blob: 1d86a4313ea343d496bfa3aefa8ce0e2adee519f [file] [log] [blame]
Tim Petersabf925f2001-09-28 21:53:42 +00001What's New in Python 2.2b1?
2Release date: 28-Sep-2100
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum687ae002001-10-15 22:03:32 +00007- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00008 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00009 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +000010 remains: the __dict__ of a new-style class is a read-only proxy; you
11 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +000012 __defined__ attribute of new-style types no longer exists, for lack
13 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +000014 future a __cache__ may be resurrected with a similar function, if I
15 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +000016
Tim Peters1c9ca872001-10-04 06:43:12 +000017- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
18 always returned None, even when there was a class docstring).
19
20- doctest now finds and runs docstrings attached to new-style classes,
21 class methods, static methods, and properties.
22
Tim Petersabf925f2001-09-28 21:53:42 +000023Core
24
Guido van Rossuma8bcf802001-10-15 15:53:58 +000025- A very subtle syntactical pitfall in list comprehensions was fixed.
26 For example: [a+b for a in 'abc', for b in 'def']. The comma in
27 this example is a mistake. Previously, this would silently let 'a'
28 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
29 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
30 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
31 Note that [a for a in <singleton>] is a convoluted way to say
32 [<singleton>] anyway, so it's not like any expressiveness is lost.
33
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000034- binascii has now two quopri support functions, a2b_qp and b2a_qp.
35
Martin v. Löwis0daad592001-09-30 21:09:59 +000036- readline now supports setting the startup_hook and the pre_event_hook.
37
Martin v. Löwis16628c92001-10-04 22:46:41 +000038- posix supports chroot where available.
39
Tim Petersabf925f2001-09-28 21:53:42 +000040Library
41
Guido van Rossum3c288632001-10-16 21:13:49 +000042- thread.start_new_thread() now returns the thread ID (previously None).
43
Tim Peters7402f792001-10-02 03:53:41 +000044- doctest now excludes functions and classes not defined by the module
45 being tested, thanks to Tim Hochberg.
46
Guido van Rossumc4b09b42001-10-04 10:19:00 +000047- profile now produces correct output in situations where an exception
48 raised in Python is cleared by C code (e.g. hasattr()). This used
49 to cause wrong output, including spurious claims of recursive
50 functions and attribution of time spent to the wrong function.
51
Tim Peters0a1fc4e2001-10-07 03:12:08 +000052 The code and documentation for the derived OldProfile and HotProfile
53 profiling classes was removed. The code hasn't worked for years (if
54 you tried to use them, they raised exceptions). OldProfile
55 intended to reproduce the behavior of the profiler Python used more
56 than 7 years ago, and isn't interesting anymore. HotProfile intended
57 to provide a faster profiler (but producing less information), and
58 that's a worthy goal we intend to meet via a different approach (but
59 without losing information).
60
Tim Peterscce092d2001-10-09 05:31:56 +000061- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000062 a much better system-specific calibration constant. The constant can
63 now be specified in an instance constructor, or as a Profile class or
64 instance variable, instead of by editing profile.py's source code.
65 Calibration must still be done manually (see the docs for the profile
66 module).
67
68 Note that Profile.calibrate() must be overriden by subclasses.
69 Improving the accuracy required exploiting detailed knowledge of
70 profiler internals; the earlier method abstracted away the details
71 and measured a simplified model instead, but consequently computed
72 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000073
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000074- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +000075 which indicates whether output is intended for the header 'Q'
76 encoding.
77
78- Decompression objects in the zlib module now accept an optional
79 second parameter to decompress() that specifies the maximum amount
80 of memory to use for the uncompressed data.
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000081
Guido van Rossumed554f62001-10-02 23:15:37 +000082Tools/Demos
83
84- Demo/dns was removed. It no longer serves any purpose; a package
85 derived from it is now maintained by Anthony Baxter, see
86 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000087
88Build
89
90C API
91
Tim Petersd38b1c72001-09-30 05:09:37 +000092- PyLong_AsLongLong() now accepts int (as well as long) arguments.
93 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
94 as long) arguments.
95
Guido van Rossum3c288632001-10-16 21:13:49 +000096- PyThread_start_new_thread() now returns a long int giving the thread
97 ID, if one can be calculated; it returns -1 for error, 0 if no
98 thread ID is calculated (this is an incompatible change, but only
99 the thread module used this API). This code has only really been
100 tested on Linux and Windows; other platforms please beware (and
101 report any bugs or strange behavior).
102
Tim Petersabf925f2001-09-28 21:53:42 +0000103New platforms
104
105Tests
106
107Windows
108
Tim Peters04cf1d32001-10-09 22:39:40 +0000109- Installer: If you install IDLE, and don't disable file-extension
110 registration, a new "Edit with IDLE" context (right-click) menu entry
111 is created for .py and .pyw files.
112
Tim Peters1ce3cf72001-10-01 17:58:40 +0000113- The signal module now supports SIGBREAK on Windows, thanks to Steven
114 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
115 action remains to call Win32 ExitProcess(). This can be changed via
116 signal.signal(). For example:
117
118 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
119 # (SIGINT) behavior.
120 import signal
121 signal.signal(signal.SIGBREAK,
122 signal.default_int_handler)
123
124 try:
125 while 1:
126 pass
127 except KeyboardInterrupt:
128 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
129 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
130 # program without the possibility for any Python-level cleanup).
131 print "Clean exit"
132
Tim Petersabf925f2001-09-28 21:53:42 +0000133
Tim Petersb07352e2001-09-08 01:25:47 +0000134What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000135Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000136===========================
137
Guido van Rossum808eea72001-09-25 04:15:41 +0000138Type/class unification and new-style classes
139
140- pydoc and inspect are now aware of new-style classes;
141 e.g. help(list) at the interactive prompt now shows proper
142 documentation for all operations on list objects.
143
144- Applications using Jim Fulton's ExtensionClass module can now safely
145 be used with Python 2.2. In particular, Zope 2.4.1 now works with
146 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
147 examples also work again. It is hoped that Gtk and Boost also work
148 with 2.2a4 and beyond. (If you can confirm this, please write
149 webmaster@python.org; if there are still problems, please open a bug
150 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000151
Tim Peters66c1a522001-09-24 21:17:50 +0000152- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
153 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
154 in the constructed property object. fget, fset and fdel weren't
155 discoverable from Python in 2.2a3. __doc__ is new, and allows to
156 associate a docstring with a property.
157
Guido van Rossum808eea72001-09-25 04:15:41 +0000158- Comparison overloading is now more completely implemented. For
159 example, a str subclass instance can properly be compared to a str
160 instance, and it can properly overload comparison. Ditto for most
161 other built-in object types.
162
163- The repr() of new-style classes has changed; instead of <type
164 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
165 *except* for built-in types, which are still rendered as <type
166 'Foo'> (to avoid upsetting existing code that might parse or
167 otherwise rely on repr() of certain type objects).
168
169- The repr() of new-style objects is now always <Foo object at XXX>;
170 previously, it was sometimes <Foo instance at XXX>.
171
172- For new-style classes, what was previously called __getattr__ is now
173 called __getattribute__. This method, if defined, is called for
174 *every* attribute access. A new __getattr__ hook mor similar to the
175 one in classic classes is defined which is called only if regular
176 attribute access raises AttributeError; to catch *all* attribute
177 access, you can use __getattribute__ (for new-style classes). If
178 both are defined, __getattribute__ is called first, and if it raises
179 AttributeError, __getattr__ is called.
180
181- The __class__ attribute of new-style objects can be assigned to.
182 The new class must have the same C-level object layout as the old
183 class.
184
185- The builtin file type can be subclassed now. In the usual pattern,
186 "file" is the name of the builtin type, and file() is a new builtin
187 constructor, with the same signature as the builtin open() function.
188 file() is now the preferred way to open a file.
189
190- Previously, __new__ would only see sequential arguments passed to
191 the type in a constructor call; __init__ would see both sequential
192 and keyword arguments. This made no sense whatsoever any more, so
193 now both __new__ and __init__ see all arguments.
194
195- Previously, hash() applied to an instance of a subclass of str or
196 unicode always returned 0. This has been repaired.
197
198- Previously, an operation on an instance of a subclass of an
199 immutable type (int, long, float, complex, tuple, str, unicode),
200 where the subtype didn't override the operation (and so the
201 operation was handled by the builtin type), could return that
202 instance instead a value of the base type. For example, if s was of
203 a str sublass type, s[:] returned s as-is. Now it returns a str
204 with the same value as s.
205
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000206- Provisional support for pickling new-style objects has been added.
207
Guido van Rossum808eea72001-09-25 04:15:41 +0000208Core
209
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000210- file.writelines() now accepts any iterable object producing strings.
211
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000212- PyUnicode_FromEncodedObject() now works very much like
213 PyObject_Str(obj) in that it tries to use __str__/tp_str
214 on the object if the object is not a string or buffer. This
215 makes unicode() behave like str() when applied to non-string/buffer
216 objects.
217
Martin v. Löwis2777c022001-09-19 13:47:32 +0000218- PyFile_WriteObject now passes Unicode object to the file's write
219 method. As a result, all file-like object which may be the target
220 of a print statement must support Unicode objects, i.e. they must
221 at least convert them into ASCII strings.
222
Guido van Rossum624c8af2001-09-18 15:21:04 +0000223- Thread scheduling on Solaris should be improved; it is no longer
224 necessary to insert a small sleep at the start of a thread in order
225 to let other runnable threads be scheduled.
226
Tim Petersb07352e2001-09-08 01:25:47 +0000227Library
228
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000229- StringIO.StringIO instances and cStringIO.StringIO instances support
230 read character buffer compatible objects for their .write() methods.
231 These objects are converted to strings and then handled as such
232 by the instances.
233
Barry Warsaw2f600732001-09-24 04:28:10 +0000234- The "email" package has been added. This is basically a port of the
235 mimelib package <http://sf.net/projects/mimelib> with API changes
236 and some implementations updated to use iterators and generators.
237
Tim Peters8a9c2842001-09-22 21:30:22 +0000238- difflib.ndiff() and difflib.Differ.compare() are generators now. This
239 restores the ability of Tools/scripts/ndiff.py to start producing output
240 before the entire comparison is complete.
241
Barry Warsaw58b072d2001-09-22 04:44:21 +0000242- StringIO.StringIO instances and cStringIO.StringIO instances support
243 iteration just like file objects (i.e. their .readline() method is
244 called for each iteration until it returns an empty string).
245
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000246- The codecs module has grown four new helper APIs to access
247 builtin codecs: getencoder(), getdecoder(), getreader(),
248 getwriter().
249
Guido van Rossum624c8af2001-09-18 15:21:04 +0000250- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
251 simplifies writing XML RPC servers.
252
Barry Warsaw647d5e82001-09-28 17:01:02 +0000253- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000254 after interpretation of symbolic links. On non-Unix systems, this
255 is an alias for os.path.abspath().
256
Tim Peters16a77ad2001-09-08 04:00:12 +0000257- operator.indexOf() (PySequence_Index() in the C API) now works with any
258 iterable object.
259
Guido van Rossum624c8af2001-09-18 15:21:04 +0000260- smtplib now supports various authentication and security features of
261 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000262
Guido van Rossum624c8af2001-09-18 15:21:04 +0000263- hmac: a new module implementing keyed hashing for message
264 authentication.
265
266- mimetypes now recognizes more extensions and file types. At the
267 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000268
Guido van Rossum624c8af2001-09-18 15:21:04 +0000269- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000270 Python 2.2 bytecode generation. It has also been promoted from a
271 Tool to a standard library package. (Tools/compiler still exists as
272 a sample driver.)
273
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000274Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000275
Tim Petersb07352e2001-09-08 01:25:47 +0000276Build
277
Guido van Rossum624c8af2001-09-18 15:21:04 +0000278- Large file support (LFS) is now automatic when the platform supports
279 it; no more manual configuration tweaks are needed. On Linux, at
280 least, it's possible to have a system whose C library supports large
281 files but whose kernel doesn't; in this case, large file support is
282 still enabled but doesn't do you any good unless you upgrade your
283 kernel or share your Python executable with another system whose
284 kernel has large file support.
285
286- The configure script now supplies plausible defaults in a
287 cross-compilation environment. This doesn't mean that the supplied
288 values are always correct, or that cross-compilation now works
289 flawlessly -- but it's a first step (and it shuts up most of
290 autoconf's warnings about AC_TRY_RUN).
