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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
Tim Peters76f7fe32001-11-15 20:02:21 +00007- Restrictions on multiple inheritance from classes with different
8 metatypes have been relaxed. The only builtin metatypes are one for
9 classic classes a second for new-style classes, so the primary
10 visible effect is that this works now:
11
12 class Classic: pass
13 class Mixed(Classic, object): now
14
15 The MRO (method resolution order) for each base class is respected
16 according to its kind, but the MRO for the derived class is computed
17 using new-style MRO rules if any base clase is a new-style class.
18 This needs to be documented.
19
Tim Petersa427a2b2001-10-29 22:25:45 +000020- The new builtin dictionary() constructor, and dictionary type, have
21 been renamed to dict. This reflects a decade of common usage.
22
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000023- New-style classes can now have a __del__ method, which is called
24 when the instance is deleted (just like for classic classes).
25
Guido van Rossum12d955c2001-10-26 14:56:06 +000026- Assignment to object.__dict__ is now possible, for objects that are
27 instances of new-style classes that have a __dict__ (unless the base
28 class forbids it).
29
Tim Peters1fc240e2001-10-26 05:06:50 +000030- dictionary() now accepts an iterable object producing 2-sequences.
31 For example, dictionary(d.items()) == d for any dictionary d. The
32 argument, and the elements of the argument, can be any iterable
33 objects.
34
Guido van Rossumc8e56452001-10-22 00:43:43 +000035- Methods of built-in types now properly check for keyword arguments
36 (formerly these were silently ignored). The only built-in methods
37 that take keyword arguments are __call__, __init__ and __new__.
38
Guido van Rossum86443212001-10-27 22:28:54 +000039- The socket function has been converted to a type; see below.
40
Tim Peters84362bc2001-10-19 17:55:30 +000041Core and builtins
42
Jeremy Hylton249aaed2001-11-09 21:06:24 +000043- Assignment to __debug__ raises SyntaxError at compile-time. This
44 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
45 (below) says.
46
Guido van Rossum12d955c2001-10-26 14:56:06 +000047- Clarified the error messages for unsupported operands to an operator
48 (like 1 + '').
49
Tim Peters84362bc2001-10-19 17:55:30 +000050Extension modules
51
Tim Peters5ebfd362001-11-13 23:11:19 +000052- mmap has a new keyword argument, "access", allowing a uniform way for
53 both Windows and Unix users to create read-only, write-through and
54 copy-on-write memory mappings. This was previously possible only on
55 Unix. A new keyword argument was required to support this in a
56 uniform way because the mmap() signuatures had diverged across
57 platforms. Thanks to Jay T Miller for repairing this!
58
Tim Peters169ded02001-11-03 19:57:21 +000059- By default, the gc.garbage list now contains only those instances in
60 unreachable cycles that have __del__ methods; in 2.1 it contained all
61 instances in unreachable cycles. "Instances" here has been generalized
62 to include instances of both new-style and old-style classes.
63
Guido van Rossum12d955c2001-10-26 14:56:06 +000064- The socket module defines a new method for socket objects,
65 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000066 send() until all data has been sent. Also, the socket function has
67 been converted to a subclassable type, like list and tuple (etc.)
68 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000069
70- Various bugfixes to the curses module. There is now a test suite
71 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +000072
Guido van Rossum692adf12001-10-30 03:03:03 +000073- binascii.b2a_base64 no longer places an arbitrary restriction of 57
74 bytes on its input.
75
Tim Peters84362bc2001-10-19 17:55:30 +000076Library
77
Tim Peters5ebfd362001-11-13 23:11:19 +000078- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +000079 convenience function.
80
Tim Peters75335872001-11-03 19:35:43 +000081- Symbolic group names in regular expressions must be unique. For
82 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
83 single name can't mean both "group 1" and "group 2" simultaneously.
84 Python 2.2 detects this error at regexp compilation time; previously,
85 the error went undetected, and results were unpredictable.
86
Martin v. Löwisb7b32602001-11-02 23:48:20 +000087- Tix exposes more commands through the classes DirSelectBox,
88 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
89 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
90 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
91
Tim Peters98791af2001-10-23 01:59:54 +000092- Traceback objects are now scanned by cyclic garbage collection, so
93 cycles created by casual use of sys.exc_info() no longer cause
94 permanent memory leaks (provided garbage collection is enabled).
95
Guido van Rossum49192142001-10-24 20:51:44 +000096- os.extsep -- a new variable needed by the RISCOS support. It is the
97 separator used by extensions, and is '.' on all platforms except
98 RISCOS, where it is '/'. There is no need to use this variable
99 unless you have a masochistic desire to port your code to RISCOS.
100
Tim Peters84362bc2001-10-19 17:55:30 +0000101Tools/Demos
102
103Build
104
105C API
106
Tim Peters1fc240e2001-10-26 05:06:50 +0000107- New function PySequence_Fast_GET_SIZE() returns the size of a non-
108 NULL result from PySequence_Fast(), more quickly than calling
109 PySequence_Size().
110
Tim Peters84362bc2001-10-19 17:55:30 +0000111New platforms
112
Guido van Rossum86443212001-10-27 22:28:54 +0000113- We've finally confirmed that this release builds on HP-UX 11.00,
114 *with* threads, and passes the test suite.
115
Tim Peters7a33d8b2001-11-05 02:51:07 +0000116- Thanks to a series of patches from Michael Muller, Python may build
117 again under OS/2 Visual Age C++.
118
Guido van Rossum49192142001-10-24 20:51:44 +0000119- Updated RISCOS port by Dietmar Schwertberger.
120
Tim Peters84362bc2001-10-19 17:55:30 +0000121Tests
122
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000123- Added a test script for the curses module. It isn't run automatically;
124 regrtest.py must be run with '-u curses' to enable it.
125
Tim Peters84362bc2001-10-19 17:55:30 +0000126Windows
127
128
Tim Petersabf925f2001-09-28 21:53:42 +0000129What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000130Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000131===========================
132
133Type/class unification and new-style classes
134
Guido van Rossum687ae002001-10-15 22:03:32 +0000135- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000136 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000137 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000138 remains: the __dict__ of a new-style class is a read-only proxy; you
139 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000140 __defined__ attribute of new-style types no longer exists, for lack
141 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000142 future a __cache__ may be resurrected with a similar function, if I
143 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000144
Tim Peters1c9ca872001-10-04 06:43:12 +0000145- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
146 always returned None, even when there was a class docstring).
147
148- doctest now finds and runs docstrings attached to new-style classes,
149 class methods, static methods, and properties.
150
Guido van Rossum9074ef62001-10-16 21:34:49 +0000151Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000152
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000153- A very subtle syntactical pitfall in list comprehensions was fixed.
154 For example: [a+b for a in 'abc', for b in 'def']. The comma in
155 this example is a mistake. Previously, this would silently let 'a'
156 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
157 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
158 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
159 Note that [a for a in <singleton>] is a convoluted way to say
160 [<singleton>] anyway, so it's not like any expressiveness is lost.
161
Guido van Rossum9074ef62001-10-16 21:34:49 +0000162- getattr(obj, name, default) now only catches AttributeError, as
163 documented, rather than returning the default value for all
164 exceptions (which could mask bugs in a __getattr__ hook, for
165 example).
166
Fred Drakecb7a6b52001-10-22 18:41:51 +0000167- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000168 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000169 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000170 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000171
Guido van Rossum1c486092001-10-19 02:05:35 +0000172- unicode(obj) now behaves more like str(obj), accepting arbitrary
173 objects, and calling a __unicode__ method if it exists.
174 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000175 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000176
Barry Warsawf6fb1712001-10-19 05:35:40 +0000177- isinstance() now allows any object as the first argument and a
178 class, a type or something with a __bases__ tuple attribute for the
179 second argument. The second argument may also be a tuple of a
180 class, type, or something with __bases__, in which case isinstance()
181 will return true if the first argument is an instance of any of the
182 things contained in the second argument tuple. E.g.
183
184 isinstance(x, (A, B))
185
186 returns true if x is an instance of A or B.
187
Guido van Rossum9074ef62001-10-16 21:34:49 +0000188Extension modules
189
190- thread.start_new_thread() now returns the thread ID (previously None).
191
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000192- binascii has now two quopri support functions, a2b_qp and b2a_qp.
193
Guido van Rossumc524d952001-10-19 01:31:59 +0000194- readline now supports setting the startup_hook and the
195 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000196
Guido van Rossumc524d952001-10-19 01:31:59 +0000197- os and posix supports chroot(), setgroups() and unsetenv() where
198 available. The stat(), fstat(), statvfs() and fstatvfs() functions
199 now return "pseudo-sequences" -- the various fields can now be
200 accessed as attributes (e.g. os.stat("/").st_mtime) but for
201 backwards compatibility they also behave as a fixed-length sequence.
202 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000203 attributes.
204
205- time: localtime(), gmtime() and strptime() now return a
206 pseudo-sequence similar to the os.stat() return value, with
207 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000208
Guido van Rossum9074ef62001-10-16 21:34:49 +0000209- Decompression objects in the zlib module now accept an optional
210 second parameter to decompress() that specifies the maximum amount
211 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000212
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000213- optional SSL support in the socket module now exports OpenSSL
214 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
215 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000216 automatically seed its PRNG. Also, the keyfile and certfile
217 arguments to socket.ssl() are now optional.
218
219- posixmodule (and by extension, the os module on POSIX platforms) now
220 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000221
Guido van Rossum9074ef62001-10-16 21:34:49 +0000222Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000223
Tim Peters7402f792001-10-02 03:53:41 +0000224- doctest now excludes functions and classes not defined by the module
225 being tested, thanks to Tim Hochberg.
226
Fred Drakecb7a6b52001-10-22 18:41:51 +0000227- HotShot, a new profiler implemented using a C-based callback, has
228 been added. This substantially reduces the overhead of profiling,
229 but it is still quite preliminary. Support modules and
230 documentation will be added in upcoming releases (before 2.2 final).
231
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000232- profile now produces correct output in situations where an exception
233 raised in Python is cleared by C code (e.g. hasattr()). This used
234 to cause wrong output, including spurious claims of recursive
235 functions and attribution of time spent to the wrong function.
236
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000237 The code and documentation for the derived OldProfile and HotProfile
238 profiling classes was removed. The code hasn't worked for years (if
239 you tried to use them, they raised exceptions). OldProfile
240 intended to reproduce the behavior of the profiler Python used more
241 than 7 years ago, and isn't interesting anymore. HotProfile intended
242 to provide a faster profiler (but producing less information), and
243 that's a worthy goal we intend to meet via a different approach (but
244 without losing information).
245
Tim Peterscce092d2001-10-09 05:31:56 +0000246- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000247 a much better system-specific calibration constant. The constant can
248 now be specified in an instance constructor, or as a Profile class or
249 instance variable, instead of by editing profile.py's source code.
250 Calibration must still be done manually (see the docs for the profile
251 module).
252
253 Note that Profile.calibrate() must be overriden by subclasses.
254 Improving the accuracy required exploiting detailed knowledge of
255 profiler internals; the earlier method abstracted away the details
256 and measured a simplified model instead, but consequently computed
257 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000258
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000259- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000260 which indicates whether output is intended for the header 'Q'
261 encoding.
262
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000263- The SocketServer.ThreadingMixIn class now closes the request after
264 finish_request() returns. (Not when it errors out though.)
265
Barry Warsawf6fb1712001-10-19 05:35:40 +0000266- The nntplib module's NNTP.body() method has grown a `file' argument
267 to allow saving the message body to a file.
268
269- The email package has added a class email.Parser.HeaderParser which
270 only parses headers and does not recurse into the message's body.
271 Also, the module/class MIMEAudio has been added for representing
272 audio data (contributed by Anthony Baxter).
273
274- ftplib should be able to handle files > 2GB.
275
276- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
277 ON, and OFF.
278
Fred Drakecb7a6b52001-10-22 18:41:51 +0000279- xml.dom.minidom NodeList objects now support the length attribute
280 and item() method as required by the DOM specifications.
281
Guido van Rossumed554f62001-10-02 23:15:37 +0000282Tools/Demos
283
284- Demo/dns was removed. It no longer serves any purpose; a package
285 derived from it is now maintained by Anthony Baxter, see
286 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000287
Barry Warsawf6fb1712001-10-19 05:35:40 +0000288- The freeze tool has been made more robust, and two new options have
289 been added: -X and -E.
290
Tim Petersabf925f2001-09-28 21:53:42 +0000291Build
292
Barry Warsawf6fb1712001-10-19 05:35:40 +0000293- configure will use CXX in LINKCC if CXX is used to build main() and
294 the system requires to link a C++ main using the C++ compiler.
295
Tim Petersabf925f2001-09-28 21:53:42 +0000296C API
297
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000298- The documentation for the tp_compare slot is updated to require that
299 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
300 not correct. This is not yet enforced but will be enforced in
301 Python 2.3; even later, we may use -2 to indicate errors and +2 for
302 "NotImplemented". Right now, -1 should be used for an error return.
303
Tim Petersd38b1c72001-09-30 05:09:37 +0000304- PyLong_AsLongLong() now accepts int (as well as long) arguments.
305 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
306 as long) arguments.
307
Guido van Rossum3c288632001-10-16 21:13:49 +0000308- PyThread_start_new_thread() now returns a long int giving the thread
309 ID, if one can be calculated; it returns -1 for error, 0 if no
310 thread ID is calculated (this is an incompatible change, but only
311 the thread module used this API). This code has only really been
312 tested on Linux and Windows; other platforms please beware (and
313 report any bugs or strange behavior).
