blob: 35d72483a2477d14915a1adf30f2c0f44da9d312 [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
7Core and builtins
8
Walter Dörwald068325e2002-04-15 13:36:47 +00009- A method zfill() was added to str and unicode, that fills a numeric
10 string to the left with zeros. For example,
11 "+123".zfill(6) -> "+00123".
12
Guido van Rossum862fe3c2002-04-15 12:36:47 +000013- Complex numbers supported divmod() and the // and % operators, but
14 these make no sense. Since this was documented, they're being
15 deprecated now.
16
Guido van Rossum49042042002-04-13 00:59:05 +000017- String methods lstrip(), rstrip() and strip() now take an optional
18 argument that specifies the characters to strip. For example,
19 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
20
Guido van Rossumc69343b2002-04-12 19:22:48 +000021- Added a new dict method pop(key). This removes and returns the
22 value corresponding to key. [SF patch #539949]
23
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000024- Changed new-style class instantiation so that when C's __new__
25 method returns something that's not a C instance, its __init__ is
26 not called. [SF bug #537450]
27
Guido van Rossum181e41a2002-04-06 00:23:25 +000028- Fixed super() to work correctly with class methods. [SF bug #535444]
29
Guido van Rossum47834462002-04-04 15:21:33 +000030- A new built-in type, bool, has been added, as well as built-in
31 names for its two values, True and False. Comparisons and sundry
32 other operations that return a truth value have been changed to
33 return a bool instead. Read PEP 285 for an explanantion of why this
34 is backward compatible.
35
Guido van Rossum95b62a62002-03-29 01:07:24 +000036- Fixed two bugs reported as SF #535905: under certain conditions,
37 deallocating a deeply nested structure could cause a segfault in the
38 garbage collector, due to interaction with the "trashcan" code;
39 access to the current frame during destruction of a local variable
40 could access a pointer to freed memory.
41
Neil Schemenauer9d50d132002-03-22 17:06:59 +000042- The optional object allocator has been enabled by default.
43
Guido van Rossum8c842552002-03-14 23:05:54 +000044- If you try to pickle an instance of a class that has __slots__ but
45 doesn't define or override __getstate__, a TypeError is now raised.
46 This is done by adding a bozo __getstate__ to the class that always
47 raises TypeError. (Before, this would appear to be pickled, but the
48 state of the slots would be lost.)
49
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000050- PyErr_Display will provide file and line information for all exceptions
51 that have an attribute print_file_and_line, not just SyntaxErrors.
52
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000053- The UTF-8 codec will now encode and decode Unicode surrogates
54 correctly and without raising exceptions for unpaired ones.
55
Neal Norwitz649b7592002-01-01 19:07:13 +000056- file.xreadlines() now raises a ValueError if the file is closed:
57 Previously, an xreadlines object was returned which would raise
58 a ValueError when the xreadlines.next() method was called.
59
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000060- posix.killpg has been added where available.
61
Neal Norwitz0c766a02002-03-27 13:03:09 +000062- sys.exit() inadvertantly allowed more than one argument.
63 An exception will now be raised if more than one argument is used.
64
Tim Petersaf8446f2001-12-21 21:36:50 +000065Extension modules
66
Martin v. Löwis06a83e92002-04-14 10:19:44 +000067- posix.mknod was added.
68
Martin v. Löwis2e64c342002-03-27 18:49:02 +000069- The locale module now exposes the C library's gettext interface.
70
Tim Petersfbf74f22002-03-14 19:06:01 +000071- A security hole ("double free") was found in zlib-1.1.3, a popular
72 third party compression library used by some Python modules. The
73 hole was quickly plugged in zlib-1.1.4, and the Windows build of
74 Python now ships with zlib-1.1.4.
75
Martin v. Löwis688357e2002-04-08 21:28:20 +000076- pwd, grp, and resource return enhanced tuples now, with symbolic
77 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000078
Martin v. Löwis99866332002-03-01 10:27:01 +000079- array.array is now a type object. A new format character
80 'u' indicates Py_UNICODE arrays. For those, .tounicode and
81 .fromunicode methods are available. Arrays now support __iadd__
82 and __imul__.
83
Neal Norwitze790eae2002-01-01 21:14:12 +000084- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000085 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
86 is called.
87
Tim Petersaf8446f2001-12-21 21:36:50 +000088Library
89
Marc-André Lemburg4179a012002-04-05 12:15:05 +000090- The UTF-16, -LE and -BE now raise a NotImplementedError
91 for all calls to .readline(). Previously, they used to just
92 produce garbage or fail with an encoding error -- UTF-16 is
93 a 2-byte encoding and the C lib's line reading APIs don't
94 work well with these.
95
Martin v. Löwis5c137c22002-03-18 12:44:08 +000096- compileall now supports quiet operation.
97
Martin v. Löwis587c98c2002-03-17 18:37:22 +000098- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
99 connections.
100
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000101- socket module: the SSL support was broken out of the main
102 _socket module C helper and placed into a new _ssl helper
103 which now gets imported by socket.py if available and working.
104
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000105- encodings package: added aliases for all supported IANA character
106 sets
107
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000108- ftplib: to safeguard the user's privacy, anonymous login will use
109 "anonymous@" as default password, rather than the real user and host
110 name.
111
Fred Drake36736122002-01-10 13:50:31 +0000112- webbrowser: tightened up the command passed to os.system() so that
113 arbitrary shell code can't be executed because a bogus URL was
114 passed in.
115
Tim Peters11bd9942002-02-01 00:52:29 +0000116- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000117 gettext.find an optional all argument. Translations will now fallback
118 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000119
Martin v. Löwis9668b932002-01-12 11:27:42 +0000120- distutils bdist commands now offer a --skip-build option.
121
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000122- warnings.warn now accepts a Warning instance as first argument.
123
Fred Drakefed7e852002-04-04 19:36:15 +0000124- The xml.sax.expatreader.ExpatParser class will no longer create
125 circular references by using itself as the locator that gets passed
126 to the content handler implementation. [SF bug #535474]
127
Tim Petersaf8446f2001-12-21 21:36:50 +0000128Tools/Demos
129
Marc-André Lemburg46260092002-04-04 16:17:11 +0000130- freeze.py now produces binaries which can import shared modules,
131 unlike before when this failed due to missing symbol exports in
132 the generated binary.
133
Tim Petersaf8446f2001-12-21 21:36:50 +0000134Build
135
Martin v. Löwis1142de32002-03-29 16:28:31 +0000136- On Unix, a shared libpython2.3.so can be created with --enable-shared.
137
Tim Peters8deda702002-03-30 10:06:07 +0000138- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
139 preprocessor symbols were eliminated. The internal decisions they
140 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000141
Tim Petersaf8446f2001-12-21 21:36:50 +0000142C API
143
Neil Schemenauer9344b142002-04-12 23:00:08 +0000144- The type of tp_free has been changed from "void (*)(PyObject *)" to
145 "void (*)(void *)".
146
147- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
148
Guido van Rossum0986d822002-04-08 01:38:42 +0000149- A type can now inherit its metatype from its base type. Previously,
150 when PyType_Ready() was called, if ob_type was found to be NULL, it
151 was always set to &PyType_Type; now it is set to base->ob_type,
152 where base is tp_base, defaulting to &PyObject_Type.
153
154- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
155
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000156- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
157 functions will be allocated using pymalloc if it is enabled. These
158 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
159 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
160 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
161 PyCore_* family of APIs have been removed.
162
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000163- The "u#" parser marker will now pass through Unicode object as-is
164 without going through the buffer API.
165
Martin v. Löwis7198a522002-01-01 19:59:11 +0000166- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
167
Tim Peters10a3bb52001-12-25 19:07:38 +0000168- An old #define of ANY as void has been removed from pyport.h. This
169 hasn't been used since Python's pre-ANSI days, and the #define has
170 been marked as obsolete since then. SF bug 495548 says it created
171 conflicts with other packages, so keeping it around wasn't harmless.
172
Tim Petersaf8446f2001-12-21 21:36:50 +0000173- Because Python's magic number scheme broke on January 1st, we decided
174 to stop Python development. Thanks for all the fish!
175
Tim Petersfb05db22002-03-11 00:24:00 +0000176- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000177 scheme to a new one. See Python/import.c for details.
178
Tim Petersaf8446f2001-12-21 21:36:50 +0000179New platforms
180
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000181- GNU/Hurd is now supported.
182
Tim Petersaf8446f2001-12-21 21:36:50 +0000183Tests
184
185Windows
186
Tim Peters08e72952002-04-16 20:48:01 +0000187- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
188 of that has been fixed in the installer (disabled Wise's "delete in-
189 use files" uninstall option).
190
Guido van Rossum181e41a2002-04-06 00:23:25 +0000191- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
192
Tim Peters33187922002-04-04 20:02:04 +0000193- The installer now installs Start menu shortcuts under (the local
194 equivalent of) "All Users" when doing an Admin install.
195
Tim Petersfb05db22002-03-11 00:24:00 +0000196- file.truncate([newsize]) now works on Windows for all newsize values.
197 It used to fail if newsize didn't fit in 32 bits, reflecting a
198 limitation of MS _chsize (which is no longer used).
199
Tim Petersab034fa2002-02-01 11:27:43 +0000200- os.waitpid() is now implemented for Windows, and can be used to block
201 until a specified process exits. This is similar to, but not exactly
202 the same as, os.waitpid() on POSIX systems. If you're waiting for
203 a specific process whose pid was obtained from one of the spawn()
204 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000205 See the docs for details. The docs were changed to clarify that
206 spawn functions return, and waitpid requires, a process handle on
207 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000208
Tim Peters11bd9942002-02-01 00:52:29 +0000209- New tempfile.TemporaryFile implementation for Windows: this doesn't
210 need a TemproraryFileWrapper wrapper anymore, and should be immune
211 to a nasty problem: before 2.3, if you got a temp file on Windows, it
212 got wrapped in an object whose close() method first closed the
213 underlying file, then deleted the file. This usually worked fine.
214 However, the spawn family of functions on Windows create (at a low C
215 level) the same set of open files in the spawned process Q as were
216 open in the spawning process P. If a temp file f was among them, then
217 doing f.close() in P first closed P's C-level file handle on f, but Q's
218 C-level file handle on f remained open, so the attempt in P to delete f
219 blew up with a "Permission denied" error (Windows doesn't allow
220 deleting open files). This was surprising, subtle, and difficult to
221 work around.
222
223- The os module now exports all the symbolic constants usable with the
224 low-level os.open() on Windows: the new constants in 2.3 are
225 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
226 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
227 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
228 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
229 (so specify both if you want both; note that neither is useful unless
230 specified with O_CREAT too).
231
Tim Petersaf8446f2001-12-21 21:36:50 +0000232Mac
233
234
Tim Peters909c0912001-12-14 23:16:18 +0000235What's New in Python 2.2 final?
236Release date: 21-Dec-2001
237===============================
238
239Type/class unification and new-style classes
240
Barry Warsaw52acb492001-12-21 20:04:22 +0000241- pickle.py, cPickle: allow pickling instances of new-style classes
242 with a custom metaclass.
243
Tim Peters909c0912001-12-14 23:16:18 +0000244Core and builtins
245
Barry Warsaw52acb492001-12-21 20:04:22 +0000246- weakref proxy object: when comparing, unwrap both arguments if both
247 are proxies.
248
Tim Peters909c0912001-12-14 23:16:18 +0000249Extension modules
250
Barry Warsaw52acb492001-12-21 20:04:22 +0000251- binascii.b2a_base64(): fix a potential buffer overrun when encoding
252 very short strings.
253
254- cPickle: the obscure "fast" mode was suspected of causing stack
255 overflows on the Mac. Hopefully fixed this by setting the recursion
256 limit much smaller. If the limit is too low (it only affects
257 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
258 when compiling cPickle.c (or in pyconfig.h).
259
Tim Peters909c0912001-12-14 23:16:18 +0000260Library
261
Barry Warsaw52acb492001-12-21 20:04:22 +0000262- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
263 close or delete time).
264
265- rfc822.py: fixed a bug where the address '<>' was converted to None
266 instead of an empty string (also fixes the email.Utils module).
267
268- xmlrpclib.py: version 1.0.0; uses precision for doubles.
269
270- test suite: the pickle and cPickle tests were not executing any code
271 when run from the standard regresssion test.
272
Tim Peters909c0912001-12-14 23:16:18 +0000273Tools/Demos
274
275Build
276
277C API
278
279New platforms
280
281Tests
282
283Windows
284
Barry Warsaw52acb492001-12-21 20:04:22 +0000285- distutils package: fixed broken Windows installers (bdist_wininst).
286
287- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
288 instances are deleted at process exit time.
289
290- socket.py: prevent mysterious warnings when socket instances are
291 deleted at process exit time.
292
293- posixmodule.c: fix a Windows crash with stat() of a filename ending
294 in backslash.
295
Tim Peters909c0912001-12-14 23:16:18 +0000296Mac
297
Barry Warsaw52acb492001-12-21 20:04:22 +0000298- The Carbon toolbox modules have been upgraded to Universal Headers
299 3.4, and experimental CoreGraphics and CarbonEvents modules have
300 been added. All only for framework-enabled MacOSX.
301
Tim Peters909c0912001-12-14 23:16:18 +0000302
Tim Peters6272dfd2001-12-13 19:34:00 +0000303What's New in Python 2.2c1?
304Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000305===========================
306
307Type/class unification and new-style classes
308
Barry Warsaw06557452001-12-14 20:47:12 +0000309- Guido's tutorial introduction to the new type/class features has
310 been extensively updated. See
311
312 http://www.python.org/2.2/descrintro.html
313
314 That remains the primary documentation in this area.
315
Guido van Rossum33bab012001-12-05 22:45:48 +0000316- Fixed a leak: instance variables declared with __slots__ were never
317 deleted!
318
Guido van Rossum4b800852001-12-03 00:54:52 +0000319- The "delete attribute" method of descriptor objects is called
320 __delete__, not __del__. In previous releases, it was mistakenly
321 called __del__, which created an unfortunate overloading condition
322 with finalizers. (The "get attribute" and "set attribute" methods
323 are still called __get__ and __set__, respectively.)
324
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000325- Some subtle issues with the super built-in were fixed:
326
327 (a) When super itself is subclassed, its __get__ method would still
328 return an instance of the base class (i.e., of super).
329
330 (b) super(C, C()).__class__ would return C rather than super. This
331 is confusing. To fix this, I decided to change the semantics of
332 super so that it only applies to code attributes, not to data
333 attributes. After all, overriding data attributes is not
334 supported anyway.
335
336 (c) The __get__ method didn't check whether the argument was an
337 instance of the type used in creation of the super instance.
338
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000339- Previously, hash() of an instance of a subclass of a mutable type
340 (list or dictionary) would return some value, rather than raising
341 TypeError. This has been fixed. Also, directly calling
342 dict.__hash__ and list.__hash__ now raises the same TypeError
343 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000344
Guido van Rossumd331cb52001-12-05 19:46:42 +0000345- New-style objects now support deleting their __dict__. This is for
346 all intents and purposes equivalent to assigning a brand new empty
347 dictionary, but saves space if the object is not used further.
348
Tim Petersb3c9af12001-11-17 00:21:57 +0000349Core and builtins
350
Tim Peters3caca232001-12-06 06:23:26 +0000351- -Qnew now works as documented in PEP 238: when -Qnew is passed on
352 the command line, all occurrences of "/" use true division instead
353 of classic division. See the PEP for details. Note that "all"
354 means all instances in library and 3rd-party modules, as well as in
355 your own code. As the PEP says, -Qnew is intended for use only in
356 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000357 Note that test_coercion.py in the standard Python test suite fails
358 under -Qnew; this is expected, and won't be repaired until true
359 division becomes the default (in the meantime, test_coercion is
360 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000361
Fred Drake6c01e252001-12-14 17:08:12 +0000362- complex() now only allows the first argument to be a string
363 argument, and raises TypeError if either the second arg is a string
364 or if the second arg is specified when the first is a string.
365
Tim Petersb3c9af12001-11-17 00:21:57 +0000366Extension modules
367
Martin v. Löwis560da622001-11-24 09:24:51 +0000368- gc.get_referents was renamed to gc.get_referrers.
