blob: 936369419104bb112d78334ea9415f9907aaebd1 [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
Neil Schemenauer89e3ee02002-04-26 01:58:53 +00009- The assert statement no longer tests __debug__ at runtime. This means
10 that assert statements cannot be disabled by assigning a false value
11 to __debug__.
12
Walter Dörwald068325e2002-04-15 13:36:47 +000013- A method zfill() was added to str and unicode, that fills a numeric
14 string to the left with zeros. For example,
15 "+123".zfill(6) -> "+00123".
16
Guido van Rossum862fe3c2002-04-15 12:36:47 +000017- Complex numbers supported divmod() and the // and % operators, but
18 these make no sense. Since this was documented, they're being
19 deprecated now.
20
Guido van Rossum49042042002-04-13 00:59:05 +000021- String methods lstrip(), rstrip() and strip() now take an optional
22 argument that specifies the characters to strip. For example,
23 "Foo!!!?!?!?".rstrip("?!") -> "Foo".
24
Guido van Rossumc69343b2002-04-12 19:22:48 +000025- Added a new dict method pop(key). This removes and returns the
26 value corresponding to key. [SF patch #539949]
27
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000028- Changed new-style class instantiation so that when C's __new__
29 method returns something that's not a C instance, its __init__ is
30 not called. [SF bug #537450]
31
Guido van Rossum181e41a2002-04-06 00:23:25 +000032- Fixed super() to work correctly with class methods. [SF bug #535444]
33
Guido van Rossum47834462002-04-04 15:21:33 +000034- A new built-in type, bool, has been added, as well as built-in
35 names for its two values, True and False. Comparisons and sundry
36 other operations that return a truth value have been changed to
37 return a bool instead. Read PEP 285 for an explanantion of why this
38 is backward compatible.
39
Guido van Rossum95b62a62002-03-29 01:07:24 +000040- Fixed two bugs reported as SF #535905: under certain conditions,
41 deallocating a deeply nested structure could cause a segfault in the
42 garbage collector, due to interaction with the "trashcan" code;
43 access to the current frame during destruction of a local variable
44 could access a pointer to freed memory.
45
Neil Schemenauer9d50d132002-03-22 17:06:59 +000046- The optional object allocator has been enabled by default.
47
Guido van Rossum8c842552002-03-14 23:05:54 +000048- If you try to pickle an instance of a class that has __slots__ but
49 doesn't define or override __getstate__, a TypeError is now raised.
50 This is done by adding a bozo __getstate__ to the class that always
51 raises TypeError. (Before, this would appear to be pickled, but the
52 state of the slots would be lost.)
53
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000054- PyErr_Display will provide file and line information for all exceptions
55 that have an attribute print_file_and_line, not just SyntaxErrors.
56
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000057- The UTF-8 codec will now encode and decode Unicode surrogates
58 correctly and without raising exceptions for unpaired ones.
59
Neal Norwitz649b7592002-01-01 19:07:13 +000060- file.xreadlines() now raises a ValueError if the file is closed:
61 Previously, an xreadlines object was returned which would raise
62 a ValueError when the xreadlines.next() method was called.
63
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000064- posix.killpg has been added where available.
65
Neal Norwitz0c766a02002-03-27 13:03:09 +000066- sys.exit() inadvertantly allowed more than one argument.
67 An exception will now be raised if more than one argument is used.
68
Tim Petersaf8446f2001-12-21 21:36:50 +000069Extension modules
70
Anthony Baxter83888952002-04-23 02:11:05 +000071- The bsddb.*open functions can now take 'None' as a filename.
72 This will create a temporary in-memory bsddb that won't be
73 written to disk.
74
Martin v. Löwis06a83e92002-04-14 10:19:44 +000075- posix.mknod was added.
76
Martin v. Löwis2e64c342002-03-27 18:49:02 +000077- The locale module now exposes the C library's gettext interface.
78
Tim Petersfbf74f22002-03-14 19:06:01 +000079- A security hole ("double free") was found in zlib-1.1.3, a popular
80 third party compression library used by some Python modules. The
81 hole was quickly plugged in zlib-1.1.4, and the Windows build of
82 Python now ships with zlib-1.1.4.
83
Martin v. Löwis688357e2002-04-08 21:28:20 +000084- pwd, grp, and resource return enhanced tuples now, with symbolic
85 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000086
Martin v. Löwis99866332002-03-01 10:27:01 +000087- array.array is now a type object. A new format character
88 'u' indicates Py_UNICODE arrays. For those, .tounicode and
89 .fromunicode methods are available. Arrays now support __iadd__
90 and __imul__.
91
Neal Norwitze790eae2002-01-01 21:14:12 +000092- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000093 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
94 is called.
95
Tim Petersaf8446f2001-12-21 21:36:50 +000096Library
97
Guido van Rossum256705b2002-04-23 13:29:43 +000098- New Text.dump() method in Tkinter module.
99
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000100- New distutils commands for building packagers were added to
101 support pkgtool on Solaris and swinstall on HP-UX.
102
103- distutils now has a new abstract binary packager base class
104 command/bdist_packager, which simplifies writing packagers.
105 This will hopefully provide the missing bits to encourage
106 people to submit more packagers, e.g. for Debian, FreeBSD
107 and other systems.
108
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000109- The UTF-16, -LE and -BE now raise a NotImplementedError
110 for all calls to .readline(). Previously, they used to just
111 produce garbage or fail with an encoding error -- UTF-16 is
112 a 2-byte encoding and the C lib's line reading APIs don't
113 work well with these.
114
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000115- compileall now supports quiet operation.
116
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000117- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
118 connections.
119
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000120- socket module: the SSL support was broken out of the main
121 _socket module C helper and placed into a new _ssl helper
122 which now gets imported by socket.py if available and working.
123
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000124- encodings package: added aliases for all supported IANA character
125 sets
126
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000127- ftplib: to safeguard the user's privacy, anonymous login will use
128 "anonymous@" as default password, rather than the real user and host
129 name.
130
Fred Drake36736122002-01-10 13:50:31 +0000131- webbrowser: tightened up the command passed to os.system() so that
132 arbitrary shell code can't be executed because a bogus URL was
133 passed in.
134
Tim Peters11bd9942002-02-01 00:52:29 +0000135- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000136 gettext.find an optional all argument. Translations will now fallback
137 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000138
Martin v. Löwis9668b932002-01-12 11:27:42 +0000139- distutils bdist commands now offer a --skip-build option.
140
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000141- warnings.warn now accepts a Warning instance as first argument.
142
Fred Drakefed7e852002-04-04 19:36:15 +0000143- The xml.sax.expatreader.ExpatParser class will no longer create
144 circular references by using itself as the locator that gets passed
145 to the content handler implementation. [SF bug #535474]
146
Tim Petersaf8446f2001-12-21 21:36:50 +0000147Tools/Demos
148
Marc-André Lemburg46260092002-04-04 16:17:11 +0000149- freeze.py now produces binaries which can import shared modules,
150 unlike before when this failed due to missing symbol exports in
151 the generated binary.
152
Tim Petersaf8446f2001-12-21 21:36:50 +0000153Build
154
Tim Peters639295f2002-04-21 07:30:30 +0000155- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
156 say how or when to configure it, or how to turn it off.
157
Martin v. Löwis1142de32002-03-29 16:28:31 +0000158- On Unix, a shared libpython2.3.so can be created with --enable-shared.
159
Tim Peters8deda702002-03-30 10:06:07 +0000160- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
161 preprocessor symbols were eliminated. The internal decisions they
162 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000163
Tim Petersaf8446f2001-12-21 21:36:50 +0000164C API
165
Neil Schemenauer9344b142002-04-12 23:00:08 +0000166- The type of tp_free has been changed from "void (*)(PyObject *)" to
167 "void (*)(void *)".
168
169- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
170
Guido van Rossum0986d822002-04-08 01:38:42 +0000171- A type can now inherit its metatype from its base type. Previously,
172 when PyType_Ready() was called, if ob_type was found to be NULL, it
173 was always set to &PyType_Type; now it is set to base->ob_type,
174 where base is tp_base, defaulting to &PyObject_Type.
175
176- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
177
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000178- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
179 functions will be allocated using pymalloc if it is enabled. These
180 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
181 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
182 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
183 PyCore_* family of APIs have been removed.
184
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000185- The "u#" parser marker will now pass through Unicode object as-is
186 without going through the buffer API.
187
Martin v. Löwis7198a522002-01-01 19:59:11 +0000188- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
189
Tim Peters10a3bb52001-12-25 19:07:38 +0000190- An old #define of ANY as void has been removed from pyport.h. This
191 hasn't been used since Python's pre-ANSI days, and the #define has
192 been marked as obsolete since then. SF bug 495548 says it created
193 conflicts with other packages, so keeping it around wasn't harmless.
194
Tim Petersaf8446f2001-12-21 21:36:50 +0000195- Because Python's magic number scheme broke on January 1st, we decided
196 to stop Python development. Thanks for all the fish!
197
Tim Petersfb05db22002-03-11 00:24:00 +0000198- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000199 scheme to a new one. See Python/import.c for details.
200
Tim Petersaf8446f2001-12-21 21:36:50 +0000201New platforms
202
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000203- GNU/Hurd is now supported.
204
Tim Petersaf8446f2001-12-21 21:36:50 +0000205Tests
206
207Windows
208
Tim Peters08e72952002-04-16 20:48:01 +0000209- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
210 of that has been fixed in the installer (disabled Wise's "delete in-
211 use files" uninstall option).
212
Guido van Rossum181e41a2002-04-06 00:23:25 +0000213- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
214
Tim Peters33187922002-04-04 20:02:04 +0000215- The installer now installs Start menu shortcuts under (the local
216 equivalent of) "All Users" when doing an Admin install.
217
Tim Petersfb05db22002-03-11 00:24:00 +0000218- file.truncate([newsize]) now works on Windows for all newsize values.
219 It used to fail if newsize didn't fit in 32 bits, reflecting a
220 limitation of MS _chsize (which is no longer used).
221
Tim Petersab034fa2002-02-01 11:27:43 +0000222- os.waitpid() is now implemented for Windows, and can be used to block
223 until a specified process exits. This is similar to, but not exactly
224 the same as, os.waitpid() on POSIX systems. If you're waiting for
225 a specific process whose pid was obtained from one of the spawn()
226 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000227 See the docs for details. The docs were changed to clarify that
228 spawn functions return, and waitpid requires, a process handle on
229 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000230
Tim Peters11bd9942002-02-01 00:52:29 +0000231- New tempfile.TemporaryFile implementation for Windows: this doesn't
232 need a TemproraryFileWrapper wrapper anymore, and should be immune
233 to a nasty problem: before 2.3, if you got a temp file on Windows, it
234 got wrapped in an object whose close() method first closed the
235 underlying file, then deleted the file. This usually worked fine.
236 However, the spawn family of functions on Windows create (at a low C
237 level) the same set of open files in the spawned process Q as were
238 open in the spawning process P. If a temp file f was among them, then
239 doing f.close() in P first closed P's C-level file handle on f, but Q's
240 C-level file handle on f remained open, so the attempt in P to delete f
241 blew up with a "Permission denied" error (Windows doesn't allow
242 deleting open files). This was surprising, subtle, and difficult to
243 work around.
244
245- The os module now exports all the symbolic constants usable with the
246 low-level os.open() on Windows: the new constants in 2.3 are
247 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
248 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
249 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
250 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
251 (so specify both if you want both; note that neither is useful unless
252 specified with O_CREAT too).
253
Tim Petersaf8446f2001-12-21 21:36:50 +0000254Mac
255
256
Tim Peters909c0912001-12-14 23:16:18 +0000257What's New in Python 2.2 final?
258Release date: 21-Dec-2001
259===============================
260
261Type/class unification and new-style classes
262
Barry Warsaw52acb492001-12-21 20:04:22 +0000263- pickle.py, cPickle: allow pickling instances of new-style classes
264 with a custom metaclass.
265
Tim Peters909c0912001-12-14 23:16:18 +0000266Core and builtins
267
Barry Warsaw52acb492001-12-21 20:04:22 +0000268- weakref proxy object: when comparing, unwrap both arguments if both
269 are proxies.
270
Tim Peters909c0912001-12-14 23:16:18 +0000271Extension modules
272
Barry Warsaw52acb492001-12-21 20:04:22 +0000273- binascii.b2a_base64(): fix a potential buffer overrun when encoding
274 very short strings.
275
276- cPickle: the obscure "fast" mode was suspected of causing stack
277 overflows on the Mac. Hopefully fixed this by setting the recursion
278 limit much smaller. If the limit is too low (it only affects
279 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
280 when compiling cPickle.c (or in pyconfig.h).
281
Tim Peters909c0912001-12-14 23:16:18 +0000282Library
283
Barry Warsaw52acb492001-12-21 20:04:22 +0000284- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
285 close or delete time).
286
287- rfc822.py: fixed a bug where the address '<>' was converted to None
288 instead of an empty string (also fixes the email.Utils module).
289
290- xmlrpclib.py: version 1.0.0; uses precision for doubles.
291
292- test suite: the pickle and cPickle tests were not executing any code
293 when run from the standard regresssion test.
294
Tim Peters909c0912001-12-14 23:16:18 +0000295Tools/Demos
296
297Build
298
299C API
300
301New platforms
302
303Tests
304
305Windows
306
Barry Warsaw52acb492001-12-21 20:04:22 +0000307- distutils package: fixed broken Windows installers (bdist_wininst).
308
309- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
310 instances are deleted at process exit time.
311
312- socket.py: prevent mysterious warnings when socket instances are
313 deleted at process exit time.
314
315- posixmodule.c: fix a Windows crash with stat() of a filename ending
316 in backslash.
317
Tim Peters909c0912001-12-14 23:16:18 +0000318Mac
319
Barry Warsaw52acb492001-12-21 20:04:22 +0000320- The Carbon toolbox modules have been upgraded to Universal Headers
321 3.4, and experimental CoreGraphics and CarbonEvents modules have
322 been added. All only for framework-enabled MacOSX.
323
Tim Peters909c0912001-12-14 23:16:18 +0000324
Tim Peters6272dfd2001-12-13 19:34:00 +0000325What's New in Python 2.2c1?
326Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000327===========================
328
329Type/class unification and new-style classes
330
Barry Warsaw06557452001-12-14 20:47:12 +0000331- Guido's tutorial introduction to the new type/class features has
332 been extensively updated. See
333
334 http://www.python.org/2.2/descrintro.html
335
336 That remains the primary documentation in this area.
337
Guido van Rossum33bab012001-12-05 22:45:48 +0000338- Fixed a leak: instance variables declared with __slots__ were never
339 deleted!
340
Guido van Rossum4b800852001-12-03 00:54:52 +0000341- The "delete attribute" method of descriptor objects is called
342 __delete__, not __del__. In previous releases, it was mistakenly
343 called __del__, which created an unfortunate overloading condition
344 with finalizers. (The "get attribute" and "set attribute" methods
345 are still called __get__ and __set__, respectively.)
346
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000347- Some subtle issues with the super built-in were fixed:
348
349 (a) When super itself is subclassed, its __get__ method would still
350 return an instance of the base class (i.e., of super).
351
352 (b) super(C, C()).__class__ would return C rather than super. This
353 is confusing. To fix this, I decided to change the semantics of
354 super so that it only applies to code attributes, not to data
355 attributes. After all, overriding data attributes is not
356 supported anyway.
357
358 (c) The __get__ method didn't check whether the argument was an
359 instance of the type used in creation of the super instance.
360
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000361- Previously, hash() of an instance of a subclass of a mutable type
362 (list or dictionary) would return some value, rather than raising
363 TypeError. This has been fixed. Also, directly calling
364 dict.__hash__ and list.__hash__ now raises the same TypeError
365 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000366
Guido van Rossumd331cb52001-12-05 19:46:42 +0000367- New-style objects now support deleting their __dict__. This is for
368 all intents and purposes equivalent to assigning a brand new empty
369 dictionary, but saves space if the object is not used further.
370
Tim Petersb3c9af12001-11-17 00:21:57 +0000371Core and builtins
372
Tim Peters3caca232001-12-06 06:23:26 +0000373- -Qnew now works as documented in PEP 238: when -Qnew is passed on
374 the command line, all occurrences of "/" use true division instead
375 of classic division. See the PEP for details. Note that "all"
376 means all instances in library and 3rd-party modules, as well as in
377 your own code. As the PEP says, -Qnew is intended for use only in
378 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000379 Note that test_coercion.py in the standard Python test suite fails
380 under -Qnew; this is expected, and won't be repaired until true
381 division becomes the default (in the meantime, test_coercion is
382 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000383
Fred Drake6c01e252001-12-14 17:08:12 +0000384- complex() now only allows the first argument to be a string
385 argument, and raises TypeError if either the second arg is a string
386 or if the second arg is specified when the first is a string.
