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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
15Tools/Demos
16
17Build
18
19C API
20
21New platforms
22
23Tests
24
25Windows
26
27Mac
28
29
Tim Peters84362bc2001-10-19 17:55:30 +000030What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +000031Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +000032===========================
33
34Type/class unification and new-style classes
35
Guido van Rossum3d27df02001-11-15 20:27:54 +000036- Multiple inheritance mixing new-style and classic classes in the
37 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +000038
39 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000040 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000041
42 The MRO (method resolution order) for each base class is respected
43 according to its kind, but the MRO for the derived class is computed
44 using new-style MRO rules if any base clase is a new-style class.
45 This needs to be documented.
46
Tim Petersa427a2b2001-10-29 22:25:45 +000047- The new builtin dictionary() constructor, and dictionary type, have
48 been renamed to dict. This reflects a decade of common usage.
49
Guido van Rossum3fc08d22001-11-15 20:33:10 +000050- dict() now accepts an iterable object producing 2-sequences. For
51 example, dict(d.items()) == d for any dictionary d. The argument,
52 and the elements of the argument, can be any iterable objects.
53
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000054- New-style classes can now have a __del__ method, which is called
55 when the instance is deleted (just like for classic classes).
56
Guido van Rossum12d955c2001-10-26 14:56:06 +000057- Assignment to object.__dict__ is now possible, for objects that are
58 instances of new-style classes that have a __dict__ (unless the base
59 class forbids it).
60
Guido van Rossumc8e56452001-10-22 00:43:43 +000061- Methods of built-in types now properly check for keyword arguments
62 (formerly these were silently ignored). The only built-in methods
63 that take keyword arguments are __call__, __init__ and __new__.
64
Guido van Rossum86443212001-10-27 22:28:54 +000065- The socket function has been converted to a type; see below.
66
Tim Peters84362bc2001-10-19 17:55:30 +000067Core and builtins
68
Jeremy Hylton249aaed2001-11-09 21:06:24 +000069- Assignment to __debug__ raises SyntaxError at compile-time. This
70 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +000071 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +000072
Guido van Rossum12d955c2001-10-26 14:56:06 +000073- Clarified the error messages for unsupported operands to an operator
74 (like 1 + '').
75
Tim Peters84362bc2001-10-19 17:55:30 +000076Extension modules
77
Tim Peters5ebfd362001-11-13 23:11:19 +000078- mmap has a new keyword argument, "access", allowing a uniform way for
79 both Windows and Unix users to create read-only, write-through and
80 copy-on-write memory mappings. This was previously possible only on
81 Unix. A new keyword argument was required to support this in a
82 uniform way because the mmap() signuatures had diverged across
83 platforms. Thanks to Jay T Miller for repairing this!
84
Tim Peters169ded02001-11-03 19:57:21 +000085- By default, the gc.garbage list now contains only those instances in
86 unreachable cycles that have __del__ methods; in 2.1 it contained all
87 instances in unreachable cycles. "Instances" here has been generalized
88 to include instances of both new-style and old-style classes.
89
Guido van Rossum12d955c2001-10-26 14:56:06 +000090- The socket module defines a new method for socket objects,
91 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000092 send() until all data has been sent. Also, the socket function has
93 been converted to a subclassable type, like list and tuple (etc.)
94 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000095
96- Various bugfixes to the curses module. There is now a test suite
97 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +000098
Guido van Rossum692adf12001-10-30 03:03:03 +000099- binascii.b2a_base64 no longer places an arbitrary restriction of 57
100 bytes on its input.
101
Tim Peters84362bc2001-10-19 17:55:30 +0000102Library
103
Tim Peters5ebfd362001-11-13 23:11:19 +0000104- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000105 convenience function.
106
Tim Peters75335872001-11-03 19:35:43 +0000107- Symbolic group names in regular expressions must be unique. For
108 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
109 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000110 Python 2.2 detects this error at regexp compilation time;
111 previously, the error went undetected, and results were
112 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
113 pattern.subn() methods have been rewritten in C. Also, an
114 experimental function/method finditer() has been added, which works
115 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000116
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000117- Tix exposes more commands through the classes DirSelectBox,
118 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
119 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
120 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
121
Tim Peters98791af2001-10-23 01:59:54 +0000122- Traceback objects are now scanned by cyclic garbage collection, so
123 cycles created by casual use of sys.exc_info() no longer cause
124 permanent memory leaks (provided garbage collection is enabled).
125
Guido van Rossum49192142001-10-24 20:51:44 +0000126- os.extsep -- a new variable needed by the RISCOS support. It is the
127 separator used by extensions, and is '.' on all platforms except
128 RISCOS, where it is '/'. There is no need to use this variable
129 unless you have a masochistic desire to port your code to RISCOS.
130
Barry Warsaw012852b2001-11-16 16:17:27 +0000131- mimetypes.py has optional support for non-standard, but commonly
132 found types. guess_type() and guess_extension() now accept an
133 optional `strict' flag, defaulting to true, which controls whether
134 recognize non-standard types or not. A few non-standard types we
135 know about have been added. Also, when run as a script, there are
136 new -l and -e options.
137
138- statcache is now deprecated.
139
140- email.Utils.formatdate() now produces the preferred RFC 2822 style
141 dates with numeric timezones (it used to produce obsolete dates
142 hard coded to "GMT" timezone). An optional `localtime' flag is
143 added to produce dates in the local timezone, with daylight savings
144 time properly taken into account.
145
146- In pickle and cPickle, instead of masking errors in load() by
147 transforming them into SystemError, we let the original exception
148 propagate out. Also, implement support for __safe_for_unpickling__
149 in pickle, as it already was supported in cPickle.
150
Tim Peters84362bc2001-10-19 17:55:30 +0000151Tools/Demos
152
153Build
154
Barry Warsaw012852b2001-11-16 16:17:27 +0000155- The dbm module is built using libdb1 if available. The bsddb module
156 is built with libdb3 if available.
157
158- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
159
Tim Peters84362bc2001-10-19 17:55:30 +0000160C API
161
Tim Peters1fc240e2001-10-26 05:06:50 +0000162- New function PySequence_Fast_GET_SIZE() returns the size of a non-
163 NULL result from PySequence_Fast(), more quickly than calling
164 PySequence_Size().
165
Barry Warsaw012852b2001-11-16 16:17:27 +0000166- New argument unpacking function PyArg_UnpackTuple() added.
167
168- New functions PyObject_CallFunctionObjArgs() and
169 PyObject_CallMethodObjArgs() have been added to make it more
170 convenient and efficient to call functions and methods from C.
171
172- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
173 possible that this will propagate errors it didn't before.
174
175- New function PyObject_CheckReadBuffer(), which returns true if its
176 argument supports the single-segment readable buffer interface.
177
Tim Peters84362bc2001-10-19 17:55:30 +0000178New platforms
179
Guido van Rossum86443212001-10-27 22:28:54 +0000180- We've finally confirmed that this release builds on HP-UX 11.00,
181 *with* threads, and passes the test suite.
182
Tim Peters7a33d8b2001-11-05 02:51:07 +0000183- Thanks to a series of patches from Michael Muller, Python may build
184 again under OS/2 Visual Age C++.
185
Guido van Rossum49192142001-10-24 20:51:44 +0000186- Updated RISCOS port by Dietmar Schwertberger.
187
Tim Peters84362bc2001-10-19 17:55:30 +0000188Tests
189
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000190- Added a test script for the curses module. It isn't run automatically;
191 regrtest.py must be run with '-u curses' to enable it.
192
Tim Peters84362bc2001-10-19 17:55:30 +0000193Windows
194
Barry Warsaw012852b2001-11-16 16:17:27 +0000195Mac
196
197- PythonScript has been moved to unsupported and is slated to be
198 removed completely in the next release.
199
200- It should now be possible to build applets that work on both OS9 and
201 OSX.
202
203- The core is now linked with CoreServices not Carbon; as a side
204 result, default 8bit encoding on OSX is now ASCII.
205
206- Python should now build on OSX 10.1.1
207
Tim Peters84362bc2001-10-19 17:55:30 +0000208
Tim Petersabf925f2001-09-28 21:53:42 +0000209What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000210Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000211===========================
212
213Type/class unification and new-style classes
214
Guido van Rossum687ae002001-10-15 22:03:32 +0000215- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000216 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000217 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000218 remains: the __dict__ of a new-style class is a read-only proxy; you
219 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000220 __defined__ attribute of new-style types no longer exists, for lack
221 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000222 future a __cache__ may be resurrected with a similar function, if I
223 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000224
Tim Peters1c9ca872001-10-04 06:43:12 +0000225- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
226 always returned None, even when there was a class docstring).
227
228- doctest now finds and runs docstrings attached to new-style classes,
229 class methods, static methods, and properties.
230
Guido van Rossum9074ef62001-10-16 21:34:49 +0000231Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000232
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000233- A very subtle syntactical pitfall in list comprehensions was fixed.
234 For example: [a+b for a in 'abc', for b in 'def']. The comma in
235 this example is a mistake. Previously, this would silently let 'a'
236 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
237 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
238 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
239 Note that [a for a in <singleton>] is a convoluted way to say
240 [<singleton>] anyway, so it's not like any expressiveness is lost.
241
Guido van Rossum9074ef62001-10-16 21:34:49 +0000242- getattr(obj, name, default) now only catches AttributeError, as
243 documented, rather than returning the default value for all
244 exceptions (which could mask bugs in a __getattr__ hook, for
245 example).
246
Fred Drakecb7a6b52001-10-22 18:41:51 +0000247- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000248 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000249 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000250 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000251
Guido van Rossum1c486092001-10-19 02:05:35 +0000252- unicode(obj) now behaves more like str(obj), accepting arbitrary
253 objects, and calling a __unicode__ method if it exists.
254 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000255 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000256
Barry Warsawf6fb1712001-10-19 05:35:40 +0000257- isinstance() now allows any object as the first argument and a
258 class, a type or something with a __bases__ tuple attribute for the
259 second argument. The second argument may also be a tuple of a
260 class, type, or something with __bases__, in which case isinstance()
261 will return true if the first argument is an instance of any of the
262 things contained in the second argument tuple. E.g.
263
264 isinstance(x, (A, B))
265
266 returns true if x is an instance of A or B.
267
Guido van Rossum9074ef62001-10-16 21:34:49 +0000268Extension modules
269
270- thread.start_new_thread() now returns the thread ID (previously None).
271
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000272- binascii has now two quopri support functions, a2b_qp and b2a_qp.
273
Guido van Rossumc524d952001-10-19 01:31:59 +0000274- readline now supports setting the startup_hook and the
275 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000276
Guido van Rossumc524d952001-10-19 01:31:59 +0000277- os and posix supports chroot(), setgroups() and unsetenv() where
278 available. The stat(), fstat(), statvfs() and fstatvfs() functions
279 now return "pseudo-sequences" -- the various fields can now be
280 accessed as attributes (e.g. os.stat("/").st_mtime) but for
281 backwards compatibility they also behave as a fixed-length sequence.
282 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000283 attributes.
284
285- time: localtime(), gmtime() and strptime() now return a
286 pseudo-sequence similar to the os.stat() return value, with
287 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000288
Guido van Rossum9074ef62001-10-16 21:34:49 +0000289- Decompression objects in the zlib module now accept an optional
290 second parameter to decompress() that specifies the maximum amount
291 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000292
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000293- optional SSL support in the socket module now exports OpenSSL
294 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
295 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000296 automatically seed its PRNG. Also, the keyfile and certfile
297 arguments to socket.ssl() are now optional.
298
299- posixmodule (and by extension, the os module on POSIX platforms) now
300 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000301
Guido van Rossum9074ef62001-10-16 21:34:49 +0000302Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000303
Tim Peters7402f792001-10-02 03:53:41 +0000304- doctest now excludes functions and classes not defined by the module
305 being tested, thanks to Tim Hochberg.
306
Fred Drakecb7a6b52001-10-22 18:41:51 +0000307- HotShot, a new profiler implemented using a C-based callback, has
308 been added. This substantially reduces the overhead of profiling,
309 but it is still quite preliminary. Support modules and
310 documentation will be added in upcoming releases (before 2.2 final).
311
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000312- profile now produces correct output in situations where an exception
313 raised in Python is cleared by C code (e.g. hasattr()). This used
314 to cause wrong output, including spurious claims of recursive
315 functions and attribution of time spent to the wrong function.
316
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000317 The code and documentation for the derived OldProfile and HotProfile
318 profiling classes was removed. The code hasn't worked for years (if
319 you tried to use them, they raised exceptions). OldProfile
320 intended to reproduce the behavior of the profiler Python used more
321 than 7 years ago, and isn't interesting anymore. HotProfile intended
322 to provide a faster profiler (but producing less information), and
323 that's a worthy goal we intend to meet via a different approach (but
324 without losing information).
325
Tim Peterscce092d2001-10-09 05:31:56 +0000326- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000327 a much better system-specific calibration constant. The constant can
328 now be specified in an instance constructor, or as a Profile class or
329 instance variable, instead of by editing profile.py's source code.
330 Calibration must still be done manually (see the docs for the profile
331 module).
332
333 Note that Profile.calibrate() must be overriden by subclasses.
334 Improving the accuracy required exploiting detailed knowledge of
335 profiler internals; the earlier method abstracted away the details
336 and measured a simplified model instead, but consequently computed
337 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000338
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000339- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000340 which indicates whether output is intended for the header 'Q'
341 encoding.
342
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000343- The SocketServer.ThreadingMixIn class now closes the request after
344 finish_request() returns. (Not when it errors out though.)
345
Barry Warsawf6fb1712001-10-19 05:35:40 +0000346- The nntplib module's NNTP.body() method has grown a `file' argument
347 to allow saving the message body to a file.
348
349- The email package has added a class email.Parser.HeaderParser which
350 only parses headers and does not recurse into the message's body.