369
Tim Petersb3c9af12001-11-17 00:21:57 +0000370Library
371
Tim Peters25059d32001-12-07 20:35:43 +0000372- Functions in the os.spawn() family now release the global interpreter
373 lock around calling the platform spawn. They should always have done
374 this, but did not before 2.2c1. Multithreaded programs calling
375 an os.spawn function with P_WAIT will no longer block all Python threads
376 until the spawned program completes. It's possible that some programs
377 relies on blocking, although more likely by accident than by design.
378
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000379- webbrowser defaults to netscape.exe on OS/2 now.
380
Martin v. Löwis652e1912001-11-25 14:50:56 +0000381- Tix.ResizeHandle exposes detach_widget, hide, and show.
382
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000383- The charset alias windows_1252 has been added.
384
Barry Warsaw06557452001-12-14 20:47:12 +0000385- types.StringTypes is a tuple containing the defined string types;
386 usually this will be (str, unicode), but if Python was compiled
387 without Unicode support it will be just (str,).
388
389- The pulldom and minidom modules were synchronized to PyXML.
390
Tim Petersb3c9af12001-11-17 00:21:57 +0000391Tools/Demos
392
Barry Warsaw06557452001-12-14 20:47:12 +0000393- A new script called Tools/scripts/google.py was added, which fires
394 off a search on Google.
395
Tim Petersb3c9af12001-11-17 00:21:57 +0000396Build
397
Barry Warsaw06557452001-12-14 20:47:12 +0000398- Note that release builds of Python should arrange to define the
399 preprocessor symbol NDEBUG on the command line (or equivalent).
400 In the 2.2 pre-release series we tried to define this by magic in
401 Python.h instead, but it proved to cause problems for extension
402 authors. The Unix, Windows and Mac builds now all define NDEBUG in
403 release builds via cmdline (or equivalent) instead. Ports to
404 other platforms should do likewise.
405
Jack Jansen1999ef42001-12-06 21:47:20 +0000406- It is no longer necessary to use --with-suffix when building on a
407 case-insensitive file system (such as Mac OS X HFS+). In the build
408 directory an extension is used, but not in the installed python.
409
Tim Petersb3c9af12001-11-17 00:21:57 +0000410C API
411
Tim Petersf582b822001-12-11 18:51:08 +0000412- New function PyDict_MergeFromSeq2() exposes the builtin dict
413 constructor's logic for updating a dictionary from an iterable object
414 producing key-value pairs.
415
Tim Peterscffed4b2001-11-29 03:26:37 +0000416- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000417 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000418 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
419 dump core in some bad cases. This has been repaired. As a result,
420 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
421 previously went unchallenged.
422
Tim Petersb3c9af12001-11-17 00:21:57 +0000423New platforms
424
425Tests
426
427Windows
428
429Mac
430
Jack Jansenffa260f2001-12-06 21:14:00 +0000431- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
432 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000433
Barry Warsaw06557452001-12-14 20:47:12 +0000434- Changed logic for finding python home in Mac OS X framework Pythons.
435 Now sys.executable points to the executable again, in stead of to
436 the shared library. The latter is used only for locating the python
437 home.
438
439
Tim Peters84362bc2001-10-19 17:55:30 +0000440What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000441Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000442===========================
443
444Type/class unification and new-style classes
445
Guido van Rossum3d27df02001-11-15 20:27:54 +0000446- Multiple inheritance mixing new-style and classic classes in the
447 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000448
449 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000450 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000451
452 The MRO (method resolution order) for each base class is respected
453 according to its kind, but the MRO for the derived class is computed
454 using new-style MRO rules if any base clase is a new-style class.
455 This needs to be documented.
456
Tim Petersa427a2b2001-10-29 22:25:45 +0000457- The new builtin dictionary() constructor, and dictionary type, have
458 been renamed to dict. This reflects a decade of common usage.
459
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000460- dict() now accepts an iterable object producing 2-sequences. For
461 example, dict(d.items()) == d for any dictionary d. The argument,
462 and the elements of the argument, can be any iterable objects.
463
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000464- New-style classes can now have a __del__ method, which is called
465 when the instance is deleted (just like for classic classes).
466
Guido van Rossum12d955c2001-10-26 14:56:06 +0000467- Assignment to object.__dict__ is now possible, for objects that are
468 instances of new-style classes that have a __dict__ (unless the base
469 class forbids it).
470
Guido van Rossumc8e56452001-10-22 00:43:43 +0000471- Methods of built-in types now properly check for keyword arguments
472 (formerly these were silently ignored). The only built-in methods
473 that take keyword arguments are __call__, __init__ and __new__.
474
Guido van Rossum86443212001-10-27 22:28:54 +0000475- The socket function has been converted to a type; see below.
476
Tim Peters84362bc2001-10-19 17:55:30 +0000477Core and builtins
478
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000479- Assignment to __debug__ raises SyntaxError at compile-time. This
480 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000481 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000482
Guido van Rossum12d955c2001-10-26 14:56:06 +0000483- Clarified the error messages for unsupported operands to an operator
484 (like 1 + '').
485
Tim Peters84362bc2001-10-19 17:55:30 +0000486Extension modules
487
Tim Peters5ebfd362001-11-13 23:11:19 +0000488- mmap has a new keyword argument, "access", allowing a uniform way for
489 both Windows and Unix users to create read-only, write-through and
490 copy-on-write memory mappings. This was previously possible only on
491 Unix. A new keyword argument was required to support this in a
492 uniform way because the mmap() signuatures had diverged across
493 platforms. Thanks to Jay T Miller for repairing this!
494
Tim Peters169ded02001-11-03 19:57:21 +0000495- By default, the gc.garbage list now contains only those instances in
496 unreachable cycles that have __del__ methods; in 2.1 it contained all
497 instances in unreachable cycles. "Instances" here has been generalized
498 to include instances of both new-style and old-style classes.
499
Guido van Rossum12d955c2001-10-26 14:56:06 +0000500- The socket module defines a new method for socket objects,
501 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000502 send() until all data has been sent. Also, the socket function has
503 been converted to a subclassable type, like list and tuple (etc.)
504 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000505
506- Various bugfixes to the curses module. There is now a test suite
507 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000508
Guido van Rossum692adf12001-10-30 03:03:03 +0000509- binascii.b2a_base64 no longer places an arbitrary restriction of 57
510 bytes on its input.
511
Tim Peters84362bc2001-10-19 17:55:30 +0000512Library
513
Tim Peters5ebfd362001-11-13 23:11:19 +0000514- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000515 convenience function.
516
Tim Peters75335872001-11-03 19:35:43 +0000517- Symbolic group names in regular expressions must be unique. For
518 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
519 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000520 Python 2.2 detects this error at regexp compilation time;
521 previously, the error went undetected, and results were
522 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
523 pattern.subn() methods have been rewritten in C. Also, an
524 experimental function/method finditer() has been added, which works
525 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000526
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000527- Tix exposes more commands through the classes DirSelectBox,
528 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
529 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
530 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
531
Tim Peters98791af2001-10-23 01:59:54 +0000532- Traceback objects are now scanned by cyclic garbage collection, so
533 cycles created by casual use of sys.exc_info() no longer cause
534 permanent memory leaks (provided garbage collection is enabled).
535
Guido van Rossum49192142001-10-24 20:51:44 +0000536- os.extsep -- a new variable needed by the RISCOS support. It is the
537 separator used by extensions, and is '.' on all platforms except
538 RISCOS, where it is '/'. There is no need to use this variable
539 unless you have a masochistic desire to port your code to RISCOS.
540
Barry Warsaw012852b2001-11-16 16:17:27 +0000541- mimetypes.py has optional support for non-standard, but commonly
542 found types. guess_type() and guess_extension() now accept an
543 optional `strict' flag, defaulting to true, which controls whether
544 recognize non-standard types or not. A few non-standard types we
545 know about have been added. Also, when run as a script, there are
546 new -l and -e options.
547
548- statcache is now deprecated.
549
550- email.Utils.formatdate() now produces the preferred RFC 2822 style
551 dates with numeric timezones (it used to produce obsolete dates
552 hard coded to "GMT" timezone). An optional `localtime' flag is
553 added to produce dates in the local timezone, with daylight savings
554 time properly taken into account.
555
556- In pickle and cPickle, instead of masking errors in load() by
557 transforming them into SystemError, we let the original exception
558 propagate out. Also, implement support for __safe_for_unpickling__
559 in pickle, as it already was supported in cPickle.
560
Tim Peters84362bc2001-10-19 17:55:30 +0000561Tools/Demos
562
563Build
564
Barry Warsaw012852b2001-11-16 16:17:27 +0000565- The dbm module is built using libdb1 if available. The bsddb module
566 is built with libdb3 if available.
567
568- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
569
Tim Peters84362bc2001-10-19 17:55:30 +0000570C API
571
Tim Peters1fc240e2001-10-26 05:06:50 +0000572- New function PySequence_Fast_GET_SIZE() returns the size of a non-
573 NULL result from PySequence_Fast(), more quickly than calling
574 PySequence_Size().
575
Barry Warsaw012852b2001-11-16 16:17:27 +0000576- New argument unpacking function PyArg_UnpackTuple() added.
577
578- New functions PyObject_CallFunctionObjArgs() and
579 PyObject_CallMethodObjArgs() have been added to make it more
580 convenient and efficient to call functions and methods from C.
581
582- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
583 possible that this will propagate errors it didn't before.
584
585- New function PyObject_CheckReadBuffer(), which returns true if its
586 argument supports the single-segment readable buffer interface.
587
Tim Peters84362bc2001-10-19 17:55:30 +0000588New platforms
589
Guido van Rossum86443212001-10-27 22:28:54 +0000590- We've finally confirmed that this release builds on HP-UX 11.00,
591 *with* threads, and passes the test suite.
592
Tim Peters7a33d8b2001-11-05 02:51:07 +0000593- Thanks to a series of patches from Michael Muller, Python may build
594 again under OS/2 Visual Age C++.
595
Guido van Rossum49192142001-10-24 20:51:44 +0000596- Updated RISCOS port by Dietmar Schwertberger.
597
Tim Peters84362bc2001-10-19 17:55:30 +0000598Tests
599
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000600- Added a test script for the curses module. It isn't run automatically;
601 regrtest.py must be run with '-u curses' to enable it.
602
Tim Peters84362bc2001-10-19 17:55:30 +0000603Windows
604
Barry Warsaw012852b2001-11-16 16:17:27 +0000605Mac
606
607- PythonScript has been moved to unsupported and is slated to be
608 removed completely in the next release.
609
610- It should now be possible to build applets that work on both OS9 and
611 OSX.
612
613- The core is now linked with CoreServices not Carbon; as a side
614 result, default 8bit encoding on OSX is now ASCII.
615
616- Python should now build on OSX 10.1.1
617
Tim Peters84362bc2001-10-19 17:55:30 +0000618
Tim Petersabf925f2001-09-28 21:53:42 +0000619What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000620Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000621===========================
622
623Type/class unification and new-style classes
624
Guido van Rossum687ae002001-10-15 22:03:32 +0000625- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000626 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000627 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000628 remains: the __dict__ of a new-style class is a read-only proxy; you
629 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000630 __defined__ attribute of new-style types no longer exists, for lack
631 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000632 future a __cache__ may be resurrected with a similar function, if I
633 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000634
Tim Peters1c9ca872001-10-04 06:43:12 +0000635- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
636 always returned None, even when there was a class docstring).
637
638- doctest now finds and runs docstrings attached to new-style classes,
639 class methods, static methods, and properties.
640
Guido van Rossum9074ef62001-10-16 21:34:49 +0000641Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000642
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000643- A very subtle syntactical pitfall in list comprehensions was fixed.
644 For example: [a+b for a in 'abc', for b in 'def']. The comma in
645 this example is a mistake. Previously, this would silently let 'a'
646 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
647 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
648 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
649 Note that [a for a in <singleton>] is a convoluted way to say
650 [<singleton>] anyway, so it's not like any expressiveness is lost.
651
Guido van Rossum9074ef62001-10-16 21:34:49 +0000652- getattr(obj, name, default) now only catches AttributeError, as
653 documented, rather than returning the default value for all
654 exceptions (which could mask bugs in a __getattr__ hook, for
655 example).
656
Fred Drakecb7a6b52001-10-22 18:41:51 +0000657- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000658 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000659 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000660 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000661
Guido van Rossum1c486092001-10-19 02:05:35 +0000662- unicode(obj) now behaves more like str(obj), accepting arbitrary
663 objects, and calling a __unicode__ method if it exists.
664 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000665 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000666
Barry Warsawf6fb1712001-10-19 05:35:40 +0000667- isinstance() now allows any object as the first argument and a
668 class, a type or something with a __bases__ tuple attribute for the
669 second argument. The second argument may also be a tuple of a
670 class, type, or something with __bases__, in which case isinstance()
671 will return true if the first argument is an instance of any of the
672 things contained in the second argument tuple. E.g.
673
674 isinstance(x, (A, B))
675
676 returns true if x is an instance of A or B.
677
Guido van Rossum9074ef62001-10-16 21:34:49 +0000678Extension modules
679
680- thread.start_new_thread() now returns the thread ID (previously None).
681
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000682- binascii has now two quopri support functions, a2b_qp and b2a_qp.
683
Guido van Rossumc524d952001-10-19 01:31:59 +0000684- readline now supports setting the startup_hook and the
685 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000686
Guido van Rossumc524d952001-10-19 01:31:59 +0000687- os and posix supports chroot(), setgroups() and unsetenv() where
688 available. The stat(), fstat(), statvfs() and fstatvfs() functions
689 now return "pseudo-sequences" -- the various fields can now be
690 accessed as attributes (e.g. os.stat("/").st_mtime) but for
691 backwards compatibility they also behave as a fixed-length sequence.
692 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000693 attributes.
694
695- time: localtime(), gmtime() and strptime() now return a
696 pseudo-sequence similar to the os.stat() return value, with
697 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000698
Guido van Rossum9074ef62001-10-16 21:34:49 +0000699- Decompression objects in the zlib module now accept an optional
700 second parameter to decompress() that specifies the maximum amount
701 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000702
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000703- optional SSL support in the socket module now exports OpenSSL
704 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
705 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000706 automatically seed its PRNG. Also, the keyfile and certfile
707 arguments to socket.ssl() are now optional.
708
709- posixmodule (and by extension, the os module on POSIX platforms) now
710 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000711
Guido van Rossum9074ef62001-10-16 21:34:49 +0000712Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000713
Tim Peters7402f792001-10-02 03:53:41 +0000714- doctest now excludes functions and classes not defined by the module
715 being tested, thanks to Tim Hochberg.
716
Fred Drakecb7a6b52001-10-22 18:41:51 +0000717- HotShot, a new profiler implemented using a C-based callback, has
718 been added. This substantially reduces the overhead of profiling,
719 but it is still quite preliminary. Support modules and
720 documentation will be added in upcoming releases (before 2.2 final).
721
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000722- profile now produces correct output in situations where an exception
723 raised in Python is cleared by C code (e.g. hasattr()). This used
724 to cause wrong output, including spurious claims of recursive
725 functions and attribution of time spent to the wrong function.
726
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000727 The code and documentation for the derived OldProfile and HotProfile
728 profiling classes was removed. The code hasn't worked for years (if
729 you tried to use them, they raised exceptions). OldProfile
730 intended to reproduce the behavior of the profiler Python used more
731 than 7 years ago, and isn't interesting anymore. HotProfile intended
732 to provide a faster profiler (but producing less information), and
733 that's a worthy goal we intend to meet via a different approach (but
734 without losing information).
735
Tim Peterscce092d2001-10-09 05:31:56 +0000736- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000737 a much better system-specific calibration constant. The constant can
738 now be specified in an instance constructor, or as a Profile class or
739 instance variable, instead of by editing profile.py's source code.
740 Calibration must still be done manually (see the docs for the profile
741 module).
742
743 Note that Profile.calibrate() must be overriden by subclasses.
744 Improving the accuracy required exploiting detailed knowledge of
745 profiler internals; the earlier method abstracted away the details
746 and measured a simplified model instead, but consequently computed
747 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000748
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000749- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000750 which indicates whether output is intended for the header 'Q'
751 encoding.
752
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000753- The SocketServer.ThreadingMixIn class now closes the request after
754 finish_request() returns. (Not when it errors out though.)
