml package (the minidom,
2101 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002102
2103- The regression test driver (regrtest.py) behavior when invoked with
2104 -l changed: It now reports a count of objects that are recognized as
2105 garbage but not freed by the garbage collector.
2106
Tim Peters989b7b92000-10-16 20:24:53 +00002107- The regression test for the math module was changed to test
2108 exceptional behavior when the test is run in verbose mode. Python
2109 cannot yet guarantee consistent exception behavior across platforms,
2110 so the exception part of test_math is run only in verbose mode, and
2111 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002112
2113Internals
2114
2115- PyOS_CheckStack() has been disabled on Win64, where it caused
2116 test_sre to fail.
2117
2118Build issues
2119
2120- Changed compiler flags, so that gcc is always invoked with -Wall and
2121 -Wstrict-prototypes. Users compiling Python with GCC should see
2122 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002123 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002124 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002125
Tim Petersa3a3a032000-11-30 05:22:44 +00002126- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002127
2128Tools and other miscellany
2129
2130- The compiler in Tools/compiler was updated to support the new
2131 language features introduced in 2.0: extended print statement, list
2132 comprehensions, and augmented assignments. The new compiler should
2133 also be backwards compatible with Python 1.5.2; the compiler will
2134 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002135 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002136
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002137What's new in 2.0 release candidate 1 (since beta 2)?
2138=====================================================
2139
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002140What is release candidate 1?
2141
2142We believe that release candidate 1 will fix all known bugs that we
2143intend to fix for the 2.0 final release. This release should be a bit
2144more stable than the previous betas. We would like to see even more
2145widespread testing before the final release, so we are producing this
2146release candidate. The final release will be exactly the same unless
2147any show-stopping (or brown bag) bugs are found by testers of the
2148release candidate.
2149
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002150All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002151to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002152
2153Core language, builtins, and interpreter
2154
2155- A bug that caused crashes when __coerce__ was used with augmented
2156 assignment, e.g. +=, was fixed.
2157
2158- Raise ZeroDivisionError when raising zero to a negative number,
2159 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2160 power operator and the result of math.pow(0.0, -2.0) will vary by
2161 platform. On Linux, it raises a ValueError.
2162
2163- A bug in Unicode string interpolation was fixed that occasionally
2164 caused errors with formats including "%%". For example, the
2165 following expression "%% %s" % u"abc" no longer raises a TypeError.
2166
2167- Compilation of deeply nested expressions raises MemoryError instead
2168 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2169
2170- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2171 rendering them useless. They are now written in binary mode again.
2172
2173Standard library
2174
2175- Keyword arguments are now accepted for most pattern and match object
2176 methods in SRE, the standard regular expression engine.
2177
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002178- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002179 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002180
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002181- Several bugs in the Unicode handling and error handling in _tkinter
2182 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002183
2184- Fix memory management errors in Merge() and Tkapp_Call() routines.
2185
2186- Several changes were made to cStringIO to make it compatible with
2187 the file-like object interface and with StringIO. If operations are
2188 performed on a closed object, an exception is raised. The truncate
2189 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002190 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002191
2192- There were many changes made to the linuxaudiodev module and its
2193 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002194 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002195
2196 Note that this module is named poorly, because it should work
2197 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002198 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002199
2200 The module now raises exceptions when errors occur instead of
2201 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2202 audio) and defines a getptr() method that calls the
2203 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2204
2205- The library_version attribute, introduced in an earlier beta, was
2206 removed because it can not be supported with early versions of the C
2207 readline library, which provides no way to determine the version at
2208 compile-time.
2209
2210- The binascii module is now enabled on Win64.
2211
Tim Peters46446d62000-10-09 21:19:31 +00002212- tokenize.py no longer suffers "recursion depth" errors when parsing
2213 programs with very long string literals.