351 Also, the module/class MIMEAudio has been added for representing
352 audio data (contributed by Anthony Baxter).
353
354- ftplib should be able to handle files > 2GB.
355
356- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
357 ON, and OFF.
358
Fred Drakecb7a6b52001-10-22 18:41:51 +0000359- xml.dom.minidom NodeList objects now support the length attribute
360 and item() method as required by the DOM specifications.
361
Guido van Rossumed554f62001-10-02 23:15:37 +0000362Tools/Demos
363
364- Demo/dns was removed. It no longer serves any purpose; a package
365 derived from it is now maintained by Anthony Baxter, see
366 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000367
Barry Warsawf6fb1712001-10-19 05:35:40 +0000368- The freeze tool has been made more robust, and two new options have
369 been added: -X and -E.
370
Tim Petersabf925f2001-09-28 21:53:42 +0000371Build
372
Barry Warsawf6fb1712001-10-19 05:35:40 +0000373- configure will use CXX in LINKCC if CXX is used to build main() and
374 the system requires to link a C++ main using the C++ compiler.
375
Tim Petersabf925f2001-09-28 21:53:42 +0000376C API
377
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000378- The documentation for the tp_compare slot is updated to require that
379 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
380 not correct. This is not yet enforced but will be enforced in
381 Python 2.3; even later, we may use -2 to indicate errors and +2 for
382 "NotImplemented". Right now, -1 should be used for an error return.
383
Tim Petersd38b1c72001-09-30 05:09:37 +0000384- PyLong_AsLongLong() now accepts int (as well as long) arguments.
385 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
386 as long) arguments.
387
Guido van Rossum3c288632001-10-16 21:13:49 +0000388- PyThread_start_new_thread() now returns a long int giving the thread
389 ID, if one can be calculated; it returns -1 for error, 0 if no
390 thread ID is calculated (this is an incompatible change, but only
391 the thread module used this API). This code has only really been
392 tested on Linux and Windows; other platforms please beware (and
393 report any bugs or strange behavior).
394
Guido van Rossum1c486092001-10-19 02:05:35 +0000395- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
396 input.
397
Tim Petersabf925f2001-09-28 21:53:42 +0000398New platforms
399
400Tests
401
402Windows
403
Tim Peters04cf1d32001-10-09 22:39:40 +0000404- Installer: If you install IDLE, and don't disable file-extension
405 registration, a new "Edit with IDLE" context (right-click) menu entry
406 is created for .py and .pyw files.
407
Tim Peters1ce3cf72001-10-01 17:58:40 +0000408- The signal module now supports SIGBREAK on Windows, thanks to Steven
409 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
410 action remains to call Win32 ExitProcess(). This can be changed via
411 signal.signal(). For example:
412
413 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
414 # (SIGINT) behavior.
415 import signal
416 signal.signal(signal.SIGBREAK,
417 signal.default_int_handler)
418
419 try:
420 while 1:
421 pass
422 except KeyboardInterrupt:
423 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
424 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
425 # program without the possibility for any Python-level cleanup).
426 print "Clean exit"
427
Tim Petersabf925f2001-09-28 21:53:42 +0000428
Tim Petersb07352e2001-09-08 01:25:47 +0000429What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000430Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000431===========================
432
Guido van Rossum808eea72001-09-25 04:15:41 +0000433Type/class unification and new-style classes
434
435- pydoc and inspect are now aware of new-style classes;
436 e.g. help(list) at the interactive prompt now shows proper
437 documentation for all operations on list objects.
438
439- Applications using Jim Fulton's ExtensionClass module can now safely
440 be used with Python 2.2. In particular, Zope 2.4.1 now works with
441 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
442 examples also work again. It is hoped that Gtk and Boost also work
443 with 2.2a4 and beyond. (If you can confirm this, please write
444 webmaster@python.org; if there are still problems, please open a bug
445 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000446
Tim Peters66c1a522001-09-24 21:17:50 +0000447- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
448 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
449 in the constructed property object. fget, fset and fdel weren't
450 discoverable from Python in 2.2a3. __doc__ is new, and allows to
451 associate a docstring with a property.
452
Guido van Rossum808eea72001-09-25 04:15:41 +0000453- Comparison overloading is now more completely implemented. For
454 example, a str subclass instance can properly be compared to a str
455 instance, and it can properly overload comparison. Ditto for most
456 other built-in object types.
457
458- The repr() of new-style classes has changed; instead of <type
459 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
460 *except* for built-in types, which are still rendered as <type
461 'Foo'> (to avoid upsetting existing code that might parse or
462 otherwise rely on repr() of certain type objects).
463
464- The repr() of new-style objects is now always <Foo object at XXX>;
465 previously, it was sometimes <Foo instance at XXX>.
466
467- For new-style classes, what was previously called __getattr__ is now
468 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000469 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000470 one in classic classes is defined which is called only if regular
471 attribute access raises AttributeError; to catch *all* attribute
472 access, you can use __getattribute__ (for new-style classes). If
473 both are defined, __getattribute__ is called first, and if it raises
474 AttributeError, __getattr__ is called.
475
476- The __class__ attribute of new-style objects can be assigned to.
477 The new class must have the same C-level object layout as the old
478 class.
479
480- The builtin file type can be subclassed now. In the usual pattern,
481 "file" is the name of the builtin type, and file() is a new builtin
482 constructor, with the same signature as the builtin open() function.
483 file() is now the preferred way to open a file.
484
485- Previously, __new__ would only see sequential arguments passed to
486 the type in a constructor call; __init__ would see both sequential
487 and keyword arguments. This made no sense whatsoever any more, so
488 now both __new__ and __init__ see all arguments.
489
490- Previously, hash() applied to an instance of a subclass of str or
491 unicode always returned 0. This has been repaired.
492
493- Previously, an operation on an instance of a subclass of an
494 immutable type (int, long, float, complex, tuple, str, unicode),
495 where the subtype didn't override the operation (and so the
496 operation was handled by the builtin type), could return that
497 instance instead a value of the base type. For example, if s was of
498 a str sublass type, s[:] returned s as-is. Now it returns a str
499 with the same value as s.
500
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000501- Provisional support for pickling new-style objects has been added.
502
Guido van Rossum808eea72001-09-25 04:15:41 +0000503Core
504
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000505- file.writelines() now accepts any iterable object producing strings.
506
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000507- PyUnicode_FromEncodedObject() now works very much like
508 PyObject_Str(obj) in that it tries to use __str__/tp_str
509 on the object if the object is not a string or buffer. This
510 makes unicode() behave like str() when applied to non-string/buffer
511 objects.
512
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000513- PyFile_WriteObject now passes Unicode objects to the file's write
514 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000515 of a print statement must support Unicode objects, i.e. they must
516 at least convert them into ASCII strings.
517
Guido van Rossum624c8af2001-09-18 15:21:04 +0000518- Thread scheduling on Solaris should be improved; it is no longer
519 necessary to insert a small sleep at the start of a thread in order
520 to let other runnable threads be scheduled.
521
Tim Petersb07352e2001-09-08 01:25:47 +0000522Library
523
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000524- StringIO.StringIO instances and cStringIO.StringIO instances support
525 read character buffer compatible objects for their .write() methods.
526 These objects are converted to strings and then handled as such
527 by the instances.
528
Barry Warsaw2f600732001-09-24 04:28:10 +0000529- The "email" package has been added. This is basically a port of the
530 mimelib package <http://sf.net/projects/mimelib> with API changes
531 and some implementations updated to use iterators and generators.
532
Tim Peters8a9c2842001-09-22 21:30:22 +0000533- difflib.ndiff() and difflib.Differ.compare() are generators now. This
534 restores the ability of Tools/scripts/ndiff.py to start producing output
535 before the entire comparison is complete.
536
Barry Warsaw58b072d2001-09-22 04:44:21 +0000537- StringIO.StringIO instances and cStringIO.StringIO instances support
538 iteration just like file objects (i.e. their .readline() method is
539 called for each iteration until it returns an empty string).
540
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000541- The codecs module has grown four new helper APIs to access
542 builtin codecs: getencoder(), getdecoder(), getreader(),
543 getwriter().
544
Guido van Rossum624c8af2001-09-18 15:21:04 +0000545- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
546 simplifies writing XML RPC servers.
547
Barry Warsaw647d5e82001-09-28 17:01:02 +0000548- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000549 after interpretation of symbolic links. On non-Unix systems, this
550 is an alias for os.path.abspath().
551
Tim Peters16a77ad2001-09-08 04:00:12 +0000552- operator.indexOf() (PySequence_Index() in the C API) now works with any
553 iterable object.
554
Guido van Rossum624c8af2001-09-18 15:21:04 +0000555- smtplib now supports various authentication and security features of
556 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000557
Guido van Rossum624c8af2001-09-18 15:21:04 +0000558- hmac: a new module implementing keyed hashing for message
559 authentication.
560
561- mimetypes now recognizes more extensions and file types. At the
562 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000563
Guido van Rossum624c8af2001-09-18 15:21:04 +0000564- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000565 Python 2.2 bytecode generation. It has also been promoted from a
566 Tool to a standard library package. (Tools/compiler still exists as
567 a sample driver.)
568
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000569Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000570
Tim Petersb07352e2001-09-08 01:25:47 +0000571Build
572
Guido van Rossum624c8af2001-09-18 15:21:04 +0000573- Large file support (LFS) is now automatic when the platform supports
574 it; no more manual configuration tweaks are needed. On Linux, at
575 least, it's possible to have a system whose C library supports large
576 files but whose kernel doesn't; in this case, large file support is
577 still enabled but doesn't do you any good unless you upgrade your
578 kernel or share your Python executable with another system whose
579 kernel has large file support.
580
581- The configure script now supplies plausible defaults in a
582 cross-compilation environment. This doesn't mean that the supplied
583 values are always correct, or that cross-compilation now works
584 flawlessly -- but it's a first step (and it shuts up most of
585 autoconf's warnings about AC_TRY_RUN).
586
587- The Unix build is now a bit less chatty, courtesy of the parser
588 generator. The build is completely silent (except for errors) when
589 using "make -s", thanks to a -q option to setup.py.
590
Tim Petersb07352e2001-09-08 01:25:47 +0000591C API
592
Guido van Rossum624c8af2001-09-18 15:21:04 +0000593- The "structmember" API now supports some new flag bits to deny read
594 and/or write access to attributes in restricted execution mode.
595
Tim Petersb07352e2001-09-08 01:25:47 +0000596New platforms
597
Guido van Rossum624c8af2001-09-18 15:21:04 +0000598- Compaq's iPAQ handheld, running the "familiar" Linux distribution
599 (http://familiar.handhelds.org).
600
Tim Petersb07352e2001-09-08 01:25:47 +0000601Tests
602
Tim Peters8a9c2842001-09-22 21:30:22 +0000603- The "classic" standard tests, which work by comparing stdout to
604 an expected-output file under Lib/test/output/, no longer stop at
605 the first mismatch. Instead the test is run to completion, and a
606 variant of ndiff-style comparison is used to report all differences.
607 This is much easier to understand than the previous style of reporting.
608
609- The unittest-based standard tests now use regrtest's test_main()
610 convention, instead of running as a side-effect of merely being
611 imported. This allows these tests to be run in more natural and
612 flexible ways as unittests, outside the regrtest framework.
613
614- regrtest.py is much better integrated with unittest and doctest now,
615 especially in regard to reporting errors.
616
Tim Petersb07352e2001-09-08 01:25:47 +0000617Windows
618
Guido van Rossum624c8af2001-09-18 15:21:04 +0000619- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000620 that support it (NTFS under Windows 2000). See "What's New in
621 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000622
Tim Petersb07352e2001-09-08 01:25:47 +0000623
Tim Petersedc99312001-08-22 21:36:50 +0000624What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000625Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000626===========================
627
628Core
629
Tim Peters9fffa3e2001-09-04 05:14:19 +0000630- Conversion of long to float now raises OverflowError if the long is too
631 big to represent as a C double.
632
Tim Peters32f453e2001-09-03 08:35:41 +0000633- The 3-argument builtin pow() no longer allows a third non-None argument
634 if either of the first two arguments is a float, or if both are of
635 integer types and the second argument is negative (in which latter case
636 the arguments are converted to float, so this is really the same
637 restriction).
638
Tim Peters5d2b77c2001-09-03 05:47:38 +0000639- The builtin dir() now returns more information, and sometimes much
640 more, generally naming all attributes of an object, and all attributes
641 reachable from the object via its class, and from its class's base
642 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
643 an empty list. In 2.2a3,
644
645 >>> dir([])
646 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
647 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
648 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
649 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
650 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
651 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
652 'reverse', 'sort']
653
654 dir(module) continues to return only the module's attributes, though.
655
Tim Petersbdee63f2001-09-02 03:40:59 +0000656- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000657 than raising OverflowError. This is a partial implementation of PEP
658 237. You can use -Wdefault::OverflowWarning to enable a warning for
659 this situation, and -Werror::OverflowWarning to revert to the old
660 OverflowError exception.
661
Guido van Rossum61c345f2001-09-04 03:26:15 +0000662- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000663 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000664 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
665 -Qold, meaning the / operator has its classic meaning and no
666 warnings are issued. Using -Qwarn issues a run-time warning about
667 all uses of classic division for int and long arguments; -Qwarnall
668 also warns about classic division for float and complex arguments
669 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
670 new division by default, but only in the __main__ module. You can
671 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
672 __main__ module new division, and warns about classic division
673 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000674
Tim Petersbdee63f2001-09-02 03:40:59 +0000675- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000676 long, float, str, unicode, and tuple. (The types complex, list and
677 dictionary can also be subclassed; this was introduced earlier.)
678 Note that restrictions apply when subclassing immutable built-in
679 types: you can only affect the value of the instance by overloading
680 __new__. You can add mutable attributes, and the subclass instances
681 will have a __dict__ attribute, but you cannot change the "value"
682 (as implemented by the base class) of an immutable subclass instance
683 once it is created.