755
Barry Warsawf6fb1712001-10-19 05:35:40 +0000756- The nntplib module's NNTP.body() method has grown a `file' argument
757 to allow saving the message body to a file.
758
759- The email package has added a class email.Parser.HeaderParser which
760 only parses headers and does not recurse into the message's body.
761 Also, the module/class MIMEAudio has been added for representing
762 audio data (contributed by Anthony Baxter).
763
764- ftplib should be able to handle files > 2GB.
765
766- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
767 ON, and OFF.
768
Fred Drakecb7a6b52001-10-22 18:41:51 +0000769- xml.dom.minidom NodeList objects now support the length attribute
770 and item() method as required by the DOM specifications.
771
Guido van Rossumed554f62001-10-02 23:15:37 +0000772Tools/Demos
773
774- Demo/dns was removed. It no longer serves any purpose; a package
775 derived from it is now maintained by Anthony Baxter, see
776 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000777
Barry Warsawf6fb1712001-10-19 05:35:40 +0000778- The freeze tool has been made more robust, and two new options have
779 been added: -X and -E.
780
Tim Petersabf925f2001-09-28 21:53:42 +0000781Build
782
Barry Warsawf6fb1712001-10-19 05:35:40 +0000783- configure will use CXX in LINKCC if CXX is used to build main() and
784 the system requires to link a C++ main using the C++ compiler.
785
Tim Petersabf925f2001-09-28 21:53:42 +0000786C API
787
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000788- The documentation for the tp_compare slot is updated to require that
789 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
790 not correct. This is not yet enforced but will be enforced in
791 Python 2.3; even later, we may use -2 to indicate errors and +2 for
792 "NotImplemented". Right now, -1 should be used for an error return.
793
Tim Petersd38b1c72001-09-30 05:09:37 +0000794- PyLong_AsLongLong() now accepts int (as well as long) arguments.
795 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
796 as long) arguments.
797
Guido van Rossum3c288632001-10-16 21:13:49 +0000798- PyThread_start_new_thread() now returns a long int giving the thread
799 ID, if one can be calculated; it returns -1 for error, 0 if no
800 thread ID is calculated (this is an incompatible change, but only
801 the thread module used this API). This code has only really been
802 tested on Linux and Windows; other platforms please beware (and
803 report any bugs or strange behavior).
804
Guido van Rossum1c486092001-10-19 02:05:35 +0000805- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
806 input.
807
Tim Petersabf925f2001-09-28 21:53:42 +0000808New platforms
809
810Tests
811
812Windows
813
Tim Peters04cf1d32001-10-09 22:39:40 +0000814- Installer: If you install IDLE, and don't disable file-extension
815 registration, a new "Edit with IDLE" context (right-click) menu entry
816 is created for .py and .pyw files.
817
Tim Peters1ce3cf72001-10-01 17:58:40 +0000818- The signal module now supports SIGBREAK on Windows, thanks to Steven
819 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
820 action remains to call Win32 ExitProcess(). This can be changed via
821 signal.signal(). For example:
822
823 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
824 # (SIGINT) behavior.
825 import signal
826 signal.signal(signal.SIGBREAK,
827 signal.default_int_handler)
828
829 try:
830 while 1:
831 pass
832 except KeyboardInterrupt:
833 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
834 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
835 # program without the possibility for any Python-level cleanup).
836 print "Clean exit"
837
Tim Petersabf925f2001-09-28 21:53:42 +0000838
Tim Petersb07352e2001-09-08 01:25:47 +0000839What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000840Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000841===========================
842
Guido van Rossum808eea72001-09-25 04:15:41 +0000843Type/class unification and new-style classes
844
845- pydoc and inspect are now aware of new-style classes;
846 e.g. help(list) at the interactive prompt now shows proper
847 documentation for all operations on list objects.
848
849- Applications using Jim Fulton's ExtensionClass module can now safely
850 be used with Python 2.2. In particular, Zope 2.4.1 now works with
851 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
852 examples also work again. It is hoped that Gtk and Boost also work
853 with 2.2a4 and beyond. (If you can confirm this, please write
854 webmaster@python.org; if there are still problems, please open a bug
855 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000856
Tim Peters66c1a522001-09-24 21:17:50 +0000857- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
858 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
859 in the constructed property object. fget, fset and fdel weren't
860 discoverable from Python in 2.2a3. __doc__ is new, and allows to
861 associate a docstring with a property.
862
Guido van Rossum808eea72001-09-25 04:15:41 +0000863- Comparison overloading is now more completely implemented. For
864 example, a str subclass instance can properly be compared to a str
865 instance, and it can properly overload comparison. Ditto for most
866 other built-in object types.
867
868- The repr() of new-style classes has changed; instead of <type
869 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
870 *except* for built-in types, which are still rendered as <type
871 'Foo'> (to avoid upsetting existing code that might parse or
872 otherwise rely on repr() of certain type objects).
873
874- The repr() of new-style objects is now always <Foo object at XXX>;
875 previously, it was sometimes <Foo instance at XXX>.
876
877- For new-style classes, what was previously called __getattr__ is now
878 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000879 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000880 one in classic classes is defined which is called only if regular
881 attribute access raises AttributeError; to catch *all* attribute
882 access, you can use __getattribute__ (for new-style classes). If
883 both are defined, __getattribute__ is called first, and if it raises
884 AttributeError, __getattr__ is called.
885
886- The __class__ attribute of new-style objects can be assigned to.
887 The new class must have the same C-level object layout as the old
888 class.
889
890- The builtin file type can be subclassed now. In the usual pattern,
891 "file" is the name of the builtin type, and file() is a new builtin
892 constructor, with the same signature as the builtin open() function.
893 file() is now the preferred way to open a file.
894
895- Previously, __new__ would only see sequential arguments passed to
896 the type in a constructor call; __init__ would see both sequential
897 and keyword arguments. This made no sense whatsoever any more, so
898 now both __new__ and __init__ see all arguments.
899
900- Previously, hash() applied to an instance of a subclass of str or
901 unicode always returned 0. This has been repaired.
902
903- Previously, an operation on an instance of a subclass of an
904 immutable type (int, long, float, complex, tuple, str, unicode),
905 where the subtype didn't override the operation (and so the
906 operation was handled by the builtin type), could return that
907 instance instead a value of the base type. For example, if s was of
908 a str sublass type, s[:] returned s as-is. Now it returns a str
909 with the same value as s.
910
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000911- Provisional support for pickling new-style objects has been added.
912
Guido van Rossum808eea72001-09-25 04:15:41 +0000913Core
914
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000915- file.writelines() now accepts any iterable object producing strings.
916
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000917- PyUnicode_FromEncodedObject() now works very much like
918 PyObject_Str(obj) in that it tries to use __str__/tp_str
919 on the object if the object is not a string or buffer. This
920 makes unicode() behave like str() when applied to non-string/buffer
921 objects.
922
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000923- PyFile_WriteObject now passes Unicode objects to the file's write
924 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000925 of a print statement must support Unicode objects, i.e. they must
926 at least convert them into ASCII strings.
927
Guido van Rossum624c8af2001-09-18 15:21:04 +0000928- Thread scheduling on Solaris should be improved; it is no longer
929 necessary to insert a small sleep at the start of a thread in order
930 to let other runnable threads be scheduled.
931
Tim Petersb07352e2001-09-08 01:25:47 +0000932Library
933
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000934- StringIO.StringIO instances and cStringIO.StringIO instances support
935 read character buffer compatible objects for their .write() methods.
936 These objects are converted to strings and then handled as such
937 by the instances.
938
Barry Warsaw2f600732001-09-24 04:28:10 +0000939- The "email" package has been added. This is basically a port of the
940 mimelib package <http://sf.net/projects/mimelib> with API changes
941 and some implementations updated to use iterators and generators.
942
Tim Peters8a9c2842001-09-22 21:30:22 +0000943- difflib.ndiff() and difflib.Differ.compare() are generators now. This
944 restores the ability of Tools/scripts/ndiff.py to start producing output
945 before the entire comparison is complete.
946
Barry Warsaw58b072d2001-09-22 04:44:21 +0000947- StringIO.StringIO instances and cStringIO.StringIO instances support
948 iteration just like file objects (i.e. their .readline() method is
949 called for each iteration until it returns an empty string).
950
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000951- The codecs module has grown four new helper APIs to access
952 builtin codecs: getencoder(), getdecoder(), getreader(),
953 getwriter().
954
Guido van Rossum624c8af2001-09-18 15:21:04 +0000955- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
956 simplifies writing XML RPC servers.
957
Barry Warsaw647d5e82001-09-28 17:01:02 +0000958- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000959 after interpretation of symbolic links. On non-Unix systems, this
960 is an alias for os.path.abspath().
961
Tim Peters16a77ad2001-09-08 04:00:12 +0000962- operator.indexOf() (PySequence_Index() in the C API) now works with any
963 iterable object.
964
Guido van Rossum624c8af2001-09-18 15:21:04 +0000965- smtplib now supports various authentication and security features of
966 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000967
Guido van Rossum624c8af2001-09-18 15:21:04 +0000968- hmac: a new module implementing keyed hashing for message
969 authentication.
970
971- mimetypes now recognizes more extensions and file types. At the
972 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000973
Guido van Rossum624c8af2001-09-18 15:21:04 +0000974- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000975 Python 2.2 bytecode generation. It has also been promoted from a
976 Tool to a standard library package. (Tools/compiler still exists as
977 a sample driver.)
978
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000979Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000980
Tim Petersb07352e2001-09-08 01:25:47 +0000981Build
982
Guido van Rossum624c8af2001-09-18 15:21:04 +0000983- Large file support (LFS) is now automatic when the platform supports
984 it; no more manual configuration tweaks are needed. On Linux, at
985 least, it's possible to have a system whose C library supports large
986 files but whose kernel doesn't; in this case, large file support is
987 still enabled but doesn't do you any good unless you upgrade your
988 kernel or share your Python executable with another system whose
989 kernel has large file support.
990
991- The configure script now supplies plausible defaults in a
992 cross-compilation environment. This doesn't mean that the supplied
993 values are always correct, or that cross-compilation now works
994 flawlessly -- but it's a first step (and it shuts up most of
995 autoconf's warnings about AC_TRY_RUN).
996
997- The Unix build is now a bit less chatty, courtesy of the parser
998 generator. The build is completely silent (except for errors) when
999 using "make -s", thanks to a -q option to setup.py.
1000
Tim Petersb07352e2001-09-08 01:25:47 +00001001C API
1002
Guido van Rossum624c8af2001-09-18 15:21:04 +00001003- The "structmember" API now supports some new flag bits to deny read
1004 and/or write access to attributes in restricted execution mode.
1005
Tim Petersb07352e2001-09-08 01:25:47 +00001006New platforms
1007
Guido van Rossum624c8af2001-09-18 15:21:04 +00001008- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1009 (http://familiar.handhelds.org).
1010
Tim Petersb07352e2001-09-08 01:25:47 +00001011Tests
1012
Tim Peters8a9c2842001-09-22 21:30:22 +00001013- The "classic" standard tests, which work by comparing stdout to
1014 an expected-output file under Lib/test/output/, no longer stop at
1015 the first mismatch. Instead the test is run to completion, and a
1016 variant of ndiff-style comparison is used to report all differences.
1017 This is much easier to understand than the previous style of reporting.
1018
1019- The unittest-based standard tests now use regrtest's test_main()
1020 convention, instead of running as a side-effect of merely being
1021 imported. This allows these tests to be run in more natural and
1022 flexible ways as unittests, outside the regrtest framework.
1023
1024- regrtest.py is much better integrated with unittest and doctest now,
1025 especially in regard to reporting errors.
1026
Tim Petersb07352e2001-09-08 01:25:47 +00001027Windows
1028
Guido van Rossum624c8af2001-09-18 15:21:04 +00001029- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001030 that support it (NTFS under Windows 2000). See "What's New in
1031 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001032
Tim Petersb07352e2001-09-08 01:25:47 +00001033
Tim Petersedc99312001-08-22 21:36:50 +00001034What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001035Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001036===========================
1037
1038Core
1039
Tim Peters9fffa3e2001-09-04 05:14:19 +00001040- Conversion of long to float now raises OverflowError if the long is too
1041 big to represent as a C double.
1042
Tim Peters32f453e2001-09-03 08:35:41 +00001043- The 3-argument builtin pow() no longer allows a third non-None argument
1044 if either of the first two arguments is a float, or if both are of
1045 integer types and the second argument is negative (in which latter case
1046 the arguments are converted to float, so this is really the same
1047 restriction).
1048
Tim Peters5d2b77c2001-09-03 05:47:38 +00001049- The builtin dir() now returns more information, and sometimes much
1050 more, generally naming all attributes of an object, and all attributes
1051 reachable from the object via its class, and from its class's base
1052 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1053 an empty list. In 2.2a3,
1054
1055 >>> dir([])
1056 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1057 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1058 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1059 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1060 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1061 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1062 'reverse', 'sort']
1063
1064 dir(module) continues to return only the module's attributes, though.
1065
Tim Petersbdee63f2001-09-02 03:40:59 +00001066- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001067 than raising OverflowError. This is a partial implementation of PEP
1068 237. You can use -Wdefault::OverflowWarning to enable a warning for
1069 this situation, and -Werror::OverflowWarning to revert to the old
1070 OverflowError exception.
1071
Guido van Rossum61c345f2001-09-04 03:26:15 +00001072- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001073 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001074 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1075 -Qold, meaning the / operator has its classic meaning and no
1076 warnings are issued. Using -Qwarn issues a run-time warning about
1077 all uses of classic division for int and long arguments; -Qwarnall
1078 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001079 (for use with fixdiv.py).
1080 [Note: the remainder of this paragraph (preserved below) became
1081 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1082 <obsolete>
1083 Using -Qnew is questionable; it turns on new division by default, but
1084 only in the __main__ module. You can usefully combine -Qwarn or
1085 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1086 warns about classic division everywhere else.
1087 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001088
Tim Petersbdee63f2001-09-02 03:40:59 +00001089- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001090 long, float, str, unicode, and tuple. (The types complex, list and
1091 dictionary can also be subclassed; this was introduced earlier.)
1092 Note that restrictions apply when subclassing immutable built-in
1093 types: you can only affect the value of the instance by overloading
1094 __new__. You can add mutable attributes, and the subclass instances
1095 will have a __dict__ attribute, but you cannot change the "value"
1096 (as implemented by the base class) of an immutable subclass instance
1097 once it is created.
1098
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001099- The dictionary constructor now takes an optional argument, a
1100 mapping-like object, and initializes the dictionary from its
1101 (key, value) pairs.
1102
Tim Petersbdee63f2001-09-02 03:40:59 +00001103- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001104 "cooperative super calls" in a multiple inheritance setting. For an
1105 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1106
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001107- A new built-in type, property, has been added. This enables the
1108 creation of "properties". These are attributes implemented by
1109 getter and setter functions (or only one of these for read-only or
1110 write-only attributes), without the need to override __getattr__.
1111 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001112
Tim Petersbdee63f2001-09-02 03:40:59 +00001113- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001114 liberalized, to allow leading zeroes. Examples of literals now
1115 legal that were SyntaxErrors before:
1116
1117 00.0 0e3 0100j 07.5 00000000000000000008.
1118
Tim Petersbdee63f2001-09-02 03:40:59 +00001119- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001120 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1121
Tim Petersedc99312001-08-22 21:36:50 +00001122Library
1123
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001124- telnetlib includes symbolic names for the options, and support for
1125 setting an option negotiation callback.
1126
Tim Petersa40c7932001-09-05 22:36:56 +00001127- The new C standard no longer requires that math libraries set errno to
1128 ERANGE on overflow. For platform libraries that exploit this new
1129 freedom, Python's overflow-checking was wholly broken. A new overflow-
1130 checking scheme attempts to repair that, but may not be reliable on all
1131 platforms (C doesn't seem to provide anything both useful and portable
1132 in this area anymore).
1133
Martin v. Löwis44f86962001-09-05 13:44:54 +00001134- Asynchronous timeout actions are available through the new class
1135 threading.Timer.
1136
Tim Peters78526162001-09-05 00:53:45 +00001137- math.log and math.log10 now return sensible results for even huge
1138 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1139
Tim Petersbdee63f2001-09-02 03:40:59 +00001140- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001141 currently held. See the docs for the imp module.