2214
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002215Internals
2216
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002217- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002218 which is called when the interpreter starts up to determine where
2219 the standard library is installed. These vulnerabilities affect all
2220 previous versions of Python and can be exploited by setting very
2221 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2222 setuid Python script, although use of the wrapper in
2223 Misc/setuid-prog.c will eliminate the vulnerability.
2224
2225- Fixed garbage collection bugs in instance creation that were
2226 triggered when errors occurred during initialization. The solution,
2227 applied in cPickle and in PyInstance_New(), is to call
2228 PyObject_GC_Init() after the initialization of the object's
2229 container attributes is complete.
2230
2231- pyexpat adds definitions of PyModule_AddStringConstant and
2232 PyModule_AddObject if the Python version is less than 2.0, which
2233 provides compatibility with PyXML on Python 1.5.2.
2234
2235- If the platform has a bogus definition for LONG_BIT (the number of
2236 bits in a long), an error will be reported at compile time.
2237
2238- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2239 collection crashes and possibly other, unreported crashes.
2240
2241- Fixed a memory leak in _PyUnicode_Fini().
2242
2243Build issues
2244
2245- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002246 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002247 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002248
2249- The mmap.PAGESIZE constant is now initialized using sysconf when
2250 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2251
2252- The md5 file should now compile on all platforms.
2253
2254- The select module now compiles on platforms that do not define
2255 POLLRDNORM and related constants.
2256
2257- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002258 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002259
Jeremy Hylton10921202000-10-09 18:34:12 +00002260- BeOS: A number of changes were made to the build and installation
2261 process. ar-fake now operates on a directory of object files.
2262 dl_export.h is gone, and its macros now appear on the mwcc command
2263 line during build on PPC BeOS.
2264
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002265- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002266 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002267
2268- Cygwin: Support for shared libraries, Tkinter, and sockets.
2269
2270- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2271
2272Tools and other miscellany
2273
2274- Removed debugging prints from main used with freeze.
2275
Tim Peters46446d62000-10-09 21:19:31 +00002276- IDLE auto-indent no longer crashes when it encounters Unicode
2277 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002278
2279What's new in 2.0 beta 2 (since beta 1)?
2280========================================
2281
2282Core language, builtins, and interpreter
2283
Tim Peters482c0212000-09-26 06:33:09 +00002284- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002285 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002286
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002287- Add -h and -V command line options to print the usage message and
2288 Python version number and exit immediately.
2289
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002290- eval() and exec accept Unicode objects as code parameters.
2291
2292- getattr() and setattr() now also accept Unicode objects for the
2293 attribute name, which are converted to strings using the default
2294 encoding before lookup.
2295
2296- Multiplication on string and Unicode now does proper bounds
2297 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2298 string is too long."
2299
2300- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002301 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002302
Jeremy Hylton1b618592000-09-26 05:32:36 +00002303
2304Standard library and extensions
2305
Guido van Rossum5b08f132001-04-16 02:05:23 +00002306- socket module: the OpenSSL code now adds support for RAND_status()
2307 and EGD (Entropy Gathering Device).
2308
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002309- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002310 argument checking; it still takes no arguments.
2311
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002312- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002313
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002314- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002315
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002316- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002317
2318- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002319 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002320
2321- copy: Copy Unicode objects atomically.
2322
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002323- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002324
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002325- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002326
Fred Drake67233bc2000-09-26 16:40:27 +00002327- dbm: Add get() and setdefault() methods to dbm object. Add constant
2328 `library' to module that names the library used. Added doc strings
2329 and method names to error messages. Uses configure to determine
2330 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2331 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002332
2333- distutils: Update to version 0.9.3.
2334
2335- dl: Add several dl.RTLD_ constants.
2336
2337- fpectl: Now supported on FreeBSD.
2338
2339- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2340 found by the collector will be saved in gc.garbage. This is useful
2341 for debugging a program that creates reference cycles.
2342
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002343- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002344 of HTTP class. Do not close socket on zero-length response. Do not
2345 crash when server sends invalid content-length header.
