blob: 2e36fc047dcaddd04a1137bdde7d2a857e982209 [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
Anthony Baxter83888952002-04-23 02:11:05 +000067- The bsddb.*open functions can now take 'None' as a filename.
68 This will create a temporary in-memory bsddb that won't be
69 written to disk.
70
Martin v. Löwis06a83e92002-04-14 10:19:44 +000071- posix.mknod was added.
72
Martin v. Löwis2e64c342002-03-27 18:49:02 +000073- The locale module now exposes the C library's gettext interface.
74
Tim Petersfbf74f22002-03-14 19:06:01 +000075- A security hole ("double free") was found in zlib-1.1.3, a popular
76 third party compression library used by some Python modules. The
77 hole was quickly plugged in zlib-1.1.4, and the Windows build of
78 Python now ships with zlib-1.1.4.
79
Martin v. Löwis688357e2002-04-08 21:28:20 +000080- pwd, grp, and resource return enhanced tuples now, with symbolic
81 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000082
Martin v. Löwis99866332002-03-01 10:27:01 +000083- array.array is now a type object. A new format character
84 'u' indicates Py_UNICODE arrays. For those, .tounicode and
85 .fromunicode methods are available. Arrays now support __iadd__
86 and __imul__.
87
Neal Norwitze790eae2002-01-01 21:14:12 +000088- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000089 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
90 is called.
91
Tim Petersaf8446f2001-12-21 21:36:50 +000092Library
93
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +000094- New distutils commands for building packagers were added to
95 support pkgtool on Solaris and swinstall on HP-UX.
96
97- distutils now has a new abstract binary packager base class
98 command/bdist_packager, which simplifies writing packagers.
99 This will hopefully provide the missing bits to encourage
100 people to submit more packagers, e.g. for Debian, FreeBSD
101 and other systems.
102
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000103- The UTF-16, -LE and -BE now raise a NotImplementedError
104 for all calls to .readline(). Previously, they used to just
105 produce garbage or fail with an encoding error -- UTF-16 is
106 a 2-byte encoding and the C lib's line reading APIs don't
107 work well with these.
108
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000109- compileall now supports quiet operation.
110
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000111- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
112 connections.
113
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000114- socket module: the SSL support was broken out of the main
115 _socket module C helper and placed into a new _ssl helper
116 which now gets imported by socket.py if available and working.
117
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000118- encodings package: added aliases for all supported IANA character
119 sets
120
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000121- ftplib: to safeguard the user's privacy, anonymous login will use
122 "anonymous@" as default password, rather than the real user and host
123 name.
124
Fred Drake36736122002-01-10 13:50:31 +0000125- webbrowser: tightened up the command passed to os.system() so that
126 arbitrary shell code can't be executed because a bogus URL was
127 passed in.
128
Tim Peters11bd9942002-02-01 00:52:29 +0000129- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000130 gettext.find an optional all argument. Translations will now fallback
131 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000132
Martin v. Löwis9668b932002-01-12 11:27:42 +0000133- distutils bdist commands now offer a --skip-build option.
134
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000135- warnings.warn now accepts a Warning instance as first argument.
136
Fred Drakefed7e852002-04-04 19:36:15 +0000137- The xml.sax.expatreader.ExpatParser class will no longer create
138 circular references by using itself as the locator that gets passed
139 to the content handler implementation. [SF bug #535474]
140
Tim Petersaf8446f2001-12-21 21:36:50 +0000141Tools/Demos
142
Marc-André Lemburg46260092002-04-04 16:17:11 +0000143- freeze.py now produces binaries which can import shared modules,
144 unlike before when this failed due to missing symbol exports in
145 the generated binary.
146
Tim Petersaf8446f2001-12-21 21:36:50 +0000147Build
148
Tim Peters639295f2002-04-21 07:30:30 +0000149- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
150 say how or when to configure it, or how to turn it off.
151
Martin v. Löwis1142de32002-03-29 16:28:31 +0000152- On Unix, a shared libpython2.3.so can be created with --enable-shared.
153
Tim Peters8deda702002-03-30 10:06:07 +0000154- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
155 preprocessor symbols were eliminated. The internal decisions they
156 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000157
Tim Petersaf8446f2001-12-21 21:36:50 +0000158C API
159
Neil Schemenauer9344b142002-04-12 23:00:08 +0000160- The type of tp_free has been changed from "void (*)(PyObject *)" to
161 "void (*)(void *)".
162
163- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
164
Guido van Rossum0986d822002-04-08 01:38:42 +0000165- A type can now inherit its metatype from its base type. Previously,
166 when PyType_Ready() was called, if ob_type was found to be NULL, it
167 was always set to &PyType_Type; now it is set to base->ob_type,
168 where base is tp_base, defaulting to &PyObject_Type.
169
170- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
171
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000172- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
173 functions will be allocated using pymalloc if it is enabled. These
174 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
175 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
176 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
177 PyCore_* family of APIs have been removed.
178
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000179- The "u#" parser marker will now pass through Unicode object as-is
180 without going through the buffer API.
181
Martin v. Löwis7198a522002-01-01 19:59:11 +0000182- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
183
Tim Peters10a3bb52001-12-25 19:07:38 +0000184- An old #define of ANY as void has been removed from pyport.h. This
185 hasn't been used since Python's pre-ANSI days, and the #define has
186 been marked as obsolete since then. SF bug 495548 says it created
187 conflicts with other packages, so keeping it around wasn't harmless.
188
Tim Petersaf8446f2001-12-21 21:36:50 +0000189- Because Python's magic number scheme broke on January 1st, we decided
190 to stop Python development. Thanks for all the fish!
191
Tim Petersfb05db22002-03-11 00:24:00 +0000192- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000193 scheme to a new one. See Python/import.c for details.
194
Tim Petersaf8446f2001-12-21 21:36:50 +0000195New platforms
196
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000197- GNU/Hurd is now supported.
198
Tim Petersaf8446f2001-12-21 21:36:50 +0000199Tests
200
201Windows
202
Tim Peters08e72952002-04-16 20:48:01 +0000203- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
204 of that has been fixed in the installer (disabled Wise's "delete in-
205 use files" uninstall option).
206
Guido van Rossum181e41a2002-04-06 00:23:25 +0000207- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
208
Tim Peters33187922002-04-04 20:02:04 +0000209- The installer now installs Start menu shortcuts under (the local
210 equivalent of) "All Users" when doing an Admin install.
211
Tim Petersfb05db22002-03-11 00:24:00 +0000212- file.truncate([newsize]) now works on Windows for all newsize values.
213 It used to fail if newsize didn't fit in 32 bits, reflecting a
214 limitation of MS _chsize (which is no longer used).
215
Tim Petersab034fa2002-02-01 11:27:43 +0000216- os.waitpid() is now implemented for Windows, and can be used to block
217 until a specified process exits. This is similar to, but not exactly
218 the same as, os.waitpid() on POSIX systems. If you're waiting for
219 a specific process whose pid was obtained from one of the spawn()
220 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000221 See the docs for details. The docs were changed to clarify that
222 spawn functions return, and waitpid requires, a process handle on
223 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000224
Tim Peters11bd9942002-02-01 00:52:29 +0000225- New tempfile.TemporaryFile implementation for Windows: this doesn't
226 need a TemproraryFileWrapper wrapper anymore, and should be immune
227 to a nasty problem: before 2.3, if you got a temp file on Windows, it
228 got wrapped in an object whose close() method first closed the
229 underlying file, then deleted the file. This usually worked fine.
230 However, the spawn family of functions on Windows create (at a low C
231 level) the same set of open files in the spawned process Q as were
232 open in the spawning process P. If a temp file f was among them, then
233 doing f.close() in P first closed P's C-level file handle on f, but Q's
234 C-level file handle on f remained open, so the attempt in P to delete f
235 blew up with a "Permission denied" error (Windows doesn't allow
236 deleting open files). This was surprising, subtle, and difficult to
237 work around.
238
239- The os module now exports all the symbolic constants usable with the
240 low-level os.open() on Windows: the new constants in 2.3 are
241 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
242 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
243 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
244 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
245 (so specify both if you want both; note that neither is useful unless
246 specified with O_CREAT too).
247
Tim Petersaf8446f2001-12-21 21:36:50 +0000248Mac
249
250
Tim Peters909c0912001-12-14 23:16:18 +0000251What's New in Python 2.2 final?
252Release date: 21-Dec-2001
253===============================
254
255Type/class unification and new-style classes
256
Barry Warsaw52acb492001-12-21 20:04:22 +0000257- pickle.py, cPickle: allow pickling instances of new-style classes
258 with a custom metaclass.
259
Tim Peters909c0912001-12-14 23:16:18 +0000260Core and builtins
261
Barry Warsaw52acb492001-12-21 20:04:22 +0000262- weakref proxy object: when comparing, unwrap both arguments if both
263 are proxies.
264
Tim Peters909c0912001-12-14 23:16:18 +0000265Extension modules
266
Barry Warsaw52acb492001-12-21 20:04:22 +0000267- binascii.b2a_base64(): fix a potential buffer overrun when encoding
268 very short strings.
269
270- cPickle: the obscure "fast" mode was suspected of causing stack
271 overflows on the Mac. Hopefully fixed this by setting the recursion
272 limit much smaller. If the limit is too low (it only affects
273 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
274 when compiling cPickle.c (or in pyconfig.h).
275
Tim Peters909c0912001-12-14 23:16:18 +0000276Library
277
Barry Warsaw52acb492001-12-21 20:04:22 +0000278- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
279 close or delete time).
280
281- rfc822.py: fixed a bug where the address '<>' was converted to None
282 instead of an empty string (also fixes the email.Utils module).
283
284- xmlrpclib.py: version 1.0.0; uses precision for doubles.
285
286- test suite: the pickle and cPickle tests were not executing any code
287 when run from the standard regresssion test.
288
Tim Peters909c0912001-12-14 23:16:18 +0000289Tools/Demos
290
291Build
292
293C API
294
295New platforms
296
297Tests
298
299Windows
300
Barry Warsaw52acb492001-12-21 20:04:22 +0000301- distutils package: fixed broken Windows installers (bdist_wininst).
302
303- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
304 instances are deleted at process exit time.
305
306- socket.py: prevent mysterious warnings when socket instances are
307 deleted at process exit time.
308
309- posixmodule.c: fix a Windows crash with stat() of a filename ending
310 in backslash.
311
Tim Peters909c0912001-12-14 23:16:18 +0000312Mac
313
Barry Warsaw52acb492001-12-21 20:04:22 +0000314- The Carbon toolbox modules have been upgraded to Universal Headers
315 3.4, and experimental CoreGraphics and CarbonEvents modules have
316 been added. All only for framework-enabled MacOSX.
317
Tim Peters909c0912001-12-14 23:16:18 +0000318
Tim Peters6272dfd2001-12-13 19:34:00 +0000319What's New in Python 2.2c1?
320Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000321===========================
322
323Type/class unification and new-style classes
324
Barry Warsaw06557452001-12-14 20:47:12 +0000325- Guido's tutorial introduction to the new type/class features has
326 been extensively updated. See
327
328 http://www.python.org/2.2/descrintro.html
329
330 That remains the primary documentation in this area.
331
Guido van Rossum33bab012001-12-05 22:45:48 +0000332- Fixed a leak: instance variables declared with __slots__ were never
333 deleted!
334
Guido van Rossum4b800852001-12-03 00:54:52 +0000335- The "delete attribute" method of descriptor objects is called
336 __delete__, not __del__. In previous releases, it was mistakenly
337 called __del__, which created an unfortunate overloading condition
338 with finalizers. (The "get attribute" and "set attribute" methods
339 are still called __get__ and __set__, respectively.)
340
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000341- Some subtle issues with the super built-in were fixed:
342
343 (a) When super itself is subclassed, its __get__ method would still
344 return an instance of the base class (i.e., of super).
345
346 (b) super(C, C()).__class__ would return C rather than super. This
347 is confusing. To fix this, I decided to change the semantics of
348 super so that it only applies to code attributes, not to data
349 attributes. After all, overriding data attributes is not
350 supported anyway.
351
352 (c) The __get__ method didn't check whether the argument was an
353 instance of the type used in creation of the super instance.
354
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000355- Previously, hash() of an instance of a subclass of a mutable type
356 (list or dictionary) would return some value, rather than raising
357 TypeError. This has been fixed. Also, directly calling
358 dict.__hash__ and list.__hash__ now raises the same TypeError
359 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000360
Guido van Rossumd331cb52001-12-05 19:46:42 +0000361- New-style objects now support deleting their __dict__. This is for
362 all intents and purposes equivalent to assigning a brand new empty
363 dictionary, but saves space if the object is not used further.
364
Tim Petersb3c9af12001-11-17 00:21:57 +0000365Core and builtins
366
Tim Peters3caca232001-12-06 06:23:26 +0000367- -Qnew now works as documented in PEP 238: when -Qnew is passed on
368 the command line, all occurrences of "/" use true division instead
369 of classic division. See the PEP for details. Note that "all"
370 means all instances in library and 3rd-party modules, as well as in
371 your own code. As the PEP says, -Qnew is intended for use only in
372 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000373 Note that test_coercion.py in the standard Python test suite fails
374 under -Qnew; this is expected, and won't be repaired until true
375 division becomes the default (in the meantime, test_coercion is
376 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000377
Fred Drake6c01e252001-12-14 17:08:12 +0000378- complex() now only allows the first argument to be a string
379 argument, and raises TypeError if either the second arg is a string
380 or if the second arg is specified when the first is a string.
381
Tim Petersb3c9af12001-11-17 00:21:57 +0000382Extension modules
383
Martin v. Löwis560da622001-11-24 09:24:51 +0000384- gc.get_referents was renamed to gc.get_referrers.
385
Tim Petersb3c9af12001-11-17 00:21:57 +0000386Library
387
Tim Peters25059d32001-12-07 20:35:43 +0000388- Functions in the os.spawn() family now release the global interpreter
389 lock around calling the platform spawn. They should always have done
390 this, but did not before 2.2c1. Multithreaded programs calling
391 an os.spawn function with P_WAIT will no longer block all Python threads
392 until the spawned program completes. It's possible that some programs
393 relies on blocking, although more likely by accident than by design.
394
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000395- webbrowser defaults to netscape.exe on OS/2 now.
396
Martin v. Löwis652e1912001-11-25 14:50:56 +0000397- Tix.ResizeHandle exposes detach_widget, hide, and show.
398
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000399- The charset alias windows_1252 has been added.
400
Barry Warsaw06557452001-12-14 20:47:12 +0000401- types.StringTypes is a tuple containing the defined string types;
402 usually this will be (str, unicode), but if Python was compiled
403 without Unicode support it will be just (str,).
404
405- The pulldom and minidom modules were synchronized to PyXML.
406
Tim Petersb3c9af12001-11-17 00:21:57 +0000407Tools/Demos
408
Barry Warsaw06557452001-12-14 20:47:12 +0000409- A new script called Tools/scripts/google.py was added, which fires
410 off a search on Google.
411
Tim Petersb3c9af12001-11-17 00:21:57 +0000412Build
413
Barry Warsaw06557452001-12-14 20:47:12 +0000414- Note that release builds of Python should arrange to define the
415 preprocessor symbol NDEBUG on the command line (or equivalent).
416 In the 2.2 pre-release series we tried to define this by magic in
417 Python.h instead, but it proved to cause problems for extension
418 authors. The Unix, Windows and Mac builds now all define NDEBUG in
419 release builds via cmdline (or equivalent) instead. Ports to
420 other platforms should do likewise.
421
Jack Jansen1999ef42001-12-06 21:47:20 +0000422- It is no longer necessary to use --with-suffix when building on a
423 case-insensitive file system (such as Mac OS X HFS+). In the build
424 directory an extension is used, but not in the installed python.
425
Tim Petersb3c9af12001-11-17 00:21:57 +0000426C API
427
Tim Petersf582b822001-12-11 18:51:08 +0000428- New function PyDict_MergeFromSeq2() exposes the builtin dict
429 constructor's logic for updating a dictionary from an iterable object
430 producing key-value pairs.