1142
Tim Petersbdee63f2001-09-02 03:40:59 +00001143- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001144 dumps containing ints written on platforms where Python ints are 8 bytes.
1145 When read on a box where Python ints are 4 bytes, such values are
1146 converted to Python longs.
1147
Tim Petersbdee63f2001-09-02 03:40:59 +00001148- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001149 code objects is no longer allowed. This plugs a security hole.
1150
Steve Purcell6091cd62001-09-06 16:05:17 +00001151- unittest.TestResult instances no longer store references to tracebacks
1152 generated by test failures. This prevents unexpected dangling references
1153 to objects that should be garbage collected between tests.
1154
Tim Petersedc99312001-08-22 21:36:50 +00001155Tools
1156
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001157- Tools/scripts/fixdiv.py has been added which can be used to fix
1158 division operators as per PEP 238.
1159
Tim Petersedc99312001-08-22 21:36:50 +00001160Build
1161
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001162- If you are an adventurous person using Mac OS X you may want to look at
1163 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1164 application, which can be used for experimenting with Carbon or Cocoa.
1165 Discussion of this on pythonmac-sig, please.
1166
Tim Peters7eea37e2001-09-04 22:08:56 +00001167C API
1168
1169- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001170
Tim Peters9fffa3e2001-09-04 05:14:19 +00001171- Note that PyLong_AsDouble can fail! This has always been true, but no
1172 callers checked for it. It's more likely to fail now, because overflow
1173 errors are properly detected now. The proper way to check:
1174
1175 double x = PyLong_AsDouble(some_long_object);
1176 if (x == -1.0 && PyErr_Occurred()) {
1177 /* The conversion failed. */
1178 }
1179
Tim Petersbdee63f2001-09-02 03:40:59 +00001180- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001181 compile but will not participate in GC. To upgrade an extension
1182 module:
1183
1184 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001185
Neil Schemenauer4042c692001-08-30 15:38:01 +00001186 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1187 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001188
Neil Schemenauer4042c692001-08-30 15:38:01 +00001189 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1190 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001191
Neil Schemenauer4042c692001-08-30 15:38:01 +00001192 - remove PyGC_HEAD_SIZE from object size calculations
1193
1194 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1195
Tim Petersbdee63f2001-09-02 03:40:59 +00001196- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001197 These can be used safely to construct string objects from a
1198 sprintf-style format string (similar to the format string supported
1199 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001200
Tim Petersedc99312001-08-22 21:36:50 +00001201New platforms
1202
Tim Petersb7da0902001-09-02 23:01:43 +00001203- Stephen Hansen contributed patches sufficient to get a clean compile
1204 under Borland C (Windows), but he reports problems running it and ran
1205 out of time to complete the port. Volunteers? Expect a MemoryError
1206 when importing the types module; this is probably shallow, and
1207 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001208
Tim Petersedc99312001-08-22 21:36:50 +00001209Tests
1210
1211Windows
1212
Tim Peters6e13a562001-09-06 00:32:15 +00001213- Large file support is now enabled on Win32 platforms as well as on
1214 Win64. This means that, for example, you can use f.tell() and f.seek()
1215 to manipulate files larger than 2 gigabytes (provided you have enough
1216 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001217 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1218 filesize limit, and large file support makes no difference there.
1219 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1220 NTFS has no practical limit on file size, and files of any size can be
1221 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001222
Tim Petersbdee63f2001-09-02 03:40:59 +00001223- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001224 points to command.com (patch from Brian Quinlan).
1225
Tim Petersedc99312001-08-22 21:36:50 +00001226
Tim Peters20f51a72001-07-21 02:31:40 +00001227What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001228Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001229===========================
1230
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001231Build
1232
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001233- Tim Peters developed a brand new Windows installer using Wise 8.1,
1234 generously donated to us by Wise Solutions.
1235
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001236- configure supports a new option --enable-unicode, with the values
1237 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1238 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001239
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001240- A new configure option --enable-framework builds a Mac OS X framework,
1241 which "make frameworkinstall" will install. This provides a starting
1242 point for more mac-like functionality, join pythonmac-sig@python.org
1243 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001244
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001245- The NeXT platform is no longer supported.
1246
1247- The `new' module is now statically linked.
1248
Tim Peters0afb6092001-08-15 06:06:44 +00001249Tools
1250
1251- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001252 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001253 the module docstring for details.
1254
Tim Peters20f51a72001-07-21 02:31:40 +00001255Tests
1256
Tim Peters5e824c32001-08-12 22:25:01 +00001257- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001258 platforms, allowing to give clearer test result output. regrtest
1259 also has optional --use/-u switch to run normally disabled tests
1260 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001261
Tim Peters20f51a72001-07-21 02:31:40 +00001262- Several new tests in the standard test suite, with special thanks to
1263 Nick Mathewson.
1264
1265Core
1266
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001267- The floor division operator // has been added as outlined in PEP
1268 238. The / operator still provides classic division (and will until
1269 Python 3.0) unless "from __future__ import division" is included, in
1270 which case the / operator will provide true division. The operator
1271 module provides truediv() and floordiv() functions. Augmented
1272 assignment variants are included, as are the equivalent overloadable
1273 methods and C API methods. See the PEP for a full discussion:
1274 <http://python.sf.net/peps/pep-0238.html>
1275
Tim Peters6cd6a822001-08-17 22:11:27 +00001276- Future statements are now effective in simulated interactive shells
1277 (like IDLE). This should "just work" by magic, but read Michael
1278 Hudson's "Future statements in simulated shells" PEP 264 for full
1279 details: <http://python.sf.net/peps/pep-0264.html>.
1280
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001281- The type/class unification (PEP 252-253) was integrated into the
1282 trunk and is not so tentative any more (the exact specification of
1283 some features is still tentative). A lot of work has done on fixing
1284 bugs and adding robustness and features (performance still has to
1285 come a long way).
1286
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001287- Warnings about a mismatch in the Python API during extension import
1288 now use the Python warning framework (which makes it possible to
1289 write filters for these warnings).
1290
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001291- A function's __dict__ (aka func_dict) will now always be a
1292 dictionary. It used to be possible to delete it or set it to None,
1293 but now both actions raise TypeErrors. It is still legal to set it
1294 to a dictionary object. Getting func.__dict__ before any attributes
1295 have been assigned now returns an empty dictionary instead of None.
1296
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001297- A new command line option, -E, was added which disables the use of
1298 all environment variables, or at least those that are specifically
1299 significant to Python. Usually those have a name starting with
1300 "PYTHON". This was used to fix a problem where the tests fail if
1301 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1302 older distribution.
1303
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001304Library
1305
Tim Peters5e824c32001-08-12 22:25:01 +00001306- New class Differ and new functions ndiff() and restore() in difflib.py.
1307 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001308 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001309
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001310- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1311 value using the minimal quoting required for the value; more
1312 reliable than using xml.sax.saxutils.escape() for attribute values.
1313
1314- Readline completion support for cmd.Cmd was added.
1315
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001316- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1317
1318- Added function threading.BoundedSemaphore()
1319
1320- Added Ka-Ping Yee's cgitb.py module.
1321
1322- The `new' module now exposes the CO_xxx flags.
1323
Martin v. Löwis560da622001-11-24 09:24:51 +00001324- The gc module offers the get_referents function.
1325
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001326New platforms
1327
1328C API
1329
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001330- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1331 which provide a cross-platform implementations for the
1332 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1333 the standard sprintf() and vsprintf() C lib APIs, these versions
1334 apply bounds checking on the used buffer which enhances protection
1335 against buffer overruns.
1336
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001337- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001338 and extensions using different Unicode widths is rendered next to
1339 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001340 will result in an ImportError. Unicode extensions writers must make
1341 sure to check the Unicode width compatibility in their extensions by
1342 using at least one of the mangled Unicode APIs in the extension.
1343
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001344- Two new flags METH_NOARGS and METH_O are available in method definition
1345 tables to simplify implementation of methods with no arguments and a
1346 single untyped argument. Calling such methods is more efficient than
1347 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1348 deprecated.
1349
Tim Petersc1731372001-08-04 08:12:36 +00001350Windows
1351
1352- "import module" now compiles module.pyw if it exists and nothing else
1353 relevant is found.
1354
Tim Peters20f51a72001-07-21 02:31:40 +00001355
Guido van Rossum55a78992001-07-17 17:22:32 +00001356What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001357Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001358===========================
1359
1360Core
Tim Petersa814db52001-05-14 07:05:58 +00001361
Tim Peters6d6c1a32001-08-02 04:15:00 +00001362- TENTATIVELY, a large amount of code implementing much of what's
1363 described in PEP 252 (Making Types Look More Like Classes) and PEP
1364 253 (Subtyping Built-in Types) was added. This will be released
1365 with Python 2.2a1. Documentation will be provided separately
1366 through http://www.python.org/2.2/. The purpose of releasing this
1367 with Python 2.2a1 is to test backwards compatibility. It is
1368 possible, though not likely, that a decision is made not to release
1369 this code as part of 2.2 final, if any serious backwards
1370 incompapatibilities are found during alpha testing that cannot be
1371 repaired.
1372
Guido van Rossum55a78992001-07-17 17:22:32 +00001373- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001374 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001375 more 'yield' statements. See PEP 255. Since this adds a new
1376 keyword to the language, this feature must be enabled by including a
1377 future statement: "from __future__ import generators" (see PEP 236).
1378 Generators will become a standard feature in a future release
1379 (probably 2.3). Without this future statement, 'yield' remains an
1380 ordinary identifier, but a warning is issued each time it is used.
1381 (These warnings currently don't conform to the warnings framework of
1382 PEP 230; we intend to fix this in 2.2a2.)
1383
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001384- The UTF-16 codec was modified to be more RFC compliant. It will now
1385 only remove BOM characters at the start of the string and then
1386 only if running in native mode (UTF-16-LE and -BE won't remove a
1387 leading BMO character).
1388
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001389- Strings now have a new method .decode() to complement the already
1390 existing .encode() method. These two methods provide direct access
1391 to the corresponding decoders and encoders of the registered codecs.
1392
1393 To enhance the usability of the .encode() method, the special
1394 casing of Unicode object return values was dropped (Unicode objects
1395 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001396
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001397 Both methods will now return whatever the codec in charge of the
1398 requested encoding returns as object, e.g. Unicode codecs will
1399 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1400 will return u"äöü"). This enables codec writer to create codecs
1401 for various simple to use conversions.
1402
1403 New codecs were added to demonstrate these new features (the .encode()
1404 and .decode() columns indicate the type of the returned objects):
1405
1406 Name | .encode() | .decode() | Description
1407 ----------------------------------------------------------------------
1408 uu | string | string | UU codec (e.g. for email)
1409 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001410 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001411 zlib | string | string | zlib compression
1412 hex | string | string | 2-byte hex codec
1413 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1414
Mark Hammond2a0af792001-05-14 03:09:36 +00001415- Some operating systems now support the concept of a default Unicode
1416 encoding for file system operations. Notably, Windows supports 'mbcs'
1417 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001418 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001419 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001420
1421 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001422 functions that return filenames (such as os.listdir()) to return Python
1423 string objects pre-encoded using the default file system encoding for
1424 the platform. As this encoding is likely to be different from Python's
1425 default encoding, converting this name to a Unicode object before passing
1426 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001427 would attempt to use its default encoding (generally ASCII) rather than
1428 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001429
Tim Petersa814db52001-05-14 07:05:58 +00001430 In general, this change simply removes surprises when working with
1431 Unicode and the file system, making these operations work as you expect,
1432 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001433 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001434
Tim Peters61dff2b2001-05-08 15:43:37 +00001435- Float (and complex) literals in source code were evaluated to full
1436 precision only when running from a .py file; the same code loaded from a
1437 .pyc (or .pyo) file could suffer numeric differences starting at about the
1438 12th significant decimal digit. For example, on a machine with IEEE-754
1439 floating arithmetic,
1440
1441 x = 9007199254740992.0
1442 print long(x)
1443
1444 printed 9007199254740992 if run directly from .py, but 9007199254740000
1445 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1446 str(float) instead of repr(float) when building code objects. marshal
1447 now uses repr(float) instead, which should reproduce floats to full
1448 machine precision (assuming the platform C float<->string I/O conversion
1449 functions are of good quality).
1450
1451 This may cause floating-point results to change in some cases, and
1452 usually for the better, but may also cause numerically unstable
1453 algorithms to break.
1454
Tim Peters2f228e72001-05-13 00:19:31 +00001455- The implementation of dicts suffers fewer collisions, which has speed
1456 benefits. However, the order in which dict entries appear in dict.keys(),
1457 dict.values() and dict.items() may differ from previous releases for a
1458 given dict. Nothing is defined about this order, so no program should
1459 rely on it. Nevertheless, it's easy to write test cases that rely on the
1460 order by accident, typically because of printing the str() or repr() of a
1461 dict to an "expected results" file. See Lib/test/test_support.py's new
1462 sortdict(dict) function for a simple way to display a dict in sorted
1463 order.
1464
Tim Peters7a3bfc32001-06-12 01:22:22 +00001465- Many other small changes to dicts were made, resulting in faster
1466 operation along the most common code paths.
1467
Guido van Rossum10315822001-05-01 20:54:30 +00001468- Dictionary objects now support the "in" operator: "x in dict" means
1469 the same as dict.has_key(x).
1470
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001471- The update() method of dictionaries now accepts generic mapping
1472 objects. Specifically the argument object must support the .keys()
1473 and __getitem__() methods. This allows you to say, for example,
1474 {}.update(UserDict())
1475
Guido van Rossum10315822001-05-01 20:54:30 +00001476- Iterators were added; this is a generalized way of providing values
1477 to a for loop. See PEP 234. There's a new built-in function iter()
1478 to return an iterator. There's a new protocol to get the next value
1479 from an iterator using the next() method (in Python) or the
1480 tp_iternext slot (in C). There's a new protocol to get iterators
1481 using the __iter__() method (in Python) or the tp_iter slot (in C).
1482 Iterating (i.e. a for loop) over a dictionary generates its keys.
1483 Iterating over a file generates its lines.
1484
Tim Petersf553f892001-05-01 20:45:31 +00001485- The following functions were generalized to work nicely with iterator
1486 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001487 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001488 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1489 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001490 join() method of strings
1491 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001492 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1493 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001494 right-hand side of assignment statements with multiple targets, such as
1495 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001496
Tim Petersd85e1022001-05-11 21:51:48 +00001497- Accessing module attributes is significantly faster (for example,
1498 random.random or os.path or yourPythonModule.yourAttribute).
1499
Tim Peterse63415e2001-05-08 04:38:29 +00001500- Comparing dictionary objects via == and != is faster, and now works even
1501 if the keys and values don't support comparisons other than ==.
1502
Tim Peters95bf9392001-05-10 08:32:44 +00001503- Comparing dictionaries in ways other than == and != is slower: there were
1504 insecurities in the dict comparison implementation that could cause Python
1505 to crash if the element comparison routines for the dict keys and/or
1506 values mutated the dicts. Making the code bulletproof slowed it down.
1507
Tim Peterseb28ef22001-06-02 05:27:19 +00001508- Collisions in dicts are resolved via a new approach, which can help
1509 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001510 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001511 faster now. Thanks to Christian Tismer for pointing out the cause and
1512 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001513
Tim Peters52e155e2001-06-16 05:42:57 +00001514- repr() is much faster for large containers (dict, list, tuple).
1515
1516
Tim Petersa814db52001-05-14 07:05:58 +00001517Library
1518
Fred Drake960fdf92001-07-20 18:38:26 +00001519- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1520 were added to the string module. These a locale-indenpendent
1521 constants, unlike letters, lowercase, and uppercase. These are now
1522 use in appropriate locations in the standard library.
1523
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001524- The flags used in dlopen calls can now be configured using
1525 sys.setdlopenflags and queried using sys.getdlopenflags.
1526
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001527- Fredrik Lundh's xmlrpclib is now a standard library module. This
1528 provides full client-side XML-RPC support. In addition,
1529 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1530 one asyncore-based). Thanks to Eric Raymond for the documentation.
1531
Guido van Rossum643d3912001-07-05 14:46:25 +00001532- The xrange() object is simplified: it no longer supports slicing,
1533 repetition, comparisons, efficient 'in' checking, the tolist()
1534 method, or the start, stop and step attributes. See PEP 260.