2346
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002347- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002348
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002349- marshal: When reading a short, sign-extend on platforms where shorts
2350 are bigger than 16 bits. When reading a long, repair the unportable
2351 sign extension that was being done for 64-bit machines. (It assumed
2352 that signed right shift sign-extends.)
2353
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002354- operator: Add contains(), invert(), __invert__() as aliases for
2355 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002356
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002357- os: Add support for popen2() and popen3() on all platforms where
2358 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002359
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002360- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002361 clicking on a file in Explorer (or passing the file name to the
2362 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002363
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002364- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002365 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002366
2367- pickle: Now raises ValueError when an invalid pickle that contains
2368 a non-string repr where a string repr was expected. This behavior
2369 matches cPickle.
2370
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002371- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002372
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002373- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002374
2375- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002376 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002377 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002378
2379- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002380 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002381
2382- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002383 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002384 few cycles during startup since the first call to
2385 setdefaultencoding() will initialize the codec registry and the
2386 encodings package.
2387
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002388- socket: Support for size hint in readlines() method of object returned
2389 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002390
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002391- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002392 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002393 is followed by whitespace.
2394
Tim Petersa3a3a032000-11-30 05:22:44 +00002395- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002396
2397- struct: Check ranges for bytes and shorts.
2398
2399- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002400 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002401
2402- Tkinter: Image objects are now guaranteed to have unique ids. Set
2403 event.delta to zero if Tk version doesn't support mousewheel.
2404 Removed some debugging prints.
2405
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002406- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002407
Fred Drake67233bc2000-09-26 16:40:27 +00002408- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002409 which works around a bug in Norton AntiVirus 2000 that leads directly
2410 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002411
2412- xml: New version detection code allows PyXML to override standard
2413 XML package if PyXML version is greater than 0.6.1.
2414
Fred Drake64bb3802000-09-26 16:21:35 +00002415- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2416 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2417 tree only for nodes which are sufficiently interesting to a specific
2418 application. Does not provide the HTML-specific extensions. Still
2419 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002420
Fred Drake64bb3802000-09-26 16:21:35 +00002421- xml.sax: SAX 2 support for Python, including all the handler
2422 interfaces needed to process XML 1.0 compliant XML. Some
2423 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002424
Fred Drake64bb3802000-09-26 16:21:35 +00002425- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2426 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002427
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002428
Jeremy Hylton1b618592000-09-26 05:32:36 +00002429C API
2430
2431- Add three new convenience functions for module initialization --
2432 PyModule_AddObject(), PyModule_AddIntConstant(), and
2433 PyModule_AddStringConstant().
2434
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002435- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002436 removed and add #error to Python.h if NULL isn't defined after
2437 #include of stdio.h.
2438
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002439- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002440 backwards compatibility (at the source level) with old extensions.
2441
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002442- A wrapper API was added for signal() and sigaction(). Instead of
2443 either function, always use PyOS_getsig() to get a signal handler
2444 and PyOS_setsig() to set one. A new convenience typedef
2445 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002446
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002447- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002448 internal data buffer and size of a string object -- or the default
2449 encoded version of a Unicode object.
2450
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002451- PyString_Size() and PyString_AsString() accept Unicode objects.
2452
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002453- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002454 exists). INT_MAX and LONG_MAX will always be defined, even if
2455 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002456
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002457- PyFloat_FromString takes a second argument, pend, that was
2458 effectively useless. It is now officially useless but preserved for
2459 backwards compatibility. If the pend argument is not NULL, *pend is
2460 set to NULL.
2461
2462- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2463 for the attribute name. See note on getattr() above.
2464
2465- A few bug fixes to argument processing for Unicode.
2466 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2467 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2468 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002469 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002470
2471- Py_BuildValue accepts B format (for bgen-generated code).
2472
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002473
Jeremy Hylton1b618592000-09-26 05:32:36 +00002474Internals
2475
2476- On Unix, fix code for finding Python installation directory so that
2477 it works when argv[0] is a relative path.