684
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000685- The dictionary constructor now takes an optional argument, a
686 mapping-like object, and initializes the dictionary from its
687 (key, value) pairs.
688
Tim Petersbdee63f2001-09-02 03:40:59 +0000689- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000690 "cooperative super calls" in a multiple inheritance setting. For an
691 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
692
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000693- A new built-in type, property, has been added. This enables the
694 creation of "properties". These are attributes implemented by
695 getter and setter functions (or only one of these for read-only or
696 write-only attributes), without the need to override __getattr__.
697 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000698
Tim Petersbdee63f2001-09-02 03:40:59 +0000699- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000700 liberalized, to allow leading zeroes. Examples of literals now
701 legal that were SyntaxErrors before:
702
703 00.0 0e3 0100j 07.5 00000000000000000008.
704
Tim Petersbdee63f2001-09-02 03:40:59 +0000705- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000706 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
707
Tim Petersedc99312001-08-22 21:36:50 +0000708Library
709
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000710- telnetlib includes symbolic names for the options, and support for
711 setting an option negotiation callback.
712
Tim Petersa40c7932001-09-05 22:36:56 +0000713- The new C standard no longer requires that math libraries set errno to
714 ERANGE on overflow. For platform libraries that exploit this new
715 freedom, Python's overflow-checking was wholly broken. A new overflow-
716 checking scheme attempts to repair that, but may not be reliable on all
717 platforms (C doesn't seem to provide anything both useful and portable
718 in this area anymore).
719
Martin v. Löwis44f86962001-09-05 13:44:54 +0000720- Asynchronous timeout actions are available through the new class
721 threading.Timer.
722
Tim Peters78526162001-09-05 00:53:45 +0000723- math.log and math.log10 now return sensible results for even huge
724 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
725
Tim Petersbdee63f2001-09-02 03:40:59 +0000726- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000727 currently held. See the docs for the imp module.
728
Tim Petersbdee63f2001-09-02 03:40:59 +0000729- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000730 dumps containing ints written on platforms where Python ints are 8 bytes.
731 When read on a box where Python ints are 4 bytes, such values are
732 converted to Python longs.
733
Tim Petersbdee63f2001-09-02 03:40:59 +0000734- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000735 code objects is no longer allowed. This plugs a security hole.
736
Steve Purcell6091cd62001-09-06 16:05:17 +0000737- unittest.TestResult instances no longer store references to tracebacks
738 generated by test failures. This prevents unexpected dangling references
739 to objects that should be garbage collected between tests.
740
Tim Petersedc99312001-08-22 21:36:50 +0000741Tools
742
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000743- Tools/scripts/fixdiv.py has been added which can be used to fix
744 division operators as per PEP 238.
745
Tim Petersedc99312001-08-22 21:36:50 +0000746Build
747
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000748- If you are an adventurous person using Mac OS X you may want to look at
749 Mac/OSX. There is a Makefile there that will build Python as a real Mac
750 application, which can be used for experimenting with Carbon or Cocoa.
751 Discussion of this on pythonmac-sig, please.
752
Tim Peters7eea37e2001-09-04 22:08:56 +0000753C API
754
755- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000756
Tim Peters9fffa3e2001-09-04 05:14:19 +0000757- Note that PyLong_AsDouble can fail! This has always been true, but no
758 callers checked for it. It's more likely to fail now, because overflow
759 errors are properly detected now. The proper way to check:
760
761 double x = PyLong_AsDouble(some_long_object);
762 if (x == -1.0 && PyErr_Occurred()) {
763 /* The conversion failed. */
764 }
765
Tim Petersbdee63f2001-09-02 03:40:59 +0000766- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000767 compile but will not participate in GC. To upgrade an extension
768 module:
769
770 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000771
Neil Schemenauer4042c692001-08-30 15:38:01 +0000772 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
773 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000774
Neil Schemenauer4042c692001-08-30 15:38:01 +0000775 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
776 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000777
Neil Schemenauer4042c692001-08-30 15:38:01 +0000778 - remove PyGC_HEAD_SIZE from object size calculations
779
780 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
781
Tim Petersbdee63f2001-09-02 03:40:59 +0000782- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000783 These can be used safely to construct string objects from a
784 sprintf-style format string (similar to the format string supported
785 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000786
Tim Petersedc99312001-08-22 21:36:50 +0000787New platforms
788
Tim Petersb7da0902001-09-02 23:01:43 +0000789- Stephen Hansen contributed patches sufficient to get a clean compile
790 under Borland C (Windows), but he reports problems running it and ran
791 out of time to complete the port. Volunteers? Expect a MemoryError
792 when importing the types module; this is probably shallow, and
793 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000794
Tim Petersedc99312001-08-22 21:36:50 +0000795Tests
796
797Windows
798
Tim Peters6e13a562001-09-06 00:32:15 +0000799- Large file support is now enabled on Win32 platforms as well as on
800 Win64. This means that, for example, you can use f.tell() and f.seek()
801 to manipulate files larger than 2 gigabytes (provided you have enough
802 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000803 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
804 filesize limit, and large file support makes no difference there.
805 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
806 NTFS has no practical limit on file size, and files of any size can be
807 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000808
Tim Petersbdee63f2001-09-02 03:40:59 +0000809- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000810 points to command.com (patch from Brian Quinlan).
811
Tim Petersedc99312001-08-22 21:36:50 +0000812
Tim Peters20f51a72001-07-21 02:31:40 +0000813What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000814Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000815===========================
816
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000817Build
818
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000819- Tim Peters developed a brand new Windows installer using Wise 8.1,
820 generously donated to us by Wise Solutions.
821
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000822- configure supports a new option --enable-unicode, with the values
823 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
824 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000825
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000826- A new configure option --enable-framework builds a Mac OS X framework,
827 which "make frameworkinstall" will install. This provides a starting
828 point for more mac-like functionality, join pythonmac-sig@python.org
829 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000830
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000831- The NeXT platform is no longer supported.
832
833- The `new' module is now statically linked.
834
Tim Peters0afb6092001-08-15 06:06:44 +0000835Tools
836
837- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000838 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000839 the module docstring for details.
840
Tim Peters20f51a72001-07-21 02:31:40 +0000841Tests
842
Tim Peters5e824c32001-08-12 22:25:01 +0000843- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000844 platforms, allowing to give clearer test result output. regrtest
845 also has optional --use/-u switch to run normally disabled tests
846 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000847
Tim Peters20f51a72001-07-21 02:31:40 +0000848- Several new tests in the standard test suite, with special thanks to
849 Nick Mathewson.
850
851Core
852
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000853- The floor division operator // has been added as outlined in PEP
854 238. The / operator still provides classic division (and will until
855 Python 3.0) unless "from __future__ import division" is included, in
856 which case the / operator will provide true division. The operator
857 module provides truediv() and floordiv() functions. Augmented
858 assignment variants are included, as are the equivalent overloadable
859 methods and C API methods. See the PEP for a full discussion:
860 <http://python.sf.net/peps/pep-0238.html>
861
Tim Peters6cd6a822001-08-17 22:11:27 +0000862- Future statements are now effective in simulated interactive shells
863 (like IDLE). This should "just work" by magic, but read Michael
864 Hudson's "Future statements in simulated shells" PEP 264 for full
865 details: <http://python.sf.net/peps/pep-0264.html>.
866
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000867- The type/class unification (PEP 252-253) was integrated into the
868 trunk and is not so tentative any more (the exact specification of
869 some features is still tentative). A lot of work has done on fixing
870 bugs and adding robustness and features (performance still has to
871 come a long way).
872
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000873- Warnings about a mismatch in the Python API during extension import
874 now use the Python warning framework (which makes it possible to
875 write filters for these warnings).
876
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000877- A function's __dict__ (aka func_dict) will now always be a
878 dictionary. It used to be possible to delete it or set it to None,
879 but now both actions raise TypeErrors. It is still legal to set it
880 to a dictionary object. Getting func.__dict__ before any attributes
881 have been assigned now returns an empty dictionary instead of None.
882
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000883- A new command line option, -E, was added which disables the use of
884 all environment variables, or at least those that are specifically
885 significant to Python. Usually those have a name starting with
886 "PYTHON". This was used to fix a problem where the tests fail if
887 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
888 older distribution.
889
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000890Library
891
Tim Peters5e824c32001-08-12 22:25:01 +0000892- New class Differ and new functions ndiff() and restore() in difflib.py.
893 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000894 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000895
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000896- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
897 value using the minimal quoting required for the value; more
898 reliable than using xml.sax.saxutils.escape() for attribute values.
899
900- Readline completion support for cmd.Cmd was added.
901
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000902- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
903
904- Added function threading.BoundedSemaphore()
905
906- Added Ka-Ping Yee's cgitb.py module.
907
908- The `new' module now exposes the CO_xxx flags.
909
Martin v. Löwis560da622001-11-24 09:24:51 +0000910- The gc module offers the get_referents function.
911
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000912New platforms
913
914C API
915
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000916- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
917 which provide a cross-platform implementations for the
918 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
919 the standard sprintf() and vsprintf() C lib APIs, these versions
920 apply bounds checking on the used buffer which enhances protection
921 against buffer overruns.
922
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000923- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000924 and extensions using different Unicode widths is rendered next to
925 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000926 will result in an ImportError. Unicode extensions writers must make
927 sure to check the Unicode width compatibility in their extensions by
928 using at least one of the mangled Unicode APIs in the extension.
929
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000930- Two new flags METH_NOARGS and METH_O are available in method definition
931 tables to simplify implementation of methods with no arguments and a
932 single untyped argument. Calling such methods is more efficient than
933 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
934 deprecated.
935
Tim Petersc1731372001-08-04 08:12:36 +0000936Windows
937
938- "import module" now compiles module.pyw if it exists and nothing else
939 relevant is found.
940
Tim Peters20f51a72001-07-21 02:31:40 +0000941
Guido van Rossum55a78992001-07-17 17:22:32 +0000942What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000943Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000944===========================
945
946Core
Tim Petersa814db52001-05-14 07:05:58 +0000947
Tim Peters6d6c1a32001-08-02 04:15:00 +0000948- TENTATIVELY, a large amount of code implementing much of what's
949 described in PEP 252 (Making Types Look More Like Classes) and PEP
950 253 (Subtyping Built-in Types) was added. This will be released
951 with Python 2.2a1. Documentation will be provided separately
952 through http://www.python.org/2.2/. The purpose of releasing this
953 with Python 2.2a1 is to test backwards compatibility. It is
954 possible, though not likely, that a decision is made not to release
955 this code as part of 2.2 final, if any serious backwards
956 incompapatibilities are found during alpha testing that cannot be
957 repaired.
958
Guido van Rossum55a78992001-07-17 17:22:32 +0000959- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000960 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000961 more 'yield' statements. See PEP 255. Since this adds a new
962 keyword to the language, this feature must be enabled by including a
963 future statement: "from __future__ import generators" (see PEP 236).
964 Generators will become a standard feature in a future release
965 (probably 2.3). Without this future statement, 'yield' remains an
966 ordinary identifier, but a warning is issued each time it is used.
967 (These warnings currently don't conform to the warnings framework of
968 PEP 230; we intend to fix this in 2.2a2.)
969
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000970- The UTF-16 codec was modified to be more RFC compliant. It will now
971 only remove BOM characters at the start of the string and then
972 only if running in native mode (UTF-16-LE and -BE won't remove a
973 leading BMO character).
974
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000975- Strings now have a new method .decode() to complement the already
976 existing .encode() method. These two methods provide direct access
977 to the corresponding decoders and encoders of the registered codecs.
978
979 To enhance the usability of the .encode() method, the special
980 casing of Unicode object return values was dropped (Unicode objects
981 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000982
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000983 Both methods will now return whatever the codec in charge of the
984 requested encoding returns as object, e.g. Unicode codecs will
985 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
986 will return u"äöü"). This enables codec writer to create codecs
987 for various simple to use conversions.
988
989 New codecs were added to demonstrate these new features (the .encode()
990 and .decode() columns indicate the type of the returned objects):
991
992 Name | .encode() | .decode() | Description
993 ----------------------------------------------------------------------
994 uu | string | string | UU codec (e.g. for email)
995 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000996 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000997 zlib | string | string | zlib compression
998 hex | string | string | 2-byte hex codec
999 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1000
Mark Hammond2a0af792001-05-14 03:09:36 +00001001- Some operating systems now support the concept of a default Unicode
1002 encoding for file system operations. Notably, Windows supports 'mbcs'
1003 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001004 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001005 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001006
1007 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001008 functions that return filenames (such as os.listdir()) to return Python
1009 string objects pre-encoded using the default file system encoding for
1010 the platform. As this encoding is likely to be different from Python's
1011 default encoding, converting this name to a Unicode object before passing
1012 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001013 would attempt to use its default encoding (generally ASCII) rather than
1014 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001015
Tim Petersa814db52001-05-14 07:05:58 +00001016 In general, this change simply removes surprises when working with
1017 Unicode and the file system, making these operations work as you expect,
1018 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001019 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001020
Tim Peters61dff2b2001-05-08 15:43:37 +00001021- Float (and complex) literals in source code were evaluated to full
1022 precision only when running from a .py file; the same code loaded from a
1023 .pyc (or .pyo) file could suffer numeric differences starting at about the
1024 12th significant decimal digit. For example, on a machine with IEEE-754
1025 floating arithmetic,
1026
1027 x = 9007199254740992.0
1028 print long(x)
1029
1030 printed 9007199254740992 if run directly from .py, but 9007199254740000
1031 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1032 str(float) instead of repr(float) when building code objects. marshal
1033 now uses repr(float) instead, which should reproduce floats to full
1034 machine precision (assuming the platform C float<->string I/O conversion
1035 functions are of good quality).
1036
1037 This may cause floating-point results to change in some cases, and
1038 usually for the better, but may also cause numerically unstable
1039 algorithms to break.
