blob: 38b80dc46271ba943da5e1aff86b80f5e03b8a60 [file] [log] [blame]
Tim Peters84362bc2001-10-19 17:55:30 +00001What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +00002Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +00003===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum3d27df02001-11-15 20:27:54 +00007- Multiple inheritance mixing new-style and classic classes in the
8 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +00009
10 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +000011 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +000012
13 The MRO (method resolution order) for each base class is respected
14 according to its kind, but the MRO for the derived class is computed
15 using new-style MRO rules if any base clase is a new-style class.
16 This needs to be documented.
17
Tim Petersa427a2b2001-10-29 22:25:45 +000018- The new builtin dictionary() constructor, and dictionary type, have
19 been renamed to dict. This reflects a decade of common usage.
20
Guido van Rossum3fc08d22001-11-15 20:33:10 +000021- dict() now accepts an iterable object producing 2-sequences. For
22 example, dict(d.items()) == d for any dictionary d. The argument,
23 and the elements of the argument, can be any iterable objects.
24
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000025- New-style classes can now have a __del__ method, which is called
26 when the instance is deleted (just like for classic classes).
27
Guido van Rossum12d955c2001-10-26 14:56:06 +000028- Assignment to object.__dict__ is now possible, for objects that are
29 instances of new-style classes that have a __dict__ (unless the base
30 class forbids it).
31
Guido van Rossumc8e56452001-10-22 00:43:43 +000032- Methods of built-in types now properly check for keyword arguments
33 (formerly these were silently ignored). The only built-in methods
34 that take keyword arguments are __call__, __init__ and __new__.
35
Guido van Rossum86443212001-10-27 22:28:54 +000036- The socket function has been converted to a type; see below.
37
Tim Peters84362bc2001-10-19 17:55:30 +000038Core and builtins
39
Jeremy Hylton249aaed2001-11-09 21:06:24 +000040- Assignment to __debug__ raises SyntaxError at compile-time. This
41 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +000042 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +000043
Guido van Rossum12d955c2001-10-26 14:56:06 +000044- Clarified the error messages for unsupported operands to an operator
45 (like 1 + '').
46
Tim Peters84362bc2001-10-19 17:55:30 +000047Extension modules
48
Tim Peters5ebfd362001-11-13 23:11:19 +000049- mmap has a new keyword argument, "access", allowing a uniform way for
50 both Windows and Unix users to create read-only, write-through and
51 copy-on-write memory mappings. This was previously possible only on
52 Unix. A new keyword argument was required to support this in a
53 uniform way because the mmap() signuatures had diverged across
54 platforms. Thanks to Jay T Miller for repairing this!
55
Tim Peters169ded02001-11-03 19:57:21 +000056- By default, the gc.garbage list now contains only those instances in
57 unreachable cycles that have __del__ methods; in 2.1 it contained all
58 instances in unreachable cycles. "Instances" here has been generalized
59 to include instances of both new-style and old-style classes.
60
Guido van Rossum12d955c2001-10-26 14:56:06 +000061- The socket module defines a new method for socket objects,
62 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000063 send() until all data has been sent. Also, the socket function has
64 been converted to a subclassable type, like list and tuple (etc.)
65 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000066
67- Various bugfixes to the curses module. There is now a test suite
68 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +000069
Guido van Rossum692adf12001-10-30 03:03:03 +000070- binascii.b2a_base64 no longer places an arbitrary restriction of 57
71 bytes on its input.
72
Tim Peters84362bc2001-10-19 17:55:30 +000073Library
74
Tim Peters5ebfd362001-11-13 23:11:19 +000075- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +000076 convenience function.
77
Tim Peters75335872001-11-03 19:35:43 +000078- Symbolic group names in regular expressions must be unique. For
79 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
80 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +000081 Python 2.2 detects this error at regexp compilation time;
82 previously, the error went undetected, and results were
83 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
84 pattern.subn() methods have been rewritten in C. Also, an
85 experimental function/method finditer() has been added, which works
86 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +000087
Martin v. Löwisb7b32602001-11-02 23:48:20 +000088- Tix exposes more commands through the classes DirSelectBox,
89 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
90 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
91 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
92
Tim Peters98791af2001-10-23 01:59:54 +000093- Traceback objects are now scanned by cyclic garbage collection, so
94 cycles created by casual use of sys.exc_info() no longer cause
95 permanent memory leaks (provided garbage collection is enabled).
96
Guido van Rossum49192142001-10-24 20:51:44 +000097- os.extsep -- a new variable needed by the RISCOS support. It is the
98 separator used by extensions, and is '.' on all platforms except
99 RISCOS, where it is '/'. There is no need to use this variable
100 unless you have a masochistic desire to port your code to RISCOS.
101
Barry Warsaw012852b2001-11-16 16:17:27 +0000102- mimetypes.py has optional support for non-standard, but commonly
103 found types. guess_type() and guess_extension() now accept an
104 optional `strict' flag, defaulting to true, which controls whether
105 recognize non-standard types or not. A few non-standard types we
106 know about have been added. Also, when run as a script, there are
107 new -l and -e options.
108
109- statcache is now deprecated.
110
111- email.Utils.formatdate() now produces the preferred RFC 2822 style
112 dates with numeric timezones (it used to produce obsolete dates
113 hard coded to "GMT" timezone). An optional `localtime' flag is
114 added to produce dates in the local timezone, with daylight savings
115 time properly taken into account.
116
117- In pickle and cPickle, instead of masking errors in load() by
118 transforming them into SystemError, we let the original exception
119 propagate out. Also, implement support for __safe_for_unpickling__
120 in pickle, as it already was supported in cPickle.
121
Tim Peters84362bc2001-10-19 17:55:30 +0000122Tools/Demos
123
124Build
125
Barry Warsaw012852b2001-11-16 16:17:27 +0000126- The dbm module is built using libdb1 if available. The bsddb module
127 is built with libdb3 if available.
128
129- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
130
Tim Peters84362bc2001-10-19 17:55:30 +0000131C API
132
Tim Peters1fc240e2001-10-26 05:06:50 +0000133- New function PySequence_Fast_GET_SIZE() returns the size of a non-
134 NULL result from PySequence_Fast(), more quickly than calling
135 PySequence_Size().
136
Barry Warsaw012852b2001-11-16 16:17:27 +0000137- New argument unpacking function PyArg_UnpackTuple() added.
138
139- New functions PyObject_CallFunctionObjArgs() and
140 PyObject_CallMethodObjArgs() have been added to make it more
141 convenient and efficient to call functions and methods from C.
142
143- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
144 possible that this will propagate errors it didn't before.
145
146- New function PyObject_CheckReadBuffer(), which returns true if its
147 argument supports the single-segment readable buffer interface.
148
Tim Peters84362bc2001-10-19 17:55:30 +0000149New platforms
150
Guido van Rossum86443212001-10-27 22:28:54 +0000151- We've finally confirmed that this release builds on HP-UX 11.00,
152 *with* threads, and passes the test suite.
153
Tim Peters7a33d8b2001-11-05 02:51:07 +0000154- Thanks to a series of patches from Michael Muller, Python may build
155 again under OS/2 Visual Age C++.
156
Guido van Rossum49192142001-10-24 20:51:44 +0000157- Updated RISCOS port by Dietmar Schwertberger.
158
Tim Peters84362bc2001-10-19 17:55:30 +0000159Tests
160
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000161- Added a test script for the curses module. It isn't run automatically;
162 regrtest.py must be run with '-u curses' to enable it.
163
Tim Peters84362bc2001-10-19 17:55:30 +0000164Windows
165
Barry Warsaw012852b2001-11-16 16:17:27 +0000166Mac
167
168- PythonScript has been moved to unsupported and is slated to be
169 removed completely in the next release.
170
171- It should now be possible to build applets that work on both OS9 and
172 OSX.
173
174- The core is now linked with CoreServices not Carbon; as a side
175 result, default 8bit encoding on OSX is now ASCII.
176
177- Python should now build on OSX 10.1.1
178
Tim Peters84362bc2001-10-19 17:55:30 +0000179
Tim Petersabf925f2001-09-28 21:53:42 +0000180What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000181Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000182===========================
183
184Type/class unification and new-style classes
185
Guido van Rossum687ae002001-10-15 22:03:32 +0000186- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000187 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000188 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000189 remains: the __dict__ of a new-style class is a read-only proxy; you
190 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000191 __defined__ attribute of new-style types no longer exists, for lack
192 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000193 future a __cache__ may be resurrected with a similar function, if I
194 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000195
Tim Peters1c9ca872001-10-04 06:43:12 +0000196- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
197 always returned None, even when there was a class docstring).
198
199- doctest now finds and runs docstrings attached to new-style classes,
200 class methods, static methods, and properties.
201
Guido van Rossum9074ef62001-10-16 21:34:49 +0000202Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000203
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000204- A very subtle syntactical pitfall in list comprehensions was fixed.
205 For example: [a+b for a in 'abc', for b in 'def']. The comma in
206 this example is a mistake. Previously, this would silently let 'a'
207 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
208 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
209 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
210 Note that [a for a in <singleton>] is a convoluted way to say
211 [<singleton>] anyway, so it's not like any expressiveness is lost.
212
Guido van Rossum9074ef62001-10-16 21:34:49 +0000213- getattr(obj, name, default) now only catches AttributeError, as
214 documented, rather than returning the default value for all
215 exceptions (which could mask bugs in a __getattr__ hook, for
216 example).
217
Fred Drakecb7a6b52001-10-22 18:41:51 +0000218- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000219 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000220 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000221 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000222
Guido van Rossum1c486092001-10-19 02:05:35 +0000223- unicode(obj) now behaves more like str(obj), accepting arbitrary
224 objects, and calling a __unicode__ method if it exists.
225 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000226 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000227
Barry Warsawf6fb1712001-10-19 05:35:40 +0000228- isinstance() now allows any object as the first argument and a
229 class, a type or something with a __bases__ tuple attribute for the
230 second argument. The second argument may also be a tuple of a
231 class, type, or something with __bases__, in which case isinstance()
232 will return true if the first argument is an instance of any of the
233 things contained in the second argument tuple. E.g.
234
235 isinstance(x, (A, B))
236
237 returns true if x is an instance of A or B.
238
Guido van Rossum9074ef62001-10-16 21:34:49 +0000239Extension modules
240
241- thread.start_new_thread() now returns the thread ID (previously None).
242
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000243- binascii has now two quopri support functions, a2b_qp and b2a_qp.
244
Guido van Rossumc524d952001-10-19 01:31:59 +0000245- readline now supports setting the startup_hook and the
246 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000247
Guido van Rossumc524d952001-10-19 01:31:59 +0000248- os and posix supports chroot(), setgroups() and unsetenv() where
249 available. The stat(), fstat(), statvfs() and fstatvfs() functions
250 now return "pseudo-sequences" -- the various fields can now be
251 accessed as attributes (e.g. os.stat("/").st_mtime) but for
252 backwards compatibility they also behave as a fixed-length sequence.
253 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000254 attributes.
255
256- time: localtime(), gmtime() and strptime() now return a
257 pseudo-sequence similar to the os.stat() return value, with
258 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000259
Guido van Rossum9074ef62001-10-16 21:34:49 +0000260- Decompression objects in the zlib module now accept an optional
261 second parameter to decompress() that specifies the maximum amount
262 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000263
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000264- optional SSL support in the socket module now exports OpenSSL
265 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
266 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000267 automatically seed its PRNG. Also, the keyfile and certfile
268 arguments to socket.ssl() are now optional.
269
270- posixmodule (and by extension, the os module on POSIX platforms) now
271 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000272
Guido van Rossum9074ef62001-10-16 21:34:49 +0000273Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000274
Tim Peters7402f792001-10-02 03:53:41 +0000275- doctest now excludes functions and classes not defined by the module
276 being tested, thanks to Tim Hochberg.
277
Fred Drakecb7a6b52001-10-22 18:41:51 +0000278- HotShot, a new profiler implemented using a C-based callback, has
279 been added. This substantially reduces the overhead of profiling,
280 but it is still quite preliminary. Support modules and
281 documentation will be added in upcoming releases (before 2.2 final).
282
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000283- profile now produces correct output in situations where an exception
284 raised in Python is cleared by C code (e.g. hasattr()). This used
285 to cause wrong output, including spurious claims of recursive
286 functions and attribution of time spent to the wrong function.
287
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000288 The code and documentation for the derived OldProfile and HotProfile
289 profiling classes was removed. The code hasn't worked for years (if
290 you tried to use them, they raised exceptions). OldProfile
291 intended to reproduce the behavior of the profiler Python used more
292 than 7 years ago, and isn't interesting anymore. HotProfile intended
293 to provide a faster profiler (but producing less information), and
294 that's a worthy goal we intend to meet via a different approach (but
295 without losing information).
296
Tim Peterscce092d2001-10-09 05:31:56 +0000297- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000298 a much better system-specific calibration constant. The constant can
299 now be specified in an instance constructor, or as a Profile class or
300 instance variable, instead of by editing profile.py's source code.
301 Calibration must still be done manually (see the docs for the profile
302 module).
303
304 Note that Profile.calibrate() must be overriden by subclasses.
305 Improving the accuracy required exploiting detailed knowledge of
306 profiler internals; the earlier method abstracted away the details
307 and measured a simplified model instead, but consequently computed
308 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000309
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000310- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000311 which indicates whether output is intended for the header 'Q'
312 encoding.
313
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000314- The SocketServer.ThreadingMixIn class now closes the request after
315 finish_request() returns. (Not when it errors out though.)
316
Barry Warsawf6fb1712001-10-19 05:35:40 +0000317- The nntplib module's NNTP.body() method has grown a `file' argument
318 to allow saving the message body to a file.
319
320- The email package has added a class email.Parser.HeaderParser which
321 only parses headers and does not recurse into the message's body.
322 Also, the module/class MIMEAudio has been added for representing
323 audio data (contributed by Anthony Baxter).