314
Guido van Rossum1c486092001-10-19 02:05:35 +0000315- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
316 input.
317
Tim Petersabf925f2001-09-28 21:53:42 +0000318New platforms
319
320Tests
321
322Windows
323
Tim Peters04cf1d32001-10-09 22:39:40 +0000324- Installer: If you install IDLE, and don't disable file-extension
325 registration, a new "Edit with IDLE" context (right-click) menu entry
326 is created for .py and .pyw files.
327
Tim Peters1ce3cf72001-10-01 17:58:40 +0000328- The signal module now supports SIGBREAK on Windows, thanks to Steven
329 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
330 action remains to call Win32 ExitProcess(). This can be changed via
331 signal.signal(). For example:
332
333 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
334 # (SIGINT) behavior.
335 import signal
336 signal.signal(signal.SIGBREAK,
337 signal.default_int_handler)
338
339 try:
340 while 1:
341 pass
342 except KeyboardInterrupt:
343 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
344 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
345 # program without the possibility for any Python-level cleanup).
346 print "Clean exit"
347
Tim Petersabf925f2001-09-28 21:53:42 +0000348
Tim Petersb07352e2001-09-08 01:25:47 +0000349What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000350Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000351===========================
352
Guido van Rossum808eea72001-09-25 04:15:41 +0000353Type/class unification and new-style classes
354
355- pydoc and inspect are now aware of new-style classes;
356 e.g. help(list) at the interactive prompt now shows proper
357 documentation for all operations on list objects.
358
359- Applications using Jim Fulton's ExtensionClass module can now safely
360 be used with Python 2.2. In particular, Zope 2.4.1 now works with
361 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
362 examples also work again. It is hoped that Gtk and Boost also work
363 with 2.2a4 and beyond. (If you can confirm this, please write
364 webmaster@python.org; if there are still problems, please open a bug
365 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000366
Tim Peters66c1a522001-09-24 21:17:50 +0000367- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
368 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
369 in the constructed property object. fget, fset and fdel weren't
370 discoverable from Python in 2.2a3. __doc__ is new, and allows to
371 associate a docstring with a property.
372
Guido van Rossum808eea72001-09-25 04:15:41 +0000373- Comparison overloading is now more completely implemented. For
374 example, a str subclass instance can properly be compared to a str
375 instance, and it can properly overload comparison. Ditto for most
376 other built-in object types.
377
378- The repr() of new-style classes has changed; instead of <type
379 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
380 *except* for built-in types, which are still rendered as <type
381 'Foo'> (to avoid upsetting existing code that might parse or
382 otherwise rely on repr() of certain type objects).
383
384- The repr() of new-style objects is now always <Foo object at XXX>;
385 previously, it was sometimes <Foo instance at XXX>.
386
387- For new-style classes, what was previously called __getattr__ is now
388 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000389 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000390 one in classic classes is defined which is called only if regular
391 attribute access raises AttributeError; to catch *all* attribute
392 access, you can use __getattribute__ (for new-style classes). If
393 both are defined, __getattribute__ is called first, and if it raises
394 AttributeError, __getattr__ is called.
395
396- The __class__ attribute of new-style objects can be assigned to.
397 The new class must have the same C-level object layout as the old
398 class.
399
400- The builtin file type can be subclassed now. In the usual pattern,
401 "file" is the name of the builtin type, and file() is a new builtin
402 constructor, with the same signature as the builtin open() function.
403 file() is now the preferred way to open a file.
404
405- Previously, __new__ would only see sequential arguments passed to
406 the type in a constructor call; __init__ would see both sequential
407 and keyword arguments. This made no sense whatsoever any more, so
408 now both __new__ and __init__ see all arguments.
409
410- Previously, hash() applied to an instance of a subclass of str or
411 unicode always returned 0. This has been repaired.
412
413- Previously, an operation on an instance of a subclass of an
414 immutable type (int, long, float, complex, tuple, str, unicode),
415 where the subtype didn't override the operation (and so the
416 operation was handled by the builtin type), could return that
417 instance instead a value of the base type. For example, if s was of
418 a str sublass type, s[:] returned s as-is. Now it returns a str
419 with the same value as s.
420
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000421- Provisional support for pickling new-style objects has been added.
422
Guido van Rossum808eea72001-09-25 04:15:41 +0000423Core
424
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000425- file.writelines() now accepts any iterable object producing strings.
426
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000427- PyUnicode_FromEncodedObject() now works very much like
428 PyObject_Str(obj) in that it tries to use __str__/tp_str
429 on the object if the object is not a string or buffer. This
430 makes unicode() behave like str() when applied to non-string/buffer
431 objects.
432
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000433- PyFile_WriteObject now passes Unicode objects to the file's write
434 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000435 of a print statement must support Unicode objects, i.e. they must
436 at least convert them into ASCII strings.
437
Guido van Rossum624c8af2001-09-18 15:21:04 +0000438- Thread scheduling on Solaris should be improved; it is no longer
439 necessary to insert a small sleep at the start of a thread in order
440 to let other runnable threads be scheduled.
441
Tim Petersb07352e2001-09-08 01:25:47 +0000442Library
443
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000444- StringIO.StringIO instances and cStringIO.StringIO instances support
445 read character buffer compatible objects for their .write() methods.
446 These objects are converted to strings and then handled as such
447 by the instances.
448
Barry Warsaw2f600732001-09-24 04:28:10 +0000449- The "email" package has been added. This is basically a port of the
450 mimelib package <http://sf.net/projects/mimelib> with API changes
451 and some implementations updated to use iterators and generators.
452
Tim Peters8a9c2842001-09-22 21:30:22 +0000453- difflib.ndiff() and difflib.Differ.compare() are generators now. This
454 restores the ability of Tools/scripts/ndiff.py to start producing output
455 before the entire comparison is complete.
456
Barry Warsaw58b072d2001-09-22 04:44:21 +0000457- StringIO.StringIO instances and cStringIO.StringIO instances support
458 iteration just like file objects (i.e. their .readline() method is
459 called for each iteration until it returns an empty string).
460
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000461- The codecs module has grown four new helper APIs to access
462 builtin codecs: getencoder(), getdecoder(), getreader(),
463 getwriter().
464
Guido van Rossum624c8af2001-09-18 15:21:04 +0000465- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
466 simplifies writing XML RPC servers.
467
Barry Warsaw647d5e82001-09-28 17:01:02 +0000468- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000469 after interpretation of symbolic links. On non-Unix systems, this
470 is an alias for os.path.abspath().
471
Tim Peters16a77ad2001-09-08 04:00:12 +0000472- operator.indexOf() (PySequence_Index() in the C API) now works with any
473 iterable object.
474
Guido van Rossum624c8af2001-09-18 15:21:04 +0000475- smtplib now supports various authentication and security features of
476 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000477
Guido van Rossum624c8af2001-09-18 15:21:04 +0000478- hmac: a new module implementing keyed hashing for message
479 authentication.
480
481- mimetypes now recognizes more extensions and file types. At the
482 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000483
Guido van Rossum624c8af2001-09-18 15:21:04 +0000484- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000485 Python 2.2 bytecode generation. It has also been promoted from a
486 Tool to a standard library package. (Tools/compiler still exists as
487 a sample driver.)
488
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000489Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000490
Tim Petersb07352e2001-09-08 01:25:47 +0000491Build
492
Guido van Rossum624c8af2001-09-18 15:21:04 +0000493- Large file support (LFS) is now automatic when the platform supports
494 it; no more manual configuration tweaks are needed. On Linux, at
495 least, it's possible to have a system whose C library supports large
496 files but whose kernel doesn't; in this case, large file support is
497 still enabled but doesn't do you any good unless you upgrade your
498 kernel or share your Python executable with another system whose
499 kernel has large file support.
500
501- The configure script now supplies plausible defaults in a
502 cross-compilation environment. This doesn't mean that the supplied
503 values are always correct, or that cross-compilation now works
504 flawlessly -- but it's a first step (and it shuts up most of
505 autoconf's warnings about AC_TRY_RUN).
506
507- The Unix build is now a bit less chatty, courtesy of the parser
508 generator. The build is completely silent (except for errors) when
509 using "make -s", thanks to a -q option to setup.py.
510
Tim Petersb07352e2001-09-08 01:25:47 +0000511C API
512
Guido van Rossum624c8af2001-09-18 15:21:04 +0000513- The "structmember" API now supports some new flag bits to deny read
514 and/or write access to attributes in restricted execution mode.
515
Tim Petersb07352e2001-09-08 01:25:47 +0000516New platforms
517
Guido van Rossum624c8af2001-09-18 15:21:04 +0000518- Compaq's iPAQ handheld, running the "familiar" Linux distribution
519 (http://familiar.handhelds.org).
520
Tim Petersb07352e2001-09-08 01:25:47 +0000521Tests
522
Tim Peters8a9c2842001-09-22 21:30:22 +0000523- The "classic" standard tests, which work by comparing stdout to
524 an expected-output file under Lib/test/output/, no longer stop at
525 the first mismatch. Instead the test is run to completion, and a
526 variant of ndiff-style comparison is used to report all differences.
527 This is much easier to understand than the previous style of reporting.
528
529- The unittest-based standard tests now use regrtest's test_main()
530 convention, instead of running as a side-effect of merely being
531 imported. This allows these tests to be run in more natural and
532 flexible ways as unittests, outside the regrtest framework.
533
534- regrtest.py is much better integrated with unittest and doctest now,
535 especially in regard to reporting errors.
536
Tim Petersb07352e2001-09-08 01:25:47 +0000537Windows
538
Guido van Rossum624c8af2001-09-18 15:21:04 +0000539- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000540 that support it (NTFS under Windows 2000). See "What's New in
541 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000542
Tim Petersb07352e2001-09-08 01:25:47 +0000543
Tim Petersedc99312001-08-22 21:36:50 +0000544What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000545Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000546===========================
547
548Core
549
Tim Peters9fffa3e2001-09-04 05:14:19 +0000550- Conversion of long to float now raises OverflowError if the long is too
551 big to represent as a C double.
552
Tim Peters32f453e2001-09-03 08:35:41 +0000553- The 3-argument builtin pow() no longer allows a third non-None argument
554 if either of the first two arguments is a float, or if both are of
555 integer types and the second argument is negative (in which latter case
556 the arguments are converted to float, so this is really the same
557 restriction).
558
Tim Peters5d2b77c2001-09-03 05:47:38 +0000559- The builtin dir() now returns more information, and sometimes much
560 more, generally naming all attributes of an object, and all attributes
561 reachable from the object via its class, and from its class's base
562 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
563 an empty list. In 2.2a3,
564
565 >>> dir([])
566 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
567 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
568 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
569 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
570 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
571 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
572 'reverse', 'sort']
573
574 dir(module) continues to return only the module's attributes, though.
575
Tim Petersbdee63f2001-09-02 03:40:59 +0000576- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000577 than raising OverflowError. This is a partial implementation of PEP
578 237. You can use -Wdefault::OverflowWarning to enable a warning for
579 this situation, and -Werror::OverflowWarning to revert to the old
580 OverflowError exception.
581
Guido van Rossum61c345f2001-09-04 03:26:15 +0000582- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000583 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000584 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
585 -Qold, meaning the / operator has its classic meaning and no
586 warnings are issued. Using -Qwarn issues a run-time warning about
587 all uses of classic division for int and long arguments; -Qwarnall
588 also warns about classic division for float and complex arguments
589 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
590 new division by default, but only in the __main__ module. You can
591 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
592 __main__ module new division, and warns about classic division
593 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000594
Tim Petersbdee63f2001-09-02 03:40:59 +0000595- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000596 long, float, str, unicode, and tuple. (The types complex, list and
597 dictionary can also be subclassed; this was introduced earlier.)
598 Note that restrictions apply when subclassing immutable built-in
599 types: you can only affect the value of the instance by overloading
600 __new__. You can add mutable attributes, and the subclass instances
601 will have a __dict__ attribute, but you cannot change the "value"
602 (as implemented by the base class) of an immutable subclass instance
603 once it is created.
604
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000605- The dictionary constructor now takes an optional argument, a
606 mapping-like object, and initializes the dictionary from its
607 (key, value) pairs.
608
Tim Petersbdee63f2001-09-02 03:40:59 +0000609- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000610 "cooperative super calls" in a multiple inheritance setting. For an
611 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
612
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000613- A new built-in type, property, has been added. This enables the
614 creation of "properties". These are attributes implemented by
615 getter and setter functions (or only one of these for read-only or
616 write-only attributes), without the need to override __getattr__.
617 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000618
Tim Petersbdee63f2001-09-02 03:40:59 +0000619- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000620 liberalized, to allow leading zeroes. Examples of literals now
621 legal that were SyntaxErrors before:
622
623 00.0 0e3 0100j 07.5 00000000000000000008.
624
Tim Petersbdee63f2001-09-02 03:40:59 +0000625- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000626 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
627
Tim Petersedc99312001-08-22 21:36:50 +0000628Library
629
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000630- telnetlib includes symbolic names for the options, and support for
631 setting an option negotiation callback.
632
Tim Petersa40c7932001-09-05 22:36:56 +0000633- The new C standard no longer requires that math libraries set errno to
634 ERANGE on overflow. For platform libraries that exploit this new
635 freedom, Python's overflow-checking was wholly broken. A new overflow-
636 checking scheme attempts to repair that, but may not be reliable on all
637 platforms (C doesn't seem to provide anything both useful and portable
638 in this area anymore).
639
Martin v. Löwis44f86962001-09-05 13:44:54 +0000640- Asynchronous timeout actions are available through the new class
641 threading.Timer.