387
Tim Petersb3c9af12001-11-17 00:21:57 +0000388Extension modules
389
Martin v. Löwis560da622001-11-24 09:24:51 +0000390- gc.get_referents was renamed to gc.get_referrers.
391
Tim Petersb3c9af12001-11-17 00:21:57 +0000392Library
393
Tim Peters25059d32001-12-07 20:35:43 +0000394- Functions in the os.spawn() family now release the global interpreter
395 lock around calling the platform spawn. They should always have done
396 this, but did not before 2.2c1. Multithreaded programs calling
397 an os.spawn function with P_WAIT will no longer block all Python threads
398 until the spawned program completes. It's possible that some programs
399 relies on blocking, although more likely by accident than by design.
400
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000401- webbrowser defaults to netscape.exe on OS/2 now.
402
Martin v. Löwis652e1912001-11-25 14:50:56 +0000403- Tix.ResizeHandle exposes detach_widget, hide, and show.
404
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000405- The charset alias windows_1252 has been added.
406
Barry Warsaw06557452001-12-14 20:47:12 +0000407- types.StringTypes is a tuple containing the defined string types;
408 usually this will be (str, unicode), but if Python was compiled
409 without Unicode support it will be just (str,).
410
411- The pulldom and minidom modules were synchronized to PyXML.
412
Tim Petersb3c9af12001-11-17 00:21:57 +0000413Tools/Demos
414
Barry Warsaw06557452001-12-14 20:47:12 +0000415- A new script called Tools/scripts/google.py was added, which fires
416 off a search on Google.
417
Tim Petersb3c9af12001-11-17 00:21:57 +0000418Build
419
Barry Warsaw06557452001-12-14 20:47:12 +0000420- Note that release builds of Python should arrange to define the
421 preprocessor symbol NDEBUG on the command line (or equivalent).
422 In the 2.2 pre-release series we tried to define this by magic in
423 Python.h instead, but it proved to cause problems for extension
424 authors. The Unix, Windows and Mac builds now all define NDEBUG in
425 release builds via cmdline (or equivalent) instead. Ports to
426 other platforms should do likewise.
427
Jack Jansen1999ef42001-12-06 21:47:20 +0000428- It is no longer necessary to use --with-suffix when building on a
429 case-insensitive file system (such as Mac OS X HFS+). In the build
430 directory an extension is used, but not in the installed python.
431
Tim Petersb3c9af12001-11-17 00:21:57 +0000432C API
433
Tim Petersf582b822001-12-11 18:51:08 +0000434- New function PyDict_MergeFromSeq2() exposes the builtin dict
435 constructor's logic for updating a dictionary from an iterable object
436 producing key-value pairs.
437
Tim Peterscffed4b2001-11-29 03:26:37 +0000438- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000439 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000440 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
441 dump core in some bad cases. This has been repaired. As a result,
442 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
443 previously went unchallenged.
444
Tim Petersb3c9af12001-11-17 00:21:57 +0000445New platforms
446
447Tests
448
449Windows
450
451Mac
452
Jack Jansenffa260f2001-12-06 21:14:00 +0000453- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
454 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000455
Barry Warsaw06557452001-12-14 20:47:12 +0000456- Changed logic for finding python home in Mac OS X framework Pythons.
457 Now sys.executable points to the executable again, in stead of to
458 the shared library. The latter is used only for locating the python
459 home.
460
461
Tim Peters84362bc2001-10-19 17:55:30 +0000462What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000463Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000464===========================
465
466Type/class unification and new-style classes
467
Guido van Rossum3d27df02001-11-15 20:27:54 +0000468- Multiple inheritance mixing new-style and classic classes in the
469 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000470
471 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000472 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000473
474 The MRO (method resolution order) for each base class is respected
475 according to its kind, but the MRO for the derived class is computed
476 using new-style MRO rules if any base clase is a new-style class.
477 This needs to be documented.
478
Tim Petersa427a2b2001-10-29 22:25:45 +0000479- The new builtin dictionary() constructor, and dictionary type, have
480 been renamed to dict. This reflects a decade of common usage.
481
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000482- dict() now accepts an iterable object producing 2-sequences. For
483 example, dict(d.items()) == d for any dictionary d. The argument,
484 and the elements of the argument, can be any iterable objects.
485
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000486- New-style classes can now have a __del__ method, which is called
487 when the instance is deleted (just like for classic classes).
488
Guido van Rossum12d955c2001-10-26 14:56:06 +0000489- Assignment to object.__dict__ is now possible, for objects that are
490 instances of new-style classes that have a __dict__ (unless the base
491 class forbids it).
492
Guido van Rossumc8e56452001-10-22 00:43:43 +0000493- Methods of built-in types now properly check for keyword arguments
494 (formerly these were silently ignored). The only built-in methods
495 that take keyword arguments are __call__, __init__ and __new__.
496
Guido van Rossum86443212001-10-27 22:28:54 +0000497- The socket function has been converted to a type; see below.
498
Tim Peters84362bc2001-10-19 17:55:30 +0000499Core and builtins
500
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000501- Assignment to __debug__ raises SyntaxError at compile-time. This
502 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000503 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000504
Guido van Rossum12d955c2001-10-26 14:56:06 +0000505- Clarified the error messages for unsupported operands to an operator
506 (like 1 + '').
507
Tim Peters84362bc2001-10-19 17:55:30 +0000508Extension modules
509
Tim Peters5ebfd362001-11-13 23:11:19 +0000510- mmap has a new keyword argument, "access", allowing a uniform way for
511 both Windows and Unix users to create read-only, write-through and
512 copy-on-write memory mappings. This was previously possible only on
513 Unix. A new keyword argument was required to support this in a
514 uniform way because the mmap() signuatures had diverged across
515 platforms. Thanks to Jay T Miller for repairing this!
516
Tim Peters169ded02001-11-03 19:57:21 +0000517- By default, the gc.garbage list now contains only those instances in
518 unreachable cycles that have __del__ methods; in 2.1 it contained all
519 instances in unreachable cycles. "Instances" here has been generalized
520 to include instances of both new-style and old-style classes.
521
Guido van Rossum12d955c2001-10-26 14:56:06 +0000522- The socket module defines a new method for socket objects,
523 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000524 send() until all data has been sent. Also, the socket function has
525 been converted to a subclassable type, like list and tuple (etc.)
526 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000527
528- Various bugfixes to the curses module. There is now a test suite
529 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000530
Guido van Rossum692adf12001-10-30 03:03:03 +0000531- binascii.b2a_base64 no longer places an arbitrary restriction of 57
532 bytes on its input.
533
Tim Peters84362bc2001-10-19 17:55:30 +0000534Library
535
Tim Peters5ebfd362001-11-13 23:11:19 +0000536- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000537 convenience function.
538
Tim Peters75335872001-11-03 19:35:43 +0000539- Symbolic group names in regular expressions must be unique. For
540 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
541 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000542 Python 2.2 detects this error at regexp compilation time;
543 previously, the error went undetected, and results were
544 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
545 pattern.subn() methods have been rewritten in C. Also, an
546 experimental function/method finditer() has been added, which works
547 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000548
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000549- Tix exposes more commands through the classes DirSelectBox,
550 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
551 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
552 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
553
Tim Peters98791af2001-10-23 01:59:54 +0000554- Traceback objects are now scanned by cyclic garbage collection, so
555 cycles created by casual use of sys.exc_info() no longer cause
556 permanent memory leaks (provided garbage collection is enabled).
557
Guido van Rossum49192142001-10-24 20:51:44 +0000558- os.extsep -- a new variable needed by the RISCOS support. It is the
559 separator used by extensions, and is '.' on all platforms except
560 RISCOS, where it is '/'. There is no need to use this variable
561 unless you have a masochistic desire to port your code to RISCOS.
562
Barry Warsaw012852b2001-11-16 16:17:27 +0000563- mimetypes.py has optional support for non-standard, but commonly
564 found types. guess_type() and guess_extension() now accept an
565 optional `strict' flag, defaulting to true, which controls whether
566 recognize non-standard types or not. A few non-standard types we
567 know about have been added. Also, when run as a script, there are
568 new -l and -e options.
569
570- statcache is now deprecated.
571
572- email.Utils.formatdate() now produces the preferred RFC 2822 style
573 dates with numeric timezones (it used to produce obsolete dates
574 hard coded to "GMT" timezone). An optional `localtime' flag is
575 added to produce dates in the local timezone, with daylight savings
576 time properly taken into account.
577
578- In pickle and cPickle, instead of masking errors in load() by
579 transforming them into SystemError, we let the original exception
580 propagate out. Also, implement support for __safe_for_unpickling__
581 in pickle, as it already was supported in cPickle.
582
Tim Peters84362bc2001-10-19 17:55:30 +0000583Tools/Demos
584
585Build
586
Barry Warsaw012852b2001-11-16 16:17:27 +0000587- The dbm module is built using libdb1 if available. The bsddb module
588 is built with libdb3 if available.
589
590- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
591
Tim Peters84362bc2001-10-19 17:55:30 +0000592C API
593
Tim Peters1fc240e2001-10-26 05:06:50 +0000594- New function PySequence_Fast_GET_SIZE() returns the size of a non-
595 NULL result from PySequence_Fast(), more quickly than calling
596 PySequence_Size().
597
Barry Warsaw012852b2001-11-16 16:17:27 +0000598- New argument unpacking function PyArg_UnpackTuple() added.
599
600- New functions PyObject_CallFunctionObjArgs() and
601 PyObject_CallMethodObjArgs() have been added to make it more
602 convenient and efficient to call functions and methods from C.
603
604- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
605 possible that this will propagate errors it didn't before.
606
607- New function PyObject_CheckReadBuffer(), which returns true if its
608 argument supports the single-segment readable buffer interface.
609
Tim Peters84362bc2001-10-19 17:55:30 +0000610New platforms
611
Guido van Rossum86443212001-10-27 22:28:54 +0000612- We've finally confirmed that this release builds on HP-UX 11.00,
613 *with* threads, and passes the test suite.
614
Tim Peters7a33d8b2001-11-05 02:51:07 +0000615- Thanks to a series of patches from Michael Muller, Python may build
616 again under OS/2 Visual Age C++.
617
Guido van Rossum49192142001-10-24 20:51:44 +0000618- Updated RISCOS port by Dietmar Schwertberger.
619
Tim Peters84362bc2001-10-19 17:55:30 +0000620Tests
621
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000622- Added a test script for the curses module. It isn't run automatically;
623 regrtest.py must be run with '-u curses' to enable it.
624
Tim Peters84362bc2001-10-19 17:55:30 +0000625Windows
626
Barry Warsaw012852b2001-11-16 16:17:27 +0000627Mac
628
629- PythonScript has been moved to unsupported and is slated to be
630 removed completely in the next release.
631
632- It should now be possible to build applets that work on both OS9 and
633 OSX.
634
635- The core is now linked with CoreServices not Carbon; as a side
636 result, default 8bit encoding on OSX is now ASCII.
637
638- Python should now build on OSX 10.1.1
639
Tim Peters84362bc2001-10-19 17:55:30 +0000640
Tim Petersabf925f2001-09-28 21:53:42 +0000641What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000642Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000643===========================
644
645Type/class unification and new-style classes
646
Guido van Rossum687ae002001-10-15 22:03:32 +0000647- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000648 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000649 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000650 remains: the __dict__ of a new-style class is a read-only proxy; you
651 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000652 __defined__ attribute of new-style types no longer exists, for lack
653 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000654 future a __cache__ may be resurrected with a similar function, if I
655 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000656
Tim Peters1c9ca872001-10-04 06:43:12 +0000657- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
658 always returned None, even when there was a class docstring).
659
660- doctest now finds and runs docstrings attached to new-style classes,
661 class methods, static methods, and properties.
662
Guido van Rossum9074ef62001-10-16 21:34:49 +0000663Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000664
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000665- A very subtle syntactical pitfall in list comprehensions was fixed.
666 For example: [a+b for a in 'abc', for b in 'def']. The comma in
667 this example is a mistake. Previously, this would silently let 'a'
668 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
669 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
670 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
671 Note that [a for a in <singleton>] is a convoluted way to say
672 [<singleton>] anyway, so it's not like any expressiveness is lost.
673
Guido van Rossum9074ef62001-10-16 21:34:49 +0000674- getattr(obj, name, default) now only catches AttributeError, as
675 documented, rather than returning the default value for all
676 exceptions (which could mask bugs in a __getattr__ hook, for
677 example).
678
Fred Drakecb7a6b52001-10-22 18:41:51 +0000679- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000680 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000681 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000682 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000683
Guido van Rossum1c486092001-10-19 02:05:35 +0000684- unicode(obj) now behaves more like str(obj), accepting arbitrary
685 objects, and calling a __unicode__ method if it exists.
686 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000687 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000688
Barry Warsawf6fb1712001-10-19 05:35:40 +0000689- isinstance() now allows any object as the first argument and a
690 class, a type or something with a __bases__ tuple attribute for the
691 second argument. The second argument may also be a tuple of a
692 class, type, or something with __bases__, in which case isinstance()
693 will return true if the first argument is an instance of any of the
694 things contained in the second argument tuple. E.g.
695
696 isinstance(x, (A, B))
697
698 returns true if x is an instance of A or B.
699
Guido van Rossum9074ef62001-10-16 21:34:49 +0000700Extension modules
701
702- thread.start_new_thread() now returns the thread ID (previously None).
703
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000704- binascii has now two quopri support functions, a2b_qp and b2a_qp.
705
Guido van Rossumc524d952001-10-19 01:31:59 +0000706- readline now supports setting the startup_hook and the
707 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000708
Guido van Rossumc524d952001-10-19 01:31:59 +0000709- os and posix supports chroot(), setgroups() and unsetenv() where
710 available. The stat(), fstat(), statvfs() and fstatvfs() functions
711 now return "pseudo-sequences" -- the various fields can now be
712 accessed as attributes (e.g. os.stat("/").st_mtime) but for
713 backwards compatibility they also behave as a fixed-length sequence.
714 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000715 attributes.
716
717- time: localtime(), gmtime() and strptime() now return a
718 pseudo-sequence similar to the os.stat() return value, with
719 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000720
Guido van Rossum9074ef62001-10-16 21:34:49 +0000721- Decompression objects in the zlib module now accept an optional
722 second parameter to decompress() that specifies the maximum amount
723 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000724
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000725- optional SSL support in the socket module now exports OpenSSL
726 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
727 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000728 automatically seed its PRNG. Also, the keyfile and certfile
729 arguments to socket.ssl() are now optional.
730
731- posixmodule (and by extension, the os module on POSIX platforms) now
732 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000733
Guido van Rossum9074ef62001-10-16 21:34:49 +0000734Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000735
Tim Peters7402f792001-10-02 03:53:41 +0000736- doctest now excludes functions and classes not defined by the module
737 being tested, thanks to Tim Hochberg.
738
Fred Drakecb7a6b52001-10-22 18:41:51 +0000739- HotShot, a new profiler implemented using a C-based callback, has
740 been added. This substantially reduces the overhead of profiling,
741 but it is still quite preliminary. Support modules and
742 documentation will be added in upcoming releases (before 2.2 final).
743
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000744- profile now produces correct output in situations where an exception
745 raised in Python is cleared by C code (e.g. hasattr()). This used
746 to cause wrong output, including spurious claims of recursive
747 functions and attribution of time spent to the wrong function.
748
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000749 The code and documentation for the derived OldProfile and HotProfile
750 profiling classes was removed. The code hasn't worked for years (if
751 you tried to use them, they raised exceptions). OldProfile
752 intended to reproduce the behavior of the profiler Python used more
753 than 7 years ago, and isn't interesting anymore. HotProfile intended
754 to provide a faster profiler (but producing less information), and
755 that's a worthy goal we intend to meet via a different approach (but
756 without losing information).
757
Tim Peterscce092d2001-10-09 05:31:56 +0000758- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000759 a much better system-specific calibration constant. The constant can
760 now be specified in an instance constructor, or as a Profile class or
761 instance variable, instead of by editing profile.py's source code.