1535
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001536- A new function fnmatch.filter to filter lists of file names was added.
1537
Barry Warsawffd674d2001-05-22 16:00:10 +00001538- calendar.py uses month and day names based on the current locale.
1539
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001540- strop is now *really* obsolete (this was announced before with 1.6),
1541 and issues DeprecationWarning when used (except for the four items
1542 that are still imported into string.py).
1543
Tim Petersa814db52001-05-14 07:05:58 +00001544- Cookie.py now sorts key+value pairs by key in output strings.
1545
1546- pprint.isrecursive(object) didn't correctly identify recursive objects.
1547 Now it does.
1548
Tim Peters95b3f782001-05-14 18:39:41 +00001549- pprint functions now much faster for large containers (tuple, list, dict).
1550
Tim Peters7b9542a2001-06-10 23:40:19 +00001551- New 'q' and 'Q' format codes in the struct module, corresponding to C
1552 types "long long" and "unsigned long long" (on Windows, __int64). In
1553 native mode, these can be used only when the platform C compiler supports
1554 these types (when HAVE_LONG_LONG is #define'd by the Python config
1555 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001556 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1557 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001558
Guido van Rossum83213cc2001-06-12 16:48:52 +00001559- The site module installs a new built-in function 'help' that invokes
1560 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1561 it displays a message reminding the user to use 'help()' or
1562 'help(object)'.
1563
Tim Petersa814db52001-05-14 07:05:58 +00001564Tests
1565
1566- New test_mutants.py runs dict comparisons where the key and value
1567 comparison operators mutute the dicts randomly during comparison. This
1568 rapidly causes Python to crash under earlier releases (not for the faint
1569 of heart: it can also cause Win9x to freeze or reboot!).
1570
1571- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001572 pprint.isreadable() return sensible results. Also verifies that simple
1573 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001574
Tim Peters4324aa32001-05-28 22:30:08 +00001575C API
1576
1577- Removed the unused last_is_sticky argument from the internal
1578 _PyTuple_Resize(). If this affects you, you were cheating.
1579
1580
Guido van Rossum55a78992001-07-17 17:22:32 +00001581======================================================================
1582
1583
Guido van Rossumffe13be2001-04-16 18:46:45 +00001584What's New in Python 2.1 (final)?
1585=================================
1586
1587We only changed a few things since the last release candidate, all in
1588Python library code:
1589
1590- A bug in the locale module was fixed that affected locales which
1591 define no grouping for numeric formatting.
1592
1593- A few bugs in the weakref module's implementations of weak
1594 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1595 and the test suite was updated to check for these bugs.
1596
1597- An old bug in the os.path.walk() function (introduced in Python
1598 2.0!) was fixed: a non-existent file would cause an exception
1599 instead of being ignored.
1600
1601- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1602 PyChecker.
1603
1604
Guido van Rossum5b08f132001-04-16 02:05:23 +00001605What's New in Python 2.1c2?
1606===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001607
Guido van Rossum5b08f132001-04-16 02:05:23 +00001608A flurry of small changes, and one showstopper fixed in the nick of
1609time made it necessary to release another release candidate. The list
1610here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001611
Guido van Rossum5b08f132001-04-16 02:05:23 +00001612Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001613
Guido van Rossum5b08f132001-04-16 02:05:23 +00001614- Tim discovered a nasty bug in the dictionary code, caused by
1615 PyDict_Next() calling dict_resize(), and the GC code's use of
1616 PyDict_Next() violating an assumption in dict_items(). This was
1617 fixed with considerable amounts of band-aid, but the net effect is a
1618 saner and more robust implementation.
1619
1620- Made a bunch of symbols static that were accidentally global.
1621
1622Build and Ports
1623
1624- The setup.py script didn't check for a new enough version of zlib
1625 (1.1.3 is needed). Now it does.
1626
1627- Changed "make clean" target to also remove shared libraries.
1628
1629- Added a more general warning about the SGI Irix optimizer to README.
1630
1631Library
1632
1633- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1634 omitted the slash between host and file.html.
1635
1636- The mailbox module's _Mailbox class contained a completely broken
1637 and undocumented seek() method. Ripped it out.
1638
1639- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1640 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1641
1642- Fixed a few last-minute bugs in unittest.
1643
1644Extensions
1645
1646- Reverted the patch to the OpenSSL code in socketmodule.c to support
1647 RAND_status() and the EGD, and the subsequent patch that tried to
1648 fix it for pre-0.9.5 versions; the problem with the patch is that on
1649 some systems it issues a warning whenever socket is imported, and
1650 that's unacceptable.
1651
1652Tests
1653
1654- Fixed the pickle tests to work with "import test.test_pickle".
1655
1656- Tweaked test_locale.py to actually run the test Windows.
1657
1658- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1659 not "wb" (which is not a valid mode at all).
1660
1661- Fix pstats browser crashes. Import readline if it exists to make
1662 the user interface nicer.
1663
1664- Add "import thread" to the top of test modules that import the
1665 threading module (test_asynchat and test_threadedtempfile). This
1666 prevents test failures caused by a broken threading module resulting
1667 from a previously caught failed import.
1668
1669- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1670 needed on some platforms (e.g. Solaris 8) when the tests are run
1671 twice in succession.
1672
1673- Skip rather than fail test_sunaudiodev if no audio device is found.
1674
1675
1676What's New in Python 2.1c1?
1677===========================
1678
1679This list was significantly updated when 2.1c2 was released; the 2.1c1
1680release didn't mention most changes that were actually part of 2.1c1:
1681
1682Legal
1683
1684- Copyright was assigned to the Python Software Foundation (PSF) and a
1685 PSF license (very similar to the CNRI license) was added.
1686
1687- The CNRI copyright notice was updated to include 2001.
1688
1689Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001690
Guido van Rossumc9932722001-04-12 02:31:27 +00001691- After a public outcry, assignment to __debug__ is no longer illegal;
1692 instead, a warning is issued. It will become illegal in 2.2.
1693
Guido van Rossum5b08f132001-04-16 02:05:23 +00001694- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1695 "%#x" now always prepends "0x", even if the value is zero.
1696
1697- Fixed some nits in the bytecode compiler.
1698
1699- Fixed core dumps when calling certain kinds of non-functions.
1700
1701- Fixed various core dumps caused by reference count bugs.
1702
1703Build and Ports
1704
1705- Use INSTALL_SCRIPT to install script files.
1706
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001707- New port: SCO Unixware 7, by Billy G. Allie.
1708
Guido van Rossum5b08f132001-04-16 02:05:23 +00001709- Updated RISCOS port.
1710
1711- Updated BeOS port and notes.
1712
1713- Various other porting problems resolved.
1714
1715Library
1716
1717- The TERMIOS and SOCKET modules are now truly obsolete and
1718 unnecessary. Their symbols are incorporated in the termios and
1719 socket modules.
1720
1721- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1722 better tests for pickling.
1723
1724- threading: make Condition.wait() robust against KeyboardInterrupt.
1725
1726- zipfile: add support to zipfile to support opening an archive
1727 represented by an open file rather than a file name. Fix bug where
1728 the archive was not properly closed. Fixed a bug in this bugfix
1729 where flush() was called for a read-only file.
1730
1731- imputil: added an uninstall() method to the ImportManager.
1732
1733- Canvas: fixed bugs in lower() and tkraise() methods.
1734
1735- SocketServer: API change (added overridable close_request() method)
1736 so that the TCP server can explicitly close the request.
1737
1738- pstats: Eric Raymond added a simple interactive statistics browser,
1739 invoked when the module is run as a script.
1740
1741- locale: fixed a problem in format().
1742
1743- webbrowser: made it work when the BROWSER environment variable has a
1744 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1745 KDE 2. Fixed some other nits.
1746
1747- unittest: changes to allow using a different exception than
1748 AssertionError, and added a few more function aliases. Some other
1749 small changes.
1750
1751- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1752
1753- asynchat: fixed a critical bug in asynchat that slipped through the
1754 2.1b2 release. Fixed another rare bug.
1755
1756- Fix some unqualified except: clauses (always a bad code example).
1757
1758XML
1759
1760- pyexpat: new API get_version_string().
1761
1762- Fixed some minidom bugs.
1763
1764Extensions
1765
1766- Fixed a core dump in _weakref. Removed the weakref.mapping()
1767 function (it adds nothing to the API).
1768
1769- Rationalized the use of header files in the readline module, to make
1770 it compile (albeit with some warnings) with the very recent readline
1771 4.2, without breaking for earlier versions.
1772
1773- Hopefully fixed a buffering problem in linuxaudiodev.
1774
1775- Attempted a fix to make the OpenSSL support in the socket module
1776 work again with pre-0.9.5 versions of OpenSSL.
1777
1778Tests
1779
1780- Added a test case for asynchat and asyncore.
1781
1782- Removed coupling between tests where one test failing could break
1783 another.
1784
1785Tools
1786
1787- Ping added an interactive help browser to pydoc, fixed some nits
1788 in the rest of the pydoc code, and added some features to his
1789 inspect module.
1790
1791- An updated python-mode.el version 4.1 which integrates Ken
1792 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1793 much nicer in XEmacs and Emacs. When stepping through your program
1794 with pdb, in either the shell window or the *Python* window, the
1795 source file and line will be tracked by an arrow. Very cool!
1796
1797- IDLE: syntax warnings in interactive mode are changed into errors.
1798
1799- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001800 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001801
1802- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001803
Barry Warsaw11e89c72001-04-11 20:37:57 +00001804
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001805What's New in Python 2.1 beta 2?
1806================================
1807
Guido van Rossum053ae352001-03-22 14:17:21 +00001808(Unlisted are many fixed bugs, more documentation, etc.)
1809
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001810Core language, builtins, and interpreter
1811
Guido van Rossum053ae352001-03-22 14:17:21 +00001812- The nested scopes work (enabled by "from __future__ import
1813 nested_scopes") is completed; in particular, the future now extends
1814 into code executed through exec, eval() and execfile(), and into the
1815 interactive interpreter.
1816
1817- When calling a base class method (e.g. BaseClass.__init__(self)),
1818 this is now allowed even if self is not strictly spoken a class
1819 instance (e.g. when using metaclasses or the Don Beaudry hook).
1820
1821- Slice objects are now comparable but not hashable; this prevents
1822 dict[:] from being accepted but meaningless.
1823
1824- Complex division is now calculated using less braindead algorithms.
1825 This doesn't change semantics except it's more likely to give useful
1826 results in extreme cases. Complex repr() now uses full precision
1827 like float repr().
1828
1829- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1830
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001831- It is illegal to assign to the name __debug__, which is set when the
1832 interpreter starts. It is effectively a compile-time constant.
1833
1834- A warning will be issued if a global statement for a variable
1835 follows a use or assignment of that variable.
1836
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001837Standard library
1838
Guido van Rossum053ae352001-03-22 14:17:21 +00001839- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1840 inspired by JUnit), is now part of the standard library. You now
1841 have a choice of two testing frameworks: unittest requires you to
1842 write testcases as separate code, doctest gathers them from
1843 docstrings. Both approaches have their advantages and
1844 disadvantages.
1845
1846- A new module Tix was added, which wraps the Tix extension library
1847 for Tk. With that module, it is not necessary to statically link
1848 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1849 require" command. See Demo/tix/.
1850
1851- tzparse.py is now obsolete.
1852
1853- In gzip.py, the seek() and tell() methods are removed -- they were
1854 non-functional anyway, and it's better if callers can test for their
1855 existence with hasattr().
1856
1857Python/C API
1858
1859- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1860 that's already in the dictionary during a PyDict_Next() iteration.
1861 This used to fail occasionally when a dictionary resize operation
1862 could be triggered that would rehash all the keys. All other
1863 modifications to the dictionary are still off-limits during a
1864 PyDict_Next() iteration!
1865
1866- New extended APIs related to passing compiler variables around.
1867
1868- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1869 implement isinstance() and issubclass().
1870
1871- Py_BuildValue() now has a "D" conversion to create a Python complex
1872 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001873
Fred Drake4e262a92001-03-22 18:26:47 +00001874- Extensions types which support weak references must now set the
1875 field allocated for the weak reference machinery to NULL themselves;
1876 this is done to avoid the cost of checking each object for having a
1877 weakly referencable type in PyObject_INIT(), since most types are
1878 not weakly referencable.
1879
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001880- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1881 free variables and cell variables to and from the frame's f_locals.
1882
1883- Variants of several functions defined in pythonrun.h have been added
1884 to support the nested_scopes future statement. The variants all end
1885 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1886 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1887 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001888 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001889
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001890Distutils
1891
1892- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1893 into the release tree.
1894
Tim Peters0e57abf2001-05-02 07:39:38 +00001895- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001896 (an uninstaller, more customization of the installer's display)
1897
1898- from Jack Jansen: added Mac-specific code to generate a dialog for
1899 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001900 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001901 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001902
1903- added 'platforms' and 'keywords' to the set of metadata that can be
1904 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001905
1906- applied patches from Jason Tishler to make the compiler class work with
1907 Cygwin.
1908
1909
Tim Peters2fe289a2001-03-01 22:19:38 +00001910What's New in Python 2.1 beta 1?
1911================================
Tim Petersd66595f2001-02-04 03:09:53 +00001912
1913Core language, builtins, and interpreter
1914
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001915- Following an outcry from the community about the amount of code
1916 broken by the nested scopes feature introduced in 2.1a2, we decided
1917 to make this feature optional, and to wait until Python 2.2 (or at
1918 least 6 months) to make it standard. The option can be enabled on a
1919 per-module basis by adding "from __future__ import nested_scopes" at
1920 the beginning of a module (before any other statements, but after
1921 comments and an optional docstring). See PEP 236 (Back to the
1922 __future__) for a description of the __future__ statement. PEP 227
1923 (Statically Nested Scopes) has been updated to reflect this change,
1924 and to clarify the semantics in a number of endcases.
1925
1926- The nested scopes code, when enabled, has been hardened, and most
1927 bugs and memory leaks in it have been fixed.
1928
1929- Compile-time warnings are now generated for a number of conditions
1930 that will break or change in meaning when nested scopes are enabled:
1931
1932 - Using "from...import *" or "exec" without in-clause in a function
1933 scope that also defines a lambda or nested function with one or
1934 more free (non-local) variables. The presence of the import* or
1935 bare exec makes it impossible for the compiler to determine the
1936 exact set of local variables in the outer scope, which makes it
1937 impossible to determine the bindings for free variables in the
1938 inner scope. To avoid the warning about import *, change it into
1939 an import of explicitly name object, or move the import* statement
1940 to the global scope; to avoid the warning about bare exec, use
1941 exec...in... (a good idea anyway -- there's a possibility that
1942 bare exec will be deprecated in the future).
1943
1944 - Use of a global variable in a nested scope with the same name as a
1945 local variable in a surrounding scope. This will change in
1946 meaning with nested scopes: the name in the inner scope will
1947 reference the variable in the outer scope rather than the global
1948 of the same name. To avoid the warning, either rename the outer
1949 variable, or use a global statement in the inner function.
1950
Neil Schemenauera35c6882001-02-27 04:45:05 +00001951- An optional object allocator has been included. This allocator is
1952 optimized for Python objects and should be faster and use less memory
1953 than the standard system allocator. It is not enabled by default
1954 because of possible thread safety problems. The allocator is only
1955 protected by the Python interpreter lock and it is possible that some
1956 extension modules require a thread safe allocator. The object
1957 allocator can be enabled by providing the "--with-pymalloc" option to
1958 configure.
1959
Tim Petersd66595f2001-02-04 03:09:53 +00001960Standard library
1961
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001962- pyexpat now detects the expat version if expat.h defines it. A
1963 number of additional handlers are provided, which are only available
1964 since expat 1.95. In addition, the methods SetParamEntityParsing and
1965 GetInputContext of Parser objects are available with 1.95.x
1966 only. Parser objects now provide the ordered_attributes and
1967 specified_attributes attributes. A new module expat.model was added,
1968 which offers a number of additional constants if 1.95.x is used.
1969
1970- xml.dom offers the new functions registerDOMImplementation and
1971 getDOMImplementation.
1972
1973- xml.dom.minidom offers a toprettyxml method. A number of DOM
1974 conformance issues have been resolved. In particular, Element now
1975 has an hasAttributes method, and the handling of namespaces was
1976 improved.