642
Tim Peters78526162001-09-05 00:53:45 +0000643- math.log and math.log10 now return sensible results for even huge
644 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
645
Tim Petersbdee63f2001-09-02 03:40:59 +0000646- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000647 currently held. See the docs for the imp module.
648
Tim Petersbdee63f2001-09-02 03:40:59 +0000649- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000650 dumps containing ints written on platforms where Python ints are 8 bytes.
651 When read on a box where Python ints are 4 bytes, such values are
652 converted to Python longs.
653
Tim Petersbdee63f2001-09-02 03:40:59 +0000654- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000655 code objects is no longer allowed. This plugs a security hole.
656
Steve Purcell6091cd62001-09-06 16:05:17 +0000657- unittest.TestResult instances no longer store references to tracebacks
658 generated by test failures. This prevents unexpected dangling references
659 to objects that should be garbage collected between tests.
660
Tim Petersedc99312001-08-22 21:36:50 +0000661Tools
662
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000663- Tools/scripts/fixdiv.py has been added which can be used to fix
664 division operators as per PEP 238.
665
Tim Petersedc99312001-08-22 21:36:50 +0000666Build
667
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000668- If you are an adventurous person using Mac OS X you may want to look at
669 Mac/OSX. There is a Makefile there that will build Python as a real Mac
670 application, which can be used for experimenting with Carbon or Cocoa.
671 Discussion of this on pythonmac-sig, please.
672
Tim Peters7eea37e2001-09-04 22:08:56 +0000673C API
674
675- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000676
Tim Peters9fffa3e2001-09-04 05:14:19 +0000677- Note that PyLong_AsDouble can fail! This has always been true, but no
678 callers checked for it. It's more likely to fail now, because overflow
679 errors are properly detected now. The proper way to check:
680
681 double x = PyLong_AsDouble(some_long_object);
682 if (x == -1.0 && PyErr_Occurred()) {
683 /* The conversion failed. */
684 }
685
Tim Petersbdee63f2001-09-02 03:40:59 +0000686- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000687 compile but will not participate in GC. To upgrade an extension
688 module:
689
690 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000691
Neil Schemenauer4042c692001-08-30 15:38:01 +0000692 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
693 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000694
Neil Schemenauer4042c692001-08-30 15:38:01 +0000695 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
696 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000697
Neil Schemenauer4042c692001-08-30 15:38:01 +0000698 - remove PyGC_HEAD_SIZE from object size calculations
699
700 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
701
Tim Petersbdee63f2001-09-02 03:40:59 +0000702- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000703 These can be used safely to construct string objects from a
704 sprintf-style format string (similar to the format string supported
705 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000706
Tim Petersedc99312001-08-22 21:36:50 +0000707New platforms
708
Tim Petersb7da0902001-09-02 23:01:43 +0000709- Stephen Hansen contributed patches sufficient to get a clean compile
710 under Borland C (Windows), but he reports problems running it and ran
711 out of time to complete the port. Volunteers? Expect a MemoryError
712 when importing the types module; this is probably shallow, and
713 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000714
Tim Petersedc99312001-08-22 21:36:50 +0000715Tests
716
717Windows
718
Tim Peters6e13a562001-09-06 00:32:15 +0000719- Large file support is now enabled on Win32 platforms as well as on
720 Win64. This means that, for example, you can use f.tell() and f.seek()
721 to manipulate files larger than 2 gigabytes (provided you have enough
722 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000723 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
724 filesize limit, and large file support makes no difference there.
725 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
726 NTFS has no practical limit on file size, and files of any size can be
727 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000728
Tim Petersbdee63f2001-09-02 03:40:59 +0000729- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000730 points to command.com (patch from Brian Quinlan).
731
Tim Petersedc99312001-08-22 21:36:50 +0000732
Tim Peters20f51a72001-07-21 02:31:40 +0000733What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000734Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000735===========================
736
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000737Build
738
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000739- Tim Peters developed a brand new Windows installer using Wise 8.1,
740 generously donated to us by Wise Solutions.
741
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000742- configure supports a new option --enable-unicode, with the values
743 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
744 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000745
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000746- A new configure option --enable-framework builds a Mac OS X framework,
747 which "make frameworkinstall" will install. This provides a starting
748 point for more mac-like functionality, join pythonmac-sig@python.org
749 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000750
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000751- The NeXT platform is no longer supported.
752
753- The `new' module is now statically linked.
754
Tim Peters0afb6092001-08-15 06:06:44 +0000755Tools
756
757- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000758 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000759 the module docstring for details.
760
Tim Peters20f51a72001-07-21 02:31:40 +0000761Tests
762
Tim Peters5e824c32001-08-12 22:25:01 +0000763- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000764 platforms, allowing to give clearer test result output. regrtest
765 also has optional --use/-u switch to run normally disabled tests
766 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000767
Tim Peters20f51a72001-07-21 02:31:40 +0000768- Several new tests in the standard test suite, with special thanks to
769 Nick Mathewson.
770
771Core
772
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000773- The floor division operator // has been added as outlined in PEP
774 238. The / operator still provides classic division (and will until
775 Python 3.0) unless "from __future__ import division" is included, in
776 which case the / operator will provide true division. The operator
777 module provides truediv() and floordiv() functions. Augmented
778 assignment variants are included, as are the equivalent overloadable
779 methods and C API methods. See the PEP for a full discussion:
780 <http://python.sf.net/peps/pep-0238.html>
781
Tim Peters6cd6a822001-08-17 22:11:27 +0000782- Future statements are now effective in simulated interactive shells
783 (like IDLE). This should "just work" by magic, but read Michael
784 Hudson's "Future statements in simulated shells" PEP 264 for full
785 details: <http://python.sf.net/peps/pep-0264.html>.
786
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000787- The type/class unification (PEP 252-253) was integrated into the
788 trunk and is not so tentative any more (the exact specification of
789 some features is still tentative). A lot of work has done on fixing
790 bugs and adding robustness and features (performance still has to
791 come a long way).
792
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000793- Warnings about a mismatch in the Python API during extension import
794 now use the Python warning framework (which makes it possible to
795 write filters for these warnings).
796
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000797- A function's __dict__ (aka func_dict) will now always be a
798 dictionary. It used to be possible to delete it or set it to None,
799 but now both actions raise TypeErrors. It is still legal to set it
800 to a dictionary object. Getting func.__dict__ before any attributes
801 have been assigned now returns an empty dictionary instead of None.
802
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000803- A new command line option, -E, was added which disables the use of
804 all environment variables, or at least those that are specifically
805 significant to Python. Usually those have a name starting with
806 "PYTHON". This was used to fix a problem where the tests fail if
807 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
808 older distribution.
809
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000810Library
811
Tim Peters5e824c32001-08-12 22:25:01 +0000812- New class Differ and new functions ndiff() and restore() in difflib.py.
813 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000814 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000815
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000816- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
817 value using the minimal quoting required for the value; more
818 reliable than using xml.sax.saxutils.escape() for attribute values.
819
820- Readline completion support for cmd.Cmd was added.
821
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000822- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
823
824- Added function threading.BoundedSemaphore()
825
826- Added Ka-Ping Yee's cgitb.py module.
827
828- The `new' module now exposes the CO_xxx flags.
829
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000830New platforms
831
832C API
833
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000834- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
835 which provide a cross-platform implementations for the
836 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
837 the standard sprintf() and vsprintf() C lib APIs, these versions
838 apply bounds checking on the used buffer which enhances protection
839 against buffer overruns.
840
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000841- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000842 and extensions using different Unicode widths is rendered next to
843 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000844 will result in an ImportError. Unicode extensions writers must make
845 sure to check the Unicode width compatibility in their extensions by
846 using at least one of the mangled Unicode APIs in the extension.
847
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000848- Two new flags METH_NOARGS and METH_O are available in method definition
849 tables to simplify implementation of methods with no arguments and a
850 single untyped argument. Calling such methods is more efficient than
851 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
852 deprecated.
853
Tim Petersc1731372001-08-04 08:12:36 +0000854Windows
855
856- "import module" now compiles module.pyw if it exists and nothing else
857 relevant is found.
858
Tim Peters20f51a72001-07-21 02:31:40 +0000859
Guido van Rossum55a78992001-07-17 17:22:32 +0000860What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000861Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000862===========================
863
864Core
Tim Petersa814db52001-05-14 07:05:58 +0000865
Tim Peters6d6c1a32001-08-02 04:15:00 +0000866- TENTATIVELY, a large amount of code implementing much of what's
867 described in PEP 252 (Making Types Look More Like Classes) and PEP
868 253 (Subtyping Built-in Types) was added. This will be released
869 with Python 2.2a1. Documentation will be provided separately
870 through http://www.python.org/2.2/. The purpose of releasing this
871 with Python 2.2a1 is to test backwards compatibility. It is
872 possible, though not likely, that a decision is made not to release
873 this code as part of 2.2 final, if any serious backwards
874 incompapatibilities are found during alpha testing that cannot be
875 repaired.
876
Guido van Rossum55a78992001-07-17 17:22:32 +0000877- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000878 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000879 more 'yield' statements. See PEP 255. Since this adds a new
880 keyword to the language, this feature must be enabled by including a
881 future statement: "from __future__ import generators" (see PEP 236).
882 Generators will become a standard feature in a future release
883 (probably 2.3). Without this future statement, 'yield' remains an
884 ordinary identifier, but a warning is issued each time it is used.
885 (These warnings currently don't conform to the warnings framework of
886 PEP 230; we intend to fix this in 2.2a2.)
887
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000888- The UTF-16 codec was modified to be more RFC compliant. It will now
889 only remove BOM characters at the start of the string and then
890 only if running in native mode (UTF-16-LE and -BE won't remove a
891 leading BMO character).
892
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000893- Strings now have a new method .decode() to complement the already
894 existing .encode() method. These two methods provide direct access
895 to the corresponding decoders and encoders of the registered codecs.
896
897 To enhance the usability of the .encode() method, the special
898 casing of Unicode object return values was dropped (Unicode objects
899 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000900
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000901 Both methods will now return whatever the codec in charge of the
902 requested encoding returns as object, e.g. Unicode codecs will
903 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
904 will return u"äöü"). This enables codec writer to create codecs
905 for various simple to use conversions.
906
907 New codecs were added to demonstrate these new features (the .encode()
908 and .decode() columns indicate the type of the returned objects):
909
910 Name | .encode() | .decode() | Description
911 ----------------------------------------------------------------------
912 uu | string | string | UU codec (e.g. for email)
913 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000914 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000915 zlib | string | string | zlib compression
916 hex | string | string | 2-byte hex codec
917 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
918
Mark Hammond2a0af792001-05-14 03:09:36 +0000919- Some operating systems now support the concept of a default Unicode
920 encoding for file system operations. Notably, Windows supports 'mbcs'
921 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000922 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000923 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000924
925 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000926 functions that return filenames (such as os.listdir()) to return Python
927 string objects pre-encoded using the default file system encoding for
928 the platform. As this encoding is likely to be different from Python's
929 default encoding, converting this name to a Unicode object before passing
930 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000931 would attempt to use its default encoding (generally ASCII) rather than
932 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000933
Tim Petersa814db52001-05-14 07:05:58 +0000934 In general, this change simply removes surprises when working with
935 Unicode and the file system, making these operations work as you expect,
936 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000937 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000938
Tim Peters61dff2b2001-05-08 15:43:37 +0000939- Float (and complex) literals in source code were evaluated to full
940 precision only when running from a .py file; the same code loaded from a
941 .pyc (or .pyo) file could suffer numeric differences starting at about the
942 12th significant decimal digit. For example, on a machine with IEEE-754
943 floating arithmetic,
944
945 x = 9007199254740992.0
946 print long(x)
947
948 printed 9007199254740992 if run directly from .py, but 9007199254740000
949 if from a compiled (.pyc or .pyo) file. This was due to marshal using
950 str(float) instead of repr(float) when building code objects. marshal
951 now uses repr(float) instead, which should reproduce floats to full
952 machine precision (assuming the platform C float<->string I/O conversion
953 functions are of good quality).
954
955 This may cause floating-point results to change in some cases, and
956 usually for the better, but may also cause numerically unstable
957 algorithms to break.
958
Tim Peters2f228e72001-05-13 00:19:31 +0000959- The implementation of dicts suffers fewer collisions, which has speed
960 benefits. However, the order in which dict entries appear in dict.keys(),
961 dict.values() and dict.items() may differ from previous releases for a
962 given dict. Nothing is defined about this order, so no program should
963 rely on it. Nevertheless, it's easy to write test cases that rely on the
964 order by accident, typically because of printing the str() or repr() of a
965 dict to an "expected results" file. See Lib/test/test_support.py's new
966 sortdict(dict) function for a simple way to display a dict in sorted
967 order.
968
Tim Peters7a3bfc32001-06-12 01:22:22 +0000969- Many other small changes to dicts were made, resulting in faster
970 operation along the most common code paths.
971
Guido van Rossum10315822001-05-01 20:54:30 +0000972- Dictionary objects now support the "in" operator: "x in dict" means
973 the same as dict.has_key(x).
974
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000975- The update() method of dictionaries now accepts generic mapping
976 objects. Specifically the argument object must support the .keys()
977 and __getitem__() methods. This allows you to say, for example,
978 {}.update(UserDict())
979
Guido van Rossum10315822001-05-01 20:54:30 +0000980- Iterators were added; this is a generalized way of providing values
981 to a for loop. See PEP 234. There's a new built-in function iter()
982 to return an iterator. There's a new protocol to get the next value
983 from an iterator using the next() method (in Python) or the
984 tp_iternext slot (in C). There's a new protocol to get iterators
985 using the __iter__() method (in Python) or the tp_iter slot (in C).