431
Tim Peterscffed4b2001-11-29 03:26:37 +0000432- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000433 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000434 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
435 dump core in some bad cases. This has been repaired. As a result,
436 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
437 previously went unchallenged.
438
Tim Petersb3c9af12001-11-17 00:21:57 +0000439New platforms
440
441Tests
442
443Windows
444
445Mac
446
Jack Jansenffa260f2001-12-06 21:14:00 +0000447- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
448 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000449
Barry Warsaw06557452001-12-14 20:47:12 +0000450- Changed logic for finding python home in Mac OS X framework Pythons.
451 Now sys.executable points to the executable again, in stead of to
452 the shared library. The latter is used only for locating the python
453 home.
454
455
Tim Peters84362bc2001-10-19 17:55:30 +0000456What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000457Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000458===========================
459
460Type/class unification and new-style classes
461
Guido van Rossum3d27df02001-11-15 20:27:54 +0000462- Multiple inheritance mixing new-style and classic classes in the
463 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000464
465 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000466 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000467
468 The MRO (method resolution order) for each base class is respected
469 according to its kind, but the MRO for the derived class is computed
470 using new-style MRO rules if any base clase is a new-style class.
471 This needs to be documented.
472
Tim Petersa427a2b2001-10-29 22:25:45 +0000473- The new builtin dictionary() constructor, and dictionary type, have
474 been renamed to dict. This reflects a decade of common usage.
475
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000476- dict() now accepts an iterable object producing 2-sequences. For
477 example, dict(d.items()) == d for any dictionary d. The argument,
478 and the elements of the argument, can be any iterable objects.
479
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000480- New-style classes can now have a __del__ method, which is called
481 when the instance is deleted (just like for classic classes).
482
Guido van Rossum12d955c2001-10-26 14:56:06 +0000483- Assignment to object.__dict__ is now possible, for objects that are
484 instances of new-style classes that have a __dict__ (unless the base
485 class forbids it).
486
Guido van Rossumc8e56452001-10-22 00:43:43 +0000487- Methods of built-in types now properly check for keyword arguments
488 (formerly these were silently ignored). The only built-in methods
489 that take keyword arguments are __call__, __init__ and __new__.
490
Guido van Rossum86443212001-10-27 22:28:54 +0000491- The socket function has been converted to a type; see below.
492
Tim Peters84362bc2001-10-19 17:55:30 +0000493Core and builtins
494
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000495- Assignment to __debug__ raises SyntaxError at compile-time. This
496 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000497 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000498
Guido van Rossum12d955c2001-10-26 14:56:06 +0000499- Clarified the error messages for unsupported operands to an operator
500 (like 1 + '').
501
Tim Peters84362bc2001-10-19 17:55:30 +0000502Extension modules
503
Tim Peters5ebfd362001-11-13 23:11:19 +0000504- mmap has a new keyword argument, "access", allowing a uniform way for
505 both Windows and Unix users to create read-only, write-through and
506 copy-on-write memory mappings. This was previously possible only on
507 Unix. A new keyword argument was required to support this in a
508 uniform way because the mmap() signuatures had diverged across
509 platforms. Thanks to Jay T Miller for repairing this!
510
Tim Peters169ded02001-11-03 19:57:21 +0000511- By default, the gc.garbage list now contains only those instances in
512 unreachable cycles that have __del__ methods; in 2.1 it contained all
513 instances in unreachable cycles. "Instances" here has been generalized
514 to include instances of both new-style and old-style classes.
515
Guido van Rossum12d955c2001-10-26 14:56:06 +0000516- The socket module defines a new method for socket objects,
517 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000518 send() until all data has been sent. Also, the socket function has
519 been converted to a subclassable type, like list and tuple (etc.)
520 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000521
522- Various bugfixes to the curses module. There is now a test suite
523 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000524
Guido van Rossum692adf12001-10-30 03:03:03 +0000525- binascii.b2a_base64 no longer places an arbitrary restriction of 57
526 bytes on its input.
527
Tim Peters84362bc2001-10-19 17:55:30 +0000528Library
529
Tim Peters5ebfd362001-11-13 23:11:19 +0000530- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000531 convenience function.
532
Tim Peters75335872001-11-03 19:35:43 +0000533- Symbolic group names in regular expressions must be unique. For
534 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
535 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000536 Python 2.2 detects this error at regexp compilation time;
537 previously, the error went undetected, and results were
538 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
539 pattern.subn() methods have been rewritten in C. Also, an
540 experimental function/method finditer() has been added, which works
541 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000542
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000543- Tix exposes more commands through the classes DirSelectBox,
544 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
545 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
546 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
547
Tim Peters98791af2001-10-23 01:59:54 +0000548- Traceback objects are now scanned by cyclic garbage collection, so
549 cycles created by casual use of sys.exc_info() no longer cause
550 permanent memory leaks (provided garbage collection is enabled).
551
Guido van Rossum49192142001-10-24 20:51:44 +0000552- os.extsep -- a new variable needed by the RISCOS support. It is the
553 separator used by extensions, and is '.' on all platforms except
554 RISCOS, where it is '/'. There is no need to use this variable
555 unless you have a masochistic desire to port your code to RISCOS.
556
Barry Warsaw012852b2001-11-16 16:17:27 +0000557- mimetypes.py has optional support for non-standard, but commonly
558 found types. guess_type() and guess_extension() now accept an
559 optional `strict' flag, defaulting to true, which controls whether
560 recognize non-standard types or not. A few non-standard types we
561 know about have been added. Also, when run as a script, there are
562 new -l and -e options.
563
564- statcache is now deprecated.
565
566- email.Utils.formatdate() now produces the preferred RFC 2822 style
567 dates with numeric timezones (it used to produce obsolete dates
568 hard coded to "GMT" timezone). An optional `localtime' flag is
569 added to produce dates in the local timezone, with daylight savings
570 time properly taken into account.
571
572- In pickle and cPickle, instead of masking errors in load() by
573 transforming them into SystemError, we let the original exception
574 propagate out. Also, implement support for __safe_for_unpickling__
575 in pickle, as it already was supported in cPickle.
576
Tim Peters84362bc2001-10-19 17:55:30 +0000577Tools/Demos
578
579Build
580
Barry Warsaw012852b2001-11-16 16:17:27 +0000581- The dbm module is built using libdb1 if available. The bsddb module
582 is built with libdb3 if available.
583
584- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
585
Tim Peters84362bc2001-10-19 17:55:30 +0000586C API
587
Tim Peters1fc240e2001-10-26 05:06:50 +0000588- New function PySequence_Fast_GET_SIZE() returns the size of a non-
589 NULL result from PySequence_Fast(), more quickly than calling
590 PySequence_Size().
591
Barry Warsaw012852b2001-11-16 16:17:27 +0000592- New argument unpacking function PyArg_UnpackTuple() added.
593
594- New functions PyObject_CallFunctionObjArgs() and
595 PyObject_CallMethodObjArgs() have been added to make it more
596 convenient and efficient to call functions and methods from C.
597
598- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
599 possible that this will propagate errors it didn't before.
600
601- New function PyObject_CheckReadBuffer(), which returns true if its
602 argument supports the single-segment readable buffer interface.
603
Tim Peters84362bc2001-10-19 17:55:30 +0000604New platforms
605
Guido van Rossum86443212001-10-27 22:28:54 +0000606- We've finally confirmed that this release builds on HP-UX 11.00,
607 *with* threads, and passes the test suite.
608
Tim Peters7a33d8b2001-11-05 02:51:07 +0000609- Thanks to a series of patches from Michael Muller, Python may build
610 again under OS/2 Visual Age C++.
611
Guido van Rossum49192142001-10-24 20:51:44 +0000612- Updated RISCOS port by Dietmar Schwertberger.
613
Tim Peters84362bc2001-10-19 17:55:30 +0000614Tests
615
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000616- Added a test script for the curses module. It isn't run automatically;
617 regrtest.py must be run with '-u curses' to enable it.
618
Tim Peters84362bc2001-10-19 17:55:30 +0000619Windows
620
Barry Warsaw012852b2001-11-16 16:17:27 +0000621Mac
622
623- PythonScript has been moved to unsupported and is slated to be
624 removed completely in the next release.
625
626- It should now be possible to build applets that work on both OS9 and
627 OSX.
628
629- The core is now linked with CoreServices not Carbon; as a side
630 result, default 8bit encoding on OSX is now ASCII.
631
632- Python should now build on OSX 10.1.1
633
Tim Peters84362bc2001-10-19 17:55:30 +0000634
Tim Petersabf925f2001-09-28 21:53:42 +0000635What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000636Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000637===========================
638
639Type/class unification and new-style classes
640
Guido van Rossum687ae002001-10-15 22:03:32 +0000641- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000642 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000643 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000644 remains: the __dict__ of a new-style class is a read-only proxy; you
645 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000646 __defined__ attribute of new-style types no longer exists, for lack
647 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000648 future a __cache__ may be resurrected with a similar function, if I
649 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000650
Tim Peters1c9ca872001-10-04 06:43:12 +0000651- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
652 always returned None, even when there was a class docstring).
653
654- doctest now finds and runs docstrings attached to new-style classes,
655 class methods, static methods, and properties.
656
Guido van Rossum9074ef62001-10-16 21:34:49 +0000657Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000658
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000659- A very subtle syntactical pitfall in list comprehensions was fixed.
660 For example: [a+b for a in 'abc', for b in 'def']. The comma in
661 this example is a mistake. Previously, this would silently let 'a'
662 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
663 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
664 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
665 Note that [a for a in <singleton>] is a convoluted way to say
666 [<singleton>] anyway, so it's not like any expressiveness is lost.
667
Guido van Rossum9074ef62001-10-16 21:34:49 +0000668- getattr(obj, name, default) now only catches AttributeError, as
669 documented, rather than returning the default value for all
670 exceptions (which could mask bugs in a __getattr__ hook, for
671 example).
672
Fred Drakecb7a6b52001-10-22 18:41:51 +0000673- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000674 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000675 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000676 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000677
Guido van Rossum1c486092001-10-19 02:05:35 +0000678- unicode(obj) now behaves more like str(obj), accepting arbitrary
679 objects, and calling a __unicode__ method if it exists.
680 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000681 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000682
Barry Warsawf6fb1712001-10-19 05:35:40 +0000683- isinstance() now allows any object as the first argument and a
684 class, a type or something with a __bases__ tuple attribute for the
685 second argument. The second argument may also be a tuple of a
686 class, type, or something with __bases__, in which case isinstance()
687 will return true if the first argument is an instance of any of the
688 things contained in the second argument tuple. E.g.
689
690 isinstance(x, (A, B))
691
692 returns true if x is an instance of A or B.
693
Guido van Rossum9074ef62001-10-16 21:34:49 +0000694Extension modules
695
696- thread.start_new_thread() now returns the thread ID (previously None).
697
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000698- binascii has now two quopri support functions, a2b_qp and b2a_qp.
699
Guido van Rossumc524d952001-10-19 01:31:59 +0000700- readline now supports setting the startup_hook and the
701 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000702
Guido van Rossumc524d952001-10-19 01:31:59 +0000703- os and posix supports chroot(), setgroups() and unsetenv() where
704 available. The stat(), fstat(), statvfs() and fstatvfs() functions
705 now return "pseudo-sequences" -- the various fields can now be
706 accessed as attributes (e.g. os.stat("/").st_mtime) but for
707 backwards compatibility they also behave as a fixed-length sequence.
708 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000709 attributes.
710
711- time: localtime(), gmtime() and strptime() now return a
712 pseudo-sequence similar to the os.stat() return value, with
713 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000714
Guido van Rossum9074ef62001-10-16 21:34:49 +0000715- Decompression objects in the zlib module now accept an optional
716 second parameter to decompress() that specifies the maximum amount
717 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000718
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000719- optional SSL support in the socket module now exports OpenSSL
720 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
721 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000722 automatically seed its PRNG. Also, the keyfile and certfile
723 arguments to socket.ssl() are now optional.
724
725- posixmodule (and by extension, the os module on POSIX platforms) now
726 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000727
Guido van Rossum9074ef62001-10-16 21:34:49 +0000728Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000729
Tim Peters7402f792001-10-02 03:53:41 +0000730- doctest now excludes functions and classes not defined by the module
731 being tested, thanks to Tim Hochberg.
732
Fred Drakecb7a6b52001-10-22 18:41:51 +0000733- HotShot, a new profiler implemented using a C-based callback, has
734 been added. This substantially reduces the overhead of profiling,
735 but it is still quite preliminary. Support modules and
736 documentation will be added in upcoming releases (before 2.2 final).
737
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000738- profile now produces correct output in situations where an exception
739 raised in Python is cleared by C code (e.g. hasattr()). This used
740 to cause wrong output, including spurious claims of recursive
741 functions and attribution of time spent to the wrong function.
742
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000743 The code and documentation for the derived OldProfile and HotProfile
744 profiling classes was removed. The code hasn't worked for years (if
745 you tried to use them, they raised exceptions). OldProfile
746 intended to reproduce the behavior of the profiler Python used more
747 than 7 years ago, and isn't interesting anymore. HotProfile intended
748 to provide a faster profiler (but producing less information), and
749 that's a worthy goal we intend to meet via a different approach (but
750 without losing information).
751
Tim Peterscce092d2001-10-09 05:31:56 +0000752- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000753 a much better system-specific calibration constant. The constant can
754 now be specified in an instance constructor, or as a Profile class or
755 instance variable, instead of by editing profile.py's source code.
756 Calibration must still be done manually (see the docs for the profile
757 module).
758
759 Note that Profile.calibrate() must be overriden by subclasses.
760 Improving the accuracy required exploiting detailed knowledge of
761 profiler internals; the earlier method abstracted away the details
762 and measured a simplified model instead, but consequently computed
763 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000764
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000765- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000766 which indicates whether output is intended for the header 'Q'
767 encoding.
768
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000769- The SocketServer.ThreadingMixIn class now closes the request after
770 finish_request() returns. (Not when it errors out though.)
771
Barry Warsawf6fb1712001-10-19 05:35:40 +0000772- The nntplib module's NNTP.body() method has grown a `file' argument
773 to allow saving the message body to a file.
774
775- The email package has added a class email.Parser.HeaderParser which
776 only parses headers and does not recurse into the message's body.
777 Also, the module/class MIMEAudio has been added for representing
778 audio data (contributed by Anthony Baxter).
779
780- ftplib should be able to handle files > 2GB.
781
782- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
783 ON, and OFF.
784
Fred Drakecb7a6b52001-10-22 18:41:51 +0000785- xml.dom.minidom NodeList objects now support the length attribute
786 and item() method as required by the DOM specifications.
787
Guido van Rossumed554f62001-10-02 23:15:37 +0000788Tools/Demos
789
790- Demo/dns was removed. It no longer serves any purpose; a package
791 derived from it is now maintained by Anthony Baxter, see
792 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000793
Barry Warsawf6fb1712001-10-19 05:35:40 +0000794- The freeze tool has been made more robust, and two new options have
795 been added: -X and -E.
796
Tim Petersabf925f2001-09-28 21:53:42 +0000797Build
798
Barry Warsawf6fb1712001-10-19 05:35:40 +0000799- configure will use CXX in LINKCC if CXX is used to build main() and
800 the system requires to link a C++ main using the C++ compiler.
801
Tim Petersabf925f2001-09-28 21:53:42 +0000802C API
803
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000804- The documentation for the tp_compare slot is updated to require that
805 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
806 not correct. This is not yet enforced but will be enforced in
807 Python 2.3; even later, we may use -2 to indicate errors and +2 for
808 "NotImplemented". Right now, -1 should be used for an error return.
809
Tim Petersd38b1c72001-09-30 05:09:37 +0000810- PyLong_AsLongLong() now accepts int (as well as long) arguments.
811 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
812 as long) arguments.