324
325- ftplib should be able to handle files > 2GB.
326
327- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
328 ON, and OFF.
329
Fred Drakecb7a6b52001-10-22 18:41:51 +0000330- xml.dom.minidom NodeList objects now support the length attribute
331 and item() method as required by the DOM specifications.
332
Guido van Rossumed554f62001-10-02 23:15:37 +0000333Tools/Demos
334
335- Demo/dns was removed. It no longer serves any purpose; a package
336 derived from it is now maintained by Anthony Baxter, see
337 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000338
Barry Warsawf6fb1712001-10-19 05:35:40 +0000339- The freeze tool has been made more robust, and two new options have
340 been added: -X and -E.
341
Tim Petersabf925f2001-09-28 21:53:42 +0000342Build
343
Barry Warsawf6fb1712001-10-19 05:35:40 +0000344- configure will use CXX in LINKCC if CXX is used to build main() and
345 the system requires to link a C++ main using the C++ compiler.
346
Tim Petersabf925f2001-09-28 21:53:42 +0000347C API
348
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000349- The documentation for the tp_compare slot is updated to require that
350 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
351 not correct. This is not yet enforced but will be enforced in
352 Python 2.3; even later, we may use -2 to indicate errors and +2 for
353 "NotImplemented". Right now, -1 should be used for an error return.
354
Tim Petersd38b1c72001-09-30 05:09:37 +0000355- PyLong_AsLongLong() now accepts int (as well as long) arguments.
356 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
357 as long) arguments.
358
Guido van Rossum3c288632001-10-16 21:13:49 +0000359- PyThread_start_new_thread() now returns a long int giving the thread
360 ID, if one can be calculated; it returns -1 for error, 0 if no
361 thread ID is calculated (this is an incompatible change, but only
362 the thread module used this API). This code has only really been
363 tested on Linux and Windows; other platforms please beware (and
364 report any bugs or strange behavior).
365
Guido van Rossum1c486092001-10-19 02:05:35 +0000366- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
367 input.
368
Tim Petersabf925f2001-09-28 21:53:42 +0000369New platforms
370
371Tests
372
373Windows
374
Tim Peters04cf1d32001-10-09 22:39:40 +0000375- Installer: If you install IDLE, and don't disable file-extension
376 registration, a new "Edit with IDLE" context (right-click) menu entry
377 is created for .py and .pyw files.
378
Tim Peters1ce3cf72001-10-01 17:58:40 +0000379- The signal module now supports SIGBREAK on Windows, thanks to Steven
380 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
381 action remains to call Win32 ExitProcess(). This can be changed via
382 signal.signal(). For example:
383
384 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
385 # (SIGINT) behavior.
386 import signal
387 signal.signal(signal.SIGBREAK,
388 signal.default_int_handler)
389
390 try:
391 while 1:
392 pass
393 except KeyboardInterrupt:
394 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
395 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
396 # program without the possibility for any Python-level cleanup).
397 print "Clean exit"
398
Tim Petersabf925f2001-09-28 21:53:42 +0000399
Tim Petersb07352e2001-09-08 01:25:47 +0000400What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000401Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000402===========================
403
Guido van Rossum808eea72001-09-25 04:15:41 +0000404Type/class unification and new-style classes
405
406- pydoc and inspect are now aware of new-style classes;
407 e.g. help(list) at the interactive prompt now shows proper
408 documentation for all operations on list objects.
409
410- Applications using Jim Fulton's ExtensionClass module can now safely
411 be used with Python 2.2. In particular, Zope 2.4.1 now works with
412 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
413 examples also work again. It is hoped that Gtk and Boost also work
414 with 2.2a4 and beyond. (If you can confirm this, please write
415 webmaster@python.org; if there are still problems, please open a bug
416 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000417
Tim Peters66c1a522001-09-24 21:17:50 +0000418- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
419 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
420 in the constructed property object. fget, fset and fdel weren't
421 discoverable from Python in 2.2a3. __doc__ is new, and allows to
422 associate a docstring with a property.
423
Guido van Rossum808eea72001-09-25 04:15:41 +0000424- Comparison overloading is now more completely implemented. For
425 example, a str subclass instance can properly be compared to a str
426 instance, and it can properly overload comparison. Ditto for most
427 other built-in object types.
428
429- The repr() of new-style classes has changed; instead of <type
430 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
431 *except* for built-in types, which are still rendered as <type
432 'Foo'> (to avoid upsetting existing code that might parse or
433 otherwise rely on repr() of certain type objects).
434
435- The repr() of new-style objects is now always <Foo object at XXX>;
436 previously, it was sometimes <Foo instance at XXX>.
437
438- For new-style classes, what was previously called __getattr__ is now
439 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000440 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000441 one in classic classes is defined which is called only if regular
442 attribute access raises AttributeError; to catch *all* attribute
443 access, you can use __getattribute__ (for new-style classes). If
444 both are defined, __getattribute__ is called first, and if it raises
445 AttributeError, __getattr__ is called.
446
447- The __class__ attribute of new-style objects can be assigned to.
448 The new class must have the same C-level object layout as the old
449 class.
450
451- The builtin file type can be subclassed now. In the usual pattern,
452 "file" is the name of the builtin type, and file() is a new builtin
453 constructor, with the same signature as the builtin open() function.
454 file() is now the preferred way to open a file.
455
456- Previously, __new__ would only see sequential arguments passed to
457 the type in a constructor call; __init__ would see both sequential
458 and keyword arguments. This made no sense whatsoever any more, so
459 now both __new__ and __init__ see all arguments.
460
461- Previously, hash() applied to an instance of a subclass of str or
462 unicode always returned 0. This has been repaired.
463
464- Previously, an operation on an instance of a subclass of an
465 immutable type (int, long, float, complex, tuple, str, unicode),
466 where the subtype didn't override the operation (and so the
467 operation was handled by the builtin type), could return that
468 instance instead a value of the base type. For example, if s was of
469 a str sublass type, s[:] returned s as-is. Now it returns a str
470 with the same value as s.
471
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000472- Provisional support for pickling new-style objects has been added.
473
Guido van Rossum808eea72001-09-25 04:15:41 +0000474Core
475
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000476- file.writelines() now accepts any iterable object producing strings.
477
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000478- PyUnicode_FromEncodedObject() now works very much like
479 PyObject_Str(obj) in that it tries to use __str__/tp_str
480 on the object if the object is not a string or buffer. This
481 makes unicode() behave like str() when applied to non-string/buffer
482 objects.
483
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000484- PyFile_WriteObject now passes Unicode objects to the file's write
485 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000486 of a print statement must support Unicode objects, i.e. they must
487 at least convert them into ASCII strings.
488
Guido van Rossum624c8af2001-09-18 15:21:04 +0000489- Thread scheduling on Solaris should be improved; it is no longer
490 necessary to insert a small sleep at the start of a thread in order
491 to let other runnable threads be scheduled.
492
Tim Petersb07352e2001-09-08 01:25:47 +0000493Library
494
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000495- StringIO.StringIO instances and cStringIO.StringIO instances support
496 read character buffer compatible objects for their .write() methods.
497 These objects are converted to strings and then handled as such
498 by the instances.
499
Barry Warsaw2f600732001-09-24 04:28:10 +0000500- The "email" package has been added. This is basically a port of the
501 mimelib package <http://sf.net/projects/mimelib> with API changes
502 and some implementations updated to use iterators and generators.
503
Tim Peters8a9c2842001-09-22 21:30:22 +0000504- difflib.ndiff() and difflib.Differ.compare() are generators now. This
505 restores the ability of Tools/scripts/ndiff.py to start producing output
506 before the entire comparison is complete.
507
Barry Warsaw58b072d2001-09-22 04:44:21 +0000508- StringIO.StringIO instances and cStringIO.StringIO instances support
509 iteration just like file objects (i.e. their .readline() method is
510 called for each iteration until it returns an empty string).
511
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000512- The codecs module has grown four new helper APIs to access
513 builtin codecs: getencoder(), getdecoder(), getreader(),
514 getwriter().
515
Guido van Rossum624c8af2001-09-18 15:21:04 +0000516- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
517 simplifies writing XML RPC servers.
518
Barry Warsaw647d5e82001-09-28 17:01:02 +0000519- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000520 after interpretation of symbolic links. On non-Unix systems, this
521 is an alias for os.path.abspath().
522
Tim Peters16a77ad2001-09-08 04:00:12 +0000523- operator.indexOf() (PySequence_Index() in the C API) now works with any
524 iterable object.
525
Guido van Rossum624c8af2001-09-18 15:21:04 +0000526- smtplib now supports various authentication and security features of
527 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000528
Guido van Rossum624c8af2001-09-18 15:21:04 +0000529- hmac: a new module implementing keyed hashing for message
530 authentication.
531
532- mimetypes now recognizes more extensions and file types. At the
533 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000534
Guido van Rossum624c8af2001-09-18 15:21:04 +0000535- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000536 Python 2.2 bytecode generation. It has also been promoted from a
537 Tool to a standard library package. (Tools/compiler still exists as
538 a sample driver.)
539
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000540Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000541
Tim Petersb07352e2001-09-08 01:25:47 +0000542Build
543
Guido van Rossum624c8af2001-09-18 15:21:04 +0000544- Large file support (LFS) is now automatic when the platform supports
545 it; no more manual configuration tweaks are needed. On Linux, at
546 least, it's possible to have a system whose C library supports large
547 files but whose kernel doesn't; in this case, large file support is
548 still enabled but doesn't do you any good unless you upgrade your
549 kernel or share your Python executable with another system whose
550 kernel has large file support.
551
552- The configure script now supplies plausible defaults in a
553 cross-compilation environment. This doesn't mean that the supplied
554 values are always correct, or that cross-compilation now works
555 flawlessly -- but it's a first step (and it shuts up most of
556 autoconf's warnings about AC_TRY_RUN).
557
558- The Unix build is now a bit less chatty, courtesy of the parser
559 generator. The build is completely silent (except for errors) when
560 using "make -s", thanks to a -q option to setup.py.
561
Tim Petersb07352e2001-09-08 01:25:47 +0000562C API
563
Guido van Rossum624c8af2001-09-18 15:21:04 +0000564- The "structmember" API now supports some new flag bits to deny read
565 and/or write access to attributes in restricted execution mode.
566
Tim Petersb07352e2001-09-08 01:25:47 +0000567New platforms
568
Guido van Rossum624c8af2001-09-18 15:21:04 +0000569- Compaq's iPAQ handheld, running the "familiar" Linux distribution
570 (http://familiar.handhelds.org).
571
Tim Petersb07352e2001-09-08 01:25:47 +0000572Tests
573
Tim Peters8a9c2842001-09-22 21:30:22 +0000574- The "classic" standard tests, which work by comparing stdout to
575 an expected-output file under Lib/test/output/, no longer stop at
576 the first mismatch. Instead the test is run to completion, and a
577 variant of ndiff-style comparison is used to report all differences.
578 This is much easier to understand than the previous style of reporting.
579
580- The unittest-based standard tests now use regrtest's test_main()
581 convention, instead of running as a side-effect of merely being
582 imported. This allows these tests to be run in more natural and
583 flexible ways as unittests, outside the regrtest framework.
584
585- regrtest.py is much better integrated with unittest and doctest now,
586 especially in regard to reporting errors.
587
Tim Petersb07352e2001-09-08 01:25:47 +0000588Windows
589
Guido van Rossum624c8af2001-09-18 15:21:04 +0000590- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000591 that support it (NTFS under Windows 2000). See "What's New in
592 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000593
Tim Petersb07352e2001-09-08 01:25:47 +0000594
Tim Petersedc99312001-08-22 21:36:50 +0000595What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000596Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000597===========================
598
599Core
600
Tim Peters9fffa3e2001-09-04 05:14:19 +0000601- Conversion of long to float now raises OverflowError if the long is too
602 big to represent as a C double.
603
Tim Peters32f453e2001-09-03 08:35:41 +0000604- The 3-argument builtin pow() no longer allows a third non-None argument
605 if either of the first two arguments is a float, or if both are of
606 integer types and the second argument is negative (in which latter case
607 the arguments are converted to float, so this is really the same
608 restriction).
609
Tim Peters5d2b77c2001-09-03 05:47:38 +0000610- The builtin dir() now returns more information, and sometimes much
611 more, generally naming all attributes of an object, and all attributes
612 reachable from the object via its class, and from its class's base
613 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
614 an empty list. In 2.2a3,
615
616 >>> dir([])
617 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
618 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
619 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
620 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
621 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
622 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
623 'reverse', 'sort']
624
625 dir(module) continues to return only the module's attributes, though.
626
Tim Petersbdee63f2001-09-02 03:40:59 +0000627- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000628 than raising OverflowError. This is a partial implementation of PEP
629 237. You can use -Wdefault::OverflowWarning to enable a warning for
630 this situation, and -Werror::OverflowWarning to revert to the old
631 OverflowError exception.
632
Guido van Rossum61c345f2001-09-04 03:26:15 +0000633- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000634 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000635 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
636 -Qold, meaning the / operator has its classic meaning and no
637 warnings are issued. Using -Qwarn issues a run-time warning about
638 all uses of classic division for int and long arguments; -Qwarnall
639 also warns about classic division for float and complex arguments
640 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
641 new division by default, but only in the __main__ module. You can
642 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
643 __main__ module new division, and warns about classic division
644 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000645
Tim Petersbdee63f2001-09-02 03:40:59 +0000646- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000647 long, float, str, unicode, and tuple. (The types complex, list and
648 dictionary can also be subclassed; this was introduced earlier.)
649 Note that restrictions apply when subclassing immutable built-in
650 types: you can only affect the value of the instance by overloading
651 __new__. You can add mutable attributes, and the subclass instances
652 will have a __dict__ attribute, but you cannot change the "value"
653 (as implemented by the base class) of an immutable subclass instance
654 once it is created.