1040
Tim Peters2f228e72001-05-13 00:19:31 +00001041- The implementation of dicts suffers fewer collisions, which has speed
1042 benefits. However, the order in which dict entries appear in dict.keys(),
1043 dict.values() and dict.items() may differ from previous releases for a
1044 given dict. Nothing is defined about this order, so no program should
1045 rely on it. Nevertheless, it's easy to write test cases that rely on the
1046 order by accident, typically because of printing the str() or repr() of a
1047 dict to an "expected results" file. See Lib/test/test_support.py's new
1048 sortdict(dict) function for a simple way to display a dict in sorted
1049 order.
1050
Tim Peters7a3bfc32001-06-12 01:22:22 +00001051- Many other small changes to dicts were made, resulting in faster
1052 operation along the most common code paths.
1053
Guido van Rossum10315822001-05-01 20:54:30 +00001054- Dictionary objects now support the "in" operator: "x in dict" means
1055 the same as dict.has_key(x).
1056
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001057- The update() method of dictionaries now accepts generic mapping
1058 objects. Specifically the argument object must support the .keys()
1059 and __getitem__() methods. This allows you to say, for example,
1060 {}.update(UserDict())
1061
Guido van Rossum10315822001-05-01 20:54:30 +00001062- Iterators were added; this is a generalized way of providing values
1063 to a for loop. See PEP 234. There's a new built-in function iter()
1064 to return an iterator. There's a new protocol to get the next value
1065 from an iterator using the next() method (in Python) or the
1066 tp_iternext slot (in C). There's a new protocol to get iterators
1067 using the __iter__() method (in Python) or the tp_iter slot (in C).
1068 Iterating (i.e. a for loop) over a dictionary generates its keys.
1069 Iterating over a file generates its lines.
1070
Tim Petersf553f892001-05-01 20:45:31 +00001071- The following functions were generalized to work nicely with iterator
1072 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001073 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001074 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1075 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001076 join() method of strings
1077 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001078 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1079 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001080 right-hand side of assignment statements with multiple targets, such as
1081 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001082
Tim Petersd85e1022001-05-11 21:51:48 +00001083- Accessing module attributes is significantly faster (for example,
1084 random.random or os.path or yourPythonModule.yourAttribute).
1085
Tim Peterse63415e2001-05-08 04:38:29 +00001086- Comparing dictionary objects via == and != is faster, and now works even
1087 if the keys and values don't support comparisons other than ==.
1088
Tim Peters95bf9392001-05-10 08:32:44 +00001089- Comparing dictionaries in ways other than == and != is slower: there were
1090 insecurities in the dict comparison implementation that could cause Python
1091 to crash if the element comparison routines for the dict keys and/or
1092 values mutated the dicts. Making the code bulletproof slowed it down.
1093
Tim Peterseb28ef22001-06-02 05:27:19 +00001094- Collisions in dicts are resolved via a new approach, which can help
1095 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001096 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001097 faster now. Thanks to Christian Tismer for pointing out the cause and
1098 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001099
Tim Peters52e155e2001-06-16 05:42:57 +00001100- repr() is much faster for large containers (dict, list, tuple).
1101
1102
Tim Petersa814db52001-05-14 07:05:58 +00001103Library
1104
Fred Drake960fdf92001-07-20 18:38:26 +00001105- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1106 were added to the string module. These a locale-indenpendent
1107 constants, unlike letters, lowercase, and uppercase. These are now
1108 use in appropriate locations in the standard library.
1109
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001110- The flags used in dlopen calls can now be configured using
1111 sys.setdlopenflags and queried using sys.getdlopenflags.
1112
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001113- Fredrik Lundh's xmlrpclib is now a standard library module. This
1114 provides full client-side XML-RPC support. In addition,
1115 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1116 one asyncore-based). Thanks to Eric Raymond for the documentation.
1117
Guido van Rossum643d3912001-07-05 14:46:25 +00001118- The xrange() object is simplified: it no longer supports slicing,
1119 repetition, comparisons, efficient 'in' checking, the tolist()
1120 method, or the start, stop and step attributes. See PEP 260.
1121
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001122- A new function fnmatch.filter to filter lists of file names was added.
1123
Barry Warsawffd674d2001-05-22 16:00:10 +00001124- calendar.py uses month and day names based on the current locale.
1125
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001126- strop is now *really* obsolete (this was announced before with 1.6),
1127 and issues DeprecationWarning when used (except for the four items
1128 that are still imported into string.py).
1129
Tim Petersa814db52001-05-14 07:05:58 +00001130- Cookie.py now sorts key+value pairs by key in output strings.
1131
1132- pprint.isrecursive(object) didn't correctly identify recursive objects.
1133 Now it does.
1134
Tim Peters95b3f782001-05-14 18:39:41 +00001135- pprint functions now much faster for large containers (tuple, list, dict).
1136
Tim Peters7b9542a2001-06-10 23:40:19 +00001137- New 'q' and 'Q' format codes in the struct module, corresponding to C
1138 types "long long" and "unsigned long long" (on Windows, __int64). In
1139 native mode, these can be used only when the platform C compiler supports
1140 these types (when HAVE_LONG_LONG is #define'd by the Python config
1141 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001142 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1143 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001144
Guido van Rossum83213cc2001-06-12 16:48:52 +00001145- The site module installs a new built-in function 'help' that invokes
1146 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1147 it displays a message reminding the user to use 'help()' or
1148 'help(object)'.
1149
Tim Petersa814db52001-05-14 07:05:58 +00001150Tests
1151
1152- New test_mutants.py runs dict comparisons where the key and value
1153 comparison operators mutute the dicts randomly during comparison. This
1154 rapidly causes Python to crash under earlier releases (not for the faint
1155 of heart: it can also cause Win9x to freeze or reboot!).
1156
1157- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001158 pprint.isreadable() return sensible results. Also verifies that simple
1159 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001160
Tim Peters4324aa32001-05-28 22:30:08 +00001161C API
1162
1163- Removed the unused last_is_sticky argument from the internal
1164 _PyTuple_Resize(). If this affects you, you were cheating.
1165
1166
Guido van Rossum55a78992001-07-17 17:22:32 +00001167======================================================================
1168
1169
Guido van Rossumffe13be2001-04-16 18:46:45 +00001170What's New in Python 2.1 (final)?
1171=================================
1172
1173We only changed a few things since the last release candidate, all in
1174Python library code:
1175
1176- A bug in the locale module was fixed that affected locales which
1177 define no grouping for numeric formatting.
1178
1179- A few bugs in the weakref module's implementations of weak
1180 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1181 and the test suite was updated to check for these bugs.
1182
1183- An old bug in the os.path.walk() function (introduced in Python
1184 2.0!) was fixed: a non-existent file would cause an exception
1185 instead of being ignored.
1186
1187- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1188 PyChecker.
1189
1190
Guido van Rossum5b08f132001-04-16 02:05:23 +00001191What's New in Python 2.1c2?
1192===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001193
Guido van Rossum5b08f132001-04-16 02:05:23 +00001194A flurry of small changes, and one showstopper fixed in the nick of
1195time made it necessary to release another release candidate. The list
1196here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001197
Guido van Rossum5b08f132001-04-16 02:05:23 +00001198Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001199
Guido van Rossum5b08f132001-04-16 02:05:23 +00001200- Tim discovered a nasty bug in the dictionary code, caused by
1201 PyDict_Next() calling dict_resize(), and the GC code's use of
1202 PyDict_Next() violating an assumption in dict_items(). This was
1203 fixed with considerable amounts of band-aid, but the net effect is a
1204 saner and more robust implementation.
1205
1206- Made a bunch of symbols static that were accidentally global.
1207
1208Build and Ports
1209
1210- The setup.py script didn't check for a new enough version of zlib
1211 (1.1.3 is needed). Now it does.
1212
1213- Changed "make clean" target to also remove shared libraries.
1214
1215- Added a more general warning about the SGI Irix optimizer to README.
1216
1217Library
1218
1219- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1220 omitted the slash between host and file.html.
1221
1222- The mailbox module's _Mailbox class contained a completely broken
1223 and undocumented seek() method. Ripped it out.
1224
1225- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1226 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1227
1228- Fixed a few last-minute bugs in unittest.
1229
1230Extensions
1231
1232- Reverted the patch to the OpenSSL code in socketmodule.c to support
1233 RAND_status() and the EGD, and the subsequent patch that tried to
1234 fix it for pre-0.9.5 versions; the problem with the patch is that on
1235 some systems it issues a warning whenever socket is imported, and
1236 that's unacceptable.
1237
1238Tests
1239
1240- Fixed the pickle tests to work with "import test.test_pickle".
1241
1242- Tweaked test_locale.py to actually run the test Windows.
1243
1244- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1245 not "wb" (which is not a valid mode at all).
1246
1247- Fix pstats browser crashes. Import readline if it exists to make
1248 the user interface nicer.
1249
1250- Add "import thread" to the top of test modules that import the
1251 threading module (test_asynchat and test_threadedtempfile). This
1252 prevents test failures caused by a broken threading module resulting
1253 from a previously caught failed import.
1254
1255- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1256 needed on some platforms (e.g. Solaris 8) when the tests are run
1257 twice in succession.
1258
1259- Skip rather than fail test_sunaudiodev if no audio device is found.
1260
1261
1262What's New in Python 2.1c1?
1263===========================
1264
1265This list was significantly updated when 2.1c2 was released; the 2.1c1
1266release didn't mention most changes that were actually part of 2.1c1:
1267
1268Legal
1269
1270- Copyright was assigned to the Python Software Foundation (PSF) and a
1271 PSF license (very similar to the CNRI license) was added.
1272
1273- The CNRI copyright notice was updated to include 2001.
1274
1275Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001276
Guido van Rossumc9932722001-04-12 02:31:27 +00001277- After a public outcry, assignment to __debug__ is no longer illegal;
1278 instead, a warning is issued. It will become illegal in 2.2.
1279
Guido van Rossum5b08f132001-04-16 02:05:23 +00001280- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1281 "%#x" now always prepends "0x", even if the value is zero.
1282
1283- Fixed some nits in the bytecode compiler.
1284
1285- Fixed core dumps when calling certain kinds of non-functions.
1286
1287- Fixed various core dumps caused by reference count bugs.
1288
1289Build and Ports
1290
1291- Use INSTALL_SCRIPT to install script files.
1292
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001293- New port: SCO Unixware 7, by Billy G. Allie.
1294
Guido van Rossum5b08f132001-04-16 02:05:23 +00001295- Updated RISCOS port.
1296
1297- Updated BeOS port and notes.
1298
1299- Various other porting problems resolved.
1300
1301Library
1302
1303- The TERMIOS and SOCKET modules are now truly obsolete and
1304 unnecessary. Their symbols are incorporated in the termios and
1305 socket modules.
1306
1307- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1308 better tests for pickling.
1309
1310- threading: make Condition.wait() robust against KeyboardInterrupt.
1311
1312- zipfile: add support to zipfile to support opening an archive
1313 represented by an open file rather than a file name. Fix bug where
1314 the archive was not properly closed. Fixed a bug in this bugfix
1315 where flush() was called for a read-only file.
1316
1317- imputil: added an uninstall() method to the ImportManager.
1318
1319- Canvas: fixed bugs in lower() and tkraise() methods.
1320
1321- SocketServer: API change (added overridable close_request() method)
1322 so that the TCP server can explicitly close the request.
1323
1324- pstats: Eric Raymond added a simple interactive statistics browser,
1325 invoked when the module is run as a script.
1326
1327- locale: fixed a problem in format().
1328
1329- webbrowser: made it work when the BROWSER environment variable has a
1330 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1331 KDE 2. Fixed some other nits.
1332
1333- unittest: changes to allow using a different exception than
1334 AssertionError, and added a few more function aliases. Some other
1335 small changes.
1336
1337- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1338
1339- asynchat: fixed a critical bug in asynchat that slipped through the
1340 2.1b2 release. Fixed another rare bug.
1341
1342- Fix some unqualified except: clauses (always a bad code example).
1343
1344XML
1345
1346- pyexpat: new API get_version_string().
1347
1348- Fixed some minidom bugs.
1349
1350Extensions
1351
1352- Fixed a core dump in _weakref. Removed the weakref.mapping()
1353 function (it adds nothing to the API).
1354
1355- Rationalized the use of header files in the readline module, to make
1356 it compile (albeit with some warnings) with the very recent readline
1357 4.2, without breaking for earlier versions.
1358
1359- Hopefully fixed a buffering problem in linuxaudiodev.
1360
1361- Attempted a fix to make the OpenSSL support in the socket module
1362 work again with pre-0.9.5 versions of OpenSSL.
1363
1364Tests
1365
1366- Added a test case for asynchat and asyncore.
1367
1368- Removed coupling between tests where one test failing could break
1369 another.
1370
1371Tools
1372
1373- Ping added an interactive help browser to pydoc, fixed some nits
1374 in the rest of the pydoc code, and added some features to his
1375 inspect module.
1376
1377- An updated python-mode.el version 4.1 which integrates Ken
1378 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1379 much nicer in XEmacs and Emacs. When stepping through your program
1380 with pdb, in either the shell window or the *Python* window, the
1381 source file and line will be tracked by an arrow. Very cool!
1382
1383- IDLE: syntax warnings in interactive mode are changed into errors.
1384
1385- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001386 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001387
1388- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001389
Barry Warsaw11e89c72001-04-11 20:37:57 +00001390
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001391What's New in Python 2.1 beta 2?
1392================================
1393
Guido van Rossum053ae352001-03-22 14:17:21 +00001394(Unlisted are many fixed bugs, more documentation, etc.)
1395
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001396Core language, builtins, and interpreter
1397
Guido van Rossum053ae352001-03-22 14:17:21 +00001398- The nested scopes work (enabled by "from __future__ import
1399 nested_scopes") is completed; in particular, the future now extends
1400 into code executed through exec, eval() and execfile(), and into the
1401 interactive interpreter.