813
Guido van Rossum3c288632001-10-16 21:13:49 +0000814- PyThread_start_new_thread() now returns a long int giving the thread
815 ID, if one can be calculated; it returns -1 for error, 0 if no
816 thread ID is calculated (this is an incompatible change, but only
817 the thread module used this API). This code has only really been
818 tested on Linux and Windows; other platforms please beware (and
819 report any bugs or strange behavior).
820
Guido van Rossum1c486092001-10-19 02:05:35 +0000821- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
822 input.
823
Tim Petersabf925f2001-09-28 21:53:42 +0000824New platforms
825
826Tests
827
828Windows
829
Tim Peters04cf1d32001-10-09 22:39:40 +0000830- Installer: If you install IDLE, and don't disable file-extension
831 registration, a new "Edit with IDLE" context (right-click) menu entry
832 is created for .py and .pyw files.
833
Tim Peters1ce3cf72001-10-01 17:58:40 +0000834- The signal module now supports SIGBREAK on Windows, thanks to Steven
835 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
836 action remains to call Win32 ExitProcess(). This can be changed via
837 signal.signal(). For example:
838
839 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
840 # (SIGINT) behavior.
841 import signal
842 signal.signal(signal.SIGBREAK,
843 signal.default_int_handler)
844
845 try:
846 while 1:
847 pass
848 except KeyboardInterrupt:
849 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
850 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
851 # program without the possibility for any Python-level cleanup).
852 print "Clean exit"
853
Tim Petersabf925f2001-09-28 21:53:42 +0000854
Tim Petersb07352e2001-09-08 01:25:47 +0000855What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000856Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000857===========================
858
Guido van Rossum808eea72001-09-25 04:15:41 +0000859Type/class unification and new-style classes
860
861- pydoc and inspect are now aware of new-style classes;
862 e.g. help(list) at the interactive prompt now shows proper
863 documentation for all operations on list objects.
864
865- Applications using Jim Fulton's ExtensionClass module can now safely
866 be used with Python 2.2. In particular, Zope 2.4.1 now works with
867 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
868 examples also work again. It is hoped that Gtk and Boost also work
869 with 2.2a4 and beyond. (If you can confirm this, please write
870 webmaster@python.org; if there are still problems, please open a bug
871 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000872
Tim Peters66c1a522001-09-24 21:17:50 +0000873- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
874 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
875 in the constructed property object. fget, fset and fdel weren't
876 discoverable from Python in 2.2a3. __doc__ is new, and allows to
877 associate a docstring with a property.
878
Guido van Rossum808eea72001-09-25 04:15:41 +0000879- Comparison overloading is now more completely implemented. For
880 example, a str subclass instance can properly be compared to a str
881 instance, and it can properly overload comparison. Ditto for most
882 other built-in object types.
883
884- The repr() of new-style classes has changed; instead of <type
885 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
886 *except* for built-in types, which are still rendered as <type
887 'Foo'> (to avoid upsetting existing code that might parse or
888 otherwise rely on repr() of certain type objects).
889
890- The repr() of new-style objects is now always <Foo object at XXX>;
891 previously, it was sometimes <Foo instance at XXX>.
892
893- For new-style classes, what was previously called __getattr__ is now
894 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000895 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000896 one in classic classes is defined which is called only if regular
897 attribute access raises AttributeError; to catch *all* attribute
898 access, you can use __getattribute__ (for new-style classes). If
899 both are defined, __getattribute__ is called first, and if it raises
900 AttributeError, __getattr__ is called.
901
902- The __class__ attribute of new-style objects can be assigned to.
903 The new class must have the same C-level object layout as the old
904 class.
905
906- The builtin file type can be subclassed now. In the usual pattern,
907 "file" is the name of the builtin type, and file() is a new builtin
908 constructor, with the same signature as the builtin open() function.
909 file() is now the preferred way to open a file.
910
911- Previously, __new__ would only see sequential arguments passed to
912 the type in a constructor call; __init__ would see both sequential
913 and keyword arguments. This made no sense whatsoever any more, so
914 now both __new__ and __init__ see all arguments.
915
916- Previously, hash() applied to an instance of a subclass of str or
917 unicode always returned 0. This has been repaired.
918
919- Previously, an operation on an instance of a subclass of an
920 immutable type (int, long, float, complex, tuple, str, unicode),
921 where the subtype didn't override the operation (and so the
922 operation was handled by the builtin type), could return that
923 instance instead a value of the base type. For example, if s was of
924 a str sublass type, s[:] returned s as-is. Now it returns a str
925 with the same value as s.
926
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000927- Provisional support for pickling new-style objects has been added.
928
Guido van Rossum808eea72001-09-25 04:15:41 +0000929Core
930
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000931- file.writelines() now accepts any iterable object producing strings.
932
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000933- PyUnicode_FromEncodedObject() now works very much like
934 PyObject_Str(obj) in that it tries to use __str__/tp_str
935 on the object if the object is not a string or buffer. This
936 makes unicode() behave like str() when applied to non-string/buffer
937 objects.
938
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000939- PyFile_WriteObject now passes Unicode objects to the file's write
940 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000941 of a print statement must support Unicode objects, i.e. they must
942 at least convert them into ASCII strings.
943
Guido van Rossum624c8af2001-09-18 15:21:04 +0000944- Thread scheduling on Solaris should be improved; it is no longer
945 necessary to insert a small sleep at the start of a thread in order
946 to let other runnable threads be scheduled.
947
Tim Petersb07352e2001-09-08 01:25:47 +0000948Library
949
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000950- StringIO.StringIO instances and cStringIO.StringIO instances support
951 read character buffer compatible objects for their .write() methods.
952 These objects are converted to strings and then handled as such
953 by the instances.
954
Barry Warsaw2f600732001-09-24 04:28:10 +0000955- The "email" package has been added. This is basically a port of the
956 mimelib package <http://sf.net/projects/mimelib> with API changes
957 and some implementations updated to use iterators and generators.
958
Tim Peters8a9c2842001-09-22 21:30:22 +0000959- difflib.ndiff() and difflib.Differ.compare() are generators now. This
960 restores the ability of Tools/scripts/ndiff.py to start producing output
961 before the entire comparison is complete.
962
Barry Warsaw58b072d2001-09-22 04:44:21 +0000963- StringIO.StringIO instances and cStringIO.StringIO instances support
964 iteration just like file objects (i.e. their .readline() method is
965 called for each iteration until it returns an empty string).
966
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000967- The codecs module has grown four new helper APIs to access
968 builtin codecs: getencoder(), getdecoder(), getreader(),
969 getwriter().
970
Guido van Rossum624c8af2001-09-18 15:21:04 +0000971- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
972 simplifies writing XML RPC servers.
973
Barry Warsaw647d5e82001-09-28 17:01:02 +0000974- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000975 after interpretation of symbolic links. On non-Unix systems, this
976 is an alias for os.path.abspath().
977
Tim Peters16a77ad2001-09-08 04:00:12 +0000978- operator.indexOf() (PySequence_Index() in the C API) now works with any
979 iterable object.
980
Guido van Rossum624c8af2001-09-18 15:21:04 +0000981- smtplib now supports various authentication and security features of
982 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000983
Guido van Rossum624c8af2001-09-18 15:21:04 +0000984- hmac: a new module implementing keyed hashing for message
985 authentication.
986
987- mimetypes now recognizes more extensions and file types. At the
988 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000989
Guido van Rossum624c8af2001-09-18 15:21:04 +0000990- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000991 Python 2.2 bytecode generation. It has also been promoted from a
992 Tool to a standard library package. (Tools/compiler still exists as
993 a sample driver.)
994
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000995Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000996
Tim Petersb07352e2001-09-08 01:25:47 +0000997Build
998
Guido van Rossum624c8af2001-09-18 15:21:04 +0000999- Large file support (LFS) is now automatic when the platform supports
1000 it; no more manual configuration tweaks are needed. On Linux, at
1001 least, it's possible to have a system whose C library supports large
1002 files but whose kernel doesn't; in this case, large file support is
1003 still enabled but doesn't do you any good unless you upgrade your
1004 kernel or share your Python executable with another system whose
1005 kernel has large file support.
1006
1007- The configure script now supplies plausible defaults in a
1008 cross-compilation environment. This doesn't mean that the supplied
1009 values are always correct, or that cross-compilation now works
1010 flawlessly -- but it's a first step (and it shuts up most of
1011 autoconf's warnings about AC_TRY_RUN).
1012
1013- The Unix build is now a bit less chatty, courtesy of the parser
1014 generator. The build is completely silent (except for errors) when
1015 using "make -s", thanks to a -q option to setup.py.
1016
Tim Petersb07352e2001-09-08 01:25:47 +00001017C API
1018
Guido van Rossum624c8af2001-09-18 15:21:04 +00001019- The "structmember" API now supports some new flag bits to deny read
1020 and/or write access to attributes in restricted execution mode.
1021
Tim Petersb07352e2001-09-08 01:25:47 +00001022New platforms
1023
Guido van Rossum624c8af2001-09-18 15:21:04 +00001024- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1025 (http://familiar.handhelds.org).
1026
Tim Petersb07352e2001-09-08 01:25:47 +00001027Tests
1028
Tim Peters8a9c2842001-09-22 21:30:22 +00001029- The "classic" standard tests, which work by comparing stdout to
1030 an expected-output file under Lib/test/output/, no longer stop at
1031 the first mismatch. Instead the test is run to completion, and a
1032 variant of ndiff-style comparison is used to report all differences.
1033 This is much easier to understand than the previous style of reporting.
1034
1035- The unittest-based standard tests now use regrtest's test_main()
1036 convention, instead of running as a side-effect of merely being
1037 imported. This allows these tests to be run in more natural and
1038 flexible ways as unittests, outside the regrtest framework.
1039
1040- regrtest.py is much better integrated with unittest and doctest now,
1041 especially in regard to reporting errors.
1042
Tim Petersb07352e2001-09-08 01:25:47 +00001043Windows
1044
Guido van Rossum624c8af2001-09-18 15:21:04 +00001045- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001046 that support it (NTFS under Windows 2000). See "What's New in
1047 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001048
Tim Petersb07352e2001-09-08 01:25:47 +00001049
Tim Petersedc99312001-08-22 21:36:50 +00001050What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001051Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001052===========================
1053
1054Core
1055
Tim Peters9fffa3e2001-09-04 05:14:19 +00001056- Conversion of long to float now raises OverflowError if the long is too
1057 big to represent as a C double.
1058
Tim Peters32f453e2001-09-03 08:35:41 +00001059- The 3-argument builtin pow() no longer allows a third non-None argument
1060 if either of the first two arguments is a float, or if both are of
1061 integer types and the second argument is negative (in which latter case
1062 the arguments are converted to float, so this is really the same
1063 restriction).
1064
Tim Peters5d2b77c2001-09-03 05:47:38 +00001065- The builtin dir() now returns more information, and sometimes much
1066 more, generally naming all attributes of an object, and all attributes
1067 reachable from the object via its class, and from its class's base
1068 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1069 an empty list. In 2.2a3,
1070
1071 >>> dir([])
1072 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1073 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1074 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1075 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1076 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1077 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1078 'reverse', 'sort']
1079
1080 dir(module) continues to return only the module's attributes, though.
1081
Tim Petersbdee63f2001-09-02 03:40:59 +00001082- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001083 than raising OverflowError. This is a partial implementation of PEP
1084 237. You can use -Wdefault::OverflowWarning to enable a warning for
1085 this situation, and -Werror::OverflowWarning to revert to the old
1086 OverflowError exception.
1087
Guido van Rossum61c345f2001-09-04 03:26:15 +00001088- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001089 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001090 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1091 -Qold, meaning the / operator has its classic meaning and no
1092 warnings are issued. Using -Qwarn issues a run-time warning about
1093 all uses of classic division for int and long arguments; -Qwarnall
1094 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001095 (for use with fixdiv.py).
1096 [Note: the remainder of this paragraph (preserved below) became
1097 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1098 <obsolete>
1099 Using -Qnew is questionable; it turns on new division by default, but
1100 only in the __main__ module. You can usefully combine -Qwarn or
1101 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1102 warns about classic division everywhere else.
1103 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001104
Tim Petersbdee63f2001-09-02 03:40:59 +00001105- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001106 long, float, str, unicode, and tuple. (The types complex, list and
1107 dictionary can also be subclassed; this was introduced earlier.)
1108 Note that restrictions apply when subclassing immutable built-in
1109 types: you can only affect the value of the instance by overloading
1110 __new__. You can add mutable attributes, and the subclass instances
1111 will have a __dict__ attribute, but you cannot change the "value"
1112 (as implemented by the base class) of an immutable subclass instance
1113 once it is created.
1114
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001115- The dictionary constructor now takes an optional argument, a
1116 mapping-like object, and initializes the dictionary from its
1117 (key, value) pairs.
1118
Tim Petersbdee63f2001-09-02 03:40:59 +00001119- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001120 "cooperative super calls" in a multiple inheritance setting. For an
1121 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1122
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001123- A new built-in type, property, has been added. This enables the
1124 creation of "properties". These are attributes implemented by
1125 getter and setter functions (or only one of these for read-only or
1126 write-only attributes), without the need to override __getattr__.
1127 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001128
Tim Petersbdee63f2001-09-02 03:40:59 +00001129- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001130 liberalized, to allow leading zeroes. Examples of literals now
1131 legal that were SyntaxErrors before:
1132
1133 00.0 0e3 0100j 07.5 00000000000000000008.
1134
Tim Petersbdee63f2001-09-02 03:40:59 +00001135- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001136 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1137
Tim Petersedc99312001-08-22 21:36:50 +00001138Library
1139
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001140- telnetlib includes symbolic names for the options, and support for
1141 setting an option negotiation callback.
1142
Tim Petersa40c7932001-09-05 22:36:56 +00001143- The new C standard no longer requires that math libraries set errno to
1144 ERANGE on overflow. For platform libraries that exploit this new
1145 freedom, Python's overflow-checking was wholly broken. A new overflow-
1146 checking scheme attempts to repair that, but may not be reliable on all
1147 platforms (C doesn't seem to provide anything both useful and portable
1148 in this area anymore).
1149
Martin v. Löwis44f86962001-09-05 13:44:54 +00001150- Asynchronous timeout actions are available through the new class
1151 threading.Timer.
1152
Tim Peters78526162001-09-05 00:53:45 +00001153- math.log and math.log10 now return sensible results for even huge
1154 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1155
Tim Petersbdee63f2001-09-02 03:40:59 +00001156- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001157 currently held. See the docs for the imp module.
1158
Tim Petersbdee63f2001-09-02 03:40:59 +00001159- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001160 dumps containing ints written on platforms where Python ints are 8 bytes.
1161 When read on a box where Python ints are 4 bytes, such values are
1162 converted to Python longs.
1163
Tim Petersbdee63f2001-09-02 03:40:59 +00001164- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001165 code objects is no longer allowed. This plugs a security hole.
1166
Steve Purcell6091cd62001-09-06 16:05:17 +00001167- unittest.TestResult instances no longer store references to tracebacks
1168 generated by test failures. This prevents unexpected dangling references
1169 to objects that should be garbage collected between tests.
1170
Tim Petersedc99312001-08-22 21:36:50 +00001171Tools
1172
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001173- Tools/scripts/fixdiv.py has been added which can be used to fix
1174 division operators as per PEP 238.
1175
Tim Petersedc99312001-08-22 21:36:50 +00001176Build
1177
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001178- If you are an adventurous person using Mac OS X you may want to look at
1179 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1180 application, which can be used for experimenting with Carbon or Cocoa.