655
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000656- The dictionary constructor now takes an optional argument, a
657 mapping-like object, and initializes the dictionary from its
658 (key, value) pairs.
659
Tim Petersbdee63f2001-09-02 03:40:59 +0000660- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000661 "cooperative super calls" in a multiple inheritance setting. For an
662 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
663
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000664- A new built-in type, property, has been added. This enables the
665 creation of "properties". These are attributes implemented by
666 getter and setter functions (or only one of these for read-only or
667 write-only attributes), without the need to override __getattr__.
668 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000669
Tim Petersbdee63f2001-09-02 03:40:59 +0000670- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000671 liberalized, to allow leading zeroes. Examples of literals now
672 legal that were SyntaxErrors before:
673
674 00.0 0e3 0100j 07.5 00000000000000000008.
675
Tim Petersbdee63f2001-09-02 03:40:59 +0000676- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000677 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
678
Tim Petersedc99312001-08-22 21:36:50 +0000679Library
680
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000681- telnetlib includes symbolic names for the options, and support for
682 setting an option negotiation callback.
683
Tim Petersa40c7932001-09-05 22:36:56 +0000684- The new C standard no longer requires that math libraries set errno to
685 ERANGE on overflow. For platform libraries that exploit this new
686 freedom, Python's overflow-checking was wholly broken. A new overflow-
687 checking scheme attempts to repair that, but may not be reliable on all
688 platforms (C doesn't seem to provide anything both useful and portable
689 in this area anymore).
690
Martin v. Löwis44f86962001-09-05 13:44:54 +0000691- Asynchronous timeout actions are available through the new class
692 threading.Timer.
693
Tim Peters78526162001-09-05 00:53:45 +0000694- math.log and math.log10 now return sensible results for even huge
695 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
696
Tim Petersbdee63f2001-09-02 03:40:59 +0000697- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000698 currently held. See the docs for the imp module.
699
Tim Petersbdee63f2001-09-02 03:40:59 +0000700- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000701 dumps containing ints written on platforms where Python ints are 8 bytes.
702 When read on a box where Python ints are 4 bytes, such values are
703 converted to Python longs.
704
Tim Petersbdee63f2001-09-02 03:40:59 +0000705- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000706 code objects is no longer allowed. This plugs a security hole.
707
Steve Purcell6091cd62001-09-06 16:05:17 +0000708- unittest.TestResult instances no longer store references to tracebacks
709 generated by test failures. This prevents unexpected dangling references
710 to objects that should be garbage collected between tests.
711
Tim Petersedc99312001-08-22 21:36:50 +0000712Tools
713
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000714- Tools/scripts/fixdiv.py has been added which can be used to fix
715 division operators as per PEP 238.
716
Tim Petersedc99312001-08-22 21:36:50 +0000717Build
718
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000719- If you are an adventurous person using Mac OS X you may want to look at
720 Mac/OSX. There is a Makefile there that will build Python as a real Mac
721 application, which can be used for experimenting with Carbon or Cocoa.
722 Discussion of this on pythonmac-sig, please.
723
Tim Peters7eea37e2001-09-04 22:08:56 +0000724C API
725
726- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000727
Tim Peters9fffa3e2001-09-04 05:14:19 +0000728- Note that PyLong_AsDouble can fail! This has always been true, but no
729 callers checked for it. It's more likely to fail now, because overflow
730 errors are properly detected now. The proper way to check:
731
732 double x = PyLong_AsDouble(some_long_object);
733 if (x == -1.0 && PyErr_Occurred()) {
734 /* The conversion failed. */
735 }
736
Tim Petersbdee63f2001-09-02 03:40:59 +0000737- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000738 compile but will not participate in GC. To upgrade an extension
739 module:
740
741 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000742
Neil Schemenauer4042c692001-08-30 15:38:01 +0000743 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
744 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000745
Neil Schemenauer4042c692001-08-30 15:38:01 +0000746 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
747 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000748
Neil Schemenauer4042c692001-08-30 15:38:01 +0000749 - remove PyGC_HEAD_SIZE from object size calculations
750
751 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
752
Tim Petersbdee63f2001-09-02 03:40:59 +0000753- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000754 These can be used safely to construct string objects from a
755 sprintf-style format string (similar to the format string supported
756 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000757
Tim Petersedc99312001-08-22 21:36:50 +0000758New platforms
759
Tim Petersb7da0902001-09-02 23:01:43 +0000760- Stephen Hansen contributed patches sufficient to get a clean compile
761 under Borland C (Windows), but he reports problems running it and ran
762 out of time to complete the port. Volunteers? Expect a MemoryError
763 when importing the types module; this is probably shallow, and
764 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000765
Tim Petersedc99312001-08-22 21:36:50 +0000766Tests
767
768Windows
769
Tim Peters6e13a562001-09-06 00:32:15 +0000770- Large file support is now enabled on Win32 platforms as well as on
771 Win64. This means that, for example, you can use f.tell() and f.seek()
772 to manipulate files larger than 2 gigabytes (provided you have enough
773 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000774 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
775 filesize limit, and large file support makes no difference there.
776 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
777 NTFS has no practical limit on file size, and files of any size can be
778 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000779
Tim Petersbdee63f2001-09-02 03:40:59 +0000780- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000781 points to command.com (patch from Brian Quinlan).
782
Tim Petersedc99312001-08-22 21:36:50 +0000783
Tim Peters20f51a72001-07-21 02:31:40 +0000784What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000785Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000786===========================
787
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000788Build
789
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000790- Tim Peters developed a brand new Windows installer using Wise 8.1,
791 generously donated to us by Wise Solutions.
792
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000793- configure supports a new option --enable-unicode, with the values
794 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
795 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000796
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000797- A new configure option --enable-framework builds a Mac OS X framework,
798 which "make frameworkinstall" will install. This provides a starting
799 point for more mac-like functionality, join pythonmac-sig@python.org
800 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000801
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000802- The NeXT platform is no longer supported.
803
804- The `new' module is now statically linked.
805
Tim Peters0afb6092001-08-15 06:06:44 +0000806Tools
807
808- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000809 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000810 the module docstring for details.
811
Tim Peters20f51a72001-07-21 02:31:40 +0000812Tests
813
Tim Peters5e824c32001-08-12 22:25:01 +0000814- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000815 platforms, allowing to give clearer test result output. regrtest
816 also has optional --use/-u switch to run normally disabled tests
817 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000818
Tim Peters20f51a72001-07-21 02:31:40 +0000819- Several new tests in the standard test suite, with special thanks to
820 Nick Mathewson.
821
822Core
823
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000824- The floor division operator // has been added as outlined in PEP
825 238. The / operator still provides classic division (and will until
826 Python 3.0) unless "from __future__ import division" is included, in
827 which case the / operator will provide true division. The operator
828 module provides truediv() and floordiv() functions. Augmented
829 assignment variants are included, as are the equivalent overloadable
830 methods and C API methods. See the PEP for a full discussion:
831 <http://python.sf.net/peps/pep-0238.html>
832
Tim Peters6cd6a822001-08-17 22:11:27 +0000833- Future statements are now effective in simulated interactive shells
834 (like IDLE). This should "just work" by magic, but read Michael
835 Hudson's "Future statements in simulated shells" PEP 264 for full
836 details: <http://python.sf.net/peps/pep-0264.html>.
837
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000838- The type/class unification (PEP 252-253) was integrated into the
839 trunk and is not so tentative any more (the exact specification of
840 some features is still tentative). A lot of work has done on fixing
841 bugs and adding robustness and features (performance still has to
842 come a long way).
843
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000844- Warnings about a mismatch in the Python API during extension import
845 now use the Python warning framework (which makes it possible to
846 write filters for these warnings).
847
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000848- A function's __dict__ (aka func_dict) will now always be a
849 dictionary. It used to be possible to delete it or set it to None,
850 but now both actions raise TypeErrors. It is still legal to set it
851 to a dictionary object. Getting func.__dict__ before any attributes
852 have been assigned now returns an empty dictionary instead of None.
853
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000854- A new command line option, -E, was added which disables the use of
855 all environment variables, or at least those that are specifically
856 significant to Python. Usually those have a name starting with
857 "PYTHON". This was used to fix a problem where the tests fail if
858 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
859 older distribution.
860
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000861Library
862
Tim Peters5e824c32001-08-12 22:25:01 +0000863- New class Differ and new functions ndiff() and restore() in difflib.py.
864 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000865 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000866
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000867- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
868 value using the minimal quoting required for the value; more
869 reliable than using xml.sax.saxutils.escape() for attribute values.
870
871- Readline completion support for cmd.Cmd was added.
872
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000873- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
874
875- Added function threading.BoundedSemaphore()
876
877- Added Ka-Ping Yee's cgitb.py module.
878
879- The `new' module now exposes the CO_xxx flags.
880
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000881New platforms
882
883C API
884
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000885- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
886 which provide a cross-platform implementations for the
887 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
888 the standard sprintf() and vsprintf() C lib APIs, these versions
889 apply bounds checking on the used buffer which enhances protection
890 against buffer overruns.
891
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000892- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000893 and extensions using different Unicode widths is rendered next to
894 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000895 will result in an ImportError. Unicode extensions writers must make
896 sure to check the Unicode width compatibility in their extensions by
897 using at least one of the mangled Unicode APIs in the extension.
898
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000899- Two new flags METH_NOARGS and METH_O are available in method definition
900 tables to simplify implementation of methods with no arguments and a
901 single untyped argument. Calling such methods is more efficient than
902 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
903 deprecated.
904
Tim Petersc1731372001-08-04 08:12:36 +0000905Windows
906
907- "import module" now compiles module.pyw if it exists and nothing else
908 relevant is found.
909
Tim Peters20f51a72001-07-21 02:31:40 +0000910
Guido van Rossum55a78992001-07-17 17:22:32 +0000911What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000912Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000913===========================
914
915Core
Tim Petersa814db52001-05-14 07:05:58 +0000916
Tim Peters6d6c1a32001-08-02 04:15:00 +0000917- TENTATIVELY, a large amount of code implementing much of what's
918 described in PEP 252 (Making Types Look More Like Classes) and PEP
919 253 (Subtyping Built-in Types) was added. This will be released
920 with Python 2.2a1. Documentation will be provided separately
921 through http://www.python.org/2.2/. The purpose of releasing this
922 with Python 2.2a1 is to test backwards compatibility. It is
923 possible, though not likely, that a decision is made not to release
924 this code as part of 2.2 final, if any serious backwards
925 incompapatibilities are found during alpha testing that cannot be
926 repaired.
927
Guido van Rossum55a78992001-07-17 17:22:32 +0000928- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000929 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000930 more 'yield' statements. See PEP 255. Since this adds a new
931 keyword to the language, this feature must be enabled by including a
932 future statement: "from __future__ import generators" (see PEP 236).
933 Generators will become a standard feature in a future release
934 (probably 2.3). Without this future statement, 'yield' remains an
935 ordinary identifier, but a warning is issued each time it is used.
936 (These warnings currently don't conform to the warnings framework of
937 PEP 230; we intend to fix this in 2.2a2.)
938
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000939- The UTF-16 codec was modified to be more RFC compliant. It will now
940 only remove BOM characters at the start of the string and then
941 only if running in native mode (UTF-16-LE and -BE won't remove a
942 leading BMO character).
943
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000944- Strings now have a new method .decode() to complement the already
945 existing .encode() method. These two methods provide direct access
946 to the corresponding decoders and encoders of the registered codecs.
947
948 To enhance the usability of the .encode() method, the special
949 casing of Unicode object return values was dropped (Unicode objects
950 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000951
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000952 Both methods will now return whatever the codec in charge of the
953 requested encoding returns as object, e.g. Unicode codecs will
954 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
955 will return u"äöü"). This enables codec writer to create codecs
956 for various simple to use conversions.
957
958 New codecs were added to demonstrate these new features (the .encode()
959 and .decode() columns indicate the type of the returned objects):
960
961 Name | .encode() | .decode() | Description
962 ----------------------------------------------------------------------
963 uu | string | string | UU codec (e.g. for email)
964 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000965 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000966 zlib | string | string | zlib compression
967 hex | string | string | 2-byte hex codec
968 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
969
Mark Hammond2a0af792001-05-14 03:09:36 +0000970- Some operating systems now support the concept of a default Unicode
971 encoding for file system operations. Notably, Windows supports 'mbcs'
972 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000973 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000974 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000975
976 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000977 functions that return filenames (such as os.listdir()) to return Python
978 string objects pre-encoded using the default file system encoding for
979 the platform. As this encoding is likely to be different from Python's
980 default encoding, converting this name to a Unicode object before passing
981 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000982 would attempt to use its default encoding (generally ASCII) rather than
983 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000984
Tim Petersa814db52001-05-14 07:05:58 +0000985 In general, this change simply removes surprises when working with
986 Unicode and the file system, making these operations work as you expect,
987 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000988 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000989
Tim Peters61dff2b2001-05-08 15:43:37 +0000990- Float (and complex) literals in source code were evaluated to full
991 precision only when running from a .py file; the same code loaded from a
992 .pyc (or .pyo) file could suffer numeric differences starting at about the
993 12th significant decimal digit. For example, on a machine with IEEE-754
994 floating arithmetic,
995
996 x = 9007199254740992.0
997 print long(x)
998
999 printed 9007199254740992 if run directly from .py, but 9007199254740000
1000 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1001 str(float) instead of repr(float) when building code objects. marshal
1002 now uses repr(float) instead, which should reproduce floats to full
1003 machine precision (assuming the platform C float<->string I/O conversion
1004 functions are of good quality).
1005
1006 This may cause floating-point results to change in some cases, and
1007 usually for the better, but may also cause numerically unstable
1008 algorithms to break.