2478
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002479- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002480 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002481 rather than by generating a copy of the object.
2482
Tim Peters482c0212000-09-26 06:33:09 +00002483- Several of the internal Unicode tables are much smaller now, and
2484 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002485
Jeremy Hylton97693b02000-09-26 17:42:51 +00002486- In the garbage collector: Fixed bug in collection of tuples. Fixed
2487 bug that caused some instances to be removed from the container set
2488 while they were still live. Fixed parsing in gc.set_debug() for
2489 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002490
2491- Fixed refcount problem in instance deallocation that only occurred
2492 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2493
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002494- On Windows, getpythonregpath is now protected against null data in
2495 registry key.
2496
2497- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002498 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002499
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002500
Jeremy Hylton1b618592000-09-26 05:32:36 +00002501Build and platform-specific issues
2502
2503- Better support of GNU Pth via --with-pth configure option.
2504
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002505- Python/C API now properly exposed to dynamically-loaded extension
2506 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002507
2508- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2509 Don't define MS_SYNC to be zero when it is undefined. Added missing
2510 prototypes in posixmodule.c.
2511
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002512- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002513 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002514
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002515- Fix largefile support on older NetBSD systems and OpenBSD by adding
2516 define for TELL64.
2517
2518
2519Tools and other miscellany
2520
2521- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2522
2523- freeze: The modulefinder now works with 2.0 opcodes.
2524
Tim Petersa3a3a032000-11-30 05:22:44 +00002525- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002526 Move hackery of sys.argv until after the Tk instance has been
2527 created, which allows the application-specific Tkinter
2528 initialization to be executed if present; also pass an explicit
2529 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002530
Jeremy Hylton1b618592000-09-26 05:32:36 +00002531
2532What's new in 2.0 beta 1?
2533=========================
2534
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002535Source Incompatibilities
2536------------------------
2537
2538None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2539such as single-argument append(), connect() and bind(), and changes to
2540str(long) and repr(float).
2541
2542
2543Binary Incompatibilities
2544------------------------
2545
2546- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2547with Python 2.0; these extensions will have to be rebuilt for Python
25482.0.
2549
2550- On Windows, attempting to import a third party extension built for
2551Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2552can do about this. Check your PYTHONPATH environment variable!
2553
2554- Python bytecode files (*.pyc and *.pyo) are not compatible between
2555releases.
2556
2557
2558Overview of Changes Since 1.6
2559-----------------------------
2560
2561There are many new modules (including brand new XML support through
2562the xml package, and i18n support through the gettext module); a list
2563of all new modules is included below. Lots of bugs have been fixed.
2564
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002565The process for making major new changes to the language has changed
2566since Python 1.6. Enhancements must now be documented by a Python
2567Enhancement Proposal (PEP) before they can be accepted.
2568
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002569There are several important syntax enhancements, described in more
2570detail below:
2571
2572 - Augmented assignment, e.g. x += 1
2573
2574 - List comprehensions, e.g. [x**2 for x in range(10)]
2575
2576 - Extended import statement, e.g. import Module as Name
2577
2578 - Extended print statement, e.g. print >> file, "Hello"
2579
2580Other important changes:
2581
2582 - Optional collection of cyclical garbage
2583
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002584Python Enhancement Proposal (PEP)
2585---------------------------------
2586
2587PEP stands for Python Enhancement Proposal. A PEP is a design
2588document providing information to the Python community, or describing
2589a new feature for Python. The PEP should provide a concise technical
2590specification of the feature and a rationale for the feature.
2591
2592We intend PEPs to be the primary mechanisms for proposing new
2593features, for collecting community input on an issue, and for
2594documenting the design decisions that have gone into Python. The PEP
2595author is responsible for building consensus within the community and
2596documenting dissenting opinions.
2597
2598The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002599
2600Augmented Assignment
2601--------------------
2602
2603This must have been the most-requested feature of the past years!