986 Iterating (i.e. a for loop) over a dictionary generates its keys.
987 Iterating over a file generates its lines.
988
Tim Petersf553f892001-05-01 20:45:31 +0000989- The following functions were generalized to work nicely with iterator
990 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000991 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000992 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
993 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000994 join() method of strings
995 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000996 'x in y' and 'x not in y' (PySequence_Contains() in C API)
997 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000998 right-hand side of assignment statements with multiple targets, such as
999 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001000
Tim Petersd85e1022001-05-11 21:51:48 +00001001- Accessing module attributes is significantly faster (for example,
1002 random.random or os.path or yourPythonModule.yourAttribute).
1003
Tim Peterse63415e2001-05-08 04:38:29 +00001004- Comparing dictionary objects via == and != is faster, and now works even
1005 if the keys and values don't support comparisons other than ==.
1006
Tim Peters95bf9392001-05-10 08:32:44 +00001007- Comparing dictionaries in ways other than == and != is slower: there were
1008 insecurities in the dict comparison implementation that could cause Python
1009 to crash if the element comparison routines for the dict keys and/or
1010 values mutated the dicts. Making the code bulletproof slowed it down.
1011
Tim Peterseb28ef22001-06-02 05:27:19 +00001012- Collisions in dicts are resolved via a new approach, which can help
1013 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001014 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001015 faster now. Thanks to Christian Tismer for pointing out the cause and
1016 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001017
Tim Peters52e155e2001-06-16 05:42:57 +00001018- repr() is much faster for large containers (dict, list, tuple).
1019
1020
Tim Petersa814db52001-05-14 07:05:58 +00001021Library
1022
Fred Drake960fdf92001-07-20 18:38:26 +00001023- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1024 were added to the string module. These a locale-indenpendent
1025 constants, unlike letters, lowercase, and uppercase. These are now
1026 use in appropriate locations in the standard library.
1027
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001028- The flags used in dlopen calls can now be configured using
1029 sys.setdlopenflags and queried using sys.getdlopenflags.
1030
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001031- Fredrik Lundh's xmlrpclib is now a standard library module. This
1032 provides full client-side XML-RPC support. In addition,
1033 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1034 one asyncore-based). Thanks to Eric Raymond for the documentation.
1035
Guido van Rossum643d3912001-07-05 14:46:25 +00001036- The xrange() object is simplified: it no longer supports slicing,
1037 repetition, comparisons, efficient 'in' checking, the tolist()
1038 method, or the start, stop and step attributes. See PEP 260.
1039
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001040- A new function fnmatch.filter to filter lists of file names was added.
1041
Barry Warsawffd674d2001-05-22 16:00:10 +00001042- calendar.py uses month and day names based on the current locale.
1043
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001044- strop is now *really* obsolete (this was announced before with 1.6),
1045 and issues DeprecationWarning when used (except for the four items
1046 that are still imported into string.py).
1047
Tim Petersa814db52001-05-14 07:05:58 +00001048- Cookie.py now sorts key+value pairs by key in output strings.
1049
1050- pprint.isrecursive(object) didn't correctly identify recursive objects.
1051 Now it does.
1052
Tim Peters95b3f782001-05-14 18:39:41 +00001053- pprint functions now much faster for large containers (tuple, list, dict).
1054
Tim Peters7b9542a2001-06-10 23:40:19 +00001055- New 'q' and 'Q' format codes in the struct module, corresponding to C
1056 types "long long" and "unsigned long long" (on Windows, __int64). In
1057 native mode, these can be used only when the platform C compiler supports
1058 these types (when HAVE_LONG_LONG is #define'd by the Python config
1059 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001060 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1061 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001062
Guido van Rossum83213cc2001-06-12 16:48:52 +00001063- The site module installs a new built-in function 'help' that invokes
1064 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1065 it displays a message reminding the user to use 'help()' or
1066 'help(object)'.
1067
Tim Petersa814db52001-05-14 07:05:58 +00001068Tests
1069
1070- New test_mutants.py runs dict comparisons where the key and value
1071 comparison operators mutute the dicts randomly during comparison. This
1072 rapidly causes Python to crash under earlier releases (not for the faint
1073 of heart: it can also cause Win9x to freeze or reboot!).
1074
1075- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001076 pprint.isreadable() return sensible results. Also verifies that simple
1077 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001078
Tim Peters4324aa32001-05-28 22:30:08 +00001079C API
1080
1081- Removed the unused last_is_sticky argument from the internal
1082 _PyTuple_Resize(). If this affects you, you were cheating.
1083
1084
Guido van Rossum55a78992001-07-17 17:22:32 +00001085======================================================================
1086
1087
Guido van Rossumffe13be2001-04-16 18:46:45 +00001088What's New in Python 2.1 (final)?
1089=================================
1090
1091We only changed a few things since the last release candidate, all in
1092Python library code:
1093
1094- A bug in the locale module was fixed that affected locales which
1095 define no grouping for numeric formatting.
1096
1097- A few bugs in the weakref module's implementations of weak
1098 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1099 and the test suite was updated to check for these bugs.
1100
1101- An old bug in the os.path.walk() function (introduced in Python
1102 2.0!) was fixed: a non-existent file would cause an exception
1103 instead of being ignored.
1104
1105- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1106 PyChecker.
1107
1108
Guido van Rossum5b08f132001-04-16 02:05:23 +00001109What's New in Python 2.1c2?
1110===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001111
Guido van Rossum5b08f132001-04-16 02:05:23 +00001112A flurry of small changes, and one showstopper fixed in the nick of
1113time made it necessary to release another release candidate. The list
1114here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001115
Guido van Rossum5b08f132001-04-16 02:05:23 +00001116Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001117
Guido van Rossum5b08f132001-04-16 02:05:23 +00001118- Tim discovered a nasty bug in the dictionary code, caused by
1119 PyDict_Next() calling dict_resize(), and the GC code's use of
1120 PyDict_Next() violating an assumption in dict_items(). This was
1121 fixed with considerable amounts of band-aid, but the net effect is a
1122 saner and more robust implementation.
1123
1124- Made a bunch of symbols static that were accidentally global.
1125
1126Build and Ports
1127
1128- The setup.py script didn't check for a new enough version of zlib
1129 (1.1.3 is needed). Now it does.
1130
1131- Changed "make clean" target to also remove shared libraries.
1132
1133- Added a more general warning about the SGI Irix optimizer to README.
1134
1135Library
1136
1137- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1138 omitted the slash between host and file.html.
1139
1140- The mailbox module's _Mailbox class contained a completely broken
1141 and undocumented seek() method. Ripped it out.
1142
1143- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1144 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1145
1146- Fixed a few last-minute bugs in unittest.
1147
1148Extensions
1149
1150- Reverted the patch to the OpenSSL code in socketmodule.c to support
1151 RAND_status() and the EGD, and the subsequent patch that tried to
1152 fix it for pre-0.9.5 versions; the problem with the patch is that on
1153 some systems it issues a warning whenever socket is imported, and
1154 that's unacceptable.
1155
1156Tests
1157
1158- Fixed the pickle tests to work with "import test.test_pickle".
1159
1160- Tweaked test_locale.py to actually run the test Windows.
1161
1162- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1163 not "wb" (which is not a valid mode at all).
1164
1165- Fix pstats browser crashes. Import readline if it exists to make
1166 the user interface nicer.
1167
1168- Add "import thread" to the top of test modules that import the
1169 threading module (test_asynchat and test_threadedtempfile). This
1170 prevents test failures caused by a broken threading module resulting
1171 from a previously caught failed import.
1172
1173- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1174 needed on some platforms (e.g. Solaris 8) when the tests are run
1175 twice in succession.
1176
1177- Skip rather than fail test_sunaudiodev if no audio device is found.
1178
1179
1180What's New in Python 2.1c1?
1181===========================
1182
1183This list was significantly updated when 2.1c2 was released; the 2.1c1
1184release didn't mention most changes that were actually part of 2.1c1:
1185
1186Legal
1187
1188- Copyright was assigned to the Python Software Foundation (PSF) and a
1189 PSF license (very similar to the CNRI license) was added.
1190
1191- The CNRI copyright notice was updated to include 2001.
1192
1193Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001194
Guido van Rossumc9932722001-04-12 02:31:27 +00001195- After a public outcry, assignment to __debug__ is no longer illegal;
1196 instead, a warning is issued. It will become illegal in 2.2.
1197
Guido van Rossum5b08f132001-04-16 02:05:23 +00001198- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1199 "%#x" now always prepends "0x", even if the value is zero.
1200
1201- Fixed some nits in the bytecode compiler.
1202
1203- Fixed core dumps when calling certain kinds of non-functions.
1204
1205- Fixed various core dumps caused by reference count bugs.
1206
1207Build and Ports
1208
1209- Use INSTALL_SCRIPT to install script files.
1210
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001211- New port: SCO Unixware 7, by Billy G. Allie.
1212
Guido van Rossum5b08f132001-04-16 02:05:23 +00001213- Updated RISCOS port.
1214
1215- Updated BeOS port and notes.
1216
1217- Various other porting problems resolved.
1218
1219Library
1220
1221- The TERMIOS and SOCKET modules are now truly obsolete and
1222 unnecessary. Their symbols are incorporated in the termios and
1223 socket modules.
1224
1225- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1226 better tests for pickling.
1227
1228- threading: make Condition.wait() robust against KeyboardInterrupt.
1229
1230- zipfile: add support to zipfile to support opening an archive
1231 represented by an open file rather than a file name. Fix bug where
1232 the archive was not properly closed. Fixed a bug in this bugfix
1233 where flush() was called for a read-only file.
1234
1235- imputil: added an uninstall() method to the ImportManager.
1236
1237- Canvas: fixed bugs in lower() and tkraise() methods.
1238
1239- SocketServer: API change (added overridable close_request() method)
1240 so that the TCP server can explicitly close the request.
1241
1242- pstats: Eric Raymond added a simple interactive statistics browser,
1243 invoked when the module is run as a script.
1244
1245- locale: fixed a problem in format().
1246
1247- webbrowser: made it work when the BROWSER environment variable has a
1248 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1249 KDE 2. Fixed some other nits.
1250
1251- unittest: changes to allow using a different exception than
1252 AssertionError, and added a few more function aliases. Some other
1253 small changes.
1254
1255- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1256
1257- asynchat: fixed a critical bug in asynchat that slipped through the
1258 2.1b2 release. Fixed another rare bug.
1259
1260- Fix some unqualified except: clauses (always a bad code example).
1261
1262XML
1263
1264- pyexpat: new API get_version_string().
1265
1266- Fixed some minidom bugs.
1267
1268Extensions
1269
1270- Fixed a core dump in _weakref. Removed the weakref.mapping()
1271 function (it adds nothing to the API).
1272
1273- Rationalized the use of header files in the readline module, to make
1274 it compile (albeit with some warnings) with the very recent readline
1275 4.2, without breaking for earlier versions.
1276
1277- Hopefully fixed a buffering problem in linuxaudiodev.
1278
1279- Attempted a fix to make the OpenSSL support in the socket module
1280 work again with pre-0.9.5 versions of OpenSSL.
1281
1282Tests
1283
1284- Added a test case for asynchat and asyncore.
1285
1286- Removed coupling between tests where one test failing could break
1287 another.
1288
1289Tools
1290
1291- Ping added an interactive help browser to pydoc, fixed some nits
1292 in the rest of the pydoc code, and added some features to his
1293 inspect module.
1294
1295- An updated python-mode.el version 4.1 which integrates Ken
1296 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1297 much nicer in XEmacs and Emacs. When stepping through your program
1298 with pdb, in either the shell window or the *Python* window, the
1299 source file and line will be tracked by an arrow. Very cool!
1300
1301- IDLE: syntax warnings in interactive mode are changed into errors.
1302
1303- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001304 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001305
1306- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001307
Barry Warsaw11e89c72001-04-11 20:37:57 +00001308
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001309What's New in Python 2.1 beta 2?
1310================================
1311
Guido van Rossum053ae352001-03-22 14:17:21 +00001312(Unlisted are many fixed bugs, more documentation, etc.)
1313
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001314Core language, builtins, and interpreter
1315
Guido van Rossum053ae352001-03-22 14:17:21 +00001316- The nested scopes work (enabled by "from __future__ import
1317 nested_scopes") is completed; in particular, the future now extends
1318 into code executed through exec, eval() and execfile(), and into the
1319 interactive interpreter.
1320
1321- When calling a base class method (e.g. BaseClass.__init__(self)),
1322 this is now allowed even if self is not strictly spoken a class
1323 instance (e.g. when using metaclasses or the Don Beaudry hook).
1324
1325- Slice objects are now comparable but not hashable; this prevents
1326 dict[:] from being accepted but meaningless.
1327
1328- Complex division is now calculated using less braindead algorithms.
1329 This doesn't change semantics except it's more likely to give useful
1330 results in extreme cases. Complex repr() now uses full precision
1331 like float repr().
1332
1333- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1334
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001335- It is illegal to assign to the name __debug__, which is set when the
1336 interpreter starts. It is effectively a compile-time constant.
1337
1338- A warning will be issued if a global statement for a variable
1339 follows a use or assignment of that variable.
1340
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001341Standard library
1342
Guido van Rossum053ae352001-03-22 14:17:21 +00001343- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1344 inspired by JUnit), is now part of the standard library. You now
1345 have a choice of two testing frameworks: unittest requires you to
1346 write testcases as separate code, doctest gathers them from
1347 docstrings. Both approaches have their advantages and
1348 disadvantages.