1402
1403- When calling a base class method (e.g. BaseClass.__init__(self)),
1404 this is now allowed even if self is not strictly spoken a class
1405 instance (e.g. when using metaclasses or the Don Beaudry hook).
1406
1407- Slice objects are now comparable but not hashable; this prevents
1408 dict[:] from being accepted but meaningless.
1409
1410- Complex division is now calculated using less braindead algorithms.
1411 This doesn't change semantics except it's more likely to give useful
1412 results in extreme cases. Complex repr() now uses full precision
1413 like float repr().
1414
1415- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1416
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001417- It is illegal to assign to the name __debug__, which is set when the
1418 interpreter starts. It is effectively a compile-time constant.
1419
1420- A warning will be issued if a global statement for a variable
1421 follows a use or assignment of that variable.
1422
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001423Standard library
1424
Guido van Rossum053ae352001-03-22 14:17:21 +00001425- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1426 inspired by JUnit), is now part of the standard library. You now
1427 have a choice of two testing frameworks: unittest requires you to
1428 write testcases as separate code, doctest gathers them from
1429 docstrings. Both approaches have their advantages and
1430 disadvantages.
1431
1432- A new module Tix was added, which wraps the Tix extension library
1433 for Tk. With that module, it is not necessary to statically link
1434 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1435 require" command. See Demo/tix/.
1436
1437- tzparse.py is now obsolete.
1438
1439- In gzip.py, the seek() and tell() methods are removed -- they were
1440 non-functional anyway, and it's better if callers can test for their
1441 existence with hasattr().
1442
1443Python/C API
1444
1445- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1446 that's already in the dictionary during a PyDict_Next() iteration.
1447 This used to fail occasionally when a dictionary resize operation
1448 could be triggered that would rehash all the keys. All other
1449 modifications to the dictionary are still off-limits during a
1450 PyDict_Next() iteration!
1451
1452- New extended APIs related to passing compiler variables around.
1453
1454- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1455 implement isinstance() and issubclass().
1456
1457- Py_BuildValue() now has a "D" conversion to create a Python complex
1458 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001459
Fred Drake4e262a92001-03-22 18:26:47 +00001460- Extensions types which support weak references must now set the
1461 field allocated for the weak reference machinery to NULL themselves;
1462 this is done to avoid the cost of checking each object for having a
1463 weakly referencable type in PyObject_INIT(), since most types are
1464 not weakly referencable.
1465
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001466- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1467 free variables and cell variables to and from the frame's f_locals.
1468
1469- Variants of several functions defined in pythonrun.h have been added
1470 to support the nested_scopes future statement. The variants all end
1471 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1472 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1473 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001474 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001475
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001476Distutils
1477
1478- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1479 into the release tree.
1480
Tim Peters0e57abf2001-05-02 07:39:38 +00001481- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001482 (an uninstaller, more customization of the installer's display)
1483
1484- from Jack Jansen: added Mac-specific code to generate a dialog for
1485 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001486 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001487 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001488
1489- added 'platforms' and 'keywords' to the set of metadata that can be
1490 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001491
1492- applied patches from Jason Tishler to make the compiler class work with
1493 Cygwin.
1494
1495
Tim Peters2fe289a2001-03-01 22:19:38 +00001496What's New in Python 2.1 beta 1?
1497================================
Tim Petersd66595f2001-02-04 03:09:53 +00001498
1499Core language, builtins, and interpreter
1500
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001501- Following an outcry from the community about the amount of code
1502 broken by the nested scopes feature introduced in 2.1a2, we decided
1503 to make this feature optional, and to wait until Python 2.2 (or at
1504 least 6 months) to make it standard. The option can be enabled on a
1505 per-module basis by adding "from __future__ import nested_scopes" at
1506 the beginning of a module (before any other statements, but after
1507 comments and an optional docstring). See PEP 236 (Back to the
1508 __future__) for a description of the __future__ statement. PEP 227
1509 (Statically Nested Scopes) has been updated to reflect this change,
1510 and to clarify the semantics in a number of endcases.
1511
1512- The nested scopes code, when enabled, has been hardened, and most
1513 bugs and memory leaks in it have been fixed.
1514
1515- Compile-time warnings are now generated for a number of conditions
1516 that will break or change in meaning when nested scopes are enabled:
1517
1518 - Using "from...import *" or "exec" without in-clause in a function
1519 scope that also defines a lambda or nested function with one or
1520 more free (non-local) variables. The presence of the import* or
1521 bare exec makes it impossible for the compiler to determine the
1522 exact set of local variables in the outer scope, which makes it
1523 impossible to determine the bindings for free variables in the
1524 inner scope. To avoid the warning about import *, change it into
1525 an import of explicitly name object, or move the import* statement
1526 to the global scope; to avoid the warning about bare exec, use
1527 exec...in... (a good idea anyway -- there's a possibility that
1528 bare exec will be deprecated in the future).
1529
1530 - Use of a global variable in a nested scope with the same name as a
1531 local variable in a surrounding scope. This will change in
1532 meaning with nested scopes: the name in the inner scope will
1533 reference the variable in the outer scope rather than the global
1534 of the same name. To avoid the warning, either rename the outer
1535 variable, or use a global statement in the inner function.
1536
Neil Schemenauera35c6882001-02-27 04:45:05 +00001537- An optional object allocator has been included. This allocator is
1538 optimized for Python objects and should be faster and use less memory
1539 than the standard system allocator. It is not enabled by default
1540 because of possible thread safety problems. The allocator is only
1541 protected by the Python interpreter lock and it is possible that some
1542 extension modules require a thread safe allocator. The object
1543 allocator can be enabled by providing the "--with-pymalloc" option to
1544 configure.
1545
Tim Petersd66595f2001-02-04 03:09:53 +00001546Standard library
1547
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001548- pyexpat now detects the expat version if expat.h defines it. A
1549 number of additional handlers are provided, which are only available
1550 since expat 1.95. In addition, the methods SetParamEntityParsing and
1551 GetInputContext of Parser objects are available with 1.95.x
1552 only. Parser objects now provide the ordered_attributes and
1553 specified_attributes attributes. A new module expat.model was added,
1554 which offers a number of additional constants if 1.95.x is used.
1555
1556- xml.dom offers the new functions registerDOMImplementation and
1557 getDOMImplementation.
1558
1559- xml.dom.minidom offers a toprettyxml method. A number of DOM
1560 conformance issues have been resolved. In particular, Element now
1561 has an hasAttributes method, and the handling of namespaces was
1562 improved.
1563
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001564- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1565 getting information about live Python code, and pydoc.py, a module
1566 for interactively converting docstrings to HTML or text.
1567 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001568 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001569 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1570 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001571
Tim Peters1eff7962001-03-01 02:31:33 +00001572- New library module difflib.py, primarily packaging the SequenceMatcher
1573 class at the heart of the popular ndiff.py file-comparison tool.
1574
1575- doctest.py (a framework for verifying Python code examples in docstrings)
1576 is now part of the std library.
1577
Tim Petersd66595f2001-02-04 03:09:53 +00001578Windows changes
1579
Guido van Rossume3955a82001-03-02 14:05:59 +00001580- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1581 small GUI that lets you browse the module docstrings using your
1582 default web browser.
1583
Tim Peters1eff7962001-03-01 02:31:33 +00001584- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1585 Platforms) is implemented. See
1586
1587 http://python.sourceforge.net/peps/pep-0235.html
1588
1589 for full details, especially the "Current Lower-Left Semantics" section.
1590 The new Windows import rules are simpler than before:
1591
1592 A. If the PYTHONCASEOK environment variable exists, same as
1593 before: silently accept the first case-insensitive match of any
1594 kind; raise ImportError if none found.
1595
1596 B. Else search sys.path for the first case-sensitive match; raise
1597 ImportError if none found.
1598
1599 The same rules have been implented on other platforms with case-
1600 insensitive but case-preserving filesystems too (including Cygwin, and
1601 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001602
Tim Peters25a9ce32001-02-19 07:06:36 +00001603- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1604 what it's supposed to do (and does do under NT and 2000) via direct
1605 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001606 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001607 all Win9x systems before.
1608
Tim Peters1eff7962001-03-01 02:31:33 +00001609- Build: Subproject _test (effectively) renamed to _testcapi.
1610
Tim Peters2fe289a2001-03-01 22:19:38 +00001611New platforms
1612
1613- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1614 Thanks to Steven Majewski!
1615
1616- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1617 Tishler!
1618
Guido van Rossum9089b272001-03-02 06:49:50 +00001619- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1620 Schwertberger! See RISCOS/README for more information -- it seems
1621 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001622 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001623
Tim Peters25a9ce32001-02-19 07:06:36 +00001624
Tim Petersd7b5e882001-01-25 03:36:26 +00001625What's New in Python 2.1 alpha 2?
1626=================================
Tim Peters40ead762001-01-27 05:35:26 +00001627
Tim Petersd7b5e882001-01-25 03:36:26 +00001628Core language, builtins, and interpreter
1629
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001630- Scopes nest. If a name is used in a function or class, but is not
1631 local, the definition in the nearest enclosing function scope will
1632 be used. One consequence of this change is that lambda statements
1633 could reference variables in the namespaces where the lambda is
1634 defined. In some unusual cases, this change will break code.
1635
1636 In all previous version of Python, names were resolved in exactly
1637 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001638 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001639 function A is defined within a function B, the names bound in B are
1640 not visible in A. The new rules make names bound in B visible in A,
1641 unless A contains a name binding that hides the binding in B.
1642
1643 Section 4.1 of the reference manual describes the new scoping rules
1644 in detail. The test script in Lib/test/test_scope.py demonstrates
1645 some of the effects of the change.
1646
1647 The new rules will cause existing code to break if it defines nested
1648 functions where an outer function has local variables with the same
1649 name as globals or builtins used by the inner function. Example:
1650
1651 def munge(str):
1652 def helper(x):
1653 return str(x)
1654 if type(str) != type(''):
1655 str = helper(str)
1656 return str.strip()
1657
1658 Under the old rules, the name str in helper() is bound to the
1659 builtin function str(). Under the new rules, it will be bound to
1660 the argument named str and an error will occur when helper() is
1661 called.
1662
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001663- The compiler will report a SyntaxError if "from ... import *" occurs
1664 in a function or class scope. The language reference has documented
1665 that this case is illegal, but the compiler never checked for it.
1666 The recent introduction of nested scope makes the meaning of this
1667 form of name binding ambiguous. In a future release, the compiler
1668 may allow this form when there is no possibility of ambiguity.
1669
Tim Peters40ead762001-01-27 05:35:26 +00001670- repr(string) is easier to read, now using hex escapes instead of octal,
1671 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1672
1673 >>> "\texample \r\n" + chr(0) + chr(255)
1674 '\texample \r\n\x00\xff' # in 2.1
1675 '\011example \015\012\000\377' # in 2.0
1676
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001677- Functions are now compared and hashed by identity, not by value, since
1678 the func_code attribute is writable.
1679
Fred Drakefb9d7122001-02-01 20:00:40 +00001680- Weak references (PEP 205) have been added. This involves a few
1681 changes in the core, an extension module (_weakref), and a Python
1682 module (weakref). The weakref module is the public interface. It
1683 includes support for "explicit" weak references, proxy objects, and
1684 mappings with weakly held values.
1685
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001686- A 'continue' statement can now appear in a try block within the body
1687 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001688 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001689
Tim Petersd7b5e882001-01-25 03:36:26 +00001690Standard library
1691
Barry Warsaw30dbd142001-01-31 22:14:01 +00001692- mailbox.py now has a new class, PortableUnixMailbox which is
1693 identical to UnixMailbox but uses a more portable scheme for
1694 determining From_ separators. Also, the constructors for all the
1695 classes in this module have a new optional `factory' argument, which
1696 is a callable used when new message classes must be instantiated by
1697 the next() method.
1698
Tim Petersd7b5e882001-01-25 03:36:26 +00001699- random.py is now self-contained, and offers all the functionality of
1700 the now-deprecated whrandom.py. See the docs for details. random.py
1701 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001702 and restoring the internal state of the generator; and jumpahead(n),
1703 for quickly forcing the internal state to be the same as if n calls to
1704 random() had been made. The latter is particularly useful for multi-
1705 threaded programs, creating one instance of the random.Random() class for
1706 each thread, then using .jumpahead() to force each instance to use a
1707 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001708
Tim Peters0de88fc2001-02-01 04:59:18 +00001709- random.py's seed() function is new. For bit-for-bit compatibility with
1710 prior releases, use the whseed function instead. The new seed function
1711 addresses two problems: (1) The old function couldn't produce more than
1712 about 2**24 distinct internal states; the new one about 2**45 (the best
1713 that can be done in the Wichmann-Hill generator). (2) The old function
1714 sometimes produced identical internal states when passed distinct
1715 integers, and there was no simple way to predict when that would happen;
1716 the new one guarantees to produce distinct internal states for all
1717 arguments in [0, 27814431486576L).
1718
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001719- The socket module now supports raw packets on Linux. The socket
1720 family is AF_PACKET.
1721
Tim Peters9ea17ac2001-02-02 05:57:15 +00001722- test_capi.py is a start at running tests of the Python C API. The tests
1723 are implemented by the new Modules/_testmodule.c.
1724
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001725- A new extension module, _symtable, provides provisional access to the
1726 internal symbol table used by the Python compiler. A higher-level
1727 interface will be added on top of _symtable in a future release.
1728
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001729- Removed the obsolete soundex module.
1730
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001731- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1732 the isSameNode method; NamedNodeMap the get method.
1733
1734- xml.sax.expatreader supports the lexical handler property; it
1735 generates comment, startCDATA, and endCDATA events.