2604Eleven new assignment operators were added:
2605
Guido van Rossume905e952000-09-05 12:42:46 +00002606 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002607
2608For example,
2609
2610 A += B
2611
2612is similar to
2613
2614 A = A + B
2615
2616except that A is evaluated only once (relevant when A is something
2617like dict[index].attr).
2618
2619However, if A is a mutable object, A may be modified in place. Thus,
2620if A is a number or a string, A += B has the same effect as A = A+B
2621(except A is only evaluated once); but if a is a list, A += B has the
2622same effect as A.extend(B)!
2623
2624Classes and built-in object types can override the new operators in
2625order to implement the in-place behavior; the not-in-place behavior is
2626used automatically as a fallback when an object doesn't implement the
2627in-place behavior. For classes, the method name is derived from the
2628method name for the corresponding not-in-place operator by inserting
2629an 'i' in front of the name, e.g. __iadd__ implements in-place
2630__add__.
2631
2632Augmented assignment was implemented by Thomas Wouters.
2633
2634
2635List Comprehensions
2636-------------------
2637
2638This is a flexible new notation for lists whose elements are computed
2639from another list (or lists). The simplest form is:
2640
2641 [<expression> for <variable> in <sequence>]
2642
Guido van Rossum56db0952000-09-06 23:34:25 +00002643For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002644This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002645
2646You can also add a condition:
2647
2648 [<expression> for <variable> in <sequence> if <condition>]
2649
2650For example, [w for w in words if w == w.lower()] would yield the list
2651of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002652than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002653
2654You can also have nested for loops and more than one 'if' clause. For
2655example, here's a function that flattens a sequence of sequences::
2656
2657 def flatten(seq):
2658 return [x for subseq in seq for x in subseq]
2659
2660 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2661
2662This prints
2663
2664 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2665
2666List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002667Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002668
2669
2670Extended Import Statement
2671-------------------------
2672
2673Many people have asked for a way to import a module under a different
2674name. This can be accomplished like this:
2675
2676 import foo
2677 bar = foo
2678 del foo
2679
2680but this common idiom gets old quickly. A simple extension of the
2681import statement now allows this to be written as follows:
2682
2683 import foo as bar
2684
2685There's also a variant for 'from ... import':
2686
2687 from foo import bar as spam
2688
2689This also works with packages; e.g. you can write this:
2690
2691 import test.regrtest as regrtest
2692
2693Note that 'as' is not a new keyword -- it is recognized only in this
2694context (this is only possible because the syntax for the import
2695statement doesn't involve expressions).
2696
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002697Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002698
2699
2700Extended Print Statement
2701------------------------
2702
2703Easily the most controversial new feature, this extension to the print
2704statement adds an option to make the output go to a different file
2705than the default sys.stdout.
2706
2707For example, to write an error message to sys.stderr, you can now
2708write:
2709
2710 print >> sys.stderr, "Error: bad dog!"
2711
2712As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002713evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002714
2715 print >> None, "Hello world"
2716
2717is equivalent to
2718
2719 print "Hello world"
2720
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002721Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002722
2723
2724Optional Collection of Cyclical Garbage
2725---------------------------------------
2726
2727Python is now equipped with a garbage collector that can hunt down
2728cyclical references between Python objects. It's no replacement for
2729reference counting; in fact, it depends on the reference counts being
2730correct, and decides that a set of objects belong to a cycle if all
2731their reference counts can be accounted for from their references to
2732each other. This devious scheme was first proposed by Eric Tiedemann,
2733and brought to implementation by Neil Schemenauer.
2734
2735There's a module "gc" that lets you control some parameters of the
2736garbage collection. There's also an option to the configure script
2737that lets you enable or disable the garbage collection. In 2.0b1,
2738it's on by default, so that we (hopefully) can collect decent user
2739experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002740performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002741off by default in the final 2.0 release.