1181 Discussion of this on pythonmac-sig, please.
1182
Tim Peters7eea37e2001-09-04 22:08:56 +00001183C API
1184
1185- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001186
Tim Peters9fffa3e2001-09-04 05:14:19 +00001187- Note that PyLong_AsDouble can fail! This has always been true, but no
1188 callers checked for it. It's more likely to fail now, because overflow
1189 errors are properly detected now. The proper way to check:
1190
1191 double x = PyLong_AsDouble(some_long_object);
1192 if (x == -1.0 && PyErr_Occurred()) {
1193 /* The conversion failed. */
1194 }
1195
Tim Petersbdee63f2001-09-02 03:40:59 +00001196- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001197 compile but will not participate in GC. To upgrade an extension
1198 module:
1199
1200 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001201
Neil Schemenauer4042c692001-08-30 15:38:01 +00001202 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1203 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001204
Neil Schemenauer4042c692001-08-30 15:38:01 +00001205 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1206 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001207
Neil Schemenauer4042c692001-08-30 15:38:01 +00001208 - remove PyGC_HEAD_SIZE from object size calculations
1209
1210 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1211
Tim Petersbdee63f2001-09-02 03:40:59 +00001212- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001213 These can be used safely to construct string objects from a
1214 sprintf-style format string (similar to the format string supported
1215 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001216
Tim Petersedc99312001-08-22 21:36:50 +00001217New platforms
1218
Tim Petersb7da0902001-09-02 23:01:43 +00001219- Stephen Hansen contributed patches sufficient to get a clean compile
1220 under Borland C (Windows), but he reports problems running it and ran
1221 out of time to complete the port. Volunteers? Expect a MemoryError
1222 when importing the types module; this is probably shallow, and
1223 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001224
Tim Petersedc99312001-08-22 21:36:50 +00001225Tests
1226
1227Windows
1228
Tim Peters6e13a562001-09-06 00:32:15 +00001229- Large file support is now enabled on Win32 platforms as well as on
1230 Win64. This means that, for example, you can use f.tell() and f.seek()
1231 to manipulate files larger than 2 gigabytes (provided you have enough
1232 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001233 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1234 filesize limit, and large file support makes no difference there.
1235 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1236 NTFS has no practical limit on file size, and files of any size can be
1237 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001238
Tim Petersbdee63f2001-09-02 03:40:59 +00001239- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001240 points to command.com (patch from Brian Quinlan).
1241
Tim Petersedc99312001-08-22 21:36:50 +00001242
Tim Peters20f51a72001-07-21 02:31:40 +00001243What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001244Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001245===========================
1246
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001247Build
1248
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001249- Tim Peters developed a brand new Windows installer using Wise 8.1,
1250 generously donated to us by Wise Solutions.
1251
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001252- configure supports a new option --enable-unicode, with the values
1253 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1254 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001255
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001256- A new configure option --enable-framework builds a Mac OS X framework,
1257 which "make frameworkinstall" will install. This provides a starting
1258 point for more mac-like functionality, join pythonmac-sig@python.org
1259 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001260
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001261- The NeXT platform is no longer supported.
1262
1263- The `new' module is now statically linked.
1264
Tim Peters0afb6092001-08-15 06:06:44 +00001265Tools
1266
1267- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001268 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001269 the module docstring for details.
1270
Tim Peters20f51a72001-07-21 02:31:40 +00001271Tests
1272
Tim Peters5e824c32001-08-12 22:25:01 +00001273- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001274 platforms, allowing to give clearer test result output. regrtest
1275 also has optional --use/-u switch to run normally disabled tests
1276 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001277
Tim Peters20f51a72001-07-21 02:31:40 +00001278- Several new tests in the standard test suite, with special thanks to
1279 Nick Mathewson.
1280
1281Core
1282
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001283- The floor division operator // has been added as outlined in PEP
1284 238. The / operator still provides classic division (and will until
1285 Python 3.0) unless "from __future__ import division" is included, in
1286 which case the / operator will provide true division. The operator
1287 module provides truediv() and floordiv() functions. Augmented
1288 assignment variants are included, as are the equivalent overloadable
1289 methods and C API methods. See the PEP for a full discussion:
1290 <http://python.sf.net/peps/pep-0238.html>
1291
Tim Peters6cd6a822001-08-17 22:11:27 +00001292- Future statements are now effective in simulated interactive shells
1293 (like IDLE). This should "just work" by magic, but read Michael
1294 Hudson's "Future statements in simulated shells" PEP 264 for full
1295 details: <http://python.sf.net/peps/pep-0264.html>.
1296
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001297- The type/class unification (PEP 252-253) was integrated into the
1298 trunk and is not so tentative any more (the exact specification of
1299 some features is still tentative). A lot of work has done on fixing
1300 bugs and adding robustness and features (performance still has to
1301 come a long way).
1302
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001303- Warnings about a mismatch in the Python API during extension import
1304 now use the Python warning framework (which makes it possible to
1305 write filters for these warnings).
1306
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001307- A function's __dict__ (aka func_dict) will now always be a
1308 dictionary. It used to be possible to delete it or set it to None,
1309 but now both actions raise TypeErrors. It is still legal to set it
1310 to a dictionary object. Getting func.__dict__ before any attributes
1311 have been assigned now returns an empty dictionary instead of None.
1312
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001313- A new command line option, -E, was added which disables the use of
1314 all environment variables, or at least those that are specifically
1315 significant to Python. Usually those have a name starting with
1316 "PYTHON". This was used to fix a problem where the tests fail if
1317 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1318 older distribution.
1319
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001320Library
1321
Tim Peters5e824c32001-08-12 22:25:01 +00001322- New class Differ and new functions ndiff() and restore() in difflib.py.
1323 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001324 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001325
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001326- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1327 value using the minimal quoting required for the value; more
1328 reliable than using xml.sax.saxutils.escape() for attribute values.
1329
1330- Readline completion support for cmd.Cmd was added.
1331
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001332- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1333
1334- Added function threading.BoundedSemaphore()
1335
1336- Added Ka-Ping Yee's cgitb.py module.
1337
1338- The `new' module now exposes the CO_xxx flags.
1339
Martin v. Löwis560da622001-11-24 09:24:51 +00001340- The gc module offers the get_referents function.
1341
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001342New platforms
1343
1344C API
1345
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001346- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1347 which provide a cross-platform implementations for the
1348 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1349 the standard sprintf() and vsprintf() C lib APIs, these versions
1350 apply bounds checking on the used buffer which enhances protection
1351 against buffer overruns.
1352
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001353- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001354 and extensions using different Unicode widths is rendered next to
1355 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001356 will result in an ImportError. Unicode extensions writers must make
1357 sure to check the Unicode width compatibility in their extensions by
1358 using at least one of the mangled Unicode APIs in the extension.
1359
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001360- Two new flags METH_NOARGS and METH_O are available in method definition
1361 tables to simplify implementation of methods with no arguments and a
1362 single untyped argument. Calling such methods is more efficient than
1363 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1364 deprecated.
1365
Tim Petersc1731372001-08-04 08:12:36 +00001366Windows
1367
1368- "import module" now compiles module.pyw if it exists and nothing else
1369 relevant is found.
1370
Tim Peters20f51a72001-07-21 02:31:40 +00001371
Guido van Rossum55a78992001-07-17 17:22:32 +00001372What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001373Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001374===========================
1375
1376Core
Tim Petersa814db52001-05-14 07:05:58 +00001377
Tim Peters6d6c1a32001-08-02 04:15:00 +00001378- TENTATIVELY, a large amount of code implementing much of what's
1379 described in PEP 252 (Making Types Look More Like Classes) and PEP
1380 253 (Subtyping Built-in Types) was added. This will be released
1381 with Python 2.2a1. Documentation will be provided separately
1382 through http://www.python.org/2.2/. The purpose of releasing this
1383 with Python 2.2a1 is to test backwards compatibility. It is
1384 possible, though not likely, that a decision is made not to release
1385 this code as part of 2.2 final, if any serious backwards
1386 incompapatibilities are found during alpha testing that cannot be
1387 repaired.
1388
Guido van Rossum55a78992001-07-17 17:22:32 +00001389- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001390 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001391 more 'yield' statements. See PEP 255. Since this adds a new
1392 keyword to the language, this feature must be enabled by including a
1393 future statement: "from __future__ import generators" (see PEP 236).
1394 Generators will become a standard feature in a future release
1395 (probably 2.3). Without this future statement, 'yield' remains an
1396 ordinary identifier, but a warning is issued each time it is used.
1397 (These warnings currently don't conform to the warnings framework of
1398 PEP 230; we intend to fix this in 2.2a2.)
1399
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001400- The UTF-16 codec was modified to be more RFC compliant. It will now
1401 only remove BOM characters at the start of the string and then
1402 only if running in native mode (UTF-16-LE and -BE won't remove a
1403 leading BMO character).
1404
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001405- Strings now have a new method .decode() to complement the already
1406 existing .encode() method. These two methods provide direct access
1407 to the corresponding decoders and encoders of the registered codecs.
1408
1409 To enhance the usability of the .encode() method, the special
1410 casing of Unicode object return values was dropped (Unicode objects
1411 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001412
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001413 Both methods will now return whatever the codec in charge of the
1414 requested encoding returns as object, e.g. Unicode codecs will
1415 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1416 will return u"äöü"). This enables codec writer to create codecs
1417 for various simple to use conversions.
1418
1419 New codecs were added to demonstrate these new features (the .encode()
1420 and .decode() columns indicate the type of the returned objects):
1421
1422 Name | .encode() | .decode() | Description
1423 ----------------------------------------------------------------------
1424 uu | string | string | UU codec (e.g. for email)
1425 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001426 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001427 zlib | string | string | zlib compression
1428 hex | string | string | 2-byte hex codec
1429 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1430
Mark Hammond2a0af792001-05-14 03:09:36 +00001431- Some operating systems now support the concept of a default Unicode
1432 encoding for file system operations. Notably, Windows supports 'mbcs'
1433 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001434 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001435 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001436
1437 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001438 functions that return filenames (such as os.listdir()) to return Python
1439 string objects pre-encoded using the default file system encoding for
1440 the platform. As this encoding is likely to be different from Python's
1441 default encoding, converting this name to a Unicode object before passing
1442 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001443 would attempt to use its default encoding (generally ASCII) rather than
1444 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001445
Tim Petersa814db52001-05-14 07:05:58 +00001446 In general, this change simply removes surprises when working with
1447 Unicode and the file system, making these operations work as you expect,
1448 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001449 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001450
Tim Peters61dff2b2001-05-08 15:43:37 +00001451- Float (and complex) literals in source code were evaluated to full
1452 precision only when running from a .py file; the same code loaded from a
1453 .pyc (or .pyo) file could suffer numeric differences starting at about the
1454 12th significant decimal digit. For example, on a machine with IEEE-754
1455 floating arithmetic,
1456
1457 x = 9007199254740992.0
1458 print long(x)
1459
1460 printed 9007199254740992 if run directly from .py, but 9007199254740000
1461 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1462 str(float) instead of repr(float) when building code objects. marshal
1463 now uses repr(float) instead, which should reproduce floats to full
1464 machine precision (assuming the platform C float<->string I/O conversion
1465 functions are of good quality).
1466
1467 This may cause floating-point results to change in some cases, and
1468 usually for the better, but may also cause numerically unstable
1469 algorithms to break.
1470
Tim Peters2f228e72001-05-13 00:19:31 +00001471- The implementation of dicts suffers fewer collisions, which has speed
1472 benefits. However, the order in which dict entries appear in dict.keys(),
1473 dict.values() and dict.items() may differ from previous releases for a
1474 given dict. Nothing is defined about this order, so no program should
1475 rely on it. Nevertheless, it's easy to write test cases that rely on the
1476 order by accident, typically because of printing the str() or repr() of a
1477 dict to an "expected results" file. See Lib/test/test_support.py's new
1478 sortdict(dict) function for a simple way to display a dict in sorted
1479 order.
1480
Tim Peters7a3bfc32001-06-12 01:22:22 +00001481- Many other small changes to dicts were made, resulting in faster
1482 operation along the most common code paths.
1483
Guido van Rossum10315822001-05-01 20:54:30 +00001484- Dictionary objects now support the "in" operator: "x in dict" means
1485 the same as dict.has_key(x).
1486
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001487- The update() method of dictionaries now accepts generic mapping
1488 objects. Specifically the argument object must support the .keys()
1489 and __getitem__() methods. This allows you to say, for example,
1490 {}.update(UserDict())
1491
Guido van Rossum10315822001-05-01 20:54:30 +00001492- Iterators were added; this is a generalized way of providing values
1493 to a for loop. See PEP 234. There's a new built-in function iter()
1494 to return an iterator. There's a new protocol to get the next value
1495 from an iterator using the next() method (in Python) or the
1496 tp_iternext slot (in C). There's a new protocol to get iterators
1497 using the __iter__() method (in Python) or the tp_iter slot (in C).
1498 Iterating (i.e. a for loop) over a dictionary generates its keys.
1499 Iterating over a file generates its lines.
1500
Tim Petersf553f892001-05-01 20:45:31 +00001501- The following functions were generalized to work nicely with iterator
1502 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001503 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001504 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1505 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001506 join() method of strings
1507 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001508 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1509 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001510 right-hand side of assignment statements with multiple targets, such as
1511 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001512
Tim Petersd85e1022001-05-11 21:51:48 +00001513- Accessing module attributes is significantly faster (for example,
1514 random.random or os.path or yourPythonModule.yourAttribute).
1515
Tim Peterse63415e2001-05-08 04:38:29 +00001516- Comparing dictionary objects via == and != is faster, and now works even
1517 if the keys and values don't support comparisons other than ==.
1518
Tim Peters95bf9392001-05-10 08:32:44 +00001519- Comparing dictionaries in ways other than == and != is slower: there were
1520 insecurities in the dict comparison implementation that could cause Python
1521 to crash if the element comparison routines for the dict keys and/or
1522 values mutated the dicts. Making the code bulletproof slowed it down.
1523
Tim Peterseb28ef22001-06-02 05:27:19 +00001524- Collisions in dicts are resolved via a new approach, which can help
1525 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001526 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001527 faster now. Thanks to Christian Tismer for pointing out the cause and
1528 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001529
Tim Peters52e155e2001-06-16 05:42:57 +00001530- repr() is much faster for large containers (dict, list, tuple).
1531
1532
Tim Petersa814db52001-05-14 07:05:58 +00001533Library
1534
Fred Drake960fdf92001-07-20 18:38:26 +00001535- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1536 were added to the string module. These a locale-indenpendent
1537 constants, unlike letters, lowercase, and uppercase. These are now
1538 use in appropriate locations in the standard library.
1539
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001540- The flags used in dlopen calls can now be configured using
1541 sys.setdlopenflags and queried using sys.getdlopenflags.
1542
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001543- Fredrik Lundh's xmlrpclib is now a standard library module. This
1544 provides full client-side XML-RPC support. In addition,
1545 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1546 one asyncore-based). Thanks to Eric Raymond for the documentation.
1547
Guido van Rossum643d3912001-07-05 14:46:25 +00001548- The xrange() object is simplified: it no longer supports slicing,
1549 repetition, comparisons, efficient 'in' checking, the tolist()
1550 method, or the start, stop and step attributes. See PEP 260.
1551
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001552- A new function fnmatch.filter to filter lists of file names was added.
1553
Barry Warsawffd674d2001-05-22 16:00:10 +00001554- calendar.py uses month and day names based on the current locale.
1555
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001556- strop is now *really* obsolete (this was announced before with 1.6),
1557 and issues DeprecationWarning when used (except for the four items
1558 that are still imported into string.py).
1559
Tim Petersa814db52001-05-14 07:05:58 +00001560- Cookie.py now sorts key+value pairs by key in output strings.
1561
1562- pprint.isrecursive(object) didn't correctly identify recursive objects.
1563 Now it does.
1564
Tim Peters95b3f782001-05-14 18:39:41 +00001565- pprint functions now much faster for large containers (tuple, list, dict).
1566
Tim Peters7b9542a2001-06-10 23:40:19 +00001567- New 'q' and 'Q' format codes in the struct module, corresponding to C
1568 types "long long" and "unsigned long long" (on Windows, __int64). In
1569 native mode, these can be used only when the platform C compiler supports
1570 these types (when HAVE_LONG_LONG is #define'd by the Python config
1571 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001572 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1573 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001574
Guido van Rossum83213cc2001-06-12 16:48:52 +00001575- The site module installs a new built-in function 'help' that invokes
1576 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1577 it displays a message reminding the user to use 'help()' or
1578 'help(object)'.