1736
Tim Petersee826f82001-01-31 19:39:44 +00001737Windows changes
1738
1739- Build procedure: the zlib project is built in a different way that
1740 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001741 the zlib binary used. See PCbuild\readme.txt for details. Your old
1742 zlib-related directories can be deleted; you'll need to download fresh
1743 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001744
Tim Peters9ea17ac2001-02-02 05:57:15 +00001745- Build: New subproject _test for the benefit of test_capi.py (see above).
1746
Tim Petersb16c56f2001-02-02 21:24:51 +00001747- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1748 interface to some Python compiler internals).
1749
1750- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001751 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001752
Tim Petersa3a3a032000-11-30 05:22:44 +00001753What's New in Python 2.1 alpha 1?
1754=================================
1755
1756Core language, builtins, and interpreter
1757
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001758- There is a new Unicode companion to the PyObject_Str() API
1759 called PyObject_Unicode(). It behaves in the same way as the
1760 former, but assures that the returned value is an Unicode object
1761 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001762
Guido van Rossumf98eda02001-01-17 15:54:45 +00001763- The comparison operators support "rich comparison overloading" (PEP
1764 207). C extension types can provide a rich comparison function in
1765 the new tp_richcompare slot in the type object. The cmp() function
1766 and the C function PyObject_Compare() first try the new rich
1767 comparison operators before trying the old 3-way comparison. There
1768 is also a new C API PyObject_RichCompare() (which also falls back on
1769 the old 3-way comparison, but does not constrain the outcome of the
1770 rich comparison to a Boolean result).
1771
1772 The rich comparison function takes two objects (at least one of
1773 which is guaranteed to have the type that provided the function) and
1774 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1775 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1776 object, which may be NotImplemented (in which case the tp_compare
1777 slot function is used as a fallback, if defined).
1778
1779 Classes can overload individual comparison operators by defining one
1780 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001781 __ge__. There are no explicit "reflected argument" versions of
1782 these; instead, __lt__ and __gt__ are each other's reflection,
1783 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1784 reflection (similar at the C level). No other implications are
1785 made; in particular, Python does not assume that == is the Boolean
1786 inverse of !=, or that < is the Boolean inverse of >=. This makes
1787 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001788
1789 Classes or types that want to implement (in)equality tests but not
1790 the ordering operators (i.e. unordered types) should implement ==
1791 and !=, and raise an error for the ordering operators.
1792
Guido van Rossuma88479f2001-01-18 14:28:08 +00001793 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001794 Boolean; e.g. a matrix type might want to return a matrix of bits
1795 for A < B, giving elementwise comparisons. Such types should ensure
1796 that any interpretation of their value in a Boolean context raises
1797 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1798 at the C level) to always raise an exception.
1799
Guido van Rossuma88479f2001-01-18 14:28:08 +00001800- Complex numbers use rich comparisons to define == and != but raise
1801 an exception for <, <=, > and >=. Unfortunately, this also means
1802 that cmp() of two complex numbers raises an exception when the two
1803 numbers differ. Since it is not mathematically meaningful to compare
1804 complex numbers except for equality, I hope that this doesn't break
1805 too much code.
1806
Tim Peters3389f192001-02-18 08:48:49 +00001807- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001808 not defined by the language, other than that it's arbitrary but
1809 consistent (see the Reference Manual). An implementation detail changed
1810 in 2.1a1 such that None now compares less than any other object. Code
1811 relying on this new behavior (like code that relied on the previous
1812 behavior) does so at its own risk.
1813
Barry Warsaw573b5412001-01-15 20:43:18 +00001814- Functions and methods now support getting and setting arbitrarily
1815 named attributes (PEP 232). Functions have a new __dict__
1816 (a.k.a. func_dict) which hold the function attributes. Methods get
1817 and set attributes on their underlying im_func. It is a TypeError
1818 to set an attribute on a bound method.
1819
Guido van Rossum051e3352001-01-15 19:11:10 +00001820- The xrange() object implementation has been improved so that
1821 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1822 limitation that in this case len(xrange(sys.maxint)) can't be
1823 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1824 work fine as long as the index i doesn't actually reach 2**31.
1825 (Python uses regular ints for sequence and string indices; fixing
1826 that is much more work.)
1827
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001828- Two changes to from...import:
1829
Guido van Rossumba381232001-02-03 15:06:40 +00001830 1) "from M import X" now works even if (after loading module M)
1831 sys.modules['M'] is not a real module; it's basically a getattr()
1832 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001833
1834 2) "from M import *" now looks for M.__all__ to decide which names to
1835 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1836 filters out names starting with '_' as before. Whether or not
1837 __all__ exists, there's no restriction on the type of M.
1838
Guido van Rossumf61f1662001-01-10 20:13:55 +00001839- File objects have a new method, xreadlines(). This is the fastest
1840 way to iterate over all lines in a file:
1841
1842 for line in file.xreadlines():
1843 ...do something to line...
1844
1845 See the xreadlines module (mentioned below) for how to do this for
1846 other file-like objects.
1847
1848- Even if you don't use file.xreadlines(), you may expect a speedup on
1849 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001850 quite a bit in platform-specific ways: on systems (like Linux) that
1851 support flockfile(), getc_unlocked(), and funlockfile(), those are
1852 used by default. On systems (like Windows) without getc_unlocked(),
1853 a complicated (but still thread-safe) method using fgets() is used by
1854 default.
1855
Tim Petersd52269b2001-01-25 06:23:18 +00001856 You can force use of the fgets() method by #define'ing
1857 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001858 getc_unlocked()).
1859
Tim Petersd52269b2001-01-25 06:23:18 +00001860 You can force fgets() not to be used by #define'ing
1861 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001862 test_bufio.py fails -- and let us know if it does!).
1863
1864- In addition, the fileinput module, while still slower than the other
1865 methods on most platforms, has been sped up too, by using
1866 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001867
1868- Support for run-time warnings has been added, including a new
1869 command line option (-W) to specify the disposition of warnings.
1870 See the description of the warnings module below.
1871
1872- Extensive changes have been made to the coercion code. This mostly
1873 affects extension modules (which can now implement mixed-type
1874 numerical operators without having to use coercion), but
1875 occasionally, in boundary cases the coercion semantics have changed
1876 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001877 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001878 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001879 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001880
Guido van Rossumf98eda02001-01-17 15:54:45 +00001881- In connection with the coercion changes, a new built-in singleton
1882 object, NotImplemented is defined. This can be returned for
1883 operations that wish to indicate they are not implemented for a
1884 particular combination of arguments. From C, this is
1885 Py_NotImplemented.
1886
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001887- The interpreter accepts now bytecode files on the command line even
1888 if they do not have a .pyc or .pyo extension. On Linux, after executing
1889
Martin v. Löwise214baa2001-02-04 22:37:56 +00001890import imp,sys,string
1891magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1892reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1893open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001894
1895 any byte code file can be used as an executable (i.e. as an argument
1896 to execve(2)).
1897
Tim Peters9940b802000-12-01 07:59:35 +00001898- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001899 character. In 1.6 and earlier, they never produced a sign,
1900 and raised an error if the value of the long was too large
1901 to fit in a Python int. In 2.0, they produced a sign if and
1902 only if too large to fit in an int. This was inconsistent
1903 across platforms (because the size of an int varies across
1904 platforms), and inconsistent with hex() and oct(). Example:
1905
1906 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001907 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001908 'ffffffbe' # in 2.0 and before, on 32-bit machines
1909 >>> hex(-0x42L)
1910 '-0x42L' # in all versions of Python
1911
Tim Peters9940b802000-12-01 07:59:35 +00001912 The behavior of %d formats for negative Python longs remains
1913 the same as in 2.0 (although in 1.6 and before, they raised
1914 an error if the long didn't fit in a Python int).
1915
1916 %u formats don't make sense for Python longs, but are allowed
1917 and treated the same as %d in 2.1. In 2.0, a negative long
1918 formatted via %u produced a sign if and only if too large to
1919 fit in an int. In 1.6 and earlier, a negative long formatted
1920 via %u raised an error if it was too big to fit in an int.
1921
Guido van Rossum3661d392000-12-12 22:10:31 +00001922- Dictionary objects have an odd new method, popitem(). This removes
1923 an arbitrary item from the dictionary and returns it (in the form of
1924 a (key, value) pair). This can be useful for algorithms that use a
1925 dictionary as a bag of "to do" items and repeatedly need to pick one
1926 item. Such algorithms normally end up running in quadratic time;
1927 using popitem() they can usually be made to run in linear time.
1928
Tim Peters36cdad12000-12-29 02:06:45 +00001929Standard library
1930
Thomas Woutersfe385252001-01-19 23:16:56 +00001931- In the time module, the time argument to the functions strftime,
1932 localtime, gmtime, asctime and ctime is now optional, defaulting to
1933 the current time (in the local timezone).
1934
Guido van Rossumda91f222001-01-15 16:36:08 +00001935- The ftplib module now defaults to passive mode, which is deemed a
1936 more useful default given that clients are often inside firewalls
1937 these days. Note that this could break if ftplib is used to connect
1938 to a *server* that is inside a firewall, from outside; this is
1939 expected to be a very rare situation. To fix that, you can call
1940 ftp.set_pasv(0).
1941
Martin v. Löwis10a27872001-01-13 09:54:41 +00001942- The module site now treats .pth files not only for path configuration,
1943 but also supports extensions to the initialization code: Lines starting
1944 with import are executed.
1945
Guido van Rossumf61f1662001-01-10 20:13:55 +00001946- There's a new module, warnings, which implements a mechanism for
1947 issuing and filtering warnings. There are some new built-in
1948 exceptions that serve as warning categories, and a new command line
1949 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1950 turns warnings into errors). warnings.warn(message[, category])
1951 issues a warning message; this can also be called from C as
1952 PyErr_Warn(category, message).
1953
1954- A new module xreadlines was added. This exports a single factory
1955 function, xreadlines(). The intention is that this code is the
1956 absolutely fastest way to iterate over all lines in an open
1957 file(-like) object:
1958
1959 import xreadlines
1960 for line in xreadlines.xreadlines(file):
1961 ...do something to line...
1962
1963 This is equivalent to the previous the speed record holder using
1964 file.readlines(sizehint). Note that if file is a real file object
1965 (as opposed to a file-like object), this is equivalent:
1966
1967 for line in file.xreadlines():
1968 ...do something to line...
1969
Tim Peters36cdad12000-12-29 02:06:45 +00001970- The bisect module has new functions bisect_left, insort_left,
1971 bisect_right and insort_right. The old names bisect and insort
1972 are now aliases for bisect_right and insort_right. XXX_right
1973 and XXX_left methods differ in what happens when the new element
1974 compares equal to one or more elements already in the list: the
1975 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001976 right. Code that doesn't care where equal elements end up should
1977 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001978
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001979- The new curses.panel module wraps the panel library that forms part
1980 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1981
Guido van Rossumf61f1662001-01-10 20:13:55 +00001982- The SocketServer module now sets the allow_reuse_address flag by
1983 default in the TCPServer class.
1984
1985- A new function, sys._getframe(), returns the stack frame pointer of
1986 the caller. This is intended only as a building block for
1987 higher-level mechanisms such as string interpolation.
1988
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001989- The pyexpat module supports a number of new handlers, which are
1990 available only in expat 1.2. If invocation of a callback fails, it
1991 will report an additional frame in the traceback. Parser objects
1992 participate now in garbage collection. If expat reports an unknown
1993 encoding, pyexpat will try to use a Python codec; that works only
1994 for single-byte charsets. The parser type objects is exposed as
1995 XMLParserObject.
1996
1997- xml.dom now offers standard definitions for symbolic node type and
1998 exception code constants, and a hierarchy of DOM exceptions. minidom
1999 was adjusted to use them.
2000
2001- The conformance of xml.dom.minidom to the DOM specification was
2002 improved. It detects a number of additional error cases; the
2003 previous/next relationship works even when the tree is modified;
2004 Node supports the normalize() method; NamedNodeMap, DocumentType and
2005 DOMImplementation classes were added; Element supports the
2006 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2007 method.
2008
Guido van Rossumf61f1662001-01-10 20:13:55 +00002009Build issues
2010
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002011- For Unix (and Unix-compatible) builds, configuration and building of
2012 extension modules is now greatly automated. Rather than having to
2013 edit the Modules/Setup file to indicate which modules should be
2014 built and where their include files and libraries are, a
2015 distutils-based setup.py script now takes care of building most
2016 extension modules. All extension modules built this way are built
2017 as shared libraries. Only a few modules that must be linked
2018 statically are still listed in the Setup file; you won't need to
2019 edit their configuration.
2020
2021- Python should now build out of the box on Cygwin. If it doesn't,
2022 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002023
2024- Python now always uses its own (renamed) implementation of getopt()
2025 -- there's too much variation among C library getopt()
2026 implementations.
2027
2028- C++ compilers are better supported; the CXX macro is always set to a
2029 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002030
Tim Petersd92dfe02000-12-12 01:18:41 +00002031Windows changes
2032
2033- select module: By default under Windows, a select() call
2034 can specify no more than 64 sockets. Python now boosts
2035 this Microsoft default to 512. If you need even more than
2036 that, see the MS docs (you'll need to #define FD_SETSIZE
2037 and recompile Python from source).
2038
Guido van Rossumf61f1662001-01-10 20:13:55 +00002039- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2040 subdirectory is no more!
2041
Tim Petersa3a3a032000-11-30 05:22:44 +00002042
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002043What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002044=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002045
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002046Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002047changes are in the file HISTORY. If you are making the jump directly
2048from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2049HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002050
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002051Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2052the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2053http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002054
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002055--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002056
2057======================================================================
2058
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002059What's new in 2.0 (since release candidate 1)?
2060==============================================
2061
2062Standard library
2063
2064- The copy_reg module was modified to clarify its intended use: to
2065 register pickle support for extension types, not for classes.
2066 pickle() will raise a TypeError if it is passed a class.
2067
2068- Fixed a bug in gettext's "normalize and expand" code that prevented
2069 it from finding an existing .mo file.