762 Calibration must still be done manually (see the docs for the profile
763 module).
764
765 Note that Profile.calibrate() must be overriden by subclasses.
766 Improving the accuracy required exploiting detailed knowledge of
767 profiler internals; the earlier method abstracted away the details
768 and measured a simplified model instead, but consequently computed
769 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000770
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000771- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000772 which indicates whether output is intended for the header 'Q'
773 encoding.
774
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000775- The SocketServer.ThreadingMixIn class now closes the request after
776 finish_request() returns. (Not when it errors out though.)
777
Barry Warsawf6fb1712001-10-19 05:35:40 +0000778- The nntplib module's NNTP.body() method has grown a `file' argument
779 to allow saving the message body to a file.
780
781- The email package has added a class email.Parser.HeaderParser which
782 only parses headers and does not recurse into the message's body.
783 Also, the module/class MIMEAudio has been added for representing
784 audio data (contributed by Anthony Baxter).
785
786- ftplib should be able to handle files > 2GB.
787
788- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
789 ON, and OFF.
790
Fred Drakecb7a6b52001-10-22 18:41:51 +0000791- xml.dom.minidom NodeList objects now support the length attribute
792 and item() method as required by the DOM specifications.
793
Guido van Rossumed554f62001-10-02 23:15:37 +0000794Tools/Demos
795
796- Demo/dns was removed. It no longer serves any purpose; a package
797 derived from it is now maintained by Anthony Baxter, see
798 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000799
Barry Warsawf6fb1712001-10-19 05:35:40 +0000800- The freeze tool has been made more robust, and two new options have
801 been added: -X and -E.
802
Tim Petersabf925f2001-09-28 21:53:42 +0000803Build
804
Barry Warsawf6fb1712001-10-19 05:35:40 +0000805- configure will use CXX in LINKCC if CXX is used to build main() and
806 the system requires to link a C++ main using the C++ compiler.
807
Tim Petersabf925f2001-09-28 21:53:42 +0000808C API
809
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000810- The documentation for the tp_compare slot is updated to require that
811 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
812 not correct. This is not yet enforced but will be enforced in
813 Python 2.3; even later, we may use -2 to indicate errors and +2 for
814 "NotImplemented". Right now, -1 should be used for an error return.
815
Tim Petersd38b1c72001-09-30 05:09:37 +0000816- PyLong_AsLongLong() now accepts int (as well as long) arguments.
817 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
818 as long) arguments.
819
Guido van Rossum3c288632001-10-16 21:13:49 +0000820- PyThread_start_new_thread() now returns a long int giving the thread
821 ID, if one can be calculated; it returns -1 for error, 0 if no
822 thread ID is calculated (this is an incompatible change, but only
823 the thread module used this API). This code has only really been
824 tested on Linux and Windows; other platforms please beware (and
825 report any bugs or strange behavior).
826
Guido van Rossum1c486092001-10-19 02:05:35 +0000827- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
828 input.
829
Tim Petersabf925f2001-09-28 21:53:42 +0000830New platforms
831
832Tests
833
834Windows
835
Tim Peters04cf1d32001-10-09 22:39:40 +0000836- Installer: If you install IDLE, and don't disable file-extension
837 registration, a new "Edit with IDLE" context (right-click) menu entry
838 is created for .py and .pyw files.
839
Tim Peters1ce3cf72001-10-01 17:58:40 +0000840- The signal module now supports SIGBREAK on Windows, thanks to Steven
841 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
842 action remains to call Win32 ExitProcess(). This can be changed via
843 signal.signal(). For example:
844
845 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
846 # (SIGINT) behavior.
847 import signal
848 signal.signal(signal.SIGBREAK,
849 signal.default_int_handler)
850
851 try:
852 while 1:
853 pass
854 except KeyboardInterrupt:
855 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
856 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
857 # program without the possibility for any Python-level cleanup).
858 print "Clean exit"
859
Tim Petersabf925f2001-09-28 21:53:42 +0000860
Tim Petersb07352e2001-09-08 01:25:47 +0000861What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000862Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000863===========================
864
Guido van Rossum808eea72001-09-25 04:15:41 +0000865Type/class unification and new-style classes
866
867- pydoc and inspect are now aware of new-style classes;
868 e.g. help(list) at the interactive prompt now shows proper
869 documentation for all operations on list objects.
870
871- Applications using Jim Fulton's ExtensionClass module can now safely
872 be used with Python 2.2. In particular, Zope 2.4.1 now works with
873 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
874 examples also work again. It is hoped that Gtk and Boost also work
875 with 2.2a4 and beyond. (If you can confirm this, please write
876 webmaster@python.org; if there are still problems, please open a bug
877 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000878
Tim Peters66c1a522001-09-24 21:17:50 +0000879- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
880 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
881 in the constructed property object. fget, fset and fdel weren't
882 discoverable from Python in 2.2a3. __doc__ is new, and allows to
883 associate a docstring with a property.
884
Guido van Rossum808eea72001-09-25 04:15:41 +0000885- Comparison overloading is now more completely implemented. For
886 example, a str subclass instance can properly be compared to a str
887 instance, and it can properly overload comparison. Ditto for most
888 other built-in object types.
889
890- The repr() of new-style classes has changed; instead of <type
891 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
892 *except* for built-in types, which are still rendered as <type
893 'Foo'> (to avoid upsetting existing code that might parse or
894 otherwise rely on repr() of certain type objects).
895
896- The repr() of new-style objects is now always <Foo object at XXX>;
897 previously, it was sometimes <Foo instance at XXX>.
898
899- For new-style classes, what was previously called __getattr__ is now
900 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000901 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000902 one in classic classes is defined which is called only if regular
903 attribute access raises AttributeError; to catch *all* attribute
904 access, you can use __getattribute__ (for new-style classes). If
905 both are defined, __getattribute__ is called first, and if it raises
906 AttributeError, __getattr__ is called.
907
908- The __class__ attribute of new-style objects can be assigned to.
909 The new class must have the same C-level object layout as the old
910 class.
911
912- The builtin file type can be subclassed now. In the usual pattern,
913 "file" is the name of the builtin type, and file() is a new builtin
914 constructor, with the same signature as the builtin open() function.
915 file() is now the preferred way to open a file.
916
917- Previously, __new__ would only see sequential arguments passed to
918 the type in a constructor call; __init__ would see both sequential
919 and keyword arguments. This made no sense whatsoever any more, so
920 now both __new__ and __init__ see all arguments.
921
922- Previously, hash() applied to an instance of a subclass of str or
923 unicode always returned 0. This has been repaired.
924
925- Previously, an operation on an instance of a subclass of an
926 immutable type (int, long, float, complex, tuple, str, unicode),
927 where the subtype didn't override the operation (and so the
928 operation was handled by the builtin type), could return that
929 instance instead a value of the base type. For example, if s was of
930 a str sublass type, s[:] returned s as-is. Now it returns a str
931 with the same value as s.
932
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000933- Provisional support for pickling new-style objects has been added.
934
Guido van Rossum808eea72001-09-25 04:15:41 +0000935Core
936
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000937- file.writelines() now accepts any iterable object producing strings.
938
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000939- PyUnicode_FromEncodedObject() now works very much like
940 PyObject_Str(obj) in that it tries to use __str__/tp_str
941 on the object if the object is not a string or buffer. This
942 makes unicode() behave like str() when applied to non-string/buffer
943 objects.
944
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000945- PyFile_WriteObject now passes Unicode objects to the file's write
946 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000947 of a print statement must support Unicode objects, i.e. they must
948 at least convert them into ASCII strings.
949
Guido van Rossum624c8af2001-09-18 15:21:04 +0000950- Thread scheduling on Solaris should be improved; it is no longer
951 necessary to insert a small sleep at the start of a thread in order
952 to let other runnable threads be scheduled.
953
Tim Petersb07352e2001-09-08 01:25:47 +0000954Library
955
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000956- StringIO.StringIO instances and cStringIO.StringIO instances support
957 read character buffer compatible objects for their .write() methods.
958 These objects are converted to strings and then handled as such
959 by the instances.
960
Barry Warsaw2f600732001-09-24 04:28:10 +0000961- The "email" package has been added. This is basically a port of the
962 mimelib package <http://sf.net/projects/mimelib> with API changes
963 and some implementations updated to use iterators and generators.
964
Tim Peters8a9c2842001-09-22 21:30:22 +0000965- difflib.ndiff() and difflib.Differ.compare() are generators now. This
966 restores the ability of Tools/scripts/ndiff.py to start producing output
967 before the entire comparison is complete.
968
Barry Warsaw58b072d2001-09-22 04:44:21 +0000969- StringIO.StringIO instances and cStringIO.StringIO instances support
970 iteration just like file objects (i.e. their .readline() method is
971 called for each iteration until it returns an empty string).
972
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000973- The codecs module has grown four new helper APIs to access
974 builtin codecs: getencoder(), getdecoder(), getreader(),
975 getwriter().
976
Guido van Rossum624c8af2001-09-18 15:21:04 +0000977- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
978 simplifies writing XML RPC servers.
979
Barry Warsaw647d5e82001-09-28 17:01:02 +0000980- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000981 after interpretation of symbolic links. On non-Unix systems, this
982 is an alias for os.path.abspath().
983
Tim Peters16a77ad2001-09-08 04:00:12 +0000984- operator.indexOf() (PySequence_Index() in the C API) now works with any
985 iterable object.
986
Guido van Rossum624c8af2001-09-18 15:21:04 +0000987- smtplib now supports various authentication and security features of
988 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000989
Guido van Rossum624c8af2001-09-18 15:21:04 +0000990- hmac: a new module implementing keyed hashing for message
991 authentication.
992
993- mimetypes now recognizes more extensions and file types. At the
994 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000995
Guido van Rossum624c8af2001-09-18 15:21:04 +0000996- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000997 Python 2.2 bytecode generation. It has also been promoted from a
998 Tool to a standard library package. (Tools/compiler still exists as
999 a sample driver.)
1000
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001001Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001002
Tim Petersb07352e2001-09-08 01:25:47 +00001003Build
1004
Guido van Rossum624c8af2001-09-18 15:21:04 +00001005- Large file support (LFS) is now automatic when the platform supports
1006 it; no more manual configuration tweaks are needed. On Linux, at
1007 least, it's possible to have a system whose C library supports large
1008 files but whose kernel doesn't; in this case, large file support is
1009 still enabled but doesn't do you any good unless you upgrade your
1010 kernel or share your Python executable with another system whose
1011 kernel has large file support.
1012
1013- The configure script now supplies plausible defaults in a
1014 cross-compilation environment. This doesn't mean that the supplied
1015 values are always correct, or that cross-compilation now works
1016 flawlessly -- but it's a first step (and it shuts up most of
1017 autoconf's warnings about AC_TRY_RUN).
1018
1019- The Unix build is now a bit less chatty, courtesy of the parser
1020 generator. The build is completely silent (except for errors) when
1021 using "make -s", thanks to a -q option to setup.py.
1022
Tim Petersb07352e2001-09-08 01:25:47 +00001023C API
1024
Guido van Rossum624c8af2001-09-18 15:21:04 +00001025- The "structmember" API now supports some new flag bits to deny read
1026 and/or write access to attributes in restricted execution mode.
1027
Tim Petersb07352e2001-09-08 01:25:47 +00001028New platforms
1029
Guido van Rossum624c8af2001-09-18 15:21:04 +00001030- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1031 (http://familiar.handhelds.org).
1032
Tim Petersb07352e2001-09-08 01:25:47 +00001033Tests
1034
Tim Peters8a9c2842001-09-22 21:30:22 +00001035- The "classic" standard tests, which work by comparing stdout to
1036 an expected-output file under Lib/test/output/, no longer stop at
1037 the first mismatch. Instead the test is run to completion, and a
1038 variant of ndiff-style comparison is used to report all differences.
1039 This is much easier to understand than the previous style of reporting.
1040
1041- The unittest-based standard tests now use regrtest's test_main()
1042 convention, instead of running as a side-effect of merely being
1043 imported. This allows these tests to be run in more natural and
1044 flexible ways as unittests, outside the regrtest framework.
1045
1046- regrtest.py is much better integrated with unittest and doctest now,
1047 especially in regard to reporting errors.
1048
Tim Petersb07352e2001-09-08 01:25:47 +00001049Windows
1050
Guido van Rossum624c8af2001-09-18 15:21:04 +00001051- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001052 that support it (NTFS under Windows 2000). See "What's New in
1053 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001054
Tim Petersb07352e2001-09-08 01:25:47 +00001055
Tim Petersedc99312001-08-22 21:36:50 +00001056What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001057Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001058===========================
1059
1060Core
1061
Tim Peters9fffa3e2001-09-04 05:14:19 +00001062- Conversion of long to float now raises OverflowError if the long is too
1063 big to represent as a C double.
1064
Tim Peters32f453e2001-09-03 08:35:41 +00001065- The 3-argument builtin pow() no longer allows a third non-None argument
1066 if either of the first two arguments is a float, or if both are of
1067 integer types and the second argument is negative (in which latter case
1068 the arguments are converted to float, so this is really the same
1069 restriction).
1070
Tim Peters5d2b77c2001-09-03 05:47:38 +00001071- The builtin dir() now returns more information, and sometimes much
1072 more, generally naming all attributes of an object, and all attributes
1073 reachable from the object via its class, and from its class's base
1074 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1075 an empty list. In 2.2a3,
1076
1077 >>> dir([])
1078 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1079 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1080 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1081 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1082 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1083 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1084 'reverse', 'sort']
1085
1086 dir(module) continues to return only the module's attributes, though.
1087
Tim Petersbdee63f2001-09-02 03:40:59 +00001088- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001089 than raising OverflowError. This is a partial implementation of PEP
1090 237. You can use -Wdefault::OverflowWarning to enable a warning for
1091 this situation, and -Werror::OverflowWarning to revert to the old
1092 OverflowError exception.
1093
Guido van Rossum61c345f2001-09-04 03:26:15 +00001094- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001095 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001096 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1097 -Qold, meaning the / operator has its classic meaning and no
1098 warnings are issued. Using -Qwarn issues a run-time warning about
1099 all uses of classic division for int and long arguments; -Qwarnall
1100 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001101 (for use with fixdiv.py).
1102 [Note: the remainder of this paragraph (preserved below) became
1103 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1104 <obsolete>
1105 Using -Qnew is questionable; it turns on new division by default, but
1106 only in the __main__ module. You can usefully combine -Qwarn or
1107 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1108 warns about classic division everywhere else.
1109 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001110
Tim Petersbdee63f2001-09-02 03:40:59 +00001111- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001112 long, float, str, unicode, and tuple. (The types complex, list and
1113 dictionary can also be subclassed; this was introduced earlier.)
1114 Note that restrictions apply when subclassing immutable built-in
1115 types: you can only affect the value of the instance by overloading
1116 __new__. You can add mutable attributes, and the subclass instances
1117 will have a __dict__ attribute, but you cannot change the "value"
1118 (as implemented by the base class) of an immutable subclass instance
1119 once it is created.
1120
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001121- The dictionary constructor now takes an optional argument, a
1122 mapping-like object, and initializes the dictionary from its
1123 (key, value) pairs.
1124
Tim Petersbdee63f2001-09-02 03:40:59 +00001125- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001126 "cooperative super calls" in a multiple inheritance setting. For an
1127 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1128
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001129- A new built-in type, property, has been added. This enables the
1130 creation of "properties". These are attributes implemented by
1131 getter and setter functions (or only one of these for read-only or
1132 write-only attributes), without the need to override __getattr__.
1133 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001134
Tim Petersbdee63f2001-09-02 03:40:59 +00001135- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001136 liberalized, to allow leading zeroes. Examples of literals now
1137 legal that were SyntaxErrors before:
1138
1139 00.0 0e3 0100j 07.5 00000000000000000008.
1140
Tim Petersbdee63f2001-09-02 03:40:59 +00001141- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001142 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1143
Tim Petersedc99312001-08-22 21:36:50 +00001144Library
1145
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001146- telnetlib includes symbolic names for the options, and support for
1147 setting an option negotiation callback.
1148
Tim Petersa40c7932001-09-05 22:36:56 +00001149- The new C standard no longer requires that math libraries set errno to
1150 ERANGE on overflow. For platform libraries that exploit this new
1151 freedom, Python's overflow-checking was wholly broken. A new overflow-
1152 checking scheme attempts to repair that, but may not be reliable on all
1153 platforms (C doesn't seem to provide anything both useful and portable
1154 in this area anymore).