291
292- The Unix build is now a bit less chatty, courtesy of the parser
293 generator. The build is completely silent (except for errors) when
294 using "make -s", thanks to a -q option to setup.py.
295
Tim Petersb07352e2001-09-08 01:25:47 +0000296C API
297
Guido van Rossum624c8af2001-09-18 15:21:04 +0000298- The "structmember" API now supports some new flag bits to deny read
299 and/or write access to attributes in restricted execution mode.
300
Tim Petersb07352e2001-09-08 01:25:47 +0000301New platforms
302
Guido van Rossum624c8af2001-09-18 15:21:04 +0000303- Compaq's iPAQ handheld, running the "familiar" Linux distribution
304 (http://familiar.handhelds.org).
305
Tim Petersb07352e2001-09-08 01:25:47 +0000306Tests
307
Tim Peters8a9c2842001-09-22 21:30:22 +0000308- The "classic" standard tests, which work by comparing stdout to
309 an expected-output file under Lib/test/output/, no longer stop at
310 the first mismatch. Instead the test is run to completion, and a
311 variant of ndiff-style comparison is used to report all differences.
312 This is much easier to understand than the previous style of reporting.
313
314- The unittest-based standard tests now use regrtest's test_main()
315 convention, instead of running as a side-effect of merely being
316 imported. This allows these tests to be run in more natural and
317 flexible ways as unittests, outside the regrtest framework.
318
319- regrtest.py is much better integrated with unittest and doctest now,
320 especially in regard to reporting errors.
321
Tim Petersb07352e2001-09-08 01:25:47 +0000322Windows
323
Guido van Rossum624c8af2001-09-18 15:21:04 +0000324- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000325 that support it (NTFS under Windows 2000). See "What's New in
326 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000327
Tim Petersb07352e2001-09-08 01:25:47 +0000328
Tim Petersedc99312001-08-22 21:36:50 +0000329What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000330Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000331===========================
332
333Core
334
Tim Peters9fffa3e2001-09-04 05:14:19 +0000335- Conversion of long to float now raises OverflowError if the long is too
336 big to represent as a C double.
337
Tim Peters32f453e2001-09-03 08:35:41 +0000338- The 3-argument builtin pow() no longer allows a third non-None argument
339 if either of the first two arguments is a float, or if both are of
340 integer types and the second argument is negative (in which latter case
341 the arguments are converted to float, so this is really the same
342 restriction).
343
Tim Peters5d2b77c2001-09-03 05:47:38 +0000344- The builtin dir() now returns more information, and sometimes much
345 more, generally naming all attributes of an object, and all attributes
346 reachable from the object via its class, and from its class's base
347 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
348 an empty list. In 2.2a3,
349
350 >>> dir([])
351 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
352 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
353 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
354 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
355 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
356 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
357 'reverse', 'sort']
358
359 dir(module) continues to return only the module's attributes, though.
360
Tim Petersbdee63f2001-09-02 03:40:59 +0000361- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000362 than raising OverflowError. This is a partial implementation of PEP
363 237. You can use -Wdefault::OverflowWarning to enable a warning for
364 this situation, and -Werror::OverflowWarning to revert to the old
365 OverflowError exception.
366
Guido van Rossum61c345f2001-09-04 03:26:15 +0000367- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000368 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000369 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
370 -Qold, meaning the / operator has its classic meaning and no
371 warnings are issued. Using -Qwarn issues a run-time warning about
372 all uses of classic division for int and long arguments; -Qwarnall
373 also warns about classic division for float and complex arguments
374 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
375 new division by default, but only in the __main__ module. You can
376 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
377 __main__ module new division, and warns about classic division
378 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000379
Tim Petersbdee63f2001-09-02 03:40:59 +0000380- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000381 long, float, str, unicode, and tuple. (The types complex, list and
382 dictionary can also be subclassed; this was introduced earlier.)
383 Note that restrictions apply when subclassing immutable built-in
384 types: you can only affect the value of the instance by overloading
385 __new__. You can add mutable attributes, and the subclass instances
386 will have a __dict__ attribute, but you cannot change the "value"
387 (as implemented by the base class) of an immutable subclass instance
388 once it is created.
389
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000390- The dictionary constructor now takes an optional argument, a
391 mapping-like object, and initializes the dictionary from its
392 (key, value) pairs.
393
Tim Petersbdee63f2001-09-02 03:40:59 +0000394- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000395 "cooperative super calls" in a multiple inheritance setting. For an
396 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
397
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000398- A new built-in type, property, has been added. This enables the
399 creation of "properties". These are attributes implemented by
400 getter and setter functions (or only one of these for read-only or
401 write-only attributes), without the need to override __getattr__.
402 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000403
Tim Petersbdee63f2001-09-02 03:40:59 +0000404- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000405 liberalized, to allow leading zeroes. Examples of literals now
406 legal that were SyntaxErrors before:
407
408 00.0 0e3 0100j 07.5 00000000000000000008.
409
Tim Petersbdee63f2001-09-02 03:40:59 +0000410- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000411 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
412
Tim Petersedc99312001-08-22 21:36:50 +0000413Library
414
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000415- telnetlib includes symbolic names for the options, and support for
416 setting an option negotiation callback.
417
Tim Petersa40c7932001-09-05 22:36:56 +0000418- The new C standard no longer requires that math libraries set errno to
419 ERANGE on overflow. For platform libraries that exploit this new
420 freedom, Python's overflow-checking was wholly broken. A new overflow-
421 checking scheme attempts to repair that, but may not be reliable on all
422 platforms (C doesn't seem to provide anything both useful and portable
423 in this area anymore).
424
Martin v. Löwis44f86962001-09-05 13:44:54 +0000425- Asynchronous timeout actions are available through the new class
426 threading.Timer.
427
Tim Peters78526162001-09-05 00:53:45 +0000428- math.log and math.log10 now return sensible results for even huge
429 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
430
Tim Petersbdee63f2001-09-02 03:40:59 +0000431- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000432 currently held. See the docs for the imp module.
433
Tim Petersbdee63f2001-09-02 03:40:59 +0000434- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000435 dumps containing ints written on platforms where Python ints are 8 bytes.
436 When read on a box where Python ints are 4 bytes, such values are
437 converted to Python longs.
438
Tim Petersbdee63f2001-09-02 03:40:59 +0000439- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000440 code objects is no longer allowed. This plugs a security hole.
441
Steve Purcell6091cd62001-09-06 16:05:17 +0000442- unittest.TestResult instances no longer store references to tracebacks
443 generated by test failures. This prevents unexpected dangling references
444 to objects that should be garbage collected between tests.
445
Tim Petersedc99312001-08-22 21:36:50 +0000446Tools
447
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000448- Tools/scripts/fixdiv.py has been added which can be used to fix
449 division operators as per PEP 238.
450
Tim Petersedc99312001-08-22 21:36:50 +0000451Build
452
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000453- If you are an adventurous person using Mac OS X you may want to look at
454 Mac/OSX. There is a Makefile there that will build Python as a real Mac
455 application, which can be used for experimenting with Carbon or Cocoa.
456 Discussion of this on pythonmac-sig, please.
457
Tim Peters7eea37e2001-09-04 22:08:56 +0000458C API
459
460- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000461
Tim Peters9fffa3e2001-09-04 05:14:19 +0000462- Note that PyLong_AsDouble can fail! This has always been true, but no
463 callers checked for it. It's more likely to fail now, because overflow
464 errors are properly detected now. The proper way to check:
465
466 double x = PyLong_AsDouble(some_long_object);
467 if (x == -1.0 && PyErr_Occurred()) {
468 /* The conversion failed. */
469 }
470
Tim Petersbdee63f2001-09-02 03:40:59 +0000471- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000472 compile but will not participate in GC. To upgrade an extension
473 module:
474
475 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000476
Neil Schemenauer4042c692001-08-30 15:38:01 +0000477 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
478 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000479
Neil Schemenauer4042c692001-08-30 15:38:01 +0000480 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
481 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000482
Neil Schemenauer4042c692001-08-30 15:38:01 +0000483 - remove PyGC_HEAD_SIZE from object size calculations
484
485 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
486
Tim Petersbdee63f2001-09-02 03:40:59 +0000487- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000488 These can be used safely to construct string objects from a
489 sprintf-style format string (similar to the format string supported
490 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000491
Tim Petersedc99312001-08-22 21:36:50 +0000492New platforms
493
Tim Petersb7da0902001-09-02 23:01:43 +0000494- Stephen Hansen contributed patches sufficient to get a clean compile
495 under Borland C (Windows), but he reports problems running it and ran
496 out of time to complete the port. Volunteers? Expect a MemoryError
497 when importing the types module; this is probably shallow, and
498 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000499
Tim Petersedc99312001-08-22 21:36:50 +0000500Tests
501
502Windows
503
Tim Peters6e13a562001-09-06 00:32:15 +0000504- Large file support is now enabled on Win32 platforms as well as on
505 Win64. This means that, for example, you can use f.tell() and f.seek()
506 to manipulate files larger than 2 gigabytes (provided you have enough
507 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000508 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
509 filesize limit, and large file support makes no difference there.
510 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
511 NTFS has no practical limit on file size, and files of any size can be
512 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000513
Tim Petersbdee63f2001-09-02 03:40:59 +0000514- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000515 points to command.com (patch from Brian Quinlan).
516
Tim Petersedc99312001-08-22 21:36:50 +0000517
Tim Peters20f51a72001-07-21 02:31:40 +0000518What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000519Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000520===========================
521
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000522Build
523
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000524- Tim Peters developed a brand new Windows installer using Wise 8.1,
525 generously donated to us by Wise Solutions.
526
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000527- configure supports a new option --enable-unicode, with the values
528 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
529 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000530
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000531- A new configure option --enable-framework builds a Mac OS X framework,
532 which "make frameworkinstall" will install. This provides a starting
533 point for more mac-like functionality, join pythonmac-sig@python.org
534 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000535
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000536- The NeXT platform is no longer supported.
537
538- The `new' module is now statically linked.
539
Tim Peters0afb6092001-08-15 06:06:44 +0000540Tools
541
542- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000543 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000544 the module docstring for details.
545
Tim Peters20f51a72001-07-21 02:31:40 +0000546Tests
547
Tim Peters5e824c32001-08-12 22:25:01 +0000548- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000549 platforms, allowing to give clearer test result output. regrtest
550 also has optional --use/-u switch to run normally disabled tests
551 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000552
Tim Peters20f51a72001-07-21 02:31:40 +0000553- Several new tests in the standard test suite, with special thanks to
554 Nick Mathewson.
555
556Core
557
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000558- The floor division operator // has been added as outlined in PEP
559 238. The / operator still provides classic division (and will until
560 Python 3.0) unless "from __future__ import division" is included, in
561 which case the / operator will provide true division. The operator
562 module provides truediv() and floordiv() functions. Augmented
563 assignment variants are included, as are the equivalent overloadable
564 methods and C API methods. See the PEP for a full discussion:
565 <http://python.sf.net/peps/pep-0238.html>
566
Tim Peters6cd6a822001-08-17 22:11:27 +0000567- Future statements are now effective in simulated interactive shells
568 (like IDLE). This should "just work" by magic, but read Michael
569 Hudson's "Future statements in simulated shells" PEP 264 for full
570 details: <http://python.sf.net/peps/pep-0264.html>.
571
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000572- The type/class unification (PEP 252-253) was integrated into the
573 trunk and is not so tentative any more (the exact specification of
574 some features is still tentative). A lot of work has done on fixing
575 bugs and adding robustness and features (performance still has to
576 come a long way).
577
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000578- Warnings about a mismatch in the Python API during extension import
579 now use the Python warning framework (which makes it possible to
580 write filters for these warnings).
581
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000582- A function's __dict__ (aka func_dict) will now always be a
583 dictionary. It used to be possible to delete it or set it to None,
584 but now both actions raise TypeErrors. It is still legal to set it
585 to a dictionary object. Getting func.__dict__ before any attributes
586 have been assigned now returns an empty dictionary instead of None.
587
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000588- A new command line option, -E, was added which disables the use of
589 all environment variables, or at least those that are specifically
590 significant to Python. Usually those have a name starting with
591 "PYTHON". This was used to fix a problem where the tests fail if
592 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
593 older distribution.
594
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000595Library
596
Tim Peters5e824c32001-08-12 22:25:01 +0000597- New class Differ and new functions ndiff() and restore() in difflib.py.
598 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000599 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000600
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000601- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
602 value using the minimal quoting required for the value; more
603 reliable than using xml.sax.saxutils.escape() for attribute values.