1977
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001978- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1979 getting information about live Python code, and pydoc.py, a module
1980 for interactively converting docstrings to HTML or text.
1981 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001982 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001983 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1984 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001985
Tim Peters1eff7962001-03-01 02:31:33 +00001986- New library module difflib.py, primarily packaging the SequenceMatcher
1987 class at the heart of the popular ndiff.py file-comparison tool.
1988
1989- doctest.py (a framework for verifying Python code examples in docstrings)
1990 is now part of the std library.
1991
Tim Petersd66595f2001-02-04 03:09:53 +00001992Windows changes
1993
Guido van Rossume3955a82001-03-02 14:05:59 +00001994- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1995 small GUI that lets you browse the module docstrings using your
1996 default web browser.
1997
Tim Peters1eff7962001-03-01 02:31:33 +00001998- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1999 Platforms) is implemented. See
2000
2001 http://python.sourceforge.net/peps/pep-0235.html
2002
2003 for full details, especially the "Current Lower-Left Semantics" section.
2004 The new Windows import rules are simpler than before:
2005
2006 A. If the PYTHONCASEOK environment variable exists, same as
2007 before: silently accept the first case-insensitive match of any
2008 kind; raise ImportError if none found.
2009
2010 B. Else search sys.path for the first case-sensitive match; raise
2011 ImportError if none found.
2012
2013 The same rules have been implented on other platforms with case-
2014 insensitive but case-preserving filesystems too (including Cygwin, and
2015 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002016
Tim Peters25a9ce32001-02-19 07:06:36 +00002017- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2018 what it's supposed to do (and does do under NT and 2000) via direct
2019 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002020 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002021 all Win9x systems before.
2022
Tim Peters1eff7962001-03-01 02:31:33 +00002023- Build: Subproject _test (effectively) renamed to _testcapi.
2024
Tim Peters2fe289a2001-03-01 22:19:38 +00002025New platforms
2026
2027- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2028 Thanks to Steven Majewski!
2029
2030- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2031 Tishler!
2032
Guido van Rossum9089b272001-03-02 06:49:50 +00002033- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2034 Schwertberger! See RISCOS/README for more information -- it seems
2035 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002036 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002037
Tim Peters25a9ce32001-02-19 07:06:36 +00002038
Tim Petersd7b5e882001-01-25 03:36:26 +00002039What's New in Python 2.1 alpha 2?
2040=================================
Tim Peters40ead762001-01-27 05:35:26 +00002041
Tim Petersd7b5e882001-01-25 03:36:26 +00002042Core language, builtins, and interpreter
2043
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002044- Scopes nest. If a name is used in a function or class, but is not
2045 local, the definition in the nearest enclosing function scope will
2046 be used. One consequence of this change is that lambda statements
2047 could reference variables in the namespaces where the lambda is
2048 defined. In some unusual cases, this change will break code.
2049
2050 In all previous version of Python, names were resolved in exactly
2051 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002052 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002053 function A is defined within a function B, the names bound in B are
2054 not visible in A. The new rules make names bound in B visible in A,
2055 unless A contains a name binding that hides the binding in B.
2056
2057 Section 4.1 of the reference manual describes the new scoping rules
2058 in detail. The test script in Lib/test/test_scope.py demonstrates
2059 some of the effects of the change.
2060
2061 The new rules will cause existing code to break if it defines nested
2062 functions where an outer function has local variables with the same
2063 name as globals or builtins used by the inner function. Example:
2064
2065 def munge(str):
2066 def helper(x):
2067 return str(x)
2068 if type(str) != type(''):
2069 str = helper(str)
2070 return str.strip()
2071
2072 Under the old rules, the name str in helper() is bound to the
2073 builtin function str(). Under the new rules, it will be bound to
2074 the argument named str and an error will occur when helper() is
2075 called.
2076
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002077- The compiler will report a SyntaxError if "from ... import *" occurs
2078 in a function or class scope. The language reference has documented
2079 that this case is illegal, but the compiler never checked for it.
2080 The recent introduction of nested scope makes the meaning of this
2081 form of name binding ambiguous. In a future release, the compiler
2082 may allow this form when there is no possibility of ambiguity.
2083
Tim Peters40ead762001-01-27 05:35:26 +00002084- repr(string) is easier to read, now using hex escapes instead of octal,
2085 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2086
2087 >>> "\texample \r\n" + chr(0) + chr(255)
2088 '\texample \r\n\x00\xff' # in 2.1
2089 '\011example \015\012\000\377' # in 2.0
2090
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002091- Functions are now compared and hashed by identity, not by value, since
2092 the func_code attribute is writable.
2093
Fred Drakefb9d7122001-02-01 20:00:40 +00002094- Weak references (PEP 205) have been added. This involves a few
2095 changes in the core, an extension module (_weakref), and a Python
2096 module (weakref). The weakref module is the public interface. It
2097 includes support for "explicit" weak references, proxy objects, and
2098 mappings with weakly held values.
2099
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002100- A 'continue' statement can now appear in a try block within the body
2101 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002102 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002103
Tim Petersd7b5e882001-01-25 03:36:26 +00002104Standard library
2105
Barry Warsaw30dbd142001-01-31 22:14:01 +00002106- mailbox.py now has a new class, PortableUnixMailbox which is
2107 identical to UnixMailbox but uses a more portable scheme for
2108 determining From_ separators. Also, the constructors for all the
2109 classes in this module have a new optional `factory' argument, which
2110 is a callable used when new message classes must be instantiated by
2111 the next() method.
2112
Tim Petersd7b5e882001-01-25 03:36:26 +00002113- random.py is now self-contained, and offers all the functionality of
2114 the now-deprecated whrandom.py. See the docs for details. random.py
2115 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002116 and restoring the internal state of the generator; and jumpahead(n),
2117 for quickly forcing the internal state to be the same as if n calls to
2118 random() had been made. The latter is particularly useful for multi-
2119 threaded programs, creating one instance of the random.Random() class for
2120 each thread, then using .jumpahead() to force each instance to use a
2121 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002122
Tim Peters0de88fc2001-02-01 04:59:18 +00002123- random.py's seed() function is new. For bit-for-bit compatibility with
2124 prior releases, use the whseed function instead. The new seed function
2125 addresses two problems: (1) The old function couldn't produce more than
2126 about 2**24 distinct internal states; the new one about 2**45 (the best
2127 that can be done in the Wichmann-Hill generator). (2) The old function
2128 sometimes produced identical internal states when passed distinct
2129 integers, and there was no simple way to predict when that would happen;
2130 the new one guarantees to produce distinct internal states for all
2131 arguments in [0, 27814431486576L).
2132
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002133- The socket module now supports raw packets on Linux. The socket
2134 family is AF_PACKET.
2135
Tim Peters9ea17ac2001-02-02 05:57:15 +00002136- test_capi.py is a start at running tests of the Python C API. The tests
2137 are implemented by the new Modules/_testmodule.c.
2138
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002139- A new extension module, _symtable, provides provisional access to the
2140 internal symbol table used by the Python compiler. A higher-level
2141 interface will be added on top of _symtable in a future release.
2142
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002143- Removed the obsolete soundex module.
2144
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002145- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2146 the isSameNode method; NamedNodeMap the get method.
2147
2148- xml.sax.expatreader supports the lexical handler property; it
2149 generates comment, startCDATA, and endCDATA events.
2150
Tim Petersee826f82001-01-31 19:39:44 +00002151Windows changes
2152
2153- Build procedure: the zlib project is built in a different way that
2154 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002155 the zlib binary used. See PCbuild\readme.txt for details. Your old
2156 zlib-related directories can be deleted; you'll need to download fresh
2157 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002158
Tim Peters9ea17ac2001-02-02 05:57:15 +00002159- Build: New subproject _test for the benefit of test_capi.py (see above).
2160
Tim Petersb16c56f2001-02-02 21:24:51 +00002161- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2162 interface to some Python compiler internals).
2163
2164- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002165 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002166
Tim Petersa3a3a032000-11-30 05:22:44 +00002167What's New in Python 2.1 alpha 1?
2168=================================
2169
2170Core language, builtins, and interpreter
2171
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002172- There is a new Unicode companion to the PyObject_Str() API
2173 called PyObject_Unicode(). It behaves in the same way as the
2174 former, but assures that the returned value is an Unicode object
2175 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002176
Guido van Rossumf98eda02001-01-17 15:54:45 +00002177- The comparison operators support "rich comparison overloading" (PEP
2178 207). C extension types can provide a rich comparison function in
2179 the new tp_richcompare slot in the type object. The cmp() function
2180 and the C function PyObject_Compare() first try the new rich
2181 comparison operators before trying the old 3-way comparison. There
2182 is also a new C API PyObject_RichCompare() (which also falls back on
2183 the old 3-way comparison, but does not constrain the outcome of the
2184 rich comparison to a Boolean result).
2185
2186 The rich comparison function takes two objects (at least one of
2187 which is guaranteed to have the type that provided the function) and
2188 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2189 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2190 object, which may be NotImplemented (in which case the tp_compare
2191 slot function is used as a fallback, if defined).
2192
2193 Classes can overload individual comparison operators by defining one
2194 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002195 __ge__. There are no explicit "reflected argument" versions of
2196 these; instead, __lt__ and __gt__ are each other's reflection,
2197 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2198 reflection (similar at the C level). No other implications are
2199 made; in particular, Python does not assume that == is the Boolean
2200 inverse of !=, or that < is the Boolean inverse of >=. This makes
2201 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002202
2203 Classes or types that want to implement (in)equality tests but not
2204 the ordering operators (i.e. unordered types) should implement ==
2205 and !=, and raise an error for the ordering operators.
2206
Guido van Rossuma88479f2001-01-18 14:28:08 +00002207 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002208 Boolean; e.g. a matrix type might want to return a matrix of bits
2209 for A < B, giving elementwise comparisons. Such types should ensure
2210 that any interpretation of their value in a Boolean context raises
2211 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2212 at the C level) to always raise an exception.
2213
Guido van Rossuma88479f2001-01-18 14:28:08 +00002214- Complex numbers use rich comparisons to define == and != but raise
2215 an exception for <, <=, > and >=. Unfortunately, this also means
2216 that cmp() of two complex numbers raises an exception when the two
2217 numbers differ. Since it is not mathematically meaningful to compare
2218 complex numbers except for equality, I hope that this doesn't break
2219 too much code.
2220
Tim Peters3389f192001-02-18 08:48:49 +00002221- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002222 not defined by the language, other than that it's arbitrary but
2223 consistent (see the Reference Manual). An implementation detail changed
2224 in 2.1a1 such that None now compares less than any other object. Code
2225 relying on this new behavior (like code that relied on the previous
2226 behavior) does so at its own risk.
2227
Barry Warsaw573b5412001-01-15 20:43:18 +00002228- Functions and methods now support getting and setting arbitrarily
2229 named attributes (PEP 232). Functions have a new __dict__
2230 (a.k.a. func_dict) which hold the function attributes. Methods get
2231 and set attributes on their underlying im_func. It is a TypeError
2232 to set an attribute on a bound method.
2233
Guido van Rossum051e3352001-01-15 19:11:10 +00002234- The xrange() object implementation has been improved so that
2235 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2236 limitation that in this case len(xrange(sys.maxint)) can't be
2237 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2238 work fine as long as the index i doesn't actually reach 2**31.
2239 (Python uses regular ints for sequence and string indices; fixing
2240 that is much more work.)
2241
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002242- Two changes to from...import:
2243
Guido van Rossumba381232001-02-03 15:06:40 +00002244 1) "from M import X" now works even if (after loading module M)
2245 sys.modules['M'] is not a real module; it's basically a getattr()
2246 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002247
2248 2) "from M import *" now looks for M.__all__ to decide which names to
2249 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2250 filters out names starting with '_' as before. Whether or not
2251 __all__ exists, there's no restriction on the type of M.
2252
Guido van Rossumf61f1662001-01-10 20:13:55 +00002253- File objects have a new method, xreadlines(). This is the fastest
2254 way to iterate over all lines in a file:
2255
2256 for line in file.xreadlines():
2257 ...do something to line...
2258
2259 See the xreadlines module (mentioned below) for how to do this for
2260 other file-like objects.
2261
2262- Even if you don't use file.xreadlines(), you may expect a speedup on
2263 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002264 quite a bit in platform-specific ways: on systems (like Linux) that
2265 support flockfile(), getc_unlocked(), and funlockfile(), those are
2266 used by default. On systems (like Windows) without getc_unlocked(),
2267 a complicated (but still thread-safe) method using fgets() is used by
2268 default.
2269
Tim Petersd52269b2001-01-25 06:23:18 +00002270 You can force use of the fgets() method by #define'ing
2271 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002272 getc_unlocked()).
2273
Tim Petersd52269b2001-01-25 06:23:18 +00002274 You can force fgets() not to be used by #define'ing
2275 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002276 test_bufio.py fails -- and let us know if it does!).
2277
2278- In addition, the fileinput module, while still slower than the other
2279 methods on most platforms, has been sped up too, by using
2280 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002281
2282- Support for run-time warnings has been added, including a new
2283 command line option (-W) to specify the disposition of warnings.
2284 See the description of the warnings module below.
2285
2286- Extensive changes have been made to the coercion code. This mostly
2287 affects extension modules (which can now implement mixed-type
2288 numerical operators without having to use coercion), but
2289 occasionally, in boundary cases the coercion semantics have changed
2290 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002291 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002292 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002293 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002294
Guido van Rossumf98eda02001-01-17 15:54:45 +00002295- In connection with the coercion changes, a new built-in singleton
2296 object, NotImplemented is defined. This can be returned for
2297 operations that wish to indicate they are not implemented for a
2298 particular combination of arguments. From C, this is
2299 Py_NotImplemented.
2300
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002301- The interpreter accepts now bytecode files on the command line even
2302 if they do not have a .pyc or .pyo extension. On Linux, after executing
2303
Martin v. Löwise214baa2001-02-04 22:37:56 +00002304import imp,sys,string
2305magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2306reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2307open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002308
2309 any byte code file can be used as an executable (i.e. as an argument
2310 to execve(2)).
2311
Tim Peters9940b802000-12-01 07:59:35 +00002312- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002313 character. In 1.6 and earlier, they never produced a sign,
2314 and raised an error if the value of the long was too large
2315 to fit in a Python int. In 2.0, they produced a sign if and
2316 only if too large to fit in an int. This was inconsistent
2317 across platforms (because the size of an int varies across
2318 platforms), and inconsistent with hex() and oct(). Example:
2319
2320 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002321 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002322 'ffffffbe' # in 2.0 and before, on 32-bit machines
2323 >>> hex(-0x42L)
2324 '-0x42L' # in all versions of Python
2325
Tim Peters9940b802000-12-01 07:59:35 +00002326 The behavior of %d formats for negative Python longs remains
2327 the same as in 2.0 (although in 1.6 and before, they raised
2328 an error if the long didn't fit in a Python int).
2329
2330 %u formats don't make sense for Python longs, but are allowed
2331 and treated the same as %d in 2.1. In 2.0, a negative long
2332 formatted via %u produced a sign if and only if too large to
2333 fit in an int. In 1.6 and earlier, a negative long formatted
2334 via %u raised an error if it was too big to fit in an int.
2335
Guido van Rossum3661d392000-12-12 22:10:31 +00002336- Dictionary objects have an odd new method, popitem(). This removes
2337 an arbitrary item from the dictionary and returns it (in the form of
2338 a (key, value) pair). This can be useful for algorithms that use a
2339 dictionary as a bag of "to do" items and repeatedly need to pick one
2340 item. Such algorithms normally end up running in quadratic time;
2341 using popitem() they can usually be made to run in linear time.
2342
Tim Peters36cdad12000-12-29 02:06:45 +00002343Standard library
2344
Thomas Woutersfe385252001-01-19 23:16:56 +00002345- In the time module, the time argument to the functions strftime,
2346 localtime, gmtime, asctime and ctime is now optional, defaulting to
2347 the current time (in the local timezone).
2348
Guido van Rossumda91f222001-01-15 16:36:08 +00002349- The ftplib module now defaults to passive mode, which is deemed a
2350 more useful default given that clients are often inside firewalls
2351 these days. Note that this could break if ftplib is used to connect
2352 to a *server* that is inside a firewall, from outside; this is
2353 expected to be a very rare situation. To fix that, you can call
2354 ftp.set_pasv(0).