1155
Martin v. Löwis44f86962001-09-05 13:44:54 +00001156- Asynchronous timeout actions are available through the new class
1157 threading.Timer.
1158
Tim Peters78526162001-09-05 00:53:45 +00001159- math.log and math.log10 now return sensible results for even huge
1160 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1161
Tim Petersbdee63f2001-09-02 03:40:59 +00001162- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001163 currently held. See the docs for the imp module.
1164
Tim Petersbdee63f2001-09-02 03:40:59 +00001165- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001166 dumps containing ints written on platforms where Python ints are 8 bytes.
1167 When read on a box where Python ints are 4 bytes, such values are
1168 converted to Python longs.
1169
Tim Petersbdee63f2001-09-02 03:40:59 +00001170- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001171 code objects is no longer allowed. This plugs a security hole.
1172
Steve Purcell6091cd62001-09-06 16:05:17 +00001173- unittest.TestResult instances no longer store references to tracebacks
1174 generated by test failures. This prevents unexpected dangling references
1175 to objects that should be garbage collected between tests.
1176
Tim Petersedc99312001-08-22 21:36:50 +00001177Tools
1178
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001179- Tools/scripts/fixdiv.py has been added which can be used to fix
1180 division operators as per PEP 238.
1181
Tim Petersedc99312001-08-22 21:36:50 +00001182Build
1183
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001184- If you are an adventurous person using Mac OS X you may want to look at
1185 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1186 application, which can be used for experimenting with Carbon or Cocoa.
1187 Discussion of this on pythonmac-sig, please.
1188
Tim Peters7eea37e2001-09-04 22:08:56 +00001189C API
1190
1191- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001192
Tim Peters9fffa3e2001-09-04 05:14:19 +00001193- Note that PyLong_AsDouble can fail! This has always been true, but no
1194 callers checked for it. It's more likely to fail now, because overflow
1195 errors are properly detected now. The proper way to check:
1196
1197 double x = PyLong_AsDouble(some_long_object);
1198 if (x == -1.0 && PyErr_Occurred()) {
1199 /* The conversion failed. */
1200 }
1201
Tim Petersbdee63f2001-09-02 03:40:59 +00001202- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001203 compile but will not participate in GC. To upgrade an extension
1204 module:
1205
1206 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001207
Neil Schemenauer4042c692001-08-30 15:38:01 +00001208 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1209 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001210
Neil Schemenauer4042c692001-08-30 15:38:01 +00001211 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1212 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001213
Neil Schemenauer4042c692001-08-30 15:38:01 +00001214 - remove PyGC_HEAD_SIZE from object size calculations
1215
1216 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1217
Tim Petersbdee63f2001-09-02 03:40:59 +00001218- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001219 These can be used safely to construct string objects from a
1220 sprintf-style format string (similar to the format string supported
1221 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001222
Tim Petersedc99312001-08-22 21:36:50 +00001223New platforms
1224
Tim Petersb7da0902001-09-02 23:01:43 +00001225- Stephen Hansen contributed patches sufficient to get a clean compile
1226 under Borland C (Windows), but he reports problems running it and ran
1227 out of time to complete the port. Volunteers? Expect a MemoryError
1228 when importing the types module; this is probably shallow, and
1229 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001230
Tim Petersedc99312001-08-22 21:36:50 +00001231Tests
1232
1233Windows
1234
Tim Peters6e13a562001-09-06 00:32:15 +00001235- Large file support is now enabled on Win32 platforms as well as on
1236 Win64. This means that, for example, you can use f.tell() and f.seek()
1237 to manipulate files larger than 2 gigabytes (provided you have enough
1238 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001239 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1240 filesize limit, and large file support makes no difference there.
1241 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1242 NTFS has no practical limit on file size, and files of any size can be
1243 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001244
Tim Petersbdee63f2001-09-02 03:40:59 +00001245- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001246 points to command.com (patch from Brian Quinlan).
1247
Tim Petersedc99312001-08-22 21:36:50 +00001248
Tim Peters20f51a72001-07-21 02:31:40 +00001249What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001250Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001251===========================
1252
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001253Build
1254
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001255- Tim Peters developed a brand new Windows installer using Wise 8.1,
1256 generously donated to us by Wise Solutions.
1257
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001258- configure supports a new option --enable-unicode, with the values
1259 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1260 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001261
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001262- A new configure option --enable-framework builds a Mac OS X framework,
1263 which "make frameworkinstall" will install. This provides a starting
1264 point for more mac-like functionality, join pythonmac-sig@python.org
1265 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001266
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001267- The NeXT platform is no longer supported.
1268
1269- The `new' module is now statically linked.
1270
Tim Peters0afb6092001-08-15 06:06:44 +00001271Tools
1272
1273- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001274 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001275 the module docstring for details.
1276
Tim Peters20f51a72001-07-21 02:31:40 +00001277Tests
1278
Tim Peters5e824c32001-08-12 22:25:01 +00001279- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001280 platforms, allowing to give clearer test result output. regrtest
1281 also has optional --use/-u switch to run normally disabled tests
1282 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001283
Tim Peters20f51a72001-07-21 02:31:40 +00001284- Several new tests in the standard test suite, with special thanks to
1285 Nick Mathewson.
1286
1287Core
1288
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001289- The floor division operator // has been added as outlined in PEP
1290 238. The / operator still provides classic division (and will until
1291 Python 3.0) unless "from __future__ import division" is included, in
1292 which case the / operator will provide true division. The operator
1293 module provides truediv() and floordiv() functions. Augmented
1294 assignment variants are included, as are the equivalent overloadable
1295 methods and C API methods. See the PEP for a full discussion:
1296 <http://python.sf.net/peps/pep-0238.html>
1297
Tim Peters6cd6a822001-08-17 22:11:27 +00001298- Future statements are now effective in simulated interactive shells
1299 (like IDLE). This should "just work" by magic, but read Michael
1300 Hudson's "Future statements in simulated shells" PEP 264 for full
1301 details: <http://python.sf.net/peps/pep-0264.html>.
1302
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001303- The type/class unification (PEP 252-253) was integrated into the
1304 trunk and is not so tentative any more (the exact specification of
1305 some features is still tentative). A lot of work has done on fixing
1306 bugs and adding robustness and features (performance still has to
1307 come a long way).
1308
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001309- Warnings about a mismatch in the Python API during extension import
1310 now use the Python warning framework (which makes it possible to
1311 write filters for these warnings).
1312
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001313- A function's __dict__ (aka func_dict) will now always be a
1314 dictionary. It used to be possible to delete it or set it to None,
1315 but now both actions raise TypeErrors. It is still legal to set it
1316 to a dictionary object. Getting func.__dict__ before any attributes
1317 have been assigned now returns an empty dictionary instead of None.
1318
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001319- A new command line option, -E, was added which disables the use of
1320 all environment variables, or at least those that are specifically
1321 significant to Python. Usually those have a name starting with
1322 "PYTHON". This was used to fix a problem where the tests fail if
1323 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1324 older distribution.
1325
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001326Library
1327
Tim Peters5e824c32001-08-12 22:25:01 +00001328- New class Differ and new functions ndiff() and restore() in difflib.py.
1329 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001330 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001331
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001332- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1333 value using the minimal quoting required for the value; more
1334 reliable than using xml.sax.saxutils.escape() for attribute values.
1335
1336- Readline completion support for cmd.Cmd was added.
1337
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001338- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1339
1340- Added function threading.BoundedSemaphore()
1341
1342- Added Ka-Ping Yee's cgitb.py module.
1343
1344- The `new' module now exposes the CO_xxx flags.
1345
Martin v. Löwis560da622001-11-24 09:24:51 +00001346- The gc module offers the get_referents function.
1347
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001348New platforms
1349
1350C API
1351
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001352- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1353 which provide a cross-platform implementations for the
1354 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1355 the standard sprintf() and vsprintf() C lib APIs, these versions
1356 apply bounds checking on the used buffer which enhances protection
1357 against buffer overruns.
1358
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001359- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001360 and extensions using different Unicode widths is rendered next to
1361 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001362 will result in an ImportError. Unicode extensions writers must make
1363 sure to check the Unicode width compatibility in their extensions by
1364 using at least one of the mangled Unicode APIs in the extension.
1365
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001366- Two new flags METH_NOARGS and METH_O are available in method definition
1367 tables to simplify implementation of methods with no arguments and a
1368 single untyped argument. Calling such methods is more efficient than
1369 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1370 deprecated.
1371
Tim Petersc1731372001-08-04 08:12:36 +00001372Windows
1373
1374- "import module" now compiles module.pyw if it exists and nothing else
1375 relevant is found.
1376
Tim Peters20f51a72001-07-21 02:31:40 +00001377
Guido van Rossum55a78992001-07-17 17:22:32 +00001378What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001379Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001380===========================
1381
1382Core
Tim Petersa814db52001-05-14 07:05:58 +00001383
Tim Peters6d6c1a32001-08-02 04:15:00 +00001384- TENTATIVELY, a large amount of code implementing much of what's
1385 described in PEP 252 (Making Types Look More Like Classes) and PEP
1386 253 (Subtyping Built-in Types) was added. This will be released
1387 with Python 2.2a1. Documentation will be provided separately
1388 through http://www.python.org/2.2/. The purpose of releasing this
1389 with Python 2.2a1 is to test backwards compatibility. It is
1390 possible, though not likely, that a decision is made not to release
1391 this code as part of 2.2 final, if any serious backwards
1392 incompapatibilities are found during alpha testing that cannot be
1393 repaired.
1394
Guido van Rossum55a78992001-07-17 17:22:32 +00001395- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001396 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001397 more 'yield' statements. See PEP 255. Since this adds a new
1398 keyword to the language, this feature must be enabled by including a
1399 future statement: "from __future__ import generators" (see PEP 236).
1400 Generators will become a standard feature in a future release
1401 (probably 2.3). Without this future statement, 'yield' remains an
1402 ordinary identifier, but a warning is issued each time it is used.
1403 (These warnings currently don't conform to the warnings framework of
1404 PEP 230; we intend to fix this in 2.2a2.)
1405
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001406- The UTF-16 codec was modified to be more RFC compliant. It will now
1407 only remove BOM characters at the start of the string and then
1408 only if running in native mode (UTF-16-LE and -BE won't remove a
1409 leading BMO character).
1410
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001411- Strings now have a new method .decode() to complement the already
1412 existing .encode() method. These two methods provide direct access
1413 to the corresponding decoders and encoders of the registered codecs.
1414
1415 To enhance the usability of the .encode() method, the special
1416 casing of Unicode object return values was dropped (Unicode objects
1417 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001418
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001419 Both methods will now return whatever the codec in charge of the
1420 requested encoding returns as object, e.g. Unicode codecs will
1421 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1422 will return u"äöü"). This enables codec writer to create codecs
1423 for various simple to use conversions.
1424
1425 New codecs were added to demonstrate these new features (the .encode()
1426 and .decode() columns indicate the type of the returned objects):
1427
1428 Name | .encode() | .decode() | Description
1429 ----------------------------------------------------------------------
1430 uu | string | string | UU codec (e.g. for email)
1431 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001432 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001433 zlib | string | string | zlib compression
1434 hex | string | string | 2-byte hex codec
1435 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1436
Mark Hammond2a0af792001-05-14 03:09:36 +00001437- Some operating systems now support the concept of a default Unicode
1438 encoding for file system operations. Notably, Windows supports 'mbcs'
1439 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001440 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001441 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001442
1443 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001444 functions that return filenames (such as os.listdir()) to return Python
1445 string objects pre-encoded using the default file system encoding for
1446 the platform. As this encoding is likely to be different from Python's
1447 default encoding, converting this name to a Unicode object before passing
1448 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001449 would attempt to use its default encoding (generally ASCII) rather than
1450 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001451
Tim Petersa814db52001-05-14 07:05:58 +00001452 In general, this change simply removes surprises when working with
1453 Unicode and the file system, making these operations work as you expect,
1454 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001455 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001456
Tim Peters61dff2b2001-05-08 15:43:37 +00001457- Float (and complex) literals in source code were evaluated to full
1458 precision only when running from a .py file; the same code loaded from a
1459 .pyc (or .pyo) file could suffer numeric differences starting at about the
1460 12th significant decimal digit. For example, on a machine with IEEE-754
1461 floating arithmetic,
1462
1463 x = 9007199254740992.0
1464 print long(x)
1465
1466 printed 9007199254740992 if run directly from .py, but 9007199254740000
1467 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1468 str(float) instead of repr(float) when building code objects. marshal
1469 now uses repr(float) instead, which should reproduce floats to full
1470 machine precision (assuming the platform C float<->string I/O conversion
1471 functions are of good quality).
1472
1473 This may cause floating-point results to change in some cases, and
1474 usually for the better, but may also cause numerically unstable
1475 algorithms to break.
1476
Tim Peters2f228e72001-05-13 00:19:31 +00001477- The implementation of dicts suffers fewer collisions, which has speed
1478 benefits. However, the order in which dict entries appear in dict.keys(),
1479 dict.values() and dict.items() may differ from previous releases for a
1480 given dict. Nothing is defined about this order, so no program should
1481 rely on it. Nevertheless, it's easy to write test cases that rely on the
1482 order by accident, typically because of printing the str() or repr() of a
1483 dict to an "expected results" file. See Lib/test/test_support.py's new
1484 sortdict(dict) function for a simple way to display a dict in sorted
1485 order.
1486
Tim Peters7a3bfc32001-06-12 01:22:22 +00001487- Many other small changes to dicts were made, resulting in faster
1488 operation along the most common code paths.
1489
Guido van Rossum10315822001-05-01 20:54:30 +00001490- Dictionary objects now support the "in" operator: "x in dict" means
1491 the same as dict.has_key(x).
1492
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001493- The update() method of dictionaries now accepts generic mapping
1494 objects. Specifically the argument object must support the .keys()
1495 and __getitem__() methods. This allows you to say, for example,
1496 {}.update(UserDict())
1497
Guido van Rossum10315822001-05-01 20:54:30 +00001498- Iterators were added; this is a generalized way of providing values
1499 to a for loop. See PEP 234. There's a new built-in function iter()
1500 to return an iterator. There's a new protocol to get the next value
1501 from an iterator using the next() method (in Python) or the
1502 tp_iternext slot (in C). There's a new protocol to get iterators
1503 using the __iter__() method (in Python) or the tp_iter slot (in C).
1504 Iterating (i.e. a for loop) over a dictionary generates its keys.
1505 Iterating over a file generates its lines.
1506
Tim Petersf553f892001-05-01 20:45:31 +00001507- The following functions were generalized to work nicely with iterator
1508 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001509 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001510 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1511 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001512 join() method of strings
1513 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001514 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1515 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001516 right-hand side of assignment statements with multiple targets, such as
1517 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001518
Tim Petersd85e1022001-05-11 21:51:48 +00001519- Accessing module attributes is significantly faster (for example,
1520 random.random or os.path or yourPythonModule.yourAttribute).
1521
Tim Peterse63415e2001-05-08 04:38:29 +00001522- Comparing dictionary objects via == and != is faster, and now works even
1523 if the keys and values don't support comparisons other than ==.
1524
Tim Peters95bf9392001-05-10 08:32:44 +00001525- Comparing dictionaries in ways other than == and != is slower: there were
1526 insecurities in the dict comparison implementation that could cause Python
1527 to crash if the element comparison routines for the dict keys and/or
1528 values mutated the dicts. Making the code bulletproof slowed it down.
1529
Tim Peterseb28ef22001-06-02 05:27:19 +00001530- Collisions in dicts are resolved via a new approach, which can help
1531 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001532 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001533 faster now. Thanks to Christian Tismer for pointing out the cause and
1534 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001535
Tim Peters52e155e2001-06-16 05:42:57 +00001536- repr() is much faster for large containers (dict, list, tuple).
1537
1538
Tim Petersa814db52001-05-14 07:05:58 +00001539Library
1540
Fred Drake960fdf92001-07-20 18:38:26 +00001541- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1542 were added to the string module. These a locale-indenpendent
1543 constants, unlike letters, lowercase, and uppercase. These are now
1544 use in appropriate locations in the standard library.
1545
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001546- The flags used in dlopen calls can now be configured using
1547 sys.setdlopenflags and queried using sys.getdlopenflags.