1009
Tim Peters2f228e72001-05-13 00:19:31 +00001010- The implementation of dicts suffers fewer collisions, which has speed
1011 benefits. However, the order in which dict entries appear in dict.keys(),
1012 dict.values() and dict.items() may differ from previous releases for a
1013 given dict. Nothing is defined about this order, so no program should
1014 rely on it. Nevertheless, it's easy to write test cases that rely on the
1015 order by accident, typically because of printing the str() or repr() of a
1016 dict to an "expected results" file. See Lib/test/test_support.py's new
1017 sortdict(dict) function for a simple way to display a dict in sorted
1018 order.
1019
Tim Peters7a3bfc32001-06-12 01:22:22 +00001020- Many other small changes to dicts were made, resulting in faster
1021 operation along the most common code paths.
1022
Guido van Rossum10315822001-05-01 20:54:30 +00001023- Dictionary objects now support the "in" operator: "x in dict" means
1024 the same as dict.has_key(x).
1025
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001026- The update() method of dictionaries now accepts generic mapping
1027 objects. Specifically the argument object must support the .keys()
1028 and __getitem__() methods. This allows you to say, for example,
1029 {}.update(UserDict())
1030
Guido van Rossum10315822001-05-01 20:54:30 +00001031- Iterators were added; this is a generalized way of providing values
1032 to a for loop. See PEP 234. There's a new built-in function iter()
1033 to return an iterator. There's a new protocol to get the next value
1034 from an iterator using the next() method (in Python) or the
1035 tp_iternext slot (in C). There's a new protocol to get iterators
1036 using the __iter__() method (in Python) or the tp_iter slot (in C).
1037 Iterating (i.e. a for loop) over a dictionary generates its keys.
1038 Iterating over a file generates its lines.
1039
Tim Petersf553f892001-05-01 20:45:31 +00001040- The following functions were generalized to work nicely with iterator
1041 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001042 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001043 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1044 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001045 join() method of strings
1046 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001047 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1048 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001049 right-hand side of assignment statements with multiple targets, such as
1050 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001051
Tim Petersd85e1022001-05-11 21:51:48 +00001052- Accessing module attributes is significantly faster (for example,
1053 random.random or os.path or yourPythonModule.yourAttribute).
1054
Tim Peterse63415e2001-05-08 04:38:29 +00001055- Comparing dictionary objects via == and != is faster, and now works even
1056 if the keys and values don't support comparisons other than ==.
1057
Tim Peters95bf9392001-05-10 08:32:44 +00001058- Comparing dictionaries in ways other than == and != is slower: there were
1059 insecurities in the dict comparison implementation that could cause Python
1060 to crash if the element comparison routines for the dict keys and/or
1061 values mutated the dicts. Making the code bulletproof slowed it down.
1062
Tim Peterseb28ef22001-06-02 05:27:19 +00001063- Collisions in dicts are resolved via a new approach, which can help
1064 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001065 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001066 faster now. Thanks to Christian Tismer for pointing out the cause and
1067 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001068
Tim Peters52e155e2001-06-16 05:42:57 +00001069- repr() is much faster for large containers (dict, list, tuple).
1070
1071
Tim Petersa814db52001-05-14 07:05:58 +00001072Library
1073
Fred Drake960fdf92001-07-20 18:38:26 +00001074- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1075 were added to the string module. These a locale-indenpendent
1076 constants, unlike letters, lowercase, and uppercase. These are now
1077 use in appropriate locations in the standard library.
1078
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001079- The flags used in dlopen calls can now be configured using
1080 sys.setdlopenflags and queried using sys.getdlopenflags.
1081
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001082- Fredrik Lundh's xmlrpclib is now a standard library module. This
1083 provides full client-side XML-RPC support. In addition,
1084 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1085 one asyncore-based). Thanks to Eric Raymond for the documentation.
1086
Guido van Rossum643d3912001-07-05 14:46:25 +00001087- The xrange() object is simplified: it no longer supports slicing,
1088 repetition, comparisons, efficient 'in' checking, the tolist()
1089 method, or the start, stop and step attributes. See PEP 260.
1090
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001091- A new function fnmatch.filter to filter lists of file names was added.
1092
Barry Warsawffd674d2001-05-22 16:00:10 +00001093- calendar.py uses month and day names based on the current locale.
1094
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001095- strop is now *really* obsolete (this was announced before with 1.6),
1096 and issues DeprecationWarning when used (except for the four items
1097 that are still imported into string.py).
1098
Tim Petersa814db52001-05-14 07:05:58 +00001099- Cookie.py now sorts key+value pairs by key in output strings.
1100
1101- pprint.isrecursive(object) didn't correctly identify recursive objects.
1102 Now it does.
1103
Tim Peters95b3f782001-05-14 18:39:41 +00001104- pprint functions now much faster for large containers (tuple, list, dict).
1105
Tim Peters7b9542a2001-06-10 23:40:19 +00001106- New 'q' and 'Q' format codes in the struct module, corresponding to C
1107 types "long long" and "unsigned long long" (on Windows, __int64). In
1108 native mode, these can be used only when the platform C compiler supports
1109 these types (when HAVE_LONG_LONG is #define'd by the Python config
1110 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001111 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1112 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001113
Guido van Rossum83213cc2001-06-12 16:48:52 +00001114- The site module installs a new built-in function 'help' that invokes
1115 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1116 it displays a message reminding the user to use 'help()' or
1117 'help(object)'.
1118
Tim Petersa814db52001-05-14 07:05:58 +00001119Tests
1120
1121- New test_mutants.py runs dict comparisons where the key and value
1122 comparison operators mutute the dicts randomly during comparison. This
1123 rapidly causes Python to crash under earlier releases (not for the faint
1124 of heart: it can also cause Win9x to freeze or reboot!).
1125
1126- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001127 pprint.isreadable() return sensible results. Also verifies that simple
1128 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001129
Tim Peters4324aa32001-05-28 22:30:08 +00001130C API
1131
1132- Removed the unused last_is_sticky argument from the internal
1133 _PyTuple_Resize(). If this affects you, you were cheating.
1134
1135
Guido van Rossum55a78992001-07-17 17:22:32 +00001136======================================================================
1137
1138
Guido van Rossumffe13be2001-04-16 18:46:45 +00001139What's New in Python 2.1 (final)?
1140=================================
1141
1142We only changed a few things since the last release candidate, all in
1143Python library code:
1144
1145- A bug in the locale module was fixed that affected locales which
1146 define no grouping for numeric formatting.
1147
1148- A few bugs in the weakref module's implementations of weak
1149 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1150 and the test suite was updated to check for these bugs.
1151
1152- An old bug in the os.path.walk() function (introduced in Python
1153 2.0!) was fixed: a non-existent file would cause an exception
1154 instead of being ignored.
1155
1156- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1157 PyChecker.
1158
1159
Guido van Rossum5b08f132001-04-16 02:05:23 +00001160What's New in Python 2.1c2?
1161===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001162
Guido van Rossum5b08f132001-04-16 02:05:23 +00001163A flurry of small changes, and one showstopper fixed in the nick of
1164time made it necessary to release another release candidate. The list
1165here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001166
Guido van Rossum5b08f132001-04-16 02:05:23 +00001167Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001168
Guido van Rossum5b08f132001-04-16 02:05:23 +00001169- Tim discovered a nasty bug in the dictionary code, caused by
1170 PyDict_Next() calling dict_resize(), and the GC code's use of
1171 PyDict_Next() violating an assumption in dict_items(). This was
1172 fixed with considerable amounts of band-aid, but the net effect is a
1173 saner and more robust implementation.
1174
1175- Made a bunch of symbols static that were accidentally global.
1176
1177Build and Ports
1178
1179- The setup.py script didn't check for a new enough version of zlib
1180 (1.1.3 is needed). Now it does.
1181
1182- Changed "make clean" target to also remove shared libraries.
1183
1184- Added a more general warning about the SGI Irix optimizer to README.
1185
1186Library
1187
1188- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1189 omitted the slash between host and file.html.
1190
1191- The mailbox module's _Mailbox class contained a completely broken
1192 and undocumented seek() method. Ripped it out.
1193
1194- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1195 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1196
1197- Fixed a few last-minute bugs in unittest.
1198
1199Extensions
1200
1201- Reverted the patch to the OpenSSL code in socketmodule.c to support
1202 RAND_status() and the EGD, and the subsequent patch that tried to
1203 fix it for pre-0.9.5 versions; the problem with the patch is that on
1204 some systems it issues a warning whenever socket is imported, and
1205 that's unacceptable.
1206
1207Tests
1208
1209- Fixed the pickle tests to work with "import test.test_pickle".
1210
1211- Tweaked test_locale.py to actually run the test Windows.
1212
1213- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1214 not "wb" (which is not a valid mode at all).
1215
1216- Fix pstats browser crashes. Import readline if it exists to make
1217 the user interface nicer.
1218
1219- Add "import thread" to the top of test modules that import the
1220 threading module (test_asynchat and test_threadedtempfile). This
1221 prevents test failures caused by a broken threading module resulting
1222 from a previously caught failed import.
1223
1224- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1225 needed on some platforms (e.g. Solaris 8) when the tests are run
1226 twice in succession.
1227
1228- Skip rather than fail test_sunaudiodev if no audio device is found.
1229
1230
1231What's New in Python 2.1c1?
1232===========================
1233
1234This list was significantly updated when 2.1c2 was released; the 2.1c1
1235release didn't mention most changes that were actually part of 2.1c1:
1236
1237Legal
1238
1239- Copyright was assigned to the Python Software Foundation (PSF) and a
1240 PSF license (very similar to the CNRI license) was added.
1241
1242- The CNRI copyright notice was updated to include 2001.
1243
1244Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001245
Guido van Rossumc9932722001-04-12 02:31:27 +00001246- After a public outcry, assignment to __debug__ is no longer illegal;
1247 instead, a warning is issued. It will become illegal in 2.2.
1248
Guido van Rossum5b08f132001-04-16 02:05:23 +00001249- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1250 "%#x" now always prepends "0x", even if the value is zero.
1251
1252- Fixed some nits in the bytecode compiler.
1253
1254- Fixed core dumps when calling certain kinds of non-functions.
1255
1256- Fixed various core dumps caused by reference count bugs.
1257
1258Build and Ports
1259
1260- Use INSTALL_SCRIPT to install script files.
1261
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001262- New port: SCO Unixware 7, by Billy G. Allie.
1263
Guido van Rossum5b08f132001-04-16 02:05:23 +00001264- Updated RISCOS port.
1265
1266- Updated BeOS port and notes.
1267
1268- Various other porting problems resolved.
1269
1270Library
1271
1272- The TERMIOS and SOCKET modules are now truly obsolete and
1273 unnecessary. Their symbols are incorporated in the termios and
1274 socket modules.
1275
1276- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1277 better tests for pickling.
1278
1279- threading: make Condition.wait() robust against KeyboardInterrupt.
1280
1281- zipfile: add support to zipfile to support opening an archive
1282 represented by an open file rather than a file name. Fix bug where
1283 the archive was not properly closed. Fixed a bug in this bugfix
1284 where flush() was called for a read-only file.
1285
1286- imputil: added an uninstall() method to the ImportManager.
1287
1288- Canvas: fixed bugs in lower() and tkraise() methods.
1289
1290- SocketServer: API change (added overridable close_request() method)
1291 so that the TCP server can explicitly close the request.
1292
1293- pstats: Eric Raymond added a simple interactive statistics browser,
1294 invoked when the module is run as a script.
1295
1296- locale: fixed a problem in format().
1297
1298- webbrowser: made it work when the BROWSER environment variable has a
1299 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1300 KDE 2. Fixed some other nits.
1301
1302- unittest: changes to allow using a different exception than
1303 AssertionError, and added a few more function aliases. Some other
1304 small changes.
1305
1306- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1307
1308- asynchat: fixed a critical bug in asynchat that slipped through the
1309 2.1b2 release. Fixed another rare bug.
1310
1311- Fix some unqualified except: clauses (always a bad code example).
1312
1313XML
1314
1315- pyexpat: new API get_version_string().
1316
1317- Fixed some minidom bugs.
1318
1319Extensions
1320
1321- Fixed a core dump in _weakref. Removed the weakref.mapping()
1322 function (it adds nothing to the API).
1323
1324- Rationalized the use of header files in the readline module, to make
1325 it compile (albeit with some warnings) with the very recent readline
1326 4.2, without breaking for earlier versions.
1327
1328- Hopefully fixed a buffering problem in linuxaudiodev.
1329
1330- Attempted a fix to make the OpenSSL support in the socket module
1331 work again with pre-0.9.5 versions of OpenSSL.
1332
1333Tests
1334
1335- Added a test case for asynchat and asyncore.
1336
1337- Removed coupling between tests where one test failing could break
1338 another.
1339
1340Tools
1341
1342- Ping added an interactive help browser to pydoc, fixed some nits
1343 in the rest of the pydoc code, and added some features to his
1344 inspect module.
1345
1346- An updated python-mode.el version 4.1 which integrates Ken
1347 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1348 much nicer in XEmacs and Emacs. When stepping through your program
1349 with pdb, in either the shell window or the *Python* window, the
1350 source file and line will be tracked by an arrow. Very cool!
1351
1352- IDLE: syntax warnings in interactive mode are changed into errors.
1353
1354- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001355 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001356
1357- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001358
Barry Warsaw11e89c72001-04-11 20:37:57 +00001359
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001360What's New in Python 2.1 beta 2?
1361================================
1362
Guido van Rossum053ae352001-03-22 14:17:21 +00001363(Unlisted are many fixed bugs, more documentation, etc.)
1364
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001365Core language, builtins, and interpreter
1366
Guido van Rossum053ae352001-03-22 14:17:21 +00001367- The nested scopes work (enabled by "from __future__ import
1368 nested_scopes") is completed; in particular, the future now extends
1369 into code executed through exec, eval() and execfile(), and into the
1370 interactive interpreter.