1579
Tim Petersa814db52001-05-14 07:05:58 +00001580Tests
1581
1582- New test_mutants.py runs dict comparisons where the key and value
1583 comparison operators mutute the dicts randomly during comparison. This
1584 rapidly causes Python to crash under earlier releases (not for the faint
1585 of heart: it can also cause Win9x to freeze or reboot!).
1586
1587- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001588 pprint.isreadable() return sensible results. Also verifies that simple
1589 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001590
Tim Peters4324aa32001-05-28 22:30:08 +00001591C API
1592
1593- Removed the unused last_is_sticky argument from the internal
1594 _PyTuple_Resize(). If this affects you, you were cheating.
1595
1596
Guido van Rossum55a78992001-07-17 17:22:32 +00001597======================================================================
1598
1599
Guido van Rossumffe13be2001-04-16 18:46:45 +00001600What's New in Python 2.1 (final)?
1601=================================
1602
1603We only changed a few things since the last release candidate, all in
1604Python library code:
1605
1606- A bug in the locale module was fixed that affected locales which
1607 define no grouping for numeric formatting.
1608
1609- A few bugs in the weakref module's implementations of weak
1610 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1611 and the test suite was updated to check for these bugs.
1612
1613- An old bug in the os.path.walk() function (introduced in Python
1614 2.0!) was fixed: a non-existent file would cause an exception
1615 instead of being ignored.
1616
1617- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1618 PyChecker.
1619
1620
Guido van Rossum5b08f132001-04-16 02:05:23 +00001621What's New in Python 2.1c2?
1622===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001623
Guido van Rossum5b08f132001-04-16 02:05:23 +00001624A flurry of small changes, and one showstopper fixed in the nick of
1625time made it necessary to release another release candidate. The list
1626here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001627
Guido van Rossum5b08f132001-04-16 02:05:23 +00001628Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001629
Guido van Rossum5b08f132001-04-16 02:05:23 +00001630- Tim discovered a nasty bug in the dictionary code, caused by
1631 PyDict_Next() calling dict_resize(), and the GC code's use of
1632 PyDict_Next() violating an assumption in dict_items(). This was
1633 fixed with considerable amounts of band-aid, but the net effect is a
1634 saner and more robust implementation.
1635
1636- Made a bunch of symbols static that were accidentally global.
1637
1638Build and Ports
1639
1640- The setup.py script didn't check for a new enough version of zlib
1641 (1.1.3 is needed). Now it does.
1642
1643- Changed "make clean" target to also remove shared libraries.
1644
1645- Added a more general warning about the SGI Irix optimizer to README.
1646
1647Library
1648
1649- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1650 omitted the slash between host and file.html.
1651
1652- The mailbox module's _Mailbox class contained a completely broken
1653 and undocumented seek() method. Ripped it out.
1654
1655- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1656 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1657
1658- Fixed a few last-minute bugs in unittest.
1659
1660Extensions
1661
1662- Reverted the patch to the OpenSSL code in socketmodule.c to support
1663 RAND_status() and the EGD, and the subsequent patch that tried to
1664 fix it for pre-0.9.5 versions; the problem with the patch is that on
1665 some systems it issues a warning whenever socket is imported, and
1666 that's unacceptable.
1667
1668Tests
1669
1670- Fixed the pickle tests to work with "import test.test_pickle".
1671
1672- Tweaked test_locale.py to actually run the test Windows.
1673
1674- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1675 not "wb" (which is not a valid mode at all).
1676
1677- Fix pstats browser crashes. Import readline if it exists to make
1678 the user interface nicer.
1679
1680- Add "import thread" to the top of test modules that import the
1681 threading module (test_asynchat and test_threadedtempfile). This
1682 prevents test failures caused by a broken threading module resulting
1683 from a previously caught failed import.
1684
1685- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1686 needed on some platforms (e.g. Solaris 8) when the tests are run
1687 twice in succession.
1688
1689- Skip rather than fail test_sunaudiodev if no audio device is found.
1690
1691
1692What's New in Python 2.1c1?
1693===========================
1694
1695This list was significantly updated when 2.1c2 was released; the 2.1c1
1696release didn't mention most changes that were actually part of 2.1c1:
1697
1698Legal
1699
1700- Copyright was assigned to the Python Software Foundation (PSF) and a
1701 PSF license (very similar to the CNRI license) was added.
1702
1703- The CNRI copyright notice was updated to include 2001.
1704
1705Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001706
Guido van Rossumc9932722001-04-12 02:31:27 +00001707- After a public outcry, assignment to __debug__ is no longer illegal;
1708 instead, a warning is issued. It will become illegal in 2.2.
1709
Guido van Rossum5b08f132001-04-16 02:05:23 +00001710- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1711 "%#x" now always prepends "0x", even if the value is zero.
1712
1713- Fixed some nits in the bytecode compiler.
1714
1715- Fixed core dumps when calling certain kinds of non-functions.
1716
1717- Fixed various core dumps caused by reference count bugs.
1718
1719Build and Ports
1720
1721- Use INSTALL_SCRIPT to install script files.
1722
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001723- New port: SCO Unixware 7, by Billy G. Allie.
1724
Guido van Rossum5b08f132001-04-16 02:05:23 +00001725- Updated RISCOS port.
1726
1727- Updated BeOS port and notes.
1728
1729- Various other porting problems resolved.
1730
1731Library
1732
1733- The TERMIOS and SOCKET modules are now truly obsolete and
1734 unnecessary. Their symbols are incorporated in the termios and
1735 socket modules.
1736
1737- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1738 better tests for pickling.
1739
1740- threading: make Condition.wait() robust against KeyboardInterrupt.
1741
1742- zipfile: add support to zipfile to support opening an archive
1743 represented by an open file rather than a file name. Fix bug where
1744 the archive was not properly closed. Fixed a bug in this bugfix
1745 where flush() was called for a read-only file.
1746
1747- imputil: added an uninstall() method to the ImportManager.
1748
1749- Canvas: fixed bugs in lower() and tkraise() methods.
1750
1751- SocketServer: API change (added overridable close_request() method)
1752 so that the TCP server can explicitly close the request.
1753
1754- pstats: Eric Raymond added a simple interactive statistics browser,
1755 invoked when the module is run as a script.
1756
1757- locale: fixed a problem in format().
1758
1759- webbrowser: made it work when the BROWSER environment variable has a
1760 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1761 KDE 2. Fixed some other nits.
1762
1763- unittest: changes to allow using a different exception than
1764 AssertionError, and added a few more function aliases. Some other
1765 small changes.
1766
1767- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1768
1769- asynchat: fixed a critical bug in asynchat that slipped through the
1770 2.1b2 release. Fixed another rare bug.
1771
1772- Fix some unqualified except: clauses (always a bad code example).
1773
1774XML
1775
1776- pyexpat: new API get_version_string().
1777
1778- Fixed some minidom bugs.
1779
1780Extensions
1781
1782- Fixed a core dump in _weakref. Removed the weakref.mapping()
1783 function (it adds nothing to the API).
1784
1785- Rationalized the use of header files in the readline module, to make
1786 it compile (albeit with some warnings) with the very recent readline
1787 4.2, without breaking for earlier versions.
1788
1789- Hopefully fixed a buffering problem in linuxaudiodev.
1790
1791- Attempted a fix to make the OpenSSL support in the socket module
1792 work again with pre-0.9.5 versions of OpenSSL.
1793
1794Tests
1795
1796- Added a test case for asynchat and asyncore.
1797
1798- Removed coupling between tests where one test failing could break
1799 another.
1800
1801Tools
1802
1803- Ping added an interactive help browser to pydoc, fixed some nits
1804 in the rest of the pydoc code, and added some features to his
1805 inspect module.
1806
1807- An updated python-mode.el version 4.1 which integrates Ken
1808 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1809 much nicer in XEmacs and Emacs. When stepping through your program
1810 with pdb, in either the shell window or the *Python* window, the
1811 source file and line will be tracked by an arrow. Very cool!
1812
1813- IDLE: syntax warnings in interactive mode are changed into errors.
1814
1815- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001816 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001817
1818- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001819
Barry Warsaw11e89c72001-04-11 20:37:57 +00001820
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001821What's New in Python 2.1 beta 2?
1822================================
1823
Guido van Rossum053ae352001-03-22 14:17:21 +00001824(Unlisted are many fixed bugs, more documentation, etc.)
1825
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001826Core language, builtins, and interpreter
1827
Guido van Rossum053ae352001-03-22 14:17:21 +00001828- The nested scopes work (enabled by "from __future__ import
1829 nested_scopes") is completed; in particular, the future now extends
1830 into code executed through exec, eval() and execfile(), and into the
1831 interactive interpreter.
1832
1833- When calling a base class method (e.g. BaseClass.__init__(self)),
1834 this is now allowed even if self is not strictly spoken a class
1835 instance (e.g. when using metaclasses or the Don Beaudry hook).
1836
1837- Slice objects are now comparable but not hashable; this prevents
1838 dict[:] from being accepted but meaningless.
1839
1840- Complex division is now calculated using less braindead algorithms.
1841 This doesn't change semantics except it's more likely to give useful
1842 results in extreme cases. Complex repr() now uses full precision
1843 like float repr().
1844
1845- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1846
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001847- It is illegal to assign to the name __debug__, which is set when the
1848 interpreter starts. It is effectively a compile-time constant.
1849
1850- A warning will be issued if a global statement for a variable
1851 follows a use or assignment of that variable.
1852
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001853Standard library
1854
Guido van Rossum053ae352001-03-22 14:17:21 +00001855- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1856 inspired by JUnit), is now part of the standard library. You now
1857 have a choice of two testing frameworks: unittest requires you to
1858 write testcases as separate code, doctest gathers them from
1859 docstrings. Both approaches have their advantages and
1860 disadvantages.
1861
1862- A new module Tix was added, which wraps the Tix extension library
1863 for Tk. With that module, it is not necessary to statically link
1864 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1865 require" command. See Demo/tix/.
1866
1867- tzparse.py is now obsolete.
1868
1869- In gzip.py, the seek() and tell() methods are removed -- they were
1870 non-functional anyway, and it's better if callers can test for their
1871 existence with hasattr().
1872
1873Python/C API
1874
1875- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1876 that's already in the dictionary during a PyDict_Next() iteration.
1877 This used to fail occasionally when a dictionary resize operation
1878 could be triggered that would rehash all the keys. All other
1879 modifications to the dictionary are still off-limits during a
1880 PyDict_Next() iteration!
1881
1882- New extended APIs related to passing compiler variables around.
1883
1884- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1885 implement isinstance() and issubclass().
1886
1887- Py_BuildValue() now has a "D" conversion to create a Python complex
1888 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001889
Fred Drake4e262a92001-03-22 18:26:47 +00001890- Extensions types which support weak references must now set the
1891 field allocated for the weak reference machinery to NULL themselves;
1892 this is done to avoid the cost of checking each object for having a
1893 weakly referencable type in PyObject_INIT(), since most types are
1894 not weakly referencable.
1895
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001896- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1897 free variables and cell variables to and from the frame's f_locals.
1898
1899- Variants of several functions defined in pythonrun.h have been added
1900 to support the nested_scopes future statement. The variants all end
1901 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1902 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1903 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001904 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001905
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001906Distutils
1907
1908- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1909 into the release tree.
1910
Tim Peters0e57abf2001-05-02 07:39:38 +00001911- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001912 (an uninstaller, more customization of the installer's display)
1913
1914- from Jack Jansen: added Mac-specific code to generate a dialog for
1915 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001916 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001917 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001918
1919- added 'platforms' and 'keywords' to the set of metadata that can be
1920 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001921
1922- applied patches from Jason Tishler to make the compiler class work with
1923 Cygwin.
1924
1925
Tim Peters2fe289a2001-03-01 22:19:38 +00001926What's New in Python 2.1 beta 1?
1927================================
Tim Petersd66595f2001-02-04 03:09:53 +00001928
1929Core language, builtins, and interpreter
1930
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001931- Following an outcry from the community about the amount of code
1932 broken by the nested scopes feature introduced in 2.1a2, we decided
1933 to make this feature optional, and to wait until Python 2.2 (or at
1934 least 6 months) to make it standard. The option can be enabled on a
1935 per-module basis by adding "from __future__ import nested_scopes" at
1936 the beginning of a module (before any other statements, but after
1937 comments and an optional docstring). See PEP 236 (Back to the
1938 __future__) for a description of the __future__ statement. PEP 227
1939 (Statically Nested Scopes) has been updated to reflect this change,
1940 and to clarify the semantics in a number of endcases.
1941
1942- The nested scopes code, when enabled, has been hardened, and most
1943 bugs and memory leaks in it have been fixed.
1944
1945- Compile-time warnings are now generated for a number of conditions
1946 that will break or change in meaning when nested scopes are enabled:
1947
1948 - Using "from...import *" or "exec" without in-clause in a function
1949 scope that also defines a lambda or nested function with one or
1950 more free (non-local) variables. The presence of the import* or
1951 bare exec makes it impossible for the compiler to determine the
1952 exact set of local variables in the outer scope, which makes it
1953 impossible to determine the bindings for free variables in the
1954 inner scope. To avoid the warning about import *, change it into
1955 an import of explicitly name object, or move the import* statement
1956 to the global scope; to avoid the warning about bare exec, use
1957 exec...in... (a good idea anyway -- there's a possibility that
1958 bare exec will be deprecated in the future).
1959
1960 - Use of a global variable in a nested scope with the same name as a
1961 local variable in a surrounding scope. This will change in
1962 meaning with nested scopes: the name in the inner scope will
1963 reference the variable in the outer scope rather than the global
1964 of the same name. To avoid the warning, either rename the outer
1965 variable, or use a global statement in the inner function.
1966
Neil Schemenauera35c6882001-02-27 04:45:05 +00001967- An optional object allocator has been included. This allocator is
1968 optimized for Python objects and should be faster and use less memory
1969 than the standard system allocator. It is not enabled by default
1970 because of possible thread safety problems. The allocator is only
1971 protected by the Python interpreter lock and it is possible that some
1972 extension modules require a thread safe allocator. The object
1973 allocator can be enabled by providing the "--with-pymalloc" option to
1974 configure.
1975
Tim Petersd66595f2001-02-04 03:09:53 +00001976Standard library
1977
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001978- pyexpat now detects the expat version if expat.h defines it. A
1979 number of additional handlers are provided, which are only available
1980 since expat 1.95. In addition, the methods SetParamEntityParsing and
1981 GetInputContext of Parser objects are available with 1.95.x
1982 only. Parser objects now provide the ordered_attributes and
1983 specified_attributes attributes. A new module expat.model was added,
1984 which offers a number of additional constants if 1.95.x is used.
1985
1986- xml.dom offers the new functions registerDOMImplementation and
1987 getDOMImplementation.
1988
1989- xml.dom.minidom offers a toprettyxml method. A number of DOM
1990 conformance issues have been resolved. In particular, Element now
1991 has an hasAttributes method, and the handling of namespaces was
1992 improved.
1993
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001994- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1995 getting information about live Python code, and pydoc.py, a module
1996 for interactively converting docstrings to HTML or text.
1997 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001998 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001999 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2000 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002001
Tim Peters1eff7962001-03-01 02:31:33 +00002002- New library module difflib.py, primarily packaging the SequenceMatcher
2003 class at the heart of the popular ndiff.py file-comparison tool.
2004
2005- doctest.py (a framework for verifying Python code examples in docstrings)
2006 is now part of the std library.
2007
Tim Petersd66595f2001-02-04 03:09:53 +00002008Windows changes
2009
Guido van Rossume3955a82001-03-02 14:05:59 +00002010- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2011 small GUI that lets you browse the module docstrings using your
2012 default web browser.
2013
Tim Peters1eff7962001-03-01 02:31:33 +00002014- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2015 Platforms) is implemented. See
2016
2017 http://python.sourceforge.net/peps/pep-0235.html
2018
2019 for full details, especially the "Current Lower-Left Semantics" section.