1548
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001549- Fredrik Lundh's xmlrpclib is now a standard library module. This
1550 provides full client-side XML-RPC support. In addition,
1551 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1552 one asyncore-based). Thanks to Eric Raymond for the documentation.
1553
Guido van Rossum643d3912001-07-05 14:46:25 +00001554- The xrange() object is simplified: it no longer supports slicing,
1555 repetition, comparisons, efficient 'in' checking, the tolist()
1556 method, or the start, stop and step attributes. See PEP 260.
1557
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001558- A new function fnmatch.filter to filter lists of file names was added.
1559
Barry Warsawffd674d2001-05-22 16:00:10 +00001560- calendar.py uses month and day names based on the current locale.
1561
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001562- strop is now *really* obsolete (this was announced before with 1.6),
1563 and issues DeprecationWarning when used (except for the four items
1564 that are still imported into string.py).
1565
Tim Petersa814db52001-05-14 07:05:58 +00001566- Cookie.py now sorts key+value pairs by key in output strings.
1567
1568- pprint.isrecursive(object) didn't correctly identify recursive objects.
1569 Now it does.
1570
Tim Peters95b3f782001-05-14 18:39:41 +00001571- pprint functions now much faster for large containers (tuple, list, dict).
1572
Tim Peters7b9542a2001-06-10 23:40:19 +00001573- New 'q' and 'Q' format codes in the struct module, corresponding to C
1574 types "long long" and "unsigned long long" (on Windows, __int64). In
1575 native mode, these can be used only when the platform C compiler supports
1576 these types (when HAVE_LONG_LONG is #define'd by the Python config
1577 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001578 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1579 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001580
Guido van Rossum83213cc2001-06-12 16:48:52 +00001581- The site module installs a new built-in function 'help' that invokes
1582 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1583 it displays a message reminding the user to use 'help()' or
1584 'help(object)'.
1585
Tim Petersa814db52001-05-14 07:05:58 +00001586Tests
1587
1588- New test_mutants.py runs dict comparisons where the key and value
1589 comparison operators mutute the dicts randomly during comparison. This
1590 rapidly causes Python to crash under earlier releases (not for the faint
1591 of heart: it can also cause Win9x to freeze or reboot!).
1592
1593- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001594 pprint.isreadable() return sensible results. Also verifies that simple
1595 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001596
Tim Peters4324aa32001-05-28 22:30:08 +00001597C API
1598
1599- Removed the unused last_is_sticky argument from the internal
1600 _PyTuple_Resize(). If this affects you, you were cheating.
1601
1602
Guido van Rossum55a78992001-07-17 17:22:32 +00001603======================================================================
1604
1605
Guido van Rossumffe13be2001-04-16 18:46:45 +00001606What's New in Python 2.1 (final)?
1607=================================
1608
1609We only changed a few things since the last release candidate, all in
1610Python library code:
1611
1612- A bug in the locale module was fixed that affected locales which
1613 define no grouping for numeric formatting.
1614
1615- A few bugs in the weakref module's implementations of weak
1616 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1617 and the test suite was updated to check for these bugs.
1618
1619- An old bug in the os.path.walk() function (introduced in Python
1620 2.0!) was fixed: a non-existent file would cause an exception
1621 instead of being ignored.
1622
1623- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1624 PyChecker.
1625
1626
Guido van Rossum5b08f132001-04-16 02:05:23 +00001627What's New in Python 2.1c2?
1628===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001629
Guido van Rossum5b08f132001-04-16 02:05:23 +00001630A flurry of small changes, and one showstopper fixed in the nick of
1631time made it necessary to release another release candidate. The list
1632here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001633
Guido van Rossum5b08f132001-04-16 02:05:23 +00001634Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001635
Guido van Rossum5b08f132001-04-16 02:05:23 +00001636- Tim discovered a nasty bug in the dictionary code, caused by
1637 PyDict_Next() calling dict_resize(), and the GC code's use of
1638 PyDict_Next() violating an assumption in dict_items(). This was
1639 fixed with considerable amounts of band-aid, but the net effect is a
1640 saner and more robust implementation.
1641
1642- Made a bunch of symbols static that were accidentally global.
1643
1644Build and Ports
1645
1646- The setup.py script didn't check for a new enough version of zlib
1647 (1.1.3 is needed). Now it does.
1648
1649- Changed "make clean" target to also remove shared libraries.
1650
1651- Added a more general warning about the SGI Irix optimizer to README.
1652
1653Library
1654
1655- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1656 omitted the slash between host and file.html.
1657
1658- The mailbox module's _Mailbox class contained a completely broken
1659 and undocumented seek() method. Ripped it out.
1660
1661- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1662 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1663
1664- Fixed a few last-minute bugs in unittest.
1665
1666Extensions
1667
1668- Reverted the patch to the OpenSSL code in socketmodule.c to support
1669 RAND_status() and the EGD, and the subsequent patch that tried to
1670 fix it for pre-0.9.5 versions; the problem with the patch is that on
1671 some systems it issues a warning whenever socket is imported, and
1672 that's unacceptable.
1673
1674Tests
1675
1676- Fixed the pickle tests to work with "import test.test_pickle".
1677
1678- Tweaked test_locale.py to actually run the test Windows.
1679
1680- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1681 not "wb" (which is not a valid mode at all).
1682
1683- Fix pstats browser crashes. Import readline if it exists to make
1684 the user interface nicer.
1685
1686- Add "import thread" to the top of test modules that import the
1687 threading module (test_asynchat and test_threadedtempfile). This
1688 prevents test failures caused by a broken threading module resulting
1689 from a previously caught failed import.
1690
1691- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1692 needed on some platforms (e.g. Solaris 8) when the tests are run
1693 twice in succession.
1694
1695- Skip rather than fail test_sunaudiodev if no audio device is found.
1696
1697
1698What's New in Python 2.1c1?
1699===========================
1700
1701This list was significantly updated when 2.1c2 was released; the 2.1c1
1702release didn't mention most changes that were actually part of 2.1c1:
1703
1704Legal
1705
1706- Copyright was assigned to the Python Software Foundation (PSF) and a
1707 PSF license (very similar to the CNRI license) was added.
1708
1709- The CNRI copyright notice was updated to include 2001.
1710
1711Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001712
Guido van Rossumc9932722001-04-12 02:31:27 +00001713- After a public outcry, assignment to __debug__ is no longer illegal;
1714 instead, a warning is issued. It will become illegal in 2.2.
1715
Guido van Rossum5b08f132001-04-16 02:05:23 +00001716- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1717 "%#x" now always prepends "0x", even if the value is zero.
1718
1719- Fixed some nits in the bytecode compiler.
1720
1721- Fixed core dumps when calling certain kinds of non-functions.
1722
1723- Fixed various core dumps caused by reference count bugs.
1724
1725Build and Ports
1726
1727- Use INSTALL_SCRIPT to install script files.
1728
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001729- New port: SCO Unixware 7, by Billy G. Allie.
1730
Guido van Rossum5b08f132001-04-16 02:05:23 +00001731- Updated RISCOS port.
1732
1733- Updated BeOS port and notes.
1734
1735- Various other porting problems resolved.
1736
1737Library
1738
1739- The TERMIOS and SOCKET modules are now truly obsolete and
1740 unnecessary. Their symbols are incorporated in the termios and
1741 socket modules.
1742
1743- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1744 better tests for pickling.
1745
1746- threading: make Condition.wait() robust against KeyboardInterrupt.
1747
1748- zipfile: add support to zipfile to support opening an archive
1749 represented by an open file rather than a file name. Fix bug where
1750 the archive was not properly closed. Fixed a bug in this bugfix
1751 where flush() was called for a read-only file.
1752
1753- imputil: added an uninstall() method to the ImportManager.
1754
1755- Canvas: fixed bugs in lower() and tkraise() methods.
1756
1757- SocketServer: API change (added overridable close_request() method)
1758 so that the TCP server can explicitly close the request.
1759
1760- pstats: Eric Raymond added a simple interactive statistics browser,
1761 invoked when the module is run as a script.
1762
1763- locale: fixed a problem in format().
1764
1765- webbrowser: made it work when the BROWSER environment variable has a
1766 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1767 KDE 2. Fixed some other nits.
1768
1769- unittest: changes to allow using a different exception than
1770 AssertionError, and added a few more function aliases. Some other
1771 small changes.
1772
1773- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1774
1775- asynchat: fixed a critical bug in asynchat that slipped through the
1776 2.1b2 release. Fixed another rare bug.
1777
1778- Fix some unqualified except: clauses (always a bad code example).
1779
1780XML
1781
1782- pyexpat: new API get_version_string().
1783
1784- Fixed some minidom bugs.
1785
1786Extensions
1787
1788- Fixed a core dump in _weakref. Removed the weakref.mapping()
1789 function (it adds nothing to the API).
1790
1791- Rationalized the use of header files in the readline module, to make
1792 it compile (albeit with some warnings) with the very recent readline
1793 4.2, without breaking for earlier versions.
1794
1795- Hopefully fixed a buffering problem in linuxaudiodev.
1796
1797- Attempted a fix to make the OpenSSL support in the socket module
1798 work again with pre-0.9.5 versions of OpenSSL.
1799
1800Tests
1801
1802- Added a test case for asynchat and asyncore.
1803
1804- Removed coupling between tests where one test failing could break
1805 another.
1806
1807Tools
1808
1809- Ping added an interactive help browser to pydoc, fixed some nits
1810 in the rest of the pydoc code, and added some features to his
1811 inspect module.
1812
1813- An updated python-mode.el version 4.1 which integrates Ken
1814 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1815 much nicer in XEmacs and Emacs. When stepping through your program
1816 with pdb, in either the shell window or the *Python* window, the
1817 source file and line will be tracked by an arrow. Very cool!
1818
1819- IDLE: syntax warnings in interactive mode are changed into errors.
1820
1821- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001822 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001823
1824- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001825
Barry Warsaw11e89c72001-04-11 20:37:57 +00001826
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001827What's New in Python 2.1 beta 2?
1828================================
1829
Guido van Rossum053ae352001-03-22 14:17:21 +00001830(Unlisted are many fixed bugs, more documentation, etc.)
1831
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001832Core language, builtins, and interpreter
1833
Guido van Rossum053ae352001-03-22 14:17:21 +00001834- The nested scopes work (enabled by "from __future__ import
1835 nested_scopes") is completed; in particular, the future now extends
1836 into code executed through exec, eval() and execfile(), and into the
1837 interactive interpreter.
1838
1839- When calling a base class method (e.g. BaseClass.__init__(self)),
1840 this is now allowed even if self is not strictly spoken a class
1841 instance (e.g. when using metaclasses or the Don Beaudry hook).
1842
1843- Slice objects are now comparable but not hashable; this prevents
1844 dict[:] from being accepted but meaningless.
1845
1846- Complex division is now calculated using less braindead algorithms.
1847 This doesn't change semantics except it's more likely to give useful
1848 results in extreme cases. Complex repr() now uses full precision
1849 like float repr().
1850
1851- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1852
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001853- It is illegal to assign to the name __debug__, which is set when the
1854 interpreter starts. It is effectively a compile-time constant.
1855
1856- A warning will be issued if a global statement for a variable
1857 follows a use or assignment of that variable.
1858
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001859Standard library
1860
Guido van Rossum053ae352001-03-22 14:17:21 +00001861- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1862 inspired by JUnit), is now part of the standard library. You now
1863 have a choice of two testing frameworks: unittest requires you to
1864 write testcases as separate code, doctest gathers them from
1865 docstrings. Both approaches have their advantages and
1866 disadvantages.
1867
1868- A new module Tix was added, which wraps the Tix extension library
1869 for Tk. With that module, it is not necessary to statically link
1870 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1871 require" command. See Demo/tix/.
1872
1873- tzparse.py is now obsolete.
1874
1875- In gzip.py, the seek() and tell() methods are removed -- they were
1876 non-functional anyway, and it's better if callers can test for their
1877 existence with hasattr().
1878
1879Python/C API
1880
1881- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1882 that's already in the dictionary during a PyDict_Next() iteration.
1883 This used to fail occasionally when a dictionary resize operation
1884 could be triggered that would rehash all the keys. All other
1885 modifications to the dictionary are still off-limits during a
1886 PyDict_Next() iteration!
1887
1888- New extended APIs related to passing compiler variables around.
1889
1890- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1891 implement isinstance() and issubclass().
1892
1893- Py_BuildValue() now has a "D" conversion to create a Python complex
1894 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001895
Fred Drake4e262a92001-03-22 18:26:47 +00001896- Extensions types which support weak references must now set the
1897 field allocated for the weak reference machinery to NULL themselves;
1898 this is done to avoid the cost of checking each object for having a
1899 weakly referencable type in PyObject_INIT(), since most types are
1900 not weakly referencable.
1901
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001902- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1903 free variables and cell variables to and from the frame's f_locals.
1904
1905- Variants of several functions defined in pythonrun.h have been added
1906 to support the nested_scopes future statement. The variants all end
1907 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1908 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1909 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001910 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001911
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001912Distutils
1913
1914- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1915 into the release tree.
1916
Tim Peters0e57abf2001-05-02 07:39:38 +00001917- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001918 (an uninstaller, more customization of the installer's display)
1919
1920- from Jack Jansen: added Mac-specific code to generate a dialog for
1921 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001922 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001923 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001924
1925- added 'platforms' and 'keywords' to the set of metadata that can be
1926 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001927
1928- applied patches from Jason Tishler to make the compiler class work with
1929 Cygwin.
1930
1931
Tim Peters2fe289a2001-03-01 22:19:38 +00001932What's New in Python 2.1 beta 1?
1933================================
Tim Petersd66595f2001-02-04 03:09:53 +00001934
1935Core language, builtins, and interpreter
1936
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001937- Following an outcry from the community about the amount of code
1938 broken by the nested scopes feature introduced in 2.1a2, we decided
1939 to make this feature optional, and to wait until Python 2.2 (or at
1940 least 6 months) to make it standard. The option can be enabled on a
1941 per-module basis by adding "from __future__ import nested_scopes" at
1942 the beginning of a module (before any other statements, but after
1943 comments and an optional docstring). See PEP 236 (Back to the
1944 __future__) for a description of the __future__ statement. PEP 227
1945 (Statically Nested Scopes) has been updated to reflect this change,
1946 and to clarify the semantics in a number of endcases.
1947
1948- The nested scopes code, when enabled, has been hardened, and most
1949 bugs and memory leaks in it have been fixed.
1950
1951- Compile-time warnings are now generated for a number of conditions
1952 that will break or change in meaning when nested scopes are enabled:
1953
1954 - Using "from...import *" or "exec" without in-clause in a function
1955 scope that also defines a lambda or nested function with one or
1956 more free (non-local) variables. The presence of the import* or
1957 bare exec makes it impossible for the compiler to determine the
1958 exact set of local variables in the outer scope, which makes it
1959 impossible to determine the bindings for free variables in the
1960 inner scope. To avoid the warning about import *, change it into
1961 an import of explicitly name object, or move the import* statement
1962 to the global scope; to avoid the warning about bare exec, use
1963 exec...in... (a good idea anyway -- there's a possibility that
1964 bare exec will be deprecated in the future).
1965
1966 - Use of a global variable in a nested scope with the same name as a
1967 local variable in a surrounding scope. This will change in
1968 meaning with nested scopes: the name in the inner scope will
1969 reference the variable in the outer scope rather than the global
1970 of the same name. To avoid the warning, either rename the outer
1971 variable, or use a global statement in the inner function.
1972
Neil Schemenauera35c6882001-02-27 04:45:05 +00001973- An optional object allocator has been included. This allocator is
1974 optimized for Python objects and should be faster and use less memory
1975 than the standard system allocator. It is not enabled by default
1976 because of possible thread safety problems. The allocator is only
1977 protected by the Python interpreter lock and it is possible that some
1978 extension modules require a thread safe allocator. The object
1979 allocator can be enabled by providing the "--with-pymalloc" option to
1980 configure.
1981
Tim Petersd66595f2001-02-04 03:09:53 +00001982Standard library
1983
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001984- pyexpat now detects the expat version if expat.h defines it. A
1985 number of additional handlers are provided, which are only available
1986 since expat 1.95. In addition, the methods SetParamEntityParsing and
1987 GetInputContext of Parser objects are available with 1.95.x
1988 only. Parser objects now provide the ordered_attributes and
1989 specified_attributes attributes. A new module expat.model was added,
1990 which offers a number of additional constants if 1.95.x is used.