1371
1372- When calling a base class method (e.g. BaseClass.__init__(self)),
1373 this is now allowed even if self is not strictly spoken a class
1374 instance (e.g. when using metaclasses or the Don Beaudry hook).
1375
1376- Slice objects are now comparable but not hashable; this prevents
1377 dict[:] from being accepted but meaningless.
1378
1379- Complex division is now calculated using less braindead algorithms.
1380 This doesn't change semantics except it's more likely to give useful
1381 results in extreme cases. Complex repr() now uses full precision
1382 like float repr().
1383
1384- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1385
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001386- It is illegal to assign to the name __debug__, which is set when the
1387 interpreter starts. It is effectively a compile-time constant.
1388
1389- A warning will be issued if a global statement for a variable
1390 follows a use or assignment of that variable.
1391
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001392Standard library
1393
Guido van Rossum053ae352001-03-22 14:17:21 +00001394- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1395 inspired by JUnit), is now part of the standard library. You now
1396 have a choice of two testing frameworks: unittest requires you to
1397 write testcases as separate code, doctest gathers them from
1398 docstrings. Both approaches have their advantages and
1399 disadvantages.
1400
1401- A new module Tix was added, which wraps the Tix extension library
1402 for Tk. With that module, it is not necessary to statically link
1403 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1404 require" command. See Demo/tix/.
1405
1406- tzparse.py is now obsolete.
1407
1408- In gzip.py, the seek() and tell() methods are removed -- they were
1409 non-functional anyway, and it's better if callers can test for their
1410 existence with hasattr().
1411
1412Python/C API
1413
1414- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1415 that's already in the dictionary during a PyDict_Next() iteration.
1416 This used to fail occasionally when a dictionary resize operation
1417 could be triggered that would rehash all the keys. All other
1418 modifications to the dictionary are still off-limits during a
1419 PyDict_Next() iteration!
1420
1421- New extended APIs related to passing compiler variables around.
1422
1423- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1424 implement isinstance() and issubclass().
1425
1426- Py_BuildValue() now has a "D" conversion to create a Python complex
1427 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001428
Fred Drake4e262a92001-03-22 18:26:47 +00001429- Extensions types which support weak references must now set the
1430 field allocated for the weak reference machinery to NULL themselves;
1431 this is done to avoid the cost of checking each object for having a
1432 weakly referencable type in PyObject_INIT(), since most types are
1433 not weakly referencable.
1434
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001435- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1436 free variables and cell variables to and from the frame's f_locals.
1437
1438- Variants of several functions defined in pythonrun.h have been added
1439 to support the nested_scopes future statement. The variants all end
1440 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1441 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1442 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001443 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001444
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001445Distutils
1446
1447- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1448 into the release tree.
1449
Tim Peters0e57abf2001-05-02 07:39:38 +00001450- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001451 (an uninstaller, more customization of the installer's display)
1452
1453- from Jack Jansen: added Mac-specific code to generate a dialog for
1454 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001455 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001456 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001457
1458- added 'platforms' and 'keywords' to the set of metadata that can be
1459 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001460
1461- applied patches from Jason Tishler to make the compiler class work with
1462 Cygwin.
1463
1464
Tim Peters2fe289a2001-03-01 22:19:38 +00001465What's New in Python 2.1 beta 1?
1466================================
Tim Petersd66595f2001-02-04 03:09:53 +00001467
1468Core language, builtins, and interpreter
1469
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001470- Following an outcry from the community about the amount of code
1471 broken by the nested scopes feature introduced in 2.1a2, we decided
1472 to make this feature optional, and to wait until Python 2.2 (or at
1473 least 6 months) to make it standard. The option can be enabled on a
1474 per-module basis by adding "from __future__ import nested_scopes" at
1475 the beginning of a module (before any other statements, but after
1476 comments and an optional docstring). See PEP 236 (Back to the
1477 __future__) for a description of the __future__ statement. PEP 227
1478 (Statically Nested Scopes) has been updated to reflect this change,
1479 and to clarify the semantics in a number of endcases.
1480
1481- The nested scopes code, when enabled, has been hardened, and most
1482 bugs and memory leaks in it have been fixed.
1483
1484- Compile-time warnings are now generated for a number of conditions
1485 that will break or change in meaning when nested scopes are enabled:
1486
1487 - Using "from...import *" or "exec" without in-clause in a function
1488 scope that also defines a lambda or nested function with one or
1489 more free (non-local) variables. The presence of the import* or
1490 bare exec makes it impossible for the compiler to determine the
1491 exact set of local variables in the outer scope, which makes it
1492 impossible to determine the bindings for free variables in the
1493 inner scope. To avoid the warning about import *, change it into
1494 an import of explicitly name object, or move the import* statement
1495 to the global scope; to avoid the warning about bare exec, use
1496 exec...in... (a good idea anyway -- there's a possibility that
1497 bare exec will be deprecated in the future).
1498
1499 - Use of a global variable in a nested scope with the same name as a
1500 local variable in a surrounding scope. This will change in
1501 meaning with nested scopes: the name in the inner scope will
1502 reference the variable in the outer scope rather than the global
1503 of the same name. To avoid the warning, either rename the outer
1504 variable, or use a global statement in the inner function.
1505
Neil Schemenauera35c6882001-02-27 04:45:05 +00001506- An optional object allocator has been included. This allocator is
1507 optimized for Python objects and should be faster and use less memory
1508 than the standard system allocator. It is not enabled by default
1509 because of possible thread safety problems. The allocator is only
1510 protected by the Python interpreter lock and it is possible that some
1511 extension modules require a thread safe allocator. The object
1512 allocator can be enabled by providing the "--with-pymalloc" option to
1513 configure.
1514
Tim Petersd66595f2001-02-04 03:09:53 +00001515Standard library
1516
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001517- pyexpat now detects the expat version if expat.h defines it. A
1518 number of additional handlers are provided, which are only available
1519 since expat 1.95. In addition, the methods SetParamEntityParsing and
1520 GetInputContext of Parser objects are available with 1.95.x
1521 only. Parser objects now provide the ordered_attributes and
1522 specified_attributes attributes. A new module expat.model was added,
1523 which offers a number of additional constants if 1.95.x is used.
1524
1525- xml.dom offers the new functions registerDOMImplementation and
1526 getDOMImplementation.
1527
1528- xml.dom.minidom offers a toprettyxml method. A number of DOM
1529 conformance issues have been resolved. In particular, Element now
1530 has an hasAttributes method, and the handling of namespaces was
1531 improved.
1532
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001533- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1534 getting information about live Python code, and pydoc.py, a module
1535 for interactively converting docstrings to HTML or text.
1536 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001537 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001538 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1539 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001540
Tim Peters1eff7962001-03-01 02:31:33 +00001541- New library module difflib.py, primarily packaging the SequenceMatcher
1542 class at the heart of the popular ndiff.py file-comparison tool.
1543
1544- doctest.py (a framework for verifying Python code examples in docstrings)
1545 is now part of the std library.
1546
Tim Petersd66595f2001-02-04 03:09:53 +00001547Windows changes
1548
Guido van Rossume3955a82001-03-02 14:05:59 +00001549- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1550 small GUI that lets you browse the module docstrings using your
1551 default web browser.
1552
Tim Peters1eff7962001-03-01 02:31:33 +00001553- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1554 Platforms) is implemented. See
1555
1556 http://python.sourceforge.net/peps/pep-0235.html
1557
1558 for full details, especially the "Current Lower-Left Semantics" section.
1559 The new Windows import rules are simpler than before:
1560
1561 A. If the PYTHONCASEOK environment variable exists, same as
1562 before: silently accept the first case-insensitive match of any
1563 kind; raise ImportError if none found.
1564
1565 B. Else search sys.path for the first case-sensitive match; raise
1566 ImportError if none found.
1567
1568 The same rules have been implented on other platforms with case-
1569 insensitive but case-preserving filesystems too (including Cygwin, and
1570 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001571
Tim Peters25a9ce32001-02-19 07:06:36 +00001572- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1573 what it's supposed to do (and does do under NT and 2000) via direct
1574 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001575 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001576 all Win9x systems before.
1577
Tim Peters1eff7962001-03-01 02:31:33 +00001578- Build: Subproject _test (effectively) renamed to _testcapi.
1579
Tim Peters2fe289a2001-03-01 22:19:38 +00001580New platforms
1581
1582- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1583 Thanks to Steven Majewski!
1584
1585- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1586 Tishler!
1587
Guido van Rossum9089b272001-03-02 06:49:50 +00001588- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1589 Schwertberger! See RISCOS/README for more information -- it seems
1590 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001591 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001592
Tim Peters25a9ce32001-02-19 07:06:36 +00001593
Tim Petersd7b5e882001-01-25 03:36:26 +00001594What's New in Python 2.1 alpha 2?
1595=================================
Tim Peters40ead762001-01-27 05:35:26 +00001596
Tim Petersd7b5e882001-01-25 03:36:26 +00001597Core language, builtins, and interpreter
1598
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001599- Scopes nest. If a name is used in a function or class, but is not
1600 local, the definition in the nearest enclosing function scope will
1601 be used. One consequence of this change is that lambda statements
1602 could reference variables in the namespaces where the lambda is
1603 defined. In some unusual cases, this change will break code.
1604
1605 In all previous version of Python, names were resolved in exactly
1606 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001607 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001608 function A is defined within a function B, the names bound in B are
1609 not visible in A. The new rules make names bound in B visible in A,
1610 unless A contains a name binding that hides the binding in B.
1611
1612 Section 4.1 of the reference manual describes the new scoping rules
1613 in detail. The test script in Lib/test/test_scope.py demonstrates
1614 some of the effects of the change.
1615
1616 The new rules will cause existing code to break if it defines nested
1617 functions where an outer function has local variables with the same
1618 name as globals or builtins used by the inner function. Example:
1619
1620 def munge(str):
1621 def helper(x):
1622 return str(x)
1623 if type(str) != type(''):
1624 str = helper(str)
1625 return str.strip()
1626
1627 Under the old rules, the name str in helper() is bound to the
1628 builtin function str(). Under the new rules, it will be bound to
1629 the argument named str and an error will occur when helper() is
1630 called.
1631
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001632- The compiler will report a SyntaxError if "from ... import *" occurs
1633 in a function or class scope. The language reference has documented
1634 that this case is illegal, but the compiler never checked for it.
1635 The recent introduction of nested scope makes the meaning of this
1636 form of name binding ambiguous. In a future release, the compiler
1637 may allow this form when there is no possibility of ambiguity.
1638
Tim Peters40ead762001-01-27 05:35:26 +00001639- repr(string) is easier to read, now using hex escapes instead of octal,
1640 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1641
1642 >>> "\texample \r\n" + chr(0) + chr(255)
1643 '\texample \r\n\x00\xff' # in 2.1
1644 '\011example \015\012\000\377' # in 2.0
1645
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001646- Functions are now compared and hashed by identity, not by value, since
1647 the func_code attribute is writable.
1648
Fred Drakefb9d7122001-02-01 20:00:40 +00001649- Weak references (PEP 205) have been added. This involves a few
1650 changes in the core, an extension module (_weakref), and a Python
1651 module (weakref). The weakref module is the public interface. It
1652 includes support for "explicit" weak references, proxy objects, and
1653 mappings with weakly held values.
1654
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001655- A 'continue' statement can now appear in a try block within the body
1656 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001657 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001658
Tim Petersd7b5e882001-01-25 03:36:26 +00001659Standard library
1660
Barry Warsaw30dbd142001-01-31 22:14:01 +00001661- mailbox.py now has a new class, PortableUnixMailbox which is
1662 identical to UnixMailbox but uses a more portable scheme for
1663 determining From_ separators. Also, the constructors for all the
1664 classes in this module have a new optional `factory' argument, which
1665 is a callable used when new message classes must be instantiated by
1666 the next() method.
1667
Tim Petersd7b5e882001-01-25 03:36:26 +00001668- random.py is now self-contained, and offers all the functionality of
1669 the now-deprecated whrandom.py. See the docs for details. random.py
1670 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001671 and restoring the internal state of the generator; and jumpahead(n),
1672 for quickly forcing the internal state to be the same as if n calls to
1673 random() had been made. The latter is particularly useful for multi-
1674 threaded programs, creating one instance of the random.Random() class for
1675 each thread, then using .jumpahead() to force each instance to use a
1676 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001677
Tim Peters0de88fc2001-02-01 04:59:18 +00001678- random.py's seed() function is new. For bit-for-bit compatibility with
1679 prior releases, use the whseed function instead. The new seed function
1680 addresses two problems: (1) The old function couldn't produce more than
1681 about 2**24 distinct internal states; the new one about 2**45 (the best
1682 that can be done in the Wichmann-Hill generator). (2) The old function
1683 sometimes produced identical internal states when passed distinct
1684 integers, and there was no simple way to predict when that would happen;
1685 the new one guarantees to produce distinct internal states for all
1686 arguments in [0, 27814431486576L).
1687
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001688- The socket module now supports raw packets on Linux. The socket
1689 family is AF_PACKET.
1690
Tim Peters9ea17ac2001-02-02 05:57:15 +00001691- test_capi.py is a start at running tests of the Python C API. The tests
1692 are implemented by the new Modules/_testmodule.c.
1693
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001694- A new extension module, _symtable, provides provisional access to the
1695 internal symbol table used by the Python compiler. A higher-level
1696 interface will be added on top of _symtable in a future release.
1697
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001698- Removed the obsolete soundex module.
1699
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001700- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1701 the isSameNode method; NamedNodeMap the get method.
1702
1703- xml.sax.expatreader supports the lexical handler property; it
1704 generates comment, startCDATA, and endCDATA events.
1705
Tim Petersee826f82001-01-31 19:39:44 +00001706Windows changes
1707
1708- Build procedure: the zlib project is built in a different way that
1709 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001710 the zlib binary used. See PCbuild\readme.txt for details. Your old
1711 zlib-related directories can be deleted; you'll need to download fresh
1712 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001713
Tim Peters9ea17ac2001-02-02 05:57:15 +00001714- Build: New subproject _test for the benefit of test_capi.py (see above).