2020 The new Windows import rules are simpler than before:
2021
2022 A. If the PYTHONCASEOK environment variable exists, same as
2023 before: silently accept the first case-insensitive match of any
2024 kind; raise ImportError if none found.
2025
2026 B. Else search sys.path for the first case-sensitive match; raise
2027 ImportError if none found.
2028
2029 The same rules have been implented on other platforms with case-
2030 insensitive but case-preserving filesystems too (including Cygwin, and
2031 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002032
Tim Peters25a9ce32001-02-19 07:06:36 +00002033- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2034 what it's supposed to do (and does do under NT and 2000) via direct
2035 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002036 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002037 all Win9x systems before.
2038
Tim Peters1eff7962001-03-01 02:31:33 +00002039- Build: Subproject _test (effectively) renamed to _testcapi.
2040
Tim Peters2fe289a2001-03-01 22:19:38 +00002041New platforms
2042
2043- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2044 Thanks to Steven Majewski!
2045
2046- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2047 Tishler!
2048
Guido van Rossum9089b272001-03-02 06:49:50 +00002049- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2050 Schwertberger! See RISCOS/README for more information -- it seems
2051 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002052 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002053
Tim Peters25a9ce32001-02-19 07:06:36 +00002054
Tim Petersd7b5e882001-01-25 03:36:26 +00002055What's New in Python 2.1 alpha 2?
2056=================================
Tim Peters40ead762001-01-27 05:35:26 +00002057
Tim Petersd7b5e882001-01-25 03:36:26 +00002058Core language, builtins, and interpreter
2059
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002060- Scopes nest. If a name is used in a function or class, but is not
2061 local, the definition in the nearest enclosing function scope will
2062 be used. One consequence of this change is that lambda statements
2063 could reference variables in the namespaces where the lambda is
2064 defined. In some unusual cases, this change will break code.
2065
2066 In all previous version of Python, names were resolved in exactly
2067 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002068 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002069 function A is defined within a function B, the names bound in B are
2070 not visible in A. The new rules make names bound in B visible in A,
2071 unless A contains a name binding that hides the binding in B.
2072
2073 Section 4.1 of the reference manual describes the new scoping rules
2074 in detail. The test script in Lib/test/test_scope.py demonstrates
2075 some of the effects of the change.
2076
2077 The new rules will cause existing code to break if it defines nested
2078 functions where an outer function has local variables with the same
2079 name as globals or builtins used by the inner function. Example:
2080
2081 def munge(str):
2082 def helper(x):
2083 return str(x)
2084 if type(str) != type(''):
2085 str = helper(str)
2086 return str.strip()
2087
2088 Under the old rules, the name str in helper() is bound to the
2089 builtin function str(). Under the new rules, it will be bound to
2090 the argument named str and an error will occur when helper() is
2091 called.
2092
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002093- The compiler will report a SyntaxError if "from ... import *" occurs
2094 in a function or class scope. The language reference has documented
2095 that this case is illegal, but the compiler never checked for it.
2096 The recent introduction of nested scope makes the meaning of this
2097 form of name binding ambiguous. In a future release, the compiler
2098 may allow this form when there is no possibility of ambiguity.
2099
Tim Peters40ead762001-01-27 05:35:26 +00002100- repr(string) is easier to read, now using hex escapes instead of octal,
2101 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2102
2103 >>> "\texample \r\n" + chr(0) + chr(255)
2104 '\texample \r\n\x00\xff' # in 2.1
2105 '\011example \015\012\000\377' # in 2.0
2106
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002107- Functions are now compared and hashed by identity, not by value, since
2108 the func_code attribute is writable.
2109
Fred Drakefb9d7122001-02-01 20:00:40 +00002110- Weak references (PEP 205) have been added. This involves a few
2111 changes in the core, an extension module (_weakref), and a Python
2112 module (weakref). The weakref module is the public interface. It
2113 includes support for "explicit" weak references, proxy objects, and
2114 mappings with weakly held values.
2115
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002116- A 'continue' statement can now appear in a try block within the body
2117 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002118 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002119
Tim Petersd7b5e882001-01-25 03:36:26 +00002120Standard library
2121
Barry Warsaw30dbd142001-01-31 22:14:01 +00002122- mailbox.py now has a new class, PortableUnixMailbox which is
2123 identical to UnixMailbox but uses a more portable scheme for
2124 determining From_ separators. Also, the constructors for all the
2125 classes in this module have a new optional `factory' argument, which
2126 is a callable used when new message classes must be instantiated by
2127 the next() method.
2128
Tim Petersd7b5e882001-01-25 03:36:26 +00002129- random.py is now self-contained, and offers all the functionality of
2130 the now-deprecated whrandom.py. See the docs for details. random.py
2131 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002132 and restoring the internal state of the generator; and jumpahead(n),
2133 for quickly forcing the internal state to be the same as if n calls to
2134 random() had been made. The latter is particularly useful for multi-
2135 threaded programs, creating one instance of the random.Random() class for
2136 each thread, then using .jumpahead() to force each instance to use a
2137 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002138
Tim Peters0de88fc2001-02-01 04:59:18 +00002139- random.py's seed() function is new. For bit-for-bit compatibility with
2140 prior releases, use the whseed function instead. The new seed function
2141 addresses two problems: (1) The old function couldn't produce more than
2142 about 2**24 distinct internal states; the new one about 2**45 (the best
2143 that can be done in the Wichmann-Hill generator). (2) The old function
2144 sometimes produced identical internal states when passed distinct
2145 integers, and there was no simple way to predict when that would happen;
2146 the new one guarantees to produce distinct internal states for all
2147 arguments in [0, 27814431486576L).
2148
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002149- The socket module now supports raw packets on Linux. The socket
2150 family is AF_PACKET.
2151
Tim Peters9ea17ac2001-02-02 05:57:15 +00002152- test_capi.py is a start at running tests of the Python C API. The tests
2153 are implemented by the new Modules/_testmodule.c.
2154
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002155- A new extension module, _symtable, provides provisional access to the
2156 internal symbol table used by the Python compiler. A higher-level
2157 interface will be added on top of _symtable in a future release.
2158
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002159- Removed the obsolete soundex module.
2160
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002161- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2162 the isSameNode method; NamedNodeMap the get method.
2163
2164- xml.sax.expatreader supports the lexical handler property; it
2165 generates comment, startCDATA, and endCDATA events.
2166
Tim Petersee826f82001-01-31 19:39:44 +00002167Windows changes
2168
2169- Build procedure: the zlib project is built in a different way that
2170 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002171 the zlib binary used. See PCbuild\readme.txt for details. Your old
2172 zlib-related directories can be deleted; you'll need to download fresh
2173 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002174
Tim Peters9ea17ac2001-02-02 05:57:15 +00002175- Build: New subproject _test for the benefit of test_capi.py (see above).
2176
Tim Petersb16c56f2001-02-02 21:24:51 +00002177- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2178 interface to some Python compiler internals).
2179
2180- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002181 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002182
Tim Petersa3a3a032000-11-30 05:22:44 +00002183What's New in Python 2.1 alpha 1?
2184=================================
2185
2186Core language, builtins, and interpreter
2187
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002188- There is a new Unicode companion to the PyObject_Str() API
2189 called PyObject_Unicode(). It behaves in the same way as the
2190 former, but assures that the returned value is an Unicode object
2191 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002192
Guido van Rossumf98eda02001-01-17 15:54:45 +00002193- The comparison operators support "rich comparison overloading" (PEP
2194 207). C extension types can provide a rich comparison function in
2195 the new tp_richcompare slot in the type object. The cmp() function
2196 and the C function PyObject_Compare() first try the new rich
2197 comparison operators before trying the old 3-way comparison. There
2198 is also a new C API PyObject_RichCompare() (which also falls back on
2199 the old 3-way comparison, but does not constrain the outcome of the
2200 rich comparison to a Boolean result).
2201
2202 The rich comparison function takes two objects (at least one of
2203 which is guaranteed to have the type that provided the function) and
2204 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2205 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2206 object, which may be NotImplemented (in which case the tp_compare
2207 slot function is used as a fallback, if defined).
2208
2209 Classes can overload individual comparison operators by defining one
2210 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002211 __ge__. There are no explicit "reflected argument" versions of
2212 these; instead, __lt__ and __gt__ are each other's reflection,
2213 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2214 reflection (similar at the C level). No other implications are
2215 made; in particular, Python does not assume that == is the Boolean
2216 inverse of !=, or that < is the Boolean inverse of >=. This makes
2217 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002218
2219 Classes or types that want to implement (in)equality tests but not
2220 the ordering operators (i.e. unordered types) should implement ==
2221 and !=, and raise an error for the ordering operators.
2222
Guido van Rossuma88479f2001-01-18 14:28:08 +00002223 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002224 Boolean; e.g. a matrix type might want to return a matrix of bits
2225 for A < B, giving elementwise comparisons. Such types should ensure
2226 that any interpretation of their value in a Boolean context raises
2227 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2228 at the C level) to always raise an exception.
2229
Guido van Rossuma88479f2001-01-18 14:28:08 +00002230- Complex numbers use rich comparisons to define == and != but raise
2231 an exception for <, <=, > and >=. Unfortunately, this also means
2232 that cmp() of two complex numbers raises an exception when the two
2233 numbers differ. Since it is not mathematically meaningful to compare
2234 complex numbers except for equality, I hope that this doesn't break
2235 too much code.
2236
Tim Peters3389f192001-02-18 08:48:49 +00002237- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002238 not defined by the language, other than that it's arbitrary but
2239 consistent (see the Reference Manual). An implementation detail changed
2240 in 2.1a1 such that None now compares less than any other object. Code
2241 relying on this new behavior (like code that relied on the previous
2242 behavior) does so at its own risk.
2243
Barry Warsaw573b5412001-01-15 20:43:18 +00002244- Functions and methods now support getting and setting arbitrarily
2245 named attributes (PEP 232). Functions have a new __dict__
2246 (a.k.a. func_dict) which hold the function attributes. Methods get
2247 and set attributes on their underlying im_func. It is a TypeError
2248 to set an attribute on a bound method.
2249
Guido van Rossum051e3352001-01-15 19:11:10 +00002250- The xrange() object implementation has been improved so that
2251 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2252 limitation that in this case len(xrange(sys.maxint)) can't be
2253 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2254 work fine as long as the index i doesn't actually reach 2**31.
2255 (Python uses regular ints for sequence and string indices; fixing
2256 that is much more work.)
2257
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002258- Two changes to from...import:
2259
Guido van Rossumba381232001-02-03 15:06:40 +00002260 1) "from M import X" now works even if (after loading module M)
2261 sys.modules['M'] is not a real module; it's basically a getattr()
2262 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002263
2264 2) "from M import *" now looks for M.__all__ to decide which names to
2265 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2266 filters out names starting with '_' as before. Whether or not
2267 __all__ exists, there's no restriction on the type of M.
2268
Guido van Rossumf61f1662001-01-10 20:13:55 +00002269- File objects have a new method, xreadlines(). This is the fastest
2270 way to iterate over all lines in a file:
2271
2272 for line in file.xreadlines():
2273 ...do something to line...
2274
2275 See the xreadlines module (mentioned below) for how to do this for
2276 other file-like objects.
2277
2278- Even if you don't use file.xreadlines(), you may expect a speedup on
2279 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002280 quite a bit in platform-specific ways: on systems (like Linux) that
2281 support flockfile(), getc_unlocked(), and funlockfile(), those are
2282 used by default. On systems (like Windows) without getc_unlocked(),
2283 a complicated (but still thread-safe) method using fgets() is used by
2284 default.
2285
Tim Petersd52269b2001-01-25 06:23:18 +00002286 You can force use of the fgets() method by #define'ing
2287 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002288 getc_unlocked()).
2289
Tim Petersd52269b2001-01-25 06:23:18 +00002290 You can force fgets() not to be used by #define'ing
2291 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002292 test_bufio.py fails -- and let us know if it does!).
2293
2294- In addition, the fileinput module, while still slower than the other
2295 methods on most platforms, has been sped up too, by using
2296 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002297
2298- Support for run-time warnings has been added, including a new
2299 command line option (-W) to specify the disposition of warnings.
2300 See the description of the warnings module below.
2301
2302- Extensive changes have been made to the coercion code. This mostly
2303 affects extension modules (which can now implement mixed-type
2304 numerical operators without having to use coercion), but
2305 occasionally, in boundary cases the coercion semantics have changed
2306 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002307 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002308 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002309 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002310
Guido van Rossumf98eda02001-01-17 15:54:45 +00002311- In connection with the coercion changes, a new built-in singleton
2312 object, NotImplemented is defined. This can be returned for
2313 operations that wish to indicate they are not implemented for a
2314 particular combination of arguments. From C, this is
2315 Py_NotImplemented.
2316
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002317- The interpreter accepts now bytecode files on the command line even
2318 if they do not have a .pyc or .pyo extension. On Linux, after executing
2319
Martin v. Löwise214baa2001-02-04 22:37:56 +00002320import imp,sys,string
2321magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2322reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2323open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002324
2325 any byte code file can be used as an executable (i.e. as an argument
2326 to execve(2)).
2327
Tim Peters9940b802000-12-01 07:59:35 +00002328- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002329 character. In 1.6 and earlier, they never produced a sign,
2330 and raised an error if the value of the long was too large
2331 to fit in a Python int. In 2.0, they produced a sign if and
2332 only if too large to fit in an int. This was inconsistent
2333 across platforms (because the size of an int varies across
2334 platforms), and inconsistent with hex() and oct(). Example:
2335
2336 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002337 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002338 'ffffffbe' # in 2.0 and before, on 32-bit machines
2339 >>> hex(-0x42L)
2340 '-0x42L' # in all versions of Python
2341
Tim Peters9940b802000-12-01 07:59:35 +00002342 The behavior of %d formats for negative Python longs remains
2343 the same as in 2.0 (although in 1.6 and before, they raised
2344 an error if the long didn't fit in a Python int).
2345
2346 %u formats don't make sense for Python longs, but are allowed
2347 and treated the same as %d in 2.1. In 2.0, a negative long
2348 formatted via %u produced a sign if and only if too large to
2349 fit in an int. In 1.6 and earlier, a negative long formatted
2350 via %u raised an error if it was too big to fit in an int.
2351
Guido van Rossum3661d392000-12-12 22:10:31 +00002352- Dictionary objects have an odd new method, popitem(). This removes
2353 an arbitrary item from the dictionary and returns it (in the form of
2354 a (key, value) pair). This can be useful for algorithms that use a
2355 dictionary as a bag of "to do" items and repeatedly need to pick one
2356 item. Such algorithms normally end up running in quadratic time;
2357 using popitem() they can usually be made to run in linear time.
2358
Tim Peters36cdad12000-12-29 02:06:45 +00002359Standard library
2360
Thomas Woutersfe385252001-01-19 23:16:56 +00002361- In the time module, the time argument to the functions strftime,
2362 localtime, gmtime, asctime and ctime is now optional, defaulting to
2363 the current time (in the local timezone).
2364
Guido van Rossumda91f222001-01-15 16:36:08 +00002365- The ftplib module now defaults to passive mode, which is deemed a
2366 more useful default given that clients are often inside firewalls
2367 these days. Note that this could break if ftplib is used to connect
2368 to a *server* that is inside a firewall, from outside; this is
2369 expected to be a very rare situation. To fix that, you can call
2370 ftp.set_pasv(0).
2371
Martin v. Löwis10a27872001-01-13 09:54:41 +00002372- The module site now treats .pth files not only for path configuration,
2373 but also supports extensions to the initialization code: Lines starting
2374 with import are executed.
2375
Guido van Rossumf61f1662001-01-10 20:13:55 +00002376- There's a new module, warnings, which implements a mechanism for
2377 issuing and filtering warnings. There are some new built-in
2378 exceptions that serve as warning categories, and a new command line
2379 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2380 turns warnings into errors). warnings.warn(message[, category])
2381 issues a warning message; this can also be called from C as
2382 PyErr_Warn(category, message).
2383
2384- A new module xreadlines was added. This exports a single factory
2385 function, xreadlines(). The intention is that this code is the
2386 absolutely fastest way to iterate over all lines in an open
2387 file(-like) object:
2388
2389 import xreadlines
2390 for line in xreadlines.xreadlines(file):
2391 ...do something to line...