2070
2071- Restored support for HTTP/0.9 servers in httplib.
2072
Tim Peters989b7b92000-10-16 20:24:53 +00002073- The math module was changed to stop raising OverflowError in case of
2074 underflow, and return 0 instead in underflow cases. Whether Python
2075 used to raise OverflowError in case of underflow was platform-
2076 dependent (it did when the platform math library set errno to ERANGE
2077 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002078
2079- Fixed a bug in StringIO that occurred when the file position was not
2080 at the end of the file and write() was called with enough data to
2081 extend past the end of the file.
2082
2083- Fixed a bug that caused Tkinter error messages to get lost on
2084 Windows. The bug was fixed by replacing direct use of
2085 interp->result with Tcl_GetStringResult(interp).
2086
2087- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2088 redirect response.
2089
2090- Several changes were made to distutils: Some debugging code was
2091 removed from util. Fixed the installer used when an external zip
2092 program (like WinZip) is not found; the source code for this
2093 installer is in Misc/distutils. check_lib() was modified to behave
2094 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2095 test for whether installed modules are on sys.path was changed to
2096 use both normcase() and normpath().
2097
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002098- Several minor bugs were fixed in the xml package (the minidom,
2099 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002100
2101- The regression test driver (regrtest.py) behavior when invoked with
2102 -l changed: It now reports a count of objects that are recognized as
2103 garbage but not freed by the garbage collector.
2104
Tim Peters989b7b92000-10-16 20:24:53 +00002105- The regression test for the math module was changed to test
2106 exceptional behavior when the test is run in verbose mode. Python
2107 cannot yet guarantee consistent exception behavior across platforms,
2108 so the exception part of test_math is run only in verbose mode, and
2109 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002110
2111Internals
2112
2113- PyOS_CheckStack() has been disabled on Win64, where it caused
2114 test_sre to fail.
2115
2116Build issues
2117
2118- Changed compiler flags, so that gcc is always invoked with -Wall and
2119 -Wstrict-prototypes. Users compiling Python with GCC should see
2120 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002121 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002122 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002123
Tim Petersa3a3a032000-11-30 05:22:44 +00002124- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002125
2126Tools and other miscellany
2127
2128- The compiler in Tools/compiler was updated to support the new
2129 language features introduced in 2.0: extended print statement, list
2130 comprehensions, and augmented assignments. The new compiler should
2131 also be backwards compatible with Python 1.5.2; the compiler will
2132 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002133 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002134
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002135What's new in 2.0 release candidate 1 (since beta 2)?
2136=====================================================
2137
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002138What is release candidate 1?
2139
2140We believe that release candidate 1 will fix all known bugs that we
2141intend to fix for the 2.0 final release. This release should be a bit
2142more stable than the previous betas. We would like to see even more
2143widespread testing before the final release, so we are producing this
2144release candidate. The final release will be exactly the same unless
2145any show-stopping (or brown bag) bugs are found by testers of the
2146release candidate.
2147
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002148All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002149to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002150
2151Core language, builtins, and interpreter
2152
2153- A bug that caused crashes when __coerce__ was used with augmented
2154 assignment, e.g. +=, was fixed.
2155
2156- Raise ZeroDivisionError when raising zero to a negative number,
2157 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2158 power operator and the result of math.pow(0.0, -2.0) will vary by
2159 platform. On Linux, it raises a ValueError.
2160
2161- A bug in Unicode string interpolation was fixed that occasionally
2162 caused errors with formats including "%%". For example, the
2163 following expression "%% %s" % u"abc" no longer raises a TypeError.
2164
2165- Compilation of deeply nested expressions raises MemoryError instead
2166 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2167
2168- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2169 rendering them useless. They are now written in binary mode again.
2170
2171Standard library
2172
2173- Keyword arguments are now accepted for most pattern and match object
2174 methods in SRE, the standard regular expression engine.
2175
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002176- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002177 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002178
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002179- Several bugs in the Unicode handling and error handling in _tkinter
2180 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002181
2182- Fix memory management errors in Merge() and Tkapp_Call() routines.
2183
2184- Several changes were made to cStringIO to make it compatible with
2185 the file-like object interface and with StringIO. If operations are
2186 performed on a closed object, an exception is raised. The truncate
2187 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002188 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002189
2190- There were many changes made to the linuxaudiodev module and its
2191 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002192 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002193
2194 Note that this module is named poorly, because it should work
2195 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002196 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002197
2198 The module now raises exceptions when errors occur instead of
2199 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2200 audio) and defines a getptr() method that calls the
2201 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2202
2203- The library_version attribute, introduced in an earlier beta, was
2204 removed because it can not be supported with early versions of the C
2205 readline library, which provides no way to determine the version at
2206 compile-time.
2207
2208- The binascii module is now enabled on Win64.
2209
Tim Peters46446d62000-10-09 21:19:31 +00002210- tokenize.py no longer suffers "recursion depth" errors when parsing
2211 programs with very long string literals.
2212
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002213Internals
2214
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002215- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002216 which is called when the interpreter starts up to determine where
2217 the standard library is installed. These vulnerabilities affect all
2218 previous versions of Python and can be exploited by setting very
2219 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2220 setuid Python script, although use of the wrapper in
2221 Misc/setuid-prog.c will eliminate the vulnerability.
2222
2223- Fixed garbage collection bugs in instance creation that were
2224 triggered when errors occurred during initialization. The solution,
2225 applied in cPickle and in PyInstance_New(), is to call
2226 PyObject_GC_Init() after the initialization of the object's
2227 container attributes is complete.
2228
2229- pyexpat adds definitions of PyModule_AddStringConstant and
2230 PyModule_AddObject if the Python version is less than 2.0, which
2231 provides compatibility with PyXML on Python 1.5.2.
2232
2233- If the platform has a bogus definition for LONG_BIT (the number of
2234 bits in a long), an error will be reported at compile time.
2235
2236- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2237 collection crashes and possibly other, unreported crashes.
2238
2239- Fixed a memory leak in _PyUnicode_Fini().
2240
2241Build issues
2242
2243- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002244 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002245 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002246
2247- The mmap.PAGESIZE constant is now initialized using sysconf when
2248 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2249
2250- The md5 file should now compile on all platforms.
2251
2252- The select module now compiles on platforms that do not define
2253 POLLRDNORM and related constants.
2254
2255- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002256 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002257
Jeremy Hylton10921202000-10-09 18:34:12 +00002258- BeOS: A number of changes were made to the build and installation
2259 process. ar-fake now operates on a directory of object files.
2260 dl_export.h is gone, and its macros now appear on the mwcc command
2261 line during build on PPC BeOS.
2262
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002263- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002264 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002265
2266- Cygwin: Support for shared libraries, Tkinter, and sockets.
2267
2268- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2269
2270Tools and other miscellany
2271
2272- Removed debugging prints from main used with freeze.
2273
Tim Peters46446d62000-10-09 21:19:31 +00002274- IDLE auto-indent no longer crashes when it encounters Unicode
2275 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002276
2277What's new in 2.0 beta 2 (since beta 1)?
2278========================================
2279
2280Core language, builtins, and interpreter
2281
Tim Peters482c0212000-09-26 06:33:09 +00002282- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002283 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002284
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002285- Add -h and -V command line options to print the usage message and
2286 Python version number and exit immediately.
2287
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002288- eval() and exec accept Unicode objects as code parameters.
2289
2290- getattr() and setattr() now also accept Unicode objects for the
2291 attribute name, which are converted to strings using the default
2292 encoding before lookup.
2293
2294- Multiplication on string and Unicode now does proper bounds
2295 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2296 string is too long."
2297
2298- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002299 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002300
Jeremy Hylton1b618592000-09-26 05:32:36 +00002301
2302Standard library and extensions
2303
Guido van Rossum5b08f132001-04-16 02:05:23 +00002304- socket module: the OpenSSL code now adds support for RAND_status()
2305 and EGD (Entropy Gathering Device).
2306
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002307- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002308 argument checking; it still takes no arguments.
2309
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002310- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002311
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002312- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002313
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002314- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002315
2316- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002317 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002318
2319- copy: Copy Unicode objects atomically.
2320
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002321- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002322
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002323- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002324
Fred Drake67233bc2000-09-26 16:40:27 +00002325- dbm: Add get() and setdefault() methods to dbm object. Add constant
2326 `library' to module that names the library used. Added doc strings
2327 and method names to error messages. Uses configure to determine
2328 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2329 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002330
2331- distutils: Update to version 0.9.3.
2332
2333- dl: Add several dl.RTLD_ constants.
2334
2335- fpectl: Now supported on FreeBSD.
2336
2337- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2338 found by the collector will be saved in gc.garbage. This is useful
2339 for debugging a program that creates reference cycles.
2340
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002341- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002342 of HTTP class. Do not close socket on zero-length response. Do not
2343 crash when server sends invalid content-length header.
2344
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002345- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002346
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002347- marshal: When reading a short, sign-extend on platforms where shorts
2348 are bigger than 16 bits. When reading a long, repair the unportable
2349 sign extension that was being done for 64-bit machines. (It assumed
2350 that signed right shift sign-extends.)
2351
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002352- operator: Add contains(), invert(), __invert__() as aliases for
2353 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002354
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002355- os: Add support for popen2() and popen3() on all platforms where
2356 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002357
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002358- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002359 clicking on a file in Explorer (or passing the file name to the
2360 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002361
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002362- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002363 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002364
2365- pickle: Now raises ValueError when an invalid pickle that contains
2366 a non-string repr where a string repr was expected. This behavior
2367 matches cPickle.
2368
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002369- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002370
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002371- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002372
2373- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002374 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002375 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002376
2377- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002378 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002379
2380- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002381 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002382 few cycles during startup since the first call to
2383 setdefaultencoding() will initialize the codec registry and the
2384 encodings package.
2385
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002386- socket: Support for size hint in readlines() method of object returned
2387 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002388
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002389- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002390 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002391 is followed by whitespace.
2392
Tim Petersa3a3a032000-11-30 05:22:44 +00002393- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002394
2395- struct: Check ranges for bytes and shorts.
2396
2397- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002398 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002399
2400- Tkinter: Image objects are now guaranteed to have unique ids. Set
2401 event.delta to zero if Tk version doesn't support mousewheel.
2402 Removed some debugging prints.
2403
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002404- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002405
Fred Drake67233bc2000-09-26 16:40:27 +00002406- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002407 which works around a bug in Norton AntiVirus 2000 that leads directly
2408 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002409
2410- xml: New version detection code allows PyXML to override standard
2411 XML package if PyXML version is greater than 0.6.1.
2412
Fred Drake64bb3802000-09-26 16:21:35 +00002413- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2414 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2415 tree only for nodes which are sufficiently interesting to a specific
2416 application. Does not provide the HTML-specific extensions. Still
2417 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002418
Fred Drake64bb3802000-09-26 16:21:35 +00002419- xml.sax: SAX 2 support for Python, including all the handler
2420 interfaces needed to process XML 1.0 compliant XML. Some
2421 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002422
Fred Drake64bb3802000-09-26 16:21:35 +00002423- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2424 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002425
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002426
Jeremy Hylton1b618592000-09-26 05:32:36 +00002427C API
2428
2429- Add three new convenience functions for module initialization --
2430 PyModule_AddObject(), PyModule_AddIntConstant(), and
2431 PyModule_AddStringConstant().
2432
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002433- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002434 removed and add #error to Python.h if NULL isn't defined after
2435 #include of stdio.h.
2436
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002437- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002438 backwards compatibility (at the source level) with old extensions.
2439
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002440- A wrapper API was added for signal() and sigaction(). Instead of
2441 either function, always use PyOS_getsig() to get a signal handler
2442 and PyOS_setsig() to set one. A new convenience typedef
2443 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002444
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002445- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002446 internal data buffer and size of a string object -- or the default
2447 encoded version of a Unicode object.
2448
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002449- PyString_Size() and PyString_AsString() accept Unicode objects.
2450
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002451- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002452 exists). INT_MAX and LONG_MAX will always be defined, even if
2453 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002454
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002455- PyFloat_FromString takes a second argument, pend, that was
2456 effectively useless. It is now officially useless but preserved for
2457 backwards compatibility. If the pend argument is not NULL, *pend is
2458 set to NULL.
2459
2460- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2461 for the attribute name. See note on getattr() above.
2462
2463- A few bug fixes to argument processing for Unicode.
2464 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2465 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2466 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002467 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002468
2469- Py_BuildValue accepts B format (for bgen-generated code).
2470
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002471
Jeremy Hylton1b618592000-09-26 05:32:36 +00002472Internals
2473
2474- On Unix, fix code for finding Python installation directory so that
2475 it works when argv[0] is a relative path.
2476
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002477- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002478 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002479 rather than by generating a copy of the object.
2480
Tim Peters482c0212000-09-26 06:33:09 +00002481- Several of the internal Unicode tables are much smaller now, and
2482 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002483
Jeremy Hylton97693b02000-09-26 17:42:51 +00002484- In the garbage collector: Fixed bug in collection of tuples. Fixed
2485 bug that caused some instances to be removed from the container set
2486 while they were still live. Fixed parsing in gc.set_debug() for
2487 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002488
2489- Fixed refcount problem in instance deallocation that only occurred
2490 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2491
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002492- On Windows, getpythonregpath is now protected against null data in
2493 registry key.
2494
2495- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002496 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002497
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002498
Jeremy Hylton1b618592000-09-26 05:32:36 +00002499Build and platform-specific issues
2500
2501- Better support of GNU Pth via --with-pth configure option.
2502
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002503- Python/C API now properly exposed to dynamically-loaded extension
2504 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002505
2506- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2507 Don't define MS_SYNC to be zero when it is undefined. Added missing
2508 prototypes in posixmodule.c.
2509
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002510- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002511 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002512
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002513- Fix largefile support on older NetBSD systems and OpenBSD by adding
2514 define for TELL64.