1991
1992- xml.dom offers the new functions registerDOMImplementation and
1993 getDOMImplementation.
1994
1995- xml.dom.minidom offers a toprettyxml method. A number of DOM
1996 conformance issues have been resolved. In particular, Element now
1997 has an hasAttributes method, and the handling of namespaces was
1998 improved.
1999
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002000- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2001 getting information about live Python code, and pydoc.py, a module
2002 for interactively converting docstrings to HTML or text.
2003 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002004 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002005 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2006 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002007
Tim Peters1eff7962001-03-01 02:31:33 +00002008- New library module difflib.py, primarily packaging the SequenceMatcher
2009 class at the heart of the popular ndiff.py file-comparison tool.
2010
2011- doctest.py (a framework for verifying Python code examples in docstrings)
2012 is now part of the std library.
2013
Tim Petersd66595f2001-02-04 03:09:53 +00002014Windows changes
2015
Guido van Rossume3955a82001-03-02 14:05:59 +00002016- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2017 small GUI that lets you browse the module docstrings using your
2018 default web browser.
2019
Tim Peters1eff7962001-03-01 02:31:33 +00002020- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2021 Platforms) is implemented. See
2022
2023 http://python.sourceforge.net/peps/pep-0235.html
2024
2025 for full details, especially the "Current Lower-Left Semantics" section.
2026 The new Windows import rules are simpler than before:
2027
2028 A. If the PYTHONCASEOK environment variable exists, same as
2029 before: silently accept the first case-insensitive match of any
2030 kind; raise ImportError if none found.
2031
2032 B. Else search sys.path for the first case-sensitive match; raise
2033 ImportError if none found.
2034
2035 The same rules have been implented on other platforms with case-
2036 insensitive but case-preserving filesystems too (including Cygwin, and
2037 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002038
Tim Peters25a9ce32001-02-19 07:06:36 +00002039- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2040 what it's supposed to do (and does do under NT and 2000) via direct
2041 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002042 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002043 all Win9x systems before.
2044
Tim Peters1eff7962001-03-01 02:31:33 +00002045- Build: Subproject _test (effectively) renamed to _testcapi.
2046
Tim Peters2fe289a2001-03-01 22:19:38 +00002047New platforms
2048
2049- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2050 Thanks to Steven Majewski!
2051
2052- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2053 Tishler!
2054
Guido van Rossum9089b272001-03-02 06:49:50 +00002055- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2056 Schwertberger! See RISCOS/README for more information -- it seems
2057 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002058 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002059
Tim Peters25a9ce32001-02-19 07:06:36 +00002060
Tim Petersd7b5e882001-01-25 03:36:26 +00002061What's New in Python 2.1 alpha 2?
2062=================================
Tim Peters40ead762001-01-27 05:35:26 +00002063
Tim Petersd7b5e882001-01-25 03:36:26 +00002064Core language, builtins, and interpreter
2065
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002066- Scopes nest. If a name is used in a function or class, but is not
2067 local, the definition in the nearest enclosing function scope will
2068 be used. One consequence of this change is that lambda statements
2069 could reference variables in the namespaces where the lambda is
2070 defined. In some unusual cases, this change will break code.
2071
2072 In all previous version of Python, names were resolved in exactly
2073 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002074 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002075 function A is defined within a function B, the names bound in B are
2076 not visible in A. The new rules make names bound in B visible in A,
2077 unless A contains a name binding that hides the binding in B.
2078
2079 Section 4.1 of the reference manual describes the new scoping rules
2080 in detail. The test script in Lib/test/test_scope.py demonstrates
2081 some of the effects of the change.
2082
2083 The new rules will cause existing code to break if it defines nested
2084 functions where an outer function has local variables with the same
2085 name as globals or builtins used by the inner function. Example:
2086
2087 def munge(str):
2088 def helper(x):
2089 return str(x)
2090 if type(str) != type(''):
2091 str = helper(str)
2092 return str.strip()
2093
2094 Under the old rules, the name str in helper() is bound to the
2095 builtin function str(). Under the new rules, it will be bound to
2096 the argument named str and an error will occur when helper() is
2097 called.
2098
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002099- The compiler will report a SyntaxError if "from ... import *" occurs
2100 in a function or class scope. The language reference has documented
2101 that this case is illegal, but the compiler never checked for it.
2102 The recent introduction of nested scope makes the meaning of this
2103 form of name binding ambiguous. In a future release, the compiler
2104 may allow this form when there is no possibility of ambiguity.
2105
Tim Peters40ead762001-01-27 05:35:26 +00002106- repr(string) is easier to read, now using hex escapes instead of octal,
2107 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2108
2109 >>> "\texample \r\n" + chr(0) + chr(255)
2110 '\texample \r\n\x00\xff' # in 2.1
2111 '\011example \015\012\000\377' # in 2.0
2112
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002113- Functions are now compared and hashed by identity, not by value, since
2114 the func_code attribute is writable.
2115
Fred Drakefb9d7122001-02-01 20:00:40 +00002116- Weak references (PEP 205) have been added. This involves a few
2117 changes in the core, an extension module (_weakref), and a Python
2118 module (weakref). The weakref module is the public interface. It
2119 includes support for "explicit" weak references, proxy objects, and
2120 mappings with weakly held values.
2121
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002122- A 'continue' statement can now appear in a try block within the body
2123 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002124 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002125
Tim Petersd7b5e882001-01-25 03:36:26 +00002126Standard library
2127
Barry Warsaw30dbd142001-01-31 22:14:01 +00002128- mailbox.py now has a new class, PortableUnixMailbox which is
2129 identical to UnixMailbox but uses a more portable scheme for
2130 determining From_ separators. Also, the constructors for all the
2131 classes in this module have a new optional `factory' argument, which
2132 is a callable used when new message classes must be instantiated by
2133 the next() method.
2134
Tim Petersd7b5e882001-01-25 03:36:26 +00002135- random.py is now self-contained, and offers all the functionality of
2136 the now-deprecated whrandom.py. See the docs for details. random.py
2137 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002138 and restoring the internal state of the generator; and jumpahead(n),
2139 for quickly forcing the internal state to be the same as if n calls to
2140 random() had been made. The latter is particularly useful for multi-
2141 threaded programs, creating one instance of the random.Random() class for
2142 each thread, then using .jumpahead() to force each instance to use a
2143 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002144
Tim Peters0de88fc2001-02-01 04:59:18 +00002145- random.py's seed() function is new. For bit-for-bit compatibility with
2146 prior releases, use the whseed function instead. The new seed function
2147 addresses two problems: (1) The old function couldn't produce more than
2148 about 2**24 distinct internal states; the new one about 2**45 (the best
2149 that can be done in the Wichmann-Hill generator). (2) The old function
2150 sometimes produced identical internal states when passed distinct
2151 integers, and there was no simple way to predict when that would happen;
2152 the new one guarantees to produce distinct internal states for all
2153 arguments in [0, 27814431486576L).
2154
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002155- The socket module now supports raw packets on Linux. The socket
2156 family is AF_PACKET.
2157
Tim Peters9ea17ac2001-02-02 05:57:15 +00002158- test_capi.py is a start at running tests of the Python C API. The tests
2159 are implemented by the new Modules/_testmodule.c.
2160
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002161- A new extension module, _symtable, provides provisional access to the
2162 internal symbol table used by the Python compiler. A higher-level
2163 interface will be added on top of _symtable in a future release.
2164
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002165- Removed the obsolete soundex module.
2166
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002167- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2168 the isSameNode method; NamedNodeMap the get method.
2169
2170- xml.sax.expatreader supports the lexical handler property; it
2171 generates comment, startCDATA, and endCDATA events.
2172
Tim Petersee826f82001-01-31 19:39:44 +00002173Windows changes
2174
2175- Build procedure: the zlib project is built in a different way that
2176 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002177 the zlib binary used. See PCbuild\readme.txt for details. Your old
2178 zlib-related directories can be deleted; you'll need to download fresh
2179 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002180
Tim Peters9ea17ac2001-02-02 05:57:15 +00002181- Build: New subproject _test for the benefit of test_capi.py (see above).
2182
Tim Petersb16c56f2001-02-02 21:24:51 +00002183- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2184 interface to some Python compiler internals).
2185
2186- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002187 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002188
Tim Petersa3a3a032000-11-30 05:22:44 +00002189What's New in Python 2.1 alpha 1?
2190=================================
2191
2192Core language, builtins, and interpreter
2193
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002194- There is a new Unicode companion to the PyObject_Str() API
2195 called PyObject_Unicode(). It behaves in the same way as the
2196 former, but assures that the returned value is an Unicode object
2197 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002198
Guido van Rossumf98eda02001-01-17 15:54:45 +00002199- The comparison operators support "rich comparison overloading" (PEP
2200 207). C extension types can provide a rich comparison function in
2201 the new tp_richcompare slot in the type object. The cmp() function
2202 and the C function PyObject_Compare() first try the new rich
2203 comparison operators before trying the old 3-way comparison. There
2204 is also a new C API PyObject_RichCompare() (which also falls back on
2205 the old 3-way comparison, but does not constrain the outcome of the
2206 rich comparison to a Boolean result).
2207
2208 The rich comparison function takes two objects (at least one of
2209 which is guaranteed to have the type that provided the function) and
2210 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2211 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2212 object, which may be NotImplemented (in which case the tp_compare
2213 slot function is used as a fallback, if defined).
2214
2215 Classes can overload individual comparison operators by defining one
2216 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002217 __ge__. There are no explicit "reflected argument" versions of
2218 these; instead, __lt__ and __gt__ are each other's reflection,
2219 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2220 reflection (similar at the C level). No other implications are
2221 made; in particular, Python does not assume that == is the Boolean
2222 inverse of !=, or that < is the Boolean inverse of >=. This makes
2223 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002224
2225 Classes or types that want to implement (in)equality tests but not
2226 the ordering operators (i.e. unordered types) should implement ==
2227 and !=, and raise an error for the ordering operators.
2228
Guido van Rossuma88479f2001-01-18 14:28:08 +00002229 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002230 Boolean; e.g. a matrix type might want to return a matrix of bits
2231 for A < B, giving elementwise comparisons. Such types should ensure
2232 that any interpretation of their value in a Boolean context raises
2233 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2234 at the C level) to always raise an exception.
2235
Guido van Rossuma88479f2001-01-18 14:28:08 +00002236- Complex numbers use rich comparisons to define == and != but raise
2237 an exception for <, <=, > and >=. Unfortunately, this also means
2238 that cmp() of two complex numbers raises an exception when the two
2239 numbers differ. Since it is not mathematically meaningful to compare
2240 complex numbers except for equality, I hope that this doesn't break
2241 too much code.
2242
Tim Peters3389f192001-02-18 08:48:49 +00002243- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002244 not defined by the language, other than that it's arbitrary but
2245 consistent (see the Reference Manual). An implementation detail changed
2246 in 2.1a1 such that None now compares less than any other object. Code
2247 relying on this new behavior (like code that relied on the previous
2248 behavior) does so at its own risk.
2249
Barry Warsaw573b5412001-01-15 20:43:18 +00002250- Functions and methods now support getting and setting arbitrarily
2251 named attributes (PEP 232). Functions have a new __dict__
2252 (a.k.a. func_dict) which hold the function attributes. Methods get
2253 and set attributes on their underlying im_func. It is a TypeError
2254 to set an attribute on a bound method.
2255
Guido van Rossum051e3352001-01-15 19:11:10 +00002256- The xrange() object implementation has been improved so that
2257 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2258 limitation that in this case len(xrange(sys.maxint)) can't be
2259 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2260 work fine as long as the index i doesn't actually reach 2**31.
2261 (Python uses regular ints for sequence and string indices; fixing
2262 that is much more work.)
2263
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002264- Two changes to from...import:
2265
Guido van Rossumba381232001-02-03 15:06:40 +00002266 1) "from M import X" now works even if (after loading module M)
2267 sys.modules['M'] is not a real module; it's basically a getattr()
2268 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002269
2270 2) "from M import *" now looks for M.__all__ to decide which names to
2271 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2272 filters out names starting with '_' as before. Whether or not
2273 __all__ exists, there's no restriction on the type of M.
2274
Guido van Rossumf61f1662001-01-10 20:13:55 +00002275- File objects have a new method, xreadlines(). This is the fastest
2276 way to iterate over all lines in a file:
2277
2278 for line in file.xreadlines():
2279 ...do something to line...
2280
2281 See the xreadlines module (mentioned below) for how to do this for
2282 other file-like objects.
2283
2284- Even if you don't use file.xreadlines(), you may expect a speedup on
2285 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002286 quite a bit in platform-specific ways: on systems (like Linux) that
2287 support flockfile(), getc_unlocked(), and funlockfile(), those are
2288 used by default. On systems (like Windows) without getc_unlocked(),
2289 a complicated (but still thread-safe) method using fgets() is used by
2290 default.
2291
Tim Petersd52269b2001-01-25 06:23:18 +00002292 You can force use of the fgets() method by #define'ing
2293 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002294 getc_unlocked()).
2295
Tim Petersd52269b2001-01-25 06:23:18 +00002296 You can force fgets() not to be used by #define'ing
2297 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002298 test_bufio.py fails -- and let us know if it does!).
2299
2300- In addition, the fileinput module, while still slower than the other
2301 methods on most platforms, has been sped up too, by using
2302 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002303
2304- Support for run-time warnings has been added, including a new
2305 command line option (-W) to specify the disposition of warnings.
2306 See the description of the warnings module below.
2307
2308- Extensive changes have been made to the coercion code. This mostly
2309 affects extension modules (which can now implement mixed-type
2310 numerical operators without having to use coercion), but
2311 occasionally, in boundary cases the coercion semantics have changed
2312 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002313 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002314 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002315 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002316
Guido van Rossumf98eda02001-01-17 15:54:45 +00002317- In connection with the coercion changes, a new built-in singleton
2318 object, NotImplemented is defined. This can be returned for
2319 operations that wish to indicate they are not implemented for a
2320 particular combination of arguments. From C, this is
2321 Py_NotImplemented.
2322
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002323- The interpreter accepts now bytecode files on the command line even
2324 if they do not have a .pyc or .pyo extension. On Linux, after executing
2325
Martin v. Löwise214baa2001-02-04 22:37:56 +00002326import imp,sys,string
2327magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2328reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2329open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002330
2331 any byte code file can be used as an executable (i.e. as an argument
2332 to execve(2)).
2333
Tim Peters9940b802000-12-01 07:59:35 +00002334- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002335 character. In 1.6 and earlier, they never produced a sign,
2336 and raised an error if the value of the long was too large
2337 to fit in a Python int. In 2.0, they produced a sign if and
2338 only if too large to fit in an int. This was inconsistent
2339 across platforms (because the size of an int varies across
2340 platforms), and inconsistent with hex() and oct(). Example:
2341
2342 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002343 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002344 'ffffffbe' # in 2.0 and before, on 32-bit machines
2345 >>> hex(-0x42L)
2346 '-0x42L' # in all versions of Python
2347
Tim Peters9940b802000-12-01 07:59:35 +00002348 The behavior of %d formats for negative Python longs remains
2349 the same as in 2.0 (although in 1.6 and before, they raised
2350 an error if the long didn't fit in a Python int).
2351
2352 %u formats don't make sense for Python longs, but are allowed
2353 and treated the same as %d in 2.1. In 2.0, a negative long
2354 formatted via %u produced a sign if and only if too large to
2355 fit in an int. In 1.6 and earlier, a negative long formatted
2356 via %u raised an error if it was too big to fit in an int.
2357
Guido van Rossum3661d392000-12-12 22:10:31 +00002358- Dictionary objects have an odd new method, popitem(). This removes
2359 an arbitrary item from the dictionary and returns it (in the form of
2360 a (key, value) pair). This can be useful for algorithms that use a
2361 dictionary as a bag of "to do" items and repeatedly need to pick one
2362 item. Such algorithms normally end up running in quadratic time;
2363 using popitem() they can usually be made to run in linear time.
2364
Tim Peters36cdad12000-12-29 02:06:45 +00002365Standard library
2366
Thomas Woutersfe385252001-01-19 23:16:56 +00002367- In the time module, the time argument to the functions strftime,
2368 localtime, gmtime, asctime and ctime is now optional, defaulting to
2369 the current time (in the local timezone).