2392
2393 This is equivalent to the previous the speed record holder using
2394 file.readlines(sizehint). Note that if file is a real file object
2395 (as opposed to a file-like object), this is equivalent:
2396
2397 for line in file.xreadlines():
2398 ...do something to line...
2399
Tim Peters36cdad12000-12-29 02:06:45 +00002400- The bisect module has new functions bisect_left, insort_left,
2401 bisect_right and insort_right. The old names bisect and insort
2402 are now aliases for bisect_right and insort_right. XXX_right
2403 and XXX_left methods differ in what happens when the new element
2404 compares equal to one or more elements already in the list: the
2405 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002406 right. Code that doesn't care where equal elements end up should
2407 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002408
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002409- The new curses.panel module wraps the panel library that forms part
2410 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2411
Guido van Rossumf61f1662001-01-10 20:13:55 +00002412- The SocketServer module now sets the allow_reuse_address flag by
2413 default in the TCPServer class.
2414
2415- A new function, sys._getframe(), returns the stack frame pointer of
2416 the caller. This is intended only as a building block for
2417 higher-level mechanisms such as string interpolation.
2418
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002419- The pyexpat module supports a number of new handlers, which are
2420 available only in expat 1.2. If invocation of a callback fails, it
2421 will report an additional frame in the traceback. Parser objects
2422 participate now in garbage collection. If expat reports an unknown
2423 encoding, pyexpat will try to use a Python codec; that works only
2424 for single-byte charsets. The parser type objects is exposed as
2425 XMLParserObject.
2426
2427- xml.dom now offers standard definitions for symbolic node type and
2428 exception code constants, and a hierarchy of DOM exceptions. minidom
2429 was adjusted to use them.
2430
2431- The conformance of xml.dom.minidom to the DOM specification was
2432 improved. It detects a number of additional error cases; the
2433 previous/next relationship works even when the tree is modified;
2434 Node supports the normalize() method; NamedNodeMap, DocumentType and
2435 DOMImplementation classes were added; Element supports the
2436 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2437 method.
2438
Guido van Rossumf61f1662001-01-10 20:13:55 +00002439Build issues
2440
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002441- For Unix (and Unix-compatible) builds, configuration and building of
2442 extension modules is now greatly automated. Rather than having to
2443 edit the Modules/Setup file to indicate which modules should be
2444 built and where their include files and libraries are, a
2445 distutils-based setup.py script now takes care of building most
2446 extension modules. All extension modules built this way are built
2447 as shared libraries. Only a few modules that must be linked
2448 statically are still listed in the Setup file; you won't need to
2449 edit their configuration.
2450
2451- Python should now build out of the box on Cygwin. If it doesn't,
2452 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002453
2454- Python now always uses its own (renamed) implementation of getopt()
2455 -- there's too much variation among C library getopt()
2456 implementations.
2457
2458- C++ compilers are better supported; the CXX macro is always set to a
2459 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002460
Tim Petersd92dfe02000-12-12 01:18:41 +00002461Windows changes
2462
2463- select module: By default under Windows, a select() call
2464 can specify no more than 64 sockets. Python now boosts
2465 this Microsoft default to 512. If you need even more than
2466 that, see the MS docs (you'll need to #define FD_SETSIZE
2467 and recompile Python from source).
2468
Guido van Rossumf61f1662001-01-10 20:13:55 +00002469- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2470 subdirectory is no more!
2471
Tim Petersa3a3a032000-11-30 05:22:44 +00002472
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002473What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002474=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002475
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002476Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002477changes are in the file HISTORY. If you are making the jump directly
2478from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2479HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002480
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002481Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2482the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2483http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002484
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002485--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002486
2487======================================================================
2488
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002489What's new in 2.0 (since release candidate 1)?
2490==============================================
2491
2492Standard library
2493
2494- The copy_reg module was modified to clarify its intended use: to
2495 register pickle support for extension types, not for classes.
2496 pickle() will raise a TypeError if it is passed a class.
2497
2498- Fixed a bug in gettext's "normalize and expand" code that prevented
2499 it from finding an existing .mo file.
2500
2501- Restored support for HTTP/0.9 servers in httplib.
2502
Tim Peters989b7b92000-10-16 20:24:53 +00002503- The math module was changed to stop raising OverflowError in case of
2504 underflow, and return 0 instead in underflow cases. Whether Python
2505 used to raise OverflowError in case of underflow was platform-
2506 dependent (it did when the platform math library set errno to ERANGE
2507 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002508
2509- Fixed a bug in StringIO that occurred when the file position was not
2510 at the end of the file and write() was called with enough data to
2511 extend past the end of the file.
2512
2513- Fixed a bug that caused Tkinter error messages to get lost on
2514 Windows. The bug was fixed by replacing direct use of
2515 interp->result with Tcl_GetStringResult(interp).
2516
2517- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2518 redirect response.
2519
2520- Several changes were made to distutils: Some debugging code was
2521 removed from util. Fixed the installer used when an external zip
2522 program (like WinZip) is not found; the source code for this
2523 installer is in Misc/distutils. check_lib() was modified to behave
2524 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2525 test for whether installed modules are on sys.path was changed to
2526 use both normcase() and normpath().
2527
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002528- Several minor bugs were fixed in the xml package (the minidom,
2529 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002530
2531- The regression test driver (regrtest.py) behavior when invoked with
2532 -l changed: It now reports a count of objects that are recognized as
2533 garbage but not freed by the garbage collector.
2534
Tim Peters989b7b92000-10-16 20:24:53 +00002535- The regression test for the math module was changed to test
2536 exceptional behavior when the test is run in verbose mode. Python
2537 cannot yet guarantee consistent exception behavior across platforms,
2538 so the exception part of test_math is run only in verbose mode, and
2539 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002540
2541Internals
2542
2543- PyOS_CheckStack() has been disabled on Win64, where it caused
2544 test_sre to fail.
2545
2546Build issues
2547
2548- Changed compiler flags, so that gcc is always invoked with -Wall and
2549 -Wstrict-prototypes. Users compiling Python with GCC should see
2550 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002551 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002552 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002553
Tim Petersa3a3a032000-11-30 05:22:44 +00002554- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002555
2556Tools and other miscellany
2557
2558- The compiler in Tools/compiler was updated to support the new
2559 language features introduced in 2.0: extended print statement, list
2560 comprehensions, and augmented assignments. The new compiler should
2561 also be backwards compatible with Python 1.5.2; the compiler will
2562 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002563 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002564
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002565What's new in 2.0 release candidate 1 (since beta 2)?
2566=====================================================
2567
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002568What is release candidate 1?
2569
2570We believe that release candidate 1 will fix all known bugs that we
2571intend to fix for the 2.0 final release. This release should be a bit
2572more stable than the previous betas. We would like to see even more
2573widespread testing before the final release, so we are producing this
2574release candidate. The final release will be exactly the same unless
2575any show-stopping (or brown bag) bugs are found by testers of the
2576release candidate.
2577
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002578All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002579to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002580
2581Core language, builtins, and interpreter
2582
2583- A bug that caused crashes when __coerce__ was used with augmented
2584 assignment, e.g. +=, was fixed.
2585
2586- Raise ZeroDivisionError when raising zero to a negative number,
2587 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2588 power operator and the result of math.pow(0.0, -2.0) will vary by
2589 platform. On Linux, it raises a ValueError.
2590
2591- A bug in Unicode string interpolation was fixed that occasionally
2592 caused errors with formats including "%%". For example, the
2593 following expression "%% %s" % u"abc" no longer raises a TypeError.
2594
2595- Compilation of deeply nested expressions raises MemoryError instead
2596 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2597
2598- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2599 rendering them useless. They are now written in binary mode again.
2600
2601Standard library
2602
2603- Keyword arguments are now accepted for most pattern and match object
2604 methods in SRE, the standard regular expression engine.
2605
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002606- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002607 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002608
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002609- Several bugs in the Unicode handling and error handling in _tkinter
2610 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002611
2612- Fix memory management errors in Merge() and Tkapp_Call() routines.
2613
2614- Several changes were made to cStringIO to make it compatible with
2615 the file-like object interface and with StringIO. If operations are
2616 performed on a closed object, an exception is raised. The truncate
2617 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002618 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002619
2620- There were many changes made to the linuxaudiodev module and its
2621 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002622 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002623
2624 Note that this module is named poorly, because it should work
2625 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002626 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002627
2628 The module now raises exceptions when errors occur instead of
2629 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2630 audio) and defines a getptr() method that calls the
2631 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2632
2633- The library_version attribute, introduced in an earlier beta, was
2634 removed because it can not be supported with early versions of the C
2635 readline library, which provides no way to determine the version at
2636 compile-time.
2637
2638- The binascii module is now enabled on Win64.
2639
Tim Peters46446d62000-10-09 21:19:31 +00002640- tokenize.py no longer suffers "recursion depth" errors when parsing
2641 programs with very long string literals.
2642
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002643Internals
2644
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002645- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002646 which is called when the interpreter starts up to determine where
2647 the standard library is installed. These vulnerabilities affect all
2648 previous versions of Python and can be exploited by setting very
2649 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2650 setuid Python script, although use of the wrapper in
2651 Misc/setuid-prog.c will eliminate the vulnerability.
2652
2653- Fixed garbage collection bugs in instance creation that were
2654 triggered when errors occurred during initialization. The solution,
2655 applied in cPickle and in PyInstance_New(), is to call
2656 PyObject_GC_Init() after the initialization of the object's
2657 container attributes is complete.
2658
2659- pyexpat adds definitions of PyModule_AddStringConstant and
2660 PyModule_AddObject if the Python version is less than 2.0, which
2661 provides compatibility with PyXML on Python 1.5.2.
2662
2663- If the platform has a bogus definition for LONG_BIT (the number of
2664 bits in a long), an error will be reported at compile time.
2665
2666- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2667 collection crashes and possibly other, unreported crashes.
2668
2669- Fixed a memory leak in _PyUnicode_Fini().
2670
2671Build issues
2672
2673- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002674 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002675 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002676
2677- The mmap.PAGESIZE constant is now initialized using sysconf when
2678 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2679
2680- The md5 file should now compile on all platforms.
2681
2682- The select module now compiles on platforms that do not define
2683 POLLRDNORM and related constants.
2684
2685- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002686 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002687
Jeremy Hylton10921202000-10-09 18:34:12 +00002688- BeOS: A number of changes were made to the build and installation
2689 process. ar-fake now operates on a directory of object files.
2690 dl_export.h is gone, and its macros now appear on the mwcc command
2691 line during build on PPC BeOS.
2692
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002693- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002694 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002695
2696- Cygwin: Support for shared libraries, Tkinter, and sockets.
2697
2698- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2699
2700Tools and other miscellany
2701
2702- Removed debugging prints from main used with freeze.
2703
Tim Peters46446d62000-10-09 21:19:31 +00002704- IDLE auto-indent no longer crashes when it encounters Unicode
2705 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002706
2707What's new in 2.0 beta 2 (since beta 1)?
2708========================================
2709
2710Core language, builtins, and interpreter
2711
Tim Peters482c0212000-09-26 06:33:09 +00002712- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002713 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002714
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002715- Add -h and -V command line options to print the usage message and
2716 Python version number and exit immediately.
2717
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002718- eval() and exec accept Unicode objects as code parameters.
2719
2720- getattr() and setattr() now also accept Unicode objects for the
2721 attribute name, which are converted to strings using the default
2722 encoding before lookup.
2723
2724- Multiplication on string and Unicode now does proper bounds
2725 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2726 string is too long."
2727
2728- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002729 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002730
Jeremy Hylton1b618592000-09-26 05:32:36 +00002731
2732Standard library and extensions
2733
Guido van Rossum5b08f132001-04-16 02:05:23 +00002734- socket module: the OpenSSL code now adds support for RAND_status()
2735 and EGD (Entropy Gathering Device).
2736
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002737- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002738 argument checking; it still takes no arguments.
2739
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002740- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002741
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002742- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002743
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002744- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002745
2746- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002747 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002748
2749- copy: Copy Unicode objects atomically.
2750
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002751- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002752
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002753- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002754
Fred Drake67233bc2000-09-26 16:40:27 +00002755- dbm: Add get() and setdefault() methods to dbm object. Add constant
2756 `library' to module that names the library used. Added doc strings
2757 and method names to error messages. Uses configure to determine
2758 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2759 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002760
2761- distutils: Update to version 0.9.3.
2762
2763- dl: Add several dl.RTLD_ constants.
2764
2765- fpectl: Now supported on FreeBSD.
2766
2767- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2768 found by the collector will be saved in gc.garbage. This is useful
2769 for debugging a program that creates reference cycles.
2770
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002771- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002772 of HTTP class. Do not close socket on zero-length response. Do not
2773 crash when server sends invalid content-length header.
2774
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002775- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002776
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002777- marshal: When reading a short, sign-extend on platforms where shorts
2778 are bigger than 16 bits. When reading a long, repair the unportable
2779 sign extension that was being done for 64-bit machines. (It assumed
2780 that signed right shift sign-extends.)
2781
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002782- operator: Add contains(), invert(), __invert__() as aliases for
2783 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002784
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002785- os: Add support for popen2() and popen3() on all platforms where
2786 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002787
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002788- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002789 clicking on a file in Explorer (or passing the file name to the
2790 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002791
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002792- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002793 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002794
2795- pickle: Now raises ValueError when an invalid pickle that contains
2796 a non-string repr where a string repr was expected. This behavior
2797 matches cPickle.
2798
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002799- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002800
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002801- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002802
2803- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002804 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002805 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002806
2807- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002808 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002809
2810- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002811 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002812 few cycles during startup since the first call to
2813 setdefaultencoding() will initialize the codec registry and the
2814 encodings package.
2815
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002816- socket: Support for size hint in readlines() method of object returned
2817 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002818
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002819- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002820 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002821 is followed by whitespace.
2822
Tim Petersa3a3a032000-11-30 05:22:44 +00002823- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002824
2825- struct: Check ranges for bytes and shorts.
2826
2827- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002828 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002829
2830- Tkinter: Image objects are now guaranteed to have unique ids. Set
2831 event.delta to zero if Tk version doesn't support mousewheel.
2832 Removed some debugging prints.
2833
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002834- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002835
Fred Drake67233bc2000-09-26 16:40:27 +00002836- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002837 which works around a bug in Norton AntiVirus 2000 that leads directly
2838 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002839
2840- xml: New version detection code allows PyXML to override standard
2841 XML package if PyXML version is greater than 0.6.1.
2842
Fred Drake64bb3802000-09-26 16:21:35 +00002843- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2844 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2845 tree only for nodes which are sufficiently interesting to a specific
2846 application. Does not provide the HTML-specific extensions. Still
2847 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002848
Fred Drake64bb3802000-09-26 16:21:35 +00002849- xml.sax: SAX 2 support for Python, including all the handler
2850 interfaces needed to process XML 1.0 compliant XML. Some
2851 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002852
Fred Drake64bb3802000-09-26 16:21:35 +00002853- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2854 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002855
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002856
Jeremy Hylton1b618592000-09-26 05:32:36 +00002857C API
2858
2859- Add three new convenience functions for module initialization --
2860 PyModule_AddObject(), PyModule_AddIntConstant(), and
2861 PyModule_AddStringConstant().
2862
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002863- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002864 removed and add #error to Python.h if NULL isn't defined after
2865 #include of stdio.h.
2866
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002867- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002868 backwards compatibility (at the source level) with old extensions.
2869
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002870- A wrapper API was added for signal() and sigaction(). Instead of
2871 either function, always use PyOS_getsig() to get a signal handler
2872 and PyOS_setsig() to set one. A new convenience typedef
2873 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002875- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002876 internal data buffer and size of a string object -- or the default
2877 encoded version of a Unicode object.