1349
1350- A new module Tix was added, which wraps the Tix extension library
1351 for Tk. With that module, it is not necessary to statically link
1352 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1353 require" command. See Demo/tix/.
1354
1355- tzparse.py is now obsolete.
1356
1357- In gzip.py, the seek() and tell() methods are removed -- they were
1358 non-functional anyway, and it's better if callers can test for their
1359 existence with hasattr().
1360
1361Python/C API
1362
1363- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1364 that's already in the dictionary during a PyDict_Next() iteration.
1365 This used to fail occasionally when a dictionary resize operation
1366 could be triggered that would rehash all the keys. All other
1367 modifications to the dictionary are still off-limits during a
1368 PyDict_Next() iteration!
1369
1370- New extended APIs related to passing compiler variables around.
1371
1372- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1373 implement isinstance() and issubclass().
1374
1375- Py_BuildValue() now has a "D" conversion to create a Python complex
1376 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001377
Fred Drake4e262a92001-03-22 18:26:47 +00001378- Extensions types which support weak references must now set the
1379 field allocated for the weak reference machinery to NULL themselves;
1380 this is done to avoid the cost of checking each object for having a
1381 weakly referencable type in PyObject_INIT(), since most types are
1382 not weakly referencable.
1383
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001384- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1385 free variables and cell variables to and from the frame's f_locals.
1386
1387- Variants of several functions defined in pythonrun.h have been added
1388 to support the nested_scopes future statement. The variants all end
1389 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1390 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1391 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001392 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001393
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001394Distutils
1395
1396- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1397 into the release tree.
1398
Tim Peters0e57abf2001-05-02 07:39:38 +00001399- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001400 (an uninstaller, more customization of the installer's display)
1401
1402- from Jack Jansen: added Mac-specific code to generate a dialog for
1403 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001404 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001405 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001406
1407- added 'platforms' and 'keywords' to the set of metadata that can be
1408 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001409
1410- applied patches from Jason Tishler to make the compiler class work with
1411 Cygwin.
1412
1413
Tim Peters2fe289a2001-03-01 22:19:38 +00001414What's New in Python 2.1 beta 1?
1415================================
Tim Petersd66595f2001-02-04 03:09:53 +00001416
1417Core language, builtins, and interpreter
1418
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001419- Following an outcry from the community about the amount of code
1420 broken by the nested scopes feature introduced in 2.1a2, we decided
1421 to make this feature optional, and to wait until Python 2.2 (or at
1422 least 6 months) to make it standard. The option can be enabled on a
1423 per-module basis by adding "from __future__ import nested_scopes" at
1424 the beginning of a module (before any other statements, but after
1425 comments and an optional docstring). See PEP 236 (Back to the
1426 __future__) for a description of the __future__ statement. PEP 227
1427 (Statically Nested Scopes) has been updated to reflect this change,
1428 and to clarify the semantics in a number of endcases.
1429
1430- The nested scopes code, when enabled, has been hardened, and most
1431 bugs and memory leaks in it have been fixed.
1432
1433- Compile-time warnings are now generated for a number of conditions
1434 that will break or change in meaning when nested scopes are enabled:
1435
1436 - Using "from...import *" or "exec" without in-clause in a function
1437 scope that also defines a lambda or nested function with one or
1438 more free (non-local) variables. The presence of the import* or
1439 bare exec makes it impossible for the compiler to determine the
1440 exact set of local variables in the outer scope, which makes it
1441 impossible to determine the bindings for free variables in the
1442 inner scope. To avoid the warning about import *, change it into
1443 an import of explicitly name object, or move the import* statement
1444 to the global scope; to avoid the warning about bare exec, use
1445 exec...in... (a good idea anyway -- there's a possibility that
1446 bare exec will be deprecated in the future).
1447
1448 - Use of a global variable in a nested scope with the same name as a
1449 local variable in a surrounding scope. This will change in
1450 meaning with nested scopes: the name in the inner scope will
1451 reference the variable in the outer scope rather than the global
1452 of the same name. To avoid the warning, either rename the outer
1453 variable, or use a global statement in the inner function.
1454
Neil Schemenauera35c6882001-02-27 04:45:05 +00001455- An optional object allocator has been included. This allocator is
1456 optimized for Python objects and should be faster and use less memory
1457 than the standard system allocator. It is not enabled by default
1458 because of possible thread safety problems. The allocator is only
1459 protected by the Python interpreter lock and it is possible that some
1460 extension modules require a thread safe allocator. The object
1461 allocator can be enabled by providing the "--with-pymalloc" option to
1462 configure.
1463
Tim Petersd66595f2001-02-04 03:09:53 +00001464Standard library
1465
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001466- pyexpat now detects the expat version if expat.h defines it. A
1467 number of additional handlers are provided, which are only available
1468 since expat 1.95. In addition, the methods SetParamEntityParsing and
1469 GetInputContext of Parser objects are available with 1.95.x
1470 only. Parser objects now provide the ordered_attributes and
1471 specified_attributes attributes. A new module expat.model was added,
1472 which offers a number of additional constants if 1.95.x is used.
1473
1474- xml.dom offers the new functions registerDOMImplementation and
1475 getDOMImplementation.
1476
1477- xml.dom.minidom offers a toprettyxml method. A number of DOM
1478 conformance issues have been resolved. In particular, Element now
1479 has an hasAttributes method, and the handling of namespaces was
1480 improved.
1481
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001482- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1483 getting information about live Python code, and pydoc.py, a module
1484 for interactively converting docstrings to HTML or text.
1485 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001486 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001487 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1488 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001489
Tim Peters1eff7962001-03-01 02:31:33 +00001490- New library module difflib.py, primarily packaging the SequenceMatcher
1491 class at the heart of the popular ndiff.py file-comparison tool.
1492
1493- doctest.py (a framework for verifying Python code examples in docstrings)
1494 is now part of the std library.
1495
Tim Petersd66595f2001-02-04 03:09:53 +00001496Windows changes
1497
Guido van Rossume3955a82001-03-02 14:05:59 +00001498- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1499 small GUI that lets you browse the module docstrings using your
1500 default web browser.
1501
Tim Peters1eff7962001-03-01 02:31:33 +00001502- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1503 Platforms) is implemented. See
1504
1505 http://python.sourceforge.net/peps/pep-0235.html
1506
1507 for full details, especially the "Current Lower-Left Semantics" section.
1508 The new Windows import rules are simpler than before:
1509
1510 A. If the PYTHONCASEOK environment variable exists, same as
1511 before: silently accept the first case-insensitive match of any
1512 kind; raise ImportError if none found.
1513
1514 B. Else search sys.path for the first case-sensitive match; raise
1515 ImportError if none found.
1516
1517 The same rules have been implented on other platforms with case-
1518 insensitive but case-preserving filesystems too (including Cygwin, and
1519 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001520
Tim Peters25a9ce32001-02-19 07:06:36 +00001521- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1522 what it's supposed to do (and does do under NT and 2000) via direct
1523 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001524 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001525 all Win9x systems before.
1526
Tim Peters1eff7962001-03-01 02:31:33 +00001527- Build: Subproject _test (effectively) renamed to _testcapi.
1528
Tim Peters2fe289a2001-03-01 22:19:38 +00001529New platforms
1530
1531- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1532 Thanks to Steven Majewski!
1533
1534- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1535 Tishler!
1536
Guido van Rossum9089b272001-03-02 06:49:50 +00001537- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1538 Schwertberger! See RISCOS/README for more information -- it seems
1539 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001540 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001541
Tim Peters25a9ce32001-02-19 07:06:36 +00001542
Tim Petersd7b5e882001-01-25 03:36:26 +00001543What's New in Python 2.1 alpha 2?
1544=================================
Tim Peters40ead762001-01-27 05:35:26 +00001545
Tim Petersd7b5e882001-01-25 03:36:26 +00001546Core language, builtins, and interpreter
1547
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001548- Scopes nest. If a name is used in a function or class, but is not
1549 local, the definition in the nearest enclosing function scope will
1550 be used. One consequence of this change is that lambda statements
1551 could reference variables in the namespaces where the lambda is
1552 defined. In some unusual cases, this change will break code.
1553
1554 In all previous version of Python, names were resolved in exactly
1555 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001556 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001557 function A is defined within a function B, the names bound in B are
1558 not visible in A. The new rules make names bound in B visible in A,
1559 unless A contains a name binding that hides the binding in B.
1560
1561 Section 4.1 of the reference manual describes the new scoping rules
1562 in detail. The test script in Lib/test/test_scope.py demonstrates
1563 some of the effects of the change.
1564
1565 The new rules will cause existing code to break if it defines nested
1566 functions where an outer function has local variables with the same
1567 name as globals or builtins used by the inner function. Example:
1568
1569 def munge(str):
1570 def helper(x):
1571 return str(x)
1572 if type(str) != type(''):
1573 str = helper(str)
1574 return str.strip()
1575
1576 Under the old rules, the name str in helper() is bound to the
1577 builtin function str(). Under the new rules, it will be bound to
1578 the argument named str and an error will occur when helper() is
1579 called.
1580
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001581- The compiler will report a SyntaxError if "from ... import *" occurs
1582 in a function or class scope. The language reference has documented
1583 that this case is illegal, but the compiler never checked for it.
1584 The recent introduction of nested scope makes the meaning of this
1585 form of name binding ambiguous. In a future release, the compiler
1586 may allow this form when there is no possibility of ambiguity.
1587
Tim Peters40ead762001-01-27 05:35:26 +00001588- repr(string) is easier to read, now using hex escapes instead of octal,
1589 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1590
1591 >>> "\texample \r\n" + chr(0) + chr(255)
1592 '\texample \r\n\x00\xff' # in 2.1
1593 '\011example \015\012\000\377' # in 2.0
1594
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001595- Functions are now compared and hashed by identity, not by value, since
1596 the func_code attribute is writable.
1597
Fred Drakefb9d7122001-02-01 20:00:40 +00001598- Weak references (PEP 205) have been added. This involves a few
1599 changes in the core, an extension module (_weakref), and a Python
1600 module (weakref). The weakref module is the public interface. It
1601 includes support for "explicit" weak references, proxy objects, and
1602 mappings with weakly held values.
1603
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001604- A 'continue' statement can now appear in a try block within the body
1605 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001606 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001607
Tim Petersd7b5e882001-01-25 03:36:26 +00001608Standard library
1609
Barry Warsaw30dbd142001-01-31 22:14:01 +00001610- mailbox.py now has a new class, PortableUnixMailbox which is
1611 identical to UnixMailbox but uses a more portable scheme for
1612 determining From_ separators. Also, the constructors for all the
1613 classes in this module have a new optional `factory' argument, which
1614 is a callable used when new message classes must be instantiated by
1615 the next() method.
1616
Tim Petersd7b5e882001-01-25 03:36:26 +00001617- random.py is now self-contained, and offers all the functionality of
1618 the now-deprecated whrandom.py. See the docs for details. random.py
1619 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001620 and restoring the internal state of the generator; and jumpahead(n),
1621 for quickly forcing the internal state to be the same as if n calls to
1622 random() had been made. The latter is particularly useful for multi-
1623 threaded programs, creating one instance of the random.Random() class for
1624 each thread, then using .jumpahead() to force each instance to use a
1625 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001626
Tim Peters0de88fc2001-02-01 04:59:18 +00001627- random.py's seed() function is new. For bit-for-bit compatibility with
1628 prior releases, use the whseed function instead. The new seed function
1629 addresses two problems: (1) The old function couldn't produce more than
1630 about 2**24 distinct internal states; the new one about 2**45 (the best
1631 that can be done in the Wichmann-Hill generator). (2) The old function
1632 sometimes produced identical internal states when passed distinct
1633 integers, and there was no simple way to predict when that would happen;
1634 the new one guarantees to produce distinct internal states for all
1635 arguments in [0, 27814431486576L).
1636
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001637- The socket module now supports raw packets on Linux. The socket
1638 family is AF_PACKET.
1639
Tim Peters9ea17ac2001-02-02 05:57:15 +00001640- test_capi.py is a start at running tests of the Python C API. The tests
1641 are implemented by the new Modules/_testmodule.c.
1642
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001643- A new extension module, _symtable, provides provisional access to the
1644 internal symbol table used by the Python compiler. A higher-level
1645 interface will be added on top of _symtable in a future release.
1646
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001647- Removed the obsolete soundex module.
1648
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001649- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1650 the isSameNode method; NamedNodeMap the get method.
1651
1652- xml.sax.expatreader supports the lexical handler property; it
1653 generates comment, startCDATA, and endCDATA events.
1654
Tim Petersee826f82001-01-31 19:39:44 +00001655Windows changes
1656
1657- Build procedure: the zlib project is built in a different way that
1658 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001659 the zlib binary used. See PCbuild\readme.txt for details. Your old
1660 zlib-related directories can be deleted; you'll need to download fresh
1661 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001662
Tim Peters9ea17ac2001-02-02 05:57:15 +00001663- Build: New subproject _test for the benefit of test_capi.py (see above).
1664
Tim Petersb16c56f2001-02-02 21:24:51 +00001665- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1666 interface to some Python compiler internals).
1667
1668- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001669 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001670
Tim Petersa3a3a032000-11-30 05:22:44 +00001671What's New in Python 2.1 alpha 1?