1715
Tim Petersb16c56f2001-02-02 21:24:51 +00001716- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1717 interface to some Python compiler internals).
1718
1719- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001720 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001721
Tim Petersa3a3a032000-11-30 05:22:44 +00001722What's New in Python 2.1 alpha 1?
1723=================================
1724
1725Core language, builtins, and interpreter
1726
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001727- There is a new Unicode companion to the PyObject_Str() API
1728 called PyObject_Unicode(). It behaves in the same way as the
1729 former, but assures that the returned value is an Unicode object
1730 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001731
Guido van Rossumf98eda02001-01-17 15:54:45 +00001732- The comparison operators support "rich comparison overloading" (PEP
1733 207). C extension types can provide a rich comparison function in
1734 the new tp_richcompare slot in the type object. The cmp() function
1735 and the C function PyObject_Compare() first try the new rich
1736 comparison operators before trying the old 3-way comparison. There
1737 is also a new C API PyObject_RichCompare() (which also falls back on
1738 the old 3-way comparison, but does not constrain the outcome of the
1739 rich comparison to a Boolean result).
1740
1741 The rich comparison function takes two objects (at least one of
1742 which is guaranteed to have the type that provided the function) and
1743 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1744 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1745 object, which may be NotImplemented (in which case the tp_compare
1746 slot function is used as a fallback, if defined).
1747
1748 Classes can overload individual comparison operators by defining one
1749 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001750 __ge__. There are no explicit "reflected argument" versions of
1751 these; instead, __lt__ and __gt__ are each other's reflection,
1752 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1753 reflection (similar at the C level). No other implications are
1754 made; in particular, Python does not assume that == is the Boolean
1755 inverse of !=, or that < is the Boolean inverse of >=. This makes
1756 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001757
1758 Classes or types that want to implement (in)equality tests but not
1759 the ordering operators (i.e. unordered types) should implement ==
1760 and !=, and raise an error for the ordering operators.
1761
Guido van Rossuma88479f2001-01-18 14:28:08 +00001762 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001763 Boolean; e.g. a matrix type might want to return a matrix of bits
1764 for A < B, giving elementwise comparisons. Such types should ensure
1765 that any interpretation of their value in a Boolean context raises
1766 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1767 at the C level) to always raise an exception.
1768
Guido van Rossuma88479f2001-01-18 14:28:08 +00001769- Complex numbers use rich comparisons to define == and != but raise
1770 an exception for <, <=, > and >=. Unfortunately, this also means
1771 that cmp() of two complex numbers raises an exception when the two
1772 numbers differ. Since it is not mathematically meaningful to compare
1773 complex numbers except for equality, I hope that this doesn't break
1774 too much code.
1775
Tim Peters3389f192001-02-18 08:48:49 +00001776- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001777 not defined by the language, other than that it's arbitrary but
1778 consistent (see the Reference Manual). An implementation detail changed
1779 in 2.1a1 such that None now compares less than any other object. Code
1780 relying on this new behavior (like code that relied on the previous
1781 behavior) does so at its own risk.
1782
Barry Warsaw573b5412001-01-15 20:43:18 +00001783- Functions and methods now support getting and setting arbitrarily
1784 named attributes (PEP 232). Functions have a new __dict__
1785 (a.k.a. func_dict) which hold the function attributes. Methods get
1786 and set attributes on their underlying im_func. It is a TypeError
1787 to set an attribute on a bound method.
1788
Guido van Rossum051e3352001-01-15 19:11:10 +00001789- The xrange() object implementation has been improved so that
1790 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1791 limitation that in this case len(xrange(sys.maxint)) can't be
1792 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1793 work fine as long as the index i doesn't actually reach 2**31.
1794 (Python uses regular ints for sequence and string indices; fixing
1795 that is much more work.)
1796
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001797- Two changes to from...import:
1798
Guido van Rossumba381232001-02-03 15:06:40 +00001799 1) "from M import X" now works even if (after loading module M)
1800 sys.modules['M'] is not a real module; it's basically a getattr()
1801 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001802
1803 2) "from M import *" now looks for M.__all__ to decide which names to
1804 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1805 filters out names starting with '_' as before. Whether or not
1806 __all__ exists, there's no restriction on the type of M.
1807
Guido van Rossumf61f1662001-01-10 20:13:55 +00001808- File objects have a new method, xreadlines(). This is the fastest
1809 way to iterate over all lines in a file:
1810
1811 for line in file.xreadlines():
1812 ...do something to line...
1813
1814 See the xreadlines module (mentioned below) for how to do this for
1815 other file-like objects.
1816
1817- Even if you don't use file.xreadlines(), you may expect a speedup on
1818 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001819 quite a bit in platform-specific ways: on systems (like Linux) that
1820 support flockfile(), getc_unlocked(), and funlockfile(), those are
1821 used by default. On systems (like Windows) without getc_unlocked(),
1822 a complicated (but still thread-safe) method using fgets() is used by
1823 default.
1824
Tim Petersd52269b2001-01-25 06:23:18 +00001825 You can force use of the fgets() method by #define'ing
1826 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001827 getc_unlocked()).
1828
Tim Petersd52269b2001-01-25 06:23:18 +00001829 You can force fgets() not to be used by #define'ing
1830 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001831 test_bufio.py fails -- and let us know if it does!).
1832
1833- In addition, the fileinput module, while still slower than the other
1834 methods on most platforms, has been sped up too, by using
1835 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001836
1837- Support for run-time warnings has been added, including a new
1838 command line option (-W) to specify the disposition of warnings.
1839 See the description of the warnings module below.
1840
1841- Extensive changes have been made to the coercion code. This mostly
1842 affects extension modules (which can now implement mixed-type
1843 numerical operators without having to use coercion), but
1844 occasionally, in boundary cases the coercion semantics have changed
1845 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001846 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001847 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001848 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001849
Guido van Rossumf98eda02001-01-17 15:54:45 +00001850- In connection with the coercion changes, a new built-in singleton
1851 object, NotImplemented is defined. This can be returned for
1852 operations that wish to indicate they are not implemented for a
1853 particular combination of arguments. From C, this is
1854 Py_NotImplemented.
1855
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001856- The interpreter accepts now bytecode files on the command line even
1857 if they do not have a .pyc or .pyo extension. On Linux, after executing
1858
Martin v. Löwise214baa2001-02-04 22:37:56 +00001859import imp,sys,string
1860magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1861reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1862open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001863
1864 any byte code file can be used as an executable (i.e. as an argument
1865 to execve(2)).
1866
Tim Peters9940b802000-12-01 07:59:35 +00001867- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001868 character. In 1.6 and earlier, they never produced a sign,
1869 and raised an error if the value of the long was too large
1870 to fit in a Python int. In 2.0, they produced a sign if and
1871 only if too large to fit in an int. This was inconsistent
1872 across platforms (because the size of an int varies across
1873 platforms), and inconsistent with hex() and oct(). Example:
1874
1875 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001876 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001877 'ffffffbe' # in 2.0 and before, on 32-bit machines
1878 >>> hex(-0x42L)
1879 '-0x42L' # in all versions of Python
1880
Tim Peters9940b802000-12-01 07:59:35 +00001881 The behavior of %d formats for negative Python longs remains
1882 the same as in 2.0 (although in 1.6 and before, they raised
1883 an error if the long didn't fit in a Python int).
1884
1885 %u formats don't make sense for Python longs, but are allowed
1886 and treated the same as %d in 2.1. In 2.0, a negative long
1887 formatted via %u produced a sign if and only if too large to
1888 fit in an int. In 1.6 and earlier, a negative long formatted
1889 via %u raised an error if it was too big to fit in an int.
1890
Guido van Rossum3661d392000-12-12 22:10:31 +00001891- Dictionary objects have an odd new method, popitem(). This removes
1892 an arbitrary item from the dictionary and returns it (in the form of
1893 a (key, value) pair). This can be useful for algorithms that use a
1894 dictionary as a bag of "to do" items and repeatedly need to pick one
1895 item. Such algorithms normally end up running in quadratic time;
1896 using popitem() they can usually be made to run in linear time.
1897
Tim Peters36cdad12000-12-29 02:06:45 +00001898Standard library
1899
Thomas Woutersfe385252001-01-19 23:16:56 +00001900- In the time module, the time argument to the functions strftime,
1901 localtime, gmtime, asctime and ctime is now optional, defaulting to
1902 the current time (in the local timezone).
1903
Guido van Rossumda91f222001-01-15 16:36:08 +00001904- The ftplib module now defaults to passive mode, which is deemed a
1905 more useful default given that clients are often inside firewalls
1906 these days. Note that this could break if ftplib is used to connect
1907 to a *server* that is inside a firewall, from outside; this is
1908 expected to be a very rare situation. To fix that, you can call
1909 ftp.set_pasv(0).
1910
Martin v. Löwis10a27872001-01-13 09:54:41 +00001911- The module site now treats .pth files not only for path configuration,
1912 but also supports extensions to the initialization code: Lines starting
1913 with import are executed.
1914
Guido van Rossumf61f1662001-01-10 20:13:55 +00001915- There's a new module, warnings, which implements a mechanism for
1916 issuing and filtering warnings. There are some new built-in
1917 exceptions that serve as warning categories, and a new command line
1918 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1919 turns warnings into errors). warnings.warn(message[, category])
1920 issues a warning message; this can also be called from C as
1921 PyErr_Warn(category, message).
1922
1923- A new module xreadlines was added. This exports a single factory
1924 function, xreadlines(). The intention is that this code is the
1925 absolutely fastest way to iterate over all lines in an open
1926 file(-like) object:
1927
1928 import xreadlines
1929 for line in xreadlines.xreadlines(file):
1930 ...do something to line...
1931
1932 This is equivalent to the previous the speed record holder using
1933 file.readlines(sizehint). Note that if file is a real file object
1934 (as opposed to a file-like object), this is equivalent:
1935
1936 for line in file.xreadlines():
1937 ...do something to line...
1938
Tim Peters36cdad12000-12-29 02:06:45 +00001939- The bisect module has new functions bisect_left, insort_left,
1940 bisect_right and insort_right. The old names bisect and insort
1941 are now aliases for bisect_right and insort_right. XXX_right
1942 and XXX_left methods differ in what happens when the new element
1943 compares equal to one or more elements already in the list: the
1944 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001945 right. Code that doesn't care where equal elements end up should
1946 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001947
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001948- The new curses.panel module wraps the panel library that forms part
1949 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1950
Guido van Rossumf61f1662001-01-10 20:13:55 +00001951- The SocketServer module now sets the allow_reuse_address flag by
1952 default in the TCPServer class.
1953
1954- A new function, sys._getframe(), returns the stack frame pointer of
1955 the caller. This is intended only as a building block for
1956 higher-level mechanisms such as string interpolation.
1957
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001958- The pyexpat module supports a number of new handlers, which are
1959 available only in expat 1.2. If invocation of a callback fails, it
1960 will report an additional frame in the traceback. Parser objects
1961 participate now in garbage collection. If expat reports an unknown
1962 encoding, pyexpat will try to use a Python codec; that works only
1963 for single-byte charsets. The parser type objects is exposed as
1964 XMLParserObject.
1965
1966- xml.dom now offers standard definitions for symbolic node type and
1967 exception code constants, and a hierarchy of DOM exceptions. minidom
1968 was adjusted to use them.
1969
1970- The conformance of xml.dom.minidom to the DOM specification was
1971 improved. It detects a number of additional error cases; the
1972 previous/next relationship works even when the tree is modified;
1973 Node supports the normalize() method; NamedNodeMap, DocumentType and
1974 DOMImplementation classes were added; Element supports the
1975 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1976 method.
1977
Guido van Rossumf61f1662001-01-10 20:13:55 +00001978Build issues
1979
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001980- For Unix (and Unix-compatible) builds, configuration and building of
1981 extension modules is now greatly automated. Rather than having to
1982 edit the Modules/Setup file to indicate which modules should be
1983 built and where their include files and libraries are, a
1984 distutils-based setup.py script now takes care of building most
1985 extension modules. All extension modules built this way are built
1986 as shared libraries. Only a few modules that must be linked
1987 statically are still listed in the Setup file; you won't need to
1988 edit their configuration.
1989
1990- Python should now build out of the box on Cygwin. If it doesn't,
1991 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001992
1993- Python now always uses its own (renamed) implementation of getopt()
1994 -- there's too much variation among C library getopt()
1995 implementations.
1996
1997- C++ compilers are better supported; the CXX macro is always set to a
1998 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001999
Tim Petersd92dfe02000-12-12 01:18:41 +00002000Windows changes
2001
2002- select module: By default under Windows, a select() call
2003 can specify no more than 64 sockets. Python now boosts
2004 this Microsoft default to 512. If you need even more than
2005 that, see the MS docs (you'll need to #define FD_SETSIZE
2006 and recompile Python from source).
2007
Guido van Rossumf61f1662001-01-10 20:13:55 +00002008- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2009 subdirectory is no more!
2010
Tim Petersa3a3a032000-11-30 05:22:44 +00002011
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002012What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002013=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002014
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002015Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002016changes are in the file HISTORY. If you are making the jump directly
2017from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2018HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002019
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002020Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2021the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2022http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002023
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002024--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002025
2026======================================================================
2027
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002028What's new in 2.0 (since release candidate 1)?
2029==============================================
2030
2031Standard library
2032
2033- The copy_reg module was modified to clarify its intended use: to
2034 register pickle support for extension types, not for classes.
2035 pickle() will raise a TypeError if it is passed a class.
2036
2037- Fixed a bug in gettext's "normalize and expand" code that prevented
2038 it from finding an existing .mo file.
2039
2040- Restored support for HTTP/0.9 servers in httplib.