2355
Martin v. Löwis10a27872001-01-13 09:54:41 +00002356- The module site now treats .pth files not only for path configuration,
2357 but also supports extensions to the initialization code: Lines starting
2358 with import are executed.
2359
Guido van Rossumf61f1662001-01-10 20:13:55 +00002360- There's a new module, warnings, which implements a mechanism for
2361 issuing and filtering warnings. There are some new built-in
2362 exceptions that serve as warning categories, and a new command line
2363 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2364 turns warnings into errors). warnings.warn(message[, category])
2365 issues a warning message; this can also be called from C as
2366 PyErr_Warn(category, message).
2367
2368- A new module xreadlines was added. This exports a single factory
2369 function, xreadlines(). The intention is that this code is the
2370 absolutely fastest way to iterate over all lines in an open
2371 file(-like) object:
2372
2373 import xreadlines
2374 for line in xreadlines.xreadlines(file):
2375 ...do something to line...
2376
2377 This is equivalent to the previous the speed record holder using
2378 file.readlines(sizehint). Note that if file is a real file object
2379 (as opposed to a file-like object), this is equivalent:
2380
2381 for line in file.xreadlines():
2382 ...do something to line...
2383
Tim Peters36cdad12000-12-29 02:06:45 +00002384- The bisect module has new functions bisect_left, insort_left,
2385 bisect_right and insort_right. The old names bisect and insort
2386 are now aliases for bisect_right and insort_right. XXX_right
2387 and XXX_left methods differ in what happens when the new element
2388 compares equal to one or more elements already in the list: the
2389 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002390 right. Code that doesn't care where equal elements end up should
2391 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002392
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002393- The new curses.panel module wraps the panel library that forms part
2394 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2395
Guido van Rossumf61f1662001-01-10 20:13:55 +00002396- The SocketServer module now sets the allow_reuse_address flag by
2397 default in the TCPServer class.
2398
2399- A new function, sys._getframe(), returns the stack frame pointer of
2400 the caller. This is intended only as a building block for
2401 higher-level mechanisms such as string interpolation.
2402
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002403- The pyexpat module supports a number of new handlers, which are
2404 available only in expat 1.2. If invocation of a callback fails, it
2405 will report an additional frame in the traceback. Parser objects
2406 participate now in garbage collection. If expat reports an unknown
2407 encoding, pyexpat will try to use a Python codec; that works only
2408 for single-byte charsets. The parser type objects is exposed as
2409 XMLParserObject.
2410
2411- xml.dom now offers standard definitions for symbolic node type and
2412 exception code constants, and a hierarchy of DOM exceptions. minidom
2413 was adjusted to use them.
2414
2415- The conformance of xml.dom.minidom to the DOM specification was
2416 improved. It detects a number of additional error cases; the
2417 previous/next relationship works even when the tree is modified;
2418 Node supports the normalize() method; NamedNodeMap, DocumentType and
2419 DOMImplementation classes were added; Element supports the
2420 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2421 method.
2422
Guido van Rossumf61f1662001-01-10 20:13:55 +00002423Build issues
2424
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002425- For Unix (and Unix-compatible) builds, configuration and building of
2426 extension modules is now greatly automated. Rather than having to
2427 edit the Modules/Setup file to indicate which modules should be
2428 built and where their include files and libraries are, a
2429 distutils-based setup.py script now takes care of building most
2430 extension modules. All extension modules built this way are built
2431 as shared libraries. Only a few modules that must be linked
2432 statically are still listed in the Setup file; you won't need to
2433 edit their configuration.
2434
2435- Python should now build out of the box on Cygwin. If it doesn't,
2436 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002437
2438- Python now always uses its own (renamed) implementation of getopt()
2439 -- there's too much variation among C library getopt()
2440 implementations.
2441
2442- C++ compilers are better supported; the CXX macro is always set to a
2443 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002444
Tim Petersd92dfe02000-12-12 01:18:41 +00002445Windows changes
2446
2447- select module: By default under Windows, a select() call
2448 can specify no more than 64 sockets. Python now boosts
2449 this Microsoft default to 512. If you need even more than
2450 that, see the MS docs (you'll need to #define FD_SETSIZE
2451 and recompile Python from source).
2452
Guido van Rossumf61f1662001-01-10 20:13:55 +00002453- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2454 subdirectory is no more!
2455
Tim Petersa3a3a032000-11-30 05:22:44 +00002456
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002457What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002458=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002459
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002460Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002461changes are in the file HISTORY. If you are making the jump directly
2462from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2463HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002464
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002465Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2466the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2467http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002468
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002469--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002470
2471======================================================================
2472
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002473What's new in 2.0 (since release candidate 1)?
2474==============================================
2475
2476Standard library
2477
2478- The copy_reg module was modified to clarify its intended use: to
2479 register pickle support for extension types, not for classes.
2480 pickle() will raise a TypeError if it is passed a class.
2481
2482- Fixed a bug in gettext's "normalize and expand" code that prevented
2483 it from finding an existing .mo file.
2484
2485- Restored support for HTTP/0.9 servers in httplib.
2486
Tim Peters989b7b92000-10-16 20:24:53 +00002487- The math module was changed to stop raising OverflowError in case of
2488 underflow, and return 0 instead in underflow cases. Whether Python
2489 used to raise OverflowError in case of underflow was platform-
2490 dependent (it did when the platform math library set errno to ERANGE
2491 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002492
2493- Fixed a bug in StringIO that occurred when the file position was not
2494 at the end of the file and write() was called with enough data to
2495 extend past the end of the file.
2496
2497- Fixed a bug that caused Tkinter error messages to get lost on
2498 Windows. The bug was fixed by replacing direct use of
2499 interp->result with Tcl_GetStringResult(interp).
2500
2501- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2502 redirect response.
2503
2504- Several changes were made to distutils: Some debugging code was
2505 removed from util. Fixed the installer used when an external zip
2506 program (like WinZip) is not found; the source code for this
2507 installer is in Misc/distutils. check_lib() was modified to behave
2508 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2509 test for whether installed modules are on sys.path was changed to
2510 use both normcase() and normpath().
2511
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002512- Several minor bugs were fixed in the xml package (the minidom,
2513 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002514
2515- The regression test driver (regrtest.py) behavior when invoked with
2516 -l changed: It now reports a count of objects that are recognized as
2517 garbage but not freed by the garbage collector.
2518
Tim Peters989b7b92000-10-16 20:24:53 +00002519- The regression test for the math module was changed to test
2520 exceptional behavior when the test is run in verbose mode. Python
2521 cannot yet guarantee consistent exception behavior across platforms,
2522 so the exception part of test_math is run only in verbose mode, and
2523 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002524
2525Internals
2526
2527- PyOS_CheckStack() has been disabled on Win64, where it caused
2528 test_sre to fail.
2529
2530Build issues
2531
2532- Changed compiler flags, so that gcc is always invoked with -Wall and
2533 -Wstrict-prototypes. Users compiling Python with GCC should see
2534 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002535 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002536 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002537
Tim Petersa3a3a032000-11-30 05:22:44 +00002538- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002539
2540Tools and other miscellany
2541
2542- The compiler in Tools/compiler was updated to support the new
2543 language features introduced in 2.0: extended print statement, list
2544 comprehensions, and augmented assignments. The new compiler should
2545 also be backwards compatible with Python 1.5.2; the compiler will
2546 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002547 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002548
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002549What's new in 2.0 release candidate 1 (since beta 2)?
2550=====================================================
2551
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002552What is release candidate 1?
2553
2554We believe that release candidate 1 will fix all known bugs that we
2555intend to fix for the 2.0 final release. This release should be a bit
2556more stable than the previous betas. We would like to see even more
2557widespread testing before the final release, so we are producing this
2558release candidate. The final release will be exactly the same unless
2559any show-stopping (or brown bag) bugs are found by testers of the
2560release candidate.
2561
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002562All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002563to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002564
2565Core language, builtins, and interpreter
2566
2567- A bug that caused crashes when __coerce__ was used with augmented
2568 assignment, e.g. +=, was fixed.
2569
2570- Raise ZeroDivisionError when raising zero to a negative number,
2571 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2572 power operator and the result of math.pow(0.0, -2.0) will vary by
2573 platform. On Linux, it raises a ValueError.
2574
2575- A bug in Unicode string interpolation was fixed that occasionally
2576 caused errors with formats including "%%". For example, the
2577 following expression "%% %s" % u"abc" no longer raises a TypeError.
2578
2579- Compilation of deeply nested expressions raises MemoryError instead
2580 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2581
2582- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2583 rendering them useless. They are now written in binary mode again.
2584
2585Standard library
2586
2587- Keyword arguments are now accepted for most pattern and match object
2588 methods in SRE, the standard regular expression engine.
2589
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002590- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002591 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002592
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002593- Several bugs in the Unicode handling and error handling in _tkinter
2594 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002595
2596- Fix memory management errors in Merge() and Tkapp_Call() routines.
2597
2598- Several changes were made to cStringIO to make it compatible with
2599 the file-like object interface and with StringIO. If operations are
2600 performed on a closed object, an exception is raised. The truncate
2601 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002602 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002603
2604- There were many changes made to the linuxaudiodev module and its
2605 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002606 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002607
2608 Note that this module is named poorly, because it should work
2609 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002610 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002611
2612 The module now raises exceptions when errors occur instead of
2613 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2614 audio) and defines a getptr() method that calls the
2615 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2616
2617- The library_version attribute, introduced in an earlier beta, was
2618 removed because it can not be supported with early versions of the C
2619 readline library, which provides no way to determine the version at
2620 compile-time.
2621
2622- The binascii module is now enabled on Win64.
2623
Tim Peters46446d62000-10-09 21:19:31 +00002624- tokenize.py no longer suffers "recursion depth" errors when parsing
2625 programs with very long string literals.
2626
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002627Internals
2628
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002629- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002630 which is called when the interpreter starts up to determine where
2631 the standard library is installed. These vulnerabilities affect all
2632 previous versions of Python and can be exploited by setting very
2633 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2634 setuid Python script, although use of the wrapper in
2635 Misc/setuid-prog.c will eliminate the vulnerability.
2636
2637- Fixed garbage collection bugs in instance creation that were
2638 triggered when errors occurred during initialization. The solution,
2639 applied in cPickle and in PyInstance_New(), is to call
2640 PyObject_GC_Init() after the initialization of the object's
2641 container attributes is complete.
2642
2643- pyexpat adds definitions of PyModule_AddStringConstant and
2644 PyModule_AddObject if the Python version is less than 2.0, which
2645 provides compatibility with PyXML on Python 1.5.2.
2646
2647- If the platform has a bogus definition for LONG_BIT (the number of
2648 bits in a long), an error will be reported at compile time.
2649
2650- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2651 collection crashes and possibly other, unreported crashes.
2652
2653- Fixed a memory leak in _PyUnicode_Fini().
2654
2655Build issues
2656
2657- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002658 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002659 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002660
2661- The mmap.PAGESIZE constant is now initialized using sysconf when
2662 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2663
2664- The md5 file should now compile on all platforms.
2665
2666- The select module now compiles on platforms that do not define
2667 POLLRDNORM and related constants.
2668
2669- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002670 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002671
Jeremy Hylton10921202000-10-09 18:34:12 +00002672- BeOS: A number of changes were made to the build and installation
2673 process. ar-fake now operates on a directory of object files.
2674 dl_export.h is gone, and its macros now appear on the mwcc command
2675 line during build on PPC BeOS.
2676
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002677- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002678 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002679
2680- Cygwin: Support for shared libraries, Tkinter, and sockets.
2681
2682- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2683
2684Tools and other miscellany
2685
2686- Removed debugging prints from main used with freeze.
2687
Tim Peters46446d62000-10-09 21:19:31 +00002688- IDLE auto-indent no longer crashes when it encounters Unicode
2689 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002690
2691What's new in 2.0 beta 2 (since beta 1)?
2692========================================
2693
2694Core language, builtins, and interpreter
2695
Tim Peters482c0212000-09-26 06:33:09 +00002696- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002697 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002698
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002699- Add -h and -V command line options to print the usage message and
2700 Python version number and exit immediately.
2701
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002702- eval() and exec accept Unicode objects as code parameters.
2703
2704- getattr() and setattr() now also accept Unicode objects for the
2705 attribute name, which are converted to strings using the default
2706 encoding before lookup.
2707
2708- Multiplication on string and Unicode now does proper bounds
2709 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2710 string is too long."
2711
2712- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002713 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002714
Jeremy Hylton1b618592000-09-26 05:32:36 +00002715
2716Standard library and extensions
2717
Guido van Rossum5b08f132001-04-16 02:05:23 +00002718- socket module: the OpenSSL code now adds support for RAND_status()
2719 and EGD (Entropy Gathering Device).
2720
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002721- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002722 argument checking; it still takes no arguments.
2723
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002724- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002725
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002726- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002727
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002728- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002729
2730- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002731 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002732
2733- copy: Copy Unicode objects atomically.
2734
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002735- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002736
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002737- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002738
Fred Drake67233bc2000-09-26 16:40:27 +00002739- dbm: Add get() and setdefault() methods to dbm object. Add constant
2740 `library' to module that names the library used. Added doc strings
2741 and method names to error messages. Uses configure to determine
2742 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2743 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002744
2745- distutils: Update to version 0.9.3.
2746
2747- dl: Add several dl.RTLD_ constants.
2748
2749- fpectl: Now supported on FreeBSD.
2750
2751- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2752 found by the collector will be saved in gc.garbage. This is useful
2753 for debugging a program that creates reference cycles.
2754
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002755- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002756 of HTTP class. Do not close socket on zero-length response. Do not
2757 crash when server sends invalid content-length header.
2758
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002759- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002760
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002761- marshal: When reading a short, sign-extend on platforms where shorts
2762 are bigger than 16 bits. When reading a long, repair the unportable
2763 sign extension that was being done for 64-bit machines. (It assumed
2764 that signed right shift sign-extends.)
2765
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002766- operator: Add contains(), invert(), __invert__() as aliases for
2767 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002768
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002769- os: Add support for popen2() and popen3() on all platforms where
2770 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002771
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002772- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002773 clicking on a file in Explorer (or passing the file name to the
2774 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002775
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002776- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002777 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778
2779- pickle: Now raises ValueError when an invalid pickle that contains
2780 a non-string repr where a string repr was expected. This behavior
2781 matches cPickle.
2782
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002783- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002784
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002785- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002786
2787- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002788 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002789 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002790
2791- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793
2794- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002795 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002796 few cycles during startup since the first call to
2797 setdefaultencoding() will initialize the codec registry and the
2798 encodings package.
2799
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002800- socket: Support for size hint in readlines() method of object returned
2801 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002802
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002803- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002804 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002805 is followed by whitespace.
2806
Tim Petersa3a3a032000-11-30 05:22:44 +00002807- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002808
2809- struct: Check ranges for bytes and shorts.
2810
2811- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002812 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002813
2814- Tkinter: Image objects are now guaranteed to have unique ids. Set
2815 event.delta to zero if Tk version doesn't support mousewheel.
2816 Removed some debugging prints.
2817
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002818- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002819
Fred Drake67233bc2000-09-26 16:40:27 +00002820- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002821 which works around a bug in Norton AntiVirus 2000 that leads directly
2822 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002823
2824- xml: New version detection code allows PyXML to override standard
2825 XML package if PyXML version is greater than 0.6.1.
2826
Fred Drake64bb3802000-09-26 16:21:35 +00002827- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2828 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2829 tree only for nodes which are sufficiently interesting to a specific
2830 application. Does not provide the HTML-specific extensions. Still
2831 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002832
Fred Drake64bb3802000-09-26 16:21:35 +00002833- xml.sax: SAX 2 support for Python, including all the handler
2834 interfaces needed to process XML 1.0 compliant XML. Some
2835 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002836
Fred Drake64bb3802000-09-26 16:21:35 +00002837- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2838 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002840
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841C API
2842
2843- Add three new convenience functions for module initialization --
2844 PyModule_AddObject(), PyModule_AddIntConstant(), and
2845 PyModule_AddStringConstant().
2846
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002847- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002848 removed and add #error to Python.h if NULL isn't defined after
2849 #include of stdio.h.
2850
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002851- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002852 backwards compatibility (at the source level) with old extensions.