2370
Guido van Rossumda91f222001-01-15 16:36:08 +00002371- The ftplib module now defaults to passive mode, which is deemed a
2372 more useful default given that clients are often inside firewalls
2373 these days. Note that this could break if ftplib is used to connect
2374 to a *server* that is inside a firewall, from outside; this is
2375 expected to be a very rare situation. To fix that, you can call
2376 ftp.set_pasv(0).
2377
Martin v. Löwis10a27872001-01-13 09:54:41 +00002378- The module site now treats .pth files not only for path configuration,
2379 but also supports extensions to the initialization code: Lines starting
2380 with import are executed.
2381
Guido van Rossumf61f1662001-01-10 20:13:55 +00002382- There's a new module, warnings, which implements a mechanism for
2383 issuing and filtering warnings. There are some new built-in
2384 exceptions that serve as warning categories, and a new command line
2385 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2386 turns warnings into errors). warnings.warn(message[, category])
2387 issues a warning message; this can also be called from C as
2388 PyErr_Warn(category, message).
2389
2390- A new module xreadlines was added. This exports a single factory
2391 function, xreadlines(). The intention is that this code is the
2392 absolutely fastest way to iterate over all lines in an open
2393 file(-like) object:
2394
2395 import xreadlines
2396 for line in xreadlines.xreadlines(file):
2397 ...do something to line...
2398
2399 This is equivalent to the previous the speed record holder using
2400 file.readlines(sizehint). Note that if file is a real file object
2401 (as opposed to a file-like object), this is equivalent:
2402
2403 for line in file.xreadlines():
2404 ...do something to line...
2405
Tim Peters36cdad12000-12-29 02:06:45 +00002406- The bisect module has new functions bisect_left, insort_left,
2407 bisect_right and insort_right. The old names bisect and insort
2408 are now aliases for bisect_right and insort_right. XXX_right
2409 and XXX_left methods differ in what happens when the new element
2410 compares equal to one or more elements already in the list: the
2411 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002412 right. Code that doesn't care where equal elements end up should
2413 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002414
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002415- The new curses.panel module wraps the panel library that forms part
2416 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2417
Guido van Rossumf61f1662001-01-10 20:13:55 +00002418- The SocketServer module now sets the allow_reuse_address flag by
2419 default in the TCPServer class.
2420
2421- A new function, sys._getframe(), returns the stack frame pointer of
2422 the caller. This is intended only as a building block for
2423 higher-level mechanisms such as string interpolation.
2424
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002425- The pyexpat module supports a number of new handlers, which are
2426 available only in expat 1.2. If invocation of a callback fails, it
2427 will report an additional frame in the traceback. Parser objects
2428 participate now in garbage collection. If expat reports an unknown
2429 encoding, pyexpat will try to use a Python codec; that works only
2430 for single-byte charsets. The parser type objects is exposed as
2431 XMLParserObject.
2432
2433- xml.dom now offers standard definitions for symbolic node type and
2434 exception code constants, and a hierarchy of DOM exceptions. minidom
2435 was adjusted to use them.
2436
2437- The conformance of xml.dom.minidom to the DOM specification was
2438 improved. It detects a number of additional error cases; the
2439 previous/next relationship works even when the tree is modified;
2440 Node supports the normalize() method; NamedNodeMap, DocumentType and
2441 DOMImplementation classes were added; Element supports the
2442 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2443 method.
2444
Guido van Rossumf61f1662001-01-10 20:13:55 +00002445Build issues
2446
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002447- For Unix (and Unix-compatible) builds, configuration and building of
2448 extension modules is now greatly automated. Rather than having to
2449 edit the Modules/Setup file to indicate which modules should be
2450 built and where their include files and libraries are, a
2451 distutils-based setup.py script now takes care of building most
2452 extension modules. All extension modules built this way are built
2453 as shared libraries. Only a few modules that must be linked
2454 statically are still listed in the Setup file; you won't need to
2455 edit their configuration.
2456
2457- Python should now build out of the box on Cygwin. If it doesn't,
2458 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002459
2460- Python now always uses its own (renamed) implementation of getopt()
2461 -- there's too much variation among C library getopt()
2462 implementations.
2463
2464- C++ compilers are better supported; the CXX macro is always set to a
2465 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002466
Tim Petersd92dfe02000-12-12 01:18:41 +00002467Windows changes
2468
2469- select module: By default under Windows, a select() call
2470 can specify no more than 64 sockets. Python now boosts
2471 this Microsoft default to 512. If you need even more than
2472 that, see the MS docs (you'll need to #define FD_SETSIZE
2473 and recompile Python from source).
2474
Guido van Rossumf61f1662001-01-10 20:13:55 +00002475- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2476 subdirectory is no more!
2477
Tim Petersa3a3a032000-11-30 05:22:44 +00002478
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002479What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002480=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002481
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002482Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002483changes are in the file HISTORY. If you are making the jump directly
2484from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2485HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002486
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002487Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2488the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2489http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002490
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002491--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002492
2493======================================================================
2494
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002495What's new in 2.0 (since release candidate 1)?
2496==============================================
2497
2498Standard library
2499
2500- The copy_reg module was modified to clarify its intended use: to
2501 register pickle support for extension types, not for classes.
2502 pickle() will raise a TypeError if it is passed a class.
2503
2504- Fixed a bug in gettext's "normalize and expand" code that prevented
2505 it from finding an existing .mo file.
2506
2507- Restored support for HTTP/0.9 servers in httplib.
2508
Tim Peters989b7b92000-10-16 20:24:53 +00002509- The math module was changed to stop raising OverflowError in case of
2510 underflow, and return 0 instead in underflow cases. Whether Python
2511 used to raise OverflowError in case of underflow was platform-
2512 dependent (it did when the platform math library set errno to ERANGE
2513 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002514
2515- Fixed a bug in StringIO that occurred when the file position was not
2516 at the end of the file and write() was called with enough data to
2517 extend past the end of the file.
2518
2519- Fixed a bug that caused Tkinter error messages to get lost on
2520 Windows. The bug was fixed by replacing direct use of
2521 interp->result with Tcl_GetStringResult(interp).
2522
2523- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2524 redirect response.
2525
2526- Several changes were made to distutils: Some debugging code was
2527 removed from util. Fixed the installer used when an external zip
2528 program (like WinZip) is not found; the source code for this
2529 installer is in Misc/distutils. check_lib() was modified to behave
2530 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2531 test for whether installed modules are on sys.path was changed to
2532 use both normcase() and normpath().
2533
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002534- Several minor bugs were fixed in the xml package (the minidom,
2535 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002536
2537- The regression test driver (regrtest.py) behavior when invoked with
2538 -l changed: It now reports a count of objects that are recognized as
2539 garbage but not freed by the garbage collector.
2540
Tim Peters989b7b92000-10-16 20:24:53 +00002541- The regression test for the math module was changed to test
2542 exceptional behavior when the test is run in verbose mode. Python
2543 cannot yet guarantee consistent exception behavior across platforms,
2544 so the exception part of test_math is run only in verbose mode, and
2545 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002546
2547Internals
2548
2549- PyOS_CheckStack() has been disabled on Win64, where it caused
2550 test_sre to fail.
2551
2552Build issues
2553
2554- Changed compiler flags, so that gcc is always invoked with -Wall and
2555 -Wstrict-prototypes. Users compiling Python with GCC should see
2556 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002557 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002558 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002559
Tim Petersa3a3a032000-11-30 05:22:44 +00002560- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002561
2562Tools and other miscellany
2563
2564- The compiler in Tools/compiler was updated to support the new
2565 language features introduced in 2.0: extended print statement, list
2566 comprehensions, and augmented assignments. The new compiler should
2567 also be backwards compatible with Python 1.5.2; the compiler will
2568 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002569 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002570
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002571What's new in 2.0 release candidate 1 (since beta 2)?
2572=====================================================
2573
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002574What is release candidate 1?
2575
2576We believe that release candidate 1 will fix all known bugs that we
2577intend to fix for the 2.0 final release. This release should be a bit
2578more stable than the previous betas. We would like to see even more
2579widespread testing before the final release, so we are producing this
2580release candidate. The final release will be exactly the same unless
2581any show-stopping (or brown bag) bugs are found by testers of the
2582release candidate.
2583
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002584All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002585to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002586
2587Core language, builtins, and interpreter
2588
2589- A bug that caused crashes when __coerce__ was used with augmented
2590 assignment, e.g. +=, was fixed.
2591
2592- Raise ZeroDivisionError when raising zero to a negative number,
2593 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2594 power operator and the result of math.pow(0.0, -2.0) will vary by
2595 platform. On Linux, it raises a ValueError.
2596
2597- A bug in Unicode string interpolation was fixed that occasionally
2598 caused errors with formats including "%%". For example, the
2599 following expression "%% %s" % u"abc" no longer raises a TypeError.
2600
2601- Compilation of deeply nested expressions raises MemoryError instead
2602 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2603
2604- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2605 rendering them useless. They are now written in binary mode again.
2606
2607Standard library
2608
2609- Keyword arguments are now accepted for most pattern and match object
2610 methods in SRE, the standard regular expression engine.
2611
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002612- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002613 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002614
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002615- Several bugs in the Unicode handling and error handling in _tkinter
2616 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002617
2618- Fix memory management errors in Merge() and Tkapp_Call() routines.
2619
2620- Several changes were made to cStringIO to make it compatible with
2621 the file-like object interface and with StringIO. If operations are
2622 performed on a closed object, an exception is raised. The truncate
2623 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002624 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002625
2626- There were many changes made to the linuxaudiodev module and its
2627 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002628 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002629
2630 Note that this module is named poorly, because it should work
2631 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002632 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002633
2634 The module now raises exceptions when errors occur instead of
2635 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2636 audio) and defines a getptr() method that calls the
2637 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2638
2639- The library_version attribute, introduced in an earlier beta, was
2640 removed because it can not be supported with early versions of the C
2641 readline library, which provides no way to determine the version at
2642 compile-time.
2643
2644- The binascii module is now enabled on Win64.
2645
Tim Peters46446d62000-10-09 21:19:31 +00002646- tokenize.py no longer suffers "recursion depth" errors when parsing
2647 programs with very long string literals.
2648
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002649Internals
2650
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002651- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002652 which is called when the interpreter starts up to determine where
2653 the standard library is installed. These vulnerabilities affect all
2654 previous versions of Python and can be exploited by setting very
2655 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2656 setuid Python script, although use of the wrapper in
2657 Misc/setuid-prog.c will eliminate the vulnerability.
2658
2659- Fixed garbage collection bugs in instance creation that were
2660 triggered when errors occurred during initialization. The solution,
2661 applied in cPickle and in PyInstance_New(), is to call
2662 PyObject_GC_Init() after the initialization of the object's
2663 container attributes is complete.
2664
2665- pyexpat adds definitions of PyModule_AddStringConstant and
2666 PyModule_AddObject if the Python version is less than 2.0, which
2667 provides compatibility with PyXML on Python 1.5.2.
2668
2669- If the platform has a bogus definition for LONG_BIT (the number of
2670 bits in a long), an error will be reported at compile time.
2671
2672- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2673 collection crashes and possibly other, unreported crashes.
2674
2675- Fixed a memory leak in _PyUnicode_Fini().
2676
2677Build issues
2678
2679- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002680 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002681 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002682
2683- The mmap.PAGESIZE constant is now initialized using sysconf when
2684 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2685
2686- The md5 file should now compile on all platforms.
2687
2688- The select module now compiles on platforms that do not define
2689 POLLRDNORM and related constants.
2690
2691- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002692 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002693
Jeremy Hylton10921202000-10-09 18:34:12 +00002694- BeOS: A number of changes were made to the build and installation
2695 process. ar-fake now operates on a directory of object files.
2696 dl_export.h is gone, and its macros now appear on the mwcc command
2697 line during build on PPC BeOS.
2698
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002699- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002700 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002701
2702- Cygwin: Support for shared libraries, Tkinter, and sockets.
2703
2704- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2705
2706Tools and other miscellany
2707
2708- Removed debugging prints from main used with freeze.
2709
Tim Peters46446d62000-10-09 21:19:31 +00002710- IDLE auto-indent no longer crashes when it encounters Unicode
2711 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002712
2713What's new in 2.0 beta 2 (since beta 1)?
2714========================================
2715
2716Core language, builtins, and interpreter
2717
Tim Peters482c0212000-09-26 06:33:09 +00002718- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002719 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002720
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002721- Add -h and -V command line options to print the usage message and
2722 Python version number and exit immediately.
2723
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002724- eval() and exec accept Unicode objects as code parameters.
2725
2726- getattr() and setattr() now also accept Unicode objects for the
2727 attribute name, which are converted to strings using the default
2728 encoding before lookup.
2729
2730- Multiplication on string and Unicode now does proper bounds
2731 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2732 string is too long."
2733
2734- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002735 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002736
Jeremy Hylton1b618592000-09-26 05:32:36 +00002737
2738Standard library and extensions
2739
Guido van Rossum5b08f132001-04-16 02:05:23 +00002740- socket module: the OpenSSL code now adds support for RAND_status()
2741 and EGD (Entropy Gathering Device).
2742
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002743- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002744 argument checking; it still takes no arguments.
2745
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002746- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002747
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002748- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002749
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002750- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002751
2752- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002753 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002754
2755- copy: Copy Unicode objects atomically.
2756
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002757- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002758
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002759- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002760
Fred Drake67233bc2000-09-26 16:40:27 +00002761- dbm: Add get() and setdefault() methods to dbm object. Add constant
2762 `library' to module that names the library used. Added doc strings
2763 and method names to error messages. Uses configure to determine
2764 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2765 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002766
2767- distutils: Update to version 0.9.3.
2768
2769- dl: Add several dl.RTLD_ constants.
2770
2771- fpectl: Now supported on FreeBSD.
2772
2773- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2774 found by the collector will be saved in gc.garbage. This is useful
2775 for debugging a program that creates reference cycles.
2776
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002777- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002778 of HTTP class. Do not close socket on zero-length response. Do not
2779 crash when server sends invalid content-length header.
2780
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002781- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002782
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002783- marshal: When reading a short, sign-extend on platforms where shorts
2784 are bigger than 16 bits. When reading a long, repair the unportable
2785 sign extension that was being done for 64-bit machines. (It assumed
2786 that signed right shift sign-extends.)
2787
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002788- operator: Add contains(), invert(), __invert__() as aliases for
2789 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002790
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002791- os: Add support for popen2() and popen3() on all platforms where
2792 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002793
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002794- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002795 clicking on a file in Explorer (or passing the file name to the
2796 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002797
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002798- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002799 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002800
2801- pickle: Now raises ValueError when an invalid pickle that contains
2802 a non-string repr where a string repr was expected. This behavior
2803 matches cPickle.
2804
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002805- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002806
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002807- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002808
2809- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002810 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002811 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002812
2813- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002814 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002815
2816- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002817 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002818 few cycles during startup since the first call to
2819 setdefaultencoding() will initialize the codec registry and the
2820 encodings package.
2821
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002822- socket: Support for size hint in readlines() method of object returned
2823 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002824
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002825- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002826 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002827 is followed by whitespace.
2828
Tim Petersa3a3a032000-11-30 05:22:44 +00002829- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002830
2831- struct: Check ranges for bytes and shorts.
2832
2833- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002834 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002835
2836- Tkinter: Image objects are now guaranteed to have unique ids. Set
2837 event.delta to zero if Tk version doesn't support mousewheel.
2838 Removed some debugging prints.
2839
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002840- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841
Fred Drake67233bc2000-09-26 16:40:27 +00002842- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002843 which works around a bug in Norton AntiVirus 2000 that leads directly
2844 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002845
2846- xml: New version detection code allows PyXML to override standard
2847 XML package if PyXML version is greater than 0.6.1.
2848
Fred Drake64bb3802000-09-26 16:21:35 +00002849- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2850 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2851 tree only for nodes which are sufficiently interesting to a specific
2852 application. Does not provide the HTML-specific extensions. Still
2853 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002854
Fred Drake64bb3802000-09-26 16:21:35 +00002855- xml.sax: SAX 2 support for Python, including all the handler
2856 interfaces needed to process XML 1.0 compliant XML. Some
2857 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002858
Fred Drake64bb3802000-09-26 16:21:35 +00002859- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2860 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002861
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002862
Jeremy Hylton1b618592000-09-26 05:32:36 +00002863C API
2864
2865- Add three new convenience functions for module initialization --
2866 PyModule_AddObject(), PyModule_AddIntConstant(), and
2867 PyModule_AddStringConstant().
2868
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002869- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002870 removed and add #error to Python.h if NULL isn't defined after
2871 #include of stdio.h.