604
605- Readline completion support for cmd.Cmd was added.
606
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000607- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
608
609- Added function threading.BoundedSemaphore()
610
611- Added Ka-Ping Yee's cgitb.py module.
612
613- The `new' module now exposes the CO_xxx flags.
614
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000615New platforms
616
617C API
618
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000619- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
620 which provide a cross-platform implementations for the
621 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
622 the standard sprintf() and vsprintf() C lib APIs, these versions
623 apply bounds checking on the used buffer which enhances protection
624 against buffer overruns.
625
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000626- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000627 and extensions using different Unicode widths is rendered next to
628 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000629 will result in an ImportError. Unicode extensions writers must make
630 sure to check the Unicode width compatibility in their extensions by
631 using at least one of the mangled Unicode APIs in the extension.
632
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000633- Two new flags METH_NOARGS and METH_O are available in method definition
634 tables to simplify implementation of methods with no arguments and a
635 single untyped argument. Calling such methods is more efficient than
636 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
637 deprecated.
638
Tim Petersc1731372001-08-04 08:12:36 +0000639Windows
640
641- "import module" now compiles module.pyw if it exists and nothing else
642 relevant is found.
643
Tim Peters20f51a72001-07-21 02:31:40 +0000644
Guido van Rossum55a78992001-07-17 17:22:32 +0000645What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000646===========================
647
648Core
Tim Petersa814db52001-05-14 07:05:58 +0000649
Tim Peters6d6c1a32001-08-02 04:15:00 +0000650- TENTATIVELY, a large amount of code implementing much of what's
651 described in PEP 252 (Making Types Look More Like Classes) and PEP
652 253 (Subtyping Built-in Types) was added. This will be released
653 with Python 2.2a1. Documentation will be provided separately
654 through http://www.python.org/2.2/. The purpose of releasing this
655 with Python 2.2a1 is to test backwards compatibility. It is
656 possible, though not likely, that a decision is made not to release
657 this code as part of 2.2 final, if any serious backwards
658 incompapatibilities are found during alpha testing that cannot be
659 repaired.
660
Guido van Rossum55a78992001-07-17 17:22:32 +0000661- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000662 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000663 more 'yield' statements. See PEP 255. Since this adds a new
664 keyword to the language, this feature must be enabled by including a
665 future statement: "from __future__ import generators" (see PEP 236).
666 Generators will become a standard feature in a future release
667 (probably 2.3). Without this future statement, 'yield' remains an
668 ordinary identifier, but a warning is issued each time it is used.
669 (These warnings currently don't conform to the warnings framework of
670 PEP 230; we intend to fix this in 2.2a2.)
671
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000672- The UTF-16 codec was modified to be more RFC compliant. It will now
673 only remove BOM characters at the start of the string and then
674 only if running in native mode (UTF-16-LE and -BE won't remove a
675 leading BMO character).
676
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000677- Strings now have a new method .decode() to complement the already
678 existing .encode() method. These two methods provide direct access
679 to the corresponding decoders and encoders of the registered codecs.
680
681 To enhance the usability of the .encode() method, the special
682 casing of Unicode object return values was dropped (Unicode objects
683 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000684
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000685 Both methods will now return whatever the codec in charge of the
686 requested encoding returns as object, e.g. Unicode codecs will
687 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
688 will return u"äöü"). This enables codec writer to create codecs
689 for various simple to use conversions.
690
691 New codecs were added to demonstrate these new features (the .encode()
692 and .decode() columns indicate the type of the returned objects):
693
694 Name | .encode() | .decode() | Description
695 ----------------------------------------------------------------------
696 uu | string | string | UU codec (e.g. for email)
697 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000698 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000699 zlib | string | string | zlib compression
700 hex | string | string | 2-byte hex codec
701 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
702
Mark Hammond2a0af792001-05-14 03:09:36 +0000703- Some operating systems now support the concept of a default Unicode
704 encoding for file system operations. Notably, Windows supports 'mbcs'
705 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000706 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000707 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000708
709 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000710 functions that return filenames (such as os.listdir()) to return Python
711 string objects pre-encoded using the default file system encoding for
712 the platform. As this encoding is likely to be different from Python's
713 default encoding, converting this name to a Unicode object before passing
714 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000715 would attempt to use its default encoding (generally ASCII) rather than
716 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000717
Tim Petersa814db52001-05-14 07:05:58 +0000718 In general, this change simply removes surprises when working with
719 Unicode and the file system, making these operations work as you expect,
720 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000721 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000722
Tim Peters61dff2b2001-05-08 15:43:37 +0000723- Float (and complex) literals in source code were evaluated to full
724 precision only when running from a .py file; the same code loaded from a
725 .pyc (or .pyo) file could suffer numeric differences starting at about the
726 12th significant decimal digit. For example, on a machine with IEEE-754
727 floating arithmetic,
728
729 x = 9007199254740992.0
730 print long(x)
731
732 printed 9007199254740992 if run directly from .py, but 9007199254740000
733 if from a compiled (.pyc or .pyo) file. This was due to marshal using
734 str(float) instead of repr(float) when building code objects. marshal
735 now uses repr(float) instead, which should reproduce floats to full
736 machine precision (assuming the platform C float<->string I/O conversion
737 functions are of good quality).
738
739 This may cause floating-point results to change in some cases, and
740 usually for the better, but may also cause numerically unstable
741 algorithms to break.
742
Tim Peters2f228e72001-05-13 00:19:31 +0000743- The implementation of dicts suffers fewer collisions, which has speed
744 benefits. However, the order in which dict entries appear in dict.keys(),
745 dict.values() and dict.items() may differ from previous releases for a
746 given dict. Nothing is defined about this order, so no program should
747 rely on it. Nevertheless, it's easy to write test cases that rely on the
748 order by accident, typically because of printing the str() or repr() of a
749 dict to an "expected results" file. See Lib/test/test_support.py's new
750 sortdict(dict) function for a simple way to display a dict in sorted
751 order.
752
Tim Peters7a3bfc32001-06-12 01:22:22 +0000753- Many other small changes to dicts were made, resulting in faster
754 operation along the most common code paths.
755
Guido van Rossum10315822001-05-01 20:54:30 +0000756- Dictionary objects now support the "in" operator: "x in dict" means
757 the same as dict.has_key(x).
758
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000759- The update() method of dictionaries now accepts generic mapping
760 objects. Specifically the argument object must support the .keys()
761 and __getitem__() methods. This allows you to say, for example,
762 {}.update(UserDict())
763
Guido van Rossum10315822001-05-01 20:54:30 +0000764- Iterators were added; this is a generalized way of providing values
765 to a for loop. See PEP 234. There's a new built-in function iter()
766 to return an iterator. There's a new protocol to get the next value
767 from an iterator using the next() method (in Python) or the
768 tp_iternext slot (in C). There's a new protocol to get iterators
769 using the __iter__() method (in Python) or the tp_iter slot (in C).
770 Iterating (i.e. a for loop) over a dictionary generates its keys.
771 Iterating over a file generates its lines.
772
Tim Petersf553f892001-05-01 20:45:31 +0000773- The following functions were generalized to work nicely with iterator
774 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000775 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000776 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
777 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000778 join() method of strings
779 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000780 'x in y' and 'x not in y' (PySequence_Contains() in C API)
781 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000782 right-hand side of assignment statements with multiple targets, such as
783 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000784
Tim Petersd85e1022001-05-11 21:51:48 +0000785- Accessing module attributes is significantly faster (for example,
786 random.random or os.path or yourPythonModule.yourAttribute).
787
Tim Peterse63415e2001-05-08 04:38:29 +0000788- Comparing dictionary objects via == and != is faster, and now works even
789 if the keys and values don't support comparisons other than ==.
790
Tim Peters95bf9392001-05-10 08:32:44 +0000791- Comparing dictionaries in ways other than == and != is slower: there were
792 insecurities in the dict comparison implementation that could cause Python
793 to crash if the element comparison routines for the dict keys and/or
794 values mutated the dicts. Making the code bulletproof slowed it down.
795
Tim Peterseb28ef22001-06-02 05:27:19 +0000796- Collisions in dicts are resolved via a new approach, which can help
797 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000798 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000799 faster now. Thanks to Christian Tismer for pointing out the cause and
800 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000801
Tim Peters52e155e2001-06-16 05:42:57 +0000802- repr() is much faster for large containers (dict, list, tuple).
803
804
Tim Petersa814db52001-05-14 07:05:58 +0000805Library
806
Fred Drake960fdf92001-07-20 18:38:26 +0000807- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
808 were added to the string module. These a locale-indenpendent
809 constants, unlike letters, lowercase, and uppercase. These are now
810 use in appropriate locations in the standard library.
811
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000812- The flags used in dlopen calls can now be configured using
813 sys.setdlopenflags and queried using sys.getdlopenflags.
814
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000815- Fredrik Lundh's xmlrpclib is now a standard library module. This
816 provides full client-side XML-RPC support. In addition,
817 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
818 one asyncore-based). Thanks to Eric Raymond for the documentation.
819
Guido van Rossum643d3912001-07-05 14:46:25 +0000820- The xrange() object is simplified: it no longer supports slicing,
821 repetition, comparisons, efficient 'in' checking, the tolist()
822 method, or the start, stop and step attributes. See PEP 260.
823
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000824- A new function fnmatch.filter to filter lists of file names was added.
825
Barry Warsawffd674d2001-05-22 16:00:10 +0000826- calendar.py uses month and day names based on the current locale.
827
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000828- strop is now *really* obsolete (this was announced before with 1.6),
829 and issues DeprecationWarning when used (except for the four items
830 that are still imported into string.py).
831
Tim Petersa814db52001-05-14 07:05:58 +0000832- Cookie.py now sorts key+value pairs by key in output strings.
833
834- pprint.isrecursive(object) didn't correctly identify recursive objects.
835 Now it does.
836
Tim Peters95b3f782001-05-14 18:39:41 +0000837- pprint functions now much faster for large containers (tuple, list, dict).
838
Tim Peters7b9542a2001-06-10 23:40:19 +0000839- New 'q' and 'Q' format codes in the struct module, corresponding to C
840 types "long long" and "unsigned long long" (on Windows, __int64). In
841 native mode, these can be used only when the platform C compiler supports
842 these types (when HAVE_LONG_LONG is #define'd by the Python config
843 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000844 In standard mode, 'q' and 'Q' are supported on all platforms, and are
845 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000846
Guido van Rossum83213cc2001-06-12 16:48:52 +0000847- The site module installs a new built-in function 'help' that invokes
848 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
849 it displays a message reminding the user to use 'help()' or
850 'help(object)'.
851
Tim Petersa814db52001-05-14 07:05:58 +0000852Tests
853
854- New test_mutants.py runs dict comparisons where the key and value
855 comparison operators mutute the dicts randomly during comparison. This
856 rapidly causes Python to crash under earlier releases (not for the faint
857 of heart: it can also cause Win9x to freeze or reboot!).
858
859- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000860 pprint.isreadable() return sensible results. Also verifies that simple
861 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000862
Tim Peters4324aa32001-05-28 22:30:08 +0000863C API
864
865- Removed the unused last_is_sticky argument from the internal
866 _PyTuple_Resize(). If this affects you, you were cheating.
867
868
Guido van Rossum55a78992001-07-17 17:22:32 +0000869======================================================================
870
871
Guido van Rossumffe13be2001-04-16 18:46:45 +0000872What's New in Python 2.1 (final)?
873=================================
874
875We only changed a few things since the last release candidate, all in
876Python library code:
877
878- A bug in the locale module was fixed that affected locales which
879 define no grouping for numeric formatting.
880
881- A few bugs in the weakref module's implementations of weak
882 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
883 and the test suite was updated to check for these bugs.
884
885- An old bug in the os.path.walk() function (introduced in Python
886 2.0!) was fixed: a non-existent file would cause an exception
887 instead of being ignored.
888
889- Fixed a few bugs in the new symtable module found by Neil Norwitz's
890 PyChecker.
891
892
Guido van Rossum5b08f132001-04-16 02:05:23 +0000893What's New in Python 2.1c2?
894===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000895
Guido van Rossum5b08f132001-04-16 02:05:23 +0000896A flurry of small changes, and one showstopper fixed in the nick of
897time made it necessary to release another release candidate. The list
898here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000899
Guido van Rossum5b08f132001-04-16 02:05:23 +0000900Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000901
Guido van Rossum5b08f132001-04-16 02:05:23 +0000902- Tim discovered a nasty bug in the dictionary code, caused by
903 PyDict_Next() calling dict_resize(), and the GC code's use of
904 PyDict_Next() violating an assumption in dict_items(). This was
905 fixed with considerable amounts of band-aid, but the net effect is a
906 saner and more robust implementation.