1672=================================
1673
1674Core language, builtins, and interpreter
1675
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001676- There is a new Unicode companion to the PyObject_Str() API
1677 called PyObject_Unicode(). It behaves in the same way as the
1678 former, but assures that the returned value is an Unicode object
1679 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001680
Guido van Rossumf98eda02001-01-17 15:54:45 +00001681- The comparison operators support "rich comparison overloading" (PEP
1682 207). C extension types can provide a rich comparison function in
1683 the new tp_richcompare slot in the type object. The cmp() function
1684 and the C function PyObject_Compare() first try the new rich
1685 comparison operators before trying the old 3-way comparison. There
1686 is also a new C API PyObject_RichCompare() (which also falls back on
1687 the old 3-way comparison, but does not constrain the outcome of the
1688 rich comparison to a Boolean result).
1689
1690 The rich comparison function takes two objects (at least one of
1691 which is guaranteed to have the type that provided the function) and
1692 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1693 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1694 object, which may be NotImplemented (in which case the tp_compare
1695 slot function is used as a fallback, if defined).
1696
1697 Classes can overload individual comparison operators by defining one
1698 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001699 __ge__. There are no explicit "reflected argument" versions of
1700 these; instead, __lt__ and __gt__ are each other's reflection,
1701 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1702 reflection (similar at the C level). No other implications are
1703 made; in particular, Python does not assume that == is the Boolean
1704 inverse of !=, or that < is the Boolean inverse of >=. This makes
1705 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001706
1707 Classes or types that want to implement (in)equality tests but not
1708 the ordering operators (i.e. unordered types) should implement ==
1709 and !=, and raise an error for the ordering operators.
1710
Guido van Rossuma88479f2001-01-18 14:28:08 +00001711 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001712 Boolean; e.g. a matrix type might want to return a matrix of bits
1713 for A < B, giving elementwise comparisons. Such types should ensure
1714 that any interpretation of their value in a Boolean context raises
1715 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1716 at the C level) to always raise an exception.
1717
Guido van Rossuma88479f2001-01-18 14:28:08 +00001718- Complex numbers use rich comparisons to define == and != but raise
1719 an exception for <, <=, > and >=. Unfortunately, this also means
1720 that cmp() of two complex numbers raises an exception when the two
1721 numbers differ. Since it is not mathematically meaningful to compare
1722 complex numbers except for equality, I hope that this doesn't break
1723 too much code.
1724
Tim Peters3389f192001-02-18 08:48:49 +00001725- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001726 not defined by the language, other than that it's arbitrary but
1727 consistent (see the Reference Manual). An implementation detail changed
1728 in 2.1a1 such that None now compares less than any other object. Code
1729 relying on this new behavior (like code that relied on the previous
1730 behavior) does so at its own risk.
1731
Barry Warsaw573b5412001-01-15 20:43:18 +00001732- Functions and methods now support getting and setting arbitrarily
1733 named attributes (PEP 232). Functions have a new __dict__
1734 (a.k.a. func_dict) which hold the function attributes. Methods get
1735 and set attributes on their underlying im_func. It is a TypeError
1736 to set an attribute on a bound method.
1737
Guido van Rossum051e3352001-01-15 19:11:10 +00001738- The xrange() object implementation has been improved so that
1739 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1740 limitation that in this case len(xrange(sys.maxint)) can't be
1741 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1742 work fine as long as the index i doesn't actually reach 2**31.
1743 (Python uses regular ints for sequence and string indices; fixing
1744 that is much more work.)
1745
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001746- Two changes to from...import:
1747
Guido van Rossumba381232001-02-03 15:06:40 +00001748 1) "from M import X" now works even if (after loading module M)
1749 sys.modules['M'] is not a real module; it's basically a getattr()
1750 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001751
1752 2) "from M import *" now looks for M.__all__ to decide which names to
1753 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1754 filters out names starting with '_' as before. Whether or not
1755 __all__ exists, there's no restriction on the type of M.
1756
Guido van Rossumf61f1662001-01-10 20:13:55 +00001757- File objects have a new method, xreadlines(). This is the fastest
1758 way to iterate over all lines in a file:
1759
1760 for line in file.xreadlines():
1761 ...do something to line...
1762
1763 See the xreadlines module (mentioned below) for how to do this for
1764 other file-like objects.
1765
1766- Even if you don't use file.xreadlines(), you may expect a speedup on
1767 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001768 quite a bit in platform-specific ways: on systems (like Linux) that
1769 support flockfile(), getc_unlocked(), and funlockfile(), those are
1770 used by default. On systems (like Windows) without getc_unlocked(),
1771 a complicated (but still thread-safe) method using fgets() is used by
1772 default.
1773
Tim Petersd52269b2001-01-25 06:23:18 +00001774 You can force use of the fgets() method by #define'ing
1775 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001776 getc_unlocked()).
1777
Tim Petersd52269b2001-01-25 06:23:18 +00001778 You can force fgets() not to be used by #define'ing
1779 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001780 test_bufio.py fails -- and let us know if it does!).
1781
1782- In addition, the fileinput module, while still slower than the other
1783 methods on most platforms, has been sped up too, by using
1784 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001785
1786- Support for run-time warnings has been added, including a new
1787 command line option (-W) to specify the disposition of warnings.
1788 See the description of the warnings module below.
1789
1790- Extensive changes have been made to the coercion code. This mostly
1791 affects extension modules (which can now implement mixed-type
1792 numerical operators without having to use coercion), but
1793 occasionally, in boundary cases the coercion semantics have changed
1794 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001795 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001796 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001797 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001798
Guido van Rossumf98eda02001-01-17 15:54:45 +00001799- In connection with the coercion changes, a new built-in singleton
1800 object, NotImplemented is defined. This can be returned for
1801 operations that wish to indicate they are not implemented for a
1802 particular combination of arguments. From C, this is
1803 Py_NotImplemented.
1804
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001805- The interpreter accepts now bytecode files on the command line even
1806 if they do not have a .pyc or .pyo extension. On Linux, after executing
1807
Martin v. Löwise214baa2001-02-04 22:37:56 +00001808import imp,sys,string
1809magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1810reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1811open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001812
1813 any byte code file can be used as an executable (i.e. as an argument
1814 to execve(2)).
1815
Tim Peters9940b802000-12-01 07:59:35 +00001816- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001817 character. In 1.6 and earlier, they never produced a sign,
1818 and raised an error if the value of the long was too large
1819 to fit in a Python int. In 2.0, they produced a sign if and
1820 only if too large to fit in an int. This was inconsistent
1821 across platforms (because the size of an int varies across
1822 platforms), and inconsistent with hex() and oct(). Example:
1823
1824 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001825 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001826 'ffffffbe' # in 2.0 and before, on 32-bit machines
1827 >>> hex(-0x42L)
1828 '-0x42L' # in all versions of Python
1829
Tim Peters9940b802000-12-01 07:59:35 +00001830 The behavior of %d formats for negative Python longs remains
1831 the same as in 2.0 (although in 1.6 and before, they raised
1832 an error if the long didn't fit in a Python int).
1833
1834 %u formats don't make sense for Python longs, but are allowed
1835 and treated the same as %d in 2.1. In 2.0, a negative long
1836 formatted via %u produced a sign if and only if too large to
1837 fit in an int. In 1.6 and earlier, a negative long formatted
1838 via %u raised an error if it was too big to fit in an int.
1839
Guido van Rossum3661d392000-12-12 22:10:31 +00001840- Dictionary objects have an odd new method, popitem(). This removes
1841 an arbitrary item from the dictionary and returns it (in the form of
1842 a (key, value) pair). This can be useful for algorithms that use a
1843 dictionary as a bag of "to do" items and repeatedly need to pick one
1844 item. Such algorithms normally end up running in quadratic time;
1845 using popitem() they can usually be made to run in linear time.
1846
Tim Peters36cdad12000-12-29 02:06:45 +00001847Standard library
1848
Thomas Woutersfe385252001-01-19 23:16:56 +00001849- In the time module, the time argument to the functions strftime,
1850 localtime, gmtime, asctime and ctime is now optional, defaulting to
1851 the current time (in the local timezone).
1852
Guido van Rossumda91f222001-01-15 16:36:08 +00001853- The ftplib module now defaults to passive mode, which is deemed a
1854 more useful default given that clients are often inside firewalls
1855 these days. Note that this could break if ftplib is used to connect
1856 to a *server* that is inside a firewall, from outside; this is
1857 expected to be a very rare situation. To fix that, you can call
1858 ftp.set_pasv(0).
1859
Martin v. Löwis10a27872001-01-13 09:54:41 +00001860- The module site now treats .pth files not only for path configuration,
1861 but also supports extensions to the initialization code: Lines starting
1862 with import are executed.
1863
Guido van Rossumf61f1662001-01-10 20:13:55 +00001864- There's a new module, warnings, which implements a mechanism for
1865 issuing and filtering warnings. There are some new built-in
1866 exceptions that serve as warning categories, and a new command line
1867 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1868 turns warnings into errors). warnings.warn(message[, category])
1869 issues a warning message; this can also be called from C as
1870 PyErr_Warn(category, message).
1871
1872- A new module xreadlines was added. This exports a single factory
1873 function, xreadlines(). The intention is that this code is the
1874 absolutely fastest way to iterate over all lines in an open
1875 file(-like) object:
1876
1877 import xreadlines
1878 for line in xreadlines.xreadlines(file):
1879 ...do something to line...
1880
1881 This is equivalent to the previous the speed record holder using
1882 file.readlines(sizehint). Note that if file is a real file object
1883 (as opposed to a file-like object), this is equivalent:
1884
1885 for line in file.xreadlines():
1886 ...do something to line...
1887
Tim Peters36cdad12000-12-29 02:06:45 +00001888- The bisect module has new functions bisect_left, insort_left,
1889 bisect_right and insort_right. The old names bisect and insort
1890 are now aliases for bisect_right and insort_right. XXX_right
1891 and XXX_left methods differ in what happens when the new element
1892 compares equal to one or more elements already in the list: the
1893 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001894 right. Code that doesn't care where equal elements end up should
1895 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001896
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001897- The new curses.panel module wraps the panel library that forms part
1898 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1899
Guido van Rossumf61f1662001-01-10 20:13:55 +00001900- The SocketServer module now sets the allow_reuse_address flag by
1901 default in the TCPServer class.
1902
1903- A new function, sys._getframe(), returns the stack frame pointer of
1904 the caller. This is intended only as a building block for
1905 higher-level mechanisms such as string interpolation.
1906
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001907- The pyexpat module supports a number of new handlers, which are
1908 available only in expat 1.2. If invocation of a callback fails, it
1909 will report an additional frame in the traceback. Parser objects
1910 participate now in garbage collection. If expat reports an unknown
1911 encoding, pyexpat will try to use a Python codec; that works only
1912 for single-byte charsets. The parser type objects is exposed as
1913 XMLParserObject.
1914
1915- xml.dom now offers standard definitions for symbolic node type and
1916 exception code constants, and a hierarchy of DOM exceptions. minidom
1917 was adjusted to use them.
1918
1919- The conformance of xml.dom.minidom to the DOM specification was
1920 improved. It detects a number of additional error cases; the
1921 previous/next relationship works even when the tree is modified;
1922 Node supports the normalize() method; NamedNodeMap, DocumentType and
1923 DOMImplementation classes were added; Element supports the
1924 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1925 method.
1926
Guido van Rossumf61f1662001-01-10 20:13:55 +00001927Build issues
1928
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001929- For Unix (and Unix-compatible) builds, configuration and building of
1930 extension modules is now greatly automated. Rather than having to
1931 edit the Modules/Setup file to indicate which modules should be
1932 built and where their include files and libraries are, a
1933 distutils-based setup.py script now takes care of building most
1934 extension modules. All extension modules built this way are built
1935 as shared libraries. Only a few modules that must be linked
1936 statically are still listed in the Setup file; you won't need to
1937 edit their configuration.
1938
1939- Python should now build out of the box on Cygwin. If it doesn't,
1940 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001941
1942- Python now always uses its own (renamed) implementation of getopt()
1943 -- there's too much variation among C library getopt()
1944 implementations.
1945
1946- C++ compilers are better supported; the CXX macro is always set to a
1947 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001948
Tim Petersd92dfe02000-12-12 01:18:41 +00001949Windows changes
1950
1951- select module: By default under Windows, a select() call
1952 can specify no more than 64 sockets. Python now boosts
1953 this Microsoft default to 512. If you need even more than
1954 that, see the MS docs (you'll need to #define FD_SETSIZE
1955 and recompile Python from source).
1956
Guido van Rossumf61f1662001-01-10 20:13:55 +00001957- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1958 subdirectory is no more!
1959
Tim Petersa3a3a032000-11-30 05:22:44 +00001960
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001961What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001962=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001963
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001964Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001965changes are in the file HISTORY. If you are making the jump directly
1966from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1967HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001968
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001969Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1970the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1971http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001972
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001973--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001974
1975======================================================================
1976
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001977What's new in 2.0 (since release candidate 1)?
1978==============================================
1979
1980Standard library
1981
1982- The copy_reg module was modified to clarify its intended use: to
1983 register pickle support for extension types, not for classes.
1984 pickle() will raise a TypeError if it is passed a class.
1985
1986- Fixed a bug in gettext's "normalize and expand" code that prevented
1987 it from finding an existing .mo file.
1988
1989- Restored support for HTTP/0.9 servers in httplib.
1990
Tim Peters989b7b92000-10-16 20:24:53 +00001991- The math module was changed to stop raising OverflowError in case of
1992 underflow, and return 0 instead in underflow cases. Whether Python
1993 used to raise OverflowError in case of underflow was platform-
1994 dependent (it did when the platform math library set errno to ERANGE
1995 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001996
1997- Fixed a bug in StringIO that occurred when the file position was not
1998 at the end of the file and write() was called with enough data to
1999 extend past the end of the file.