2853
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002854- A wrapper API was added for signal() and sigaction(). Instead of
2855 either function, always use PyOS_getsig() to get a signal handler
2856 and PyOS_setsig() to set one. A new convenience typedef
2857 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002858
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002859- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002860 internal data buffer and size of a string object -- or the default
2861 encoded version of a Unicode object.
2862
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002863- PyString_Size() and PyString_AsString() accept Unicode objects.
2864
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002865- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002866 exists). INT_MAX and LONG_MAX will always be defined, even if
2867 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002868
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002869- PyFloat_FromString takes a second argument, pend, that was
2870 effectively useless. It is now officially useless but preserved for
2871 backwards compatibility. If the pend argument is not NULL, *pend is
2872 set to NULL.
2873
2874- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2875 for the attribute name. See note on getattr() above.
2876
2877- A few bug fixes to argument processing for Unicode.
2878 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2879 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2880 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002881 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002882
2883- Py_BuildValue accepts B format (for bgen-generated code).
2884
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002885
Jeremy Hylton1b618592000-09-26 05:32:36 +00002886Internals
2887
2888- On Unix, fix code for finding Python installation directory so that
2889 it works when argv[0] is a relative path.
2890
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002891- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002892 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002893 rather than by generating a copy of the object.
2894
Tim Peters482c0212000-09-26 06:33:09 +00002895- Several of the internal Unicode tables are much smaller now, and
2896 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002897
Jeremy Hylton97693b02000-09-26 17:42:51 +00002898- In the garbage collector: Fixed bug in collection of tuples. Fixed
2899 bug that caused some instances to be removed from the container set
2900 while they were still live. Fixed parsing in gc.set_debug() for
2901 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002902
2903- Fixed refcount problem in instance deallocation that only occurred
2904 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2905
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002906- On Windows, getpythonregpath is now protected against null data in
2907 registry key.
2908
2909- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002910 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002911
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002912
Jeremy Hylton1b618592000-09-26 05:32:36 +00002913Build and platform-specific issues
2914
2915- Better support of GNU Pth via --with-pth configure option.
2916
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002917- Python/C API now properly exposed to dynamically-loaded extension
2918 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002919
2920- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2921 Don't define MS_SYNC to be zero when it is undefined. Added missing
2922 prototypes in posixmodule.c.
2923
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002924- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002925 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002926
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002927- Fix largefile support on older NetBSD systems and OpenBSD by adding
2928 define for TELL64.
2929
2930
2931Tools and other miscellany
2932
2933- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2934
2935- freeze: The modulefinder now works with 2.0 opcodes.
2936
Tim Petersa3a3a032000-11-30 05:22:44 +00002937- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002938 Move hackery of sys.argv until after the Tk instance has been
2939 created, which allows the application-specific Tkinter
2940 initialization to be executed if present; also pass an explicit
2941 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002942
Jeremy Hylton1b618592000-09-26 05:32:36 +00002943
2944What's new in 2.0 beta 1?
2945=========================
2946
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002947Source Incompatibilities
2948------------------------
2949
2950None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2951such as single-argument append(), connect() and bind(), and changes to
2952str(long) and repr(float).
2953
2954
2955Binary Incompatibilities
2956------------------------
2957
2958- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2959with Python 2.0; these extensions will have to be rebuilt for Python
29602.0.
2961
2962- On Windows, attempting to import a third party extension built for
2963Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2964can do about this. Check your PYTHONPATH environment variable!
2965
2966- Python bytecode files (*.pyc and *.pyo) are not compatible between
2967releases.
2968
2969
2970Overview of Changes Since 1.6
2971-----------------------------
2972
2973There are many new modules (including brand new XML support through
2974the xml package, and i18n support through the gettext module); a list
2975of all new modules is included below. Lots of bugs have been fixed.
2976
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002977The process for making major new changes to the language has changed
2978since Python 1.6. Enhancements must now be documented by a Python
2979Enhancement Proposal (PEP) before they can be accepted.
2980
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002981There are several important syntax enhancements, described in more
2982detail below:
2983
2984 - Augmented assignment, e.g. x += 1
2985
2986 - List comprehensions, e.g. [x**2 for x in range(10)]
2987
2988 - Extended import statement, e.g. import Module as Name
2989
2990 - Extended print statement, e.g. print >> file, "Hello"
2991
2992Other important changes:
2993
2994 - Optional collection of cyclical garbage
2995
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002996Python Enhancement Proposal (PEP)
2997---------------------------------
2998
2999PEP stands for Python Enhancement Proposal. A PEP is a design
3000document providing information to the Python community, or describing
3001a new feature for Python. The PEP should provide a concise technical
3002specification of the feature and a rationale for the feature.
3003
3004We intend PEPs to be the primary mechanisms for proposing new
3005features, for collecting community input on an issue, and for
3006documenting the design decisions that have gone into Python. The PEP
3007author is responsible for building consensus within the community and
3008documenting dissenting opinions.
3009
3010The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003011
3012Augmented Assignment
3013--------------------
3014
3015This must have been the most-requested feature of the past years!
3016Eleven new assignment operators were added:
3017
Guido van Rossume905e952000-09-05 12:42:46 +00003018 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003019
3020For example,
3021
3022 A += B
3023
3024is similar to
3025
3026 A = A + B
3027
3028except that A is evaluated only once (relevant when A is something
3029like dict[index].attr).
3030
3031However, if A is a mutable object, A may be modified in place. Thus,
3032if A is a number or a string, A += B has the same effect as A = A+B
3033(except A is only evaluated once); but if a is a list, A += B has the
3034same effect as A.extend(B)!
3035
3036Classes and built-in object types can override the new operators in
3037order to implement the in-place behavior; the not-in-place behavior is
3038used automatically as a fallback when an object doesn't implement the
3039in-place behavior. For classes, the method name is derived from the
3040method name for the corresponding not-in-place operator by inserting
3041an 'i' in front of the name, e.g. __iadd__ implements in-place
3042__add__.
3043
3044Augmented assignment was implemented by Thomas Wouters.
3045
3046
3047List Comprehensions
3048-------------------
3049
3050This is a flexible new notation for lists whose elements are computed
3051from another list (or lists). The simplest form is:
3052
3053 [<expression> for <variable> in <sequence>]
3054
Guido van Rossum56db0952000-09-06 23:34:25 +00003055For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003056This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003057
3058You can also add a condition:
3059
3060 [<expression> for <variable> in <sequence> if <condition>]
3061
3062For example, [w for w in words if w == w.lower()] would yield the list
3063of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003064than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003065
3066You can also have nested for loops and more than one 'if' clause. For
3067example, here's a function that flattens a sequence of sequences::
3068
3069 def flatten(seq):
3070 return [x for subseq in seq for x in subseq]
3071
3072 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3073
3074This prints
3075
3076 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3077
3078List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003079Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003080
3081
3082Extended Import Statement
3083-------------------------
3084
3085Many people have asked for a way to import a module under a different
3086name. This can be accomplished like this:
3087
3088 import foo
3089 bar = foo
3090 del foo
3091
3092but this common idiom gets old quickly. A simple extension of the
3093import statement now allows this to be written as follows:
3094
3095 import foo as bar
3096
3097There's also a variant for 'from ... import':
3098
3099 from foo import bar as spam
3100
3101This also works with packages; e.g. you can write this:
3102
3103 import test.regrtest as regrtest
3104
3105Note that 'as' is not a new keyword -- it is recognized only in this
3106context (this is only possible because the syntax for the import
3107statement doesn't involve expressions).
3108
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003109Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003110
3111
3112Extended Print Statement
3113------------------------
3114
3115Easily the most controversial new feature, this extension to the print
3116statement adds an option to make the output go to a different file
3117than the default sys.stdout.
3118
3119For example, to write an error message to sys.stderr, you can now
3120write:
3121
3122 print >> sys.stderr, "Error: bad dog!"
3123
3124As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003125evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003126
3127 print >> None, "Hello world"
3128
3129is equivalent to
3130
3131 print "Hello world"
3132
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003133Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003134
3135
3136Optional Collection of Cyclical Garbage
3137---------------------------------------
3138
3139Python is now equipped with a garbage collector that can hunt down
3140cyclical references between Python objects. It's no replacement for
3141reference counting; in fact, it depends on the reference counts being
3142correct, and decides that a set of objects belong to a cycle if all
3143their reference counts can be accounted for from their references to
3144each other. This devious scheme was first proposed by Eric Tiedemann,
3145and brought to implementation by Neil Schemenauer.
3146
3147There's a module "gc" that lets you control some parameters of the
3148garbage collection. There's also an option to the configure script
3149that lets you enable or disable the garbage collection. In 2.0b1,
3150it's on by default, so that we (hopefully) can collect decent user
3151experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003152performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003153off by default in the final 2.0 release.
3154
3155
3156Smaller Changes
3157---------------
3158
3159A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3160map(None, seq1, seq2, ...) when the sequences have the same length;
3161i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3162the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003163zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003164
3165sys.version_info is a tuple (major, minor, micro, level, serial).
3166
3167Dictionaries have an odd new method, setdefault(key, default).
3168dict.setdefault(key, default) returns dict[key] if it exists; if not,
3169it sets dict[key] to default and returns that value. Thus:
3170
3171 dict.setdefault(key, []).append(item)
3172
3173does the same work as this common idiom:
3174
3175 if not dict.has_key(key):
3176 dict[key] = []
3177 dict[key].append(item)
3178
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003179There are two new variants of SyntaxError that are raised for
3180indentation-related errors: IndentationError and TabError.
3181
3182Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3183escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003184
3185The limits on the size of expressions and file in Python source code
3186have been raised from 2**16 to 2**32. Previous versions of Python
3187were limited because the maximum argument size the Python VM accepted
3188was 2**16. This limited the size of object constructor expressions,
3189e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3190limit was raised thanks to a patch by Charles Waldman that effectively
3191fixes the problem. It is now much more likely that you will be
3192limited by available memory than by an arbitrary limit in Python.
3193
3194The interpreter's maximum recursion depth can be modified by Python
3195programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3196limit is the maximum number of recursive calls that can be made by
3197Python code. The limit exists to prevent infinite recursion from
3198overflowing the C stack and causing a core dump. The default value is
31991000. The maximum safe value for a particular platform can be found
3200by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003201
3202New Modules and Packages
3203------------------------
3204
3205atexit - for registering functions to be called when Python exits.
3206
3207imputil - Greg Stein's alternative API for writing custom import
3208hooks.
3209
3210pyexpat - an interface to the Expat XML parser, contributed by Paul
3211Prescod.
3212
3213xml - a new package with XML support code organized (so far) in three
3214subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3215would fill a volume. There's a special feature whereby a
3216user-installed package named _xmlplus overrides the standard
3217xmlpackage; this is intended to give the XML SIG a hook to distribute
3218backwards-compatible updates to the standard xml package.
3219
3220webbrowser - a platform-independent API to launch a web browser.
3221
3222
Guido van Rossume905e952000-09-05 12:42:46 +00003223Changed Modules
3224---------------
3225
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003226array -- new methods for array objects: count, extend, index, pop, and
3227remove
3228
3229binascii -- new functions b2a_hex and a2b_hex that convert between
3230binary data and its hex representation
3231
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003232calendar -- Many new functions that support features including control
3233over which day of the week is the first day, returning strings instead
3234of printing them. Also new symbolic constants for days of week,
3235e.g. MONDAY, ..., SUNDAY.
3236
3237cgi -- FieldStorage objects have a getvalue method that works like a
3238dictionary's get method and returns the value attribute of the object.
3239
3240ConfigParser -- The parser object has new methods has_option,
3241remove_section, remove_option, set, and write. They allow the module
3242to be used for writing config files as well as reading them.
3243
3244ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003245optionally support the RFC 959 REST command.
3246
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003247gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003248
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003249httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3250the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003251
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003252locale -- implement getdefaultlocale for Win32 and Macintosh
3253
3254marshal -- no longer dumps core when marshaling deeply nested or
3255recursive data structures
3256
3257os -- new functions isatty, seteuid, setegid, setreuid, setregid
3258
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003259os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3260support under Unix.
3261
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003262os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003263
3264os.path -- fix semantics of os.path.commonprefix
3265
3266smtplib -- support for sending very long messages
3267
3268socket -- new function getfqdn()
3269
3270readline -- new functions to read, write and truncate history files.
3271The readline section of the library reference manual contains an
3272example.
3273
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003274select -- add interface to poll system call
3275
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003276shutil -- new copyfileobj function
3277
3278SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3279HTTP server.
3280
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003281Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003282
3283urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003284e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003285
3286whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003287
3288
3289Obsolete Modules
3290----------------
3291
3292None. However note that 1.6 made a whole slew of modules obsolete:
3293stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3294poly, zmod, strop, util, whatsound.
3295
3296
3297Changed, New, Obsolete Tools
3298----------------------------
3299
Tim Peters8b092332000-09-05 20:15:25 +00003300None.
Guido van Rossume905e952000-09-05 12:42:46 +00003301
3302
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003303C-level Changes
3304---------------
3305
3306Several cleanup jobs were carried out throughout the source code.
3307
3308All C code was converted to ANSI C; we got rid of all uses of the
3309Py_PROTO() macro, which makes the header files a lot more readable.
3310
3311Most of the portability hacks were moved to a new header file,
3312pyport.h; several other new header files were added and some old
3313header files were removed, in an attempt to create a more rational set
3314of header files. (Few of these ever need to be included explicitly;
3315they are all included by Python.h.)
3316
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003317Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003318and Win64, especially for the new Intel Itanium processor. Mick also
3319added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003320
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003321The C APIs to return an object's size have been update to consistently
3322use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3323previous versions, the abstract interfaces used PyXXX_Length and the
3324concrete interfaces used PyXXX_Size. The old names,
3325e.g. PyObject_Length, are still available for backwards compatibility
3326at the API level, but are deprecated.
3327
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003328The PyOS_CheckStack function has been implemented on Windows by
3329Fredrik Lundh. It prevents Python from failing with a stack overflow
3330on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003331
3332The GC changes resulted in creation of two new slots on object,
3333tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003334the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003335
3336The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003337C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003338
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003339PyErr_Format has been updated to automatically calculate the size of
3340the buffer needed to hold the formatted result string. This change
3341prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003342
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003343New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003344
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003345PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3346that are the same as their non-Ex counterparts except they take an
3347extra flag argument that tells them to close the file when done.
3348
3349XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003350
Tim Peters8b092332000-09-05 20:15:25 +00003351
3352Windows Changes
3353---------------
3354
3355New popen2/popen3/peopen4 in os module (see Changed Modules above).
3356
3357os.popen is much more usable on Windows 95 and 98. See Microsoft
3358Knowledge Base article Q150956. The Win9x workaround described there
3359is implemented by the new w9xpopen.exe helper in the root of your
3360Python installation. Note that Python uses this internally; it is not
3361a standalone program.
3362
3363Administrator privileges are no longer required to install Python
3364on Windows NT or Windows 2000. If you have administrator privileges,
3365Python's registry info will be written under HKEY_LOCAL_MACHINE.
3366Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003367under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003368uses of Python, but will prevent some advanced uses from working
3369(for example, running a Python script as an NT service, or possibly
3370from CGI).
3371
3372[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3373installer; instead, it installs the needed Tcl/Tk files directly in the
3374Python directory. If you already have a Tcl/Tk installation, this
3375wastes some disk space (about 4 Megs) but avoids problems with
3376conflicting Tcl/Tk installations, and makes it much easier for Python
3377to ensure that Tcl/Tk can find all its files.
3378
3379[This was new in 1.6] The Windows installer now installs by default in
3380\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3381
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003382
3383Updates to the changes between 1.5.2 and 1.6
3384--------------------------------------------
3385
3386The 1.6 NEWS file can't be changed after the release is done, so here
3387is some late-breaking news:
3388
3389New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3390and changes to getlocale() and setlocale().
3391
3392The new module is now enabled per default.
3393
3394It is not true that the encodings codecs cannot be used for normal
3395strings: the string.encode() (which is also present on 8-bit strings
3396!) allows using them for 8-bit strings too, e.g. to convert files from
3397cp1252 (Windows) to latin-1 or vice-versa.
3398
3399Japanese codecs are available from Tamito KAJIYAMA:
3400http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3401
3402
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003403======================================================================