907
908- Made a bunch of symbols static that were accidentally global.
909
910Build and Ports
911
912- The setup.py script didn't check for a new enough version of zlib
913 (1.1.3 is needed). Now it does.
914
915- Changed "make clean" target to also remove shared libraries.
916
917- Added a more general warning about the SGI Irix optimizer to README.
918
919Library
920
921- Fix a bug in urllib.basejoin("http://host", "../file.html") which
922 omitted the slash between host and file.html.
923
924- The mailbox module's _Mailbox class contained a completely broken
925 and undocumented seek() method. Ripped it out.
926
927- Fixed a bunch of typos in various library modules (urllib2, smtpd,
928 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
929
930- Fixed a few last-minute bugs in unittest.
931
932Extensions
933
934- Reverted the patch to the OpenSSL code in socketmodule.c to support
935 RAND_status() and the EGD, and the subsequent patch that tried to
936 fix it for pre-0.9.5 versions; the problem with the patch is that on
937 some systems it issues a warning whenever socket is imported, and
938 that's unacceptable.
939
940Tests
941
942- Fixed the pickle tests to work with "import test.test_pickle".
943
944- Tweaked test_locale.py to actually run the test Windows.
945
946- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
947 not "wb" (which is not a valid mode at all).
948
949- Fix pstats browser crashes. Import readline if it exists to make
950 the user interface nicer.
951
952- Add "import thread" to the top of test modules that import the
953 threading module (test_asynchat and test_threadedtempfile). This
954 prevents test failures caused by a broken threading module resulting
955 from a previously caught failed import.
956
957- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
958 needed on some platforms (e.g. Solaris 8) when the tests are run
959 twice in succession.
960
961- Skip rather than fail test_sunaudiodev if no audio device is found.
962
963
964What's New in Python 2.1c1?
965===========================
966
967This list was significantly updated when 2.1c2 was released; the 2.1c1
968release didn't mention most changes that were actually part of 2.1c1:
969
970Legal
971
972- Copyright was assigned to the Python Software Foundation (PSF) and a
973 PSF license (very similar to the CNRI license) was added.
974
975- The CNRI copyright notice was updated to include 2001.
976
977Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000978
Guido van Rossumc9932722001-04-12 02:31:27 +0000979- After a public outcry, assignment to __debug__ is no longer illegal;
980 instead, a warning is issued. It will become illegal in 2.2.
981
Guido van Rossum5b08f132001-04-16 02:05:23 +0000982- Fixed a core dump with "%#x" % 0, and changed the semantics so that
983 "%#x" now always prepends "0x", even if the value is zero.
984
985- Fixed some nits in the bytecode compiler.
986
987- Fixed core dumps when calling certain kinds of non-functions.
988
989- Fixed various core dumps caused by reference count bugs.
990
991Build and Ports
992
993- Use INSTALL_SCRIPT to install script files.
994
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000995- New port: SCO Unixware 7, by Billy G. Allie.
996
Guido van Rossum5b08f132001-04-16 02:05:23 +0000997- Updated RISCOS port.
998
999- Updated BeOS port and notes.
1000
1001- Various other porting problems resolved.
1002
1003Library
1004
1005- The TERMIOS and SOCKET modules are now truly obsolete and
1006 unnecessary. Their symbols are incorporated in the termios and
1007 socket modules.
1008
1009- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1010 better tests for pickling.
1011
1012- threading: make Condition.wait() robust against KeyboardInterrupt.
1013
1014- zipfile: add support to zipfile to support opening an archive
1015 represented by an open file rather than a file name. Fix bug where
1016 the archive was not properly closed. Fixed a bug in this bugfix
1017 where flush() was called for a read-only file.
1018
1019- imputil: added an uninstall() method to the ImportManager.
1020
1021- Canvas: fixed bugs in lower() and tkraise() methods.
1022
1023- SocketServer: API change (added overridable close_request() method)
1024 so that the TCP server can explicitly close the request.
1025
1026- pstats: Eric Raymond added a simple interactive statistics browser,
1027 invoked when the module is run as a script.
1028
1029- locale: fixed a problem in format().
1030
1031- webbrowser: made it work when the BROWSER environment variable has a
1032 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1033 KDE 2. Fixed some other nits.
1034
1035- unittest: changes to allow using a different exception than
1036 AssertionError, and added a few more function aliases. Some other
1037 small changes.
1038
1039- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1040
1041- asynchat: fixed a critical bug in asynchat that slipped through the
1042 2.1b2 release. Fixed another rare bug.
1043
1044- Fix some unqualified except: clauses (always a bad code example).
1045
1046XML
1047
1048- pyexpat: new API get_version_string().
1049
1050- Fixed some minidom bugs.
1051
1052Extensions
1053
1054- Fixed a core dump in _weakref. Removed the weakref.mapping()
1055 function (it adds nothing to the API).
1056
1057- Rationalized the use of header files in the readline module, to make
1058 it compile (albeit with some warnings) with the very recent readline
1059 4.2, without breaking for earlier versions.
1060
1061- Hopefully fixed a buffering problem in linuxaudiodev.
1062
1063- Attempted a fix to make the OpenSSL support in the socket module
1064 work again with pre-0.9.5 versions of OpenSSL.
1065
1066Tests
1067
1068- Added a test case for asynchat and asyncore.
1069
1070- Removed coupling between tests where one test failing could break
1071 another.
1072
1073Tools
1074
1075- Ping added an interactive help browser to pydoc, fixed some nits
1076 in the rest of the pydoc code, and added some features to his
1077 inspect module.
1078
1079- An updated python-mode.el version 4.1 which integrates Ken
1080 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1081 much nicer in XEmacs and Emacs. When stepping through your program
1082 with pdb, in either the shell window or the *Python* window, the
1083 source file and line will be tracked by an arrow. Very cool!
1084
1085- IDLE: syntax warnings in interactive mode are changed into errors.
1086
1087- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001088 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001089
1090- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001091
Barry Warsaw11e89c72001-04-11 20:37:57 +00001092
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001093What's New in Python 2.1 beta 2?
1094================================
1095
Guido van Rossum053ae352001-03-22 14:17:21 +00001096(Unlisted are many fixed bugs, more documentation, etc.)
1097
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001098Core language, builtins, and interpreter
1099
Guido van Rossum053ae352001-03-22 14:17:21 +00001100- The nested scopes work (enabled by "from __future__ import
1101 nested_scopes") is completed; in particular, the future now extends
1102 into code executed through exec, eval() and execfile(), and into the
1103 interactive interpreter.
1104
1105- When calling a base class method (e.g. BaseClass.__init__(self)),
1106 this is now allowed even if self is not strictly spoken a class
1107 instance (e.g. when using metaclasses or the Don Beaudry hook).
1108
1109- Slice objects are now comparable but not hashable; this prevents
1110 dict[:] from being accepted but meaningless.
1111
1112- Complex division is now calculated using less braindead algorithms.
1113 This doesn't change semantics except it's more likely to give useful
1114 results in extreme cases. Complex repr() now uses full precision
1115 like float repr().
1116
1117- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1118
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001119- It is illegal to assign to the name __debug__, which is set when the
1120 interpreter starts. It is effectively a compile-time constant.
1121
1122- A warning will be issued if a global statement for a variable
1123 follows a use or assignment of that variable.
1124
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001125Standard library
1126
Guido van Rossum053ae352001-03-22 14:17:21 +00001127- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1128 inspired by JUnit), is now part of the standard library. You now
1129 have a choice of two testing frameworks: unittest requires you to
1130 write testcases as separate code, doctest gathers them from
1131 docstrings. Both approaches have their advantages and
1132 disadvantages.
1133
1134- A new module Tix was added, which wraps the Tix extension library
1135 for Tk. With that module, it is not necessary to statically link
1136 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1137 require" command. See Demo/tix/.
1138
1139- tzparse.py is now obsolete.
1140
1141- In gzip.py, the seek() and tell() methods are removed -- they were
1142 non-functional anyway, and it's better if callers can test for their
1143 existence with hasattr().
1144
1145Python/C API
1146
1147- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1148 that's already in the dictionary during a PyDict_Next() iteration.
1149 This used to fail occasionally when a dictionary resize operation
1150 could be triggered that would rehash all the keys. All other
1151 modifications to the dictionary are still off-limits during a
1152 PyDict_Next() iteration!
1153
1154- New extended APIs related to passing compiler variables around.
1155
1156- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1157 implement isinstance() and issubclass().
1158
1159- Py_BuildValue() now has a "D" conversion to create a Python complex
1160 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001161
Fred Drake4e262a92001-03-22 18:26:47 +00001162- Extensions types which support weak references must now set the
1163 field allocated for the weak reference machinery to NULL themselves;
1164 this is done to avoid the cost of checking each object for having a
1165 weakly referencable type in PyObject_INIT(), since most types are
1166 not weakly referencable.
1167
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001168- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1169 free variables and cell variables to and from the frame's f_locals.
1170
1171- Variants of several functions defined in pythonrun.h have been added
1172 to support the nested_scopes future statement. The variants all end
1173 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1174 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1175 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001176 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001177
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001178Distutils
1179
1180- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1181 into the release tree.
1182
Tim Peters0e57abf2001-05-02 07:39:38 +00001183- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001184 (an uninstaller, more customization of the installer's display)
1185
1186- from Jack Jansen: added Mac-specific code to generate a dialog for
1187 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001188 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001189 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001190
1191- added 'platforms' and 'keywords' to the set of metadata that can be
1192 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001193
1194- applied patches from Jason Tishler to make the compiler class work with
1195 Cygwin.
1196
1197
Tim Peters2fe289a2001-03-01 22:19:38 +00001198What's New in Python 2.1 beta 1?
1199================================
Tim Petersd66595f2001-02-04 03:09:53 +00001200
1201Core language, builtins, and interpreter
1202
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001203- Following an outcry from the community about the amount of code
1204 broken by the nested scopes feature introduced in 2.1a2, we decided
1205 to make this feature optional, and to wait until Python 2.2 (or at
1206 least 6 months) to make it standard. The option can be enabled on a
1207 per-module basis by adding "from __future__ import nested_scopes" at
1208 the beginning of a module (before any other statements, but after
1209 comments and an optional docstring). See PEP 236 (Back to the
1210 __future__) for a description of the __future__ statement. PEP 227
1211 (Statically Nested Scopes) has been updated to reflect this change,
1212 and to clarify the semantics in a number of endcases.
1213
1214- The nested scopes code, when enabled, has been hardened, and most
1215 bugs and memory leaks in it have been fixed.
1216
1217- Compile-time warnings are now generated for a number of conditions
1218 that will break or change in meaning when nested scopes are enabled:
1219
1220 - Using "from...import *" or "exec" without in-clause in a function
1221 scope that also defines a lambda or nested function with one or
1222 more free (non-local) variables. The presence of the import* or
1223 bare exec makes it impossible for the compiler to determine the
1224 exact set of local variables in the outer scope, which makes it
1225 impossible to determine the bindings for free variables in the
1226 inner scope. To avoid the warning about import *, change it into
1227 an import of explicitly name object, or move the import* statement
1228 to the global scope; to avoid the warning about bare exec, use
1229 exec...in... (a good idea anyway -- there's a possibility that
1230 bare exec will be deprecated in the future).
1231
1232 - Use of a global variable in a nested scope with the same name as a
1233 local variable in a surrounding scope. This will change in
1234 meaning with nested scopes: the name in the inner scope will
1235 reference the variable in the outer scope rather than the global
1236 of the same name. To avoid the warning, either rename the outer
1237 variable, or use a global statement in the inner function.
1238
Neil Schemenauera35c6882001-02-27 04:45:05 +00001239- An optional object allocator has been included. This allocator is
1240 optimized for Python objects and should be faster and use less memory
1241 than the standard system allocator. It is not enabled by default
1242 because of possible thread safety problems. The allocator is only
1243 protected by the Python interpreter lock and it is possible that some
1244 extension modules require a thread safe allocator. The object
1245 allocator can be enabled by providing the "--with-pymalloc" option to
1246 configure.
1247
Tim Petersd66595f2001-02-04 03:09:53 +00001248Standard library
1249
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001250- pyexpat now detects the expat version if expat.h defines it. A
1251 number of additional handlers are provided, which are only available
1252 since expat 1.95. In addition, the methods SetParamEntityParsing and
1253 GetInputContext of Parser objects are available with 1.95.x
1254 only. Parser objects now provide the ordered_attributes and
1255 specified_attributes attributes. A new module expat.model was added,
1256 which offers a number of additional constants if 1.95.x is used.