2872
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002873- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002874 backwards compatibility (at the source level) with old extensions.
2875
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002876- A wrapper API was added for signal() and sigaction(). Instead of
2877 either function, always use PyOS_getsig() to get a signal handler
2878 and PyOS_setsig() to set one. A new convenience typedef
2879 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002880
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002881- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002882 internal data buffer and size of a string object -- or the default
2883 encoded version of a Unicode object.
2884
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002885- PyString_Size() and PyString_AsString() accept Unicode objects.
2886
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002887- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002888 exists). INT_MAX and LONG_MAX will always be defined, even if
2889 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002890
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002891- PyFloat_FromString takes a second argument, pend, that was
2892 effectively useless. It is now officially useless but preserved for
2893 backwards compatibility. If the pend argument is not NULL, *pend is
2894 set to NULL.
2895
2896- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2897 for the attribute name. See note on getattr() above.
2898
2899- A few bug fixes to argument processing for Unicode.
2900 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2901 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2902 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002903 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002904
2905- Py_BuildValue accepts B format (for bgen-generated code).
2906
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002907
Jeremy Hylton1b618592000-09-26 05:32:36 +00002908Internals
2909
2910- On Unix, fix code for finding Python installation directory so that
2911 it works when argv[0] is a relative path.
2912
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002913- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002914 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002915 rather than by generating a copy of the object.
2916
Tim Peters482c0212000-09-26 06:33:09 +00002917- Several of the internal Unicode tables are much smaller now, and
2918 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002919
Jeremy Hylton97693b02000-09-26 17:42:51 +00002920- In the garbage collector: Fixed bug in collection of tuples. Fixed
2921 bug that caused some instances to be removed from the container set
2922 while they were still live. Fixed parsing in gc.set_debug() for
2923 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002924
2925- Fixed refcount problem in instance deallocation that only occurred
2926 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2927
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002928- On Windows, getpythonregpath is now protected against null data in
2929 registry key.
2930
2931- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002932 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002933
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002934
Jeremy Hylton1b618592000-09-26 05:32:36 +00002935Build and platform-specific issues
2936
2937- Better support of GNU Pth via --with-pth configure option.
2938
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002939- Python/C API now properly exposed to dynamically-loaded extension
2940 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002941
2942- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2943 Don't define MS_SYNC to be zero when it is undefined. Added missing
2944 prototypes in posixmodule.c.
2945
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002946- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002947 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002948
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002949- Fix largefile support on older NetBSD systems and OpenBSD by adding
2950 define for TELL64.
2951
2952
2953Tools and other miscellany
2954
2955- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2956
2957- freeze: The modulefinder now works with 2.0 opcodes.
2958
Tim Petersa3a3a032000-11-30 05:22:44 +00002959- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002960 Move hackery of sys.argv until after the Tk instance has been
2961 created, which allows the application-specific Tkinter
2962 initialization to be executed if present; also pass an explicit
2963 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002964
Jeremy Hylton1b618592000-09-26 05:32:36 +00002965
2966What's new in 2.0 beta 1?
2967=========================
2968
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002969Source Incompatibilities
2970------------------------
2971
2972None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2973such as single-argument append(), connect() and bind(), and changes to
2974str(long) and repr(float).
2975
2976
2977Binary Incompatibilities
2978------------------------
2979
2980- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2981with Python 2.0; these extensions will have to be rebuilt for Python
29822.0.
2983
2984- On Windows, attempting to import a third party extension built for
2985Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2986can do about this. Check your PYTHONPATH environment variable!
2987
2988- Python bytecode files (*.pyc and *.pyo) are not compatible between
2989releases.
2990
2991
2992Overview of Changes Since 1.6
2993-----------------------------
2994
2995There are many new modules (including brand new XML support through
2996the xml package, and i18n support through the gettext module); a list
2997of all new modules is included below. Lots of bugs have been fixed.
2998
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002999The process for making major new changes to the language has changed
3000since Python 1.6. Enhancements must now be documented by a Python
3001Enhancement Proposal (PEP) before they can be accepted.
3002
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003003There are several important syntax enhancements, described in more
3004detail below:
3005
3006 - Augmented assignment, e.g. x += 1
3007
3008 - List comprehensions, e.g. [x**2 for x in range(10)]
3009
3010 - Extended import statement, e.g. import Module as Name
3011
3012 - Extended print statement, e.g. print >> file, "Hello"
3013
3014Other important changes:
3015
3016 - Optional collection of cyclical garbage
3017
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003018Python Enhancement Proposal (PEP)
3019---------------------------------
3020
3021PEP stands for Python Enhancement Proposal. A PEP is a design
3022document providing information to the Python community, or describing
3023a new feature for Python. The PEP should provide a concise technical
3024specification of the feature and a rationale for the feature.
3025
3026We intend PEPs to be the primary mechanisms for proposing new
3027features, for collecting community input on an issue, and for
3028documenting the design decisions that have gone into Python. The PEP
3029author is responsible for building consensus within the community and
3030documenting dissenting opinions.
3031
3032The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003033
3034Augmented Assignment
3035--------------------
3036
3037This must have been the most-requested feature of the past years!
3038Eleven new assignment operators were added:
3039
Guido van Rossume905e952000-09-05 12:42:46 +00003040 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003041
3042For example,
3043
3044 A += B
3045
3046is similar to
3047
3048 A = A + B
3049
3050except that A is evaluated only once (relevant when A is something
3051like dict[index].attr).
3052
3053However, if A is a mutable object, A may be modified in place. Thus,
3054if A is a number or a string, A += B has the same effect as A = A+B
3055(except A is only evaluated once); but if a is a list, A += B has the
3056same effect as A.extend(B)!
3057
3058Classes and built-in object types can override the new operators in
3059order to implement the in-place behavior; the not-in-place behavior is
3060used automatically as a fallback when an object doesn't implement the
3061in-place behavior. For classes, the method name is derived from the
3062method name for the corresponding not-in-place operator by inserting
3063an 'i' in front of the name, e.g. __iadd__ implements in-place
3064__add__.
3065
3066Augmented assignment was implemented by Thomas Wouters.
3067
3068
3069List Comprehensions
3070-------------------
3071
3072This is a flexible new notation for lists whose elements are computed
3073from another list (or lists). The simplest form is:
3074
3075 [<expression> for <variable> in <sequence>]
3076
Guido van Rossum56db0952000-09-06 23:34:25 +00003077For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003078This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003079
3080You can also add a condition:
3081
3082 [<expression> for <variable> in <sequence> if <condition>]
3083
3084For example, [w for w in words if w == w.lower()] would yield the list
3085of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003086than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003087
3088You can also have nested for loops and more than one 'if' clause. For
3089example, here's a function that flattens a sequence of sequences::
3090
3091 def flatten(seq):
3092 return [x for subseq in seq for x in subseq]
3093
3094 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3095
3096This prints
3097
3098 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3099
3100List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003101Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003102
3103
3104Extended Import Statement
3105-------------------------
3106
3107Many people have asked for a way to import a module under a different
3108name. This can be accomplished like this:
3109
3110 import foo
3111 bar = foo
3112 del foo
3113
3114but this common idiom gets old quickly. A simple extension of the
3115import statement now allows this to be written as follows:
3116
3117 import foo as bar
3118
3119There's also a variant for 'from ... import':
3120
3121 from foo import bar as spam
3122
3123This also works with packages; e.g. you can write this:
3124
3125 import test.regrtest as regrtest
3126
3127Note that 'as' is not a new keyword -- it is recognized only in this
3128context (this is only possible because the syntax for the import
3129statement doesn't involve expressions).
3130
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003131Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003132
3133
3134Extended Print Statement
3135------------------------
3136
3137Easily the most controversial new feature, this extension to the print
3138statement adds an option to make the output go to a different file
3139than the default sys.stdout.
3140
3141For example, to write an error message to sys.stderr, you can now
3142write:
3143
3144 print >> sys.stderr, "Error: bad dog!"
3145
3146As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003147evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003148
3149 print >> None, "Hello world"
3150
3151is equivalent to
3152
3153 print "Hello world"
3154
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003155Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003156
3157
3158Optional Collection of Cyclical Garbage
3159---------------------------------------
3160
3161Python is now equipped with a garbage collector that can hunt down
3162cyclical references between Python objects. It's no replacement for
3163reference counting; in fact, it depends on the reference counts being
3164correct, and decides that a set of objects belong to a cycle if all
3165their reference counts can be accounted for from their references to
3166each other. This devious scheme was first proposed by Eric Tiedemann,
3167and brought to implementation by Neil Schemenauer.
3168
3169There's a module "gc" that lets you control some parameters of the
3170garbage collection. There's also an option to the configure script
3171that lets you enable or disable the garbage collection. In 2.0b1,
3172it's on by default, so that we (hopefully) can collect decent user
3173experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003174performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003175off by default in the final 2.0 release.
3176
3177
3178Smaller Changes
3179---------------
3180
3181A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3182map(None, seq1, seq2, ...) when the sequences have the same length;
3183i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3184the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003185zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003186
3187sys.version_info is a tuple (major, minor, micro, level, serial).
3188
3189Dictionaries have an odd new method, setdefault(key, default).
3190dict.setdefault(key, default) returns dict[key] if it exists; if not,
3191it sets dict[key] to default and returns that value. Thus:
3192
3193 dict.setdefault(key, []).append(item)
3194
3195does the same work as this common idiom:
3196
3197 if not dict.has_key(key):
3198 dict[key] = []
3199 dict[key].append(item)
3200
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003201There are two new variants of SyntaxError that are raised for
3202indentation-related errors: IndentationError and TabError.
3203
3204Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3205escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003206
3207The limits on the size of expressions and file in Python source code
3208have been raised from 2**16 to 2**32. Previous versions of Python
3209were limited because the maximum argument size the Python VM accepted
3210was 2**16. This limited the size of object constructor expressions,
3211e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3212limit was raised thanks to a patch by Charles Waldman that effectively
3213fixes the problem. It is now much more likely that you will be
3214limited by available memory than by an arbitrary limit in Python.
3215
3216The interpreter's maximum recursion depth can be modified by Python
3217programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3218limit is the maximum number of recursive calls that can be made by
3219Python code. The limit exists to prevent infinite recursion from
3220overflowing the C stack and causing a core dump. The default value is
32211000. The maximum safe value for a particular platform can be found
3222by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003223
3224New Modules and Packages
3225------------------------
3226
3227atexit - for registering functions to be called when Python exits.
3228
3229imputil - Greg Stein's alternative API for writing custom import
3230hooks.
3231
3232pyexpat - an interface to the Expat XML parser, contributed by Paul
3233Prescod.
3234
3235xml - a new package with XML support code organized (so far) in three
3236subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3237would fill a volume. There's a special feature whereby a
3238user-installed package named _xmlplus overrides the standard
3239xmlpackage; this is intended to give the XML SIG a hook to distribute
3240backwards-compatible updates to the standard xml package.
3241
3242webbrowser - a platform-independent API to launch a web browser.
3243
3244
Guido van Rossume905e952000-09-05 12:42:46 +00003245Changed Modules
3246---------------
3247
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003248array -- new methods for array objects: count, extend, index, pop, and
3249remove
3250
3251binascii -- new functions b2a_hex and a2b_hex that convert between
3252binary data and its hex representation
3253
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003254calendar -- Many new functions that support features including control
3255over which day of the week is the first day, returning strings instead
3256of printing them. Also new symbolic constants for days of week,
3257e.g. MONDAY, ..., SUNDAY.
3258
3259cgi -- FieldStorage objects have a getvalue method that works like a
3260dictionary's get method and returns the value attribute of the object.
3261
3262ConfigParser -- The parser object has new methods has_option,
3263remove_section, remove_option, set, and write. They allow the module
3264to be used for writing config files as well as reading them.
3265
3266ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003267optionally support the RFC 959 REST command.
3268
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003269gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003270
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003271httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3272the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003273
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003274locale -- implement getdefaultlocale for Win32 and Macintosh
3275
3276marshal -- no longer dumps core when marshaling deeply nested or
3277recursive data structures
3278
3279os -- new functions isatty, seteuid, setegid, setreuid, setregid
3280
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003281os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3282support under Unix.
3283
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003284os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003285
3286os.path -- fix semantics of os.path.commonprefix
3287
3288smtplib -- support for sending very long messages
3289
3290socket -- new function getfqdn()
3291
3292readline -- new functions to read, write and truncate history files.
3293The readline section of the library reference manual contains an
3294example.
3295
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003296select -- add interface to poll system call
3297
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003298shutil -- new copyfileobj function
3299
3300SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3301HTTP server.
3302
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003303Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003304
3305urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003306e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003307
3308whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003309
3310
3311Obsolete Modules
3312----------------
3313
3314None. However note that 1.6 made a whole slew of modules obsolete:
3315stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3316poly, zmod, strop, util, whatsound.
3317
3318
3319Changed, New, Obsolete Tools
3320----------------------------
3321
Tim Peters8b092332000-09-05 20:15:25 +00003322None.
Guido van Rossume905e952000-09-05 12:42:46 +00003323
3324
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003325C-level Changes
3326---------------
3327
3328Several cleanup jobs were carried out throughout the source code.
3329
3330All C code was converted to ANSI C; we got rid of all uses of the
3331Py_PROTO() macro, which makes the header files a lot more readable.
3332
3333Most of the portability hacks were moved to a new header file,
3334pyport.h; several other new header files were added and some old
3335header files were removed, in an attempt to create a more rational set
3336of header files. (Few of these ever need to be included explicitly;
3337they are all included by Python.h.)
3338
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003339Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003340and Win64, especially for the new Intel Itanium processor. Mick also
3341added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003342
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003343The C APIs to return an object's size have been update to consistently
3344use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3345previous versions, the abstract interfaces used PyXXX_Length and the
3346concrete interfaces used PyXXX_Size. The old names,
3347e.g. PyObject_Length, are still available for backwards compatibility
3348at the API level, but are deprecated.
3349
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003350The PyOS_CheckStack function has been implemented on Windows by
3351Fredrik Lundh. It prevents Python from failing with a stack overflow
3352on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003353
3354The GC changes resulted in creation of two new slots on object,
3355tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003356the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003357
3358The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003359C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003360
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003361PyErr_Format has been updated to automatically calculate the size of
3362the buffer needed to hold the formatted result string. This change
3363prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003364
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003365New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003366
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003367PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3368that are the same as their non-Ex counterparts except they take an
3369extra flag argument that tells them to close the file when done.
3370
3371XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003372
Tim Peters8b092332000-09-05 20:15:25 +00003373
3374Windows Changes
3375---------------
3376
3377New popen2/popen3/peopen4 in os module (see Changed Modules above).
3378
3379os.popen is much more usable on Windows 95 and 98. See Microsoft
3380Knowledge Base article Q150956. The Win9x workaround described there
3381is implemented by the new w9xpopen.exe helper in the root of your
3382Python installation. Note that Python uses this internally; it is not
3383a standalone program.
3384
3385Administrator privileges are no longer required to install Python
3386on Windows NT or Windows 2000. If you have administrator privileges,
3387Python's registry info will be written under HKEY_LOCAL_MACHINE.
3388Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003389under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003390uses of Python, but will prevent some advanced uses from working
3391(for example, running a Python script as an NT service, or possibly
3392from CGI).
3393
3394[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3395installer; instead, it installs the needed Tcl/Tk files directly in the
3396Python directory. If you already have a Tcl/Tk installation, this
3397wastes some disk space (about 4 Megs) but avoids problems with
3398conflicting Tcl/Tk installations, and makes it much easier for Python
3399to ensure that Tcl/Tk can find all its files.
3400
3401[This was new in 1.6] The Windows installer now installs by default in
3402\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3403
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003404
3405Updates to the changes between 1.5.2 and 1.6
3406--------------------------------------------
3407
3408The 1.6 NEWS file can't be changed after the release is done, so here
3409is some late-breaking news:
3410
3411New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3412and changes to getlocale() and setlocale().
3413
3414The new module is now enabled per default.
3415
3416It is not true that the encodings codecs cannot be used for normal
3417strings: the string.encode() (which is also present on 8-bit strings
3418!) allows using them for 8-bit strings too, e.g. to convert files from
3419cp1252 (Windows) to latin-1 or vice-versa.
3420
3421Japanese codecs are available from Tamito KAJIYAMA:
3422http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3423
3424
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003425======================================================================