2742
2743
2744Smaller Changes
2745---------------
2746
2747A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2748map(None, seq1, seq2, ...) when the sequences have the same length;
2749i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2750the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002751zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002752
2753sys.version_info is a tuple (major, minor, micro, level, serial).
2754
2755Dictionaries have an odd new method, setdefault(key, default).
2756dict.setdefault(key, default) returns dict[key] if it exists; if not,
2757it sets dict[key] to default and returns that value. Thus:
2758
2759 dict.setdefault(key, []).append(item)
2760
2761does the same work as this common idiom:
2762
2763 if not dict.has_key(key):
2764 dict[key] = []
2765 dict[key].append(item)
2766
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002767There are two new variants of SyntaxError that are raised for
2768indentation-related errors: IndentationError and TabError.
2769
2770Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2771escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002772
2773The limits on the size of expressions and file in Python source code
2774have been raised from 2**16 to 2**32. Previous versions of Python
2775were limited because the maximum argument size the Python VM accepted
2776was 2**16. This limited the size of object constructor expressions,
2777e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2778limit was raised thanks to a patch by Charles Waldman that effectively
2779fixes the problem. It is now much more likely that you will be
2780limited by available memory than by an arbitrary limit in Python.
2781
2782The interpreter's maximum recursion depth can be modified by Python
2783programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2784limit is the maximum number of recursive calls that can be made by
2785Python code. The limit exists to prevent infinite recursion from
2786overflowing the C stack and causing a core dump. The default value is
27871000. The maximum safe value for a particular platform can be found
2788by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002789
2790New Modules and Packages
2791------------------------
2792
2793atexit - for registering functions to be called when Python exits.
2794
2795imputil - Greg Stein's alternative API for writing custom import
2796hooks.
2797
2798pyexpat - an interface to the Expat XML parser, contributed by Paul
2799Prescod.
2800
2801xml - a new package with XML support code organized (so far) in three
2802subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2803would fill a volume. There's a special feature whereby a
2804user-installed package named _xmlplus overrides the standard
2805xmlpackage; this is intended to give the XML SIG a hook to distribute
2806backwards-compatible updates to the standard xml package.
2807
2808webbrowser - a platform-independent API to launch a web browser.
2809
2810
Guido van Rossume905e952000-09-05 12:42:46 +00002811Changed Modules
2812---------------
2813
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002814array -- new methods for array objects: count, extend, index, pop, and
2815remove
2816
2817binascii -- new functions b2a_hex and a2b_hex that convert between
2818binary data and its hex representation
2819
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002820calendar -- Many new functions that support features including control
2821over which day of the week is the first day, returning strings instead
2822of printing them. Also new symbolic constants for days of week,
2823e.g. MONDAY, ..., SUNDAY.
2824
2825cgi -- FieldStorage objects have a getvalue method that works like a
2826dictionary's get method and returns the value attribute of the object.
2827
2828ConfigParser -- The parser object has new methods has_option,
2829remove_section, remove_option, set, and write. They allow the module
2830to be used for writing config files as well as reading them.
2831
2832ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002833optionally support the RFC 959 REST command.
2834
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002835gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002836
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002837httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2838the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002839
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002840locale -- implement getdefaultlocale for Win32 and Macintosh
2841
2842marshal -- no longer dumps core when marshaling deeply nested or
2843recursive data structures
2844
2845os -- new functions isatty, seteuid, setegid, setreuid, setregid
2846
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002847os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2848support under Unix.
2849
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002850os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002851
2852os.path -- fix semantics of os.path.commonprefix
2853
2854smtplib -- support for sending very long messages
2855
2856socket -- new function getfqdn()
2857
2858readline -- new functions to read, write and truncate history files.
2859The readline section of the library reference manual contains an
2860example.
2861
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002862select -- add interface to poll system call
2863
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002864shutil -- new copyfileobj function
2865
2866SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2867HTTP server.