1257
1258- xml.dom offers the new functions registerDOMImplementation and
1259 getDOMImplementation.
1260
1261- xml.dom.minidom offers a toprettyxml method. A number of DOM
1262 conformance issues have been resolved. In particular, Element now
1263 has an hasAttributes method, and the handling of namespaces was
1264 improved.
1265
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001266- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1267 getting information about live Python code, and pydoc.py, a module
1268 for interactively converting docstrings to HTML or text.
1269 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001270 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001271 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1272 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001273
Tim Peters1eff7962001-03-01 02:31:33 +00001274- New library module difflib.py, primarily packaging the SequenceMatcher
1275 class at the heart of the popular ndiff.py file-comparison tool.
1276
1277- doctest.py (a framework for verifying Python code examples in docstrings)
1278 is now part of the std library.
1279
Tim Petersd66595f2001-02-04 03:09:53 +00001280Windows changes
1281
Guido van Rossume3955a82001-03-02 14:05:59 +00001282- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1283 small GUI that lets you browse the module docstrings using your
1284 default web browser.
1285
Tim Peters1eff7962001-03-01 02:31:33 +00001286- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1287 Platforms) is implemented. See
1288
1289 http://python.sourceforge.net/peps/pep-0235.html
1290
1291 for full details, especially the "Current Lower-Left Semantics" section.
1292 The new Windows import rules are simpler than before:
1293
1294 A. If the PYTHONCASEOK environment variable exists, same as
1295 before: silently accept the first case-insensitive match of any
1296 kind; raise ImportError if none found.
1297
1298 B. Else search sys.path for the first case-sensitive match; raise
1299 ImportError if none found.
1300
1301 The same rules have been implented on other platforms with case-
1302 insensitive but case-preserving filesystems too (including Cygwin, and
1303 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001304
Tim Peters25a9ce32001-02-19 07:06:36 +00001305- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1306 what it's supposed to do (and does do under NT and 2000) via direct
1307 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001308 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001309 all Win9x systems before.
1310
Tim Peters1eff7962001-03-01 02:31:33 +00001311- Build: Subproject _test (effectively) renamed to _testcapi.
1312
Tim Peters2fe289a2001-03-01 22:19:38 +00001313New platforms
1314
1315- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1316 Thanks to Steven Majewski!
1317
1318- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1319 Tishler!
1320
Guido van Rossum9089b272001-03-02 06:49:50 +00001321- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1322 Schwertberger! See RISCOS/README for more information -- it seems
1323 that because of the bizarre filename conventions on RISCOS, no port
1324 to that platform is easy. Note that the new variable os.endsep is
1325 silently supported in order to make life easier on this platform,
1326 but we don't advertise it because it's not worth for most folks to
1327 care about RISCOS portability.
1328
Tim Peters25a9ce32001-02-19 07:06:36 +00001329
Tim Petersd7b5e882001-01-25 03:36:26 +00001330What's New in Python 2.1 alpha 2?
1331=================================
Tim Peters40ead762001-01-27 05:35:26 +00001332
Tim Petersd7b5e882001-01-25 03:36:26 +00001333Core language, builtins, and interpreter
1334
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001335- Scopes nest. If a name is used in a function or class, but is not
1336 local, the definition in the nearest enclosing function scope will
1337 be used. One consequence of this change is that lambda statements
1338 could reference variables in the namespaces where the lambda is
1339 defined. In some unusual cases, this change will break code.
1340
1341 In all previous version of Python, names were resolved in exactly
1342 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001343 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001344 function A is defined within a function B, the names bound in B are
1345 not visible in A. The new rules make names bound in B visible in A,
1346 unless A contains a name binding that hides the binding in B.
1347
1348 Section 4.1 of the reference manual describes the new scoping rules
1349 in detail. The test script in Lib/test/test_scope.py demonstrates
1350 some of the effects of the change.
1351
1352 The new rules will cause existing code to break if it defines nested
1353 functions where an outer function has local variables with the same
1354 name as globals or builtins used by the inner function. Example:
1355
1356 def munge(str):
1357 def helper(x):
1358 return str(x)
1359 if type(str) != type(''):
1360 str = helper(str)
1361 return str.strip()
1362
1363 Under the old rules, the name str in helper() is bound to the
1364 builtin function str(). Under the new rules, it will be bound to
1365 the argument named str and an error will occur when helper() is
1366 called.
1367
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001368- The compiler will report a SyntaxError if "from ... import *" occurs
1369 in a function or class scope. The language reference has documented
1370 that this case is illegal, but the compiler never checked for it.
1371 The recent introduction of nested scope makes the meaning of this
1372 form of name binding ambiguous. In a future release, the compiler
1373 may allow this form when there is no possibility of ambiguity.
1374
Tim Peters40ead762001-01-27 05:35:26 +00001375- repr(string) is easier to read, now using hex escapes instead of octal,
1376 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1377
1378 >>> "\texample \r\n" + chr(0) + chr(255)
1379 '\texample \r\n\x00\xff' # in 2.1
1380 '\011example \015\012\000\377' # in 2.0
1381
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001382- Functions are now compared and hashed by identity, not by value, since
1383 the func_code attribute is writable.
1384
Fred Drakefb9d7122001-02-01 20:00:40 +00001385- Weak references (PEP 205) have been added. This involves a few
1386 changes in the core, an extension module (_weakref), and a Python
1387 module (weakref). The weakref module is the public interface. It
1388 includes support for "explicit" weak references, proxy objects, and
1389 mappings with weakly held values.
1390
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001391- A 'continue' statement can now appear in a try block within the body
1392 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001393 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001394
Tim Petersd7b5e882001-01-25 03:36:26 +00001395Standard library
1396
Barry Warsaw30dbd142001-01-31 22:14:01 +00001397- mailbox.py now has a new class, PortableUnixMailbox which is
1398 identical to UnixMailbox but uses a more portable scheme for
1399 determining From_ separators. Also, the constructors for all the
1400 classes in this module have a new optional `factory' argument, which
1401 is a callable used when new message classes must be instantiated by
1402 the next() method.
1403
Tim Petersd7b5e882001-01-25 03:36:26 +00001404- random.py is now self-contained, and offers all the functionality of
1405 the now-deprecated whrandom.py. See the docs for details. random.py
1406 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001407 and restoring the internal state of the generator; and jumpahead(n),
1408 for quickly forcing the internal state to be the same as if n calls to
1409 random() had been made. The latter is particularly useful for multi-
1410 threaded programs, creating one instance of the random.Random() class for
1411 each thread, then using .jumpahead() to force each instance to use a
1412 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001413
Tim Peters0de88fc2001-02-01 04:59:18 +00001414- random.py's seed() function is new. For bit-for-bit compatibility with
1415 prior releases, use the whseed function instead. The new seed function
1416 addresses two problems: (1) The old function couldn't produce more than
1417 about 2**24 distinct internal states; the new one about 2**45 (the best
1418 that can be done in the Wichmann-Hill generator). (2) The old function
1419 sometimes produced identical internal states when passed distinct
1420 integers, and there was no simple way to predict when that would happen;
1421 the new one guarantees to produce distinct internal states for all
1422 arguments in [0, 27814431486576L).
1423
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001424- The socket module now supports raw packets on Linux. The socket
1425 family is AF_PACKET.
1426
Tim Peters9ea17ac2001-02-02 05:57:15 +00001427- test_capi.py is a start at running tests of the Python C API. The tests
1428 are implemented by the new Modules/_testmodule.c.
1429
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001430- A new extension module, _symtable, provides provisional access to the
1431 internal symbol table used by the Python compiler. A higher-level
1432 interface will be added on top of _symtable in a future release.
1433
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001434- Removed the obsolete soundex module.
1435
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001436- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1437 the isSameNode method; NamedNodeMap the get method.
1438
1439- xml.sax.expatreader supports the lexical handler property; it
1440 generates comment, startCDATA, and endCDATA events.
1441
Tim Petersee826f82001-01-31 19:39:44 +00001442Windows changes
1443
1444- Build procedure: the zlib project is built in a different way that
1445 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001446 the zlib binary used. See PCbuild\readme.txt for details. Your old
1447 zlib-related directories can be deleted; you'll need to download fresh
1448 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001449
Tim Peters9ea17ac2001-02-02 05:57:15 +00001450- Build: New subproject _test for the benefit of test_capi.py (see above).
1451
Tim Petersb16c56f2001-02-02 21:24:51 +00001452- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1453 interface to some Python compiler internals).
1454
1455- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001456 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001457
Tim Petersa3a3a032000-11-30 05:22:44 +00001458What's New in Python 2.1 alpha 1?
1459=================================
1460
1461Core language, builtins, and interpreter
1462
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001463- There is a new Unicode companion to the PyObject_Str() API
1464 called PyObject_Unicode(). It behaves in the same way as the
1465 former, but assures that the returned value is an Unicode object
1466 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001467
Guido van Rossumf98eda02001-01-17 15:54:45 +00001468- The comparison operators support "rich comparison overloading" (PEP
1469 207). C extension types can provide a rich comparison function in
1470 the new tp_richcompare slot in the type object. The cmp() function
1471 and the C function PyObject_Compare() first try the new rich
1472 comparison operators before trying the old 3-way comparison. There
1473 is also a new C API PyObject_RichCompare() (which also falls back on
1474 the old 3-way comparison, but does not constrain the outcome of the
1475 rich comparison to a Boolean result).
1476
1477 The rich comparison function takes two objects (at least one of
1478 which is guaranteed to have the type that provided the function) and
1479 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1480 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1481 object, which may be NotImplemented (in which case the tp_compare
1482 slot function is used as a fallback, if defined).
1483
1484 Classes can overload individual comparison operators by defining one
1485 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001486 __ge__. There are no explicit "reflected argument" versions of
1487 these; instead, __lt__ and __gt__ are each other's reflection,
1488 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1489 reflection (similar at the C level). No other implications are
1490 made; in particular, Python does not assume that == is the Boolean
1491 inverse of !=, or that < is the Boolean inverse of >=. This makes
1492 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001493
1494 Classes or types that want to implement (in)equality tests but not
1495 the ordering operators (i.e. unordered types) should implement ==
1496 and !=, and raise an error for the ordering operators.
1497
Guido van Rossuma88479f2001-01-18 14:28:08 +00001498 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001499 Boolean; e.g. a matrix type might want to return a matrix of bits
1500 for A < B, giving elementwise comparisons. Such types should ensure
1501 that any interpretation of their value in a Boolean context raises
1502 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1503 at the C level) to always raise an exception.
1504
Guido van Rossuma88479f2001-01-18 14:28:08 +00001505- Complex numbers use rich comparisons to define == and != but raise
1506 an exception for <, <=, > and >=. Unfortunately, this also means
1507 that cmp() of two complex numbers raises an exception when the two
1508 numbers differ. Since it is not mathematically meaningful to compare
1509 complex numbers except for equality, I hope that this doesn't break
1510 too much code.
1511
Tim Peters3389f192001-02-18 08:48:49 +00001512- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001513 not defined by the language, other than that it's arbitrary but
1514 consistent (see the Reference Manual). An implementation detail changed
1515 in 2.1a1 such that None now compares less than any other object. Code
1516 relying on this new behavior (like code that relied on the previous
1517 behavior) does so at its own risk.
1518
Barry Warsaw573b5412001-01-15 20:43:18 +00001519- Functions and methods now support getting and setting arbitrarily
1520 named attributes (PEP 232). Functions have a new __dict__
1521 (a.k.a. func_dict) which hold the function attributes. Methods get
1522 and set attributes on their underlying im_func. It is a TypeError
1523 to set an attribute on a bound method.
1524
Guido van Rossum051e3352001-01-15 19:11:10 +00001525- The xrange() object implementation has been improved so that
1526 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1527 limitation that in this case len(xrange(sys.maxint)) can't be
1528 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1529 work fine as long as the index i doesn't actually reach 2**31.
1530 (Python uses regular ints for sequence and string indices; fixing
1531 that is much more work.)
1532
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001533- Two changes to from...import:
1534
Guido van Rossumba381232001-02-03 15:06:40 +00001535 1) "from M import X" now works even if (after loading module M)
1536 sys.modules['M'] is not a real module; it's basically a getattr()
1537 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001538
1539 2) "from M import *" now looks for M.__all__ to decide which names to
1540 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1541 filters out names starting with '_' as before. Whether or not
1542 __all__ exists, there's no restriction on the type of M.