2041
Tim Peters989b7b92000-10-16 20:24:53 +00002042- The math module was changed to stop raising OverflowError in case of
2043 underflow, and return 0 instead in underflow cases. Whether Python
2044 used to raise OverflowError in case of underflow was platform-
2045 dependent (it did when the platform math library set errno to ERANGE
2046 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002047
2048- Fixed a bug in StringIO that occurred when the file position was not
2049 at the end of the file and write() was called with enough data to
2050 extend past the end of the file.
2051
2052- Fixed a bug that caused Tkinter error messages to get lost on
2053 Windows. The bug was fixed by replacing direct use of
2054 interp->result with Tcl_GetStringResult(interp).
2055
2056- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2057 redirect response.
2058
2059- Several changes were made to distutils: Some debugging code was
2060 removed from util. Fixed the installer used when an external zip
2061 program (like WinZip) is not found; the source code for this
2062 installer is in Misc/distutils. check_lib() was modified to behave
2063 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2064 test for whether installed modules are on sys.path was changed to
2065 use both normcase() and normpath().
2066
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002067- Several minor bugs were fixed in the xml package (the minidom,
2068 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002069
2070- The regression test driver (regrtest.py) behavior when invoked with
2071 -l changed: It now reports a count of objects that are recognized as
2072 garbage but not freed by the garbage collector.
2073
Tim Peters989b7b92000-10-16 20:24:53 +00002074- The regression test for the math module was changed to test
2075 exceptional behavior when the test is run in verbose mode. Python
2076 cannot yet guarantee consistent exception behavior across platforms,
2077 so the exception part of test_math is run only in verbose mode, and
2078 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002079
2080Internals
2081
2082- PyOS_CheckStack() has been disabled on Win64, where it caused
2083 test_sre to fail.
2084
2085Build issues
2086
2087- Changed compiler flags, so that gcc is always invoked with -Wall and
2088 -Wstrict-prototypes. Users compiling Python with GCC should see
2089 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002090 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002091 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002092
Tim Petersa3a3a032000-11-30 05:22:44 +00002093- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002094
2095Tools and other miscellany
2096
2097- The compiler in Tools/compiler was updated to support the new
2098 language features introduced in 2.0: extended print statement, list
2099 comprehensions, and augmented assignments. The new compiler should
2100 also be backwards compatible with Python 1.5.2; the compiler will
2101 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002102 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002103
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002104What's new in 2.0 release candidate 1 (since beta 2)?
2105=====================================================
2106
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002107What is release candidate 1?
2108
2109We believe that release candidate 1 will fix all known bugs that we
2110intend to fix for the 2.0 final release. This release should be a bit
2111more stable than the previous betas. We would like to see even more
2112widespread testing before the final release, so we are producing this
2113release candidate. The final release will be exactly the same unless
2114any show-stopping (or brown bag) bugs are found by testers of the
2115release candidate.
2116
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002117All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002118to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002119
2120Core language, builtins, and interpreter
2121
2122- A bug that caused crashes when __coerce__ was used with augmented
2123 assignment, e.g. +=, was fixed.
2124
2125- Raise ZeroDivisionError when raising zero to a negative number,
2126 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2127 power operator and the result of math.pow(0.0, -2.0) will vary by
2128 platform. On Linux, it raises a ValueError.
2129
2130- A bug in Unicode string interpolation was fixed that occasionally
2131 caused errors with formats including "%%". For example, the
2132 following expression "%% %s" % u"abc" no longer raises a TypeError.
2133
2134- Compilation of deeply nested expressions raises MemoryError instead
2135 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2136
2137- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2138 rendering them useless. They are now written in binary mode again.
2139
2140Standard library
2141
2142- Keyword arguments are now accepted for most pattern and match object
2143 methods in SRE, the standard regular expression engine.
2144
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002145- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002146 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002147
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002148- Several bugs in the Unicode handling and error handling in _tkinter
2149 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002150
2151- Fix memory management errors in Merge() and Tkapp_Call() routines.
2152
2153- Several changes were made to cStringIO to make it compatible with
2154 the file-like object interface and with StringIO. If operations are
2155 performed on a closed object, an exception is raised. The truncate
2156 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002157 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002158
2159- There were many changes made to the linuxaudiodev module and its
2160 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002161 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002162
2163 Note that this module is named poorly, because it should work
2164 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002165 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002166
2167 The module now raises exceptions when errors occur instead of
2168 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2169 audio) and defines a getptr() method that calls the
2170 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2171
2172- The library_version attribute, introduced in an earlier beta, was
2173 removed because it can not be supported with early versions of the C
2174 readline library, which provides no way to determine the version at
2175 compile-time.
2176
2177- The binascii module is now enabled on Win64.
2178
Tim Peters46446d62000-10-09 21:19:31 +00002179- tokenize.py no longer suffers "recursion depth" errors when parsing
2180 programs with very long string literals.
2181
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002182Internals
2183
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002184- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002185 which is called when the interpreter starts up to determine where
2186 the standard library is installed. These vulnerabilities affect all
2187 previous versions of Python and can be exploited by setting very
2188 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2189 setuid Python script, although use of the wrapper in
2190 Misc/setuid-prog.c will eliminate the vulnerability.
2191
2192- Fixed garbage collection bugs in instance creation that were
2193 triggered when errors occurred during initialization. The solution,
2194 applied in cPickle and in PyInstance_New(), is to call
2195 PyObject_GC_Init() after the initialization of the object's
2196 container attributes is complete.
2197
2198- pyexpat adds definitions of PyModule_AddStringConstant and
2199 PyModule_AddObject if the Python version is less than 2.0, which
2200 provides compatibility with PyXML on Python 1.5.2.
2201
2202- If the platform has a bogus definition for LONG_BIT (the number of
2203 bits in a long), an error will be reported at compile time.
2204
2205- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2206 collection crashes and possibly other, unreported crashes.
2207
2208- Fixed a memory leak in _PyUnicode_Fini().
2209
2210Build issues
2211
2212- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002213 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002214 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002215
2216- The mmap.PAGESIZE constant is now initialized using sysconf when
2217 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2218
2219- The md5 file should now compile on all platforms.
2220
2221- The select module now compiles on platforms that do not define
2222 POLLRDNORM and related constants.
2223
2224- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002225 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002226
Jeremy Hylton10921202000-10-09 18:34:12 +00002227- BeOS: A number of changes were made to the build and installation
2228 process. ar-fake now operates on a directory of object files.
2229 dl_export.h is gone, and its macros now appear on the mwcc command
2230 line during build on PPC BeOS.
2231
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002232- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002233 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002234
2235- Cygwin: Support for shared libraries, Tkinter, and sockets.
2236
2237- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2238
2239Tools and other miscellany
2240
2241- Removed debugging prints from main used with freeze.
2242
Tim Peters46446d62000-10-09 21:19:31 +00002243- IDLE auto-indent no longer crashes when it encounters Unicode
2244 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002245
2246What's new in 2.0 beta 2 (since beta 1)?
2247========================================
2248
2249Core language, builtins, and interpreter
2250
Tim Peters482c0212000-09-26 06:33:09 +00002251- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002252 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002253
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002254- Add -h and -V command line options to print the usage message and
2255 Python version number and exit immediately.
2256
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002257- eval() and exec accept Unicode objects as code parameters.
2258
2259- getattr() and setattr() now also accept Unicode objects for the
2260 attribute name, which are converted to strings using the default
2261 encoding before lookup.
2262
2263- Multiplication on string and Unicode now does proper bounds
2264 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2265 string is too long."
2266
2267- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002268 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002269
Jeremy Hylton1b618592000-09-26 05:32:36 +00002270
2271Standard library and extensions
2272
Guido van Rossum5b08f132001-04-16 02:05:23 +00002273- socket module: the OpenSSL code now adds support for RAND_status()
2274 and EGD (Entropy Gathering Device).
2275
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002276- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002277 argument checking; it still takes no arguments.
2278
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002279- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002280
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002281- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002282
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002283- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002284
2285- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002286 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002287
2288- copy: Copy Unicode objects atomically.
2289
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002290- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002291
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002292- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002293
Fred Drake67233bc2000-09-26 16:40:27 +00002294- dbm: Add get() and setdefault() methods to dbm object. Add constant
2295 `library' to module that names the library used. Added doc strings
2296 and method names to error messages. Uses configure to determine
2297 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2298 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002299
2300- distutils: Update to version 0.9.3.
2301
2302- dl: Add several dl.RTLD_ constants.
2303
2304- fpectl: Now supported on FreeBSD.
2305
2306- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2307 found by the collector will be saved in gc.garbage. This is useful
2308 for debugging a program that creates reference cycles.
2309
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002310- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002311 of HTTP class. Do not close socket on zero-length response. Do not
2312 crash when server sends invalid content-length header.
2313
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002314- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002315
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002316- marshal: When reading a short, sign-extend on platforms where shorts
2317 are bigger than 16 bits. When reading a long, repair the unportable
2318 sign extension that was being done for 64-bit machines. (It assumed
2319 that signed right shift sign-extends.)
2320
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002321- operator: Add contains(), invert(), __invert__() as aliases for
2322 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002323
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002324- os: Add support for popen2() and popen3() on all platforms where
2325 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002326
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002327- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002328 clicking on a file in Explorer (or passing the file name to the
2329 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002330
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002331- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002332 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002333
2334- pickle: Now raises ValueError when an invalid pickle that contains
2335 a non-string repr where a string repr was expected. This behavior
2336 matches cPickle.
2337
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002338- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002339
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002340- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002341
2342- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002343 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002344 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002345
2346- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002347 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002348
2349- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002350 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002351 few cycles during startup since the first call to
2352 setdefaultencoding() will initialize the codec registry and the
2353 encodings package.
2354
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002355- socket: Support for size hint in readlines() method of object returned
2356 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002357
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002358- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002359 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002360 is followed by whitespace.
2361
Tim Petersa3a3a032000-11-30 05:22:44 +00002362- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002363
2364- struct: Check ranges for bytes and shorts.
2365
2366- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002367 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002368
2369- Tkinter: Image objects are now guaranteed to have unique ids. Set
2370 event.delta to zero if Tk version doesn't support mousewheel.
2371 Removed some debugging prints.
2372
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002373- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002374
Fred Drake67233bc2000-09-26 16:40:27 +00002375- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002376 which works around a bug in Norton AntiVirus 2000 that leads directly
2377 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002378
2379- xml: New version detection code allows PyXML to override standard
2380 XML package if PyXML version is greater than 0.6.1.
2381
Fred Drake64bb3802000-09-26 16:21:35 +00002382- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2383 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2384 tree only for nodes which are sufficiently interesting to a specific
2385 application. Does not provide the HTML-specific extensions. Still
2386 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002387
Fred Drake64bb3802000-09-26 16:21:35 +00002388- xml.sax: SAX 2 support for Python, including all the handler
2389 interfaces needed to process XML 1.0 compliant XML. Some
2390 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002391
Fred Drake64bb3802000-09-26 16:21:35 +00002392- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2393 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002394
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002395
Jeremy Hylton1b618592000-09-26 05:32:36 +00002396C API
2397
2398- Add three new convenience functions for module initialization --
2399 PyModule_AddObject(), PyModule_AddIntConstant(), and
2400 PyModule_AddStringConstant().
2401
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002402- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002403 removed and add #error to Python.h if NULL isn't defined after
2404 #include of stdio.h.
2405
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002406- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002407 backwards compatibility (at the source level) with old extensions.
2408
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002409- A wrapper API was added for signal() and sigaction(). Instead of
2410 either function, always use PyOS_getsig() to get a signal handler
2411 and PyOS_setsig() to set one. A new convenience typedef
2412 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002413
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002414- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002415 internal data buffer and size of a string object -- or the default
2416 encoded version of a Unicode object.
2417
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002418- PyString_Size() and PyString_AsString() accept Unicode objects.
2419
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002420- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002421 exists). INT_MAX and LONG_MAX will always be defined, even if
2422 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002423
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002424- PyFloat_FromString takes a second argument, pend, that was
2425 effectively useless. It is now officially useless but preserved for
2426 backwards compatibility. If the pend argument is not NULL, *pend is
2427 set to NULL.
2428
2429- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2430 for the attribute name. See note on getattr() above.
2431
2432- A few bug fixes to argument processing for Unicode.
2433 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2434 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2435 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002436 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002437
2438- Py_BuildValue accepts B format (for bgen-generated code).
2439
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002440
Jeremy Hylton1b618592000-09-26 05:32:36 +00002441Internals
2442
2443- On Unix, fix code for finding Python installation directory so that
2444 it works when argv[0] is a relative path.
2445
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002446- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002447 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002448 rather than by generating a copy of the object.
2449
Tim Peters482c0212000-09-26 06:33:09 +00002450- Several of the internal Unicode tables are much smaller now, and
2451 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002452
Jeremy Hylton97693b02000-09-26 17:42:51 +00002453- In the garbage collector: Fixed bug in collection of tuples. Fixed
2454 bug that caused some instances to be removed from the container set
2455 while they were still live. Fixed parsing in gc.set_debug() for
2456 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002457
2458- Fixed refcount problem in instance deallocation that only occurred
2459 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2460
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002461- On Windows, getpythonregpath is now protected against null data in
2462 registry key.
2463
2464- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002465 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002466
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002467
Jeremy Hylton1b618592000-09-26 05:32:36 +00002468Build and platform-specific issues
2469
2470- Better support of GNU Pth via --with-pth configure option.
2471
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002472- Python/C API now properly exposed to dynamically-loaded extension
2473 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002474
2475- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2476 Don't define MS_SYNC to be zero when it is undefined. Added missing
2477 prototypes in posixmodule.c.
2478
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002479- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002480 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002481
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002482- Fix largefile support on older NetBSD systems and OpenBSD by adding
2483 define for TELL64.
2484
2485
2486Tools and other miscellany
2487
2488- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2489
2490- freeze: The modulefinder now works with 2.0 opcodes.