2878
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002879- PyString_Size() and PyString_AsString() accept Unicode objects.
2880
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002881- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002882 exists). INT_MAX and LONG_MAX will always be defined, even if
2883 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002884
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002885- PyFloat_FromString takes a second argument, pend, that was
2886 effectively useless. It is now officially useless but preserved for
2887 backwards compatibility. If the pend argument is not NULL, *pend is
2888 set to NULL.
2889
2890- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2891 for the attribute name. See note on getattr() above.
2892
2893- A few bug fixes to argument processing for Unicode.
2894 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2895 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2896 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002897 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002898
2899- Py_BuildValue accepts B format (for bgen-generated code).
2900
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002901
Jeremy Hylton1b618592000-09-26 05:32:36 +00002902Internals
2903
2904- On Unix, fix code for finding Python installation directory so that
2905 it works when argv[0] is a relative path.
2906
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002907- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002908 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002909 rather than by generating a copy of the object.
2910
Tim Peters482c0212000-09-26 06:33:09 +00002911- Several of the internal Unicode tables are much smaller now, and
2912 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002913
Jeremy Hylton97693b02000-09-26 17:42:51 +00002914- In the garbage collector: Fixed bug in collection of tuples. Fixed
2915 bug that caused some instances to be removed from the container set
2916 while they were still live. Fixed parsing in gc.set_debug() for
2917 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002918
2919- Fixed refcount problem in instance deallocation that only occurred
2920 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2921
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002922- On Windows, getpythonregpath is now protected against null data in
2923 registry key.
2924
2925- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002926 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002927
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002928
Jeremy Hylton1b618592000-09-26 05:32:36 +00002929Build and platform-specific issues
2930
2931- Better support of GNU Pth via --with-pth configure option.
2932
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002933- Python/C API now properly exposed to dynamically-loaded extension
2934 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002935
2936- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2937 Don't define MS_SYNC to be zero when it is undefined. Added missing
2938 prototypes in posixmodule.c.
2939
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002940- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002941 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002942
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002943- Fix largefile support on older NetBSD systems and OpenBSD by adding
2944 define for TELL64.
2945
2946
2947Tools and other miscellany
2948
2949- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2950
2951- freeze: The modulefinder now works with 2.0 opcodes.
2952
Tim Petersa3a3a032000-11-30 05:22:44 +00002953- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002954 Move hackery of sys.argv until after the Tk instance has been
2955 created, which allows the application-specific Tkinter
2956 initialization to be executed if present; also pass an explicit
2957 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002958
Jeremy Hylton1b618592000-09-26 05:32:36 +00002959
2960What's new in 2.0 beta 1?
2961=========================
2962
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002963Source Incompatibilities
2964------------------------
2965
2966None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2967such as single-argument append(), connect() and bind(), and changes to
2968str(long) and repr(float).
2969
2970
2971Binary Incompatibilities
2972------------------------
2973
2974- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2975with Python 2.0; these extensions will have to be rebuilt for Python
29762.0.
2977
2978- On Windows, attempting to import a third party extension built for
2979Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2980can do about this. Check your PYTHONPATH environment variable!
2981
2982- Python bytecode files (*.pyc and *.pyo) are not compatible between
2983releases.
2984
2985
2986Overview of Changes Since 1.6
2987-----------------------------
2988
2989There are many new modules (including brand new XML support through
2990the xml package, and i18n support through the gettext module); a list
2991of all new modules is included below. Lots of bugs have been fixed.
2992
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002993The process for making major new changes to the language has changed
2994since Python 1.6. Enhancements must now be documented by a Python
2995Enhancement Proposal (PEP) before they can be accepted.
2996
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002997There are several important syntax enhancements, described in more
2998detail below:
2999
3000 - Augmented assignment, e.g. x += 1
3001
3002 - List comprehensions, e.g. [x**2 for x in range(10)]
3003
3004 - Extended import statement, e.g. import Module as Name
3005
3006 - Extended print statement, e.g. print >> file, "Hello"
3007
3008Other important changes:
3009
3010 - Optional collection of cyclical garbage
3011
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003012Python Enhancement Proposal (PEP)
3013---------------------------------
3014
3015PEP stands for Python Enhancement Proposal. A PEP is a design
3016document providing information to the Python community, or describing
3017a new feature for Python. The PEP should provide a concise technical
3018specification of the feature and a rationale for the feature.
3019
3020We intend PEPs to be the primary mechanisms for proposing new
3021features, for collecting community input on an issue, and for
3022documenting the design decisions that have gone into Python. The PEP
3023author is responsible for building consensus within the community and
3024documenting dissenting opinions.
3025
3026The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003027
3028Augmented Assignment
3029--------------------
3030
3031This must have been the most-requested feature of the past years!
3032Eleven new assignment operators were added:
3033
Guido van Rossume905e952000-09-05 12:42:46 +00003034 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003035
3036For example,
3037
3038 A += B
3039
3040is similar to
3041
3042 A = A + B
3043
3044except that A is evaluated only once (relevant when A is something
3045like dict[index].attr).
3046
3047However, if A is a mutable object, A may be modified in place. Thus,
3048if A is a number or a string, A += B has the same effect as A = A+B
3049(except A is only evaluated once); but if a is a list, A += B has the
3050same effect as A.extend(B)!
3051
3052Classes and built-in object types can override the new operators in
3053order to implement the in-place behavior; the not-in-place behavior is
3054used automatically as a fallback when an object doesn't implement the
3055in-place behavior. For classes, the method name is derived from the
3056method name for the corresponding not-in-place operator by inserting
3057an 'i' in front of the name, e.g. __iadd__ implements in-place
3058__add__.
3059
3060Augmented assignment was implemented by Thomas Wouters.
3061
3062
3063List Comprehensions
3064-------------------
3065
3066This is a flexible new notation for lists whose elements are computed
3067from another list (or lists). The simplest form is:
3068
3069 [<expression> for <variable> in <sequence>]
3070
Guido van Rossum56db0952000-09-06 23:34:25 +00003071For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003072This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003073
3074You can also add a condition:
3075
3076 [<expression> for <variable> in <sequence> if <condition>]
3077
3078For example, [w for w in words if w == w.lower()] would yield the list
3079of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003080than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003081
3082You can also have nested for loops and more than one 'if' clause. For
3083example, here's a function that flattens a sequence of sequences::
3084
3085 def flatten(seq):
3086 return [x for subseq in seq for x in subseq]
3087
3088 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3089
3090This prints
3091
3092 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3093
3094List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003095Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003096
3097
3098Extended Import Statement
3099-------------------------
3100
3101Many people have asked for a way to import a module under a different
3102name. This can be accomplished like this:
3103
3104 import foo
3105 bar = foo
3106 del foo
3107
3108but this common idiom gets old quickly. A simple extension of the
3109import statement now allows this to be written as follows:
3110
3111 import foo as bar
3112
3113There's also a variant for 'from ... import':
3114
3115 from foo import bar as spam
3116
3117This also works with packages; e.g. you can write this:
3118
3119 import test.regrtest as regrtest
3120
3121Note that 'as' is not a new keyword -- it is recognized only in this
3122context (this is only possible because the syntax for the import
3123statement doesn't involve expressions).
3124
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003125Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003126
3127
3128Extended Print Statement
3129------------------------
3130
3131Easily the most controversial new feature, this extension to the print
3132statement adds an option to make the output go to a different file
3133than the default sys.stdout.
3134
3135For example, to write an error message to sys.stderr, you can now
3136write:
3137
3138 print >> sys.stderr, "Error: bad dog!"
3139
3140As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003141evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003142
3143 print >> None, "Hello world"
3144
3145is equivalent to
3146
3147 print "Hello world"
3148
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003149Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003150
3151
3152Optional Collection of Cyclical Garbage
3153---------------------------------------
3154
3155Python is now equipped with a garbage collector that can hunt down
3156cyclical references between Python objects. It's no replacement for
3157reference counting; in fact, it depends on the reference counts being
3158correct, and decides that a set of objects belong to a cycle if all
3159their reference counts can be accounted for from their references to
3160each other. This devious scheme was first proposed by Eric Tiedemann,
3161and brought to implementation by Neil Schemenauer.
3162
3163There's a module "gc" that lets you control some parameters of the
3164garbage collection. There's also an option to the configure script
3165that lets you enable or disable the garbage collection. In 2.0b1,
3166it's on by default, so that we (hopefully) can collect decent user
3167experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003168performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003169off by default in the final 2.0 release.
3170
3171
3172Smaller Changes
3173---------------
3174
3175A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3176map(None, seq1, seq2, ...) when the sequences have the same length;
3177i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3178the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003179zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003180
3181sys.version_info is a tuple (major, minor, micro, level, serial).
3182
3183Dictionaries have an odd new method, setdefault(key, default).
3184dict.setdefault(key, default) returns dict[key] if it exists; if not,
3185it sets dict[key] to default and returns that value. Thus:
3186
3187 dict.setdefault(key, []).append(item)
3188
3189does the same work as this common idiom:
3190
3191 if not dict.has_key(key):
3192 dict[key] = []
3193 dict[key].append(item)
3194
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003195There are two new variants of SyntaxError that are raised for
3196indentation-related errors: IndentationError and TabError.
3197
3198Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3199escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003200
3201The limits on the size of expressions and file in Python source code
3202have been raised from 2**16 to 2**32. Previous versions of Python
3203were limited because the maximum argument size the Python VM accepted
3204was 2**16. This limited the size of object constructor expressions,
3205e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3206limit was raised thanks to a patch by Charles Waldman that effectively
3207fixes the problem. It is now much more likely that you will be
3208limited by available memory than by an arbitrary limit in Python.
3209
3210The interpreter's maximum recursion depth can be modified by Python
3211programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3212limit is the maximum number of recursive calls that can be made by
3213Python code. The limit exists to prevent infinite recursion from
3214overflowing the C stack and causing a core dump. The default value is
32151000. The maximum safe value for a particular platform can be found
3216by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003217
3218New Modules and Packages
3219------------------------
3220
3221atexit - for registering functions to be called when Python exits.
3222
3223imputil - Greg Stein's alternative API for writing custom import
3224hooks.
3225
3226pyexpat - an interface to the Expat XML parser, contributed by Paul
3227Prescod.
3228
3229xml - a new package with XML support code organized (so far) in three
3230subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3231would fill a volume. There's a special feature whereby a
3232user-installed package named _xmlplus overrides the standard
3233xmlpackage; this is intended to give the XML SIG a hook to distribute
3234backwards-compatible updates to the standard xml package.
3235
3236webbrowser - a platform-independent API to launch a web browser.
3237
3238
Guido van Rossume905e952000-09-05 12:42:46 +00003239Changed Modules
3240---------------
3241
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003242array -- new methods for array objects: count, extend, index, pop, and
3243remove
3244
3245binascii -- new functions b2a_hex and a2b_hex that convert between
3246binary data and its hex representation
3247
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003248calendar -- Many new functions that support features including control
3249over which day of the week is the first day, returning strings instead
3250of printing them. Also new symbolic constants for days of week,
3251e.g. MONDAY, ..., SUNDAY.
3252
3253cgi -- FieldStorage objects have a getvalue method that works like a
3254dictionary's get method and returns the value attribute of the object.
3255
3256ConfigParser -- The parser object has new methods has_option,
3257remove_section, remove_option, set, and write. They allow the module
3258to be used for writing config files as well as reading them.
3259
3260ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003261optionally support the RFC 959 REST command.
3262
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003263gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003264
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003265httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3266the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003267
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003268locale -- implement getdefaultlocale for Win32 and Macintosh
3269
3270marshal -- no longer dumps core when marshaling deeply nested or
3271recursive data structures
3272
3273os -- new functions isatty, seteuid, setegid, setreuid, setregid
3274
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003275os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3276support under Unix.
3277
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003278os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003279
3280os.path -- fix semantics of os.path.commonprefix
3281
3282smtplib -- support for sending very long messages
3283
3284socket -- new function getfqdn()
3285
3286readline -- new functions to read, write and truncate history files.
3287The readline section of the library reference manual contains an
3288example.
3289
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003290select -- add interface to poll system call
3291
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003292shutil -- new copyfileobj function
3293
3294SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3295HTTP server.
3296
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003297Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003298
3299urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003300e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003301
3302whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003303
3304
3305Obsolete Modules
3306----------------
3307
3308None. However note that 1.6 made a whole slew of modules obsolete:
3309stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3310poly, zmod, strop, util, whatsound.
3311
3312
3313Changed, New, Obsolete Tools
3314----------------------------
3315
Tim Peters8b092332000-09-05 20:15:25 +00003316None.
Guido van Rossume905e952000-09-05 12:42:46 +00003317
3318
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003319C-level Changes
3320---------------
3321
3322Several cleanup jobs were carried out throughout the source code.
3323
3324All C code was converted to ANSI C; we got rid of all uses of the
3325Py_PROTO() macro, which makes the header files a lot more readable.
3326
3327Most of the portability hacks were moved to a new header file,
3328pyport.h; several other new header files were added and some old
3329header files were removed, in an attempt to create a more rational set
3330of header files. (Few of these ever need to be included explicitly;
3331they are all included by Python.h.)
3332
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003333Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003334and Win64, especially for the new Intel Itanium processor. Mick also
3335added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003336
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003337The C APIs to return an object's size have been update to consistently
3338use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3339previous versions, the abstract interfaces used PyXXX_Length and the
3340concrete interfaces used PyXXX_Size. The old names,
3341e.g. PyObject_Length, are still available for backwards compatibility
3342at the API level, but are deprecated.
3343
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003344The PyOS_CheckStack function has been implemented on Windows by
3345Fredrik Lundh. It prevents Python from failing with a stack overflow
3346on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003347
3348The GC changes resulted in creation of two new slots on object,
3349tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003350the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003351
3352The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003353C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003354
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003355PyErr_Format has been updated to automatically calculate the size of
3356the buffer needed to hold the formatted result string. This change
3357prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003358
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003359New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003360
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003361PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3362that are the same as their non-Ex counterparts except they take an
3363extra flag argument that tells them to close the file when done.
3364
3365XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003366
Tim Peters8b092332000-09-05 20:15:25 +00003367
3368Windows Changes
3369---------------
3370
3371New popen2/popen3/peopen4 in os module (see Changed Modules above).
3372
3373os.popen is much more usable on Windows 95 and 98. See Microsoft
3374Knowledge Base article Q150956. The Win9x workaround described there
3375is implemented by the new w9xpopen.exe helper in the root of your
3376Python installation. Note that Python uses this internally; it is not
3377a standalone program.
3378
3379Administrator privileges are no longer required to install Python
3380on Windows NT or Windows 2000. If you have administrator privileges,
3381Python's registry info will be written under HKEY_LOCAL_MACHINE.
3382Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003383under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003384uses of Python, but will prevent some advanced uses from working
3385(for example, running a Python script as an NT service, or possibly
3386from CGI).
3387
3388[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3389installer; instead, it installs the needed Tcl/Tk files directly in the
3390Python directory. If you already have a Tcl/Tk installation, this
3391wastes some disk space (about 4 Megs) but avoids problems with
3392conflicting Tcl/Tk installations, and makes it much easier for Python
3393to ensure that Tcl/Tk can find all its files.
3394
3395[This was new in 1.6] The Windows installer now installs by default in
3396\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3397
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003398
3399Updates to the changes between 1.5.2 and 1.6
3400--------------------------------------------
3401
3402The 1.6 NEWS file can't be changed after the release is done, so here
3403is some late-breaking news:
3404
3405New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3406and changes to getlocale() and setlocale().
3407
3408The new module is now enabled per default.
3409
3410It is not true that the encodings codecs cannot be used for normal
3411strings: the string.encode() (which is also present on 8-bit strings
3412!) allows using them for 8-bit strings too, e.g. to convert files from
3413cp1252 (Windows) to latin-1 or vice-versa.
3414
3415Japanese codecs are available from Tamito KAJIYAMA:
3416http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3417
3418
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003419======================================================================