1543
Guido van Rossumf61f1662001-01-10 20:13:55 +00001544- File objects have a new method, xreadlines(). This is the fastest
1545 way to iterate over all lines in a file:
1546
1547 for line in file.xreadlines():
1548 ...do something to line...
1549
1550 See the xreadlines module (mentioned below) for how to do this for
1551 other file-like objects.
1552
1553- Even if you don't use file.xreadlines(), you may expect a speedup on
1554 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001555 quite a bit in platform-specific ways: on systems (like Linux) that
1556 support flockfile(), getc_unlocked(), and funlockfile(), those are
1557 used by default. On systems (like Windows) without getc_unlocked(),
1558 a complicated (but still thread-safe) method using fgets() is used by
1559 default.
1560
Tim Petersd52269b2001-01-25 06:23:18 +00001561 You can force use of the fgets() method by #define'ing
1562 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001563 getc_unlocked()).
1564
Tim Petersd52269b2001-01-25 06:23:18 +00001565 You can force fgets() not to be used by #define'ing
1566 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001567 test_bufio.py fails -- and let us know if it does!).
1568
1569- In addition, the fileinput module, while still slower than the other
1570 methods on most platforms, has been sped up too, by using
1571 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001572
1573- Support for run-time warnings has been added, including a new
1574 command line option (-W) to specify the disposition of warnings.
1575 See the description of the warnings module below.
1576
1577- Extensive changes have been made to the coercion code. This mostly
1578 affects extension modules (which can now implement mixed-type
1579 numerical operators without having to use coercion), but
1580 occasionally, in boundary cases the coercion semantics have changed
1581 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001582 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001583 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001584 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001585
Guido van Rossumf98eda02001-01-17 15:54:45 +00001586- In connection with the coercion changes, a new built-in singleton
1587 object, NotImplemented is defined. This can be returned for
1588 operations that wish to indicate they are not implemented for a
1589 particular combination of arguments. From C, this is
1590 Py_NotImplemented.
1591
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001592- The interpreter accepts now bytecode files on the command line even
1593 if they do not have a .pyc or .pyo extension. On Linux, after executing
1594
Martin v. Löwise214baa2001-02-04 22:37:56 +00001595import imp,sys,string
1596magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1597reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1598open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001599
1600 any byte code file can be used as an executable (i.e. as an argument
1601 to execve(2)).
1602
Tim Peters9940b802000-12-01 07:59:35 +00001603- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001604 character. In 1.6 and earlier, they never produced a sign,
1605 and raised an error if the value of the long was too large
1606 to fit in a Python int. In 2.0, they produced a sign if and
1607 only if too large to fit in an int. This was inconsistent
1608 across platforms (because the size of an int varies across
1609 platforms), and inconsistent with hex() and oct(). Example:
1610
1611 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001612 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001613 'ffffffbe' # in 2.0 and before, on 32-bit machines
1614 >>> hex(-0x42L)
1615 '-0x42L' # in all versions of Python
1616
Tim Peters9940b802000-12-01 07:59:35 +00001617 The behavior of %d formats for negative Python longs remains
1618 the same as in 2.0 (although in 1.6 and before, they raised
1619 an error if the long didn't fit in a Python int).
1620
1621 %u formats don't make sense for Python longs, but are allowed
1622 and treated the same as %d in 2.1. In 2.0, a negative long
1623 formatted via %u produced a sign if and only if too large to
1624 fit in an int. In 1.6 and earlier, a negative long formatted
1625 via %u raised an error if it was too big to fit in an int.
1626
Guido van Rossum3661d392000-12-12 22:10:31 +00001627- Dictionary objects have an odd new method, popitem(). This removes
1628 an arbitrary item from the dictionary and returns it (in the form of
1629 a (key, value) pair). This can be useful for algorithms that use a
1630 dictionary as a bag of "to do" items and repeatedly need to pick one
1631 item. Such algorithms normally end up running in quadratic time;
1632 using popitem() they can usually be made to run in linear time.
1633
Tim Peters36cdad12000-12-29 02:06:45 +00001634Standard library
1635
Thomas Woutersfe385252001-01-19 23:16:56 +00001636- In the time module, the time argument to the functions strftime,
1637 localtime, gmtime, asctime and ctime is now optional, defaulting to
1638 the current time (in the local timezone).
1639
Guido van Rossumda91f222001-01-15 16:36:08 +00001640- The ftplib module now defaults to passive mode, which is deemed a
1641 more useful default given that clients are often inside firewalls
1642 these days. Note that this could break if ftplib is used to connect
1643 to a *server* that is inside a firewall, from outside; this is
1644 expected to be a very rare situation. To fix that, you can call
1645 ftp.set_pasv(0).
1646
Martin v. Löwis10a27872001-01-13 09:54:41 +00001647- The module site now treats .pth files not only for path configuration,
1648 but also supports extensions to the initialization code: Lines starting
1649 with import are executed.
1650
Guido van Rossumf61f1662001-01-10 20:13:55 +00001651- There's a new module, warnings, which implements a mechanism for
1652 issuing and filtering warnings. There are some new built-in
1653 exceptions that serve as warning categories, and a new command line
1654 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1655 turns warnings into errors). warnings.warn(message[, category])
1656 issues a warning message; this can also be called from C as
1657 PyErr_Warn(category, message).
1658
1659- A new module xreadlines was added. This exports a single factory
1660 function, xreadlines(). The intention is that this code is the
1661 absolutely fastest way to iterate over all lines in an open
1662 file(-like) object:
1663
1664 import xreadlines
1665 for line in xreadlines.xreadlines(file):
1666 ...do something to line...
1667
1668 This is equivalent to the previous the speed record holder using
1669 file.readlines(sizehint). Note that if file is a real file object
1670 (as opposed to a file-like object), this is equivalent:
1671
1672 for line in file.xreadlines():
1673 ...do something to line...
1674
Tim Peters36cdad12000-12-29 02:06:45 +00001675- The bisect module has new functions bisect_left, insort_left,
1676 bisect_right and insort_right. The old names bisect and insort
1677 are now aliases for bisect_right and insort_right. XXX_right
1678 and XXX_left methods differ in what happens when the new element
1679 compares equal to one or more elements already in the list: the
1680 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001681 right. Code that doesn't care where equal elements end up should
1682 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001683
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001684- The new curses.panel module wraps the panel library that forms part
1685 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1686
Guido van Rossumf61f1662001-01-10 20:13:55 +00001687- The SocketServer module now sets the allow_reuse_address flag by
1688 default in the TCPServer class.
1689
1690- A new function, sys._getframe(), returns the stack frame pointer of
1691 the caller. This is intended only as a building block for
1692 higher-level mechanisms such as string interpolation.
1693
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001694- The pyexpat module supports a number of new handlers, which are
1695 available only in expat 1.2. If invocation of a callback fails, it
1696 will report an additional frame in the traceback. Parser objects
1697 participate now in garbage collection. If expat reports an unknown
1698 encoding, pyexpat will try to use a Python codec; that works only
1699 for single-byte charsets. The parser type objects is exposed as
1700 XMLParserObject.
1701
1702- xml.dom now offers standard definitions for symbolic node type and
1703 exception code constants, and a hierarchy of DOM exceptions. minidom
1704 was adjusted to use them.
1705
1706- The conformance of xml.dom.minidom to the DOM specification was
1707 improved. It detects a number of additional error cases; the
1708 previous/next relationship works even when the tree is modified;
1709 Node supports the normalize() method; NamedNodeMap, DocumentType and
1710 DOMImplementation classes were added; Element supports the
1711 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1712 method.
1713
Guido van Rossumf61f1662001-01-10 20:13:55 +00001714Build issues
1715
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001716- For Unix (and Unix-compatible) builds, configuration and building of
1717 extension modules is now greatly automated. Rather than having to
1718 edit the Modules/Setup file to indicate which modules should be
1719 built and where their include files and libraries are, a
1720 distutils-based setup.py script now takes care of building most
1721 extension modules. All extension modules built this way are built
1722 as shared libraries. Only a few modules that must be linked
1723 statically are still listed in the Setup file; you won't need to
1724 edit their configuration.
1725
1726- Python should now build out of the box on Cygwin. If it doesn't,
1727 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001728
1729- Python now always uses its own (renamed) implementation of getopt()
1730 -- there's too much variation among C library getopt()
1731 implementations.
1732
1733- C++ compilers are better supported; the CXX macro is always set to a
1734 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001735
Tim Petersd92dfe02000-12-12 01:18:41 +00001736Windows changes
1737
1738- select module: By default under Windows, a select() call
1739 can specify no more than 64 sockets. Python now boosts
1740 this Microsoft default to 512. If you need even more than
1741 that, see the MS docs (you'll need to #define FD_SETSIZE
1742 and recompile Python from source).
1743
Guido van Rossumf61f1662001-01-10 20:13:55 +00001744- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1745 subdirectory is no more!
1746
Tim Petersa3a3a032000-11-30 05:22:44 +00001747
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001748What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001749=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001750
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001751Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001752changes are in the file HISTORY. If you are making the jump directly
1753from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1754HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001755
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001756Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1757the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1758http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001759
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001760--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001761
1762======================================================================
1763
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001764What's new in 2.0 (since release candidate 1)?
1765==============================================
1766
1767Standard library
1768
1769- The copy_reg module was modified to clarify its intended use: to
1770 register pickle support for extension types, not for classes.
1771 pickle() will raise a TypeError if it is passed a class.
1772
1773- Fixed a bug in gettext's "normalize and expand" code that prevented
1774 it from finding an existing .mo file.
1775
1776- Restored support for HTTP/0.9 servers in httplib.
1777
Tim Peters989b7b92000-10-16 20:24:53 +00001778- The math module was changed to stop raising OverflowError in case of
1779 underflow, and return 0 instead in underflow cases. Whether Python
1780 used to raise OverflowError in case of underflow was platform-
1781 dependent (it did when the platform math library set errno to ERANGE
1782 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001783
1784- Fixed a bug in StringIO that occurred when the file position was not
1785 at the end of the file and write() was called with enough data to
1786 extend past the end of the file.
1787
1788- Fixed a bug that caused Tkinter error messages to get lost on
1789 Windows. The bug was fixed by replacing direct use of
1790 interp->result with Tcl_GetStringResult(interp).
1791
1792- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1793 redirect response.
1794
1795- Several changes were made to distutils: Some debugging code was
1796 removed from util. Fixed the installer used when an external zip
1797 program (like WinZip) is not found; the source code for this
1798 installer is in Misc/distutils. check_lib() was modified to behave
1799 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1800 test for whether installed modules are on sys.path was changed to
1801 use both normcase() and normpath().
1802
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001803- Several minor bugs were fixed in the xml package (the minidom,
1804 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001805
1806- The regression test driver (regrtest.py) behavior when invoked with
1807 -l changed: It now reports a count of objects that are recognized as
1808 garbage but not freed by the garbage collector.
1809
Tim Peters989b7b92000-10-16 20:24:53 +00001810- The regression test for the math module was changed to test
1811 exceptional behavior when the test is run in verbose mode. Python
1812 cannot yet guarantee consistent exception behavior across platforms,
1813 so the exception part of test_math is run only in verbose mode, and
1814 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001815
1816Internals
1817
1818- PyOS_CheckStack() has been disabled on Win64, where it caused
1819 test_sre to fail.
1820
1821Build issues
1822
1823- Changed compiler flags, so that gcc is always invoked with -Wall and
1824 -Wstrict-prototypes. Users compiling Python with GCC should see
1825 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001826 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001827 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001828
Tim Petersa3a3a032000-11-30 05:22:44 +00001829- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001830
1831Tools and other miscellany
1832
1833- The compiler in Tools/compiler was updated to support the new
1834 language features introduced in 2.0: extended print statement, list
1835 comprehensions, and augmented assignments. The new compiler should
1836 also be backwards compatible with Python 1.5.2; the compiler will
1837 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001838 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001839
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001840What's new in 2.0 release candidate 1 (since beta 2)?
1841=====================================================
1842
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001843What is release candidate 1?
1844
1845We believe that release candidate 1 will fix all known bugs that we
1846intend to fix for the 2.0 final release. This release should be a bit
1847more stable than the previous betas. We would like to see even more
1848widespread testing before the final release, so we are producing this
1849release candidate. The final release will be exactly the same unless
1850any show-stopping (or brown bag) bugs are found by testers of the
1851release candidate.