2491
Tim Petersa3a3a032000-11-30 05:22:44 +00002492- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002493 Move hackery of sys.argv until after the Tk instance has been
2494 created, which allows the application-specific Tkinter
2495 initialization to be executed if present; also pass an explicit
2496 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002497
Jeremy Hylton1b618592000-09-26 05:32:36 +00002498
2499What's new in 2.0 beta 1?
2500=========================
2501
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002502Source Incompatibilities
2503------------------------
2504
2505None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2506such as single-argument append(), connect() and bind(), and changes to
2507str(long) and repr(float).
2508
2509
2510Binary Incompatibilities
2511------------------------
2512
2513- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2514with Python 2.0; these extensions will have to be rebuilt for Python
25152.0.
2516
2517- On Windows, attempting to import a third party extension built for
2518Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2519can do about this. Check your PYTHONPATH environment variable!
2520
2521- Python bytecode files (*.pyc and *.pyo) are not compatible between
2522releases.
2523
2524
2525Overview of Changes Since 1.6
2526-----------------------------
2527
2528There are many new modules (including brand new XML support through
2529the xml package, and i18n support through the gettext module); a list
2530of all new modules is included below. Lots of bugs have been fixed.
2531
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002532The process for making major new changes to the language has changed
2533since Python 1.6. Enhancements must now be documented by a Python
2534Enhancement Proposal (PEP) before they can be accepted.
2535
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002536There are several important syntax enhancements, described in more
2537detail below:
2538
2539 - Augmented assignment, e.g. x += 1
2540
2541 - List comprehensions, e.g. [x**2 for x in range(10)]
2542
2543 - Extended import statement, e.g. import Module as Name
2544
2545 - Extended print statement, e.g. print >> file, "Hello"
2546
2547Other important changes:
2548
2549 - Optional collection of cyclical garbage
2550
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002551Python Enhancement Proposal (PEP)
2552---------------------------------
2553
2554PEP stands for Python Enhancement Proposal. A PEP is a design
2555document providing information to the Python community, or describing
2556a new feature for Python. The PEP should provide a concise technical
2557specification of the feature and a rationale for the feature.
2558
2559We intend PEPs to be the primary mechanisms for proposing new
2560features, for collecting community input on an issue, and for
2561documenting the design decisions that have gone into Python. The PEP
2562author is responsible for building consensus within the community and
2563documenting dissenting opinions.
2564
2565The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002566
2567Augmented Assignment
2568--------------------
2569
2570This must have been the most-requested feature of the past years!
2571Eleven new assignment operators were added:
2572
Guido van Rossume905e952000-09-05 12:42:46 +00002573 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002574
2575For example,
2576
2577 A += B
2578
2579is similar to
2580
2581 A = A + B
2582
2583except that A is evaluated only once (relevant when A is something
2584like dict[index].attr).
2585
2586However, if A is a mutable object, A may be modified in place. Thus,
2587if A is a number or a string, A += B has the same effect as A = A+B
2588(except A is only evaluated once); but if a is a list, A += B has the
2589same effect as A.extend(B)!
2590
2591Classes and built-in object types can override the new operators in
2592order to implement the in-place behavior; the not-in-place behavior is
2593used automatically as a fallback when an object doesn't implement the
2594in-place behavior. For classes, the method name is derived from the
2595method name for the corresponding not-in-place operator by inserting
2596an 'i' in front of the name, e.g. __iadd__ implements in-place
2597__add__.
2598
2599Augmented assignment was implemented by Thomas Wouters.
2600
2601
2602List Comprehensions
2603-------------------
2604
2605This is a flexible new notation for lists whose elements are computed
2606from another list (or lists). The simplest form is:
2607
2608 [<expression> for <variable> in <sequence>]
2609
Guido van Rossum56db0952000-09-06 23:34:25 +00002610For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002611This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002612
2613You can also add a condition:
2614
2615 [<expression> for <variable> in <sequence> if <condition>]
2616
2617For example, [w for w in words if w == w.lower()] would yield the list
2618of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002619than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002620
2621You can also have nested for loops and more than one 'if' clause. For
2622example, here's a function that flattens a sequence of sequences::
2623
2624 def flatten(seq):
2625 return [x for subseq in seq for x in subseq]
2626
2627 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2628
2629This prints
2630
2631 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2632
2633List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002634Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002635
2636
2637Extended Import Statement
2638-------------------------
2639
2640Many people have asked for a way to import a module under a different
2641name. This can be accomplished like this:
2642
2643 import foo
2644 bar = foo
2645 del foo
2646
2647but this common idiom gets old quickly. A simple extension of the
2648import statement now allows this to be written as follows:
2649
2650 import foo as bar
2651
2652There's also a variant for 'from ... import':
2653
2654 from foo import bar as spam
2655
2656This also works with packages; e.g. you can write this:
2657
2658 import test.regrtest as regrtest
2659
2660Note that 'as' is not a new keyword -- it is recognized only in this
2661context (this is only possible because the syntax for the import
2662statement doesn't involve expressions).
2663
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002664Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002665
2666
2667Extended Print Statement
2668------------------------
2669
2670Easily the most controversial new feature, this extension to the print
2671statement adds an option to make the output go to a different file
2672than the default sys.stdout.
2673
2674For example, to write an error message to sys.stderr, you can now
2675write:
2676
2677 print >> sys.stderr, "Error: bad dog!"
2678
2679As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002680evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002681
2682 print >> None, "Hello world"
2683
2684is equivalent to
2685
2686 print "Hello world"
2687
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002688Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002689
2690
2691Optional Collection of Cyclical Garbage
2692---------------------------------------
2693
2694Python is now equipped with a garbage collector that can hunt down
2695cyclical references between Python objects. It's no replacement for
2696reference counting; in fact, it depends on the reference counts being
2697correct, and decides that a set of objects belong to a cycle if all
2698their reference counts can be accounted for from their references to
2699each other. This devious scheme was first proposed by Eric Tiedemann,
2700and brought to implementation by Neil Schemenauer.
2701
2702There's a module "gc" that lets you control some parameters of the
2703garbage collection. There's also an option to the configure script
2704that lets you enable or disable the garbage collection. In 2.0b1,
2705it's on by default, so that we (hopefully) can collect decent user
2706experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002707performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002708off by default in the final 2.0 release.
2709
2710
2711Smaller Changes
2712---------------
2713
2714A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2715map(None, seq1, seq2, ...) when the sequences have the same length;
2716i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2717the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002718zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002719
2720sys.version_info is a tuple (major, minor, micro, level, serial).
2721
2722Dictionaries have an odd new method, setdefault(key, default).
2723dict.setdefault(key, default) returns dict[key] if it exists; if not,
2724it sets dict[key] to default and returns that value. Thus:
2725
2726 dict.setdefault(key, []).append(item)
2727
2728does the same work as this common idiom:
2729
2730 if not dict.has_key(key):
2731 dict[key] = []
2732 dict[key].append(item)
2733
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002734There are two new variants of SyntaxError that are raised for
2735indentation-related errors: IndentationError and TabError.
2736
2737Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2738escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002739
2740The limits on the size of expressions and file in Python source code
2741have been raised from 2**16 to 2**32. Previous versions of Python
2742were limited because the maximum argument size the Python VM accepted
2743was 2**16. This limited the size of object constructor expressions,
2744e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2745limit was raised thanks to a patch by Charles Waldman that effectively
2746fixes the problem. It is now much more likely that you will be
2747limited by available memory than by an arbitrary limit in Python.
2748
2749The interpreter's maximum recursion depth can be modified by Python
2750programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2751limit is the maximum number of recursive calls that can be made by
2752Python code. The limit exists to prevent infinite recursion from
2753overflowing the C stack and causing a core dump. The default value is
27541000. The maximum safe value for a particular platform can be found
2755by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002756
2757New Modules and Packages
2758------------------------
2759
2760atexit - for registering functions to be called when Python exits.
2761
2762imputil - Greg Stein's alternative API for writing custom import
2763hooks.
2764
2765pyexpat - an interface to the Expat XML parser, contributed by Paul
2766Prescod.
2767
2768xml - a new package with XML support code organized (so far) in three
2769subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2770would fill a volume. There's a special feature whereby a
2771user-installed package named _xmlplus overrides the standard
2772xmlpackage; this is intended to give the XML SIG a hook to distribute
2773backwards-compatible updates to the standard xml package.
2774
2775webbrowser - a platform-independent API to launch a web browser.
2776
2777
Guido van Rossume905e952000-09-05 12:42:46 +00002778Changed Modules
2779---------------
2780
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002781array -- new methods for array objects: count, extend, index, pop, and
2782remove
2783
2784binascii -- new functions b2a_hex and a2b_hex that convert between
2785binary data and its hex representation
2786
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002787calendar -- Many new functions that support features including control
2788over which day of the week is the first day, returning strings instead
2789of printing them. Also new symbolic constants for days of week,
2790e.g. MONDAY, ..., SUNDAY.
2791
2792cgi -- FieldStorage objects have a getvalue method that works like a
2793dictionary's get method and returns the value attribute of the object.
2794
2795ConfigParser -- The parser object has new methods has_option,
2796remove_section, remove_option, set, and write. They allow the module
2797to be used for writing config files as well as reading them.
2798
2799ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002800optionally support the RFC 959 REST command.
2801
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002802gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002803
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002804httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2805the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002806
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002807locale -- implement getdefaultlocale for Win32 and Macintosh
2808
2809marshal -- no longer dumps core when marshaling deeply nested or
2810recursive data structures
2811
2812os -- new functions isatty, seteuid, setegid, setreuid, setregid
2813
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002814os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2815support under Unix.
2816
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002817os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002818
2819os.path -- fix semantics of os.path.commonprefix
2820
2821smtplib -- support for sending very long messages
2822
2823socket -- new function getfqdn()
2824
2825readline -- new functions to read, write and truncate history files.
2826The readline section of the library reference manual contains an
2827example.
2828
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002829select -- add interface to poll system call
2830
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002831shutil -- new copyfileobj function
2832
2833SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2834HTTP server.
2835
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002836Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002837
2838urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002839e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002840
2841whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002842
2843
2844Obsolete Modules
2845----------------
2846
2847None. However note that 1.6 made a whole slew of modules obsolete:
2848stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2849poly, zmod, strop, util, whatsound.
2850
2851
2852Changed, New, Obsolete Tools
2853----------------------------
2854
Tim Peters8b092332000-09-05 20:15:25 +00002855None.
Guido van Rossume905e952000-09-05 12:42:46 +00002856
2857
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002858C-level Changes
2859---------------
2860
2861Several cleanup jobs were carried out throughout the source code.
2862
2863All C code was converted to ANSI C; we got rid of all uses of the
2864Py_PROTO() macro, which makes the header files a lot more readable.
2865
2866Most of the portability hacks were moved to a new header file,
2867pyport.h; several other new header files were added and some old
2868header files were removed, in an attempt to create a more rational set
2869of header files. (Few of these ever need to be included explicitly;
2870they are all included by Python.h.)
2871
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002872Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002873and Win64, especially for the new Intel Itanium processor. Mick also
2874added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002875
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002876The C APIs to return an object's size have been update to consistently
2877use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2878previous versions, the abstract interfaces used PyXXX_Length and the
2879concrete interfaces used PyXXX_Size. The old names,
2880e.g. PyObject_Length, are still available for backwards compatibility
2881at the API level, but are deprecated.
2882
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002883The PyOS_CheckStack function has been implemented on Windows by
2884Fredrik Lundh. It prevents Python from failing with a stack overflow
2885on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002886
2887The GC changes resulted in creation of two new slots on object,
2888tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002889the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002890
2891The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002892C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002893
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002894PyErr_Format has been updated to automatically calculate the size of
2895the buffer needed to hold the formatted result string. This change
2896prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002897
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002898New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002899
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002900PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2901that are the same as their non-Ex counterparts except they take an
2902extra flag argument that tells them to close the file when done.
2903
2904XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002905
Tim Peters8b092332000-09-05 20:15:25 +00002906
2907Windows Changes
2908---------------
2909
2910New popen2/popen3/peopen4 in os module (see Changed Modules above).
2911
2912os.popen is much more usable on Windows 95 and 98. See Microsoft
2913Knowledge Base article Q150956. The Win9x workaround described there
2914is implemented by the new w9xpopen.exe helper in the root of your
2915Python installation. Note that Python uses this internally; it is not
2916a standalone program.
2917
2918Administrator privileges are no longer required to install Python
2919on Windows NT or Windows 2000. If you have administrator privileges,
2920Python's registry info will be written under HKEY_LOCAL_MACHINE.
2921Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002922under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002923uses of Python, but will prevent some advanced uses from working
2924(for example, running a Python script as an NT service, or possibly
2925from CGI).
2926
2927[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2928installer; instead, it installs the needed Tcl/Tk files directly in the
2929Python directory. If you already have a Tcl/Tk installation, this
2930wastes some disk space (about 4 Megs) but avoids problems with
2931conflicting Tcl/Tk installations, and makes it much easier for Python
2932to ensure that Tcl/Tk can find all its files.
2933
2934[This was new in 1.6] The Windows installer now installs by default in
2935\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2936
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002937
2938Updates to the changes between 1.5.2 and 1.6
2939--------------------------------------------
2940
2941The 1.6 NEWS file can't be changed after the release is done, so here
2942is some late-breaking news:
2943
2944New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2945and changes to getlocale() and setlocale().
2946
2947The new module is now enabled per default.
2948
2949It is not true that the encodings codecs cannot be used for normal
2950strings: the string.encode() (which is also present on 8-bit strings
2951!) allows using them for 8-bit strings too, e.g. to convert files from
2952cp1252 (Windows) to latin-1 or vice-versa.
2953
2954Japanese codecs are available from Tamito KAJIYAMA:
2955http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2956
2957
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002958======================================================================