2000
2001- Fixed a bug that caused Tkinter error messages to get lost on
2002 Windows. The bug was fixed by replacing direct use of
2003 interp->result with Tcl_GetStringResult(interp).
2004
2005- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2006 redirect response.
2007
2008- Several changes were made to distutils: Some debugging code was
2009 removed from util. Fixed the installer used when an external zip
2010 program (like WinZip) is not found; the source code for this
2011 installer is in Misc/distutils. check_lib() was modified to behave
2012 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2013 test for whether installed modules are on sys.path was changed to
2014 use both normcase() and normpath().
2015
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002016- Several minor bugs were fixed in the xml package (the minidom,
2017 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002018
2019- The regression test driver (regrtest.py) behavior when invoked with
2020 -l changed: It now reports a count of objects that are recognized as
2021 garbage but not freed by the garbage collector.
2022
Tim Peters989b7b92000-10-16 20:24:53 +00002023- The regression test for the math module was changed to test
2024 exceptional behavior when the test is run in verbose mode. Python
2025 cannot yet guarantee consistent exception behavior across platforms,
2026 so the exception part of test_math is run only in verbose mode, and
2027 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002028
2029Internals
2030
2031- PyOS_CheckStack() has been disabled on Win64, where it caused
2032 test_sre to fail.
2033
2034Build issues
2035
2036- Changed compiler flags, so that gcc is always invoked with -Wall and
2037 -Wstrict-prototypes. Users compiling Python with GCC should see
2038 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002039 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002040 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002041
Tim Petersa3a3a032000-11-30 05:22:44 +00002042- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002043
2044Tools and other miscellany
2045
2046- The compiler in Tools/compiler was updated to support the new
2047 language features introduced in 2.0: extended print statement, list
2048 comprehensions, and augmented assignments. The new compiler should
2049 also be backwards compatible with Python 1.5.2; the compiler will
2050 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002051 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002052
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002053What's new in 2.0 release candidate 1 (since beta 2)?
2054=====================================================
2055
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002056What is release candidate 1?
2057
2058We believe that release candidate 1 will fix all known bugs that we
2059intend to fix for the 2.0 final release. This release should be a bit
2060more stable than the previous betas. We would like to see even more
2061widespread testing before the final release, so we are producing this
2062release candidate. The final release will be exactly the same unless
2063any show-stopping (or brown bag) bugs are found by testers of the
2064release candidate.
2065
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002066All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002067to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002068
2069Core language, builtins, and interpreter
2070
2071- A bug that caused crashes when __coerce__ was used with augmented
2072 assignment, e.g. +=, was fixed.
2073
2074- Raise ZeroDivisionError when raising zero to a negative number,
2075 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2076 power operator and the result of math.pow(0.0, -2.0) will vary by
2077 platform. On Linux, it raises a ValueError.
2078
2079- A bug in Unicode string interpolation was fixed that occasionally
2080 caused errors with formats including "%%". For example, the
2081 following expression "%% %s" % u"abc" no longer raises a TypeError.
2082
2083- Compilation of deeply nested expressions raises MemoryError instead
2084 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2085
2086- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2087 rendering them useless. They are now written in binary mode again.
2088
2089Standard library
2090
2091- Keyword arguments are now accepted for most pattern and match object
2092 methods in SRE, the standard regular expression engine.
2093
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002094- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002095 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002096
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002097- Several bugs in the Unicode handling and error handling in _tkinter
2098 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002099
2100- Fix memory management errors in Merge() and Tkapp_Call() routines.
2101
2102- Several changes were made to cStringIO to make it compatible with
2103 the file-like object interface and with StringIO. If operations are
2104 performed on a closed object, an exception is raised. The truncate
2105 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002106 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002107
2108- There were many changes made to the linuxaudiodev module and its
2109 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002110 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002111
2112 Note that this module is named poorly, because it should work
2113 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002114 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002115
2116 The module now raises exceptions when errors occur instead of
2117 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2118 audio) and defines a getptr() method that calls the
2119 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2120
2121- The library_version attribute, introduced in an earlier beta, was
2122 removed because it can not be supported with early versions of the C
2123 readline library, which provides no way to determine the version at
2124 compile-time.
2125
2126- The binascii module is now enabled on Win64.
2127
Tim Peters46446d62000-10-09 21:19:31 +00002128- tokenize.py no longer suffers "recursion depth" errors when parsing
2129 programs with very long string literals.
2130
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002131Internals
2132
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002133- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002134 which is called when the interpreter starts up to determine where
2135 the standard library is installed. These vulnerabilities affect all
2136 previous versions of Python and can be exploited by setting very
2137 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2138 setuid Python script, although use of the wrapper in
2139 Misc/setuid-prog.c will eliminate the vulnerability.
2140
2141- Fixed garbage collection bugs in instance creation that were
2142 triggered when errors occurred during initialization. The solution,
2143 applied in cPickle and in PyInstance_New(), is to call
2144 PyObject_GC_Init() after the initialization of the object's
2145 container attributes is complete.
2146
2147- pyexpat adds definitions of PyModule_AddStringConstant and
2148 PyModule_AddObject if the Python version is less than 2.0, which
2149 provides compatibility with PyXML on Python 1.5.2.
2150
2151- If the platform has a bogus definition for LONG_BIT (the number of
2152 bits in a long), an error will be reported at compile time.
2153
2154- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2155 collection crashes and possibly other, unreported crashes.
2156
2157- Fixed a memory leak in _PyUnicode_Fini().
2158
2159Build issues
2160
2161- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002162 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002163 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002164
2165- The mmap.PAGESIZE constant is now initialized using sysconf when
2166 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2167
2168- The md5 file should now compile on all platforms.
2169
2170- The select module now compiles on platforms that do not define
2171 POLLRDNORM and related constants.
2172
2173- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002174 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002175
Jeremy Hylton10921202000-10-09 18:34:12 +00002176- BeOS: A number of changes were made to the build and installation
2177 process. ar-fake now operates on a directory of object files.
2178 dl_export.h is gone, and its macros now appear on the mwcc command
2179 line during build on PPC BeOS.
2180
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002181- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002182 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002183
2184- Cygwin: Support for shared libraries, Tkinter, and sockets.
2185
2186- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2187
2188Tools and other miscellany
2189
2190- Removed debugging prints from main used with freeze.
2191
Tim Peters46446d62000-10-09 21:19:31 +00002192- IDLE auto-indent no longer crashes when it encounters Unicode
2193 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002194
2195What's new in 2.0 beta 2 (since beta 1)?
2196========================================
2197
2198Core language, builtins, and interpreter
2199
Tim Peters482c0212000-09-26 06:33:09 +00002200- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002201 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002202
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002203- Add -h and -V command line options to print the usage message and
2204 Python version number and exit immediately.
2205
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002206- eval() and exec accept Unicode objects as code parameters.
2207
2208- getattr() and setattr() now also accept Unicode objects for the
2209 attribute name, which are converted to strings using the default
2210 encoding before lookup.
2211
2212- Multiplication on string and Unicode now does proper bounds
2213 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2214 string is too long."
2215
2216- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002217 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002218
Jeremy Hylton1b618592000-09-26 05:32:36 +00002219
2220Standard library and extensions
2221
Guido van Rossum5b08f132001-04-16 02:05:23 +00002222- socket module: the OpenSSL code now adds support for RAND_status()
2223 and EGD (Entropy Gathering Device).
2224
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002225- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002226 argument checking; it still takes no arguments.
2227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002228- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002229
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002230- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002231
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002232- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002233
2234- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002235 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002236
2237- copy: Copy Unicode objects atomically.
2238
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002239- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002240
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002241- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002242
Fred Drake67233bc2000-09-26 16:40:27 +00002243- dbm: Add get() and setdefault() methods to dbm object. Add constant
2244 `library' to module that names the library used. Added doc strings
2245 and method names to error messages. Uses configure to determine
2246 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2247 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002248
2249- distutils: Update to version 0.9.3.
2250
2251- dl: Add several dl.RTLD_ constants.
2252
2253- fpectl: Now supported on FreeBSD.
2254
2255- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2256 found by the collector will be saved in gc.garbage. This is useful
2257 for debugging a program that creates reference cycles.
2258
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002259- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002260 of HTTP class. Do not close socket on zero-length response. Do not
2261 crash when server sends invalid content-length header.
2262
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002263- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002264
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002265- marshal: When reading a short, sign-extend on platforms where shorts
2266 are bigger than 16 bits. When reading a long, repair the unportable
2267 sign extension that was being done for 64-bit machines. (It assumed
2268 that signed right shift sign-extends.)
2269
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002270- operator: Add contains(), invert(), __invert__() as aliases for
2271 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002272
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002273- os: Add support for popen2() and popen3() on all platforms where
2274 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002275
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002276- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002277 clicking on a file in Explorer (or passing the file name to the
2278 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002279
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002280- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002281 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002282
2283- pickle: Now raises ValueError when an invalid pickle that contains
2284 a non-string repr where a string repr was expected. This behavior
2285 matches cPickle.
2286
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002287- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002288
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002289- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002290
2291- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002292 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002293 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002294
2295- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002296 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002297
2298- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002299 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002300 few cycles during startup since the first call to
2301 setdefaultencoding() will initialize the codec registry and the
2302 encodings package.
2303
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002304- socket: Support for size hint in readlines() method of object returned
2305 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002306
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002307- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002308 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002309 is followed by whitespace.
2310
Tim Petersa3a3a032000-11-30 05:22:44 +00002311- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002312
2313- struct: Check ranges for bytes and shorts.
2314
2315- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002316 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002317
2318- Tkinter: Image objects are now guaranteed to have unique ids. Set
2319 event.delta to zero if Tk version doesn't support mousewheel.
2320 Removed some debugging prints.
2321
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002322- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002323
Fred Drake67233bc2000-09-26 16:40:27 +00002324- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002325 which works around a bug in Norton AntiVirus 2000 that leads directly
2326 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002327
2328- xml: New version detection code allows PyXML to override standard
2329 XML package if PyXML version is greater than 0.6.1.
2330
Fred Drake64bb3802000-09-26 16:21:35 +00002331- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2332 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2333 tree only for nodes which are sufficiently interesting to a specific
2334 application. Does not provide the HTML-specific extensions. Still
2335 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002336
Fred Drake64bb3802000-09-26 16:21:35 +00002337- xml.sax: SAX 2 support for Python, including all the handler
2338 interfaces needed to process XML 1.0 compliant XML. Some
2339 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002340
Fred Drake64bb3802000-09-26 16:21:35 +00002341- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2342 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002343
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002344
Jeremy Hylton1b618592000-09-26 05:32:36 +00002345C API
2346
2347- Add three new convenience functions for module initialization --
2348 PyModule_AddObject(), PyModule_AddIntConstant(), and
2349 PyModule_AddStringConstant().
2350
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002351- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002352 removed and add #error to Python.h if NULL isn't defined after
2353 #include of stdio.h.
2354
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002355- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002356 backwards compatibility (at the source level) with old extensions.
2357
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002358- A wrapper API was added for signal() and sigaction(). Instead of
2359 either function, always use PyOS_getsig() to get a signal handler
2360 and PyOS_setsig() to set one. A new convenience typedef
2361 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002362
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002363- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002364 internal data buffer and size of a string object -- or the default
2365 encoded version of a Unicode object.
2366
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002367- PyString_Size() and PyString_AsString() accept Unicode objects.
2368
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002369- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002370 exists). INT_MAX and LONG_MAX will always be defined, even if
2371 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002372
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002373- PyFloat_FromString takes a second argument, pend, that was
2374 effectively useless. It is now officially useless but preserved for
2375 backwards compatibility. If the pend argument is not NULL, *pend is
2376 set to NULL.
2377
2378- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2379 for the attribute name. See note on getattr() above.
2380
2381- A few bug fixes to argument processing for Unicode.
2382 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2383 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2384 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002385 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002386
2387- Py_BuildValue accepts B format (for bgen-generated code).
2388
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002389
Jeremy Hylton1b618592000-09-26 05:32:36 +00002390Internals
2391
2392- On Unix, fix code for finding Python installation directory so that
2393 it works when argv[0] is a relative path.
2394
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002395- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002396 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002397 rather than by generating a copy of the object.
2398
Tim Peters482c0212000-09-26 06:33:09 +00002399- Several of the internal Unicode tables are much smaller now, and
2400 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002401
Jeremy Hylton97693b02000-09-26 17:42:51 +00002402- In the garbage collector: Fixed bug in collection of tuples. Fixed
2403 bug that caused some instances to be removed from the container set
2404 while they were still live. Fixed parsing in gc.set_debug() for
2405 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002406
2407- Fixed refcount problem in instance deallocation that only occurred
2408 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2409
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002410- On Windows, getpythonregpath is now protected against null data in
2411 registry key.
2412
2413- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002414 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002415
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002416
Jeremy Hylton1b618592000-09-26 05:32:36 +00002417Build and platform-specific issues
2418
2419- Better support of GNU Pth via --with-pth configure option.
2420
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002421- Python/C API now properly exposed to dynamically-loaded extension
2422 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002423
2424- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2425 Don't define MS_SYNC to be zero when it is undefined. Added missing
2426 prototypes in posixmodule.c.
2427
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002428- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002429 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002430
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002431- Fix largefile support on older NetBSD systems and OpenBSD by adding
2432 define for TELL64.
2433
2434
2435Tools and other miscellany
2436
2437- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2438
2439- freeze: The modulefinder now works with 2.0 opcodes.
2440
Tim Petersa3a3a032000-11-30 05:22:44 +00002441- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002442 Move hackery of sys.argv until after the Tk instance has been
2443 created, which allows the application-specific Tkinter
2444 initialization to be executed if present; also pass an explicit
2445 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002446
Jeremy Hylton1b618592000-09-26 05:32:36 +00002447
2448What's new in 2.0 beta 1?