1852
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001853All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001854to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001855
1856Core language, builtins, and interpreter
1857
1858- A bug that caused crashes when __coerce__ was used with augmented
1859 assignment, e.g. +=, was fixed.
1860
1861- Raise ZeroDivisionError when raising zero to a negative number,
1862 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1863 power operator and the result of math.pow(0.0, -2.0) will vary by
1864 platform. On Linux, it raises a ValueError.
1865
1866- A bug in Unicode string interpolation was fixed that occasionally
1867 caused errors with formats including "%%". For example, the
1868 following expression "%% %s" % u"abc" no longer raises a TypeError.
1869
1870- Compilation of deeply nested expressions raises MemoryError instead
1871 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1872
1873- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1874 rendering them useless. They are now written in binary mode again.
1875
1876Standard library
1877
1878- Keyword arguments are now accepted for most pattern and match object
1879 methods in SRE, the standard regular expression engine.
1880
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001881- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001882 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001883
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001884- Several bugs in the Unicode handling and error handling in _tkinter
1885 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001886
1887- Fix memory management errors in Merge() and Tkapp_Call() routines.
1888
1889- Several changes were made to cStringIO to make it compatible with
1890 the file-like object interface and with StringIO. If operations are
1891 performed on a closed object, an exception is raised. The truncate
1892 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001893 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001894
1895- There were many changes made to the linuxaudiodev module and its
1896 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001897 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001898
1899 Note that this module is named poorly, because it should work
1900 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001901 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001902
1903 The module now raises exceptions when errors occur instead of
1904 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1905 audio) and defines a getptr() method that calls the
1906 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1907
1908- The library_version attribute, introduced in an earlier beta, was
1909 removed because it can not be supported with early versions of the C
1910 readline library, which provides no way to determine the version at
1911 compile-time.
1912
1913- The binascii module is now enabled on Win64.
1914
Tim Peters46446d62000-10-09 21:19:31 +00001915- tokenize.py no longer suffers "recursion depth" errors when parsing
1916 programs with very long string literals.
1917
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001918Internals
1919
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001920- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001921 which is called when the interpreter starts up to determine where
1922 the standard library is installed. These vulnerabilities affect all
1923 previous versions of Python and can be exploited by setting very
1924 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1925 setuid Python script, although use of the wrapper in
1926 Misc/setuid-prog.c will eliminate the vulnerability.
1927
1928- Fixed garbage collection bugs in instance creation that were
1929 triggered when errors occurred during initialization. The solution,
1930 applied in cPickle and in PyInstance_New(), is to call
1931 PyObject_GC_Init() after the initialization of the object's
1932 container attributes is complete.
1933
1934- pyexpat adds definitions of PyModule_AddStringConstant and
1935 PyModule_AddObject if the Python version is less than 2.0, which
1936 provides compatibility with PyXML on Python 1.5.2.
1937
1938- If the platform has a bogus definition for LONG_BIT (the number of
1939 bits in a long), an error will be reported at compile time.
1940
1941- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1942 collection crashes and possibly other, unreported crashes.
1943
1944- Fixed a memory leak in _PyUnicode_Fini().
1945
1946Build issues
1947
1948- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001949 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001950 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001951
1952- The mmap.PAGESIZE constant is now initialized using sysconf when
1953 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1954
1955- The md5 file should now compile on all platforms.
1956
1957- The select module now compiles on platforms that do not define
1958 POLLRDNORM and related constants.
1959
1960- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001961 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001962
Jeremy Hylton10921202000-10-09 18:34:12 +00001963- BeOS: A number of changes were made to the build and installation
1964 process. ar-fake now operates on a directory of object files.
1965 dl_export.h is gone, and its macros now appear on the mwcc command
1966 line during build on PPC BeOS.
1967
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001968- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001969 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001970
1971- Cygwin: Support for shared libraries, Tkinter, and sockets.
1972
1973- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1974
1975Tools and other miscellany
1976
1977- Removed debugging prints from main used with freeze.
1978
Tim Peters46446d62000-10-09 21:19:31 +00001979- IDLE auto-indent no longer crashes when it encounters Unicode
1980 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001981
1982What's new in 2.0 beta 2 (since beta 1)?
1983========================================
1984
1985Core language, builtins, and interpreter
1986
Tim Peters482c0212000-09-26 06:33:09 +00001987- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001988 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001989
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001990- Add -h and -V command line options to print the usage message and
1991 Python version number and exit immediately.
1992
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001993- eval() and exec accept Unicode objects as code parameters.
1994
1995- getattr() and setattr() now also accept Unicode objects for the
1996 attribute name, which are converted to strings using the default
1997 encoding before lookup.
1998
1999- Multiplication on string and Unicode now does proper bounds
2000 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2001 string is too long."
2002
2003- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002004 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002005
Jeremy Hylton1b618592000-09-26 05:32:36 +00002006
2007Standard library and extensions
2008
Guido van Rossum5b08f132001-04-16 02:05:23 +00002009- socket module: the OpenSSL code now adds support for RAND_status()
2010 and EGD (Entropy Gathering Device).
2011
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002012- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002013 argument checking; it still takes no arguments.
2014
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002015- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002016
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002017- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002018
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002019- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020
2021- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002022 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002023
2024- copy: Copy Unicode objects atomically.
2025
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002026- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002027
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002028- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002029
Fred Drake67233bc2000-09-26 16:40:27 +00002030- dbm: Add get() and setdefault() methods to dbm object. Add constant
2031 `library' to module that names the library used. Added doc strings
2032 and method names to error messages. Uses configure to determine
2033 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2034 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002035
2036- distutils: Update to version 0.9.3.
2037
2038- dl: Add several dl.RTLD_ constants.
2039
2040- fpectl: Now supported on FreeBSD.
2041
2042- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2043 found by the collector will be saved in gc.garbage. This is useful
2044 for debugging a program that creates reference cycles.
2045
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002046- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002047 of HTTP class. Do not close socket on zero-length response. Do not
2048 crash when server sends invalid content-length header.
2049
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002050- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002051
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002052- marshal: When reading a short, sign-extend on platforms where shorts
2053 are bigger than 16 bits. When reading a long, repair the unportable
2054 sign extension that was being done for 64-bit machines. (It assumed
2055 that signed right shift sign-extends.)
2056
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002057- operator: Add contains(), invert(), __invert__() as aliases for
2058 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002060- os: Add support for popen2() and popen3() on all platforms where
2061 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002062
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002063- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002064 clicking on a file in Explorer (or passing the file name to the
2065 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002066
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002067- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002068 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002069
2070- pickle: Now raises ValueError when an invalid pickle that contains
2071 a non-string repr where a string repr was expected. This behavior
2072 matches cPickle.
2073
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002074- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002075
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002076- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002077
2078- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002079 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002080 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002081
2082- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002083 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002084
2085- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002086 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002087 few cycles during startup since the first call to
2088 setdefaultencoding() will initialize the codec registry and the
2089 encodings package.
2090
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002091- socket: Support for size hint in readlines() method of object returned
2092 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002093
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002094- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002095 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002096 is followed by whitespace.
2097
Tim Petersa3a3a032000-11-30 05:22:44 +00002098- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002099
2100- struct: Check ranges for bytes and shorts.
2101
2102- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002103 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002104
2105- Tkinter: Image objects are now guaranteed to have unique ids. Set
2106 event.delta to zero if Tk version doesn't support mousewheel.
2107 Removed some debugging prints.
2108
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002109- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002110
Fred Drake67233bc2000-09-26 16:40:27 +00002111- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002112 which works around a bug in Norton AntiVirus 2000 that leads directly
2113 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002114
2115- xml: New version detection code allows PyXML to override standard
2116 XML package if PyXML version is greater than 0.6.1.
2117
Fred Drake64bb3802000-09-26 16:21:35 +00002118- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2119 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2120 tree only for nodes which are sufficiently interesting to a specific
2121 application. Does not provide the HTML-specific extensions. Still
2122 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002123
Fred Drake64bb3802000-09-26 16:21:35 +00002124- xml.sax: SAX 2 support for Python, including all the handler
2125 interfaces needed to process XML 1.0 compliant XML. Some
2126 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002127
Fred Drake64bb3802000-09-26 16:21:35 +00002128- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2129 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002130
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002131
Jeremy Hylton1b618592000-09-26 05:32:36 +00002132C API
2133
2134- Add three new convenience functions for module initialization --
2135 PyModule_AddObject(), PyModule_AddIntConstant(), and
2136 PyModule_AddStringConstant().
2137
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002138- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002139 removed and add #error to Python.h if NULL isn't defined after
2140 #include of stdio.h.
2141
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002142- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002143 backwards compatibility (at the source level) with old extensions.
2144
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002145- A wrapper API was added for signal() and sigaction(). Instead of
2146 either function, always use PyOS_getsig() to get a signal handler
2147 and PyOS_setsig() to set one. A new convenience typedef
2148 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002149
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002150- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002151 internal data buffer and size of a string object -- or the default
2152 encoded version of a Unicode object.
2153
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002154- PyString_Size() and PyString_AsString() accept Unicode objects.
2155
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002156- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002157 exists). INT_MAX and LONG_MAX will always be defined, even if
2158 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002159
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002160- PyFloat_FromString takes a second argument, pend, that was
2161 effectively useless. It is now officially useless but preserved for
2162 backwards compatibility. If the pend argument is not NULL, *pend is
2163 set to NULL.
2164
2165- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2166 for the attribute name. See note on getattr() above.
2167
2168- A few bug fixes to argument processing for Unicode.
2169 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2170 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2171 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002172 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002173
2174- Py_BuildValue accepts B format (for bgen-generated code).
2175
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002176
Jeremy Hylton1b618592000-09-26 05:32:36 +00002177Internals
2178
2179- On Unix, fix code for finding Python installation directory so that
2180 it works when argv[0] is a relative path.
2181
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002182- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002183 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002184 rather than by generating a copy of the object.
2185
Tim Peters482c0212000-09-26 06:33:09 +00002186- Several of the internal Unicode tables are much smaller now, and
2187 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002188
Jeremy Hylton97693b02000-09-26 17:42:51 +00002189- In the garbage collector: Fixed bug in collection of tuples. Fixed
2190 bug that caused some instances to be removed from the container set
2191 while they were still live. Fixed parsing in gc.set_debug() for
2192 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002193
2194- Fixed refcount problem in instance deallocation that only occurred
2195 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2196
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002197- On Windows, getpythonregpath is now protected against null data in
2198 registry key.
2199
2200- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002201 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002202
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002203
Jeremy Hylton1b618592000-09-26 05:32:36 +00002204Build and platform-specific issues
2205
2206- Better support of GNU Pth via --with-pth configure option.
2207
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002208- Python/C API now properly exposed to dynamically-loaded extension
2209 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002210
2211- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2212 Don't define MS_SYNC to be zero when it is undefined. Added missing
2213 prototypes in posixmodule.c.
2214
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002215- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002216 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002217
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002218- Fix largefile support on older NetBSD systems and OpenBSD by adding
2219 define for TELL64.
2220
2221
2222Tools and other miscellany
2223
2224- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2225
2226- freeze: The modulefinder now works with 2.0 opcodes.
2227
Tim Petersa3a3a032000-11-30 05:22:44 +00002228- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002229 Move hackery of sys.argv until after the Tk instance has been
2230 created, which allows the application-specific Tkinter
2231 initialization to be executed if present; also pass an explicit
2232 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002233
Jeremy Hylton1b618592000-09-26 05:32:36 +00002234
2235What's new in 2.0 beta 1?
2236=========================
2237
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002238Source Incompatibilities
2239------------------------
2240
2241None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2242such as single-argument append(), connect() and bind(), and changes to
2243str(long) and repr(float).
2244
2245
2246Binary Incompatibilities
2247------------------------
2248
2249- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2250with Python 2.0; these extensions will have to be rebuilt for Python
22512.0.
2252
2253- On Windows, attempting to import a third party extension built for
2254Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2255can do about this. Check your PYTHONPATH environment variable!
2256
2257- Python bytecode files (*.pyc and *.pyo) are not compatible between
2258releases.
2259
2260
2261Overview of Changes Since 1.6
2262-----------------------------
2263
2264There are many new modules (including brand new XML support through
2265the xml package, and i18n support through the gettext module); a list
2266of all new modules is included below. Lots of bugs have been fixed.
2267
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002268The process for making major new changes to the language has changed
2269since Python 1.6. Enhancements must now be documented by a Python
2270Enhancement Proposal (PEP) before they can be accepted.