2868
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002869Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002870
2871urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002872e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002873
2874whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002875
2876
2877Obsolete Modules
2878----------------
2879
2880None. However note that 1.6 made a whole slew of modules obsolete:
2881stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2882poly, zmod, strop, util, whatsound.
2883
2884
2885Changed, New, Obsolete Tools
2886----------------------------
2887
Tim Peters8b092332000-09-05 20:15:25 +00002888None.
Guido van Rossume905e952000-09-05 12:42:46 +00002889
2890
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002891C-level Changes
2892---------------
2893
2894Several cleanup jobs were carried out throughout the source code.
2895
2896All C code was converted to ANSI C; we got rid of all uses of the
2897Py_PROTO() macro, which makes the header files a lot more readable.
2898
2899Most of the portability hacks were moved to a new header file,
2900pyport.h; several other new header files were added and some old
2901header files were removed, in an attempt to create a more rational set
2902of header files. (Few of these ever need to be included explicitly;
2903they are all included by Python.h.)
2904
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002905Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002906and Win64, especially for the new Intel Itanium processor. Mick also
2907added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002908
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002909The C APIs to return an object's size have been update to consistently
2910use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2911previous versions, the abstract interfaces used PyXXX_Length and the
2912concrete interfaces used PyXXX_Size. The old names,
2913e.g. PyObject_Length, are still available for backwards compatibility
2914at the API level, but are deprecated.
2915
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002916The PyOS_CheckStack function has been implemented on Windows by
2917Fredrik Lundh. It prevents Python from failing with a stack overflow
2918on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002919
2920The GC changes resulted in creation of two new slots on object,
2921tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002922the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002923
2924The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002925C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002926
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002927PyErr_Format has been updated to automatically calculate the size of
2928the buffer needed to hold the formatted result string. This change
2929prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002930
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002931New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002932
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002933PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2934that are the same as their non-Ex counterparts except they take an
2935extra flag argument that tells them to close the file when done.
2936
2937XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002938
Tim Peters8b092332000-09-05 20:15:25 +00002939
2940Windows Changes
2941---------------
2942
2943New popen2/popen3/peopen4 in os module (see Changed Modules above).
2944
2945os.popen is much more usable on Windows 95 and 98. See Microsoft
2946Knowledge Base article Q150956. The Win9x workaround described there
2947is implemented by the new w9xpopen.exe helper in the root of your
2948Python installation. Note that Python uses this internally; it is not
2949a standalone program.
2950
2951Administrator privileges are no longer required to install Python
2952on Windows NT or Windows 2000. If you have administrator privileges,
2953Python's registry info will be written under HKEY_LOCAL_MACHINE.
2954Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002955under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002956uses of Python, but will prevent some advanced uses from working
2957(for example, running a Python script as an NT service, or possibly
2958from CGI).
2959
2960[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2961installer; instead, it installs the needed Tcl/Tk files directly in the
2962Python directory. If you already have a Tcl/Tk installation, this
2963wastes some disk space (about 4 Megs) but avoids problems with
2964conflicting Tcl/Tk installations, and makes it much easier for Python
2965to ensure that Tcl/Tk can find all its files.
2966
2967[This was new in 1.6] The Windows installer now installs by default in
2968\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2969
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002970
2971Updates to the changes between 1.5.2 and 1.6
2972--------------------------------------------
2973
2974The 1.6 NEWS file can't be changed after the release is done, so here
2975is some late-breaking news:
2976
2977New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2978and changes to getlocale() and setlocale().
2979
2980The new module is now enabled per default.
2981
2982It is not true that the encodings codecs cannot be used for normal
2983strings: the string.encode() (which is also present on 8-bit strings
2984!) allows using them for 8-bit strings too, e.g. to convert files from
2985cp1252 (Windows) to latin-1 or vice-versa.
2986
2987Japanese codecs are available from Tamito KAJIYAMA:
2988http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2989
2990
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002991======================================================================