2449=========================
2450
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002451Source Incompatibilities
2452------------------------
2453
2454None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2455such as single-argument append(), connect() and bind(), and changes to
2456str(long) and repr(float).
2457
2458
2459Binary Incompatibilities
2460------------------------
2461
2462- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2463with Python 2.0; these extensions will have to be rebuilt for Python
24642.0.
2465
2466- On Windows, attempting to import a third party extension built for
2467Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2468can do about this. Check your PYTHONPATH environment variable!
2469
2470- Python bytecode files (*.pyc and *.pyo) are not compatible between
2471releases.
2472
2473
2474Overview of Changes Since 1.6
2475-----------------------------
2476
2477There are many new modules (including brand new XML support through
2478the xml package, and i18n support through the gettext module); a list
2479of all new modules is included below. Lots of bugs have been fixed.
2480
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002481The process for making major new changes to the language has changed
2482since Python 1.6. Enhancements must now be documented by a Python
2483Enhancement Proposal (PEP) before they can be accepted.
2484
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002485There are several important syntax enhancements, described in more
2486detail below:
2487
2488 - Augmented assignment, e.g. x += 1
2489
2490 - List comprehensions, e.g. [x**2 for x in range(10)]
2491
2492 - Extended import statement, e.g. import Module as Name
2493
2494 - Extended print statement, e.g. print >> file, "Hello"
2495
2496Other important changes:
2497
2498 - Optional collection of cyclical garbage
2499
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002500Python Enhancement Proposal (PEP)
2501---------------------------------
2502
2503PEP stands for Python Enhancement Proposal. A PEP is a design
2504document providing information to the Python community, or describing
2505a new feature for Python. The PEP should provide a concise technical
2506specification of the feature and a rationale for the feature.
2507
2508We intend PEPs to be the primary mechanisms for proposing new
2509features, for collecting community input on an issue, and for
2510documenting the design decisions that have gone into Python. The PEP
2511author is responsible for building consensus within the community and
2512documenting dissenting opinions.
2513
2514The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002515
2516Augmented Assignment
2517--------------------
2518
2519This must have been the most-requested feature of the past years!
2520Eleven new assignment operators were added:
2521
Guido van Rossume905e952000-09-05 12:42:46 +00002522 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002523
2524For example,
2525
2526 A += B
2527
2528is similar to
2529
2530 A = A + B
2531
2532except that A is evaluated only once (relevant when A is something
2533like dict[index].attr).
2534
2535However, if A is a mutable object, A may be modified in place. Thus,
2536if A is a number or a string, A += B has the same effect as A = A+B
2537(except A is only evaluated once); but if a is a list, A += B has the
2538same effect as A.extend(B)!
2539
2540Classes and built-in object types can override the new operators in
2541order to implement the in-place behavior; the not-in-place behavior is
2542used automatically as a fallback when an object doesn't implement the
2543in-place behavior. For classes, the method name is derived from the
2544method name for the corresponding not-in-place operator by inserting
2545an 'i' in front of the name, e.g. __iadd__ implements in-place
2546__add__.
2547
2548Augmented assignment was implemented by Thomas Wouters.
2549
2550
2551List Comprehensions
2552-------------------
2553
2554This is a flexible new notation for lists whose elements are computed
2555from another list (or lists). The simplest form is:
2556
2557 [<expression> for <variable> in <sequence>]
2558
Guido van Rossum56db0952000-09-06 23:34:25 +00002559For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002560This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002561
2562You can also add a condition:
2563
2564 [<expression> for <variable> in <sequence> if <condition>]
2565
2566For example, [w for w in words if w == w.lower()] would yield the list
2567of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002568than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002569
2570You can also have nested for loops and more than one 'if' clause. For
2571example, here's a function that flattens a sequence of sequences::
2572
2573 def flatten(seq):
2574 return [x for subseq in seq for x in subseq]
2575
2576 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2577
2578This prints
2579
2580 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2581
2582List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002583Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002584
2585
2586Extended Import Statement
2587-------------------------
2588
2589Many people have asked for a way to import a module under a different
2590name. This can be accomplished like this:
2591
2592 import foo
2593 bar = foo
2594 del foo
2595
2596but this common idiom gets old quickly. A simple extension of the
2597import statement now allows this to be written as follows:
2598
2599 import foo as bar
2600
2601There's also a variant for 'from ... import':
2602
2603 from foo import bar as spam
2604
2605This also works with packages; e.g. you can write this:
2606
2607 import test.regrtest as regrtest
2608
2609Note that 'as' is not a new keyword -- it is recognized only in this
2610context (this is only possible because the syntax for the import
2611statement doesn't involve expressions).
2612
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002613Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002614
2615
2616Extended Print Statement
2617------------------------
2618
2619Easily the most controversial new feature, this extension to the print
2620statement adds an option to make the output go to a different file
2621than the default sys.stdout.
2622
2623For example, to write an error message to sys.stderr, you can now
2624write:
2625
2626 print >> sys.stderr, "Error: bad dog!"
2627
2628As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002629evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002630
2631 print >> None, "Hello world"
2632
2633is equivalent to
2634
2635 print "Hello world"
2636
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002637Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002638
2639
2640Optional Collection of Cyclical Garbage
2641---------------------------------------
2642
2643Python is now equipped with a garbage collector that can hunt down
2644cyclical references between Python objects. It's no replacement for
2645reference counting; in fact, it depends on the reference counts being
2646correct, and decides that a set of objects belong to a cycle if all
2647their reference counts can be accounted for from their references to
2648each other. This devious scheme was first proposed by Eric Tiedemann,
2649and brought to implementation by Neil Schemenauer.
2650
2651There's a module "gc" that lets you control some parameters of the
2652garbage collection. There's also an option to the configure script
2653that lets you enable or disable the garbage collection. In 2.0b1,
2654it's on by default, so that we (hopefully) can collect decent user
2655experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002656performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002657off by default in the final 2.0 release.
2658
2659
2660Smaller Changes
2661---------------
2662
2663A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2664map(None, seq1, seq2, ...) when the sequences have the same length;
2665i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2666the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002667zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002668
2669sys.version_info is a tuple (major, minor, micro, level, serial).
2670
2671Dictionaries have an odd new method, setdefault(key, default).
2672dict.setdefault(key, default) returns dict[key] if it exists; if not,
2673it sets dict[key] to default and returns that value. Thus:
2674
2675 dict.setdefault(key, []).append(item)
2676
2677does the same work as this common idiom:
2678
2679 if not dict.has_key(key):
2680 dict[key] = []
2681 dict[key].append(item)
2682
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002683There are two new variants of SyntaxError that are raised for
2684indentation-related errors: IndentationError and TabError.
2685
2686Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2687escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002688
2689The limits on the size of expressions and file in Python source code
2690have been raised from 2**16 to 2**32. Previous versions of Python
2691were limited because the maximum argument size the Python VM accepted
2692was 2**16. This limited the size of object constructor expressions,
2693e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2694limit was raised thanks to a patch by Charles Waldman that effectively
2695fixes the problem. It is now much more likely that you will be
2696limited by available memory than by an arbitrary limit in Python.
2697
2698The interpreter's maximum recursion depth can be modified by Python
2699programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2700limit is the maximum number of recursive calls that can be made by
2701Python code. The limit exists to prevent infinite recursion from
2702overflowing the C stack and causing a core dump. The default value is
27031000. The maximum safe value for a particular platform can be found
2704by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002705
2706New Modules and Packages
2707------------------------
2708
2709atexit - for registering functions to be called when Python exits.
2710
2711imputil - Greg Stein's alternative API for writing custom import
2712hooks.
2713
2714pyexpat - an interface to the Expat XML parser, contributed by Paul
2715Prescod.
2716
2717xml - a new package with XML support code organized (so far) in three
2718subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2719would fill a volume. There's a special feature whereby a
2720user-installed package named _xmlplus overrides the standard
2721xmlpackage; this is intended to give the XML SIG a hook to distribute
2722backwards-compatible updates to the standard xml package.
2723
2724webbrowser - a platform-independent API to launch a web browser.
2725
2726
Guido van Rossume905e952000-09-05 12:42:46 +00002727Changed Modules
2728---------------
2729
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002730array -- new methods for array objects: count, extend, index, pop, and
2731remove
2732
2733binascii -- new functions b2a_hex and a2b_hex that convert between
2734binary data and its hex representation
2735
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002736calendar -- Many new functions that support features including control
2737over which day of the week is the first day, returning strings instead
2738of printing them. Also new symbolic constants for days of week,
2739e.g. MONDAY, ..., SUNDAY.
2740
2741cgi -- FieldStorage objects have a getvalue method that works like a
2742dictionary's get method and returns the value attribute of the object.
2743
2744ConfigParser -- The parser object has new methods has_option,
2745remove_section, remove_option, set, and write. They allow the module
2746to be used for writing config files as well as reading them.
2747
2748ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002749optionally support the RFC 959 REST command.
2750
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002751gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002752
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002753httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2754the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002755
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002756locale -- implement getdefaultlocale for Win32 and Macintosh
2757
2758marshal -- no longer dumps core when marshaling deeply nested or
2759recursive data structures
2760
2761os -- new functions isatty, seteuid, setegid, setreuid, setregid
2762
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002763os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2764support under Unix.
2765
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002766os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002767
2768os.path -- fix semantics of os.path.commonprefix
2769
2770smtplib -- support for sending very long messages
2771
2772socket -- new function getfqdn()
2773
2774readline -- new functions to read, write and truncate history files.
2775The readline section of the library reference manual contains an
2776example.
2777
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002778select -- add interface to poll system call
2779
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002780shutil -- new copyfileobj function
2781
2782SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2783HTTP server.
2784
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002785Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002786
2787urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002788e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002789
2790whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002791
2792
2793Obsolete Modules
2794----------------
2795
2796None. However note that 1.6 made a whole slew of modules obsolete:
2797stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2798poly, zmod, strop, util, whatsound.
2799
2800
2801Changed, New, Obsolete Tools
2802----------------------------
2803
Tim Peters8b092332000-09-05 20:15:25 +00002804None.
Guido van Rossume905e952000-09-05 12:42:46 +00002805
2806
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002807C-level Changes
2808---------------
2809
2810Several cleanup jobs were carried out throughout the source code.
2811
2812All C code was converted to ANSI C; we got rid of all uses of the
2813Py_PROTO() macro, which makes the header files a lot more readable.
2814
2815Most of the portability hacks were moved to a new header file,
2816pyport.h; several other new header files were added and some old
2817header files were removed, in an attempt to create a more rational set
2818of header files. (Few of these ever need to be included explicitly;
2819they are all included by Python.h.)
2820
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002821Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002822and Win64, especially for the new Intel Itanium processor. Mick also
2823added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002824
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002825The C APIs to return an object's size have been update to consistently
2826use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2827previous versions, the abstract interfaces used PyXXX_Length and the
2828concrete interfaces used PyXXX_Size. The old names,
2829e.g. PyObject_Length, are still available for backwards compatibility
2830at the API level, but are deprecated.
2831
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002832The PyOS_CheckStack function has been implemented on Windows by
2833Fredrik Lundh. It prevents Python from failing with a stack overflow
2834on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002835
2836The GC changes resulted in creation of two new slots on object,
2837tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002838the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002839
2840The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002841C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002842
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002843PyErr_Format has been updated to automatically calculate the size of
2844the buffer needed to hold the formatted result string. This change
2845prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002846
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002847New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002848
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002849PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2850that are the same as their non-Ex counterparts except they take an
2851extra flag argument that tells them to close the file when done.
2852
2853XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002854
Tim Peters8b092332000-09-05 20:15:25 +00002855
2856Windows Changes
2857---------------
2858
2859New popen2/popen3/peopen4 in os module (see Changed Modules above).
2860
2861os.popen is much more usable on Windows 95 and 98. See Microsoft
2862Knowledge Base article Q150956. The Win9x workaround described there
2863is implemented by the new w9xpopen.exe helper in the root of your
2864Python installation. Note that Python uses this internally; it is not
2865a standalone program.
2866
2867Administrator privileges are no longer required to install Python
2868on Windows NT or Windows 2000. If you have administrator privileges,
2869Python's registry info will be written under HKEY_LOCAL_MACHINE.
2870Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002871under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002872uses of Python, but will prevent some advanced uses from working
2873(for example, running a Python script as an NT service, or possibly
2874from CGI).
2875
2876[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2877installer; instead, it installs the needed Tcl/Tk files directly in the
2878Python directory. If you already have a Tcl/Tk installation, this
2879wastes some disk space (about 4 Megs) but avoids problems with
2880conflicting Tcl/Tk installations, and makes it much easier for Python
2881to ensure that Tcl/Tk can find all its files.
2882
2883[This was new in 1.6] The Windows installer now installs by default in
2884\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2885
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002886
2887Updates to the changes between 1.5.2 and 1.6
2888--------------------------------------------
2889
2890The 1.6 NEWS file can't be changed after the release is done, so here
2891is some late-breaking news:
2892
2893New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2894and changes to getlocale() and setlocale().
2895
2896The new module is now enabled per default.
2897
2898It is not true that the encodings codecs cannot be used for normal
2899strings: the string.encode() (which is also present on 8-bit strings
2900!) allows using them for 8-bit strings too, e.g. to convert files from
2901cp1252 (Windows) to latin-1 or vice-versa.
2902
2903Japanese codecs are available from Tamito KAJIYAMA:
2904http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2905
2906
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002907======================================================================