2271
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002272There are several important syntax enhancements, described in more
2273detail below:
2274
2275 - Augmented assignment, e.g. x += 1
2276
2277 - List comprehensions, e.g. [x**2 for x in range(10)]
2278
2279 - Extended import statement, e.g. import Module as Name
2280
2281 - Extended print statement, e.g. print >> file, "Hello"
2282
2283Other important changes:
2284
2285 - Optional collection of cyclical garbage
2286
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002287Python Enhancement Proposal (PEP)
2288---------------------------------
2289
2290PEP stands for Python Enhancement Proposal. A PEP is a design
2291document providing information to the Python community, or describing
2292a new feature for Python. The PEP should provide a concise technical
2293specification of the feature and a rationale for the feature.
2294
2295We intend PEPs to be the primary mechanisms for proposing new
2296features, for collecting community input on an issue, and for
2297documenting the design decisions that have gone into Python. The PEP
2298author is responsible for building consensus within the community and
2299documenting dissenting opinions.
2300
2301The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002302
2303Augmented Assignment
2304--------------------
2305
2306This must have been the most-requested feature of the past years!
2307Eleven new assignment operators were added:
2308
Guido van Rossume905e952000-09-05 12:42:46 +00002309 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002310
2311For example,
2312
2313 A += B
2314
2315is similar to
2316
2317 A = A + B
2318
2319except that A is evaluated only once (relevant when A is something
2320like dict[index].attr).
2321
2322However, if A is a mutable object, A may be modified in place. Thus,
2323if A is a number or a string, A += B has the same effect as A = A+B
2324(except A is only evaluated once); but if a is a list, A += B has the
2325same effect as A.extend(B)!
2326
2327Classes and built-in object types can override the new operators in
2328order to implement the in-place behavior; the not-in-place behavior is
2329used automatically as a fallback when an object doesn't implement the
2330in-place behavior. For classes, the method name is derived from the
2331method name for the corresponding not-in-place operator by inserting
2332an 'i' in front of the name, e.g. __iadd__ implements in-place
2333__add__.
2334
2335Augmented assignment was implemented by Thomas Wouters.
2336
2337
2338List Comprehensions
2339-------------------
2340
2341This is a flexible new notation for lists whose elements are computed
2342from another list (or lists). The simplest form is:
2343
2344 [<expression> for <variable> in <sequence>]
2345
Guido van Rossum56db0952000-09-06 23:34:25 +00002346For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002347This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002348
2349You can also add a condition:
2350
2351 [<expression> for <variable> in <sequence> if <condition>]
2352
2353For example, [w for w in words if w == w.lower()] would yield the list
2354of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002355than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002356
2357You can also have nested for loops and more than one 'if' clause. For
2358example, here's a function that flattens a sequence of sequences::
2359
2360 def flatten(seq):
2361 return [x for subseq in seq for x in subseq]
2362
2363 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2364
2365This prints
2366
2367 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2368
2369List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002370Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002371
2372
2373Extended Import Statement
2374-------------------------
2375
2376Many people have asked for a way to import a module under a different
2377name. This can be accomplished like this:
2378
2379 import foo
2380 bar = foo
2381 del foo
2382
2383but this common idiom gets old quickly. A simple extension of the
2384import statement now allows this to be written as follows:
2385
2386 import foo as bar
2387
2388There's also a variant for 'from ... import':
2389
2390 from foo import bar as spam
2391
2392This also works with packages; e.g. you can write this:
2393
2394 import test.regrtest as regrtest
2395
2396Note that 'as' is not a new keyword -- it is recognized only in this
2397context (this is only possible because the syntax for the import
2398statement doesn't involve expressions).
2399
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002400Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002401
2402
2403Extended Print Statement
2404------------------------
2405
2406Easily the most controversial new feature, this extension to the print
2407statement adds an option to make the output go to a different file
2408than the default sys.stdout.
2409
2410For example, to write an error message to sys.stderr, you can now
2411write:
2412
2413 print >> sys.stderr, "Error: bad dog!"
2414
2415As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002416evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002417
2418 print >> None, "Hello world"
2419
2420is equivalent to
2421
2422 print "Hello world"
2423
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002424Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002425
2426
2427Optional Collection of Cyclical Garbage
2428---------------------------------------
2429
2430Python is now equipped with a garbage collector that can hunt down
2431cyclical references between Python objects. It's no replacement for
2432reference counting; in fact, it depends on the reference counts being
2433correct, and decides that a set of objects belong to a cycle if all
2434their reference counts can be accounted for from their references to
2435each other. This devious scheme was first proposed by Eric Tiedemann,
2436and brought to implementation by Neil Schemenauer.
2437
2438There's a module "gc" that lets you control some parameters of the
2439garbage collection. There's also an option to the configure script
2440that lets you enable or disable the garbage collection. In 2.0b1,
2441it's on by default, so that we (hopefully) can collect decent user
2442experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002443performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002444off by default in the final 2.0 release.
2445
2446
2447Smaller Changes
2448---------------
2449
2450A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2451map(None, seq1, seq2, ...) when the sequences have the same length;
2452i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2453the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002454zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002455
2456sys.version_info is a tuple (major, minor, micro, level, serial).
2457
2458Dictionaries have an odd new method, setdefault(key, default).
2459dict.setdefault(key, default) returns dict[key] if it exists; if not,
2460it sets dict[key] to default and returns that value. Thus:
2461
2462 dict.setdefault(key, []).append(item)
2463
2464does the same work as this common idiom:
2465
2466 if not dict.has_key(key):
2467 dict[key] = []
2468 dict[key].append(item)
2469
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002470There are two new variants of SyntaxError that are raised for
2471indentation-related errors: IndentationError and TabError.
2472
2473Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2474escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002475
2476The limits on the size of expressions and file in Python source code
2477have been raised from 2**16 to 2**32. Previous versions of Python
2478were limited because the maximum argument size the Python VM accepted
2479was 2**16. This limited the size of object constructor expressions,
2480e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2481limit was raised thanks to a patch by Charles Waldman that effectively
2482fixes the problem. It is now much more likely that you will be
2483limited by available memory than by an arbitrary limit in Python.
2484
2485The interpreter's maximum recursion depth can be modified by Python
2486programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2487limit is the maximum number of recursive calls that can be made by
2488Python code. The limit exists to prevent infinite recursion from
2489overflowing the C stack and causing a core dump. The default value is
24901000. The maximum safe value for a particular platform can be found
2491by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002492
2493New Modules and Packages
2494------------------------
2495
2496atexit - for registering functions to be called when Python exits.
2497
2498imputil - Greg Stein's alternative API for writing custom import
2499hooks.
2500
2501pyexpat - an interface to the Expat XML parser, contributed by Paul
2502Prescod.
2503
2504xml - a new package with XML support code organized (so far) in three
2505subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2506would fill a volume. There's a special feature whereby a
2507user-installed package named _xmlplus overrides the standard
2508xmlpackage; this is intended to give the XML SIG a hook to distribute
2509backwards-compatible updates to the standard xml package.
2510
2511webbrowser - a platform-independent API to launch a web browser.
2512
2513
Guido van Rossume905e952000-09-05 12:42:46 +00002514Changed Modules
2515---------------
2516
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002517array -- new methods for array objects: count, extend, index, pop, and
2518remove
2519
2520binascii -- new functions b2a_hex and a2b_hex that convert between
2521binary data and its hex representation
2522
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002523calendar -- Many new functions that support features including control
2524over which day of the week is the first day, returning strings instead
2525of printing them. Also new symbolic constants for days of week,
2526e.g. MONDAY, ..., SUNDAY.
2527
2528cgi -- FieldStorage objects have a getvalue method that works like a
2529dictionary's get method and returns the value attribute of the object.
2530
2531ConfigParser -- The parser object has new methods has_option,
2532remove_section, remove_option, set, and write. They allow the module
2533to be used for writing config files as well as reading them.
2534
2535ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002536optionally support the RFC 959 REST command.
2537
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002538gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002539
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002540httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2541the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002542
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002543locale -- implement getdefaultlocale for Win32 and Macintosh
2544
2545marshal -- no longer dumps core when marshaling deeply nested or
2546recursive data structures
2547
2548os -- new functions isatty, seteuid, setegid, setreuid, setregid
2549
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002550os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2551support under Unix.
2552
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002553os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002554
2555os.path -- fix semantics of os.path.commonprefix
2556
2557smtplib -- support for sending very long messages
2558
2559socket -- new function getfqdn()
2560
2561readline -- new functions to read, write and truncate history files.
2562The readline section of the library reference manual contains an
2563example.
2564
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002565select -- add interface to poll system call
2566
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002567shutil -- new copyfileobj function
2568
2569SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2570HTTP server.
2571
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002572Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002573
2574urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002575e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002576
2577whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002578
2579
2580Obsolete Modules
2581----------------
2582
2583None. However note that 1.6 made a whole slew of modules obsolete:
2584stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2585poly, zmod, strop, util, whatsound.
2586
2587
2588Changed, New, Obsolete Tools
2589----------------------------
2590
Tim Peters8b092332000-09-05 20:15:25 +00002591None.
Guido van Rossume905e952000-09-05 12:42:46 +00002592
2593
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002594C-level Changes
2595---------------
2596
2597Several cleanup jobs were carried out throughout the source code.
2598
2599All C code was converted to ANSI C; we got rid of all uses of the
2600Py_PROTO() macro, which makes the header files a lot more readable.
2601
2602Most of the portability hacks were moved to a new header file,
2603pyport.h; several other new header files were added and some old
2604header files were removed, in an attempt to create a more rational set
2605of header files. (Few of these ever need to be included explicitly;
2606they are all included by Python.h.)
2607
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002608Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002609and Win64, especially for the new Intel Itanium processor. Mick also
2610added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002611
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002612The C APIs to return an object's size have been update to consistently
2613use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2614previous versions, the abstract interfaces used PyXXX_Length and the
2615concrete interfaces used PyXXX_Size. The old names,
2616e.g. PyObject_Length, are still available for backwards compatibility
2617at the API level, but are deprecated.
2618
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002619The PyOS_CheckStack function has been implemented on Windows by
2620Fredrik Lundh. It prevents Python from failing with a stack overflow
2621on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002622
2623The GC changes resulted in creation of two new slots on object,
2624tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002625the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002626
2627The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002628C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002629
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002630PyErr_Format has been updated to automatically calculate the size of
2631the buffer needed to hold the formatted result string. This change
2632prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002633
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002634New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002635
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002636PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2637that are the same as their non-Ex counterparts except they take an
2638extra flag argument that tells them to close the file when done.
2639
2640XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002641
Tim Peters8b092332000-09-05 20:15:25 +00002642
2643Windows Changes
2644---------------
2645
2646New popen2/popen3/peopen4 in os module (see Changed Modules above).
2647
2648os.popen is much more usable on Windows 95 and 98. See Microsoft
2649Knowledge Base article Q150956. The Win9x workaround described there
2650is implemented by the new w9xpopen.exe helper in the root of your
2651Python installation. Note that Python uses this internally; it is not
2652a standalone program.
2653
2654Administrator privileges are no longer required to install Python
2655on Windows NT or Windows 2000. If you have administrator privileges,
2656Python's registry info will be written under HKEY_LOCAL_MACHINE.
2657Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002658under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002659uses of Python, but will prevent some advanced uses from working
2660(for example, running a Python script as an NT service, or possibly
2661from CGI).
2662
2663[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2664installer; instead, it installs the needed Tcl/Tk files directly in the
2665Python directory. If you already have a Tcl/Tk installation, this
2666wastes some disk space (about 4 Megs) but avoids problems with
2667conflicting Tcl/Tk installations, and makes it much easier for Python
2668to ensure that Tcl/Tk can find all its files.
2669
2670[This was new in 1.6] The Windows installer now installs by default in
2671\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2672
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002673
2674Updates to the changes between 1.5.2 and 1.6
2675--------------------------------------------
2676
2677The 1.6 NEWS file can't be changed after the release is done, so here
2678is some late-breaking news:
2679
2680New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2681and changes to getlocale() and setlocale().
2682
2683The new module is now enabled per default.
2684
2685It is not true that the encodings codecs cannot be used for normal
2686strings: the string.encode() (which is also present on 8-bit strings
2687!) allows using them for 8-bit strings too, e.g. to convert files from
2688cp1252 (Windows) to latin-1 or vice-versa.
2689
2690Japanese codecs are available from Tamito KAJIYAMA:
2691http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2692
2693
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002694======================================================================