2515
2516
2517Tools and other miscellany
2518
2519- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2520
2521- freeze: The modulefinder now works with 2.0 opcodes.
2522
Tim Petersa3a3a032000-11-30 05:22:44 +00002523- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002524 Move hackery of sys.argv until after the Tk instance has been
2525 created, which allows the application-specific Tkinter
2526 initialization to be executed if present; also pass an explicit
2527 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002528
Jeremy Hylton1b618592000-09-26 05:32:36 +00002529
2530What's new in 2.0 beta 1?
2531=========================
2532
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002533Source Incompatibilities
2534------------------------
2535
2536None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2537such as single-argument append(), connect() and bind(), and changes to
2538str(long) and repr(float).
2539
2540
2541Binary Incompatibilities
2542------------------------
2543
2544- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2545with Python 2.0; these extensions will have to be rebuilt for Python
25462.0.
2547
2548- On Windows, attempting to import a third party extension built for
2549Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2550can do about this. Check your PYTHONPATH environment variable!
2551
2552- Python bytecode files (*.pyc and *.pyo) are not compatible between
2553releases.
2554
2555
2556Overview of Changes Since 1.6
2557-----------------------------
2558
2559There are many new modules (including brand new XML support through
2560the xml package, and i18n support through the gettext module); a list
2561of all new modules is included below. Lots of bugs have been fixed.
2562
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002563The process for making major new changes to the language has changed
2564since Python 1.6. Enhancements must now be documented by a Python
2565Enhancement Proposal (PEP) before they can be accepted.
2566
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002567There are several important syntax enhancements, described in more
2568detail below:
2569
2570 - Augmented assignment, e.g. x += 1
2571
2572 - List comprehensions, e.g. [x**2 for x in range(10)]
2573
2574 - Extended import statement, e.g. import Module as Name
2575
2576 - Extended print statement, e.g. print >> file, "Hello"
2577
2578Other important changes:
2579
2580 - Optional collection of cyclical garbage
2581
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002582Python Enhancement Proposal (PEP)
2583---------------------------------
2584
2585PEP stands for Python Enhancement Proposal. A PEP is a design
2586document providing information to the Python community, or describing
2587a new feature for Python. The PEP should provide a concise technical
2588specification of the feature and a rationale for the feature.
2589
2590We intend PEPs to be the primary mechanisms for proposing new
2591features, for collecting community input on an issue, and for
2592documenting the design decisions that have gone into Python. The PEP
2593author is responsible for building consensus within the community and
2594documenting dissenting opinions.
2595
2596The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002597
2598Augmented Assignment
2599--------------------
2600
2601This must have been the most-requested feature of the past years!
2602Eleven new assignment operators were added:
2603
Guido van Rossume905e952000-09-05 12:42:46 +00002604 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002605
2606For example,
2607
2608 A += B
2609
2610is similar to
2611
2612 A = A + B
2613
2614except that A is evaluated only once (relevant when A is something
2615like dict[index].attr).
2616
2617However, if A is a mutable object, A may be modified in place. Thus,
2618if A is a number or a string, A += B has the same effect as A = A+B
2619(except A is only evaluated once); but if a is a list, A += B has the
2620same effect as A.extend(B)!
2621
2622Classes and built-in object types can override the new operators in
2623order to implement the in-place behavior; the not-in-place behavior is
2624used automatically as a fallback when an object doesn't implement the
2625in-place behavior. For classes, the method name is derived from the
2626method name for the corresponding not-in-place operator by inserting
2627an 'i' in front of the name, e.g. __iadd__ implements in-place
2628__add__.
2629
2630Augmented assignment was implemented by Thomas Wouters.
2631
2632
2633List Comprehensions
2634-------------------
2635
2636This is a flexible new notation for lists whose elements are computed
2637from another list (or lists). The simplest form is:
2638
2639 [<expression> for <variable> in <sequence>]
2640
Guido van Rossum56db0952000-09-06 23:34:25 +00002641For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002642This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002643
2644You can also add a condition:
2645
2646 [<expression> for <variable> in <sequence> if <condition>]
2647
2648For example, [w for w in words if w == w.lower()] would yield the list
2649of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002650than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002651
2652You can also have nested for loops and more than one 'if' clause. For
2653example, here's a function that flattens a sequence of sequences::
2654
2655 def flatten(seq):
2656 return [x for subseq in seq for x in subseq]
2657
2658 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2659
2660This prints
2661
2662 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2663
2664List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002665Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002666
2667
2668Extended Import Statement
2669-------------------------
2670
2671Many people have asked for a way to import a module under a different
2672name. This can be accomplished like this:
2673
2674 import foo
2675 bar = foo
2676 del foo
2677
2678but this common idiom gets old quickly. A simple extension of the
2679import statement now allows this to be written as follows:
2680
2681 import foo as bar
2682
2683There's also a variant for 'from ... import':
2684
2685 from foo import bar as spam
2686
2687This also works with packages; e.g. you can write this:
2688
2689 import test.regrtest as regrtest
2690
2691Note that 'as' is not a new keyword -- it is recognized only in this
2692context (this is only possible because the syntax for the import
2693statement doesn't involve expressions).
2694
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002695Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002696
2697
2698Extended Print Statement
2699------------------------
2700
2701Easily the most controversial new feature, this extension to the print
2702statement adds an option to make the output go to a different file
2703than the default sys.stdout.
2704
2705For example, to write an error message to sys.stderr, you can now
2706write:
2707
2708 print >> sys.stderr, "Error: bad dog!"
2709
2710As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002711evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002712
2713 print >> None, "Hello world"
2714
2715is equivalent to
2716
2717 print "Hello world"
2718
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002719Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002720
2721
2722Optional Collection of Cyclical Garbage
2723---------------------------------------
2724
2725Python is now equipped with a garbage collector that can hunt down
2726cyclical references between Python objects. It's no replacement for
2727reference counting; in fact, it depends on the reference counts being
2728correct, and decides that a set of objects belong to a cycle if all
2729their reference counts can be accounted for from their references to
2730each other. This devious scheme was first proposed by Eric Tiedemann,
2731and brought to implementation by Neil Schemenauer.
2732
2733There's a module "gc" that lets you control some parameters of the
2734garbage collection. There's also an option to the configure script
2735that lets you enable or disable the garbage collection. In 2.0b1,
2736it's on by default, so that we (hopefully) can collect decent user
2737experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002738performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002739off by default in the final 2.0 release.
2740
2741
2742Smaller Changes
2743---------------
2744
2745A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2746map(None, seq1, seq2, ...) when the sequences have the same length;
2747i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2748the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002749zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002750
2751sys.version_info is a tuple (major, minor, micro, level, serial).
2752
2753Dictionaries have an odd new method, setdefault(key, default).
2754dict.setdefault(key, default) returns dict[key] if it exists; if not,
2755it sets dict[key] to default and returns that value. Thus:
2756
2757 dict.setdefault(key, []).append(item)
2758
2759does the same work as this common idiom:
2760
2761 if not dict.has_key(key):
2762 dict[key] = []
2763 dict[key].append(item)
2764
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002765There are two new variants of SyntaxError that are raised for
2766indentation-related errors: IndentationError and TabError.
2767
2768Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2769escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002770
2771The limits on the size of expressions and file in Python source code
2772have been raised from 2**16 to 2**32. Previous versions of Python
2773were limited because the maximum argument size the Python VM accepted
2774was 2**16. This limited the size of object constructor expressions,
2775e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2776limit was raised thanks to a patch by Charles Waldman that effectively
2777fixes the problem. It is now much more likely that you will be
2778limited by available memory than by an arbitrary limit in Python.
2779
2780The interpreter's maximum recursion depth can be modified by Python
2781programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2782limit is the maximum number of recursive calls that can be made by
2783Python code. The limit exists to prevent infinite recursion from
2784overflowing the C stack and causing a core dump. The default value is
27851000. The maximum safe value for a particular platform can be found
2786by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002787
2788New Modules and Packages
2789------------------------
2790
2791atexit - for registering functions to be called when Python exits.
2792
2793imputil - Greg Stein's alternative API for writing custom import
2794hooks.
2795
2796pyexpat - an interface to the Expat XML parser, contributed by Paul
2797Prescod.
2798
2799xml - a new package with XML support code organized (so far) in three
2800subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2801would fill a volume. There's a special feature whereby a
2802user-installed package named _xmlplus overrides the standard
2803xmlpackage; this is intended to give the XML SIG a hook to distribute
2804backwards-compatible updates to the standard xml package.
2805
2806webbrowser - a platform-independent API to launch a web browser.
2807
2808
Guido van Rossume905e952000-09-05 12:42:46 +00002809Changed Modules
2810---------------
2811
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002812array -- new methods for array objects: count, extend, index, pop, and
2813remove
2814
2815binascii -- new functions b2a_hex and a2b_hex that convert between
2816binary data and its hex representation
2817
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002818calendar -- Many new functions that support features including control
2819over which day of the week is the first day, returning strings instead
2820of printing them. Also new symbolic constants for days of week,
2821e.g. MONDAY, ..., SUNDAY.
2822
2823cgi -- FieldStorage objects have a getvalue method that works like a
2824dictionary's get method and returns the value attribute of the object.
2825
2826ConfigParser -- The parser object has new methods has_option,
2827remove_section, remove_option, set, and write. They allow the module
2828to be used for writing config files as well as reading them.
2829
2830ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002831optionally support the RFC 959 REST command.
2832
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002833gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002834
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002835httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2836the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002837
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002838locale -- implement getdefaultlocale for Win32 and Macintosh
2839
2840marshal -- no longer dumps core when marshaling deeply nested or
2841recursive data structures
2842
2843os -- new functions isatty, seteuid, setegid, setreuid, setregid
2844
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002845os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2846support under Unix.
2847
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002848os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002849
2850os.path -- fix semantics of os.path.commonprefix
2851
2852smtplib -- support for sending very long messages
2853
2854socket -- new function getfqdn()
2855
2856readline -- new functions to read, write and truncate history files.
2857The readline section of the library reference manual contains an
2858example.
2859
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002860select -- add interface to poll system call
2861
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002862shutil -- new copyfileobj function
2863
2864SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2865HTTP server.
2866
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002867Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002868
2869urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002870e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002871
2872whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002873
2874
2875Obsolete Modules
2876----------------
2877
2878None. However note that 1.6 made a whole slew of modules obsolete:
2879stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2880poly, zmod, strop, util, whatsound.
2881
2882
2883Changed, New, Obsolete Tools
2884----------------------------
2885
Tim Peters8b092332000-09-05 20:15:25 +00002886None.
Guido van Rossume905e952000-09-05 12:42:46 +00002887
2888
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002889C-level Changes
2890---------------
2891
2892Several cleanup jobs were carried out throughout the source code.
2893
2894All C code was converted to ANSI C; we got rid of all uses of the
2895Py_PROTO() macro, which makes the header files a lot more readable.
2896
2897Most of the portability hacks were moved to a new header file,
2898pyport.h; several other new header files were added and some old
2899header files were removed, in an attempt to create a more rational set
2900of header files. (Few of these ever need to be included explicitly;
2901they are all included by Python.h.)
2902
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002903Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002904and Win64, especially for the new Intel Itanium processor. Mick also
2905added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002906
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002907The C APIs to return an object's size have been update to consistently
2908use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2909previous versions, the abstract interfaces used PyXXX_Length and the
2910concrete interfaces used PyXXX_Size. The old names,
2911e.g. PyObject_Length, are still available for backwards compatibility
2912at the API level, but are deprecated.
2913
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002914The PyOS_CheckStack function has been implemented on Windows by
2915Fredrik Lundh. It prevents Python from failing with a stack overflow
2916on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002917
2918The GC changes resulted in creation of two new slots on object,
2919tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002920the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002921
2922The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002923C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002924
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002925PyErr_Format has been updated to automatically calculate the size of
2926the buffer needed to hold the formatted result string. This change
2927prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002928
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002929New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002930
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002931PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2932that are the same as their non-Ex counterparts except they take an
2933extra flag argument that tells them to close the file when done.
2934
2935XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002936
Tim Peters8b092332000-09-05 20:15:25 +00002937
2938Windows Changes
2939---------------
2940
2941New popen2/popen3/peopen4 in os module (see Changed Modules above).
2942
2943os.popen is much more usable on Windows 95 and 98. See Microsoft
2944Knowledge Base article Q150956. The Win9x workaround described there
2945is implemented by the new w9xpopen.exe helper in the root of your
2946Python installation. Note that Python uses this internally; it is not
2947a standalone program.
2948
2949Administrator privileges are no longer required to install Python
2950on Windows NT or Windows 2000. If you have administrator privileges,
2951Python's registry info will be written under HKEY_LOCAL_MACHINE.
2952Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002953under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002954uses of Python, but will prevent some advanced uses from working
2955(for example, running a Python script as an NT service, or possibly
2956from CGI).
2957
2958[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2959installer; instead, it installs the needed Tcl/Tk files directly in the
2960Python directory. If you already have a Tcl/Tk installation, this
2961wastes some disk space (about 4 Megs) but avoids problems with
2962conflicting Tcl/Tk installations, and makes it much easier for Python
2963to ensure that Tcl/Tk can find all its files.
2964
2965[This was new in 1.6] The Windows installer now installs by default in
2966\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002968
2969Updates to the changes between 1.5.2 and 1.6
2970--------------------------------------------
2971
2972The 1.6 NEWS file can't be changed after the release is done, so here
2973is some late-breaking news:
2974
2975New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2976and changes to getlocale() and setlocale().
2977
2978The new module is now enabled per default.
2979
2980It is not true that the encodings codecs cannot be used for normal
2981strings: the string.encode() (which is also present on 8-bit strings
2982!) allows using them for 8-bit strings too, e.g. to convert files from
2983cp1252 (Windows) to latin-1 or vice-versa.
2984
2985Japanese codecs are available from Tamito KAJIYAMA:
2986http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2987
2988
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002989======================================================================